flight/pios/inc/pios_semaphore.h

   1 /**
   2  ******************************************************************************
   3  * @file       pios_semaphore.h
   4  * @author     Tau Labs, http://taulabs.org, Copyright (C) 2013-2014
   5  * @addtogroup PIOS PIOS Core hardware abstraction layer
   6  * @{
   7  * @addtogroup PIOS_Semaphore Semaphore Abstraction
   8  * @{
   9  * @brief Abstracts the concept of a binary semaphore to hide different implementations
  10  *****************************************************************************/
  11 /*
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 3 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  20  * for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License along
  23  * with this program; if not, write to the Free Software Foundation, Inc.,
  24  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  25  */
  26
  27
  28 #ifndef PIOS_SEMAPHORE_H_
  29 #define PIOS_SEMAPHORE_H_
  30
  31 #define PIOS_SEMAPHORE_TIMEOUT_MAX 0xffffffff
  32
  33 #include <stdint.h>
  34 #include <stdbool.h>
  35
  36 struct pios_semaphore {
  37 #if defined(PIOS_INCLUDE_FREERTOS)
  38     uintptr_t sema_handle;
  39 #elif defined(PIOS_INCLUDE_CHIBIOS)
  40     BinarySemaphore sema;
  41 #elif defined(PIOS_INCLUDE_IRQ)
  42     uint32_t sema_count;
  43 #endif /* defined(PIOS_INCLUDE_IRQ) */
  44 };
  45
  46 /*
  47  * The following functions implement the concept of a binary semaphore usable
  48  * with PIOS_INCLUDE_FREERTOS, PIOS_INCLUDE_CHIBIOS or PIOS_INCLUDE_IRQ.
  49  *
  50  * Note that this is not the same as:
  51  * - counting semaphore
  52  * - mutex
  53  * - recursive mutex
  54  *
  55  * see FreeRTOS documentation for details: http://www.freertos.org/a00113.html
  56  * see ChibiOS documentation for details: http://chibios.sourceforge.net/html/group__synchronization.html
  57  */
  58
  59 struct pios_semaphore *PIOS_Semaphore_Create(void);
  60 bool PIOS_Semaphore_Take(struct pios_semaphore *sema, uint32_t timeout_ms);
  61 bool PIOS_Semaphore_Give(struct pios_semaphore *sema);
  62
  63 bool PIOS_Semaphore_Take_FromISR(struct pios_semaphore *sema, bool *woken);
  64 bool PIOS_Semaphore_Give_FromISR(struct pios_semaphore *sema, bool *woken);
  65
  66 #endif /* PIOS_SEMAPHORE_H_ */
  67
  68 /**
  69  * @}
  70  * @}
  71  */