/*  early printk support
   *
   *  Copyright (c) 2009 Philippe Vachon <philippe@cowpig.ca>
   *  Copyright (c) 2009 Lemote Inc.
   *  Author: Wu Zhangjin, wuzhangjin@gmail.com
   *
   *  This program is free software; you can redistribute	 it and/or modify it
   *  under  the terms of	 the GNU General  Public License as published by the
   *  Free Software Foundation;  either version 2 of the	License, or (at your
   *  option) any later version.
   */
  #include <linux/serial_reg.h>
  
  #include <loongson.h>
  
  #define PORT(base, offset) (u8 *)(base + offset)
  
  static inline unsigned int serial_in(unsigned char *base, int offset)
  {
  	return readb(PORT(base, offset));
  }
  
  static inline void serial_out(unsigned char *base, int offset, int value)
  {
  	writeb(value, PORT(base, offset));
  }
  
  void prom_putchar(char c)
  {
  	int timeout;
  	unsigned char *uart_base;
  
  	uart_base = (unsigned char *)_loongson_uart_base[0];
  	timeout = 1024;
  
  	while (((serial_in(uart_base, UART_LSR) & UART_LSR_THRE) == 0) &&
  			(timeout-- > 0))
  		;
  
  	serial_out(uart_base, UART_TX, c);
  }