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

Sakari Ailus
2012-02-25T01:42:30Z

Hi Laurent,

Thanks for your comments.

On Wed, Feb 22, 2012 at 12:11:07PM +0100, Laurent Pinchart wrote:
> 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 the external entity is found before pipeline validation, then I can move
this there. I agree in principle that's the right thing to do.

> > 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().

Good catch. I'll fix this.

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

Ok. I see what I could do for the next version.

> > + 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

--
Sakari Ailus
e-mail: sakari.ailus@iki.fi jabber/XMPP/Gmail: sailus@retiisi.org.uk