diff options
Diffstat (limited to 'Documentation')
96 files changed, 5207 insertions, 561 deletions
diff --git a/Documentation/ABI/removed/o2cb b/Documentation/ABI/removed/o2cb index 7f5daa46509..20c91adca6d 100644 --- a/Documentation/ABI/removed/o2cb +++ b/Documentation/ABI/removed/o2cb @@ -1,6 +1,6 @@ What: /sys/o2cb symlink Date: May 2011 -KernelVersion: 2.6.40 +KernelVersion: 3.0 Contact: ocfs2-devel@oss.oracle.com Description: This is a symlink: /sys/o2cb to /sys/fs/o2cb. The symlink is removed when new versions of ocfs2-tools which know to look diff --git a/Documentation/ABI/removed/raw1394 b/Documentation/ABI/removed/raw1394 index 490aa1efc4a..ec333e67632 100644 --- a/Documentation/ABI/removed/raw1394 +++ b/Documentation/ABI/removed/raw1394 @@ -5,7 +5,7 @@ Description: /dev/raw1394 was a character device file that allowed low-level access to FireWire buses. Its major drawbacks were its inability to implement sensible device security policies, and its low level - of abstraction that required userspace clients do duplicate much + of abstraction that required userspace clients to duplicate much of the kernel's ieee1394 core functionality. Replaced by /dev/fw*, i.e. the <linux/firewire-cdev.h> ABI of firewire-core. diff --git a/Documentation/ABI/testing/evm b/Documentation/ABI/testing/evm new file mode 100644 index 00000000000..8374d4557e5 --- /dev/null +++ b/Documentation/ABI/testing/evm @@ -0,0 +1,23 @@ +What: security/evm +Date: March 2011 +Contact: Mimi Zohar <zohar@us.ibm.com> +Description: + EVM protects a file's security extended attributes(xattrs) + against integrity attacks. The initial method maintains an + HMAC-sha1 value across the extended attributes, storing the + value as the extended attribute 'security.evm'. + + EVM depends on the Kernel Key Retention System to provide it + with a trusted/encrypted key for the HMAC-sha1 operation. + The key is loaded onto the root's keyring using keyctl. Until + EVM receives notification that the key has been successfully + loaded onto the keyring (echo 1 > <securityfs>/evm), EVM + can not create or validate the 'security.evm' xattr, but + returns INTEGRITY_UNKNOWN. Loading the key and signaling EVM + should be done as early as possible. Normally this is done + in the initramfs, which has already been measured as part + of the trusted boot. For more information on creating and + loading existing trusted/encrypted keys, refer to: + Documentation/keys-trusted-encrypted.txt. (A sample dracut + patch, which loads the trusted/encrypted key and enables + EVM, is available from http://linux-ima.sourceforge.net/#EVM.) diff --git a/Documentation/ABI/testing/sysfs-bus-bcma b/Documentation/ABI/testing/sysfs-bus-bcma index 06b62badddd..721b4aea302 100644 --- a/Documentation/ABI/testing/sysfs-bus-bcma +++ b/Documentation/ABI/testing/sysfs-bus-bcma @@ -1,6 +1,6 @@ What: /sys/bus/bcma/devices/.../manuf Date: May 2011 -KernelVersion: 2.6.40 +KernelVersion: 3.0 Contact: Rafał Miłecki <zajec5@gmail.com> Description: Each BCMA core has it's manufacturer id. See @@ -8,7 +8,7 @@ Description: What: /sys/bus/bcma/devices/.../id Date: May 2011 -KernelVersion: 2.6.40 +KernelVersion: 3.0 Contact: Rafał Miłecki <zajec5@gmail.com> Description: There are a few types of BCMA cores, they can be identified by @@ -16,7 +16,7 @@ Description: What: /sys/bus/bcma/devices/.../rev Date: May 2011 -KernelVersion: 2.6.40 +KernelVersion: 3.0 Contact: Rafał Miłecki <zajec5@gmail.com> Description: BCMA cores of the same type can still slightly differ depending @@ -24,7 +24,7 @@ Description: What: /sys/bus/bcma/devices/.../class Date: May 2011 -KernelVersion: 2.6.40 +KernelVersion: 3.0 Contact: Rafał Miłecki <zajec5@gmail.com> Description: Each BCMA core is identified by few fields, including class it diff --git a/Documentation/ABI/testing/sysfs-bus-pci-drivers-ehci_hcd b/Documentation/ABI/testing/sysfs-bus-pci-drivers-ehci_hcd new file mode 100644 index 00000000000..60c60fa624b --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-pci-drivers-ehci_hcd @@ -0,0 +1,46 @@ +What: /sys/bus/pci/drivers/ehci_hcd/.../companion + /sys/bus/usb/devices/usbN/../companion +Date: January 2007 +KernelVersion: 2.6.21 +Contact: Alan Stern <stern@rowland.harvard.edu> +Description: + PCI-based EHCI USB controllers (i.e., high-speed USB-2.0 + controllers) are often implemented along with a set of + "companion" full/low-speed USB-1.1 controllers. When a + high-speed device is plugged in, the connection is routed + to the EHCI controller; when a full- or low-speed device + is plugged in, the connection is routed to the companion + controller. + + Sometimes you want to force a high-speed device to connect + at full speed, which can be accomplished by forcing the + connection to be routed to the companion controller. + That's what this file does. Writing a port number to the + file causes connections on that port to be routed to the + companion controller, and writing the negative of a port + number returns the port to normal operation. + + For example: To force the high-speed device attached to + port 4 on bus 2 to run at full speed: + + echo 4 >/sys/bus/usb/devices/usb2/../companion + + To return the port to high-speed operation: + + echo -4 >/sys/bus/usb/devices/usb2/../companion + + Reading the file gives the list of ports currently forced + to the companion controller. + + Note: Some EHCI controllers do not have companions; they + may contain an internal "transaction translator" or they + may be attached directly to a "rate-matching hub". This + mechanism will not work with such controllers. Also, it + cannot be used to force a port on a high-speed hub to + connect at full speed. + + Note: When this file was first added, it appeared in a + different sysfs directory. The location given above is + correct for 2.6.35 (and probably several earlier kernel + versions as well). + diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index 294aa864a60..e647378e9e8 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -142,3 +142,18 @@ Description: such devices. Users: usb_modeswitch + +What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm +Date: September 2011 +Contact: Andiry Xu <andiry.xu@amd.com> +Description: + If CONFIG_USB_SUSPEND is set and a USB 2.0 lpm-capable device + is plugged in to a xHCI host which support link PM, it will + perform a LPM test; if the test is passed and host supports + USB2 hardware LPM (xHCI 1.0 feature), USB2 hardware LPM will + be enabled for the device and the USB device directory will + contain a file named power/usb2_hardware_lpm. The file holds + a string value (enable or disable) indicating whether or not + USB2 hardware LPM is enabled for the device. Developer can + write y/Y/1 or n/N/0 to the file to enable/disable the + feature. diff --git a/Documentation/ABI/testing/sysfs-class-backlight-driver-adp8870 b/Documentation/ABI/testing/sysfs-class-backlight-driver-adp8870 index aa11dbdd794..4a9c545bda4 100644 --- a/Documentation/ABI/testing/sysfs-class-backlight-driver-adp8870 +++ b/Documentation/ABI/testing/sysfs-class-backlight-driver-adp8870 @@ -4,8 +4,8 @@ What: /sys/class/backlight/<backlight>/l2_bright_max What: /sys/class/backlight/<backlight>/l3_office_max What: /sys/class/backlight/<backlight>/l4_indoor_max What: /sys/class/backlight/<backlight>/l5_dark_max -Date: Mai 2011 -KernelVersion: 2.6.40 +Date: May 2011 +KernelVersion: 3.0 Contact: device-drivers-devel@blackfin.uclinux.org Description: Control the maximum brightness for <ambient light zone> @@ -18,8 +18,8 @@ What: /sys/class/backlight/<backlight>/l2_bright_dim What: /sys/class/backlight/<backlight>/l3_office_dim What: /sys/class/backlight/<backlight>/l4_indoor_dim What: /sys/class/backlight/<backlight>/l5_dark_dim -Date: Mai 2011 -KernelVersion: 2.6.40 +Date: May 2011 +KernelVersion: 3.0 Contact: device-drivers-devel@blackfin.uclinux.org Description: Control the dim brightness for <ambient light zone> @@ -29,8 +29,8 @@ Description: this <ambient light zone>. What: /sys/class/backlight/<backlight>/ambient_light_level -Date: Mai 2011 -KernelVersion: 2.6.40 +Date: May 2011 +KernelVersion: 3.0 Contact: device-drivers-devel@blackfin.uclinux.org Description: Get conversion value of the light sensor. @@ -39,8 +39,8 @@ Description: 8000 (max ambient brightness) What: /sys/class/backlight/<backlight>/ambient_light_zone -Date: Mai 2011 -KernelVersion: 2.6.40 +Date: May 2011 +KernelVersion: 3.0 Contact: device-drivers-devel@blackfin.uclinux.org Description: Get/Set current ambient light zone. Reading returns diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq new file mode 100644 index 00000000000..23d78b5aab1 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-devfreq @@ -0,0 +1,52 @@ +What: /sys/class/devfreq/.../ +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + Provide a place in sysfs for the devfreq objects. + This allows accessing various devfreq specific variables. + The name of devfreq object denoted as ... is same as the + name of device using devfreq. + +What: /sys/class/devfreq/.../governor +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + The /sys/class/devfreq/.../governor shows the name of the + governor used by the corresponding devfreq object. + +What: /sys/class/devfreq/.../cur_freq +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + The /sys/class/devfreq/.../cur_freq shows the current + frequency of the corresponding devfreq object. + +What: /sys/class/devfreq/.../central_polling +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + The /sys/class/devfreq/.../central_polling shows whether + the devfreq ojbect is using devfreq-provided central + polling mechanism or not. + +What: /sys/class/devfreq/.../polling_interval +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + The /sys/class/devfreq/.../polling_interval shows and sets + the requested polling interval of the corresponding devfreq + object. The values are represented in ms. If the value is + less than 1 jiffy, it is considered to be 0, which means + no polling. This value is meaningless if the governor is + not polling; thus. If the governor is not using + devfreq-provided central polling + (/sys/class/devfreq/.../central_polling is 0), this value + may be useless. + +What: /sys/class/devfreq/.../userspace/set_freq +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + The /sys/class/devfreq/.../userspace/set_freq shows and + sets the requested frequency for the devfreq object if + userspace governor is in effect. diff --git a/Documentation/ABI/testing/sysfs-class-net-mesh b/Documentation/ABI/testing/sysfs-class-net-mesh index 748fe1701d2..b02001488ee 100644 --- a/Documentation/ABI/testing/sysfs-class-net-mesh +++ b/Documentation/ABI/testing/sysfs-class-net-mesh @@ -22,6 +22,14 @@ Description: mesh will be fragmented or silently discarded if the packet size exceeds the outgoing interface MTU. +What: /sys/class/net/<mesh_iface>/mesh/ap_isolation +Date: May 2011 +Contact: Antonio Quartulli <ordex@autistici.org> +Description: + Indicates whether the data traffic going from a + wireless client to another wireless client will be + silently dropped. + What: /sys/class/net/<mesh_iface>/mesh/gw_bandwidth Date: October 2010 Contact: Marek Lindner <lindner_marek@yahoo.de> diff --git a/Documentation/ABI/testing/sysfs-class-scsi_host b/Documentation/ABI/testing/sysfs-class-scsi_host new file mode 100644 index 00000000000..29a4f892e43 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-scsi_host @@ -0,0 +1,13 @@ +What: /sys/class/scsi_host/hostX/isci_id +Date: June 2011 +Contact: Dave Jiang <dave.jiang@intel.com> +Description: + This file contains the enumerated host ID for the Intel + SCU controller. The Intel(R) C600 Series Chipset SATA/SAS + Storage Control Unit embeds up to two 4-port controllers in + a single PCI device. The controllers are enumerated in order + which usually means the lowest number scsi_host corresponds + with the first controller, but this association is not + guaranteed. The 'isci_id' attribute unambiguously identifies + the controller index: '0' for the first controller, + '1' for the second. diff --git a/Documentation/ABI/testing/sysfs-driver-hid-logitech-lg4ff b/Documentation/ABI/testing/sysfs-driver-hid-logitech-lg4ff new file mode 100644 index 00000000000..9aec8ef228b --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-hid-logitech-lg4ff @@ -0,0 +1,7 @@ +What: /sys/module/hid_logitech/drivers/hid:logitech/<dev>/range. +Date: July 2011 +KernelVersion: 3.2 +Contact: Michal Mal <madcatxster@gmail.com> +Description: Display minimum, maximum and current range of the steering + wheel. Writing a value within min and max boundaries sets the + range of the wheel. diff --git a/Documentation/DocBook/80211.tmpl b/Documentation/DocBook/80211.tmpl index 445289cd0e6..2014155c899 100644 --- a/Documentation/DocBook/80211.tmpl +++ b/Documentation/DocBook/80211.tmpl @@ -433,8 +433,18 @@ Insert notes about VLAN interfaces with hw crypto here or in the hw crypto chapter. </para> + <section id="ps-client"> + <title>support for powersaving clients</title> +!Pinclude/net/mac80211.h AP support for powersaving clients + </section> !Finclude/net/mac80211.h ieee80211_get_buffered_bc !Finclude/net/mac80211.h ieee80211_beacon_get +!Finclude/net/mac80211.h ieee80211_sta_eosp_irqsafe +!Finclude/net/mac80211.h ieee80211_frame_release_type +!Finclude/net/mac80211.h ieee80211_sta_ps_transition +!Finclude/net/mac80211.h ieee80211_sta_ps_transition_ni +!Finclude/net/mac80211.h ieee80211_sta_set_buffered +!Finclude/net/mac80211.h ieee80211_sta_block_awake </chapter> <chapter id="multi-iface"> @@ -460,7 +470,6 @@ !Finclude/net/mac80211.h sta_notify_cmd !Finclude/net/mac80211.h ieee80211_find_sta !Finclude/net/mac80211.h ieee80211_find_sta_by_ifaddr -!Finclude/net/mac80211.h ieee80211_sta_block_awake </chapter> <chapter id="hardware-scan-offload"> diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml index 85164016ed2..23fdf79f8cf 100644 --- a/Documentation/DocBook/media/v4l/controls.xml +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -1455,7 +1455,7 @@ Applicable to the H264 encoder.</entry> </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-video-h264-vui-sar-idc"> <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_IDC</constant> </entry> <entry>enum v4l2_mpeg_video_h264_vui_sar_idc</entry> </row> @@ -1561,7 +1561,7 @@ Applicable to the H264 encoder.</entry> </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-video-h264-level"> <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LEVEL</constant> </entry> <entry>enum v4l2_mpeg_video_h264_level</entry> </row> @@ -1641,7 +1641,7 @@ Possible values are:</entry> </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-video-mpeg4-level"> <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL</constant> </entry> <entry>enum v4l2_mpeg_video_mpeg4_level</entry> </row> @@ -1689,9 +1689,9 @@ Possible values are:</entry> </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-video-h264-profile"> <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_PROFILE</constant> </entry> - <entry>enum v4l2_mpeg_h264_profile</entry> + <entry>enum v4l2_mpeg_video_h264_profile</entry> </row> <row><entry spanname="descr">The profile information for H264. Applicable to the H264 encoder. @@ -1774,9 +1774,9 @@ Possible values are:</entry> </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-video-mpeg4-profile"> <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_PROFILE</constant> </entry> - <entry>enum v4l2_mpeg_mpeg4_profile</entry> + <entry>enum v4l2_mpeg_video_mpeg4_profile</entry> </row> <row><entry spanname="descr">The profile information for MPEG4. Applicable to the MPEG4 encoder. @@ -1820,9 +1820,9 @@ Applicable to the encoder. </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-video-multi-slice-mode"> <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE</constant> </entry> - <entry>enum v4l2_mpeg_multi_slice_mode</entry> + <entry>enum v4l2_mpeg_video_multi_slice_mode</entry> </row> <row><entry spanname="descr">Determines how the encoder should handle division of frame into slices. Applicable to the encoder. @@ -1868,9 +1868,9 @@ Applicable to the encoder.</entry> </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-video-h264-loop-filter-mode"> <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_MODE</constant> </entry> - <entry>enum v4l2_mpeg_h264_loop_filter_mode</entry> + <entry>enum v4l2_mpeg_video_h264_loop_filter_mode</entry> </row> <row><entry spanname="descr">Loop filter mode for H264 encoder. Possible values are:</entry> @@ -1913,9 +1913,9 @@ Applicable to the H264 encoder.</entry> </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-video-h264-entropy-mode"> <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_ENTROPY_MODE</constant> </entry> - <entry>enum v4l2_mpeg_h264_symbol_mode</entry> + <entry>enum v4l2_mpeg_video_h264_entropy_mode</entry> </row> <row><entry spanname="descr">Entropy coding mode for H264 - CABAC/CAVALC. Applicable to the H264 encoder. @@ -2140,9 +2140,9 @@ previous frames. Applicable to the H264 encoder.</entry> </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-video-header-mode"> <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_HEADER_MODE</constant> </entry> - <entry>enum v4l2_mpeg_header_mode</entry> + <entry>enum v4l2_mpeg_video_header_mode</entry> </row> <row><entry spanname="descr">Determines whether the header is returned as the first buffer or is it returned together with the first frame. Applicable to encoders. @@ -2320,9 +2320,9 @@ Valid only when H.264 and macroblock level RC is enabled (<constant>V4L2_CID_MPE Applicable to the H264 encoder.</entry> </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-mfc51-video-frame-skip-mode"> <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_FRAME_SKIP_MODE</constant> </entry> - <entry>enum v4l2_mpeg_mfc51_frame_skip_mode</entry> + <entry>enum v4l2_mpeg_mfc51_video_frame_skip_mode</entry> </row> <row><entry spanname="descr"> Indicates in what conditions the encoder should skip frames. If encoding a frame would cause the encoded stream to be larger then @@ -2361,9 +2361,9 @@ the stream will meet tight bandwidth contraints. Applicable to encoders. </entry> </row> <row><entry></entry></row> - <row> + <row id="v4l2-mpeg-mfc51-video-force-frame-type"> <entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE</constant> </entry> - <entry>enum v4l2_mpeg_mfc51_force_frame_type</entry> + <entry>enum v4l2_mpeg_mfc51_video_force_frame_type</entry> </row> <row><entry spanname="descr">Force a frame type for the next queued buffer. Applicable to encoders. Possible values are:</entry> diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl index 7c4b514d62b..54883de5d5f 100644 --- a/Documentation/DocBook/uio-howto.tmpl +++ b/Documentation/DocBook/uio-howto.tmpl @@ -529,7 +529,7 @@ memory (e.g. allocated with <function>kmalloc()</function>). There's also </para></listitem> <listitem><para> -<varname>unsigned long addr</varname>: Required if the mapping is used. +<varname>phys_addr_t addr</varname>: Required if the mapping is used. Fill in the address of your memory block. This address is the one that appears in sysfs. </para></listitem> diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt index 3f5e0b09bed..53e6fca146d 100644 --- a/Documentation/PCI/MSI-HOWTO.txt +++ b/Documentation/PCI/MSI-HOWTO.txt @@ -45,7 +45,7 @@ arrived in memory (this becomes more likely with devices behind PCI-PCI bridges). In order to ensure that all the data has arrived in memory, the interrupt handler must read a register on the device which raised the interrupt. PCI transaction ordering rules require that all the data -arrives in memory before the value can be returned from the register. +arrive in memory before the value may be returned from the register. Using MSIs avoids this problem as the interrupt-generating write cannot pass the data writes, so by the time the interrupt is raised, the driver knows that all the data has arrived in memory. @@ -86,13 +86,13 @@ device. int pci_enable_msi(struct pci_dev *dev) -A successful call will allocate ONE interrupt to the device, regardless -of how many MSIs the device supports. The device will be switched from +A successful call allocates ONE interrupt to the device, regardless +of how many MSIs the device supports. The device is switched from pin-based interrupt mode to MSI mode. The dev->irq number is changed -to a new number which represents the message signaled interrupt. -This function should be called before the driver calls request_irq() -since enabling MSIs disables the pin-based IRQ and the driver will not -receive interrupts on the old interrupt. +to a new number which represents the message signaled interrupt; +consequently, this function should be called before the driver calls +request_irq(), because an MSI is delivered via a vector that is +different from the vector of a pin-based interrupt. 4.2.2 pci_enable_msi_block @@ -111,20 +111,20 @@ the device are in the range dev->irq to dev->irq + count - 1. If this function returns a negative number, it indicates an error and the driver should not attempt to request any more MSI interrupts for -this device. If this function returns a positive number, it will be -less than 'count' and indicate the number of interrupts that could have -been allocated. In neither case will the irq value have been -updated, nor will the device have been switched into MSI mode. +this device. If this function returns a positive number, it is +less than 'count' and indicates the number of interrupts that could have +been allocated. In neither case is the irq value updated or the device +switched into MSI mode. The device driver must decide what action to take if -pci_enable_msi_block() returns a value less than the number asked for. -Some devices can make use of fewer interrupts than the maximum they -request; in this case the driver should call pci_enable_msi_block() +pci_enable_msi_block() returns a value less than the number requested. +For instance, the driver could still make use of fewer interrupts; +in this case the driver should call pci_enable_msi_block() again. Note that it is not guaranteed to succeed, even when the 'count' has been reduced to the value returned from a previous call to pci_enable_msi_block(). This is because there are multiple constraints on the number of vectors that can be allocated; pci_enable_msi_block() -will return as soon as it finds any constraint that doesn't allow the +returns as soon as it finds any constraint that doesn't allow the call to succeed. 4.2.3 pci_disable_msi @@ -137,10 +137,10 @@ interrupt number and frees the previously allocated message signaled interrupt(s). The interrupt may subsequently be assigned to another device, so drivers should not cache the value of dev->irq. -A device driver must always call free_irq() on the interrupt(s) -for which it has called request_irq() before calling this function. -Failure to do so will result in a BUG_ON(), the device will be left with -MSI enabled and will leak its vector. +Before calling this function, a device driver must always call free_irq() +on any interrupt for which it previously called request_irq(). +Failure to do so results in a BUG_ON(), leaving the device with +MSI enabled and thus leaking its vector. 4.3 Using MSI-X @@ -155,10 +155,10 @@ struct msix_entry { }; This allows for the device to use these interrupts in a sparse fashion; -for example it could use interrupts 3 and 1027 and allocate only a +for example, it could use interrupts 3 and 1027 and yet allocate only a two-element array. The driver is expected to fill in the 'entry' value -in each element of the array to indicate which entries it wants the kernel -to assign interrupts for. It is invalid to fill in two entries with the +in each element of the array to indicate for which entries the kernel +should assign interrupts; it is invalid to fill in two entries with the same number. 4.3.1 pci_enable_msix @@ -168,10 +168,11 @@ int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec) Calling this function asks the PCI subsystem to allocate 'nvec' MSIs. The 'entries' argument is a pointer to an array of msix_entry structs which should be at least 'nvec' entries in size. On success, the -function will return 0 and the device will have been switched into -MSI-X interrupt mode. The 'vector' elements in each entry will have -been filled in with the interrupt number. The driver should then call -request_irq() for each 'vector' that it decides to use. +device is switched into MSI-X mode and the function returns 0. +The 'vector' member in each entry is populated with the interrupt number; +the driver should then call request_irq() for each 'vector' that it +decides to use. The device driver is responsible for keeping track of the +interrupts assigned to the MSI-X vectors so it can free them again later. If this function returns a negative number, it indicates an error and the driver should not attempt to allocate any more MSI-X interrupts for @@ -181,16 +182,14 @@ below. This function, in contrast with pci_enable_msi(), does not adjust dev->irq. The device will not generate interrupts for this interrupt -number once MSI-X is enabled. The device driver is responsible for -keeping track of the interrupts assigned to the MSI-X vectors so it can -free them again later. +number once MSI-X is enabled. Device drivers should normally call this function once per device during the initialization phase. -It is ideal if drivers can cope with a variable number of MSI-X interrupts, +It is ideal if drivers can cope with a variable number of MSI-X interrupts; there are many reasons why the platform may not be able to provide the -exact number a driver asks for. +exact number that a driver asks for. A request loop to achieve that might look like: @@ -212,15 +211,15 @@ static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec) void pci_disable_msix(struct pci_dev *dev) -This API should be used to undo the effect of pci_enable_msix(). It frees +This function should be used to undo the effect of pci_enable_msix(). It frees the previously allocated message signaled interrupts. The interrupts may subsequently be assigned to another device, so drivers should not cache the value of the 'vector' elements over a call to pci_disable_msix(). -A device driver must always call free_irq() on the interrupt(s) -for which it has called request_irq() before calling this function. -Failure to do so will result in a BUG_ON(), the device will be left with -MSI enabled and will leak its vector. +Before calling this function, a device driver must always call free_irq() +on any interrupt for which it previously called request_irq(). +Failure to do so results in a BUG_ON(), leaving the device with +MSI-X enabled and thus leaking its vector. 4.3.3 The MSI-X Table @@ -232,10 +231,10 @@ mask or unmask an interrupt, it should call disable_irq() / enable_irq(). 4.4 Handling devices implementing both MSI and MSI-X capabilities If a device implements both MSI and MSI-X capabilities, it can -run in either MSI mode or MSI-X mode but not both simultaneously. +run in either MSI mode or MSI-X mode, but not both simultaneously. This is a requirement of the PCI spec, and it is enforced by the PCI layer. Calling pci_enable_msi() when MSI-X is already enabled or -pci_enable_msix() when MSI is already enabled will result in an error. +pci_enable_msix() when MSI is already enabled results in an error. If a device driver wishes to switch between MSI and MSI-X at runtime, it must first quiesce the device, then switch it back to pin-interrupt mode, before calling pci_enable_msi() or pci_enable_msix() and resuming @@ -251,7 +250,7 @@ the MSI-X facilities in preference to the MSI facilities. As mentioned above, MSI-X supports any number of interrupts between 1 and 2048. In constrast, MSI is restricted to a maximum of 32 interrupts (and must be a power of two). In addition, the MSI interrupt vectors must -be allocated consecutively, so the system may not be able to allocate +be allocated consecutively, so the system might not be able to allocate as many vectors for MSI as it could for MSI-X. On some platforms, MSI interrupts must all be targeted at the same set of CPUs whereas MSI-X interrupts can all be targeted at different CPUs. @@ -281,7 +280,7 @@ disabled to enabled and back again. Using 'lspci -v' (as root) may show some devices with "MSI", "Message Signalled Interrupts" or "MSI-X" capabilities. Each of these capabilities -has an 'Enable' flag which will be followed with either "+" (enabled) +has an 'Enable' flag which is followed with either "+" (enabled) or "-" (disabled). @@ -298,7 +297,7 @@ The PCI stack provides three ways to disable MSIs: Some host chipsets simply don't support MSIs properly. If we're lucky, the manufacturer knows this and has indicated it in the ACPI -FADT table. In this case, Linux will automatically disable MSIs. +FADT table. In this case, Linux automatically disables MSIs. Some boards don't include this information in the table and so we have to detect them ourselves. The complete list of these is found near the quirk_disable_all_msi() function in drivers/pci/quirks.c. @@ -317,7 +316,7 @@ Some bridges allow you to enable MSIs by changing some bits in their PCI configuration space (especially the Hypertransport chipsets such as the nVidia nForce and Serverworks HT2000). As with host chipsets, Linux mostly knows about them and automatically enables MSIs if it can. -If you have a bridge which Linux doesn't yet know about, you can enable +If you have a bridge unknown to Linux, you can enable MSIs in configuration space using whatever method you know works, then enable MSIs on that bridge by doing: @@ -327,7 +326,7 @@ where $bridge is the PCI address of the bridge you've enabled (eg 0000:00:0e.0). To disable MSIs, echo 0 instead of 1. Changing this value should be -done with caution as it can break interrupt handling for all devices +done with caution as it could break interrupt handling for all devices below this bridge. Again, please notify linux-pci@vger.kernel.org of any bridges that need @@ -336,7 +335,7 @@ special handling. 5.3. Disabling MSIs on a single device Some devices are known to have faulty MSI implementations. Usually this -is handled in the individual device driver but occasionally it's necessary +is handled in the individual device driver, but occasionally it's necessary to handle this with a quirk. Some drivers have an option to disable use of MSI. While this is a convenient workaround for the driver author, it is not good practise, and should not be emulated. @@ -350,7 +349,7 @@ for your machine. You should also check your .config to be sure you have enabled CONFIG_PCI_MSI. Then, 'lspci -t' gives the list of bridges above a device. Reading -/sys/bus/pci/devices/*/msi_bus will tell you whether MSI are enabled (1) +/sys/bus/pci/devices/*/msi_bus will tell you whether MSIs are enabled (1) or disabled (0). If 0 is found in any of the msi_bus files belonging to bridges between the PCI root and the device, MSIs are disabled. diff --git a/Documentation/PCI/pci.txt b/Documentation/PCI/pci.txt index 6148d4080f8..aa09e5476bb 100644 --- a/Documentation/PCI/pci.txt +++ b/Documentation/PCI/pci.txt @@ -314,7 +314,7 @@ from the PCI device config space. Use the values in the pci_dev structure as the PCI "bus address" might have been remapped to a "host physical" address by the arch/chip-set specific kernel support. -See Documentation/IO-mapping.txt for how to access device registers +See Documentation/io-mapping.txt for how to access device registers or device memory. The device driver needs to call pci_request_region() to verify diff --git a/Documentation/blackfin/bfin-gpio-notes.txt b/Documentation/blackfin/bfin-gpio-notes.txt index f731c1e5647..d36b01f778b 100644 --- a/Documentation/blackfin/bfin-gpio-notes.txt +++ b/Documentation/blackfin/bfin-gpio-notes.txt @@ -1,5 +1,5 @@ /* - * File: Documentation/blackfin/bfin-gpio-note.txt + * File: Documentation/blackfin/bfin-gpio-notes.txt * Based on: * Author: * diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt index c6d84cfd2f5..e418dc0a708 100644 --- a/Documentation/block/biodoc.txt +++ b/Documentation/block/biodoc.txt @@ -186,7 +186,7 @@ a virtual address mapping (unlike the earlier scheme of virtual address do not have a corresponding kernel virtual address space mapping) and low-memory pages. -Note: Please refer to Documentation/PCI/PCI-DMA-mapping.txt for a discussion +Note: Please refer to Documentation/DMA-API-HOWTO.txt for a discussion on PCI high mem DMA aspects and mapping of scatter gather lists, and support for 64 bit PCI. diff --git a/Documentation/block/cfq-iosched.txt b/Documentation/block/cfq-iosched.txt index e578feed6d8..6d670f57045 100644 --- a/Documentation/block/cfq-iosched.txt +++ b/Documentation/block/cfq-iosched.txt @@ -43,3 +43,74 @@ If one sets slice_idle=0 and if storage supports NCQ, CFQ internally switches to IOPS mode and starts providing fairness in terms of number of requests dispatched. Note that this mode switching takes effect only for group scheduling. For non-cgroup users nothing should change. + +CFQ IO scheduler Idling Theory +=============================== +Idling on a queue is primarily about waiting for the next request to come +on same queue after completion of a request. In this process CFQ will not +dispatch requests from other cfq queues even if requests are pending there. + +The rationale behind idling is that it can cut down on number of seeks +on rotational media. For example, if a process is doing dependent +sequential reads (next read will come on only after completion of previous +one), then not dispatching request from other queue should help as we +did not move the disk head and kept on dispatching sequential IO from +one queue. + +CFQ has following service trees and various queues are put on these trees. + + sync-idle sync-noidle async + +All cfq queues doing synchronous sequential IO go on to sync-idle tree. +On this tree we idle on each queue individually. + +All synchronous non-sequential queues go on sync-noidle tree. Also any +request which are marked with REQ_NOIDLE go on this service tree. On this +tree we do not idle on individual queues instead idle on the whole group +of queues or the tree. So if there are 4 queues waiting for IO to dispatch +we will idle only once last queue has dispatched the IO and there is +no more IO on this service tree. + +All async writes go on async service tree. There is no idling on async +queues. + +CFQ has some optimizations for SSDs and if it detects a non-rotational +media which can support higher queue depth (multiple requests at in +flight at a time), then it cuts down on idling of individual queues and +all the queues move to sync-noidle tree and only tree idle remains. This +tree idling provides isolation with buffered write queues on async tree. + +FAQ +=== +Q1. Why to idle at all on queues marked with REQ_NOIDLE. + +A1. We only do tree idle (all queues on sync-noidle tree) on queues marked + with REQ_NOIDLE. This helps in providing isolation with all the sync-idle + queues. Otherwise in presence of many sequential readers, other + synchronous IO might not get fair share of disk. + + For example, if there are 10 sequential readers doing IO and they get + 100ms each. If a REQ_NOIDLE request comes in, it will be scheduled + roughly after 1 second. If after completion of REQ_NOIDLE request we + do not idle, and after a couple of milli seconds a another REQ_NOIDLE + request comes in, again it will be scheduled after 1second. Repeat it + and notice how a workload can lose its disk share and suffer due to + multiple sequential readers. + + fsync can generate dependent IO where bunch of data is written in the + context of fsync, and later some journaling data is written. Journaling + data comes in only after fsync has finished its IO (atleast for ext4 + that seemed to be the case). Now if one decides not to idle on fsync + thread due to REQ_NOIDLE, then next journaling write will not get + scheduled for another second. A process doing small fsync, will suffer + badly in presence of multiple sequential readers. + + Hence doing tree idling on threads using REQ_NOIDLE flag on requests + provides isolation from multiple sequential readers and at the same + time we do not idle on individual threads. + +Q2. When to specify REQ_NOIDLE +A2. I would think whenever one is doing synchronous write and not expecting + more writes to be dispatched from same context soon, should be able + to specify REQ_NOIDLE on writes and that probably should work well for + most of the cases. diff --git a/Documentation/bus-virt-phys-mapping.txt b/Documentation/bus-virt-phys-mapping.txt index 1b5aa10df84..2bc55ff3b4d 100644 --- a/Documentation/bus-virt-phys-mapping.txt +++ b/Documentation/bus-virt-phys-mapping.txt @@ -1,6 +1,6 @@ [ NOTE: The virt_to_bus() and bus_to_virt() functions have been superseded by the functionality provided by the PCI DMA interface - (see Documentation/PCI/PCI-DMA-mapping.txt). They continue + (see Documentation/DMA-API-HOWTO.txt). They continue to be documented below for historical purposes, but new code must not use them. --davidm 00/12/12 ] diff --git a/Documentation/cdrom/packet-writing.txt b/Documentation/cdrom/packet-writing.txt index 13c251d5add..2834170d821 100644 --- a/Documentation/cdrom/packet-writing.txt +++ b/Documentation/cdrom/packet-writing.txt @@ -109,7 +109,7 @@ this interface. (see http://tom.ist-im-web.de/download/pktcdvd ) For a description of the sysfs interface look into the file: - Documentation/ABI/testing/sysfs-block-pktcdvd + Documentation/ABI/testing/sysfs-class-pktcdvd Using the pktcdvd debugfs interface diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 6f3c598971f..06eb6d957c8 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -380,7 +380,7 @@ will be charged as a new owner of it. 5.2 stat file -5.2.1 memory.stat file includes following statistics +memory.stat file includes following statistics # per-memory cgroup local status cache - # of bytes of page cache memory. @@ -438,89 +438,6 @@ Note: file_mapped is accounted only when the memory cgroup is owner of page cache.) -5.2.2 memory.vmscan_stat - -memory.vmscan_stat includes statistics information for memory scanning and -freeing, reclaiming. The statistics shows memory scanning information since -memory cgroup creation and can be reset to 0 by writing 0 as - - #echo 0 > ../memory.vmscan_stat - -This file contains following statistics. - -[param]_[file_or_anon]_pages_by_[reason]_[under_heararchy] -[param]_elapsed_ns_by_[reason]_[under_hierarchy] - -For example, - - scanned_file_pages_by_limit indicates the number of scanned - file pages at vmscan. - -Now, 3 parameters are supported - - scanned - the number of pages scanned by vmscan - rotated - the number of pages activated at vmscan - freed - the number of pages freed by vmscan - -If "rotated" is high against scanned/freed, the memcg seems busy. - -Now, 2 reason are supported - - limit - the memory cgroup's limit - system - global memory pressure + softlimit - (global memory pressure not under softlimit is not handled now) - -When under_hierarchy is added in the tail, the number indicates the -total memcg scan of its children and itself. - -elapsed_ns is a elapsed time in nanosecond. This may include sleep time -and not indicates CPU usage. So, please take this as just showing -latency. - -Here is an example. - -# cat /cgroup/memory/A/memory.vmscan_stat -scanned_pages_by_limit 9471864 -scanned_anon_pages_by_limit 6640629 -scanned_file_pages_by_limit 2831235 -rotated_pages_by_limit 4243974 -rotated_anon_pages_by_limit 3971968 -rotated_file_pages_by_limit 272006 -freed_pages_by_limit 2318492 -freed_anon_pages_by_limit 962052 -freed_file_pages_by_limit 1356440 -elapsed_ns_by_limit 351386416101 -scanned_pages_by_system 0 -scanned_anon_pages_by_system 0 -scanned_file_pages_by_system 0 -rotated_pages_by_system 0 -rotated_anon_pages_by_system 0 -rotated_file_pages_by_system 0 -freed_pages_by_system 0 -freed_anon_pages_by_system 0 -freed_file_pages_by_system 0 -elapsed_ns_by_system 0 -scanned_pages_by_limit_under_hierarchy 9471864 -scanned_anon_pages_by_limit_under_hierarchy 6640629 -scanned_file_pages_by_limit_under_hierarchy 2831235 -rotated_pages_by_limit_under_hierarchy 4243974 -rotated_anon_pages_by_limit_under_hierarchy 3971968 -rotated_file_pages_by_limit_under_hierarchy 272006 -freed_pages_by_limit_under_hierarchy 2318492 -freed_anon_pages_by_limit_under_hierarchy 962052 -freed_file_pages_by_limit_under_hierarchy 1356440 -elapsed_ns_by_limit_under_hierarchy 351386416101 -scanned_pages_by_system_under_hierarchy 0 -scanned_anon_pages_by_system_under_hierarchy 0 -scanned_file_pages_by_system_under_hierarchy 0 -rotated_pages_by_system_under_hierarchy 0 -rotated_anon_pages_by_system_under_hierarchy 0 -rotated_file_pages_by_system_under_hierarchy 0 -freed_pages_by_system_under_hierarchy 0 -freed_anon_pages_by_system_under_hierarchy 0 -freed_file_pages_by_system_under_hierarchy 0 -elapsed_ns_by_system_under_hierarchy 0 - 5.3 swappiness Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only. diff --git a/Documentation/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt index e74d0a2eb1c..d221781daba 100644 --- a/Documentation/cpu-freq/governors.txt +++ b/Documentation/cpu-freq/governors.txt @@ -132,7 +132,7 @@ The sampling rate is limited by the HW transition latency: transition_latency * 100 Or by kernel restrictions: If CONFIG_NO_HZ is set, the limit is 10ms fixed. -If CONFIG_NO_HZ is not set or no_hz=off boot parameter is used, the +If CONFIG_NO_HZ is not set or nohz=off boot parameter is used, the limits depend on the CONFIG_HZ option: HZ=1000: min=20000us (20ms) HZ=250: min=80000us (80ms) diff --git a/Documentation/development-process/4.Coding b/Documentation/development-process/4.Coding index 83f5f5b365a..e3cb6a56653 100644 --- a/Documentation/development-process/4.Coding +++ b/Documentation/development-process/4.Coding @@ -278,7 +278,7 @@ enabled, a configurable percentage of memory allocations will be made to fail; these failures can be restricted to a specific range of code. Running with fault injection enabled allows the programmer to see how the code responds when things go badly. See -Documentation/fault-injection/fault-injection.text for more information on +Documentation/fault-injection/fault-injection.txt for more information on how to use this facility. Other kinds of errors can be found with the "sparse" static analysis tool. diff --git a/Documentation/devicetree/bindings/arm/l2cc.txt b/Documentation/devicetree/bindings/arm/l2cc.txt new file mode 100644 index 00000000000..7ca52161e7a --- /dev/null +++ b/Documentation/devicetree/bindings/arm/l2cc.txt @@ -0,0 +1,44 @@ +* ARM L2 Cache Controller + +ARM cores often have a separate level 2 cache controller. There are various +implementations of the L2 cache controller with compatible programming models. +The ARM L2 cache representation in the device tree should be done as follows: + +Required properties: + +- compatible : should be one of: + "arm,pl310-cache" + "arm,l220-cache" + "arm,l210-cache" +- cache-unified : Specifies the cache is a unified cache. +- cache-level : Should be set to 2 for a level 2 cache. +- reg : Physical base address and size of cache controller's memory mapped + registers. + +Optional properties: + +- arm,data-latency : Cycles of latency for Data RAM accesses. Specifies 3 cells of + read, write and setup latencies. Minimum valid values are 1. Controllers + without setup latency control should use a value of 0. +- arm,tag-latency : Cycles of latency for Tag RAM accesses. Specifies 3 cells of + read, write and setup latencies. Controllers without setup latency control + should use 0. Controllers without separate read and write Tag RAM latency + values should only use the first cell. +- arm,dirty-latency : Cycles of latency for Dirty RAMs. This is a single cell. +- arm,filter-ranges : <start length> Starting address and length of window to + filter. Addresses in the filter window are directed to the M1 port. Other + addresses will go to the M0 port. +- interrupts : 1 combined interrupt. + +Example: + +L2: cache-controller { + compatible = "arm,pl310-cache"; + reg = <0xfff12000 0x1000>; + arm,data-latency = <1 1 1>; + arm,tag-latency = <2 2 2>; + arm,filter-latency = <0x80000000 0x8000000>; + cache-unified; + cache-level = <2>; + interrupts = <45>; +}; diff --git a/Documentation/devicetree/bindings/gpio/led.txt b/Documentation/devicetree/bindings/gpio/led.txt index 064db928c3c..141087cf310 100644 --- a/Documentation/devicetree/bindings/gpio/led.txt +++ b/Documentation/devicetree/bindings/gpio/led.txt @@ -8,7 +8,7 @@ node's name represents the name of the corresponding LED. LED sub-node properties: - gpios : Should specify the LED's GPIO, see "Specifying GPIO information - for devices" in Documentation/powerpc/booting-without-of.txt. Active + for devices" in Documentation/devicetree/booting-without-of.txt. Active low LEDs should be indicated using flags in the GPIO specifier. - label : (optional) The label for this LED. If omitted, the label is taken from the node name (excluding the unit address). diff --git a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt index 1a729f08986..1ad80d5865a 100644 --- a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt +++ b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt @@ -1,61 +1,24 @@ -CAN Device Tree Bindings ------------------------- -2011 Freescale Semiconductor, Inc. +Flexcan CAN contoller on Freescale's ARM and PowerPC system-on-a-chip (SOC). -fsl,flexcan-v1.0 nodes ------------------------ -In addition to the required compatible-, reg- and interrupt-properties, you can -also specify which clock source shall be used for the controller. +Required properties: -CPI Clock- Can Protocol Interface Clock - This CLK_SRC bit of CTRL(control register) selects the clock source to - the CAN Protocol Interface(CPI) to be either the peripheral clock - (driven by the PLL) or the crystal oscillator clock. The selected clock - is the one fed to the prescaler to generate the Serial Clock (Sclock). - The PRESDIV field of CTRL(control register) controls a prescaler that - generates the Serial Clock (Sclock), whose period defines the - time quantum used to compose the CAN waveform. +- compatible : Should be "fsl,<processor>-flexcan" -Can Engine Clock Source - There are two sources for CAN clock - - Platform Clock It represents the bus clock - - Oscillator Clock + An implementation should also claim any of the following compatibles + that it is fully backwards compatible with: - Peripheral Clock (PLL) - -------------- - | - --------- ------------- - | |CPI Clock | Prescaler | Sclock - | |---------------->| (1.. 256) |------------> - --------- ------------- - | | - -------------- ---------------------CLK_SRC - Oscillator Clock + - fsl,p1010-flexcan -- fsl,flexcan-clock-source : CAN Engine Clock Source.This property selects - the peripheral clock. PLL clock is fed to the - prescaler to generate the Serial Clock (Sclock). - Valid values are "oscillator" and "platform" - "oscillator": CAN engine clock source is oscillator clock. - "platform" The CAN engine clock source is the bus clock - (platform clock). +- reg : Offset and length of the register set for this device +- interrupts : Interrupt tuple for this device +- clock-frequency : The oscillator frequency driving the flexcan device -- fsl,flexcan-clock-divider : for the reference and system clock, an additional - clock divider can be specified. -- clock-frequency: frequency required to calculate the bitrate for FlexCAN. +Example: -Note: - - v1.0 of flexcan-v1.0 represent the IP block version for P1010 SOC. - - P1010 does not have oscillator as the Clock Source.So the default - Clock Source is platform clock. -Examples: - - can0@1c000 { - compatible = "fsl,flexcan-v1.0"; + can@1c000 { + compatible = "fsl,p1010-flexcan"; reg = <0x1c000 0x1000>; interrupts = <48 0x2>; interrupt-parent = <&mpic>; - fsl,flexcan-clock-source = "platform"; - fsl,flexcan-clock-divider = <2>; - clock-frequency = <fixed by u-boot>; + clock-frequency = <200000000>; // filled in by bootloader }; diff --git a/Documentation/devicetree/bindings/net/smsc911x.txt b/Documentation/devicetree/bindings/net/smsc911x.txt new file mode 100644 index 00000000000..adb5b5744ec --- /dev/null +++ b/Documentation/devicetree/bindings/net/smsc911x.txt @@ -0,0 +1,38 @@ +* Smart Mixed-Signal Connectivity (SMSC) LAN911x/912x Controller + +Required properties: +- compatible : Should be "smsc,lan<model>", "smsc,lan9115" +- reg : Address and length of the io space for SMSC LAN +- interrupts : Should contain SMSC LAN interrupt line +- interrupt-parent : Should be the phandle for the interrupt controller + that services interrupts for this device +- phy-mode : String, operation mode of the PHY interface. + Supported values are: "mii", "gmii", "sgmii", "tbi", "rmii", + "rgmii", "rgmii-id", "rgmii-rxid", "rgmii-txid", "rtbi", "smii". + +Optional properties: +- reg-shift : Specify the quantity to shift the register offsets by +- reg-io-width : Specify the size (in bytes) of the IO accesses that + should be performed on the device. Valid value for SMSC LAN is + 2 or 4. If it's omitted or invalid, the size would be 2. +- smsc,irq-active-high : Indicates the IRQ polarity is active-high +- smsc,irq-push-pull : Indicates the IRQ type is push-pull +- smsc,force-internal-phy : Forces SMSC LAN controller to use + internal PHY +- smsc,force-external-phy : Forces SMSC LAN controller to use + external PHY +- smsc,save-mac-address : Indicates that mac address needs to be saved + before resetting the controller +- local-mac-address : 6 bytes, mac address + +Examples: + +lan9220@f4000000 { + compatible = "smsc,lan9220", "smsc,lan9115"; + reg = <0xf4000000 0x2000000>; + phy-mode = "mii"; + interrupt-parent = <&gpio1>; + interrupts = <31>; + reg-io-width = <4>; + smsc,irq-push-pull; +}; diff --git a/Documentation/devicetree/bindings/serial/rs485.txt b/Documentation/devicetree/bindings/serial/rs485.txt new file mode 100644 index 00000000000..1e753c69fc8 --- /dev/null +++ b/Documentation/devicetree/bindings/serial/rs485.txt @@ -0,0 +1,31 @@ +* RS485 serial communications + +The RTS signal is capable of automatically controlling line direction for +the built-in half-duplex mode. +The properties described hereafter shall be given to a half-duplex capable +UART node. + +Required properties: +- rs485-rts-delay: prop-encoded-array <a b> where: + * a is the delay beteween rts signal and beginning of data sent in milliseconds. + it corresponds to the delay before sending data. + * b is the delay between end of data sent and rts signal in milliseconds + it corresponds to the delay after sending data and actual release of the line. + +Optional properties: +- linux,rs485-enabled-at-boot-time: empty property telling to enable the rs485 + feature at boot time. It can be disabled later with proper ioctl. +- rs485-rx-during-tx: empty property that enables the receiving of data even + whilst sending data. + +RS485 example for Atmel USART: + usart0: serial@fff8c000 { + compatible = "atmel,at91sam9260-usart"; + reg = <0xfff8c000 0x4000>; + interrupts = <7>; + atmel,use-dma-rx; + atmel,use-dma-tx; + linux,rs485-enabled-at-boot-time; + rs485-rts-delay = <0 200>; // in milliseconds + }; + diff --git a/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt b/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt new file mode 100644 index 00000000000..a49d9a1d4cc --- /dev/null +++ b/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt @@ -0,0 +1,27 @@ +* Atmel Universal Synchronous Asynchronous Receiver/Transmitter (USART) + +Required properties: +- compatible: Should be "atmel,<chip>-usart" + The compatible <chip> indicated will be the first SoC to support an + additional mode or an USART new feature. +- reg: Should contain registers location and length +- interrupts: Should contain interrupt + +Optional properties: +- atmel,use-dma-rx: use of PDC or DMA for receiving data +- atmel,use-dma-tx: use of PDC or DMA for transmitting data + +<chip> compatible description: +- at91rm9200: legacy USART support +- at91sam9260: generic USART implementation for SAM9 SoCs + +Example: + + usart0: serial@fff8c000 { + compatible = "atmel,at91sam9260-usart"; + reg = <0xfff8c000 0x4000>; + interrupts = <7>; + atmel,use-dma-rx; + atmel,use-dma-tx; + }; + diff --git a/Documentation/devicetree/bindings/tty/serial/snps-dw-apb-uart.txt b/Documentation/devicetree/bindings/tty/serial/snps-dw-apb-uart.txt new file mode 100644 index 00000000000..f13f1c5be91 --- /dev/null +++ b/Documentation/devicetree/bindings/tty/serial/snps-dw-apb-uart.txt @@ -0,0 +1,25 @@ +* Synopsys DesignWare ABP UART + +Required properties: +- compatible : "snps,dw-apb-uart" +- reg : offset and length of the register set for the device. +- interrupts : should contain uart interrupt. +- clock-frequency : the input clock frequency for the UART. + +Optional properties: +- reg-shift : quantity to shift the register offsets by. If this property is + not present then the register offsets are not shifted. +- reg-io-width : the size (in bytes) of the IO accesses that should be + performed on the device. If this property is not present then single byte + accesses are used. + +Example: + + uart@80230000 { + compatible = "snps,dw-apb-uart"; + reg = <0x80230000 0x100>; + clock-frequency = <3686400>; + interrupts = <10>; + reg-shift = <2>; + reg-io-width = <4>; + }; diff --git a/Documentation/driver-model/binding.txt b/Documentation/driver-model/binding.txt index f7ec9d625bf..abfc8e290d5 100644 --- a/Documentation/driver-model/binding.txt +++ b/Documentation/driver-model/binding.txt @@ -48,10 +48,6 @@ devclass_add_device is called to enumerate the device within the class and actually register it with the class, which happens with the class's register_dev callback. -NOTE: The device class structures and core routines to manipulate them -are not in the mainline kernel, so the discussion is still a bit -speculative. - Driver ~~~~~~ diff --git a/Documentation/driver-model/device.txt b/Documentation/driver-model/device.txt index bdefe728a73..1e70220d20f 100644 --- a/Documentation/driver-model/device.txt +++ b/Documentation/driver-model/device.txt @@ -45,33 +45,52 @@ struct device_attribute { const char *buf, size_t count); }; -Attributes of devices can be exported via drivers using a simple -procfs-like interface. +Attributes of devices can be exported by a device driver through sysfs. Please see Documentation/filesystems/sysfs.txt for more information on how sysfs works. +As explained in Documentation/kobject.txt, device attributes must be be +created before the KOBJ_ADD uevent is generated. The only way to realize +that is by defining an attribute group. + Attributes are declared using a macro called DEVICE_ATTR: #define DEVICE_ATTR(name,mode,show,store) Example: -DEVICE_ATTR(power,0644,show_power,store_power); +static DEVICE_ATTR(type, 0444, show_type, NULL); +static DEVICE_ATTR(power, 0644, show_power, store_power); -This declares a structure of type struct device_attribute named -'dev_attr_power'. This can then be added and removed to the device's -directory using: +This declares two structures of type struct device_attribute with respective +names 'dev_attr_type' and 'dev_attr_power'. These two attributes can be +organized as follows into a group: -int device_create_file(struct device *device, struct device_attribute * entry); -void device_remove_file(struct device * dev, struct device_attribute * attr); +static struct attribute *dev_attrs[] = { + &dev_attr_type.attr, + &dev_attr_power.attr, + NULL, +}; -Example: +static struct attribute_group dev_attr_group = { + .attrs = dev_attrs, +}; + +static const struct attribute_group *dev_attr_groups[] = { + &dev_attr_group, + NULL, +}; + +This array of groups can then be associated with a device by setting the +group pointer in struct device before device_register() is invoked: -device_create_file(dev,&dev_attr_power); -device_remove_file(dev,&dev_attr_power); + dev->groups = dev_attr_groups; + device_register(dev); -The file name will be 'power' with a mode of 0644 (-rw-r--r--). +The device_register() function will use the 'groups' pointer to create the +device attributes and the device_unregister() function will use this pointer +to remove the device attributes. Word of warning: While the kernel allows device_create_file() and device_remove_file() to be called on a device at any time, userspace has @@ -84,24 +103,4 @@ not know about the new attributes. This is important for device driver that need to publish additional attributes for a device at driver probe time. If the device driver simply calls device_create_file() on the device structure passed to it, then -userspace will never be notified of the new attributes. Instead, it should -probably use class_create() and class->dev_attrs to set up a list of -desired attributes in the modules_init function, and then in the .probe() -hook, and then use device_create() to create a new device as a child -of the probed device. The new device will generate a new uevent and -properly advertise the new attributes to userspace. - -For example, if a driver wanted to add the following attributes: -struct device_attribute mydriver_attribs[] = { - __ATTR(port_count, 0444, port_count_show), - __ATTR(serial_number, 0444, serial_number_show), - NULL -}; - -Then in the module init function is would do: - mydriver_class = class_create(THIS_MODULE, "my_attrs"); - mydriver_class.dev_attr = mydriver_attribs; - -And assuming 'dev' is the struct device passed into the probe hook, the driver -probe function would do something like: - device_create(&mydriver_class, dev, chrdev, &private_data, "my_name"); +userspace will never be notified of the new attributes. diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index c4a6e148732..d5ac362daef 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -592,3 +592,20 @@ Why: In 3.0, we can now autodetect internal 3G device and already have interface that was used by acer-wmi driver. It will replaced by information log when acer-wmi initial. Who: Lee, Chun-Yi <jlee@novell.com> + +---------------------------- + +What: The XFS nodelaylog mount option +When: 3.3 +Why: The delaylog mode that has been the default since 2.6.39 has proven + stable, and the old code is in the way of additional improvements in + the log code. +Who: Christoph Hellwig <hch@lst.de> + +---------------------------- + +What: iwlagn alias support +When: 3.5 +Why: The iwlagn module has been renamed iwlwifi. The alias will be around + for backward compatibility for several cycles and then dropped. +Who: Don Fry <donald.h.fry@intel.com> diff --git a/Documentation/filesystems/9p.txt b/Documentation/filesystems/9p.txt index 13de64c7f0a..2c032144284 100644 --- a/Documentation/filesystems/9p.txt +++ b/Documentation/filesystems/9p.txt @@ -92,7 +92,7 @@ OPTIONS wfdno=n the file descriptor for writing with trans=fd - maxdata=n the number of bytes to use for 9p packet payload (msize) + msize=n the number of bytes to use for 9p packet payload port=n port to connect to on the remote server diff --git a/Documentation/filesystems/caching/object.txt b/Documentation/filesystems/caching/object.txt index e8b0a35d8fe..58313348da8 100644 --- a/Documentation/filesystems/caching/object.txt +++ b/Documentation/filesystems/caching/object.txt @@ -127,9 +127,9 @@ fscache_enqueue_object()). PROVISION OF CPU TIME --------------------- -The work to be done by the various states is given CPU time by the threads of -the slow work facility (see Documentation/slow-work.txt). This is used in -preference to the workqueue facility because: +The work to be done by the various states was given CPU time by the threads of +the slow work facility. This was used in preference to the workqueue facility +because: (1) Threads may be completely occupied for very long periods of time by a particular work item. These state actions may be doing sequences of diff --git a/Documentation/filesystems/locks.txt b/Documentation/filesystems/locks.txt index fab857accbd..2cf81082581 100644 --- a/Documentation/filesystems/locks.txt +++ b/Documentation/filesystems/locks.txt @@ -53,11 +53,12 @@ fcntl(), with all the problems that implies. 1.3 Mandatory Locking As A Mount Option --------------------------------------- -Mandatory locking, as described in 'Documentation/filesystems/mandatory.txt' -was prior to this release a general configuration option that was valid for -all mounted filesystems. This had a number of inherent dangers, not the -least of which was the ability to freeze an NFS server by asking it to read -a file for which a mandatory lock existed. +Mandatory locking, as described in +'Documentation/filesystems/mandatory-locking.txt' was prior to this release a +general configuration option that was valid for all mounted filesystems. This +had a number of inherent dangers, not the least of which was the ability to +freeze an NFS server by asking it to read a file for which a mandatory lock +existed. From this release of the kernel, mandatory locking can be turned on and off on a per-filesystem basis, using the mount options 'mand' and 'nomand'. diff --git a/Documentation/filesystems/nfs/idmapper.txt b/Documentation/filesystems/nfs/idmapper.txt index 9c8fd614865..120fd3cf7fd 100644 --- a/Documentation/filesystems/nfs/idmapper.txt +++ b/Documentation/filesystems/nfs/idmapper.txt @@ -47,7 +47,7 @@ request-key will find the first matching line and corresponding program. In this case, /some/other/program will handle all uid lookups and /usr/sbin/nfs.idmap will handle gid, user, and group lookups. -See <file:Documentation/security/keys-request-keys.txt> for more information +See <file:Documentation/security/keys-request-key.txt> for more information about the request-key function. diff --git a/Documentation/filesystems/pohmelfs/design_notes.txt b/Documentation/filesystems/pohmelfs/design_notes.txt index dcf83358716..8aef9133570 100644 --- a/Documentation/filesystems/pohmelfs/design_notes.txt +++ b/Documentation/filesystems/pohmelfs/design_notes.txt @@ -58,8 +58,9 @@ data transfers. POHMELFS clients operate with a working set of servers and are capable of balancing read-only operations (like lookups or directory listings) between them according to IO priorities. Administrators can add or remove servers from the set at run-time via special commands (described -in Documentation/pohmelfs/info.txt file). Writes are replicated to all servers, which are connected -with write permission turned on. IO priority and permissions can be changed in run-time. +in Documentation/filesystems/pohmelfs/info.txt file). Writes are replicated to all servers, which +are connected with write permission turned on. IO priority and permissions can be changed in +run-time. POHMELFS is capable of full data channel encryption and/or strong crypto hashing. One can select any kernel supported cipher, encryption mode, hash type and operation mode diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index db3b1aba32a..0ec91f03422 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -1263,7 +1263,7 @@ review the kernel documentation in the directory /usr/src/linux/Documentation. This chapter is heavily based on the documentation included in the pre 2.2 kernels, and became part of it in version 2.2.1 of the Linux kernel. -Please see: Documentation/sysctls/ directory for descriptions of these +Please see: Documentation/sysctl/ directory for descriptions of these entries. ------------------------------------------------------------------------------ diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt index 597f728e7b4..07235caec22 100644 --- a/Documentation/filesystems/sysfs.txt +++ b/Documentation/filesystems/sysfs.txt @@ -4,7 +4,7 @@ sysfs - _The_ filesystem for exporting kernel objects. Patrick Mochel <mochel@osdl.org> Mike Murphy <mamurph@cs.clemson.edu> -Revised: 15 July 2010 +Revised: 16 August 2011 Original: 10 January 2003 @@ -370,3 +370,11 @@ int driver_create_file(struct device_driver *, const struct driver_attribute *); void driver_remove_file(struct device_driver *, const struct driver_attribute *); +Documentation +~~~~~~~~~~~~~ + +The sysfs directory structure and the attributes in each directory define an +ABI between the kernel and user space. As for any ABI, it is important that +this ABI is stable and properly documented. All new sysfs attributes must be +documented in Documentation/ABI. See also Documentation/ABI/README for more +information. diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 52d8fb81cff..43cbd082172 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -1053,9 +1053,6 @@ manipulate dentries: and the dentry is returned. The caller must use dput() to free the dentry when it finishes using it. -For further information on dentry locking, please refer to the document -Documentation/filesystems/dentry-locking.txt. - Mount Options ============= diff --git a/Documentation/frv/booting.txt b/Documentation/frv/booting.txt index 37c4d84a0e5..9bdf4b46e74 100644 --- a/Documentation/frv/booting.txt +++ b/Documentation/frv/booting.txt @@ -180,9 +180,3 @@ separated by spaces: This tells the kernel what program to run initially. By default this is /sbin/init, but /sbin/sash or /bin/sh are common alternatives. - - (*) vdc=... - - This option configures the MB93493 companion chip visual display - driver. Please see Documentation/frv/mb93493/vdc.txt for more - information. diff --git a/Documentation/hwmon/ad7314 b/Documentation/hwmon/ad7314 new file mode 100644 index 00000000000..1912549c746 --- /dev/null +++ b/Documentation/hwmon/ad7314 @@ -0,0 +1,25 @@ +Kernel driver ad7314 +==================== + +Supported chips: + * Analog Devices AD7314 + Prefix: 'ad7314' + Datasheet: Publicly available at Analog Devices website. + * Analog Devices ADT7301 + Prefix: 'adt7301' + Datasheet: Publicly available at Analog Devices website. + * Analog Devices ADT7302 + Prefix: 'adt7302' + Datasheet: Publicly available at Analog Devices website. + +Description +----------- + +Driver supports the above parts. The ad7314 has a 10 bit +sensor with 1lsb = 0.25 degrees centigrade. The adt7301 and +adt7302 have 14 bit sensors with 1lsb = 0.03125 degrees centigrade. + +Notes +----- + +Currently power down mode is not supported. diff --git a/Documentation/hwmon/adm1275 b/Documentation/hwmon/adm1275 index 097b3ccc4be..ab70d96d2df 100644 --- a/Documentation/hwmon/adm1275 +++ b/Documentation/hwmon/adm1275 @@ -6,6 +6,10 @@ Supported chips: Prefix: 'adm1275' Addresses scanned: - Datasheet: www.analog.com/static/imported-files/data_sheets/ADM1275.pdf + * Analog Devices ADM1276 + Prefix: 'adm1276' + Addresses scanned: - + Datasheet: www.analog.com/static/imported-files/data_sheets/ADM1276.pdf Author: Guenter Roeck <guenter.roeck@ericsson.com> @@ -13,13 +17,13 @@ Author: Guenter Roeck <guenter.roeck@ericsson.com> Description ----------- -This driver supports hardware montoring for Analog Devices ADM1275 Hot-Swap -Controller and Digital Power Monitor. +This driver supports hardware montoring for Analog Devices ADM1275 and ADM1276 +Hot-Swap Controller and Digital Power Monitor. -The ADM1275 is a hot-swap controller that allows a circuit board to be removed -from or inserted into a live backplane. It also features current and voltage -readback via an integrated 12-bit analog-to-digital converter (ADC), accessed -using a PMBus. interface. +ADM1275 and ADM1276 are hot-swap controllers that allow a circuit board to be +removed from or inserted into a live backplane. They also feature current and +voltage readback via an integrated 12-bit analog-to-digital converter (ADC), +accessed using a PMBus interface. The driver is a client driver to the core PMBus driver. Please see Documentation/hwmon/pmbus for details on PMBus client drivers. @@ -48,17 +52,25 @@ attributes are write-only, all other attributes are read-only. in1_label "vin1" or "vout1" depending on chip variant and configuration. -in1_input Measured voltage. From READ_VOUT register. -in1_min Minumum Voltage. From VOUT_UV_WARN_LIMIT register. -in1_max Maximum voltage. From VOUT_OV_WARN_LIMIT register. -in1_min_alarm Voltage low alarm. From VOLTAGE_UV_WARNING status. -in1_max_alarm Voltage high alarm. From VOLTAGE_OV_WARNING status. +in1_input Measured voltage. +in1_min Minumum Voltage. +in1_max Maximum voltage. +in1_min_alarm Voltage low alarm. +in1_max_alarm Voltage high alarm. in1_highest Historical maximum voltage. in1_reset_history Write any value to reset history. curr1_label "iout1" -curr1_input Measured current. From READ_IOUT register. -curr1_max Maximum current. From IOUT_OC_WARN_LIMIT register. -curr1_max_alarm Current high alarm. From IOUT_OC_WARN_LIMIT register. +curr1_input Measured current. +curr1_max Maximum current. +curr1_max_alarm Current high alarm. +curr1_lcrit Critical minimum current. Depending on the chip + configuration, either curr1_lcrit or curr1_crit is + supported, but not both. +curr1_lcrit_alarm Critical current low alarm. +curr1_crit Critical maximum current. Depending on the chip + configuration, either curr1_lcrit or curr1_crit is + supported, but not both. +curr1_crit_alarm Critical current high alarm. curr1_highest Historical maximum current. curr1_reset_history Write any value to reset history. diff --git a/Documentation/hwmon/coretemp b/Documentation/hwmon/coretemp index fa8776ab9b1..84d46c0c71a 100644 --- a/Documentation/hwmon/coretemp +++ b/Documentation/hwmon/coretemp @@ -35,13 +35,6 @@ the Out-Of-Spec bit. Following table summarizes the exported sysfs files: All Sysfs entries are named with their core_id (represented here by 'X'). tempX_input - Core temperature (in millidegrees Celsius). tempX_max - All cooling devices should be turned on (on Core2). - Initialized with IA32_THERM_INTERRUPT. When the CPU - temperature reaches this temperature, an interrupt is - generated and tempX_max_alarm is set. -tempX_max_hyst - If the CPU temperature falls below than temperature, - an interrupt is generated and tempX_max_alarm is reset. -tempX_max_alarm - Set if the temperature reaches or exceeds tempX_max. - Reset if the temperature drops to or below tempX_max_hyst. tempX_crit - Maximum junction temperature (in millidegrees Celsius). tempX_crit_alarm - Set when Out-of-spec bit is set, never clears. Correct CPU operation is no longer guaranteed. @@ -49,9 +42,10 @@ tempX_label - Contains string "Core X", where X is processor number. For Package temp, this will be "Physical id Y", where Y is the package number. -The TjMax temperature is set to 85 degrees C if undocumented model specific -register (UMSR) 0xee has bit 30 set. If not the TjMax is 100 degrees C as -(sometimes) documented in processor datasheet. +On CPU models which support it, TjMax is read from a model-specific register. +On other models, it is set to an arbitrary value based on weak heuristics. +If these heuristics don't work for you, you can pass the correct TjMax value +as a module parameter (tjmax). Appendix A. Known TjMax lists (TBD): Some information comes from ark.intel.com diff --git a/Documentation/hwmon/exynos4_tmu b/Documentation/hwmon/exynos4_tmu new file mode 100644 index 00000000000..c3c6b41db60 --- /dev/null +++ b/Documentation/hwmon/exynos4_tmu @@ -0,0 +1,81 @@ +Kernel driver exynos4_tmu +================= + +Supported chips: +* ARM SAMSUNG EXYNOS4 series of SoC + Prefix: 'exynos4-tmu' + Datasheet: Not publicly available + +Authors: Donggeun Kim <dg77.kim@samsung.com> + +Description +----------- + +This driver allows to read temperature inside SAMSUNG EXYNOS4 series of SoC. + +The chip only exposes the measured 8-bit temperature code value +through a register. +Temperature can be taken from the temperature code. +There are three equations converting from temperature to temperature code. + +The three equations are: + 1. Two point trimming + Tc = (T - 25) * (TI2 - TI1) / (85 - 25) + TI1 + + 2. One point trimming + Tc = T + TI1 - 25 + + 3. No trimming + Tc = T + 50 + + Tc: Temperature code, T: Temperature, + TI1: Trimming info for 25 degree Celsius (stored at TRIMINFO register) + Temperature code measured at 25 degree Celsius which is unchanged + TI2: Trimming info for 85 degree Celsius (stored at TRIMINFO register) + Temperature code measured at 85 degree Celsius which is unchanged + +TMU(Thermal Management Unit) in EXYNOS4 generates interrupt +when temperature exceeds pre-defined levels. +The maximum number of configurable threshold is four. +The threshold levels are defined as follows: + Level_0: current temperature > trigger_level_0 + threshold + Level_1: current temperature > trigger_level_1 + threshold + Level_2: current temperature > trigger_level_2 + threshold + Level_3: current temperature > trigger_level_3 + threshold + + The threshold and each trigger_level are set + through the corresponding registers. + +When an interrupt occurs, this driver notify user space of +one of four threshold levels for the interrupt +through kobject_uevent_env and sysfs_notify functions. +Although an interrupt condition for level_0 can be set, +it is not notified to user space through sysfs_notify function. + +Sysfs Interface +--------------- +name name of the temperature sensor + RO + +temp1_input temperature + RO + +temp1_max temperature for level_1 interrupt + RO + +temp1_crit temperature for level_2 interrupt + RO + +temp1_emergency temperature for level_3 interrupt + RO + +temp1_max_alarm alarm for level_1 interrupt + RO + +temp1_crit_alarm + alarm for level_2 interrupt + RO + +temp1_emergency_alarm + alarm for level_3 interrupt + RO diff --git a/Documentation/hwmon/lm75 b/Documentation/hwmon/lm75 index a1790401fdd..c91a1d15fa2 100644 --- a/Documentation/hwmon/lm75 +++ b/Documentation/hwmon/lm75 @@ -12,26 +12,46 @@ Supported chips: Addresses scanned: I2C 0x48 - 0x4f Datasheet: Publicly available at the National Semiconductor website http://www.national.com/ - * Dallas Semiconductor DS75 - Prefix: 'lm75' - Addresses scanned: I2C 0x48 - 0x4f - Datasheet: Publicly available at the Dallas Semiconductor website - http://www.maxim-ic.com/ - * Dallas Semiconductor DS1775 - Prefix: 'lm75' - Addresses scanned: I2C 0x48 - 0x4f + * Dallas Semiconductor DS75, DS1775 + Prefixes: 'ds75', 'ds1775' + Addresses scanned: none Datasheet: Publicly available at the Dallas Semiconductor website http://www.maxim-ic.com/ * Maxim MAX6625, MAX6626 - Prefix: 'lm75' - Addresses scanned: I2C 0x48 - 0x4b + Prefixes: 'max6625', 'max6626' + Addresses scanned: none Datasheet: Publicly available at the Maxim website http://www.maxim-ic.com/ * Microchip (TelCom) TCN75 Prefix: 'lm75' - Addresses scanned: I2C 0x48 - 0x4f + Addresses scanned: none + Datasheet: Publicly available at the Microchip website + http://www.microchip.com/ + * Microchip MCP9800, MCP9801, MCP9802, MCP9803 + Prefix: 'mcp980x' + Addresses scanned: none Datasheet: Publicly available at the Microchip website http://www.microchip.com/ + * Analog Devices ADT75 + Prefix: 'adt75' + Addresses scanned: none + Datasheet: Publicly available at the Analog Devices website + http://www.analog.com/adt75 + * ST Microelectronics STDS75 + Prefix: 'stds75' + Addresses scanned: none + Datasheet: Publicly available at the ST website + http://www.st.com/internet/analog/product/121769.jsp + * Texas Instruments TMP100, TMP101, TMP105, TMP75, TMP175, TMP275 + Prefixes: 'tmp100', 'tmp101', 'tmp105', 'tmp175', 'tmp75', 'tmp275' + Addresses scanned: none + Datasheet: Publicly available at the Texas Instruments website + http://www.ti.com/product/tmp100 + http://www.ti.com/product/tmp101 + http://www.ti.com/product/tmp105 + http://www.ti.com/product/tmp75 + http://www.ti.com/product/tmp175 + http://www.ti.com/product/tmp275 Author: Frodo Looijaard <frodol@dds.nl> @@ -50,21 +70,16 @@ range of -55 to +125 degrees. The LM75 only updates its values each 1.5 seconds; reading it more often will do no harm, but will return 'old' values. -The LM75 is usually used in combination with LM78-like chips, to measure -the temperature of the processor(s). - -The DS75, DS1775, MAX6625, and MAX6626 are supported as well. -They are not distinguished from an LM75. While most of these chips -have three additional bits of accuracy (12 vs. 9 for the LM75), -the additional bits are not supported. Not only that, but these chips will -not be detected if not in 9-bit precision mode (use the force parameter if -needed). - -The TCN75 is supported as well, and is not distinguished from an LM75. +The original LM75 was typically used in combination with LM78-like chips +on PC motherboards, to measure the temperature of the processor(s). Clones +are now used in various embedded designs. The LM75 is essentially an industry standard; there may be other LM75 clones not listed here, with or without various enhancements, -that are supported. +that are supported. The clones are not detected by the driver, unless +they reproduce the exact register tricks of the original LM75, and must +therefore be instantiated explicitly. The specific enhancements (such as +higher resolution) are not currently supported by the driver. The LM77 is not supported, contrary to what we pretended for a long time. Both chips are simply not compatible, value encoding differs. diff --git a/Documentation/hwmon/ltc2978 b/Documentation/hwmon/ltc2978 new file mode 100644 index 00000000000..c365f9beb5d --- /dev/null +++ b/Documentation/hwmon/ltc2978 @@ -0,0 +1,103 @@ +Kernel driver ltc2978 +===================== + +Supported chips: + * Linear Technology LTC2978 + Prefix: 'ltc2978' + Addresses scanned: - + Datasheet: http://cds.linear.com/docs/Datasheet/2978fa.pdf + * Linear Technology LTC3880 + Prefix: 'ltc3880' + Addresses scanned: - + Datasheet: http://cds.linear.com/docs/Datasheet/3880f.pdf + +Author: Guenter Roeck <guenter.roeck@ericsson.com> + + +Description +----------- + +The LTC2978 is an octal power supply monitor, supervisor, sequencer and +margin controller. The LTC3880 is a dual, PolyPhase DC/DC synchronous +step-down switching regulator controller. + + +Usage Notes +----------- + +This driver does not probe for PMBus devices. You will have to instantiate +devices explicitly. + +Example: the following commands will load the driver for an LTC2978 at address +0x60 on I2C bus #1: + +# modprobe ltc2978 +# echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device + + +Sysfs attributes +---------------- + +in1_label "vin" +in1_input Measured input voltage. +in1_min Minimum input voltage. +in1_max Maximum input voltage. +in1_lcrit Critical minimum input voltage. +in1_crit Critical maximum input voltage. +in1_min_alarm Input voltage low alarm. +in1_max_alarm Input voltage high alarm. +in1_lcrit_alarm Input voltage critical low alarm. +in1_crit_alarm Input voltage critical high alarm. +in1_lowest Lowest input voltage. LTC2978 only. +in1_highest Highest input voltage. +in1_reset_history Reset history. Writing into this attribute will reset + history for all attributes. + +in[2-9]_label "vout[1-8]". Channels 3 to 9 on LTC2978 only. +in[2-9]_input Measured output voltage. +in[2-9]_min Minimum output voltage. +in[2-9]_max Maximum output voltage. +in[2-9]_lcrit Critical minimum output voltage. +in[2-9]_crit Critical maximum output voltage. +in[2-9]_min_alarm Output voltage low alarm. +in[2-9]_max_alarm Output voltage high alarm. +in[2-9]_lcrit_alarm Output voltage critical low alarm. +in[2-9]_crit_alarm Output voltage critical high alarm. +in[2-9]_lowest Lowest output voltage. LTC2978 only. +in[2-9]_highest Lowest output voltage. +in[2-9]_reset_history Reset history. Writing into this attribute will reset + history for all attributes. + +temp[1-3]_input Measured temperature. + On LTC2978, only one temperature measurement is + supported and reflects the internal temperature. + On LTC3880, temp1 and temp2 report external + temperatures, and temp3 reports the internal + temperature. +temp[1-3]_min Mimimum temperature. +temp[1-3]_max Maximum temperature. +temp[1-3]_lcrit Critical low temperature. +temp[1-3]_crit Critical high temperature. +temp[1-3]_min_alarm Chip temperature low alarm. +temp[1-3]_max_alarm Chip temperature high alarm. +temp[1-3]_lcrit_alarm Chip temperature critical low alarm. +temp[1-3]_crit_alarm Chip temperature critical high alarm. +temp[1-3]_lowest Lowest measured temperature. LTC2978 only. +temp[1-3]_highest Highest measured temperature. +temp[1-3]_reset_history Reset history. Writing into this attribute will reset + history for all attributes. + +power[1-2]_label "pout[1-2]". LTC3880 only. +power[1-2]_input Measured power. + +curr1_label "iin". LTC3880 only. +curr1_input Measured input current. +curr1_max Maximum input current. +curr1_max_alarm Input current high alarm. + +curr[2-3]_label "iout[1-2]". LTC3880 only. +curr[2-3]_input Measured input current. +curr[2-3]_max Maximum input current. +curr[2-3]_crit Critical input current. +curr[2-3]_max_alarm Input current high alarm. +curr[2-3]_crit_alarm Input current critical high alarm. diff --git a/Documentation/hwmon/max16065 b/Documentation/hwmon/max16065 index 44b4f61e04f..c11f64a1f2a 100644 --- a/Documentation/hwmon/max16065 +++ b/Documentation/hwmon/max16065 @@ -62,6 +62,13 @@ can be safely used to identify the chip. You will have to instantiate the devices explicitly. Please see Documentation/i2c/instantiating-devices for details. +WARNING: Do not access chip registers using the i2cdump command, and do not use +any of the i2ctools commands on a command register (0xa5 to 0xac). The chips +supported by this driver interpret any access to a command register (including +read commands) as request to execute the command in question. This may result in +power loss, board resets, and/or Flash corruption. Worst case, your board may +turn into a brick. + Sysfs entries ------------- diff --git a/Documentation/hwmon/pmbus b/Documentation/hwmon/pmbus index c36c1c1a62b..15ac911ce51 100644 --- a/Documentation/hwmon/pmbus +++ b/Documentation/hwmon/pmbus @@ -8,11 +8,6 @@ Supported chips: Addresses scanned: - Datasheet: http://archive.ericsson.net/service/internet/picov/get?DocNo=28701-EN/LZT146395 - * Linear Technology LTC2978 - Octal PMBus Power Supply Monitor and Controller - Prefix: 'ltc2978' - Addresses scanned: - - Datasheet: http://cds.linear.com/docs/Datasheet/2978fa.pdf * ON Semiconductor ADP4000, NCP4200, NCP4208 Prefixes: 'adp4000', 'ncp4200', 'ncp4208' Addresses scanned: - @@ -20,6 +15,14 @@ Supported chips: http://www.onsemi.com/pub_link/Collateral/ADP4000-D.PDF http://www.onsemi.com/pub_link/Collateral/NCP4200-D.PDF http://www.onsemi.com/pub_link/Collateral/JUNE%202009-%20REV.%200.PDF + * Lineage Power + Prefixes: 'pdt003', 'pdt006', 'pdt012', 'udt020' + Addresses scanned: - + Datasheets: + http://www.lineagepower.com/oem/pdf/PDT003A0X.pdf + http://www.lineagepower.com/oem/pdf/PDT006A0X.pdf + http://www.lineagepower.com/oem/pdf/PDT012A0X.pdf + http://www.lineagepower.com/oem/pdf/UDT020A0X.pdf * Generic PMBus devices Prefix: 'pmbus' Addresses scanned: - diff --git a/Documentation/hwmon/pmbus-core b/Documentation/hwmon/pmbus-core new file mode 100644 index 00000000000..31e4720fed1 --- /dev/null +++ b/Documentation/hwmon/pmbus-core @@ -0,0 +1,283 @@ +PMBus core driver and internal API +================================== + +Introduction +============ + +[from pmbus.org] The Power Management Bus (PMBus) is an open standard +power-management protocol with a fully defined command language that facilitates +communication with power converters and other devices in a power system. The +protocol is implemented over the industry-standard SMBus serial interface and +enables programming, control, and real-time monitoring of compliant power +conversion products. This flexible and highly versatile standard allows for +communication between devices based on both analog and digital technologies, and +provides true interoperability which will reduce design complexity and shorten +time to market for power system designers. Pioneered by leading power supply and +semiconductor companies, this open power system standard is maintained and +promoted by the PMBus Implementers Forum (PMBus-IF), comprising 30+ adopters +with the objective to provide support to, and facilitate adoption among, users. + +Unfortunately, while PMBus commands are standardized, there are no mandatory +commands, and manufacturers can add as many non-standard commands as they like. +Also, different PMBUs devices act differently if non-supported commands are +executed. Some devices return an error, some devices return 0xff or 0xffff and +set a status error flag, and some devices may simply hang up. + +Despite all those difficulties, a generic PMBus device driver is still useful +and supported since kernel version 2.6.39. However, it was necessary to support +device specific extensions in addition to the core PMBus driver, since it is +simply unknown what new device specific functionality PMBus device developers +come up with next. + +To make device specific extensions as scalable as possible, and to avoid having +to modify the core PMBus driver repeatedly for new devices, the PMBus driver was +split into core, generic, and device specific code. The core code (in +pmbus_core.c) provides generic functionality. The generic code (in pmbus.c) +provides support for generic PMBus devices. Device specific code is responsible +for device specific initialization and, if needed, maps device specific +functionality into generic functionality. This is to some degree comparable +to PCI code, where generic code is augmented as needed with quirks for all kinds +of devices. + +PMBus device capabilities auto-detection +======================================== + +For generic PMBus devices, code in pmbus.c attempts to auto-detect all supported +PMBus commands. Auto-detection is somewhat limited, since there are simply too +many variables to consider. For example, it is almost impossible to autodetect +which PMBus commands are paged and which commands are replicated across all +pages (see the PMBus specification for details on multi-page PMBus devices). + +For this reason, it often makes sense to provide a device specific driver if not +all commands can be auto-detected. The data structures in this driver can be +used to inform the core driver about functionality supported by individual +chips. + +Some commands are always auto-detected. This applies to all limit commands +(lcrit, min, max, and crit attributes) as well as associated alarm attributes. +Limits and alarm attributes are auto-detected because there are simply too many +possible combinations to provide a manual configuration interface. + +PMBus internal API +================== + +The API between core and device specific PMBus code is defined in +drivers/hwmon/pmbus/pmbus.h. In addition to the internal API, pmbus.h defines +standard PMBus commands and virtual PMBus commands. + +Standard PMBus commands +----------------------- + +Standard PMBus commands (commands values 0x00 to 0xff) are defined in the PMBUs +specification. + +Virtual PMBus commands +---------------------- + +Virtual PMBus commands are provided to enable support for non-standard +functionality which has been implemented by several chip vendors and is thus +desirable to support. + +Virtual PMBus commands start with command value 0x100 and can thus easily be +distinguished from standard PMBus commands (which can not have values larger +than 0xff). Support for virtual PMBus commands is device specific and thus has +to be implemented in device specific code. + +Virtual commands are named PMBUS_VIRT_xxx and start with PMBUS_VIRT_BASE. All +virtual commands are word sized. + +There are currently two types of virtual commands. + +- READ commands are read-only; writes are either ignored or return an error. +- RESET commands are read/write. Reading reset registers returns zero + (used for detection), writing any value causes the associated history to be + reset. + +Virtual commands have to be handled in device specific driver code. Chip driver +code returns non-negative values if a virtual command is supported, or a +negative error code if not. The chip driver may return -ENODATA or any other +Linux error code in this case, though an error code other than -ENODATA is +handled more efficiently and thus preferred. Either case, the calling PMBus +core code will abort if the chip driver returns an error code when reading +or writing virtual registers (in other words, the PMBus core code will never +send a virtual command to a chip). + +PMBus driver information +------------------------ + +PMBus driver information, defined in struct pmbus_driver_info, is the main means +for device specific drivers to pass information to the core PMBus driver. +Specifically, it provides the following information. + +- For devices supporting its data in Direct Data Format, it provides coefficients + for converting register values into normalized data. This data is usually + provided by chip manufacturers in device datasheets. +- Supported chip functionality can be provided to the core driver. This may be + necessary for chips which react badly if non-supported commands are executed, + and/or to speed up device detection and initialization. +- Several function entry points are provided to support overriding and/or + augmenting generic command execution. This functionality can be used to map + non-standard PMBus commands to standard commands, or to augment standard + command return values with device specific information. + + API functions + ------------- + + Functions provided by chip driver + --------------------------------- + + All functions return the command return value (read) or zero (write) if + successful. A return value of -ENODATA indicates that there is no manufacturer + specific command, but that a standard PMBus command may exist. Any other + negative return value indicates that the commands does not exist for this + chip, and that no attempt should be made to read or write the standard + command. + + As mentioned above, an exception to this rule applies to virtual commands, + which _must_ be handled in driver specific code. See "Virtual PMBus Commands" + above for more details. + + Command execution in the core PMBus driver code is as follows. + + if (chip_access_function) { + status = chip_access_function(); + if (status != -ENODATA) + return status; + } + if (command >= PMBUS_VIRT_BASE) /* For word commands/registers only */ + return -EINVAL; + return generic_access(); + + Chip drivers may provide pointers to the following functions in struct + pmbus_driver_info. All functions are optional. + + int (*read_byte_data)(struct i2c_client *client, int page, int reg); + + Read byte from page <page>, register <reg>. + <page> may be -1, which means "current page". + + int (*read_word_data)(struct i2c_client *client, int page, int reg); + + Read word from page <page>, register <reg>. + + int (*write_word_data)(struct i2c_client *client, int page, int reg, + u16 word); + + Write word to page <page>, register <reg>. + + int (*write_byte)(struct i2c_client *client, int page, u8 value); + + Write byte to page <page>, register <reg>. + <page> may be -1, which means "current page". + + int (*identify)(struct i2c_client *client, struct pmbus_driver_info *info); + + Determine supported PMBus functionality. This function is only necessary + if a chip driver supports multiple chips, and the chip functionality is not + pre-determined. It is currently only used by the generic pmbus driver + (pmbus.c). + + Functions exported by core driver + --------------------------------- + + Chip drivers are expected to use the following functions to read or write + PMBus registers. Chip drivers may also use direct I2C commands. If direct I2C + commands are used, the chip driver code must not directly modify the current + page, since the selected page is cached in the core driver and the core driver + will assume that it is selected. Using pmbus_set_page() to select a new page + is mandatory. + + int pmbus_set_page(struct i2c_client *client, u8 page); + + Set PMBus page register to <page> for subsequent commands. + + int pmbus_read_word_data(struct i2c_client *client, u8 page, u8 reg); + + Read word data from <page>, <reg>. Similar to i2c_smbus_read_word_data(), but + selects page first. + + int pmbus_write_word_data(struct i2c_client *client, u8 page, u8 reg, + u16 word); + + Write word data to <page>, <reg>. Similar to i2c_smbus_write_word_data(), but + selects page first. + + int pmbus_read_byte_data(struct i2c_client *client, int page, u8 reg); + + Read byte data from <page>, <reg>. Similar to i2c_smbus_read_byte_data(), but + selects page first. <page> may be -1, which means "current page". + + int pmbus_write_byte(struct i2c_client *client, int page, u8 value); + + Write byte data to <page>, <reg>. Similar to i2c_smbus_write_byte(), but + selects page first. <page> may be -1, which means "current page". + + void pmbus_clear_faults(struct i2c_client *client); + + Execute PMBus "Clear Fault" command on all chip pages. + This function calls the device specific write_byte function if defined. + Therefore, it must _not_ be called from that function. + + bool pmbus_check_byte_register(struct i2c_client *client, int page, int reg); + + Check if byte register exists. Return true if the register exists, false + otherwise. + This function calls the device specific write_byte function if defined to + obtain the chip status. Therefore, it must _not_ be called from that function. + + bool pmbus_check_word_register(struct i2c_client *client, int page, int reg); + + Check if word register exists. Return true if the register exists, false + otherwise. + This function calls the device specific write_byte function if defined to + obtain the chip status. Therefore, it must _not_ be called from that function. + + int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id, + struct pmbus_driver_info *info); + + Execute probe function. Similar to standard probe function for other drivers, + with the pointer to struct pmbus_driver_info as additional argument. Calls + identify function if supported. Must only be called from device probe + function. + + void pmbus_do_remove(struct i2c_client *client); + + Execute driver remove function. Similar to standard driver remove function. + + const struct pmbus_driver_info + *pmbus_get_driver_info(struct i2c_client *client); + + Return pointer to struct pmbus_driver_info as passed to pmbus_do_probe(). + + +PMBus driver platform data +========================== + +PMBus platform data is defined in include/linux/i2c/pmbus.h. Platform data +currently only provides a flag field with a single bit used. + +#define PMBUS_SKIP_STATUS_CHECK (1 << 0) + +struct pmbus_platform_data { + u32 flags; /* Device specific flags */ +}; + + +Flags +----- + +PMBUS_SKIP_STATUS_CHECK + +During register detection, skip checking the status register for +communication or command errors. + +Some PMBus chips respond with valid data when trying to read an unsupported +register. For such chips, checking the status register is mandatory when +trying to determine if a chip register exists or not. +Other PMBus chips don't support the STATUS_CML register, or report +communication errors for no explicable reason. For such chips, checking the +status register must be disabled. + +Some i2c controllers do not support single-byte commands (write commands with +no data, i2c_smbus_write_byte()). With such controllers, clearing the status +register is impossible, and the PMBUS_SKIP_STATUS_CHECK flag must be set. diff --git a/Documentation/hwmon/zl6100 b/Documentation/hwmon/zl6100 new file mode 100644 index 00000000000..7617798b5c9 --- /dev/null +++ b/Documentation/hwmon/zl6100 @@ -0,0 +1,125 @@ +Kernel driver zl6100 +==================== + +Supported chips: + * Intersil / Zilker Labs ZL2004 + Prefix: 'zl2004' + Addresses scanned: - + Datasheet: http://www.intersil.com/data/fn/fn6847.pdf + * Intersil / Zilker Labs ZL2006 + Prefix: 'zl2006' + Addresses scanned: - + Datasheet: http://www.intersil.com/data/fn/fn6850.pdf + * Intersil / Zilker Labs ZL2008 + Prefix: 'zl2008' + Addresses scanned: - + Datasheet: http://www.intersil.com/data/fn/fn6859.pdf + * Intersil / Zilker Labs ZL2105 + Prefix: 'zl2105' + Addresses scanned: - + Datasheet: http://www.intersil.com/data/fn/fn6851.pdf + * Intersil / Zilker Labs ZL2106 + Prefix: 'zl2106' + Addresses scanned: - + Datasheet: http://www.intersil.com/data/fn/fn6852.pdf + * Intersil / Zilker Labs ZL6100 + Prefix: 'zl6100' + Addresses scanned: - + Datasheet: http://www.intersil.com/data/fn/fn6876.pdf + * Intersil / Zilker Labs ZL6105 + Prefix: 'zl6105' + Addresses scanned: - + Datasheet: http://www.intersil.com/data/fn/fn6906.pdf + +Author: Guenter Roeck <guenter.roeck@ericsson.com> + + +Description +----------- + +This driver supports hardware montoring for Intersil / Zilker Labs ZL6100 and +compatible digital DC-DC controllers. + +The driver is a client driver to the core PMBus driver. Please see +Documentation/hwmon/pmbus and Documentation.hwmon/pmbus-core for details +on PMBus client drivers. + + +Usage Notes +----------- + +This driver does not auto-detect devices. You will have to instantiate the +devices explicitly. Please see Documentation/i2c/instantiating-devices for +details. + +WARNING: Do not access chip registers using the i2cdump command, and do not use +any of the i2ctools commands on a command register used to save and restore +configuration data (0x11, 0x12, 0x15, 0x16, and 0xf4). The chips supported by +this driver interpret any access to those command registers (including read +commands) as request to execute the command in question. Unless write accesses +to those registers are protected, this may result in power loss, board resets, +and/or Flash corruption. Worst case, your board may turn into a brick. + + +Platform data support +--------------------- + +The driver supports standard PMBus driver platform data. + + +Module parameters +----------------- + +delay +----- + +Some Intersil/Zilker Labs DC-DC controllers require a minimum interval between +I2C bus accesses. According to Intersil, the minimum interval is 2 ms, though +1 ms appears to be sufficient and has not caused any problems in testing. +The problem is known to affect ZL6100, ZL2105, and ZL2008. It is known not to +affect ZL2004 and ZL6105. The driver automatically sets the interval to 1 ms +except for ZL2004 and ZL6105. To enable manual override, the driver provides a +writeable module parameter, 'delay', which can be used to set the interval to +a value between 0 and 65,535 microseconds. + + +Sysfs entries +------------- + +The following attributes are supported. Limits are read-write; all other +attributes are read-only. + +in1_label "vin" +in1_input Measured input voltage. +in1_min Minimum input voltage. +in1_max Maximum input voltage. +in1_lcrit Critical minumum input voltage. +in1_crit Critical maximum input voltage. +in1_min_alarm Input voltage low alarm. +in1_max_alarm Input voltage high alarm. +in1_lcrit_alarm Input voltage critical low alarm. +in1_crit_alarm Input voltage critical high alarm. + +in2_label "vout1" +in2_input Measured output voltage. +in2_lcrit Critical minumum output Voltage. +in2_crit Critical maximum output voltage. +in2_lcrit_alarm Critical output voltage critical low alarm. +in2_crit_alarm Critical output voltage critical high alarm. + +curr1_label "iout1" +curr1_input Measured output current. +curr1_lcrit Critical minimum output current. +curr1_crit Critical maximum output current. +curr1_lcrit_alarm Output current critical low alarm. +curr1_crit_alarm Output current critical high alarm. + +temp[12]_input Measured temperature. +temp[12]_min Minimum temperature. +temp[12]_max Maximum temperature. +temp[12]_lcrit Critical low temperature. +temp[12]_crit Critical high temperature. +temp[12]_min_alarm Chip temperature low alarm. +temp[12]_max_alarm Chip temperature high alarm. +temp[12]_lcrit_alarm Chip temperature critical low alarm. +temp[12]_crit_alarm Chip temperature critical high alarm. diff --git a/Documentation/input/input.txt b/Documentation/input/input.txt index b93c08442e3..b3d6787b4fb 100644 --- a/Documentation/input/input.txt +++ b/Documentation/input/input.txt @@ -111,7 +111,7 @@ LCDs and many other purposes. The monitor and speaker controls should be easy to add to the hid/input interface, but for the UPSs and LCDs it doesn't make much sense. For this, -the hiddev interface was designed. See Documentation/usb/hiddev.txt +the hiddev interface was designed. See Documentation/hid/hiddev.txt for more information about it. The usage of the usbhid module is very simple, it takes no parameters, diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt index 845a191004b..54078ed96b3 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt @@ -319,4 +319,6 @@ Code Seq#(hex) Include File Comments <mailto:thomas@winischhofer.net> 0xF4 00-1F video/mbxfb.h mbxfb <mailto:raph@8d.com> +0xF6 all LTTng Linux Trace Toolkit Next Generation + <mailto:mathieu.desnoyers@efficios.com> 0xFD all linux/dm-ioctl.h diff --git a/Documentation/kernel-docs.txt b/Documentation/kernel-docs.txt index 0e0734b509d..eda1eb1451a 100644 --- a/Documentation/kernel-docs.txt +++ b/Documentation/kernel-docs.txt @@ -300,7 +300,7 @@ * Title: "The Kernel Hacking HOWTO" Author: Various Talented People, and Rusty. - Location: in kernel tree, Documentation/DocBook/kernel-hacking/ + Location: in kernel tree, Documentation/DocBook/kernel-hacking.tmpl (must be built as "make {htmldocs | psdocs | pdfdocs}) Keywords: HOWTO, kernel contexts, deadlock, locking, modules, symbols, return conventions. @@ -351,7 +351,7 @@ * Title: "Linux Kernel Locking HOWTO" Author: Various Talented People, and Rusty. - Location: in kernel tree, Documentation/DocBook/kernel-locking/ + Location: in kernel tree, Documentation/DocBook/kernel-locking.tmpl (must be built as "make {htmldocs | psdocs | pdfdocs}) Keywords: locks, locking, spinlock, semaphore, atomic, race condition, bottom halves, tasklets, softirqs. diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 6ca1f5cb71e..a8ba119a4d5 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -49,6 +49,7 @@ parameter is applicable: EDD BIOS Enhanced Disk Drive Services (EDD) is enabled EFI EFI Partitioning (GPT) is enabled EIDE EIDE/ATAPI support is enabled. + EVM Extended Verification Module FB The frame buffer device is enabled. FTRACE Function tracing enabled. GCOV GCOV profiling is enabled. @@ -163,7 +164,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. rsdt -- prefer RSDT over (default) XSDT copy_dsdt -- copy DSDT to memory - See also Documentation/power/pm.txt, pci=noacpi + See also Documentation/power/runtime_pm.txt, pci=noacpi acpi_rsdp= [ACPI,EFI,KEXEC] Pass the RSDP address to the kernel, mostly used @@ -319,7 +320,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. amijoy.map= [HW,JOY] Amiga joystick support Map of devices attached to JOY0DAT and JOY1DAT Format: <a>,<b> - See also Documentation/kernel/input/joystick.txt + See also Documentation/input/joystick.txt analog.map= [HW,JOY] Analog joystick and gamepad support Specifies type or capabilities of an analog joystick @@ -408,7 +409,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. bttv.radio= Most important insmod options are available as kernel args too. bttv.pll= See Documentation/video4linux/bttv/Insmod-options - bttv.tuner= and Documentation/video4linux/bttv/CARDLIST + bttv.tuner= bulk_remove=off [PPC] This parameter disables the use of the pSeries firmware feature for flushing multiple hpte entries @@ -724,7 +725,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. elevator= [IOSCHED] Format: {"cfq" | "deadline" | "noop"} - See Documentation/block/as-iosched.txt and + See Documentation/block/cfq-iosched.txt and Documentation/block/deadline-iosched.txt for details. elfcorehdr= [IA-64,PPC,SH,X86] @@ -760,12 +761,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted. This option is obsoleted by the "netdev=" option, which has equivalent usage. See its documentation for details. + evm= [EVM] + Format: { "fix" } + Permit 'security.evm' to be updated regardless of + current integrity status. + failslab= fail_page_alloc= fail_make_request=[KNL] General fault injection mechanism. Format: <interval>,<probability>,<space>,<times> - See also /Documentation/fault-injection/. + See also Documentation/fault-injection/. floppy= [HW] See Documentation/blockdev/floppy.txt. @@ -1014,10 +1020,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. has the capability. With this option, super page will not be supported. intremap= [X86-64, Intel-IOMMU] - Format: { on (default) | off | nosid } on enable Interrupt Remapping (default) off disable Interrupt Remapping nosid disable Source ID checking + no_x2apic_optout + BIOS x2APIC opt-out request will be ignored inttest= [IA-64] @@ -1350,9 +1357,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. it is equivalent to "nosmp", which also disables the IO APIC. - max_loop= [LOOP] Maximum number of loopback devices that can - be mounted - Format: <1-256> + max_loop= [LOOP] The number of loop block devices that get + (loop.max_loop) unconditionally pre-created at init time. The default + number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead + of statically allocating a predefined number, loop + devices can be requested on-demand with the + /dev/loop-control interface. mcatest= [IA-64] @@ -2083,9 +2093,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Override pmtimer IOPort with a hex value. e.g. pmtmr=0x508 - pnp.debug [PNP] - Enable PNP debug messages. This depends on the - CONFIG_PNP_DEBUG_MESSAGES option. + pnp.debug=1 [PNP] + Enable PNP debug messages (depends on the + CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time + via /sys/module/pnp/parameters/debug. We always show + current resource usage; turning this on also shows + possible settings and some assignment information. pnpacpi= [ACPI] { off } @@ -2234,6 +2247,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. in <PAGE_SIZE> units (needed only for swap files). See Documentation/power/swsusp-and-swap-files.txt + resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to + read the resume files + + resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up. + Useful for devices that are detected asynchronously + (e.g. USB and MMC devices). + hibernate= [HIBERNATION] noresume Don't check if there's a hibernation image present during boot. @@ -2369,7 +2389,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Format: <integer> sonypi.*= [HW] Sony Programmable I/O Control Device driver - See Documentation/sonypi.txt + See Documentation/laptops/sonypi.txt specialix= [HW,SERIAL] Specialix multi-serial port adapter See Documentation/serial/specialix.txt. @@ -2700,10 +2720,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. functions are at fixed addresses, they make nice targets for exploits that can control RIP. - emulate [default] Vsyscalls turn into traps and are - emulated reasonably safely. + emulate Vsyscalls turn into traps and are emulated + reasonably safely. - native Vsyscalls are native syscall instructions. + native [default] Vsyscalls are native syscall + instructions. This is a little bit faster than trapping and makes a few dynamic recompilers work better than they would in emulation mode. diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt index 61815483efa..3ff0dad62d3 100644 --- a/Documentation/laptops/thinkpad-acpi.txt +++ b/Documentation/laptops/thinkpad-acpi.txt @@ -736,7 +736,7 @@ status as "unknown". The available commands are: sysfs notes: The ThinkLight sysfs interface is documented by the LED class -documentation, in Documentation/leds-class.txt. The ThinkLight LED name +documentation, in Documentation/leds/leds-class.txt. The ThinkLight LED name is "tpacpi::thinklight". Due to limitations in the sysfs LED class, if the status of the ThinkLight @@ -833,7 +833,7 @@ All of the above can be turned on and off and can be made to blink. sysfs notes: The ThinkPad LED sysfs interface is described in detail by the LED class -documentation, in Documentation/leds-class.txt. +documentation, in Documentation/leds/leds-class.txt. The LEDs are named (in LED ID order, from 0 to 12): "tpacpi::power", "tpacpi:orange:batt", "tpacpi:green:batt", diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt index 669b5fb03a8..3a0f879533c 100644 --- a/Documentation/media-framework.txt +++ b/Documentation/media-framework.txt @@ -9,8 +9,8 @@ Introduction ------------ The media controller API is documented in DocBook format in -Documentation/DocBook/v4l/media-controller.xml. This document will focus on -the kernel-side implementation of the media framework. +Documentation/DocBook/media/v4l/media-controller.xml. This document will focus +on the kernel-side implementation of the media framework. Abstract media device model diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index f0d3a8026a5..2759f7c188f 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -438,7 +438,7 @@ There are certain things that the Linux kernel memory barriers do not guarantee: [*] For information on bus mastering DMA and coherency please read: Documentation/PCI/pci.txt - Documentation/PCI/PCI-DMA-mapping.txt + Documentation/DMA-API-HOWTO.txt Documentation/DMA-API.txt diff --git a/Documentation/networking/00-INDEX b/Documentation/networking/00-INDEX index 4edd78dfb36..bbce1215434 100644 --- a/Documentation/networking/00-INDEX +++ b/Documentation/networking/00-INDEX @@ -1,13 +1,21 @@ 00-INDEX - this file +3c359.txt + - information on the 3Com TokenLink Velocity XL (3c5359) driver. 3c505.txt - information on the 3Com EtherLink Plus (3c505) driver. +3c509.txt + - information on the 3Com Etherlink III Series Ethernet cards. 6pack.txt - info on the 6pack protocol, an alternative to KISS for AX.25 DLINK.txt - info on the D-Link DE-600/DE-620 parallel port pocket adapters PLIP.txt - PLIP: The Parallel Line Internet Protocol device driver +README.ipw2100 + - README for the Intel PRO/Wireless 2100 driver. +README.ipw2200 + - README for the Intel PRO/Wireless 2915ABG and 2200BG driver. README.sb1000 - info on General Instrument/NextLevel SURFboard1000 cable modem. alias.txt @@ -20,8 +28,12 @@ atm.txt - info on where to get ATM programs and support for Linux. ax25.txt - info on using AX.25 and NET/ROM code for Linux +batman-adv.txt + - B.A.T.M.A.N routing protocol on top of layer 2 Ethernet Frames. baycom.txt - info on the driver for Baycom style amateur radio modems +bonding.txt + - Linux Ethernet Bonding Driver HOWTO: link aggregation in Linux. bridge.txt - where to get user space programs for ethernet bridging with Linux. can.txt @@ -34,32 +46,60 @@ cxacru.txt - Conexant AccessRunner USB ADSL Modem cxacru-cf.py - Conexant AccessRunner USB ADSL Modem configuration file parser +cxgb.txt + - Release Notes for the Chelsio N210 Linux device driver. +dccp.txt + - the Datagram Congestion Control Protocol (DCCP) (RFC 4340..42). de4x5.txt - the Digital EtherWORKS DE4?? and DE5?? PCI Ethernet driver decnet.txt - info on using the DECnet networking layer in Linux. depca.txt - the Digital DEPCA/EtherWORKS DE1?? and DE2?? LANCE Ethernet driver +dl2k.txt + - README for D-Link DL2000-based Gigabit Ethernet Adapters (dl2k.ko). +dm9000.txt + - README for the Simtec DM9000 Network driver. dmfe.txt - info on the Davicom DM9102(A)/DM9132/DM9801 fast ethernet driver. +dns_resolver.txt + - The DNS resolver module allows kernel servies to make DNS queries. +driver.txt + - Softnet driver issues. e100.txt - info on Intel's EtherExpress PRO/100 line of 10/100 boards e1000.txt - info on Intel's E1000 line of gigabit ethernet boards +e1000e.txt + - README for the Intel Gigabit Ethernet Driver (e1000e). eql.txt - serial IP load balancing ewrk3.txt - the Digital EtherWORKS 3 DE203/4/5 Ethernet driver +fib_trie.txt + - Level Compressed Trie (LC-trie) notes: a structure for routing. filter.txt - Linux Socket Filtering fore200e.txt - FORE Systems PCA-200E/SBA-200E ATM NIC driver info. framerelay.txt - info on using Frame Relay/Data Link Connection Identifier (DLCI). +gen_stats.txt + - Generic networking statistics for netlink users. +generic_hdlc.txt + - The generic High Level Data Link Control (HDLC) layer. generic_netlink.txt - info on Generic Netlink +gianfar.txt + - Gianfar Ethernet Driver. ieee802154.txt - Linux IEEE 802.15.4 implementation, API and drivers +ifenslave.c + - Configure network interfaces for parallel routing (bonding). +igb.txt + - README for the Intel Gigabit Ethernet Driver (igb). +igbvf.txt + - README for the Intel Gigabit Ethernet Driver (igbvf). ip-sysctl.txt - /proc/sys/net/ipv4/* variables ip_dynaddr.txt @@ -68,41 +108,117 @@ ipddp.txt - AppleTalk-IP Decapsulation and AppleTalk-IP Encapsulation iphase.txt - Interphase PCI ATM (i)Chip IA Linux driver info. +ipv6.txt + - Options to the ipv6 kernel module. +ipvs-sysctl.txt + - Per-inode explanation of the /proc/sys/net/ipv4/vs interface. irda.txt - where to get IrDA (infrared) utilities and info for Linux. +ixgb.txt + - README for the Intel 10 Gigabit Ethernet Driver (ixgb). +ixgbe.txt + - README for the Intel 10 Gigabit Ethernet Driver (ixgbe). +ixgbevf.txt + - README for the Intel Virtual Function (VF) Driver (ixgbevf). +l2tp.txt + - User guide to the L2TP tunnel protocol. lapb-module.txt - programming information of the LAPB module. ltpc.txt - the Apple or Farallon LocalTalk PC card driver +mac80211-injection.txt + - HOWTO use packet injection with mac80211 multicast.txt - Behaviour of cards under Multicast +multiqueue.txt + - HOWTO for multiqueue network device support. +netconsole.txt + - The network console module netconsole.ko: configuration and notes. +netdev-features.txt + - Network interface features API description. netdevices.txt - info on network device driver functions exported to the kernel. +netif-msg.txt + - Design of the network interface message level setting (NETIF_MSG_*). +nfc.txt + - The Linux Near Field Communication (NFS) subsystem. olympic.txt - IBM PCI Pit/Pit-Phy/Olympic Token Ring driver info. +operstates.txt + - Overview of network interface operational states. +packet_mmap.txt + - User guide to memory mapped packet socket rings (PACKET_[RT]X_RING). +phonet.txt + - The Phonet packet protocol used in Nokia cellular modems. +phy.txt + - The PHY abstraction layer. +pktgen.txt + - User guide to the kernel packet generator (pktgen.ko). policy-routing.txt - IP policy-based routing +ppp_generic.txt + - Information about the generic PPP driver. +proc_net_tcp.txt + - Per inode overview of the /proc/net/tcp and /proc/net/tcp6 interfaces. +radiotap-headers.txt + - Background on radiotap headers. ray_cs.txt - Raylink Wireless LAN card driver info. +rds.txt + - Background on the reliable, ordered datagram delivery method RDS. +regulatory.txt + - Overview of the Linux wireless regulatory infrastructure. +rxrpc.txt + - Guide to the RxRPC protocol. +s2io.txt + - Release notes for Neterion Xframe I/II 10GbE driver. +scaling.txt + - Explanation of network scaling techniques: RSS, RPS, RFS, aRFS, XPS. +sctp.txt + - Notes on the Linux kernel implementation of the SCTP protocol. +secid.txt + - Explanation of the secid member in flow structures. skfp.txt - SysKonnect FDDI (SK-5xxx, Compaq Netelligent) driver info. smc9.txt - the driver for SMC's 9000 series of Ethernet cards smctr.txt - SMC TokenCard TokenRing Linux driver info. +spider-net.txt + - README for the Spidernet Driver (as found in PS3 / Cell BE). +stmmac.txt + - README for the STMicro Synopsys Ethernet driver. +tc-actions-env-rules.txt + - rules for traffic control (tc) actions. +timestamping.txt + - overview of network packet timestamping variants. tcp.txt - short blurb on how TCP output takes place. +tcp-thin.txt + - kernel tuning options for low rate 'thin' TCP streams. tlan.txt - ThunderLAN (Compaq Netelligent 10/100, Olicom OC-2xxx) driver info. tms380tr.txt - SysKonnect Token Ring ISA/PCI adapter driver info. +tproxy.txt + - Transparent proxy support user guide. tuntap.txt - TUN/TAP device driver, allowing user space Rx/Tx of packets. +udplite.txt + - UDP-Lite protocol (RFC 3828) introduction. vortex.txt - info on using 3Com Vortex (3c590, 3c592, 3c595, 3c597) Ethernet cards. +vxge.txt + - README for the Neterion X3100 PCIe Server Adapter. x25.txt - general info on X.25 development. x25-iface.txt - description of the X.25 Packet Layer to LAPB device interface. +xfrm_proc.txt + - description of the statistics package for XFRM. +xfrm_sync.txt + - sync patches for XFRM enable migration of an SA between hosts. +xfrm_sysctl.txt + - description of the XFRM configuration options. z8530drv.txt - info about Linux driver for Z8530 based HDLC cards for AX.25 diff --git a/Documentation/networking/batman-adv.txt b/Documentation/networking/batman-adv.txt index 88d4afbdef9..c86d03f18a5 100644 --- a/Documentation/networking/batman-adv.txt +++ b/Documentation/networking/batman-adv.txt @@ -1,4 +1,4 @@ -[state: 17-04-2011] +[state: 21-08-2011] BATMAN-ADV ---------- @@ -68,9 +68,9 @@ All mesh wide settings can be found in batman's own interface folder: # ls /sys/class/net/bat0/mesh/ -# aggregated_ogms gw_bandwidth hop_penalty -# bonding gw_mode orig_interval -# fragmentation gw_sel_class vis_mode +# aggregated_ogms fragmentation gw_sel_class vis_mode +# ap_isolation gw_bandwidth hop_penalty +# bonding gw_mode orig_interval There is a special folder for debugging information: diff --git a/Documentation/networking/dmfe.txt b/Documentation/networking/dmfe.txt index 8006c227fda..25320bf19c8 100644 --- a/Documentation/networking/dmfe.txt +++ b/Documentation/networking/dmfe.txt @@ -1,3 +1,5 @@ +Note: This driver doesn't have a maintainer. + Davicom DM9102(A)/DM9132/DM9801 fast ethernet driver for Linux. This program is free software; you can redistribute it and/or @@ -55,7 +57,6 @@ Test and make sure PCI latency is now correct for all cases. Authors: Sten Wang <sten_wang@davicom.com.tw > : Original Author -Tobias Ringstrom <tori@unhappy.mine.nu> : Current Maintainer Contributors: diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index db2a4067013..cb7f3148035 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -992,7 +992,7 @@ bindv6only - BOOLEAN TRUE: disable IPv4-mapped address feature FALSE: enable IPv4-mapped address feature - Default: FALSE (as specified in RFC2553bis) + Default: FALSE (as specified in RFC3493) IPv6 Fragmentation: @@ -1042,9 +1042,14 @@ conf/interface/*: The functional behaviour for certain settings is different depending on whether local forwarding is enabled or not. -accept_ra - BOOLEAN +accept_ra - INTEGER Accept Router Advertisements; autoconfigure using them. + It also determines whether or not to transmit Router + Solicitations. If and only if the functional setting is to + accept Router Advertisements, Router Solicitations will be + transmitted. + Possible values are: 0 Do not accept Router Advertisements. 1 Accept Router Advertisements if forwarding is disabled. @@ -1106,7 +1111,7 @@ dad_transmits - INTEGER The amount of Duplicate Address Detection probes to send. Default: 1 -forwarding - BOOLEAN +forwarding - INTEGER Configure interface-specific Host/Router behaviour. Note: It is recommended to have the same setting on all @@ -1115,14 +1120,14 @@ forwarding - BOOLEAN Possible values are: 0 Forwarding disabled 1 Forwarding enabled - 2 Forwarding enabled (Hybrid Mode) FALSE (0): By default, Host behaviour is assumed. This means: 1. IsRouter flag is not set in Neighbour Advertisements. - 2. Router Solicitations are being sent when necessary. + 2. If accept_ra is TRUE (default), transmit Router + Solicitations. 3. If accept_ra is TRUE (default), accept Router Advertisements (and do autoconfiguration). 4. If accept_redirects is TRUE (default), accept Redirects. @@ -1133,16 +1138,10 @@ forwarding - BOOLEAN This means exactly the reverse from the above: 1. IsRouter flag is set in Neighbour Advertisements. - 2. Router Solicitations are not sent. + 2. Router Solicitations are not sent unless accept_ra is 2. 3. Router Advertisements are ignored unless accept_ra is 2. 4. Redirects are ignored. - TRUE (2): - - Hybrid mode. Same behaviour as TRUE, except for: - - 2. Router Solicitations are being sent when necessary. - Default: 0 (disabled) if global forwarding is disabled (default), otherwise 1 (enabled). diff --git a/Documentation/networking/mac80211-injection.txt b/Documentation/networking/mac80211-injection.txt index b30e81ad530..3a930072b16 100644 --- a/Documentation/networking/mac80211-injection.txt +++ b/Documentation/networking/mac80211-injection.txt @@ -23,6 +23,10 @@ radiotap headers and used to control injection: IEEE80211_RADIOTAP_F_FRAG: frame will be fragmented if longer than the current fragmentation threshold. + * IEEE80211_RADIOTAP_TX_FLAGS + + IEEE80211_RADIOTAP_F_TX_NOACK: frame should be sent without waiting for + an ACK even if it is a unicast frame The injection code can also skip all other currently defined radiotap fields facilitating replay of captured radiotap headers directly. diff --git a/Documentation/networking/netdevices.txt b/Documentation/networking/netdevices.txt index 87b3d15f523..89358341682 100644 --- a/Documentation/networking/netdevices.txt +++ b/Documentation/networking/netdevices.txt @@ -73,7 +73,7 @@ dev->hard_start_xmit: has to lock by itself when needed. It is recommended to use a try lock for this and return NETDEV_TX_LOCKED when the spin lock fails. The locking there should also properly protect against - set_multicast_list. Note that the use of NETIF_F_LLTX is deprecated. + set_rx_mode. Note that the use of NETIF_F_LLTX is deprecated. Don't use it for new drivers. Context: Process with BHs disabled or BH (timer), @@ -92,7 +92,7 @@ dev->tx_timeout: Context: BHs disabled Notes: netif_queue_stopped() is guaranteed true -dev->set_multicast_list: +dev->set_rx_mode: Synchronization: netif_tx_lock spinlock. Context: BHs disabled diff --git a/Documentation/networking/scaling.txt b/Documentation/networking/scaling.txt index 7254b4b5910..a177de21d28 100644 --- a/Documentation/networking/scaling.txt +++ b/Documentation/networking/scaling.txt @@ -27,7 +27,7 @@ applying a filter to each packet that assigns it to one of a small number of logical flows. Packets for each flow are steered to a separate receive queue, which in turn can be processed by separate CPUs. This mechanism is generally known as “Receive-side Scaling” (RSS). The goal of RSS and -the other scaling techniques to increase performance uniformly. +the other scaling techniques is to increase performance uniformly. Multi-queue distribution can also be used for traffic prioritization, but that is not the focus of these techniques. @@ -52,7 +52,8 @@ module parameter for specifying the number of hardware queues to configure. In the bnx2x driver, for instance, this parameter is called num_queues. A typical RSS configuration would be to have one receive queue for each CPU if the device supports enough queues, or otherwise at least -one for each cache domain at a particular cache level (L1, L2, etc.). +one for each memory domain, where a memory domain is a set of CPUs that +share a particular memory level (L1, L2, NUMA node, etc.). The indirection table of an RSS device, which resolves a queue by masked hash, is usually programmed by the driver at initialization. The @@ -72,7 +73,7 @@ of queues to IRQs can be determined from /proc/interrupts. By default, an IRQ may be handled on any CPU. Because a non-negligible part of packet processing takes place in receive interrupt handling, it is advantageous to spread receive interrupts between CPUs. To manually adjust the IRQ -affinity of each interrupt see Documentation/IRQ-affinity. Some systems +affinity of each interrupt see Documentation/IRQ-affinity.txt. Some systems will be running irqbalance, a daemon that dynamically optimizes IRQ assignments and as a result may override any manual settings. @@ -82,11 +83,17 @@ RSS should be enabled when latency is a concern or whenever receive interrupt processing forms a bottleneck. Spreading load between CPUs decreases queue length. For low latency networking, the optimal setting is to allocate as many queues as there are CPUs in the system (or the -NIC maximum, if lower). Because the aggregate number of interrupts grows -with each additional queue, the most efficient high-rate configuration +NIC maximum, if lower). The most efficient high-rate configuration is likely the one with the smallest number of receive queues where no -CPU that processes receive interrupts reaches 100% utilization. Per-cpu -load can be observed using the mpstat utility. +receive queue overflows due to a saturated CPU, because in default +mode with interrupt coalescing enabled, the aggregate number of +interrupts (and thus work) grows with each additional queue. + +Per-cpu load can be observed using the mpstat utility, but note that on +processors with hyperthreading (HT), each hyperthread is represented as +a separate CPU. For interrupt handling, HT has shown no benefit in +initial tests, so limit the number of queues to the number of CPU cores +in the system. RPS: Receive Packet Steering @@ -145,7 +152,7 @@ the bitmap. == Suggested Configuration For a single queue device, a typical RPS configuration would be to set -the rps_cpus to the CPUs in the same cache domain of the interrupting +the rps_cpus to the CPUs in the same memory domain of the interrupting CPU. If NUMA locality is not an issue, this could also be all CPUs in the system. At high interrupt rate, it might be wise to exclude the interrupting CPU from the map since that already performs much work. @@ -154,7 +161,7 @@ For a multi-queue system, if RSS is configured so that a hardware receive queue is mapped to each CPU, then RPS is probably redundant and unnecessary. If there are fewer hardware queues than CPUs, then RPS might be beneficial if the rps_cpus for each queue are the ones that -share the same cache domain as the interrupting CPU for that queue. +share the same memory domain as the interrupting CPU for that queue. RFS: Receive Flow Steering @@ -179,10 +186,10 @@ are steered using plain RPS. Multiple table entries may point to the same CPU. Indeed, with many flows and few CPUs, it is very likely that a single application thread handles flows with many different flow hashes. -rps_sock_table is a global flow table that contains the *desired* CPU for -flows: the CPU that is currently processing the flow in userspace. Each -table value is a CPU index that is updated during calls to recvmsg and -sendmsg (specifically, inet_recvmsg(), inet_sendmsg(), inet_sendpage() +rps_sock_flow_table is a global flow table that contains the *desired* CPU +for flows: the CPU that is currently processing the flow in userspace. +Each table value is a CPU index that is updated during calls to recvmsg +and sendmsg (specifically, inet_recvmsg(), inet_sendmsg(), inet_sendpage() and tcp_splice_read()). When the scheduler moves a thread to a new CPU while it has outstanding @@ -236,7 +243,7 @@ configured. The number of entries in the global flow table is set through: The number of entries in the per-queue flow table are set through: - /sys/class/net/<dev>/queues/tx-<n>/rps_flow_cnt + /sys/class/net/<dev>/queues/rx-<n>/rps_flow_cnt == Suggested Configuration @@ -326,7 +333,7 @@ The queue chosen for transmitting a particular flow is saved in the corresponding socket structure for the flow (e.g. a TCP connection). This transmit queue is used for subsequent packets sent on the flow to prevent out of order (ooo) packets. The choice also amortizes the cost -of calling get_xps_queues() over all packets in the connection. To avoid +of calling get_xps_queues() over all packets in the flow. To avoid ooo packets, the queue for a flow can subsequently only be changed if skb->ooo_okay is set for a packet in the flow. This flag indicates that there are no outstanding packets in the flow, so the transmit queue can diff --git a/Documentation/networking/stmmac.txt b/Documentation/networking/stmmac.txt index 57a24108b84..8d67980fabe 100644 --- a/Documentation/networking/stmmac.txt +++ b/Documentation/networking/stmmac.txt @@ -76,7 +76,16 @@ core. 4.5) DMA descriptors Driver handles both normal and enhanced descriptors. The latter has been only -tested on DWC Ether MAC 10/100/1000 Universal version 3.41a. +tested on DWC Ether MAC 10/100/1000 Universal version 3.41a and later. + +STMMAC supports DMA descriptor to operate both in dual buffer (RING) +and linked-list(CHAINED) mode. In RING each descriptor points to two +data buffer pointers whereas in CHAINED mode they point to only one data +buffer pointer. RING mode is the default. + +In CHAINED mode each descriptor will have pointer to next descriptor in +the list, hence creating the explicit chaining in the descriptor itself, +whereas such explicit chaining is not possible in RING mode. 4.6) Ethtool support Ethtool is supported. Driver statistics and internal errors can be taken using: @@ -235,7 +244,38 @@ reset procedure etc). o enh_desc.c: functions for handling enhanced descriptors o norm_desc.c: functions for handling normal descriptors -5) TODO: +5) Debug Information + +The driver exports many information i.e. internal statistics, +debug information, MAC and DMA registers etc. + +These can be read in several ways depending on the +type of the information actually needed. + +For example a user can be use the ethtool support +to get statistics: e.g. using: ethtool -S ethX +(that shows the Management counters (MMC) if supported) +or sees the MAC/DMA registers: e.g. using: ethtool -d ethX + +Compiling the Kernel with CONFIG_DEBUG_FS and enabling the +STMMAC_DEBUG_FS option the driver will export the following +debugfs entries: + +/sys/kernel/debug/stmmaceth/descriptors_status + To show the DMA TX/RX descriptor rings + +Developer can also use the "debug" module parameter to get +further debug information. + +In the end, there are other macros (that cannot be enabled +via menuconfig) to turn-on the RX/TX DMA debugging, +specific MAC core debug printk etc. Others to enable the +debug in the TX and RX processes. +All these are only useful during the developing stage +and should never enabled inside the code for general usage. +In fact, these can generate an huge amount of debug messages. + +6) TODO: o XGMAC is not supported. o Review the timer optimisation code to use an embedded device that will be available in new chip generations. diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt new file mode 100644 index 00000000000..b04cb7d45a1 --- /dev/null +++ b/Documentation/pinctrl.txt @@ -0,0 +1,950 @@ +PINCTRL (PIN CONTROL) subsystem +This document outlines the pin control subsystem in Linux + +This subsystem deals with: + +- Enumerating and naming controllable pins + +- Multiplexing of pins, pads, fingers (etc) see below for details + +The intention is to also deal with: + +- Software-controlled biasing and driving mode specific pins, such as + pull-up/down, open drain etc, load capacitance configuration when controlled + by software, etc. + + +Top-level interface +=================== + +Definition of PIN CONTROLLER: + +- A pin controller is a piece of hardware, usually a set of registers, that + can control PINs. It may be able to multiplex, bias, set load capacitance, + set drive strength etc for individual pins or groups of pins. + +Definition of PIN: + +- PINS are equal to pads, fingers, balls or whatever packaging input or + output line you want to control and these are denoted by unsigned integers + in the range 0..maxpin. This numberspace is local to each PIN CONTROLLER, so + there may be several such number spaces in a system. This pin space may + be sparse - i.e. there may be gaps in the space with numbers where no + pin exists. + +When a PIN CONTROLLER is instatiated, it will register a descriptor to the +pin control framework, and this descriptor contains an array of pin descriptors +describing the pins handled by this specific pin controller. + +Here is an example of a PGA (Pin Grid Array) chip seen from underneath: + + A B C D E F G H + + 8 o o o o o o o o + + 7 o o o o o o o o + + 6 o o o o o o o o + + 5 o o o o o o o o + + 4 o o o o o o o o + + 3 o o o o o o o o + + 2 o o o o o o o o + + 1 o o o o o o o o + +To register a pin controller and name all the pins on this package we can do +this in our driver: + +#include <linux/pinctrl/pinctrl.h> + +const struct pinctrl_pin_desc __refdata foo_pins[] = { + PINCTRL_PIN(0, "A1"), + PINCTRL_PIN(1, "A2"), + PINCTRL_PIN(2, "A3"), + ... + PINCTRL_PIN(61, "H6"), + PINCTRL_PIN(62, "H7"), + PINCTRL_PIN(63, "H8"), +}; + +static struct pinctrl_desc foo_desc = { + .name = "foo", + .pins = foo_pins, + .npins = ARRAY_SIZE(foo_pins), + .maxpin = 63, + .owner = THIS_MODULE, +}; + +int __init foo_probe(void) +{ + struct pinctrl_dev *pctl; + + pctl = pinctrl_register(&foo_desc, <PARENT>, NULL); + if (IS_ERR(pctl)) + pr_err("could not register foo pin driver\n"); +} + +Pins usually have fancier names than this. You can find these in the dataheet +for your chip. Notice that the core pinctrl.h file provides a fancy macro +called PINCTRL_PIN() to create the struct entries. As you can see I enumerated +the pins from 0 in the upper left corner to 63 in the lower right corner, +this enumeration was arbitrarily chosen, in practice you need to think +through your numbering system so that it matches the layout of registers +and such things in your driver, or the code may become complicated. You must +also consider matching of offsets to the GPIO ranges that may be handled by +the pin controller. + +For a padring with 467 pads, as opposed to actual pins, I used an enumeration +like this, walking around the edge of the chip, which seems to be industry +standard too (all these pads had names, too): + + + 0 ..... 104 + 466 105 + . . + . . + 358 224 + 357 .... 225 + + +Pin groups +========== + +Many controllers need to deal with groups of pins, so the pin controller +subsystem has a mechanism for enumerating groups of pins and retrieving the +actual enumerated pins that are part of a certain group. + +For example, say that we have a group of pins dealing with an SPI interface +on { 0, 8, 16, 24 }, and a group of pins dealing with an I2C interface on pins +on { 24, 25 }. + +These two groups are presented to the pin control subsystem by implementing +some generic pinctrl_ops like this: + +#include <linux/pinctrl/pinctrl.h> + +struct foo_group { + const char *name; + const unsigned int *pins; + const unsigned num_pins; +}; + +static unsigned int spi0_pins[] = { 0, 8, 16, 24 }; +static unsigned int i2c0_pins[] = { 24, 25 }; + +static const struct foo_group foo_groups[] = { + { + .name = "spi0_grp", + .pins = spi0_pins, + .num_pins = ARRAY_SIZE(spi0_pins), + }, + { + .name = "i2c0_grp", + .pins = i2c0_pins, + .num_pins = ARRAY_SIZE(i2c0_pins), + }, +}; + + +static int foo_list_groups(struct pinctrl_dev *pctldev, unsigned selector) +{ + if (selector >= ARRAY_SIZE(foo_groups)) + return -EINVAL; + return 0; +} + +static const char *foo_get_group_name(struct pinctrl_dev *pctldev, + unsigned selector) +{ + return foo_groups[selector].name; +} + +static int foo_get_group_pins(struct pinctrl_dev *pctldev, unsigned selector, + unsigned ** const pins, + unsigned * const num_pins) +{ + *pins = (unsigned *) foo_groups[selector].pins; + *num_pins = foo_groups[selector].num_pins; + return 0; +} + +static struct pinctrl_ops foo_pctrl_ops = { + .list_groups = foo_list_groups, + .get_group_name = foo_get_group_name, + .get_group_pins = foo_get_group_pins, +}; + + +static struct pinctrl_desc foo_desc = { + ... + .pctlops = &foo_pctrl_ops, +}; + +The pin control subsystem will call the .list_groups() function repeatedly +beginning on 0 until it returns non-zero to determine legal selectors, then +it will call the other functions to retrieve the name and pins of the group. +Maintaining the data structure of the groups is up to the driver, this is +just a simple example - in practice you may need more entries in your group +structure, for example specific register ranges associated with each group +and so on. + + +Interaction with the GPIO subsystem +=================================== + +The GPIO drivers may want to perform operations of various types on the same +physical pins that are also registered as pin controller pins. + +Since the pin controller subsystem have its pinspace local to the pin +controller we need a mapping so that the pin control subsystem can figure out +which pin controller handles control of a certain GPIO pin. Since a single +pin controller may be muxing several GPIO ranges (typically SoCs that have +one set of pins but internally several GPIO silicon blocks, each modeled as +a struct gpio_chip) any number of GPIO ranges can be added to a pin controller +instance like this: + +struct gpio_chip chip_a; +struct gpio_chip chip_b; + +static struct pinctrl_gpio_range gpio_range_a = { + .name = "chip a", + .id = 0, + .base = 32, + .npins = 16, + .gc = &chip_a; +}; + +static struct pinctrl_gpio_range gpio_range_a = { + .name = "chip b", + .id = 0, + .base = 48, + .npins = 8, + .gc = &chip_b; +}; + + +{ + struct pinctrl_dev *pctl; + ... + pinctrl_add_gpio_range(pctl, &gpio_range_a); + pinctrl_add_gpio_range(pctl, &gpio_range_b); +} + +So this complex system has one pin controller handling two different +GPIO chips. Chip a has 16 pins and chip b has 8 pins. They are mapped in +the global GPIO pin space at: + +chip a: [32 .. 47] +chip b: [48 .. 55] + +When GPIO-specific functions in the pin control subsystem are called, these +ranges will be used to look up the apropriate pin controller by inspecting +and matching the pin to the pin ranges across all controllers. When a +pin controller handling the matching range is found, GPIO-specific functions +will be called on that specific pin controller. + +For all functionalities dealing with pin biasing, pin muxing etc, the pin +controller subsystem will subtract the range's .base offset from the passed +in gpio pin number, and pass that on to the pin control driver, so the driver +will get an offset into its handled number range. Further it is also passed +the range ID value, so that the pin controller knows which range it should +deal with. + +For example: if a user issues pinctrl_gpio_set_foo(50), the pin control +subsystem will find that the second range on this pin controller matches, +subtract the base 48 and call the +pinctrl_driver_gpio_set_foo(pinctrl, range, 2) where the latter function has +this signature: + +int pinctrl_driver_gpio_set_foo(struct pinctrl_dev *pctldev, + struct pinctrl_gpio_range *rangeid, + unsigned offset); + +Now the driver knows that we want to do some GPIO-specific operation on the +second GPIO range handled by "chip b", at offset 2 in that specific range. + +(If the GPIO subsystem is ever refactored to use a local per-GPIO controller +pin space, this mapping will need to be augmented accordingly.) + + +PINMUX interfaces +================= + +These calls use the pinmux_* naming prefix. No other calls should use that +prefix. + + +What is pinmuxing? +================== + +PINMUX, also known as padmux, ballmux, alternate functions or mission modes +is a way for chip vendors producing some kind of electrical packages to use +a certain physical pin (ball, pad, finger, etc) for multiple mutually exclusive +functions, depending on the application. By "application" in this context +we usually mean a way of soldering or wiring the package into an electronic +system, even though the framework makes it possible to also change the function +at runtime. + +Here is an example of a PGA (Pin Grid Array) chip seen from underneath: + + A B C D E F G H + +---+ + 8 | o | o o o o o o o + | | + 7 | o | o o o o o o o + | | + 6 | o | o o o o o o o + +---+---+ + 5 | o | o | o o o o o o + +---+---+ +---+ + 4 o o o o o o | o | o + | | + 3 o o o o o o | o | o + | | + 2 o o o o o o | o | o + +-------+-------+-------+---+---+ + 1 | o o | o o | o o | o | o | + +-------+-------+-------+---+---+ + +This is not tetris. The game to think of is chess. Not all PGA/BGA packages +are chessboard-like, big ones have "holes" in some arrangement according to +different design patterns, but we're using this as a simple example. Of the +pins you see some will be taken by things like a few VCC and GND to feed power +to the chip, and quite a few will be taken by large ports like an external +memory interface. The remaining pins will often be subject to pin multiplexing. + +The example 8x8 PGA package above will have pin numbers 0 thru 63 assigned to +its physical pins. It will name the pins { A1, A2, A3 ... H6, H7, H8 } using +pinctrl_register_pins() and a suitable data set as shown earlier. + +In this 8x8 BGA package the pins { A8, A7, A6, A5 } can be used as an SPI port +(these are four pins: CLK, RXD, TXD, FRM). In that case, pin B5 can be used as +some general-purpose GPIO pin. However, in another setting, pins { A5, B5 } can +be used as an I2C port (these are just two pins: SCL, SDA). Needless to say, +we cannot use the SPI port and I2C port at the same time. However in the inside +of the package the silicon performing the SPI logic can alternatively be routed +out on pins { G4, G3, G2, G1 }. + +On the botton row at { A1, B1, C1, D1, E1, F1, G1, H1 } we have something +special - it's an external MMC bus that can be 2, 4 or 8 bits wide, and it will +consume 2, 4 or 8 pins respectively, so either { A1, B1 } are taken or +{ A1, B1, C1, D1 } or all of them. If we use all 8 bits, we cannot use the SPI +port on pins { G4, G3, G2, G1 } of course. + +This way the silicon blocks present inside the chip can be multiplexed "muxed" +out on different pin ranges. Often contemporary SoC (systems on chip) will +contain several I2C, SPI, SDIO/MMC, etc silicon blocks that can be routed to +different pins by pinmux settings. + +Since general-purpose I/O pins (GPIO) are typically always in shortage, it is +common to be able to use almost any pin as a GPIO pin if it is not currently +in use by some other I/O port. + + +Pinmux conventions +================== + +The purpose of the pinmux functionality in the pin controller subsystem is to +abstract and provide pinmux settings to the devices you choose to instantiate +in your machine configuration. It is inspired by the clk, GPIO and regulator +subsystems, so devices will request their mux setting, but it's also possible +to request a single pin for e.g. GPIO. + +Definitions: + +- FUNCTIONS can be switched in and out by a driver residing with the pin + control subsystem in the drivers/pinctrl/* directory of the kernel. The + pin control driver knows the possible functions. In the example above you can + identify three pinmux functions, one for spi, one for i2c and one for mmc. + +- FUNCTIONS are assumed to be enumerable from zero in a one-dimensional array. + In this case the array could be something like: { spi0, i2c0, mmc0 } + for the three available functions. + +- FUNCTIONS have PIN GROUPS as defined on the generic level - so a certain + function is *always* associated with a certain set of pin groups, could + be just a single one, but could also be many. In the example above the + function i2c is associated with the pins { A5, B5 }, enumerated as + { 24, 25 } in the controller pin space. + + The Function spi is associated with pin groups { A8, A7, A6, A5 } + and { G4, G3, G2, G1 }, which are enumerated as { 0, 8, 16, 24 } and + { 38, 46, 54, 62 } respectively. + + Group names must be unique per pin controller, no two groups on the same + controller may have the same name. + +- The combination of a FUNCTION and a PIN GROUP determine a certain function + for a certain set of pins. The knowledge of the functions and pin groups + and their machine-specific particulars are kept inside the pinmux driver, + from the outside only the enumerators are known, and the driver core can: + + - Request the name of a function with a certain selector (>= 0) + - A list of groups associated with a certain function + - Request that a certain group in that list to be activated for a certain + function + + As already described above, pin groups are in turn self-descriptive, so + the core will retrieve the actual pin range in a certain group from the + driver. + +- FUNCTIONS and GROUPS on a certain PIN CONTROLLER are MAPPED to a certain + device by the board file, device tree or similar machine setup configuration + mechanism, similar to how regulators are connected to devices, usually by + name. Defining a pin controller, function and group thus uniquely identify + the set of pins to be used by a certain device. (If only one possible group + of pins is available for the function, no group name need to be supplied - + the core will simply select the first and only group available.) + + In the example case we can define that this particular machine shall + use device spi0 with pinmux function fspi0 group gspi0 and i2c0 on function + fi2c0 group gi2c0, on the primary pin controller, we get mappings + like these: + + { + {"map-spi0", spi0, pinctrl0, fspi0, gspi0}, + {"map-i2c0", i2c0, pinctrl0, fi2c0, gi2c0} + } + + Every map must be assigned a symbolic name, pin controller and function. + The group is not compulsory - if it is omitted the first group presented by + the driver as applicable for the function will be selected, which is + useful for simple cases. + + The device name is present in map entries tied to specific devices. Maps + without device names are referred to as SYSTEM pinmuxes, such as can be taken + by the machine implementation on boot and not tied to any specific device. + + It is possible to map several groups to the same combination of device, + pin controller and function. This is for cases where a certain function on + a certain pin controller may use different sets of pins in different + configurations. + +- PINS for a certain FUNCTION using a certain PIN GROUP on a certain + PIN CONTROLLER are provided on a first-come first-serve basis, so if some + other device mux setting or GPIO pin request has already taken your physical + pin, you will be denied the use of it. To get (activate) a new setting, the + old one has to be put (deactivated) first. + +Sometimes the documentation and hardware registers will be oriented around +pads (or "fingers") rather than pins - these are the soldering surfaces on the +silicon inside the package, and may or may not match the actual number of +pins/balls underneath the capsule. Pick some enumeration that makes sense to +you. Define enumerators only for the pins you can control if that makes sense. + +Assumptions: + +We assume that the number possible function maps to pin groups is limited by +the hardware. I.e. we assume that there is no system where any function can be +mapped to any pin, like in a phone exchange. So the available pins groups for +a certain function will be limited to a few choices (say up to eight or so), +not hundreds or any amount of choices. This is the characteristic we have found +by inspecting available pinmux hardware, and a necessary assumption since we +expect pinmux drivers to present *all* possible function vs pin group mappings +to the subsystem. + + +Pinmux drivers +============== + +The pinmux core takes care of preventing conflicts on pins and calling +the pin controller driver to execute different settings. + +It is the responsibility of the pinmux driver to impose further restrictions +(say for example infer electronic limitations due to load etc) to determine +whether or not the requested function can actually be allowed, and in case it +is possible to perform the requested mux setting, poke the hardware so that +this happens. + +Pinmux drivers are required to supply a few callback functions, some are +optional. Usually the enable() and disable() functions are implemented, +writing values into some certain registers to activate a certain mux setting +for a certain pin. + +A simple driver for the above example will work by setting bits 0, 1, 2, 3 or 4 +into some register named MUX to select a certain function with a certain +group of pins would work something like this: + +#include <linux/pinctrl/pinctrl.h> +#include <linux/pinctrl/pinmux.h> + +struct foo_group { + const char *name; + const unsigned int *pins; + const unsigned num_pins; +}; + +static const unsigned spi0_0_pins[] = { 0, 8, 16, 24 }; +static const unsigned spi0_1_pins[] = { 38, 46, 54, 62 }; +static const unsigned i2c0_pins[] = { 24, 25 }; +static const unsigned mmc0_1_pins[] = { 56, 57 }; +static const unsigned mmc0_2_pins[] = { 58, 59 }; +static const unsigned mmc0_3_pins[] = { 60, 61, 62, 63 }; + +static const struct foo_group foo_groups[] = { + { + .name = "spi0_0_grp", + .pins = spi0_0_pins, + .num_pins = ARRAY_SIZE(spi0_0_pins), + }, + { + .name = "spi0_1_grp", + .pins = spi0_1_pins, + .num_pins = ARRAY_SIZE(spi0_1_pins), + }, + { + .name = "i2c0_grp", + .pins = i2c0_pins, + .num_pins = ARRAY_SIZE(i2c0_pins), + }, + { + .name = "mmc0_1_grp", + .pins = mmc0_1_pins, + .num_pins = ARRAY_SIZE(mmc0_1_pins), + }, + { + .name = "mmc0_2_grp", + .pins = mmc0_2_pins, + .num_pins = ARRAY_SIZE(mmc0_2_pins), + }, + { + .name = "mmc0_3_grp", + .pins = mmc0_3_pins, + .num_pins = ARRAY_SIZE(mmc0_3_pins), + }, +}; + + +static int foo_list_groups(struct pinctrl_dev *pctldev, unsigned selector) +{ + if (selector >= ARRAY_SIZE(foo_groups)) + return -EINVAL; + return 0; +} + +static const char *foo_get_group_name(struct pinctrl_dev *pctldev, + unsigned selector) +{ + return foo_groups[selector].name; +} + +static int foo_get_group_pins(struct pinctrl_dev *pctldev, unsigned selector, + unsigned ** const pins, + unsigned * const num_pins) +{ + *pins = (unsigned *) foo_groups[selector].pins; + *num_pins = foo_groups[selector].num_pins; + return 0; +} + +static struct pinctrl_ops foo_pctrl_ops = { + .list_groups = foo_list_groups, + .get_group_name = foo_get_group_name, + .get_group_pins = foo_get_group_pins, +}; + +struct foo_pmx_func { + const char *name; + const char * const *groups; + const unsigned num_groups; +}; + +static const char * const spi0_groups[] = { "spi0_1_grp" }; +static const char * const i2c0_groups[] = { "i2c0_grp" }; +static const char * const mmc0_groups[] = { "mmc0_1_grp", "mmc0_2_grp", + "mmc0_3_grp" }; + +static const struct foo_pmx_func foo_functions[] = { + { + .name = "spi0", + .groups = spi0_groups, + .num_groups = ARRAY_SIZE(spi0_groups), + }, + { + .name = "i2c0", + .groups = i2c0_groups, + .num_groups = ARRAY_SIZE(i2c0_groups), + }, + { + .name = "mmc0", + .groups = mmc0_groups, + .num_groups = ARRAY_SIZE(mmc0_groups), + }, +}; + +int foo_list_funcs(struct pinctrl_dev *pctldev, unsigned selector) +{ + if (selector >= ARRAY_SIZE(foo_functions)) + return -EINVAL; + return 0; +} + +const char *foo_get_fname(struct pinctrl_dev *pctldev, unsigned selector) +{ + return myfuncs[selector].name; +} + +static int foo_get_groups(struct pinctrl_dev *pctldev, unsigned selector, + const char * const **groups, + unsigned * const num_groups) +{ + *groups = foo_functions[selector].groups; + *num_groups = foo_functions[selector].num_groups; + return 0; +} + +int foo_enable(struct pinctrl_dev *pctldev, unsigned selector, + unsigned group) +{ + u8 regbit = (1 << group); + + writeb((readb(MUX)|regbit), MUX) + return 0; +} + +int foo_disable(struct pinctrl_dev *pctldev, unsigned selector, + unsigned group) +{ + u8 regbit = (1 << group); + + writeb((readb(MUX) & ~(regbit)), MUX) + return 0; +} + +struct pinmux_ops foo_pmxops = { + .list_functions = foo_list_funcs, + .get_function_name = foo_get_fname, + .get_function_groups = foo_get_groups, + .enable = foo_enable, + .disable = foo_disable, +}; + +/* Pinmux operations are handled by some pin controller */ +static struct pinctrl_desc foo_desc = { + ... + .pctlops = &foo_pctrl_ops, + .pmxops = &foo_pmxops, +}; + +In the example activating muxing 0 and 1 at the same time setting bits +0 and 1, uses one pin in common so they would collide. + +The beauty of the pinmux subsystem is that since it keeps track of all +pins and who is using them, it will already have denied an impossible +request like that, so the driver does not need to worry about such +things - when it gets a selector passed in, the pinmux subsystem makes +sure no other device or GPIO assignment is already using the selected +pins. Thus bits 0 and 1 in the control register will never be set at the +same time. + +All the above functions are mandatory to implement for a pinmux driver. + + +Pinmux interaction with the GPIO subsystem +========================================== + +The function list could become long, especially if you can convert every +individual pin into a GPIO pin independent of any other pins, and then try +the approach to define every pin as a function. + +In this case, the function array would become 64 entries for each GPIO +setting and then the device functions. + +For this reason there is an additional function a pinmux driver can implement +to enable only GPIO on an individual pin: .gpio_request_enable(). The same +.free() function as for other functions is assumed to be usable also for +GPIO pins. + +This function will pass in the affected GPIO range identified by the pin +controller core, so you know which GPIO pins are being affected by the request +operation. + +Alternatively it is fully allowed to use named functions for each GPIO +pin, the pinmux_request_gpio() will attempt to obtain the function "gpioN" +where "N" is the global GPIO pin number if no special GPIO-handler is +registered. + + +Pinmux board/machine configuration +================================== + +Boards and machines define how a certain complete running system is put +together, including how GPIOs and devices are muxed, how regulators are +constrained and how the clock tree looks. Of course pinmux settings are also +part of this. + +A pinmux config for a machine looks pretty much like a simple regulator +configuration, so for the example array above we want to enable i2c and +spi on the second function mapping: + +#include <linux/pinctrl/machine.h> + +static struct pinmux_map pmx_mapping[] = { + { + .ctrl_dev_name = "pinctrl.0", + .function = "spi0", + .dev_name = "foo-spi.0", + }, + { + .ctrl_dev_name = "pinctrl.0", + .function = "i2c0", + .dev_name = "foo-i2c.0", + }, + { + .ctrl_dev_name = "pinctrl.0", + .function = "mmc0", + .dev_name = "foo-mmc.0", + }, +}; + +The dev_name here matches to the unique device name that can be used to look +up the device struct (just like with clockdev or regulators). The function name +must match a function provided by the pinmux driver handling this pin range. + +As you can see we may have several pin controllers on the system and thus +we need to specify which one of them that contain the functions we wish +to map. The map can also use struct device * directly, so there is no +inherent need to use strings to specify .dev_name or .ctrl_dev_name, these +are for the situation where you do not have a handle to the struct device *, +for example if they are not yet instantiated or cumbersome to obtain. + +You register this pinmux mapping to the pinmux subsystem by simply: + + ret = pinmux_register_mappings(&pmx_mapping, ARRAY_SIZE(pmx_mapping)); + +Since the above construct is pretty common there is a helper macro to make +it even more compact which assumes you want to use pinctrl.0 and position +0 for mapping, for example: + +static struct pinmux_map pmx_mapping[] = { + PINMUX_MAP_PRIMARY("I2CMAP", "i2c0", "foo-i2c.0"), +}; + + +Complex mappings +================ + +As it is possible to map a function to different groups of pins an optional +.group can be specified like this: + +... +{ + .name = "spi0-pos-A", + .ctrl_dev_name = "pinctrl.0", + .function = "spi0", + .group = "spi0_0_grp", + .dev_name = "foo-spi.0", +}, +{ + .name = "spi0-pos-B", + .ctrl_dev_name = "pinctrl.0", + .function = "spi0", + .group = "spi0_1_grp", + .dev_name = "foo-spi.0", +}, +... + +This example mapping is used to switch between two positions for spi0 at +runtime, as described further below under the heading "Runtime pinmuxing". + +Further it is possible to match several groups of pins to the same function +for a single device, say for example in the mmc0 example above, where you can +additively expand the mmc0 bus from 2 to 4 to 8 pins. If we want to use all +three groups for a total of 2+2+4 = 8 pins (for an 8-bit MMC bus as is the +case), we define a mapping like this: + +... +{ + .name "2bit" + .ctrl_dev_name = "pinctrl.0", + .function = "mmc0", + .group = "mmc0_0_grp", + .dev_name = "foo-mmc.0", +}, +{ + .name "4bit" + .ctrl_dev_name = "pinctrl.0", + .function = "mmc0", + .group = "mmc0_0_grp", + .dev_name = "foo-mmc.0", +}, +{ + .name "4bit" + .ctrl_dev_name = "pinctrl.0", + .function = "mmc0", + .group = "mmc0_1_grp", + .dev_name = "foo-mmc.0", +}, +{ + .name "8bit" + .ctrl_dev_name = "pinctrl.0", + .function = "mmc0", + .group = "mmc0_0_grp", + .dev_name = "foo-mmc.0", +}, +{ + .name "8bit" + .ctrl_dev_name = "pinctrl.0", + .function = "mmc0", + .group = "mmc0_1_grp", + .dev_name = "foo-mmc.0", +}, +{ + .name "8bit" + .ctrl_dev_name = "pinctrl.0", + .function = "mmc0", + .group = "mmc0_2_grp", + .dev_name = "foo-mmc.0", +}, +... + +The result of grabbing this mapping from the device with something like +this (see next paragraph): + + pmx = pinmux_get(&device, "8bit"); + +Will be that you activate all the three bottom records in the mapping at +once. Since they share the same name, pin controller device, funcion and +device, and since we allow multiple groups to match to a single device, they +all get selected, and they all get enabled and disable simultaneously by the +pinmux core. + + +Pinmux requests from drivers +============================ + +Generally it is discouraged to let individual drivers get and enable pinmuxes. +So if possible, handle the pinmuxes in platform code or some other place where +you have access to all the affected struct device * pointers. In some cases +where a driver needs to switch between different mux mappings at runtime +this is not possible. + +A driver may request a certain mux to be activated, usually just the default +mux like this: + +#include <linux/pinctrl/pinmux.h> + +struct foo_state { + struct pinmux *pmx; + ... +}; + +foo_probe() +{ + /* Allocate a state holder named "state" etc */ + struct pinmux pmx; + + pmx = pinmux_get(&device, NULL); + if IS_ERR(pmx) + return PTR_ERR(pmx); + pinmux_enable(pmx); + + state->pmx = pmx; +} + +foo_remove() +{ + pinmux_disable(state->pmx); + pinmux_put(state->pmx); +} + +If you want to grab a specific mux mapping and not just the first one found for +this device you can specify a specific mapping name, for example in the above +example the second i2c0 setting: pinmux_get(&device, "spi0-pos-B"); + +This get/enable/disable/put sequence can just as well be handled by bus drivers +if you don't want each and every driver to handle it and you know the +arrangement on your bus. + +The semantics of the get/enable respective disable/put is as follows: + +- pinmux_get() is called in process context to reserve the pins affected with + a certain mapping and set up the pinmux core and the driver. It will allocate + a struct from the kernel memory to hold the pinmux state. + +- pinmux_enable()/pinmux_disable() is quick and can be called from fastpath + (irq context) when you quickly want to set up/tear down the hardware muxing + when running a device driver. Usually it will just poke some values into a + register. + +- pinmux_disable() is called in process context to tear down the pin requests + and release the state holder struct for the mux setting. + +Usually the pinmux core handled the get/put pair and call out to the device +drivers bookkeeping operations, like checking available functions and the +associated pins, whereas the enable/disable pass on to the pin controller +driver which takes care of activating and/or deactivating the mux setting by +quickly poking some registers. + +The pins are allocated for your device when you issue the pinmux_get() call, +after this you should be able to see this in the debugfs listing of all pins. + + +System pinmux hogging +===================== + +A system pinmux map entry, i.e. a pinmux setting that does not have a device +associated with it, can be hogged by the core when the pin controller is +registered. This means that the core will attempt to call pinmux_get() and +pinmux_enable() on it immediately after the pin control device has been +registered. + +This is enabled by simply setting the .hog_on_boot field in the map to true, +like this: + +{ + .name "POWERMAP" + .ctrl_dev_name = "pinctrl.0", + .function = "power_func", + .hog_on_boot = true, +}, + +Since it may be common to request the core to hog a few always-applicable +mux settings on the primary pin controller, there is a convenience macro for +this: + +PINMUX_MAP_PRIMARY_SYS_HOG("POWERMAP", "power_func") + +This gives the exact same result as the above construction. + + +Runtime pinmuxing +================= + +It is possible to mux a certain function in and out at runtime, say to move +an SPI port from one set of pins to another set of pins. Say for example for +spi0 in the example above, we expose two different groups of pins for the same +function, but with different named in the mapping as described under +"Advanced mapping" above. So we have two mappings named "spi0-pos-A" and +"spi0-pos-B". + +This snippet first muxes the function in the pins defined by group A, enables +it, disables and releases it, and muxes it in on the pins defined by group B: + +foo_switch() +{ + struct pinmux pmx; + + /* Enable on position A */ + pmx = pinmux_get(&device, "spi0-pos-A"); + if IS_ERR(pmx) + return PTR_ERR(pmx); + pinmux_enable(pmx); + + /* This releases the pins again */ + pinmux_disable(pmx); + pinmux_put(pmx); + + /* Enable on position B */ + pmx = pinmux_get(&device, "spi0-pos-B"); + if IS_ERR(pmx) + return PTR_ERR(pmx); + pinmux_enable(pmx); + ... +} + +The above has to be done from process context. diff --git a/Documentation/power/00-INDEX b/Documentation/power/00-INDEX index 45e9d4a9128..a4d682f5423 100644 --- a/Documentation/power/00-INDEX +++ b/Documentation/power/00-INDEX @@ -26,6 +26,8 @@ s2ram.txt - How to get suspend to ram working (and debug it when it isn't) states.txt - System power management states +suspend-and-cpuhotplug.txt + - Explains the interaction between Suspend-to-RAM (S3) and CPU hotplug swsusp-and-swap-files.txt - Using swap files with software suspend (to disk) swsusp-dmcrypt.txt diff --git a/Documentation/power/basic-pm-debugging.txt b/Documentation/power/basic-pm-debugging.txt index ddd78172ef7..40a4c65f380 100644 --- a/Documentation/power/basic-pm-debugging.txt +++ b/Documentation/power/basic-pm-debugging.txt @@ -173,7 +173,7 @@ kernel messages using the serial console. This may provide you with some information about the reasons of the suspend (resume) failure. Alternatively, it may be possible to use a FireWire port for debugging with firescope (ftp://ftp.firstfloor.org/pub/ak/firescope/). On x86 it is also possible to -use the PM_TRACE mechanism documented in Documentation/s2ram.txt . +use the PM_TRACE mechanism documented in Documentation/power/s2ram.txt . 2. Testing suspend to RAM (STR) @@ -201,3 +201,27 @@ case, you may be able to search for failing drivers by following the procedure analogous to the one described in section 1. If you find some failing drivers, you will have to unload them every time before an STR transition (ie. before you run s2ram), and please report the problems with them. + +There is a debugfs entry which shows the suspend to RAM statistics. Here is an +example of its output. + # mount -t debugfs none /sys/kernel/debug + # cat /sys/kernel/debug/suspend_stats + success: 20 + fail: 5 + failed_freeze: 0 + failed_prepare: 0 + failed_suspend: 5 + failed_suspend_noirq: 0 + failed_resume: 0 + failed_resume_noirq: 0 + failures: + last_failed_dev: alarm + adc + last_failed_errno: -16 + -16 + last_failed_step: suspend + suspend +Field success means the success number of suspend to RAM, and field fail means +the failure number. Others are the failure number of different steps of suspend +to RAM. suspend_stats just lists the last 2 failed devices, error number and +failed step of suspend. diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt index 3384d5996be..646a89e0c07 100644 --- a/Documentation/power/devices.txt +++ b/Documentation/power/devices.txt @@ -152,7 +152,9 @@ try to use its wakeup mechanism. device_set_wakeup_enable() affects this flag; for the most part drivers should not change its value. The initial value of should_wakeup is supposed to be false for the majority of devices; the major exceptions are power buttons, keyboards, and Ethernet adapters whose WoL -(wake-on-LAN) feature has been set up with ethtool. +(wake-on-LAN) feature has been set up with ethtool. It should also default +to true for devices that don't generate wakeup requests on their own but merely +forward wakeup requests from one bus to another (like PCI bridges). Whether or not a device is capable of issuing wakeup events is a hardware matter, and the kernel is responsible for keeping track of it. By contrast, @@ -279,10 +281,6 @@ When the system goes into the standby or memory sleep state, the phases are: time.) Unlike the other suspend-related phases, during the prepare phase the device tree is traversed top-down. - In addition to that, if device drivers need to allocate additional - memory to be able to hadle device suspend correctly, that should be - done in the prepare phase. - After the prepare callback method returns, no new children may be registered below the device. The method may also prepare the device or driver in some way for the upcoming system power transition (for diff --git a/Documentation/power/pm_qos_interface.txt b/Documentation/power/pm_qos_interface.txt index bfed898a03f..17e130a8034 100644 --- a/Documentation/power/pm_qos_interface.txt +++ b/Documentation/power/pm_qos_interface.txt @@ -4,14 +4,19 @@ This interface provides a kernel and user mode interface for registering performance expectations by drivers, subsystems and user space applications on one of the parameters. -Currently we have {cpu_dma_latency, network_latency, network_throughput} as the -initial set of pm_qos parameters. +Two different PM QoS frameworks are available: +1. PM QoS classes for cpu_dma_latency, network_latency, network_throughput. +2. the per-device PM QoS framework provides the API to manage the per-device latency +constraints. Each parameters have defined units: * latency: usec * timeout: usec * throughput: kbs (kilo bit / sec) + +1. PM QoS framework + The infrastructure exposes multiple misc device nodes one per implemented parameter. The set of parameters implement is defined by pm_qos_power_init() and pm_qos_params.h. This is done because having the available parameters @@ -23,14 +28,18 @@ an aggregated target value. The aggregated target value is updated with changes to the request list or elements of the list. Typically the aggregated target value is simply the max or min of the request values held in the parameter list elements. +Note: the aggregated target value is implemented as an atomic variable so that +reading the aggregated value does not require any locking mechanism. + From kernel mode the use of this interface is simple: -handle = pm_qos_add_request(param_class, target_value): -Will insert an element into the list for that identified PM_QOS class with the +void pm_qos_add_request(handle, param_class, target_value): +Will insert an element into the list for that identified PM QoS class with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. -Clients of pm_qos need to save the returned handle. +Clients of pm_qos need to save the returned handle for future use in other +pm_qos API functions. void pm_qos_update_request(handle, new_target_value): Will update the list element pointed to by the handle with the new target value @@ -42,6 +51,20 @@ Will remove the element. After removal it will update the aggregate target and call the notification tree if the target was changed as a result of removing the request. +int pm_qos_request(param_class): +Returns the aggregated value for a given PM QoS class. + +int pm_qos_request_active(handle): +Returns if the request is still active, i.e. it has not been removed from a +PM QoS class constraints list. + +int pm_qos_add_notifier(param_class, notifier): +Adds a notification callback function to the PM QoS class. The callback is +called when the aggregated value for the PM QoS class is changed. + +int pm_qos_remove_notifier(int param_class, notifier): +Removes the notification callback function for the PM QoS class. + From user mode: Only processes can register a pm_qos request. To provide for automatic @@ -63,4 +86,63 @@ To remove the user mode request for a target value simply close the device node. +2. PM QoS per-device latency framework + +For each device a list of performance requests is maintained along with +an aggregated target value. The aggregated target value is updated with +changes to the request list or elements of the list. Typically the +aggregated target value is simply the max or min of the request values held +in the parameter list elements. +Note: the aggregated target value is implemented as an atomic variable so that +reading the aggregated value does not require any locking mechanism. + + +From kernel mode the use of this interface is the following: + +int dev_pm_qos_add_request(device, handle, value): +Will insert an element into the list for that identified device with the +target value. Upon change to this list the new target is recomputed and any +registered notifiers are called only if the target value is now different. +Clients of dev_pm_qos need to save the handle for future use in other +dev_pm_qos API functions. + +int dev_pm_qos_update_request(handle, new_value): +Will update the list element pointed to by the handle with the new target value +and recompute the new aggregated target, calling the notification trees if the +target is changed. + +int dev_pm_qos_remove_request(handle): +Will remove the element. After removal it will update the aggregate target and +call the notification trees if the target was changed as a result of removing +the request. + +s32 dev_pm_qos_read_value(device): +Returns the aggregated value for a given device's constraints list. + + +Notification mechanisms: +The per-device PM QoS framework has 2 different and distinct notification trees: +a per-device notification tree and a global notification tree. + +int dev_pm_qos_add_notifier(device, notifier): +Adds a notification callback function for the device. +The callback is called when the aggregated value of the device constraints list +is changed. + +int dev_pm_qos_remove_notifier(device, notifier): +Removes the notification callback function for the device. + +int dev_pm_qos_add_global_notifier(notifier): +Adds a notification callback function in the global notification tree of the +framework. +The callback is called when the aggregated value for any device is changed. + +int dev_pm_qos_remove_global_notifier(notifier): +Removes the notification callback function from the global notification tree +of the framework. + + +From user mode: +No API for user space access to the per-device latency constraints is provided +yet - still under discussion. diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 4ce5450ab6e..0e856088db7 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -43,13 +43,18 @@ struct dev_pm_ops { ... }; -The ->runtime_suspend(), ->runtime_resume() and ->runtime_idle() callbacks are -executed by the PM core for either the device type, or the class (if the device -type's struct dev_pm_ops object does not exist), or the bus type (if the -device type's and class' struct dev_pm_ops objects do not exist) of the given -device (this allows device types to override callbacks provided by bus types or -classes if necessary). The bus type, device type and class callbacks are -referred to as subsystem-level callbacks in what follows. +The ->runtime_suspend(), ->runtime_resume() and ->runtime_idle() callbacks +are executed by the PM core for either the power domain, or the device type +(if the device power domain's struct dev_pm_ops does not exist), or the class +(if the device power domain's and type's struct dev_pm_ops object does not +exist), or the bus type (if the device power domain's, type's and class' +struct dev_pm_ops objects do not exist) of the given device, so the priority +order of callbacks from high to low is that power domain callbacks, device +type callbacks, class callbacks and bus type callbacks, and the high priority +one will take precedence over low priority one. The bus type, device type and +class callbacks are referred to as subsystem-level callbacks in what follows, +and generally speaking, the power domain callbacks are used for representing +power domains within a SoC. By default, the callbacks are always invoked in process context with interrupts enabled. However, subsystems can use the pm_runtime_irq_safe() helper function @@ -431,8 +436,7 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: void pm_runtime_irq_safe(struct device *dev); - set the power.irq_safe flag for the device, causing the runtime-PM - suspend and resume callbacks (but not the idle callback) to be invoked - with interrupts disabled + callbacks to be invoked with interrupts off void pm_runtime_mark_last_busy(struct device *dev); - set the power.last_busy field to the current time @@ -478,12 +482,14 @@ pm_runtime_autosuspend_expiration() If pm_runtime_irq_safe() has been called for a device then the following helper functions may also be used in interrupt context: +pm_runtime_idle() pm_runtime_suspend() pm_runtime_autosuspend() pm_runtime_resume() pm_runtime_get_sync() pm_runtime_put_sync() pm_runtime_put_sync_suspend() +pm_runtime_put_sync_autosuspend() 5. Runtime PM Initialization, Device Probing and Removal diff --git a/Documentation/power/suspend-and-cpuhotplug.txt b/Documentation/power/suspend-and-cpuhotplug.txt new file mode 100644 index 00000000000..f28f9a6f034 --- /dev/null +++ b/Documentation/power/suspend-and-cpuhotplug.txt @@ -0,0 +1,275 @@ +Interaction of Suspend code (S3) with the CPU hotplug infrastructure + + (C) 2011 Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> + + +I. How does the regular CPU hotplug code differ from how the Suspend-to-RAM + infrastructure uses it internally? And where do they share common code? + +Well, a picture is worth a thousand words... So ASCII art follows :-) + +[This depicts the current design in the kernel, and focusses only on the +interactions involving the freezer and CPU hotplug and also tries to explain +the locking involved. It outlines the notifications involved as well. +But please note that here, only the call paths are illustrated, with the aim +of describing where they take different paths and where they share code. +What happens when regular CPU hotplug and Suspend-to-RAM race with each other +is not depicted here.] + +On a high level, the suspend-resume cycle goes like this: + +|Freeze| -> |Disable nonboot| -> |Do suspend| -> |Enable nonboot| -> |Thaw | +|tasks | | cpus | | | | cpus | |tasks| + + +More details follow: + + Suspend call path + ----------------- + + Write 'mem' to + /sys/power/state + syfs file + | + v + Acquire pm_mutex lock + | + v + Send PM_SUSPEND_PREPARE + notifications + | + v + Freeze tasks + | + | + v + disable_nonboot_cpus() + /* start */ + | + v + Acquire cpu_add_remove_lock + | + v + Iterate over CURRENTLY + online CPUs + | + | + | ---------- + v | L + ======> _cpu_down() | + | [This takes cpuhotplug.lock | + Common | before taking down the CPU | + code | and releases it when done] | O + | While it is at it, notifications | + | are sent when notable events occur, | + ======> by running all registered callbacks. | + | | O + | | + | | + v | + Note down these cpus in | P + frozen_cpus mask ---------- + | + v + Disable regular cpu hotplug + by setting cpu_hotplug_disabled=1 + | + v + Release cpu_add_remove_lock + | + v + /* disable_nonboot_cpus() complete */ + | + v + Do suspend + + + +Resuming back is likewise, with the counterparts being (in the order of +execution during resume): +* enable_nonboot_cpus() which involves: + | Acquire cpu_add_remove_lock + | Reset cpu_hotplug_disabled to 0, thereby enabling regular cpu hotplug + | Call _cpu_up() [for all those cpus in the frozen_cpus mask, in a loop] + | Release cpu_add_remove_lock + v + +* thaw tasks +* send PM_POST_SUSPEND notifications +* Release pm_mutex lock. + + +It is to be noted here that the pm_mutex lock is acquired at the very +beginning, when we are just starting out to suspend, and then released only +after the entire cycle is complete (i.e., suspend + resume). + + + + Regular CPU hotplug call path + ----------------------------- + + Write 0 (or 1) to + /sys/devices/system/cpu/cpu*/online + sysfs file + | + | + v + cpu_down() + | + v + Acquire cpu_add_remove_lock + | + v + If cpu_hotplug_disabled is 1 + return gracefully + | + | + v + ======> _cpu_down() + | [This takes cpuhotplug.lock + Common | before taking down the CPU + code | and releases it when done] + | While it is at it, notifications + | are sent when notable events occur, + ======> by running all registered callbacks. + | + | + v + Release cpu_add_remove_lock + [That's it!, for + regular CPU hotplug] + + + +So, as can be seen from the two diagrams (the parts marked as "Common code"), +regular CPU hotplug and the suspend code path converge at the _cpu_down() and +_cpu_up() functions. They differ in the arguments passed to these functions, +in that during regular CPU hotplug, 0 is passed for the 'tasks_frozen' +argument. But during suspend, since the tasks are already frozen by the time +the non-boot CPUs are offlined or onlined, the _cpu_*() functions are called +with the 'tasks_frozen' argument set to 1. +[See below for some known issues regarding this.] + + +Important files and functions/entry points: +------------------------------------------ + +kernel/power/process.c : freeze_processes(), thaw_processes() +kernel/power/suspend.c : suspend_prepare(), suspend_enter(), suspend_finish() +kernel/cpu.c: cpu_[up|down](), _cpu_[up|down](), [disable|enable]_nonboot_cpus() + + + +II. What are the issues involved in CPU hotplug? + ------------------------------------------- + +There are some interesting situations involving CPU hotplug and microcode +update on the CPUs, as discussed below: + +[Please bear in mind that the kernel requests the microcode images from +userspace, using the request_firmware() function defined in +drivers/base/firmware_class.c] + + +a. When all the CPUs are identical: + + This is the most common situation and it is quite straightforward: we want + to apply the same microcode revision to each of the CPUs. + To give an example of x86, the collect_cpu_info() function defined in + arch/x86/kernel/microcode_core.c helps in discovering the type of the CPU + and thereby in applying the correct microcode revision to it. + But note that the kernel does not maintain a common microcode image for the + all CPUs, in order to handle case 'b' described below. + + +b. When some of the CPUs are different than the rest: + + In this case since we probably need to apply different microcode revisions + to different CPUs, the kernel maintains a copy of the correct microcode + image for each CPU (after appropriate CPU type/model discovery using + functions such as collect_cpu_info()). + + +c. When a CPU is physically hot-unplugged and a new (and possibly different + type of) CPU is hot-plugged into the system: + + In the current design of the kernel, whenever a CPU is taken offline during + a regular CPU hotplug operation, upon receiving the CPU_DEAD notification + (which is sent by the CPU hotplug code), the microcode update driver's + callback for that event reacts by freeing the kernel's copy of the + microcode image for that CPU. + + Hence, when a new CPU is brought online, since the kernel finds that it + doesn't have the microcode image, it does the CPU type/model discovery + afresh and then requests the userspace for the appropriate microcode image + for that CPU, which is subsequently applied. + + For example, in x86, the mc_cpu_callback() function (which is the microcode + update driver's callback registered for CPU hotplug events) calls + microcode_update_cpu() which would call microcode_init_cpu() in this case, + instead of microcode_resume_cpu() when it finds that the kernel doesn't + have a valid microcode image. This ensures that the CPU type/model + discovery is performed and the right microcode is applied to the CPU after + getting it from userspace. + + +d. Handling microcode update during suspend/hibernate: + + Strictly speaking, during a CPU hotplug operation which does not involve + physically removing or inserting CPUs, the CPUs are not actually powered + off during a CPU offline. They are just put to the lowest C-states possible. + Hence, in such a case, it is not really necessary to re-apply microcode + when the CPUs are brought back online, since they wouldn't have lost the + image during the CPU offline operation. + + This is the usual scenario encountered during a resume after a suspend. + However, in the case of hibernation, since all the CPUs are completely + powered off, during restore it becomes necessary to apply the microcode + images to all the CPUs. + + [Note that we don't expect someone to physically pull out nodes and insert + nodes with a different type of CPUs in-between a suspend-resume or a + hibernate/restore cycle.] + + In the current design of the kernel however, during a CPU offline operation + as part of the suspend/hibernate cycle (the CPU_DEAD_FROZEN notification), + the existing copy of microcode image in the kernel is not freed up. + And during the CPU online operations (during resume/restore), since the + kernel finds that it already has copies of the microcode images for all the + CPUs, it just applies them to the CPUs, avoiding any re-discovery of CPU + type/model and the need for validating whether the microcode revisions are + right for the CPUs or not (due to the above assumption that physical CPU + hotplug will not be done in-between suspend/resume or hibernate/restore + cycles). + + +III. Are there any known problems when regular CPU hotplug and suspend race + with each other? + +Yes, they are listed below: + +1. When invoking regular CPU hotplug, the 'tasks_frozen' argument passed to + the _cpu_down() and _cpu_up() functions is *always* 0. + This might not reflect the true current state of the system, since the + tasks could have been frozen by an out-of-band event such as a suspend + operation in progress. Hence, it will lead to wrong notifications being + sent during the cpu online/offline events (eg, CPU_ONLINE notification + instead of CPU_ONLINE_FROZEN) which in turn will lead to execution of + inappropriate code by the callbacks registered for such CPU hotplug events. + +2. If a regular CPU hotplug stress test happens to race with the freezer due + to a suspend operation in progress at the same time, then we could hit the + situation described below: + + * A regular cpu online operation continues its journey from userspace + into the kernel, since the freezing has not yet begun. + * Then freezer gets to work and freezes userspace. + * If cpu online has not yet completed the microcode update stuff by now, + it will now start waiting on the frozen userspace in the + TASK_UNINTERRUPTIBLE state, in order to get the microcode image. + * Now the freezer continues and tries to freeze the remaining tasks. But + due to this wait mentioned above, the freezer won't be able to freeze + the cpu online hotplug task and hence freezing of tasks fails. + + As a result of this task freezing failure, the suspend operation gets + aborted. diff --git a/Documentation/power/userland-swsusp.txt b/Documentation/power/userland-swsusp.txt index 1101bee4e82..0e870825c1b 100644 --- a/Documentation/power/userland-swsusp.txt +++ b/Documentation/power/userland-swsusp.txt @@ -77,7 +77,8 @@ SNAPSHOT_SET_SWAP_AREA - set the resume partition and the offset (in <PAGE_SIZE> resume_swap_area, as defined in kernel/power/suspend_ioctls.h, containing the resume device specification and the offset); for swap partitions the offset is always 0, but it is different from zero for - swap files (see Documentation/swsusp-and-swap-files.txt for details). + swap files (see Documentation/power/swsusp-and-swap-files.txt for + details). SNAPSHOT_PLATFORM_SUPPORT - enable/disable the hibernation platform support, depending on the argument value (enable, if the argument is nonzero) diff --git a/Documentation/rfkill.txt b/Documentation/rfkill.txt index 83668e5dd17..03c9d9299c6 100644 --- a/Documentation/rfkill.txt +++ b/Documentation/rfkill.txt @@ -117,5 +117,4 @@ The contents of these variables corresponds to the "name", "state" and "type" sysfs files explained above. -For further details consult Documentation/ABI/stable/dev-rfkill and -Documentation/ABI/stable/sysfs-class-rfkill. +For further details consult Documentation/ABI/stable/sysfs-class-rfkill. diff --git a/Documentation/scsi/aic7xxx_old.txt b/Documentation/scsi/aic7xxx_old.txt index 7bd210ab45a..ecfc474f36a 100644 --- a/Documentation/scsi/aic7xxx_old.txt +++ b/Documentation/scsi/aic7xxx_old.txt @@ -444,7 +444,7 @@ linux-1.1.x and fairly stable since linux-1.2.x, and are also in FreeBSD Kernel Compile options ------------------------------ The various kernel compile time options for this driver are now fairly - well documented in the file Documentation/Configure.help. In order to + well documented in the file drivers/scsi/Kconfig. In order to see this documentation, you need to use one of the advanced configuration programs (menuconfig and xconfig). If you are using the "make menuconfig" method of configuring your kernel, then you would simply highlight the diff --git a/Documentation/scsi/scsi_mid_low_api.txt b/Documentation/scsi/scsi_mid_low_api.txt index 5f17d29c59b..a340b18cd4e 100644 --- a/Documentation/scsi/scsi_mid_low_api.txt +++ b/Documentation/scsi/scsi_mid_low_api.txt @@ -55,11 +55,6 @@ or in the same directory as the C source code. For example to find a url about the USB mass storage driver see the /usr/src/linux/drivers/usb/storage directory. -The Linux kernel source Documentation/DocBook/scsidrivers.tmpl file -refers to this file. With the appropriate DocBook tool-set, this permits -users to generate html, ps and pdf renderings of information within this -file (e.g. the interface functions). - Driver structure ================ Traditionally an LLD for the SCSI subsystem has been at least two files in diff --git a/Documentation/security/keys-trusted-encrypted.txt b/Documentation/security/keys-trusted-encrypted.txt index 5f50ccabfc8..c9e4855ed3d 100644 --- a/Documentation/security/keys-trusted-encrypted.txt +++ b/Documentation/security/keys-trusted-encrypted.txt @@ -156,4 +156,5 @@ Load an encrypted key "evm" from saved blob: Other uses for trusted and encrypted keys, such as for disk and file encryption are anticipated. In particular the new format 'ecryptfs' has been defined in in order to use encrypted keys to mount an eCryptfs filesystem. More details -about the usage can be found in the file 'Documentation/keys-ecryptfs.txt'. +about the usage can be found in the file +'Documentation/security/keys-ecryptfs.txt'. diff --git a/Documentation/serial/serial-rs485.txt b/Documentation/serial/serial-rs485.txt index a4932387bbf..079cb3df62c 100644 --- a/Documentation/serial/serial-rs485.txt +++ b/Documentation/serial/serial-rs485.txt @@ -28,6 +28,10 @@ RS485 communications. This data structure is used to set and configure RS485 parameters in the platform data and in ioctls. + The device tree can also provide RS485 boot time parameters (see [2] + for bindings). The driver is in charge of filling this data structure from + the values given by the device tree. + Any driver for devices capable of working both as RS232 and RS485 should provide at least the following ioctls: @@ -104,6 +108,9 @@ rs485conf.flags |= SER_RS485_RTS_AFTER_SEND; rs485conf.delay_rts_after_send = ...; + /* Set this flag if you want to receive data even whilst sending data */ + rs485conf.flags |= SER_RS485_RX_DURING_TX; + if (ioctl (fd, TIOCSRS485, &rs485conf) < 0) { /* Error handling. See errno. */ } @@ -118,3 +125,4 @@ 5. REFERENCES [1] include/linux/serial.h + [2] Documentation/devicetree/bindings/serial/rs485.txt diff --git a/Documentation/sound/oss/PAS16 b/Documentation/sound/oss/PAS16 index 951b3dce51b..3dca4b75988 100644 --- a/Documentation/sound/oss/PAS16 +++ b/Documentation/sound/oss/PAS16 @@ -60,8 +60,7 @@ With PAS16 you can use two audio device files at the same time. /dev/dsp (and The new stuff for 2.3.99 and later ============================================================================ -The following configuration options from Documentation/Configure.help -are relevant to configuring the PAS16: +The following configuration options are relevant to configuring the PAS16: Sound card support CONFIG_SOUND diff --git a/Documentation/spi/pxa2xx b/Documentation/spi/pxa2xx index 00511e08db7..3352f97430e 100644 --- a/Documentation/spi/pxa2xx +++ b/Documentation/spi/pxa2xx @@ -2,7 +2,7 @@ PXA2xx SPI on SSP driver HOWTO =================================================== This a mini howto on the pxa2xx_spi driver. The driver turns a PXA2xx synchronous serial port into a SPI master controller -(see Documentation/spi/spi_summary). The driver has the following features +(see Documentation/spi/spi-summary). The driver has the following features - Support for any PXA2xx SSP - SSP PIO and SSP DMA data transfers. @@ -85,7 +85,7 @@ Declaring Slave Devices ----------------------- Typically each SPI slave (chip) is defined in the arch/.../mach-*/board-*.c using the "spi_board_info" structure found in "linux/spi/spi.h". See -"Documentation/spi/spi_summary" for additional information. +"Documentation/spi/spi-summary" for additional information. Each slave device attached to the PXA must provide slave specific configuration information via the structure "pxa2xx_spi_chip" found in diff --git a/Documentation/stable_kernel_rules.txt b/Documentation/stable_kernel_rules.txt index e213f45cf9d..21fd05c28e7 100644 --- a/Documentation/stable_kernel_rules.txt +++ b/Documentation/stable_kernel_rules.txt @@ -24,10 +24,10 @@ Rules on what kind of patches are accepted, and which ones are not, into the Procedure for submitting patches to the -stable tree: - Send the patch, after verifying that it follows the above rules, to - stable@kernel.org. You must note the upstream commit ID in the changelog - of your submission. + stable@vger.kernel.org. You must note the upstream commit ID in the + changelog of your submission. - To have the patch automatically included in the stable tree, add the tag - Cc: stable@kernel.org + Cc: stable@vger.kernel.org in the sign-off area. Once the patch is merged it will be applied to the stable tree without anything else needing to be done by the author or subsystem maintainer. @@ -35,10 +35,10 @@ Procedure for submitting patches to the -stable tree: cherry-picked than this can be specified in the following format in the sign-off area: - Cc: <stable@kernel.org> # .32.x: a1f84a3: sched: Check for idle - Cc: <stable@kernel.org> # .32.x: 1b9508f: sched: Rate-limit newidle - Cc: <stable@kernel.org> # .32.x: fd21073: sched: Fix affinity logic - Cc: <stable@kernel.org> # .32.x + Cc: <stable@vger.kernel.org> # .32.x: a1f84a3: sched: Check for idle + Cc: <stable@vger.kernel.org> # .32.x: 1b9508f: sched: Rate-limit newidle + Cc: <stable@vger.kernel.org> # .32.x: fd21073: sched: Fix affinity logic + Cc: <stable@vger.kernel.org> # .32.x Signed-off-by: Ingo Molnar <mingo@elte.hu> The tag sequence has the meaning of: diff --git a/Documentation/timers/highres.txt b/Documentation/timers/highres.txt index 21332233cef..e8789976e77 100644 --- a/Documentation/timers/highres.txt +++ b/Documentation/timers/highres.txt @@ -30,7 +30,7 @@ hrtimer base infrastructure --------------------------- The hrtimer base infrastructure was merged into the 2.6.16 kernel. Details of -the base implementation are covered in Documentation/hrtimers/hrtimer.txt. See +the base implementation are covered in Documentation/timers/hrtimers.txt. See also figure #2 (OLS slides p. 15) The main differences to the timer wheel, which holds the armed timer_list type diff --git a/Documentation/usb/dma.txt b/Documentation/usb/dma.txt index 84ef865237d..444651e70d9 100644 --- a/Documentation/usb/dma.txt +++ b/Documentation/usb/dma.txt @@ -7,7 +7,7 @@ API OVERVIEW The big picture is that USB drivers can continue to ignore most DMA issues, though they still must provide DMA-ready buffers (see -Documentation/PCI/PCI-DMA-mapping.txt). That's how they've worked through +Documentation/DMA-API-HOWTO.txt). That's how they've worked through the 2.4 (and earlier) kernels. OR: they can now be DMA-aware. @@ -57,7 +57,7 @@ and effects like cache-trashing can impose subtle penalties. force a consistent memory access ordering by using memory barriers. It's not using a streaming DMA mapping, so it's good for small transfers on systems where the I/O would otherwise thrash an IOMMU mapping. (See - Documentation/PCI/PCI-DMA-mapping.txt for definitions of "coherent" and + Documentation/DMA-API-HOWTO.txt for definitions of "coherent" and "streaming" DMA mappings.) Asking for 1/Nth of a page (as well as asking for N pages) is reasonably @@ -88,7 +88,7 @@ WORKING WITH EXISTING BUFFERS Existing buffers aren't usable for DMA without first being mapped into the DMA address space of the device. However, most buffers passed to your driver can safely be used with such DMA mapping. (See the first section -of Documentation/PCI/PCI-DMA-mapping.txt, titled "What memory is DMA-able?") +of Documentation/DMA-API-HOWTO.txt, titled "What memory is DMA-able?") - When you're using scatterlists, you can map everything at once. On some systems, this kicks in an IOMMU and turns the scatterlists into single diff --git a/Documentation/usb/dwc3.txt b/Documentation/usb/dwc3.txt new file mode 100644 index 00000000000..7b590edae14 --- /dev/null +++ b/Documentation/usb/dwc3.txt @@ -0,0 +1,45 @@ + + TODO +~~~~~~ +Please pick something while reading :) + +- Convert interrupt handler to per-ep-thread-irq + + As it turns out some DWC3-commands ~1ms to complete. Currently we spin + until the command completes which is bad. + + Implementation idea: + - dwc core implements a demultiplexing irq chip for interrupts per + endpoint. The interrupt numbers are allocated during probe and belong + to the device. If MSI provides per-endpoint interrupt this dummy + interrupt chip can be replaced with "real" interrupts. + - interrupts are requested / allocated on usb_ep_enable() and removed on + usb_ep_disable(). Worst case are 32 interrupts, the lower limit is two + for ep0/1. + - dwc3_send_gadget_ep_cmd() will sleep in wait_for_completion_timeout() + until the command completes. + - the interrupt handler is split into the following pieces: + - primary handler of the device + goes through every event and calls generic_handle_irq() for event + it. On return from generic_handle_irq() in acknowledges the event + counter so interrupt goes away (eventually). + + - threaded handler of the device + none + + - primary handler of the EP-interrupt + reads the event and tries to process it. Everything that requries + sleeping is handed over to the Thread. The event is saved in an + per-endpoint data-structure. + We probably have to pay attention not to process events once we + handed something to thread so we don't process event X prio Y + where X > Y. + + - threaded handler of the EP-interrupt + handles the remaining EP work which might sleep such as waiting + for command completion. + + Latency: + There should be no increase in latency since the interrupt-thread has a + high priority and will be run before an average task in user land + (except the user changed priorities). diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt index c9ffa9ced7e..12511c98cc4 100644 --- a/Documentation/usb/power-management.txt +++ b/Documentation/usb/power-management.txt @@ -439,10 +439,10 @@ cause autosuspends to fail with -EBUSY if the driver needs to use the device. External suspend calls should never be allowed to fail in this way, -only autosuspend calls. The driver can tell them apart by checking -the PM_EVENT_AUTO bit in the message.event argument to the suspend -method; this bit will be set for internal PM events (autosuspend) and -clear for external PM events. +only autosuspend calls. The driver can tell them apart by applying +the PMSG_IS_AUTO() macro to the message argument to the suspend +method; it will return True for internal PM events (autosuspend) and +False for external PM events. Mutual exclusion @@ -487,3 +487,29 @@ succeed, it may still remain active and thus cause the system to resume as soon as the system suspend is complete. Or the remote wakeup may fail and get lost. Which outcome occurs depends on timing and on the hardware and firmware design. + + + xHCI hardware link PM + --------------------- + +xHCI host controller provides hardware link power management to usb2.0 +(xHCI 1.0 feature) and usb3.0 devices which support link PM. By +enabling hardware LPM, the host can automatically put the device into +lower power state(L1 for usb2.0 devices, or U1/U2 for usb3.0 devices), +which state device can enter and resume very quickly. + +The user interface for controlling USB2 hardware LPM is located in the +power/ subdirectory of each USB device's sysfs directory, that is, in +/sys/bus/usb/devices/.../power/ where "..." is the device's ID. The +relevant attribute files is usb2_hardware_lpm. + + power/usb2_hardware_lpm + + When a USB2 device which support LPM is plugged to a + xHCI host root hub which support software LPM, the + host will run a software LPM test for it; if the device + enters L1 state and resume successfully and the host + supports USB2 hardware LPM, this file will show up and + driver will enable hardware LPM for the device. You + can write y/Y/1 or n/N/0 to the file to enable/disable + USB2 hardware LPM manually. This is for test purpose mainly. diff --git a/Documentation/virtual/00-INDEX b/Documentation/virtual/00-INDEX index fe0251c4cfb..8e601991d91 100644 --- a/Documentation/virtual/00-INDEX +++ b/Documentation/virtual/00-INDEX @@ -8,3 +8,6 @@ lguest/ - Extremely simple hypervisor for experimental/educational use. uml/ - User Mode Linux, builds/runs Linux kernel as a userspace program. +virtio.txt + - Text version of draft virtio spec. + See http://ozlabs.org/~rusty/virtio-spec diff --git a/Documentation/virtual/lguest/lguest.c b/Documentation/virtual/lguest/lguest.c index 043bd7df313..c095d79cae7 100644 --- a/Documentation/virtual/lguest/lguest.c +++ b/Documentation/virtual/lguest/lguest.c @@ -436,7 +436,7 @@ static unsigned long load_bzimage(int fd) /* * Go back to the start of the file and read the header. It should be - * a Linux boot header (see Documentation/x86/i386/boot.txt) + * a Linux boot header (see Documentation/x86/boot.txt) */ lseek(fd, 0, SEEK_SET); read(fd, &boot, sizeof(boot)); @@ -1996,6 +1996,9 @@ int main(int argc, char *argv[]) /* We use a simple helper to copy the arguments separated by spaces. */ concat((char *)(boot + 1), argv+optind+2); + /* Set kernel alignment to 16M (CONFIG_PHYSICAL_ALIGN) */ + boot->hdr.kernel_alignment = 0x1000000; + /* Boot protocol version: 2.07 supports the fields for lguest. */ boot->hdr.version = 0x207; diff --git a/Documentation/virtual/virtio-spec.txt b/Documentation/virtual/virtio-spec.txt new file mode 100644 index 00000000000..a350ae135b8 --- /dev/null +++ b/Documentation/virtual/virtio-spec.txt @@ -0,0 +1,2200 @@ +[Generated file: see http://ozlabs.org/~rusty/virtio-spec/] +Virtio PCI Card Specification +v0.9.1 DRAFT +- + +Rusty Russell <rusty@rustcorp.com.au>IBM Corporation (Editor) + +2011 August 1. + +Purpose and Description + +This document describes the specifications of the “virtio” family +of PCI[LaTeX Command: nomenclature] devices. These are devices +are found in virtual environments[LaTeX Command: nomenclature], +yet by design they are not all that different from physical PCI +devices, and this document treats them as such. This allows the +guest to use standard PCI drivers and discovery mechanisms. + +The purpose of virtio and this specification is that virtual +environments and guests should have a straightforward, efficient, +standard and extensible mechanism for virtual devices, rather +than boutique per-environment or per-OS mechanisms. + + Straightforward: Virtio PCI devices use normal PCI mechanisms + of interrupts and DMA which should be familiar to any device + driver author. There is no exotic page-flipping or COW + mechanism: it's just a PCI device.[footnote: +This lack of page-sharing implies that the implementation of the +device (e.g. the hypervisor or host) needs full access to the +guest memory. Communication with untrusted parties (i.e. +inter-guest communication) requires copying. +] + + Efficient: Virtio PCI devices consist of rings of descriptors + for input and output, which are neatly separated to avoid cache + effects from both guest and device writing to the same cache + lines. + + Standard: Virtio PCI makes no assumptions about the environment + in which it operates, beyond supporting PCI. In fact the virtio + devices specified in the appendices do not require PCI at all: + they have been implemented on non-PCI buses.[footnote: +The Linux implementation further separates the PCI virtio code +from the specific virtio drivers: these drivers are shared with +the non-PCI implementations (currently lguest and S/390). +] + + Extensible: Virtio PCI devices contain feature bits which are + acknowledged by the guest operating system during device setup. + This allows forwards and backwards compatibility: the device + offers all the features it knows about, and the driver + acknowledges those it understands and wishes to use. + + Virtqueues + +The mechanism for bulk data transport on virtio PCI devices is +pretentiously called a virtqueue. Each device can have zero or +more virtqueues: for example, the network device has one for +transmit and one for receive. + +Each virtqueue occupies two or more physically-contiguous pages +(defined, for the purposes of this specification, as 4096 bytes), +and consists of three parts: + + ++-------------------+-----------------------------------+-----------+ +| Descriptor Table | Available Ring (padding) | Used Ring | ++-------------------+-----------------------------------+-----------+ + + +When the driver wants to send buffers to the device, it puts them +in one or more slots in the descriptor table, and writes the +descriptor indices into the available ring. It then notifies the +device. When the device has finished with the buffers, it writes +the descriptors into the used ring, and sends an interrupt. + +Specification + + PCI Discovery + +Any PCI device with Vendor ID 0x1AF4, and Device ID 0x1000 +through 0x103F inclusive is a virtio device[footnote: +The actual value within this range is ignored +]. The device must also have a Revision ID of 0 to match this +specification. + +The Subsystem Device ID indicates which virtio device is +supported by the device. The Subsystem Vendor ID should reflect +the PCI Vendor ID of the environment (it's currently only used +for informational purposes by the guest). + + ++----------------------+--------------------+---------------+ +| Subsystem Device ID | Virtio Device | Specification | ++----------------------+--------------------+---------------+ ++----------------------+--------------------+---------------+ +| 1 | network card | Appendix C | ++----------------------+--------------------+---------------+ +| 2 | block device | Appendix D | ++----------------------+--------------------+---------------+ +| 3 | console | Appendix E | ++----------------------+--------------------+---------------+ +| 4 | entropy source | Appendix F | ++----------------------+--------------------+---------------+ +| 5 | memory ballooning | Appendix G | ++----------------------+--------------------+---------------+ +| 6 | ioMemory | - | ++----------------------+--------------------+---------------+ +| 9 | 9P transport | - | ++----------------------+--------------------+---------------+ + + + Device Configuration + +To configure the device, we use the first I/O region of the PCI +device. This contains a virtio header followed by a +device-specific region. + +There may be different widths of accesses to the I/O region; the “ +natural” access method for each field in the virtio header must +be used (i.e. 32-bit accesses for 32-bit fields, etc), but the +device-specific region can be accessed using any width accesses, +and should obtain the same results. + +Note that this is possible because while the virtio header is PCI +(i.e. little) endian, the device-specific region is encoded in +the native endian of the guest (where such distinction is +applicable). + + Device Initialization Sequence + +We start with an overview of device initialization, then expand +on the details of the device and how each step is preformed. + + Reset the device. This is not required on initial start up. + + The ACKNOWLEDGE status bit is set: we have noticed the device. + + The DRIVER status bit is set: we know how to drive the device. + + Device-specific setup, including reading the Device Feature + Bits, discovery of virtqueues for the device, optional MSI-X + setup, and reading and possibly writing the virtio + configuration space. + + The subset of Device Feature Bits understood by the driver is + written to the device. + + The DRIVER_OK status bit is set. + + The device can now be used (ie. buffers added to the + virtqueues)[footnote: +Historically, drivers have used the device before steps 5 and 6. +This is only allowed if the driver does not use any features +which would alter this early use of the device. +] + +If any of these steps go irrecoverably wrong, the guest should +set the FAILED status bit to indicate that it has given up on the +device (it can reset the device later to restart if desired). + +We now cover the fields required for general setup in detail. + + Virtio Header + +The virtio header looks as follows: + + ++------------++---------------------+---------------------+----------+--------+---------+---------+---------+--------+ +| Bits || 32 | 32 | 32 | 16 | 16 | 16 | 8 | 8 | ++------------++---------------------+---------------------+----------+--------+---------+---------+---------+--------+ +| Read/Write || R | R+W | R+W | R | R+W | R+W | R+W | R | ++------------++---------------------+---------------------+----------+--------+---------+---------+---------+--------+ +| Purpose || Device | Guest | Queue | Queue | Queue | Queue | Device | ISR | +| || Features bits 0:31 | Features bits 0:31 | Address | Size | Select | Notify | Status | Status | ++------------++---------------------+---------------------+----------+--------+---------+---------+---------+--------+ + + +If MSI-X is enabled for the device, two additional fields +immediately follow this header: + + ++------------++----------------+--------+ +| Bits || 16 | 16 | + +----------------+--------+ ++------------++----------------+--------+ +| Read/Write || R+W | R+W | ++------------++----------------+--------+ +| Purpose || Configuration | Queue | +| (MSI-X) || Vector | Vector | ++------------++----------------+--------+ + + +Finally, if feature bits (VIRTIO_F_FEATURES_HI) this is +immediately followed by two additional fields: + + ++------------++----------------------+---------------------- +| Bits || 32 | 32 ++------------++----------------------+---------------------- +| Read/Write || R | R+W ++------------++----------------------+---------------------- +| Purpose || Device | Guest +| || Features bits 32:63 | Features bits 32:63 ++------------++----------------------+---------------------- + + +Immediately following these general headers, there may be +device-specific headers: + + ++------------++--------------------+ +| Bits || Device Specific | + +--------------------+ ++------------++--------------------+ +| Read/Write || Device Specific | ++------------++--------------------+ +| Purpose || Device Specific... | +| || | ++------------++--------------------+ + + + Device Status + +The Device Status field is updated by the guest to indicate its +progress. This provides a simple low-level diagnostic: it's most +useful to imagine them hooked up to traffic lights on the console +indicating the status of each device. + +The device can be reset by writing a 0 to this field, otherwise +at least one bit should be set: + + ACKNOWLEDGE (1) Indicates that the guest OS has found the + device and recognized it as a valid virtio device. + + DRIVER (2) Indicates that the guest OS knows how to drive the + device. Under Linux, drivers can be loadable modules so there + may be a significant (or infinite) delay before setting this + bit. + + DRIVER_OK (3) Indicates that the driver is set up and ready to + drive the device. + + FAILED (8) Indicates that something went wrong in the guest, + and it has given up on the device. This could be an internal + error, or the driver didn't like the device for some reason, or + even a fatal error during device operation. The device must be + reset before attempting to re-initialize. + + Feature Bits + +The least significant 31 bits of the first configuration field +indicates the features that the device supports (the high bit is +reserved, and will be used to indicate the presence of future +feature bits elsewhere). If more than 31 feature bits are +supported, the device indicates so by setting feature bit 31 (see +[cha:Reserved-Feature-Bits]). The bits are allocated as follows: + + 0 to 23 Feature bits for the specific device type + + 24 to 40 Feature bits reserved for extensions to the queue and + feature negotiation mechanisms + + 41 to 63 Feature bits reserved for future extensions + +For example, feature bit 0 for a network device (i.e. Subsystem +Device ID 1) indicates that the device supports checksumming of +packets. + +The feature bits are negotiated: the device lists all the +features it understands in the Device Features field, and the +guest writes the subset that it understands into the Guest +Features field. The only way to renegotiate is to reset the +device. + +In particular, new fields in the device configuration header are +indicated by offering a feature bit, so the guest can check +before accessing that part of the configuration space. + +This allows for forwards and backwards compatibility: if the +device is enhanced with a new feature bit, older guests will not +write that feature bit back to the Guest Features field and it +can go into backwards compatibility mode. Similarly, if a guest +is enhanced with a feature that the device doesn't support, it +will not see that feature bit in the Device Features field and +can go into backwards compatibility mode (or, for poor +implementations, set the FAILED Device Status bit). + +Access to feature bits 32 to 63 is enabled by Guest by setting +feature bit 31. If this bit is unset, Device must assume that all +feature bits > 31 are unset. + + Configuration/Queue Vectors + +When MSI-X capability is present and enabled in the device +(through standard PCI configuration space) 4 bytes at byte offset +20 are used to map configuration change and queue interrupts to +MSI-X vectors. In this case, the ISR Status field is unused, and +device specific configuration starts at byte offset 24 in virtio +header structure. When MSI-X capability is not enabled, device +specific configuration starts at byte offset 20 in virtio header. + +Writing a valid MSI-X Table entry number, 0 to 0x7FF, to one of +Configuration/Queue Vector registers, maps interrupts triggered +by the configuration change/selected queue events respectively to +the corresponding MSI-X vector. To disable interrupts for a +specific event type, unmap it by writing a special NO_VECTOR +value: + +/* Vector value used to disable MSI for queue */ + +#define VIRTIO_MSI_NO_VECTOR 0xffff + +Reading these registers returns vector mapped to a given event, +or NO_VECTOR if unmapped. All queue and configuration change +events are unmapped by default. + +Note that mapping an event to vector might require allocating +internal device resources, and might fail. Devices report such +failures by returning the NO_VECTOR value when the relevant +Vector field is read. After mapping an event to vector, the +driver must verify success by reading the Vector field value: on +success, the previously written value is returned, and on +failure, NO_VECTOR is returned. If a mapping failure is detected, +the driver can retry mapping with fewervectors, or disable MSI-X. + + Virtqueue Configuration + +As a device can have zero or more virtqueues for bulk data +transport (for example, the network driver has two), the driver +needs to configure them as part of the device-specific +configuration. + +This is done as follows, for each virtqueue a device has: + + Write the virtqueue index (first queue is 0) to the Queue + Select field. + + Read the virtqueue size from the Queue Size field, which is + always a power of 2. This controls how big the virtqueue is + (see below). If this field is 0, the virtqueue does not exist. + + Allocate and zero virtqueue in contiguous physical memory, on a + 4096 byte alignment. Write the physical address, divided by + 4096 to the Queue Address field.[footnote: +The 4096 is based on the x86 page size, but it's also large +enough to ensure that the separate parts of the virtqueue are on +separate cache lines. +] + + Optionally, if MSI-X capability is present and enabled on the + device, select a vector to use to request interrupts triggered + by virtqueue events. Write the MSI-X Table entry number + corresponding to this vector in Queue Vector field. Read the + Queue Vector field: on success, previously written value is + returned; on failure, NO_VECTOR value is returned. + +The Queue Size field controls the total number of bytes required +for the virtqueue according to the following formula: + +#define ALIGN(x) (((x) + 4095) & ~4095) + +static inline unsigned vring_size(unsigned int qsz) + +{ + + return ALIGN(sizeof(struct vring_desc)*qsz + sizeof(u16)*(2 ++ qsz)) + + + ALIGN(sizeof(struct vring_used_elem)*qsz); + +} + +This currently wastes some space with padding, but also allows +future extensions. The virtqueue layout structure looks like this +(qsz is the Queue Size field, which is a variable, so this code +won't compile): + +struct vring { + + /* The actual descriptors (16 bytes each) */ + + struct vring_desc desc[qsz]; + + + + /* A ring of available descriptor heads with free-running +index. */ + + struct vring_avail avail; + + + + // Padding to the next 4096 boundary. + + char pad[]; + + + + // A ring of used descriptor heads with free-running index. + + struct vring_used used; + +}; + + A Note on Virtqueue Endianness + +Note that the endian of these fields and everything else in the +virtqueue is the native endian of the guest, not little-endian as +PCI normally is. This makes for simpler guest code, and it is +assumed that the host already has to be deeply aware of the guest +endian so such an “endian-aware” device is not a significant +issue. + + Descriptor Table + +The descriptor table refers to the buffers the guest is using for +the device. The addresses are physical addresses, and the buffers +can be chained via the next field. Each descriptor describes a +buffer which is read-only or write-only, but a chain of +descriptors can contain both read-only and write-only buffers. + +No descriptor chain may be more than 2^32 bytes long in total.struct vring_desc { + + /* Address (guest-physical). */ + + u64 addr; + + /* Length. */ + + u32 len; + +/* This marks a buffer as continuing via the next field. */ + +#define VRING_DESC_F_NEXT 1 + +/* This marks a buffer as write-only (otherwise read-only). */ + +#define VRING_DESC_F_WRITE 2 + +/* This means the buffer contains a list of buffer descriptors. +*/ + +#define VRING_DESC_F_INDIRECT 4 + + /* The flags as indicated above. */ + + u16 flags; + + /* Next field if flags & NEXT */ + + u16 next; + +}; + +The number of descriptors in the table is specified by the Queue +Size field for this virtqueue. + + <sub:Indirect-Descriptors>Indirect Descriptors + +Some devices benefit by concurrently dispatching a large number +of large requests. The VIRTIO_RING_F_INDIRECT_DESC feature can be +used to allow this (see [cha:Reserved-Feature-Bits]). To increase +ring capacity it is possible to store a table of indirect +descriptors anywhere in memory, and insert a descriptor in main +virtqueue (with flags&INDIRECT on) that refers to memory buffer +containing this indirect descriptor table; fields addr and len +refer to the indirect table address and length in bytes, +respectively. The indirect table layout structure looks like this +(len is the length of the descriptor that refers to this table, +which is a variable, so this code won't compile): + +struct indirect_descriptor_table { + + /* The actual descriptors (16 bytes each) */ + + struct vring_desc desc[len / 16]; + +}; + +The first indirect descriptor is located at start of the indirect +descriptor table (index 0), additional indirect descriptors are +chained by next field. An indirect descriptor without next field +(with flags&NEXT off) signals the end of the indirect descriptor +table, and transfers control back to the main virtqueue. An +indirect descriptor can not refer to another indirect descriptor +table (flags&INDIRECT must be off). A single indirect descriptor +table can include both read-only and write-only descriptors; +write-only flag (flags&WRITE) in the descriptor that refers to it +is ignored. + + Available Ring + +The available ring refers to what descriptors we are offering the +device: it refers to the head of a descriptor chain. The “flags” +field is currently 0 or 1: 1 indicating that we do not need an +interrupt when the device consumes a descriptor from the +available ring. Alternatively, the guest can ask the device to +delay interrupts until an entry with an index specified by the “ +used_event” field is written in the used ring (equivalently, +until the idx field in the used ring will reach the value +used_event + 1). The method employed by the device is controlled +by the VIRTIO_RING_F_EVENT_IDX feature bit (see [cha:Reserved-Feature-Bits] +). This interrupt suppression is merely an optimization; it may +not suppress interrupts entirely. + +The “idx” field indicates where we would put the next descriptor +entry (modulo the ring size). This starts at 0, and increases. + +struct vring_avail { + +#define VRING_AVAIL_F_NO_INTERRUPT 1 + + u16 flags; + + u16 idx; + + u16 ring[qsz]; /* qsz is the Queue Size field read from device +*/ + + u16 used_event; + +}; + + Used Ring + +The used ring is where the device returns buffers once it is done +with them. The flags field can be used by the device to hint that +no notification is necessary when the guest adds to the available +ring. Alternatively, the “avail_event” field can be used by the +device to hint that no notification is necessary until an entry +with an index specified by the “avail_event” is written in the +available ring (equivalently, until the idx field in the +available ring will reach the value avail_event + 1). The method +employed by the device is controlled by the guest through the +VIRTIO_RING_F_EVENT_IDX feature bit (see [cha:Reserved-Feature-Bits] +). [footnote: +These fields are kept here because this is the only part of the +virtqueue written by the device +]. + +Each entry in the ring is a pair: the head entry of the +descriptor chain describing the buffer (this matches an entry +placed in the available ring by the guest earlier), and the total +of bytes written into the buffer. The latter is extremely useful +for guests using untrusted buffers: if you do not know exactly +how much has been written by the device, you usually have to zero +the buffer to ensure no data leakage occurs. + +/* u32 is used here for ids for padding reasons. */ + +struct vring_used_elem { + + /* Index of start of used descriptor chain. */ + + u32 id; + + /* Total length of the descriptor chain which was used +(written to) */ + + u32 len; + +}; + + + +struct vring_used { + +#define VRING_USED_F_NO_NOTIFY 1 + + u16 flags; + + u16 idx; + + struct vring_used_elem ring[qsz]; + + u16 avail_event; + +}; + + Helpers for Managing Virtqueues + +The Linux Kernel Source code contains the definitions above and +helper routines in a more usable form, in +include/linux/virtio_ring.h. This was explicitly licensed by IBM +and Red Hat under the (3-clause) BSD license so that it can be +freely used by all other projects, and is reproduced (with slight +variation to remove Linux assumptions) in Appendix A. + + Device Operation + +There are two parts to device operation: supplying new buffers to +the device, and processing used buffers from the device. As an +example, the virtio network device has two virtqueues: the +transmit virtqueue and the receive virtqueue. The driver adds +outgoing (read-only) packets to the transmit virtqueue, and then +frees them after they are used. Similarly, incoming (write-only) +buffers are added to the receive virtqueue, and processed after +they are used. + + Supplying Buffers to The Device + +Actual transfer of buffers from the guest OS to the device +operates as follows: + + Place the buffer(s) into free descriptor(s). + + If there are no free descriptors, the guest may choose to + notify the device even if notifications are suppressed (to + reduce latency).[footnote: +The Linux drivers do this only for read-only buffers: for +write-only buffers, it is assumed that the driver is merely +trying to keep the receive buffer ring full, and no notification +of this expected condition is necessary. +] + + Place the id of the buffer in the next ring entry of the + available ring. + + The steps (1) and (2) may be performed repeatedly if batching + is possible. + + A memory barrier should be executed to ensure the device sees + the updated descriptor table and available ring before the next + step. + + The available “idx” field should be increased by the number of + entries added to the available ring. + + A memory barrier should be executed to ensure that we update + the idx field before checking for notification suppression. + + If notifications are not suppressed, the device should be + notified of the new buffers. + +Note that the above code does not take precautions against the +available ring buffer wrapping around: this is not possible since +the ring buffer is the same size as the descriptor table, so step +(1) will prevent such a condition. + +In addition, the maximum queue size is 32768 (it must be a power +of 2 which fits in 16 bits), so the 16-bit “idx” value can always +distinguish between a full and empty buffer. + +Here is a description of each stage in more detail. + + Placing Buffers Into The Descriptor Table + +A buffer consists of zero or more read-only physically-contiguous +elements followed by zero or more physically-contiguous +write-only elements (it must have at least one element). This +algorithm maps it into the descriptor table: + + for each buffer element, b: + + Get the next free descriptor table entry, d + + Set d.addr to the physical address of the start of b + + Set d.len to the length of b. + + If b is write-only, set d.flags to VRING_DESC_F_WRITE, + otherwise 0. + + If there is a buffer element after this: + + Set d.next to the index of the next free descriptor element. + + Set the VRING_DESC_F_NEXT bit in d.flags. + +In practice, the d.next fields are usually used to chain free +descriptors, and a separate count kept to check there are enough +free descriptors before beginning the mappings. + + Updating The Available Ring + +The head of the buffer we mapped is the first d in the algorithm +above. A naive implementation would do the following: + +avail->ring[avail->idx % qsz] = head; + +However, in general we can add many descriptors before we update +the “idx” field (at which point they become visible to the +device), so we keep a counter of how many we've added: + +avail->ring[(avail->idx + added++) % qsz] = head; + + Updating The Index Field + +Once the idx field of the virtqueue is updated, the device will +be able to access the descriptor entries we've created and the +memory they refer to. This is why a memory barrier is generally +used before the idx update, to ensure it sees the most up-to-date +copy. + +The idx field always increments, and we let it wrap naturally at +65536: + +avail->idx += added; + + <sub:Notifying-The-Device>Notifying The Device + +Device notification occurs by writing the 16-bit virtqueue index +of this virtqueue to the Queue Notify field of the virtio header +in the first I/O region of the PCI device. This can be expensive, +however, so the device can suppress such notifications if it +doesn't need them. We have to be careful to expose the new idx +value before checking the suppression flag: it's OK to notify +gratuitously, but not to omit a required notification. So again, +we use a memory barrier here before reading the flags or the +avail_event field. + +If the VIRTIO_F_RING_EVENT_IDX feature is not negotiated, and if +the VRING_USED_F_NOTIFY flag is not set, we go ahead and write to +the PCI configuration space. + +If the VIRTIO_F_RING_EVENT_IDX feature is negotiated, we read the +avail_event field in the available ring structure. If the +available index crossed_the avail_event field value since the +last notification, we go ahead and write to the PCI configuration +space. The avail_event field wraps naturally at 65536 as well: + +(u16)(new_idx - avail_event - 1) < (u16)(new_idx - old_idx) + + <sub:Receiving-Used-Buffers>Receiving Used Buffers From The + Device + +Once the device has used a buffer (read from or written to it, or +parts of both, depending on the nature of the virtqueue and the +device), it sends an interrupt, following an algorithm very +similar to the algorithm used for the driver to send the device a +buffer: + + Write the head descriptor number to the next field in the used + ring. + + Update the used ring idx. + + Determine whether an interrupt is necessary: + + If the VIRTIO_F_RING_EVENT_IDX feature is not negotiated: check + if f the VRING_AVAIL_F_NO_INTERRUPT flag is not set in avail- + >flags + + If the VIRTIO_F_RING_EVENT_IDX feature is negotiated: check + whether the used index crossed the used_event field value + since the last update. The used_event field wraps naturally + at 65536 as well:(u16)(new_idx - used_event - 1) < (u16)(new_idx - old_idx) + + If an interrupt is necessary: + + If MSI-X capability is disabled: + + Set the lower bit of the ISR Status field for the device. + + Send the appropriate PCI interrupt for the device. + + If MSI-X capability is enabled: + + Request the appropriate MSI-X interrupt message for the + device, Queue Vector field sets the MSI-X Table entry + number. + + If Queue Vector field value is NO_VECTOR, no interrupt + message is requested for this event. + +The guest interrupt handler should: + + If MSI-X capability is disabled: read the ISR Status field, + which will reset it to zero. If the lower bit is zero, the + interrupt was not for this device. Otherwise, the guest driver + should look through the used rings of each virtqueue for the + device, to see if any progress has been made by the device + which requires servicing. + + If MSI-X capability is enabled: look through the used rings of + each virtqueue mapped to the specific MSI-X vector for the + device, to see if any progress has been made by the device + which requires servicing. + +For each ring, guest should then disable interrupts by writing +VRING_AVAIL_F_NO_INTERRUPT flag in avail structure, if required. +It can then process used ring entries finally enabling interrupts +by clearing the VRING_AVAIL_F_NO_INTERRUPT flag or updating the +EVENT_IDX field in the available structure, Guest should then +execute a memory barrier, and then recheck the ring empty +condition. This is necessary to handle the case where, after the +last check and before enabling interrupts, an interrupt has been +suppressed by the device: + +vring_disable_interrupts(vq); + +for (;;) { + + if (vq->last_seen_used != vring->used.idx) { + + vring_enable_interrupts(vq); + + mb(); + + if (vq->last_seen_used != vring->used.idx) + + break; + + } + + struct vring_used_elem *e = +vring.used->ring[vq->last_seen_used%vsz]; + + process_buffer(e); + + vq->last_seen_used++; + +} + + Dealing With Configuration Changes + +Some virtio PCI devices can change the device configuration +state, as reflected in the virtio header in the PCI configuration +space. In this case: + + If MSI-X capability is disabled: an interrupt is delivered and + the second highest bit is set in the ISR Status field to + indicate that the driver should re-examine the configuration + space.Note that a single interrupt can indicate both that one + or more virtqueue has been used and that the configuration + space has changed: even if the config bit is set, virtqueues + must be scanned. + + If MSI-X capability is enabled: an interrupt message is + requested. The Configuration Vector field sets the MSI-X Table + entry number to use. If Configuration Vector field value is + NO_VECTOR, no interrupt message is requested for this event. + +Creating New Device Types + +Various considerations are necessary when creating a new device +type: + + How Many Virtqueues? + +It is possible that a very simple device will operate entirely +through its configuration space, but most will need at least one +virtqueue in which it will place requests. A device with both +input and output (eg. console and network devices described here) +need two queues: one which the driver fills with buffers to +receive input, and one which the driver places buffers to +transmit output. + + What Configuration Space Layout? + +Configuration space is generally used for rarely-changing or +initialization-time parameters. But it is a limited resource, so +it might be better to use a virtqueue to update configuration +information (the network device does this for filtering, +otherwise the table in the config space could potentially be very +large). + +Note that this space is generally the guest's native endian, +rather than PCI's little-endian. + + What Device Number? + +Currently device numbers are assigned quite freely: a simple +request mail to the author of this document or the Linux +virtualization mailing list[footnote: + +https://lists.linux-foundation.org/mailman/listinfo/virtualization +] will be sufficient to secure a unique one. + +Meanwhile for experimental drivers, use 65535 and work backwards. + + How many MSI-X vectors? + +Using the optional MSI-X capability devices can speed up +interrupt processing by removing the need to read ISR Status +register by guest driver (which might be an expensive operation), +reducing interrupt sharing between devices and queues within the +device, and handling interrupts from multiple CPUs. However, some +systems impose a limit (which might be as low as 256) on the +total number of MSI-X vectors that can be allocated to all +devices. Devices and/or device drivers should take this into +account, limiting the number of vectors used unless the device is +expected to cause a high volume of interrupts. Devices can +control the number of vectors used by limiting the MSI-X Table +Size or not presenting MSI-X capability in PCI configuration +space. Drivers can control this by mapping events to as small +number of vectors as possible, or disabling MSI-X capability +altogether. + + Message Framing + +The descriptors used for a buffer should not effect the semantics +of the message, except for the total length of the buffer. For +example, a network buffer consists of a 10 byte header followed +by the network packet. Whether this is presented in the ring +descriptor chain as (say) a 10 byte buffer and a 1514 byte +buffer, or a single 1524 byte buffer, or even three buffers, +should have no effect. + +In particular, no implementation should use the descriptor +boundaries to determine the size of any header in a request.[footnote: +The current qemu device implementations mistakenly insist that +the first descriptor cover the header in these cases exactly, so +a cautious driver should arrange it so. +] + + Device Improvements + +Any change to configuration space, or new virtqueues, or +behavioural changes, should be indicated by negotiation of a new +feature bit. This establishes clarity[footnote: +Even if it does mean documenting design or implementation +mistakes! +] and avoids future expansion problems. + +Clusters of functionality which are always implemented together +can use a single bit, but if one feature makes sense without the +others they should not be gratuitously grouped together to +conserve feature bits. We can always extend the spec when the +first person needs more than 24 feature bits for their device. + +[LaTeX Command: printnomenclature] + +Appendix A: virtio_ring.h + +#ifndef VIRTIO_RING_H + +#define VIRTIO_RING_H + +/* An interface for efficient virtio implementation. + + * + + * This header is BSD licensed so anyone can use the definitions + + * to implement compatible drivers/servers. + + * + + * Copyright 2007, 2009, IBM Corporation + + * Copyright 2011, Red Hat, Inc + + * All rights reserved. + + * + + * Redistribution and use in source and binary forms, with or +without + + * modification, are permitted provided that the following +conditions + + * are met: + + * 1. Redistributions of source code must retain the above +copyright + + * notice, this list of conditions and the following +disclaimer. + + * 2. Redistributions in binary form must reproduce the above +copyright + + * notice, this list of conditions and the following +disclaimer in the + + * documentation and/or other materials provided with the +distribution. + + * 3. Neither the name of IBM nor the names of its contributors + + * may be used to endorse or promote products derived from +this software + + * without specific prior written permission. + + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND +CONTRIBUTORS ``AS IS'' AND + + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED +TO, THE + + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +PARTICULAR PURPOSE + + * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE +LIABLE + + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +CONSEQUENTIAL + + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +SUBSTITUTE GOODS + + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +INTERRUPTION) + + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +CONTRACT, STRICT + + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING +IN ANY WAY + + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +POSSIBILITY OF + + * SUCH DAMAGE. + + */ + + + +/* This marks a buffer as continuing via the next field. */ + +#define VRING_DESC_F_NEXT 1 + +/* This marks a buffer as write-only (otherwise read-only). */ + +#define VRING_DESC_F_WRITE 2 + + + +/* The Host uses this in used->flags to advise the Guest: don't +kick me + + * when you add a buffer. It's unreliable, so it's simply an + + * optimization. Guest will still kick if it's out of buffers. +*/ + +#define VRING_USED_F_NO_NOTIFY 1 + +/* The Guest uses this in avail->flags to advise the Host: don't + + * interrupt me when you consume a buffer. It's unreliable, so +it's + + * simply an optimization. */ + +#define VRING_AVAIL_F_NO_INTERRUPT 1 + + + +/* Virtio ring descriptors: 16 bytes. + + * These can chain together via "next". */ + +struct vring_desc { + + /* Address (guest-physical). */ + + uint64_t addr; + + /* Length. */ + + uint32_t len; + + /* The flags as indicated above. */ + + uint16_t flags; + + /* We chain unused descriptors via this, too */ + + uint16_t next; + +}; + + + +struct vring_avail { + + uint16_t flags; + + uint16_t idx; + + uint16_t ring[]; + + uint16_t used_event; + +}; + + + +/* u32 is used here for ids for padding reasons. */ + +struct vring_used_elem { + + /* Index of start of used descriptor chain. */ + + uint32_t id; + + /* Total length of the descriptor chain which was written +to. */ + + uint32_t len; + +}; + + + +struct vring_used { + + uint16_t flags; + + uint16_t idx; + + struct vring_used_elem ring[]; + + uint16_t avail_event; + +}; + + + +struct vring { + + unsigned int num; + + + + struct vring_desc *desc; + + struct vring_avail *avail; + + struct vring_used *used; + +}; + + + +/* The standard layout for the ring is a continuous chunk of +memory which + + * looks like this. We assume num is a power of 2. + + * + + * struct vring { + + * // The actual descriptors (16 bytes each) + + * struct vring_desc desc[num]; + + * + + * // A ring of available descriptor heads with free-running +index. + + * __u16 avail_flags; + + * __u16 avail_idx; + + * __u16 available[num]; + + * + + * // Padding to the next align boundary. + + * char pad[]; + + * + + * // A ring of used descriptor heads with free-running +index. + + * __u16 used_flags; + + * __u16 EVENT_IDX; + + * struct vring_used_elem used[num]; + + * }; + + * Note: for virtio PCI, align is 4096. + + */ + +static inline void vring_init(struct vring *vr, unsigned int num, +void *p, + + unsigned long align) + +{ + + vr->num = num; + + vr->desc = p; + + vr->avail = p + num*sizeof(struct vring_desc); + + vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + + + align-1) + + & ~(align - 1)); + +} + + + +static inline unsigned vring_size(unsigned int num, unsigned long +align) + +{ + + return ((sizeof(struct vring_desc)*num + +sizeof(uint16_t)*(2+num) + + + align - 1) & ~(align - 1)) + + + sizeof(uint16_t)*3 + sizeof(struct +vring_used_elem)*num; + +} + + + +static inline int vring_need_event(uint16_t event_idx, uint16_t +new_idx, uint16_t old_idx) + +{ + + return (uint16_t)(new_idx - event_idx - 1) < +(uint16_t)(new_idx - old_idx); + +} + +#endif /* VIRTIO_RING_H */ + +<cha:Reserved-Feature-Bits>Appendix B: Reserved Feature Bits + +Currently there are five device-independent feature bits defined: + + VIRTIO_F_NOTIFY_ON_EMPTY (24) Negotiating this feature + indicates that the driver wants an interrupt if the device runs + out of available descriptors on a virtqueue, even though + interrupts are suppressed using the VRING_AVAIL_F_NO_INTERRUPT + flag or the used_event field. An example of this is the + networking driver: it doesn't need to know every time a packet + is transmitted, but it does need to free the transmitted + packets a finite time after they are transmitted. It can avoid + using a timer if the device interrupts it when all the packets + are transmitted. + + VIRTIO_F_RING_INDIRECT_DESC (28) Negotiating this feature + indicates that the driver can use descriptors with the + VRING_DESC_F_INDIRECT flag set, as described in [sub:Indirect-Descriptors] + . + + VIRTIO_F_RING_EVENT_IDX(29) This feature enables the used_event + and the avail_event fields. If set, it indicates that the + device should ignore the flags field in the available ring + structure. Instead, the used_event field in this structure is + used by guest to suppress device interrupts. Further, the + driver should ignore the flags field in the used ring + structure. Instead, the avail_event field in this structure is + used by the device to suppress notifications. If unset, the + driver should ignore the used_event field; the device should + ignore the avail_event field; the flags field is used + + VIRTIO_F_BAD_FEATURE(30) This feature should never be + negotiated by the guest; doing so is an indication that the + guest is faulty[footnote: +An experimental virtio PCI driver contained in Linux version +2.6.25 had this problem, and this feature bit can be used to +detect it. +] + + VIRTIO_F_FEATURES_HIGH(31) This feature indicates that the + device supports feature bits 32:63. If unset, feature bits + 32:63 are unset. + +Appendix C: Network Device + +The virtio network device is a virtual ethernet card, and is the +most complex of the devices supported so far by virtio. It has +enhanced rapidly and demonstrates clearly how support for new +features should be added to an existing device. Empty buffers are +placed in one virtqueue for receiving packets, and outgoing +packets are enqueued into another for transmission in that order. +A third command queue is used to control advanced filtering +features. + + Configuration + + Subsystem Device ID 1 + + Virtqueues 0:receiveq. 1:transmitq. 2:controlq[footnote: +Only if VIRTIO_NET_F_CTRL_VQ set +] + + Feature bits + + VIRTIO_NET_F_CSUM (0) Device handles packets with partial + checksum + + VIRTIO_NET_F_GUEST_CSUM (1) Guest handles packets with partial + checksum + + VIRTIO_NET_F_MAC (5) Device has given MAC address. + + VIRTIO_NET_F_GSO (6) (Deprecated) device handles packets with + any GSO type.[footnote: +It was supposed to indicate segmentation offload support, but +upon further investigation it became clear that multiple bits +were required. +] + + VIRTIO_NET_F_GUEST_TSO4 (7) Guest can receive TSOv4. + + VIRTIO_NET_F_GUEST_TSO6 (8) Guest can receive TSOv6. + + VIRTIO_NET_F_GUEST_ECN (9) Guest can receive TSO with ECN. + + VIRTIO_NET_F_GUEST_UFO (10) Guest can receive UFO. + + VIRTIO_NET_F_HOST_TSO4 (11) Device can receive TSOv4. + + VIRTIO_NET_F_HOST_TSO6 (12) Device can receive TSOv6. + + VIRTIO_NET_F_HOST_ECN (13) Device can receive TSO with ECN. + + VIRTIO_NET_F_HOST_UFO (14) Device can receive UFO. + + VIRTIO_NET_F_MRG_RXBUF (15) Guest can merge receive buffers. + + VIRTIO_NET_F_STATUS (16) Configuration status field is + available. + + VIRTIO_NET_F_CTRL_VQ (17) Control channel is available. + + VIRTIO_NET_F_CTRL_RX (18) Control channel RX mode support. + + VIRTIO_NET_F_CTRL_VLAN (19) Control channel VLAN filtering. + + Device configuration layout Two configuration fields are + currently defined. The mac address field always exists (though + is only valid if VIRTIO_NET_F_MAC is set), and the status field + only exists if VIRTIO_NET_F_STATUS is set. Only one bit is + currently defined for the status field: VIRTIO_NET_S_LINK_UP. #define VIRTIO_NET_S_LINK_UP 1 + + + +struct virtio_net_config { + + u8 mac[6]; + + u16 status; + +}; + + Device Initialization + + The initialization routine should identify the receive and + transmission virtqueues. + + If the VIRTIO_NET_F_MAC feature bit is set, the configuration + space “mac” entry indicates the “physical” address of the the + network card, otherwise a private MAC address should be + assigned. All guests are expected to negotiate this feature if + it is set. + + If the VIRTIO_NET_F_CTRL_VQ feature bit is negotiated, identify + the control virtqueue. + + If the VIRTIO_NET_F_STATUS feature bit is negotiated, the link + status can be read from the bottom bit of the “status” config + field. Otherwise, the link should be assumed active. + + The receive virtqueue should be filled with receive buffers. + This is described in detail below in “Setting Up Receive + Buffers”. + + A driver can indicate that it will generate checksumless + packets by negotating the VIRTIO_NET_F_CSUM feature. This “ + checksum offload” is a common feature on modern network cards. + + If that feature is negotiated, a driver can use TCP or UDP + segmentation offload by negotiating the VIRTIO_NET_F_HOST_TSO4 + (IPv4 TCP), VIRTIO_NET_F_HOST_TSO6 (IPv6 TCP) and + VIRTIO_NET_F_HOST_UFO (UDP fragmentation) features. It should + not send TCP packets requiring segmentation offload which have + the Explicit Congestion Notification bit set, unless the + VIRTIO_NET_F_HOST_ECN feature is negotiated.[footnote: +This is a common restriction in real, older network cards. +] + + The converse features are also available: a driver can save the + virtual device some work by negotiating these features.[footnote: +For example, a network packet transported between two guests on +the same system may not require checksumming at all, nor +segmentation, if both guests are amenable. +] The VIRTIO_NET_F_GUEST_CSUM feature indicates that partially + checksummed packets can be received, and if it can do that then + the VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, + VIRTIO_NET_F_GUEST_UFO and VIRTIO_NET_F_GUEST_ECN are the input + equivalents of the features described above. See “Receiving + Packets” below. + + Device Operation + +Packets are transmitted by placing them in the transmitq, and +buffers for incoming packets are placed in the receiveq. In each +case, the packet itself is preceeded by a header: + +struct virtio_net_hdr { + +#define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 + + u8 flags; + +#define VIRTIO_NET_HDR_GSO_NONE 0 + +#define VIRTIO_NET_HDR_GSO_TCPV4 1 + +#define VIRTIO_NET_HDR_GSO_UDP 3 + +#define VIRTIO_NET_HDR_GSO_TCPV6 4 + +#define VIRTIO_NET_HDR_GSO_ECN 0x80 + + u8 gso_type; + + u16 hdr_len; + + u16 gso_size; + + u16 csum_start; + + u16 csum_offset; + +/* Only if VIRTIO_NET_F_MRG_RXBUF: */ + + u16 num_buffers + +}; + +The controlq is used to control device features such as +filtering. + + Packet Transmission + +Transmitting a single packet is simple, but varies depending on +the different features the driver negotiated. + + If the driver negotiated VIRTIO_NET_F_CSUM, and the packet has + not been fully checksummed, then the virtio_net_hdr's fields + are set as follows. Otherwise, the packet must be fully + checksummed, and flags is zero. + + flags has the VIRTIO_NET_HDR_F_NEEDS_CSUM set, + + <ite:csum_start-is-set>csum_start is set to the offset within + the packet to begin checksumming, and + + csum_offset indicates how many bytes after the csum_start the + new (16 bit ones' complement) checksum should be placed.[footnote: +For example, consider a partially checksummed TCP (IPv4) packet. +It will have a 14 byte ethernet header and 20 byte IP header +followed by the TCP header (with the TCP checksum field 16 bytes +into that header). csum_start will be 14+20 = 34 (the TCP +checksum includes the header), and csum_offset will be 16. The +value in the TCP checksum field will be the sum of the TCP pseudo +header, so that replacing it by the ones' complement checksum of +the TCP header and body will give the correct result. +] + + <enu:If-the-driver>If the driver negotiated + VIRTIO_NET_F_HOST_TSO4, TSO6 or UFO, and the packet requires + TCP segmentation or UDP fragmentation, then the “gso_type” + field is set to VIRTIO_NET_HDR_GSO_TCPV4, TCPV6 or UDP. + (Otherwise, it is set to VIRTIO_NET_HDR_GSO_NONE). In this + case, packets larger than 1514 bytes can be transmitted: the + metadata indicates how to replicate the packet header to cut it + into smaller packets. The other gso fields are set: + + hdr_len is a hint to the device as to how much of the header + needs to be kept to copy into each packet, usually set to the + length of the headers, including the transport header.[footnote: +Due to various bugs in implementations, this field is not useful +as a guarantee of the transport header size. +] + + gso_size is the size of the packet beyond that header (ie. + MSS). + + If the driver negotiated the VIRTIO_NET_F_HOST_ECN feature, the + VIRTIO_NET_HDR_GSO_ECN bit may be set in “gso_type” as well, + indicating that the TCP packet has the ECN bit set.[footnote: +This case is not handled by some older hardware, so is called out +specifically in the protocol. +] + + If the driver negotiated the VIRTIO_NET_F_MRG_RXBUF feature, + the num_buffers field is set to zero. + + The header and packet are added as one output buffer to the + transmitq, and the device is notified of the new entry (see [sub:Notifying-The-Device] + ).[footnote: +Note that the header will be two bytes longer for the +VIRTIO_NET_F_MRG_RXBUF case. +] + + Packet Transmission Interrupt + +Often a driver will suppress transmission interrupts using the +VRING_AVAIL_F_NO_INTERRUPT flag (see [sub:Receiving-Used-Buffers] +) and check for used packets in the transmit path of following +packets. However, it will still receive interrupts if the +VIRTIO_F_NOTIFY_ON_EMPTY feature is negotiated, indicating that +the transmission queue is completely emptied. + +The normal behavior in this interrupt handler is to retrieve and +new descriptors from the used ring and free the corresponding +headers and packets. + + Setting Up Receive Buffers + +It is generally a good idea to keep the receive virtqueue as +fully populated as possible: if it runs out, network performance +will suffer. + +If the VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6 or +VIRTIO_NET_F_GUEST_UFO features are used, the Guest will need to +accept packets of up to 65550 bytes long (the maximum size of a +TCP or UDP packet, plus the 14 byte ethernet header), otherwise +1514 bytes. So unless VIRTIO_NET_F_MRG_RXBUF is negotiated, every +buffer in the receive queue needs to be at least this length [footnote: +Obviously each one can be split across multiple descriptor +elements. +]. + +If VIRTIO_NET_F_MRG_RXBUF is negotiated, each buffer must be at +least the size of the struct virtio_net_hdr. + + Packet Receive Interrupt + +When a packet is copied into a buffer in the receiveq, the +optimal path is to disable further interrupts for the receiveq +(see [sub:Receiving-Used-Buffers]) and process packets until no +more are found, then re-enable them. + +Processing packet involves: + + If the driver negotiated the VIRTIO_NET_F_MRG_RXBUF feature, + then the “num_buffers” field indicates how many descriptors + this packet is spread over (including this one). This allows + receipt of large packets without having to allocate large + buffers. In this case, there will be at least “num_buffers” in + the used ring, and they should be chained together to form a + single packet. The other buffers will not begin with a struct + virtio_net_hdr. + + If the VIRTIO_NET_F_MRG_RXBUF feature was not negotiated, or + the “num_buffers” field is one, then the entire packet will be + contained within this buffer, immediately following the struct + virtio_net_hdr. + + If the VIRTIO_NET_F_GUEST_CSUM feature was negotiated, the + VIRTIO_NET_HDR_F_NEEDS_CSUM bit in the “flags” field may be + set: if so, the checksum on the packet is incomplete and the “ + csum_start” and “csum_offset” fields indicate how to calculate + it (see [ite:csum_start-is-set]). + + If the VIRTIO_NET_F_GUEST_TSO4, TSO6 or UFO options were + negotiated, then the “gso_type” may be something other than + VIRTIO_NET_HDR_GSO_NONE, and the “gso_size” field indicates the + desired MSS (see [enu:If-the-driver]).Control Virtqueue + +The driver uses the control virtqueue (if VIRTIO_NET_F_VTRL_VQ is +negotiated) to send commands to manipulate various features of +the device which would not easily map into the configuration +space. + +All commands are of the following form: + +struct virtio_net_ctrl { + + u8 class; + + u8 command; + + u8 command-specific-data[]; + + u8 ack; + +}; + + + +/* ack values */ + +#define VIRTIO_NET_OK 0 + +#define VIRTIO_NET_ERR 1 + +The class, command and command-specific-data are set by the +driver, and the device sets the ack byte. There is little it can +do except issue a diagnostic if the ack byte is not +VIRTIO_NET_OK. + + Packet Receive Filtering + +If the VIRTIO_NET_F_CTRL_RX feature is negotiated, the driver can +send control commands for promiscuous mode, multicast receiving, +and filtering of MAC addresses. + +Note that in general, these commands are best-effort: unwanted +packets may still arrive. + + Setting Promiscuous Mode + +#define VIRTIO_NET_CTRL_RX 0 + + #define VIRTIO_NET_CTRL_RX_PROMISC 0 + + #define VIRTIO_NET_CTRL_RX_ALLMULTI 1 + +The class VIRTIO_NET_CTRL_RX has two commands: +VIRTIO_NET_CTRL_RX_PROMISC turns promiscuous mode on and off, and +VIRTIO_NET_CTRL_RX_ALLMULTI turns all-multicast receive on and +off. The command-specific-data is one byte containing 0 (off) or +1 (on). + + Setting MAC Address Filtering + +struct virtio_net_ctrl_mac { + + u32 entries; + + u8 macs[entries][ETH_ALEN]; + +}; + + + +#define VIRTIO_NET_CTRL_MAC 1 + + #define VIRTIO_NET_CTRL_MAC_TABLE_SET 0 + +The device can filter incoming packets by any number of +destination MAC addresses.[footnote: +Since there are no guarentees, it can use a hash filter +orsilently switch to allmulti or promiscuous mode if it is given +too many addresses. +] This table is set using the class VIRTIO_NET_CTRL_MAC and the +command VIRTIO_NET_CTRL_MAC_TABLE_SET. The command-specific-data +is two variable length tables of 6-byte MAC addresses. The first +table contains unicast addresses, and the second contains +multicast addresses. + + VLAN Filtering + +If the driver negotiates the VIRTION_NET_F_CTRL_VLAN feature, it +can control a VLAN filter table in the device. + +#define VIRTIO_NET_CTRL_VLAN 2 + + #define VIRTIO_NET_CTRL_VLAN_ADD 0 + + #define VIRTIO_NET_CTRL_VLAN_DEL 1 + +Both the VIRTIO_NET_CTRL_VLAN_ADD and VIRTIO_NET_CTRL_VLAN_DEL +command take a 16-bit VLAN id as the command-specific-data. + +Appendix D: Block Device + +The virtio block device is a simple virtual block device (ie. +disk). Read and write requests (and other exotic requests) are +placed in the queue, and serviced (probably out of order) by the +device except where noted. + + Configuration + + Subsystem Device ID 2 + + Virtqueues 0:requestq. + + Feature bits + + VIRTIO_BLK_F_BARRIER (0) Host supports request barriers. + + VIRTIO_BLK_F_SIZE_MAX (1) Maximum size of any single segment is + in “size_max”. + + VIRTIO_BLK_F_SEG_MAX (2) Maximum number of segments in a + request is in “seg_max”. + + VIRTIO_BLK_F_GEOMETRY (4) Disk-style geometry specified in “ + geometry”. + + VIRTIO_BLK_F_RO (5) Device is read-only. + + VIRTIO_BLK_F_BLK_SIZE (6) Block size of disk is in “blk_size”. + + VIRTIO_BLK_F_SCSI (7) Device supports scsi packet commands. + + VIRTIO_BLK_F_FLUSH (9) Cache flush command support. + + + + Device configuration layout The capacity of the device + (expressed in 512-byte sectors) is always present. The + availability of the others all depend on various feature bits + as indicated above. struct virtio_blk_config { + + u64 capacity; + + u32 size_max; + + u32 seg_max; + + struct virtio_blk_geometry { + + u16 cylinders; + + u8 heads; + + u8 sectors; + + } geometry; + + u32 blk_size; + + + +}; + + Device Initialization + + The device size should be read from the “capacity” + configuration field. No requests should be submitted which goes + beyond this limit. + + If the VIRTIO_BLK_F_BLK_SIZE feature is negotiated, the + blk_size field can be read to determine the optimal sector size + for the driver to use. This does not effect the units used in + the protocol (always 512 bytes), but awareness of the correct + value can effect performance. + + If the VIRTIO_BLK_F_RO feature is set by the device, any write + requests will fail. + + + + Device Operation + +The driver queues requests to the virtqueue, and they are used by +the device (not necessarily in order). Each request is of form: + +struct virtio_blk_req { + + + + u32 type; + + u32 ioprio; + + u64 sector; + + char data[][512]; + + u8 status; + +}; + +If the device has VIRTIO_BLK_F_SCSI feature, it can also support +scsi packet command requests, each of these requests is of form:struct virtio_scsi_pc_req { + + u32 type; + + u32 ioprio; + + u64 sector; + + char cmd[]; + + char data[][512]; + +#define SCSI_SENSE_BUFFERSIZE 96 + + u8 sense[SCSI_SENSE_BUFFERSIZE]; + + u32 errors; + + u32 data_len; + + u32 sense_len; + + u32 residual; + + u8 status; + +}; + +The type of the request is either a read (VIRTIO_BLK_T_IN), a +write (VIRTIO_BLK_T_OUT), a scsi packet command +(VIRTIO_BLK_T_SCSI_CMD or VIRTIO_BLK_T_SCSI_CMD_OUT[footnote: +the SCSI_CMD and SCSI_CMD_OUT types are equivalent, the device +does not distinguish between them +]) or a flush (VIRTIO_BLK_T_FLUSH or VIRTIO_BLK_T_FLUSH_OUT[footnote: +the FLUSH and FLUSH_OUT types are equivalent, the device does not +distinguish between them +]). If the device has VIRTIO_BLK_F_BARRIER feature the high bit +(VIRTIO_BLK_T_BARRIER) indicates that this request acts as a +barrier and that all preceeding requests must be complete before +this one, and all following requests must not be started until +this is complete. Note that a barrier does not flush caches in +the underlying backend device in host, and thus does not serve as +data consistency guarantee. Driver must use FLUSH request to +flush the host cache. + +#define VIRTIO_BLK_T_IN 0 + +#define VIRTIO_BLK_T_OUT 1 + +#define VIRTIO_BLK_T_SCSI_CMD 2 + +#define VIRTIO_BLK_T_SCSI_CMD_OUT 3 + +#define VIRTIO_BLK_T_FLUSH 4 + +#define VIRTIO_BLK_T_FLUSH_OUT 5 + +#define VIRTIO_BLK_T_BARRIER 0x80000000 + +The ioprio field is a hint about the relative priorities of +requests to the device: higher numbers indicate more important +requests. + +The sector number indicates the offset (multiplied by 512) where +the read or write is to occur. This field is unused and set to 0 +for scsi packet commands and for flush commands. + +The cmd field is only present for scsi packet command requests, +and indicates the command to perform. This field must reside in a +single, separate read-only buffer; command length can be derived +from the length of this buffer. + +Note that these first three (four for scsi packet commands) +fields are always read-only: the data field is either read-only +or write-only, depending on the request. The size of the read or +write can be derived from the total size of the request buffers. + +The sense field is only present for scsi packet command requests, +and indicates the buffer for scsi sense data. + +The data_len field is only present for scsi packet command +requests, this field is deprecated, and should be ignored by the +driver. Historically, devices copied data length there. + +The sense_len field is only present for scsi packet command +requests and indicates the number of bytes actually written to +the sense buffer. + +The residual field is only present for scsi packet command +requests and indicates the residual size, calculated as data +length - number of bytes actually transferred. + +The final status byte is written by the device: either +VIRTIO_BLK_S_OK for success, VIRTIO_BLK_S_IOERR for host or guest +error or VIRTIO_BLK_S_UNSUPP for a request unsupported by host:#define VIRTIO_BLK_S_OK 0 + +#define VIRTIO_BLK_S_IOERR 1 + +#define VIRTIO_BLK_S_UNSUPP 2 + +Historically, devices assumed that the fields type, ioprio and +sector reside in a single, separate read-only buffer; the fields +errors, data_len, sense_len and residual reside in a single, +separate write-only buffer; the sense field in a separate +write-only buffer of size 96 bytes, by itself; the fields errors, +data_len, sense_len and residual in a single write-only buffer; +and the status field is a separate read-only buffer of size 1 +byte, by itself. + +Appendix E: Console Device + +The virtio console device is a simple device for data input and +output. A device may have one or more ports. Each port has a pair +of input and output virtqueues. Moreover, a device has a pair of +control IO virtqueues. The control virtqueues are used to +communicate information between the device and the driver about +ports being opened and closed on either side of the connection, +indication from the host about whether a particular port is a +console port, adding new ports, port hot-plug/unplug, etc., and +indication from the guest about whether a port or a device was +successfully added, port open/close, etc.. For data IO, one or +more empty buffers are placed in the receive queue for incoming +data and outgoing characters are placed in the transmit queue. + + Configuration + + Subsystem Device ID 3 + + Virtqueues 0:receiveq(port0). 1:transmitq(port0), 2:control + receiveq[footnote: +Ports 2 onwards only if VIRTIO_CONSOLE_F_MULTIPORT is set +], 3:control transmitq, 4:receiveq(port1), 5:transmitq(port1), + ... + + Feature bits + + VIRTIO_CONSOLE_F_SIZE (0) Configuration cols and rows fields + are valid. + + VIRTIO_CONSOLE_F_MULTIPORT(1) Device has support for multiple + ports; configuration fields nr_ports and max_nr_ports are + valid and control virtqueues will be used. + + Device configuration layout The size of the console is supplied + in the configuration space if the VIRTIO_CONSOLE_F_SIZE feature + is set. Furthermore, if the VIRTIO_CONSOLE_F_MULTIPORT feature + is set, the maximum number of ports supported by the device can + be fetched.struct virtio_console_config { + + u16 cols; + + u16 rows; + + + + u32 max_nr_ports; + +}; + + Device Initialization + + If the VIRTIO_CONSOLE_F_SIZE feature is negotiated, the driver + can read the console dimensions from the configuration fields. + + If the VIRTIO_CONSOLE_F_MULTIPORT feature is negotiated, the + driver can spawn multiple ports, not all of which may be + attached to a console. Some could be generic ports. In this + case, the control virtqueues are enabled and according to the + max_nr_ports configuration-space value, the appropriate number + of virtqueues are created. A control message indicating the + driver is ready is sent to the host. The host can then send + control messages for adding new ports to the device. After + creating and initializing each port, a + VIRTIO_CONSOLE_PORT_READY control message is sent to the host + for that port so the host can let us know of any additional + configuration options set for that port. + + The receiveq for each port is populated with one or more + receive buffers. + + Device Operation + + For output, a buffer containing the characters is placed in the + port's transmitq.[footnote: +Because this is high importance and low bandwidth, the current +Linux implementation polls for the buffer to be used, rather than +waiting for an interrupt, simplifying the implementation +significantly. However, for generic serial ports with the +O_NONBLOCK flag set, the polling limitation is relaxed and the +consumed buffers are freed upon the next write or poll call or +when a port is closed or hot-unplugged. +] + + When a buffer is used in the receiveq (signalled by an + interrupt), the contents is the input to the port associated + with the virtqueue for which the notification was received. + + If the driver negotiated the VIRTIO_CONSOLE_F_SIZE feature, a + configuration change interrupt may occur. The updated size can + be read from the configuration fields. + + If the driver negotiated the VIRTIO_CONSOLE_F_MULTIPORT + feature, active ports are announced by the host using the + VIRTIO_CONSOLE_PORT_ADD control message. The same message is + used for port hot-plug as well. + + If the host specified a port `name', a sysfs attribute is + created with the name filled in, so that udev rules can be + written that can create a symlink from the port's name to the + char device for port discovery by applications in the guest. + + Changes to ports' state are effected by control messages. + Appropriate action is taken on the port indicated in the + control message. The layout of the structure of the control + buffer and the events associated are:struct virtio_console_control { + + uint32_t id; /* Port number */ + + uint16_t event; /* The kind of control event */ + + uint16_t value; /* Extra information for the event */ + +}; + + + +/* Some events for the internal messages (control packets) */ + + + +#define VIRTIO_CONSOLE_DEVICE_READY 0 + +#define VIRTIO_CONSOLE_PORT_ADD 1 + +#define VIRTIO_CONSOLE_PORT_REMOVE 2 + +#define VIRTIO_CONSOLE_PORT_READY 3 + +#define VIRTIO_CONSOLE_CONSOLE_PORT 4 + +#define VIRTIO_CONSOLE_RESIZE 5 + +#define VIRTIO_CONSOLE_PORT_OPEN 6 + +#define VIRTIO_CONSOLE_PORT_NAME 7 + +Appendix F: Entropy Device + +The virtio entropy device supplies high-quality randomness for +guest use. + + Configuration + + Subsystem Device ID 4 + + Virtqueues 0:requestq. + + Feature bits None currently defined + + Device configuration layout None currently defined. + + Device Initialization + + The virtqueue is initialized + + Device Operation + +When the driver requires random bytes, it places the descriptor +of one or more buffers in the queue. It will be completely filled +by random data by the device. + +Appendix G: Memory Balloon Device + +The virtio memory balloon device is a primitive device for +managing guest memory: the device asks for a certain amount of +memory, and the guest supplies it (or withdraws it, if the device +has more than it asks for). This allows the guest to adapt to +changes in allowance of underlying physical memory. If the +feature is negotiated, the device can also be used to communicate +guest memory statistics to the host. + + Configuration + + Subsystem Device ID 5 + + Virtqueues 0:inflateq. 1:deflateq. 2:statsq.[footnote: +Only if VIRTIO_BALLON_F_STATS_VQ set +] + + Feature bits + + VIRTIO_BALLOON_F_MUST_TELL_HOST (0) Host must be told before + pages from the balloon are used. + + VIRTIO_BALLOON_F_STATS_VQ (1) A virtqueue for reporting guest + memory statistics is present. + + Device configuration layout Both fields of this configuration + are always available. Note that they are little endian, despite + convention that device fields are guest endian:struct virtio_balloon_config { + + u32 num_pages; + + u32 actual; + +}; + + Device Initialization + + The inflate and deflate virtqueues are identified. + + If the VIRTIO_BALLOON_F_STATS_VQ feature bit is negotiated: + + Identify the stats virtqueue. + + Add one empty buffer to the stats virtqueue and notify the + host. + +Device operation begins immediately. + + Device Operation + + Memory Ballooning The device is driven by the receipt of a + configuration change interrupt. + + The “num_pages” configuration field is examined. If this is + greater than the “actual” number of pages, memory must be given + to the balloon. If it is less than the “actual” number of + pages, memory may be taken back from the balloon for general + use. + + To supply memory to the balloon (aka. inflate): + + The driver constructs an array of addresses of unused memory + pages. These addresses are divided by 4096[footnote: +This is historical, and independent of the guest page size +] and the descriptor describing the resulting 32-bit array is + added to the inflateq. + + To remove memory from the balloon (aka. deflate): + + The driver constructs an array of addresses of memory pages it + has previously given to the balloon, as described above. This + descriptor is added to the deflateq. + + If the VIRTIO_BALLOON_F_MUST_TELL_HOST feature is set, the + guest may not use these requested pages until that descriptor + in the deflateq has been used by the device. + + Otherwise, the guest may begin to re-use pages previously given + to the balloon before the device has acknowledged their + withdrawl. [footnote: +In this case, deflation advice is merely a courtesy +] + + In either case, once the device has completed the inflation or + deflation, the “actual” field of the configuration should be + updated to reflect the new number of pages in the balloon.[footnote: +As updates to configuration space are not atomic, this field +isn't particularly reliable, but can be used to diagnose buggy +guests. +] + + Memory Statistics + +The stats virtqueue is atypical because communication is driven +by the device (not the driver). The channel becomes active at +driver initialization time when the driver adds an empty buffer +and notifies the device. A request for memory statistics proceeds +as follows: + + The device pushes the buffer onto the used ring and sends an + interrupt. + + The driver pops the used buffer and discards it. + + The driver collects memory statistics and writes them into a + new buffer. + + The driver adds the buffer to the virtqueue and notifies the + device. + + The device pops the buffer (retaining it to initiate a + subsequent request) and consumes the statistics. + + Memory Statistics Format Each statistic consists of a 16 bit + tag and a 64 bit value. Both quantities are represented in the + native endian of the guest. All statistics are optional and the + driver may choose which ones to supply. To guarantee backwards + compatibility, unsupported statistics should be omitted. + + struct virtio_balloon_stat { + +#define VIRTIO_BALLOON_S_SWAP_IN 0 + +#define VIRTIO_BALLOON_S_SWAP_OUT 1 + +#define VIRTIO_BALLOON_S_MAJFLT 2 + +#define VIRTIO_BALLOON_S_MINFLT 3 + +#define VIRTIO_BALLOON_S_MEMFREE 4 + +#define VIRTIO_BALLOON_S_MEMTOT 5 + + u16 tag; + + u64 val; + +} __attribute__((packed)); + + Tags + + VIRTIO_BALLOON_S_SWAP_IN The amount of memory that has been + swapped in (in bytes). + + VIRTIO_BALLOON_S_SWAP_OUT The amount of memory that has been + swapped out to disk (in bytes). + + VIRTIO_BALLOON_S_MAJFLT The number of major page faults that + have occurred. + + VIRTIO_BALLOON_S_MINFLT The number of minor page faults that + have occurred. + + VIRTIO_BALLOON_S_MEMFREE The amount of memory not being used + for any purpose (in bytes). + + VIRTIO_BALLOON_S_MEMTOT The total amount of memory available + (in bytes). + diff --git a/Documentation/vm/00-INDEX b/Documentation/vm/00-INDEX index dca82d7c83d..5481c8ba341 100644 --- a/Documentation/vm/00-INDEX +++ b/Documentation/vm/00-INDEX @@ -30,8 +30,6 @@ page_migration - description of page migration in NUMA systems. pagemap.txt - pagemap, from the userspace perspective -slabinfo.c - - source code for a tool to get reports about slabs. slub.txt - a short users guide for SLUB. unevictable-lru.txt diff --git a/Documentation/vm/numa b/Documentation/vm/numa index a200a386429..ade01274212 100644 --- a/Documentation/vm/numa +++ b/Documentation/vm/numa @@ -109,11 +109,11 @@ to improve NUMA locality using various CPU affinity command line interfaces, such as taskset(1) and numactl(1), and program interfaces such as sched_setaffinity(2). Further, one can modify the kernel's default local allocation behavior using Linux NUMA memory policy. -[see Documentation/vm/numa_memory_policy.] +[see Documentation/vm/numa_memory_policy.txt.] System administrators can restrict the CPUs and nodes' memories that a non- privileged user can specify in the scheduling or NUMA commands and functions -using control groups and CPUsets. [see Documentation/cgroups/CPUsets.txt] +using control groups and CPUsets. [see Documentation/cgroups/cpusets.txt] On architectures that do not hide memoryless nodes, Linux will include only zones [nodes] with memory in the zonelists. This means that for a memoryless diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt index 07375e73981..f464f47bc60 100644 --- a/Documentation/vm/slub.txt +++ b/Documentation/vm/slub.txt @@ -17,7 +17,7 @@ data and perform operation on the slabs. By default slabinfo only lists slabs that have data in them. See "slabinfo -h" for more options when running the command. slabinfo can be compiled with -gcc -o slabinfo Documentation/vm/slabinfo.c +gcc -o slabinfo tools/slub/slabinfo.c Some of the modes of operation of slabinfo require that slub debugging be enabled on the command line. F.e. no tracking information will be diff --git a/Documentation/vm/transhuge.txt b/Documentation/vm/transhuge.txt index 0924aaca330..29bdf62aac0 100644 --- a/Documentation/vm/transhuge.txt +++ b/Documentation/vm/transhuge.txt @@ -123,10 +123,11 @@ be automatically shutdown if it's set to "never". khugepaged runs usually at low frequency so while one may not want to invoke defrag algorithms synchronously during the page faults, it should be worth invoking defrag at least in khugepaged. However it's -also possible to disable defrag in khugepaged: +also possible to disable defrag in khugepaged by writing 0 or enable +defrag in khugepaged by writing 1: -echo yes >/sys/kernel/mm/transparent_hugepage/khugepaged/defrag -echo no >/sys/kernel/mm/transparent_hugepage/khugepaged/defrag +echo 0 >/sys/kernel/mm/transparent_hugepage/khugepaged/defrag +echo 1 >/sys/kernel/mm/transparent_hugepage/khugepaged/defrag You can also control how many pages khugepaged should scan at each pass: diff --git a/Documentation/zh_CN/SubmitChecklist b/Documentation/zh_CN/SubmitChecklist deleted file mode 100644 index 4c741d6bc04..00000000000 --- a/Documentation/zh_CN/SubmitChecklist +++ /dev/null @@ -1,109 +0,0 @@ -Chinese translated version of Documentation/SubmitChecklist - -If you have any comment or update to the content, please contact the -original document maintainer directly. However, if you have a problem -communicating in English you can also ask the Chinese maintainer for -help. Contact the Chinese maintainer if this translation is outdated -or if there is a problem with the translation. - -Chinese maintainer: Harry Wei <harryxiyou@gmail.com> ---------------------------------------------------------------------- -Documentation/SubmitChecklist ķ - -ۻ±ĵݣֱϵԭĵάߡʹӢ -ѵĻҲİά²ʱ߷ -⣬ϵİάߡ - -İάߣ Harry Wei <harryxiyou@gmail.com> -İ淭ߣ Harry Wei <harryxiyou@gmail.com> -İУߣ Harry Wei <harryxiyou@gmail.com> - - -Ϊ ---------------------------------------------------------------------- -Linuxںύ嵥 -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -һЩں˿ӦĻ飬뿴Լں˲ύ -ܵĸ졣 - -ЩdzDocumentation/SubmittingPatchesĵṩԼ -ύLinuxں˲˵ - -1ʹһô#include/ǸܵǸļ - Ҫ붨/Ǹܵͷļ - -2û߸CONFIGѡ =y=m=n - Ҫб뾯/ ҪӾ/ - -2bͨ allnoconfig, allmodconfig - -2cʹ 0=builddir ɹع - -3ͨʹñؽ빤һЩڶCPUϹ - -4ppc64 һܺõļ齻ĿܣΪѡunsigned long - 64λֵʹá - -5Documentation/CodingStyleļϸ㲹 - ʹòΥ(scripts/checkpatch.pl)Աύ - Ӧõ㲹еΥ档 - -6κθ»߸ĶCONFIGѡܴò˵ - -7еKconfigѡ¶Ҫ˵֡ - -8ѾܽصKconfigϡǺͨõ--½ - -9мԡ - -10ʹ'make checkstack''make namespacecheck'飬Ȼҵ⡣ - ע⣺ջ鲻ȷس⣬κεһڶջʹö512ֽ - Ҫġ - -11kernel-docȫںAPIsļҪ̬ĺǰҲν - ʹ'make htmldocs''make mandocs'kernel-docȻκ - ֵ⡣ - -12ѾͨCONFIG_PREEMPT, CONFIG_DEBUG_PREEMPT, - CONFIG_DEBUG_SLAB, CONFIG_DEBUG_PAGEALLOC, CONFIG_DEBUG_MUTEXES, - CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_ATOMIC_SLEEPԣͬʱ - ʹܡ - -13Ѿʹû߲ʹ CONFIG_SMP CONFIG_PREEMPTִʱ䡣 - -14ӰIO/DiskȵȣѾͨʹû߲ʹ CONFIG_LBDAF ԡ - -15еcodepathsѾʹlockdepùܡ - -16е/proc¼¶ҪļDocumentation/Ŀ¼¡ - -17еں¶¼Documentation/kernel-parameters.txtļС - -18еģ¶MODULE_PARM_DESC()¼ - -19еûռӿڸ¶¼Documentation/ABI/鿴Documentation/ABI/README - ԻøϢıûռӿڵIJӦñʼlinux-api@vger.kernel.org - -20DzǶͨ`make headers_check' - -21Ѿͨslabpage-allocationʧܼ顣鿴Documentation/fault-injection/ - -22¼ԴѾͨ`gcc -W'ʹ"make EXTRA_CFLAGS=-W"롣ܶෳգ - ǶѰ©洦:"warning: comparison between signed and unsigned" - -23ϲ-mmٲԣȷǷͲеһԼVMVFS - ϵͳи仯 - -24еڴ{e.g., barrier(), rmb(), wmb()}ҪԴеһעǶǸʲô - Լԭ - -25κƵIJӣҲҪDocumentation/ioctl/ioctl-number.txt - -26ĸĴʹκεںAPIskconfigйϵĹܣҪ - ʹصkconfigŹرգ and/or =mѡṩ[ͬһʱ䲻õĶã - ] - - CONFIG_SMP, CONFIG_SYSFS, CONFIG_PROC_FS, CONFIG_INPUT, CONFIG_PCI, - CONFIG_BLOCK, CONFIG_PM, CONFIG_HOTPLUG, CONFIG_MAGIC_SYSRQ, - CONFIG_NET, CONFIG_INET=n (һʹ CONFIG_NET=y) |