Re: [PATCH 23/31] media: au0828 implement enable_source and disable_source handlers

From: Mauro Carvalho Chehab
Date: Thu Jan 28 2016 - 11:43:55 EST


Em Wed, 6 Jan 2016 13:27:12 -0700
Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> escreveu:

> Implements enable_source and disable_source handlers for other
> drivers (v4l2-core, dvb-core, and ALSA) to use to check for
> tuner connected to the decoder and activate the link if tuner
> is free, and deactivate and free the tuner when it is no longer
> needed.
>
> Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
> ---
> drivers/media/usb/au0828/au0828-core.c | 148 +++++++++++++++++++++++++++++++++
> drivers/media/usb/au0828/au0828.h | 2 +
> 2 files changed, 150 insertions(+)
>
> diff --git a/drivers/media/usb/au0828/au0828-core.c b/drivers/media/usb/au0828/au0828-core.c
> index a15a61a..f8d2db3 100644
> --- a/drivers/media/usb/au0828/au0828-core.c
> +++ b/drivers/media/usb/au0828/au0828-core.c
> @@ -370,6 +370,150 @@ static int au0828_create_media_graph(struct au0828_dev *dev)
> return 0;
> }
>
> +static int au0828_enable_source(struct media_entity *entity,
> + struct media_pipeline *pipe)
> +{

The best would be to put those enable source stuff at the core, in a way
that other drivers could share it.

Not sure about the implementation, as this requires testing ;)
Did you consider the cases where the source connector is S-Video
or Composite?

> +#ifdef CONFIG_MEDIA_CONTROLLER
> + struct media_entity *source;
> + struct media_entity *sink;
> + struct media_link *link, *found_link = NULL;
> + int ret = 0;
> + struct media_device *mdev = entity->graph_obj.mdev;
> + struct au0828_dev *dev;
> +
> + if (!mdev)
> + return -ENODEV;
> +
> + /* for Audio and Video entities, source is the decoder */
> + mutex_lock(&mdev->graph_mutex);
> +
> + dev = mdev->source_priv;
> + if (!dev->tuner || !dev->decoder) {
> + ret = -ENODEV;
> + goto end;
> + }
> +
> + /*
> + * For Audio and V4L2 entity, find the link to which decoder
> + * is the sink. Look for an active link between decoder and
> + * tuner, if one exists, nothing to do. If not, look for any
> + * active links between tuner and any other entity. If one
> + * exists, tuner is busy. If tuner is free, setup link and
> + * start pipeline from source (tuner).
> + * For DVB FE entity, the source for the link is the tuner.
> + * Check if tuner is available and setup link and start
> + * pipeline.
> + */
> + if (entity->function != MEDIA_ENT_F_DTV_DEMOD)
> + sink = dev->decoder;
> + else
> + sink = entity;
> +
> + /* Is an active link between sink and tuner */
> + if (dev->active_link) {
> + if (dev->active_link->sink->entity == sink &&
> + dev->active_link->source->entity == dev->tuner) {
> + ret = 0;
> + goto end;
> + } else {
> + ret = -EBUSY;
> + goto end;
> + }
> + }
> +
> + list_for_each_entry(link, &sink->links, list) {
> + /* Check sink, and source */
> + if (link->sink->entity == sink &&
> + link->source->entity == dev->tuner) {
> + found_link = link;
> + break;
> + }
> + }
> +
> + if (!found_link) {
> + ret = -ENODEV;
> + goto end;
> + }
> +
> + /* activate link between source and sink and start pipeline */
> + source = found_link->source->entity;
> + ret = __media_entity_setup_link(found_link, MEDIA_LNK_FL_ENABLED);
> + if (ret) {
> + pr_err(
> + "Activate tuner link %s->%s. Error %d\n",
> + source->name, sink->name, ret);
> + goto end;
> + }
> +
> + ret = __media_entity_pipeline_start(entity, pipe);
> + if (ret) {
> + pr_err("Start Pipeline: %s->%s Error %d\n",
> + source->name, entity->name, ret);
> + ret = __media_entity_setup_link(found_link, 0);
> + pr_err("Deactive link Error %d\n", ret);
> + goto end;
> + }
> + /*
> + * save active link and active link owner to avoid audio
> + * deactivating video owned link from disable_source and
> + * vice versa
> + */
> + dev->active_link = found_link;
> + dev->active_link_owner = entity;
> +end:
> + mutex_unlock(&mdev->graph_mutex);
> + pr_debug("au0828_enable_source() end %s %d %d\n",
> + entity->name, entity->function, ret);
> + return ret;
> +#endif
> + return 0;
> +}
> +
> +static void au0828_disable_source(struct media_entity *entity)
> +{
> +#ifdef CONFIG_MEDIA_CONTROLLER
> + struct media_entity *sink;
> + int ret = 0;
> + struct media_device *mdev = entity->graph_obj.mdev;
> + struct au0828_dev *dev;
> +
> + if (!mdev)
> + return;
> +
> + mutex_lock(&mdev->graph_mutex);
> + dev = mdev->source_priv;
> + if (!dev->tuner || !dev->decoder || !dev->active_link) {
> + ret = -ENODEV;
> + goto end;
> + }
> +
> + if (entity->function != MEDIA_ENT_F_DTV_DEMOD)
> + sink = dev->decoder;
> + else
> + sink = entity;
> +
> + /* link is active - stop pipeline from source (tuner) */
> + if (dev->active_link && dev->active_link->sink->entity == sink &&
> + dev->active_link->source->entity == dev->tuner) {
> + /*
> + * prevent video from deactivating link when audio
> + * has active pipeline
> + */
> + if (dev->active_link_owner != entity)
> + goto end;
> + __media_entity_pipeline_stop(entity);
> + ret = __media_entity_setup_link(dev->active_link, 0);
> + if (ret)
> + pr_err("Deactive link Error %d\n", ret);
> + dev->active_link = NULL;
> + dev->active_link_owner = NULL;
> + }
> +
> +end:
> + mutex_unlock(&mdev->graph_mutex);
> +#endif
> +}
> +
> static int au0828_media_device_register(struct au0828_dev *dev,
> struct usb_device *udev)
> {
> @@ -400,6 +544,10 @@ static int au0828_media_device_register(struct au0828_dev *dev,
> ret);
> return ret;
> }
> + /* set enable_source */
> + dev->media_dev->source_priv = (void *) dev;
> + dev->media_dev->enable_source = au0828_enable_source;
> + dev->media_dev->disable_source = au0828_disable_source;
> #endif
> return 0;
> }
> diff --git a/drivers/media/usb/au0828/au0828.h b/drivers/media/usb/au0828/au0828.h
> index cfb6d58..3707664 100644
> --- a/drivers/media/usb/au0828/au0828.h
> +++ b/drivers/media/usb/au0828/au0828.h
> @@ -289,6 +289,8 @@ struct au0828_dev {
> bool vdev_linked;
> bool vbi_linked;
> bool audio_capture_linked;
> + struct media_link *active_link;
> + struct media_entity *active_link_owner;
> #endif
> };
>