Re: [PATCH 4/5] v4l2-event: Add v4l2_subscribed_event_ops
On Wednesday 02 November 2011 11:13:24 Hans de Goede wrote:
> Just like with ctrl events, drivers may want to get called back on
> listener add / remove for other event types too. Rather then special
> casing all of this in subscribe / unsubscribe event it is better to
> use ops for this.
>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> ---
> Documentation/video4linux/v4l2-framework.txt | 28 ++++++++++---
> drivers/media/video/ivtv/ivtv-ioctl.c | 2 +-
> drivers/media/video/omap3isp/ispccdc.c | 2 +-
> drivers/media/video/omap3isp/ispstat.c | 2 +-
> drivers/media/video/pwc/pwc-v4l.c | 2 +-
> drivers/media/video/v4l2-event.c | 54
> ++++++++++++++++++++----- drivers/media/video/vivi.c |
> 2 +-
> include/media/v4l2-event.h | 24 ++++++++---
> 8 files changed, 86 insertions(+), 30 deletions(-)
>
> diff --git a/Documentation/video4linux/v4l2-framework.txt
> b/Documentation/video4linux/v4l2-framework.txt index f8dcabf..16eb8af
> 100644
> --- a/Documentation/video4linux/v4l2-framework.txt
> +++ b/Documentation/video4linux/v4l2-framework.txt
> @@ -930,21 +930,35 @@ fast.
>
> Useful functions:
>
> -- v4l2_event_queue()
> +void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event
> *ev)
>
> Queue events to video device. The driver's only responsibility is to
> fill in the type and the data fields. The other fields will be filled in
> by V4L2.
>
> -- v4l2_event_subscribe()
> +int v4l2_event_subscribe(struct v4l2_fh *fh,
> + struct v4l2_event_subscription *sub, unsigned elems,
> + const struct v4l2_subscribed_event_ops *ops)
>
> The video_device->ioctl_ops->vidioc_subscribe_event must check the
> driver is able to produce events with specified event id. Then it calls -
> v4l2_event_subscribe() to subscribe the event. The last argument is the -
> size of the event queue for this event. If it is 0, then the framework -
> will fill in a default value (this depends on the event type).
> + v4l2_event_subscribe() to subscribe the event.
>
> -- v4l2_event_unsubscribe()
> + The elems argument is the size of the event queue for this event. If it
> is 0, + then the framework will fill in a default value (this depends on
> the event + type).
> +
> + The ops argument allows the driver to specify a number of callbacks:
> + * add: called when a new listener gets added (subscribing to the
> same + event twice will only cause this callback to get called
> once) + * del: called when a listener stops listening
> + * replace: replace event 'old' with event 'new'.
> + * merge: merge event 'old' into event 'new'.
> + All 4 callbacks are optional, if you don't want to specify any callbacks
> + the ops argument itself maybe NULL.
> +
> +int v4l2_event_unsubscribe(struct v4l2_fh *fh,
> + struct v4l2_event_subscription *sub)
>
> vidioc_unsubscribe_event in struct v4l2_ioctl_ops. A driver may use
> v4l2_event_unsubscribe() directly unless it wants to be involved in
> @@ -953,7 +967,7 @@ Useful functions:
> The special type V4L2_EVENT_ALL may be used to unsubscribe all events.
> The drivers may want to handle this in a special way.
>
> -- v4l2_event_pending()
> +int v4l2_event_pending(struct v4l2_fh *fh)
>
> Returns the number of pending events. Useful when implementing poll.
>
> diff --git a/drivers/media/video/ivtv/ivtv-ioctl.c
> b/drivers/media/video/ivtv/ivtv-ioctl.c index ecafa69..9aec8a0 100644
> --- a/drivers/media/video/ivtv/ivtv-ioctl.c
> +++ b/drivers/media/video/ivtv/ivtv-ioctl.c
> @@ -1456,7 +1456,7 @@ static int ivtv_subscribe_event(struct v4l2_fh *fh,
> struct v4l2_event_subscripti case V4L2_EVENT_VSYNC:
> case V4L2_EVENT_EOS:
> case V4L2_EVENT_CTRL:
> - return v4l2_event_subscribe(fh, sub, 0);
> + return v4l2_event_subscribe(fh, sub, 0, NULL);
> default:
> return -EINVAL;
> }
> diff --git a/drivers/media/video/omap3isp/ispccdc.c
> b/drivers/media/video/omap3isp/ispccdc.c index 40b141c..b6da736 100644
> --- a/drivers/media/video/omap3isp/ispccdc.c
> +++ b/drivers/media/video/omap3isp/ispccdc.c
> @@ -1700,7 +1700,7 @@ static int ccdc_subscribe_event(struct v4l2_subdev
> *sd, struct v4l2_fh *fh, if (sub->id != 0)
> return -EINVAL;
>
> - return v4l2_event_subscribe(fh, sub, OMAP3ISP_CCDC_NEVENTS);
> + return v4l2_event_subscribe(fh, sub, OMAP3ISP_CCDC_NEVENTS, NULL);
> }
>
> static int ccdc_unsubscribe_event(struct v4l2_subdev *sd, struct v4l2_fh
> *fh, diff --git a/drivers/media/video/omap3isp/ispstat.c
> b/drivers/media/video/omap3isp/ispstat.c index 8080659..4f337a2 100644
> --- a/drivers/media/video/omap3isp/ispstat.c
> +++ b/drivers/media/video/omap3isp/ispstat.c
> @@ -1049,7 +1049,7 @@ int omap3isp_stat_subscribe_event(struct v4l2_subdev
> *subdev, if (sub->type != stat->event_type)
> return -EINVAL;
>
> - return v4l2_event_subscribe(fh, sub, STAT_NEVENTS);
> + return v4l2_event_subscribe(fh, sub, STAT_NEVENTS, NULL);
> }
>
> int omap3isp_stat_unsubscribe_event(struct v4l2_subdev *subdev,
> diff --git a/drivers/media/video/pwc/pwc-v4l.c
> b/drivers/media/video/pwc/pwc-v4l.c index 68e1323..7f159bf 100644
> --- a/drivers/media/video/pwc/pwc-v4l.c
> +++ b/drivers/media/video/pwc/pwc-v4l.c
> @@ -1138,7 +1138,7 @@ static int pwc_subscribe_event(struct v4l2_fh *fh,
> {
> switch (sub->type) {
> case V4L2_EVENT_CTRL:
> - return v4l2_event_subscribe(fh, sub, 0);
> + return v4l2_event_subscribe(fh, sub, 0, NULL);
> default:
> return -EINVAL;
> }
> diff --git a/drivers/media/video/v4l2-event.c
> b/drivers/media/video/v4l2-event.c index 3d93251..aad2a79 100644
> --- a/drivers/media/video/v4l2-event.c
> +++ b/drivers/media/video/v4l2-event.c
> @@ -119,6 +119,14 @@ static void __v4l2_event_queue_fh(struct v4l2_fh *fh,
> const struct v4l2_event *e if (sev == NULL)
> return;
>
> + /*
> + * If the event has been added to the fh->subscribed list, but its
> + * add op has not completed yet elems will be 0, treat this as
> + * not being subscribed.
> + */
> + if (!sev->elems)
> + return;
> +
> /* Increase event sequence number on fh. */
> fh->sequence++;
>
> @@ -131,14 +139,14 @@ static void __v4l2_event_queue_fh(struct v4l2_fh *fh,
> const struct v4l2_event *e sev->first = sev_pos(sev, 1);
> fh->navailable--;
> if (sev->elems == 1) {
> - if (sev->replace) {
> - sev->replace(&kev->event, ev);
> + if (sev->ops && sev->ops->replace) {
> + sev->ops->replace(&kev->event, ev);
> copy_payload = false;
> }
> - } else if (sev->merge) {
> + } else if (sev->ops && sev->ops->merge) {
> struct v4l2_kevent *second_oldest =
> sev->events + sev_pos(sev, 0);
> - sev->merge(&kev->event, &second_oldest->event);
> + sev->ops->merge(&kev->event, &second_oldest->event);
> }
> }
>
> @@ -207,8 +215,14 @@ static void ctrls_merge(const struct v4l2_event *old,
> struct v4l2_event *new) new->u.ctrl.changes |= old->u.ctrl.changes;
> }
>
> +static const struct v4l2_subscribed_event_ops ctrl_ops = {
> + .replace = ctrls_replace,
> + .merge = ctrls_merge,
> +};
> +
> int v4l2_event_subscribe(struct v4l2_fh *fh,
> - struct v4l2_event_subscription *sub, unsigned elems)
> + struct v4l2_event_subscription *sub, unsigned elems,
> + const struct v4l2_subscribed_event_ops *ops)
> {
> struct v4l2_subscribed_event *sev, *found_ev;
> struct v4l2_ctrl *ctrl = NULL;
> @@ -235,10 +249,9 @@ int v4l2_event_subscribe(struct v4l2_fh *fh,
> sev->id = sub->id;
> sev->flags = sub->flags;
> sev->fh = fh;
> - sev->elems = elems;
> + sev->ops = ops;
> if (ctrl) {
> - sev->replace = ctrls_replace;
> - sev->merge = ctrls_merge;
> + sev->ops = &ctrl_ops;
> }
>
> spin_lock_irqsave(&fh->vdev->fh_lock, flags);
> @@ -247,12 +260,27 @@ int v4l2_event_subscribe(struct v4l2_fh *fh,
> list_add(&sev->list, &fh->subscribed);
> spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
>
> - /* v4l2_ctrl_add_event uses a mutex, so do this outside the spin lock
*/
> - if (found_ev)
> + if (found_ev) {
> kfree(sev);
> - else if (ctrl)
> + return 0; /* Already listening */
> + }
> +
> + if (sev->ops && sev->ops->add) {
> + int ret = sev->ops->add(sev);
> + if (ret) {
> + sev->ops = NULL;
> + v4l2_event_unsubscribe(fh, sub);
> + return ret;
> + }
> + }
> +
> + /* v4l2_ctrl_add_event uses a mutex, so do this outside the spin lock
*/
> + if (ctrl)
> v4l2_ctrl_add_event(ctrl, sev);
>
> + /* Mark as ready for use */
> + sev->elems = elems;
> +
> return 0;
> }
> EXPORT_SYMBOL_GPL(v4l2_event_subscribe);
> @@ -305,6 +333,10 @@ int v4l2_event_unsubscribe(struct v4l2_fh *fh,
> }
>
> spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
> +
> + if (sev && sev->ops && sev->ops->del)
> + sev->ops->del(sev);
> +
> if (sev && sev->type == V4L2_EVENT_CTRL) {
> struct v4l2_ctrl *ctrl = v4l2_ctrl_find(fh->ctrl_handler, sev-
>id);
>
> diff --git a/drivers/media/video/vivi.c b/drivers/media/video/vivi.c
> index c25787d..74ebbad 100644
> --- a/drivers/media/video/vivi.c
> +++ b/drivers/media/video/vivi.c
> @@ -1013,7 +1013,7 @@ static int vidioc_subscribe_event(struct v4l2_fh *fh,
> {
> switch (sub->type) {
> case V4L2_EVENT_CTRL:
> - return v4l2_event_subscribe(fh, sub, 0);
> + return v4l2_event_subscribe(fh, sub, 0, NULL);
> default:
> return -EINVAL;
> }
> diff --git a/include/media/v4l2-event.h b/include/media/v4l2-event.h
> index 5f14e88..88fa9a1 100644
> --- a/include/media/v4l2-event.h
> +++ b/include/media/v4l2-event.h
> @@ -78,6 +78,19 @@ struct v4l2_kevent {
> struct v4l2_event event;
> };
>
> +/** struct v4l2_subscribed_event_ops - Subscribed event operations.
> + * @add: Optional callback, called when a new listener is added
> + * @del: Optional callback, called when a listener stops listening
> + * @replace: Optional callback that can replace event 'old' with
event
> 'new'. + * @merge: Optional callback that can merge event 'old' into
> event 'new'. + */
> +struct v4l2_subscribed_event_ops {
> + int (*add)(struct v4l2_subscribed_event *sev);
> + void (*del)(struct v4l2_subscribed_event *sev);
> + void (*replace)(struct v4l2_event *old, const struct v4l2_event *new);
> + void (*merge)(const struct v4l2_event *old, struct v4l2_event *new);
> +};
> +
> /** struct v4l2_subscribed_event - Internal struct representing a
> subscribed event. * @list: List node for the v4l2_fh->subscribed list.
> * @type: Event type.
> @@ -85,8 +98,7 @@ struct v4l2_kevent {
> * @flags: Copy of v4l2_event_subscription->flags.
> * @fh: Filehandle that subscribed to this event.
> * @node: List node that hooks into the object's event list (if there is
> one). - * @replace: Optional callback that can replace event 'old' with
> event 'new'. - * @merge: Optional callback that can merge event 'old'
> into event 'new'. + * @ops: v4l2_subscribed_event_ops
> * @elems: The number of elements in the events array.
> * @first: The index of the events containing the oldest available event.
> * @in_use: The number of queued events.
> @@ -99,10 +111,7 @@ struct v4l2_subscribed_event {
> u32 flags;
> struct v4l2_fh *fh;
> struct list_head node;
> - void (*replace)(struct v4l2_event *old,
> - const struct v4l2_event *new);
> - void (*merge)(const struct v4l2_event *old,
> - struct v4l2_event *new);
> + const struct v4l2_subscribed_event_ops *ops;
> unsigned elems;
> unsigned first;
> unsigned in_use;
> @@ -115,7 +124,8 @@ void v4l2_event_queue(struct video_device *vdev, const
> struct v4l2_event *ev); void v4l2_event_queue_fh(struct v4l2_fh *fh, 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, unsigned elems);
> + struct v4l2_event_subscription *sub, unsigned elems,
> + const struct v4l2_subscribed_event_ops *ops);
> int v4l2_event_unsubscribe(struct v4l2_fh *fh,
> struct v4l2_event_subscription *sub);
> void v4l2_event_unsubscribe_all(struct v4l2_fh *fh);
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