From: Raviteja Narayanam <raviteja.narayanam@xilinx.com>
To: linux-serial@vger.kernel.org
Cc: gregkh@linuxfoundation.org, jslaby@suse.com,
michal.simek@xilinx.com, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, git@xilinx.com,
Raviteja Narayanam <raviteja.narayanam@xilinx.com>
Subject: [PATCH] serial: uartps: Wait for tx_empty in console setup
Date: Tue, 7 Apr 2020 22:23:11 +0530 [thread overview]
Message-ID: <1586278391-9061-1-git-send-email-raviteja.narayanam@xilinx.com> (raw)
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 */
--
2.7.4
next reply other threads:[~2020-04-07 16:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-07 16:53 Raviteja Narayanam [this message]
2020-04-08 7:13 ` [PATCH] serial: uartps: Wait for tx_empty in console setup Shubhrajyoti Datta
2020-04-08 15:50 ` Maarten Brock
2020-04-09 5:39 ` Raviteja Narayanam
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