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    Subject[PATCH AUTOSEL 4.14 086/127] serial: uartps: Wait for tx_empty in console setup
    Date
    From: Raviteja Narayanam <raviteja.narayanam@xilinx.com>

    [ 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>
    ---
    drivers/tty/serial/xilinx_uartps.c | 8 ++++++++
    1 file changed, 8 insertions(+)

    diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
    index 81657f09761cd..00a740b8ad273 100644
    --- 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);
    }

    --
    2.25.1
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