/*
 * Copyright (C) 2012 Thomas Preud'homme <thomas.preud-homme@lip6.fr>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef _CSQ_COMMON_COMM_H_
#define _CSQ_COMMON_COMM_H_ 1

/* Non standard include */
#include <commtech.h>

#ifndef BUF_SIZE
#define BUF_SIZE (64 * CACHE_LINE_SIZE)
#endif

#ifndef SLOTS
#define SLOTS 64 /* Value used in the article, section V.A */
#endif
#define SUB_SLOTS (BUF_SIZE / sizeof(void *))

struct lvl_2
{
	void * volatile chunk[SUB_SLOTS];
	volatile unsigned int flag : 1;
} __attribute__ ((aligned (CACHE_LINE_SIZE)));

struct channel
{
	struct lvl_2 queue[SLOTS] __attribute__ ((aligned (CACHE_LINE_SIZE)));
	unsigned int head __attribute__ ((aligned(CACHE_LINE_SIZE)));
	unsigned int tail __attribute__ ((aligned(CACHE_LINE_SIZE)));
};

__BEGIN_DECLS

// TODO: Make it send only one data
static inline void send(struct channel *channel, void **addr)
{
	static __thread unsigned int chkidx = 0;

	// If all slots are full, spin
	if (!chkidx)
		while (channel->queue[channel->tail].flag);

	// Enqueue a data item
	channel->queue[channel->tail].chunk[chkidx++] = addr;
	if (!(chkidx % SUB_SLOTS))
	{
		chkidx = 0;
		channel->queue[channel->tail].flag = 1;
		channel->tail = (channel->tail + 1) % SLOTS;
	}
}

__END_DECLS

#endif