Re: [PATCH v2] media: vimc: Enable set resolution at the scaler src pad

From: Hans Verkuil
Date: Fri Sep 20 2019 - 07:00:06 EST


Hi Pedro, Gabriela, Gabriel,

On 9/15/19 11:35 PM, 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 /dev/media0 -V '"Sensor A":0[fmt:SBGGR8_1X8/640x480]'
> media-ctl -d /dev/media0 -V '"Debayer A":0[fmt:SBGGR8_1X8/640x480]'
> media-ctl -d /dev/media0 -V '"Scaler":0[fmt:SBGGR8_1X8/640x480]'
> media-ctl -d /dev/media0 -V '"Scaler":1[fmt:SBGGR8_1X8/300x700]'
> v4l2-ctl -d /dev/video2 -v width=300,height=700
> v4l2-ctl -d /dev/video0 -v pixelformat=BA81
> v4l2-ctl --stream-mmap --stream-count=10 -d /dev/video2 \
> --stream-to=test.raw
> ffplay -loglevel warning -v info -f rawvideo -pixel_format rgb24 \
> -video_size "300x700" test.raw
>
> Co-developed-by: Gabriela Bittencourt <gabrielabittencourt00@xxxxxxxxx>
> Signed-off-by: Gabriela Bittencourt <gabrielabittencourt00@xxxxxxxxx>
> Co-developed-by: Gabriel Francisco Mandaji <gfmandaji@xxxxxxxxx>
> Signed-off-by: Gabriel Francisco Mandaji <gfmandaji@xxxxxxxxx>
> Signed-off-by: Pedro "pirate" Terra <pirate@xxxxxxxxxx>
>
> ---
>
> 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.
>
> Hello! This patch depends on the series:
> "Collapse vimc into single monolithic driver" V3
> This code is the result of friends getting together with too much
> coffee, sugar and beer trying to get started with some kernel coding.
> Please, don't go easy on us! s2

Well, since you asked... :-)

>
> Running
> /usr/local/bin/v4l2-compliance -m /dev/media0
> Gave the following result:
> v4l2-compliance SHA: b393a5408383b7341883857dfda78537f2f85ef6, 64 bits
> Grand Total for vimc device /dev/media0: 451, Succeeded: 451, Failed: 0, Warnings: 0
> ---
> Documentation/media/v4l-drivers/vimc.rst | 15 +-
> drivers/media/platform/vimc/vimc-scaler.c | 217 +++++++---------------
> 2 files changed, 77 insertions(+), 155 deletions(-)
>
> diff --git a/Documentation/media/v4l-drivers/vimc.rst b/Documentation/media/v4l-drivers/vimc.rst
> index a582af0509ee..c28c635d965c 100644
> --- a/Documentation/media/v4l-drivers/vimc.rst
> +++ b/Documentation/media/v4l-drivers/vimc.rst
> @@ -61,9 +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`_).
> + 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
> @@ -84,13 +86,6 @@ Vimc has a few module parameters to configure the driver.
>
> param=value
>
> -* ``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).
> -
> * ``deb_mean_win_size=<unsigned int>``
>
> Window size to calculate the mean. Note: the window size needs to be an
> diff --git a/drivers/media/platform/vimc/vimc-scaler.c b/drivers/media/platform/vimc/vimc-scaler.c
> index 05db5070e268..1e398124a651 100644
> --- a/drivers/media/platform/vimc/vimc-scaler.c
> +++ b/drivers/media/platform/vimc/vimc-scaler.c
> @@ -12,25 +12,24 @@
>
> #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");
> +/* Pad identifier */
> +enum sca_pad {
> + SCA_SINK = 0,
> + SCA_SRC = 1,
> + SCA_COUNT = 2
> +};
>
> -#define IS_SINK(pad) (!pad)
> -#define IS_SRC(pad) (pad)
> -#define MAX_ZOOM 8
> +/* Default scaling factor for both width and height */
> +#define SRC_SCALING_DEFAULT 3

Normally a scaler defaults at a scale factor of 1. It doesn't
really make sense to default to another factor IMHO.

>
> struct vimc_sca_device {
> struct vimc_ent_device ved;
> struct v4l2_subdev sd;
> struct device *dev;
> - /* NOTE: the source fmt is the same as the sink
> - * with the width and hight multiplied by mult
> - */
> - struct v4l2_mbus_framefmt sink_fmt;
> + /* Frame format for both sink and src pad */
> + struct v4l2_mbus_framefmt fmt[SCA_COUNT];

This is one of the rare cases when I think using a define for the
array size makes the code actually less readable. Since there is
just one source and one sink, it makes perfect sense to just use 2
instead of SCA_COUNT. The name SCA_COUNT does not actually tell the
reader anything. I'd just drop it from the enum.

> /* Values calculated when the stream starts */
> u8 *src_frame;
> - unsigned int src_line_size;
> unsigned int bpp;
> };
>
> @@ -54,8 +53,8 @@ static int vimc_sca_init_cfg(struct v4l2_subdev *sd,
> for (i = 1; i < sd->entity.num_pads; i++) {
> mf = v4l2_subdev_get_try_format(sd, cfg, i);
> *mf = sink_fmt_default;
> - mf->width = mf->width * sca_mult;
> - mf->height = mf->height * sca_mult;
> + mf->width = mf->width * SRC_SCALING_DEFAULT;
> + mf->height = mf->height * SRC_SCALING_DEFAULT;
> }
>
> return 0;
> @@ -92,14 +91,8 @@ 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 (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;
> }
> @@ -111,82 +104,64 @@ static int vimc_sca_get_fmt(struct v4l2_subdev *sd,
> struct vimc_sca_device *vsca = v4l2_get_subdevdata(sd);
>
> /* Get the current sink format */
> - format->format = (format->which == V4L2_SUBDEV_FORMAT_TRY) ?
> - *v4l2_subdev_get_try_format(sd, cfg, 0) :
> - vsca->sink_fmt;
> -
> - /* Scale the frame size for the source pad */
> - if (IS_SRC(format->pad)) {
> - format->format.width = vsca->sink_fmt.width * sca_mult;
> - format->format.height = vsca->sink_fmt.height * sca_mult;
> - }
> + if (format->which == V4L2_SUBDEV_FORMAT_TRY)
> + format->format = *v4l2_subdev_get_try_format(sd, cfg,
> + format->pad);
> + else
> + format->format = vsca->fmt[format->pad];
>
> return 0;
> }
>
> -static void vimc_sca_adjust_sink_fmt(struct v4l2_mbus_framefmt *fmt)
> +static void vimc_sca_adjust_fmt(struct v4l2_mbus_framefmt *fmt[], __u32 pad)
> {
> - const struct vimc_pix_map *vpix;
> + if (pad == 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(fmt[SCA_SINK]->code);
> + if (!vpix || vpix->bayer)
> + fmt[SCA_SINK]->code = sink_fmt_default.code;
> + if (fmt[SCA_SINK]->field == V4L2_FIELD_ANY)
> + fmt[SCA_SINK]->field = sink_fmt_default.field;
> +
> + vimc_colorimetry_clamp(fmt[SCA_SINK]);
> + }
>
> - fmt->width = clamp_t(u32, fmt->width, VIMC_FRAME_MIN_WIDTH,
> + fmt[pad]->width = clamp_t(u32, fmt[pad]->width, VIMC_FRAME_MIN_WIDTH,
> VIMC_FRAME_MAX_WIDTH) & ~1;
> - fmt->height = clamp_t(u32, fmt->height, VIMC_FRAME_MIN_HEIGHT,
> + fmt[pad]->height = clamp_t(u32, fmt[pad]->height, VIMC_FRAME_MIN_HEIGHT,
> VIMC_FRAME_MAX_HEIGHT) & ~1;
>
> - if (fmt->field == V4L2_FIELD_ANY)
> - fmt->field = sink_fmt_default.field;
> -
> - vimc_colorimetry_clamp(fmt);
> + /* Assure src pad attributes besides dimensions are the same as sink */
> + fmt[SCA_SRC]->code = fmt[SCA_SINK]->code;
> + fmt[SCA_SRC]->field = fmt[SCA_SINK]->field;
> + fmt[SCA_SRC]->colorspace = fmt[SCA_SINK]->colorspace;
> }
>
> static int vimc_sca_set_fmt(struct v4l2_subdev *sd,
> struct v4l2_subdev_pad_config *cfg,
> - 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_mbus_framefmt *fmt[SCA_COUNT];
>
> - if (fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> + if (format->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;
> + fmt[SCA_SINK] = &vsca->fmt[SCA_SINK];
> + fmt[SCA_SRC] = &vsca->fmt[SCA_SRC];
> } else {
> - sink_fmt = v4l2_subdev_get_try_format(sd, cfg, 0);
> + fmt[SCA_SINK] = v4l2_subdev_get_try_format(sd, cfg, SCA_SINK);
> + fmt[SCA_SRC] = v4l2_subdev_get_try_format(sd, cfg, SCA_SRC);
> }
>
> - /*
> - * Do not change the format of the source pad,
> - * it is propagated from the sink
> - */
> - if (IS_SRC(fmt->pad)) {
> - fmt->format = *sink_fmt;
> - fmt->format.width = sink_fmt->width * sca_mult;
> - fmt->format.height = sink_fmt->height * sca_mult;
> - } else {
> - /* Set the new format in the sink pad */
> - vimc_sca_adjust_sink_fmt(&fmt->format);
> -
> - dev_dbg(vsca->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;
> - }
> + *fmt[format->pad] = format->format;
> + vimc_sca_adjust_fmt(fmt, format->pad);
> +
> + format->format = *fmt[format->pad];
>
> return 0;
> }
> @@ -211,16 +186,12 @@ 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[SCA_SINK].code);
> vsca->bpp = vpix->bpp;
>
> - /* Calculate the width in bytes of the src frame */
> - vsca->src_line_size = vsca->sink_fmt.width *
> - sca_mult * vsca->bpp;
> -
> /* Calculate the frame size of the source pad */
> - frame_size = vsca->src_line_size * vsca->sink_fmt.height *
> - sca_mult;
> + frame_size = vsca->fmt[SCA_SRC].width
> + * vsca->fmt[SCA_SRC].height * vsca->bpp;
>
> /* Allocate the frame buffer. Use vmalloc to be able to
> * allocate a large amount of memory
> @@ -249,73 +220,26 @@ 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,
> - const unsigned int lin, const unsigned int col,
> - const u8 *const sink_frame)
> -{
> - 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->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
> - */
> - index = VIMC_FRAME_INDEX(lin * sca_mult, col * sca_mult,
> - vsca->sink_fmt.width * sca_mult, vsca->bpp);
> -
> - dev_dbg(vsca->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->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)
> {
> - 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 = 0; i < vsca->sink_fmt.height; i++)
> - for (j = 0; j < vsca->sink_fmt.width; j++)
> - vimc_sca_scale_pix(vsca, i, j, sink_frame);
> + unsigned int lin, col, bpp_i, index;
> + struct v4l2_mbus_framefmt const *fmt = vsca->fmt;
> + u8 *walker = vsca->src_frame;
> +
> + /* Set each pixel at the src_frame to its sink_frame equivalent */
> + for (lin = 0; lin < fmt[SCA_SRC].height; lin++) {
> + for (col = 0; col < fmt[SCA_SRC].width; col++) {
> + index = VIMC_FRAME_INDEX((lin * fmt[SCA_SINK].height)
> + / fmt[SCA_SRC].height,
> + (col * fmt[SCA_SINK].width)
> + / fmt[SCA_SRC].width,
> + fmt[SCA_SINK].width,
> + vsca->bpp);
> + for (bpp_i = 0; bpp_i < vsca->bpp; bpp_i++)
> + *(walker++) = sink_frame[index + bpp_i];

This can be replaced with memcpy.

I assume that the input to the scaler is never a Bayer format, i.e. the
image was debayered first?

> + }
> + }

As a suggestion for a future patch: use the Coarse Bresenham scaling algorithm
to do the scaling (the v4l2 test pattern generator uses this).

This will give substantially better scaling results.

> }
>
> static void *vimc_sca_process_frame(struct vimc_ent_device *ved,
> @@ -382,7 +306,10 @@ struct vimc_ent_device *vimc_sca_add(struct vimc_device *vimc,
> vsca->dev = &vimc->pdev.dev;
>
> /* Initialize the frame format */
> - vsca->sink_fmt = sink_fmt_default;
> + vsca->fmt[SCA_SINK] = sink_fmt_default;
> + vsca->fmt[SCA_SRC] = sink_fmt_default;
> + vsca->fmt[SCA_SRC].width *= SRC_SCALING_DEFAULT;
> + vsca->fmt[SCA_SRC].height *= SRC_SCALING_DEFAULT;
>
> return &vsca->ved;
> }
>

Regards,

Hans