/**************************************************************************
   *
   * Copyright (c) 2006-2009 Vmware, Inc., Palo Alto, CA., USA
   * All Rights Reserved.
   *
   * 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, sub license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
   * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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.
   *
   **************************************************************************/
  /*
   * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
   */
  #ifndef _TTM_BO_DRIVER_H_
  #define _TTM_BO_DRIVER_H_
  
  #include "ttm/ttm_bo_api.h"
  #include "ttm/ttm_memory.h"

  #include "ttm/ttm_module.h"

  #include "drm_mm.h"

  #include "drm_global.h"

  #include "linux/workqueue.h"
  #include "linux/fs.h"
  #include "linux/spinlock.h"
  
  struct ttm_backend;
  
  struct ttm_backend_func {
  	/**

  	 * struct ttm_backend_func member bind
  	 *

  	 * @ttm: Pointer to a struct ttm_tt.

  	 * @bo_mem: Pointer to a struct ttm_mem_reg describing the
  	 * memory type and location for binding.
  	 *
  	 * Bind the backend pages into the aperture in the location
  	 * indicated by @bo_mem. This function should be able to handle

  	 * differences between aperture and system page sizes.

  	 */

  	int (*bind) (struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem);

  
  	/**
  	 * struct ttm_backend_func member unbind
  	 *

  	 * @ttm: Pointer to a struct ttm_tt.

  	 *
  	 * Unbind previously bound backend pages. This function should be

  	 * able to handle differences between aperture and system page sizes.

  	 */

  	int (*unbind) (struct ttm_tt *ttm);

  
  	/**
  	 * struct ttm_backend_func member destroy
  	 *

  	 * @ttm: Pointer to a struct ttm_tt.

  	 *

  	 * Destroy the backend. This will be call back from ttm_tt_destroy so
  	 * don't call ttm_tt_destroy from the callback or infinite loop.

  	 */

  	void (*destroy) (struct ttm_tt *ttm);

  };

  #define TTM_PAGE_FLAG_WRITE           (1 << 3)
  #define TTM_PAGE_FLAG_SWAPPED         (1 << 4)

  #define TTM_PAGE_FLAG_PERSISTENT_SWAP (1 << 5)

  #define TTM_PAGE_FLAG_ZERO_ALLOC      (1 << 6)

  #define TTM_PAGE_FLAG_DMA32           (1 << 7)

  
  enum ttm_caching_state {
  	tt_uncached,
  	tt_wc,
  	tt_cached
  };
  
  /**
   * struct ttm_tt
   *

   * @bdev: Pointer to a struct ttm_bo_device.
   * @func: Pointer to a struct ttm_backend_func that describes
   * the backend methods.

   * @dummy_read_page: Page to map where the ttm_tt page array contains a NULL
   * pointer.
   * @pages: Array of pages backing the data.

   * @num_pages: Number of pages in the page array.
   * @bdev: Pointer to the current struct ttm_bo_device.
   * @be: Pointer to the ttm backend.

   * @swap_storage: Pointer to shmem struct file for swap storage.
   * @caching_state: The current caching state of the pages.
   * @state: The current binding state of the pages.
   *
   * This is a structure holding the pages, caching- and aperture binding
   * status for a buffer object that isn't backed by fixed (VRAM / AGP)
   * memory.
   */
  
  struct ttm_tt {

  	struct ttm_bo_device *bdev;
  	struct ttm_backend_func *func;

  	struct page *dummy_read_page;
  	struct page **pages;

  	uint32_t page_flags;
  	unsigned long num_pages;

  	struct ttm_bo_global *glob;

  	struct ttm_backend *be;

  	struct file *swap_storage;
  	enum ttm_caching_state caching_state;
  	enum {
  		tt_bound,
  		tt_unbound,
  		tt_unpopulated,
  	} state;

  };
  
  /**
   * struct ttm_dma_tt
   *
   * @ttm: Base ttm_tt struct.
   * @dma_address: The DMA (bus) addresses of the pages
   * @pages_list: used by some page allocation backend
   *
   * This is a structure holding the pages, caching- and aperture binding
   * status for a buffer object that isn't backed by fixed (VRAM / AGP)
   * memory.
   */
  struct ttm_dma_tt {
  	struct ttm_tt ttm;

  	dma_addr_t *dma_address;

  	struct list_head pages_list;

  };
  
  #define TTM_MEMTYPE_FLAG_FIXED         (1 << 0)	/* Fixed (on-card) PCI memory */
  #define TTM_MEMTYPE_FLAG_MAPPABLE      (1 << 1)	/* Memory mappable */

  #define TTM_MEMTYPE_FLAG_CMA           (1 << 3)	/* Can't map aperture */

  struct ttm_mem_type_manager;
  
  struct ttm_mem_type_manager_func {

  	/**
  	 * struct ttm_mem_type_manager member init
  	 *
  	 * @man: Pointer to a memory type manager.
  	 * @p_size: Implementation dependent, but typically the size of the
  	 * range to be managed in pages.
  	 *
  	 * Called to initialize a private range manager. The function is
  	 * expected to initialize the man::priv member.
  	 * Returns 0 on success, negative error code on failure.
  	 */

  	int  (*init)(struct ttm_mem_type_manager *man, unsigned long p_size);

  
  	/**
  	 * struct ttm_mem_type_manager member takedown
  	 *
  	 * @man: Pointer to a memory type manager.
  	 *
  	 * Called to undo the setup done in init. All allocated resources
  	 * should be freed.
  	 */

  	int  (*takedown)(struct ttm_mem_type_manager *man);

  
  	/**
  	 * struct ttm_mem_type_manager member get_node
  	 *
  	 * @man: Pointer to a memory type manager.
  	 * @bo: Pointer to the buffer object we're allocating space for.
  	 * @placement: Placement details.
  	 * @mem: Pointer to a struct ttm_mem_reg to be filled in.
  	 *
  	 * This function should allocate space in the memory type managed
  	 * by @man. Placement details if
  	 * applicable are given by @placement. If successful,
  	 * @mem::mm_node should be set to a non-null value, and
  	 * @mem::start should be set to a value identifying the beginning
  	 * of the range allocated, and the function should return zero.

  	 * If the memory region accommodate the buffer object, @mem::mm_node

  	 * should be set to NULL, and the function should return 0.

  	 * If a system error occurred, preventing the request to be fulfilled,

  	 * the function should return a negative error code.
  	 *
  	 * Note that @mem::mm_node will only be dereferenced by
  	 * struct ttm_mem_type_manager functions and optionally by the driver,
  	 * which has knowledge of the underlying type.
  	 *
  	 * This function may not be called from within atomic context, so
  	 * an implementation can and must use either a mutex or a spinlock to
  	 * protect any data structures managing the space.
  	 */

  	int  (*get_node)(struct ttm_mem_type_manager *man,
  			 struct ttm_buffer_object *bo,
  			 struct ttm_placement *placement,
  			 struct ttm_mem_reg *mem);

  
  	/**
  	 * struct ttm_mem_type_manager member put_node
  	 *
  	 * @man: Pointer to a memory type manager.
  	 * @mem: Pointer to a struct ttm_mem_reg to be filled in.
  	 *
  	 * This function frees memory type resources previously allocated
  	 * and that are identified by @mem::mm_node and @mem::start. May not
  	 * be called from within atomic context.
  	 */

  	void (*put_node)(struct ttm_mem_type_manager *man,
  			 struct ttm_mem_reg *mem);

  
  	/**
  	 * struct ttm_mem_type_manager member debug
  	 *
  	 * @man: Pointer to a memory type manager.
  	 * @prefix: Prefix to be used in printout to identify the caller.
  	 *
  	 * This function is called to print out the state of the memory
  	 * type manager to aid debugging of out-of-memory conditions.
  	 * It may not be called from within atomic context.
  	 */

  	void (*debug)(struct ttm_mem_type_manager *man, const char *prefix);
  };

  /**
   * struct ttm_mem_type_manager
   *
   * @has_type: The memory type has been initialized.
   * @use_type: The memory type is enabled.
   * @flags: TTM_MEMTYPE_XX flags identifying the traits of the memory
   * managed by this memory type.
   * @gpu_offset: If used, the GPU offset of the first managed page of
   * fixed memory or the first managed location in an aperture.
   * @size: Size of the managed region.
   * @available_caching: A mask of available caching types, TTM_PL_FLAG_XX,
   * as defined in ttm_placement_common.h
   * @default_caching: The default caching policy used for a buffer object
   * placed in this memory type if the user doesn't provide one.
   * @func: structure pointer implementing the range manager. See above
   * @priv: Driver private closure for @func.
   * @io_reserve_mutex: Mutex optionally protecting shared io_reserve structures
   * @use_io_reserve_lru: Use an lru list to try to unreserve io_mem_regions
   * reserved by the TTM vm system.
   * @io_reserve_lru: Optional lru list for unreserving io mem regions.
   * @io_reserve_fastpath: Only use bdev::driver::io_mem_reserve to obtain
   * static information. bdev::driver::io_mem_free is never used.
   * @lru: The lru list for this memory type.
   *
   * This structure is used to identify and manage memory types for a device.
   * It's set up by the ttm_bo_driver::init_mem_type method.
   */

  struct ttm_mem_type_manager {

  	struct ttm_bo_device *bdev;

  
  	/*
  	 * No protection. Constant from start.
  	 */
  
  	bool has_type;
  	bool use_type;
  	uint32_t flags;
  	unsigned long gpu_offset;

  	uint64_t size;
  	uint32_t available_caching;
  	uint32_t default_caching;

  	const struct ttm_mem_type_manager_func *func;
  	void *priv;

  	struct mutex io_reserve_mutex;
  	bool use_io_reserve_lru;
  	bool io_reserve_fastpath;
  
  	/*
  	 * Protected by @io_reserve_mutex:
  	 */
  
  	struct list_head io_reserve_lru;

  
  	/*

  	 * Protected by the global->lru_lock.

  	 */

  	struct list_head lru;
  };
  
  /**
   * struct ttm_bo_driver
   *

   * @create_ttm_backend_entry: Callback to create a struct ttm_backend.
   * @invalidate_caches: Callback to invalidate read caches when a buffer object
   * has been evicted.
   * @init_mem_type: Callback to initialize a struct ttm_mem_type_manager
   * structure.
   * @evict_flags: Callback to obtain placement flags when a buffer is evicted.
   * @move: Callback for a driver to hook in accelerated functions to
   * move a buffer.
   * If set to NULL, a potentially slow memcpy() move is used.
   * @sync_obj_signaled: See ttm_fence_api.h
   * @sync_obj_wait: See ttm_fence_api.h
   * @sync_obj_flush: See ttm_fence_api.h
   * @sync_obj_unref: See ttm_fence_api.h
   * @sync_obj_ref: See ttm_fence_api.h
   */
  
  struct ttm_bo_driver {

  	/**

  	 * ttm_tt_create

  	 *

  	 * @bdev: pointer to a struct ttm_bo_device:
  	 * @size: Size of the data needed backing.
  	 * @page_flags: Page flags as identified by TTM_PAGE_FLAG_XX flags.
  	 * @dummy_read_page: See struct ttm_bo_device.

  	 *

  	 * Create a struct ttm_tt to back data with system memory pages.
  	 * No pages are actually allocated.
  	 * Returns:
  	 * NULL: Out of memory.

  	 */

  	struct ttm_tt *(*ttm_tt_create)(struct ttm_bo_device *bdev,
  					unsigned long size,
  					uint32_t page_flags,
  					struct page *dummy_read_page);

  
  	/**

  	 * ttm_tt_populate
  	 *
  	 * @ttm: The struct ttm_tt to contain the backing pages.
  	 *
  	 * Allocate all backing pages
  	 * Returns:
  	 * -ENOMEM: Out of memory.
  	 */
  	int (*ttm_tt_populate)(struct ttm_tt *ttm);
  
  	/**
  	 * ttm_tt_unpopulate
  	 *
  	 * @ttm: The struct ttm_tt to contain the backing pages.
  	 *
  	 * Free all backing page
  	 */
  	void (*ttm_tt_unpopulate)(struct ttm_tt *ttm);
  
  	/**

  	 * struct ttm_bo_driver member invalidate_caches
  	 *
  	 * @bdev: the buffer object device.
  	 * @flags: new placement of the rebound buffer object.
  	 *
  	 * A previosly evicted buffer has been rebound in a
  	 * potentially new location. Tell the driver that it might
  	 * consider invalidating read (texture) caches on the next command
  	 * submission as a consequence.
  	 */
  
  	int (*invalidate_caches) (struct ttm_bo_device *bdev, uint32_t flags);
  	int (*init_mem_type) (struct ttm_bo_device *bdev, uint32_t type,
  			      struct ttm_mem_type_manager *man);
  	/**
  	 * struct ttm_bo_driver member evict_flags:
  	 *
  	 * @bo: the buffer object to be evicted
  	 *
  	 * Return the bo flags for a buffer which is not mapped to the hardware.
  	 * These will be placed in proposed_flags so that when the move is
  	 * finished, they'll end up in bo->mem.flags
  	 */

  	 void(*evict_flags) (struct ttm_buffer_object *bo,
  				struct ttm_placement *placement);

  	/**
  	 * struct ttm_bo_driver member move:
  	 *
  	 * @bo: the buffer to move
  	 * @evict: whether this motion is evicting the buffer from
  	 * the graphics address space
  	 * @interruptible: Use interruptible sleeps if possible when sleeping.
  	 * @no_wait: whether this should give up and return -EBUSY
  	 * if this move would require sleeping
  	 * @new_mem: the new memory region receiving the buffer
  	 *
  	 * Move a buffer between two memory regions.
  	 */
  	int (*move) (struct ttm_buffer_object *bo,
  		     bool evict, bool interruptible,

  		     bool no_wait_reserve, bool no_wait_gpu,
  		     struct ttm_mem_reg *new_mem);

  
  	/**
  	 * struct ttm_bo_driver_member verify_access
  	 *
  	 * @bo: Pointer to a buffer object.
  	 * @filp: Pointer to a struct file trying to access the object.
  	 *
  	 * Called from the map / write / read methods to verify that the
  	 * caller is permitted to access the buffer object.
  	 * This member may be set to NULL, which will refuse this kind of
  	 * access for all buffer objects.
  	 * This function should return 0 if access is granted, -EPERM otherwise.
  	 */
  	int (*verify_access) (struct ttm_buffer_object *bo,
  			      struct file *filp);
  
  	/**
  	 * In case a driver writer dislikes the TTM fence objects,
  	 * the driver writer can replace those with sync objects of
  	 * his / her own. If it turns out that no driver writer is
  	 * using these. I suggest we remove these hooks and plug in
  	 * fences directly. The bo driver needs the following functionality:
  	 * See the corresponding functions in the fence object API
  	 * documentation.
  	 */
  
  	bool (*sync_obj_signaled) (void *sync_obj, void *sync_arg);
  	int (*sync_obj_wait) (void *sync_obj, void *sync_arg,
  			      bool lazy, bool interruptible);
  	int (*sync_obj_flush) (void *sync_obj, void *sync_arg);
  	void (*sync_obj_unref) (void **sync_obj);
  	void *(*sync_obj_ref) (void *sync_obj);

  
  	/* hook to notify driver about a driver move so it
  	 * can do tiling things */
  	void (*move_notify)(struct ttm_buffer_object *bo,
  			    struct ttm_mem_reg *new_mem);
  	/* notify the driver we are taking a fault on this BO
  	 * and have reserved it */

  	int (*fault_reserve_notify)(struct ttm_buffer_object *bo);

  
  	/**
  	 * notify the driver that we're about to swap out this bo
  	 */
  	void (*swap_notify) (struct ttm_buffer_object *bo);

  
  	/**
  	 * Driver callback on when mapping io memory (for bo_move_memcpy
  	 * for instance). TTM will take care to call io_mem_free whenever
  	 * the mapping is not use anymore. io_mem_reserve & io_mem_free
  	 * are balanced.
  	 */
  	int (*io_mem_reserve)(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem);
  	void (*io_mem_free)(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem);

  };

  /**
   * struct ttm_bo_global_ref - Argument to initialize a struct ttm_bo_global.
   */
  
  struct ttm_bo_global_ref {

  	struct drm_global_reference ref;

  	struct ttm_mem_global *mem_glob;
  };

  /**

   * struct ttm_bo_global - Buffer object driver global data.

   *
   * @mem_glob: Pointer to a struct ttm_mem_global object for accounting.

   * @dummy_read_page: Pointer to a dummy page used for mapping requests
   * of unpopulated pages.

   * @shrink: A shrink callback object used for buffer object swap.

   * @device_list_mutex: Mutex protecting the device list.
   * This mutex is held while traversing the device list for pm options.
   * @lru_lock: Spinlock protecting the bo subsystem lru lists.
   * @device_list: List of buffer object devices.
   * @swap_lru: Lru list of buffer objects used for swapping.
   */
  
  struct ttm_bo_global {
  
  	/**
  	 * Constant after init.
  	 */
  
  	struct kobject kobj;
  	struct ttm_mem_global *mem_glob;
  	struct page *dummy_read_page;
  	struct ttm_mem_shrink shrink;

  	struct mutex device_list_mutex;
  	spinlock_t lru_lock;
  
  	/**
  	 * Protected by device_list_mutex.
  	 */
  	struct list_head device_list;
  
  	/**
  	 * Protected by the lru_lock.
  	 */
  	struct list_head swap_lru;
  
  	/**
  	 * Internal protection.
  	 */
  	atomic_t bo_count;
  };
  
  
  #define TTM_NUM_MEM_TYPES 8
  
  #define TTM_BO_PRIV_FLAG_MOVING  0	/* Buffer object is moving and needs
  					   idling before CPU mapping */
  #define TTM_BO_PRIV_FLAG_MAX 1
  /**
   * struct ttm_bo_device - Buffer object driver device-specific data.
   *
   * @driver: Pointer to a struct ttm_bo_driver struct setup by the driver.

   * @man: An array of mem_type_managers.

   * @fence_lock: Protects the synchronizing members on *all* bos belonging
   * to this device.

   * @addr_space_mm: Range manager for the device address space.
   * lru_lock: Spinlock that protects the buffer+device lru lists and
   * ddestroy lists.

   * @val_seq: Current validation sequence.

   * @nice_mode: Try nicely to wait for buffer idle when cleaning a manager.
   * If a GPU lockup has been detected, this is forced to 0.
   * @dev_mapping: A pointer to the struct address_space representing the
   * device address space.
   * @wq: Work queue structure for the delayed delete workqueue.
   *
   */
  
  struct ttm_bo_device {
  
  	/*
  	 * Constant after bo device init / atomic.
  	 */

  	struct list_head device_list;
  	struct ttm_bo_global *glob;

  	struct ttm_bo_driver *driver;

  	rwlock_t vm_lock;

  	struct ttm_mem_type_manager man[TTM_NUM_MEM_TYPES];

  	spinlock_t fence_lock;

  	/*
  	 * Protected by the vm lock.
  	 */

  	struct rb_root addr_space_rb;
  	struct drm_mm addr_space_mm;
  
  	/*

  	 * Protected by the global:lru lock.

  	 */
  	struct list_head ddestroy;

  	uint32_t val_seq;

  
  	/*
  	 * Protected by load / firstopen / lastclose /unload sync.
  	 */
  
  	bool nice_mode;
  	struct address_space *dev_mapping;
  
  	/*
  	 * Internal protection.
  	 */
  
  	struct delayed_work wq;

  
  	bool need_dma32;

  };
  
  /**
   * ttm_flag_masked
   *
   * @old: Pointer to the result and original value.
   * @new: New value of bits.
   * @mask: Mask of bits to change.
   *
   * Convenience function to change a number of bits identified by a mask.
   */
  
  static inline uint32_t
  ttm_flag_masked(uint32_t *old, uint32_t new, uint32_t mask)
  {
  	*old ^= (*old ^ new) & mask;
  	return *old;
  }
  
  /**

   * ttm_tt_init

   *

   * @ttm: The struct ttm_tt.

   * @bdev: pointer to a struct ttm_bo_device:
   * @size: Size of the data needed backing.
   * @page_flags: Page flags as identified by TTM_PAGE_FLAG_XX flags.
   * @dummy_read_page: See struct ttm_bo_device.
   *
   * Create a struct ttm_tt to back data with system memory pages.
   * No pages are actually allocated.
   * Returns:
   * NULL: Out of memory.
   */

  extern int ttm_tt_init(struct ttm_tt *ttm, struct ttm_bo_device *bdev,
  			unsigned long size, uint32_t page_flags,
  			struct page *dummy_read_page);

  extern int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_bo_device *bdev,
  			   unsigned long size, uint32_t page_flags,
  			   struct page *dummy_read_page);
  
  /**
   * ttm_tt_fini
   *
   * @ttm: the ttm_tt structure.
   *
   * Free memory of ttm_tt structure
   */
  extern void ttm_tt_fini(struct ttm_tt *ttm);
  extern void ttm_dma_tt_fini(struct ttm_dma_tt *ttm_dma);

  
  /**

   * ttm_ttm_bind:
   *
   * @ttm: The struct ttm_tt containing backing pages.
   * @bo_mem: The struct ttm_mem_reg identifying the binding location.
   *
   * Bind the pages of @ttm to an aperture location identified by @bo_mem
   */
  extern int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem);
  
  /**
   * ttm_ttm_destroy:
   *
   * @ttm: The struct ttm_tt.
   *

   * Unbind, unpopulate and destroy common struct ttm_tt.

   */
  extern void ttm_tt_destroy(struct ttm_tt *ttm);
  
  /**
   * ttm_ttm_unbind:
   *
   * @ttm: The struct ttm_tt.
   *
   * Unbind a struct ttm_tt.
   */
  extern void ttm_tt_unbind(struct ttm_tt *ttm);
  
  /**

   * ttm_tt_swapin:

   *
   * @ttm: The struct ttm_tt.

   *

   * Swap in a previously swap out ttm_tt.

   */

  extern int ttm_tt_swapin(struct ttm_tt *ttm);

  
  /**
   * ttm_tt_cache_flush:
   *
   * @pages: An array of pointers to struct page:s to flush.
   * @num_pages: Number of pages to flush.
   *
   * Flush the data of the indicated pages from the cpu caches.
   * This is used when changing caching attributes of the pages from
   * cache-coherent.
   */
  extern void ttm_tt_cache_flush(struct page *pages[], unsigned long num_pages);
  
  /**
   * ttm_tt_set_placement_caching:
   *
   * @ttm A struct ttm_tt the backing pages of which will change caching policy.
   * @placement: Flag indicating the desired caching policy.
   *
   * This function will change caching policy of any default kernel mappings of
   * the pages backing @ttm. If changing from cached to uncached or
   * write-combined,
   * all CPU caches will first be flushed to make sure the data of the pages
   * hit RAM. This function may be very costly as it involves global TLB
   * and cache flushes and potential page splitting / combining.
   */
  extern int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement);
  extern int ttm_tt_swapout(struct ttm_tt *ttm,

  			  struct file *persistent_swap_storage);

  
  /*
   * ttm_bo.c
   */
  
  /**
   * ttm_mem_reg_is_pci
   *
   * @bdev: Pointer to a struct ttm_bo_device.
   * @mem: A valid struct ttm_mem_reg.
   *
   * Returns true if the memory described by @mem is PCI memory,
   * false otherwise.
   */
  extern bool ttm_mem_reg_is_pci(struct ttm_bo_device *bdev,
  				   struct ttm_mem_reg *mem);
  
  /**
   * ttm_bo_mem_space
   *
   * @bo: Pointer to a struct ttm_buffer_object. the data of which
   * we want to allocate space for.
   * @proposed_placement: Proposed new placement for the buffer object.
   * @mem: A struct ttm_mem_reg.
   * @interruptible: Sleep interruptible when sliping.

   * @no_wait_reserve: Return immediately if other buffers are busy.
   * @no_wait_gpu: Return immediately if the GPU is busy.

   *
   * Allocate memory space for the buffer object pointed to by @bo, using
   * the placement flags in @mem, potentially evicting other idle buffer objects.
   * This function may sleep while waiting for space to become available.
   * Returns:
   * -EBUSY: No space available (only if no_wait == 1).
   * -ENOMEM: Could not allocate memory for the buffer object, either due to
   * fragmentation or concurrent allocators.

   * -ERESTARTSYS: An interruptible sleep was interrupted by a signal.

   */
  extern int ttm_bo_mem_space(struct ttm_buffer_object *bo,

  				struct ttm_placement *placement,
  				struct ttm_mem_reg *mem,

  				bool interruptible,
  				bool no_wait_reserve, bool no_wait_gpu);

  
  extern void ttm_bo_mem_put(struct ttm_buffer_object *bo,
  			   struct ttm_mem_reg *mem);

  extern void ttm_bo_mem_put_locked(struct ttm_buffer_object *bo,
  				  struct ttm_mem_reg *mem);

  /**
   * ttm_bo_wait_for_cpu
   *
   * @bo: Pointer to a struct ttm_buffer_object.
   * @no_wait: Don't sleep while waiting.
   *
   * Wait until a buffer object is no longer sync'ed for CPU access.
   * Returns:
   * -EBUSY: Buffer object was sync'ed for CPU access. (only if no_wait == 1).

   * -ERESTARTSYS: An interruptible sleep was interrupted by a signal.

   */
  
  extern int ttm_bo_wait_cpu(struct ttm_buffer_object *bo, bool no_wait);

  extern void ttm_bo_global_release(struct drm_global_reference *ref);
  extern int ttm_bo_global_init(struct drm_global_reference *ref);

  extern int ttm_bo_device_release(struct ttm_bo_device *bdev);
  
  /**
   * ttm_bo_device_init
   *
   * @bdev: A pointer to a struct ttm_bo_device to initialize.

   * @glob: A pointer to an initialized struct ttm_bo_global.

   * @driver: A pointer to a struct ttm_bo_driver set up by the caller.
   * @file_page_offset: Offset into the device address space that is available
   * for buffer data. This ensures compatibility with other users of the
   * address space.
   *
   * Initializes a struct ttm_bo_device:
   * Returns:
   * !0: Failure.
   */
  extern int ttm_bo_device_init(struct ttm_bo_device *bdev,

  			      struct ttm_bo_global *glob,

  			      struct ttm_bo_driver *driver,

  			      uint64_t file_page_offset, bool need_dma32);

  
  /**

   * ttm_bo_unmap_virtual
   *
   * @bo: tear down the virtual mappings for this BO
   */
  extern void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo);

  
  /**

   * ttm_bo_unmap_virtual
   *
   * @bo: tear down the virtual mappings for this BO
   *
   * The caller must take ttm_mem_io_lock before calling this function.
   */
  extern void ttm_bo_unmap_virtual_locked(struct ttm_buffer_object *bo);
  
  extern int ttm_mem_io_reserve_vm(struct ttm_buffer_object *bo);
  extern void ttm_mem_io_free_vm(struct ttm_buffer_object *bo);
  extern int ttm_mem_io_lock(struct ttm_mem_type_manager *man,
  			   bool interruptible);
  extern void ttm_mem_io_unlock(struct ttm_mem_type_manager *man);
  
  
  /**

   * ttm_bo_reserve:
   *
   * @bo: A pointer to a struct ttm_buffer_object.
   * @interruptible: Sleep interruptible if waiting.
   * @no_wait: Don't sleep while trying to reserve, rather return -EBUSY.
   * @use_sequence: If @bo is already reserved, Only sleep waiting for
   * it to become unreserved if @sequence < (@bo)->sequence.
   *
   * Locks a buffer object for validation. (Or prevents other processes from
   * locking it for validation) and removes it from lru lists, while taking
   * a number of measures to prevent deadlocks.
   *
   * Deadlocks may occur when two processes try to reserve multiple buffers in
   * different order, either by will or as a result of a buffer being evicted
   * to make room for a buffer already reserved. (Buffers are reserved before
   * they are evicted). The following algorithm prevents such deadlocks from

   * occurring:

   * 1) Buffers are reserved with the lru spinlock held. Upon successful
   * reservation they are removed from the lru list. This stops a reserved buffer
   * from being evicted. However the lru spinlock is released between the time
   * a buffer is selected for eviction and the time it is reserved.
   * Therefore a check is made when a buffer is reserved for eviction, that it
   * is still the first buffer in the lru list, before it is removed from the
   * list. @check_lru == 1 forces this check. If it fails, the function returns
   * -EINVAL, and the caller should then choose a new buffer to evict and repeat
   * the procedure.
   * 2) Processes attempting to reserve multiple buffers other than for eviction,
   * (typically execbuf), should first obtain a unique 32-bit
   * validation sequence number,
   * and call this function with @use_sequence == 1 and @sequence == the unique
   * sequence number. If upon call of this function, the buffer object is already
   * reserved, the validation sequence is checked against the validation
   * sequence of the process currently reserving the buffer,
   * and if the current validation sequence is greater than that of the process
   * holding the reservation, the function returns -EAGAIN. Otherwise it sleeps
   * waiting for the buffer to become unreserved, after which it retries
   * reserving.
   * The caller should, when receiving an -EAGAIN error
   * release all its buffer reservations, wait for @bo to become unreserved, and
   * then rerun the validation with the same validation sequence. This procedure
   * will always guarantee that the process with the lowest validation sequence
   * will eventually succeed, preventing both deadlocks and starvation.
   *
   * Returns:
   * -EAGAIN: The reservation may cause a deadlock.
   * Release all buffer reservations, wait for @bo to become unreserved and
   * try again. (only if use_sequence == 1).

   * -ERESTARTSYS: A wait for the buffer to become unreserved was interrupted by

   * a signal. Release all buffer reservations and return to user-space.

   * -EBUSY: The function needed to sleep, but @no_wait was true
   * -EDEADLK: Bo already reserved using @sequence. This error code will only
   * be returned if @use_sequence is set to true.

   */
  extern int ttm_bo_reserve(struct ttm_buffer_object *bo,
  			  bool interruptible,
  			  bool no_wait, bool use_sequence, uint32_t sequence);

  
  /**
   * ttm_bo_reserve_locked:
   *

   * @bo: A pointer to a struct ttm_buffer_object.
   * @interruptible: Sleep interruptible if waiting.
   * @no_wait: Don't sleep while trying to reserve, rather return -EBUSY.
   * @use_sequence: If @bo is already reserved, Only sleep waiting for
   * it to become unreserved if @sequence < (@bo)->sequence.
   *
   * Must be called with struct ttm_bo_global::lru_lock held,
   * and will not remove reserved buffers from the lru lists.

   * The function may release the LRU spinlock if it needs to sleep.

   * Otherwise identical to ttm_bo_reserve.
   *
   * Returns:
   * -EAGAIN: The reservation may cause a deadlock.
   * Release all buffer reservations, wait for @bo to become unreserved and
   * try again. (only if use_sequence == 1).
   * -ERESTARTSYS: A wait for the buffer to become unreserved was interrupted by
   * a signal. Release all buffer reservations and return to user-space.
   * -EBUSY: The function needed to sleep, but @no_wait was true
   * -EDEADLK: Bo already reserved using @sequence. This error code will only
   * be returned if @use_sequence is set to true.

   */

  extern int ttm_bo_reserve_locked(struct ttm_buffer_object *bo,
  				 bool interruptible,
  				 bool no_wait, bool use_sequence,
  				 uint32_t sequence);

  /**
   * ttm_bo_unreserve
   *
   * @bo: A pointer to a struct ttm_buffer_object.
   *
   * Unreserve a previous reservation of @bo.
   */
  extern void ttm_bo_unreserve(struct ttm_buffer_object *bo);
  
  /**

   * ttm_bo_unreserve_locked
   *
   * @bo: A pointer to a struct ttm_buffer_object.
   *
   * Unreserve a previous reservation of @bo.
   * Needs to be called with struct ttm_bo_global::lru_lock held.
   */
  extern void ttm_bo_unreserve_locked(struct ttm_buffer_object *bo);
  
  /**

   * ttm_bo_wait_unreserved
   *
   * @bo: A pointer to a struct ttm_buffer_object.
   *
   * Wait for a struct ttm_buffer_object to become unreserved.
   * This is typically used in the execbuf code to relax cpu-usage when
   * a potential deadlock condition backoff.
   */
  extern int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo,
  				  bool interruptible);

  /*
   * ttm_bo_util.c
   */
  
  /**
   * ttm_bo_move_ttm
   *
   * @bo: A pointer to a struct ttm_buffer_object.
   * @evict: 1: This is an eviction. Don't try to pipeline.

   * @no_wait_reserve: Return immediately if other buffers are busy.
   * @no_wait_gpu: Return immediately if the GPU is busy.

   * @new_mem: struct ttm_mem_reg indicating where to move.
   *
   * Optimized move function for a buffer object with both old and
   * new placement backed by a TTM. The function will, if successful,
   * free any old aperture space, and set (@new_mem)->mm_node to NULL,
   * and update the (@bo)->mem placement flags. If unsuccessful, the old
   * data remains untouched, and it's up to the caller to free the
   * memory space indicated by @new_mem.
   * Returns:
   * !0: Failure.
   */
  
  extern int ttm_bo_move_ttm(struct ttm_buffer_object *bo,

  			   bool evict, bool no_wait_reserve,
  			   bool no_wait_gpu, struct ttm_mem_reg *new_mem);

  
  /**
   * ttm_bo_move_memcpy
   *
   * @bo: A pointer to a struct ttm_buffer_object.
   * @evict: 1: This is an eviction. Don't try to pipeline.

   * @no_wait_reserve: Return immediately if other buffers are busy.
   * @no_wait_gpu: Return immediately if the GPU is busy.

   * @new_mem: struct ttm_mem_reg indicating where to move.
   *
   * Fallback move function for a mappable buffer object in mappable memory.
   * The function will, if successful,
   * free any old aperture space, and set (@new_mem)->mm_node to NULL,
   * and update the (@bo)->mem placement flags. If unsuccessful, the old
   * data remains untouched, and it's up to the caller to free the
   * memory space indicated by @new_mem.
   * Returns:
   * !0: Failure.
   */
  
  extern int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,

  			      bool evict, bool no_wait_reserve,
  			      bool no_wait_gpu, struct ttm_mem_reg *new_mem);

  
  /**
   * ttm_bo_free_old_node
   *
   * @bo: A pointer to a struct ttm_buffer_object.
   *
   * Utility function to free an old placement after a successful move.
   */
  extern void ttm_bo_free_old_node(struct ttm_buffer_object *bo);
  
  /**
   * ttm_bo_move_accel_cleanup.
   *
   * @bo: A pointer to a struct ttm_buffer_object.
   * @sync_obj: A sync object that signals when moving is complete.
   * @sync_obj_arg: An argument to pass to the sync object idle / wait
   * functions.
   * @evict: This is an evict move. Don't return until the buffer is idle.

   * @no_wait_reserve: Return immediately if other buffers are busy.
   * @no_wait_gpu: Return immediately if the GPU is busy.

   * @new_mem: struct ttm_mem_reg indicating where to move.
   *
   * Accelerated move function to be called when an accelerated move
   * has been scheduled. The function will create a new temporary buffer object
   * representing the old placement, and put the sync object on both buffer
   * objects. After that the newly created buffer object is unref'd to be
   * destroyed when the move is complete. This will help pipeline
   * buffer moves.
   */
  
  extern int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
  				     void *sync_obj,
  				     void *sync_obj_arg,

  				     bool evict, bool no_wait_reserve,
  				     bool no_wait_gpu,

  				     struct ttm_mem_reg *new_mem);
  /**
   * ttm_io_prot
   *
   * @c_state: Caching state.
   * @tmp: Page protection flag for a normal, cached mapping.
   *
   * Utility function that returns the pgprot_t that should be used for
   * setting up a PTE with the caching model indicated by @c_state.
   */

  extern pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp);

  extern const struct ttm_mem_type_manager_func ttm_bo_manager_func;

  #if (defined(CONFIG_AGP) || (defined(CONFIG_AGP_MODULE) && defined(MODULE)))
  #define TTM_HAS_AGP
  #include <linux/agp_backend.h>
  
  /**

   * ttm_agp_tt_create

   *
   * @bdev: Pointer to a struct ttm_bo_device.
   * @bridge: The agp bridge this device is sitting on.

   * @size: Size of the data needed backing.
   * @page_flags: Page flags as identified by TTM_PAGE_FLAG_XX flags.
   * @dummy_read_page: See struct ttm_bo_device.
   *

   *
   * Create a TTM backend that uses the indicated AGP bridge as an aperture
   * for TT memory. This function uses the linux agpgart interface to
   * bind and unbind memory backing a ttm_tt.
   */

  extern struct ttm_tt *ttm_agp_tt_create(struct ttm_bo_device *bdev,
  					struct agp_bridge_data *bridge,
  					unsigned long size, uint32_t page_flags,
  					struct page *dummy_read_page);

  int ttm_agp_tt_populate(struct ttm_tt *ttm);
  void ttm_agp_tt_unpopulate(struct ttm_tt *ttm);

  #endif
  
  #endif