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
  10typedef struct { volatile int counter; } atomic_t;
  11
  12#define ATOMIC_INIT(i)  ( (atomic_t) { (i) } )
  13
  14#define atomic_read(v)          ((v)->counter)
  15#define atomic_set(v,i)         ((v)->counter = (i))
  16
  17#include <linux/compiler.h>
  18#include <asm/system.h>
  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
  30#define atomic_dec_return(v) atomic_sub_return(1,(v))
  31#define atomic_inc_return(v) atomic_add_return(1,(v))
  32
  33/*
  34 * atomic_inc_and_test - increment and test
  35 * @v: pointer of type atomic_t
  36 *
  37 * Atomically increments @v by 1
  38 * and returns true if the result is zero, or false for all
  39 * other cases.
  40 */
  41#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
  42
  43#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
  44#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
  45
  46#define atomic_inc(v) atomic_add(1,(v))
  47#define atomic_dec(v) atomic_sub(1,(v))
  48
  49#ifndef CONFIG_GUSA_RB
  50static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
  51{
  52        int ret;
  53        unsigned long flags;
  54
  55        local_irq_save(flags);
  56        ret = v->counter;
  57        if (likely(ret == old))
  58                v->counter = new;
  59        local_irq_restore(flags);
  60
  61        return ret;
  62}
  63
  64static inline int atomic_add_unless(atomic_t *v, int a, int u)
  65{
  66        int ret;
  67        unsigned long flags;
  68
  69        local_irq_save(flags);
  70        ret = v->counter;
  71        if (ret != u)
  72                v->counter += a;
  73        local_irq_restore(flags);
  74
  75        return ret != u;
  76}
  77#endif
  78
  79#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
  80#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
  81
  82/* Atomic operations are already serializing on SH */
  83#define smp_mb__before_atomic_dec()     barrier()
  84#define smp_mb__after_atomic_dec()      barrier()
  85#define smp_mb__before_atomic_inc()     barrier()
  86#define smp_mb__after_atomic_inc()      barrier()
  87
  88#include <asm-generic/atomic.h>
  89#endif /* __ASM_SH_ATOMIC_H */
  90