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x86, setup: Make the setup code also accept console=uart8250

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Make the boot code also accept the console=uart8250,io,0x2f8,115200n
form of early console.

Also add back simple_guess_base(), otherwise those simple_strtoull(,,0)
are not going to work.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4C3CCE05.4090505@kernel.org>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Yinghai Lu
2010-07-13 13:35:17 -07:00
committed by H. Peter Anvin
parent fa97bdf927
commit ce0aa5dd20
2 changed files with 80 additions and 1 deletions
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59
arch/x86/boot/tty.c
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@@ -170,7 +170,7 @@ static void early_serial_init(int baud)
outb(c & ~DLAB, early_serial_base + LCR);
}
void console_init(void)
static int parse_earlyprintk(void)
{
int baud = DEFAULT_BAUD;
char arg[32];
@@ -208,6 +208,63 @@ void console_init(void)
baud = DEFAULT_BAUD;
}
return baud;
}
#define BASE_BAUD (1843200/16)
static unsigned int probe_baud(int port)
{
unsigned char lcr, dll, dlh;
unsigned int quot;
lcr = inb(port + LCR);
outb(lcr | DLAB, port + LCR);
dll = inb(port + DLL);
dlh = inb(port + DLH);
outb(lcr, port + LCR);
quot = (dlh << 8) | dll;
return BASE_BAUD / quot;
}
static int parse_console_uart8250(void)
{
char optstr[64], *options;
int baud = DEFAULT_BAUD;
/*
* console=uart8250,io,0x3f8,115200n8
* need to make sure it is last one console !
*/
if (cmdline_find_option("console", optstr, sizeof optstr) <= 0)
return baud;
options = optstr;
if (!strncmp(options, "uart8250,io,", 12))
early_serial_base = simple_strtoull(options + 12, &options, 0);
else if (!strncmp(options, "uart,io,", 8))
early_serial_base = simple_strtoull(options + 8, &options, 0);
else
return baud;
if (options && (options[0] == ','))
baud = simple_strtoull(options + 1, &options, 0);
else
baud = probe_baud(early_serial_base);
return baud;
}
void console_init(void)
{
int baud;
baud = parse_earlyprintk();
if (!early_serial_base)
baud = parse_console_uart8250();
if (early_serial_base != 0)
early_serial_init(baud);
}