flight/pios/stm32f4xx/pios_irq.c

   1 /**
   2  ******************************************************************************
   3  * @addtogroup PIOS PIOS Core hardware abstraction layer
   4  * @{
   5  * @addtogroup PIOS_IRQ IRQ Setup Functions
   6  * @brief STM32 Hardware code to enable and disable interrupts
   7  * @{
   8  *
   9  * @file       pios_irq.c
  10  * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012
  11  * @brief      IRQ Enable/Disable routines
  12  * @see        The GNU Public License (GPL) Version 3
  13  *
  14  *****************************************************************************/
  15 /*
  16  * This program is free software; you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License as published by
  18  * the Free Software Foundation; either version 3 of the License, or
  19  * (at your option) any later version.
  20  *
  21  * This program is distributed in the hope that it will be useful, but
  22  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  23  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  24  * for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License along
  27  * with this program; if not, write to the Free Software Foundation, Inc.,
  28  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  29  */
  30
  31 /*
  32  * @todo This should be shared with the F1xx code.
  33  */
  34
  35 #include "pios.h"
  36
  37 #ifdef PIOS_INCLUDE_IRQ
  38
  39 /* Private Function Prototypes */
  40
  41 /* Local Variables */
  42 /* The nesting counter ensures, that interrupts won't be enabled so long nested functions disable them */
  43 static uint32_t nested_ctr;
  44
  45 /* Stored priority level before IRQ has been disabled (important for co-existence with vPortEnterCritical) */
  46 static uint32_t prev_primask;
  47
  48 /**
  49  * Disables all interrupts (nested)
  50  * \return < 0 On errors
  51  */
  52 int32_t PIOS_IRQ_Disable(void)
  53 {
  54     /* Get current priority if nested level == 0 */
  55     if (!nested_ctr) {
  56         __asm volatile ("   mrs %0, primask\n" : "=r" (prev_primask)
  57                         );
  58     }
  59
  60     /* Disable interrupts */
  61     __asm volatile ("     mov r0, #1     \n" "     msr primask, r0\n" ::: "r0");
  62
  63     ++nested_ctr;
  64
  65     /* No error */
  66     return 0;
  67 }
  68
  69 /**
  70  * Enables all interrupts (nested)
  71  * \return < 0 on errors
  72  * \return -1 on nesting errors (PIOS_IRQ_Disable() hasn't been called before)
  73  */
  74 int32_t PIOS_IRQ_Enable(void)
  75 {
  76     /* Check for nesting error */
  77     if (nested_ctr == 0) {
  78         /* Nesting error */
  79         return -1;
  80     }
  81
  82     /* Decrease nesting level */
  83     --nested_ctr;
  84
  85     /* Set back previous priority once nested level reached 0 again */
  86     if (nested_ctr == 0) {
  87         __asm volatile ("   msr primask, %0\n" ::"r" (prev_primask)
  88                         );
  89     }
  90
  91     /* No error */
  92     return 0;
  93 }
  94
  95 #endif /* PIOS_INCLUDE_IRQ */
  96
  97 /**
  98  * @}
  99  * @}
 100  */