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

   1#ifndef __ASM_SH_ATOMIC_H
   2#define __ASM_SH_ATOMIC_H
   3
   4#if defined(CONFIG_CPU_J2)
   5
   6#include <asm-generic/atomic.h>
   7
   8#else
   9
  10/*
  11 * Atomic operations that C can't guarantee us.  Useful for
  12 * resource counting etc..
  13 *
  14 */
  15
  16#include <linux/compiler.h>
  17#include <linux/types.h>
  18#include <asm/cmpxchg.h>
  19#include <asm/barrier.h>
  20
  21#define ATOMIC_INIT(i)  { (i) }
  22
  23#define atomic_read(v)          READ_ONCE((v)->counter)
  24#define atomic_set(v,i)         WRITE_ONCE((v)->counter, (i))
  25
  26#if defined(CONFIG_GUSA_RB)
  27#include <asm/atomic-grb.h>
  28#elif defined(CONFIG_CPU_SH4A)
  29#include <asm/atomic-llsc.h>
  30#else
  31#include <asm/atomic-irq.h>
  32#endif
  33
  34#define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
  35#define atomic_dec_return(v)            atomic_sub_return(1, (v))
  36#define atomic_inc_return(v)            atomic_add_return(1, (v))
  37#define atomic_inc_and_test(v)          (atomic_inc_return(v) == 0)
  38#define atomic_sub_and_test(i,v)        (atomic_sub_return((i), (v)) == 0)
  39#define atomic_dec_and_test(v)          (atomic_sub_return(1, (v)) == 0)
  40
  41#define atomic_inc(v)                   atomic_add(1, (v))
  42#define atomic_dec(v)                   atomic_sub(1, (v))
  43
  44#define atomic_xchg(v, new)             (xchg(&((v)->counter), new))
  45#define atomic_cmpxchg(v, o, n)         (cmpxchg(&((v)->counter), (o), (n)))
  46
  47/**
  48 * __atomic_add_unless - add unless the number is a given value
  49 * @v: pointer of type atomic_t
  50 * @a: the amount to add to v...
  51 * @u: ...unless v is equal to u.
  52 *
  53 * Atomically adds @a to @v, so long as it was not @u.
  54 * Returns the old value of @v.
  55 */
  56static inline int __atomic_add_unless(atomic_t *v, int a, int u)
  57{
  58        int c, old;
  59        c = atomic_read(v);
  60        for (;;) {
  61                if (unlikely(c == (u)))
  62                        break;
  63                old = atomic_cmpxchg((v), c, c + (a));
  64                if (likely(old == c))
  65                        break;
  66                c = old;
  67        }
  68
  69        return c;
  70}
  71
  72#endif /* CONFIG_CPU_J2 */
  73
  74#endif /* __ASM_SH_ATOMIC_H */
  75