Re: [PATCH v5 03/10] media: rcar-vin: Create a group notifier

["Niklas Söderlund" <niklas.soderlund@ragnatech.se>]

Hi Jacopo,

Thanks for your work.

On 2018-05-29 10:48:01 +0200, Jacopo Mondi wrote:
> As CSI-2 subdevices are shared between several VIN instances, a shared
> notifier to collect the CSI-2 async subdevices is required. So far, the
> rcar-vin driver used the notifier of the last VIN instance to probe but
> with the forth-coming introduction of parallel input subdevices support
> in mc-compliant code path, each VIN may register its own notifier if any
> parallel subdevice is connected there.
> 
> To avoid registering a notifier twice (once for parallel subdev and one
> for the CSI-2 subdevs) create a group notifier, shared by all the VIN
> instances.
> 
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> 
> ---
> v3 -> v4:
> - Unregister and cleanup group notifier when un-registering the VIN
>   instance whose v4l2_dev the notifier is associated to.
> ---
>  drivers/media/platform/rcar-vin/rcar-core.c | 38 ++++++++++++++---------------
>  drivers/media/platform/rcar-vin/rcar-vin.h  |  5 ++--
>  2 files changed, 20 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
> index bcf02de..d3aadf3 100644
> --- a/drivers/media/platform/rcar-vin/rcar-core.c
> +++ b/drivers/media/platform/rcar-vin/rcar-core.c
> @@ -46,6 +46,8 @@
>   */
>  #define rvin_group_id_to_master(vin) ((vin) < 4 ? 0 : 4)
>  
> +#define v4l2_dev_to_vin(d)	container_of(d, struct rvin_dev, v4l2_dev)

I'm fine with this new macro but could you update the last 3 remaining 
call sites which after this patch still use the old macro 
notifier_to_vin()?  The old macro is with this patch misleading as it 
can't handle the group notifier. Or perhaps you could update the old 
macro and move it here?

#define notifier_to_vin(n) container_of((n)->v4l2_dev, struct rvin_dev, v4l2_dev)

I don't really care which macro you pick but I do think that there 
should only be one macro to go from a notifier to a rvin_dev instance 
and that it should be able to handle both the vin local and the group 
notifier.

The rest of this patch looks really nice.

> +
>  /* -----------------------------------------------------------------------------
>   * Media Controller link notification
>   */
> @@ -583,7 +585,7 @@ static int rvin_parallel_graph_init(struct rvin_dev *vin)
>  
>  static int rvin_group_notify_complete(struct v4l2_async_notifier *notifier)
>  {
> -	struct rvin_dev *vin = notifier_to_vin(notifier);
> +	struct rvin_dev *vin = v4l2_dev_to_vin(notifier->v4l2_dev);
>  	const struct rvin_group_route *route;
>  	unsigned int i;
>  	int ret;
> @@ -649,7 +651,7 @@ static void rvin_group_notify_unbind(struct v4l2_async_notifier *notifier,
>  				     struct v4l2_subdev *subdev,
>  				     struct v4l2_async_subdev *asd)
>  {
> -	struct rvin_dev *vin = notifier_to_vin(notifier);
> +	struct rvin_dev *vin = v4l2_dev_to_vin(notifier->v4l2_dev);
>  	unsigned int i;
>  
>  	for (i = 0; i < RCAR_VIN_NUM; i++)
> @@ -673,7 +675,7 @@ static int rvin_group_notify_bound(struct v4l2_async_notifier *notifier,
>  				   struct v4l2_subdev *subdev,
>  				   struct v4l2_async_subdev *asd)
>  {
> -	struct rvin_dev *vin = notifier_to_vin(notifier);
> +	struct rvin_dev *vin = v4l2_dev_to_vin(notifier->v4l2_dev);
>  	unsigned int i;
>  
>  	mutex_lock(&vin->group->lock);
> @@ -734,12 +736,6 @@ static int rvin_mc_parse_of_graph(struct rvin_dev *vin)
>  
>  	mutex_lock(&vin->group->lock);
>  
> -	/* If there already is a notifier something has gone wrong, bail out. */
> -	if (WARN_ON(vin->group->notifier)) {
> -		mutex_unlock(&vin->group->lock);
> -		return -EINVAL;
> -	}
> -
>  	/* If not all VIN's are registered don't register the notifier. */
>  	for (i = 0; i < RCAR_VIN_NUM; i++)
>  		if (vin->group->vin[i])
> @@ -751,19 +747,16 @@ static int rvin_mc_parse_of_graph(struct rvin_dev *vin)
>  	}
>  
>  	/*
> -	 * Have all VIN's look for subdevices. Some subdevices will overlap
> -	 * but the parser function can handle it, so each subdevice will
> -	 * only be registered once with the notifier.
> +	 * Have all VIN's look for CSI-2 subdevices. Some subdevices will
> +	 * overlap but the parser function can handle it, so each subdevice
> +	 * will only be registered once with the group notifier.
>  	 */
> -
> -	vin->group->notifier = &vin->notifier;
> -
>  	for (i = 0; i < RCAR_VIN_NUM; i++) {
>  		if (!vin->group->vin[i])
>  			continue;
>  
>  		ret = v4l2_async_notifier_parse_fwnode_endpoints_by_port(
> -				vin->group->vin[i]->dev, vin->group->notifier,
> +				vin->group->vin[i]->dev, &vin->group->notifier,
>  				sizeof(struct v4l2_async_subdev), 1,
>  				rvin_mc_parse_of_endpoint);
>  		if (ret) {
> @@ -774,9 +767,12 @@ static int rvin_mc_parse_of_graph(struct rvin_dev *vin)
>  
>  	mutex_unlock(&vin->group->lock);
>  
> -	vin->group->notifier->ops = &rvin_group_notify_ops;
> +	if (!vin->group->notifier.num_subdevs)
> +		return 0;
>  
> -	ret = v4l2_async_notifier_register(&vin->v4l2_dev, &vin->notifier);
> +	vin->group->notifier.ops = &rvin_group_notify_ops;
> +	ret = v4l2_async_notifier_register(&vin->v4l2_dev,
> +					   &vin->group->notifier);
>  	if (ret < 0) {
>  		vin_err(vin, "Notifier registration failed\n");
>  		return ret;
> @@ -1114,8 +1110,10 @@ static int rcar_vin_remove(struct platform_device *pdev)
>  
>  	if (vin->info->use_mc) {
>  		mutex_lock(&vin->group->lock);
> -		if (vin->group->notifier == &vin->notifier)
> -			vin->group->notifier = NULL;
> +		if (&vin->v4l2_dev == vin->group->notifier.v4l2_dev) {
> +			v4l2_async_notifier_unregister(&vin->group->notifier);
> +			v4l2_async_notifier_cleanup(&vin->group->notifier);
> +		}
>  		mutex_unlock(&vin->group->lock);
>  		rvin_group_put(vin);
>  	} else {
> diff --git a/drivers/media/platform/rcar-vin/rcar-vin.h b/drivers/media/platform/rcar-vin/rcar-vin.h
> index 755ac3c..ebb480f7 100644
> --- a/drivers/media/platform/rcar-vin/rcar-vin.h
> +++ b/drivers/media/platform/rcar-vin/rcar-vin.h
> @@ -225,8 +225,7 @@ struct rvin_dev {
>   *
>   * @lock:		protects the count, notifier, vin and csi members
>   * @count:		number of enabled VIN instances found in DT
> - * @notifier:		pointer to the notifier of a VIN which handles the
> - *			groups async sub-devices.
> + * @notifier:		group notifier for CSI-2 async subdevices
>   * @vin:		VIN instances which are part of the group
>   * @csi:		array of pairs of fwnode and subdev pointers
>   *			to all CSI-2 subdevices.
> @@ -238,7 +237,7 @@ struct rvin_group {
>  
>  	struct mutex lock;
>  	unsigned int count;
> -	struct v4l2_async_notifier *notifier;
> +	struct v4l2_async_notifier notifier;
>  	struct rvin_dev *vin[RCAR_VIN_NUM];
>  
>  	struct {
> -- 
> 2.7.4
> 

-- 
Regards,
Niklas Söderlund