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_FETCH_OP(op, c_op)                                       \
  31 int atomic_fetch_##op(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;                                               \
  38         v->counter c_op i;                                              \
  39                                                                         \
  40         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);                  \
  41         return ret;                                                     \
  42 }                                                                       \
  43 EXPORT_SYMBOL(atomic_fetch_##op);
  44
  45 #define ATOMIC_OP_RETURN(op, c_op)                                      \
  46 int atomic_##op##_return(int i, atomic_t *v)                            \
  47 {                                                                       \
  48         int ret;                                                        \
  49         unsigned long flags;                                            \
  50         spin_lock_irqsave(ATOMIC_HASH(v), flags);                       \
  51                                                                         \
  52         ret = (v->counter c_op i);                                      \
  53                                                                         \
  54         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);                  \
  55         return ret;                                                     \
  56 }                                                                       \
  57 EXPORT_SYMBOL(atomic_##op##_return);
  58
  59 ATOMIC_OP_RETURN(add, +=)
  60
  61 ATOMIC_FETCH_OP(add, +=)
  62 ATOMIC_FETCH_OP(and, &=)
  63 ATOMIC_FETCH_OP(or, |=)
  64 ATOMIC_FETCH_OP(xor, ^=)
  65
  66 #undef ATOMIC_FETCH_OP
  67 #undef ATOMIC_OP_RETURN
  68
  69 int atomic_xchg(atomic_t *v, int new)
  70 {
  71         int ret;
  72         unsigned long flags;
  73
  74         spin_lock_irqsave(ATOMIC_HASH(v), flags);
  75         ret = v->counter;
  76         v->counter = new;
  77         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
  78         return ret;
  79 }
  80 EXPORT_SYMBOL(atomic_xchg);
  81
  82 int atomic_cmpxchg(atomic_t *v, int old, int new)
  83 {
  84         int ret;
  85         unsigned long flags;
  86
  87         spin_lock_irqsave(ATOMIC_HASH(v), flags);
  88         ret = v->counter;
  89         if (likely(ret == old))
  90                 v->counter = new;
  91
  92         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
  93         return ret;
  94 }
  95 EXPORT_SYMBOL(atomic_cmpxchg);
  96
  97 int __atomic_add_unless(atomic_t *v, int a, int u)
  98 {
  99         int ret;
 100         unsigned long flags;
 101
 102         spin_lock_irqsave(ATOMIC_HASH(v), flags);
 103         ret = v->counter;
 104         if (ret != u)
 105                 v->counter += a;
 106         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
 107         return ret;
 108 }
 109 EXPORT_SYMBOL(__atomic_add_unless);
 110
 111 /* Atomic operations are already serializing */
 112 void atomic_set(atomic_t *v, int i)
 113 {
 114         unsigned long flags;
 115
 116         spin_lock_irqsave(ATOMIC_HASH(v), flags);
 117         v->counter = i;
 118         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
 119 }
 120 EXPORT_SYMBOL(atomic_set);
 121
 122 unsigned long ___set_bit(unsigned long *addr, unsigned long mask)
 123 {
 124         unsigned long old, flags;
 125
 126         spin_lock_irqsave(ATOMIC_HASH(addr), flags);
 127         old = *addr;
 128         *addr = old | mask;
 129         spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
 130
 131         return old & mask;
 132 }
 133 EXPORT_SYMBOL(___set_bit);
 134
 135 unsigned long ___clear_bit(unsigned long *addr, unsigned long mask)
 136 {
 137         unsigned long old, flags;
 138
 139         spin_lock_irqsave(ATOMIC_HASH(addr), flags);
 140         old = *addr;
 141         *addr = old & ~mask;
 142         spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
 143
 144         return old & mask;
 145 }
 146 EXPORT_SYMBOL(___clear_bit);
 147
 148 unsigned long ___change_bit(unsigned long *addr, unsigned long mask)
 149 {
 150         unsigned long old, flags;
 151
 152         spin_lock_irqsave(ATOMIC_HASH(addr), flags);
 153         old = *addr;
 154         *addr = old ^ mask;
 155         spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
 156
 157         return old & mask;
 158 }
 159 EXPORT_SYMBOL(___change_bit);
 160
 161 unsigned long __cmpxchg_u32(volatile u32 *ptr, u32 old, u32 new)
 162 {
 163         unsigned long flags;
 164         u32 prev;
 165
 166         spin_lock_irqsave(ATOMIC_HASH(ptr), flags);
 167         if ((prev = *ptr) == old)
 168                 *ptr = new;
 169         spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);
 170
 171         return (unsigned long)prev;
 172 }
 173 EXPORT_SYMBOL(__cmpxchg_u32);
 174
 175 unsigned long __xchg_u32(volatile u32 *ptr, u32 new)
 176 {
 177         unsigned long flags;
 178         u32 prev;
 179
 180         spin_lock_irqsave(ATOMIC_HASH(ptr), flags);
 181         prev = *ptr;
 182         *ptr = new;
 183         spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);
 184
 185         return (unsigned long)prev;
 186 }
 187 EXPORT_SYMBOL(__xchg_u32);