rockbox/firmware/kernel/include/corelock.h

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Ulf Ralberg
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef CORELOCK_H
#define CORELOCK_H
#include "config.h"
#ifndef HAVE_CORELOCK_OBJECT
/* No atomic corelock op needed or just none defined */
#define corelock_init(cl) \
do {} while (0)
#define corelock_lock(cl) \
do {} while (0)
#define corelock_try_lock(cl) \
do {} while (0)
#define corelock_unlock(cl) \
do {} while (0)
#else
/* No reliable atomic instruction available - use Peterson's algorithm */
struct corelock
{
volatile unsigned char myl[NUM_CORES];
volatile unsigned char turn;
} __attribute__((packed));
/* Too big to inline everywhere */
extern void corelock_init(struct corelock *cl);
extern void corelock_lock(struct corelock *cl);
extern int corelock_try_lock(struct corelock *cl);
extern void corelock_unlock(struct corelock *cl);
#endif /* HAVE_CORELOCK_OBJECT */
#endif /* CORELOCK_H */