/*	$NetBSD: lock.h,v 1.9 2022/02/12 17:17:53 riastradh Exp $	*/

/*-
 * Copyright (c) 2000 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Machine-dependent spin lock operations.
 */

#ifndef _IA64_LOCK_H_
#define	_IA64_LOCK_H_

static __inline int
__SIMPLELOCK_LOCKED_P(const __cpu_simple_lock_t *__ptr)
{
	return *__ptr == __SIMPLELOCK_LOCKED;
}

static __inline int
__SIMPLELOCK_UNLOCKED_P(const __cpu_simple_lock_t *__ptr)
{
	return *__ptr == __SIMPLELOCK_UNLOCKED;
}

static __inline void
__cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
{

	*__ptr = __SIMPLELOCK_LOCKED;
}

static __inline void
__cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
{

	*__ptr = __SIMPLELOCK_UNLOCKED;
}

#ifdef _KERNEL

#define	SPINLOCK_SPIN_HOOK	/* nothing */
#define	SPINLOCK_BACKOFF_HOOK	/* XXX ia64_pause() */

#endif

static __inline void __cpu_simple_lock_init(__cpu_simple_lock_t *)
	__unused;
static __inline void __cpu_simple_lock(__cpu_simple_lock_t *)
	__unused;
static __inline int __cpu_simple_lock_try(__cpu_simple_lock_t *)
	__unused;
static __inline void __cpu_simple_unlock(__cpu_simple_lock_t *)
	__unused;

static __inline void
__cpu_simple_lock_init(__cpu_simple_lock_t *lockp)
{

	*lockp = __SIMPLELOCK_UNLOCKED;
}

static __inline int
__cpu_simple_lock_try(__cpu_simple_lock_t *lockp)
{
	uint8_t val;

	val = __SIMPLELOCK_LOCKED;
	__asm volatile ("xchg1 %0=[%1],%2" : 
	    "=r" (val)
	    :"r" (lockp), "r" (val)
	    :"memory");
	return val == __SIMPLELOCK_UNLOCKED;
}

static __inline void
__cpu_simple_lock(__cpu_simple_lock_t *lockp)
{

	while (!__cpu_simple_lock_try(lockp))
		/* nothing */;
	__insn_barrier();
}

static __inline void
__cpu_simple_unlock(__cpu_simple_lock_t *lockp)
{

	__insn_barrier();
	*lockp = __SIMPLELOCK_UNLOCKED;
}

static __inline void
ia64_pause(void)
{
	__asm __volatile("hint @pause" ::: "memory");
}

#endif /* _IA64_LOCK_H_ */