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