aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/kernel/early_printk.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/kernel/early_printk.c')
-rw-r--r--arch/arm/kernel/early_printk.c57
1 files changed, 57 insertions, 0 deletions
diff --git a/arch/arm/kernel/early_printk.c b/arch/arm/kernel/early_printk.c
new file mode 100644
index 000000000000..85aa2b292692
--- /dev/null
+++ b/arch/arm/kernel/early_printk.c
@@ -0,0 +1,57 @@
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
15extern void printch(int);
16
17static 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
27static void early_console_write(struct console *con, const char *s, unsigned n)
28{
29 early_write(s, n);
30}
31
32static struct console early_console = {
33 .name = "earlycon",
34 .write = early_console_write,
35 .flags = CON_PRINTBUFFER | CON_BOOT,
36 .index = -1,
37};
38
39asmlinkage 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
51static int __init setup_early_printk(char *buf)
52{
53 register_console(&early_console);
54 return 0;
55}
56
57early_param("earlyprintk", setup_early_printk);