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