FreeBSD/Linux Kernel Cross Reference
sys/compat/linuxkpi/common/include/linux/vgaarb.h

     /*
      * 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 _LINUXKPI_LINUX_VGA_H_
    #define _LINUXKPI_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.
     */
    #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 /* _LINUXKPI_LINUX_VGA_H_ */

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