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
 32static struct kmem_cache *sched_fence_slab;
 33
 34static 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
 45static void __exit drm_sched_fence_slab_fini(void)
 46{
 47	rcu_barrier();
 48	kmem_cache_destroy(sched_fence_slab);
 49}
 50
 51void 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
 63void 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
 75static const char *drm_sched_fence_get_driver_name(struct dma_fence *fence)
 76{
 77	return "drm_sched";
 78}
 79
 80static 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 */
 93static 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 * @fence: fence
105 *
106 * This function is called when the reference count becomes zero.
107 * It just RCU schedules freeing up the fence.
108 */
109static 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 */
124static 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
131static 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
137static 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
143struct 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}
153EXPORT_SYMBOL(to_drm_sched_fence);
154
155struct 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
178module_init(drm_sched_fence_slab_init);
179module_exit(drm_sched_fence_slab_fini);
180
181MODULE_DESCRIPTION("DRM GPU scheduler");
182MODULE_LICENSE("GPL and additional rights");