83 lines
3.1 KiB
C
83 lines
3.1 KiB
C
/*
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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 arm
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*
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* Arm Cortex-M implementation of mutexes using the LDREX, STREX and DMB
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* instructions.
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*
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* @{
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*/
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/*---------------------------------------------------------------------------*/
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#ifndef MUTEX_CORTEX_H_
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#define MUTEX_CORTEX_H_
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/*---------------------------------------------------------------------------*/
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#include "contiki.h"
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#ifdef CMSIS_CONF_HEADER_PATH
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#include CMSIS_CONF_HEADER_PATH
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#endif
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#include <stdint.h>
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#include <stdbool.h>
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/*---------------------------------------------------------------------------*/
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#define mutex_try_lock(m) mutex_cortex_try_lock(m)
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#define mutex_unlock(m) mutex_cortex_unlock(m)
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/*---------------------------------------------------------------------------*/
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#define MUTEX_CONF_HAS_MUTEX_T 1
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typedef uint8_t mutex_t;
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/*---------------------------------------------------------------------------*/
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static inline bool
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mutex_cortex_try_lock(volatile mutex_t *mutex)
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{
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int status = 1;
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if(__LDREXB(mutex) == 0) {
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status = __STREXB(1, mutex);
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}
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__DMB();
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return status == 0 ? true : false;
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}
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/*---------------------------------------------------------------------------*/
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static inline void
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mutex_cortex_unlock(volatile mutex_t *mutex)
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{
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__DMB();
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*mutex = 0;
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}
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/*---------------------------------------------------------------------------*/
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#endif /* MUTEX_CORTEX_H_ */
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/*---------------------------------------------------------------------------*/
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/** @} */
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