LXR linux/arch/sh/include/asm/atomic.h

   1#ifndef __ASM_SH_ATOMIC_H
   2#define __ASM_SH_ATOMIC_H
   3
   4/*
   5 * Atomic operations that C can't guarantee us.  Useful for
   6 * resource counting etc..
   7 *
   8 */
   9
  10#include <linux/compiler.h>
  11#include <linux/types.h>
  12#include <asm/cmpxchg.h>
  13
  14#define ATOMIC_INIT(i)  { (i) }
  15
  16#define atomic_read(v)          (*(volatile int *)&(v)->counter)
  17#define atomic_set(v,i)         ((v)->counter = (i))
  18
  19#if defined(CONFIG_GUSA_RB)
  20#include <asm/atomic-grb.h>
  21#elif defined(CONFIG_CPU_SH4A)
  22#include <asm/atomic-llsc.h>
  23#else
  24#include <asm/atomic-irq.h>
  25#endif
  26
  27#define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
  28#define atomic_dec_return(v)            atomic_sub_return(1, (v))
  29#define atomic_inc_return(v)            atomic_add_return(1, (v))
  30#define atomic_inc_and_test(v)          (atomic_inc_return(v) == 0)
  31#define atomic_sub_and_test(i,v)        (atomic_sub_return((i), (v)) == 0)
  32#define atomic_dec_and_test(v)          (atomic_sub_return(1, (v)) == 0)
  33
  34#define atomic_inc(v)                   atomic_add(1, (v))
  35#define atomic_dec(v)                   atomic_sub(1, (v))
  36
  37#define atomic_xchg(v, new)             (xchg(&((v)->counter), new))
  38#define atomic_cmpxchg(v, o, n)         (cmpxchg(&((v)->counter), (o), (n)))
  39
  40/**
  41 * __atomic_add_unless - add unless the number is a given value
  42 * @v: pointer of type atomic_t
  43 * @a: the amount to add to v...
  44 * @u: ...unless v is equal to u.
  45 *
  46 * Atomically adds @a to @v, so long as it was not @u.
  47 * Returns the old value of @v.
  48 */
  49static inline int __atomic_add_unless(atomic_t *v, int a, int u)
  50{
  51        int c, old;
  52        c = atomic_read(v);
  53        for (;;) {
  54                if (unlikely(c == (u)))
  55                        break;
  56                old = atomic_cmpxchg((v), c, c + (a));
  57                if (likely(old == c))
  58                        break;
  59                c = old;
  60        }
  61
  62        return c;
  63}
  64
  65#define smp_mb__before_atomic_dec()     smp_mb()
  66#define smp_mb__after_atomic_dec()      smp_mb()
  67#define smp_mb__before_atomic_inc()     smp_mb()
  68#define smp_mb__after_atomic_inc()      smp_mb()
  69
  70#endif /* __ASM_SH_ATOMIC_H */
  71