arch/sh/include/asm/atomic.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_SH_ATOMIC_H
   3 #define __ASM_SH_ATOMIC_H
   4
   5 #if defined(CONFIG_CPU_J2)
   6
   7 #include <asm-generic/atomic.h>
   8
   9 #else
  10
  11 /*
  12  * Atomic operations that C can't guarantee us.  Useful for
  13  * resource counting etc..
  14  *
  15  */
  16
  17 #include <linux/compiler.h>
  18 #include <linux/types.h>
  19 #include <asm/cmpxchg.h>
  20 #include <asm/barrier.h>
  21
  22 #define ATOMIC_INIT(i)  { (i) }
  23
  24 #define atomic_read(v)          READ_ONCE((v)->counter)
  25 #define atomic_set(v,i)         WRITE_ONCE((v)->counter, (i))
  26
  27 #if defined(CONFIG_GUSA_RB)
  28 #include <asm/atomic-grb.h>
  29 #elif defined(CONFIG_CPU_SH4A)
  30 #include <asm/atomic-llsc.h>
  31 #else
  32 #include <asm/atomic-irq.h>
  33 #endif
  34
  35 #define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
  36 #define atomic_dec_return(v)            atomic_sub_return(1, (v))
  37 #define atomic_inc_return(v)            atomic_add_return(1, (v))
  38 #define atomic_inc_and_test(v)          (atomic_inc_return(v) == 0)
  39 #define atomic_sub_and_test(i,v)        (atomic_sub_return((i), (v)) == 0)
  40 #define atomic_dec_and_test(v)          (atomic_sub_return(1, (v)) == 0)
  41
  42 #define atomic_inc(v)                   atomic_add(1, (v))
  43 #define atomic_dec(v)                   atomic_sub(1, (v))
  44
  45 #define atomic_xchg(v, new)             (xchg(&((v)->counter), new))
  46 #define atomic_cmpxchg(v, o, n)         (cmpxchg(&((v)->counter), (o), (n)))
  47
  48 /**
  49  * __atomic_add_unless - add unless the number is a given value
  50  * @v: pointer of type atomic_t
  51  * @a: the amount to add to v...
  52  * @u: ...unless v is equal to u.
  53  *
  54  * Atomically adds @a to @v, so long as it was not @u.
  55  * Returns the old value of @v.
  56  */
  57 static inline int __atomic_add_unless(atomic_t *v, int a, int u)
  58 {
  59         int c, old;
  60         c = atomic_read(v);
  61         for (;;) {
  62                 if (unlikely(c == (u)))
  63                         break;
  64                 old = atomic_cmpxchg((v), c, c + (a));
  65                 if (likely(old == c))
  66                         break;
  67                 c = old;
  68         }
  69
  70         return c;
  71 }
  72
  73 #endif /* CONFIG_CPU_J2 */
  74
  75 #endif /* __ASM_SH_ATOMIC_H */