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LibrePilot/flight/pios/stm32f0x/pios_irq.c

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/**
******************************************************************************
* @addtogroup PIOS PIOS Core hardware abstraction layer
* @{
* @addtogroup PIOS_IRQ IRQ Setup Functions
* @brief STM32 Hardware code to enable and disable interrupts
* @{
*
* @file pios_irq.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* Parts by Thorsten Klose (tk@midibox.org) (tk@midibox.org)
* @brief IRQ Enable/Disable routines
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* 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"
#ifdef PIOS_INCLUDE_IRQ
/* Private Function Prototypes */
/* Local Variables */
/* The nesting counter ensures, that interrupts won't be enabled so long nested functions disable them */
static uint32_t nested_ctr;
/* Stored priority level before IRQ has been disabled (important for co-existence with vPortEnterCritical) */
static uint32_t prev_primask;
/**
* Disables all interrupts (nested)
* \return < 0 On errors
*/
int32_t PIOS_IRQ_Disable(void)
{
/* Get current priority if nested level == 0 */
if (!nested_ctr) {
__asm volatile (" mrs %0, primask\n" : "=r" (prev_primask)
);
}
/* Disable interrupts */
__asm volatile (" mov r0, #1 \n" " msr primask, r0\n" ::: "r0");
++nested_ctr;
/* No error */
return 0;
}
/**
* Enables all interrupts (nested)
* \return < 0 on errors
* \return -1 on nesting errors (PIOS_IRQ_Disable() hasn't been called before)
*/
int32_t PIOS_IRQ_Enable(void)
{
/* Check for nesting error */
if (nested_ctr == 0) {
/* Nesting error */
return -1;
}
/* Decrease nesting level */
--nested_ctr;
/* Set back previous priority once nested level reached 0 again */
if (nested_ctr == 0) {
__asm volatile (" msr primask, %0\n" ::"r" (prev_primask)
);
}
/* No error */
return 0;
}
#endif /* PIOS_INCLUDE_IRQ */
/**
* @}
* @}
*/