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/* Copyright (c) 2012 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 <stdint.h>
#include "board.h"
#include "common.h"
#include "config.h"
#include "registers.h"
#include "gpio.h"
#include "task.h"
#include "timer.h"
#include "uart.h"
#include "util.h"
/* LSI oscillator frequency is typically 38 kHz
* but might vary from 28 to 56kHz.
* So let's pick 56kHz to ensure we reload
* early enough.
*/
#define LSI_CLOCK 56000
/* Prescaler divider = /256 */
#define IWDG_PRESCALER 6
#define IWDG_PRESCALER_DIV (1 << ((IWDG_PRESCALER) + 2))
void watchdog_reload(void)
{
/* Reload the watchdog */
STM32L_IWDG_KR = 0xaaaa;
}
int watchdog_init(int period_ms)
{
uint32_t watchdog_period;
/* set the time-out period */
watchdog_period = period_ms * (LSI_CLOCK / IWDG_PRESCALER_DIV) / 1000;
/* Unlock watchdog registers */
STM32L_IWDG_KR = 0x5555;
/* Set the prescaler between the LSI clock and the watchdog counter */
STM32L_IWDG_PR = IWDG_PRESCALER & 7;
/* Set the reload value of the watchdog counter */
STM32L_IWDG_RLR = watchdog_period & 0x7FF ;
/* Start the watchdog (and re-lock registers) */
STM32L_IWDG_KR = 0xcccc;
return EC_SUCCESS;
}
/* Low priority task to reload the watchdog */
void watchdog_task(void)
{
while (1) {
#ifdef BOARD_discovery
gpio_set_level(GPIO_GREEN_LED, 1);
#endif
usleep(500000);
watchdog_reload();
#ifdef BOARD_discovery
gpio_set_level(GPIO_GREEN_LED, 0);
#endif
usleep(500000);
watchdog_reload();
}
}
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