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#ifndef _PPC_SEMAPHORE_H
#define _PPC_SEMAPHORE_H
/*
* SMP- and interrupt-safe semaphores..
*
* (C) Copyright 1996 Linus Torvalds
* Adapted for PowerPC by Gary Thomas and Paul Mackerras
*/
#include <asm/atomic.h>
struct semaphore {
atomic_t count;
atomic_t waking;
struct wait_queue * wait;
};
#define MUTEX ((struct semaphore) { ATOMIC_INIT(1), ATOMIC_INIT(0), NULL })
#define MUTEX_LOCKED ((struct semaphore) { ATOMIC_INIT(0), ATOMIC_INIT(0), NULL })
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern void __up(struct semaphore * sem);
#define sema_init(sem, val) atomic_set(&((sem)->count), (val))
/*
* These two _must_ execute atomically wrt each other.
*
* This is trivially done with load_locked/store_cond,
* i.e. load with reservation and store conditional on the ppc.
*/
static inline void wake_one_more(struct semaphore * sem)
{
atomic_inc(&sem->waking);
}
static inline int waking_non_zero(struct semaphore *sem, struct task_struct *tsk)
{
int ret, tmp;
__asm__ __volatile__(
"1: lwarx %1,0,%2\n"
" cmpwi 0,%1,0\n"
" addic %1,%1,-1\n"
" ble- 2f\n"
" stwcx. %1,0,%2\n"
" bne- 1b\n"
" li %0,1\n"
"2:"
: "=r" (ret), "=&r" (tmp)
: "r" (&sem->waking), "0" (0)
: "cr0", "memory");
return ret;
}
extern inline void down(struct semaphore * sem)
{
if (atomic_dec_return(&sem->count) < 0)
__down(sem);
}
extern inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
if (atomic_dec_return(&sem->count) < 0)
ret = __down_interruptible(sem);
return ret;
}
extern inline void up(struct semaphore * sem)
{
if (atomic_inc_return(&sem->count) <= 0)
__up(sem);
}
#endif /* !(_PPC_SEMAPHORE_H) */
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