1/* early printk support 2 * 3 * Copyright (c) 2009 Philippe Vachon <philippe@cowpig.ca> 4 * Copyright (c) 2009 Lemote Inc. 5 * Author: Wu Zhangjin, wuzhangjin@gmail.com 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by the 9 * Free Software Foundation; either version 2 of the License, or (at your 10 * option) any later version. 11 */ 12#include <linux/serial_reg.h> 13 14#include <loongson.h> 15 16#define PORT(base, offset) (u8 *)(base + offset) 17 18static inline unsigned int serial_in(unsigned char *base, int offset) 19{ 20 return readb(PORT(base, offset)); 21} 22 23static inline void serial_out(unsigned char *base, int offset, int value) 24{ 25 writeb(value, PORT(base, offset)); 26} 27 28void prom_putchar(char c) 29{ 30 int timeout; 31 unsigned char *uart_base; 32 33 uart_base = (unsigned char *)_loongson_uart_base[0]; 34 timeout = 1024; 35 36 while (((serial_in(uart_base, UART_LSR) & UART_LSR_THRE) == 0) && 37 (timeout-- > 0)) 38 ; 39 40 serial_out(uart_base, UART_TX, c); 41} 42