mutex.h revision 1.1 
1/*	$NetBSD: mutex.h,v 1.1 2014/09/03 19:34:26 matt Exp $	*/
2
3/*-
4 * Copyright (c) 2002, 2007 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe and Andrew Doran.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#ifndef _OR1K_MUTEX_H_
33#define	_OR1K_MUTEX_H_
34
35#ifndef __MUTEX_PRIVATE
36
37struct kmutex {
38	uintptr_t	mtx_pad1;
39};
40
41#else	/* __MUTEX_PRIVATE */
42
43struct kmutex {
44	union {
45		/* Adaptive mutex */
46		volatile uintptr_t	mtxa_owner;
47
48		/* Spin mutex */
49		struct {
50			/*
51			 * Since the low bit of mtax_owner is used to flag this
52			 * mutex as a spin mutex, we can't use the first byte
53			 * or the last byte to store the ipl or lock values.
54			 */
55			volatile uint8_t	mtxs_dummy;
56			ipl_cookie_t		mtxs_ipl;
57			__cpu_simple_lock_t	mtxs_lock;
58			volatile uint8_t	mtxs_unused;
59		} s;
60	} u;
61};
62
63#define	mtx_owner		u.mtxa_owner
64#define	mtx_ipl			u.s.mtxs_ipl
65#define	mtx_lock		u.s.mtxs_lock
66
67#if 0
68#define	__HAVE_MUTEX_STUBS		1
69#define	__HAVE_SPIN_MUTEX_STUBS		1
70#endif
71#define	__HAVE_SIMPLE_MUTEXES		1
72
73/*
74 * MUTEX_RECEIVE: no memory barrier required; we're synchronizing against
75 * interrupts, not multiple processors.
76 */
77#ifdef MULTIPROCESSOR
78#define	MUTEX_RECEIVE(mtx)		membar_consumer()
79#else
80#define	MUTEX_RECEIVE(mtx)		/* nothing */
81#endif
82
83/*
84 * MUTEX_GIVE: no memory barrier required; same reason.
85 */
86#ifdef MULTIPROCESSOR
87#define	MUTEX_GIVE(mtx)			membar_producer()
88#else
89#define	MUTEX_GIVE(mtx)			/* nothing */
90#endif
91
92#define	MUTEX_CAS(p, o, n)		\
93    (atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o))
94
95#endif	/* __MUTEX_PRIVATE */
96
97#endif /* _OR1K_MUTEX_H_ */
98