sync.h revision ae66475289d13ef724cd5a523a4a5ce42e81582b 
1/*
2 * include/linux/sync.h
3 *
4 * Copyright (C) 2012 Google, Inc.
5 *
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
9 * GNU General Public License for more details.
10 *
11 */
12
13#ifndef _LINUX_SYNC_H
14#define _LINUX_SYNC_H
15
16#include <linux/types.h>
17#include <linux/kref.h>
18#include <linux/ktime.h>
19#include <linux/list.h>
20#include <linux/spinlock.h>
21#include <linux/wait.h>
22#include <linux/fence.h>
23
24#include "uapi/sync.h"
25
26struct sync_timeline;
27struct sync_pt;
28struct sync_fence;
29
30/**
31 * struct sync_timeline_ops - sync object implementation ops
32 * @driver_name:	name of the implementation
33 * @dup:		duplicate a sync_pt
34 * @has_signaled:	returns:
35 *			  1 if pt has signaled
36 *			  0 if pt has not signaled
37 *			 <0 on error
38 * @compare:		returns:
39 *			  1 if b will signal before a
40 *			  0 if a and b will signal at the same time
41 *			 -1 if a will signal before b
42 * @free_pt:		called before sync_pt is freed
43 * @release_obj:	called before sync_timeline is freed
44 * @fill_driver_data:	write implementation specific driver data to data.
45 *			  should return an error if there is not enough room
46 *			  as specified by size.  This information is returned
47 *			  to userspace by SYNC_IOC_FENCE_INFO.
48 * @timeline_value_str: fill str with the value of the sync_timeline's counter
49 * @pt_value_str:	fill str with the value of the sync_pt
50 */
51struct sync_timeline_ops {
52	const char *driver_name;
53
54	/* required */
55	struct sync_pt * (*dup)(struct sync_pt *pt);
56
57	/* required */
58	int (*has_signaled)(struct sync_pt *pt);
59
60	/* required */
61	int (*compare)(struct sync_pt *a, struct sync_pt *b);
62
63	/* optional */
64	void (*free_pt)(struct sync_pt *sync_pt);
65
66	/* optional */
67	void (*release_obj)(struct sync_timeline *sync_timeline);
68
69	/* optional */
70	int (*fill_driver_data)(struct sync_pt *syncpt, void *data, int size);
71
72	/* optional */
73	void (*timeline_value_str)(struct sync_timeline *timeline, char *str,
74				   int size);
75
76	/* optional */
77	void (*pt_value_str)(struct sync_pt *pt, char *str, int size);
78};
79
80/**
81 * struct sync_timeline - sync object
82 * @kref:		reference count on fence.
83 * @ops:		ops that define the implementation of the sync_timeline
84 * @name:		name of the sync_timeline. Useful for debugging
85 * @destroyed:		set when sync_timeline is destroyed
86 * @child_list_head:	list of children sync_pts for this sync_timeline
87 * @child_list_lock:	lock protecting @child_list_head, destroyed, and
88 *			  sync_pt.status
89 * @active_list_head:	list of active (unsignaled/errored) sync_pts
90 * @sync_timeline_list:	membership in global sync_timeline_list
91 */
92struct sync_timeline {
93	struct kref		kref;
94	const struct sync_timeline_ops	*ops;
95	char			name[32];
96
97	/* protected by child_list_lock */
98	bool			destroyed;
99	int			context, value;
100
101	struct list_head	child_list_head;
102	spinlock_t		child_list_lock;
103
104	struct list_head	active_list_head;
105
106#ifdef CONFIG_DEBUG_FS
107	struct list_head	sync_timeline_list;
108#endif
109};
110
111/**
112 * struct sync_pt - sync point
113 * @fence:		base fence class
114 * @child_list:		membership in sync_timeline.child_list_head
115 * @active_list:	membership in sync_timeline.active_list_head
116 * @signaled_list:	membership in temporary signaled_list on stack
117 * @fence:		sync_fence to which the sync_pt belongs
118 * @pt_list:		membership in sync_fence.pt_list_head
119 * @status:		1: signaled, 0:active, <0: error
120 * @timestamp:		time which sync_pt status transitioned from active to
121 *			  signaled or error.
122 */
123struct sync_pt {
124	struct fence base;
125
126	struct list_head	child_list;
127	struct list_head	active_list;
128};
129
130static inline struct sync_timeline *sync_pt_parent(struct sync_pt *pt)
131{
132	return container_of(pt->base.lock, struct sync_timeline,
133			    child_list_lock);
134}
135
136struct sync_fence_cb {
137	struct fence_cb cb;
138	struct fence *sync_pt;
139	struct sync_fence *fence;
140};
141
142/**
143 * struct sync_fence - sync fence
144 * @file:		file representing this fence
145 * @kref:		reference count on fence.
146 * @name:		name of sync_fence.  Useful for debugging
147 * @pt_list_head:	list of sync_pts in the fence.  immutable once fence
148 *			  is created
149 * @status:		0: signaled, >0:active, <0: error
150 *
151 * @wq:			wait queue for fence signaling
152 * @sync_fence_list:	membership in global fence list
153 */
154struct sync_fence {
155	struct file		*file;
156	struct kref		kref;
157	char			name[32];
158#ifdef CONFIG_DEBUG_FS
159	struct list_head	sync_fence_list;
160#endif
161	int num_fences;
162
163	wait_queue_head_t	wq;
164	atomic_t		status;
165
166	struct sync_fence_cb	cbs[];
167};
168
169struct sync_fence_waiter;
170typedef void (*sync_callback_t)(struct sync_fence *fence,
171				struct sync_fence_waiter *waiter);
172
173/**
174 * struct sync_fence_waiter - metadata for asynchronous waiter on a fence
175 * @waiter_list:	membership in sync_fence.waiter_list_head
176 * @callback:		function pointer to call when fence signals
177 * @callback_data:	pointer to pass to @callback
178 */
179struct sync_fence_waiter {
180	wait_queue_t work;
181	sync_callback_t callback;
182};
183
184static inline void sync_fence_waiter_init(struct sync_fence_waiter *waiter,
185					  sync_callback_t callback)
186{
187	INIT_LIST_HEAD(&waiter->work.task_list);
188	waiter->callback = callback;
189}
190
191/*
192 * API for sync_timeline implementers
193 */
194
195/**
196 * sync_timeline_create() - creates a sync object
197 * @ops:	specifies the implementation ops for the object
198 * @size:	size to allocate for this obj
199 * @name:	sync_timeline name
200 *
201 * Creates a new sync_timeline which will use the implementation specified by
202 * @ops.  @size bytes will be allocated allowing for implementation specific
203 * data to be kept after the generic sync_timeline struct.
204 */
205struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
206					   int size, const char *name);
207
208/**
209 * sync_timeline_destroy() - destroys a sync object
210 * @obj:	sync_timeline to destroy
211 *
212 * A sync implementation should call this when the @obj is going away
213 * (i.e. module unload.)  @obj won't actually be freed until all its children
214 * sync_pts are freed.
215 */
216void sync_timeline_destroy(struct sync_timeline *obj);
217
218/**
219 * sync_timeline_signal() - signal a status change on a sync_timeline
220 * @obj:	sync_timeline to signal
221 *
222 * A sync implementation should call this any time one of it's sync_pts
223 * has signaled or has an error condition.
224 */
225void sync_timeline_signal(struct sync_timeline *obj);
226
227/**
228 * sync_pt_create() - creates a sync pt
229 * @parent:	sync_pt's parent sync_timeline
230 * @size:	size to allocate for this pt
231 *
232 * Creates a new sync_pt as a child of @parent.  @size bytes will be
233 * allocated allowing for implementation specific data to be kept after
234 * the generic sync_timeline struct.
235 */
236struct sync_pt *sync_pt_create(struct sync_timeline *parent, int size);
237
238/**
239 * sync_pt_free() - frees a sync pt
240 * @pt:		sync_pt to free
241 *
242 * This should only be called on sync_pts which have been created but
243 * not added to a fence.
244 */
245void sync_pt_free(struct sync_pt *pt);
246
247/**
248 * sync_fence_create() - creates a sync fence
249 * @name:	name of fence to create
250 * @pt:		sync_pt to add to the fence
251 *
252 * Creates a fence containg @pt.  Once this is called, the fence takes
253 * ownership of @pt.
254 */
255struct sync_fence *sync_fence_create(const char *name, struct sync_pt *pt);
256
257/*
258 * API for sync_fence consumers
259 */
260
261/**
262 * sync_fence_merge() - merge two fences
263 * @name:	name of new fence
264 * @a:		fence a
265 * @b:		fence b
266 *
267 * Creates a new fence which contains copies of all the sync_pts in both
268 * @a and @b.  @a and @b remain valid, independent fences.
269 */
270struct sync_fence *sync_fence_merge(const char *name,
271				    struct sync_fence *a, struct sync_fence *b);
272
273/**
274 * sync_fence_fdget() - get a fence from an fd
275 * @fd:		fd referencing a fence
276 *
277 * Ensures @fd references a valid fence, increments the refcount of the backing
278 * file, and returns the fence.
279 */
280struct sync_fence *sync_fence_fdget(int fd);
281
282/**
283 * sync_fence_put() - puts a reference of a sync fence
284 * @fence:	fence to put
285 *
286 * Puts a reference on @fence.  If this is the last reference, the fence and
287 * all it's sync_pts will be freed
288 */
289void sync_fence_put(struct sync_fence *fence);
290
291/**
292 * sync_fence_install() - installs a fence into a file descriptor
293 * @fence:	fence to install
294 * @fd:		file descriptor in which to install the fence
295 *
296 * Installs @fence into @fd.  @fd's should be acquired through
297 * get_unused_fd_flags(O_CLOEXEC).
298 */
299void sync_fence_install(struct sync_fence *fence, int fd);
300
301/**
302 * sync_fence_wait_async() - registers and async wait on the fence
303 * @fence:		fence to wait on
304 * @waiter:		waiter callback struck
305 *
306 * Returns 1 if @fence has already signaled.
307 *
308 * Registers a callback to be called when @fence signals or has an error.
309 * @waiter should be initialized with sync_fence_waiter_init().
310 */
311int sync_fence_wait_async(struct sync_fence *fence,
312			  struct sync_fence_waiter *waiter);
313
314/**
315 * sync_fence_cancel_async() - cancels an async wait
316 * @fence:		fence to wait on
317 * @waiter:		waiter callback struck
318 *
319 * returns 0 if waiter was removed from fence's async waiter list.
320 * returns -ENOENT if waiter was not found on fence's async waiter list.
321 *
322 * Cancels a previously registered async wait.  Will fail gracefully if
323 * @waiter was never registered or if @fence has already signaled @waiter.
324 */
325int sync_fence_cancel_async(struct sync_fence *fence,
326			    struct sync_fence_waiter *waiter);
327
328/**
329 * sync_fence_wait() - wait on fence
330 * @fence:	fence to wait on
331 * @tiemout:	timeout in ms
332 *
333 * Wait for @fence to be signaled or have an error.  Waits indefinitely
334 * if @timeout < 0
335 */
336int sync_fence_wait(struct sync_fence *fence, long timeout);
337
338#ifdef CONFIG_DEBUG_FS
339
340extern void sync_timeline_debug_add(struct sync_timeline *obj);
341extern void sync_timeline_debug_remove(struct sync_timeline *obj);
342extern void sync_fence_debug_add(struct sync_fence *fence);
343extern void sync_fence_debug_remove(struct sync_fence *fence);
344extern void sync_dump(void);
345
346#else
347# define sync_timeline_debug_add(obj)
348# define sync_timeline_debug_remove(obj)
349# define sync_fence_debug_add(fence)
350# define sync_fence_debug_remove(fence)
351# define sync_dump()
352#endif
353int sync_fence_wake_up_wq(wait_queue_t *curr, unsigned mode,
354				 int wake_flags, void *key);
355
356#endif /* _LINUX_SYNC_H */
357