Messages in this thread | | | Date | Wed, 08 Apr 2020 17:50:32 +0200 | From | Maarten Brock <> | Subject | Re: [PATCH] serial: uartps: Wait for tx_empty in console setup |
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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@xilinx.com> > --- > 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
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