/* * linux/arch/arm/kernel/early_printk.c * * Copyright (C) 2009 Sascha Hauer <s.hauer@pengutronix.de> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/kernel.h> #include <linux/console.h> #include <linux/init.h> extern void printch(int); static void early_write(const char *s, unsigned n) { while (n-- > 0) { if (*s == '\n') printch('\r'); printch(*s); s++; } } static void early_console_write(struct console *con, const char *s, unsigned n) { early_write(s, n); } static struct console early_console = { .name = "earlycon", .write = early_console_write, .flags = CON_PRINTBUFFER | CON_BOOT, .index = -1, }; asmlinkage void early_printk(const char *fmt, ...) { char buf[512]; int n; va_list ap; va_start(ap, fmt); n = vscnprintf(buf, sizeof(buf), fmt, ap); early_write(buf, n); va_end(ap); } static int __init setup_early_printk(char *buf) { register_console(&early_console); return 0; } early_param("earlyprintk", setup_early_printk);