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/export.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#include "sched_internal.h"
33
34static struct kmem_cache *sched_fence_slab;
35
36static int __init drm_sched_fence_slab_init(void)
37{
38 sched_fence_slab = KMEM_CACHE(drm_sched_fence, SLAB_HWCACHE_ALIGN);
39 if (!sched_fence_slab)
40 return -ENOMEM;
41
42 return 0;
43}
44
45static void __exit drm_sched_fence_slab_fini(void)
46{
47 rcu_barrier();
48 kmem_cache_destroy(s: sched_fence_slab);
49}
50
51static void drm_sched_fence_set_parent(struct drm_sched_fence *s_fence,
52 struct dma_fence *fence)
53{
54 /*
55 * smp_store_release() to ensure another thread racing us
56 * in drm_sched_fence_set_deadline_finished() sees the
57 * fence's parent set before test_bit()
58 */
59 smp_store_release(&s_fence->parent, dma_fence_get(fence));
60 if (test_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT,
61 &s_fence->finished.flags))
62 dma_fence_set_deadline(fence, deadline: s_fence->deadline);
63}
64
65void drm_sched_fence_scheduled(struct drm_sched_fence *fence,
66 struct dma_fence *parent)
67{
68 /* Set the parent before signaling the scheduled fence, such that,
69 * any waiter expecting the parent to be filled after the job has
70 * been scheduled (which is the case for drivers delegating waits
71 * to some firmware) doesn't have to busy wait for parent to show
72 * up.
73 */
74 if (!IS_ERR_OR_NULL(ptr: parent))
75 drm_sched_fence_set_parent(s_fence: fence, fence: parent);
76
77 dma_fence_signal(fence: &fence->scheduled);
78}
79
80void drm_sched_fence_finished(struct drm_sched_fence *fence, int result)
81{
82 if (result)
83 dma_fence_set_error(fence: &fence->finished, error: result);
84 dma_fence_signal(fence: &fence->finished);
85}
86
87static const char *drm_sched_fence_get_driver_name(struct dma_fence *fence)
88{
89 return "drm_sched";
90}
91
92static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f)
93{
94 struct drm_sched_fence *fence = to_drm_sched_fence(f);
95 return (const char *)fence->sched->name;
96}
97
98static void drm_sched_fence_free_rcu(struct rcu_head *rcu)
99{
100 struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
101 struct drm_sched_fence *fence = to_drm_sched_fence(f);
102
103 if (!WARN_ON_ONCE(!fence))
104 kmem_cache_free(s: sched_fence_slab, objp: fence);
105}
106
107/**
108 * drm_sched_fence_free - free up an uninitialized fence
109 *
110 * @fence: fence to free
111 *
112 * Free up the fence memory. Should only be used if drm_sched_fence_init()
113 * has not been called yet.
114 */
115void drm_sched_fence_free(struct drm_sched_fence *fence)
116{
117 /* This function should not be called if the fence has been initialized. */
118 if (!WARN_ON_ONCE(fence->sched))
119 kmem_cache_free(s: sched_fence_slab, objp: fence);
120}
121
122/**
123 * drm_sched_fence_release_scheduled - callback that fence can be freed
124 *
125 * @f: fence
126 *
127 * This function is called when the reference count becomes zero.
128 * It just RCU schedules freeing up the fence.
129 */
130static void drm_sched_fence_release_scheduled(struct dma_fence *f)
131{
132 struct drm_sched_fence *fence = to_drm_sched_fence(f);
133
134 dma_fence_put(fence: fence->parent);
135 call_rcu(head: &fence->finished.rcu, func: drm_sched_fence_free_rcu);
136}
137
138/**
139 * drm_sched_fence_release_finished - drop extra reference
140 *
141 * @f: fence
142 *
143 * Drop the extra reference from the scheduled fence to the base fence.
144 */
145static void drm_sched_fence_release_finished(struct dma_fence *f)
146{
147 struct drm_sched_fence *fence = to_drm_sched_fence(f);
148
149 dma_fence_put(fence: &fence->scheduled);
150}
151
152static void drm_sched_fence_set_deadline_finished(struct dma_fence *f,
153 ktime_t deadline)
154{
155 struct drm_sched_fence *fence = to_drm_sched_fence(f);
156 struct dma_fence *parent;
157 unsigned long flags;
158
159 spin_lock_irqsave(&fence->lock, flags);
160
161 /* If we already have an earlier deadline, keep it: */
162 if (test_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT, &f->flags) &&
163 ktime_before(cmp1: fence->deadline, cmp2: deadline)) {
164 spin_unlock_irqrestore(lock: &fence->lock, flags);
165 return;
166 }
167
168 fence->deadline = deadline;
169 set_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT, addr: &f->flags);
170
171 spin_unlock_irqrestore(lock: &fence->lock, flags);
172
173 /*
174 * smp_load_aquire() to ensure that if we are racing another
175 * thread calling drm_sched_fence_set_parent(), that we see
176 * the parent set before it calls test_bit(HAS_DEADLINE_BIT)
177 */
178 parent = smp_load_acquire(&fence->parent);
179 if (parent)
180 dma_fence_set_deadline(fence: parent, deadline);
181}
182
183static const struct dma_fence_ops drm_sched_fence_ops_scheduled = {
184 .get_driver_name = drm_sched_fence_get_driver_name,
185 .get_timeline_name = drm_sched_fence_get_timeline_name,
186 .release = drm_sched_fence_release_scheduled,
187};
188
189static const struct dma_fence_ops drm_sched_fence_ops_finished = {
190 .get_driver_name = drm_sched_fence_get_driver_name,
191 .get_timeline_name = drm_sched_fence_get_timeline_name,
192 .release = drm_sched_fence_release_finished,
193 .set_deadline = drm_sched_fence_set_deadline_finished,
194};
195
196struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f)
197{
198 if (f->ops == &drm_sched_fence_ops_scheduled)
199 return container_of(f, struct drm_sched_fence, scheduled);
200
201 if (f->ops == &drm_sched_fence_ops_finished)
202 return container_of(f, struct drm_sched_fence, finished);
203
204 return NULL;
205}
206EXPORT_SYMBOL(to_drm_sched_fence);
207
208struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity,
209 void *owner,
210 u64 drm_client_id)
211{
212 struct drm_sched_fence *fence = NULL;
213
214 fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL);
215 if (fence == NULL)
216 return NULL;
217
218 fence->owner = owner;
219 fence->drm_client_id = drm_client_id;
220 spin_lock_init(&fence->lock);
221
222 return fence;
223}
224
225void drm_sched_fence_init(struct drm_sched_fence *fence,
226 struct drm_sched_entity *entity)
227{
228 unsigned seq;
229
230 fence->sched = entity->rq->sched;
231 seq = atomic_inc_return(v: &entity->fence_seq);
232 dma_fence_init(fence: &fence->scheduled, ops: &drm_sched_fence_ops_scheduled,
233 lock: &fence->lock, context: entity->fence_context, seqno: seq);
234 dma_fence_init(fence: &fence->finished, ops: &drm_sched_fence_ops_finished,
235 lock: &fence->lock, context: entity->fence_context + 1, seqno: seq);
236}
237
238module_init(drm_sched_fence_slab_init);
239module_exit(drm_sched_fence_slab_fini);
240
241MODULE_DESCRIPTION("DRM GPU scheduler");
242MODULE_LICENSE("GPL and additional rights");
243

source code of linux/drivers/gpu/drm/scheduler/sched_fence.c