On Wed, 11 Jan 2023 at 09:08, Pali Rohár pali@kernel.org wrote:
On Wednesday 11 January 2023 08:53:30 Loic Poulain wrote:
On Wed, 11 Jan 2023 at 00:53, Pali Rohár pali@kernel.org wrote:
On Tuesday 10 January 2023 20:24:06 Loic Poulain wrote:
The u-boot console may show some corrupted characters when printing in board_init() due to reset of the UART (probe) before the TX FIFO has been completely drained.
To fix this issue, and in case UART is still running, we now try to flush the FIFO before proceeding to UART reinitialization. For this we're waiting for Transmitter Complete bit, indicating that the FIFO and the shift register are empty.
flushing has a 4ms timeout guard, which is normally more than enough to consume the FIFO @ low baudrate (9600bps).
Signed-off-by: Loic Poulain loic.poulain@linaro.org Tested-by: Lothar Waßmann LW@KARO-electronics.de
Hello! Last time when I looked at this driver I was in impression that also _mxc_serial_setbrg() function requires calling some flush function at the beginning. Could you please check if it is needed or not? I'm really not sure.
_mxc_serial_setbrg is usually called after init, which now includes that flush.
I'm looking at it and this function is called also from mxc_serial_setbrg() callback, which is used by u-boot to change baudrate after the init.
Ok, good point, then it makes sense to add this guard here as well.