1 // SPDX-License-Identifier: GPL-2.0-only
7 * Copyright (C) 2009--2010 Nokia Corporation.
9 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
12 #include <media/v4l2-dev.h>
13 #include <media/v4l2-fh.h>
14 #include <media/v4l2-event.h>
17 #include <linux/sched.h>
18 #include <linux/slab.h>
19 #include <linux/export.h>
21 static unsigned sev_pos(const struct v4l2_subscribed_event *sev, unsigned idx)
24 return idx >= sev->elems ? idx - sev->elems : idx;
27 static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)
29 struct v4l2_kevent *kev;
33 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
35 if (list_empty(&fh->available)) {
36 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
40 WARN_ON(fh->navailable == 0);
42 kev = list_first_entry(&fh->available, struct v4l2_kevent, list);
46 kev->event.pending = fh->navailable;
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);
54 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
59 int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
65 return __v4l2_event_dequeue(fh, event);
67 /* Release the vdev lock while waiting */
69 mutex_unlock(fh->vdev->lock);
72 ret = wait_event_interruptible(fh->wait,
77 ret = __v4l2_event_dequeue(fh, event);
78 } while (ret == -ENOENT);
81 mutex_lock(fh->vdev->lock);
85 EXPORT_SYMBOL_GPL(v4l2_event_dequeue);
87 /* Caller must hold fh->vdev->fh_lock! */
88 static struct v4l2_subscribed_event *v4l2_event_subscribed(
89 struct v4l2_fh *fh, u32 type, u32 id)
91 struct v4l2_subscribed_event *sev;
93 assert_spin_locked(&fh->vdev->fh_lock);
95 list_for_each_entry(sev, &fh->subscribed, list)
96 if (sev->type == type && sev->id == id)
102 static void __v4l2_event_queue_fh(struct v4l2_fh *fh,
103 const struct v4l2_event *ev, u64 ts)
105 struct v4l2_subscribed_event *sev;
106 struct v4l2_kevent *kev;
107 bool copy_payload = true;
109 /* Are we subscribed? */
110 sev = v4l2_event_subscribed(fh, ev->type, ev->id);
114 /* Increase event sequence number on fh. */
117 /* Do we have any free events? */
118 if (sev->in_use == sev->elems) {
119 /* no, remove the oldest one */
120 kev = sev->events + sev_pos(sev, 0);
121 list_del(&kev->list);
123 sev->first = sev_pos(sev, 1);
125 if (sev->elems == 1) {
126 if (sev->ops && sev->ops->replace) {
127 sev->ops->replace(&kev->event, ev);
128 copy_payload = false;
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);
137 /* Take one and fill it. */
138 kev = sev->events + sev_pos(sev, sev->in_use);
139 kev->event.type = ev->type;
141 kev->event.u = ev->u;
142 kev->event.id = ev->id;
144 kev->event.sequence = fh->sequence;
146 list_add_tail(&kev->list, &fh->available);
150 wake_up_all(&fh->wait);
153 void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev)
164 spin_lock_irqsave(&vdev->fh_lock, flags);
166 list_for_each_entry(fh, &vdev->fh_list, list)
167 __v4l2_event_queue_fh(fh, ev, ts);
169 spin_unlock_irqrestore(&vdev->fh_lock, flags);
171 EXPORT_SYMBOL_GPL(v4l2_event_queue);
173 void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev)
176 u64 ts = ktime_get_ns();
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);
182 EXPORT_SYMBOL_GPL(v4l2_event_queue_fh);
184 int v4l2_event_pending(struct v4l2_fh *fh)
186 return fh->navailable;
188 EXPORT_SYMBOL_GPL(v4l2_event_pending);
190 static void __v4l2_event_unsubscribe(struct v4l2_subscribed_event *sev)
192 struct v4l2_fh *fh = sev->fh;
195 lockdep_assert_held(&fh->subscribe_lock);
196 assert_spin_locked(&fh->vdev->fh_lock);
198 /* Remove any pending events for this subscription */
199 for (i = 0; i < sev->in_use; i++) {
200 list_del(&sev->events[sev_pos(sev, i)].list);
203 list_del(&sev->list);
206 int v4l2_event_subscribe(struct v4l2_fh *fh,
207 const struct v4l2_event_subscription *sub, unsigned elems,
208 const struct v4l2_subscribed_event_ops *ops)
210 struct v4l2_subscribed_event *sev, *found_ev;
215 if (sub->type == V4L2_EVENT_ALL)
221 sev = kvzalloc(struct_size(sev, events, elems), GFP_KERNEL);
224 for (i = 0; i < elems; i++)
225 sev->events[i].sev = sev;
226 sev->type = sub->type;
228 sev->flags = sub->flags;
233 mutex_lock(&fh->subscribe_lock);
235 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
236 found_ev = v4l2_event_subscribed(fh, sub->type, sub->id);
238 list_add(&sev->list, &fh->subscribed);
239 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
242 /* Already listening */
244 } else if (sev->ops && sev->ops->add) {
245 ret = sev->ops->add(sev, elems);
247 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
248 __v4l2_event_unsubscribe(sev);
249 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
254 mutex_unlock(&fh->subscribe_lock);
258 EXPORT_SYMBOL_GPL(v4l2_event_subscribe);
260 void v4l2_event_unsubscribe_all(struct v4l2_fh *fh)
262 struct v4l2_event_subscription sub;
263 struct v4l2_subscribed_event *sev;
269 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
270 if (!list_empty(&fh->subscribed)) {
271 sev = list_first_entry(&fh->subscribed,
272 struct v4l2_subscribed_event, list);
273 sub.type = sev->type;
276 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
278 v4l2_event_unsubscribe(fh, &sub);
281 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all);
283 int v4l2_event_unsubscribe(struct v4l2_fh *fh,
284 const struct v4l2_event_subscription *sub)
286 struct v4l2_subscribed_event *sev;
289 if (sub->type == V4L2_EVENT_ALL) {
290 v4l2_event_unsubscribe_all(fh);
294 mutex_lock(&fh->subscribe_lock);
296 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
298 sev = v4l2_event_subscribed(fh, sub->type, sub->id);
300 __v4l2_event_unsubscribe(sev);
302 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
304 if (sev && sev->ops && sev->ops->del)
307 mutex_unlock(&fh->subscribe_lock);
313 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);
315 int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, struct v4l2_fh *fh,
316 struct v4l2_event_subscription *sub)
318 return v4l2_event_unsubscribe(fh, sub);
320 EXPORT_SYMBOL_GPL(v4l2_event_subdev_unsubscribe);
322 static void v4l2_event_src_replace(struct v4l2_event *old,
323 const struct v4l2_event *new)
325 u32 old_changes = old->u.src_change.changes;
327 old->u.src_change = new->u.src_change;
328 old->u.src_change.changes |= old_changes;
331 static void v4l2_event_src_merge(const struct v4l2_event *old,
332 struct v4l2_event *new)
334 new->u.src_change.changes |= old->u.src_change.changes;
337 static const struct v4l2_subscribed_event_ops v4l2_event_src_ch_ops = {
338 .replace = v4l2_event_src_replace,
339 .merge = v4l2_event_src_merge,
342 int v4l2_src_change_event_subscribe(struct v4l2_fh *fh,
343 const struct v4l2_event_subscription *sub)
345 if (sub->type == V4L2_EVENT_SOURCE_CHANGE)
346 return v4l2_event_subscribe(fh, sub, 0, &v4l2_event_src_ch_ops);
349 EXPORT_SYMBOL_GPL(v4l2_src_change_event_subscribe);
351 int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd,
352 struct v4l2_fh *fh, struct v4l2_event_subscription *sub)
354 return v4l2_src_change_event_subscribe(fh, sub);
356 EXPORT_SYMBOL_GPL(v4l2_src_change_event_subdev_subscribe);