Date:   Mon, 12 Jun 2017 11:50:45 +0200
From:   Hans Verkuil <hverkuil@...all.nl>
To:     Helen Koike <helen.koike@...labora.com>,
        linux-media@...r.kernel.org,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-kernel@...r.kernel.org
Cc:     jgebben@...eaurora.org, mchehab@....samsung.com,
        Sakari Ailus <sakari.ailus@....fi>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>
Subject: Re: [RFC PATCH v3 05/11] [media] vimc: common: Add vimc_link_validate

On 06/03/2017 04:58 AM, Helen Koike wrote:
> All links will be checked in the same way. Adding a helper function for
> that
> 
> Signed-off-by: Helen Koike <helen.koike@...labora.com>
> 
> ---
> 
> Changes in v3:
> [media] vimc: common: Add vimc_link_validate
> 	- this is a new patch in the series
> 
> Changes in v2: None
> 
> 
> ---
>   drivers/media/platform/vimc/vimc-capture.c |  78 +++---------------
>   drivers/media/platform/vimc/vimc-common.c  | 124 ++++++++++++++++++++++++++++-
>   drivers/media/platform/vimc/vimc-common.h  |  14 ++++
>   3 files changed, 148 insertions(+), 68 deletions(-)
> 
> diff --git a/drivers/media/platform/vimc/vimc-capture.c b/drivers/media/platform/vimc/vimc-capture.c
> index 93f6a09..5bdecd1 100644
> --- a/drivers/media/platform/vimc/vimc-capture.c
> +++ b/drivers/media/platform/vimc/vimc-capture.c
> @@ -64,6 +64,15 @@ static int vimc_cap_querycap(struct file *file, void *priv,
>   	return 0;
>   }
>   
> +static void vimc_cap_get_format(struct vimc_ent_device *ved,
> +				struct v4l2_pix_format *fmt)
> +{
> +	struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device,
> +						    ved);
> +
> +	*fmt = vcap->format;
> +}
> +
>   static int vimc_cap_fmt_vid_cap(struct file *file, void *priv,
>   				  struct v4l2_format *f)
>   {
> @@ -231,74 +240,8 @@ static const struct vb2_ops vimc_cap_qops = {
>   	.wait_finish		= vb2_ops_wait_finish,
>   };
>   
> -/*
> - * NOTE: this function is a copy of v4l2_subdev_link_validate_get_format
> - * maybe the v4l2 function should be public
> - */
> -static int vimc_cap_v4l2_subdev_link_validate_get_format(struct media_pad *pad,
> -						struct v4l2_subdev_format *fmt)
> -{
> -	struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(pad->entity);
> -
> -	fmt->which = V4L2_SUBDEV_FORMAT_ACTIVE;
> -	fmt->pad = pad->index;
> -
> -	return v4l2_subdev_call(sd, pad, get_fmt, NULL, fmt);
> -}
> -
> -static int vimc_cap_link_validate(struct media_link *link)
> -{
> -	struct v4l2_subdev_format source_fmt;
> -	const struct vimc_pix_map *vpix;
> -	struct vimc_cap_device *vcap = container_of(link->sink->entity,
> -						    struct vimc_cap_device,
> -						    vdev.entity);
> -	struct v4l2_pix_format *sink_fmt = &vcap->format;
> -	int ret;
> -
> -	/*
> -	 * if it is a raw node from vimc-core, ignore the link for now
> -	 * TODO: remove this when there are no more raw nodes in the
> -	 * core and return error instead
> -	 */
> -	if (link->source->entity->obj_type == MEDIA_ENTITY_TYPE_BASE)
> -		return 0;
> -
> -	/* Get the the format of the subdev */
> -	ret = vimc_cap_v4l2_subdev_link_validate_get_format(link->source,
> -							    &source_fmt);
> -	if (ret)
> -		return ret;
> -
> -	dev_dbg(vcap->vdev.v4l2_dev->dev,
> -		"%s: link validate formats src:%dx%d %d sink:%dx%d %d\n",
> -		vcap->vdev.name,
> -		source_fmt.format.width, source_fmt.format.height,
> -		source_fmt.format.code,
> -		sink_fmt->width, sink_fmt->height,
> -		sink_fmt->pixelformat);
> -
> -	/* The width, height and code must match. */
> -	vpix = vimc_pix_map_by_pixelformat(sink_fmt->pixelformat);
> -	if (source_fmt.format.width != sink_fmt->width
> -	    || source_fmt.format.height != sink_fmt->height
> -	    || vpix->code != source_fmt.format.code)
> -		return -EPIPE;
> -
> -	/*
> -	 * The field order must match, or the sink field order must be NONE
> -	 * to support interlaced hardware connected to bridges that support
> -	 * progressive formats only.
> -	 */
> -	if (source_fmt.format.field != sink_fmt->field &&
> -	    sink_fmt->field != V4L2_FIELD_NONE)
> -		return -EPIPE;
> -
> -	return 0;
> -}
> -
>   static const struct media_entity_operations vimc_cap_mops = {
> -	.link_validate		= vimc_cap_link_validate,
> +	.link_validate		= vimc_link_validate,
>   };
>   
>   static void vimc_cap_destroy(struct vimc_ent_device *ved)
> @@ -434,6 +377,7 @@ struct vimc_ent_device *vimc_cap_create(struct v4l2_device *v4l2_dev,
>   	vcap->ved.destroy = vimc_cap_destroy;
>   	vcap->ved.ent = &vcap->vdev.entity;
>   	vcap->ved.process_frame = vimc_cap_process_frame;
> +	vcap->ved.vdev_get_format = vimc_cap_get_format;
>   
>   	/* Initialize the video_device struct */
>   	vdev = &vcap->vdev;
> diff --git a/drivers/media/platform/vimc/vimc-common.c b/drivers/media/platform/vimc/vimc-common.c
> index f809a9d..83d4251 100644
> --- a/drivers/media/platform/vimc/vimc-common.c
> +++ b/drivers/media/platform/vimc/vimc-common.c
> @@ -252,8 +252,130 @@ int vimc_pipeline_s_stream(struct media_entity *ent, int enable)
>   	return 0;
>   }
>   
> +static void vimc_fmt_pix_to_mbus(struct v4l2_mbus_framefmt *mfmt,
> +				 struct v4l2_pix_format *pfmt)
> +{
> +	const struct vimc_pix_map *vpix =
> +		vimc_pix_map_by_pixelformat(pfmt->pixelformat);
> +
> +	mfmt->width = pfmt->width;
> +	mfmt->height = pfmt->height;
> +	mfmt->code = vpix->code;
> +	mfmt->field = pfmt->field;
> +	mfmt->colorspace = pfmt->colorspace;
> +	mfmt->ycbcr_enc = pfmt->ycbcr_enc;
> +	mfmt->quantization = pfmt->quantization;
> +	mfmt->xfer_func = pfmt->xfer_func;

You can use v4l2_fill_mbus_format() here.

> +}
> +
> +static int vimc_get_mbus_format(struct media_pad *pad,
> +				struct v4l2_subdev_format *fmt)
> +{
> +	if (is_media_entity_v4l2_subdev(pad->entity)) {
> +		struct v4l2_subdev *sd =
> +			media_entity_to_v4l2_subdev(pad->entity);
> +		int ret;
> +
> +		fmt->which = V4L2_SUBDEV_FORMAT_ACTIVE;
> +		fmt->pad = pad->index;
> +
> +		ret = v4l2_subdev_call(sd, pad, get_fmt, NULL, fmt);
> +		if (ret)
> +			return ret;
> +
> +	} else if (is_media_entity_v4l2_video_device(pad->entity)) {
> +		struct video_device *vdev = container_of(pad->entity,
> +							 struct video_device,
> +							 entity);
> +		struct vimc_ent_device *ved = video_get_drvdata(vdev);
> +		struct v4l2_pix_format vdev_fmt;
> +
> +		if (!ved->vdev_get_format)
> +			return -ENOIOCTLCMD;
> +
> +		ved->vdev_get_format(ved, &vdev_fmt);
> +		vimc_fmt_pix_to_mbus(&fmt->format, &vdev_fmt);
> +	} else {
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +int vimc_link_validate(struct media_link *link)
> +{
> +	struct v4l2_subdev_format source_fmt, sink_fmt;
> +	int ret;
> +
> +	/*
> +	 * if it is a raw node from vimc-core, ignore the link for now
> +	 * TODO: remove this when there are no more raw nodes in the
> +	 * core and return error instead
> +	 */
> +	if (link->source->entity->obj_type == MEDIA_ENTITY_TYPE_BASE)
> +		return 0;
> +
> +	ret = vimc_get_mbus_format(link->source, &source_fmt);
> +	if (ret)
> +		return ret;
> +
> +	ret = vimc_get_mbus_format(link->sink, &sink_fmt);
> +	if (ret)
> +		return ret;
> +
> +	pr_info("vimc link validate: "
> +		"%s:src:%dx%d (0x%x, %d, %d, %d, %d) "
> +		"%s:snk:%dx%d (0x%x, %d, %d, %d, %d)\n",
> +		/* src */
> +		link->source->entity->name,
> +		source_fmt.format.width, source_fmt.format.height,
> +		source_fmt.format.code, source_fmt.format.colorspace,
> +		source_fmt.format.quantization, source_fmt.format.xfer_func,
> +		source_fmt.format.ycbcr_enc,
> +		/* sink */
> +		link->sink->entity->name,
> +		sink_fmt.format.width, sink_fmt.format.height,
> +		sink_fmt.format.code, sink_fmt.format.colorspace,
> +		sink_fmt.format.quantization, sink_fmt.format.xfer_func,
> +		sink_fmt.format.ycbcr_enc);
> +
> +	/* The width, height, code and colorspace must match. */
> +	if (source_fmt.format.width != sink_fmt.format.width
> +	    || source_fmt.format.height != sink_fmt.format.height
> +	    || source_fmt.format.code != sink_fmt.format.code
> +	    || source_fmt.format.colorspace != sink_fmt.format.colorspace)

Source and/or Sink may be COLORSPACE_DEFAULT. If that's the case, then
you should skip comparing ycbcr_enc, quantization or xfer_func. If colorspace
is DEFAULT, then that implies that the other fields are DEFAULT as well. Nothing
else makes sense in that case.

> +		return -EPIPE;
> +
> +	/* Colorimetry must match if they are not set to DEFAULT */
> +	if (source_fmt.format.ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT
> +	    && sink_fmt.format.ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT
> +	    && source_fmt.format.ycbcr_enc != sink_fmt.format.ycbcr_enc)
> +		return -EPIPE;
> +
> +	if (source_fmt.format.quantization != V4L2_QUANTIZATION_DEFAULT
> +	    && sink_fmt.format.quantization != V4L2_QUANTIZATION_DEFAULT
> +	    && source_fmt.format.quantization != sink_fmt.format.quantization)
> +		return -EPIPE;
> +
> +	if (source_fmt.format.xfer_func != V4L2_XFER_FUNC_DEFAULT
> +	    && sink_fmt.format.xfer_func != V4L2_XFER_FUNC_DEFAULT
> +	    && source_fmt.format.xfer_func != sink_fmt.format.xfer_func)
> +		return -EPIPE;
> +
> +	/* The field order must match, or the sink field order must be NONE
> +	 * to support interlaced hardware connected to bridges that support
> +	 * progressive formats only.
> +	 */
> +	if (source_fmt.format.field != sink_fmt.format.field &&
> +	    sink_fmt.format.field != V4L2_FIELD_NONE)
> +		return -EPIPE;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(vimc_link_validate);
> +
>   static const struct media_entity_operations vimc_ent_sd_mops = {
> -	.link_validate = v4l2_subdev_link_validate,
> +	.link_validate = vimc_link_validate,
>   };
>   
>   int vimc_ent_sd_register(struct vimc_ent_device *ved,
> diff --git a/drivers/media/platform/vimc/vimc-common.h b/drivers/media/platform/vimc/vimc-common.h
> index 73e7e94..60ebde2 100644
> --- a/drivers/media/platform/vimc/vimc-common.h
> +++ b/drivers/media/platform/vimc/vimc-common.h
> @@ -45,6 +45,9 @@ struct vimc_pix_map {
>    * @pads:		the list of pads of the node
>    * @destroy:		callback to destroy the node
>    * @process_frame:	callback send a frame to that node
> + * @vdev_get_format:	callback that returns the current format a pad, used
> + *			only when is_media_entity_v4l2_video_device(ent) returns
> + *			true
>    *
>    * Each node of the topology must create a vimc_ent_device struct. Depending on
>    * the node it will be of an instance of v4l2_subdev or video_device struct
> @@ -60,6 +63,8 @@ struct vimc_ent_device {
>   	void (*destroy)(struct vimc_ent_device *);
>   	void (*process_frame)(struct vimc_ent_device *ved,
>   			      struct media_pad *sink, const void *frame);
> +	void (*vdev_get_format)(struct vimc_ent_device *ved,
> +			      struct v4l2_pix_format *fmt);
>   };
>   
>   /**
> @@ -160,4 +165,13 @@ int vimc_ent_sd_register(struct vimc_ent_device *ved,
>   void vimc_ent_sd_unregister(struct vimc_ent_device *ved,
>   			    struct v4l2_subdev *sd);
>   
> +/**
> + * vimc_link_validate - validates a media link
> + *
> + * @link: pointer to &struct media_link
> + *
> + * This function calls validates if a media link is valid for streaming.
> + */
> +int vimc_link_validate(struct media_link *link);
> +
>   #endif
> 

Regards,

	Hans

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