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/*
* linux/include/asm-arm/semaphore.h
*/
#ifndef __ASM_ARM_SEMAPHORE_H
#define __ASM_ARM_SEMAPHORE_H
#include <linux/linkage.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
#include <asm/atomic.h>
#include <asm/locks.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INIT(name, cnt) \
{ \
.count = ATOMIC_INIT(cnt), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INIT(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
static inline void sema_init(struct semaphore *sem, int val)
{
atomic_set(&sem->count, val);
sem->sleepers = 0;
init_waitqueue_head(&sem->wait);
}
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);
}
/*
* special register calling convention
*/
asmlinkage void __down_failed(void);
asmlinkage int __down_interruptible_failed(void);
asmlinkage int __down_trylock_failed(void);
asmlinkage void __up_wakeup(void);
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern int __down_trylock(struct semaphore * sem);
extern void __up(struct semaphore * sem);
/*
* This is ugly, but we want the default case to fall through.
* "__down" is the actual routine that waits...
*/
static inline void down(struct semaphore * sem)
{
might_sleep();
__down_op(sem, __down_failed);
}
/*
* This is ugly, but we want the default case to fall through.
* "__down_interruptible" is the actual routine that waits...
*/
static inline int down_interruptible (struct semaphore * sem)
{
might_sleep();
return __down_op_ret(sem, __down_interruptible_failed);
}
static inline int down_trylock(struct semaphore *sem)
{
return __down_op_ret(sem, __down_trylock_failed);
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
static inline void up(struct semaphore * sem)
{
__up_op(sem, __up_wakeup);
}
#endif
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