1 /*
2 * Copyright 2015 Advanced Micro Devices, Inc.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
21 *
22 */
23
24 #include <linux/kthread.h>
25 #include <linux/module.h>
26 #include <linux/sched.h>
27 #include <linux/slab.h>
28 #include <linux/wait.h>
29
30 #include <drm/gpu_scheduler.h>
31
32 static struct kmem_cache *sched_fence_slab;
33
drm_sched_fence_slab_init(void)34 static int __init drm_sched_fence_slab_init(void)
35 {
36 sched_fence_slab = kmem_cache_create(
37 "drm_sched_fence", sizeof(struct drm_sched_fence), 0,
38 SLAB_HWCACHE_ALIGN, NULL);
39 if (!sched_fence_slab)
40 return -ENOMEM;
41
42 return 0;
43 }
44
drm_sched_fence_slab_fini(void)45 static void __exit drm_sched_fence_slab_fini(void)
46 {
47 rcu_barrier();
48 kmem_cache_destroy(sched_fence_slab);
49 }
50
drm_sched_fence_scheduled(struct drm_sched_fence * fence)51 void drm_sched_fence_scheduled(struct drm_sched_fence *fence)
52 {
53 int ret = dma_fence_signal(&fence->scheduled);
54
55 if (!ret)
56 DMA_FENCE_TRACE(&fence->scheduled,
57 "signaled from irq context\n");
58 else
59 DMA_FENCE_TRACE(&fence->scheduled,
60 "was already signaled\n");
61 }
62
drm_sched_fence_finished(struct drm_sched_fence * fence)63 void drm_sched_fence_finished(struct drm_sched_fence *fence)
64 {
65 int ret = dma_fence_signal(&fence->finished);
66
67 if (!ret)
68 DMA_FENCE_TRACE(&fence->finished,
69 "signaled from irq context\n");
70 else
71 DMA_FENCE_TRACE(&fence->finished,
72 "was already signaled\n");
73 }
74
drm_sched_fence_get_driver_name(struct dma_fence * fence)75 static const char *drm_sched_fence_get_driver_name(struct dma_fence *fence)
76 {
77 return "drm_sched";
78 }
79
drm_sched_fence_get_timeline_name(struct dma_fence * f)80 static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f)
81 {
82 struct drm_sched_fence *fence = to_drm_sched_fence(f);
83 return (const char *)fence->sched->name;
84 }
85
86 /**
87 * drm_sched_fence_free - free up the fence memory
88 *
89 * @rcu: RCU callback head
90 *
91 * Free up the fence memory after the RCU grace period.
92 */
drm_sched_fence_free(struct rcu_head * rcu)93 static void drm_sched_fence_free(struct rcu_head *rcu)
94 {
95 struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
96 struct drm_sched_fence *fence = to_drm_sched_fence(f);
97
98 kmem_cache_free(sched_fence_slab, fence);
99 }
100
101 /**
102 * drm_sched_fence_release_scheduled - callback that fence can be freed
103 *
104 * @f: fence
105 *
106 * This function is called when the reference count becomes zero.
107 * It just RCU schedules freeing up the fence.
108 */
drm_sched_fence_release_scheduled(struct dma_fence * f)109 static void drm_sched_fence_release_scheduled(struct dma_fence *f)
110 {
111 struct drm_sched_fence *fence = to_drm_sched_fence(f);
112
113 dma_fence_put(fence->parent);
114 call_rcu(&fence->finished.rcu, drm_sched_fence_free);
115 }
116
117 /**
118 * drm_sched_fence_release_finished - drop extra reference
119 *
120 * @f: fence
121 *
122 * Drop the extra reference from the scheduled fence to the base fence.
123 */
drm_sched_fence_release_finished(struct dma_fence * f)124 static void drm_sched_fence_release_finished(struct dma_fence *f)
125 {
126 struct drm_sched_fence *fence = to_drm_sched_fence(f);
127
128 dma_fence_put(&fence->scheduled);
129 }
130
131 static const struct dma_fence_ops drm_sched_fence_ops_scheduled = {
132 .get_driver_name = drm_sched_fence_get_driver_name,
133 .get_timeline_name = drm_sched_fence_get_timeline_name,
134 .release = drm_sched_fence_release_scheduled,
135 };
136
137 static const struct dma_fence_ops drm_sched_fence_ops_finished = {
138 .get_driver_name = drm_sched_fence_get_driver_name,
139 .get_timeline_name = drm_sched_fence_get_timeline_name,
140 .release = drm_sched_fence_release_finished,
141 };
142
to_drm_sched_fence(struct dma_fence * f)143 struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f)
144 {
145 if (f->ops == &drm_sched_fence_ops_scheduled)
146 return container_of(f, struct drm_sched_fence, scheduled);
147
148 if (f->ops == &drm_sched_fence_ops_finished)
149 return container_of(f, struct drm_sched_fence, finished);
150
151 return NULL;
152 }
153 EXPORT_SYMBOL(to_drm_sched_fence);
154
drm_sched_fence_create(struct drm_sched_entity * entity,void * owner)155 struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity,
156 void *owner)
157 {
158 struct drm_sched_fence *fence = NULL;
159 unsigned seq;
160
161 fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL);
162 if (fence == NULL)
163 return NULL;
164
165 fence->owner = owner;
166 fence->sched = entity->rq->sched;
167 spin_lock_init(&fence->lock);
168
169 seq = atomic_inc_return(&entity->fence_seq);
170 dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled,
171 &fence->lock, entity->fence_context, seq);
172 dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished,
173 &fence->lock, entity->fence_context + 1, seq);
174
175 return fence;
176 }
177
178 module_init(drm_sched_fence_slab_init);
179 module_exit(drm_sched_fence_slab_fini);
180
181 MODULE_DESCRIPTION("DRM GPU scheduler");
182 MODULE_LICENSE("GPL and additional rights");
183