Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 872 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 000000000..3234cc322
--- /dev/null
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -0,0 +1,872 @@
+/**************************************************************************
+ *
+ * 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 <drm/drm_mm.h>
+#include <drm/drm_global.h>
+#include <drm/drm_vma_manager.h>
+#include <linux/workqueue.h>
+#include <linux/fs.h>
+#include <linux/spinlock.h>
+#include <linux/reservation.h>
+
+#include "ttm_bo_api.h"
+#include "ttm_memory.h"
+#include "ttm_module.h"
+#include "ttm_placement.h"
+#include "ttm_tt.h"
+
+#define TTM_MAX_BO_PRIORITY	4U
+
+#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.
+	 * @flags: Additional placement flags.
+	 * @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,
+			 const struct ttm_place *place,
+			 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.
+	 * @printer: 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,
+		      struct drm_printer *printer);
+};
+
+/**
+ * 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
+ * @move_lock: lock for move fence
+ * static information. bdev::driver::io_mem_free is never used.
+ * @lru: The lru list for this memory type.
+ * @move: The fence of the last pipelined move operation.
+ *
+ * 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;
+	uint64_t gpu_offset; /* GPU address space is independent of CPU word size */
+	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;
+	spinlock_t move_lock;
+
+	/*
+	 * Protected by @io_reserve_mutex:
+	 */
+
+	struct list_head io_reserve_lru;
+
+	/*
+	 * Protected by the global->lru_lock.
+	 */
+
+	struct list_head lru[TTM_MAX_BO_PRIORITY];
+
+	/*
+	 * Protected by @move_lock.
+	 */
+	struct dma_fence *move;
+};
+
+/**
+ * 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.
+ */
+
+struct ttm_bo_driver {
+	/**
+	 * ttm_tt_create
+	 *
+	 * @bo: The buffer object to create the ttm for.
+	 * @page_flags: Page flags as identified by TTM_PAGE_FLAG_XX flags.
+	 *
+	 * 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_buffer_object *bo,
+					uint32_t page_flags);
+
+	/**
+	 * 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,
+			struct ttm_operation_ctx *ctx);
+
+	/**
+	 * 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 eviction_valuable
+	 *
+	 * @bo: the buffer object to be evicted
+	 * @place: placement we need room for
+	 *
+	 * Check with the driver if it is valuable to evict a BO to make room
+	 * for a certain placement.
+	 */
+	bool (*eviction_valuable)(struct ttm_buffer_object *bo,
+				  const struct ttm_place *place);
+	/**
+	 * 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
+	 * @ctx: context for this move with parameters
+	 * @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,
+		    struct ttm_operation_ctx *ctx,
+		    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);
+
+	/**
+	 * Hook to notify driver about a driver move so it
+	 * can do tiling things and book-keeping.
+	 *
+	 * @evict: whether this move is evicting the buffer from the graphics
+	 * address space
+	 */
+	void (*move_notify)(struct ttm_buffer_object *bo,
+			    bool evict,
+			    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);
+
+	/**
+	 * Return the pfn for a given page_offset inside the BO.
+	 *
+	 * @bo: the BO to look up the pfn for
+	 * @page_offset: the offset to look up
+	 */
+	unsigned long (*io_mem_pfn)(struct ttm_buffer_object *bo,
+				    unsigned long page_offset);
+
+	/**
+	 * Read/write memory buffers for ptrace access
+	 *
+	 * @bo: the BO to access
+	 * @offset: the offset from the start of the BO
+	 * @buf: pointer to source/destination buffer
+	 * @len: number of bytes to copy
+	 * @write: whether to read (0) from or write (non-0) to BO
+	 *
+	 * If successful, this function should return the number of
+	 * bytes copied, -EIO otherwise. If the number of bytes
+	 * returned is < len, the function may be called again with
+	 * the remainder of the buffer to copy.
+	 */
+	int (*access_memory)(struct ttm_buffer_object *bo, unsigned long offset,
+			     void *buf, int len, int write);
+};
+
+/**
+ * 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 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[TTM_MAX_BO_PRIORITY];
+
+	/**
+	 * Internal protection.
+	 */
+	atomic_t bo_count;
+};
+
+
+#define TTM_NUM_MEM_TYPES 8
+
+/**
+ * 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.
+ * @vma_manager: Address space manager
+ * lru_lock: Spinlock that protects the buffer+device lru lists and
+ * ddestroy lists.
+ * @dev_mapping: A pointer to the struct address_space representing the
+ * device address space.
+ * @wq: Work queue structure for the delayed delete workqueue.
+ * @no_retry: Don't retry allocation if it fails
+ *
+ */
+
+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;
+	struct ttm_mem_type_manager man[TTM_NUM_MEM_TYPES];
+
+	/*
+	 * Protected by internal locks.
+	 */
+	struct drm_vma_offset_manager vma_manager;
+
+	/*
+	 * Protected by the global:lru lock.
+	 */
+	struct list_head ddestroy;
+
+	/*
+	 * Protected by load / firstopen / lastclose /unload sync.
+	 */
+
+	struct address_space *dev_mapping;
+
+	/*
+	 * Internal protection.
+	 */
+
+	struct delayed_work wq;
+
+	bool need_dma32;
+
+	bool no_retry;
+};
+
+/**
+ * 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_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.
+ */
+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_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.
+ */
+int ttm_bo_mem_space(struct ttm_buffer_object *bo,
+		     struct ttm_placement *placement,
+		     struct ttm_mem_reg *mem,
+		     struct ttm_operation_ctx *ctx);
+
+void ttm_bo_mem_put(struct ttm_buffer_object *bo, struct ttm_mem_reg *mem);
+void ttm_bo_mem_put_locked(struct ttm_buffer_object *bo,
+			   struct ttm_mem_reg *mem);
+
+void ttm_bo_global_release(struct drm_global_reference *ref);
+int ttm_bo_global_init(struct drm_global_reference *ref);
+
+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.
+ * @mapping: The address space to use for this bo.
+ * @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.
+ */
+int ttm_bo_device_init(struct ttm_bo_device *bdev, struct ttm_bo_global *glob,
+		       struct ttm_bo_driver *driver,
+		       struct address_space *mapping,
+		       uint64_t file_page_offset, bool need_dma32);
+
+/**
+ * ttm_bo_unmap_virtual
+ *
+ * @bo: tear down the virtual mappings for this BO
+ */
+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.
+ */
+void ttm_bo_unmap_virtual_locked(struct ttm_buffer_object *bo);
+
+int ttm_mem_io_reserve_vm(struct ttm_buffer_object *bo);
+void ttm_mem_io_free_vm(struct ttm_buffer_object *bo);
+int ttm_mem_io_lock(struct ttm_mem_type_manager *man, bool interruptible);
+void ttm_mem_io_unlock(struct ttm_mem_type_manager *man);
+
+void ttm_bo_del_sub_from_lru(struct ttm_buffer_object *bo);
+void ttm_bo_add_to_lru(struct ttm_buffer_object *bo);
+
+/**
+ * __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.
+ * @ticket: ticket used to acquire the ww_mutex.
+ *
+ * Will not remove reserved buffers from the lru lists.
+ * Otherwise identical to ttm_bo_reserve.
+ *
+ * Returns:
+ * -EDEADLK: 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
+ * -EALREADY: Bo already reserved using @ticket. This error code will only
+ * be returned if @use_ticket is set to true.
+ */
+static inline int __ttm_bo_reserve(struct ttm_buffer_object *bo,
+				   bool interruptible, bool no_wait,
+				   struct ww_acquire_ctx *ticket)
+{
+	int ret = 0;
+
+	if (no_wait) {
+		bool success;
+		if (WARN_ON(ticket))
+			return -EBUSY;
+
+		success = reservation_object_trylock(bo->resv);
+		return success ? 0 : -EBUSY;
+	}
+
+	if (interruptible)
+		ret = reservation_object_lock_interruptible(bo->resv, ticket);
+	else
+		ret = reservation_object_lock(bo->resv, ticket);
+	if (ret == -EINTR)
+		return -ERESTARTSYS;
+	return ret;
+}
+
+/**
+ * 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.
+ * @ticket: ticket used to acquire the ww_mutex.
+ *
+ * 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:
+ * 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_ticket == 1 and @ticket->stamp == 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 -EDEADLK. Otherwise it sleeps
+ * waiting for the buffer to become unreserved, after which it retries
+ * reserving.
+ * The caller should, when receiving an -EDEADLK 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:
+ * -EDEADLK: 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
+ * -EALREADY: Bo already reserved using @ticket. This error code will only
+ * be returned if @use_ticket is set to true.
+ */
+static inline int ttm_bo_reserve(struct ttm_buffer_object *bo,
+				 bool interruptible, bool no_wait,
+				 struct ww_acquire_ctx *ticket)
+{
+	int ret;
+
+	WARN_ON(!kref_read(&bo->kref));
+
+	ret = __ttm_bo_reserve(bo, interruptible, no_wait, ticket);
+	if (likely(ret == 0))
+		ttm_bo_del_sub_from_lru(bo);
+
+	return ret;
+}
+
+/**
+ * ttm_bo_reserve_slowpath:
+ * @bo: A pointer to a struct ttm_buffer_object.
+ * @interruptible: Sleep interruptible if waiting.
+ * @sequence: Set (@bo)->sequence to this value after lock
+ *
+ * This is called after ttm_bo_reserve returns -EAGAIN and we backed off
+ * from all our other reservations. Because there are no other reservations
+ * held by us, this function cannot deadlock any more.
+ */
+static inline int ttm_bo_reserve_slowpath(struct ttm_buffer_object *bo,
+					  bool interruptible,
+					  struct ww_acquire_ctx *ticket)
+{
+	int ret = 0;
+
+	WARN_ON(!kref_read(&bo->kref));
+
+	if (interruptible)
+		ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock,
+						       ticket);
+	else
+		ww_mutex_lock_slow(&bo->resv->lock, ticket);
+
+	if (likely(ret == 0))
+		ttm_bo_del_sub_from_lru(bo);
+	else if (ret == -EINTR)
+		ret = -ERESTARTSYS;
+
+	return ret;
+}
+
+/**
+ * ttm_bo_unreserve
+ *
+ * @bo: A pointer to a struct ttm_buffer_object.
+ *
+ * Unreserve a previous reservation of @bo.
+ */
+static inline void ttm_bo_unreserve(struct ttm_buffer_object *bo)
+{
+	if (!(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) {
+		spin_lock(&bo->bdev->glob->lru_lock);
+		ttm_bo_add_to_lru(bo);
+		spin_unlock(&bo->bdev->glob->lru_lock);
+	}
+	reservation_object_unlock(bo->resv);
+}
+
+/*
+ * ttm_bo_util.c
+ */
+
+int ttm_mem_io_reserve(struct ttm_bo_device *bdev,
+		       struct ttm_mem_reg *mem);
+void ttm_mem_io_free(struct ttm_bo_device *bdev,
+		     struct ttm_mem_reg *mem);
+/**
+ * ttm_bo_move_ttm
+ *
+ * @bo: A pointer to a struct ttm_buffer_object.
+ * @interruptible: Sleep interruptible if waiting.
+ * @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.
+ */
+
+int ttm_bo_move_ttm(struct ttm_buffer_object *bo,
+		    struct ttm_operation_ctx *ctx,
+		    struct ttm_mem_reg *new_mem);
+
+/**
+ * ttm_bo_move_memcpy
+ *
+ * @bo: A pointer to a struct ttm_buffer_object.
+ * @interruptible: Sleep interruptible if waiting.
+ * @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.
+ */
+
+int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
+		       struct ttm_operation_ctx *ctx,
+		       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.
+ */
+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.
+ * @fence: A fence object that signals when moving is complete.
+ * @evict: This is an evict move. Don't return until the buffer is idle.
+ * @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.
+ */
+int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
+			      struct dma_fence *fence, bool evict,
+			      struct ttm_mem_reg *new_mem);
+
+/**
+ * ttm_bo_pipeline_move.
+ *
+ * @bo: A pointer to a struct ttm_buffer_object.
+ * @fence: A fence object that signals when moving is complete.
+ * @evict: This is an evict move. Don't return until the buffer is idle.
+ * @new_mem: struct ttm_mem_reg indicating where to move.
+ *
+ * Function for pipelining accelerated moves. Either free the memory
+ * immediately or hang it on a temporary buffer object.
+ */
+int ttm_bo_pipeline_move(struct ttm_buffer_object *bo,
+			 struct dma_fence *fence, bool evict,
+			 struct ttm_mem_reg *new_mem);
+
+/**
+ * ttm_bo_pipeline_gutting.
+ *
+ * @bo: A pointer to a struct ttm_buffer_object.
+ *
+ * Pipelined gutting a BO of it's backing store.
+ */
+int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo);
+
+/**
+ * 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.
+ */
+pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp);
+
+extern const struct ttm_mem_type_manager_func ttm_bo_manager_func;
+
+#endif