arch/sparc/lib/atomic32.c

   1 /*
   2  * atomic32.c: 32-bit atomic_t implementation
   3  *
   4  * Copyright (C) 2004 Keith M Wesolowski
   5  * Copyright (C) 2007 Kyle McMartin
   6  *
   7  * Based on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf
   8  */
   9
  10 #include <linux/atomic.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/module.h>
  13
  14 #ifdef CONFIG_SMP
  15 #define ATOMIC_HASH_SIZE        4
  16 #define ATOMIC_HASH(a)  (&__atomic_hash[(((unsigned long)a)>>8) & (ATOMIC_HASH_SIZE-1)])
  17
  18 spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] = {
  19         [0 ... (ATOMIC_HASH_SIZE-1)] = __SPIN_LOCK_UNLOCKED(__atomic_hash)
  20 };
  21
  22 #else /* SMP */
  23
  24 static DEFINE_SPINLOCK(dummy);
  25 #define ATOMIC_HASH_SIZE        1
  26 #define ATOMIC_HASH(a)          (&dummy)
  27
  28 #endif /* SMP */
  29
  30 #define ATOMIC_OP_RETURN(op, c_op)                                      \
  31 int atomic_##op##_return(int i, atomic_t *v)                            \
  32 {                                                                       \
  33         int ret;                                                        \
  34         unsigned long flags;                                            \
  35         spin_lock_irqsave(ATOMIC_HASH(v), flags);                       \
  36                                                                         \
  37         ret = (v->counter c_op i);                                      \
  38                                                                         \
  39         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);                  \
  40         return ret;                                                     \
  41 }                                                                       \
  42 EXPORT_SYMBOL(atomic_##op##_return);
  43
  44 #define ATOMIC_OP(op, c_op)                                             \
  45 void atomic_##op(int i, atomic_t *v)                                    \
  46 {                                                                       \
  47         unsigned long flags;                                            \
  48         spin_lock_irqsave(ATOMIC_HASH(v), flags);                       \
  49                                                                         \
  50         v->counter c_op i;                                              \
  51                                                                         \
  52         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);                  \
  53 }                                                                       \
  54 EXPORT_SYMBOL(atomic_##op);
  55
  56 ATOMIC_OP_RETURN(add, +=)
  57 ATOMIC_OP(and, &=)
  58 ATOMIC_OP(or, |=)
  59 ATOMIC_OP(xor, ^=)
  60
  61 #undef ATOMIC_OP_RETURN
  62 #undef ATOMIC_OP
  63
  64 int atomic_xchg(atomic_t *v, int new)
  65 {
  66         int ret;
  67         unsigned long flags;
  68
  69         spin_lock_irqsave(ATOMIC_HASH(v), flags);
  70         ret = v->counter;
  71         v->counter = new;
  72         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
  73         return ret;
  74 }
  75 EXPORT_SYMBOL(atomic_xchg);
  76
  77 int atomic_cmpxchg(atomic_t *v, int old, int new)
  78 {
  79         int ret;
  80         unsigned long flags;
  81
  82         spin_lock_irqsave(ATOMIC_HASH(v), flags);
  83         ret = v->counter;
  84         if (likely(ret == old))
  85                 v->counter = new;
  86
  87         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
  88         return ret;
  89 }
  90 EXPORT_SYMBOL(atomic_cmpxchg);
  91
  92 int __atomic_add_unless(atomic_t *v, int a, int u)
  93 {
  94         int ret;
  95         unsigned long flags;
  96
  97         spin_lock_irqsave(ATOMIC_HASH(v), flags);
  98         ret = v->counter;
  99         if (ret != u)
 100                 v->counter += a;
 101         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
 102         return ret;
 103 }
 104 EXPORT_SYMBOL(__atomic_add_unless);
 105
 106 /* Atomic operations are already serializing */
 107 void atomic_set(atomic_t *v, int i)
 108 {
 109         unsigned long flags;
 110
 111         spin_lock_irqsave(ATOMIC_HASH(v), flags);
 112         v->counter = i;
 113         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
 114 }
 115 EXPORT_SYMBOL(atomic_set);
 116
 117 unsigned long ___set_bit(unsigned long *addr, unsigned long mask)
 118 {
 119         unsigned long old, flags;
 120
 121         spin_lock_irqsave(ATOMIC_HASH(addr), flags);
 122         old = *addr;
 123         *addr = old | mask;
 124         spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
 125
 126         return old & mask;
 127 }
 128 EXPORT_SYMBOL(___set_bit);
 129
 130 unsigned long ___clear_bit(unsigned long *addr, unsigned long mask)
 131 {
 132         unsigned long old, flags;
 133
 134         spin_lock_irqsave(ATOMIC_HASH(addr), flags);
 135         old = *addr;
 136         *addr = old & ~mask;
 137         spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
 138
 139         return old & mask;
 140 }
 141 EXPORT_SYMBOL(___clear_bit);
 142
 143 unsigned long ___change_bit(unsigned long *addr, unsigned long mask)
 144 {
 145         unsigned long old, flags;
 146
 147         spin_lock_irqsave(ATOMIC_HASH(addr), flags);
 148         old = *addr;
 149         *addr = old ^ mask;
 150         spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
 151
 152         return old & mask;
 153 }
 154 EXPORT_SYMBOL(___change_bit);
 155
 156 unsigned long __cmpxchg_u32(volatile u32 *ptr, u32 old, u32 new)
 157 {
 158         unsigned long flags;
 159         u32 prev;
 160
 161         spin_lock_irqsave(ATOMIC_HASH(ptr), flags);
 162         if ((prev = *ptr) == old)
 163                 *ptr = new;
 164         spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);
 165
 166         return (unsigned long)prev;
 167 }
 168 EXPORT_SYMBOL(__cmpxchg_u32);
 169
 170 unsigned long __xchg_u32(volatile u32 *ptr, u32 new)
 171 {
 172         unsigned long flags;
 173         u32 prev;
 174
 175         spin_lock_irqsave(ATOMIC_HASH(ptr), flags);
 176         prev = *ptr;
 177         *ptr = new;
 178         spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);
 179
 180         return (unsigned long)prev;
 181 }
 182 EXPORT_SYMBOL(__xchg_u32);