Reviewed-by: Hans Verkuil <hverkuil@xxxxxxxxx>
On Monday 22 February 2010 16:51:35 Sakari Ailus wrote:
> 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 <sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx>
>
>
> Header from folded patch 'event-dq-block':
>
> V4L: Events: Blocking dqevent
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/media/video/Makefile | 3 +-
> drivers/media/video/v4l2-event.c | 294 ++++++++++++++++++++++++++++++++++++++
> drivers/media/video/v4l2-fh.c | 5 +
> include/media/v4l2-event.h | 67 +++++++++
> include/media/v4l2-fh.h | 2 +
> 5 files changed, 370 insertions(+), 1 deletions(-)
> create mode 100644 drivers/media/video/v4l2-event.c
> create mode 100644 include/media/v4l2-event.h
>
> diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
> index 14bf69a..b84abfe 100644
> --- a/drivers/media/video/Makefile
> +++ b/drivers/media/video/Makefile
> @@ -10,7 +10,8 @@ stkwebcam-objs := stk-webcam.o stk-sensor.o
>
> omap2cam-objs := omap24xxcam.o omap24xxcam-dma.o
>
> -videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o
> +videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \
> + v4l2-event.o
>
> # V4L2 core modules
>
> diff --git a/drivers/media/video/v4l2-event.c b/drivers/media/video/v4l2-event.c
> new file mode 100644
> index 0000000..d65df06
> --- /dev/null
> +++ b/drivers/media/video/v4l2-event.c
> @@ -0,0 +1,294 @@
> +/*
> + * drivers/media/video/v4l2-event.c
> + *
> + * V4L2 events.
> + *
> + * Copyright (C) 2009 Nokia Corporation.
> + *
> + * Contact: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx>
> + *
> + * 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>
> +
> +int v4l2_event_init(struct v4l2_fh *fh)
> +{
> + if (fh->events != NULL) {
> + WARN_ON(1);
> + return 0;
> + }
> +
> + 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);
> diff --git a/drivers/media/video/v4l2-fh.c b/drivers/media/video/v4l2-fh.c
> index c707930..713f5a0 100644
> --- a/drivers/media/video/v4l2-fh.c
> +++ b/drivers/media/video/v4l2-fh.c
> @@ -25,12 +25,15 @@
> #include <linux/bitops.h>
> #include <media/v4l2-dev.h>
> #include <media/v4l2-fh.h>
> +#include <media/v4l2-event.h>
> +#include <media/v4l2-ioctl.h>
>
> void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
> {
> fh->vdev = vdev;
> INIT_LIST_HEAD(&fh->list);
> set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
> + v4l2_event_init(fh);
> }
> EXPORT_SYMBOL_GPL(v4l2_fh_init);
>
> @@ -60,5 +63,7 @@ void v4l2_fh_exit(struct v4l2_fh *fh)
> return;
>
> fh->vdev = NULL;
> +
> + v4l2_event_free(fh);
> }
> EXPORT_SYMBOL_GPL(v4l2_fh_exit);
> diff --git a/include/media/v4l2-event.h b/include/media/v4l2-event.h
> new file mode 100644
> index 0000000..7dad9f8
> --- /dev/null
> +++ b/include/media/v4l2-event.h
> @@ -0,0 +1,67 @@
> +/*
> + * include/media/v4l2-event.h
> + *
> + * V4L2 events.
> + *
> + * Copyright (C) 2009 Nokia Corporation.
> + *
> + * Contact: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx>
> + *
> + * 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
> + */
> +
> +#ifndef V4L2_EVENT_H
> +#define V4L2_EVENT_H
> +
> +#include <linux/types.h>
> +#include <linux/videodev2.h>
> +#include <linux/wait.h>
> +
> +struct v4l2_fh;
> +struct video_device;
> +
> +struct v4l2_kevent {
> + struct list_head list;
> + struct v4l2_event event;
> +};
> +
> +struct v4l2_subscribed_event {
> + struct list_head list;
> + u32 type;
> +};
> +
> +struct v4l2_events {
> + wait_queue_head_t wait;
> + struct list_head subscribed; /* Subscribed events */
> + struct list_head free; /* Events ready for use */
> + struct list_head available; /* Dequeueable event */
> + unsigned int navailable;
> + unsigned int nallocated; /* Number of allocated events */
> + u32 sequence;
> +};
> +
> +int v4l2_event_init(struct v4l2_fh *fh);
> +int v4l2_event_alloc(struct v4l2_fh *fh, unsigned int n);
> +void v4l2_event_free(struct v4l2_fh *fh);
> +int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
> + int nonblocking);
> +void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev);
> +int v4l2_event_pending(struct v4l2_fh *fh);
> +int v4l2_event_subscribe(struct v4l2_fh *fh,
> + struct v4l2_event_subscription *sub);
> +int v4l2_event_unsubscribe(struct v4l2_fh *fh,
> + struct v4l2_event_subscription *sub);
> +
> +#endif /* V4L2_EVENT_H */
> diff --git a/include/media/v4l2-fh.h b/include/media/v4l2-fh.h
> index 6b486aa..6c9df56 100644
> --- a/include/media/v4l2-fh.h
> +++ b/include/media/v4l2-fh.h
> @@ -28,10 +28,12 @@
> #include <linux/list.h>
>
> struct video_device;
> +struct v4l2_events;
>
> struct v4l2_fh {
> struct list_head list;
> struct video_device *vdev;
> + struct v4l2_events *events; /* events, pending and subscribed */
> };
>
> void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
>
--
Hans Verkuil - video4linux developer - sponsored by TANDBERG
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