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_driver.h>
31#include <drm/ttm/ttm_placement.h>
32#include <linux/wait.h>
33#include <linux/sched.h>
34#include <linux/module.h>
35
36static void ttm_eu_backoff_reservation_reverse(struct list_head *list,
37					      struct ttm_validate_buffer *entry)
38{
39	list_for_each_entry_continue_reverse(entry, list, head) {
40		struct ttm_buffer_object *bo = entry->bo;
41
42		dma_resv_unlock(bo->base.resv);
43	}
44}
45
46void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
47				struct list_head *list)
48{
49	struct ttm_validate_buffer *entry;
50
51	if (list_empty(list))
52		return;
53
54	spin_lock(&ttm_bo_glob.lru_lock);
55	list_for_each_entry(entry, list, head) {
56		struct ttm_buffer_object *bo = entry->bo;
57
58		ttm_bo_move_to_lru_tail(bo, NULL);
59		dma_resv_unlock(bo->base.resv);
60	}
61	spin_unlock(&ttm_bo_glob.lru_lock);
62
63	if (ticket)
64		ww_acquire_fini(ticket);
65}
66EXPORT_SYMBOL(ttm_eu_backoff_reservation);
67
68/*
69 * Reserve buffers for validation.
70 *
71 * If a buffer in the list is marked for CPU access, we back off and
72 * wait for that buffer to become free for GPU access.
73 *
74 * If a buffer is reserved for another validation, the validator with
75 * the highest validation sequence backs off and waits for that buffer
76 * to become unreserved. This prevents deadlocks when validating multiple
77 * buffers in different orders.
78 */
79
80int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
81			   struct list_head *list, bool intr,
82			   struct list_head *dups)
83{
84	struct ttm_validate_buffer *entry;
85	int ret;
86
87	if (list_empty(list))
88		return 0;
89
90	if (ticket)
91		ww_acquire_init(ticket, &reservation_ww_class);
92
93	list_for_each_entry(entry, list, head) {
94		struct ttm_buffer_object *bo = entry->bo;
95
96		ret = ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
97		if (ret == -EALREADY && dups) {
98			struct ttm_validate_buffer *safe = entry;
99			entry = list_prev_entry(entry, head);
100			list_del(&safe->head);
101			list_add(&safe->head, dups);
102			continue;
103		}
104
105		if (!ret) {
106			if (!entry->num_shared)
107				continue;
108
109			ret = dma_resv_reserve_shared(bo->base.resv,
110								entry->num_shared);
111			if (!ret)
112				continue;
113		}
114
115		/* uh oh, we lost out, drop every reservation and try
116		 * to only reserve this buffer, then start over if
117		 * this succeeds.
118		 */
119		ttm_eu_backoff_reservation_reverse(list, entry);
120
121		if (ret == -EDEADLK) {
122			ret = ttm_bo_reserve_slowpath(bo, intr, ticket);
123		}
124
125		if (!ret && entry->num_shared)
126			ret = dma_resv_reserve_shared(bo->base.resv,
127								entry->num_shared);
128
129		if (unlikely(ret != 0)) {
130			if (ticket) {
131				ww_acquire_done(ticket);
132				ww_acquire_fini(ticket);
133			}
134			return ret;
135		}
136
137		/* move this item to the front of the list,
138		 * forces correct iteration of the loop without keeping track
139		 */
140		list_del(&entry->head);
141		list_add(&entry->head, list);
142	}
143
144	return 0;
145}
146EXPORT_SYMBOL(ttm_eu_reserve_buffers);
147
148void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
149				 struct list_head *list,
150				 struct dma_fence *fence)
151{
152	struct ttm_validate_buffer *entry;
153
154	if (list_empty(list))
155		return;
156
157	spin_lock(&ttm_bo_glob.lru_lock);
158	list_for_each_entry(entry, list, head) {
159		struct ttm_buffer_object *bo = entry->bo;
160
161		if (entry->num_shared)
162			dma_resv_add_shared_fence(bo->base.resv, fence);
163		else
164			dma_resv_add_excl_fence(bo->base.resv, fence);
165		ttm_bo_move_to_lru_tail(bo, NULL);
166		dma_resv_unlock(bo->base.resv);
167	}
168	spin_unlock(&ttm_bo_glob.lru_lock);
169	if (ticket)
170		ww_acquire_fini(ticket);
171}
172EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);
173