Rework stm32_usart_console_putchar() function in order to anticipate
the case where the character can never be sent.
Signed-off-by: Valentin Caron <valentin.caron@xxxxxxxxxxx>
---
drivers/tty/serial/stm32-usart.c | 12 +++++++++---
drivers/tty/serial/stm32-usart.h | 2 ++
2 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 87b5cd4c9743..83895da84891 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -1645,10 +1645,16 @@ static void stm32_usart_console_putchar(struct uart_port *port, unsigned char ch
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+ u32 isr;
+ int ret;
- while (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
- cpu_relax();
-
+ ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, isr,
+ (isr & USART_SR_TXE), 100,
+ STM32_USART_TIMEOUT_USEC);
+ if (ret != 0) {
+ dev_err(port->dev, "Error while sending data in UART TX : %d\n", ret);
+ return;
+ }
writel_relaxed(ch, port->membase + ofs->tdr);
}
diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h
index feab952aec16..d734c4a5fd24 100644
--- a/drivers/tty/serial/stm32-usart.h
+++ b/drivers/tty/serial/stm32-usart.h
@@ -251,6 +251,8 @@ struct stm32_usart_info stm32h7_info = {
#define RX_BUF_P (RX_BUF_L / 2) /* dma rx buffer period */
#define TX_BUF_L RX_BUF_L /* dma tx buffer length */
+#define STM32_USART_TIMEOUT_USEC USEC_PER_SEC /* 1s timeout in µs */
+
struct stm32_port {
struct uart_port port;
struct clk *clk;
--
2.25.1
