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Commit 36512866 authored by Alain Volmat's avatar Alain Volmat Committed by Greg Kroah-Hartman
Browse files

dmaengine: stm32-mdma: correct desc prep when channel running 



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: a4ffb13c ("dmaengine: Add STM32 MDMA driver")
Signed-off-by: default avatarAlain Volmat <alain.volmat@foss.st.com>
Signed-off-by: default avatarAmelie Delaunay <amelie.delaunay@foss.st.com>
Cc: stable@vger.kernel.org
Tested-by: default avatarAlain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/20231009082450.452877-1-amelie.delaunay@foss.st.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4a5c267d

drivers/dma/stm32-mdma.c

+2 −2
Original line number Diff line number Diff line
@@ -510,7 +510,7 @@ 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));
@@ -938,7 +938,7 @@ 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));