1/*
2 *  include/asm-s390/semaphore.h
3 *
4 *  S390 version
5 *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
6 *
7 *  Derived from "include/asm-i386/semaphore.h"
8 *    (C) Copyright 1996 Linus Torvalds
9 */
10
11#ifndef _S390_SEMAPHORE_H
12#define _S390_SEMAPHORE_H
13
14#include <asm/system.h>
15#include <asm/atomic.h>
16#include <linux/wait.h>
17#include <linux/rwsem.h>
18
19struct semaphore {
20	atomic_t count;
21	int sleepers;
22	wait_queue_head_t wait;
23};
24
25#define __SEM_DEBUG_INIT(name)
26
27#define __SEMAPHORE_INITIALIZER(name,count) \
28{ ATOMIC_INIT(count), 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
29	__SEM_DEBUG_INIT(name) }
30
31#define __MUTEX_INITIALIZER(name) \
32	__SEMAPHORE_INITIALIZER(name,1)
33
34#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
35	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
36
37#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
38#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
39
40static inline void sema_init (struct semaphore *sem, int val)
41{
42	*sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
43}
44
45static inline void init_MUTEX (struct semaphore *sem)
46{
47	sema_init(sem, 1);
48}
49
50static inline void init_MUTEX_LOCKED (struct semaphore *sem)
51{
52	sema_init(sem, 0);
53}
54
55asmlinkage void __down_failed(void /* special register calling convention */);
56asmlinkage int  __down_failed_interruptible(void  /* params in registers */);
57asmlinkage int  __down_failed_trylock(void  /* params in registers */);
58asmlinkage void __up_wakeup(void /* special register calling convention */);
59
60asmlinkage void __down(struct semaphore * sem);
61asmlinkage int  __down_interruptible(struct semaphore * sem);
62asmlinkage int  __down_trylock(struct semaphore * sem);
63asmlinkage void __up(struct semaphore * sem);
64
65static inline void down(struct semaphore * sem)
66{
67	if (atomic_dec_return(&sem->count) < 0)
68		__down(sem);
69}
70
71static inline int down_interruptible(struct semaphore * sem)
72{
73	int ret = 0;
74
75	if (atomic_dec_return(&sem->count) < 0)
76		ret = __down_interruptible(sem);
77	return ret;
78}
79
80static inline int down_trylock(struct semaphore * sem)
81{
82	int ret = 0;
83
84	if (atomic_dec_return(&sem->count) < 0)
85		ret = __down_trylock(sem);
86	return ret;
87}
88
89static inline void up(struct semaphore * sem)
90{
91	if (atomic_inc_return(&sem->count) <= 0)
92		__up(sem);
93}
94
95static inline int sem_getcount(struct semaphore *sem)
96{
97	return atomic_read(&sem->count);
98}
99
100#endif
101