1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/kernel/early_printk.c
4 *
5 * Copyright (C) 2009 Sascha Hauer <s.hauer@pengutronix.de>
6 */
7
8#include <linux/kernel.h>
9#include <linux/console.h>
10#include <linux/init.h>
11#include <linux/string.h>
12
13extern void printascii(const char *);
14
15static void early_write(const char *s, unsigned n)
16{
17 char buf[128];
18 while (n) {
19 unsigned l = min(n, sizeof(buf)-1);
20 memcpy(buf, s, l);
21 buf[l] = 0;
22 s += l;
23 n -= l;
24 printascii(buf);
25 }
26}
27
28static void early_console_write(struct console *con, const char *s, unsigned n)
29{
30 early_write(s, n);
31}
32
33static struct console early_console_dev = {
34 .name = "earlycon",
35 .write = early_console_write,
36 .flags = CON_PRINTBUFFER | CON_BOOT,
37 .index = -1,
38};
39
40static int __init setup_early_printk(char *buf)
41{
42 early_console = &early_console_dev;
43 register_console(&early_console_dev);
44 return 0;
45}
46
47early_param("earlyprintk", setup_early_printk);
48

source code of linux/arch/arm/kernel/early_printk.c