Re: [PATCH 10/15] v4l: vsp1: Move DRM pipeline output setup code to a function

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

Hi Kieran,

On Thursday, 29 March 2018 14:49:12 EEST Kieran Bingham wrote:
> Hi Laurent,
> 
> Thank you for another patch :D

You're welcome, there will be more ;-)

> On 26/02/18 21:45, Laurent Pinchart wrote:
> > In order to make the vsp1_du_setup_lif() easier to read, and for
> > symmetry with the DRM pipeline input setup, move the pipeline output
> > setup code to a separate function.
> > 
> > Signed-off-by: Laurent Pinchart
> > <laurent.pinchart+renesas@ideasonboard.com>
> 
> Just an easy code move. And I agree it improves things.
> 
> Small question below, but otherwise:
> 
> Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> 
> > ---
> > 
> >  drivers/media/platform/vsp1/vsp1_drm.c | 107 ++++++++++++++++------------
> >  1 file changed, 61 insertions(+), 46 deletions(-)
> > 
> > diff --git a/drivers/media/platform/vsp1/vsp1_drm.c
> > b/drivers/media/platform/vsp1/vsp1_drm.c index 00ce99bd1605..1c8adda47440
> > 100644
> > --- a/drivers/media/platform/vsp1/vsp1_drm.c
> > +++ b/drivers/media/platform/vsp1/vsp1_drm.c
> > @@ -276,6 +276,66 @@ static int vsp1_du_pipeline_setup_input(struct
> > vsp1_device *vsp1,
> >  	return 0;
> >  
> >  }
> > 
> > +/* Setup the output side of the pipeline (WPF and LIF). */
> > +static int vsp1_du_pipeline_setup_output(struct vsp1_device *vsp1,
> > +					 struct vsp1_pipeline *pipe)
> > +{
> > +	struct vsp1_drm_pipeline *drm_pipe = to_vsp1_drm_pipeline(pipe);
> > +	struct v4l2_subdev_format format = {
> > +		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
> 
> Why do you initialise this .which here, but all the other member variables
> below.
> 
> Wouldn't it make more sense to group all of this initialisation together? or
> is there a distinction in keeping the .which separate.
> 
> (Perhaps this is just a way to initialise the rest of the structure to 0,
> without using the memset?)

The initialization of the .which field is indeed there to avoid the memset, 
but other than that there's no particular reason. I find it clearer to keep 
the initialization of the structure close to the code that makes use of it 
(the next v4l2_subdev_call in this case).

As initializing all members when declaring the variable doesn't make a change 
in code size (gcc 6.4.0) but increases .rodata by 18 bytes and decreases 
__modver by the same amount, I'm tempted to leave it as-is unless you think it 
should be changed.

> > +	};
> > +	int ret;
> > +
> > +	format.pad = RWPF_PAD_SINK;
> > +	format.format.width = drm_pipe->width;
> > +	format.format.height = drm_pipe->height;
> > +	format.format.code = MEDIA_BUS_FMT_ARGB8888_1X32;
> > +	format.format.field = V4L2_FIELD_NONE;
> > +
> > +	ret = v4l2_subdev_call(&pipe->output->entity.subdev, pad, set_fmt, 
NULL,
> > +			       &format);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	dev_dbg(vsp1->dev, "%s: set format %ux%u (%x) on WPF%u sink\n",
> > +		__func__, format.format.width, format.format.height,
> > +		format.format.code, pipe->output->entity.index);
> > +
> > +	format.pad = RWPF_PAD_SOURCE;
> > +	ret = v4l2_subdev_call(&pipe->output->entity.subdev, pad, get_fmt, 
NULL,
> > +			       &format);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	dev_dbg(vsp1->dev, "%s: got format %ux%u (%x) on WPF%u source\n",
> > +		__func__, format.format.width, format.format.height,
> > +		format.format.code, pipe->output->entity.index);
> > +
> > +	format.pad = LIF_PAD_SINK;
> > +	ret = v4l2_subdev_call(&pipe->lif->subdev, pad, set_fmt, NULL,
> > +			       &format);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	dev_dbg(vsp1->dev, "%s: set format %ux%u (%x) on LIF%u sink\n",
> > +		__func__, format.format.width, format.format.height,
> > +		format.format.code, pipe->lif->index);
> > +
> > +	/*
> > +	 * Verify that the format at the output of the pipeline matches the
> > +	 * requested frame size and media bus code.
> > +	 */
> > +	if (format.format.width != drm_pipe->width ||
> > +	    format.format.height != drm_pipe->height ||
> > +	    format.format.code != MEDIA_BUS_FMT_ARGB8888_1X32) {
> > +		dev_dbg(vsp1->dev, "%s: format mismatch on LIF%u\n", __func__,
> > +			pipe->lif->index);
> > +		return -EPIPE;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > 
> >  /* Configure all entities in the pipeline. */
> >  static void vsp1_du_pipeline_configure(struct vsp1_pipeline *pipe)
> >  {
> > 
> > @@ -356,7 +416,6 @@ int vsp1_du_setup_lif(struct device *dev, unsigned int
> > pipe_index,> 
> >  	struct vsp1_drm_pipeline *drm_pipe;
> >  	struct vsp1_pipeline *pipe;
> >  	struct vsp1_bru *bru;
> > 
> > -	struct v4l2_subdev_format format;
> > 
> >  	unsigned long flags;
> >  	unsigned int i;
> >  	int ret;
> > 
> > @@ -417,54 +476,10 @@ int vsp1_du_setup_lif(struct device *dev, unsigned
> > int pipe_index,> 
> >  	if (ret < 0)
> >  	
> >  		return ret;
> > 
> > -	memset(&format, 0, sizeof(format));
> > -	format.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> > -	format.pad = RWPF_PAD_SINK;
> > -	format.format.width = cfg->width;
> > -	format.format.height = cfg->height;
> > -	format.format.code = MEDIA_BUS_FMT_ARGB8888_1X32;
> > -	format.format.field = V4L2_FIELD_NONE;
> > -
> > -	ret = v4l2_subdev_call(&pipe->output->entity.subdev, pad, set_fmt, 
NULL,
> > -			       &format);
> > +	ret = vsp1_du_pipeline_setup_output(vsp1, pipe);
> > 
> >  	if (ret < 0)
> >  	
> >  		return ret;
> > 
> > -	dev_dbg(vsp1->dev, "%s: set format %ux%u (%x) on WPF%u sink\n",
> > -		__func__, format.format.width, format.format.height,
> > -		format.format.code, pipe->output->entity.index);
> > -
> > -	format.pad = RWPF_PAD_SOURCE;
> > -	ret = v4l2_subdev_call(&pipe->output->entity.subdev, pad, get_fmt, 
NULL,
> > -			       &format);
> > -	if (ret < 0)
> > -		return ret;
> > -
> > -	dev_dbg(vsp1->dev, "%s: got format %ux%u (%x) on WPF%u source\n",
> > -		__func__, format.format.width, format.format.height,
> > -		format.format.code, pipe->output->entity.index);
> > -
> > -	format.pad = LIF_PAD_SINK;
> > -	ret = v4l2_subdev_call(&pipe->lif->subdev, pad, set_fmt, NULL,
> > -			       &format);
> > -	if (ret < 0)
> > -		return ret;
> > -
> > -	dev_dbg(vsp1->dev, "%s: set format %ux%u (%x) on LIF%u sink\n",
> > -		__func__, format.format.width, format.format.height,
> > -		format.format.code, pipe_index);
> > -
> > -	/*
> > -	 * Verify that the format at the output of the pipeline matches the
> > -	 * requested frame size and media bus code.
> > -	 */
> > -	if (format.format.width != cfg->width ||
> > -	    format.format.height != cfg->height ||
> > -	    format.format.code != MEDIA_BUS_FMT_ARGB8888_1X32) {
> > -		dev_dbg(vsp1->dev, "%s: format mismatch\n", __func__);
> > -		return -EPIPE;
> > -	}
> > -
> > 
> >  	/* Enable the VSP1. */
> >  	ret = vsp1_device_get(vsp1);
> >  	if (ret < 0)

-- 
Regards,

Laurent Pinchart