sync.h

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/*
 * This file is part of the libopencm3 project.
 *
 * Copyright (C) 2012 Fergus Noble <fergusnoble@gmail.com>
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef LIBOPENCM3_CM3_SYNC_H
#define LIBOPENCM3_CM3_SYNC_H
 
#include "common.h"
 
BEGIN_DECLS
 
void __dmb(void);
 
/* Implements synchronisation primitives as discussed in the ARM document
 * DHT0008A (ID081709) "ARM Synchronization Primitives" and the ARM v7-M
 * Architecture Reference Manual.
*/
 
/* --- Exclusive load and store instructions ------------------------------- */
 
/* Those are defined only on CM3 or CM4 */
#if defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7EM__)
 
uint32_t __ldrex(volatile uint32_t *addr);
uint32_t __strex(uint32_t val, volatile uint32_t *addr);
 
/* --- Convenience functions ----------------------------------------------- */
 
/* Here we implement some simple synchronisation primitives. */
 
typedef uint32_t mutex_t;
 
#define MUTEX_UNLOCKED 0
#define MUTEX_LOCKED     1
 
void mutex_lock(mutex_t *m);
uint32_t mutex_trylock(mutex_t *m);
void mutex_unlock(mutex_t *m);
 
#endif
 
END_DECLS
 
#endif