drivers/media/video/v4l2-event.c - kernel/skids - Git at Google

 /*
  * 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);

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

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

 	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);
	/*
	* 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);

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

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

	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);