From: Alain Volmat <alain.volmat@xxxxxxxxxxx>
In case of the prep descriptor while the channel is already running, the
CCR register value stored into the channel could already have its EN bit
set. This would lead to a bad transfer since, at start transfer time,
enabling the channel while other registers aren't yet properly set.
To avoid this, ensure to mask the CCR_EN bit when storing the ccr value
into the mdma channel structure.
Fixes: a4ffb13c8946 ("dmaengine: Add STM32 MDMA driver")
Signed-off-by: Alain Volmat <alain.volmat@xxxxxxxxxxx>
Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/dma/stm32-mdma.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index bae08b3f55c7..f414efdbd809 100644
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -489,7 +489,7 @@ static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
src_maxburst = chan->dma_config.src_maxburst;
dst_maxburst = chan->dma_config.dst_maxburst;
- ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+ ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id)) & ~STM32_MDMA_CCR_EN;
ctcr = stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id));
ctbr = stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id));
@@ -965,7 +965,7 @@ stm32_mdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
if (!desc)
return NULL;
- ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+ ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id)) & ~STM32_MDMA_CCR_EN;
ctcr = stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id));
ctbr = stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id));
cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id));
--
2.25.1
