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 #ifndef _DRM_GPU_SCHEDULER_H_
25 #define _DRM_GPU_SCHEDULER_H_
26 
27 #include <drm/spsc_queue.h>
28 #include <linux/dma-fence.h>
29 
30 #define MAX_WAIT_SCHED_ENTITY_Q_EMPTY msecs_to_jiffies(1000)
31 
32 struct drm_gpu_scheduler;
33 struct drm_sched_rq;
34 
35 enum drm_sched_priority {
36 	DRM_SCHED_PRIORITY_MIN,
37 	DRM_SCHED_PRIORITY_LOW = DRM_SCHED_PRIORITY_MIN,
38 	DRM_SCHED_PRIORITY_NORMAL,
39 	DRM_SCHED_PRIORITY_HIGH_SW,
40 	DRM_SCHED_PRIORITY_HIGH_HW,
41 	DRM_SCHED_PRIORITY_KERNEL,
42 	DRM_SCHED_PRIORITY_MAX,
43 	DRM_SCHED_PRIORITY_INVALID = -1,
44 	DRM_SCHED_PRIORITY_UNSET = -2
45 };
46 
47 /**
48  * struct drm_sched_entity - A wrapper around a job queue (typically
49  * attached to the DRM file_priv).
50  *
51  * @list: used to append this struct to the list of entities in the
52  *        runqueue.
53  * @rq: runqueue to which this entity belongs.
54  * @rq_lock: lock to modify the runqueue to which this entity belongs.
55  * @job_queue: the list of jobs of this entity.
56  * @fence_seq: a linearly increasing seqno incremented with each
57  *             new &drm_sched_fence which is part of the entity.
58  * @fence_context: a unique context for all the fences which belong
59  *                 to this entity.
60  *                 The &drm_sched_fence.scheduled uses the
61  *                 fence_context but &drm_sched_fence.finished uses
62  *                 fence_context + 1.
63  * @dependency: the dependency fence of the job which is on the top
64  *              of the job queue.
65  * @cb: callback for the dependency fence above.
66  * @guilty: points to ctx's guilty.
67  * @fini_status: contains the exit status in case the process was signalled.
68  * @last_scheduled: points to the finished fence of the last scheduled job.
69  * @last_user: last group leader pushing a job into the entity.
70  *
71  * Entities will emit jobs in order to their corresponding hardware
72  * ring, and the scheduler will alternate between entities based on
73  * scheduling policy.
74  */
75 struct drm_sched_entity {
76 	struct list_head		list;
77 	struct drm_sched_rq		*rq;
78 	spinlock_t			rq_lock;
79 
80 	struct spsc_queue		job_queue;
81 
82 	atomic_t			fence_seq;
83 	uint64_t			fence_context;
84 
85 	struct dma_fence		*dependency;
86 	struct dma_fence_cb		cb;
87 	atomic_t			*guilty;
88 	struct dma_fence                *last_scheduled;
89 	struct task_struct		*last_user;
90 };
91 
92 /**
93  * struct drm_sched_rq - queue of entities to be scheduled.
94  *
95  * @lock: to modify the entities list.
96  * @sched: the scheduler to which this rq belongs to.
97  * @entities: list of the entities to be scheduled.
98  * @current_entity: the entity which is to be scheduled.
99  *
100  * Run queue is a set of entities scheduling command submissions for
101  * one specific ring. It implements the scheduling policy that selects
102  * the next entity to emit commands from.
103  */
104 struct drm_sched_rq {
105 	spinlock_t			lock;
106 	struct drm_gpu_scheduler	*sched;
107 	struct list_head		entities;
108 	struct drm_sched_entity		*current_entity;
109 };
110 
111 /**
112  * struct drm_sched_fence - fences corresponding to the scheduling of a job.
113  */
114 struct drm_sched_fence {
115         /**
116          * @scheduled: this fence is what will be signaled by the scheduler
117          * when the job is scheduled.
118          */
119 	struct dma_fence		scheduled;
120 
121         /**
122          * @finished: this fence is what will be signaled by the scheduler
123          * when the job is completed.
124          *
125          * When setting up an out fence for the job, you should use
126          * this, since it's available immediately upon
127          * drm_sched_job_init(), and the fence returned by the driver
128          * from run_job() won't be created until the dependencies have
129          * resolved.
130          */
131 	struct dma_fence		finished;
132 
133         /**
134          * @cb: the callback for the parent fence below.
135          */
136 	struct dma_fence_cb		cb;
137         /**
138          * @parent: the fence returned by &drm_sched_backend_ops.run_job
139          * when scheduling the job on hardware. We signal the
140          * &drm_sched_fence.finished fence once parent is signalled.
141          */
142 	struct dma_fence		*parent;
143         /**
144          * @sched: the scheduler instance to which the job having this struct
145          * belongs to.
146          */
147 	struct drm_gpu_scheduler	*sched;
148         /**
149          * @lock: the lock used by the scheduled and the finished fences.
150          */
151 	spinlock_t			lock;
152         /**
153          * @owner: job owner for debugging
154          */
155 	void				*owner;
156 };
157 
158 struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f);
159 
160 /**
161  * struct drm_sched_job - A job to be run by an entity.
162  *
163  * @queue_node: used to append this struct to the queue of jobs in an entity.
164  * @sched: the scheduler instance on which this job is scheduled.
165  * @s_fence: contains the fences for the scheduling of job.
166  * @finish_cb: the callback for the finished fence.
167  * @finish_work: schedules the function @drm_sched_job_finish once the job has
168  *               finished to remove the job from the
169  *               @drm_gpu_scheduler.ring_mirror_list.
170  * @node: used to append this struct to the @drm_gpu_scheduler.ring_mirror_list.
171  * @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the timeout
172  *            interval is over.
173  * @id: a unique id assigned to each job scheduled on the scheduler.
174  * @karma: increment on every hang caused by this job. If this exceeds the hang
175  *         limit of the scheduler then the job is marked guilty and will not
176  *         be scheduled further.
177  * @s_priority: the priority of the job.
178  * @entity: the entity to which this job belongs.
179  *
180  * A job is created by the driver using drm_sched_job_init(), and
181  * should call drm_sched_entity_push_job() once it wants the scheduler
182  * to schedule the job.
183  */
184 struct drm_sched_job {
185 	struct spsc_node		queue_node;
186 	struct drm_gpu_scheduler	*sched;
187 	struct drm_sched_fence		*s_fence;
188 	struct dma_fence_cb		finish_cb;
189 	struct work_struct		finish_work;
190 	struct list_head		node;
191 	struct delayed_work		work_tdr;
192 	uint64_t			id;
193 	atomic_t			karma;
194 	enum drm_sched_priority		s_priority;
195 	struct drm_sched_entity  *entity;
196 };
197 
drm_sched_invalidate_job(struct drm_sched_job * s_job,int threshold)198 static inline bool drm_sched_invalidate_job(struct drm_sched_job *s_job,
199 					    int threshold)
200 {
201 	return (s_job && atomic_inc_return(&s_job->karma) > threshold);
202 }
203 
204 /**
205  * struct drm_sched_backend_ops
206  *
207  * Define the backend operations called by the scheduler,
208  * these functions should be implemented in driver side.
209  */
210 struct drm_sched_backend_ops {
211 	/**
212          * @dependency: Called when the scheduler is considering scheduling
213          * this job next, to get another struct dma_fence for this job to
214 	 * block on.  Once it returns NULL, run_job() may be called.
215 	 */
216 	struct dma_fence *(*dependency)(struct drm_sched_job *sched_job,
217 					struct drm_sched_entity *s_entity);
218 
219 	/**
220          * @run_job: Called to execute the job once all of the dependencies
221          * have been resolved.  This may be called multiple times, if
222 	 * timedout_job() has happened and drm_sched_job_recovery()
223 	 * decides to try it again.
224 	 */
225 	struct dma_fence *(*run_job)(struct drm_sched_job *sched_job);
226 
227 	/**
228          * @timedout_job: Called when a job has taken too long to execute,
229          * to trigger GPU recovery.
230 	 */
231 	void (*timedout_job)(struct drm_sched_job *sched_job);
232 
233 	/**
234          * @free_job: Called once the job's finished fence has been signaled
235          * and it's time to clean it up.
236 	 */
237 	void (*free_job)(struct drm_sched_job *sched_job);
238 };
239 
240 /**
241  * struct drm_gpu_scheduler
242  *
243  * @ops: backend operations provided by the driver.
244  * @hw_submission_limit: the max size of the hardware queue.
245  * @timeout: the time after which a job is removed from the scheduler.
246  * @name: name of the ring for which this scheduler is being used.
247  * @sched_rq: priority wise array of run queues.
248  * @wake_up_worker: the wait queue on which the scheduler sleeps until a job
249  *                  is ready to be scheduled.
250  * @job_scheduled: once @drm_sched_entity_do_release is called the scheduler
251  *                 waits on this wait queue until all the scheduled jobs are
252  *                 finished.
253  * @hw_rq_count: the number of jobs currently in the hardware queue.
254  * @job_id_count: used to assign unique id to the each job.
255  * @thread: the kthread on which the scheduler which run.
256  * @ring_mirror_list: the list of jobs which are currently in the job queue.
257  * @job_list_lock: lock to protect the ring_mirror_list.
258  * @hang_limit: once the hangs by a job crosses this limit then it is marked
259  *              guilty and it will be considered for scheduling further.
260  *
261  * One scheduler is implemented for each hardware ring.
262  */
263 struct drm_gpu_scheduler {
264 	const struct drm_sched_backend_ops	*ops;
265 	uint32_t			hw_submission_limit;
266 	long				timeout;
267 	const char			*name;
268 	struct drm_sched_rq		sched_rq[DRM_SCHED_PRIORITY_MAX];
269 	wait_queue_head_t		wake_up_worker;
270 	wait_queue_head_t		job_scheduled;
271 	atomic_t			hw_rq_count;
272 	atomic64_t			job_id_count;
273 	struct task_struct		*thread;
274 	struct list_head		ring_mirror_list;
275 	spinlock_t			job_list_lock;
276 	int				hang_limit;
277 };
278 
279 int drm_sched_init(struct drm_gpu_scheduler *sched,
280 		   const struct drm_sched_backend_ops *ops,
281 		   uint32_t hw_submission, unsigned hang_limit, long timeout,
282 		   const char *name);
283 void drm_sched_fini(struct drm_gpu_scheduler *sched);
284 
285 int drm_sched_entity_init(struct drm_sched_entity *entity,
286 			  struct drm_sched_rq **rq_list,
287 			  unsigned int num_rq_list,
288 			  atomic_t *guilty);
289 long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout);
290 void drm_sched_entity_fini(struct drm_sched_entity *entity);
291 void drm_sched_entity_destroy(struct drm_sched_entity *entity);
292 void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
293 			       struct drm_sched_entity *entity);
294 void drm_sched_entity_set_rq(struct drm_sched_entity *entity,
295 			     struct drm_sched_rq *rq);
296 
297 struct drm_sched_fence *drm_sched_fence_create(
298 	struct drm_sched_entity *s_entity, void *owner);
299 void drm_sched_fence_scheduled(struct drm_sched_fence *fence);
300 void drm_sched_fence_finished(struct drm_sched_fence *fence);
301 int drm_sched_job_init(struct drm_sched_job *job,
302 		       struct drm_sched_entity *entity,
303 		       void *owner);
304 void drm_sched_hw_job_reset(struct drm_gpu_scheduler *sched,
305 			    struct drm_sched_job *job);
306 void drm_sched_job_recovery(struct drm_gpu_scheduler *sched);
307 bool drm_sched_dependency_optimized(struct dma_fence* fence,
308 				    struct drm_sched_entity *entity);
309 void drm_sched_job_kickout(struct drm_sched_job *s_job);
310 
311 #endif
312