diff options
| author | Hans Verkuil <hverkuil@xs4all.nl> | 2019-08-09 10:32:40 +0200 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2019-08-09 16:33:41 +0530 |
| commit | d555c34338cae844b207564c482e5a3fb089d25e (patch) | |
| tree | 896e40b9cdd7fdbcdfd524a732daccab82beaa5d /drivers/dma | |
| parent | 39c71a5b8212f4b502d9a630c6706ac723abd422 (diff) | |
| download | linux-d555c34338cae844b207564c482e5a3fb089d25e.tar.bz2 | |
omap-dma/omap_vout_vrfb: fix off-by-one fi value
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>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Link: https://lore.kernel.org/r/952e7f51-f208-9333-6f58-b7ed20d2ea0b@xs4all.nl
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/ti/omap-dma.c | 4 |
1 files changed, 2 insertions, 2 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; |