drivers/gpu/drm/scheduler/sched_fence.c

   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         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
  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
  75 static const char *drm_sched_fence_get_driver_name(struct dma_fence *fence)
  76 {
  77         return "drm_sched";
  78 }
  79
  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  */
  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  */
 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  */
 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
 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
 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");