1/* SPDX-License-Identifier: GPL-2.0 OR MIT */
  2/**************************************************************************
  3 *
  4 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
  5 * All Rights Reserved.
  6 *
  7 * Permission is hereby granted, free of charge, to any person obtaining a
  8 * copy of this software and associated documentation files (the
  9 * "Software"), to deal in the Software without restriction, including
 10 * without limitation the rights to use, copy, modify, merge, publish,
 11 * distribute, sub license, and/or sell copies of the Software, and to
 12 * permit persons to whom the Software is furnished to do so, subject to
 13 * the following conditions:
 14 *
 15 * The above copyright notice and this permission notice (including the
 16 * next paragraph) shall be included in all copies or substantial portions
 17 * of the Software.
 18 *
 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 25 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 26 *
 27 **************************************************************************/
 28
 29#include <drm/ttm/ttm_execbuf_util.h>
 30#include <drm/ttm/ttm_bo.h>
 31
 32static void ttm_eu_backoff_reservation_reverse(struct list_head *list,
 33					      struct ttm_validate_buffer *entry)
 34{
 35	list_for_each_entry_continue_reverse(entry, list, head) {
 36		struct ttm_buffer_object *bo = entry->bo;
 37
 38		dma_resv_unlock(bo->base.resv);
 39	}
 40}
 41
 42void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
 43				struct list_head *list)
 44{
 45	struct ttm_validate_buffer *entry;
 46
 47	if (list_empty(list))
 48		return;
 49
 50	list_for_each_entry(entry, list, head) {
 51		struct ttm_buffer_object *bo = entry->bo;
 52
 53		ttm_bo_move_to_lru_tail_unlocked(bo);
 54		dma_resv_unlock(bo->base.resv);
 55	}
 56
 57	if (ticket)
 58		ww_acquire_fini(ticket);
 59}
 60EXPORT_SYMBOL(ttm_eu_backoff_reservation);
 61
 62/*
 63 * Reserve buffers for validation.
 64 *
 65 * If a buffer in the list is marked for CPU access, we back off and
 66 * wait for that buffer to become free for GPU access.
 67 *
 68 * If a buffer is reserved for another validation, the validator with
 69 * the highest validation sequence backs off and waits for that buffer
 70 * to become unreserved. This prevents deadlocks when validating multiple
 71 * buffers in different orders.
 72 */
 73
 74int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
 75			   struct list_head *list, bool intr,
 76			   struct list_head *dups)
 77{
 78	struct ttm_validate_buffer *entry;
 79	int ret;
 80
 81	if (list_empty(list))
 82		return 0;
 83
 84	if (ticket)
 85		ww_acquire_init(ticket, &reservation_ww_class);
 86
 87	list_for_each_entry(entry, list, head) {
 88		struct ttm_buffer_object *bo = entry->bo;
 89		unsigned int num_fences;
 90
 91		ret = ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
 92		if (ret == -EALREADY && dups) {
 93			struct ttm_validate_buffer *safe = entry;
 94			entry = list_prev_entry(entry, head);
 95			list_del(&safe->head);
 96			list_add(&safe->head, dups);
 97			continue;
 98		}
 99
100		num_fences = max(entry->num_shared, 1u);
101		if (!ret) {
102			ret = dma_resv_reserve_fences(bo->base.resv,
103						      num_fences);
104			if (!ret)
105				continue;
106		}
107
108		/* uh oh, we lost out, drop every reservation and try
109		 * to only reserve this buffer, then start over if
110		 * this succeeds.
111		 */
112		ttm_eu_backoff_reservation_reverse(list, entry);
113
114		if (ret == -EDEADLK) {
115			ret = ttm_bo_reserve_slowpath(bo, intr, ticket);
116		}
117
118		if (!ret)
119			ret = dma_resv_reserve_fences(bo->base.resv,
120						      num_fences);
121
122		if (unlikely(ret != 0)) {
123			if (ticket) {
124				ww_acquire_done(ticket);
125				ww_acquire_fini(ticket);
126			}
127			return ret;
128		}
129
130		/* move this item to the front of the list,
131		 * forces correct iteration of the loop without keeping track
132		 */
133		list_del(&entry->head);
134		list_add(&entry->head, list);
135	}
136
137	return 0;
138}
139EXPORT_SYMBOL(ttm_eu_reserve_buffers);
140
141void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
142				 struct list_head *list,
143				 struct dma_fence *fence)
144{
145	struct ttm_validate_buffer *entry;
146
147	if (list_empty(list))
148		return;
149
150	list_for_each_entry(entry, list, head) {
151		struct ttm_buffer_object *bo = entry->bo;
152
153		dma_resv_add_fence(bo->base.resv, fence, entry->num_shared ?
154				   DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE);
155		ttm_bo_move_to_lru_tail_unlocked(bo);
156		dma_resv_unlock(bo->base.resv);
157	}
158	if (ticket)
159		ww_acquire_fini(ticket);
160}
161EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);