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Diffstat (limited to 'include/linux/vgaarb.h')
| -rw-r--r-- | include/linux/vgaarb.h | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h new file mode 100644 index 00000000000..2dfaa293ae8 --- /dev/null +++ b/include/linux/vgaarb.h @@ -0,0 +1,210 @@ +/* + * The VGA aribiter manages VGA space routing and VGA resource decode to + * allow multiple VGA devices to be used in a system in a safe way. + * + * (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org> + * (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com> + * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti@freedesktop.org> + */ + +#ifndef LINUX_VGA_H + +#include <asm/vga.h> + +/* Legacy VGA regions */ +#define VGA_RSRC_NONE 0x00 +#define VGA_RSRC_LEGACY_IO 0x01 +#define VGA_RSRC_LEGACY_MEM 0x02 +#define VGA_RSRC_LEGACY_MASK (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM) +/* Non-legacy access */ +#define VGA_RSRC_NORMAL_IO 0x04 +#define VGA_RSRC_NORMAL_MEM 0x08 + +/* Passing that instead of a pci_dev to use the system "default" + * device, that is the one used by vgacon. Archs will probably + * have to provide their own vga_default_device(); + */ +#define VGA_DEFAULT_DEVICE (NULL) + +/* For use by clients */ + +/** + * vga_set_legacy_decoding + * + * @pdev: pci device of the VGA card + * @decodes: bit mask of what legacy regions the card decodes + * + * Indicates to the arbiter if the card decodes legacy VGA IOs, + * legacy VGA Memory, both, or none. All cards default to both, + * the card driver (fbdev for example) should tell the arbiter + * if it has disabled legacy decoding, so the card can be left + * out of the arbitration process (and can be safe to take + * interrupts at any time. + */ +extern void vga_set_legacy_decoding(struct pci_dev *pdev, + unsigned int decodes); + +/** + * vga_get - acquire & locks VGA resources + * + * @pdev: pci device of the VGA card or NULL for the system default + * @rsrc: bit mask of resources to acquire and lock + * @interruptible: blocking should be interruptible by signals ? + * + * This function acquires VGA resources for the given + * card and mark those resources locked. If the resource requested + * are "normal" (and not legacy) resources, the arbiter will first check + * wether the card is doing legacy decoding for that type of resource. If + * yes, the lock is "converted" into a legacy resource lock. + * The arbiter will first look for all VGA cards that might conflict + * and disable their IOs and/or Memory access, inlcuding VGA forwarding + * on P2P bridges if necessary, so that the requested resources can + * be used. Then, the card is marked as locking these resources and + * the IO and/or Memory accesse are enabled on the card (including + * VGA forwarding on parent P2P bridges if any). + * This function will block if some conflicting card is already locking + * one of the required resources (or any resource on a different bus + * segment, since P2P bridges don't differenciate VGA memory and IO + * afaik). You can indicate wether this blocking should be interruptible + * by a signal (for userland interface) or not. + * Must not be called at interrupt time or in atomic context. + * If the card already owns the resources, the function succeeds. + * Nested calls are supported (a per-resource counter is maintained) + */ + +extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, + int interruptible); + +/** + * vga_get_interruptible + * + * Shortcut to vga_get + */ + +static inline int vga_get_interruptible(struct pci_dev *pdev, + unsigned int rsrc) +{ + return vga_get(pdev, rsrc, 1); +} + +/** + * vga_get_uninterruptible + * + * Shortcut to vga_get + */ + +static inline int vga_get_uninterruptible(struct pci_dev *pdev, + unsigned int rsrc) +{ + return vga_get(pdev, rsrc, 0); +} + +/** + * vga_tryget - try to acquire & lock legacy VGA resources + * + * @pdev: pci devivce of VGA card or NULL for system default + * @rsrc: bit mask of resources to acquire and lock + * + * This function performs the same operation as vga_get(), but + * will return an error (-EBUSY) instead of blocking if the resources + * are already locked by another card. It can be called in any context + */ + +extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc); + +/** + * vga_put - release lock on legacy VGA resources + * + * @pdev: pci device of VGA card or NULL for system default + * @rsrc: but mask of resource to release + * + * This function releases resources previously locked by vga_get() + * or vga_tryget(). The resources aren't disabled right away, so + * that a subsequence vga_get() on the same card will succeed + * immediately. Resources have a counter, so locks are only + * released if the counter reaches 0. + */ + +extern void vga_put(struct pci_dev *pdev, unsigned int rsrc); + + +/** + * vga_default_device + * + * This can be defined by the platform. The default implementation + * is rather dumb and will probably only work properly on single + * vga card setups and/or x86 platforms. + * + * If your VGA default device is not PCI, you'll have to return + * NULL here. In this case, I assume it will not conflict with + * any PCI card. If this is not true, I'll have to define two archs + * hooks for enabling/disabling the VGA default device if that is + * possible. This may be a problem with real _ISA_ VGA cards, in + * addition to a PCI one. I don't know at this point how to deal + * with that card. Can theirs IOs be disabled at all ? If not, then + * I suppose it's a matter of having the proper arch hook telling + * us about it, so we basically never allow anybody to succeed a + * vga_get()... + */ + +#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE +extern struct pci_dev *vga_default_device(void); +#endif + +/** + * vga_conflicts + * + * Architectures should define this if they have several + * independant PCI domains that can afford concurrent VGA + * decoding + */ + +#ifndef __ARCH_HAS_VGA_CONFLICT +static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) +{ + return 1; +} +#endif + +/** + * vga_client_register + * + * @pdev: pci device of the VGA client + * @cookie: client cookie to be used in callbacks + * @irq_set_state: irq state change callback + * @set_vga_decode: vga decode change callback + * + * return value: 0 on success, -1 on failure + * Register a client with the VGA arbitration logic + * + * Clients have two callback mechanisms they can use. + * irq enable/disable callback - + * If a client can't disable its GPUs VGA resources, then we + * need to be able to ask it to turn off its irqs when we + * turn off its mem and io decoding. + * set_vga_decode + * If a client can disable its GPU VGA resource, it will + * get a callback from this to set the encode/decode state + * + * Rationale: we cannot disable VGA decode resources unconditionally + * some single GPU laptops seem to require ACPI or BIOS access to the + * VGA registers to control things like backlights etc. + * Hopefully newer multi-GPU laptops do something saner, and desktops + * won't have any special ACPI for this. + * They driver will get a callback when VGA arbitration is first used + * by userspace since we some older X servers have issues. + */ +#if defined(CONFIG_VGA_ARB) +int vga_client_register(struct pci_dev *pdev, void *cookie, + void (*irq_set_state)(void *cookie, bool state), + unsigned int (*set_vga_decode)(void *cookie, bool state)); +#else +static inline int vga_client_register(struct pci_dev *pdev, void *cookie, + void (*irq_set_state)(void *cookie, bool state), + unsigned int (*set_vga_decode)(void *cookie, bool state)) +{ + return 0; +} +#endif + +#endif /* LINUX_VGA_H */ |