blob: c16ebbe5d8e71f340b44d0da8a87a42dfdd4d52e [file] [log] [blame]
#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <asm/io.h>
#include <asm/proto.h>
/* Simple VGA output */
#define VGABASE 0xffffffff800b8000UL
#define MAX_YPOS 25
#define MAX_XPOS 80
static int current_ypos = 1, current_xpos = 0;
static void early_vga_write(struct console *con, const char *str, unsigned n)
{
char c;
int i, k, j;
while ((c = *str++) != '\0' && n-- > 0) {
if (current_ypos >= MAX_YPOS) {
/* scroll 1 line up */
for(k = 1, j = 0; k < MAX_YPOS; k++, j++) {
for(i = 0; i < MAX_XPOS; i++) {
writew(readw(VGABASE + 2*(MAX_XPOS*k + i)),
VGABASE + 2*(MAX_XPOS*j + i));
}
}
for(i = 0; i < MAX_XPOS; i++) {
writew(0x720, VGABASE + 2*(MAX_XPOS*j + i));
}
current_ypos = MAX_YPOS-1;
}
if (c == '\n') {
current_xpos = 0;
current_ypos++;
} else if (c != '\r') {
writew(((0x7 << 8) | (unsigned short) c),
VGABASE + 2*(MAX_XPOS*current_ypos + current_xpos++));
if (current_xpos >= MAX_XPOS) {
current_xpos = 0;
current_ypos++;
}
}
}
}
static struct console early_vga_console = {
name: "earlyvga",
write: early_vga_write,
flags: CON_PRINTBUFFER,
index: -1,
};
/* Serial functions losely based on a similar package from Klaus P. Gerlicher */
int early_serial_base = 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 */
static int early_serial_putc(unsigned char ch)
{
unsigned timeout = 0xffff;
while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
rep_nop();
outb(ch, early_serial_base + TXR);
return timeout ? 0 : -1;
}
static void early_serial_write(struct console *con, const char *s, unsigned n)
{
while (*s && n-- > 0) {
early_serial_putc(*s);
if (*s == '\n')
early_serial_putc('\r');
s++;
}
}
static __init void early_serial_init(char *opt)
{
unsigned char c;
unsigned divisor, baud = 38400;
char *s, *e;
if (*opt == ',')
++opt;
s = strsep(&opt, ",");
if (s != NULL) {
unsigned port;
if (!strncmp(s,"0x",2))
early_serial_base = simple_strtoul(s, &e, 16);
else {
static int bases[] = { 0x3f8, 0x2f8 };
if (!strncmp(s,"ttyS",4))
s+=4;
port = simple_strtoul(s, &e, 10);
if (port > 1 || s == e)
port = 0;
early_serial_base = bases[port];
}
}
outb(0x3, early_serial_base + LCR); /* 8n1 */
outb(0, early_serial_base + IER); /* no interrupt */
outb(0, early_serial_base + FCR); /* no fifo */
outb(0x3, early_serial_base + MCR); /* DTR + RTS */
s = strsep(&opt, ",");
if (s != NULL) {
baud = simple_strtoul(s, &e, 0);
if (baud == 0 || s == e)
baud = 38400;
}
divisor = 115200 / baud;
c = inb(early_serial_base + LCR);
outb(c | DLAB, early_serial_base + LCR);
outb(divisor & 0xff, early_serial_base + DLL);
outb((divisor >> 8) & 0xff, early_serial_base + DLH);
outb(c & ~DLAB, early_serial_base + LCR);
}
static struct console early_serial_console = {
name: "earlyser",
write: early_serial_write,
flags: CON_PRINTBUFFER,
index: -1,
};
/* Direct interface for emergencies */
struct console *early_console = &early_vga_console;
static int early_console_initialized = 0;
void early_printk(const char *fmt, ...)
{
char buf[512];
int n;
va_list ap;
va_start(ap,fmt);
n = vsnprintf(buf,512,fmt,ap);
early_console->write(early_console,buf,n);
va_end(ap);
}
static int keep_early;
int __init setup_early_printk(char *opt)
{
char *space;
char buf[256];
if (early_console_initialized)
return -1;
strncpy(buf,opt,256);
buf[255] = 0;
space = strchr(buf, ' ');
if (space)
*space = 0;
if (strstr(buf,"keep"))
keep_early = 1;
if (!strncmp(buf, "serial", 6)) {
early_serial_init(buf + 6);
early_console = &early_serial_console;
} else if (!strncmp(buf, "vga", 3)) {
early_console = &early_vga_console;
} else {
early_console = NULL;
return -1;
}
early_console_initialized = 1;
register_console(early_console);
return 0;
}
void __init disable_early_printk(void)
{
if (!early_console_initialized || !early_console)
return;
if (!keep_early) {
printk("Disabling early console\n");
unregister_console(early_console);
early_console_initialized = 0;
}
}
/* syntax: earlyprintk=vga
earlyprintk=serial[,ttySn[,baudrate]]
Append ,keep to not disable it when the real console takes over.
Only vga or serial at a time, not both.
Currently only ttyS0 and ttyS1 are supported.
Interaction with the standard serial driver is not very good.
The VGA output is eventually overwritten by the real console. */
__setup("earlyprintk=", setup_early_printk);