early_printk.c (943B)
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);