include/asm-sh/semaphore.h

Name: Public Git Hosting - davej-history.git/blob - include/asm-sh/semaphore.h
Rating: 4.7 (2371 reviews)
 1 #ifndef __ASM_SH_SEMAPHORE_H
 2 #define __ASM_SH_SEMAPHORE_H
 3
 4 #include <linux/linkage.h>
 5
 6 /*
 7  * SMP- and interrupt-safe semaphores.
 8  *
 9  * (C) Copyright 1996 Linus Torvalds
 10  *
 11  * SuperH verison by Niibe Yutaka
 12  *
 13  */
 14
 15 #include <linux/spinlock.h>
 16
 17 #include <asm/system.h>
 18 #include <asm/atomic.h>
 19
 20 struct semaphore {
 21  atomic_t count;
 22 int waking;
 23  wait_queue_head_t wait;
 24 #if WAITQUEUE_DEBUG
 25 long __magic;
 26 #endif
 27 };
 28
 29 #if WAITQUEUE_DEBUG
 30 # define __SEM_DEBUG_INIT(name) \
 31  , (int)&(name).__magic
 32 #else
 33 # define __SEM_DEBUG_INIT(name)
 34 #endif
 35
 36 #define __SEMAPHORE_INITIALIZER(name,count) \
 37 { ATOMIC_INIT(count), 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
 38  __SEM_DEBUG_INIT(name) }
 39
 40 #define __MUTEX_INITIALIZER(name) \
 41  __SEMAPHORE_INITIALIZER(name,1)
 42
 43 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
 44  struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
 45
 46 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
 47 #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
 48
 49 extern inlinevoidsema_init(struct semaphore *sem,int val)
 50 {
 51 /*
 52  * *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
 53  *
 54  * i'd rather use the more flexible initialization above, but sadly
 55  * GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well.
 56  */
 57 atomic_set(&sem->count, val);
 58  sem->waking =0;
 59 init_waitqueue_head(&sem->wait);
 60 #if WAITQUEUE_DEBUG
 61  sem->__magic = (int)&sem->__magic;
 62 #endif
 63 }
 64
 65 staticinlinevoidinit_MUTEX(struct semaphore *sem)
 66 {
 67 sema_init(sem,1);
 68 }
 69
 70 staticinlinevoidinit_MUTEX_LOCKED(struct semaphore *sem)
 71 {
 72 sema_init(sem,0);
 73 }
 74
 75 asmlinkage void__down_failed(void/* special register calling convention */);
 76 asmlinkage int__down_failed_interruptible(void/* params in registers */);
 77 asmlinkage int__down_failed_trylock(void/* params in registers */);
 78 asmlinkage void__up_wakeup(void/* special register calling convention */);
 79
 80 asmlinkage void__down(struct semaphore * sem);
 81 asmlinkage int__down_interruptible(struct semaphore * sem);
 82 asmlinkage int__down_trylock(struct semaphore * sem);
 83 asmlinkage void__up(struct semaphore * sem);
 84
 85 extern spinlock_t semaphore_wake_lock;
 86
 87 extern __inline__ voiddown(struct semaphore * sem)
 88 {
 89 #if WAITQUEUE_DEBUG
 90 CHECK_MAGIC(sem->__magic);
 91 #endif
 92
 93 if(atomic_dec_return(&sem->count) <0)
 94 __down(sem);
 95 }
 96
 97 extern __inline__ intdown_interruptible(struct semaphore * sem)
 98 {
 99 int ret =0;
 100 #if WAITQUEUE_DEBUG
 101 CHECK_MAGIC(sem->__magic);
 102 #endif
 103
 104 if(atomic_dec_return(&sem->count) <0)
 105  ret =__down_interruptible(sem);
 106 return ret;
 107 }
 108
 109 extern __inline__ intdown_trylock(struct semaphore * sem)
 110 {
 111 int ret =0;
 112 #if WAITQUEUE_DEBUG
 113 CHECK_MAGIC(sem->__magic);
 114 #endif
 115
 116 if(atomic_dec_return(&sem->count) <0)
 117  ret =__down_trylock(sem);
 118 return ret;
 119 }
 120
 121 /*
 122  * Note! This is subtle. We jump to wake people up only if
 123  * the semaphore was negative (== somebody was waiting on it).
 124  */
 125 extern __inline__ voidup(struct semaphore * sem)
 126 {
 127 #if WAITQUEUE_DEBUG
 128 CHECK_MAGIC(sem->__magic);
 129 #endif
 130 if(atomic_inc_return(&sem->count) <=0)
 131 __up(sem);
 132 }
 133
 134 #endif/* __ASM_SH_SEMAPHORE_H */