Hi Hans,
Thank you for the patch.
On Tue, Jul 30, 2019 at 08:14:19AM +0200, Hans Verkuil wrote:
> The OMAP 4 TRM specifies that when using double-index addressing
> the address increases by the ES plus the EI value minus 1 within
> a frame. When a full frame is transferred, the address increases
> by the ES plus the frame index (FI) value minus 1.
>
> The omap-dma code didn't account for the 'minus 1' in the FI register.
> To get correct addressing, add 1 to the src_icg value.
>
> This was found when testing a hacked version of the media m2m-deinterlace.c
> driver on a Pandaboard.
>
> The only other source that uses this feature is omap_vout_vrfb.c,
> and that adds a + 1 when setting the dst_icg. This is a workaround
> for the broken omap-dma.c behavior. So remove the workaround at the
> same time that we fix omap-dma.c.
>
> I tested the omap_vout driver with a Beagle XM board to check that
> the '+ 1' in omap_vout_vrfb.c was indeed a workaround for the omap-dma
> bug.
>
> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
> ---
> It makes sense that this patch goes in through the dmaengine subsystem
> (Mauro, can you Ack this patch?), but if preferred it can also go in
> through the media subsystem if we get an Ack.
>
> Regards,
>
> Hans
> ---
> drivers/dma/ti/omap-dma.c | 4 ++--
> drivers/media/platform/omap/omap_vout_vrfb.c | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
> index ba2489d4ea24..ba27802efcd0 100644
> --- a/drivers/dma/ti/omap-dma.c
> +++ b/drivers/dma/ti/omap-dma.c
> @@ -1234,7 +1234,7 @@ static struct dma_async_tx_descriptor *omap_dma_prep_dma_interleaved(
> if (src_icg) {
> d->ccr |= CCR_SRC_AMODE_DBLIDX;
> d->ei = 1;
> - d->fi = src_icg;
> + d->fi = src_icg + 1;
> } else if (xt->src_inc) {
> d->ccr |= CCR_SRC_AMODE_POSTINC;
> d->fi = 0;
> @@ -1249,7 +1249,7 @@ static struct dma_async_tx_descriptor *omap_dma_prep_dma_interleaved(
> if (dst_icg) {
> d->ccr |= CCR_DST_AMODE_DBLIDX;
> sg->ei = 1;
> - sg->fi = dst_icg;
> + sg->fi = dst_icg + 1;
> } else if (xt->dst_inc) {
> d->ccr |= CCR_DST_AMODE_POSTINC;
> sg->fi = 0;
> diff --git a/drivers/media/platform/omap/omap_vout_vrfb.c b/drivers/media/platform/omap/omap_vout_vrfb.c
> index 29e3f5da59c1..729b1bf9395f 100644
> --- a/drivers/media/platform/omap/omap_vout_vrfb.c
> +++ b/drivers/media/platform/omap/omap_vout_vrfb.c
> @@ -254,7 +254,7 @@ int omap_vout_prepare_vrfb(struct omap_vout_device *vout,
>
> pixsize = vout->bpp * vout->vrfb_bpp;
> dst_icg = ((MAX_PIXELS_PER_LINE * pixsize) -
> - (vout->pix.width * vout->bpp)) + 1;
> + (vout->pix.width * vout->bpp));
You can remove the outer parentheses. Apart from that the patch looks OK
to me, it matches the documentation.
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>
> xt->src_start = vout->buf_phy_addr[vb->i];
> xt->dst_start = vout->vrfb_context[vb->i].paddr[0];
--
Regards,
Laurent Pinchart
