nes-proj/cpu/cc2538/dev/watchdog.c

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/*
* Copyright (c) 2012, Texas Instruments Incorporated - http://www.ti.com/
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \addtogroup cc2538
* @{
*
* \defgroup cc2538-wdt cc2538 watchdog timer driver
*
* Driver for the cc2538 Watchdog Timer
* @{
*
* \file
* Implementation of the cc2538 watchdog driver. The peripheral runs in
* watchdog mode.
*/
#include "contiki.h"
#include "reg.h"
#include "cpu.h"
#include "dev/smwdthrosc.h"
/*---------------------------------------------------------------------------*/
/* Enabled by default */
#ifndef WATCHDOG_CONF_ENABLE
#define WATCHDOG_CONF_ENABLE 1
#endif
#if WATCHDOG_CONF_ENABLE
#define WATCHDOG_ENABLE SMWDTHROSC_WDCTL_EN
#else
#define WATCHDOG_ENABLE 0
#endif
/*---------------------------------------------------------------------------*/
/** \brief Initialisation function for the WDT. Currently simply explicitly
* sets the WDT interval to max interval */
void
watchdog_init(void)
{
/* Max interval, don't enable yet */
REG(SMWDTHROSC_WDCTL) = 0;
}
/*---------------------------------------------------------------------------*/
/** \brief Starts the WDT in watchdog mode if enabled by user configuration,
* maximum interval */
void
watchdog_start(void)
{
/* Max interval (32768), watchdog mode, enable if configured to do so */
REG(SMWDTHROSC_WDCTL) = WATCHDOG_ENABLE;
}
/*---------------------------------------------------------------------------*/
/**
* \brief Writes the WDT clear sequence.
*
* Due to how the SMWDTHROSC_WDCTL works, it is OK to simply write these bits
* rather than use RMW operations.
*/
void
watchdog_periodic(void)
{
REG(SMWDTHROSC_WDCTL) = (SMWDTHROSC_WDCTL_CLR_3 | SMWDTHROSC_WDCTL_CLR_1);
REG(SMWDTHROSC_WDCTL) = (SMWDTHROSC_WDCTL_CLR_2 | SMWDTHROSC_WDCTL_CLR_0);
}
/*---------------------------------------------------------------------------*/
/** \brief Keeps control until the WDT throws a reset signal. Starts the WDT
* if not already started. */
void
watchdog_reboot(void)
{
INTERRUPTS_DISABLE();
/*
* If the WDT is not started, set minimum interval and start
* If the WDT is started, this will have no effect
*/
REG(SMWDTHROSC_WDCTL) = SMWDTHROSC_WDCTL_INT | SMWDTHROSC_WDCTL_EN;
while(1);
}
/**
* @}
* @}
*/