include/asm-m68knommu/semaphore.h

   1 #ifndef _M68K_SEMAPHORE_H
   2 #define _M68K_SEMAPHORE_H
   3
   4 #define RW_LOCK_BIAS             0x01000000
   5
   6 #ifndef __ASSEMBLY__
   7
   8 #include <linux/linkage.h>
   9 #include <linux/wait.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/rwsem.h>
  12
  13 #include <asm/system.h>
  14 #include <asm/atomic.h>
  15
  16 /*
  17  * Interrupt-safe semaphores..
  18  *
  19  * (C) Copyright 1996 Linus Torvalds
  20  *
  21  * m68k version by Andreas Schwab
  22  */
  23
  24
  25 struct semaphore {
  26         atomic_t count;
  27         atomic_t waking;
  28         wait_queue_head_t wait;
  29 };
  30
  31 #define __SEMAPHORE_INITIALIZER(name, n)                                \
  32 {                                                                       \
  33         .count          = ATOMIC_INIT(n),                               \
  34         .waking         = ATOMIC_INIT(0),                               \
  35         .wait           = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)    \
  36 }
  37
  38 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
  39         struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
  40
  41 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
  42 #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
  43
  44 static inline void sema_init (struct semaphore *sem, int val)
  45 {
  46         *sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
  47 }
  48
  49 static inline void init_MUTEX (struct semaphore *sem)
  50 {
  51         sema_init(sem, 1);
  52 }
  53
  54 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
  55 {
  56         sema_init(sem, 0);
  57 }
  58
  59 asmlinkage void __down_failed(void /* special register calling convention */);
  60 asmlinkage int  __down_failed_interruptible(void  /* params in registers */);
  61 asmlinkage int  __down_failed_trylock(void  /* params in registers */);
  62 asmlinkage void __up_wakeup(void /* special register calling convention */);
  63
  64 asmlinkage void __down(struct semaphore * sem);
  65 asmlinkage int  __down_interruptible(struct semaphore * sem);
  66 asmlinkage int  __down_trylock(struct semaphore * sem);
  67 asmlinkage void __up(struct semaphore * sem);
  68
  69 extern spinlock_t semaphore_wake_lock;
  70
  71 /*
  72  * This is ugly, but we want the default case to fall through.
  73  * "down_failed" is a special asm handler that calls the C
  74  * routine that actually waits. See arch/m68k/lib/semaphore.S
  75  */
  76 static inline void down(struct semaphore * sem)
  77 {
  78         might_sleep();
  79         __asm__ __volatile__(
  80                 "| atomic down operation\n\t"
  81                 "movel  %0, %%a1\n\t"
  82                 "lea    %%pc@(1f), %%a0\n\t"
  83                 "subql  #1, %%a1@\n\t"
  84                 "jmi __down_failed\n"
  85                 "1:"
  86                 : /* no outputs */
  87                 : "g" (sem)
  88                 : "cc", "%a0", "%a1", "memory");
  89 }
  90
  91 static inline int down_interruptible(struct semaphore * sem)
  92 {
  93         int ret;
  94
  95         might_sleep();
  96         __asm__ __volatile__(
  97                 "| atomic down operation\n\t"
  98                 "movel  %1, %%a1\n\t"
  99                 "lea    %%pc@(1f), %%a0\n\t"
 100                 "subql  #1, %%a1@\n\t"
 101                 "jmi __down_failed_interruptible\n\t"
 102                 "clrl   %%d0\n"
 103                 "1: movel       %%d0, %0\n"
 104                 : "=d" (ret)
 105                 : "g" (sem)
 106                 : "cc", "%d0", "%a0", "%a1", "memory");
 107         return(ret);
 108 }
 109
 110 static inline int down_trylock(struct semaphore * sem)
 111 {
 112         register struct semaphore *sem1 __asm__ ("%a1") = sem;
 113         register int result __asm__ ("%d0");
 114
 115         __asm__ __volatile__(
 116                 "| atomic down trylock operation\n\t"
 117                 "subql #1,%1@\n\t"
 118                 "jmi 2f\n\t"
 119                 "clrl %0\n"
 120                 "1:\n"
 121                 ".section .text.lock,\"ax\"\n"
 122                 ".even\n"
 123                 "2:\tpea 1b\n\t"
 124                 "jbra __down_failed_trylock\n"
 125                 ".previous"
 126                 : "=d" (result)
 127                 : "a" (sem1)
 128                 : "memory");
 129         return result;
 130 }
 131
 132 /*
 133  * Note! This is subtle. We jump to wake people up only if
 134  * the semaphore was negative (== somebody was waiting on it).
 135  * The default case (no contention) will result in NO
 136  * jumps for both down() and up().
 137  */
 138 static inline void up(struct semaphore * sem)
 139 {
 140         __asm__ __volatile__(
 141                 "| atomic up operation\n\t"
 142                 "movel  %0, %%a1\n\t"
 143                 "lea    %%pc@(1f), %%a0\n\t"
 144                 "addql  #1, %%a1@\n\t"
 145                 "jle __up_wakeup\n"
 146                 "1:"
 147                 : /* no outputs */
 148                 : "g" (sem)
 149                 : "cc", "%a0", "%a1", "memory");
 150 }
 151
 152 #endif /* __ASSEMBLY__ */
 153
 154 #endif