diff options
Diffstat (limited to 'include/linux/pm.h')
| -rw-r--r-- | include/linux/pm.h | 314 |
1 files changed, 286 insertions, 28 deletions
diff --git a/include/linux/pm.h b/include/linux/pm.h index 39a7ee859b6..4ad9de94449 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -112,7 +112,9 @@ typedef struct pm_message { int event; } pm_message_t; -/* +/** + * struct pm_ops - device PM callbacks + * * Several driver power state transitions are externally visible, affecting * the state of pending I/O queues and (for drivers that touch hardware) * interrupts, wakeups, DMA, and other hardware state. There may also be @@ -120,6 +122,284 @@ typedef struct pm_message { * to the rest of the driver stack (such as a driver that's ON gating off * clocks which are not in active use). * + * The externally visible transitions are handled with the help of the following + * callbacks included in this structure: + * + * @prepare: Prepare the device for the upcoming transition, but do NOT change + * its hardware state. Prevent new children of the device from being + * registered after @prepare() returns (the driver's subsystem and + * generally the rest of the kernel is supposed to prevent new calls to the + * probe method from being made too once @prepare() has succeeded). If + * @prepare() detects a situation it cannot handle (e.g. registration of a + * child already in progress), it may return -EAGAIN, so that the PM core + * can execute it once again (e.g. after the new child has been registered) + * to recover from the race condition. This method is executed for all + * kinds of suspend transitions and is followed by one of the suspend + * callbacks: @suspend(), @freeze(), or @poweroff(). + * The PM core executes @prepare() for all devices before starting to + * execute suspend callbacks for any of them, so drivers may assume all of + * the other devices to be present and functional while @prepare() is being + * executed. In particular, it is safe to make GFP_KERNEL memory + * allocations from within @prepare(). However, drivers may NOT assume + * anything about the availability of the user space at that time and it + * is not correct to request firmware from within @prepare() (it's too + * late to do that). [To work around this limitation, drivers may + * register suspend and hibernation notifiers that are executed before the + * freezing of tasks.] + * + * @complete: Undo the changes made by @prepare(). This method is executed for + * all kinds of resume transitions, following one of the resume callbacks: + * @resume(), @thaw(), @restore(). Also called if the state transition + * fails before the driver's suspend callback (@suspend(), @freeze(), + * @poweroff()) can be executed (e.g. if the suspend callback fails for one + * of the other devices that the PM core has unsuccessfully attempted to + * suspend earlier). + * The PM core executes @complete() after it has executed the appropriate + * resume callback for all devices. + * + * @suspend: Executed before putting the system into a sleep state in which the + * contents of main memory are preserved. Quiesce the device, put it into + * a low power state appropriate for the upcoming system state (such as + * PCI_D3hot), and enable wakeup events as appropriate. + * + * @resume: Executed after waking the system up from a sleep state in which the + * contents of main memory were preserved. Put the device into the + * appropriate state, according to the information saved in memory by the + * preceding @suspend(). The driver starts working again, responding to + * hardware events and software requests. The hardware may have gone + * through a power-off reset, or it may have maintained state from the + * previous suspend() which the driver may rely on while resuming. On most + * platforms, there are no restrictions on availability of resources like + * clocks during @resume(). + * + * @freeze: Hibernation-specific, executed before creating a hibernation image. + * Quiesce operations so that a consistent image can be created, but do NOT + * otherwise put the device into a low power device state and do NOT emit + * system wakeup events. Save in main memory the device settings to be + * used by @restore() during the subsequent resume from hibernation or by + * the subsequent @thaw(), if the creation of the image or the restoration + * of main memory contents from it fails. + * + * @thaw: Hibernation-specific, executed after creating a hibernation image OR + * if the creation of the image fails. Also executed after a failing + * attempt to restore the contents of main memory from such an image. + * Undo the changes made by the preceding @freeze(), so the device can be + * operated in the same way as immediately before the call to @freeze(). + * + * @poweroff: Hibernation-specific, executed after saving a hibernation image. + * Quiesce the device, put it into a low power state appropriate for the + * upcoming system state (such as PCI_D3hot), and enable wakeup events as + * appropriate. + * + * @restore: Hibernation-specific, executed after restoring the contents of main + * memory from a hibernation image. Driver starts working again, + * responding to hardware events and software requests. Drivers may NOT + * make ANY assumptions about the hardware state right prior to @restore(). + * On most platforms, there are no restrictions on availability of + * resources like clocks during @restore(). + * + * All of the above callbacks, except for @complete(), return error codes. + * However, the error codes returned by the resume operations, @resume(), + * @thaw(), and @restore(), do not cause the PM core to abort the resume + * transition during which they are returned. The error codes returned in + * that cases are only printed by the PM core to the system logs for debugging + * purposes. Still, it is recommended that drivers only return error codes + * from their resume methods in case of an unrecoverable failure (i.e. when the + * device being handled refuses to resume and becomes unusable) to allow us to + * modify the PM core in the future, so that it can avoid attempting to handle + * devices that failed to resume and their children. + * + * It is allowed to unregister devices while the above callbacks are being + * executed. However, it is not allowed to unregister a device from within any + * of its own callbacks. + */ + +struct pm_ops { + int (*prepare)(struct device *dev); + void (*complete)(struct device *dev); + int (*suspend)(struct device *dev); + int (*resume)(struct device *dev); + int (*freeze)(struct device *dev); + int (*thaw)(struct device *dev); + int (*poweroff)(struct device *dev); + int (*restore)(struct device *dev); +}; + +/** + * struct pm_ext_ops - extended device PM callbacks + * + * Some devices require certain operations related to suspend and hibernation + * to be carried out with interrupts disabled. Thus, 'struct pm_ext_ops' below + * is defined, adding callbacks to be executed with interrupts disabled to + * 'struct pm_ops'. + * + * The following callbacks included in 'struct pm_ext_ops' are executed with + * the nonboot CPUs switched off and with interrupts disabled on the only + * functional CPU. They also are executed with the PM core list of devices + * locked, so they must NOT unregister any devices. + * + * @suspend_noirq: Complete the operations of ->suspend() by carrying out any + * actions required for suspending the device that need interrupts to be + * disabled + * + * @resume_noirq: Prepare for the execution of ->resume() by carrying out any + * actions required for resuming the device that need interrupts to be + * disabled + * + * @freeze_noirq: Complete the operations of ->freeze() by carrying out any + * actions required for freezing the device that need interrupts to be + * disabled + * + * @thaw_noirq: Prepare for the execution of ->thaw() by carrying out any + * actions required for thawing the device that need interrupts to be + * disabled + * + * @poweroff_noirq: Complete the operations of ->poweroff() by carrying out any + * actions required for handling the device that need interrupts to be + * disabled + * + * @restore_noirq: Prepare for the execution of ->restore() by carrying out any + * actions required for restoring the operations of the device that need + * interrupts to be disabled + * + * All of the above callbacks return error codes, but the error codes returned + * by the resume operations, @resume_noirq(), @thaw_noirq(), and + * @restore_noirq(), do not cause the PM core to abort the resume transition + * during which they are returned. The error codes returned in that cases are + * only printed by the PM core to the system logs for debugging purposes. + * Still, as stated above, it is recommended that drivers only return error + * codes from their resume methods if the device being handled fails to resume + * and is not usable any more. + */ + +struct pm_ext_ops { + struct pm_ops base; + int (*suspend_noirq)(struct device *dev); + int (*resume_noirq)(struct device *dev); + int (*freeze_noirq)(struct device *dev); + int (*thaw_noirq)(struct device *dev); + int (*poweroff_noirq)(struct device *dev); + int (*restore_noirq)(struct device *dev); +}; + +/** + * PM_EVENT_ messages + * + * The following PM_EVENT_ messages are defined for the internal use of the PM + * core, in order to provide a mechanism allowing the high level suspend and + * hibernation code to convey the necessary information to the device PM core + * code: + * + * ON No transition. + * + * FREEZE System is going to hibernate, call ->prepare() and ->freeze() + * for all devices. + * + * SUSPEND System is going to suspend, call ->prepare() and ->suspend() + * for all devices. + * + * HIBERNATE Hibernation image has been saved, call ->prepare() and + * ->poweroff() for all devices. + * + * QUIESCE Contents of main memory are going to be restored from a (loaded) + * hibernation image, call ->prepare() and ->freeze() for all + * devices. + * + * RESUME System is resuming, call ->resume() and ->complete() for all + * devices. + * + * THAW Hibernation image has been created, call ->thaw() and + * ->complete() for all devices. + * + * RESTORE Contents of main memory have been restored from a hibernation + * image, call ->restore() and ->complete() for all devices. + * + * RECOVER Creation of a hibernation image or restoration of the main + * memory contents from a hibernation image has failed, call + * ->thaw() and ->complete() for all devices. + */ + +#define PM_EVENT_ON 0x0000 +#define PM_EVENT_FREEZE 0x0001 +#define PM_EVENT_SUSPEND 0x0002 +#define PM_EVENT_HIBERNATE 0x0004 +#define PM_EVENT_QUIESCE 0x0008 +#define PM_EVENT_RESUME 0x0010 +#define PM_EVENT_THAW 0x0020 +#define PM_EVENT_RESTORE 0x0040 +#define PM_EVENT_RECOVER 0x0080 + +#define PM_EVENT_SLEEP (PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE) + +#define PMSG_FREEZE ((struct pm_message){ .event = PM_EVENT_FREEZE, }) +#define PMSG_QUIESCE ((struct pm_message){ .event = PM_EVENT_QUIESCE, }) +#define PMSG_SUSPEND ((struct pm_message){ .event = PM_EVENT_SUSPEND, }) +#define PMSG_HIBERNATE ((struct pm_message){ .event = PM_EVENT_HIBERNATE, }) +#define PMSG_RESUME ((struct pm_message){ .event = PM_EVENT_RESUME, }) +#define PMSG_THAW ((struct pm_message){ .event = PM_EVENT_THAW, }) +#define PMSG_RESTORE ((struct pm_message){ .event = PM_EVENT_RESTORE, }) +#define PMSG_RECOVER ((struct pm_message){ .event = PM_EVENT_RECOVER, }) +#define PMSG_ON ((struct pm_message){ .event = PM_EVENT_ON, }) + +/** + * Device power management states + * + * These state labels are used internally by the PM core to indicate the current + * status of a device with respect to the PM core operations. + * + * DPM_ON Device is regarded as operational. Set this way + * initially and when ->complete() is about to be called. + * Also set when ->prepare() fails. + * + * DPM_PREPARING Device is going to be prepared for a PM transition. Set + * when ->prepare() is about to be called. + * + * DPM_RESUMING Device is going to be resumed. Set when ->resume(), + * ->thaw(), or ->restore() is about to be called. + * + * DPM_SUSPENDING Device has been prepared for a power transition. Set + * when ->prepare() has just succeeded. + * + * DPM_OFF Device is regarded as inactive. Set immediately after + * ->suspend(), ->freeze(), or ->poweroff() has succeeded. + * Also set when ->resume()_noirq, ->thaw_noirq(), or + * ->restore_noirq() is about to be called. + * + * DPM_OFF_IRQ Device is in a "deep sleep". Set immediately after + * ->suspend_noirq(), ->freeze_noirq(), or + * ->poweroff_noirq() has just succeeded. + */ + +enum dpm_state { + DPM_INVALID, + DPM_ON, + DPM_PREPARING, + DPM_RESUMING, + DPM_SUSPENDING, + DPM_OFF, + DPM_OFF_IRQ, +}; + +struct dev_pm_info { + pm_message_t power_state; + unsigned can_wakeup:1; + unsigned should_wakeup:1; + enum dpm_state status; /* Owned by the PM core */ +#ifdef CONFIG_PM_SLEEP + struct list_head entry; +#endif +}; + +/* + * The PM_EVENT_ messages are also used by drivers implementing the legacy + * suspend framework, based on the ->suspend() and ->resume() callbacks common + * for suspend and hibernation transitions, according to the rules below. + */ + +/* Necessary, because several drivers use PM_EVENT_PRETHAW */ +#define PM_EVENT_PRETHAW PM_EVENT_QUIESCE + +/* * One transition is triggered by resume(), after a suspend() call; the * message is implicit: * @@ -164,35 +444,13 @@ typedef struct pm_message { * or from system low-power states such as standby or suspend-to-RAM. */ -#define PM_EVENT_ON 0 -#define PM_EVENT_FREEZE 1 -#define PM_EVENT_SUSPEND 2 -#define PM_EVENT_HIBERNATE 4 -#define PM_EVENT_PRETHAW 8 - -#define PM_EVENT_SLEEP (PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE) - -#define PMSG_FREEZE ((struct pm_message){ .event = PM_EVENT_FREEZE, }) -#define PMSG_PRETHAW ((struct pm_message){ .event = PM_EVENT_PRETHAW, }) -#define PMSG_SUSPEND ((struct pm_message){ .event = PM_EVENT_SUSPEND, }) -#define PMSG_HIBERNATE ((struct pm_message){ .event = PM_EVENT_HIBERNATE, }) -#define PMSG_ON ((struct pm_message){ .event = PM_EVENT_ON, }) - -struct dev_pm_info { - pm_message_t power_state; - unsigned can_wakeup:1; - unsigned should_wakeup:1; - bool sleeping:1; /* Owned by the PM core */ -#ifdef CONFIG_PM_SLEEP - struct list_head entry; -#endif -}; +#ifdef CONFIG_PM_SLEEP +extern void device_pm_lock(void); +extern void device_power_up(pm_message_t state); +extern void device_resume(pm_message_t state); +extern void device_pm_unlock(void); extern int device_power_down(pm_message_t state); -extern void device_power_up(void); -extern void device_resume(void); - -#ifdef CONFIG_PM_SLEEP extern int device_suspend(pm_message_t state); extern int device_prepare_suspend(pm_message_t state); |