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
 30static struct kmem_cache *sched_fence_slab;
 31
 32static 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
 43static void __exit drm_sched_fence_slab_fini(void)
 44{
 45	rcu_barrier();
 46	kmem_cache_destroy(sched_fence_slab);
 47}
 48
 49void 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
 61void 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
 73static const char *drm_sched_fence_get_driver_name(struct dma_fence *fence)
 74{
 75	return "drm_sched";
 76}
 77
 78static 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
 84static bool drm_sched_fence_enable_signaling(struct dma_fence *f)
 85{
 86	return true;
 87}
 88
 89/**
 90 * amd_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 */
 96static 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	dma_fence_put(fence->parent);
102	kmem_cache_free(sched_fence_slab, fence);
103}
104
105/**
106 * amd_sched_fence_release_scheduled - callback that fence can be freed
107 *
108 * @fence: fence
109 *
110 * This function is called when the reference count becomes zero.
111 * It just RCU schedules freeing up the fence.
112 */
113static void drm_sched_fence_release_scheduled(struct dma_fence *f)
114{
115	struct drm_sched_fence *fence = to_drm_sched_fence(f);
116
117	call_rcu(&fence->finished.rcu, drm_sched_fence_free);
118}
119
120/**
121 * amd_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 */
127static 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
134const 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
143const 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
152struct 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}
162EXPORT_SYMBOL(to_drm_sched_fence);
163
164struct 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
187module_init(drm_sched_fence_slab_init);
188module_exit(drm_sched_fence_slab_fini);
189
190MODULE_DESCRIPTION("DRM GPU scheduler");
191MODULE_LICENSE("GPL and additional rights");