[v4,11/18] dmaengine: dma-jz4780: Add missing residue DTC mask
diff mbox series

Message ID 20180807114218.20091-12-paul@crapouillou.net
State Changes Requested
Headers show
Series
  • JZ47xx DMA patchset v4
Related show

Commit Message

Paul Cercueil Aug. 7, 2018, 11:42 a.m. UTC
From: Daniel Silsby <dansilsby@gmail.com>

The 'dtc' word in jz DMA descriptors contains two fields: The
lowest 24 bits are the transfer count, and upper 8 bits are the DOA
offset to next descriptor. The upper 8 bits are now correctly masked
off when computing residue in jz4780_dma_desc_residue(). Note that
reads of the DTCn hardware reg are automatically masked this way.

Signed-off-by: Daniel Silsby <dansilsby@gmail.com>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Mathieu Malaterre <malat@debian.org>
---
 drivers/dma/dma-jz4780.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

 v2: No change

 v3: No change

 v4: Add my Signed-off-by

Comments

Vinod Koul Aug. 27, 2018, 5 a.m. UTC | #1
On 07-08-18, 13:42, Paul Cercueil wrote:
> From: Daniel Silsby <dansilsby@gmail.com>
> 
> The 'dtc' word in jz DMA descriptors contains two fields: The
> lowest 24 bits are the transfer count, and upper 8 bits are the DOA
> offset to next descriptor. The upper 8 bits are now correctly masked
> off when computing residue in jz4780_dma_desc_residue(). Note that
> reads of the DTCn hardware reg are automatically masked this way.
> 
> Signed-off-by: Daniel Silsby <dansilsby@gmail.com>
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> Tested-by: Mathieu Malaterre <malat@debian.org>
> ---
>  drivers/dma/dma-jz4780.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
>  v2: No change
> 
>  v3: No change
> 
>  v4: Add my Signed-off-by
> 
> diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c
> index 3a4d0a4b550d..a4292ac4c686 100644
> --- a/drivers/dma/dma-jz4780.c
> +++ b/drivers/dma/dma-jz4780.c
> @@ -616,7 +616,8 @@ static size_t jz4780_dma_desc_residue(struct jz4780_dma_chan *jzchan,
>  	residue = 0;
>  
>  	for (i = next_sg; i < desc->count; i++)
> -		residue += desc->desc[i].dtc << jzchan->transfer_shift;
> +		residue += (desc->desc[i].dtc & 0xffffff) <<

GENMASK(23, 0) please.

Patch
diff mbox series

diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c
index 3a4d0a4b550d..a4292ac4c686 100644
--- a/drivers/dma/dma-jz4780.c
+++ b/drivers/dma/dma-jz4780.c
@@ -616,7 +616,8 @@  static size_t jz4780_dma_desc_residue(struct jz4780_dma_chan *jzchan,
 	residue = 0;
 
 	for (i = next_sg; i < desc->count; i++)
-		residue += desc->desc[i].dtc << jzchan->transfer_shift;
+		residue += (desc->desc[i].dtc & 0xffffff) <<
+			jzchan->transfer_shift;
 
 	if (next_sg != 0) {
 		count = jz4780_dma_chn_readl(jzdma, jzchan->id,