Catalin Marinas | 93fd03a | 2009-12-09 10:02:18 +0000 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/arm/kernel/early_printk.c |
| 3 | * |
| 4 | * Copyright (C) 2009 Sascha Hauer <s.hauer@pengutronix.de> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | */ |
| 10 | |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/console.h> |
| 13 | #include <linux/init.h> |
| 14 | |
| 15 | extern void printch(int); |
| 16 | |
| 17 | static void early_write(const char *s, unsigned n) |
| 18 | { |
| 19 | while (n-- > 0) { |
| 20 | if (*s == '\n') |
| 21 | printch('\r'); |
| 22 | printch(*s); |
| 23 | s++; |
| 24 | } |
| 25 | } |
| 26 | |
| 27 | static void early_console_write(struct console *con, const char *s, unsigned n) |
| 28 | { |
| 29 | early_write(s, n); |
| 30 | } |
| 31 | |
| 32 | static struct console early_console = { |
| 33 | .name = "earlycon", |
| 34 | .write = early_console_write, |
| 35 | .flags = CON_PRINTBUFFER | CON_BOOT, |
| 36 | .index = -1, |
| 37 | }; |
| 38 | |
| 39 | asmlinkage void early_printk(const char *fmt, ...) |
| 40 | { |
| 41 | char buf[512]; |
| 42 | int n; |
| 43 | va_list ap; |
| 44 | |
| 45 | va_start(ap, fmt); |
| 46 | n = vscnprintf(buf, sizeof(buf), fmt, ap); |
| 47 | early_write(buf, n); |
| 48 | va_end(ap); |
| 49 | } |
| 50 | |
| 51 | static int __init setup_early_printk(char *buf) |
| 52 | { |
| 53 | register_console(&early_console); |
| 54 | return 0; |
| 55 | } |
| 56 | |
| 57 | early_param("earlyprintk", setup_early_printk); |