9.8
  *   ˆl–Ü4ý( ©³( 	Å€fàB¦-ÿÁƒyÑ9_†I|¥+ÅÄ "    /*
 * Copyright 2020 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) 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: Christian KÃ¶nig
 */

#ifndef _TTM_DEVICE_H_
#define _TTM_DEVICE_H_

#include <linux/types.h>
#include <linux/workqueue.h>
#include <drm/ttm/ttm_resource.h>
#include <drm/ttm/ttm_pool.h>

struct ttm_device;
struct ttm_placement;
struct ttm_buffer_object;
struct ttm_operation_ctx;

/**
 * struct ttm_global - Buffer object driver global data.
 */
extern struct ttm_global {

	/**
	 * @dummy_read_page: Pointer to a dummy page used for mapping requests
	 * of unpopulated pages. Constant after init.
	 */
	struct page *dummy_read_page;

	/**
	 * @device_list: List of buffer object devices. Protected by
	 * ttm_global_mutex.
	 */
	struct list_head device_list;

	/**
	 * @bo_count: Number of buffer objects allocated by devices.
	 */
	atomic_t bo_count;
} ttm_glob;

struct ttm_device_funcs {
	/**
	 * ttm_tt_create
	 *
	 * @bo: The buffer object to create the ttm for.
	 * @page_flags: Page flags as identified by TTM_TT_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_device *bdev,
			       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_device *bdev,
				  struct ttm_tt *ttm);

	/**
	 * ttm_tt_destroy
	 *
	 * @bdev: Pointer to a ttm device
	 * @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 (*ttm_tt_destroy)(struct ttm_device *bdev, struct ttm_tt *ttm);

	/**
	 * 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
	 * This should not cause multihop evictions, and the core will warn
	 * if one is proposed.
	 */

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

	/**
	 * struct ttm_bo_driver member move:
	 *
	 * @bo: the buffer to move