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ar71xx: serial: core: add support for boot console with arbitrary baud rates

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The Arduino Yun uses a baud rate of 250000 by default. The serial is
going over the Atmel ATmega and is used to connect to this chip.
Without this patch Linux wants to switch the console to 230400 Baud.

With this patch Linux will use the configured baud rate and not some
standard one which is near by.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

SVN-Revision: 47450
This commit is contained in:
Hauke Mehrtens 2015-11-10 23:11:10 +00:00
parent abea1127c9
commit 1bfbf2de6d
1 changed files with 76 additions and 0 deletions
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76
target/linux/ar71xx/patches-4.1/821-serial-core-add-support-for-boot-console-with-arbitr.patch Normal file
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@ -0,0 +1,76 @@
From 4d3c17975c7814884a721fe693b3adf5c426d759 Mon Sep 17 00:00:00 2001
From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Tue, 10 Nov 2015 22:18:39 +0100
Subject: [RFC] serial: core: add support for boot console with arbitrary
baud rates
The Arduino Yun uses a baud rate of 250000 by default. The serial is
going over the Atmel ATmega and is used to connect to this chip.
Without this patch Linux wants to switch the console to 230400 Baud.
With this patch Linux will use the configured baud rate and not some
standard one which is near by.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
---
drivers/tty/serial/serial_core.c | 13 ++++++++++---
include/linux/console.h | 1 +
2 files changed, 11 insertions(+), 3 deletions(-)
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -164,6 +164,8 @@ static int uart_port_startup(struct tty_
if (retval == 0) {
if (uart_console(uport) && uport->cons->cflag) {
tty->termios.c_cflag = uport->cons->cflag;
+ tty->termios.c_ospeed = uport->cons->baud;
+ tty->termios.c_ispeed = uport->cons->baud;
uport->cons->cflag = 0;
}
/*
@@ -1901,7 +1903,7 @@ static const struct baud_rates baud_rate
{ 4800, B4800 },
{ 2400, B2400 },
{ 1200, B1200 },
- { 0, B38400 }
+ { 0, BOTHER }
};
/**
@@ -1940,10 +1942,13 @@ uart_set_options(struct uart_port *port,
* Construct a cflag setting.
*/
for (i = 0; baud_rates[i].rate; i++)
- if (baud_rates[i].rate <= baud)
+ if (baud_rates[i].rate == baud)
break;
termios.c_cflag |= baud_rates[i].cflag;
+ if (!baud_rates[i].rate) {
+ termios.c_ospeed = baud;
+ }
if (bits == 7)
termios.c_cflag |= CS7;
@@ -1973,8 +1978,10 @@ uart_set_options(struct uart_port *port,
* Allow the setting of the UART parameters with a NULL console
* too:
*/
- if (co)
+ if (co) {
co->cflag = termios.c_cflag;
+ co->baud = baud;
+ }
return 0;
}
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -127,6 +127,7 @@ struct console {
short flags;
short index;
int cflag;
+ int baud;
void *data;
struct console *next;
};