On 2020-04-07 18:53, Raviteja Narayanam wrote:
On some platforms, the log is corrupted while console is being
registered. It is observed that when set_termios is called, there
are still some bytes in the FIFO to be transmitted.
So, wait for tx_empty inside cdns_uart_console_setup before
calling set_termios.
Signed-off-by: Raviteja Narayanam <raviteja.narayanam@xxxxxxxxxx>
---
drivers/tty/serial/xilinx_uartps.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/tty/serial/xilinx_uartps.c
b/drivers/tty/serial/xilinx_uartps.c
index 6b26f76..23468ff 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1260,6 +1260,8 @@ static int cdns_uart_console_setup(struct
console *co, char *options)
int bits = 8;
int parity = 'n';
int flow = 'n';
+ unsigned long time_out = jiffies + usecs_to_jiffies(TX_TIMEOUT);
+ int status;
if (!port->membase) {
pr_debug("console on " CDNS_UART_TTY_NAME "%i not present\n",
@@ -1270,6 +1272,14 @@ static int cdns_uart_console_setup(struct
console *co, char *options)
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
+ /* Wait for tx_empty before setting up the console */
+ while (time_before(jiffies, time_out)) {
+ status = cdns_uart_tx_empty(port);
+ if (status == TIOCSER_TEMT)
+ break;
+ cpu_relax();
+ }
+
return uart_set_options(port, co, baud, parity, bits, flow);
}
#endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */
You could do without the status variable. You could even combine the
while and if conditions.
And while you're at it, you might as well also rewrite the lines
1236-1238 to also use cdns_uart_tx_empty() for clarity.
Maarten
