4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Alain Volmat <alain.volmat@xxxxxxxxxxx>
commit 03f25d53b145bc2f7ccc82fc04e4482ed734f524 upstream.
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
Tested-by: Alain Volmat <alain.volmat@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231009082450.452877-1-amelie.delaunay@xxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma/stm32-mdma.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -520,7 +520,7 @@ static int stm32_mdma_set_xfer_param(str
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));
@@ -948,7 +948,7 @@ stm32_mdma_prep_dma_memcpy(struct dma_ch
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));
