[PATCH v4 11/18] dmaengine: dma-jz4780: Add missing residue DTC mask

Paul Cercueil
2018-08-07T11:42:11Z

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) <<
+ jzchan->transfer_shift;

if (next_sg != 0) {
count = jz4780_dma_chn_readl(jzdma, jzchan->id,
--
2.11.0