arch/powerpc/include/asm/atomic.h

   1 /*
   2  * PowerPC atomic operations
   3  */
   4
   5 #ifndef _ASM_PPC_ATOMIC_H_
   6 #define _ASM_PPC_ATOMIC_H_
   7
   8 #ifdef CONFIG_SMP
   9 typedef struct { volatile int counter; } atomic_t;
  10 #else
  11 typedef struct { int counter; } atomic_t;
  12 #endif
  13
  14 #define ATOMIC_INIT(i)  { (i) }
  15
  16 #define atomic_read(v)          ((v)->counter)
  17 #define atomic_set(v,i)         (((v)->counter) = (i))
  18
  19 extern void atomic_clear_mask(unsigned long mask, unsigned long *addr);
  20 extern void atomic_set_mask(unsigned long mask, unsigned long *addr);
  21
  22 static __inline__ int atomic_add_return(int a, atomic_t *v)
  23 {
  24         int t;
  25
  26         __asm__ __volatile__("\n\
  27 1:      lwarx   %0,0,%3\n\
  28         add     %0,%2,%0\n\
  29         stwcx.  %0,0,%3\n\
  30         bne-    1b"
  31         : "=&r" (t), "=m" (*v)
  32         : "r" (a), "r" (v), "m" (*v)
  33         : "cc");
  34
  35         return t;
  36 }
  37
  38 static __inline__ int atomic_sub_return(int a, atomic_t *v)
  39 {
  40         int t;
  41
  42         __asm__ __volatile__("\n\
  43 1:      lwarx   %0,0,%3\n\
  44         subf    %0,%2,%0\n\
  45         stwcx.  %0,0,%3\n\
  46         bne-    1b"
  47         : "=&r" (t), "=m" (*v)
  48         : "r" (a), "r" (v), "m" (*v)
  49         : "cc");
  50
  51         return t;
  52 }
  53
  54 static __inline__ int atomic_inc_return(atomic_t *v)
  55 {
  56         int t;
  57
  58         __asm__ __volatile__("\n\
  59 1:      lwarx   %0,0,%2\n\
  60         addic   %0,%0,1\n\
  61         stwcx.  %0,0,%2\n\
  62         bne-    1b"
  63         : "=&r" (t), "=m" (*v)
  64         : "r" (v), "m" (*v)
  65         : "cc");
  66
  67         return t;
  68 }
  69
  70 static __inline__ int atomic_dec_return(atomic_t *v)
  71 {
  72         int t;
  73
  74         __asm__ __volatile__("\n\
  75 1:      lwarx   %0,0,%2\n\
  76         addic   %0,%0,-1\n\
  77         stwcx.  %0,0,%2\n\
  78         bne     1b"
  79         : "=&r" (t), "=m" (*v)
  80         : "r" (v), "m" (*v)
  81         : "cc");
  82
  83         return t;
  84 }
  85
  86 #define atomic_add(a, v)                ((void) atomic_add_return((a), (v)))
  87 #define atomic_sub(a, v)                ((void) atomic_sub_return((a), (v)))
  88 #define atomic_sub_and_test(a, v)       (atomic_sub_return((a), (v)) == 0)
  89 #define atomic_inc(v)                   ((void) atomic_inc_return((v)))
  90 #define atomic_dec(v)                   ((void) atomic_dec_return((v)))
  91 #define atomic_dec_and_test(v)          (atomic_dec_return((v)) == 0)
  92
  93 #endif /* _ASM_PPC_ATOMIC_H_ */