[PATCH] omap-dma/omap_vout_vrfb: fix off-by-one fi value

[PATCH] omap-dma/omap_vout_vrfb: fix off-by-one fi value

[Hans Verkuil]

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@xs4all.nl>
---
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));

 	xt->src_start = vout->buf_phy_addr[vb->i];
 	xt->dst_start = vout->vrfb_context[vb->i].paddr[0];
-- 
2.20.1

Re: [PATCH] omap-dma/omap_vout_vrfb: fix off-by-one fi value

[Laurent Pinchart]

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@xs4all.nl>
> ---
> 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@ideasonboard.com>

> 
>  	xt->src_start = vout->buf_phy_addr[vb->i];
>  	xt->dst_start = vout->vrfb_context[vb->i].paddr[0];

-- 
Regards,

Laurent Pinchart

Re: [PATCH] omap-dma/omap_vout_vrfb: fix off-by-one fi value

[Peter Ujfalusi]

Hans,

On 30/07/2019 9.14, 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.

Thanks for catching it. I have implemented the interleaved support based
on the omap_vout_vrfb driver's behavior and hence I have missed the + 1
in the omap-dma.

Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>

> 
> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
> ---
> 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));
> 
>  	xt->src_start = vout->buf_phy_addr[vb->i];
>  	xt->dst_start = vout->vrfb_context[vb->i].paddr[0];
> 

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