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 #include <asm/setup.h>
14
15 #include <loongson.h>
16
17 #define PORT(base, offset) (u8 *)(base + offset)
18
serial_in(unsigned char * base,int offset)19 static inline unsigned int serial_in(unsigned char *base, int offset)
20 {
21 return readb(PORT(base, offset));
22 }
23
serial_out(unsigned char * base,int offset,int value)24 static inline void serial_out(unsigned char *base, int offset, int value)
25 {
26 writeb(value, PORT(base, offset));
27 }
28
prom_putchar(char c)29 void prom_putchar(char c)
30 {
31 int timeout;
32 unsigned char *uart_base;
33
34 uart_base = (unsigned char *)_loongson_uart_base[0];
35 timeout = 1024;
36
37 while (((serial_in(uart_base, UART_LSR) & UART_LSR_THRE) == 0) &&
38 (timeout-- > 0))
39 ;
40
41 serial_out(uart_base, UART_TX, c);
42 }
43
