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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 

 * (C) Copyright 2007 Paulo R. Zanoni 

 * (C) Copyright 2007, 2009 Tiago Vignatti 

 *

 * 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 

/* 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.

 */

#if defined(CONFIG_VGA_ARB)

extern void vga_set_legacy_decoding(struct pci_dev *pdev,

				    unsigned int decodes);

#else

static inline void vga_set_legacy_decoding(struct pci_dev *pdev,

					   unsigned int decodes) { };

#endif

/**

 *     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()...

 */

#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

/**

 *     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 */