1/**************************************************************************
2 *
3 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD$");
30
31#include <dev/drm2/drmP.h>
32#include <dev/drm2/ttm/ttm_execbuf_util.h>
33#include <dev/drm2/ttm/ttm_bo_driver.h>
34#include <dev/drm2/ttm/ttm_placement.h>
35
36static void ttm_eu_backoff_reservation_locked(struct list_head *list)
37{
38	struct ttm_validate_buffer *entry;
39
40	list_for_each_entry(entry, list, head) {
41		struct ttm_buffer_object *bo = entry->bo;
42		if (!entry->reserved)
43			continue;
44
45		if (entry->removed) {
46			ttm_bo_add_to_lru(bo);
47			entry->removed = false;
48
49		}
50		entry->reserved = false;
51		atomic_set(&bo->reserved, 0);
52		wakeup(bo);
53	}
54}
55
56static void ttm_eu_del_from_lru_locked(struct list_head *list)
57{
58	struct ttm_validate_buffer *entry;
59
60	list_for_each_entry(entry, list, head) {
61		struct ttm_buffer_object *bo = entry->bo;
62		if (!entry->reserved)
63			continue;
64
65		if (!entry->removed) {
66			entry->put_count = ttm_bo_del_from_lru(bo);
67			entry->removed = true;
68		}
69	}
70}
71
72static void ttm_eu_list_ref_sub(struct list_head *list)
73{
74	struct ttm_validate_buffer *entry;
75
76	list_for_each_entry(entry, list, head) {
77		struct ttm_buffer_object *bo = entry->bo;
78
79		if (entry->put_count) {
80			ttm_bo_list_ref_sub(bo, entry->put_count, true);
81			entry->put_count = 0;
82		}
83	}
84}
85
86void ttm_eu_backoff_reservation(struct list_head *list)
87{
88	struct ttm_validate_buffer *entry;
89	struct ttm_bo_global *glob;
90
91	if (list_empty(list))
92		return;
93
94	entry = list_first_entry(list, struct ttm_validate_buffer, head);
95	glob = entry->bo->glob;
96	mtx_lock(&glob->lru_lock);
97	ttm_eu_backoff_reservation_locked(list);
98	mtx_unlock(&glob->lru_lock);
99}
100
101/*
102 * Reserve buffers for validation.
103 *
104 * If a buffer in the list is marked for CPU access, we back off and
105 * wait for that buffer to become free for GPU access.
106 *
107 * If a buffer is reserved for another validation, the validator with
108 * the highest validation sequence backs off and waits for that buffer
109 * to become unreserved. This prevents deadlocks when validating multiple
110 * buffers in different orders.
111 */
112
113int ttm_eu_reserve_buffers(struct list_head *list)
114{
115	struct ttm_bo_global *glob;
116	struct ttm_validate_buffer *entry;
117	int ret;
118	uint32_t val_seq;
119
120	if (list_empty(list))
121		return 0;
122
123	list_for_each_entry(entry, list, head) {
124		entry->reserved = false;
125		entry->put_count = 0;
126		entry->removed = false;
127	}
128
129	entry = list_first_entry(list, struct ttm_validate_buffer, head);
130	glob = entry->bo->glob;
131
132	mtx_lock(&glob->lru_lock);
133	val_seq = entry->bo->bdev->val_seq++;
134
135retry_locked:
136	list_for_each_entry(entry, list, head) {
137		struct ttm_buffer_object *bo = entry->bo;
138
139		/* already slowpath reserved? */
140		if (entry->reserved)
141			continue;
142
143		ret = ttm_bo_reserve_nolru(bo, true, true, true, val_seq);
144		switch (ret) {
145		case 0:
146			break;
147		case -EBUSY:
148			ttm_eu_del_from_lru_locked(list);
149			ret = ttm_bo_reserve_nolru(bo, true, false,
150						   true, val_seq);
151			if (!ret)
152				break;
153
154			if (unlikely(ret != -EAGAIN))
155				goto err;
156
157			/* fallthrough */
158		case -EAGAIN:
159			ttm_eu_backoff_reservation_locked(list);
160
161			/*
162			 * temporarily increase sequence number every retry,
163			 * to prevent us from seeing our old reservation
164			 * sequence when someone else reserved the buffer,
165			 * but hasn't updated the seq_valid/seqno members yet.
166			 */
167			val_seq = entry->bo->bdev->val_seq++;
168
169			ttm_eu_list_ref_sub(list);
170			ret = ttm_bo_reserve_slowpath_nolru(bo, true, val_seq);
171			if (unlikely(ret != 0)) {
172				mtx_unlock(&glob->lru_lock);
173				return ret;
174			}
175			entry->reserved = true;
176			if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
177				ret = -EBUSY;
178				goto err;
179			}
180			goto retry_locked;
181		default:
182			goto err;
183		}
184
185		entry->reserved = true;
186		if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
187			ret = -EBUSY;
188			goto err;
189		}
190	}
191
192	ttm_eu_del_from_lru_locked(list);
193	mtx_unlock(&glob->lru_lock);
194	ttm_eu_list_ref_sub(list);
195
196	return 0;
197
198err:
199	ttm_eu_backoff_reservation_locked(list);
200	mtx_unlock(&glob->lru_lock);
201	ttm_eu_list_ref_sub(list);
202	return ret;
203}
204
205void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
206{
207	struct ttm_validate_buffer *entry;
208	struct ttm_buffer_object *bo;
209	struct ttm_bo_global *glob;
210	struct ttm_bo_device *bdev;
211	struct ttm_bo_driver *driver;
212
213	if (list_empty(list))
214		return;
215
216	bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo;
217	bdev = bo->bdev;
218	driver = bdev->driver;
219	glob = bo->glob;
220
221	mtx_lock(&glob->lru_lock);
222	mtx_lock(&bdev->fence_lock);
223
224	list_for_each_entry(entry, list, head) {
225		bo = entry->bo;
226		entry->old_sync_obj = bo->sync_obj;
227		bo->sync_obj = driver->sync_obj_ref(sync_obj);
228		ttm_bo_unreserve_locked(bo);
229		entry->reserved = false;
230	}
231	mtx_unlock(&bdev->fence_lock);
232	mtx_unlock(&glob->lru_lock);
233
234	list_for_each_entry(entry, list, head) {
235		if (entry->old_sync_obj)
236			driver->sync_obj_unref(&entry->old_sync_obj);
237	}
238}
239