osd-contiki/cpu/cc2538/dev/watchdog.c
George Oikonomou d28eb023ef Remove CC2530 and CC2538 dummy watchdog_stop()
The CC2538 the WDT cannot be stopped once it has been started.
The CC2530/1 WDT can be stopped if it is running in timer mode,
but it cannot be stopped once it has been started in watchdog mode.

Both platforms currently provide "dummy" implementations of `watchdog_stop()`,
one does nothing and the other one basically re-maps `_stop()` to
`_periodic()`.

This was originally done in order to provide implementations for all prototypes
declared in `core/dev/watchdog.h`. In hindsight and as per the discussion
in #1088, this is bad practice since, if the build succeeds, the caller will
expect that the WDT has in fact been stopped, when in reality it has not.

Since the feature (stopping the WDT) is unsupported by the hardware, this pull
removes those dummy implementations. Thus, we will now be able to reliably
detect - at build time - attempts at using this unsupported feature.
2015-06-01 15:24:14 +01:00

110 lines
3.7 KiB
C

/*
* 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);
}
/**
* @}
* @}
*/