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/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Watchdog driver */
#include "common.h"
#include "cpu.h"
#include "hooks.h"
#include "hwtimer_chip.h"
#include "panic.h"
#include "registers.h"
#include "task.h"
#include "watchdog.h"
/* Panic data goes at the end of RAM. */
static struct panic_data * const pdata_ptr = PANIC_DATA_PTR;
/* Enter critical period or not. */
static int wdt_warning_fired;
/*
* We use WDT_EXT_TIMER to trigger an interrupt just before the watchdog timer
* will fire so that we can capture important state information before
* being reset.
*/
/* Magic value to tickle the watchdog register. */
#define ITE83XX_WATCHDOG_MAGIC_WORD 0x5C
/* Start to print warning message. */
#define ITE83XX_WATCHDOG_WARNING_MS CONFIG_AUX_TIMER_PERIOD_MS
/* The interval to print warning message at critical period. */
#define ITE83XX_WATCHDOG_CRITICAL_MS 30
/* set warning timer */
static void watchdog_set_warning_timer(int32_t ms, int init)
{
ext_timer_ms(WDT_EXT_TIMER, EXT_PSR_32P768K_HZ, 1, 1, ms, init, 0);
}
void watchdog_warning_irq(void)
{
#ifdef CONFIG_SOFTWARE_PANIC
pdata_ptr->nds_n8.ipc = get_ipc();
#endif
/* clear interrupt status */
task_clear_pending_irq(et_ctrl_regs[WDT_EXT_TIMER].irq);
/* Reset warning timer. */
IT83XX_ETWD_ETXCTRL(WDT_EXT_TIMER) = 0x03;
/*
* The IPC (Interruption Program Counter) is the shadow stack register
* of the PC (Program Counter). It stores the return address of program
* (PC->IPC) when the ISR was called.
*
* The LP (Link Pointer) stores the program address of the next
* sequential instruction for function call return purposes.
* LP = PC+4 after a jump and link instruction (jal).
*/
panic_printf("Pre-WDT warning! IPC:%08x LP:%08x TASK_ID:%d\n",
get_ipc(), ilp, task_get_current());
if (!wdt_warning_fired++)
/*
* Reduce interval of warning timer, so we can print more
* warning messages during critical period.
*/
watchdog_set_warning_timer(ITE83XX_WATCHDOG_CRITICAL_MS, 0);
}
void watchdog_reload(void)
{
/* Reset warning timer. */
IT83XX_ETWD_ETXCTRL(WDT_EXT_TIMER) = 0x03;
/* Restart (tickle) watchdog timer. */
IT83XX_ETWD_EWDKEYR = ITE83XX_WATCHDOG_MAGIC_WORD;
if (wdt_warning_fired) {
wdt_warning_fired = 0;
/* Reset warning timer to default if watchdog is touched. */
watchdog_set_warning_timer(ITE83XX_WATCHDOG_WARNING_MS, 0);
}
}
DECLARE_HOOK(HOOK_TICK, watchdog_reload, HOOK_PRIO_DEFAULT);
int watchdog_init(void)
{
uint16_t wdt_count = CONFIG_WATCHDOG_PERIOD_MS * 1024 / 1000;
/* Unlock access to watchdog registers. */
IT83XX_ETWD_ETWCFG = 0x00;
/* Set WD timer to use 1.024kHz clock. */
IT83XX_ETWD_ET1PSR = 0x01;
/* Set WDT key match enabled and WDT clock to use ET1PSR. */
IT83XX_ETWD_ETWCFG = 0x30;
#ifdef CONFIG_HIBERNATE
/* bit4: watchdog can be stopped. */
IT83XX_ETWD_ETWCTRL |= (1 << 4);
#else
/* Specify that watchdog cannot be stopped. */
IT83XX_ETWD_ETWCTRL = 0x00;
#endif
/* Start WDT_EXT_TIMER (CONFIG_AUX_TIMER_PERIOD_MS ms). */
watchdog_set_warning_timer(ITE83XX_WATCHDOG_WARNING_MS, 1);
/* Start timer 1 (must be started for watchdog timer to run). */
IT83XX_ETWD_ET1CNTLLR = 0x00;
/*
* Set watchdog timer to CONFIG_WATCHDOG_PERIOD_MS ms.
* Writing CNTLL starts timer.
*/
IT83XX_ETWD_EWDCNTLHR = (wdt_count >> 8) & 0xff;
IT83XX_ETWD_EWDCNTLLR = wdt_count & 0xff;
/* Lock access to watchdog registers. */
IT83XX_ETWD_ETWCFG = 0x3f;
return EC_SUCCESS;
}
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