include/asm-m32r/semaphore.h

   1 #ifndef _ASM_M32R_SEMAPHORE_H
   2 #define _ASM_M32R_SEMAPHORE_H
   3
   4 #include <linux/linkage.h>
   5
   6 #ifdef __KERNEL__
   7
   8 /*
   9  * SMP- and interrupt-safe semaphores..
  10  *
  11  * Copyright (C) 1996  Linus Torvalds
  12  * Copyright (C) 2004  Hirokazu Takata <takata at linux-m32r.org>
  13  */
  14
  15 #include <linux/config.h>
  16 #include <linux/wait.h>
  17 #include <linux/rwsem.h>
  18 #include <asm/assembler.h>
  19 #include <asm/system.h>
  20 #include <asm/atomic.h>
  21
  22 struct semaphore {
  23         atomic_t count;
  24         int sleepers;
  25         wait_queue_head_t wait;
  26 };
  27
  28 #define __SEMAPHORE_INITIALIZER(name, n)                                \
  29 {                                                                       \
  30         .count          = ATOMIC_INIT(n),                               \
  31         .sleepers       = 0,                                            \
  32         .wait           = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)    \
  33 }
  34
  35 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
  36         struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
  37
  38 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
  39 #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
  40
  41 static inline void sema_init (struct semaphore *sem, int val)
  42 {
  43 /*
  44  *      *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
  45  *
  46  * i'd rather use the more flexible initialization above, but sadly
  47  * GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well.
  48  */
  49         atomic_set(&sem->count, val);
  50         sem->sleepers = 0;
  51         init_waitqueue_head(&sem->wait);
  52 }
  53
  54 static inline void init_MUTEX (struct semaphore *sem)
  55 {
  56         sema_init(sem, 1);
  57 }
  58
  59 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
  60 {
  61         sema_init(sem, 0);
  62 }
  63
  64 asmlinkage void __down_failed(void /* special register calling convention */);
  65 asmlinkage int  __down_failed_interruptible(void  /* params in registers */);
  66 asmlinkage int  __down_failed_trylock(void  /* params in registers */);
  67 asmlinkage void __up_wakeup(void /* special register calling convention */);
  68
  69 asmlinkage void __down(struct semaphore * sem);
  70 asmlinkage int  __down_interruptible(struct semaphore * sem);
  71 asmlinkage int  __down_trylock(struct semaphore * sem);
  72 asmlinkage void __up(struct semaphore * sem);
  73
  74 /*
  75  * Atomically decrement the semaphore's count.  If it goes negative,
  76  * block the calling thread in the TASK_UNINTERRUPTIBLE state.
  77  */
  78 static inline void down(struct semaphore * sem)
  79 {
  80         unsigned long flags;
  81         long count;
  82
  83         might_sleep();
  84         local_irq_save(flags);
  85         __asm__ __volatile__ (
  86                 "# down                         \n\t"
  87                 DCACHE_CLEAR("%0", "r4", "%1")
  88                 M32R_LOCK" %0, @%1;             \n\t"
  89                 "addi   %0, #-1;                \n\t"
  90                 M32R_UNLOCK" %0, @%1;           \n\t"
  91                 : "=&r" (count)
  92                 : "r" (&sem->count)
  93                 : "memory"
  94 #ifdef CONFIG_CHIP_M32700_TS1
  95                 , "r4"
  96 #endif  /* CONFIG_CHIP_M32700_TS1 */
  97         );
  98         local_irq_restore(flags);
  99
 100         if (unlikely(count < 0))
 101                 __down(sem);
 102 }
 103
 104 /*
 105  * Interruptible try to acquire a semaphore.  If we obtained
 106  * it, return zero.  If we were interrupted, returns -EINTR
 107  */
 108 static inline int down_interruptible(struct semaphore * sem)
 109 {
 110         unsigned long flags;
 111         long count;
 112         int result = 0;
 113
 114         might_sleep();
 115         local_irq_save(flags);
 116         __asm__ __volatile__ (
 117                 "# down_interruptible           \n\t"
 118                 DCACHE_CLEAR("%0", "r4", "%1")
 119                 M32R_LOCK" %0, @%1;             \n\t"
 120                 "addi   %0, #-1;                \n\t"
 121                 M32R_UNLOCK" %0, @%1;           \n\t"
 122                 : "=&r" (count)
 123                 : "r" (&sem->count)
 124                 : "memory"
 125 #ifdef CONFIG_CHIP_M32700_TS1
 126                 , "r4"
 127 #endif  /* CONFIG_CHIP_M32700_TS1 */
 128         );
 129         local_irq_restore(flags);
 130
 131         if (unlikely(count < 0))
 132                 result = __down_interruptible(sem);
 133
 134         return result;
 135 }
 136
 137 /*
 138  * Non-blockingly attempt to down() a semaphore.
 139  * Returns zero if we acquired it
 140  */
 141 static inline int down_trylock(struct semaphore * sem)
 142 {
 143         unsigned long flags;
 144         long count;
 145         int result = 0;
 146
 147         local_irq_save(flags);
 148         __asm__ __volatile__ (
 149                 "# down_trylock                 \n\t"
 150                 DCACHE_CLEAR("%0", "r4", "%1")
 151                 M32R_LOCK" %0, @%1;             \n\t"
 152                 "addi   %0, #-1;                \n\t"
 153                 M32R_UNLOCK" %0, @%1;           \n\t"
 154                 : "=&r" (count)
 155                 : "r" (&sem->count)
 156                 : "memory"
 157 #ifdef CONFIG_CHIP_M32700_TS1
 158                 , "r4"
 159 #endif  /* CONFIG_CHIP_M32700_TS1 */
 160         );
 161         local_irq_restore(flags);
 162
 163         if (unlikely(count < 0))
 164                 result = __down_trylock(sem);
 165
 166         return result;
 167 }
 168
 169 /*
 170  * Note! This is subtle. We jump to wake people up only if
 171  * the semaphore was negative (== somebody was waiting on it).
 172  * The default case (no contention) will result in NO
 173  * jumps for both down() and up().
 174  */
 175 static inline void up(struct semaphore * sem)
 176 {
 177         unsigned long flags;
 178         long count;
 179
 180         local_irq_save(flags);
 181         __asm__ __volatile__ (
 182                 "# up                           \n\t"
 183                 DCACHE_CLEAR("%0", "r4", "%1")
 184                 M32R_LOCK" %0, @%1;             \n\t"
 185                 "addi   %0, #1;                 \n\t"
 186                 M32R_UNLOCK" %0, @%1;           \n\t"
 187                 : "=&r" (count)
 188                 : "r" (&sem->count)
 189                 : "memory"
 190 #ifdef CONFIG_CHIP_M32700_TS1
 191                 , "r4"
 192 #endif  /* CONFIG_CHIP_M32700_TS1 */
 193         );
 194         local_irq_restore(flags);
 195
 196         if (unlikely(count <= 0))
 197                 __up(sem);
 198 }
 199
 200 #endif  /* __KERNEL__ */
 201
 202 #endif  /* _ASM_M32R_SEMAPHORE_H */