drm/amd: add basic scheduling framework

run queue:
A set of entities scheduling commands for the same ring. It
implements the scheduling policy that selects the next entity to
emit commands from.

entity:
A scheduler entity is a wrapper around a job queue or a group of
other entities. This can be used to build hierarchies of entities.
For example all job queue entities belonging to the same process
may be placed in a higher level entity and scheduled against other
process entities.
Entities take turns emitting jobs from their job queue to the
corresponding hardware ring, in accordance with the scheduler policy.
Signed-off-by: Shaoyun Liu <Shaoyun.Liu@amd.com>
Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
Signed-off-by: Jammy Zhou <Jammy.Zhou@amd.com>
Acked-by: Christian K?nig <christian.koenig@amd.com>
Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>

drivers/gpu/drm/amd/scheduler/gpu_scheduler.h

+/*
+ * 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 _GPU_SCHEDULER_H_
+#define _GPU_SCHEDULER_H_
+
+#include <linux/kfifo.h>
+
+#define AMD_MAX_ACTIVE_HW_SUBMISSION		2
+#define AMD_MAX_JOB_ENTRY_PER_CONTEXT		16
+
+#define AMD_KERNEL_CONTEXT_ID			0
+#define AMD_KERNEL_PROCESS_ID			0
+
+#define AMD_GPU_WAIT_IDLE_TIMEOUT_IN_MS		3000
+
+struct amd_gpu_scheduler;
+struct amd_run_queue;
+
+/**
+ * A scheduler entity is a wrapper around a job queue or a group
+ * of other entities. Entities take turns emitting jobs from their 
+ * job queues to corresponding hardware ring based on scheduling
+ * policy.
+*/
+struct amd_sched_entity {
+	struct list_head		list;
+	struct amd_run_queue		*belongto_rq;
+	struct amd_sched_entity	        *parent;
+};
+
+/**
+ * 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 amd_run_queue {
+	struct mutex			lock;
+	atomic_t			nr_entity;
+	struct amd_sched_entity	        head;
+	struct amd_sched_entity	        *current_entity;
+	/**
+	 * Return 0 means this entity can be scheduled
+	 * Return -1 means this entity cannot be scheduled for reasons,
+	 * i.e, it is the head, or these is no job, etc
+	*/
+	int (*check_entity_status)(struct amd_sched_entity *entity);
+};
+
+/**
+ * Context based scheduler entity, there can be multiple entities for
+ * each context, and one entity per ring
+*/
+struct amd_context_entity {
+	struct amd_sched_entity	        generic_entity;
+	spinlock_t			lock;
+	/* the virtual_seq is unique per context per ring */
+	atomic64_t			last_queued_v_seq;
+	atomic64_t			last_emitted_v_seq;
+	atomic64_t			last_signaled_v_seq;
+	pid_t				tgid;
+	uint32_t			context_id;
+	/* the job_queue maintains the jobs submitted by clients */
+	struct kfifo                    job_queue;
+	spinlock_t			queue_lock;
+	struct amd_gpu_scheduler	*scheduler;
+	wait_queue_head_t		wait_queue;
+	wait_queue_head_t		wait_emit;
+	bool                            is_pending;
+};
+
+/**
+ * Define the backend operations called by the scheduler,
+ * these functions should be implemented in driver side
+*/
+struct amd_sched_backend_ops {
+	int (*prepare_job)(struct amd_gpu_scheduler *sched,
+			   struct amd_context_entity *c_entity,
+			   void *job);
+	void (*run_job)(struct amd_gpu_scheduler *sched,
+			struct amd_context_entity *c_entity,
+			void *job);
+	void (*process_job)(struct amd_gpu_scheduler *sched, void *job);
+};
+
+/**
+ * One scheduler is implemented for each hardware ring
+*/
+struct amd_gpu_scheduler {
+	void			        *device;
+	struct task_struct		*thread;
+	struct amd_run_queue		sched_rq;
+	struct amd_run_queue		kernel_rq;
+	struct kfifo                    active_hw_rq;
+	struct amd_sched_backend_ops	*ops;
+	uint32_t			ring_id;
+	uint32_t			granularity; /* in ms unit */
+	uint32_t			preemption;
+	uint64_t                        last_handled_seq;
+	wait_queue_head_t		wait_queue;
+	struct amd_context_entity	*current_entity;
+	struct mutex			sched_lock;
+	spinlock_t			queue_lock;
+};
+
+
+struct amd_gpu_scheduler *amd_sched_create(void *device,
+				struct amd_sched_backend_ops *ops,
+				uint32_t ring,
+				uint32_t granularity,
+				uint32_t preemption);
+
+int amd_sched_destroy(struct amd_gpu_scheduler *sched);
+
+int amd_sched_push_job(struct amd_gpu_scheduler *sched,
+		       struct amd_context_entity *c_entity,
+		       void *job);
+
+int amd_sched_check_ts(struct amd_context_entity *c_entity, uint64_t seq);
+
+int amd_sched_wait_signal(struct amd_context_entity *c_entity,
+			  uint64_t seq, bool intr, long timeout);
+int amd_sched_wait_emit(struct amd_context_entity *c_entity,
+			uint64_t seq,
+			bool intr,
+			long timeout);
+
+void amd_sched_isr(struct amd_gpu_scheduler *sched);
+uint64_t amd_sched_get_handled_seq(struct amd_gpu_scheduler *sched);
+
+int amd_context_entity_fini(struct amd_gpu_scheduler *sched,
+			    struct amd_context_entity *entity);
+
+int amd_context_entity_init(struct amd_gpu_scheduler *sched,
+			    struct amd_context_entity *entity,
+			    struct amd_sched_entity *parent,
+			    struct amd_run_queue *rq,
+			    uint32_t context_id);
+
+#endif