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 
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 
45 static void __exit drm_sched_fence_slab_fini(void)
46 {
47 	rcu_barrier();
48 	kmem_cache_destroy(sched_fence_slab);
49 }
50 
51 void drm_sched_fence_scheduled(struct drm_sched_fence *fence)
52 {
53 	dma_fence_signal(&fence->scheduled);
54 }
55 
56 void drm_sched_fence_finished(struct drm_sched_fence *fence)
57 {
58 	dma_fence_signal(&fence->finished);
59 }
60 
61 static const char *drm_sched_fence_get_driver_name(struct dma_fence *fence)
62 {
63 	return "drm_sched";
64 }
65 
66 static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f)
67 {
68 	struct drm_sched_fence *fence = to_drm_sched_fence(f);
69 	return (const char *)fence->sched->name;
70 }
71 
72 /**
73  * drm_sched_fence_free - free up the fence memory
74  *
75  * @rcu: RCU callback head
76  *
77  * Free up the fence memory after the RCU grace period.
78  */
79 void drm_sched_fence_free(struct rcu_head *rcu)
80 {
81 	struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
82 	struct drm_sched_fence *fence = to_drm_sched_fence(f);
83 
84 	kmem_cache_free(sched_fence_slab, fence);
85 }
86 
87 /**
88  * drm_sched_fence_release_scheduled - callback that fence can be freed
89  *
90  * @f: fence
91  *
92  * This function is called when the reference count becomes zero.
93  * It just RCU schedules freeing up the fence.
94  */
95 static void drm_sched_fence_release_scheduled(struct dma_fence *f)
96 {
97 	struct drm_sched_fence *fence = to_drm_sched_fence(f);
98 
99 	dma_fence_put(fence->parent);
100 	call_rcu(&fence->finished.rcu, drm_sched_fence_free);
101 }
102 
103 /**
104  * drm_sched_fence_release_finished - drop extra reference
105  *
106  * @f: fence
107  *
108  * Drop the extra reference from the scheduled fence to the base fence.
109  */
110 static void drm_sched_fence_release_finished(struct dma_fence *f)
111 {
112 	struct drm_sched_fence *fence = to_drm_sched_fence(f);
113 
114 	dma_fence_put(&fence->scheduled);
115 }
116 
117 static const struct dma_fence_ops drm_sched_fence_ops_scheduled = {
118 	.get_driver_name = drm_sched_fence_get_driver_name,
119 	.get_timeline_name = drm_sched_fence_get_timeline_name,
120 	.release = drm_sched_fence_release_scheduled,
121 };
122 
123 static const struct dma_fence_ops drm_sched_fence_ops_finished = {
124 	.get_driver_name = drm_sched_fence_get_driver_name,
125 	.get_timeline_name = drm_sched_fence_get_timeline_name,
126 	.release = drm_sched_fence_release_finished,
127 };
128 
129 struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f)
130 {
131 	if (f->ops == &drm_sched_fence_ops_scheduled)
132 		return container_of(f, struct drm_sched_fence, scheduled);
133 
134 	if (f->ops == &drm_sched_fence_ops_finished)
135 		return container_of(f, struct drm_sched_fence, finished);
136 
137 	return NULL;
138 }
139 EXPORT_SYMBOL(to_drm_sched_fence);
140 
141 struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity,
142 					      void *owner)
143 {
144 	struct drm_sched_fence *fence = NULL;
145 
146 	fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL);
147 	if (fence == NULL)
148 		return NULL;
149 
150 	fence->owner = owner;
151 	spin_lock_init(&fence->lock);
152 
153 	return fence;
154 }
155 
156 void drm_sched_fence_init(struct drm_sched_fence *fence,
157 			  struct drm_sched_entity *entity)
158 {
159 	unsigned seq;
160 
161 	fence->sched = entity->rq->sched;
162 	seq = atomic_inc_return(&entity->fence_seq);
163 	dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled,
164 		       &fence->lock, entity->fence_context, seq);
165 	dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished,
166 		       &fence->lock, entity->fence_context + 1, seq);
167 }
168 
169 module_init(drm_sched_fence_slab_init);
170 module_exit(drm_sched_fence_slab_fini);
171 
172 MODULE_DESCRIPTION("DRM GPU scheduler");
173 MODULE_LICENSE("GPL and additional rights");
174