MIPS: ralink: adds early_printk support
[deliverable/linux.git] / arch / mips / ralink / early_printk.c
CommitLineData
5fff610b
JC
1/*
2 * This program is free software; you can redistribute it and/or modify it
3 * under the terms of the GNU General Public License version 2 as published
4 * by the Free Software Foundation.
5 *
6 * Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
7 */
8
9#include <linux/io.h>
10#include <linux/serial_reg.h>
11
12#include <asm/addrspace.h>
13
14#define EARLY_UART_BASE 0x10000c00
15
16#define UART_REG_RX 0x00
17#define UART_REG_TX 0x04
18#define UART_REG_IER 0x08
19#define UART_REG_IIR 0x0c
20#define UART_REG_FCR 0x10
21#define UART_REG_LCR 0x14
22#define UART_REG_MCR 0x18
23#define UART_REG_LSR 0x1c
24
25static __iomem void *uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE);
26
27static inline void uart_w32(u32 val, unsigned reg)
28{
29 __raw_writel(val, uart_membase + reg);
30}
31
32static inline u32 uart_r32(unsigned reg)
33{
34 return __raw_readl(uart_membase + reg);
35}
36
37void prom_putchar(unsigned char ch)
38{
39 while ((uart_r32(UART_REG_LSR) & UART_LSR_THRE) == 0)
40 ;
41 uart_w32(ch, UART_REG_TX);
42 while ((uart_r32(UART_REG_LSR) & UART_LSR_THRE) == 0)
43 ;
44}
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