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-rw-r--r--drivers/serial/serial_stm32.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/serial/serial_stm32.c b/drivers/serial/serial_stm32.c
index 0085113f67..23d476fba2 100644
--- a/drivers/serial/serial_stm32.c
+++ b/drivers/serial/serial_stm32.c
@@ -22,6 +22,14 @@
#include "serial_stm32.h"
#include <dm/device_compat.h>
+/*
+ * At 115200 bits/s
+ * 1 bit = 1 / 115200 = 8,68 us
+ * 8 bits = 69,444 us
+ * 10 bits are needed for worst case (8 bits + 1 start + 1 stop) = 86.806 us
+ */
+#define ONE_BYTE_B115200_US 87
+
static void _stm32_serial_setbrg(fdt_addr_t base,
struct stm32_uart_info *uart_info,
u32 clock_rate,
@@ -209,12 +217,10 @@ static int stm32_serial_probe(struct udevice *dev)
* before uart initialization, wait for TC bit (Transmission Complete)
* in case there is still chars from previous bootstage to transmit
*/
- ret = read_poll_timeout(readl, isr, isr & USART_ISR_TC, 10, 150,
- plat->base + ISR_OFFSET(stm32f4));
- if (ret) {
- clk_disable(&clk);
- return ret;
- }
+ ret = read_poll_timeout(readl, isr, isr & USART_ISR_TC, 50,
+ 16 * ONE_BYTE_B115200_US, plat->base + ISR_OFFSET(stm32f4));
+ if (ret)
+ dev_dbg(dev, "FIFO not empty, some character can be lost (%d)\n", ret);
ret = reset_get_by_index(dev, 0, &reset);
if (!ret) {