/*-
 * Copyright (c) 2014 Chelsio Communications, Inc.
 * All rights reserved.
 * Written by: Navdeep Parhar <np@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 * $FreeBSD: releng/12.4/sys/net/mp_ring.h 344092 2019-02-13 13:09:16Z marius $
 *
 */

#ifndef __NET_MP_RING_H
#define __NET_MP_RING_H

#ifndef _KERNEL
#error "no user-serviceable parts inside"
#endif

struct ifmp_ring;
typedef u_int (*mp_ring_drain_t)(struct ifmp_ring *, u_int, u_int);
typedef u_int (*mp_ring_can_drain_t)(struct ifmp_ring *);
typedef void (*mp_ring_serial_t)(struct ifmp_ring *);

#if defined(__powerpc__) || defined(__mips__) || defined(__i386__)
#define MP_RING_NO_64BIT_ATOMICS
#endif

struct ifmp_ring {
	volatile uint64_t	state __aligned(CACHE_LINE_SIZE);

	int			size __aligned(CACHE_LINE_SIZE);
	void *			cookie;
	struct malloc_type *	mt;
	mp_ring_drain_t		drain;
	mp_ring_can_drain_t	can_drain;	/* cheap, may be unreliable */
	counter_u64_t		enqueues;
	counter_u64_t		drops;
	counter_u64_t		starts;
	counter_u64_t		stalls;
	counter_u64_t		restarts;	/* recovered after stalling */
	counter_u64_t		abdications;
#ifdef MP_RING_NO_64BIT_ATOMICS
	struct mtx		lock;
#endif
	void * volatile		items[] __aligned(CACHE_LINE_SIZE);
};

int ifmp_ring_alloc(struct ifmp_ring **, int, void *, mp_ring_drain_t,
    mp_ring_can_drain_t, struct malloc_type *, int);
void ifmp_ring_free(struct ifmp_ring *);
int ifmp_ring_enqueue(struct ifmp_ring *, void **, int, int, int);
void ifmp_ring_check_drainage(struct ifmp_ring *, int);
void ifmp_ring_reset_stats(struct ifmp_ring *);
int ifmp_ring_is_idle(struct ifmp_ring *);
int ifmp_ring_is_stalled(struct ifmp_ring *r);
#endif
