include/asm-sh/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 typedef 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
  50 static 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
  64 static 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 */