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diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
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+/*
+ * 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.
+ *
+ */
+
+#ifndef _DRM_GPU_SCHEDULER_H_
+#define _DRM_GPU_SCHEDULER_H_
+
+#include <drm/spsc_queue.h>
+#include <linux/dma-fence.h>
+#include <linux/completion.h>
+#include <linux/xarray.h>
+#include <linux/workqueue.h>
+
+#define MAX_WAIT_SCHED_ENTITY_Q_EMPTY msecs_to_jiffies(1000)
+
+/**
+ * DRM_SCHED_FENCE_DONT_PIPELINE - Prefent dependency pipelining
+ *
+ * Setting this flag on a scheduler fence prevents pipelining of jobs depending
+ * on this fence. In other words we always insert a full CPU round trip before
+ * dependen jobs are pushed to the hw queue.
+ */
+#define DRM_SCHED_FENCE_DONT_PIPELINE DMA_FENCE_FLAG_USER_BITS
+
+struct drm_gem_object;
+
+struct drm_gpu_scheduler;
+struct drm_sched_rq;
+
+/* These are often used as an (initial) index
+ * to an array, and as such should start at 0.
+ */
+enum drm_sched_priority {
+ DRM_SCHED_PRIORITY_MIN,
+ DRM_SCHED_PRIORITY_NORMAL,
+ DRM_SCHED_PRIORITY_HIGH,
+ DRM_SCHED_PRIORITY_KERNEL,
+
+ DRM_SCHED_PRIORITY_COUNT
+};
+
+/**
+ * struct drm_sched_entity - A wrapper around a job queue (typically
+ * attached to the DRM file_priv).
+ *
+ * Entities will emit jobs in order to their corresponding hardware
+ * ring, and the scheduler will alternate between entities based on
+ * scheduling policy.
+ */
+struct drm_sched_entity {
+ /**
+ * @list:
+ *
+ * Used to append this struct to the list of entities in the runqueue
+ * @rq under &drm_sched_rq.entities.
+ *
+ * Protected by &drm_sched_rq.lock of @rq.
+ */
+ struct list_head list;
+
+ /**
+ * @rq:
+ *
+ * Runqueue on which this entity is currently scheduled.
+ *
+ * FIXME: Locking is very unclear for this. Writers are protected by
+ * @rq_lock, but readers are generally lockless and seem to just race
+ * with not even a READ_ONCE.
+ */
+ struct drm_sched_rq *rq;
+
+ /**
+ * @sched_list:
+ *
+ * A list of schedulers (struct drm_gpu_scheduler). Jobs from this entity can
+ * be scheduled on any scheduler on this list.
+ *
+ * This can be modified by calling drm_sched_entity_modify_sched().
+ * Locking is entirely up to the driver, see the above function for more
+ * details.
+ *
+ * This will be set to NULL if &num_sched_list equals 1 and @rq has been
+ * set already.
+ *
+ * FIXME: This means priority changes through
+ * drm_sched_entity_set_priority() will be lost henceforth in this case.
+ */
+ struct drm_gpu_scheduler **sched_list;
+
+ /**
+ * @num_sched_list:
+ *
+ * Number of drm_gpu_schedulers in the @sched_list.
+ */
+ unsigned int num_sched_list;
+
+ /**
+ * @priority:
+ *
+ * Priority of the entity. This can be modified by calling
+ * drm_sched_entity_set_priority(). Protected by &rq_lock.
+ */
+ enum drm_sched_priority priority;
+
+ /**
+ * @rq_lock:
+ *
+ * Lock to modify the runqueue to which this entity belongs.
+ */
+ spinlock_t rq_lock;
+
+ /**
+ * @job_queue: the list of jobs of this entity.
+ */
+ struct spsc_queue job_queue;
+
+ /**
+ * @fence_seq:
+ *
+ * A linearly increasing seqno incremented with each new
+ * &drm_sched_fence which is part of the entity.
+ *
+ * FIXME: Callers of drm_sched_job_arm() need to ensure correct locking,
+ * this doesn't need to be atomic.
+ */
+ atomic_t fence_seq;
+
+ /**
+ * @fence_context:
+ *
+ * A unique context for all the fences which belong to this entity. The
+ * &drm_sched_fence.scheduled uses the fence_context but
+ * &drm_sched_fence.finished uses fence_context + 1.
+ */
+ uint64_t fence_context;
+
+ /**
+ * @dependency:
+ *
+ * The dependency fence of the job which is on the top of the job queue.
+ */
+ struct dma_fence *dependency;
+
+ /**
+ * @cb:
+ *
+ * Callback for the dependency fence above.
+ */
+ struct dma_fence_cb cb;
+
+ /**
+ * @guilty:
+ *
+ * Points to entities' guilty.
+ */
+ atomic_t *guilty;
+
+ /**
+ * @last_scheduled:
+ *
+ * Points to the finished fence of the last scheduled job. Only written
+ * by the scheduler thread, can be accessed locklessly from
+ * drm_sched_job_arm() iff the queue is empty.
+ */
+ struct dma_fence *last_scheduled;
+
+ /**
+ * @last_user: last group leader pushing a job into the entity.
+ */
+ struct task_struct *last_user;
+
+ /**
+ * @stopped:
+ *
+ * Marks the enity as removed from rq and destined for
+ * termination. This is set by calling drm_sched_entity_flush() and by
+ * drm_sched_fini().
+ */
+ bool stopped;
+
+ /**
+ * @entity_idle:
+ *
+ * Signals when entity is not in use, used to sequence entity cleanup in
+ * drm_sched_entity_fini().
+ */
+ struct completion entity_idle;
+};
+
+/**
+ * struct drm_sched_rq - queue of entities to be scheduled.
+ *
+ * @lock: to modify the entities list.
+ * @sched: the scheduler to which this rq belongs to.
+ * @entities: list of the entities to be scheduled.
+ * @current_entity: the entity which is to be scheduled.
+ *
+ * Run queue is a set of entities scheduling command submissions for
+ * one specific ring. It implements the scheduling policy that selects
+ * the next entity to emit commands from.
+ */
+struct drm_sched_rq {
+ spinlock_t lock;
+ struct drm_gpu_scheduler *sched;
+ struct list_head entities;
+ struct drm_sched_entity *current_entity;
+};
+
+/**
+ * struct drm_sched_fence - fences corresponding to the scheduling of a job.
+ */
+struct drm_sched_fence {
+ /**
+ * @scheduled: this fence is what will be signaled by the scheduler
+ * when the job is scheduled.
+ */
+ struct dma_fence scheduled;
+
+ /**
+ * @finished: this fence is what will be signaled by the scheduler
+ * when the job is completed.
+ *
+ * When setting up an out fence for the job, you should use
+ * this, since it's available immediately upon
+ * drm_sched_job_init(), and the fence returned by the driver
+ * from run_job() won't be created until the dependencies have
+ * resolved.
+ */
+ struct dma_fence finished;
+
+ /**
+ * @parent: the fence returned by &drm_sched_backend_ops.run_job
+ * when scheduling the job on hardware. We signal the
+ * &drm_sched_fence.finished fence once parent is signalled.
+ */
+ struct dma_fence *parent;
+ /**
+ * @sched: the scheduler instance to which the job having this struct
+ * belongs to.
+ */
+ struct drm_gpu_scheduler *sched;
+ /**
+ * @lock: the lock used by the scheduled and the finished fences.
+ */
+ spinlock_t lock;
+ /**
+ * @owner: job owner for debugging
+ */
+ void *owner;
+};
+
+struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f);
+
+/**
+ * struct drm_sched_job - A job to be run by an entity.
+ *
+ * @queue_node: used to append this struct to the queue of jobs in an entity.
+ * @list: a job participates in a "pending" and "done" lists.
+ * @sched: the scheduler instance on which this job is scheduled.
+ * @s_fence: contains the fences for the scheduling of job.
+ * @finish_cb: the callback for the finished fence.
+ * @work: Helper to reschdeule job kill to different context.
+ * @id: a unique id assigned to each job scheduled on the scheduler.
+ * @karma: increment on every hang caused by this job. If this exceeds the hang
+ * limit of the scheduler then the job is marked guilty and will not
+ * be scheduled further.
+ * @s_priority: the priority of the job.
+ * @entity: the entity to which this job belongs.
+ * @cb: the callback for the parent fence in s_fence.
+ *
+ * A job is created by the driver using drm_sched_job_init(), and
+ * should call drm_sched_entity_push_job() once it wants the scheduler
+ * to schedule the job.
+ */
+struct drm_sched_job {
+ struct spsc_node queue_node;
+ struct list_head list;
+ struct drm_gpu_scheduler *sched;
+ struct drm_sched_fence *s_fence;
+
+ /*
+ * work is used only after finish_cb has been used and will not be
+ * accessed anymore.
+ */
+ union {
+ struct dma_fence_cb finish_cb;
+ struct work_struct work;
+ };
+
+ uint64_t id;
+ atomic_t karma;
+ enum drm_sched_priority s_priority;
+ struct drm_sched_entity *entity;
+ struct dma_fence_cb cb;
+ /**
+ * @dependencies:
+ *
+ * Contains the dependencies as struct dma_fence for this job, see
+ * drm_sched_job_add_dependency() and
+ * drm_sched_job_add_implicit_dependencies().
+ */
+ struct xarray dependencies;
+
+ /** @last_dependency: tracks @dependencies as they signal */
+ unsigned long last_dependency;
+};
+
+static inline bool drm_sched_invalidate_job(struct drm_sched_job *s_job,
+ int threshold)
+{
+ return s_job && atomic_inc_return(&s_job->karma) > threshold;
+}
+
+enum drm_gpu_sched_stat {
+ DRM_GPU_SCHED_STAT_NONE, /* Reserve 0 */
+ DRM_GPU_SCHED_STAT_NOMINAL,
+ DRM_GPU_SCHED_STAT_ENODEV,
+};
+
+/**
+ * struct drm_sched_backend_ops - Define the backend operations
+ * called by the scheduler
+ *
+ * These functions should be implemented in the driver side.
+ */
+struct drm_sched_backend_ops {
+ /**
+ * @dependency:
+ *
+ * Called when the scheduler is considering scheduling this job next, to
+ * get another struct dma_fence for this job to block on. Once it
+ * returns NULL, run_job() may be called.
+ *
+ * If a driver exclusively uses drm_sched_job_add_dependency() and
+ * drm_sched_job_add_implicit_dependencies() this can be ommitted and
+ * left as NULL.
+ */
+ struct dma_fence *(*dependency)(struct drm_sched_job *sched_job,
+ struct drm_sched_entity *s_entity);
+
+ /**
+ * @run_job: Called to execute the job once all of the dependencies
+ * have been resolved. This may be called multiple times, if
+ * timedout_job() has happened and drm_sched_job_recovery()
+ * decides to try it again.
+ */
+ struct dma_fence *(*run_job)(struct drm_sched_job *sched_job);
+
+ /**
+ * @timedout_job: Called when a job has taken too long to execute,
+ * to trigger GPU recovery.
+ *
+ * This method is called in a workqueue context.
+ *
+ * Drivers typically issue a reset to recover from GPU hangs, and this
+ * procedure usually follows the following workflow:
+ *
+ * 1. Stop the scheduler using drm_sched_stop(). This will park the
+ * scheduler thread and cancel the timeout work, guaranteeing that
+ * nothing is queued while we reset the hardware queue
+ * 2. Try to gracefully stop non-faulty jobs (optional)
+ * 3. Issue a GPU reset (driver-specific)
+ * 4. Re-submit jobs using drm_sched_resubmit_jobs()
+ * 5. Restart the scheduler using drm_sched_start(). At that point, new
+ * jobs can be queued, and the scheduler thread is unblocked
+ *
+ * Note that some GPUs have distinct hardware queues but need to reset
+ * the GPU globally, which requires extra synchronization between the
+ * timeout handler of the different &drm_gpu_scheduler. One way to
+ * achieve this synchronization is to create an ordered workqueue
+ * (using alloc_ordered_workqueue()) at the driver level, and pass this
+ * queue to drm_sched_init(), to guarantee that timeout handlers are
+ * executed sequentially. The above workflow needs to be slightly
+ * adjusted in that case:
+ *
+ * 1. Stop all schedulers impacted by the reset using drm_sched_stop()
+ * 2. Try to gracefully stop non-faulty jobs on all queues impacted by
+ * the reset (optional)
+ * 3. Issue a GPU reset on all faulty queues (driver-specific)
+ * 4. Re-submit jobs on all schedulers impacted by the reset using
+ * drm_sched_resubmit_jobs()
+ * 5. Restart all schedulers that were stopped in step #1 using
+ * drm_sched_start()
+ *
+ * Return DRM_GPU_SCHED_STAT_NOMINAL, when all is normal,
+ * and the underlying driver has started or completed recovery.
+ *
+ * Return DRM_GPU_SCHED_STAT_ENODEV, if the device is no longer
+ * available, i.e. has been unplugged.
+ */
+ enum drm_gpu_sched_stat (*timedout_job)(struct drm_sched_job *sched_job);
+
+ /**
+ * @free_job: Called once the job's finished fence has been signaled
+ * and it's time to clean it up.
+ */
+ void (*free_job)(struct drm_sched_job *sched_job);
+};
+
+/**
+ * struct drm_gpu_scheduler - scheduler instance-specific data
+ *
+ * @ops: backend operations provided by the driver.
+ * @hw_submission_limit: the max size of the hardware queue.
+ * @timeout: the time after which a job is removed from the scheduler.
+ * @name: name of the ring for which this scheduler is being used.
+ * @sched_rq: priority wise array of run queues.
+ * @wake_up_worker: the wait queue on which the scheduler sleeps until a job
+ * is ready to be scheduled.
+ * @job_scheduled: once @drm_sched_entity_do_release is called the scheduler
+ * waits on this wait queue until all the scheduled jobs are
+ * finished.
+ * @hw_rq_count: the number of jobs currently in the hardware queue.
+ * @job_id_count: used to assign unique id to the each job.
+ * @timeout_wq: workqueue used to queue @work_tdr
+ * @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the
+ * timeout interval is over.
+ * @thread: the kthread on which the scheduler which run.
+ * @pending_list: the list of jobs which are currently in the job queue.
+ * @job_list_lock: lock to protect the pending_list.
+ * @hang_limit: once the hangs by a job crosses this limit then it is marked
+ * guilty and it will no longer be considered for scheduling.
+ * @score: score to help loadbalancer pick a idle sched
+ * @_score: score used when the driver doesn't provide one
+ * @ready: marks if the underlying HW is ready to work
+ * @free_guilty: A hit to time out handler to free the guilty job.
+ * @dev: system &struct device
+ *
+ * One scheduler is implemented for each hardware ring.
+ */
+struct drm_gpu_scheduler {
+ const struct drm_sched_backend_ops *ops;
+ uint32_t hw_submission_limit;
+ long timeout;
+ const char *name;
+ struct drm_sched_rq sched_rq[DRM_SCHED_PRIORITY_COUNT];
+ wait_queue_head_t wake_up_worker;
+ wait_queue_head_t job_scheduled;
+ atomic_t hw_rq_count;
+ atomic64_t job_id_count;
+ struct workqueue_struct *timeout_wq;
+ struct delayed_work work_tdr;
+ struct task_struct *thread;
+ struct list_head pending_list;
+ spinlock_t job_list_lock;
+ int hang_limit;
+ atomic_t *score;
+ atomic_t _score;
+ bool ready;
+ bool free_guilty;
+ struct device *dev;
+};
+
+int drm_sched_init(struct drm_gpu_scheduler *sched,
+ const struct drm_sched_backend_ops *ops,
+ uint32_t hw_submission, unsigned hang_limit,
+ long timeout, struct workqueue_struct *timeout_wq,
+ atomic_t *score, const char *name, struct device *dev);
+
+void drm_sched_fini(struct drm_gpu_scheduler *sched);
+int drm_sched_job_init(struct drm_sched_job *job,
+ struct drm_sched_entity *entity,
+ void *owner);
+void drm_sched_job_arm(struct drm_sched_job *job);
+int drm_sched_job_add_dependency(struct drm_sched_job *job,
+ struct dma_fence *fence);
+int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
+ struct drm_gem_object *obj,
+ bool write);
+
+
+void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
+ struct drm_gpu_scheduler **sched_list,
+ unsigned int num_sched_list);
+
+void drm_sched_job_cleanup(struct drm_sched_job *job);
+void drm_sched_wakeup(struct drm_gpu_scheduler *sched);
+void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad);
+void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery);
+void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched);
+void drm_sched_resubmit_jobs_ext(struct drm_gpu_scheduler *sched, int max);
+void drm_sched_increase_karma(struct drm_sched_job *bad);
+void drm_sched_reset_karma(struct drm_sched_job *bad);
+void drm_sched_increase_karma_ext(struct drm_sched_job *bad, int type);
+bool drm_sched_dependency_optimized(struct dma_fence* fence,
+ struct drm_sched_entity *entity);
+void drm_sched_fault(struct drm_gpu_scheduler *sched);
+void drm_sched_job_kickout(struct drm_sched_job *s_job);
+
+void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
+ struct drm_sched_entity *entity);
+void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
+ struct drm_sched_entity *entity);
+
+int drm_sched_entity_init(struct drm_sched_entity *entity,
+ enum drm_sched_priority priority,
+ struct drm_gpu_scheduler **sched_list,
+ unsigned int num_sched_list,
+ atomic_t *guilty);
+long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout);
+void drm_sched_entity_fini(struct drm_sched_entity *entity);
+void drm_sched_entity_destroy(struct drm_sched_entity *entity);
+void drm_sched_entity_select_rq(struct drm_sched_entity *entity);
+struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity);
+void drm_sched_entity_push_job(struct drm_sched_job *sched_job);
+void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
+ enum drm_sched_priority priority);
+bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
+
+struct drm_sched_fence *drm_sched_fence_alloc(
+ struct drm_sched_entity *s_entity, void *owner);
+void drm_sched_fence_init(struct drm_sched_fence *fence,
+ struct drm_sched_entity *entity);
+void drm_sched_fence_free(struct drm_sched_fence *fence);
+
+void drm_sched_fence_scheduled(struct drm_sched_fence *fence);
+void drm_sched_fence_finished(struct drm_sched_fence *fence);
+
+unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched);
+void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
+ unsigned long remaining);
+struct drm_gpu_scheduler *
+drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
+ unsigned int num_sched_list);
+
+#endif