[PATCH 4/4] serial: stm32: correct loop for dma error handling

From: Valentin Caron
Date: Tue Jan 04 2022 - 13:26:12 EST


In this error handling, "transmit_chars_dma" function will call
"transmit_chars_pio" once per characters. But "transmit_chars_pio" will
continue to send characters while xmit buffer is not empty.

Remove this useless loop, one call is sufficient.

Signed-off-by: Valentin Caron <valentin.caron@xxxxxxxxxxx>
---
drivers/tty/serial/stm32-usart.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 788e002688f2..1f89ab0e49ac 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -477,7 +477,7 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port)
const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
struct circ_buf *xmit = &port->state->xmit;
struct dma_async_tx_descriptor *desc = NULL;
- unsigned int count, i;
+ unsigned int count;

if (stm32_usart_tx_dma_started(stm32port)) {
if (!stm32_usart_tx_dma_enabled(stm32port))
@@ -542,8 +542,7 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port)
return;

fallback_err:
- for (i = count; i > 0; i--)
- stm32_usart_transmit_chars_pio(port);
+ stm32_usart_transmit_chars_pio(port);
}

static void stm32_usart_transmit_chars(struct uart_port *port)
--
2.17.1