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 __MUTEX_INITIALIZER(name) \
  36         __SEMAPHORE_INITIALIZER(name,1)
  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 /*
  47  *      *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
  48  *
  49  * i'd rather use the more flexible initialization above, but sadly
  50  * GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well.
  51  */
  52         atomic_set(&sem->count, val);
  53         sem->sleepers = 0;
  54         init_waitqueue_head(&sem->wait);
  55 }
  56
  57 static inline void init_MUTEX (struct semaphore *sem)
  58 {
  59         sema_init(sem, 1);
  60 }
  61
  62 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
  63 {
  64         sema_init(sem, 0);
  65 }
  66
  67 asmlinkage void __down_failed(void /* special register calling convention */);
  68 asmlinkage int  __down_failed_interruptible(void  /* params in registers */);
  69 asmlinkage int  __down_failed_trylock(void  /* params in registers */);
  70 asmlinkage void __up_wakeup(void /* special register calling convention */);
  71
  72 asmlinkage void __down(struct semaphore * sem);
  73 asmlinkage int  __down_interruptible(struct semaphore * sem);
  74 asmlinkage int  __down_trylock(struct semaphore * sem);
  75 asmlinkage void __up(struct semaphore * sem);
  76
  77 /*
  78  * Atomically decrement the semaphore's count.  If it goes negative,
  79  * block the calling thread in the TASK_UNINTERRUPTIBLE state.
  80  */
  81 static inline void down(struct semaphore * sem)
  82 {
  83         unsigned long flags;
  84         long count;
  85
  86         might_sleep();
  87         local_irq_save(flags);
  88         __asm__ __volatile__ (
  89                 "# down                         \n\t"
  90                 DCACHE_CLEAR("%0", "r4", "%1")
  91                 M32R_LOCK" %0, @%1;             \n\t"
  92                 "addi   %0, #-1;                \n\t"
  93                 M32R_UNLOCK" %0, @%1;           \n\t"
  94                 : "=&r" (count)
  95                 : "r" (&sem->count)
  96                 : "memory"
  97 #ifdef CONFIG_CHIP_M32700_TS1
  98                 , "r4"
  99 #endif  /* CONFIG_CHIP_M32700_TS1 */
 100         );
 101         local_irq_restore(flags);
 102
 103         if (unlikely(count < 0))
 104                 __down(sem);
 105 }
 106
 107 /*
 108  * Interruptible try to acquire a semaphore.  If we obtained
 109  * it, return zero.  If we were interrupted, returns -EINTR
 110  */
 111 static inline int down_interruptible(struct semaphore * sem)
 112 {
 113         unsigned long flags;
 114         long count;
 115         int result = 0;
 116
 117         might_sleep();
 118         local_irq_save(flags);
 119         __asm__ __volatile__ (
 120                 "# down_interruptible           \n\t"
 121                 DCACHE_CLEAR("%0", "r4", "%1")
 122                 M32R_LOCK" %0, @%1;             \n\t"
 123                 "addi   %0, #-1;                \n\t"
 124                 M32R_UNLOCK" %0, @%1;           \n\t"
 125                 : "=&r" (count)
 126                 : "r" (&sem->count)
 127                 : "memory"
 128 #ifdef CONFIG_CHIP_M32700_TS1
 129                 , "r4"
 130 #endif  /* CONFIG_CHIP_M32700_TS1 */
 131         );
 132         local_irq_restore(flags);
 133
 134         if (unlikely(count < 0))
 135                 result = __down_interruptible(sem);
 136
 137         return result;
 138 }
 139
 140 /*
 141  * Non-blockingly attempt to down() a semaphore.
 142  * Returns zero if we acquired it
 143  */
 144 static inline int down_trylock(struct semaphore * sem)
 145 {
 146         unsigned long flags;
 147         long count;
 148         int result = 0;
 149
 150         local_irq_save(flags);
 151         __asm__ __volatile__ (
 152                 "# down_trylock                 \n\t"
 153                 DCACHE_CLEAR("%0", "r4", "%1")
 154                 M32R_LOCK" %0, @%1;             \n\t"
 155                 "addi   %0, #-1;                \n\t"
 156                 M32R_UNLOCK" %0, @%1;           \n\t"
 157                 : "=&r" (count)
 158                 : "r" (&sem->count)
 159                 : "memory"
 160 #ifdef CONFIG_CHIP_M32700_TS1
 161                 , "r4"
 162 #endif  /* CONFIG_CHIP_M32700_TS1 */
 163         );
 164         local_irq_restore(flags);
 165
 166         if (unlikely(count < 0))
 167                 result = __down_trylock(sem);
 168
 169         return result;
 170 }
 171
 172 /*
 173  * Note! This is subtle. We jump to wake people up only if
 174  * the semaphore was negative (== somebody was waiting on it).
 175  * The default case (no contention) will result in NO
 176  * jumps for both down() and up().
 177  */
 178 static inline void up(struct semaphore * sem)
 179 {
 180         unsigned long flags;
 181         long count;
 182
 183         local_irq_save(flags);
 184         __asm__ __volatile__ (
 185                 "# up                           \n\t"
 186                 DCACHE_CLEAR("%0", "r4", "%1")
 187                 M32R_LOCK" %0, @%1;             \n\t"
 188                 "addi   %0, #1;                 \n\t"
 189                 M32R_UNLOCK" %0, @%1;           \n\t"
 190                 : "=&r" (count)
 191                 : "r" (&sem->count)
 192                 : "memory"
 193 #ifdef CONFIG_CHIP_M32700_TS1
 194                 , "r4"
 195 #endif  /* CONFIG_CHIP_M32700_TS1 */
 196         );
 197         local_irq_restore(flags);
 198
 199         if (unlikely(count <= 0))
 200                 __up(sem);
 201 }
 202
 203 #endif  /* __KERNEL__ */
 204
 205 #endif  /* _ASM_M32R_SEMAPHORE_H */