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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 | /* semaphore.h: semaphores for the FR-V * * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #ifndef _ASM_SEMAPHORE_H #define _ASM_SEMAPHORE_H #define RW_LOCK_BIAS 0x01000000 #ifndef __ASSEMBLY__ #include <linux/linkage.h> #include <linux/wait.h> #include <linux/spinlock.h> #include <linux/rwsem.h> #define SEMAPHORE_DEBUG WAITQUEUE_DEBUG /* * the semaphore definition * - if counter is >0 then there are tokens available on the semaphore for down to collect * - if counter is <=0 then there are no spare tokens, and anyone that wants one must wait * - if wait_list is not empty, then there are processes waiting for the semaphore */ struct semaphore { unsigned counter; spinlock_t wait_lock; struct list_head wait_list; #if SEMAPHORE_DEBUG unsigned __magic; #endif }; #if SEMAPHORE_DEBUG # define __SEM_DEBUG_INIT(name) , (long)&(name).__magic #else # define __SEM_DEBUG_INIT(name) #endif #define __SEMAPHORE_INITIALIZER(name,count) \ { count, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __SEM_DEBUG_INIT(name) } #define __MUTEX_INITIALIZER(name) \ __SEMAPHORE_INITIALIZER(name,1) #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); } 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); } extern void __down(struct semaphore *sem, unsigned long flags); extern int __down_interruptible(struct semaphore *sem, unsigned long flags); extern void __up(struct semaphore *sem); static inline void down(struct semaphore *sem) { unsigned long flags; #if SEMAPHORE_DEBUG CHECK_MAGIC(sem->__magic); #endif spin_lock_irqsave(&sem->wait_lock, flags); if (likely(sem->counter > 0)) { sem->counter--; spin_unlock_irqrestore(&sem->wait_lock, flags); } else { __down(sem, flags); } } static inline int down_interruptible(struct semaphore *sem) { unsigned long flags; int ret = 0; #if SEMAPHORE_DEBUG CHECK_MAGIC(sem->__magic); #endif spin_lock_irqsave(&sem->wait_lock, flags); if (likely(sem->counter > 0)) { sem->counter--; spin_unlock_irqrestore(&sem->wait_lock, flags); } else { ret = __down_interruptible(sem, flags); } return ret; } /* * non-blockingly attempt to down() a semaphore. * - returns zero if we acquired it */ static inline int down_trylock(struct semaphore *sem) { unsigned long flags; int success = 0; #if SEMAPHORE_DEBUG CHECK_MAGIC(sem->__magic); #endif spin_lock_irqsave(&sem->wait_lock, flags); if (sem->counter > 0) { sem->counter--; success = 1; } spin_unlock_irqrestore(&sem->wait_lock, flags); return !success; } static inline void up(struct semaphore *sem) { unsigned long flags; #if SEMAPHORE_DEBUG CHECK_MAGIC(sem->__magic); #endif spin_lock_irqsave(&sem->wait_lock, flags); if (!list_empty(&sem->wait_list)) __up(sem); else sem->counter++; spin_unlock_irqrestore(&sem->wait_lock, flags); } static inline int sem_getcount(struct semaphore *sem) { return sem->counter; } #endif /* __ASSEMBLY__ */ #endif |