6 * Copyright (C) 2009--2010 Nokia Corporation.
8 * Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
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.
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.
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
25 #include <media/v4l2-dev.h>
26 #include <media/v4l2-fh.h>
27 #include <media/v4l2-event.h>
28 #include <media/v4l2-ctrls.h>
30 #include <linux/sched.h>
31 #include <linux/slab.h>
33 static unsigned sev_pos(const struct v4l2_subscribed_event *sev, unsigned idx)
36 return idx >= sev->elems ? idx - sev->elems : idx;
39 static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)
41 struct v4l2_kevent *kev;
44 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
46 if (list_empty(&fh->available)) {
47 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
51 WARN_ON(fh->navailable == 0);
53 kev = list_first_entry(&fh->available, struct v4l2_kevent, list);
57 kev->event.pending = fh->navailable;
59 kev->sev->first = sev_pos(kev->sev, 1);
62 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
67 int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
73 return __v4l2_event_dequeue(fh, event);
75 /* Release the vdev lock while waiting */
77 mutex_unlock(fh->vdev->lock);
80 ret = wait_event_interruptible(fh->wait,
85 ret = __v4l2_event_dequeue(fh, event);
86 } while (ret == -ENOENT);
89 mutex_lock(fh->vdev->lock);
93 EXPORT_SYMBOL_GPL(v4l2_event_dequeue);
95 /* Caller must hold fh->vdev->fh_lock! */
96 static struct v4l2_subscribed_event *v4l2_event_subscribed(
97 struct v4l2_fh *fh, u32 type, u32 id)
99 struct v4l2_subscribed_event *sev;
101 assert_spin_locked(&fh->vdev->fh_lock);
103 list_for_each_entry(sev, &fh->subscribed, list)
104 if (sev->type == type && sev->id == id)
110 static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev,
111 const struct timespec *ts)
113 struct v4l2_subscribed_event *sev;
114 struct v4l2_kevent *kev;
115 bool copy_payload = true;
117 /* Are we subscribed? */
118 sev = v4l2_event_subscribed(fh, ev->type, ev->id);
122 /* Increase event sequence number on fh. */
125 /* Do we have any free events? */
126 if (sev->in_use == sev->elems) {
127 /* no, remove the oldest one */
128 kev = sev->events + sev_pos(sev, 0);
129 list_del(&kev->list);
131 sev->first = sev_pos(sev, 1);
133 if (sev->elems == 1) {
135 sev->replace(&kev->event, ev);
136 copy_payload = false;
138 } else if (sev->merge) {
139 struct v4l2_kevent *second_oldest =
140 sev->events + sev_pos(sev, 0);
141 sev->merge(&kev->event, &second_oldest->event);
145 /* Take one and fill it. */
146 kev = sev->events + sev_pos(sev, sev->in_use);
147 kev->event.type = ev->type;
149 kev->event.u = ev->u;
150 kev->event.id = ev->id;
151 kev->event.timestamp = *ts;
152 kev->event.sequence = fh->sequence;
154 list_add_tail(&kev->list, &fh->available);
158 wake_up_all(&fh->wait);
161 void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev)
165 struct timespec timestamp;
167 ktime_get_ts(×tamp);
169 spin_lock_irqsave(&vdev->fh_lock, flags);
171 list_for_each_entry(fh, &vdev->fh_list, list)
172 __v4l2_event_queue_fh(fh, ev, ×tamp);
174 spin_unlock_irqrestore(&vdev->fh_lock, flags);
176 EXPORT_SYMBOL_GPL(v4l2_event_queue);
178 void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev)
181 struct timespec timestamp;
183 ktime_get_ts(×tamp);
185 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
186 __v4l2_event_queue_fh(fh, ev, ×tamp);
187 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
189 EXPORT_SYMBOL_GPL(v4l2_event_queue_fh);
191 int v4l2_event_pending(struct v4l2_fh *fh)
193 return fh->navailable;
195 EXPORT_SYMBOL_GPL(v4l2_event_pending);
197 static void ctrls_replace(struct v4l2_event *old, const struct v4l2_event *new)
199 u32 old_changes = old->u.ctrl.changes;
201 old->u.ctrl = new->u.ctrl;
202 old->u.ctrl.changes |= old_changes;
205 static void ctrls_merge(const struct v4l2_event *old, struct v4l2_event *new)
207 new->u.ctrl.changes |= old->u.ctrl.changes;
210 int v4l2_event_subscribe(struct v4l2_fh *fh,
211 struct v4l2_event_subscription *sub, unsigned elems)
213 struct v4l2_subscribed_event *sev, *found_ev;
214 struct v4l2_ctrl *ctrl = NULL;
220 if (sub->type == V4L2_EVENT_CTRL) {
221 ctrl = v4l2_ctrl_find(fh->ctrl_handler, sub->id);
226 sev = kzalloc(sizeof(*sev) + sizeof(struct v4l2_kevent) * elems, GFP_KERNEL);
229 for (i = 0; i < elems; i++)
230 sev->events[i].sev = sev;
231 sev->type = sub->type;
233 sev->flags = sub->flags;
237 sev->replace = ctrls_replace;
238 sev->merge = ctrls_merge;
241 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
242 found_ev = v4l2_event_subscribed(fh, sub->type, sub->id);
244 list_add(&sev->list, &fh->subscribed);
245 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
247 /* v4l2_ctrl_add_event uses a mutex, so do this outside the spin lock */
251 v4l2_ctrl_add_event(ctrl, sev);
255 EXPORT_SYMBOL_GPL(v4l2_event_subscribe);
257 void v4l2_event_unsubscribe_all(struct v4l2_fh *fh)
259 struct v4l2_event_subscription sub;
260 struct v4l2_subscribed_event *sev;
266 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
267 if (!list_empty(&fh->subscribed)) {
268 sev = list_first_entry(&fh->subscribed,
269 struct v4l2_subscribed_event, list);
270 sub.type = sev->type;
273 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
275 v4l2_event_unsubscribe(fh, &sub);
278 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all);
280 int v4l2_event_unsubscribe(struct v4l2_fh *fh,
281 struct v4l2_event_subscription *sub)
283 struct v4l2_subscribed_event *sev;
286 if (sub->type == V4L2_EVENT_ALL) {
287 v4l2_event_unsubscribe_all(fh);
291 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
293 sev = v4l2_event_subscribed(fh, sub->type, sub->id);
295 list_del(&sev->list);
299 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
300 if (sev && sev->type == V4L2_EVENT_CTRL) {
301 struct v4l2_ctrl *ctrl = v4l2_ctrl_find(fh->ctrl_handler, sev->id);
304 v4l2_ctrl_del_event(ctrl, sev);
311 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);