| Message ID | 20231009082450.452877-1-amelie.delaunay@foss.st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dmaengine: stm32-mdma: correct desc prep when channel running | expand |
Hi Amélie, thanks a lot. Tested-by: Alain Volmat <alain.volmat@foss.st.com> Regards, Alain On Mon, Oct 09, 2023 at 10:24:50AM +0200, Amelie Delaunay wrote: > From: Alain Volmat <alain.volmat@foss.st.com> > > 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@foss.st.com> > Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com> > Cc: stable@vger.kernel.org > --- > 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 >
On 09-10-23, 11:02, Alain Volmat wrote: > Hi Amélie, > > thanks a lot. > > Tested-by: Alain Volmat <alain.volmat@foss.st.com> Please **do ** not ** top post! > > Regards, > Alain > > On Mon, Oct 09, 2023 at 10:24:50AM +0200, Amelie Delaunay wrote: > > From: Alain Volmat <alain.volmat@foss.st.com> > > > > 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@foss.st.com> > > Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com> > > Cc: stable@vger.kernel.org > > --- > > 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 > >
On Mon, 09 Oct 2023 10:24:50 +0200, Amelie Delaunay wrote: > 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. > > [...] Applied, thanks! [1/1] dmaengine: stm32-mdma: correct desc prep when channel running commit: 03f25d53b145bc2f7ccc82fc04e4482ed734f524 Best regards,
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));