[linux-2.6-block.git] / drivers / media / video / v4l2-event.c

/*
 * v4l2-event.c
 *
 * V4L2 events.
 *
 * Copyright (C) 2009--2010 Nokia Corporation.
 *
 * Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
 *
 * 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 <linux/sched.h>
#include <linux/slab.h>

int v4l2_event_init(struct v4l2_fh *fh)
{
	fh->events = kzalloc(sizeof(*fh->events), GFP_KERNEL);
	if (fh->events == NULL)
		return -ENOMEM;

	init_waitqueue_head(&fh->events->wait);

	INIT_LIST_HEAD(&fh->events->free);
	INIT_LIST_HEAD(&fh->events->available);
	INIT_LIST_HEAD(&fh->events->subscribed);

	fh->events->sequence = -1;

	return 0;
}
EXPORT_SYMBOL_GPL(v4l2_event_init);

int v4l2_event_alloc(struct v4l2_fh *fh, unsigned int n)
{
	struct v4l2_events *events = fh->events;
	unsigned long flags;

	if (!events) {
		WARN_ON(1);
		return -ENOMEM;
	}

	while (events->nallocated < n) {
		struct v4l2_kevent *kev;

		kev = kzalloc(sizeof(*kev), GFP_KERNEL);
		if (kev == NULL)
			return -ENOMEM;

		spin_lock_irqsave(&fh->vdev->fh_lock, flags);
		list_add_tail(&kev->list, &events->free);
		events->nallocated++;
		spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
	}

	return 0;
}
EXPORT_SYMBOL_GPL(v4l2_event_alloc);

#define list_kfree(list, type, member)				\
	while (!list_empty(list)) {				\
		type *hi;					\
		hi = list_first_entry(list, type, member);	\
		list_del(&hi->member);				\
		kfree(hi);					\
	}

void v4l2_event_free(struct v4l2_fh *fh)
{
	struct v4l2_events *events = fh->events;

	if (!events)
		return;

	list_kfree(&events->free, struct v4l2_kevent, list);
	list_kfree(&events->available, struct v4l2_kevent, list);
	list_kfree(&events->subscribed, struct v4l2_subscribed_event, list);

	kfree(events);
	fh->events = NULL;
}
EXPORT_SYMBOL_GPL(v4l2_event_free);

static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)
{
	struct v4l2_events *events = fh->events;
	struct v4l2_kevent *kev;
	unsigned long flags;

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

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

	WARN_ON(events->navailable == 0);

	kev = list_first_entry(&events->available, struct v4l2_kevent, list);
	list_move(&kev->list, &events->free);
	events->navailable--;

	kev->event.pending = events->navailable;
	*event = kev->event;

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

	return 0;
}

int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
		       int nonblocking)
{
	struct v4l2_events *events = fh->events;
	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(events->wait,
					       events->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->event->lock! */
static struct v4l2_subscribed_event *v4l2_event_subscribed(
	struct v4l2_fh *fh, u32 type)
{
	struct v4l2_events *events = fh->events;
	struct v4l2_subscribed_event *sev;

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

	list_for_each_entry(sev, &events->subscribed, list) {
		if (sev->type == type)
			return sev;
	}

	return NULL;
}

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) {
		struct v4l2_events *events = fh->events;
		struct v4l2_kevent *kev;

		/* Are we subscribed? */
		if (!v4l2_event_subscribed(fh, ev->type))
			continue;

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

		/* Do we have any free events? */
		if (list_empty(&events->free))
			continue;

		/* Take one and fill it. */
		kev = list_first_entry(&events->free, struct v4l2_kevent, list);
		kev->event.type = ev->type;
		kev->event.u = ev->u;
		kev->event.timestamp = timestamp;
		kev->event.sequence = events->sequence;
		list_move_tail(&kev->list, &events->available);

		events->navailable++;

		wake_up_all(&events->wait);
	}

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

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

int v4l2_event_subscribe(struct v4l2_fh *fh,
			 struct v4l2_event_subscription *sub)
{
	struct v4l2_events *events = fh->events;
	struct v4l2_subscribed_event *sev;
	unsigned long flags;

	if (fh->events == NULL) {
		WARN_ON(1);
		return -ENOMEM;
	}

	sev = kmalloc(sizeof(*sev), GFP_KERNEL);
	if (!sev)
		return -ENOMEM;

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

	if (v4l2_event_subscribed(fh, sub->type) == NULL) {
		INIT_LIST_HEAD(&sev->list);
		sev->type = sub->type;

		list_add(&sev->list, &events->subscribed);
		sev = NULL;
	}

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

	kfree(sev);

	return 0;
}
EXPORT_SYMBOL_GPL(v4l2_event_subscribe);

static void v4l2_event_unsubscribe_all(struct v4l2_fh *fh)
{
	struct v4l2_events *events = fh->events;
	struct v4l2_subscribed_event *sev;
	unsigned long flags;

	do {
		sev = NULL;

		spin_lock_irqsave(&fh->vdev->fh_lock, flags);
		if (!list_empty(&events->subscribed)) {
			sev = list_first_entry(&events->subscribed,
				       struct v4l2_subscribed_event, list);
			list_del(&sev->list);
		}
		spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
		kfree(sev);
	} while (sev);
}

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);
	if (sev != NULL)
		list_del(&sev->list);

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

	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 <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
	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	}
0a4f8d07	48	EXPORT_SYMBOL_GPL(v4l2_event_init);
c3b5b024 SA	49
	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
	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
	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
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
ee6869af HV	137	/* Release the vdev lock while waiting */
	138	if (fh->vdev->lock)
	139	mutex_unlock(fh->vdev->lock);
	140
c3b5b024 SA	141	do {
	142	ret = wait_event_interruptible(events->wait,
	143	events->navailable != 0);
	144	if (ret < 0)
ee6869af	145	break;
c3b5b024 SA	146
	147	ret = __v4l2_event_dequeue(fh, event);
	148	} while (ret == -ENOENT);
	149
ee6869af HV	150	if (fh->vdev->lock)
	151	mutex_lock(fh->vdev->lock);
	152
c3b5b024 SA	153	return ret;
c3b5b024 SA	154	}
0a4f8d07	155	EXPORT_SYMBOL_GPL(v4l2_event_dequeue);
c3b5b024 SA	156
	157	/* Caller must hold fh->event->lock! */
	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
f3cd385a	164	assert_spin_locked(&fh->vdev->fh_lock);
c3b5b024 SA	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
	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(&timestamp);
	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
	216	int v4l2_event_pending(struct v4l2_fh *fh)
	217	{
	218	return fh->events->navailable;
	219	}
	220	EXPORT_SYMBOL_GPL(v4l2_event_pending);
	221
	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
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
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);