Re: [PATCH v3 27/33] omap3isp: Implement proper CCDC link validation, check pixel rate

Laurent Pinchart
2012-02-22T11:11:04Z

Hi Sakari,

Thanks for the patch.

On Monday 20 February 2012 03:57:06 Sakari Ailus wrote:
> Implement correct link validation for the CCDC. Use external_rate from
> isp_pipeline to configurat vp divisor and check that external_rate does not
> exceed our data rate limitations.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> ---
> drivers/media/video/omap3isp/ispccdc.c | 69
> +++++++++++++++++++++++++++++-- 1 files changed, 64 insertions(+), 5
> deletions(-)
>
> diff --git a/drivers/media/video/omap3isp/ispccdc.c
> b/drivers/media/video/omap3isp/ispccdc.c index 6aff241..1555891 100644
> --- a/drivers/media/video/omap3isp/ispccdc.c
> +++ b/drivers/media/video/omap3isp/ispccdc.c
> @@ -836,8 +836,8 @@ static void ccdc_config_vp(struct isp_ccdc_device *ccdc)
>
> if (pipe->input)
> div = DIV_ROUND_UP(l3_ick, pipe->max_rate);
> - else if (ccdc->vpcfg.pixelclk)
> - div = l3_ick / ccdc->vpcfg.pixelclk;
> + else if (pipe->external_rate)
> + div = l3_ick / pipe->external_rate;
>
> div = clamp(div, 2U, max_div);
> fmtcfg_vp |= (div - 2) << ISPCCDC_FMTCFG_VPIF_FRQ_SHIFT;
> @@ -1749,7 +1749,18 @@ static int ccdc_set_stream(struct v4l2_subdev *sd,
> int enable) }
>
> switch (enable) {
> - case ISP_PIPELINE_STREAM_CONTINUOUS:
> + case ISP_PIPELINE_STREAM_CONTINUOUS: {
> + struct isp_pipeline *pipe = to_isp_pipeline(&sd->entity);
> + unsigned int rate = UINT_MAX;
> +
> + /*
> + * Check that maximum allowed rate isn't exceeded by
> + * the pixel rate.
> + */
> + omap3isp_ccdc_max_rate(&isp->isp_ccdc, &rate);
> + if (pipe->external_rate > rate)
> + return -ENOSPC;
> +

What about checking this at pipeline validation time ?

> if (ccdc->output & CCDC_OUTPUT_MEMORY)
> omap3isp_sbl_enable(isp, OMAP3_ISP_SBL_CCDC_WRITE);
>
> @@ -1758,6 +1769,7 @@ static int ccdc_set_stream(struct v4l2_subdev *sd, int
> enable)
>
> ccdc->underrun = 0;
> break;
> + }
>
> case ISP_PIPELINE_STREAM_SINGLESHOT:
> if (ccdc->output & CCDC_OUTPUT_MEMORY &&
> @@ -1999,6 +2011,37 @@ static int ccdc_set_format(struct v4l2_subdev *sd,
> struct v4l2_subdev_fh *fh, return 0;
> }
>
> +/*
> + * Decide whether desired output pixel code can be obtained with
> + * the lane shifter by shifting the input pixel code.
> + * @in: input pixelcode to shifter
> + * @out: output pixelcode from shifter
> + * @additional_shift: # of bits the sensor's LSB is offset from CAMEXT[0]
> + *
> + * return true if the combination is possible
> + * return false otherwise
> + */
> +static bool ccdc_is_shiftable(enum v4l2_mbus_pixelcode in,
> + enum v4l2_mbus_pixelcode out,
> + unsigned int additional_shift)
> +{
> + const struct isp_format_info *in_info, *out_info;
> +
> + if (in == out)
> + return true;
> +
> + in_info = omap3isp_video_format_info(in);
> + out_info = omap3isp_video_format_info(out);
> +
> + if ((in_info->flavor == 0) || (out_info->flavor == 0))
> + return false;
> +
> + if (in_info->flavor != out_info->flavor)
> + return false;
> +
> + return in_info->bpp - out_info->bpp + additional_shift <= 6;
> +}
> +
> static int ccdc_link_validate(struct v4l2_subdev *sd,
> struct media_link *link,
> struct v4l2_subdev_format *source_fmt,
> @@ -2008,13 +2051,31 @@ static int ccdc_link_validate(struct v4l2_subdev
> *sd, struct isp_pipeline *pipe = to_isp_pipeline(&ccdc->subdev.entity); int
> rval;
>
> + /* Check if the two ends match */
> + if (source_fmt->format.width != sink_fmt->format.width ||
> + source_fmt->format.height != sink_fmt->format.height)
> + return -EPIPE;
> +
> /* We've got a parallel sensor here. */
> if (ccdc->input == CCDC_INPUT_PARALLEL) {

The lane shifter is usable with the CCP2 and CSI2 inputs as well. The
parallel_shift value is restricted to parallel input though. Please perform
the same check as done in isp_video_validate_pipeline().

Revies would also be easier if you removed the CCDC-specific code from
isp_video_validate_pipeline() in this patch.

> + struct isp_parallel_platform_data *pdata =
> + &((struct isp_v4l2_subdevs_group *)
> + media_entity_to_v4l2_subdev(link->source->entity)
> + ->host_priv)->bus.parallel;
> + unsigned long parallel_shift = pdata->data_lane_shift * 2;
> + /* Lane shifter may be used to drop bits on CCDC sink pad */
> + if (!ccdc_is_shiftable(source_fmt->format.code,
> + sink_fmt->format.code, parallel_shift))
> + return -EPIPE;
> +
> pipe->external =
> media_entity_to_v4l2_subdev(link->source->entity);
> rval = omap3isp_get_external_info(pipe, link);
> if (rval < 0)
> return 0;
> + } else {
> + if (source_fmt->format.code != sink_fmt->format.code)
> + return -EPIPE;
> }
>
> return 0;
> @@ -2299,8 +2360,6 @@ int omap3isp_ccdc_init(struct isp_device *isp)
> ccdc->clamp.oblen = 0;
> ccdc->clamp.dcsubval = 0;
>
> - ccdc->vpcfg.pixelclk = 0;
> -
> ccdc->update = OMAP3ISP_CCDC_BLCLAMP;
> ccdc_apply_controls(ccdc);
--
Regards,

Laurent Pinchart