osd-contiki/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"
/*---------------------------------------------------------------------------*/
/** \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, maximum interval */
void
watchdog_start(void)
{
/* Max interval (32768), watchdog mode, Enable */
REG(SMWDTHROSC_WDCTL) = SMWDTHROSC_WDCTL_EN;
}
/*---------------------------------------------------------------------------*/
/** \brief Writes the WDT clear sequence. This function assumes that we are
* in watchdog mode and that interval bits (bits [1:0]) are 00 */
void
watchdog_periodic(void)
{
/* Safe to write to bits [3:0] since EN is 1 */
REG(SMWDTHROSC_WDCTL) = (SMWDTHROSC_WDCTL_CLR_3 | SMWDTHROSC_WDCTL_CLR_1);
REG(SMWDTHROSC_WDCTL) = (SMWDTHROSC_WDCTL_CLR_2 | SMWDTHROSC_WDCTL_CLR_0);
}
/*---------------------------------------------------------------------------*/
/** \brief In watchdog mode, the WDT can not be stopped. This function is
* defined here to satisfy API requirements.
*/
void
watchdog_stop(void)
{
return;
}
/*---------------------------------------------------------------------------*/
/** \brief Keeps control until the WDT throws a reset signal */
void
watchdog_reboot(void)
{
INTERRUPTS_DISABLE();
watchdog_start(); /* just in case the WDT hasn't been started yet */
while(1);
}
/**
* @}
* @}
*/