reset.c
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/*
* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/pm.h>
#include <asm/reboot.h>
#include <asm/mach-jz4740/base.h>
#include <asm/mach-jz4740/timer.h>
#include "reset.h"
#include "clock.h"
static void jz4740_halt(void)
{
while (1) {
__asm__(".set push;\n"
".set mips3;\n"
"wait;\n"
".set pop;\n"
);
}
}
#define JZ_REG_WDT_DATA 0x00
#define JZ_REG_WDT_COUNTER_ENABLE 0x04
#define JZ_REG_WDT_COUNTER 0x08
#define JZ_REG_WDT_CTRL 0x0c
static void jz4740_restart(char *command)
{
void __iomem *wdt_base = ioremap(JZ4740_WDT_BASE_ADDR, 0x0f);
jz4740_timer_enable_watchdog();
writeb(0, wdt_base + JZ_REG_WDT_COUNTER_ENABLE);
writew(0, wdt_base + JZ_REG_WDT_COUNTER);
writew(0, wdt_base + JZ_REG_WDT_DATA);
writew(BIT(2), wdt_base + JZ_REG_WDT_CTRL);
writeb(1, wdt_base + JZ_REG_WDT_COUNTER_ENABLE);
jz4740_halt();
}
#define JZ_REG_RTC_CTRL 0x00
#define JZ_REG_RTC_HIBERNATE 0x20
#define JZ_REG_RTC_WAKEUP_FILTER 0x24
#define JZ_REG_RTC_RESET_COUNTER 0x28
#define JZ_RTC_CTRL_WRDY BIT(7)
#define JZ_RTC_WAKEUP_FILTER_MASK 0x0000FFE0
#define JZ_RTC_RESET_COUNTER_MASK 0x00000FE0
static inline void jz4740_rtc_wait_ready(void __iomem *rtc_base)
{
uint32_t ctrl;
do {
ctrl = readl(rtc_base + JZ_REG_RTC_CTRL);
} while (!(ctrl & JZ_RTC_CTRL_WRDY));
}
static void jz4740_power_off(void)
{
void __iomem *rtc_base = ioremap(JZ4740_RTC_BASE_ADDR, 0x38);
unsigned long wakeup_filter_ticks;
unsigned long reset_counter_ticks;
struct clk *rtc_clk;
unsigned long rtc_rate;
rtc_clk = clk_get(NULL, "rtc");
if (IS_ERR(rtc_clk))
panic("unable to get RTC clock");
rtc_rate = clk_get_rate(rtc_clk);
clk_put(rtc_clk);
/*
* Set minimum wakeup pin assertion time: 100 ms.
* Range is 0 to 2 sec if RTC is clocked at 32 kHz.
*/
wakeup_filter_ticks = (100 * rtc_rate) / 1000;
if (wakeup_filter_ticks < JZ_RTC_WAKEUP_FILTER_MASK)
wakeup_filter_ticks &= JZ_RTC_WAKEUP_FILTER_MASK;
else
wakeup_filter_ticks = JZ_RTC_WAKEUP_FILTER_MASK;
jz4740_rtc_wait_ready(rtc_base);
writel(wakeup_filter_ticks, rtc_base + JZ_REG_RTC_WAKEUP_FILTER);
/*
* Set reset pin low-level assertion time after wakeup: 60 ms.
* Range is 0 to 125 ms if RTC is clocked at 32 kHz.
*/
reset_counter_ticks = (60 * rtc_rate) / 1000;
if (reset_counter_ticks < JZ_RTC_RESET_COUNTER_MASK)
reset_counter_ticks &= JZ_RTC_RESET_COUNTER_MASK;
else
reset_counter_ticks = JZ_RTC_RESET_COUNTER_MASK;
jz4740_rtc_wait_ready(rtc_base);
writel(reset_counter_ticks, rtc_base + JZ_REG_RTC_RESET_COUNTER);
jz4740_rtc_wait_ready(rtc_base);
writel(1, rtc_base + JZ_REG_RTC_HIBERNATE);
jz4740_halt();
}
void jz4740_reset_init(void)
{
_machine_restart = jz4740_restart;
_machine_halt = jz4740_halt;
pm_power_off = jz4740_power_off;
}