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#include <asm/barrier.h>
  14
  15#define ATOMIC_INIT(i)  { (i) }
  16
  17#define atomic_read(v)          ACCESS_ONCE((v)->counter)
  18#define atomic_set(v,i)         ((v)->counter = (i))
  19
  20#if defined(CONFIG_GUSA_RB)
  21#include <asm/atomic-grb.h>
  22#elif defined(CONFIG_CPU_SH4A)
  23#include <asm/atomic-llsc.h>
  24#else
  25#include <asm/atomic-irq.h>
  26#endif
  27
  28#define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
  29#define atomic_dec_return(v)            atomic_sub_return(1, (v))
  30#define atomic_inc_return(v)            atomic_add_return(1, (v))
  31#define atomic_inc_and_test(v)          (atomic_inc_return(v) == 0)
  32#define atomic_sub_and_test(i,v)        (atomic_sub_return((i), (v)) == 0)
  33#define atomic_dec_and_test(v)          (atomic_sub_return(1, (v)) == 0)
  34
  35#define atomic_inc(v)                   atomic_add(1, (v))
  36#define atomic_dec(v)                   atomic_sub(1, (v))
  37
  38#define atomic_xchg(v, new)             (xchg(&((v)->counter), new))
  39#define atomic_cmpxchg(v, o, n)         (cmpxchg(&((v)->counter), (o), (n)))
  40
  41/**
  42 * __atomic_add_unless - add unless the number is a given value
  43 * @v: pointer of type atomic_t
  44 * @a: the amount to add to v...
  45 * @u: ...unless v is equal to u.
  46 *
  47 * Atomically adds @a to @v, so long as it was not @u.
  48 * Returns the old value of @v.
  49 */
  50static inline int __atomic_add_unless(atomic_t *v, int a, int u)
  51{
  52        int c, old;
  53        c = atomic_read(v);
  54        for (;;) {
  55                if (unlikely(c == (u)))
  56                        break;
  57                old = atomic_cmpxchg((v), c, c + (a));
  58                if (likely(old == c))
  59                        break;
  60                c = old;
  61        }
  62
  63        return c;
  64}
  65
  66#endif /* __ASM_SH_ATOMIC_H */
  67