1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
/* SMP- and interrupt-safe semaphores.
* PA-RISC version by Matthew Wilcox
*
* Linux/PA-RISC Project (http://www.parisc-linux.org/)
* Copyright (C) 1996 Linus Torvalds
* Copyright (C) 1999-2001 Matthew Wilcox < willy at debian d0T org >
* Copyright (C) 2000 Grant Grundler < grundler a debian org >
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _ASM_PARISC_SEMAPHORE_H
#define _ASM_PARISC_SEMAPHORE_H
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
#include <asm/system.h>
/*
* The `count' is initialised to the number of people who are allowed to
* take the lock. (Normally we want a mutex, so this is `1'). if
* `count' is positive, the lock can be taken. if it's 0, no-one is
* waiting on it. if it's -1, at least one task is waiting.
*/
struct semaphore {
spinlock_t sentry;
int count;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.sentry = SPIN_LOCK_UNLOCKED, \
.count = n, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
static inline void sema_init (struct semaphore *sem, int val)
{
*sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
static inline int sem_getcount(struct semaphore *sem)
{
return sem->count;
}
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
/* Semaphores can be `tried' from irq context. So we have to disable
* interrupts while we're messing with the semaphore. Sorry.
*/
static inline void down(struct semaphore * sem)
{
might_sleep();
spin_lock_irq(&sem->sentry);
if (sem->count > 0) {
sem->count--;
} else {
__down(sem);
}
spin_unlock_irq(&sem->sentry);
}
static inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
might_sleep();
spin_lock_irq(&sem->sentry);
if (sem->count > 0) {
sem->count--;
} else {
ret = __down_interruptible(sem);
}
spin_unlock_irq(&sem->sentry);
return ret;
}
/*
* down_trylock returns 0 on success, 1 if we failed to get the lock.
* May not sleep, but must preserve irq state
*/
static inline int down_trylock(struct semaphore * sem)
{
unsigned long flags;
int count;
spin_lock_irqsave(&sem->sentry, flags);
count = sem->count - 1;
if (count >= 0)
sem->count = count;
spin_unlock_irqrestore(&sem->sentry, flags);
return (count < 0);
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
*/
static inline void up(struct semaphore * sem)
{
unsigned long flags;
spin_lock_irqsave(&sem->sentry, flags);
if (sem->count < 0) {
__up(sem);
} else {
sem->count++;
}
spin_unlock_irqrestore(&sem->sentry, flags);
}
#endif /* _ASM_PARISC_SEMAPHORE_H */
|
