#include <linux/console.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/string.h> #include <asm/io.h> #include <asm/processor.h> /* Simple VGA output */ #ifdef __i386__ #define VGABASE __pa((void *)(__PAGE_OFFSET + 0xb8000UL)) #else #define VGABASE 0xffffffff800b8000UL #endif #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 loosely 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) cpu_relax(); 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++; } } #define DEFAULT_BAUD 9600 static __init void early_serial_init(char *s) { unsigned char c; unsigned divisor; unsigned baud = DEFAULT_BAUD; char *e; if (*s == ',') ++s; if (*s) { 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]; } s += strcspn(s, ","); if (*s == ',') s++; } 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 */ if (*s) { baud = simple_strtoul(s, &e, 0); if (baud == 0 || s == e) baud = DEFAULT_BAUD; } 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 = vscnprintf(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; opt = strchr(opt, '=') + 1; strlcpy(buf,opt,sizeof(buf)); 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, "ttyS", 4)) { early_serial_init(buf); 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; } else { printk("keeping early console\n"); } } __setup("earlyprintk=", setup_early_printk);