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/wait.h>
  26 #include <linux/sched.h>
  27 #include <drm/drmP.h>
  28 #include <drm/gpu_scheduler.h>
  29
  30 static struct kmem_cache *sched_fence_slab;
  31
  32 static int __init drm_sched_fence_slab_init(void)
  33 {
  34         sched_fence_slab = kmem_cache_create(
  35                 "drm_sched_fence", sizeof(struct drm_sched_fence), 0,
  36                 SLAB_HWCACHE_ALIGN, NULL);
  37         if (!sched_fence_slab)
  38                 return -ENOMEM;
  39
  40         return 0;
  41 }
  42
  43 static void __exit drm_sched_fence_slab_fini(void)
  44 {
  45         rcu_barrier();
  46         kmem_cache_destroy(sched_fence_slab);
  47 }
  48
  49 void drm_sched_fence_scheduled(struct drm_sched_fence *fence)
  50 {
  51         int ret = dma_fence_signal(&fence->scheduled);
  52
  53         if (!ret)
  54                 DMA_FENCE_TRACE(&fence->scheduled,
  55                                 "signaled from irq context\n");
  56         else
  57                 DMA_FENCE_TRACE(&fence->scheduled,
  58                                 "was already signaled\n");
  59 }
  60
  61 void drm_sched_fence_finished(struct drm_sched_fence *fence)
  62 {
  63         int ret = dma_fence_signal(&fence->finished);
  64
  65         if (!ret)
  66                 DMA_FENCE_TRACE(&fence->finished,
  67                                 "signaled from irq context\n");
  68         else
  69                 DMA_FENCE_TRACE(&fence->finished,
  70                                 "was already signaled\n");
  71 }
  72
  73 static const char *drm_sched_fence_get_driver_name(struct dma_fence *fence)
  74 {
  75         return "drm_sched";
  76 }
  77
  78 static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f)
  79 {
  80         struct drm_sched_fence *fence = to_drm_sched_fence(f);
  81         return (const char *)fence->sched->name;
  82 }
  83
  84 static bool drm_sched_fence_enable_signaling(struct dma_fence *f)
  85 {
  86         return true;
  87 }
  88
  89 /**
  90  * drm_sched_fence_free - free up the fence memory
  91  *
  92  * @rcu: RCU callback head
  93  *
  94  * Free up the fence memory after the RCU grace period.
  95  */
  96 static void drm_sched_fence_free(struct rcu_head *rcu)
  97 {
  98         struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
  99         struct drm_sched_fence *fence = to_drm_sched_fence(f);
 100
 101         kmem_cache_free(sched_fence_slab, fence);
 102 }
 103
 104 /**
 105  * drm_sched_fence_release_scheduled - callback that fence can be freed
 106  *
 107  * @fence: fence
 108  *
 109  * This function is called when the reference count becomes zero.
 110  * It just RCU schedules freeing up the fence.
 111  */
 112 static void drm_sched_fence_release_scheduled(struct dma_fence *f)
 113 {
 114         struct drm_sched_fence *fence = to_drm_sched_fence(f);
 115
 116         dma_fence_put(fence->parent);
 117         call_rcu(&fence->finished.rcu, drm_sched_fence_free);
 118 }
 119
 120 /**
 121  * drm_sched_fence_release_finished - drop extra reference
 122  *
 123  * @f: fence
 124  *
 125  * Drop the extra reference from the scheduled fence to the base fence.
 126  */
 127 static void drm_sched_fence_release_finished(struct dma_fence *f)
 128 {
 129         struct drm_sched_fence *fence = to_drm_sched_fence(f);
 130
 131         dma_fence_put(&fence->scheduled);
 132 }
 133
 134 const struct dma_fence_ops drm_sched_fence_ops_scheduled = {
 135         .get_driver_name = drm_sched_fence_get_driver_name,
 136         .get_timeline_name = drm_sched_fence_get_timeline_name,
 137         .enable_signaling = drm_sched_fence_enable_signaling,
 138         .signaled = NULL,
 139         .wait = dma_fence_default_wait,
 140         .release = drm_sched_fence_release_scheduled,
 141 };
 142
 143 const struct dma_fence_ops drm_sched_fence_ops_finished = {
 144         .get_driver_name = drm_sched_fence_get_driver_name,
 145         .get_timeline_name = drm_sched_fence_get_timeline_name,
 146         .enable_signaling = drm_sched_fence_enable_signaling,
 147         .signaled = NULL,
 148         .wait = dma_fence_default_wait,
 149         .release = drm_sched_fence_release_finished,
 150 };
 151
 152 struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f)
 153 {
 154         if (f->ops == &drm_sched_fence_ops_scheduled)
 155                 return container_of(f, struct drm_sched_fence, scheduled);
 156
 157         if (f->ops == &drm_sched_fence_ops_finished)
 158                 return container_of(f, struct drm_sched_fence, finished);
 159
 160         return NULL;
 161 }
 162 EXPORT_SYMBOL(to_drm_sched_fence);
 163
 164 struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity,
 165                                                void *owner)
 166 {
 167         struct drm_sched_fence *fence = NULL;
 168         unsigned seq;
 169
 170         fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL);
 171         if (fence == NULL)
 172                 return NULL;
 173
 174         fence->owner = owner;
 175         fence->sched = entity->sched;
 176         spin_lock_init(&fence->lock);
 177
 178         seq = atomic_inc_return(&entity->fence_seq);
 179         dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled,
 180                        &fence->lock, entity->fence_context, seq);
 181         dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished,
 182                        &fence->lock, entity->fence_context + 1, seq);
 183
 184         return fence;
 185 }
 186
 187 module_init(drm_sched_fence_slab_init);
 188 module_exit(drm_sched_fence_slab_fini);
 189
 190 MODULE_DESCRIPTION("DRM GPU scheduler");
 191 MODULE_LICENSE("GPL and additional rights");