drivers/media/v4l2-core/v4l2-event.c - linux - Git at Google

 /*
  * v4l2-event.c
  *
  * V4L2 events.
  *
  * Copyright (C) 2009--2010 Nokia Corporation.
  *
  * Contact: Sakari Ailus <sakari.ailus@iki.fi>
  *
  * 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.
  */

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

 #include <linux/mm.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/export.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->ops && sev->ops->replace) {
 				sev->ops->replace(&kev->event, ev);
 				copy_payload = false;
 			}
 		} else if (sev->ops && sev->ops->merge) {
 			struct v4l2_kevent *second_oldest =
 				sev->events + sev_pos(sev, 0);
 			sev->ops->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;

 	if (vdev == NULL)
 		return;

 	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);

 int v4l2_event_subscribe(struct v4l2_fh *fh,
 			 const struct v4l2_event_subscription *sub, unsigned elems,
 			 const struct v4l2_subscribed_event_ops *ops)
 {
 	struct v4l2_subscribed_event *sev, *found_ev;
 	unsigned long flags;
 	unsigned i;
 	int ret = 0;

 	if (sub->type == V4L2_EVENT_ALL)
 		return -EINVAL;

 	if (elems < 1)
 		elems = 1;

 	sev = kvzalloc(struct_size(sev, events, 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->ops = ops;
 	sev->elems = elems;

 	mutex_lock(&fh->subscribe_lock);

 	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
 	found_ev = v4l2_event_subscribed(fh, sub->type, sub->id);
 	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);

 	if (found_ev) {
 		/* Already listening */
 		kvfree(sev);
 		goto out_unlock;
 	}

 	if (sev->ops && sev->ops->add) {
 		ret = sev->ops->add(sev, elems);
 		if (ret) {
 			kvfree(sev);
 			goto out_unlock;
 		}
 	}

 	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
 	list_add(&sev->list, &fh->subscribed);
 	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);

 out_unlock:
 	mutex_unlock(&fh->subscribe_lock);

 	return ret;
 }
 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,
 			   const struct v4l2_event_subscription *sub)
 {
 	struct v4l2_subscribed_event *sev;
 	unsigned long flags;
 	int i;

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

 	mutex_lock(&fh->subscribe_lock);

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

 	sev = v4l2_event_subscribed(fh, sub->type, sub->id);
 	if (sev != NULL) {
 		/* Remove any pending events for this subscription */
 		for (i = 0; i < sev->in_use; i++) {
 			list_del(&sev->events[sev_pos(sev, i)].list);
 			fh->navailable--;
 		}
 		list_del(&sev->list);
 	}

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

 	if (sev && sev->ops && sev->ops->del)
 		sev->ops->del(sev);

 	mutex_unlock(&fh->subscribe_lock);

 	kvfree(sev);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);

 int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, struct v4l2_fh *fh,
 				  struct v4l2_event_subscription *sub)
 {
 	return v4l2_event_unsubscribe(fh, sub);
 }
 EXPORT_SYMBOL_GPL(v4l2_event_subdev_unsubscribe);

 static void v4l2_event_src_replace(struct v4l2_event *old,
 				const struct v4l2_event *new)
 {
 	u32 old_changes = old->u.src_change.changes;

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

 static void v4l2_event_src_merge(const struct v4l2_event *old,
 				struct v4l2_event *new)
 {
 	new->u.src_change.changes |= old->u.src_change.changes;
 }

 static const struct v4l2_subscribed_event_ops v4l2_event_src_ch_ops = {
 	.replace = v4l2_event_src_replace,
 	.merge = v4l2_event_src_merge,
 };

 int v4l2_src_change_event_subscribe(struct v4l2_fh *fh,
 				const struct v4l2_event_subscription *sub)
 {
 	if (sub->type == V4L2_EVENT_SOURCE_CHANGE)
 		return v4l2_event_subscribe(fh, sub, 0, &v4l2_event_src_ch_ops);
 	return -EINVAL;
 }
 EXPORT_SYMBOL_GPL(v4l2_src_change_event_subscribe);

 int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd,
 		struct v4l2_fh *fh, struct v4l2_event_subscription *sub)
 {
 	return v4l2_src_change_event_subscribe(fh, sub);
 }
 EXPORT_SYMBOL_GPL(v4l2_src_change_event_subdev_subscribe);
	/*
	* v4l2-event.c
	*
	* V4L2 events.
	*
	* Copyright (C) 2009--2010 Nokia Corporation.
	*
	* Contact: Sakari Ailus <sakari.ailus@iki.fi>
	*
	* 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.
	*/

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

	#include <linux/mm.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/export.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->ops && sev->ops->replace) {
	sev->ops->replace(&kev->event, ev);
	copy_payload = false;
	}
	} else if (sev->ops && sev->ops->merge) {
	struct v4l2_kevent *second_oldest =
	sev->events + sev_pos(sev, 0);
	sev->ops->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;

	if (vdev == NULL)
	return;

	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);

	int v4l2_event_subscribe(struct v4l2_fh *fh,
	const struct v4l2_event_subscription *sub, unsigned elems,
	const struct v4l2_subscribed_event_ops *ops)
	{
	struct v4l2_subscribed_event sev, found_ev;
	unsigned long flags;
	unsigned i;
	int ret = 0;

	if (sub->type == V4L2_EVENT_ALL)
	return -EINVAL;

	if (elems < 1)
	elems = 1;

	sev = kvzalloc(struct_size(sev, events, 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->ops = ops;
	sev->elems = elems;

	mutex_lock(&fh->subscribe_lock);

	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
	found_ev = v4l2_event_subscribed(fh, sub->type, sub->id);
	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);

	if (found_ev) {
	/* Already listening */
	kvfree(sev);
	goto out_unlock;
	}

	if (sev->ops && sev->ops->add) {
	ret = sev->ops->add(sev, elems);
	if (ret) {
	kvfree(sev);
	goto out_unlock;
	}
	}

	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
	list_add(&sev->list, &fh->subscribed);
	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);

	out_unlock:
	mutex_unlock(&fh->subscribe_lock);

	return ret;
	}
	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,
	const struct v4l2_event_subscription *sub)
	{
	struct v4l2_subscribed_event *sev;
	unsigned long flags;
	int i;

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

	mutex_lock(&fh->subscribe_lock);

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

	sev = v4l2_event_subscribed(fh, sub->type, sub->id);
	if (sev != NULL) {
	/* Remove any pending events for this subscription */
	for (i = 0; i < sev->in_use; i++) {
	list_del(&sev->events[sev_pos(sev, i)].list);
	fh->navailable--;
	}
	list_del(&sev->list);
	}

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

	if (sev && sev->ops && sev->ops->del)
	sev->ops->del(sev);

	mutex_unlock(&fh->subscribe_lock);

	kvfree(sev);

	return 0;
	}
	EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);

	int v4l2_event_subdev_unsubscribe(struct v4l2_subdev sd, struct v4l2_fh fh,
	struct v4l2_event_subscription *sub)
	{
	return v4l2_event_unsubscribe(fh, sub);
	}
	EXPORT_SYMBOL_GPL(v4l2_event_subdev_unsubscribe);

	static void v4l2_event_src_replace(struct v4l2_event *old,
	const struct v4l2_event *new)
	{
	u32 old_changes = old->u.src_change.changes;

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

	static void v4l2_event_src_merge(const struct v4l2_event *old,
	struct v4l2_event *new)
	{
	new->u.src_change.changes \|= old->u.src_change.changes;
	}

	static const struct v4l2_subscribed_event_ops v4l2_event_src_ch_ops = {
	.replace = v4l2_event_src_replace,
	.merge = v4l2_event_src_merge,
	};

	int v4l2_src_change_event_subscribe(struct v4l2_fh *fh,
	const struct v4l2_event_subscription *sub)
	{
	if (sub->type == V4L2_EVENT_SOURCE_CHANGE)
	return v4l2_event_subscribe(fh, sub, 0, &v4l2_event_src_ch_ops);
	return -EINVAL;
	}
	EXPORT_SYMBOL_GPL(v4l2_src_change_event_subscribe);

	int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd,
	struct v4l2_fh fh, struct v4l2_event_subscription sub)
	{
	return v4l2_src_change_event_subscribe(fh, sub);
	}
	EXPORT_SYMBOL_GPL(v4l2_src_change_event_subdev_subscribe);