numam-dpdk/drivers/net/avp/rte_avp_fifo.h

/*-
 *   This file is provided under a dual BSD/LGPLv2 license.  When using or
 *   redistributing this file, you may do so under either license.
 *
 *   GNU LESSER GENERAL PUBLIC LICENSE
 *
 *   Copyright(c) 2010-2013 Intel Corporation. All rights reserved.
 *   Copyright(c) 2014 Wind River Systems, Inc. All rights reserved.
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of version 2.1 of the GNU Lesser General Public License
 *   as published by the Free Software Foundation.
 *
 *   This program 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.
 *
 *   Contact Information:
 *   Wind River Systems, Inc.
 *
 *
 *   BSD LICENSE
 *
 *   Copyright(c) 2010-2013 Intel Corporation. All rights reserved.
 *   Copyright(c) 2013-2017 Wind River Systems, Inc. All rights reserved.
 *   All rights reserved.
 *
 *   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 Intel Corporation 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 COPYRIGHT
 *    OWNER 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
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 *    (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 _RTE_AVP_FIFO_H_
#define _RTE_AVP_FIFO_H_

#ifdef __KERNEL__
/* Write memory barrier for kernel compiles */
#define AVP_WMB() smp_wmb()
/* Read memory barrier for kernel compiles */
#define AVP_RMB() smp_rmb()
#else
/* Write memory barrier for userspace compiles */
#define AVP_WMB() rte_wmb()
/* Read memory barrier for userspace compiles */
#define AVP_RMB() rte_rmb()
#endif

#ifndef __KERNEL__
/**
 * Initializes the avp fifo structure
 */
static inline void
avp_fifo_init(struct rte_avp_fifo *fifo, unsigned int size)
{
	/* Ensure size is power of 2 */
	if (size & (size - 1))
		rte_panic("AVP fifo size must be power of 2\n");

	fifo->write = 0;
	fifo->read = 0;
	fifo->len = size;
	fifo->elem_size = sizeof(void *);
}
#endif

/**
 * Adds num elements into the fifo. Return the number actually written
 */
static inline unsigned
avp_fifo_put(struct rte_avp_fifo *fifo, void **data, unsigned int num)
{
	unsigned int i = 0;
	unsigned int fifo_write = fifo->write;
	unsigned int fifo_read = fifo->read;
	unsigned int new_write = fifo_write;

	for (i = 0; i < num; i++) {
		new_write = (new_write + 1) & (fifo->len - 1);

		if (new_write == fifo_read)
			break;
		fifo->buffer[fifo_write] = data[i];
		fifo_write = new_write;
	}
	AVP_WMB();
	fifo->write = fifo_write;
	return i;
}

/**
 * Get up to num elements from the fifo. Return the number actually read
 */
static inline unsigned int
avp_fifo_get(struct rte_avp_fifo *fifo, void **data, unsigned int num)
{
	unsigned int i = 0;
	unsigned int new_read = fifo->read;
	unsigned int fifo_write = fifo->write;

	if (new_read == fifo_write)
		return 0; /* empty */

	for (i = 0; i < num; i++) {
		if (new_read == fifo_write)
			break;

		data[i] = fifo->buffer[new_read];
		new_read = (new_read + 1) & (fifo->len - 1);
	}
	AVP_RMB();
	fifo->read = new_read;
	return i;
}

/**
 * Get the num of elements in the fifo
 */
static inline unsigned int
avp_fifo_count(struct rte_avp_fifo *fifo)
{
	return (fifo->len + fifo->write - fifo->read) & (fifo->len - 1);
}

/**
 * Get the num of available elements in the fifo
 */
static inline unsigned int
avp_fifo_free_count(struct rte_avp_fifo *fifo)
{
	return (fifo->read - fifo->write - 1) & (fifo->len - 1);
}

#endif /* _RTE_AVP_FIFO_H_ */