serial: uartps: Wait for tx_empty in console setup

[ Upstream commit 42e11948ddf68b9f799cad8c0ddeab0a39da33e8 ]

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@xilinx.com>
Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/1586413563-29125-2-git-send-email-raviteja.narayanam@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 81657f09761cd764dfe8faa1d7552a54aac6a5bf..00a740b8ad2736182768c43c7d400f6b5180c791 100644 (file)
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1282,6 +1282,7 @@ static int cdns_uart_console_setup(struct console *co, char *options)
        int bits = 8;
        int parity = 'n';
        int flow = 'n';
+       unsigned long time_out;
 
        if (co->index < 0 || co->index >= CDNS_UART_NR_PORTS)
                return -EINVAL;
@@ -1295,6 +1296,13 @@ 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 */
+       time_out = jiffies + usecs_to_jiffies(TX_TIMEOUT);
+
+       while (time_before(jiffies, time_out) &&
+              cdns_uart_tx_empty(port) != TIOCSER_TEMT)
+               cpu_relax();
+
        return uart_set_options(port, co, baud, parity, bits, flow);
 }