Add mutex API and generic implementation
This commit is contained in:
George Oikonomou
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1b89bba47e
commit
7cd076a199
70
os/sys/mutex.c
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70
os/sys/mutex.c
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/*
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* Copyright (c) 2017, George Oikonomou - http://www.spd.gr
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*---------------------------------------------------------------------------*/
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/**
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* \addtogroup mutex
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* @{
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*/
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/*---------------------------------------------------------------------------*/
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#include "contiki.h"
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#include "sys/mutex.h"
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#include "sys/critical.h"
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#include <stdint.h>
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#include <stdbool.h>
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/*---------------------------------------------------------------------------*/
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bool
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mutex_generic_try_lock(volatile mutex_t *mutex)
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{
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bool success = false;
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int_master_status_t status = critical_enter();
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if(*mutex == MUTEX_STATUS_UNLOCKED) {
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*mutex = MUTEX_STATUS_LOCKED;
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success = true;
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}
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critical_exit(status);
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return success;
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}
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/*---------------------------------------------------------------------------*/
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void
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mutex_generic_unlock(volatile mutex_t *mutex)
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{
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int_master_status_t status = critical_enter();
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*mutex = MUTEX_STATUS_UNLOCKED;
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critical_exit(status);
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}
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/*---------------------------------------------------------------------------*/
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/** @} */
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129
os/sys/mutex.h
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129
os/sys/mutex.h
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/*
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* Copyright (c) 2017, George Oikonomou - http://www.spd.gr
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*---------------------------------------------------------------------------*/
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/**
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* \addtogroup sys
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* @{
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*
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* \defgroup mutex Mutexes
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* @{
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*
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* This library provides an API and generic implementation of mutexes.
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*
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* Calling code should manipulate mutexes through the mutex_try_lock() and
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* mutex_unlock() macros. By default, those macros will expand to the generic
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* mutex manipulation implementations provided here. While these will work,
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* they do reply on disabling the master interrupt in order to perform the
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* lock/unlock operation.
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*
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* It is possible to override those generic implementation with CPU-specific
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* implementations that exploit synchronisation instructions. To do so,
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* create a CPU-specific header file. In this file, define mutex_try_lock()
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* and mutex_unlock() to expand to the respective CPU function names. These
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* can (but do not have to) be inlined. Then define MUTEX_CONF_ARCH_HEADER_PATH
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* as this header's filename.
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*/
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/*---------------------------------------------------------------------------*/
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#ifndef MUTEX_H_
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#define MUTEX_H_
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/*---------------------------------------------------------------------------*/
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#include "contiki.h"
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#include <stdint.h>
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#include <stdbool.h>
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/*---------------------------------------------------------------------------*/
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#define MUTEX_STATUS_LOCKED 1 /** The mutex is locked */
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#define MUTEX_STATUS_UNLOCKED 0 /** The mutex is not locked */
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/*---------------------------------------------------------------------------*/
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#ifdef MUTEX_CONF_ARCH_HEADER_PATH
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#include MUTEX_CONF_ARCH_HEADER_PATH
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#endif /* MUTEX_CONF_ARCH_HEADER_PATH */
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/*---------------------------------------------------------------------------*/
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#if !MUTEX_CONF_HAS_MUTEX_T
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/**
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* \brief Mutex data type
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*
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* It is possible for the platform to override this with its own typedef. In
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* this scenario, make sure to also define MUTEX_CONF_HAS_MUTEX_T as 1.
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*/
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typedef uint_fast8_t mutex_t;
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#endif
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/*---------------------------------------------------------------------------*/
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#ifndef mutex_try_lock
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/**
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* \brief Try to lock a mutex
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* \param m A pointer to the mutex to be locked
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* \retval true Locking succeeded
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* \retval false Locking failed (the mutex is already locked)
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*
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* This macro will expand to mutex_generic_try_lock() or to a CPU-provided
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* implementation. Platform-independent code should use this macro instead
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* of mutex_generic_try_lock().
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*/
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#define mutex_try_lock(m) mutex_generic_try_lock(m)
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#endif
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#ifndef mutex_unlock
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/**
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* \brief Unlock a previously acquired mutex
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* \param m A pointer to the mutex to be unlocked
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*
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* This macro will expand to mutex_generic_unlock() or to a CPU-provided
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* implementation. Platform-independent code should use this macro instead
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* of mutex_generic_unlock().
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*/
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#define mutex_unlock(m) mutex_generic_unlock(m)
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#endif
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/*---------------------------------------------------------------------------*/
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/**
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* \brief Try to lock a mutex
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* \param mutex A pointer to the mutex to be locked
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* \retval true Locking succeeded
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* \retval false Locking failed (the mutex is already locked)
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*
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* Do not call this function directly. Use the mutex_try_lock() macro instead.
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*/
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bool mutex_generic_try_lock(volatile mutex_t *mutex);
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/**
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* \brief Unlock a previously acquired mutex
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* \param mutex A pointer to the mutex to be unlocked
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*
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* Do not call this function directly. Use the mutex_unlock() macro instead.
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*/
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void mutex_generic_unlock(volatile mutex_t *mutex);
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/*---------------------------------------------------------------------------*/
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#endif /* MUTEX_H_ */
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/*---------------------------------------------------------------------------*/
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/**
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* @}
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* @}
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*/
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