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 <asm/system.h>
  18
  19 /*
  20  * To get proper branch prediction for the main line, we must branch
  21  * forward to code at the end of this object's .text section, then
  22  * branch back to restart the operation.
  23  */
  24
  25 static __inline__ void atomic_add(int i, atomic_t * v)
  26 {
  27         unsigned long flags;
  28
  29         local_irq_save(flags);
  30         *(long *)v += i;
  31         local_irq_restore(flags);
  32 }
  33
  34 static __inline__ void atomic_sub(int i, atomic_t *v)
  35 {
  36         unsigned long flags;
  37
  38         local_irq_save(flags);
  39         *(long *)v -= i;
  40         local_irq_restore(flags);
  41 }
  42
  43 static __inline__ int atomic_add_return(int i, atomic_t * v)
  44 {
  45         unsigned long temp, flags;
  46
  47         local_irq_save(flags);
  48         temp = *(long *)v;
  49         temp += i;
  50         *(long *)v = temp;
  51         local_irq_restore(flags);
  52
  53         return temp;
  54 }
  55
  56 #define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
  57
  58 static __inline__ int atomic_sub_return(int i, atomic_t * v)
  59 {
  60         unsigned long temp, flags;
  61
  62         local_irq_save(flags);
  63         temp = *(long *)v;
  64         temp -= i;
  65         *(long *)v = temp;
  66         local_irq_restore(flags);
  67
  68         return temp;
  69 }
  70
  71 #define atomic_dec_return(v) atomic_sub_return(1,(v))
  72 #define atomic_inc_return(v) atomic_add_return(1,(v))
  73
  74 /*
  75  * atomic_inc_and_test - increment and test
  76  * @v: pointer of type atomic_t
  77  *
  78  * Atomically increments @v by 1
  79  * and returns true if the result is zero, or false for all
  80  * other cases.
  81  */
  82 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
  83
  84 #define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
  85 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
  86
  87 #define atomic_inc(v) atomic_add(1,(v))
  88 #define atomic_dec(v) atomic_sub(1,(v))
  89
  90 static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
  91 {
  92         int ret;
  93         unsigned long flags;
  94
  95         local_irq_save(flags);
  96         ret = v->counter;
  97         if (likely(ret == old))
  98                 v->counter = new;
  99         local_irq_restore(flags);
 100
 101         return ret;
 102 }
 103
 104 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 105
 106 static inline int atomic_add_unless(atomic_t *v, int a, int u)
 107 {
 108         int ret;
 109         unsigned long flags;
 110
 111         local_irq_save(flags);
 112         ret = v->counter;
 113         if (ret != u)
 114                 v->counter += a;
 115         local_irq_restore(flags);
 116
 117         return ret != u;
 118 }
 119 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 120
 121 static __inline__ void atomic_clear_mask(unsigned int mask, atomic_t *v)
 122 {
 123         unsigned long flags;
 124
 125         local_irq_save(flags);
 126         *(long *)v &= ~mask;
 127         local_irq_restore(flags);
 128 }
 129
 130 static __inline__ void atomic_set_mask(unsigned int mask, atomic_t *v)
 131 {
 132         unsigned long flags;
 133
 134         local_irq_save(flags);
 135         *(long *)v |= mask;
 136         local_irq_restore(flags);
 137 }
 138
 139 /* Atomic operations are already serializing on SH */
 140 #define smp_mb__before_atomic_dec()     barrier()
 141 #define smp_mb__after_atomic_dec()      barrier()
 142 #define smp_mb__before_atomic_inc()     barrier()
 143 #define smp_mb__after_atomic_inc()      barrier()
 144
 145 #include <asm-generic/atomic.h>
 146 #endif /* __ASM_SH_ATOMIC_H */