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/spinlock.h>
23 #include <linux/wait.h>
24
25 struct sync_timeline;
26 struct sync_pt;
27 struct sync_fence;
28
29 /**
30 * struct sync_timeline_ops - sync object implementation ops
31 * @driver_name: name of the implentation
32 * @dup: duplicate a sync_pt
33 * @has_signaled: returns:
34 * 1 if pt has signaled
35 * 0 if pt has not signaled
36 * <0 on error
37 * @compare: returns:
38 * 1 if b will signal before a
39 * 0 if a and b will signal at the same time
40 * -1 if a will signabl before b
41 * @free_pt: called before sync_pt is freed
42 * @release_obj: called before sync_timeline is freed
43 * @print_obj: print aditional debug information about sync_timeline.
44 * should not print a newline
45 * @print_pt: print aditional debug information about sync_pt.
46 * should not print a newline
47 * @fill_driver_data: write implmentation specific driver data to data.
48 * should return an error if there is not enough room
49 * as specified by size. This information is returned
50 * to userspace by SYNC_IOC_FENCE_INFO.
51 */
52 struct sync_timeline_ops {
53 const char *driver_name;
54
55 /* required */
56 struct sync_pt *(*dup)(struct sync_pt *pt);
57
58 /* required */
59 int (*has_signaled)(struct sync_pt *pt);
60
61 /* required */
62 int (*compare)(struct sync_pt *a, struct sync_pt *b);
63
64 /* optional */
65 void (*free_pt)(struct sync_pt *sync_pt);
66
67 /* optional */
68 void (*release_obj)(struct sync_timeline *sync_timeline);
69
70 /* optional */
71 void (*print_obj)(struct seq_file *s,
72 struct sync_timeline *sync_timeline);
73
74 /* optional */
75 void (*print_pt)(struct seq_file *s, struct sync_pt *sync_pt);
76
77 /* optional */
78 int (*fill_driver_data)(struct sync_pt *syncpt, void *data, int size);
79 };
80
81 /**
82 * struct sync_timeline - sync object
83 * @kref: reference count on fence.
84 * @ops: ops that define the implementaiton of the sync_timeline
85 * @name: name of the sync_timeline. Useful for debugging
86 * @destoryed: set when sync_timeline is destroyed
87 * @child_list_head: list of children sync_pts for this sync_timeline
88 * @child_list_lock: lock protecting @child_list_head, destroyed, and
89 * sync_pt.status
90 * @active_list_head: list of active (unsignaled/errored) sync_pts
91 * @sync_timeline_list: membership in global sync_timeline_list
92 */
93 struct sync_timeline {
94 struct kref kref;
95 const struct sync_timeline_ops *ops;
96 char name[32];
97
98 /* protected by child_list_lock */
99 bool destroyed;
100
101 struct list_head child_list_head;
102 spinlock_t child_list_lock;
103
104 struct list_head active_list_head;
105 spinlock_t active_list_lock;
106
107 struct list_head sync_timeline_list;
108 };
109
110 /**
111 * struct sync_pt - sync point
112 * @parent: sync_timeline to which this sync_pt belongs
113 * @child_list: membership in sync_timeline.child_list_head
114 * @active_list: membership in sync_timeline.active_list_head
115 * @signaled_list: membership in temorary signaled_list on stack
116 * @fence: sync_fence to which the sync_pt belongs
117 * @pt_list: membership in sync_fence.pt_list_head
118 * @status: 1: signaled, 0:active, <0: error
119 * @timestamp: time which sync_pt status transitioned from active to
120 * singaled or error.
121 */
122 struct sync_pt {
123 struct sync_timeline *parent;
124 struct list_head child_list;
125
126 struct list_head active_list;
127 struct list_head signaled_list;
128
129 struct sync_fence *fence;
130 struct list_head pt_list;
131
132 /* protected by parent->active_list_lock */
133 int status;
134
135 ktime_t timestamp;
136 };
137
138 /**
139 * struct sync_fence - sync fence
140 * @file: file representing this fence
141 * @kref: referenace count on fence.
142 * @name: name of sync_fence. Useful for debugging
143 * @pt_list_head: list of sync_pts in ths fence. immutable once fence
144 * is created
145 * @waiter_list_head: list of asynchronous waiters on this fence
146 * @waiter_list_lock: lock protecting @waiter_list_head and @status
147 * @status: 1: signaled, 0:active, <0: error
148 *
149 * @wq: wait queue for fence signaling
150 * @sync_fence_list: membership in global fence list
151 */
152 struct sync_fence {
153 struct file *file;
154 struct kref kref;
155 char name[32];
156
157 /* this list is immutable once the fence is created */
158 struct list_head pt_list_head;
159
160 struct list_head waiter_list_head;
161 spinlock_t waiter_list_lock; /* also protects status */
162 int status;
163
164 wait_queue_head_t wq;
165
166 struct list_head sync_fence_list;
167 };
168
169 struct sync_fence_waiter;
170 typedef 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 */
179 struct sync_fence_waiter {
180 struct list_head waiter_list;
181
182 sync_callback_t callback;
183 };
184
sync_fence_waiter_init(struct sync_fence_waiter * waiter,sync_callback_t callback)185 static inline void sync_fence_waiter_init(struct sync_fence_waiter *waiter,
186 sync_callback_t callback)
187 {
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 implemention 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 implemetation specified by
202 * @ops. @size bytes will be allocated allowing for implemntation specific
203 * data to be kept after the generic sync_timeline stuct.
204 */
205 struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
206 int size, const char *name);
207
208 /**
209 * sync_timeline_destory() - destorys a sync object
210 * @obj: sync_timeline to destroy
211 *
212 * A sync implemntation should call this when the @obj is going away
213 * (i.e. module unload.) @obj won't actually be freed until all its childern
214 * sync_pts are freed.
215 */
216 void 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 implemntation should call this any time one of it's sync_pts
223 * has signaled or has an error condition.
224 */
225 void 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 chiled of @parent. @size bytes will be
233 * allocated allowing for implemntation specific data to be kept after
234 * the generic sync_timeline struct.
235 */
236 struct 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 */
245 void 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 */
255 struct 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 */
270 struct 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 */
280 struct sync_fence *sync_fence_fdget(int fd);
281
282 /**
283 * sync_fence_put() - puts a refernnce 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 */
289 void sync_fence_put(struct sync_fence *fence);
290
291 /**
292 * sync_fence_install() - installs a fence into a file descriptor
293 * @fence: fence to instal
294 * @fd: file descriptor in which to install the fence
295 *
296 * Installs @fence into @fd. @fd's should be acquired through get_unused_fd().
297 */
298 void sync_fence_install(struct sync_fence *fence, int fd);
299
300 /**
301 * sync_fence_wait_async() - registers and async wait on the fence
302 * @fence: fence to wait on
303 * @waiter: waiter callback struck
304 *
305 * Returns 1 if @fence has already signaled.
306 *
307 * Registers a callback to be called when @fence signals or has an error.
308 * @waiter should be initialized with sync_fence_waiter_init().
309 */
310 int sync_fence_wait_async(struct sync_fence *fence,
311 struct sync_fence_waiter *waiter);
312
313 /**
314 * sync_fence_cancel_async() - cancels an async wait
315 * @fence: fence to wait on
316 * @waiter: waiter callback struck
317 *
318 * returns 0 if waiter was removed from fence's async waiter list.
319 * returns -ENOENT if waiter was not found on fence's async waiter list.
320 *
321 * Cancels a previously registered async wait. Will fail gracefully if
322 * @waiter was never registered or if @fence has already signaled @waiter.
323 */
324 int sync_fence_cancel_async(struct sync_fence *fence,
325 struct sync_fence_waiter *waiter);
326
327 /**
328 * sync_fence_wait() - wait on fence
329 * @fence: fence to wait on
330 * @tiemout: timeout in ms
331 *
332 * Wait for @fence to be signaled or have an error. Waits indefinitely
333 * if @timeout < 0
334 */
335 int sync_fence_wait(struct sync_fence *fence, long timeout);
336
337 #endif /* __KERNEL__ */
338
339 /**
340 * struct sync_merge_data - data passed to merge ioctl
341 * @fd2: file descriptor of second fence
342 * @name: name of new fence
343 * @fence: returns the fd of the new fence to userspace
344 */
345 struct sync_merge_data {
346 __s32 fd2; /* fd of second fence */
347 char name[32]; /* name of new fence */
348 __s32 fence; /* fd on newly created fence */
349 };
350
351 /**
352 * struct sync_pt_info - detailed sync_pt information
353 * @len: length of sync_pt_info including any driver_data
354 * @obj_name: name of parent sync_timeline
355 * @driver_name: name of driver implmenting the parent
356 * @status: status of the sync_pt 0:active 1:signaled <0:error
357 * @timestamp_ns: timestamp of status change in nanoseconds
358 * @driver_data: any driver dependant data
359 */
360 struct sync_pt_info {
361 __u32 len;
362 char obj_name[32];
363 char driver_name[32];
364 __s32 status;
365 __u64 timestamp_ns;
366
367 __u8 driver_data[0];
368 };
369
370 /**
371 * struct sync_fence_info_data - data returned from fence info ioctl
372 * @len: ioctl caller writes the size of the buffer its passing in.
373 * ioctl returns length of sync_fence_data reutnred to userspace
374 * including pt_info.
375 * @name: name of fence
376 * @status: status of fence. 1: signaled 0:active <0:error
377 * @pt_info: a sync_pt_info struct for every sync_pt in the fence
378 */
379 struct sync_fence_info_data {
380 __u32 len;
381 char name[32];
382 __s32 status;
383
384 __u8 pt_info[0];
385 };
386
387 #define SYNC_IOC_MAGIC '>'
388
389 /**
390 * DOC: SYNC_IOC_WAIT - wait for a fence to signal
391 *
392 * pass timeout in milliseconds. Waits indefinitely timeout < 0.
393 */
394 #define SYNC_IOC_WAIT _IOW(SYNC_IOC_MAGIC, 0, __s32)
395
396 /**
397 * DOC: SYNC_IOC_MERGE - merge two fences
398 *
399 * Takes a struct sync_merge_data. Creates a new fence containing copies of
400 * the sync_pts in both the calling fd and sync_merge_data.fd2. Returns the
401 * new fence's fd in sync_merge_data.fence
402 */
403 #define SYNC_IOC_MERGE _IOWR(SYNC_IOC_MAGIC, 1, struct sync_merge_data)
404
405 /**
406 * DOC: SYNC_IOC_FENCE_INFO - get detailed information on a fence
407 *
408 * Takes a struct sync_fence_info_data with extra space allocated for pt_info.
409 * Caller should write the size of the buffer into len. On return, len is
410 * updated to reflect the total size of the sync_fence_info_data including
411 * pt_info.
412 *
413 * pt_info is a buffer containing sync_pt_infos for every sync_pt in the fence.
414 * To itterate over the sync_pt_infos, use the sync_pt_info.len field.
415 */
416 #define SYNC_IOC_FENCE_INFO _IOWR(SYNC_IOC_MAGIC, 2,\
417 struct sync_fence_info_data)
418
419 #endif /* _LINUX_SYNC_H */
420