1 files changed, 240 insertions, 0 deletions
diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c
new file mode 100644
index 000000000..06cedfe4b
--- /dev/null
+++ b/drivers/gpu/drm/scheduler/sched_fence.c
@@ -0,0 +1,240 @@
+/*
+ * Copyright 2015 Advanced Micro Devices, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+
+#include <drm/gpu_scheduler.h>
+
+static struct kmem_cache *sched_fence_slab;
+
+static int __init drm_sched_fence_slab_init(void)
+{
+	sched_fence_slab = kmem_cache_create(
+		"drm_sched_fence", sizeof(struct drm_sched_fence), 0,
+		SLAB_HWCACHE_ALIGN, NULL);
+	if (!sched_fence_slab)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void __exit drm_sched_fence_slab_fini(void)
+{
+	rcu_barrier();
+	kmem_cache_destroy(sched_fence_slab);
+}
+
+static void drm_sched_fence_set_parent(struct drm_sched_fence *s_fence,
+				       struct dma_fence *fence)
+{
+	/*
+	 * smp_store_release() to ensure another thread racing us
+	 * in drm_sched_fence_set_deadline_finished() sees the
+	 * fence's parent set before test_bit()
+	 */
+	smp_store_release(&s_fence->parent, dma_fence_get(fence));
+	if (test_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT,
+		     &s_fence->finished.flags))
+		dma_fence_set_deadline(fence, s_fence->deadline);
+}
+
+void drm_sched_fence_scheduled(struct drm_sched_fence *fence,
+			       struct dma_fence *parent)
+{
+	/* Set the parent before signaling the scheduled fence, such that,
+	 * any waiter expecting the parent to be filled after the job has
+	 * been scheduled (which is the case for drivers delegating waits
+	 * to some firmware) doesn't have to busy wait for parent to show
+	 * up.
+	 */
+	if (!IS_ERR_OR_NULL(parent))
+		drm_sched_fence_set_parent(fence, parent);
+
+	dma_fence_signal(&fence->scheduled);
+}
+
+void drm_sched_fence_finished(struct drm_sched_fence *fence, int result)
+{
+	if (result)
+		dma_fence_set_error(&fence->finished, result);
+	dma_fence_signal(&fence->finished);
+}
+
+static const char *drm_sched_fence_get_driver_name(struct dma_fence *fence)
+{
+	return "drm_sched";
+}
+
+static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f)
+{
+	struct drm_sched_fence *fence = to_drm_sched_fence(f);
+	return (const char *)fence->sched->name;
+}
+
+static void drm_sched_fence_free_rcu(struct rcu_head *rcu)
+{
+	struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
+	struct drm_sched_fence *fence = to_drm_sched_fence(f);
+
+	if (!WARN_ON_ONCE(!fence))
+		kmem_cache_free(sched_fence_slab, fence);
+}
+
+/**
+ * drm_sched_fence_free - free up an uninitialized fence
+ *
+ * @fence: fence to free
+ *
+ * Free up the fence memory. Should only be used if drm_sched_fence_init()
+ * has not been called yet.
+ */
+void drm_sched_fence_free(struct drm_sched_fence *fence)
+{
+	/* This function should not be called if the fence has been initialized. */
+	if (!WARN_ON_ONCE(fence->sched))
+		kmem_cache_free(sched_fence_slab, fence);
+}
+
+/**
+ * drm_sched_fence_release_scheduled - callback that fence can be freed
+ *
+ * @f: fence
+ *
+ * This function is called when the reference count becomes zero.
+ * It just RCU schedules freeing up the fence.
+ */
+static void drm_sched_fence_release_scheduled(struct dma_fence *f)
+{
+	struct drm_sched_fence *fence = to_drm_sched_fence(f);
+
+	dma_fence_put(fence->parent);
+	call_rcu(&fence->finished.rcu, drm_sched_fence_free_rcu);
+}
+
+/**
+ * drm_sched_fence_release_finished - drop extra reference
+ *
+ * @f: fence
+ *
+ * Drop the extra reference from the scheduled fence to the base fence.
+ */
+static void drm_sched_fence_release_finished(struct dma_fence *f)
+{
+	struct drm_sched_fence *fence = to_drm_sched_fence(f);
+
+	dma_fence_put(&fence->scheduled);
+}
+
+static void drm_sched_fence_set_deadline_finished(struct dma_fence *f,
+						  ktime_t deadline)
+{
+	struct drm_sched_fence *fence = to_drm_sched_fence(f);
+	struct dma_fence *parent;
+	unsigned long flags;
+
+	spin_lock_irqsave(&fence->lock, flags);
+
+	/* If we already have an earlier deadline, keep it: */
+	if (test_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT, &f->flags) &&
+	    ktime_before(fence->deadline, deadline)) {
+		spin_unlock_irqrestore(&fence->lock, flags);
+		return;
+	}
+
+	fence->deadline = deadline;
+	set_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT, &f->flags);
+
+	spin_unlock_irqrestore(&fence->lock, flags);
+
+	/*
+	 * smp_load_aquire() to ensure that if we are racing another
+	 * thread calling drm_sched_fence_set_parent(), that we see
+	 * the parent set before it calls test_bit(HAS_DEADLINE_BIT)
+	 */
+	parent = smp_load_acquire(&fence->parent);
+	if (parent)
+		dma_fence_set_deadline(parent, deadline);
+}
+
+static const struct dma_fence_ops drm_sched_fence_ops_scheduled = {
+	.get_driver_name = drm_sched_fence_get_driver_name,
+	.get_timeline_name = drm_sched_fence_get_timeline_name,
+	.release = drm_sched_fence_release_scheduled,
+};
+
+static const struct dma_fence_ops drm_sched_fence_ops_finished = {
+	.get_driver_name = drm_sched_fence_get_driver_name,
+	.get_timeline_name = drm_sched_fence_get_timeline_name,
+	.release = drm_sched_fence_release_finished,
+	.set_deadline = drm_sched_fence_set_deadline_finished,
+};
+
+struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f)
+{
+	if (f->ops == &drm_sched_fence_ops_scheduled)
+		return container_of(f, struct drm_sched_fence, scheduled);
+
+	if (f->ops == &drm_sched_fence_ops_finished)
+		return container_of(f, struct drm_sched_fence, finished);
+
+	return NULL;
+}
+EXPORT_SYMBOL(to_drm_sched_fence);
+
+struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity,
+					      void *owner)
+{
+	struct drm_sched_fence *fence = NULL;
+
+	fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL);
+	if (fence == NULL)
+		return NULL;
+
+	fence->owner = owner;
+	spin_lock_init(&fence->lock);
+
+	return fence;
+}
+
+void drm_sched_fence_init(struct drm_sched_fence *fence,
+			  struct drm_sched_entity *entity)
+{
+	unsigned seq;
+
+	fence->sched = entity->rq->sched;
+	seq = atomic_inc_return(&entity->fence_seq);
+	dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled,
+		       &fence->lock, entity->fence_context, seq);
+	dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished,
+		       &fence->lock, entity->fence_context + 1, seq);
+}
+
+module_init(drm_sched_fence_slab_init);
+module_exit(drm_sched_fence_slab_fini);
+
+MODULE_DESCRIPTION("DRM GPU scheduler");
+MODULE_LICENSE("GPL and additional rights");