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Date:   Tue, 31 Aug 2021 00:27:42 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Pedro Terra <pedro@terraco.de>
Cc:     hverkuil-cisco@xs4all.nl, dafna.hirschfeld@collabora.com,
        mchehab@kernel.org, skhan@linuxfoundation.org,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        gabrielabittencourt00@gmail.com, gfmandaji@gmail.com
Subject: Re: [PATCH v6] media: vimc: Enable set resolution at the scaler src
 pad
Message-ID: <YS1NToAvQqHSLIm6@pendragon.ideasonboard.com>
References: <20210826174115.28943-1-pedro@terraco.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <20210826174115.28943-1-pedro@terraco.de>
Precedence: bulk

Hi Pedro,

Thank you for the patch.

On Thu, Aug 26, 2021 at 02:41:15PM -0300, Pedro Terra wrote:
> Modify the scaler subdevice to accept setting the resolution of the source
> pad (previously the source resolution would always be 3 times the sink for
> both dimensions). Now any resolution can be set at src (even smaller ones)
> and the sink video will be scaled to match it.
> 
> Test example: With the vimc module up (using the default vimc topology)
> media-ctl -d platform:vimc -V '"Sensor A":0[fmt:SBGGR8_1X8/640x480]'
> media-ctl -d platform:vimc -V '"Debayer A":0[fmt:SBGGR8_1X8/640x480]'
> media-ctl -d platform:vimc -V '"Scaler":0[fmt:RGB888_1X24/640x480]'
> media-ctl -d platform:vimc -V '"Scaler":0[crop:(100,50)/400x150]'
> media-ctl -d platform:vimc -V '"Scaler":1[fmt:RGB888_1X24/300x700]'
> v4l2-ctl -z platform:vimc -d "RGB/YUV Capture" -v width=300,height=700
> v4l2-ctl -z platform:vimc -d "Raw Capture 0" -v pixelformat=BA81
> v4l2-ctl --stream-mmap --stream-count=10 -z platform:vimc -d "RGB/YUV Capture" \
> |-----stream-to=test.raw

This looks weird, I think you meant

	--stream-to=test.raw

> The result will be a cropped stream that can be checked with the command
> ffplay -loglevel warning -v info -f rawvideo -pixel_format rgb24 \
> 	-video_size "300x700" test.raw
> 
> Co-developed-by: Gabriela Bittencourt <gabrielabittencourt00@gmail.com>
> Signed-off-by: Gabriela Bittencourt <gabrielabittencourt00@gmail.com>
> Co-developed-by: Gabriel Francisco Mandaji <gfmandaji@gmail.com>
> Signed-off-by: Gabriel Francisco Mandaji <gfmandaji@gmail.com>
> Signed-off-by: Pedro "pirate" Terra <pirate@terraco.de>
> 
> ---
> 
> Changes in V6:
> * Corrections proposed by Laurent:
> 	- Corrected commit example to become file independent.
> 	- Cleaned unnecessary code inserted at vimc_sca_init_cfg
> 	- s/__u32/u32/
> 	- Refactored vimc_sca_(set/get)_fmt and vimc_sca_(get/set)_selection
> 		as suggested to make it more readable.
> 	- Corrected code alignment.
> 	- Cleaned and optimized vimc_sca_fill_src_frame
> 
> Changes in V5:
> * Fixed code aliment mistake
> * Renamed some variables to make the code more readable
> * Propagate sink pad formatting to src resetting the 1:1 scaling ratio.
> 	(the crop is also reset when this is done).
> 
> Changes in V4:
> * Rebased with media/master
> * Scaling is now compatible with crop
> * Updated test example at the commit message
> * Add vimc prefix to the pad enumeration
> 
> Changes in V3:
> * Corrections suggested by Hans:
> 	- Default scaling factor is now 1 (we removed the define and
> 	  set the source format equals the sink).
> 	- Removed SCA_COUNT (enum that represents the number of pads)
> 	  as there always 2
> 	- Swapped the per byte pixel copy to memcpy.
> * Corrections suggested by Dafna:
> 	- Removed from the documentation the old scaler parameter which
> 	  isn't necessary anymore.
> * Added a thank you note at the end of the email
> 
> Changes in V2:
> * Patch was not sent to media list mail for some reason (even though it
> was on the Cc list), trying again.
> * Updating documentation.
> 
> Running
> /usr/local/bin/v4l2-compliance -m /dev/media0
> Gave the following result:
> v4l2-compliance SHA: c86aab9cc7f1 2021-07-28 11:52:45
> Grand Total for vimc device /dev/media0: 473, Succeeded: 473, Failed: 0, Warnings: 0
> ---
>  Documentation/admin-guide/media/vimc.rst      |  22 +-
>  drivers/media/test-drivers/vimc/vimc-scaler.c | 368 +++++++-----------
>  2 files changed, 150 insertions(+), 240 deletions(-)
> 
> diff --git a/Documentation/admin-guide/media/vimc.rst b/Documentation/admin-guide/media/vimc.rst
> index 211cc8972410..34de709e9f8e 100644
> --- a/Documentation/admin-guide/media/vimc.rst
> +++ b/Documentation/admin-guide/media/vimc.rst
> @@ -61,10 +61,11 @@ vimc-debayer:
>  	* 1 Pad source
>  
>  vimc-scaler:
> -	Scale up the image by a factor of 3. E.g.: a 640x480 image becomes a
> -        1920x1440 image. (this value can be configured, see at
> -        `Module options`_).
> -	Exposes:
> +	Re-size the image to meet the source pad resolution. E.g.: if the sync pad
> +is configured to 360x480 and the source to 1280x720, the image will be stretched
> +to fit the source resolution. Works for any resolution within the vimc
> +limitations (even shrinking the image if necessary).
> +Exposes:

Indentation is important, this will cause a documentation build warning:

Documentation/admin-guide/media/vimc.rst:65: WARNING: Definition list ends without a blank line; unexpected unindent.

It should be written

	Re-size the image to meet the source pad resolution. E.g.: if the sync
	pad is configured to 360x480 and the source to 1280x720, the image will
	be stretched to fit the source resolution. Works for any resolution
	within the vimc limitations (even shrinking the image if necessary).
	Exposes:

>  
>  	* 1 Pad sink
>  	* 1 Pad source
> @@ -75,16 +76,3 @@ vimc-capture:
>  
>  	* 1 Pad sink
>  	* 1 Pad source
> -
> -
> -Module options
> ---------------
> -
> -Vimc has a module parameter to configure the driver.
> -
> -* ``sca_mult=<unsigned int>``
> -
> -        Image size multiplier factor to be used to multiply both width and
> -        height, so the image size will be ``sca_mult^2`` bigger than the
> -        original one. Currently, only supports scaling up (the default value
> -        is 3).
> diff --git a/drivers/media/test-drivers/vimc/vimc-scaler.c b/drivers/media/test-drivers/vimc/vimc-scaler.c
> index 06880dd0b6ac..13adad8d03c5 100644
> --- a/drivers/media/test-drivers/vimc/vimc-scaler.c
> +++ b/drivers/media/test-drivers/vimc/vimc-scaler.c
> @@ -6,6 +6,7 @@
>   */
>  
>  #include <linux/moduleparam.h>
> +#include <linux/string.h>
>  #include <linux/vmalloc.h>
>  #include <linux/v4l2-mediabus.h>
>  #include <media/v4l2-rect.h>
> @@ -13,11 +14,11 @@
>  
>  #include "vimc-common.h"
>  
> -static unsigned int sca_mult = 3;
> -module_param(sca_mult, uint, 0000);
> -MODULE_PARM_DESC(sca_mult, " the image size multiplier");
> -
> -#define MAX_ZOOM	8
> +/* Pad identifier */
> +enum vic_sca_pad {
> +	VIMC_SCA_SINK = 0,
> +	VIMC_SCA_SRC = 1,
> +};
>  
>  #define VIMC_SCA_FMT_WIDTH_DEFAULT  640
>  #define VIMC_SCA_FMT_HEIGHT_DEFAULT 480
> @@ -25,19 +26,16 @@ MODULE_PARM_DESC(sca_mult, " the image size multiplier");
>  struct vimc_sca_device {
>  	struct vimc_ent_device ved;
>  	struct v4l2_subdev sd;
> -	/* NOTE: the source fmt is the same as the sink
> -	 * with the width and hight multiplied by mult
> -	 */
> -	struct v4l2_mbus_framefmt sink_fmt;
>  	struct v4l2_rect crop_rect;
> +	/* Frame format for both sink and src pad */
> +	struct v4l2_mbus_framefmt fmt[2];
>  	/* Values calculated when the stream starts */
>  	u8 *src_frame;
> -	unsigned int src_line_size;
>  	unsigned int bpp;
>  	struct media_pad pads[2];
>  };
>  
> -static const struct v4l2_mbus_framefmt sink_fmt_default = {
> +static const struct v4l2_mbus_framefmt fmt_default = {
>  	.width = VIMC_SCA_FMT_WIDTH_DEFAULT,
>  	.height = VIMC_SCA_FMT_HEIGHT_DEFAULT,
>  	.code = MEDIA_BUS_FMT_RGB888_1X24,
> @@ -72,17 +70,6 @@ vimc_sca_get_crop_bound_sink(const struct v4l2_mbus_framefmt *sink_fmt)
>  	return r;
>  }
>  
> -static void vimc_sca_adjust_sink_crop(struct v4l2_rect *r,
> -				      const struct v4l2_mbus_framefmt *sink_fmt)
> -{
> -	const struct v4l2_rect sink_rect =
> -		vimc_sca_get_crop_bound_sink(sink_fmt);
> -
> -	/* Disallow rectangles smaller than the minimal one. */
> -	v4l2_rect_set_min_size(r, &crop_rect_min);
> -	v4l2_rect_map_inside(r, &sink_rect);
> -}
> -
>  static int vimc_sca_init_cfg(struct v4l2_subdev *sd,
>  			     struct v4l2_subdev_state *sd_state)
>  {
> @@ -90,19 +77,14 @@ static int vimc_sca_init_cfg(struct v4l2_subdev *sd,
>  	struct v4l2_rect *r;
>  	unsigned int i;
>  
> -	mf = v4l2_subdev_get_try_format(sd, sd_state, 0);
> -	*mf = sink_fmt_default;
> -
> -	r = v4l2_subdev_get_try_crop(sd, sd_state, 0);
> -	*r = crop_rect_default;
> -
>  	for (i = 1; i < sd->entity.num_pads; i++) {

Shouldn't the loop start at index 0 ?

>  		mf = v4l2_subdev_get_try_format(sd, sd_state, i);
> -		*mf = sink_fmt_default;
> -		mf->width = mf->width * sca_mult;
> -		mf->height = mf->height * sca_mult;
> +		*mf = fmt_default;
>  	}
>  
> +	r = v4l2_subdev_get_try_crop(sd, sd_state, VIMC_SCA_SINK);
> +	*r = crop_rect_default;
> +
>  	return 0;
>  }
>  
> @@ -144,112 +126,108 @@ static int vimc_sca_enum_frame_size(struct v4l2_subdev *sd,
>  	fse->min_width = VIMC_FRAME_MIN_WIDTH;
>  	fse->min_height = VIMC_FRAME_MIN_HEIGHT;
>  
> -	if (VIMC_IS_SINK(fse->pad)) {
> -		fse->max_width = VIMC_FRAME_MAX_WIDTH;
> -		fse->max_height = VIMC_FRAME_MAX_HEIGHT;
> -	} else {
> -		fse->max_width = VIMC_FRAME_MAX_WIDTH * MAX_ZOOM;
> -		fse->max_height = VIMC_FRAME_MAX_HEIGHT * MAX_ZOOM;
> -	}
> +	fse->max_width = VIMC_FRAME_MAX_WIDTH;
> +	fse->max_height = VIMC_FRAME_MAX_HEIGHT;
>  
>  	return 0;
>  }
>  
> -static int vimc_sca_get_fmt(struct v4l2_subdev *sd,
> +static struct v4l2_mbus_framefmt *
> +vimc_sca_pad_format(struct vimc_sca_device *vsca,
> +		    struct v4l2_subdev_state *sd_state, u32 pad,
> +		    enum v4l2_subdev_format_whence which)
> +{
> +	if (which == V4L2_SUBDEV_FORMAT_TRY)
> +		return v4l2_subdev_get_try_format(&vsca->sd, sd_state, pad);
> +	else
> +		return &vsca->fmt[pad];
> +}
> +
> +static struct v4l2_rect *
> +vimc_sca_pad_crop(struct vimc_sca_device *vsca,
> +		  struct v4l2_subdev_state *sd_state,
> +		  enum v4l2_subdev_format_whence which)
> +{
> +	if (which == V4L2_SUBDEV_FORMAT_TRY)
> +		return v4l2_subdev_get_try_crop(&vsca->sd, sd_state,
> +						VIMC_SCA_SINK);
> +	else
> +		return &vsca->crop_rect;
> +}
> +
> +static int vimc_sca_set_fmt(struct v4l2_subdev *sd,
>  			    struct v4l2_subdev_state *sd_state,
>  			    struct v4l2_subdev_format *format)
>  {
>  	struct vimc_sca_device *vsca = v4l2_get_subdevdata(sd);
> -	struct v4l2_rect *crop_rect;
> +	struct v4l2_mbus_framefmt *fmt;
>  
> -	/* Get the current sink format */
> -	if (format->which == V4L2_SUBDEV_FORMAT_TRY) {
> -		format->format = *v4l2_subdev_get_try_format(sd, sd_state, 0);
> -		crop_rect = v4l2_subdev_get_try_crop(sd, sd_state, 0);
> -	} else {
> -		format->format = vsca->sink_fmt;
> -		crop_rect = &vsca->crop_rect;
> -	}
> +	/* Do not change the active format while stream is on */
> +	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE && vsca->src_frame)
> +		return -EBUSY;
>  
> -	/* Scale the frame size for the source pad */
> -	if (VIMC_IS_SRC(format->pad)) {
> -		format->format.width = crop_rect->width * sca_mult;
> -		format->format.height = crop_rect->height * sca_mult;
> -	}
> +	fmt = vimc_sca_pad_format(vsca, sd_state, format->pad, format->which);
>  
> -	return 0;
> -}
> -
> -static void vimc_sca_adjust_sink_fmt(struct v4l2_mbus_framefmt *fmt)
> -{
> -	const struct vimc_pix_map *vpix;
> +	/*
> +	 * The media bus code and colorspace can only be changed on the sink
> +	 * pad, the source pad only follows.
> +	 */
> +	if (format->pad == VIMC_SCA_SINK) {
> +		const struct vimc_pix_map *vpix;
>  
> -	/* Only accept code in the pix map table in non bayer format */
> -	vpix = vimc_pix_map_by_code(fmt->code);
> -	if (!vpix || vpix->bayer)
> -		fmt->code = sink_fmt_default.code;
> +		/* Only accept code in the pix map table in non bayer format. */
> +		vpix = vimc_pix_map_by_code(format->format.code);
> +		if (vpix && !vpix->bayer)
> +			fmt->code = format->format.code;
> +		else
> +			fmt->code = fmt_default.code;
> +
> +		/* Clamp the colorspace to valid values. */
> +		fmt->colorspace = format->format.colorspace;
> +		fmt->ycbcr_enc = format->format.ycbcr_enc;
> +		fmt->quantization = format->format.quantization;
> +		fmt->xfer_func = format->format.xfer_func;
> +		vimc_colorimetry_clamp(fmt);
> +	}
>  
> -	fmt->width = clamp_t(u32, fmt->width, VIMC_FRAME_MIN_WIDTH,
> +	/* Clamp and align the width and height */
> +	fmt->width = clamp_t(u32, format->format.width, VIMC_FRAME_MIN_WIDTH,
>  			     VIMC_FRAME_MAX_WIDTH) & ~1;
> -	fmt->height = clamp_t(u32, fmt->height, VIMC_FRAME_MIN_HEIGHT,
> +	fmt->height = clamp_t(u32, format->format.height, VIMC_FRAME_MIN_HEIGHT,
>  			      VIMC_FRAME_MAX_HEIGHT) & ~1;
>  
> -	if (fmt->field == V4L2_FIELD_ANY)
> -		fmt->field = sink_fmt_default.field;
> +	/*
> +	 * Propagate the sink pad format to the crop rectangle and the source
> +	 * pad.
> +	 */
> +	if (format->pad == VIMC_SCA_SINK) {
> +		struct v4l2_mbus_framefmt *src_fmt;
> +		struct v4l2_rect *crop;
> +
> +		crop = vimc_sca_pad_crop(vsca, sd_state, format->which);
> +		crop->width = fmt->width;
> +		crop->height = fmt->height;
> +		crop->top = 0;
> +		crop->left = 0;
> +
> +		src_fmt = vimc_sca_pad_format(vsca, sd_state, VIMC_SCA_SRC,
> +					      format->which);
> +		*src_fmt = *fmt;
> +	}
>  
> -	vimc_colorimetry_clamp(fmt);
> +	format->format = *fmt;
> +
> +	return 0;
>  }
>  
> -static int vimc_sca_set_fmt(struct v4l2_subdev *sd,
> +static int vimc_sca_get_fmt(struct v4l2_subdev *sd,
>  			    struct v4l2_subdev_state *sd_state,
> -			    struct v4l2_subdev_format *fmt)
> +			    struct v4l2_subdev_format *format)
>  {
>  	struct vimc_sca_device *vsca = v4l2_get_subdevdata(sd);
> -	struct v4l2_mbus_framefmt *sink_fmt;
> -	struct v4l2_rect *crop_rect;
> -
> -	if (fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> -		/* Do not change the format while stream is on */
> -		if (vsca->src_frame)
> -			return -EBUSY;
> -
> -		sink_fmt = &vsca->sink_fmt;
> -		crop_rect = &vsca->crop_rect;
> -	} else {
> -		sink_fmt = v4l2_subdev_get_try_format(sd, sd_state, 0);
> -		crop_rect = v4l2_subdev_get_try_crop(sd, sd_state, 0);
> -	}
> -
> -	/*
> -	 * Do not change the format of the source pad,
> -	 * it is propagated from the sink
> -	 */
> -	if (VIMC_IS_SRC(fmt->pad)) {
> -		fmt->format = *sink_fmt;
> -		fmt->format.width = crop_rect->width * sca_mult;
> -		fmt->format.height = crop_rect->height * sca_mult;
> -	} else {
> -		/* Set the new format in the sink pad */
> -		vimc_sca_adjust_sink_fmt(&fmt->format);
> -
> -		dev_dbg(vsca->ved.dev, "%s: sink format update: "
> -			"old:%dx%d (0x%x, %d, %d, %d, %d) "
> -			"new:%dx%d (0x%x, %d, %d, %d, %d)\n", vsca->sd.name,
> -			/* old */
> -			sink_fmt->width, sink_fmt->height, sink_fmt->code,
> -			sink_fmt->colorspace, sink_fmt->quantization,
> -			sink_fmt->xfer_func, sink_fmt->ycbcr_enc,
> -			/* new */
> -			fmt->format.width, fmt->format.height, fmt->format.code,
> -			fmt->format.colorspace,	fmt->format.quantization,
> -			fmt->format.xfer_func, fmt->format.ycbcr_enc);
> -
> -		*sink_fmt = fmt->format;
> -
> -		/* Do the crop, but respect the current bounds */
> -		vimc_sca_adjust_sink_crop(crop_rect, sink_fmt);
> -	}
>  
> +	format->format = *vimc_sca_pad_format(vsca, sd_state, format->pad,
> +					      format->which);
>  	return 0;
>  }

I'd place vimc_sca_get_fmt() before vimc_sca_set_fmt() as that's the
order in which they're set in the v4l2_subdev_pad_ops structure (and it
would also match the existing order), but that's a small issue.

>  
> @@ -259,24 +237,17 @@ static int vimc_sca_get_selection(struct v4l2_subdev *sd,
>  {
>  	struct vimc_sca_device *vsca = v4l2_get_subdevdata(sd);
>  	struct v4l2_mbus_framefmt *sink_fmt;
> -	struct v4l2_rect *crop_rect;
>  
>  	if (VIMC_IS_SRC(sel->pad))
>  		return -EINVAL;
>  
> -	if (sel->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> -		sink_fmt = &vsca->sink_fmt;
> -		crop_rect = &vsca->crop_rect;
> -	} else {
> -		sink_fmt = v4l2_subdev_get_try_format(sd, sd_state, 0);
> -		crop_rect = v4l2_subdev_get_try_crop(sd, sd_state, 0);
> -	}
> -
>  	switch (sel->target) {
>  	case V4L2_SEL_TGT_CROP:
> -		sel->r = *crop_rect;
> +		sel->r = *vimc_sca_pad_crop(vsca, sd_state, sel->which);
>  		break;
>  	case V4L2_SEL_TGT_CROP_BOUNDS:
> +		sink_fmt = vimc_sca_pad_format(vsca, sd_state, VIMC_SCA_SINK,
> +					       sel->which);
>  		sel->r = vimc_sca_get_crop_bound_sink(sink_fmt);
>  		break;
>  	default:
> @@ -286,6 +257,17 @@ static int vimc_sca_get_selection(struct v4l2_subdev *sd,
>  	return 0;
>  }
>  
> +static void vimc_sca_adjust_sink_crop(struct v4l2_rect *r,
> +				      const struct v4l2_mbus_framefmt *sink_fmt)
> +{
> +	const struct v4l2_rect sink_rect =
> +		vimc_sca_get_crop_bound_sink(sink_fmt);
> +
> +	/* Disallow rectangles smaller than the minimal one. */
> +	v4l2_rect_set_min_size(r, &crop_rect_min);
> +	v4l2_rect_map_inside(r, &sink_rect);
> +}
> +
>  static int vimc_sca_set_selection(struct v4l2_subdev *sd,
>  				  struct v4l2_subdev_state *sd_state,
>  				  struct v4l2_subdev_selection *sel)
> @@ -294,30 +276,18 @@ static int vimc_sca_set_selection(struct v4l2_subdev *sd,
>  	struct v4l2_mbus_framefmt *sink_fmt;
>  	struct v4l2_rect *crop_rect;
>  
> -	if (VIMC_IS_SRC(sel->pad))
> +	/* Only support setting the crop of the sink pad */
> +	if (VIMC_IS_SRC(sel->pad) || sel->target != V4L2_SEL_TGT_CROP)
>  		return -EINVAL;
>  
> -	if (sel->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> -		/* Do not change the format while stream is on */
> -		if (vsca->src_frame)
> -			return -EBUSY;
> +	if (sel->which == V4L2_SUBDEV_FORMAT_ACTIVE && vsca->src_frame)
> +		return -EBUSY;
>  
> -		crop_rect = &vsca->crop_rect;
> -		sink_fmt = &vsca->sink_fmt;
> -	} else {
> -		crop_rect = v4l2_subdev_get_try_crop(sd, sd_state, 0);
> -		sink_fmt = v4l2_subdev_get_try_format(sd, sd_state, 0);
> -	}
> -
> -	switch (sel->target) {
> -	case V4L2_SEL_TGT_CROP:
> -		/* Do the crop, but respect the current bounds */
> -		vimc_sca_adjust_sink_crop(&sel->r, sink_fmt);
> -		*crop_rect = sel->r;
> -		break;
> -	default:
> -		return -EINVAL;
> -	}
> +	crop_rect = vimc_sca_pad_crop(vsca, sd_state, sel->which);
> +	sink_fmt = vimc_sca_pad_format(vsca, sd_state, VIMC_SCA_SINK,
> +				       sel->which);
> +	vimc_sca_adjust_sink_crop(&sel->r, sink_fmt);
> +	*crop_rect = sel->r;
>  
>  	return 0;
>  }
> @@ -344,16 +314,12 @@ static int vimc_sca_s_stream(struct v4l2_subdev *sd, int enable)
>  			return 0;
>  
>  		/* Save the bytes per pixel of the sink */
> -		vpix = vimc_pix_map_by_code(vsca->sink_fmt.code);
> +		vpix = vimc_pix_map_by_code(vsca->fmt[VIMC_SCA_SINK].code);
>  		vsca->bpp = vpix->bpp;
>  
> -		/* Calculate the width in bytes of the src frame */
> -		vsca->src_line_size = vsca->crop_rect.width *
> -				      sca_mult * vsca->bpp;
> -
>  		/* Calculate the frame size of the source pad */
> -		frame_size = vsca->src_line_size * vsca->crop_rect.height *
> -			     sca_mult;
> +		frame_size = vsca->fmt[VIMC_SCA_SRC].width
> +			   * vsca->fmt[VIMC_SCA_SRC].height * vsca->bpp;
>  
>  		/* Allocate the frame buffer. Use vmalloc to be able to
>  		 * allocate a large amount of memory
> @@ -382,77 +348,32 @@ static const struct v4l2_subdev_ops vimc_sca_ops = {
>  	.video = &vimc_sca_video_ops,
>  };
>  
> -static void vimc_sca_fill_pix(u8 *const ptr,
> -			      const u8 *const pixel,
> -			      const unsigned int bpp)
> -{
> -	unsigned int i;
> -
> -	/* copy the pixel to the pointer */
> -	for (i = 0; i < bpp; i++)
> -		ptr[i] = pixel[i];
> -}
> -
> -static void vimc_sca_scale_pix(const struct vimc_sca_device *const vsca,
> -			       unsigned int lin, unsigned int col,
> -			       const u8 *const sink_frame)
> -{
> -	const struct v4l2_rect crop_rect = vsca->crop_rect;
> -	unsigned int i, j, index;
> -	const u8 *pixel;
> -
> -	/* Point to the pixel value in position (lin, col) in the sink frame */
> -	index = VIMC_FRAME_INDEX(lin, col,
> -				 vsca->sink_fmt.width,
> -				 vsca->bpp);
> -	pixel = &sink_frame[index];
> -
> -	dev_dbg(vsca->ved.dev,
> -		"sca: %s: --- scale_pix sink pos %dx%d, index %d ---\n",
> -		vsca->sd.name, lin, col, index);
> -
> -	/* point to the place we are going to put the first pixel
> -	 * in the scaled src frame
> -	 */
> -	lin -= crop_rect.top;
> -	col -= crop_rect.left;
> -	index = VIMC_FRAME_INDEX(lin * sca_mult, col * sca_mult,
> -				 crop_rect.width * sca_mult, vsca->bpp);
> -
> -	dev_dbg(vsca->ved.dev, "sca: %s: scale_pix src pos %dx%d, index %d\n",
> -		vsca->sd.name, lin * sca_mult, col * sca_mult, index);
> -
> -	/* Repeat this pixel mult times */
> -	for (i = 0; i < sca_mult; i++) {
> -		/* Iterate through each beginning of a
> -		 * pixel repetition in a line
> -		 */
> -		for (j = 0; j < sca_mult * vsca->bpp; j += vsca->bpp) {
> -			dev_dbg(vsca->ved.dev,
> -				"sca: %s: sca: scale_pix src pos %d\n",
> -				vsca->sd.name, index + j);
> -
> -			/* copy the pixel to the position index + j */
> -			vimc_sca_fill_pix(&vsca->src_frame[index + j],
> -					  pixel, vsca->bpp);
> -		}
> -
> -		/* move the index to the next line */
> -		index += vsca->src_line_size;
> -	}
> -}
> -
>  static void vimc_sca_fill_src_frame(const struct vimc_sca_device *const vsca,
>  				    const u8 *const sink_frame)
>  {
> -	const struct v4l2_rect r = vsca->crop_rect;
> -	unsigned int i, j;
> -
> -	/* Scale each pixel from the original sink frame */
> -	/* TODO: implement scale down, only scale up is supported for now */
> -	for (i = r.top; i < r.top + r.height; i++)
> -		for (j = r.left; j < r.left + r.width; j++)
> -			vimc_sca_scale_pix(vsca, i, j, sink_frame);
> +	const struct v4l2_mbus_framefmt *src_fmt = &vsca->fmt[VIMC_SCA_SRC];
> +	const struct v4l2_rect *r = &vsca->crop_rect;
> +	unsigned int snk_width = vsca->fmt[VIMC_SCA_SINK].width;
> +	unsigned int src_x, src_y;
> +	u8 *walker = vsca->src_frame;
> +
> +	/* Set each pixel at the src_frame to its sink_frame equivalent */
> +	for (src_y = 0; src_y < src_fmt->height; src_y++) {
> +		unsigned int snk_y, col_offset;
> +
> +		snk_y = (src_y * r->height) / src_fmt->height + r->top;
> +		col_offset = snk_y * snk_width * vsca->bpp;

Isn't this the line offset ? Or do you mean column offset as vertical
offset within a column ? Maybe naming the variable y_offset (and
x_offset) below could lift the ambiguity.

Those are minor issues, I think v7 could well be the last one :-)

> +
> +		for (src_x = 0; src_x < src_fmt->width; src_x++) {
> +			unsigned int snk_x, lin_offset, index;
> +
> +			snk_x = (src_x * r->width) / src_fmt->width + r->left;
> +			lin_offset = snk_x * vsca->bpp;
> +			index = col_offset + lin_offset;
> +			memcpy(walker, &sink_frame[index], vsca->bpp);
> +			walker += vsca->bpp;
> +		}
> +	}
>  }
>  
>  static void *vimc_sca_process_frame(struct vimc_ent_device *ved,
> @@ -492,8 +413,8 @@ static struct vimc_ent_device *vimc_sca_add(struct vimc_device *vimc,
>  		return ERR_PTR(-ENOMEM);
>  
>  	/* Initialize ved and sd */
> -	vsca->pads[0].flags = MEDIA_PAD_FL_SINK;
> -	vsca->pads[1].flags = MEDIA_PAD_FL_SOURCE;
> +	vsca->pads[VIMC_SCA_SINK].flags = MEDIA_PAD_FL_SINK;
> +	vsca->pads[VIMC_SCA_SRC].flags = MEDIA_PAD_FL_SOURCE;
>  
>  	ret = vimc_ent_sd_register(&vsca->ved, &vsca->sd, v4l2_dev,
>  				   vcfg_name,
> @@ -508,7 +429,8 @@ static struct vimc_ent_device *vimc_sca_add(struct vimc_device *vimc,
>  	vsca->ved.dev = vimc->mdev.dev;
>  
>  	/* Initialize the frame format */
> -	vsca->sink_fmt = sink_fmt_default;
> +	vsca->fmt[VIMC_SCA_SINK] = fmt_default;
> +	vsca->fmt[VIMC_SCA_SRC] = fmt_default;
>  
>  	/* Initialize the crop selection */
>  	vsca->crop_rect = crop_rect_default;

-- 
Regards,

Laurent Pinchart