Re: [PATCH v2 03/30] media: entity: Walk the graph based on pads

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Niklas,

Thank you for the patch.

On Fri, Nov 02, 2018 at 12:31:17AM +0100, Niklas Söderlund wrote:
> From: Sakari Ailus <sakari.ailus@linux.intel.com>
> 
> Instead of iterating over graph entities during the walk, iterate the pads
> through which the entity was first reached. This is required in order to
> make the entity pipeline pad-based rather than entity based.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> ---
>  Documentation/media/kapi/mc-core.rst          |  7 ++-
>  drivers/media/media-entity.c                  | 46 ++++++++++--------
>  drivers/media/platform/exynos4-is/media-dev.c | 20 ++++----
>  drivers/media/platform/omap3isp/ispvideo.c    | 17 +++----
>  drivers/media/platform/vsp1/vsp1_video.c      | 12 ++---
>  drivers/media/platform/xilinx/xilinx-dma.c    | 12 ++---
>  drivers/media/v4l2-core/v4l2-mc.c             | 25 +++++-----
>  .../staging/media/davinci_vpfe/vpfe_video.c   | 47 ++++++++++---------
>  drivers/staging/media/omap4iss/iss_video.c    | 34 +++++++-------
>  include/media/media-entity.h                  |  7 +--
>  10 files changed, 122 insertions(+), 105 deletions(-)

[snip]

> diff --git a/drivers/media/platform/exynos4-is/media-dev.c b/drivers/media/platform/exynos4-is/media-dev.c
> index 51d2a571c06db6a3..5813639c63b56a2c 100644
> --- a/drivers/media/platform/exynos4-is/media-dev.c
> +++ b/drivers/media/platform/exynos4-is/media-dev.c
> @@ -1135,7 +1135,7 @@ static int __fimc_md_modify_pipeline(struct media_entity *entity, bool enable)
>  static int __fimc_md_modify_pipelines(struct media_entity *entity, bool enable,
>  				      struct media_graph *graph)
>  {
> -	struct media_entity *entity_err = entity;
> +	struct media_pad *pad, *pad_err = entity->pads;
>  	int ret;
>  
>  	/*
> @@ -1144,13 +1144,13 @@ static int __fimc_md_modify_pipelines(struct media_entity *entity, bool enable,
>  	 * through active links. This is needed as we cannot power on/off the
>  	 * subdevs in random order.
>  	 */
> -	media_graph_walk_start(graph, entity->pads);
> +	media_graph_walk_start(graph, pad_err);

I would keep entity->pads here as we're not dealing with an error path.

>  
> -	while ((entity = media_graph_walk_next(graph))) {
> -		if (!is_media_entity_v4l2_video_device(entity))
> +	while ((pad = media_graph_walk_next(graph))) {
> +		if (!is_media_entity_v4l2_video_device(pad->entity))
>  			continue;
>  
> -		ret  = __fimc_md_modify_pipeline(entity, enable);
> +		ret  = __fimc_md_modify_pipeline(pad->entity, enable);
>  
>  		if (ret < 0)
>  			goto err;
> @@ -1159,15 +1159,15 @@ static int __fimc_md_modify_pipelines(struct media_entity *entity, bool enable,
>  	return 0;
>  
>  err:
> -	media_graph_walk_start(graph, entity_err->pads);
> +	media_graph_walk_start(graph, pad_err);
>  
> -	while ((entity_err = media_graph_walk_next(graph))) {
> -		if (!is_media_entity_v4l2_video_device(entity_err))
> +	while ((pad_err = media_graph_walk_next(graph))) {
> +		if (!is_media_entity_v4l2_video_device(pad_err->entity))
>  			continue;
>  
> -		__fimc_md_modify_pipeline(entity_err, !enable);
> +		__fimc_md_modify_pipeline(pad_err->entity, !enable);
>  
> -		if (entity_err == entity)
> +		if (pad_err == pad)
>  			break;
>  	}
>  

[snip]

> diff --git a/drivers/media/v4l2-core/v4l2-mc.c b/drivers/media/v4l2-core/v4l2-mc.c
> index 9ed480fe5b6e4762..98edd47b2f0ae747 100644
> --- a/drivers/media/v4l2-core/v4l2-mc.c
> +++ b/drivers/media/v4l2-core/v4l2-mc.c
> @@ -339,13 +339,14 @@ EXPORT_SYMBOL_GPL(v4l_vb2q_enable_media_source);
>  static int pipeline_pm_use_count(struct media_entity *entity,
>  	struct media_graph *graph)
>  {
> +	struct media_pad *pad;
>  	int use = 0;
>  
>  	media_graph_walk_start(graph, entity->pads);
>  
> -	while ((entity = media_graph_walk_next(graph))) {
> -		if (is_media_entity_v4l2_video_device(entity))
> -			use += entity->use_count;
> +	while ((pad = media_graph_walk_next(graph))) {
> +		if (is_media_entity_v4l2_video_device(pad->entity))
> +			use += pad->entity->use_count;
>  	}
>  
>  	return use;
> @@ -398,7 +399,7 @@ static int pipeline_pm_power_one(struct media_entity *entity, int change)
>  static int pipeline_pm_power(struct media_entity *entity, int change,
>  	struct media_graph *graph)
>  {
> -	struct media_entity *first = entity;
> +	struct media_pad *tmp_pad, *pad;

How about pad_err instead of tmp_pad, like in the exynos driver ? Or
possible first_pad to retain the "first" name ?

>  	int ret = 0;
>  
>  	if (!change)
> @@ -406,19 +407,19 @@ static int pipeline_pm_power(struct media_entity *entity, int change,
>  
>  	media_graph_walk_start(graph, entity->pads);
>  
> -	while (!ret && (entity = media_graph_walk_next(graph)))
> -		if (is_media_entity_v4l2_subdev(entity))
> -			ret = pipeline_pm_power_one(entity, change);
> +	while (!ret && (pad = media_graph_walk_next(graph)))
> +		if (is_media_entity_v4l2_subdev(pad->entity))
> +			ret = pipeline_pm_power_one(pad->entity, change);
>  
>  	if (!ret)
>  		return ret;
>  
> -	media_graph_walk_start(graph, first->pads);
> +	media_graph_walk_start(graph, entity->pads);
>  
> -	while ((first = media_graph_walk_next(graph))
> -	       && first != entity)
> -		if (is_media_entity_v4l2_subdev(first))
> -			pipeline_pm_power_one(first, -change);
> +	while ((tmp_pad = media_graph_walk_next(graph))
> +	       && tmp_pad != pad)
> +		if (is_media_entity_v4l2_subdev(tmp_pad->entity))
> +			pipeline_pm_power_one(tmp_pad->entity, -change);
>  
>  	return ret;
>  }

[snip]

> diff --git a/include/media/media-entity.h b/include/media/media-entity.h
> index 99c7606f01317741..cde6350d752bb0ae 100644
> --- a/include/media/media-entity.h
> +++ b/include/media/media-entity.h
> @@ -952,10 +952,11 @@ void media_graph_walk_start(struct media_graph *graph, struct media_pad *pad);
>   * The graph structure must have been previously initialized with a call to
>   * media_graph_walk_start().
>   *
> - * Return: returns the next entity in the graph or %NULL if the whole graph
> - * have been traversed.
> + * Return: returns the next pad in the graph or %NULL if the whole
> + * graph have been traversed. The pad which is returned is the pad

s/have been/has/been/
s/The pad which is returned/The returned pad/

> + * through which a new entity is reached when parsing the graph.

through which the entity was reached when walking the graph.

With these addressed,

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

>   */
> -struct media_entity *media_graph_walk_next(struct media_graph *graph);
> +struct media_pad *media_graph_walk_next(struct media_graph *graph);
>  
>  /**
>   * media_pipeline_start - Mark a pipeline as streaming

-- 
Regards,

Laurent Pinchart