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vgaarb.h
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/* * 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> * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS * IN THE SOFTWARE. * */ #ifndef LINUX_VGA_H #define LINUX_VGA_H #include <video/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) struct pci_dev; /* 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 * whether 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, including 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 whether 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) */ #if defined(CONFIG_VGA_ARB) extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible); #else static inline int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) { return 0; } #endif /** * 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 */ #if defined(CONFIG_VGA_ARB) extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc); #else static inline int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { return 0; } #endif /** * 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. */ #if defined(CONFIG_VGA_ARB) extern void vga_put(struct pci_dev *pdev, unsigned int rsrc); #else #define vga_put(pdev, rsrc) #endif /** * 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 #ifdef CONFIG_VGA_ARB extern struct pci_dev *vga_default_device(void); extern void vga_set_default_device(struct pci_dev *pdev); #else static inline struct pci_dev *vga_default_device(void) { return NULL; }; static inline void vga_set_default_device(struct pci_dev *pdev) { }; #endif #endif /** * vga_conflicts * * Architectures should define this if they have several * independent 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 */
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