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 v2 1/2] serial: uartps: Wait for tx_empty in console setup
Date: Thu, 9 Apr 2020 11:56:02 +0530 [thread overview]
Message-ID: <1586413563-29125-2-git-send-email-raviteja.narayanam@xilinx.com> (raw)
In-Reply-To: <1586413563-29125-1-git-send-email-raviteja.narayanam@xilinx.com>
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 | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 6b26f76..0bf946b 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1260,6 +1260,7 @@ 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 (!port->membase) {
pr_debug("console on " CDNS_UART_TTY_NAME "%i not present\n",
@@ -1270,6 +1271,13 @@ 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);
}
#endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */
--
2.7.4
next prev parent reply other threads:[~2020-04-09 6:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-09 6:26 [PATCH v2 0/2] serial: uartps: Add tx_empty checks Raviteja Narayanam
2020-04-09 6:26 ` Raviteja Narayanam [this message]
2020-04-09 6:26 ` [PATCH v2 2/2] serial: uartps: Use cdns_uart_tx_empty in console_write Raviteja Narayanam
2020-04-13 10:00 ` [PATCH v2 0/2] serial: uartps: Add tx_empty checks Shubhrajyoti Datta
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