107 lines
2.4 KiB
C
107 lines
2.4 KiB
C
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/*
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* linux/include/asm-arm/semaphore.h
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*/
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#ifndef __ASM_ARM_SEMAPHORE_H
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#define __ASM_ARM_SEMAPHORE_H
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#include <linux/linkage.h>
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#include <linux/spinlock.h>
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#include <linux/wait.h>
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#include <linux/rwsem.h>
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#include <asm/atomic.h>
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#include <asm/locks.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_INIT(name, cnt) \
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{ \
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.count = ATOMIC_INIT(cnt), \
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.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \
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}
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#define __MUTEX_INITIALIZER(name) __SEMAPHORE_INIT(name,1)
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#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
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struct semaphore name = __SEMAPHORE_INIT(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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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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static inline int sema_count(struct semaphore *sem)
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{
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return atomic_read(&sem->count);
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}
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/*
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* special register calling convention
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*/
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asmlinkage void __down_failed(void);
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asmlinkage int __down_interruptible_failed(void);
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asmlinkage int __down_trylock_failed(void);
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asmlinkage void __up_wakeup(void);
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extern void __down(struct semaphore * sem);
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extern int __down_interruptible(struct semaphore * sem);
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extern int __down_trylock(struct semaphore * sem);
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extern void __up(struct semaphore * sem);
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/*
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* This is ugly, but we want the default case to fall through.
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* "__down" is the actual routine that waits...
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*/
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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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__down_op(sem, __down_failed);
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}
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/*
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* This is ugly, but we want the default case to fall through.
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* "__down_interruptible" is the actual routine that waits...
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*/
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static inline int down_interruptible (struct semaphore * sem)
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{
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might_sleep();
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return __down_op_ret(sem, __down_interruptible_failed);
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}
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static inline int down_trylock(struct semaphore *sem)
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{
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return __down_op_ret(sem, __down_trylock_failed);
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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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* The default case (no contention) will result in NO
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* jumps for both down() and up().
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*/
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static inline void up(struct semaphore * sem)
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{
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__up_op(sem, __up_wakeup);
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}
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#endif
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