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LibrePilot/flight/pios/stm32f10x/pios_wdg.c

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/**
******************************************************************************
* @addtogroup PIOS PIOS Core hardware abstraction layer
* @{
* @addtogroup PIOS_WDG Watchdog Functions
* @brief PIOS Comamnds to initialize and clear watchdog timer
* @{
*
* @file pios_spi.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* Parts by Thorsten Klose (tk@midibox.org) (tk@midibox.org)
* @brief Hardware Abstraction Layer for SPI ports of STM32
* @see The GNU Public License (GPL) Version 3
* @notes
*
* The PIOS Watchdog provides a HAL to initialize a watchdog
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "pios.h"
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#ifdef PIOS_INCLUDE_WDG
#include "stm32f10x_iwdg.h"
#include "stm32f10x_dbgmcu.h"
static struct wdg_configuration {
uint16_t used_flags;
uint16_t bootup_flags;
} wdg_configuration;
/**
* @brief Initialize the watchdog timer for a specified timeout
*
* It is important to note that this function returns the achieved timeout
* for this hardware. For hardware indendence this should be checked when
* scheduling updates. Other hardware dependent details may need to be
* considered such as a window time which sets a minimum update time,
* and this function should return a recommended delay for clearing.
*
* For the STM32 nominal clock rate is 32 khz, but for the maximum clock rate of
* 60 khz and a prescalar of 4 yields a clock rate of 15 khz. The delay that is
* set in the watchdog assumes the nominal clock rate, but the delay for FreeRTOS
* to use is 75% of the minimal delay.
*
* @returns Maximum recommended delay between updates based on PIOS_WATCHDOG_TIMEOUT constant
*/
uint16_t PIOS_WDG_Init()
{
uint16_t delay = ((uint32_t)PIOS_WATCHDOG_TIMEOUT * 60) / 16;
if (delay > 0x0fff) {
delay = 0x0fff;
}
#if defined(PIOS_INCLUDE_WDG)
DBGMCU_Config(DBGMCU_IWDG_STOP, ENABLE); // make the watchdog stop counting in debug mode
IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
IWDG_SetPrescaler(IWDG_Prescaler_16);
IWDG_SetReload(delay);
IWDG_ReloadCounter();
IWDG_Enable();
// watchdog flags now stored in backup registers
PWR_BackupAccessCmd(ENABLE);
BKP_WriteBackupRegister(PIOS_WDG_REGISTER, 0x0);
wdg_configuration.bootup_flags = BKP_ReadBackupRegister(PIOS_WDG_REGISTER);
#endif
return delay;
}
/**
* @brief Register a module against the watchdog
*
* There are two ways to use PIOS WDG: this is for when
* multiple modules must be monitored. In this case they
* must first register against the watchdog system and
* only when all of the modules have been updated with the
* watchdog be cleared. Each module must have its own
* bit in the 16 bit
*
* @param[in] flag the bit this module wants to use
* @returns True if that bit is unregistered
*/
bool PIOS_WDG_RegisterFlag(uint16_t flag_requested)
{
// flag are being registered so we are in module initialization phase
// clear the WDG to prevent timeout while initializing modules. (OP-815)
PIOS_WDG_Clear();
/* Fail if flag already registered */
if (wdg_configuration.used_flags & flag_requested) {
return false;
}
// FIXME: Protect with semaphore
wdg_configuration.used_flags |= flag_requested;
return true;
}
/**
* @brief Function called by modules to indicate they are still running
*
* This function will set this flag in the active flags register (which is
* a backup regsiter) and if all the registered flags are set will clear
* the watchdog and set only this flag in the backup register
*
* @param[in] flag the flag to set
* @return true if the watchdog cleared, false if flags are pending
*/
bool PIOS_WDG_UpdateFlag(uint16_t flag)
{
// we can probably avoid using a semaphore here which will be good for
// efficiency and not blocking critical tasks. race condition could
// overwrite their flag update, but unlikely to block _all_ of them
// for the timeout window
uint16_t cur_flags = BKP_ReadBackupRegister(PIOS_WDG_REGISTER);
if ((cur_flags | flag) == wdg_configuration.used_flags) {
PIOS_WDG_Clear();
BKP_WriteBackupRegister(PIOS_WDG_REGISTER, flag);
return true;
} else {
BKP_WriteBackupRegister(PIOS_WDG_REGISTER, cur_flags | flag);
return false;
}
}
/**
* @brief Returns the flags that were set at bootup
*
* This is used for diagnostics, if only one flag not set this
* was likely the module that wasn't running before reset
*
* @return The active flags register from bootup
*/
uint16_t PIOS_WDG_GetBootupFlags()
{
return wdg_configuration.bootup_flags;
}
/**
* @brief Returns the currently active flags
*
* For external monitoring
*
* @return The active flags register
*/
uint16_t PIOS_WDG_GetActiveFlags()
{
return BKP_ReadBackupRegister(PIOS_WDG_REGISTER);
}
/**
* @brief Clear the watchdog timer
*
* This function must be called at the appropriate delay to prevent a reset event occuring
*/
void PIOS_WDG_Clear(void)
{
#if defined(PIOS_INCLUDE_WDG)
IWDG_ReloadCounter();
#endif
}
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#endif /* PIOS_INCLUDE_WDG */