1. 根目录:
2. arch
3. mips
4. mipssim
5. sim_console.c

/*
 *  This program is free software; you can distribute it and/or modify it
 *  under the terms of the GNU General Public License (Version 2) as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Carsten Langgaard, carstenl@mips.com
 * Copyright (C) 1999,2000 MIPS Technologies, Inc.  All rights reserved.
 * Copyright (C) 2007 MIPS Technologies, Inc.
 *   written by Ralf Baechle
 */
#include <linux/init.h>
#include <linux/io.h>
#include <linux/serial_reg.h>

static inline unsigned int serial_in(int offset)
{
	return inb(0x3f8 + offset);
}

static inline void serial_out(int offset, int value)
{
	outb(value, 0x3f8 + offset);
}

void __init prom_putchar(char c)
{
	while ((serial_in(UART_LSR) & UART_LSR_THRE) == 0)
		;

	serial_out(UART_TX, c);
}