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 "ttm/ttm_execbuf_util.h"
29 #include "ttm/ttm_bo_driver.h"
30 #include "ttm/ttm_placement.h"
31 #include <linux/wait.h>
32 #include <linux/sched.h>
33 #include <linux/module.h>
34 
35 void ttm_eu_backoff_reservation(struct list_head *list)
36 {
37 	struct ttm_validate_buffer *entry;
38 
39 	list_for_each_entry(entry, list, head) {
40 		struct ttm_buffer_object *bo = entry->bo;
41 		if (!entry->reserved)
42 			continue;
43 
44 		entry->reserved = false;
45 		ttm_bo_unreserve(bo);
46 	}
47 }
48 EXPORT_SYMBOL(ttm_eu_backoff_reservation);
49 
50 /*
51  * Reserve buffers for validation.
52  *
53  * If a buffer in the list is marked for CPU access, we back off and
54  * wait for that buffer to become free for GPU access.
55  *
56  * If a buffer is reserved for another validation, the validator with
57  * the highest validation sequence backs off and waits for that buffer
58  * to become unreserved. This prevents deadlocks when validating multiple
59  * buffers in different orders.
60  */
61 
62 int ttm_eu_reserve_buffers(struct list_head *list, uint32_t val_seq)
63 {
64 	struct ttm_validate_buffer *entry;
65 	int ret;
66 
67 retry:
68 	list_for_each_entry(entry, list, head) {
69 		struct ttm_buffer_object *bo = entry->bo;
70 
71 		entry->reserved = false;
72 		ret = ttm_bo_reserve(bo, true, false, true, val_seq);
73 		if (ret != 0) {
74 			ttm_eu_backoff_reservation(list);
75 			if (ret == -EAGAIN) {
76 				ret = ttm_bo_wait_unreserved(bo, true);
77 				if (unlikely(ret != 0))
78 					return ret;
79 				goto retry;
80 			} else
81 				return ret;
82 		}
83 
84 		entry->reserved = true;
85 		if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
86 			ttm_eu_backoff_reservation(list);
87 			ret = ttm_bo_wait_cpu(bo, false);
88 			if (ret)
89 				return ret;
90 			goto retry;
91 		}
92 	}
93 	return 0;
94 }
95 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
96 
97 void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
98 {
99 	struct ttm_validate_buffer *entry;
100 
101 	list_for_each_entry(entry, list, head) {
102 		struct ttm_buffer_object *bo = entry->bo;
103 		struct ttm_bo_driver *driver = bo->bdev->driver;
104 		void *old_sync_obj;
105 
106 		spin_lock(&bo->lock);
107 		old_sync_obj = bo->sync_obj;
108 		bo->sync_obj = driver->sync_obj_ref(sync_obj);
109 		bo->sync_obj_arg = entry->new_sync_obj_arg;
110 		spin_unlock(&bo->lock);
111 		ttm_bo_unreserve(bo);
112 		entry->reserved = false;
113 		if (old_sync_obj)
114 			driver->sync_obj_unref(&old_sync_obj);
115 	}
116 }
117 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);
118