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MIPS: ralink: adds early_printk support 

Add the code needed to make early printk work.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/4897/
This commit is contained in:
John Crispin 2013-01-20 22:02:55 +01:00
parent 3a5bfe7bdb
commit 5fff610b7c
1 changed files with 44 additions and 0 deletions
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44
arch/mips/ralink/early_printk.c Normal file
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/*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
*/
#include <linux/io.h>
#include <linux/serial_reg.h>
#include <asm/addrspace.h>
#define EARLY_UART_BASE 0x10000c00
#define UART_REG_RX 0x00
#define UART_REG_TX 0x04
#define UART_REG_IER 0x08
#define UART_REG_IIR 0x0c
#define UART_REG_FCR 0x10
#define UART_REG_LCR 0x14
#define UART_REG_MCR 0x18
#define UART_REG_LSR 0x1c
static __iomem void *uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE);
static inline void uart_w32(u32 val, unsigned reg)
{
__raw_writel(val, uart_membase + reg);
}
static inline u32 uart_r32(unsigned reg)
{
return __raw_readl(uart_membase + reg);
}
void prom_putchar(unsigned char ch)
{
while ((uart_r32(UART_REG_LSR) & UART_LSR_THRE) == 0)
;
uart_w32(ch, UART_REG_TX);
while ((uart_r32(UART_REG_LSR) & UART_LSR_THRE) == 0)
;
}