/*      $NetBSD: lock.h,v 1.10 2023/10/06 11:45:37 skrll 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_ */