1 /* SMP- and interrupt-safe semaphores.
2 * PA-RISC version by Matthew Wilcox
4 * Linux/PA-RISC Project (http://www.parisc-linux.org/)
5 * Copyright (C) 1996 Linus Torvalds
6 * Copyright (C) 1999-2001 Matthew Wilcox < willy at debian d0T org >
7 * Copyright (C) 2000 Grant Grundler < grundler a debian org >
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #ifndef _ASM_PARISC_SEMAPHORE_H
25 #define _ASM_PARISC_SEMAPHORE_H
27 #include <linux/spinlock.h>
28 #include <linux/wait.h>
29 #include <linux/rwsem.h>
31 #include <asm/system.h>
34 * The `count' is initialised to the number of people who are allowed to
35 * take the lock. (Normally we want a mutex, so this is `1'). if
36 * `count' is positive, the lock can be taken. if it's 0, no-one is
37 * waiting on it. if it's -1, at least one task is waiting.
42 wait_queue_head_t wait;
49 # define __SEM_DEBUG_INIT(name) \
50 , (long)&(name).__magic
52 # define __SEM_DEBUG_INIT(name)
55 #define __SEMAPHORE_INITIALIZER(name,count) \
56 { SPIN_LOCK_UNLOCKED, count, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
57 __SEM_DEBUG_INIT(name) }
59 #define __MUTEX_INITIALIZER(name) \
60 __SEMAPHORE_INITIALIZER(name,1)
62 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
63 struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
65 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
66 #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
68 extern inline void sema_init (struct semaphore *sem, int val)
70 *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
73 static inline void init_MUTEX (struct semaphore *sem)
78 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
83 static inline int sem_getcount(struct semaphore *sem)
88 asmlinkage void __down(struct semaphore * sem);
89 asmlinkage int __down_interruptible(struct semaphore * sem);
90 asmlinkage void __up(struct semaphore * sem);
92 /* Semaphores can be `tried' from irq context. So we have to disable
93 * interrupts while we're messing with the semaphore. Sorry.
96 extern __inline__ void down(struct semaphore * sem)
99 CHECK_MAGIC(sem->__magic);
102 spin_lock_irq(&sem->sentry);
103 if (sem->count > 0) {
108 spin_unlock_irq(&sem->sentry);
111 extern __inline__ int down_interruptible(struct semaphore * sem)
115 CHECK_MAGIC(sem->__magic);
118 spin_lock_irq(&sem->sentry);
119 if (sem->count > 0) {
122 ret = __down_interruptible(sem);
124 spin_unlock_irq(&sem->sentry);
129 * down_trylock returns 0 on success, 1 if we failed to get the lock.
130 * May not sleep, but must preserve irq state
132 extern __inline__ int down_trylock(struct semaphore * sem)
136 CHECK_MAGIC(sem->__magic);
139 spin_lock_irqsave(&sem->sentry, flags);
140 count = sem->count - 1;
143 spin_unlock_irqrestore(&sem->sentry, flags);
148 * Note! This is subtle. We jump to wake people up only if
149 * the semaphore was negative (== somebody was waiting on it).
151 extern __inline__ void up(struct semaphore * sem)
155 CHECK_MAGIC(sem->__magic);
157 spin_lock_irqsave(&sem->sentry, flags);
158 if (sem->count < 0) {
163 spin_unlock_irqrestore(&sem->sentry, flags);
166 #endif /* _ASM_PARISC_SEMAPHORE_H */