Contiki-NG
mutex-cortex.h
1/*
2 * Copyright (c) 2017, George Oikonomou - http://www.spd.gr
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the copyright holder nor the names of its
15 * contributors may be used to endorse or promote products derived
16 * from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
22 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
25 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
27 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
29 * OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31/*---------------------------------------------------------------------------*/
32/**
33 * \addtogroup arm
34 *
35 * Arm Cortex-M implementation of mutexes using the LDREX, STREX and DMB
36 * instructions.
37 *
38 * @{
39 */
40/*---------------------------------------------------------------------------*/
41#ifndef MUTEX_CORTEX_H_
42#define MUTEX_CORTEX_H_
43/*---------------------------------------------------------------------------*/
44#include "contiki.h"
45
46#ifdef CMSIS_CONF_HEADER_PATH
47#include CMSIS_CONF_HEADER_PATH
48#endif
49
50#include <stdint.h>
51#include <stdbool.h>
52/*---------------------------------------------------------------------------*/
53#define mutex_try_lock(m) mutex_cortex_try_lock(m)
54#define mutex_unlock(m) mutex_cortex_unlock(m)
55/*---------------------------------------------------------------------------*/
56#define MUTEX_CONF_HAS_MUTEX_T 1
57typedef uint8_t mutex_t;
58/*---------------------------------------------------------------------------*/
59static inline bool
60mutex_cortex_try_lock(volatile mutex_t *mutex)
61{
62 do {
63 if(__LDREXB(mutex) != 0) {
64 return false;
65 }
66 } while(__STREXB(1, mutex) != 0);
67
68 __DMB();
69
70 return true;
71}
72/*---------------------------------------------------------------------------*/
73static inline void
74mutex_cortex_unlock(volatile mutex_t *mutex)
75{
76 __DMB();
77 *mutex = 0;
78}
79/*---------------------------------------------------------------------------*/
80#endif /* MUTEX_CORTEX_H_ */
81/*---------------------------------------------------------------------------*/
82/** @} */
uint_fast8_t mutex_t
Mutex data type.
Definition: mutex.h:77