On Mon, Mar 13, 2017 at 08:16:25AM +0000, Russell King - ARM Linux wrote:
> On Sun, Mar 12, 2017 at 09:26:41PM -0700, Steve Longerbeam wrote:
> > On 03/12/2017 01:22 PM, Russell King - ARM Linux wrote:
> > >What I had was this patch for your v3.  I never got to testing your
> > >v4 because of the LP-11 problem.
> > >
> > >In v5, you've changed to propagate the ipu_cpmem_set_image() error
> > >code to avoid the resulting corruption, but that leaves the other bits
> > >of this patch unaddressed, along my "media: imx: smfc: add support
> > >for bayer formats" patch.
> > >
> > >Your driver basically has no support for bayer formats.
> > 
> > You added the patches to this driver that adds the bayer support,
> > I don't think there is anything more required of the driver at this
> > point to support bayer, the remaining work needs to happen in the IPUv3
> > driver.
> 
> There is more work, because the way you've merged my changes to
> imx_smfc_setup_channel() into csi_idmac_setup_channel() is wrong with
> respect to the burst size.
> 
> You always set it to 8 or 16 depending on the width:
> 
>       burst_size = (image.pix.width & 0xf) ? 8 : 16;
> 
>       ipu_cpmem_set_burstsize(priv->idmac_ch, burst_size);
> 
> and then you have my switch() statement which assigns burst_size.
> My _tested_ code removed the above, added the switch, which had
> a default case which reflected the above setting:
> 
>       default:
>               burst_size = (outfmt->width & 0xf) ? 8 : 16;
> 
> and then went on to set the burst size _after_ the switch statement:
> 
>       ipu_cpmem_set_burstsize(priv->smfc_ch, burst_size);
> 
> The effect is unchanged for non-bayer formats.  For bayer formats, the
> burst size is determined by the bayer data size.
> 
> So, even if it's appropriate to fix ipu_cpmem_set_image(), fixing the
> above is still required.
> 
> I'm not convinced that fixing ipu_cpmem_set_image() is even the best
> solution - it's not as trivial as it looks on the surface:
> 
>         ipu_cpmem_set_resolution(ch, image->rect.width, image->rect.height);
>         ipu_cpmem_set_stride(ch, pix->bytesperline);
> 
> this is fine, it doesn't depend on the format.  However, the next line:
> 
>         ipu_cpmem_set_fmt(ch, v4l2_pix_fmt_to_drm_fourcc(pix->pixelformat));
> 
> does - v4l2_pix_fmt_to_drm_fourcc() is a locally defined function (it
> isn't v4l2 code) that converts a v4l2 pixel format to a DRM fourcc.
> DRM knows nothing about bayer formats, there aren't fourcc codes in
> DRM for it.  The result is that v4l2_pix_fmt_to_drm_fourcc() returns
> -EINVAL cast to a u32, which gets passed unchecked into ipu_cpmem_set_fmt().
> 
> ipu_cpmem_set_fmt() won't recognise that, and also returns -EINVAL - and
> it's a bug that this is not checked and propagated.  If it is checked and
> propagated, then we need this to support bayer formats, and I don't see
> DRM people wanting bayer format fourcc codes added without there being
> a real DRM driver wanting to use them.
> 
> Then there's the business of calculating the top-left offset of the image,
> which for bayer always needs to be an even number of pixels - as this
> function takes the top-left offset, it ought to respect it, but if it
> doesn't meet this criteria, what should it do?  csi_idmac_setup_channel()
> always sets them to zero, but that's not really something that
> ipu_cpmem_set_image() should assume.

For the time being, I've restored the functionality along the same lines
as I originally had.  This seems to get me working capture, but might
break non-bayer passthrough mode:

diff --git a/drivers/staging/media/imx/imx-media-csi.c 
b/drivers/staging/media/imx/imx-media-csi.c
index fc0036aa84d0..df336971a009 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -314,14 +314,6 @@ static int csi_idmac_setup_channel(struct csi_priv *priv)
        image.phys0 = phys[0];
        image.phys1 = phys[1];
 
-       ret = ipu_cpmem_set_image(priv->idmac_ch, &image);
-       if (ret)
-               return ret;
-
-       burst_size = (image.pix.width & 0xf) ? 8 : 16;
-
-       ipu_cpmem_set_burstsize(priv->idmac_ch, burst_size);
-
        /*
         * Check for conditions that require the IPU to handle the
         * data internally as generic data, aka passthrough mode:
@@ -346,15 +338,29 @@ static int csi_idmac_setup_channel(struct csi_priv *priv)
                passthrough_bits = 16;
                break;
        default:
+               burst_size = (image.pix.width & 0xf) ? 8 : 16;
                passthrough = (sensor_ep->bus_type != V4L2_MBUS_CSI2 &&
                               sensor_ep->bus.parallel.bus_width >= 16);
                passthrough_bits = 16;
                break;
        }
 
-       if (passthrough)
+       if (passthrough) {
+               ipu_cpmem_set_resolution(priv->idmac_ch, image.rect.width,
+                                        image.rect.height);
+               ipu_cpmem_set_stride(priv->idmac_ch, image.pix.bytesperline);
+               ipu_cpmem_set_buffer(priv->idmac_ch, 0, image.phys0);
+               ipu_cpmem_set_buffer(priv->idmac_ch, 1, image.phys1);
+               ipu_cpmem_set_burstsize(priv->idmac_ch, burst_size);
                ipu_cpmem_set_format_passthrough(priv->idmac_ch,
                                                 passthrough_bits);
+       } else {
+               ret = ipu_cpmem_set_image(priv->idmac_ch, &image);
+               if (ret)
+                       return ret;
+
+               ipu_cpmem_set_burstsize(priv->idmac_ch, burst_size);
+       }
 
        /*
         * Set the channel for the direct CSI-->memory via SMFC


-- 
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