120 lines
2.8 KiB
C
120 lines
2.8 KiB
C
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#ifndef __ASM_SH_SEMAPHORE_H
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#define __ASM_SH_SEMAPHORE_H
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#include <linux/linkage.h>
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#ifdef __KERNEL__
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/*
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* SMP- and interrupt-safe semaphores.
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*
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* (C) Copyright 1996 Linus Torvalds
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*
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* SuperH verison by Niibe Yutaka
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* (Currently no asm implementation but generic C code...)
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*/
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#include <linux/spinlock.h>
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#include <linux/rwsem.h>
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#include <linux/wait.h>
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#include <asm/system.h>
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#include <asm/atomic.h>
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struct semaphore {
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atomic_t count;
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int sleepers;
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wait_queue_head_t wait;
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};
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#define __SEMAPHORE_INITIALIZER(name, n) \
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{ \
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.count = ATOMIC_INIT(n), \
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.sleepers = 0, \
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.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
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}
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#define __MUTEX_INITIALIZER(name) \
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__SEMAPHORE_INITIALIZER(name,1)
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#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
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struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
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#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
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#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
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static inline void sema_init (struct semaphore *sem, int val)
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{
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/*
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* *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
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*
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* i'd rather use the more flexible initialization above, but sadly
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* GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
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*/
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atomic_set(&sem->count, val);
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sem->sleepers = 0;
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init_waitqueue_head(&sem->wait);
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}
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static inline void init_MUTEX (struct semaphore *sem)
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{
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sema_init(sem, 1);
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}
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static inline void init_MUTEX_LOCKED (struct semaphore *sem)
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{
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sema_init(sem, 0);
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}
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#if 0
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asmlinkage void __down_failed(void /* special register calling convention */);
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asmlinkage int __down_failed_interruptible(void /* params in registers */);
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asmlinkage int __down_failed_trylock(void /* params in registers */);
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asmlinkage void __up_wakeup(void /* special register calling convention */);
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#endif
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asmlinkage void __down(struct semaphore * sem);
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asmlinkage int __down_interruptible(struct semaphore * sem);
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asmlinkage int __down_trylock(struct semaphore * sem);
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asmlinkage void __up(struct semaphore * sem);
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extern spinlock_t semaphore_wake_lock;
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static inline void down(struct semaphore * sem)
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{
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might_sleep();
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if (atomic_dec_return(&sem->count) < 0)
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__down(sem);
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}
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static inline int down_interruptible(struct semaphore * sem)
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{
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int ret = 0;
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might_sleep();
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if (atomic_dec_return(&sem->count) < 0)
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ret = __down_interruptible(sem);
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return ret;
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}
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static inline int down_trylock(struct semaphore * sem)
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{
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int ret = 0;
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if (atomic_dec_return(&sem->count) < 0)
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ret = __down_trylock(sem);
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return ret;
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}
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/*
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* Note! This is subtle. We jump to wake people up only if
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* the semaphore was negative (== somebody was waiting on it).
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*/
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static inline void up(struct semaphore * sem)
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{
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if (atomic_inc_return(&sem->count) <= 0)
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__up(sem);
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}
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#endif
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#endif /* __ASM_SH_SEMAPHORE_H */
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