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 static void drm_sched_fence_free_rcu(struct rcu_head *rcu) 73 { 74 struct dma_fence *f = container_of(rcu, struct dma_fence, rcu); 75 struct drm_sched_fence *fence = to_drm_sched_fence(f); 76 77 if (!WARN_ON_ONCE(!fence)) 78 kmem_cache_free(sched_fence_slab, fence); 79 } 80 81 /** 82 * drm_sched_fence_free - free up an uninitialized fence 83 * 84 * @fence: fence to free 85 * 86 * Free up the fence memory. Should only be used if drm_sched_fence_init() 87 * has not been called yet. 88 */ 89 void drm_sched_fence_free(struct drm_sched_fence *fence) 90 { 91 /* This function should not be called if the fence has been initialized. */ 92 if (!WARN_ON_ONCE(fence->sched)) 93 kmem_cache_free(sched_fence_slab, fence); 94 } 95 96 /** 97 * drm_sched_fence_release_scheduled - callback that fence can be freed 98 * 99 * @f: fence 100 * 101 * This function is called when the reference count becomes zero. 102 * It just RCU schedules freeing up the fence. 103 */ 104 static void drm_sched_fence_release_scheduled(struct dma_fence *f) 105 { 106 struct drm_sched_fence *fence = to_drm_sched_fence(f); 107 108 dma_fence_put(fence->parent); 109 call_rcu(&fence->finished.rcu, drm_sched_fence_free_rcu); 110 } 111 112 /** 113 * drm_sched_fence_release_finished - drop extra reference 114 * 115 * @f: fence 116 * 117 * Drop the extra reference from the scheduled fence to the base fence. 118 */ 119 static void drm_sched_fence_release_finished(struct dma_fence *f) 120 { 121 struct drm_sched_fence *fence = to_drm_sched_fence(f); 122 123 dma_fence_put(&fence->scheduled); 124 } 125 126 static void drm_sched_fence_set_deadline_finished(struct dma_fence *f, 127 ktime_t deadline) 128 { 129 struct drm_sched_fence *fence = to_drm_sched_fence(f); 130 struct dma_fence *parent; 131 unsigned long flags; 132 133 spin_lock_irqsave(&fence->lock, flags); 134 135 /* If we already have an earlier deadline, keep it: */ 136 if (test_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT, &f->flags) && 137 ktime_before(fence->deadline, deadline)) { 138 spin_unlock_irqrestore(&fence->lock, flags); 139 return; 140 } 141 142 fence->deadline = deadline; 143 set_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT, &f->flags); 144 145 spin_unlock_irqrestore(&fence->lock, flags); 146 147 /* 148 * smp_load_aquire() to ensure that if we are racing another 149 * thread calling drm_sched_fence_set_parent(), that we see 150 * the parent set before it calls test_bit(HAS_DEADLINE_BIT) 151 */ 152 parent = smp_load_acquire(&fence->parent); 153 if (parent) 154 dma_fence_set_deadline(parent, deadline); 155 } 156 157 static const struct dma_fence_ops drm_sched_fence_ops_scheduled = { 158 .get_driver_name = drm_sched_fence_get_driver_name, 159 .get_timeline_name = drm_sched_fence_get_timeline_name, 160 .release = drm_sched_fence_release_scheduled, 161 }; 162 163 static const struct dma_fence_ops drm_sched_fence_ops_finished = { 164 .get_driver_name = drm_sched_fence_get_driver_name, 165 .get_timeline_name = drm_sched_fence_get_timeline_name, 166 .release = drm_sched_fence_release_finished, 167 .set_deadline = drm_sched_fence_set_deadline_finished, 168 }; 169 170 struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f) 171 { 172 if (f->ops == &drm_sched_fence_ops_scheduled) 173 return container_of(f, struct drm_sched_fence, scheduled); 174 175 if (f->ops == &drm_sched_fence_ops_finished) 176 return container_of(f, struct drm_sched_fence, finished); 177 178 return NULL; 179 } 180 EXPORT_SYMBOL(to_drm_sched_fence); 181 182 void drm_sched_fence_set_parent(struct drm_sched_fence *s_fence, 183 struct dma_fence *fence) 184 { 185 /* 186 * smp_store_release() to ensure another thread racing us 187 * in drm_sched_fence_set_deadline_finished() sees the 188 * fence's parent set before test_bit() 189 */ 190 smp_store_release(&s_fence->parent, dma_fence_get(fence)); 191 if (test_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT, 192 &s_fence->finished.flags)) 193 dma_fence_set_deadline(fence, s_fence->deadline); 194 } 195 196 struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity, 197 void *owner) 198 { 199 struct drm_sched_fence *fence = NULL; 200 201 fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL); 202 if (fence == NULL) 203 return NULL; 204 205 fence->owner = owner; 206 spin_lock_init(&fence->lock); 207 208 return fence; 209 } 210 211 void drm_sched_fence_init(struct drm_sched_fence *fence, 212 struct drm_sched_entity *entity) 213 { 214 unsigned seq; 215 216 fence->sched = entity->rq->sched; 217 seq = atomic_inc_return(&entity->fence_seq); 218 dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled, 219 &fence->lock, entity->fence_context, seq); 220 dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished, 221 &fence->lock, entity->fence_context + 1, seq); 222 } 223 224 module_init(drm_sched_fence_slab_init); 225 module_exit(drm_sched_fence_slab_fini); 226 227 MODULE_DESCRIPTION("DRM GPU scheduler"); 228 MODULE_LICENSE("GPL and additional rights"); 229