This is an automated email from the ASF dual-hosted git repository.
xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/nuttx.git
The following commit(s) were added to refs/heads/master by this push:
new 6c186b6084 stm32h7:serial make TX DMA busy when there are an
outstanding transaction
6c186b6084 is described below
commit 6c186b6084e0952f29aaca0ea8296451b8646a72
Author: David Sidrane <[email protected]>
AuthorDate: Thu Jan 18 07:18:01 2024 -0800
stm32h7:serial make TX DMA busy when there are an outstanding transaction
If a TX DMA completion interrups a forground write.
The TX DMA completion can start a dma_send and it will
then followed by the forground write's dma_send
stoping the,then in progress DMA.
By atomicaly marking the tx dma busy, the forground
write will not perform the dma_send, and will only
enqueue the data. At the next TX dma completion any
data pending in the tx queue will be sent
---
arch/arm/src/stm32h7/stm32_serial.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/arm/src/stm32h7/stm32_serial.c
b/arch/arm/src/stm32h7/stm32_serial.c
index 22efa0d147..dffca7cc96 100644
--- a/arch/arm/src/stm32h7/stm32_serial.c
+++ b/arch/arm/src/stm32h7/stm32_serial.c
@@ -3356,13 +3356,17 @@ static void up_dma_txcallback(DMA_HANDLE handle,
uint8_t status, void *arg)
static void up_dma_txavailable(struct uart_dev_s *dev)
{
struct up_dev_s *priv = (struct up_dev_s *)dev->priv;
+ irqstate_t flags = enter_critical_section();
/* Only send when the DMA is idle */
- if (stm32_dmaresidual(priv->txdma) == 0)
+ if ((priv->dev.dmatx.length && priv->dev.dmatx.nlength) == 0 &&
+ stm32_dmaresidual(priv->txdma) == 0)
{
uart_xmitchars_dma(dev);
}
+
+ leave_critical_section(flags);
}
#endif
