[linux.git] / drivers / media / video / v4l2-event.c

/*
 * v4l2-event.c
 *
 * V4L2 events.
 *
 * Copyright (C) 2009--2010 Nokia Corporation.
 *
 * Contact: Sakari Ailus <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <media/v4l2-dev.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>
#include <media/v4l2-ctrls.h>

#include <linux/sched.h>
#include <linux/slab.h>

static unsigned sev_pos(const struct v4l2_subscribed_event *sev, unsigned idx)
{
	idx += sev->first;
	return idx >= sev->elems ? idx - sev->elems : idx;
}

static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)
{
	struct v4l2_kevent *kev;
	unsigned long flags;

	spin_lock_irqsave(&fh->vdev->fh_lock, flags);

	if (list_empty(&fh->available)) {
		spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
		return -ENOENT;
	}

	WARN_ON(fh->navailable == 0);

	kev = list_first_entry(&fh->available, struct v4l2_kevent, list);
	list_del(&kev->list);
	fh->navailable--;

	kev->event.pending = fh->navailable;
	*event = kev->event;
	kev->sev->first = sev_pos(kev->sev, 1);
	kev->sev->in_use--;

	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);

	return 0;
}

int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
		       int nonblocking)
{
	int ret;

	if (nonblocking)
		return __v4l2_event_dequeue(fh, event);

	/* Release the vdev lock while waiting */
	if (fh->vdev->lock)
		mutex_unlock(fh->vdev->lock);

	do {
		ret = wait_event_interruptible(fh->wait,
					       fh->navailable != 0);
		if (ret < 0)
			break;

		ret = __v4l2_event_dequeue(fh, event);
	} while (ret == -ENOENT);

	if (fh->vdev->lock)
		mutex_lock(fh->vdev->lock);

	return ret;
}
EXPORT_SYMBOL_GPL(v4l2_event_dequeue);

/* Caller must hold fh->vdev->fh_lock! */
static struct v4l2_subscribed_event *v4l2_event_subscribed(
		struct v4l2_fh *fh, u32 type, u32 id)
{
	struct v4l2_subscribed_event *sev;

	assert_spin_locked(&fh->vdev->fh_lock);

	list_for_each_entry(sev, &fh->subscribed, list)
		if (sev->type == type && sev->id == id)
			return sev;

	return NULL;
}

static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev,
		const struct timespec *ts)
{
	struct v4l2_subscribed_event *sev;
	struct v4l2_kevent *kev;
	bool copy_payload = true;

	/* Are we subscribed? */
	sev = v4l2_event_subscribed(fh, ev->type, ev->id);
	if (sev == NULL)
		return;

	/* Increase event sequence number on fh. */
	fh->sequence++;

	/* Do we have any free events? */
	if (sev->in_use == sev->elems) {
		/* no, remove the oldest one */
		kev = sev->events + sev_pos(sev, 0);
		list_del(&kev->list);
		sev->in_use--;
		sev->first = sev_pos(sev, 1);
		fh->navailable--;
		if (sev->elems == 1) {
			if (sev->replace) {
				sev->replace(&kev->event, ev);
				copy_payload = false;
			}
		} else if (sev->merge) {
			struct v4l2_kevent *second_oldest =
				sev->events + sev_pos(sev, 0);
			sev->merge(&kev->event, &second_oldest->event);
		}
	}

	/* Take one and fill it. */
	kev = sev->events + sev_pos(sev, sev->in_use);
	kev->event.type = ev->type;
	if (copy_payload)
		kev->event.u = ev->u;
	kev->event.id = ev->id;
	kev->event.timestamp = *ts;
	kev->event.sequence = fh->sequence;
	sev->in_use++;
	list_add_tail(&kev->list, &fh->available);

	fh->navailable++;

	wake_up_all(&fh->wait);
}

void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev)
{
	struct v4l2_fh *fh;
	unsigned long flags;
	struct timespec timestamp;

	ktime_get_ts(&timestamp);

	spin_lock_irqsave(&vdev->fh_lock, flags);

	list_for_each_entry(fh, &vdev->fh_list, list)
		__v4l2_event_queue_fh(fh, ev, &timestamp);

	spin_unlock_irqrestore(&vdev->fh_lock, flags);
}
EXPORT_SYMBOL_GPL(v4l2_event_queue);

void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev)
{
	unsigned long flags;
	struct timespec timestamp;

	ktime_get_ts(&timestamp);

	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
	__v4l2_event_queue_fh(fh, ev, &timestamp);
	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
}
EXPORT_SYMBOL_GPL(v4l2_event_queue_fh);

int v4l2_event_pending(struct v4l2_fh *fh)
{
	return fh->navailable;
}
EXPORT_SYMBOL_GPL(v4l2_event_pending);

static void ctrls_replace(struct v4l2_event *old, const struct v4l2_event *new)
{
	u32 old_changes = old->u.ctrl.changes;

	old->u.ctrl = new->u.ctrl;
	old->u.ctrl.changes |= old_changes;
}

static void ctrls_merge(const struct v4l2_event *old, struct v4l2_event *new)
{
	new->u.ctrl.changes |= old->u.ctrl.changes;
}

int v4l2_event_subscribe(struct v4l2_fh *fh,
			 struct v4l2_event_subscription *sub, unsigned elems)
{
	struct v4l2_subscribed_event *sev, *found_ev;
	struct v4l2_ctrl *ctrl = NULL;
	unsigned long flags;
	unsigned i;

	if (elems < 1)
		elems = 1;
	if (sub->type == V4L2_EVENT_CTRL) {
		ctrl = v4l2_ctrl_find(fh->ctrl_handler, sub->id);
		if (ctrl == NULL)
			return -EINVAL;
	}

	sev = kzalloc(sizeof(*sev) + sizeof(struct v4l2_kevent) * elems, GFP_KERNEL);
	if (!sev)
		return -ENOMEM;
	for (i = 0; i < elems; i++)
		sev->events[i].sev = sev;
	sev->type = sub->type;
	sev->id = sub->id;
	sev->flags = sub->flags;
	sev->fh = fh;
	sev->elems = elems;
	if (ctrl) {
		sev->replace = ctrls_replace;
		sev->merge = ctrls_merge;
	}

	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
	found_ev = v4l2_event_subscribed(fh, sub->type, sub->id);
	if (!found_ev)
		list_add(&sev->list, &fh->subscribed);
	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);

	/* v4l2_ctrl_add_event uses a mutex, so do this outside the spin lock */
	if (found_ev)
		kfree(sev);
	else if (ctrl)
		v4l2_ctrl_add_event(ctrl, sev);

	return 0;
}
EXPORT_SYMBOL_GPL(v4l2_event_subscribe);

void v4l2_event_unsubscribe_all(struct v4l2_fh *fh)
{
	struct v4l2_event_subscription sub;
	struct v4l2_subscribed_event *sev;
	unsigned long flags;

	do {
		sev = NULL;

		spin_lock_irqsave(&fh->vdev->fh_lock, flags);
		if (!list_empty(&fh->subscribed)) {
			sev = list_first_entry(&fh->subscribed,
					struct v4l2_subscribed_event, list);
			sub.type = sev->type;
			sub.id = sev->id;
		}
		spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
		if (sev)
			v4l2_event_unsubscribe(fh, &sub);
	} while (sev);
}
EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all);

int v4l2_event_unsubscribe(struct v4l2_fh *fh,
			   struct v4l2_event_subscription *sub)
{
	struct v4l2_subscribed_event *sev;
	unsigned long flags;

	if (sub->type == V4L2_EVENT_ALL) {
		v4l2_event_unsubscribe_all(fh);
		return 0;
	}

	spin_lock_irqsave(&fh->vdev->fh_lock, flags);

	sev = v4l2_event_subscribed(fh, sub->type, sub->id);
	if (sev != NULL) {
		list_del(&sev->list);
		sev->fh = NULL;
	}

	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
	if (sev && sev->type == V4L2_EVENT_CTRL) {
		struct v4l2_ctrl *ctrl = v4l2_ctrl_find(fh->ctrl_handler, sev->id);

		if (ctrl)
			v4l2_ctrl_del_event(ctrl, sev);
	}

	kfree(sev);

	return 0;
}
EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);
Commit	Line	Data
c3b5b024 SA	1	/*
	2	* v4l2-event.c
	3	*
	4	* V4L2 events.
	5	*
	6	* Copyright (C) 2009--2010 Nokia Corporation.
	7	*
	8	* Contact: Sakari Ailus <[email protected]>
	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>
6e239399	28	#include <media/v4l2-ctrls.h>
c3b5b024 SA	29
	30	#include <linux/sched.h>
	31	#include <linux/slab.h>
	32
f1e393de	33	static unsigned sev_pos(const struct v4l2_subscribed_event *sev, unsigned idx)
c3b5b024	34	{
f1e393de HV	35	idx += sev->first;
f1e393de HV	36	return idx >= sev->elems ? idx - sev->elems : idx;
c3b5b024	37	}
c3b5b024 SA	38
	39	static int __v4l2_event_dequeue(struct v4l2_fh fh, struct v4l2_event event)
	40	{
c3b5b024 SA	41	struct v4l2_kevent *kev;
	42	unsigned long flags;
	43
	44	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
	45
523f46d6	46	if (list_empty(&fh->available)) {
c3b5b024 SA	47	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
	48	return -ENOENT;
	49	}
	50
523f46d6	51	WARN_ON(fh->navailable == 0);
c3b5b024	52
523f46d6	53	kev = list_first_entry(&fh->available, struct v4l2_kevent, list);
f1e393de	54	list_del(&kev->list);
523f46d6	55	fh->navailable--;
c3b5b024	56
523f46d6	57	kev->event.pending = fh->navailable;
c3b5b024	58	*event = kev->event;
f1e393de HV	59	kev->sev->first = sev_pos(kev->sev, 1);
f1e393de HV	60	kev->sev->in_use--;
c3b5b024 SA	61
	62	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
	63
	64	return 0;
	65	}
	66
	67	int v4l2_event_dequeue(struct v4l2_fh fh, struct v4l2_event event,
	68	int nonblocking)
	69	{
c3b5b024 SA	70	int ret;
	71
	72	if (nonblocking)
	73	return __v4l2_event_dequeue(fh, event);
	74
ee6869af HV	75	/* Release the vdev lock while waiting */
	76	if (fh->vdev->lock)
	77	mutex_unlock(fh->vdev->lock);
	78
c3b5b024	79	do {
523f46d6 HV	80	ret = wait_event_interruptible(fh->wait,
523f46d6 HV	81	fh->navailable != 0);
c3b5b024	82	if (ret < 0)
ee6869af	83	break;
c3b5b024 SA	84
	85	ret = __v4l2_event_dequeue(fh, event);
	86	} while (ret == -ENOENT);
	87
ee6869af HV	88	if (fh->vdev->lock)
	89	mutex_lock(fh->vdev->lock);
	90
c3b5b024 SA	91	return ret;
c3b5b024 SA	92	}
0a4f8d07	93	EXPORT_SYMBOL_GPL(v4l2_event_dequeue);
c3b5b024	94
6e239399	95	/* Caller must hold fh->vdev->fh_lock! */
c3b5b024	96	static struct v4l2_subscribed_event *v4l2_event_subscribed(
6e239399	97	struct v4l2_fh *fh, u32 type, u32 id)
c3b5b024	98	{
c3b5b024 SA	99	struct v4l2_subscribed_event *sev;
c3b5b024 SA	100
f3cd385a	101	assert_spin_locked(&fh->vdev->fh_lock);
c3b5b024	102
3f66f0ed	103	list_for_each_entry(sev, &fh->subscribed, list)
6e239399	104	if (sev->type == type && sev->id == id)
c3b5b024	105	return sev;
c3b5b024 SA	106
	107	return NULL;
	108	}
	109
6e239399 HV	110	static void __v4l2_event_queue_fh(struct v4l2_fh fh, const struct v4l2_event ev,
	111	const struct timespec *ts)
	112	{
6e239399 HV	113	struct v4l2_subscribed_event *sev;
6e239399 HV	114	struct v4l2_kevent *kev;
2151bdc8	115	bool copy_payload = true;
6e239399 HV	116
	117	/* Are we subscribed? */
	118	sev = v4l2_event_subscribed(fh, ev->type, ev->id);
	119	if (sev == NULL)
	120	return;
	121
	122	/* Increase event sequence number on fh. */
523f46d6	123	fh->sequence++;
6e239399 HV	124
6e239399 HV	125	/* Do we have any free events? */
f1e393de HV	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);
	130	sev->in_use--;
	131	sev->first = sev_pos(sev, 1);
	132	fh->navailable--;
2151bdc8 HV	133	if (sev->elems == 1) {
	134	if (sev->replace) {
	135	sev->replace(&kev->event, ev);
	136	copy_payload = false;
	137	}
	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);
	142	}
f1e393de	143	}
6e239399 HV	144
6e239399 HV	145	/* Take one and fill it. */
f1e393de	146	kev = sev->events + sev_pos(sev, sev->in_use);
6e239399	147	kev->event.type = ev->type;
2151bdc8 HV	148	if (copy_payload)
2151bdc8 HV	149	kev->event.u = ev->u;
6e239399 HV	150	kev->event.id = ev->id;
6e239399 HV	151	kev->event.timestamp = *ts;
523f46d6	152	kev->event.sequence = fh->sequence;
f1e393de HV	153	sev->in_use++;
f1e393de HV	154	list_add_tail(&kev->list, &fh->available);
6e239399	155
523f46d6	156	fh->navailable++;
6e239399	157
523f46d6	158	wake_up_all(&fh->wait);
6e239399 HV	159	}
6e239399 HV	160
c3b5b024 SA	161	void v4l2_event_queue(struct video_device vdev, const struct v4l2_event ev)
	162	{
	163	struct v4l2_fh *fh;
	164	unsigned long flags;
	165	struct timespec timestamp;
	166
	167	ktime_get_ts(&timestamp);
	168
	169	spin_lock_irqsave(&vdev->fh_lock, flags);
	170
3f66f0ed	171	list_for_each_entry(fh, &vdev->fh_list, list)
6e239399	172	__v4l2_event_queue_fh(fh, ev, &timestamp);
c3b5b024 SA	173
	174	spin_unlock_irqrestore(&vdev->fh_lock, flags);
	175	}
	176	EXPORT_SYMBOL_GPL(v4l2_event_queue);
	177
6e239399 HV	178	void v4l2_event_queue_fh(struct v4l2_fh fh, const struct v4l2_event ev)
	179	{
	180	unsigned long flags;
	181	struct timespec timestamp;
	182
	183	ktime_get_ts(&timestamp);
	184
	185	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
	186	__v4l2_event_queue_fh(fh, ev, &timestamp);
	187	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
	188	}
	189	EXPORT_SYMBOL_GPL(v4l2_event_queue_fh);
	190
c3b5b024 SA	191	int v4l2_event_pending(struct v4l2_fh *fh)
c3b5b024 SA	192	{
523f46d6	193	return fh->navailable;
c3b5b024 SA	194	}
	195	EXPORT_SYMBOL_GPL(v4l2_event_pending);
	196
2151bdc8 HV	197	static void ctrls_replace(struct v4l2_event old, const struct v4l2_event new)
	198	{
	199	u32 old_changes = old->u.ctrl.changes;
	200
	201	old->u.ctrl = new->u.ctrl;
	202	old->u.ctrl.changes \|= old_changes;
	203	}
	204
	205	static void ctrls_merge(const struct v4l2_event old, struct v4l2_event new)
	206	{
	207	new->u.ctrl.changes \|= old->u.ctrl.changes;
	208	}
	209
c3b5b024	210	int v4l2_event_subscribe(struct v4l2_fh *fh,
f1e393de	211	struct v4l2_event_subscription *sub, unsigned elems)
c3b5b024	212	{
6e239399 HV	213	struct v4l2_subscribed_event sev, found_ev;
6e239399 HV	214	struct v4l2_ctrl *ctrl = NULL;
c3b5b024	215	unsigned long flags;
f1e393de	216	unsigned i;
c3b5b024	217
f1e393de HV	218	if (elems < 1)
f1e393de HV	219	elems = 1;
6e239399 HV	220	if (sub->type == V4L2_EVENT_CTRL) {
	221	ctrl = v4l2_ctrl_find(fh->ctrl_handler, sub->id);
	222	if (ctrl == NULL)
	223	return -EINVAL;
	224	}
	225
f1e393de	226	sev = kzalloc(sizeof(sev) + sizeof(struct v4l2_kevent) elems, GFP_KERNEL);
c3b5b024 SA	227	if (!sev)
c3b5b024 SA	228	return -ENOMEM;
f1e393de HV	229	for (i = 0; i < elems; i++)
	230	sev->events[i].sev = sev;
	231	sev->type = sub->type;
	232	sev->id = sub->id;
	233	sev->flags = sub->flags;
	234	sev->fh = fh;
	235	sev->elems = elems;
2151bdc8 HV	236	if (ctrl) {
	237	sev->replace = ctrls_replace;
	238	sev->merge = ctrls_merge;
	239	}
c3b5b024 SA	240
c3b5b024 SA	241	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
6e239399	242	found_ev = v4l2_event_subscribed(fh, sub->type, sub->id);
f1e393de	243	if (!found_ev)
523f46d6	244	list_add(&sev->list, &fh->subscribed);
c3b5b024 SA	245	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
c3b5b024 SA	246
f1e393de	247	/* v4l2_ctrl_add_event uses a mutex, so do this outside the spin lock */
77068d36 HV	248	if (found_ev)
	249	kfree(sev);
	250	else if (ctrl)
	251	v4l2_ctrl_add_event(ctrl, sev);
c3b5b024 SA	252
	253	return 0;
	254	}
	255	EXPORT_SYMBOL_GPL(v4l2_event_subscribe);
	256
f1e393de	257	void v4l2_event_unsubscribe_all(struct v4l2_fh *fh)
c3b5b024	258	{
6e239399	259	struct v4l2_event_subscription sub;
c3b5b024 SA	260	struct v4l2_subscribed_event *sev;
	261	unsigned long flags;
	262
	263	do {
	264	sev = NULL;
	265
	266	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
523f46d6 HV	267	if (!list_empty(&fh->subscribed)) {
523f46d6 HV	268	sev = list_first_entry(&fh->subscribed,
6e239399 HV	269	struct v4l2_subscribed_event, list);
	270	sub.type = sev->type;
	271	sub.id = sev->id;
c3b5b024 SA	272	}
c3b5b024 SA	273	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
6e239399 HV	274	if (sev)
6e239399 HV	275	v4l2_event_unsubscribe(fh, &sub);
c3b5b024 SA	276	} while (sev);
c3b5b024 SA	277	}
f1e393de	278	EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all);
c3b5b024 SA	279
	280	int v4l2_event_unsubscribe(struct v4l2_fh *fh,
	281	struct v4l2_event_subscription *sub)
	282	{
	283	struct v4l2_subscribed_event *sev;
	284	unsigned long flags;
	285
	286	if (sub->type == V4L2_EVENT_ALL) {
	287	v4l2_event_unsubscribe_all(fh);
	288	return 0;
	289	}
	290
	291	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
	292
6e239399	293	sev = v4l2_event_subscribed(fh, sub->type, sub->id);
77068d36	294	if (sev != NULL) {
c3b5b024	295	list_del(&sev->list);
77068d36 HV	296	sev->fh = NULL;
77068d36 HV	297	}
c3b5b024 SA	298
c3b5b024 SA	299	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
77068d36	300	if (sev && sev->type == V4L2_EVENT_CTRL) {
6e239399 HV	301	struct v4l2_ctrl *ctrl = v4l2_ctrl_find(fh->ctrl_handler, sev->id);
	302
	303	if (ctrl)
77068d36	304	v4l2_ctrl_del_event(ctrl, sev);
6e239399	305	}
c3b5b024 SA	306
	307	kfree(sev);
	308
	309	return 0;
	310	}
	311	EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);