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12#include <media/v4l2-dev.h>
13#include <media/v4l2-fh.h>
14#include <media/v4l2-event.h>
15
16#include <linux/mm.h>
17#include <linux/sched.h>
18#include <linux/slab.h>
19#include <linux/export.h>
20
21static unsigned int sev_pos(const struct v4l2_subscribed_event *sev, unsigned int idx)
22{
23 idx += sev->first;
24 return idx >= sev->elems ? idx - sev->elems : idx;
25}
26
27static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)
28{
29 struct v4l2_kevent *kev;
30 struct timespec64 ts;
31 unsigned long flags;
32
33 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
34
35 if (list_empty(&fh->available)) {
36 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
37 return -ENOENT;
38 }
39
40 WARN_ON(fh->navailable == 0);
41
42 kev = list_first_entry(&fh->available, struct v4l2_kevent, list);
43 list_del(&kev->list);
44 fh->navailable--;
45
46 kev->event.pending = fh->navailable;
47 *event = kev->event;
48 ts = ns_to_timespec64(kev->ts);
49 event->timestamp.tv_sec = ts.tv_sec;
50 event->timestamp.tv_nsec = ts.tv_nsec;
51 kev->sev->first = sev_pos(kev->sev, 1);
52 kev->sev->in_use--;
53
54 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
55
56 return 0;
57}
58
59int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
60 int nonblocking)
61{
62 int ret;
63
64 if (nonblocking)
65 return __v4l2_event_dequeue(fh, event);
66
67
68 if (fh->vdev->lock)
69 mutex_unlock(fh->vdev->lock);
70
71 do {
72 ret = wait_event_interruptible(fh->wait,
73 fh->navailable != 0);
74 if (ret < 0)
75 break;
76
77 ret = __v4l2_event_dequeue(fh, event);
78 } while (ret == -ENOENT);
79
80 if (fh->vdev->lock)
81 mutex_lock(fh->vdev->lock);
82
83 return ret;
84}
85EXPORT_SYMBOL_GPL(v4l2_event_dequeue);
86
87
88static struct v4l2_subscribed_event *v4l2_event_subscribed(
89 struct v4l2_fh *fh, u32 type, u32 id)
90{
91 struct v4l2_subscribed_event *sev;
92
93 assert_spin_locked(&fh->vdev->fh_lock);
94
95 list_for_each_entry(sev, &fh->subscribed, list)
96 if (sev->type == type && sev->id == id)
97 return sev;
98
99 return NULL;
100}
101
102static void __v4l2_event_queue_fh(struct v4l2_fh *fh,
103 const struct v4l2_event *ev, u64 ts)
104{
105 struct v4l2_subscribed_event *sev;
106 struct v4l2_kevent *kev;
107 bool copy_payload = true;
108
109
110 sev = v4l2_event_subscribed(fh, ev->type, ev->id);
111 if (sev == NULL)
112 return;
113
114
115 fh->sequence++;
116
117
118 if (sev->in_use == sev->elems) {
119
120 kev = sev->events + sev_pos(sev, 0);
121 list_del(&kev->list);
122 sev->in_use--;
123 sev->first = sev_pos(sev, 1);
124 fh->navailable--;
125 if (sev->elems == 1) {
126 if (sev->ops && sev->ops->replace) {
127 sev->ops->replace(&kev->event, ev);
128 copy_payload = false;
129 }
130 } else if (sev->ops && sev->ops->merge) {
131 struct v4l2_kevent *second_oldest =
132 sev->events + sev_pos(sev, 0);
133 sev->ops->merge(&kev->event, &second_oldest->event);
134 }
135 }
136
137
138 kev = sev->events + sev_pos(sev, sev->in_use);
139 kev->event.type = ev->type;
140 if (copy_payload)
141 kev->event.u = ev->u;
142 kev->event.id = ev->id;
143 kev->ts = ts;
144 kev->event.sequence = fh->sequence;
145 sev->in_use++;
146 list_add_tail(&kev->list, &fh->available);
147
148 fh->navailable++;
149
150 wake_up_all(&fh->wait);
151}
152
153void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev)
154{
155 struct v4l2_fh *fh;
156 unsigned long flags;
157 u64 ts;
158
159 if (vdev == NULL)
160 return;
161
162 ts = ktime_get_ns();
163
164 spin_lock_irqsave(&vdev->fh_lock, flags);
165
166 list_for_each_entry(fh, &vdev->fh_list, list)
167 __v4l2_event_queue_fh(fh, ev, ts);
168
169 spin_unlock_irqrestore(&vdev->fh_lock, flags);
170}
171EXPORT_SYMBOL_GPL(v4l2_event_queue);
172
173void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev)
174{
175 unsigned long flags;
176 u64 ts = ktime_get_ns();
177
178 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
179 __v4l2_event_queue_fh(fh, ev, ts);
180 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
181}
182EXPORT_SYMBOL_GPL(v4l2_event_queue_fh);
183
184int v4l2_event_pending(struct v4l2_fh *fh)
185{
186 return fh->navailable;
187}
188EXPORT_SYMBOL_GPL(v4l2_event_pending);
189
190void v4l2_event_wake_all(struct video_device *vdev)
191{
192 struct v4l2_fh *fh;
193 unsigned long flags;
194
195 if (!vdev)
196 return;
197
198 spin_lock_irqsave(&vdev->fh_lock, flags);
199
200 list_for_each_entry(fh, &vdev->fh_list, list)
201 wake_up_all(&fh->wait);
202
203 spin_unlock_irqrestore(&vdev->fh_lock, flags);
204}
205EXPORT_SYMBOL_GPL(v4l2_event_wake_all);
206
207static void __v4l2_event_unsubscribe(struct v4l2_subscribed_event *sev)
208{
209 struct v4l2_fh *fh = sev->fh;
210 unsigned int i;
211
212 lockdep_assert_held(&fh->subscribe_lock);
213 assert_spin_locked(&fh->vdev->fh_lock);
214
215
216 for (i = 0; i < sev->in_use; i++) {
217 list_del(&sev->events[sev_pos(sev, i)].list);
218 fh->navailable--;
219 }
220 list_del(&sev->list);
221}
222
223int v4l2_event_subscribe(struct v4l2_fh *fh,
224 const struct v4l2_event_subscription *sub, unsigned int elems,
225 const struct v4l2_subscribed_event_ops *ops)
226{
227 struct v4l2_subscribed_event *sev, *found_ev;
228 unsigned long flags;
229 unsigned int i;
230 int ret = 0;
231
232 if (sub->type == V4L2_EVENT_ALL)
233 return -EINVAL;
234
235 if (elems < 1)
236 elems = 1;
237
238 sev = kvzalloc(struct_size(sev, events, elems), GFP_KERNEL);
239 if (!sev)
240 return -ENOMEM;
241 for (i = 0; i < elems; i++)
242 sev->events[i].sev = sev;
243 sev->type = sub->type;
244 sev->id = sub->id;
245 sev->flags = sub->flags;
246 sev->fh = fh;
247 sev->ops = ops;
248 sev->elems = elems;
249
250 mutex_lock(&fh->subscribe_lock);
251
252 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
253 found_ev = v4l2_event_subscribed(fh, sub->type, sub->id);
254 if (!found_ev)
255 list_add(&sev->list, &fh->subscribed);
256 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
257
258 if (found_ev) {
259
260 kvfree(sev);
261 } else if (sev->ops && sev->ops->add) {
262 ret = sev->ops->add(sev, elems);
263 if (ret) {
264 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
265 __v4l2_event_unsubscribe(sev);
266 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
267 kvfree(sev);
268 }
269 }
270
271 mutex_unlock(&fh->subscribe_lock);
272
273 return ret;
274}
275EXPORT_SYMBOL_GPL(v4l2_event_subscribe);
276
277void v4l2_event_unsubscribe_all(struct v4l2_fh *fh)
278{
279 struct v4l2_event_subscription sub;
280 struct v4l2_subscribed_event *sev;
281 unsigned long flags;
282
283 do {
284 sev = NULL;
285
286 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
287 if (!list_empty(&fh->subscribed)) {
288 sev = list_first_entry(&fh->subscribed,
289 struct v4l2_subscribed_event, list);
290 sub.type = sev->type;
291 sub.id = sev->id;
292 }
293 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
294 if (sev)
295 v4l2_event_unsubscribe(fh, &sub);
296 } while (sev);
297}
298EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all);
299
300int v4l2_event_unsubscribe(struct v4l2_fh *fh,
301 const struct v4l2_event_subscription *sub)
302{
303 struct v4l2_subscribed_event *sev;
304 unsigned long flags;
305
306 if (sub->type == V4L2_EVENT_ALL) {
307 v4l2_event_unsubscribe_all(fh);
308 return 0;
309 }
310
311 mutex_lock(&fh->subscribe_lock);
312
313 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
314
315 sev = v4l2_event_subscribed(fh, sub->type, sub->id);
316 if (sev != NULL)
317 __v4l2_event_unsubscribe(sev);
318
319 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
320
321 if (sev && sev->ops && sev->ops->del)
322 sev->ops->del(sev);
323
324 mutex_unlock(&fh->subscribe_lock);
325
326 kvfree(sev);
327
328 return 0;
329}
330EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);
331
332int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, struct v4l2_fh *fh,
333 struct v4l2_event_subscription *sub)
334{
335 return v4l2_event_unsubscribe(fh, sub);
336}
337EXPORT_SYMBOL_GPL(v4l2_event_subdev_unsubscribe);
338
339static void v4l2_event_src_replace(struct v4l2_event *old,
340 const struct v4l2_event *new)
341{
342 u32 old_changes = old->u.src_change.changes;
343
344 old->u.src_change = new->u.src_change;
345 old->u.src_change.changes |= old_changes;
346}
347
348static void v4l2_event_src_merge(const struct v4l2_event *old,
349 struct v4l2_event *new)
350{
351 new->u.src_change.changes |= old->u.src_change.changes;
352}
353
354static const struct v4l2_subscribed_event_ops v4l2_event_src_ch_ops = {
355 .replace = v4l2_event_src_replace,
356 .merge = v4l2_event_src_merge,
357};
358
359int v4l2_src_change_event_subscribe(struct v4l2_fh *fh,
360 const struct v4l2_event_subscription *sub)
361{
362 if (sub->type == V4L2_EVENT_SOURCE_CHANGE)
363 return v4l2_event_subscribe(fh, sub, 0, &v4l2_event_src_ch_ops);
364 return -EINVAL;
365}
366EXPORT_SYMBOL_GPL(v4l2_src_change_event_subscribe);
367
368int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd,
369 struct v4l2_fh *fh, struct v4l2_event_subscription *sub)
370{
371 return v4l2_src_change_event_subscribe(fh, sub);
372}
373EXPORT_SYMBOL_GPL(v4l2_src_change_event_subdev_subscribe);
374
