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 "gpu_scheduler.h"
 29
 30static struct kmem_cache *sched_fence_slab;
 31
 32int amd_sched_fence_slab_init(void)
 33{
 34	sched_fence_slab = kmem_cache_create(
 35		"amd_sched_fence", sizeof(struct amd_sched_fence), 0,
 36		SLAB_HWCACHE_ALIGN, NULL);
 37	if (!sched_fence_slab)
 38		return -ENOMEM;
 39
 40	return 0;
 41}
 42
 43void amd_sched_fence_slab_fini(void)
 44{
 45	rcu_barrier();
 46	kmem_cache_destroy(sched_fence_slab);
 47}
 48
 49struct amd_sched_fence *amd_sched_fence_create(struct amd_sched_entity *entity,
 50					       void *owner)
 51{
 52	struct amd_sched_fence *fence = NULL;
 53	unsigned seq;
 54
 55	fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL);
 56	if (fence == NULL)
 57		return NULL;
 58
 59	fence->owner = owner;
 60	fence->sched = entity->sched;
 61	spin_lock_init(&fence->lock);
 62
 63	seq = atomic_inc_return(&entity->fence_seq);
 64	dma_fence_init(&fence->scheduled, &amd_sched_fence_ops_scheduled,
 65		       &fence->lock, entity->fence_context, seq);
 66	dma_fence_init(&fence->finished, &amd_sched_fence_ops_finished,
 67		       &fence->lock, entity->fence_context + 1, seq);
 68
 69	return fence;
 70}
 71
 72void amd_sched_fence_scheduled(struct amd_sched_fence *fence)
 73{
 74	int ret = dma_fence_signal(&fence->scheduled);
 75
 76	if (!ret)
 77		DMA_FENCE_TRACE(&fence->scheduled,
 78				"signaled from irq context\n");
 79	else
 80		DMA_FENCE_TRACE(&fence->scheduled,
 81				"was already signaled\n");
 82}
 83
 84void amd_sched_fence_finished(struct amd_sched_fence *fence)
 85{
 86	int ret = dma_fence_signal(&fence->finished);
 87
 88	if (!ret)
 89		DMA_FENCE_TRACE(&fence->finished,
 90				"signaled from irq context\n");
 91	else
 92		DMA_FENCE_TRACE(&fence->finished,
 93				"was already signaled\n");
 94}
 95
 96static const char *amd_sched_fence_get_driver_name(struct dma_fence *fence)
 97{
 98	return "amd_sched";
 99}
100
101static const char *amd_sched_fence_get_timeline_name(struct dma_fence *f)
102{
103	struct amd_sched_fence *fence = to_amd_sched_fence(f);
104	return (const char *)fence->sched->name;
105}
106
107static bool amd_sched_fence_enable_signaling(struct dma_fence *f)
108{
109	return true;
110}
111
112/**
113 * amd_sched_fence_free - free up the fence memory
114 *
115 * @rcu: RCU callback head
116 *
117 * Free up the fence memory after the RCU grace period.
118 */
119static void amd_sched_fence_free(struct rcu_head *rcu)
120{
121	struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
122	struct amd_sched_fence *fence = to_amd_sched_fence(f);
123
124	dma_fence_put(fence->parent);
125	kmem_cache_free(sched_fence_slab, fence);
126}
127
128/**
129 * amd_sched_fence_release_scheduled - callback that fence can be freed
130 *
131 * @fence: fence
132 *
133 * This function is called when the reference count becomes zero.
134 * It just RCU schedules freeing up the fence.
135 */
136static void amd_sched_fence_release_scheduled(struct dma_fence *f)
137{
138	struct amd_sched_fence *fence = to_amd_sched_fence(f);
139
140	call_rcu(&fence->finished.rcu, amd_sched_fence_free);
141}
142
143/**
144 * amd_sched_fence_release_finished - drop extra reference
145 *
146 * @f: fence
147 *
148 * Drop the extra reference from the scheduled fence to the base fence.
149 */
150static void amd_sched_fence_release_finished(struct dma_fence *f)
151{
152	struct amd_sched_fence *fence = to_amd_sched_fence(f);
153
154	dma_fence_put(&fence->scheduled);
155}
156
157const struct dma_fence_ops amd_sched_fence_ops_scheduled = {
158	.get_driver_name = amd_sched_fence_get_driver_name,
159	.get_timeline_name = amd_sched_fence_get_timeline_name,
160	.enable_signaling = amd_sched_fence_enable_signaling,
161	.signaled = NULL,
162	.wait = dma_fence_default_wait,
163	.release = amd_sched_fence_release_scheduled,
164};
165
166const struct dma_fence_ops amd_sched_fence_ops_finished = {
167	.get_driver_name = amd_sched_fence_get_driver_name,
168	.get_timeline_name = amd_sched_fence_get_timeline_name,
169	.enable_signaling = amd_sched_fence_enable_signaling,
170	.signaled = NULL,
171	.wait = dma_fence_default_wait,
172	.release = amd_sched_fence_release_finished,
173};