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93fd03a8 CM |
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); |