1 /*
2 * v4l2-event.c
3 *
4 * V4L2 events.
5 *
6 * Copyright (C) 2009--2010 Nokia Corporation.
7 *
8 * Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * version 2 as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22 * 02110-1301 USA
23 */
24
25 #include <media/v4l2-dev.h>
26 #include <media/v4l2-fh.h>
27 #include <media/v4l2-event.h>
28
29 #include <linux/sched.h>
30 #include <linux/slab.h>
31
v4l2_event_init(struct v4l2_fh * fh)32 int v4l2_event_init(struct v4l2_fh *fh)
33 {
34 fh->events = kzalloc(sizeof(*fh->events), GFP_KERNEL);
35 if (fh->events == NULL)
36 return -ENOMEM;
37
38 init_waitqueue_head(&fh->events->wait);
39
40 INIT_LIST_HEAD(&fh->events->free);
41 INIT_LIST_HEAD(&fh->events->available);
42 INIT_LIST_HEAD(&fh->events->subscribed);
43
44 fh->events->sequence = -1;
45
46 return 0;
47 }
48 EXPORT_SYMBOL_GPL(v4l2_event_init);
49
v4l2_event_alloc(struct v4l2_fh * fh,unsigned int n)50 int v4l2_event_alloc(struct v4l2_fh *fh, unsigned int n)
51 {
52 struct v4l2_events *events = fh->events;
53 unsigned long flags;
54
55 if (!events) {
56 WARN_ON(1);
57 return -ENOMEM;
58 }
59
60 while (events->nallocated < n) {
61 struct v4l2_kevent *kev;
62
63 kev = kzalloc(sizeof(*kev), GFP_KERNEL);
64 if (kev == NULL)
65 return -ENOMEM;
66
67 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
68 list_add_tail(&kev->list, &events->free);
69 events->nallocated++;
70 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
71 }
72
73 return 0;
74 }
75 EXPORT_SYMBOL_GPL(v4l2_event_alloc);
76
77 #define list_kfree(list, type, member) \
78 while (!list_empty(list)) { \
79 type *hi; \
80 hi = list_first_entry(list, type, member); \
81 list_del(&hi->member); \
82 kfree(hi); \
83 }
84
v4l2_event_free(struct v4l2_fh * fh)85 void v4l2_event_free(struct v4l2_fh *fh)
86 {
87 struct v4l2_events *events = fh->events;
88
89 if (!events)
90 return;
91
92 list_kfree(&events->free, struct v4l2_kevent, list);
93 list_kfree(&events->available, struct v4l2_kevent, list);
94 list_kfree(&events->subscribed, struct v4l2_subscribed_event, list);
95
96 kfree(events);
97 fh->events = NULL;
98 }
99 EXPORT_SYMBOL_GPL(v4l2_event_free);
100
__v4l2_event_dequeue(struct v4l2_fh * fh,struct v4l2_event * event)101 static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)
102 {
103 struct v4l2_events *events = fh->events;
104 struct v4l2_kevent *kev;
105 unsigned long flags;
106
107 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
108
109 if (list_empty(&events->available)) {
110 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
111 return -ENOENT;
112 }
113
114 WARN_ON(events->navailable == 0);
115
116 kev = list_first_entry(&events->available, struct v4l2_kevent, list);
117 list_move(&kev->list, &events->free);
118 events->navailable--;
119
120 kev->event.pending = events->navailable;
121 *event = kev->event;
122
123 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
124
125 return 0;
126 }
127
v4l2_event_dequeue(struct v4l2_fh * fh,struct v4l2_event * event,int nonblocking)128 int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
129 int nonblocking)
130 {
131 struct v4l2_events *events = fh->events;
132 int ret;
133
134 if (nonblocking)
135 return __v4l2_event_dequeue(fh, event);
136
137 /* Release the vdev lock while waiting */
138 if (fh->vdev->lock)
139 mutex_unlock(fh->vdev->lock);
140
141 do {
142 ret = wait_event_interruptible(events->wait,
143 events->navailable != 0);
144 if (ret < 0)
145 break;
146
147 ret = __v4l2_event_dequeue(fh, event);
148 } while (ret == -ENOENT);
149
150 if (fh->vdev->lock)
151 mutex_lock(fh->vdev->lock);
152
153 return ret;
154 }
155 EXPORT_SYMBOL_GPL(v4l2_event_dequeue);
156
157 /* Caller must hold fh->event->lock! */
v4l2_event_subscribed(struct v4l2_fh * fh,u32 type)158 static struct v4l2_subscribed_event *v4l2_event_subscribed(
159 struct v4l2_fh *fh, u32 type)
160 {
161 struct v4l2_events *events = fh->events;
162 struct v4l2_subscribed_event *sev;
163
164 assert_spin_locked(&fh->vdev->fh_lock);
165
166 list_for_each_entry(sev, &events->subscribed, list) {
167 if (sev->type == type)
168 return sev;
169 }
170
171 return NULL;
172 }
173
v4l2_event_queue(struct video_device * vdev,const struct v4l2_event * ev)174 void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev)
175 {
176 struct v4l2_fh *fh;
177 unsigned long flags;
178 struct timespec timestamp;
179
180 ktime_get_ts(×tamp);
181
182 spin_lock_irqsave(&vdev->fh_lock, flags);
183
184 list_for_each_entry(fh, &vdev->fh_list, list) {
185 struct v4l2_events *events = fh->events;
186 struct v4l2_kevent *kev;
187
188 /* Are we subscribed? */
189 if (!v4l2_event_subscribed(fh, ev->type))
190 continue;
191
192 /* Increase event sequence number on fh. */
193 events->sequence++;
194
195 /* Do we have any free events? */
196 if (list_empty(&events->free))
197 continue;
198
199 /* Take one and fill it. */
200 kev = list_first_entry(&events->free, struct v4l2_kevent, list);
201 kev->event.type = ev->type;
202 kev->event.u = ev->u;
203 kev->event.timestamp = timestamp;
204 kev->event.sequence = events->sequence;
205 list_move_tail(&kev->list, &events->available);
206
207 events->navailable++;
208
209 wake_up_all(&events->wait);
210 }
211
212 spin_unlock_irqrestore(&vdev->fh_lock, flags);
213 }
214 EXPORT_SYMBOL_GPL(v4l2_event_queue);
215
v4l2_event_pending(struct v4l2_fh * fh)216 int v4l2_event_pending(struct v4l2_fh *fh)
217 {
218 return fh->events->navailable;
219 }
220 EXPORT_SYMBOL_GPL(v4l2_event_pending);
221
v4l2_event_subscribe(struct v4l2_fh * fh,struct v4l2_event_subscription * sub)222 int v4l2_event_subscribe(struct v4l2_fh *fh,
223 struct v4l2_event_subscription *sub)
224 {
225 struct v4l2_events *events = fh->events;
226 struct v4l2_subscribed_event *sev;
227 unsigned long flags;
228
229 if (fh->events == NULL) {
230 WARN_ON(1);
231 return -ENOMEM;
232 }
233
234 sev = kmalloc(sizeof(*sev), GFP_KERNEL);
235 if (!sev)
236 return -ENOMEM;
237
238 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
239
240 if (v4l2_event_subscribed(fh, sub->type) == NULL) {
241 INIT_LIST_HEAD(&sev->list);
242 sev->type = sub->type;
243
244 list_add(&sev->list, &events->subscribed);
245 sev = NULL;
246 }
247
248 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
249
250 kfree(sev);
251
252 return 0;
253 }
254 EXPORT_SYMBOL_GPL(v4l2_event_subscribe);
255
v4l2_event_unsubscribe_all(struct v4l2_fh * fh)256 static void v4l2_event_unsubscribe_all(struct v4l2_fh *fh)
257 {
258 struct v4l2_events *events = fh->events;
259 struct v4l2_subscribed_event *sev;
260 unsigned long flags;
261
262 do {
263 sev = NULL;
264
265 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
266 if (!list_empty(&events->subscribed)) {
267 sev = list_first_entry(&events->subscribed,
268 struct v4l2_subscribed_event, list);
269 list_del(&sev->list);
270 }
271 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
272 kfree(sev);
273 } while (sev);
274 }
275
v4l2_event_unsubscribe(struct v4l2_fh * fh,struct v4l2_event_subscription * sub)276 int v4l2_event_unsubscribe(struct v4l2_fh *fh,
277 struct v4l2_event_subscription *sub)
278 {
279 struct v4l2_subscribed_event *sev;
280 unsigned long flags;
281
282 if (sub->type == V4L2_EVENT_ALL) {
283 v4l2_event_unsubscribe_all(fh);
284 return 0;
285 }
286
287 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
288
289 sev = v4l2_event_subscribed(fh, sub->type);
290 if (sev != NULL)
291 list_del(&sev->list);
292
293 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
294
295 kfree(sev);
296
297 return 0;
298 }
299 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);
300