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 static 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, s_fence->deadline); 63 } 64 65 void 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(parent)) 75 drm_sched_fence_set_parent(fence, parent); 76 77 dma_fence_signal(&fence->scheduled); 78 } 79 80 void drm_sched_fence_finished(struct drm_sched_fence *fence, int result) 81 { 82 if (result) 83 dma_fence_set_error(&fence->finished, result); 84 dma_fence_signal(&fence->finished); 85 } 86 87 static const char *drm_sched_fence_get_driver_name(struct dma_fence *fence) 88 { 89 return "drm_sched"; 90 } 91 92 static 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 98 static 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(sched_fence_slab, 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 */ 115 void 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(sched_fence_slab, 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 */ 130 static 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->parent); 135 call_rcu(&fence->finished.rcu, 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 */ 145 static 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->scheduled); 150 } 151 152 static 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(fence->deadline, deadline)) { 164 spin_unlock_irqrestore(&fence->lock, flags); 165 return; 166 } 167 168 fence->deadline = deadline; 169 set_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT, &f->flags); 170 171 spin_unlock_irqrestore(&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(parent, deadline); 181 } 182 183 static 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 }; 188 189 static 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 }; 195 196 struct 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 } 206 EXPORT_SYMBOL(to_drm_sched_fence); 207 208 struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity, 209 void *owner) 210 { 211 struct drm_sched_fence *fence = NULL; 212 213 fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL); 214 if (fence == NULL) 215 return NULL; 216 217 fence->owner = owner; 218 spin_lock_init(&fence->lock); 219 220 return fence; 221 } 222 223 void drm_sched_fence_init(struct drm_sched_fence *fence, 224 struct drm_sched_entity *entity) 225 { 226 unsigned seq; 227 228 fence->sched = entity->rq->sched; 229 seq = atomic_inc_return(&entity->fence_seq); 230 dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled, 231 &fence->lock, entity->fence_context, seq); 232 dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished, 233 &fence->lock, entity->fence_context + 1, seq); 234 } 235 236 module_init(drm_sched_fence_slab_init); 237 module_exit(drm_sched_fence_slab_fini); 238 239 MODULE_DESCRIPTION("DRM GPU scheduler"); 240 MODULE_LICENSE("GPL and additional rights"); 241