linux/arch/mips/ath79/early_printk.c

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/*
* Atheros AR7XXX/AR9XXX SoC early printk support
*
* Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
*
* 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.
*/
#include <linux/io.h>
#include <linux/errno.h>
#include <linux/serial_reg.h>
#include <asm/addrspace.h>
#include <asm/mach-ath79/ath79.h>
#include <asm/mach-ath79/ar71xx_regs.h>
#include <asm/mach-ath79/ar933x_uart.h>
static void (*_prom_putchar) (unsigned char);
static inline void prom_putchar_wait(void __iomem *reg, u32 mask, u32 val)
{
u32 t;
do {
t = __raw_readl(reg);
if ((t & mask) == val)
break;
} while (1);
}
static void prom_putchar_ar71xx(unsigned char ch)
{
void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));
prom_putchar_wait(base + UART_LSR * 4, UART_LSR_THRE, UART_LSR_THRE);
__raw_writel(ch, base + UART_TX * 4);
prom_putchar_wait(base + UART_LSR * 4, UART_LSR_THRE, UART_LSR_THRE);
}
static void prom_putchar_ar933x(unsigned char ch)
{
void __iomem *base = (void __iomem *)(KSEG1ADDR(AR933X_UART_BASE));
prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR,
AR933X_UART_DATA_TX_CSR);
__raw_writel(AR933X_UART_DATA_TX_CSR | ch, base + AR933X_UART_DATA_REG);
prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR,
AR933X_UART_DATA_TX_CSR);
}
static void prom_putchar_dummy(unsigned char ch)
{
/* nothing to do */
}
static void prom_putchar_init(void)
{
void __iomem *base;
u32 id;
base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE));
id = __raw_readl(base + AR71XX_RESET_REG_REV_ID);
id &= REV_ID_MAJOR_MASK;
switch (id) {
case REV_ID_MAJOR_AR71XX:
case REV_ID_MAJOR_AR7240:
case REV_ID_MAJOR_AR7241:
case REV_ID_MAJOR_AR7242:
case REV_ID_MAJOR_AR913X:
case REV_ID_MAJOR_AR9341:
case REV_ID_MAJOR_AR9342:
case REV_ID_MAJOR_AR9344:
_prom_putchar = prom_putchar_ar71xx;
break;
case REV_ID_MAJOR_AR9330:
case REV_ID_MAJOR_AR9331:
_prom_putchar = prom_putchar_ar933x;
break;
default:
_prom_putchar = prom_putchar_dummy;
break;
}
}
void prom_putchar(unsigned char ch)
{
if (!_prom_putchar)
prom_putchar_init();
_prom_putchar(ch);
}