mirror of
https://github.com/torvalds/linux.git
synced 2024-11-13 23:51:39 +00:00
74b3c444a9
earlyprintk can take and I/O port, so we need to handle this case in the setup code too, otherwise 0x3f8 will be treated as a baud rate. Signed-off-by: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <4C7B05A6.4010801@kernel.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
152 lines
3.4 KiB
C
152 lines
3.4 KiB
C
#include "boot.h"
|
|
|
|
#define DEFAULT_SERIAL_PORT 0x3f8 /* ttyS0 */
|
|
|
|
#define XMTRDY 0x20
|
|
|
|
#define DLAB 0x80
|
|
|
|
#define TXR 0 /* Transmit register (WRITE) */
|
|
#define RXR 0 /* Receive register (READ) */
|
|
#define IER 1 /* Interrupt Enable */
|
|
#define IIR 2 /* Interrupt ID */
|
|
#define FCR 2 /* FIFO control */
|
|
#define LCR 3 /* Line control */
|
|
#define MCR 4 /* Modem control */
|
|
#define LSR 5 /* Line Status */
|
|
#define MSR 6 /* Modem Status */
|
|
#define DLL 0 /* Divisor Latch Low */
|
|
#define DLH 1 /* Divisor latch High */
|
|
|
|
#define DEFAULT_BAUD 9600
|
|
|
|
static void early_serial_init(int port, int baud)
|
|
{
|
|
unsigned char c;
|
|
unsigned divisor;
|
|
|
|
outb(0x3, port + LCR); /* 8n1 */
|
|
outb(0, port + IER); /* no interrupt */
|
|
outb(0, port + FCR); /* no fifo */
|
|
outb(0x3, port + MCR); /* DTR + RTS */
|
|
|
|
divisor = 115200 / baud;
|
|
c = inb(port + LCR);
|
|
outb(c | DLAB, port + LCR);
|
|
outb(divisor & 0xff, port + DLL);
|
|
outb((divisor >> 8) & 0xff, port + DLH);
|
|
outb(c & ~DLAB, port + LCR);
|
|
|
|
early_serial_base = port;
|
|
}
|
|
|
|
static void parse_earlyprintk(void)
|
|
{
|
|
int baud = DEFAULT_BAUD;
|
|
char arg[32];
|
|
int pos = 0;
|
|
int port = 0;
|
|
|
|
if (cmdline_find_option("earlyprintk", arg, sizeof arg) > 0) {
|
|
char *e;
|
|
|
|
if (!strncmp(arg, "serial", 6)) {
|
|
port = DEFAULT_SERIAL_PORT;
|
|
pos += 6;
|
|
}
|
|
|
|
if (arg[pos] == ',')
|
|
pos++;
|
|
|
|
/*
|
|
* make sure we have
|
|
* "serial,0x3f8,115200"
|
|
* "serial,ttyS0,115200"
|
|
* "ttyS0,115200"
|
|
*/
|
|
if (pos == 7 && !strncmp(arg + pos, "0x", 2)) {
|
|
port = simple_strtoull(arg + pos, &e, 16);
|
|
if (port == 0 || arg + pos == e)
|
|
port = DEFAULT_SERIAL_PORT;
|
|
else
|
|
pos = e - arg;
|
|
} else if (!strncmp(arg + pos, "ttyS", 4)) {
|
|
static const int bases[] = { 0x3f8, 0x2f8 };
|
|
int idx = 0;
|
|
|
|
if (!strncmp(arg + pos, "ttyS", 4))
|
|
pos += 4;
|
|
|
|
if (arg[pos++] == '1')
|
|
idx = 1;
|
|
|
|
port = bases[idx];
|
|
}
|
|
|
|
if (arg[pos] == ',')
|
|
pos++;
|
|
|
|
baud = simple_strtoull(arg + pos, &e, 0);
|
|
if (baud == 0 || arg + pos == e)
|
|
baud = DEFAULT_BAUD;
|
|
}
|
|
|
|
if (port)
|
|
early_serial_init(port, 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 void parse_console_uart8250(void)
|
|
{
|
|
char optstr[64], *options;
|
|
int baud = DEFAULT_BAUD;
|
|
int port = 0;
|
|
|
|
/*
|
|
* console=uart8250,io,0x3f8,115200n8
|
|
* need to make sure it is last one console !
|
|
*/
|
|
if (cmdline_find_option("console", optstr, sizeof optstr) <= 0)
|
|
return;
|
|
|
|
options = optstr;
|
|
|
|
if (!strncmp(options, "uart8250,io,", 12))
|
|
port = simple_strtoull(options + 12, &options, 0);
|
|
else if (!strncmp(options, "uart,io,", 8))
|
|
port = simple_strtoull(options + 8, &options, 0);
|
|
else
|
|
return;
|
|
|
|
if (options && (options[0] == ','))
|
|
baud = simple_strtoull(options + 1, &options, 0);
|
|
else
|
|
baud = probe_baud(port);
|
|
|
|
if (port)
|
|
early_serial_init(port, baud);
|
|
}
|
|
|
|
void console_init(void)
|
|
{
|
|
parse_earlyprintk();
|
|
|
|
if (!early_serial_base)
|
|
parse_console_uart8250();
|
|
}
|