include/asm-arm26/atomic.h

   1 /*
   2  *  linux/include/asm-arm26/atomic.h
   3  *
   4  *  Copyright (c) 1996 Russell King.
   5  *  Modified for arm26 by Ian Molton
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  *  Changelog:
  12  *   25-11-2004 IM      Updated for 2.6.9
  13  *   27-06-1996 RMK     Created
  14  *   13-04-1997 RMK     Made functions atomic!
  15  *   07-12-1997 RMK     Upgraded for v2.1.
  16  *   26-08-1998 PJB     Added #ifdef __KERNEL__
  17  *
  18  *  FIXME - its probably worth seeing what these compile into...
  19  */
  20 #ifndef __ASM_ARM_ATOMIC_H
  21 #define __ASM_ARM_ATOMIC_H
  22
  23 #include <linux/config.h>
  24
  25 #ifdef CONFIG_SMP
  26 #error SMP is NOT supported
  27 #endif
  28
  29 typedef struct { volatile int counter; } atomic_t;
  30
  31 #define ATOMIC_INIT(i)  { (i) }
  32
  33 #ifdef __KERNEL__
  34 #include <asm/system.h>
  35
  36 #define atomic_read(v) ((v)->counter)
  37 #define atomic_set(v,i) (((v)->counter) = (i))
  38
  39 static inline int atomic_add_return(int i, atomic_t *v)
  40 {
  41         unsigned long flags;
  42         int val;
  43
  44         local_irq_save(flags);
  45         val = v->counter;
  46         v->counter = val += i;
  47         local_irq_restore(flags);
  48
  49         return val;
  50 }
  51
  52 static inline int atomic_sub_return(int i, atomic_t *v)
  53 {
  54         unsigned long flags;
  55         int val;
  56
  57         local_irq_save(flags);
  58         val = v->counter;
  59         v->counter = val -= i;
  60         local_irq_restore(flags);
  61
  62         return val;
  63 }
  64
  65 static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
  66 {
  67         unsigned long flags;
  68
  69         local_irq_save(flags);
  70         *addr &= ~mask;
  71         local_irq_restore(flags);
  72 }
  73
  74 #define atomic_add(i, v)        (void) atomic_add_return(i, v)
  75 #define atomic_inc(v)           (void) atomic_add_return(1, v)
  76 #define atomic_sub(i, v)        (void) atomic_sub_return(i, v)
  77 #define atomic_dec(v)           (void) atomic_sub_return(1, v)
  78
  79 #define atomic_inc_and_test(v)  (atomic_add_return(1, v) == 0)
  80 #define atomic_dec_and_test(v)  (atomic_sub_return(1, v) == 0)
  81 #define atomic_inc_return(v)    (atomic_add_return(1, v))
  82 #define atomic_dec_return(v)    (atomic_sub_return(1, v))
  83
  84 #define atomic_add_negative(i,v) (atomic_add_return(i, v) < 0)
  85
  86 /* Atomic operations are already serializing on ARM26 */
  87 #define smp_mb__before_atomic_dec()     barrier()
  88 #define smp_mb__after_atomic_dec()      barrier()
  89 #define smp_mb__before_atomic_inc()     barrier()
  90 #define smp_mb__after_atomic_inc()      barrier()
  91
  92 #endif
  93 #endif