/*
 * Copyright 2015 Stefan Lankes, RWTH Aachen University
 * All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2 (https://www.gnu.org/licenses/gpl-2.0.txt)
 * or the BSD license below:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    * Neither the name of the University nor the names of its contributors
 *      may be used to endorse or promote products derived from this
 *      software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __ISLELOCK_H__
#define __ISLELOCK_H__

#include <hermit/stddef.h>
#include <asm/atomic.h>

typedef struct islelock {
        /// Internal queue
        atomic_int32_t queue;
        /// Internal dequeue
        atomic_int32_t dequeue;
} islelock_t;

inline static int islelock_init(islelock_t* s)
{
        atomic_int32_set(&s->queue, 0);
        atomic_int32_set(&s->dequeue, 1);

        return 0;
}

inline static int islelock_destroy(islelock_t* s)
{
        return 0;
}

static inline int islelock_lock(islelock_t* s)
{
	int ticket;

	ticket = atomic_int32_inc(&s->queue);
	while(atomic_int32_read(&s->dequeue) != ticket) {
		PAUSE;
	}

	return 0;
}

static inline int islelock_unlock(islelock_t* s)
{
        atomic_int32_inc(&s->dequeue);

        return 0;
}

#endif