drm: Add the TTM GPU memory manager subsystem.

TTM is a GPU memory manager subsystem designed for use with GPU
devices with various memory types (On-card VRAM, AGP,
PCI apertures etc.). It's essentially a helper library that assists
the DRM driver in creating and managing persistent buffer objects.

TTM manages placement of data and CPU map setup and teardown on
data movement. It can also optionally manage synchronization of
data on a per-buffer-object level.

TTM takes care to provide an always valid virtual user-space address
to a buffer object which makes user-space sub-allocation of
big buffer objects feasible.

TTM uses a fine-grained per buffer-object locking scheme, taking
care to release all relevant locks when waiting for the GPU.
Although this implies some locking overhead, it's probably a big
win for devices with multiple command submission mechanisms, since
the lock contention will be minimal.

TTM can be used with whatever user-space interface the driver
chooses, including GEM. It's used by the upcoming Radeon KMS DRM driver
and is also the GPU memory management core of various new experimental
DRM drivers.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 867 insertions, 0 deletions

diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
new file mode 100644
index 0000000..62ed733
--- /dev/null
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -0,0 +1,867 @@
+/**************************************************************************
+ *
+ * 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 "drm_mm.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 populate
+	 *
+	 * @backend: Pointer to a struct ttm_backend.
+	 * @num_pages: Number of pages to populate.
+	 * @pages: Array of pointers to ttm pages.
+	 * @dummy_read_page: Page to be used instead of NULL pages in the
+	 * array @pages.
+	 *
+	 * Populate the backend with ttm pages. Depending on the backend,
+	 * it may or may not copy the @pages array.
+	 */
+	int (*populate) (struct ttm_backend *backend,
+			 unsigned long num_pages, struct page **pages,
+			 struct page *dummy_read_page);
+	/**
+	 * struct ttm_backend_func member clear
+	 *
+	 * @backend: Pointer to a struct ttm_backend.
+	 *
+	 * This is an "unpopulate" function. Release all resources
+	 * allocated with populate.
+	 */
+	void (*clear) (struct ttm_backend *backend);
+
+	/**
+	 * struct ttm_backend_func member bind
+	 *
+	 * @backend: Pointer to a struct ttm_backend.
+	 * @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_backend *backend, struct ttm_mem_reg *bo_mem);
+
+	/**
+	 * struct ttm_backend_func member unbind
+	 *
+	 * @backend: Pointer to a struct ttm_backend.
+	 *
+	 * Unbind previously bound backend pages. This function should be
+	 * able to handle differences between aperture- and system page sizes.
+	 */
+	int (*unbind) (struct ttm_backend *backend);
+
+	/**
+	 * struct ttm_backend_func member destroy
+	 *
+	 * @backend: Pointer to a struct ttm_backend.
+	 *
+	 * Destroy the backend.
+	 */
+	void (*destroy) (struct ttm_backend *backend);
+};
+
+/**
+ * struct ttm_backend
+ *
+ * @bdev: Pointer to a struct ttm_bo_device.
+ * @flags: For driver use.
+ * @func: Pointer to a struct ttm_backend_func that describes
+ * the backend methods.
+ *
+ */
+
+struct ttm_backend {
+	struct ttm_bo_device *bdev;
+	uint32_t flags;
+	struct ttm_backend_func *func;
+};
+
+#define TTM_PAGE_FLAG_VMALLOC         (1 << 0)
+#define TTM_PAGE_FLAG_USER            (1 << 1)
+#define TTM_PAGE_FLAG_USER_DIRTY      (1 << 2)
+#define TTM_PAGE_FLAG_WRITE           (1 << 3)
+#define TTM_PAGE_FLAG_SWAPPED         (1 << 4)
+#define TTM_PAGE_FLAG_PERSISTANT_SWAP (1 << 5)
+#define TTM_PAGE_FLAG_ZERO_ALLOC      (1 << 6)
+
+enum ttm_caching_state {
+	tt_uncached,
+	tt_wc,
+	tt_cached
+};
+
+/**
+ * struct ttm_tt
+ *
+ * @dummy_read_page: Page to map where the ttm_tt page array contains a NULL
+ * pointer.
+ * @pages: Array of pages backing the data.
+ * @first_himem_page: Himem pages are put last in the page array, which
+ * enables us to run caching attribute changes on only the first part
+ * of the page array containing lomem pages. This is the index of the
+ * first himem page.
+ * @last_lomem_page: Index of the last lomem page in the page array.
+ * @num_pages: Number of pages in the page array.
+ * @bdev: Pointer to the current struct ttm_bo_device.
+ * @be: Pointer to the ttm backend.
+ * @tsk: The task for user ttm.
+ * @start: virtual address for user ttm.
+ * @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 page *dummy_read_page;
+	struct page **pages;
+	long first_himem_page;
+	long last_lomem_page;
+	uint32_t page_flags;
+	unsigned long num_pages;
+	struct ttm_bo_device *bdev;
+	struct ttm_backend *be;
+	struct task_struct *tsk;
+	unsigned long start;
+	struct file *swap_storage;
+	enum ttm_caching_state caching_state;
+	enum {
+		tt_bound,
+		tt_unbound,
+		tt_unpopulated,
+	} state;
+};
+
+#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_NEEDS_IOREMAP (1 << 2)	/* Fixed memory needs ioremap
+						   before kernel access. */
+#define TTM_MEMTYPE_FLAG_CMA           (1 << 3)	/* Can't map aperture */
+
+/**
+ * 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.
+ * @io_offset: The io_offset of the first managed page of IO memory or
+ * the first managed location in an aperture. For TTM_MEMTYPE_FLAG_CMA
+ * memory, this should be set to NULL.
+ * @io_size: The size of a managed IO region (fixed memory or aperture).
+ * @io_addr: Virtual kernel address if the io region is pre-mapped. For
+ * TTM_MEMTYPE_FLAG_NEEDS_IOREMAP there is no pre-mapped io map and
+ * @io_addr should be set to NULL.
+ * @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.
+ * @manager: The range manager used for this memory type. FIXME: If the aperture
+ * has a page size different from the underlying system, the granularity
+ * of this manager should take care of this. But the range allocating code
+ * in ttm_bo.c needs to be modified for this.
+ * @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 {
+
+	/*
+	 * No protection. Constant from start.
+	 */
+
+	bool has_type;
+	bool use_type;
+	uint32_t flags;
+	unsigned long gpu_offset;
+	unsigned long io_offset;
+	unsigned long io_size;
+	void *io_addr;
+	uint64_t size;
+	uint32_t available_caching;
+	uint32_t default_caching;
+
+	/*
+	 * Protected by the bdev->lru_lock.
+	 * TODO: Consider one lru_lock per ttm_mem_type_manager.
+	 * Plays ill with list removal, though.
+	 */
+
+	struct drm_mm manager;
+	struct list_head lru;
+};
+
+/**
+ * struct ttm_bo_driver
+ *
+ * @mem_type_prio: Priority array of memory types to place a buffer object in
+ * if it fits without evicting buffers from any of these memory types.
+ * @mem_busy_prio: Priority array of memory types to place a buffer object in
+ * if it needs to evict buffers to make room.
+ * @num_mem_type_prio: Number of elements in the @mem_type_prio array.
+ * @num_mem_busy_prio: Number of elements in the @num_mem_busy_prio array.
+ * @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 {
+	const uint32_t *mem_type_prio;
+	const uint32_t *mem_busy_prio;
+	uint32_t num_mem_type_prio;
+	uint32_t num_mem_busy_prio;
+
+	/**
+	 * struct ttm_bo_driver member create_ttm_backend_entry
+	 *
+	 * @bdev: The buffer object device.
+	 *
+	 * Create a driver specific struct ttm_backend.
+	 */
+
+	struct ttm_backend *(*create_ttm_backend_entry)
+	 (struct ttm_bo_device *bdev);
+
+	/**
+	 * 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
+	 */
+
+	 uint32_t(*evict_flags) (struct ttm_buffer_object *bo);
+	/**
+	 * 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, 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);
+};
+
+#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.
+ *
+ * @mem_glob: Pointer to a struct ttm_mem_global object for accounting.
+ * @driver: Pointer to a struct ttm_bo_driver struct setup by the driver.
+ * @count: Current number of buffer object.
+ * @pages: Current number of pinned pages.
+ * @dummy_read_page: Pointer to a dummy page used for mapping requests
+ * of unpopulated pages.
+ * @shrink: A shrink callback object used for buffre object swap.
+ * @ttm_bo_extra_size: Extra size (sizeof(struct ttm_buffer_object) excluded)
+ * used by a buffer object. This is excluding page arrays and backing pages.
+ * @ttm_bo_size: This is @ttm_bo_extra_size + sizeof(struct ttm_buffer_object).
+ * @man: An array of mem_type_managers.
+ * @addr_space_mm: Range manager for the device address space.
+ * lru_lock: Spinlock that protects the buffer+device lru lists and
+ * ddestroy lists.
+ * @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 ttm_mem_global *mem_glob;
+	struct ttm_bo_driver *driver;
+	struct page *dummy_read_page;
+	struct ttm_mem_shrink shrink;
+
+	size_t ttm_bo_extra_size;
+	size_t ttm_bo_size;
+
+	rwlock_t vm_lock;
+	/*
+	 * Protected by the vm lock.
+	 */
+	struct ttm_mem_type_manager man[TTM_NUM_MEM_TYPES];
+	struct rb_root addr_space_rb;
+	struct drm_mm addr_space_mm;
+
+	/*
+	 * Might want to change this to one lock per manager.
+	 */
+	spinlock_t lru_lock;
+	/*
+	 * Protected by the lru lock.
+	 */
+	struct list_head ddestroy;
+	struct list_head swap_lru;
+
+	/*
+	 * Protected by load / firstopen / lastclose /unload sync.
+	 */
+
+	bool nice_mode;
+	struct address_space *dev_mapping;
+
+	/*
+	 * Internal protection.
+	 */
+
+	struct delayed_work wq;
+};
+
+/**
+ * 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_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.
+ */
+extern 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_set_user:
+ *
+ * @ttm: The struct ttm_tt to populate.
+ * @tsk: A struct task_struct for which @start is a valid user-space address.
+ * @start: A valid user-space address.
+ * @num_pages: Size in pages of the user memory area.
+ *
+ * Populate a struct ttm_tt with a user-space memory area after first pinning
+ * the pages backing it.
+ * Returns:
+ * !0: Error.
+ */
+
+extern int ttm_tt_set_user(struct ttm_tt *ttm,
+			   struct task_struct *tsk,
+			   unsigned long start, unsigned long num_pages);
+
+/**
+ * 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 a 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_ttm_destroy:
+ *
+ * @ttm: The struct ttm_tt.
+ * @index: Index of the desired page.
+ *
+ * Return a pointer to the struct page backing @ttm at page
+ * index @index. If the page is unpopulated, one will be allocated to
+ * populate that index.
+ *
+ * Returns:
+ * NULL on OOM.
+ */
+extern struct page *ttm_tt_get_page(struct ttm_tt *ttm, int index);
+
+/**
+ * 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 *persistant_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: Don't sleep waiting for space to become available.
+ *
+ * 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.
+ * -ERESTART: An interruptible sleep was interrupted by a signal.
+ */
+extern int ttm_bo_mem_space(struct ttm_buffer_object *bo,
+			    uint32_t proposed_placement,
+			    struct ttm_mem_reg *mem,
+			    bool interruptible, bool no_wait);
+/**
+ * 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).
+ * -ERESTART: An interruptible sleep was interrupted by a signal.
+ */
+
+extern int ttm_bo_wait_cpu(struct ttm_buffer_object *bo, bool no_wait);
+
+/**
+ * ttm_bo_pci_offset - Get the PCI offset for the buffer object memory.
+ *
+ * @bo Pointer to a struct ttm_buffer_object.
+ * @bus_base On return the base of the PCI region
+ * @bus_offset On return the byte offset into the PCI region
+ * @bus_size On return the byte size of the buffer object or zero if
+ * the buffer object memory is not accessible through a PCI region.
+ *
+ * Returns:
+ * -EINVAL if the buffer object is currently not mappable.
+ * 0 otherwise.
+ */
+
+extern int ttm_bo_pci_offset(struct ttm_bo_device *bdev,
+			     struct ttm_mem_reg *mem,
+			     unsigned long *bus_base,
+			     unsigned long *bus_offset,
+			     unsigned long *bus_size);
+
+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.
+ * @mem_global: A pointer to an initialized struct ttm_mem_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_mem_global *mem_glob,
+			      struct ttm_bo_driver *driver,
+			      uint64_t file_page_offset);
+
+/**
+ * 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
+ * occuring:
+ * 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).
+ * -ERESTART: A wait for the buffer to become unreserved was interrupted by
+ * a signal. Release all buffer reservations and return to user-space.
+ */
+extern int ttm_bo_reserve(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_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_block_reservation
+ *
+ * @bo: A pointer to a struct ttm_buffer_object.
+ * @interruptible: Use interruptible sleep when waiting.
+ * @no_wait: Don't sleep, but rather return -EBUSY.
+ *
+ * Block reservation for validation by simply reserving the buffer.
+ * This is intended for single buffer use only without eviction,
+ * and thus needs no deadlock protection.
+ *
+ * Returns:
+ * -EBUSY: If no_wait == 1 and the buffer is already reserved.
+ * -ERESTART: If interruptible == 1 and the process received a signal
+ * while sleeping.
+ */
+extern int ttm_bo_block_reservation(struct ttm_buffer_object *bo,
+				    bool interruptible, bool no_wait);
+
+/**
+ * ttm_bo_unblock_reservation
+ *
+ * @bo: A pointer to a struct ttm_buffer_object.
+ *
+ * Unblocks reservation leaving lru lists untouched.
+ */
+extern void ttm_bo_unblock_reservation(struct ttm_buffer_object *bo);
+
+/*
+ * 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: Never sleep, but rather return with -EBUSY.
+ * @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,
+			   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: Never sleep, but rather return with -EBUSY.
+ * @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, 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: Never sleep, but rather return with -EBUSY.
+ * @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,
+				     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(enum ttm_caching_state c_state, pgprot_t tmp);
+
+#if (defined(CONFIG_AGP) || (defined(CONFIG_AGP_MODULE) && defined(MODULE)))
+#define TTM_HAS_AGP
+#include <linux/agp_backend.h>
+
+/**
+ * ttm_agp_backend_init
+ *
+ * @bdev: Pointer to a struct ttm_bo_device.
+ * @bridge: The agp bridge this device is sitting on.
+ *
+ * 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_backend *ttm_agp_backend_init(struct ttm_bo_device *bdev,
+						struct agp_bridge_data *bridge);
+#endif
+
+#endif