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
  43 static inline void sema_init (struct semaphore *sem, int val)
  44 {
  45         *sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
  46 }
  47
  48 static inline void init_MUTEX (struct semaphore *sem)
  49 {
  50         sema_init(sem, 1);
  51 }
  52
  53 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
  54 {
  55         sema_init(sem, 0);
  56 }
  57
  58 asmlinkage void __down_failed(void /* special register calling convention */);
  59 asmlinkage int  __down_failed_interruptible(void  /* params in registers */);
  60 asmlinkage int  __down_failed_trylock(void  /* params in registers */);
  61 asmlinkage void __up_wakeup(void /* special register calling convention */);
  62
  63 asmlinkage void __down(struct semaphore * sem);
  64 asmlinkage int  __down_interruptible(struct semaphore * sem);
  65 asmlinkage int  __down_trylock(struct semaphore * sem);
  66 asmlinkage void __up(struct semaphore * sem);
  67
  68 extern spinlock_t semaphore_wake_lock;
  69
  70 /*
  71  * This is ugly, but we want the default case to fall through.
  72  * "down_failed" is a special asm handler that calls the C
  73  * routine that actually waits. See arch/m68k/lib/semaphore.S
  74  */
  75 static inline void down(struct semaphore * sem)
  76 {
  77         might_sleep();
  78         __asm__ __volatile__(
  79                 "| atomic down operation\n\t"
  80                 "movel  %0, %%a1\n\t"
  81                 "lea    %%pc@(1f), %%a0\n\t"
  82                 "subql  #1, %%a1@\n\t"
  83                 "jmi __down_failed\n"
  84                 "1:"
  85                 : /* no outputs */
  86                 : "g" (sem)
  87                 : "cc", "%a0", "%a1", "memory");
  88 }
  89
  90 static inline int down_interruptible(struct semaphore * sem)
  91 {
  92         int ret;
  93
  94         might_sleep();
  95         __asm__ __volatile__(
  96                 "| atomic down operation\n\t"
  97                 "movel  %1, %%a1\n\t"
  98                 "lea    %%pc@(1f), %%a0\n\t"
  99                 "subql  #1, %%a1@\n\t"
 100                 "jmi __down_failed_interruptible\n\t"
 101                 "clrl   %%d0\n"
 102                 "1: movel       %%d0, %0\n"
 103                 : "=d" (ret)
 104                 : "g" (sem)
 105                 : "cc", "%d0", "%a0", "%a1", "memory");
 106         return(ret);
 107 }
 108
 109 static inline int down_trylock(struct semaphore * sem)
 110 {
 111         register struct semaphore *sem1 __asm__ ("%a1") = sem;
 112         register int result __asm__ ("%d0");
 113
 114         __asm__ __volatile__(
 115                 "| atomic down trylock operation\n\t"
 116                 "subql #1,%1@\n\t"
 117                 "jmi 2f\n\t"
 118                 "clrl %0\n"
 119                 "1:\n"
 120                 ".section .text.lock,\"ax\"\n"
 121                 ".even\n"
 122                 "2:\tpea 1b\n\t"
 123                 "jbra __down_failed_trylock\n"
 124                 ".previous"
 125                 : "=d" (result)
 126                 : "a" (sem1)
 127                 : "memory");
 128         return result;
 129 }
 130
 131 /*
 132  * Note! This is subtle. We jump to wake people up only if
 133  * the semaphore was negative (== somebody was waiting on it).
 134  * The default case (no contention) will result in NO
 135  * jumps for both down() and up().
 136  */
 137 static inline void up(struct semaphore * sem)
 138 {
 139         __asm__ __volatile__(
 140                 "| atomic up operation\n\t"
 141                 "movel  %0, %%a1\n\t"
 142                 "lea    %%pc@(1f), %%a0\n\t"
 143                 "addql  #1, %%a1@\n\t"
 144                 "jle __up_wakeup\n"
 145                 "1:"
 146                 : /* no outputs */
 147                 : "g" (sem)
 148                 : "cc", "%a0", "%a1", "memory");
 149 }
 150
 151 #endif /* __ASSEMBLY__ */
 152
 153 #endif