include/asm-ppc/semaphore.h

   1 #ifndef _PPC_SEMAPHORE_H
   2 #define _PPC_SEMAPHORE_H
   3
   4 /*
   5  * Swiped from asm-sparc/semaphore.h and modified
   6  * -- Cort (cort@cs.nmt.edu)
   7  */
   8
   9 #ifdef __KERNEL__
  10
  11 #include <asm/atomic.h>
  12 #include <linux/wait.h>
  13
  14 struct semaphore {
  15         atomic_t count;
  16         atomic_t waking;
  17         wait_queue_head_t wait;
  18 #if WAITQUEUE_DEBUG
  19         long __magic;
  20 #endif
  21 };
  22
  23 #if WAITQUEUE_DEBUG
  24 # define __SEM_DEBUG_INIT(name) \
  25                 , (long)&(name).__magic
  26 #else
  27 # define __SEM_DEBUG_INIT(name)
  28 #endif
  29
  30 #define __SEMAPHORE_INITIALIZER(name,count) \
  31 { ATOMIC_INIT(count), ATOMIC_INIT(0), __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
  32         __SEM_DEBUG_INIT(name) }
  33
  34 #define __MUTEX_INITIALIZER(name) \
  35         __SEMAPHORE_INITIALIZER(name,1)
  36
  37 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
  38         struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
  39
  40 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
  41 #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
  42
  43 extern inline void sema_init (struct semaphore *sem, int val)
  44 {
  45         atomic_set(&sem->count, val);
  46         atomic_set(&sem->waking, 0);
  47         init_waitqueue_head(&sem->wait);
  48 #if WAITQUEUE_DEBUG
  49         sem->__magic = (long)&sem->__magic;
  50 #endif
  51 }
  52
  53 static inline void init_MUTEX (struct semaphore *sem)
  54 {
  55         sema_init(sem, 1);
  56 }
  57
  58 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
  59 {
  60         sema_init(sem, 0);
  61 }
  62
  63 extern void __down(struct semaphore * sem);
  64 extern int  __down_interruptible(struct semaphore * sem);
  65 extern int  __down_trylock(struct semaphore * sem);
  66 extern void __up(struct semaphore * sem);
  67
  68 extern inline void down(struct semaphore * sem)
  69 {
  70         if (atomic_dec_return(&sem->count) >= 0)
  71                 wmb();
  72         else
  73                 __down(sem);
  74 }
  75
  76 extern inline int down_interruptible(struct semaphore * sem)
  77 {
  78         int ret = 0;
  79
  80         if (atomic_dec_return(&sem->count) >= 0)
  81                 wmb();
  82         else
  83                 ret = __down_interruptible(sem);
  84         return ret;
  85 }
  86
  87 extern inline int down_trylock(struct semaphore * sem)
  88 {
  89         int ret = 0;
  90
  91         if (atomic_dec_return(&sem->count) >= 0)
  92                 wmb();
  93         else
  94                 ret = __down_trylock(sem);
  95         return ret;
  96 }
  97
  98 extern inline void up(struct semaphore * sem)
  99 {
 100         mb();
 101         if (atomic_inc_return(&sem->count) <= 0)
 102                 __up(sem);
 103 }
 104
 105 #endif /* __KERNEL__ */
 106
 107 #endif /* !(_PPC_SEMAPHORE_H) */