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 #ifdef __KERNEL__
18
19 #include <linux/kref.h>
20 #include <linux/ktime.h>
21 #include <linux/list.h>
22 #include <linux/seq_file.h>
23 #include <linux/spinlock.h>
24 #include <linux/wait.h>
25
26 struct sync_timeline;
27 struct sync_pt;
28 struct sync_fence;
29
30 /**
31 * struct sync_timeline_ops - sync object implementation ops
32 * @driver_name: name of the implentation
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 signabl before b
42 * @free_pt: called before sync_pt is freed
43 * @release_obj: called before sync_timeline is freed
44 * @print_obj: deprecated
45 * @print_pt: deprecated
46 * @fill_driver_data: write implmentation specific driver data to data.
47 * should return an error if there is not enough room
48 * as specified by size. This information is returned
49 * to userspace by SYNC_IOC_FENCE_INFO.
50 * @timeline_value_str: fill str with the value of the sync_timeline's counter
51 * @pt_value_str: fill str with the value of the sync_pt
52 */
53 struct sync_timeline_ops {
54 const char *driver_name;
55
56 /* required */
57 struct sync_pt *(*dup)(struct sync_pt *pt);
58
59 /* required */
60 int (*has_signaled)(struct sync_pt *pt);
61
62 /* required */
63 int (*compare)(struct sync_pt *a, struct sync_pt *b);
64
65 /* optional */
66 void (*free_pt)(struct sync_pt *sync_pt);
67
68 /* optional */
69 void (*release_obj)(struct sync_timeline *sync_timeline);
70
71 /* deprecated */
72 void (*print_obj)(struct seq_file *s,
73 struct sync_timeline *sync_timeline);
74
75 /* deprecated */
76 void (*print_pt)(struct seq_file *s, struct sync_pt *sync_pt);
77
78 /* optional */
79 int (*fill_driver_data)(struct sync_pt *syncpt, void *data, int size);
80
81 /* optional */
82 void (*timeline_value_str)(struct sync_timeline *timeline, char *str,
83 int size);
84
85 /* optional */
86 void (*pt_value_str)(struct sync_pt *pt, char *str, int size);
87 };
88
89 /**
90 * struct sync_timeline - sync object
91 * @kref: reference count on fence.
92 * @ops: ops that define the implementaiton of the sync_timeline
93 * @name: name of the sync_timeline. Useful for debugging
94 * @destoryed: set when sync_timeline is destroyed
95 * @child_list_head: list of children sync_pts for this sync_timeline
96 * @child_list_lock: lock protecting @child_list_head, destroyed, and
97 * sync_pt.status
98 * @active_list_head: list of active (unsignaled/errored) sync_pts
99 * @sync_timeline_list: membership in global sync_timeline_list
100 */
101 struct sync_timeline {
102 struct kref kref;
103 const struct sync_timeline_ops *ops;
104 char name[32];
105
106 /* protected by child_list_lock */
107 bool destroyed;
108
109 struct list_head child_list_head;
110 spinlock_t child_list_lock;
111
112 struct list_head active_list_head;
113 spinlock_t active_list_lock;
114
115 struct list_head sync_timeline_list;
116 };
117
118 /**
119 * struct sync_pt - sync point
120 * @parent: sync_timeline to which this sync_pt belongs
121 * @child_list: membership in sync_timeline.child_list_head
122 * @active_list: membership in sync_timeline.active_list_head
123 * @signaled_list: membership in temorary signaled_list on stack
124 * @fence: sync_fence to which the sync_pt belongs
125 * @pt_list: membership in sync_fence.pt_list_head
126 * @status: 1: signaled, 0:active, <0: error
127 * @timestamp: time which sync_pt status transitioned from active to
128 * singaled or error.
129 */
130 struct sync_pt {
131 struct sync_timeline *parent;
132 struct list_head child_list;
133
134 struct list_head active_list;
135 struct list_head signaled_list;
136
137 struct sync_fence *fence;
138 struct list_head pt_list;
139
140 /* protected by parent->active_list_lock */
141 int status;
142
143 ktime_t timestamp;
144 };
145
146 /**
147 * struct sync_fence - sync fence
148 * @file: file representing this fence
149 * @kref: referenace count on fence.
150 * @name: name of sync_fence. Useful for debugging
151 * @pt_list_head: list of sync_pts in ths fence. immutable once fence
152 * is created
153 * @waiter_list_head: list of asynchronous waiters on this fence
154 * @waiter_list_lock: lock protecting @waiter_list_head and @status
155 * @status: 1: signaled, 0:active, <0: error
156 *
157 * @wq: wait queue for fence signaling
158 * @sync_fence_list: membership in global fence list
159 */
160 struct sync_fence {
161 struct file *file;
162 struct kref kref;
163 char name[32];
164
165 /* this list is immutable once the fence is created */
166 struct list_head pt_list_head;
167
168 struct list_head waiter_list_head;
169 spinlock_t waiter_list_lock; /* also protects status */
170 int status;
171
172 wait_queue_head_t wq;
173
174 struct list_head sync_fence_list;
175 };
176
177 struct sync_fence_waiter;
178 typedef void (*sync_callback_t)(struct sync_fence *fence,
179 struct sync_fence_waiter *waiter);
180
181 /**
182 * struct sync_fence_waiter - metadata for asynchronous waiter on a fence
183 * @waiter_list: membership in sync_fence.waiter_list_head
184 * @callback: function pointer to call when fence signals
185 * @callback_data: pointer to pass to @callback
186 */
187 struct sync_fence_waiter {
188 struct list_head waiter_list;
189
190 sync_callback_t callback;
191 };
192
sync_fence_waiter_init(struct sync_fence_waiter * waiter,sync_callback_t callback)193 static inline void sync_fence_waiter_init(struct sync_fence_waiter *waiter,
194 sync_callback_t callback)
195 {
196 waiter->callback = callback;
197 }
198
199 /*
200 * API for sync_timeline implementers
201 */
202
203 /**
204 * sync_timeline_create() - creates a sync object
205 * @ops: specifies the implemention ops for the object
206 * @size: size to allocate for this obj
207 * @name: sync_timeline name
208 *
209 * Creates a new sync_timeline which will use the implemetation specified by
210 * @ops. @size bytes will be allocated allowing for implemntation specific
211 * data to be kept after the generic sync_timeline stuct.
212 */
213 struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
214 int size, const char *name);
215
216 /**
217 * sync_timeline_destory() - destorys a sync object
218 * @obj: sync_timeline to destroy
219 *
220 * A sync implemntation should call this when the @obj is going away
221 * (i.e. module unload.) @obj won't actually be freed until all its childern
222 * sync_pts are freed.
223 */
224 void sync_timeline_destroy(struct sync_timeline *obj);
225
226 /**
227 * sync_timeline_signal() - signal a status change on a sync_timeline
228 * @obj: sync_timeline to signal
229 *
230 * A sync implemntation should call this any time one of it's sync_pts
231 * has signaled or has an error condition.
232 */
233 void sync_timeline_signal(struct sync_timeline *obj);
234
235 /**
236 * sync_pt_create() - creates a sync pt
237 * @parent: sync_pt's parent sync_timeline
238 * @size: size to allocate for this pt
239 *
240 * Creates a new sync_pt as a chiled of @parent. @size bytes will be
241 * allocated allowing for implemntation specific data to be kept after
242 * the generic sync_timeline struct.
243 */
244 struct sync_pt *sync_pt_create(struct sync_timeline *parent, int size);
245
246 /**
247 * sync_pt_free() - frees a sync pt
248 * @pt: sync_pt to free
249 *
250 * This should only be called on sync_pts which have been created but
251 * not added to a fence.
252 */
253 void sync_pt_free(struct sync_pt *pt);
254
255 /**
256 * sync_fence_create() - creates a sync fence
257 * @name: name of fence to create
258 * @pt: sync_pt to add to the fence
259 *
260 * Creates a fence containg @pt. Once this is called, the fence takes
261 * ownership of @pt.
262 */
263 struct sync_fence *sync_fence_create(const char *name, struct sync_pt *pt);
264
265 /*
266 * API for sync_fence consumers
267 */
268
269 /**
270 * sync_fence_merge() - merge two fences
271 * @name: name of new fence
272 * @a: fence a
273 * @b: fence b
274 *
275 * Creates a new fence which contains copies of all the sync_pts in both
276 * @a and @b. @a and @b remain valid, independent fences.
277 */
278 struct sync_fence *sync_fence_merge(const char *name,
279 struct sync_fence *a, struct sync_fence *b);
280
281 /**
282 * sync_fence_fdget() - get a fence from an fd
283 * @fd: fd referencing a fence
284 *
285 * Ensures @fd references a valid fence, increments the refcount of the backing
286 * file, and returns the fence.
287 */
288 struct sync_fence *sync_fence_fdget(int fd);
289
290 /**
291 * sync_fence_put() - puts a refernnce of a sync fence
292 * @fence: fence to put
293 *
294 * Puts a reference on @fence. If this is the last reference, the fence and
295 * all it's sync_pts will be freed
296 */
297 void sync_fence_put(struct sync_fence *fence);
298
299 /**
300 * sync_fence_install() - installs a fence into a file descriptor
301 * @fence: fence to instal
302 * @fd: file descriptor in which to install the fence
303 *
304 * Installs @fence into @fd. @fd's should be acquired through get_unused_fd().
305 */
306 void sync_fence_install(struct sync_fence *fence, int fd);
307
308 /**
309 * sync_fence_wait_async() - registers and async wait on the fence
310 * @fence: fence to wait on
311 * @waiter: waiter callback struck
312 *
313 * Returns 1 if @fence has already signaled.
314 *
315 * Registers a callback to be called when @fence signals or has an error.
316 * @waiter should be initialized with sync_fence_waiter_init().
317 */
318 int sync_fence_wait_async(struct sync_fence *fence,
319 struct sync_fence_waiter *waiter);
320
321 /**
322 * sync_fence_cancel_async() - cancels an async wait
323 * @fence: fence to wait on
324 * @waiter: waiter callback struck
325 *
326 * returns 0 if waiter was removed from fence's async waiter list.
327 * returns -ENOENT if waiter was not found on fence's async waiter list.
328 *
329 * Cancels a previously registered async wait. Will fail gracefully if
330 * @waiter was never registered or if @fence has already signaled @waiter.
331 */
332 int sync_fence_cancel_async(struct sync_fence *fence,
333 struct sync_fence_waiter *waiter);
334
335 /**
336 * sync_fence_wait() - wait on fence
337 * @fence: fence to wait on
338 * @tiemout: timeout in ms
339 *
340 * Wait for @fence to be signaled or have an error. Waits indefinitely
341 * if @timeout < 0
342 */
343 int sync_fence_wait(struct sync_fence *fence, long timeout);
344
345 #endif /* __KERNEL__ */
346
347 /**
348 * struct sync_merge_data - data passed to merge ioctl
349 * @fd2: file descriptor of second fence
350 * @name: name of new fence
351 * @fence: returns the fd of the new fence to userspace
352 */
353 struct sync_merge_data {
354 __s32 fd2; /* fd of second fence */
355 char name[32]; /* name of new fence */
356 __s32 fence; /* fd on newly created fence */
357 };
358
359 /**
360 * struct sync_pt_info - detailed sync_pt information
361 * @len: length of sync_pt_info including any driver_data
362 * @obj_name: name of parent sync_timeline
363 * @driver_name: name of driver implmenting the parent
364 * @status: status of the sync_pt 0:active 1:signaled <0:error
365 * @timestamp_ns: timestamp of status change in nanoseconds
366 * @driver_data: any driver dependant data
367 */
368 struct sync_pt_info {
369 __u32 len;
370 char obj_name[32];
371 char driver_name[32];
372 __s32 status;
373 __u64 timestamp_ns;
374
375 __u8 driver_data[0];
376 };
377
378 /**
379 * struct sync_fence_info_data - data returned from fence info ioctl
380 * @len: ioctl caller writes the size of the buffer its passing in.
381 * ioctl returns length of sync_fence_data reutnred to userspace
382 * including pt_info.
383 * @name: name of fence
384 * @status: status of fence. 1: signaled 0:active <0:error
385 * @pt_info: a sync_pt_info struct for every sync_pt in the fence
386 */
387 struct sync_fence_info_data {
388 __u32 len;
389 char name[32];
390 __s32 status;
391
392 __u8 pt_info[0];
393 };
394
395 #define SYNC_IOC_MAGIC '>'
396
397 /**
398 * DOC: SYNC_IOC_WAIT - wait for a fence to signal
399 *
400 * pass timeout in milliseconds. Waits indefinitely timeout < 0.
401 */
402 #define SYNC_IOC_WAIT _IOW(SYNC_IOC_MAGIC, 0, __s32)
403
404 /**
405 * DOC: SYNC_IOC_MERGE - merge two fences
406 *
407 * Takes a struct sync_merge_data. Creates a new fence containing copies of
408 * the sync_pts in both the calling fd and sync_merge_data.fd2. Returns the
409 * new fence's fd in sync_merge_data.fence
410 */
411 #define SYNC_IOC_MERGE _IOWR(SYNC_IOC_MAGIC, 1, struct sync_merge_data)
412
413 /**
414 * DOC: SYNC_IOC_FENCE_INFO - get detailed information on a fence
415 *
416 * Takes a struct sync_fence_info_data with extra space allocated for pt_info.
417 * Caller should write the size of the buffer into len. On return, len is
418 * updated to reflect the total size of the sync_fence_info_data including
419 * pt_info.
420 *
421 * pt_info is a buffer containing sync_pt_infos for every sync_pt in the fence.
422 * To itterate over the sync_pt_infos, use the sync_pt_info.len field.
423 */
424 #define SYNC_IOC_FENCE_INFO _IOWR(SYNC_IOC_MAGIC, 2,\
425 struct sync_fence_info_data)
426
427 #endif /* _LINUX_SYNC_H */
428