/*      $NetBSD: lock.h,v 1.18 2026/01/09 22:54:33 jmcneill Exp $       */

/*-
 * Copyright (c) 2000, 2007 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe and Andrew Doran.
 *
 * 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 _POWERPC_LOCK_H_
#define _POWERPC_LOCK_H_

#ifdef _KERNEL_OPT
#include "opt_ppcarch.h"
#endif

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_clear(__cpu_simple_lock_t *__ptr)
{
        *__ptr = __SIMPLELOCK_UNLOCKED;
}

static __inline void
__cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
{
        *__ptr = __SIMPLELOCK_LOCKED;
}

static __inline void
__cpu_simple_lock_init(__cpu_simple_lock_t *alp)
{
        *alp = __SIMPLELOCK_UNLOCKED;
}

static __inline void
__cpu_simple_lock(__cpu_simple_lock_t *alp)
{
        int old;

        __asm volatile ("       \
                                \n\
1:      lwarx   %0,0,%1         \n\
        cmpwi   %0,%2           \n\
        beq+    3f              \n\
2:      lwzx    %0,0,%1         \n\
        cmpwi   %0,%2           \n\
        beq+    1b              \n\
        b       2b              \n\
3:                              \n"
#ifdef IBM405_ERRATA77
        "dcbt   0,%1            \n"
#elif defined(PPC_IBMESPRESSO)
        "dcbst  0,%1            \n"
#endif
        "stwcx. %3,0,%1         \n\
        bne-    1b              \n\
        isync                   \n\
                                \n"
        : "=&r"(old)
        : "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED)
        : "memory");
}

static __inline int
__cpu_simple_lock_try(__cpu_simple_lock_t *alp)
{
        int old, dummy;

        __asm volatile ("       \
                                \n\
1:      lwarx   %0,0,%1         \n\
        cmpwi   %0,%2           \n\
        bne     2f              \n"
#ifdef IBM405_ERRATA77
        "dcbt   0,%1            \n"
#elif defined(PPC_IBMESPRESSO)
        "dcbst  0,%1            \n"
#endif
        "stwcx. %3,0,%1         \n\
        bne-    1b              \n\
2:                              \n"
#ifdef IBM405_ERRATA77
        "dcbt   0,%4            \n"
#elif defined(PPC_IBMESPRESSO)
        "dcbst  0,%4            \n"
#endif
        "stwcx. %3,0,%4         \n\
        isync                   \n\
                                \n"
        : "=&r"(old)
        : "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED),
          "r"(&dummy)
        : "memory");

        return (old == __SIMPLELOCK_UNLOCKED);
}

static __inline void
__cpu_simple_unlock(__cpu_simple_lock_t *alp)
{
        __asm volatile ("sync");
        *alp = __SIMPLELOCK_UNLOCKED;
}

#endif /* _POWERPC_LOCK_H_ */