From c3b5b0241f620a356c97d8f43343e721c718806d Mon Sep 17 00:00:00 2001 From: Sakari Ailus Date: Mon, 1 Mar 2010 05:14:18 -0300 Subject: V4L/DVB: V4L: Events: Add backend Add event handling backend to V4L2. The backend handles event subscription and delivery to file handles. Event subscriptions are based on file handle. Events may be delivered to all subscribed file handles on a device independent of where they originate from. Signed-off-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/v4l2-event.c | 290 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 290 insertions(+) create mode 100644 drivers/media/video/v4l2-event.c (limited to 'drivers/media/video/v4l2-event.c') diff --git a/drivers/media/video/v4l2-event.c b/drivers/media/video/v4l2-event.c new file mode 100644 index 000000000000..170e40f56cf7 --- /dev/null +++ b/drivers/media/video/v4l2-event.c @@ -0,0 +1,290 @@ +/* + * v4l2-event.c + * + * V4L2 events. + * + * Copyright (C) 2009--2010 Nokia Corporation. + * + * Contact: Sakari Ailus + * + * 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 +#include +#include + +#include +#include + +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; +} + +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; +} + +/* 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; + + WARN_ON(!spin_is_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(×tamp); + + 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); -- cgit v1.2.3 From f3cd385a9c95e1ea90e886448ab1e83ee2fc7e51 Mon Sep 17 00:00:00 2001 From: Sakari Ailus Date: Mon, 3 May 2010 12:42:46 -0300 Subject: V4L/DVB: V4L: Events: Replace bad WARN_ON() with assert_spin_locked() spin_is_locked() always returns zero when spinlock debugging is disabled on a single CPU machine. Replace WARN_ON() with assert_spin_locked(). Thanks to Laurent Pinchart for spotting this! Signed-off-by: Sakari Ailus Acked-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/v4l2-event.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/media/video/v4l2-event.c') diff --git a/drivers/media/video/v4l2-event.c b/drivers/media/video/v4l2-event.c index 170e40f56cf7..91bb1c823992 100644 --- a/drivers/media/video/v4l2-event.c +++ b/drivers/media/video/v4l2-event.c @@ -152,7 +152,7 @@ static struct v4l2_subscribed_event *v4l2_event_subscribed( struct v4l2_events *events = fh->events; struct v4l2_subscribed_event *sev; - WARN_ON(!spin_is_locked(&fh->vdev->fh_lock)); + assert_spin_locked(&fh->vdev->fh_lock); list_for_each_entry(sev, &events->subscribed, list) { if (sev->type == type) -- cgit v1.2.3 From 0a4f8d0798c834472b9d8d50df32b62c733009fd Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Sun, 2 May 2010 14:32:43 -0300 Subject: V4L/DVB: event: Export the v4l2_event_init and v4l2_event_dequeue functions Signed-off-by: Laurent Pinchart Acked-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/v4l2-event.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/media/video/v4l2-event.c') diff --git a/drivers/media/video/v4l2-event.c b/drivers/media/video/v4l2-event.c index 91bb1c823992..de74ce07b5e2 100644 --- a/drivers/media/video/v4l2-event.c +++ b/drivers/media/video/v4l2-event.c @@ -45,6 +45,7 @@ int v4l2_event_init(struct v4l2_fh *fh) return 0; } +EXPORT_SYMBOL_GPL(v4l2_event_init); int v4l2_event_alloc(struct v4l2_fh *fh, unsigned int n) { @@ -144,6 +145,7 @@ int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event, return ret; } +EXPORT_SYMBOL_GPL(v4l2_event_dequeue); /* Caller must hold fh->event->lock! */ static struct v4l2_subscribed_event *v4l2_event_subscribed( -- cgit v1.2.3