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
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 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 */
51 struct 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 */
92 struct 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 */
123 struct sync_pt {
124 struct fence base;
125
126 struct list_head child_list;
127 struct list_head active_list;
128 };
129
sync_pt_parent(struct sync_pt * pt)130 static 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
136 struct 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 */
154 struct 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
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 wait_queue_t work;
181 sync_callback_t callback;
182 };
183
sync_fence_waiter_init(struct sync_fence_waiter * waiter,sync_callback_t callback)184 static 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 */
205 struct 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 */
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 implementation 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 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 */
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 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 */
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 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 */
299 void 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 */
311 int 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 */
325 int 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 */
336 int sync_fence_wait(struct sync_fence *fence, long timeout);
337
338 #ifdef CONFIG_DEBUG_FS
339
340 extern void sync_timeline_debug_add(struct sync_timeline *obj);
341 extern void sync_timeline_debug_remove(struct sync_timeline *obj);
342 extern void sync_fence_debug_add(struct sync_fence *fence);
343 extern void sync_fence_debug_remove(struct sync_fence *fence);
344 extern 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
353 int sync_fence_wake_up_wq(wait_queue_t *curr, unsigned mode,
354 int wake_flags, void *key);
355
356 #endif /* _LINUX_SYNC_H */
357