[PATCH 4.14 130/222] dmaengine: stm32-dma: fix incomplete configuration in cyclic mode

Greg Kroah-Hartman
2018-11-11T22:32:51Z

From: Pierre Yves MORDRET <pierre-yves.mordret@st.com>

commit e57cb3b3f10d005410f09d4598cc6d62b833f2b0 upstream.

When in cyclic mode, the configuration is updated after having started the
DMA hardware (STM32_DMA_SCR_EN) leading to incomplete configuration of
SMxAR registers.

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Hugues Fruchet <hugues.fruchet@st.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/dma/stm32-dma.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -429,6 +429,8 @@ static void stm32_dma_dump_reg(struct st
dev_dbg(chan2dev(chan), "SFCR: 0x%08x\n", sfcr);
}

+static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan);
+
static void stm32_dma_start_transfer(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
@@ -471,6 +473,9 @@ static void stm32_dma_start_transfer(str
if (status)
stm32_dma_irq_clear(chan, status);

+ if (chan->desc->cyclic)
+ stm32_dma_configure_next_sg(chan);
+
stm32_dma_dump_reg(chan);

/* Start DMA */
@@ -564,8 +569,7 @@ static void stm32_dma_issue_pending(stru
if (vchan_issue_pending(&chan->vchan) && !chan->desc && !chan->busy) {
dev_dbg(chan2dev(chan), "vchan %p: issued\n", &chan->vchan);
stm32_dma_start_transfer(chan);
- if (chan->desc->cyclic)
- stm32_dma_configure_next_sg(chan);
+
}
spin_unlock_irqrestore(&chan->vchan.lock, flags);
}