Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1127 insertions, 0 deletions

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
new file mode 100644
index 000000000..f138b3be1
--- /dev/null
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -0,0 +1,1127 @@
+/*
+ * 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.
+ *
+ */
+
+/**
+ * DOC: Overview
+ *
+ * The GPU scheduler provides entities which allow userspace to push jobs
+ * into software queues which are then scheduled on a hardware run queue.
+ * The software queues have a priority among them. The scheduler selects the entities
+ * from the run queue using a FIFO. The scheduler provides dependency handling
+ * features among jobs. The driver is supposed to provide callback functions for
+ * backend operations to the scheduler like submitting a job to hardware run queue,
+ * returning the dependencies of a job etc.
+ *
+ * The organisation of the scheduler is the following:
+ *
+ * 1. Each hw run queue has one scheduler
+ * 2. Each scheduler has multiple run queues with different priorities
+ *    (e.g., HIGH_HW,HIGH_SW, KERNEL, NORMAL)
+ * 3. Each scheduler run queue has a queue of entities to schedule
+ * 4. Entities themselves maintain a queue of jobs that will be scheduled on
+ *    the hardware.
+ *
+ * The jobs in a entity are always scheduled in the order that they were pushed.
+ */
+
+#include <linux/kthread.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/dma-resv.h>
+#include <uapi/linux/sched/types.h>
+
+#include <drm/drm_print.h>
+#include <drm/drm_gem.h>
+#include <drm/gpu_scheduler.h>
+#include <drm/spsc_queue.h>
+
+#define CREATE_TRACE_POINTS
+#include "gpu_scheduler_trace.h"
+
+#define to_drm_sched_job(sched_job)		\
+		container_of((sched_job), struct drm_sched_job, queue_node)
+
+/**
+ * drm_sched_rq_init - initialize a given run queue struct
+ *
+ * @sched: scheduler instance to associate with this run queue
+ * @rq: scheduler run queue
+ *
+ * Initializes a scheduler runqueue.
+ */
+static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
+			      struct drm_sched_rq *rq)
+{
+	spin_lock_init(&rq->lock);
+	INIT_LIST_HEAD(&rq->entities);
+	rq->current_entity = NULL;
+	rq->sched = sched;
+}
+
+/**
+ * drm_sched_rq_add_entity - add an entity
+ *
+ * @rq: scheduler run queue
+ * @entity: scheduler entity
+ *
+ * Adds a scheduler entity to the run queue.
+ */
+void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
+			     struct drm_sched_entity *entity)
+{
+	if (!list_empty(&entity->list))
+		return;
+	spin_lock(&rq->lock);
+	atomic_inc(rq->sched->score);
+	list_add_tail(&entity->list, &rq->entities);
+	spin_unlock(&rq->lock);
+}
+
+/**
+ * drm_sched_rq_remove_entity - remove an entity
+ *
+ * @rq: scheduler run queue
+ * @entity: scheduler entity
+ *
+ * Removes a scheduler entity from the run queue.
+ */
+void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
+				struct drm_sched_entity *entity)
+{
+	if (list_empty(&entity->list))
+		return;
+	spin_lock(&rq->lock);
+	atomic_dec(rq->sched->score);
+	list_del_init(&entity->list);
+	if (rq->current_entity == entity)
+		rq->current_entity = NULL;
+	spin_unlock(&rq->lock);
+}
+
+/**
+ * drm_sched_rq_select_entity - Select an entity which could provide a job to run
+ *
+ * @rq: scheduler run queue to check.
+ *
+ * Try to find a ready entity, returns NULL if none found.
+ */
+static struct drm_sched_entity *
+drm_sched_rq_select_entity(struct drm_sched_rq *rq)
+{
+	struct drm_sched_entity *entity;
+
+	spin_lock(&rq->lock);
+
+	entity = rq->current_entity;
+	if (entity) {
+		list_for_each_entry_continue(entity, &rq->entities, list) {
+			if (drm_sched_entity_is_ready(entity)) {
+				rq->current_entity = entity;
+				reinit_completion(&entity->entity_idle);
+				spin_unlock(&rq->lock);
+				return entity;
+			}
+		}
+	}
+
+	list_for_each_entry(entity, &rq->entities, list) {
+
+		if (drm_sched_entity_is_ready(entity)) {
+			rq->current_entity = entity;
+			reinit_completion(&entity->entity_idle);
+			spin_unlock(&rq->lock);
+			return entity;
+		}
+
+		if (entity == rq->current_entity)
+			break;
+	}
+
+	spin_unlock(&rq->lock);
+
+	return NULL;
+}
+
+/**
+ * drm_sched_job_done - complete a job
+ * @s_job: pointer to the job which is done
+ *
+ * Finish the job's fence and wake up the worker thread.
+ */
+static void drm_sched_job_done(struct drm_sched_job *s_job)
+{
+	struct drm_sched_fence *s_fence = s_job->s_fence;
+	struct drm_gpu_scheduler *sched = s_fence->sched;
+
+	atomic_dec(&sched->hw_rq_count);
+	atomic_dec(sched->score);
+
+	trace_drm_sched_process_job(s_fence);
+
+	dma_fence_get(&s_fence->finished);
+	drm_sched_fence_finished(s_fence);
+	dma_fence_put(&s_fence->finished);
+	wake_up_interruptible(&sched->wake_up_worker);
+}
+
+/**
+ * drm_sched_job_done_cb - the callback for a done job
+ * @f: fence
+ * @cb: fence callbacks
+ */
+static void drm_sched_job_done_cb(struct dma_fence *f, struct dma_fence_cb *cb)
+{
+	struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb);
+
+	drm_sched_job_done(s_job);
+}
+
+/**
+ * drm_sched_dependency_optimized - test if the dependency can be optimized
+ *
+ * @fence: the dependency fence
+ * @entity: the entity which depends on the above fence
+ *
+ * Returns true if the dependency can be optimized and false otherwise
+ */
+bool drm_sched_dependency_optimized(struct dma_fence* fence,
+				    struct drm_sched_entity *entity)
+{
+	struct drm_gpu_scheduler *sched = entity->rq->sched;
+	struct drm_sched_fence *s_fence;
+
+	if (!fence || dma_fence_is_signaled(fence))
+		return false;
+	if (fence->context == entity->fence_context)
+		return true;
+	s_fence = to_drm_sched_fence(fence);
+	if (s_fence && s_fence->sched == sched)
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL(drm_sched_dependency_optimized);
+
+/**
+ * drm_sched_start_timeout - start timeout for reset worker
+ *
+ * @sched: scheduler instance to start the worker for
+ *
+ * Start the timeout for the given scheduler.
+ */
+static void drm_sched_start_timeout(struct drm_gpu_scheduler *sched)
+{
+	if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
+	    !list_empty(&sched->pending_list))
+		queue_delayed_work(sched->timeout_wq, &sched->work_tdr, sched->timeout);
+}
+
+/**
+ * drm_sched_fault - immediately start timeout handler
+ *
+ * @sched: scheduler where the timeout handling should be started.
+ *
+ * Start timeout handling immediately when the driver detects a hardware fault.
+ */
+void drm_sched_fault(struct drm_gpu_scheduler *sched)
+{
+	mod_delayed_work(sched->timeout_wq, &sched->work_tdr, 0);
+}
+EXPORT_SYMBOL(drm_sched_fault);
+
+/**
+ * drm_sched_suspend_timeout - Suspend scheduler job timeout
+ *
+ * @sched: scheduler instance for which to suspend the timeout
+ *
+ * Suspend the delayed work timeout for the scheduler. This is done by
+ * modifying the delayed work timeout to an arbitrary large value,
+ * MAX_SCHEDULE_TIMEOUT in this case.
+ *
+ * Returns the timeout remaining
+ *
+ */
+unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched)
+{
+	unsigned long sched_timeout, now = jiffies;
+
+	sched_timeout = sched->work_tdr.timer.expires;
+
+	/*
+	 * Modify the timeout to an arbitrarily large value. This also prevents
+	 * the timeout to be restarted when new submissions arrive
+	 */
+	if (mod_delayed_work(sched->timeout_wq, &sched->work_tdr, MAX_SCHEDULE_TIMEOUT)
+			&& time_after(sched_timeout, now))
+		return sched_timeout - now;
+	else
+		return sched->timeout;
+}
+EXPORT_SYMBOL(drm_sched_suspend_timeout);
+
+/**
+ * drm_sched_resume_timeout - Resume scheduler job timeout
+ *
+ * @sched: scheduler instance for which to resume the timeout
+ * @remaining: remaining timeout
+ *
+ * Resume the delayed work timeout for the scheduler.
+ */
+void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
+		unsigned long remaining)
+{
+	spin_lock(&sched->job_list_lock);
+
+	if (list_empty(&sched->pending_list))
+		cancel_delayed_work(&sched->work_tdr);
+	else
+		mod_delayed_work(sched->timeout_wq, &sched->work_tdr, remaining);
+
+	spin_unlock(&sched->job_list_lock);
+}
+EXPORT_SYMBOL(drm_sched_resume_timeout);
+
+static void drm_sched_job_begin(struct drm_sched_job *s_job)
+{
+	struct drm_gpu_scheduler *sched = s_job->sched;
+
+	spin_lock(&sched->job_list_lock);
+	list_add_tail(&s_job->list, &sched->pending_list);
+	drm_sched_start_timeout(sched);
+	spin_unlock(&sched->job_list_lock);
+}
+
+static void drm_sched_job_timedout(struct work_struct *work)
+{
+	struct drm_gpu_scheduler *sched;
+	struct drm_sched_job *job;
+	enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
+
+	sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
+
+	/* Protects against concurrent deletion in drm_sched_get_cleanup_job */
+	spin_lock(&sched->job_list_lock);
+	job = list_first_entry_or_null(&sched->pending_list,
+				       struct drm_sched_job, list);
+
+	if (job) {
+		/*
+		 * Remove the bad job so it cannot be freed by concurrent
+		 * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread
+		 * is parked at which point it's safe.
+		 */
+		list_del_init(&job->list);
+		spin_unlock(&sched->job_list_lock);
+
+		status = job->sched->ops->timedout_job(job);
+
+		/*
+		 * Guilty job did complete and hence needs to be manually removed
+		 * See drm_sched_stop doc.
+		 */
+		if (sched->free_guilty) {
+			job->sched->ops->free_job(job);
+			sched->free_guilty = false;
+		}
+	} else {
+		spin_unlock(&sched->job_list_lock);
+	}
+
+	if (status != DRM_GPU_SCHED_STAT_ENODEV) {
+		spin_lock(&sched->job_list_lock);
+		drm_sched_start_timeout(sched);
+		spin_unlock(&sched->job_list_lock);
+	}
+}
+
+ /**
+  * drm_sched_increase_karma - Update sched_entity guilty flag
+  *
+  * @bad: The job guilty of time out
+  *
+  * Increment on every hang caused by the 'bad' job. If this exceeds the hang
+  * limit of the scheduler then the respective sched entity is marked guilty and
+  * jobs from it will not be scheduled further
+  */
+void drm_sched_increase_karma(struct drm_sched_job *bad)
+{
+	drm_sched_increase_karma_ext(bad, 1);
+}
+EXPORT_SYMBOL(drm_sched_increase_karma);
+
+void drm_sched_reset_karma(struct drm_sched_job *bad)
+{
+	drm_sched_increase_karma_ext(bad, 0);
+}
+EXPORT_SYMBOL(drm_sched_reset_karma);
+
+/**
+ * drm_sched_stop - stop the scheduler
+ *
+ * @sched: scheduler instance
+ * @bad: job which caused the time out
+ *
+ * Stop the scheduler and also removes and frees all completed jobs.
+ * Note: bad job will not be freed as it might be used later and so it's
+ * callers responsibility to release it manually if it's not part of the
+ * pending list any more.
+ *
+ */
+void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
+{
+	struct drm_sched_job *s_job, *tmp;
+
+	kthread_park(sched->thread);
+
+	/*
+	 * Reinsert back the bad job here - now it's safe as
+	 * drm_sched_get_cleanup_job cannot race against us and release the
+	 * bad job at this point - we parked (waited for) any in progress
+	 * (earlier) cleanups and drm_sched_get_cleanup_job will not be called
+	 * now until the scheduler thread is unparked.
+	 */
+	if (bad && bad->sched == sched)
+		/*
+		 * Add at the head of the queue to reflect it was the earliest
+		 * job extracted.
+		 */
+		list_add(&bad->list, &sched->pending_list);
+
+	/*
+	 * Iterate the job list from later to  earlier one and either deactive
+	 * their HW callbacks or remove them from pending list if they already
+	 * signaled.
+	 * This iteration is thread safe as sched thread is stopped.
+	 */
+	list_for_each_entry_safe_reverse(s_job, tmp, &sched->pending_list,
+					 list) {
+		if (s_job->s_fence->parent &&
+		    dma_fence_remove_callback(s_job->s_fence->parent,
+					      &s_job->cb)) {
+			dma_fence_put(s_job->s_fence->parent);
+			s_job->s_fence->parent = NULL;
+			atomic_dec(&sched->hw_rq_count);
+		} else {
+			/*
+			 * remove job from pending_list.
+			 * Locking here is for concurrent resume timeout
+			 */
+			spin_lock(&sched->job_list_lock);
+			list_del_init(&s_job->list);
+			spin_unlock(&sched->job_list_lock);
+
+			/*
+			 * Wait for job's HW fence callback to finish using s_job
+			 * before releasing it.
+			 *
+			 * Job is still alive so fence refcount at least 1
+			 */
+			dma_fence_wait(&s_job->s_fence->finished, false);
+
+			/*
+			 * We must keep bad job alive for later use during
+			 * recovery by some of the drivers but leave a hint
+			 * that the guilty job must be released.
+			 */
+			if (bad != s_job)
+				sched->ops->free_job(s_job);
+			else
+				sched->free_guilty = true;
+		}
+	}
+
+	/*
+	 * Stop pending timer in flight as we rearm it in  drm_sched_start. This
+	 * avoids the pending timeout work in progress to fire right away after
+	 * this TDR finished and before the newly restarted jobs had a
+	 * chance to complete.
+	 */
+	cancel_delayed_work(&sched->work_tdr);
+}
+
+EXPORT_SYMBOL(drm_sched_stop);
+
+/**
+ * drm_sched_start - recover jobs after a reset
+ *
+ * @sched: scheduler instance
+ * @full_recovery: proceed with complete sched restart
+ *
+ */
+void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
+{
+	struct drm_sched_job *s_job, *tmp;
+	int r;
+
+	/*
+	 * Locking the list is not required here as the sched thread is parked
+	 * so no new jobs are being inserted or removed. Also concurrent
+	 * GPU recovers can't run in parallel.
+	 */
+	list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
+		struct dma_fence *fence = s_job->s_fence->parent;
+
+		atomic_inc(&sched->hw_rq_count);
+
+		if (!full_recovery)
+			continue;
+
+		if (fence) {
+			r = dma_fence_add_callback(fence, &s_job->cb,
+						   drm_sched_job_done_cb);
+			if (r == -ENOENT)
+				drm_sched_job_done(s_job);
+			else if (r)
+				DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
+					  r);
+		} else
+			drm_sched_job_done(s_job);
+	}
+
+	if (full_recovery) {
+		spin_lock(&sched->job_list_lock);
+		drm_sched_start_timeout(sched);
+		spin_unlock(&sched->job_list_lock);
+	}
+
+	kthread_unpark(sched->thread);
+}
+EXPORT_SYMBOL(drm_sched_start);
+
+/**
+ * drm_sched_resubmit_jobs - helper to relaunch jobs from the pending list
+ *
+ * @sched: scheduler instance
+ *
+ */
+void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
+{
+	drm_sched_resubmit_jobs_ext(sched, INT_MAX);
+}
+EXPORT_SYMBOL(drm_sched_resubmit_jobs);
+
+/**
+ * drm_sched_resubmit_jobs_ext - helper to relunch certain number of jobs from mirror ring list
+ *
+ * @sched: scheduler instance
+ * @max: job numbers to relaunch
+ *
+ */
+void drm_sched_resubmit_jobs_ext(struct drm_gpu_scheduler *sched, int max)
+{
+	struct drm_sched_job *s_job, *tmp;
+	uint64_t guilty_context;
+	bool found_guilty = false;
+	struct dma_fence *fence;
+	int i = 0;
+
+	list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
+		struct drm_sched_fence *s_fence = s_job->s_fence;
+
+		if (i >= max)
+			break;
+
+		if (!found_guilty && atomic_read(&s_job->karma) > sched->hang_limit) {
+			found_guilty = true;
+			guilty_context = s_job->s_fence->scheduled.context;
+		}
+
+		if (found_guilty && s_job->s_fence->scheduled.context == guilty_context)
+			dma_fence_set_error(&s_fence->finished, -ECANCELED);
+
+		fence = sched->ops->run_job(s_job);
+		i++;
+
+		if (IS_ERR_OR_NULL(fence)) {
+			if (IS_ERR(fence))
+				dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
+
+			s_job->s_fence->parent = NULL;
+		} else {
+
+			s_job->s_fence->parent = dma_fence_get(fence);
+
+			/* Drop for orignal kref_init */
+			dma_fence_put(fence);
+		}
+	}
+}
+EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
+
+/**
+ * drm_sched_job_init - init a scheduler job
+ * @job: scheduler job to init
+ * @entity: scheduler entity to use
+ * @owner: job owner for debugging
+ *
+ * Refer to drm_sched_entity_push_job() documentation
+ * for locking considerations.
+ *
+ * Drivers must make sure drm_sched_job_cleanup() if this function returns
+ * successfully, even when @job is aborted before drm_sched_job_arm() is called.
+ *
+ * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware
+ * has died, which can mean that there's no valid runqueue for a @entity.
+ * This function returns -ENOENT in this case (which probably should be -EIO as
+ * a more meanigful return value).
+ *
+ * Returns 0 for success, negative error code otherwise.
+ */
+int drm_sched_job_init(struct drm_sched_job *job,
+		       struct drm_sched_entity *entity,
+		       void *owner)
+{
+	if (!entity->rq)
+		return -ENOENT;
+
+	job->entity = entity;
+	job->s_fence = drm_sched_fence_alloc(entity, owner);
+	if (!job->s_fence)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&job->list);
+
+	xa_init_flags(&job->dependencies, XA_FLAGS_ALLOC);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_sched_job_init);
+
+/**
+ * drm_sched_job_arm - arm a scheduler job for execution
+ * @job: scheduler job to arm
+ *
+ * This arms a scheduler job for execution. Specifically it initializes the
+ * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv
+ * or other places that need to track the completion of this job.
+ *
+ * Refer to drm_sched_entity_push_job() documentation for locking
+ * considerations.
+ *
+ * This can only be called if drm_sched_job_init() succeeded.
+ */
+void drm_sched_job_arm(struct drm_sched_job *job)
+{
+	struct drm_gpu_scheduler *sched;
+	struct drm_sched_entity *entity = job->entity;
+
+	BUG_ON(!entity);
+	drm_sched_entity_select_rq(entity);
+	sched = entity->rq->sched;
+
+	job->sched = sched;
+	job->s_priority = entity->rq - sched->sched_rq;
+	job->id = atomic64_inc_return(&sched->job_id_count);
+
+	drm_sched_fence_init(job->s_fence, job->entity);
+}
+EXPORT_SYMBOL(drm_sched_job_arm);
+
+/**
+ * drm_sched_job_add_dependency - adds the fence as a job dependency
+ * @job: scheduler job to add the dependencies to
+ * @fence: the dma_fence to add to the list of dependencies.
+ *
+ * Note that @fence is consumed in both the success and error cases.
+ *
+ * Returns:
+ * 0 on success, or an error on failing to expand the array.
+ */
+int drm_sched_job_add_dependency(struct drm_sched_job *job,
+				 struct dma_fence *fence)
+{
+	struct dma_fence *entry;
+	unsigned long index;
+	u32 id = 0;
+	int ret;
+
+	if (!fence)
+		return 0;
+
+	/* Deduplicate if we already depend on a fence from the same context.
+	 * This lets the size of the array of deps scale with the number of
+	 * engines involved, rather than the number of BOs.
+	 */
+	xa_for_each(&job->dependencies, index, entry) {
+		if (entry->context != fence->context)
+			continue;
+
+		if (dma_fence_is_later(fence, entry)) {
+			dma_fence_put(entry);
+			xa_store(&job->dependencies, index, fence, GFP_KERNEL);
+		} else {
+			dma_fence_put(fence);
+		}
+		return 0;
+	}
+
+	ret = xa_alloc(&job->dependencies, &id, fence, xa_limit_32b, GFP_KERNEL);
+	if (ret != 0)
+		dma_fence_put(fence);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_sched_job_add_dependency);
+
+/**
+ * drm_sched_job_add_implicit_dependencies - adds implicit dependencies as job
+ *   dependencies
+ * @job: scheduler job to add the dependencies to
+ * @obj: the gem object to add new dependencies from.
+ * @write: whether the job might write the object (so we need to depend on
+ * shared fences in the reservation object).
+ *
+ * This should be called after drm_gem_lock_reservations() on your array of
+ * GEM objects used in the job but before updating the reservations with your
+ * own fences.
+ *
+ * Returns:
+ * 0 on success, or an error on failing to expand the array.
+ */
+int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
+					    struct drm_gem_object *obj,
+					    bool write)
+{
+	struct dma_resv_iter cursor;
+	struct dma_fence *fence;
+	int ret;
+
+	dma_resv_assert_held(obj->resv);
+
+	dma_resv_for_each_fence(&cursor, obj->resv, dma_resv_usage_rw(write),
+				fence) {
+		/* Make sure to grab an additional ref on the added fence */
+		dma_fence_get(fence);
+		ret = drm_sched_job_add_dependency(job, fence);
+		if (ret) {
+			dma_fence_put(fence);
+			return ret;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL(drm_sched_job_add_implicit_dependencies);
+
+
+/**
+ * drm_sched_job_cleanup - clean up scheduler job resources
+ * @job: scheduler job to clean up
+ *
+ * Cleans up the resources allocated with drm_sched_job_init().
+ *
+ * Drivers should call this from their error unwind code if @job is aborted
+ * before drm_sched_job_arm() is called.
+ *
+ * After that point of no return @job is committed to be executed by the
+ * scheduler, and this function should be called from the
+ * &drm_sched_backend_ops.free_job callback.
+ */
+void drm_sched_job_cleanup(struct drm_sched_job *job)
+{
+	struct dma_fence *fence;
+	unsigned long index;
+
+	if (kref_read(&job->s_fence->finished.refcount)) {
+		/* drm_sched_job_arm() has been called */
+		dma_fence_put(&job->s_fence->finished);
+	} else {
+		/* aborted job before committing to run it */
+		drm_sched_fence_free(job->s_fence);
+	}
+
+	job->s_fence = NULL;
+
+	xa_for_each(&job->dependencies, index, fence) {
+		dma_fence_put(fence);
+	}
+	xa_destroy(&job->dependencies);
+
+}
+EXPORT_SYMBOL(drm_sched_job_cleanup);
+
+/**
+ * drm_sched_ready - is the scheduler ready
+ *
+ * @sched: scheduler instance
+ *
+ * Return true if we can push more jobs to the hw, otherwise false.
+ */
+static bool drm_sched_ready(struct drm_gpu_scheduler *sched)
+{
+	return atomic_read(&sched->hw_rq_count) <
+		sched->hw_submission_limit;
+}
+
+/**
+ * drm_sched_wakeup - Wake up the scheduler when it is ready
+ *
+ * @sched: scheduler instance
+ *
+ */
+void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
+{
+	if (drm_sched_ready(sched))
+		wake_up_interruptible(&sched->wake_up_worker);
+}
+
+/**
+ * drm_sched_select_entity - Select next entity to process
+ *
+ * @sched: scheduler instance
+ *
+ * Returns the entity to process or NULL if none are found.
+ */
+static struct drm_sched_entity *
+drm_sched_select_entity(struct drm_gpu_scheduler *sched)
+{
+	struct drm_sched_entity *entity;
+	int i;
+
+	if (!drm_sched_ready(sched))
+		return NULL;
+
+	/* Kernel run queue has higher priority than normal run queue*/
+	for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
+		entity = drm_sched_rq_select_entity(&sched->sched_rq[i]);
+		if (entity)
+			break;
+	}
+
+	return entity;
+}
+
+/**
+ * drm_sched_get_cleanup_job - fetch the next finished job to be destroyed
+ *
+ * @sched: scheduler instance
+ *
+ * Returns the next finished job from the pending list (if there is one)
+ * ready for it to be destroyed.
+ */
+static struct drm_sched_job *
+drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
+{
+	struct drm_sched_job *job, *next;
+
+	spin_lock(&sched->job_list_lock);
+
+	job = list_first_entry_or_null(&sched->pending_list,
+				       struct drm_sched_job, list);
+
+	if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
+		/* remove job from pending_list */
+		list_del_init(&job->list);
+
+		/* cancel this job's TO timer */
+		cancel_delayed_work(&sched->work_tdr);
+		/* make the scheduled timestamp more accurate */
+		next = list_first_entry_or_null(&sched->pending_list,
+						typeof(*next), list);
+
+		if (next) {
+			next->s_fence->scheduled.timestamp =
+				dma_fence_timestamp(&job->s_fence->finished);
+			/* start TO timer for next job */
+			drm_sched_start_timeout(sched);
+		}
+	} else {
+		job = NULL;
+	}
+
+	spin_unlock(&sched->job_list_lock);
+
+	return job;
+}
+
+/**
+ * drm_sched_pick_best - Get a drm sched from a sched_list with the least load
+ * @sched_list: list of drm_gpu_schedulers
+ * @num_sched_list: number of drm_gpu_schedulers in the sched_list
+ *
+ * Returns pointer of the sched with the least load or NULL if none of the
+ * drm_gpu_schedulers are ready
+ */
+struct drm_gpu_scheduler *
+drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
+		     unsigned int num_sched_list)
+{
+	struct drm_gpu_scheduler *sched, *picked_sched = NULL;
+	int i;
+	unsigned int min_score = UINT_MAX, num_score;
+
+	for (i = 0; i < num_sched_list; ++i) {
+		sched = sched_list[i];
+
+		if (!sched->ready) {
+			DRM_WARN("scheduler %s is not ready, skipping",
+				 sched->name);
+			continue;
+		}
+
+		num_score = atomic_read(sched->score);
+		if (num_score < min_score) {
+			min_score = num_score;
+			picked_sched = sched;
+		}
+	}
+
+	return picked_sched;
+}
+EXPORT_SYMBOL(drm_sched_pick_best);
+
+/**
+ * drm_sched_blocked - check if the scheduler is blocked
+ *
+ * @sched: scheduler instance
+ *
+ * Returns true if blocked, otherwise false.
+ */
+static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
+{
+	if (kthread_should_park()) {
+		kthread_parkme();
+		return true;
+	}
+
+	return false;
+}
+
+/**
+ * drm_sched_main - main scheduler thread
+ *
+ * @param: scheduler instance
+ *
+ * Returns 0.
+ */
+static int drm_sched_main(void *param)
+{
+	struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
+	int r;
+
+	sched_set_fifo_low(current);
+
+	while (!kthread_should_stop()) {
+		struct drm_sched_entity *entity = NULL;
+		struct drm_sched_fence *s_fence;
+		struct drm_sched_job *sched_job;
+		struct dma_fence *fence;
+		struct drm_sched_job *cleanup_job = NULL;
+
+		wait_event_interruptible(sched->wake_up_worker,
+					 (cleanup_job = drm_sched_get_cleanup_job(sched)) ||
+					 (!drm_sched_blocked(sched) &&
+					  (entity = drm_sched_select_entity(sched))) ||
+					 kthread_should_stop());
+
+		if (cleanup_job)
+			sched->ops->free_job(cleanup_job);
+
+		if (!entity)
+			continue;
+
+		sched_job = drm_sched_entity_pop_job(entity);
+
+		if (!sched_job) {
+			complete(&entity->entity_idle);
+			continue;
+		}
+
+		s_fence = sched_job->s_fence;
+
+		atomic_inc(&sched->hw_rq_count);
+		drm_sched_job_begin(sched_job);
+
+		trace_drm_run_job(sched_job, entity);
+		fence = sched->ops->run_job(sched_job);
+		complete(&entity->entity_idle);
+		drm_sched_fence_scheduled(s_fence);
+
+		if (!IS_ERR_OR_NULL(fence)) {
+			s_fence->parent = dma_fence_get(fence);
+			/* Drop for original kref_init of the fence */
+			dma_fence_put(fence);
+
+			r = dma_fence_add_callback(fence, &sched_job->cb,
+						   drm_sched_job_done_cb);
+			if (r == -ENOENT)
+				drm_sched_job_done(sched_job);
+			else if (r)
+				DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
+					  r);
+		} else {
+			if (IS_ERR(fence))
+				dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
+
+			drm_sched_job_done(sched_job);
+		}
+
+		wake_up(&sched->job_scheduled);
+	}
+	return 0;
+}
+
+/**
+ * drm_sched_init - Init a gpu scheduler instance
+ *
+ * @sched: scheduler instance
+ * @ops: backend operations for this scheduler
+ * @hw_submission: number of hw submissions that can be in flight
+ * @hang_limit: number of times to allow a job to hang before dropping it
+ * @timeout: timeout value in jiffies for the scheduler
+ * @timeout_wq: workqueue to use for timeout work. If NULL, the system_wq is
+ *		used
+ * @score: optional score atomic shared with other schedulers
+ * @name: name used for debugging
+ * @dev: target &struct device
+ *
+ * Return 0 on success, otherwise error code.
+ */
+int drm_sched_init(struct drm_gpu_scheduler *sched,
+		   const struct drm_sched_backend_ops *ops,
+		   unsigned hw_submission, unsigned hang_limit,
+		   long timeout, struct workqueue_struct *timeout_wq,
+		   atomic_t *score, const char *name, struct device *dev)
+{
+	int i, ret;
+	sched->ops = ops;
+	sched->hw_submission_limit = hw_submission;
+	sched->name = name;
+	sched->timeout = timeout;
+	sched->timeout_wq = timeout_wq ? : system_wq;
+	sched->hang_limit = hang_limit;
+	sched->score = score ? score : &sched->_score;
+	sched->dev = dev;
+	for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_COUNT; i++)
+		drm_sched_rq_init(sched, &sched->sched_rq[i]);
+
+	init_waitqueue_head(&sched->wake_up_worker);
+	init_waitqueue_head(&sched->job_scheduled);
+	INIT_LIST_HEAD(&sched->pending_list);
+	spin_lock_init(&sched->job_list_lock);
+	atomic_set(&sched->hw_rq_count, 0);
+	INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
+	atomic_set(&sched->_score, 0);
+	atomic64_set(&sched->job_id_count, 0);
+
+	/* Each scheduler will run on a seperate kernel thread */
+	sched->thread = kthread_run(drm_sched_main, sched, sched->name);
+	if (IS_ERR(sched->thread)) {
+		ret = PTR_ERR(sched->thread);
+		sched->thread = NULL;
+		DRM_DEV_ERROR(sched->dev, "Failed to create scheduler for %s.\n", name);
+		return ret;
+	}
+
+	sched->ready = true;
+	return 0;
+}
+EXPORT_SYMBOL(drm_sched_init);
+
+/**
+ * drm_sched_fini - Destroy a gpu scheduler
+ *
+ * @sched: scheduler instance
+ *
+ * Tears down and cleans up the scheduler.
+ */
+void drm_sched_fini(struct drm_gpu_scheduler *sched)
+{
+	struct drm_sched_entity *s_entity;
+	int i;
+
+	if (sched->thread)
+		kthread_stop(sched->thread);
+
+	for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
+		struct drm_sched_rq *rq = &sched->sched_rq[i];
+
+		if (!rq)
+			continue;
+
+		spin_lock(&rq->lock);
+		list_for_each_entry(s_entity, &rq->entities, list)
+			/*
+			 * Prevents reinsertion and marks job_queue as idle,
+			 * it will removed from rq in drm_sched_entity_fini
+			 * eventually
+			 */
+			s_entity->stopped = true;
+		spin_unlock(&rq->lock);
+
+	}
+
+	/* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
+	wake_up_all(&sched->job_scheduled);
+
+	/* Confirm no work left behind accessing device structures */
+	cancel_delayed_work_sync(&sched->work_tdr);
+
+	sched->ready = false;
+}
+EXPORT_SYMBOL(drm_sched_fini);
+
+/**
+ * drm_sched_increase_karma_ext - Update sched_entity guilty flag
+ *
+ * @bad: The job guilty of time out
+ * @type: type for increase/reset karma
+ *
+ */
+void drm_sched_increase_karma_ext(struct drm_sched_job *bad, int type)
+{
+	int i;
+	struct drm_sched_entity *tmp;
+	struct drm_sched_entity *entity;
+	struct drm_gpu_scheduler *sched = bad->sched;
+
+	/* don't change @bad's karma if it's from KERNEL RQ,
+	 * because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
+	 * corrupt but keep in mind that kernel jobs always considered good.
+	 */
+	if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
+		if (type == 0)
+			atomic_set(&bad->karma, 0);
+		else if (type == 1)
+			atomic_inc(&bad->karma);
+
+		for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL;
+		     i++) {
+			struct drm_sched_rq *rq = &sched->sched_rq[i];
+
+			spin_lock(&rq->lock);
+			list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
+				if (bad->s_fence->scheduled.context ==
+				    entity->fence_context) {
+					if (entity->guilty)
+						atomic_set(entity->guilty, type);
+					break;
+				}
+			}
+			spin_unlock(&rq->lock);
+			if (&entity->list != &rq->entities)
+				break;
+		}
+	}
+}
+EXPORT_SYMBOL(drm_sched_increase_karma_ext);