/*
 * 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 _MCRINGBUFFER_COMMON_H_
#define _MCRINGBUFFER_COMMON_H_ 1

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

#ifndef SHARED_SPACE_SIZE
#define SHARED_SPACE_SIZE (250 * CACHE_LINE_SIZE) // Check with batchSize
#endif
#define SHARED_SPACE_VOIDPTR (SHARED_SPACE_SIZE / sizeof(void *))

struct control
{
	volatile unsigned int read;
	volatile unsigned int write;
};

struct cons
{
	unsigned int localWrite;
	unsigned int nextRead;
	unsigned int rBatch;
};

struct prod
{
	unsigned int localRead;
	unsigned int nextWrite;
	unsigned int wBatch;
};


struct channel
{
	struct control ctrl __attribute__ ((aligned (CACHE_LINE_SIZE)));
	struct prod prod __attribute__ ((aligned (CACHE_LINE_SIZE)));
	struct cons cons __attribute__ ((aligned (CACHE_LINE_SIZE)));
	void * volatile *shared_space __attribute__ ((aligned (CACHE_LINE_SIZE))); // Align only to isolate cons on its cache line
};

__BEGIN_DECLS

extern const unsigned int batchSize;

static inline void send(struct channel *channel, void **addr)
{
	while (1)
	{
		unsigned int afterNextWrite;

		afterNextWrite = (channel->prod.nextWrite + 1) % SHARED_SPACE_VOIDPTR;
		if (afterNextWrite == channel->prod.localRead)
		{
			if (afterNextWrite == channel->ctrl.read)
				continue;
			channel->prod.localRead = channel->ctrl.read;
		}
		channel->shared_space[channel->prod.nextWrite] = addr;
		channel->prod.nextWrite = afterNextWrite;
		channel->prod.wBatch++;
		if (channel->prod.wBatch >= batchSize)
		{
			channel->ctrl.write = channel->prod.nextWrite;
			channel->prod.wBatch = 0;
		}
		break;
	}
}

__END_DECLS

#endif