include/asm-m68k/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 #include <linux/stringify.h>
  13
  14 #include <asm/system.h>
  15 #include <asm/atomic.h>
  16
  17 /*
  18  * Interrupt-safe semaphores..
  19  *
  20  * (C) Copyright 1996 Linus Torvalds
  21  *
  22  * m68k version by Andreas Schwab
  23  */
  24
  25
  26 struct semaphore {
  27         atomic_t count;
  28         atomic_t waking;
  29         wait_queue_head_t wait;
  30 };
  31
  32 #define __SEMAPHORE_INITIALIZER(name, n)                                \
  33 {                                                                       \
  34         .count          = ATOMIC_INIT(n),                               \
  35         .waking         = ATOMIC_INIT(0),                               \
  36         .wait           = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)    \
  37 }
  38
  39 #define __MUTEX_INITIALIZER(name) \
  40         __SEMAPHORE_INITIALIZER(name,1)
  41
  42 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
  43         struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
  44
  45 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
  46 #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
  47
  48 static inline void sema_init(struct semaphore *sem, int val)
  49 {
  50         *sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
  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 asmlinkage void __down_failed(void /* special register calling convention */);
  64 asmlinkage int  __down_failed_interruptible(void  /* params in registers */);
  65 asmlinkage int  __down_failed_trylock(void  /* params in registers */);
  66 asmlinkage void __up_wakeup(void /* special register calling convention */);
  67
  68 asmlinkage void __down(struct semaphore * sem);
  69 asmlinkage int  __down_interruptible(struct semaphore * sem);
  70 asmlinkage int  __down_trylock(struct semaphore * sem);
  71 asmlinkage void __up(struct semaphore * sem);
  72
  73 /*
  74  * This is ugly, but we want the default case to fall through.
  75  * "down_failed" is a special asm handler that calls the C
  76  * routine that actually waits. See arch/m68k/lib/semaphore.S
  77  */
  78 static inline void down(struct semaphore *sem)
  79 {
  80         register struct semaphore *sem1 __asm__ ("%a1") = sem;
  81
  82         might_sleep();
  83         __asm__ __volatile__(
  84                 "| atomic down operation\n\t"
  85                 "subql #1,%0@\n\t"
  86                 "jmi 2f\n\t"
  87                 "1:\n"
  88                 LOCK_SECTION_START(".even\n\t")
  89                 "2:\tpea 1b\n\t"
  90                 "jbra __down_failed\n"
  91                 LOCK_SECTION_END
  92                 : /* no outputs */
  93                 : "a" (sem1)
  94                 : "memory");
  95 }
  96
  97 static inline int down_interruptible(struct semaphore *sem)
  98 {
  99         register struct semaphore *sem1 __asm__ ("%a1") = sem;
 100         register int result __asm__ ("%d0");
 101
 102         might_sleep();
 103         __asm__ __volatile__(
 104                 "| atomic interruptible down operation\n\t"
 105                 "subql #1,%1@\n\t"
 106                 "jmi 2f\n\t"
 107                 "clrl %0\n"
 108                 "1:\n"
 109                 LOCK_SECTION_START(".even\n\t")
 110                 "2:\tpea 1b\n\t"
 111                 "jbra __down_failed_interruptible\n"
 112                 LOCK_SECTION_END
 113                 : "=d" (result)
 114                 : "a" (sem1)
 115                 : "memory");
 116         return result;
 117 }
 118
 119 static inline int down_trylock(struct semaphore *sem)
 120 {
 121         register struct semaphore *sem1 __asm__ ("%a1") = sem;
 122         register int result __asm__ ("%d0");
 123
 124         __asm__ __volatile__(
 125                 "| atomic down trylock operation\n\t"
 126                 "subql #1,%1@\n\t"
 127                 "jmi 2f\n\t"
 128                 "clrl %0\n"
 129                 "1:\n"
 130                 LOCK_SECTION_START(".even\n\t")
 131                 "2:\tpea 1b\n\t"
 132                 "jbra __down_failed_trylock\n"
 133                 LOCK_SECTION_END
 134                 : "=d" (result)
 135                 : "a" (sem1)
 136                 : "memory");
 137         return result;
 138 }
 139
 140 /*
 141  * Note! This is subtle. We jump to wake people up only if
 142  * the semaphore was negative (== somebody was waiting on it).
 143  * The default case (no contention) will result in NO
 144  * jumps for both down() and up().
 145  */
 146 static inline void up(struct semaphore *sem)
 147 {
 148         register struct semaphore *sem1 __asm__ ("%a1") = sem;
 149
 150         __asm__ __volatile__(
 151                 "| atomic up operation\n\t"
 152                 "addql #1,%0@\n\t"
 153                 "jle 2f\n"
 154                 "1:\n"
 155                 LOCK_SECTION_START(".even\n\t")
 156                 "2:\t"
 157                 "pea 1b\n\t"
 158                 "jbra __up_wakeup\n"
 159                 LOCK_SECTION_END
 160                 : /* no outputs */
 161                 : "a" (sem1)
 162                 : "memory");
 163 }
 164
 165 #endif /* __ASSEMBLY__ */
 166
 167 #endif