kernel/arch/parisc/include/asm/atomic.h

   1 /* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
   2  * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
   3  */
   4
   5 #ifndef _ASM_PARISC_ATOMIC_H_
   6 #define _ASM_PARISC_ATOMIC_H_
   7
   8 #include <linux/types.h>
   9 #include <asm/cmpxchg.h>
  10 #include <asm/barrier.h>
  11
  12 /*
  13  * Atomic operations that C can't guarantee us.  Useful for
  14  * resource counting etc..
  15  *
  16  * And probably incredibly slow on parisc.  OTOH, we don't
  17  * have to write any serious assembly.   prumpf
  18  */
  19
  20 #ifdef CONFIG_SMP
  21 #include <asm/spinlock.h>
  22 #include <asm/cache.h>          /* we use L1_CACHE_BYTES */
  23
  24 /* Use an array of spinlocks for our atomic_ts.
  25  * Hash function to index into a different SPINLOCK.
  26  * Since "a" is usually an address, use one spinlock per cacheline.
  27  */
  28 #  define ATOMIC_HASH_SIZE 4
  29 #  define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) (a))/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ]))
  30
  31 extern arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
  32
  33 /* Can't use raw_spin_lock_irq because of #include problems, so
  34  * this is the substitute */
  35 #define _atomic_spin_lock_irqsave(l,f) do {     \
  36         arch_spinlock_t *s = ATOMIC_HASH(l);            \
  37         local_irq_save(f);                      \
  38         arch_spin_lock(s);                      \
  39 } while(0)
  40
  41 #define _atomic_spin_unlock_irqrestore(l,f) do {        \
  42         arch_spinlock_t *s = ATOMIC_HASH(l);                    \
  43         arch_spin_unlock(s);                            \
  44         local_irq_restore(f);                           \
  45 } while(0)
  46
  47
  48 #else
  49 #  define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0)
  50 #  define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0)
  51 #endif
  52
  53 /*
  54  * Note that we need not lock read accesses - aligned word writes/reads
  55  * are atomic, so a reader never sees inconsistent values.
  56  */
  57
  58 static __inline__ void atomic_set(atomic_t *v, int i)
  59 {
  60         unsigned long flags;
  61         _atomic_spin_lock_irqsave(v, flags);
  62
  63         v->counter = i;
  64
  65         _atomic_spin_unlock_irqrestore(v, flags);
  66 }
  67
  68 static __inline__ int atomic_read(const atomic_t *v)
  69 {
  70         return ACCESS_ONCE((v)->counter);
  71 }
  72
  73 /* exported interface */
  74 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
  75 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
  76
  77 /**
  78  * __atomic_add_unless - add unless the number is a given value
  79  * @v: pointer of type atomic_t
  80  * @a: the amount to add to v...
  81  * @u: ...unless v is equal to u.
  82  *
  83  * Atomically adds @a to @v, so long as it was not @u.
  84  * Returns the old value of @v.
  85  */
  86 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
  87 {
  88         int c, old;
  89         c = atomic_read(v);
  90         for (;;) {
  91                 if (unlikely(c == (u)))
  92                         break;
  93                 old = atomic_cmpxchg((v), c, c + (a));
  94                 if (likely(old == c))
  95                         break;
  96                 c = old;
  97         }
  98         return c;
  99 }
 100
 101 #define ATOMIC_OP(op, c_op)                                             \
 102 static __inline__ void atomic_##op(int i, atomic_t *v)                  \
 103 {                                                                       \
 104         unsigned long flags;                                            \
 105                                                                         \
 106         _atomic_spin_lock_irqsave(v, flags);                            \
 107         v->counter c_op i;                                              \
 108         _atomic_spin_unlock_irqrestore(v, flags);                       \
 109 }                                                                       \
 110
 111 #define ATOMIC_OP_RETURN(op, c_op)                                      \
 112 static __inline__ int atomic_##op##_return(int i, atomic_t *v)          \
 113 {                                                                       \
 114         unsigned long flags;                                            \
 115         int ret;                                                        \
 116                                                                         \
 117         _atomic_spin_lock_irqsave(v, flags);                            \
 118         ret = (v->counter c_op i);                                      \
 119         _atomic_spin_unlock_irqrestore(v, flags);                       \
 120                                                                         \
 121         return ret;                                                     \
 122 }
 123
 124 #define ATOMIC_OPS(op, c_op) ATOMIC_OP(op, c_op) ATOMIC_OP_RETURN(op, c_op)
 125
 126 ATOMIC_OPS(add, +=)
 127 ATOMIC_OPS(sub, -=)
 128
 129 #undef ATOMIC_OPS
 130 #undef ATOMIC_OP_RETURN
 131 #undef ATOMIC_OP
 132
 133 #define atomic_inc(v)   (atomic_add(   1,(v)))
 134 #define atomic_dec(v)   (atomic_add(  -1,(v)))
 135
 136 #define atomic_inc_return(v)    (atomic_add_return(   1,(v)))
 137 #define atomic_dec_return(v)    (atomic_add_return(  -1,(v)))
 138
 139 #define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
 140
 141 /*
 142  * atomic_inc_and_test - increment and test
 143  * @v: pointer of type atomic_t
 144  *
 145  * Atomically increments @v by 1
 146  * and returns true if the result is zero, or false for all
 147  * other cases.
 148  */
 149 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
 150
 151 #define atomic_dec_and_test(v)  (atomic_dec_return(v) == 0)
 152
 153 #define atomic_sub_and_test(i,v)        (atomic_sub_return((i),(v)) == 0)
 154
 155 #define ATOMIC_INIT(i)  { (i) }
 156
 157 #ifdef CONFIG_64BIT
 158
 159 #define ATOMIC64_INIT(i) { (i) }
 160
 161 #define ATOMIC64_OP(op, c_op)                                           \
 162 static __inline__ void atomic64_##op(s64 i, atomic64_t *v)              \
 163 {                                                                       \
 164         unsigned long flags;                                            \
 165                                                                         \
 166         _atomic_spin_lock_irqsave(v, flags);                            \
 167         v->counter c_op i;                                              \
 168         _atomic_spin_unlock_irqrestore(v, flags);                       \
 169 }                                                                       \
 170
 171 #define ATOMIC64_OP_RETURN(op, c_op)                                    \
 172 static __inline__ s64 atomic64_##op##_return(s64 i, atomic64_t *v)      \
 173 {                                                                       \
 174         unsigned long flags;                                            \
 175         s64 ret;                                                        \
 176                                                                         \
 177         _atomic_spin_lock_irqsave(v, flags);                            \
 178         ret = (v->counter c_op i);                                      \
 179         _atomic_spin_unlock_irqrestore(v, flags);                       \
 180                                                                         \
 181         return ret;                                                     \
 182 }
 183
 184 #define ATOMIC64_OPS(op, c_op) ATOMIC64_OP(op, c_op) ATOMIC64_OP_RETURN(op, c_op)
 185
 186 ATOMIC64_OPS(add, +=)
 187 ATOMIC64_OPS(sub, -=)
 188
 189 #undef ATOMIC64_OPS
 190 #undef ATOMIC64_OP_RETURN
 191 #undef ATOMIC64_OP
 192
 193 static __inline__ void
 194 atomic64_set(atomic64_t *v, s64 i)
 195 {
 196         unsigned long flags;
 197         _atomic_spin_lock_irqsave(v, flags);
 198
 199         v->counter = i;
 200
 201         _atomic_spin_unlock_irqrestore(v, flags);
 202 }
 203
 204 static __inline__ s64
 205 atomic64_read(const atomic64_t *v)
 206 {
 207         return ACCESS_ONCE((v)->counter);
 208 }
 209
 210 #define atomic64_inc(v)         (atomic64_add(   1,(v)))
 211 #define atomic64_dec(v)         (atomic64_add(  -1,(v)))
 212
 213 #define atomic64_inc_return(v)          (atomic64_add_return(   1,(v)))
 214 #define atomic64_dec_return(v)          (atomic64_add_return(  -1,(v)))
 215
 216 #define atomic64_add_negative(a, v)     (atomic64_add_return((a), (v)) < 0)
 217
 218 #define atomic64_inc_and_test(v)        (atomic64_inc_return(v) == 0)
 219 #define atomic64_dec_and_test(v)        (atomic64_dec_return(v) == 0)
 220 #define atomic64_sub_and_test(i,v)      (atomic64_sub_return((i),(v)) == 0)
 221
 222 /* exported interface */
 223 #define atomic64_cmpxchg(v, o, n) \
 224         ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
 225 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
 226
 227 /**
 228  * atomic64_add_unless - add unless the number is a given value
 229  * @v: pointer of type atomic64_t
 230  * @a: the amount to add to v...
 231  * @u: ...unless v is equal to u.
 232  *
 233  * Atomically adds @a to @v, so long as it was not @u.
 234  * Returns the old value of @v.
 235  */
 236 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
 237 {
 238         long c, old;
 239         c = atomic64_read(v);
 240         for (;;) {
 241                 if (unlikely(c == (u)))
 242                         break;
 243                 old = atomic64_cmpxchg((v), c, c + (a));
 244                 if (likely(old == c))
 245                         break;
 246                 c = old;
 247         }
 248         return c != (u);
 249 }
 250
 251 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 252
 253 /*
 254  * atomic64_dec_if_positive - decrement by 1 if old value positive
 255  * @v: pointer of type atomic_t
 256  *
 257  * The function returns the old value of *v minus 1, even if
 258  * the atomic variable, v, was not decremented.
 259  */
 260 static inline long atomic64_dec_if_positive(atomic64_t *v)
 261 {
 262         long c, old, dec;
 263         c = atomic64_read(v);
 264         for (;;) {
 265                 dec = c - 1;
 266                 if (unlikely(dec < 0))
 267                         break;
 268                 old = atomic64_cmpxchg((v), c, dec);
 269                 if (likely(old == c))
 270                         break;
 271                 c = old;
 272         }
 273         return dec;
 274 }
 275
 276 #endif /* !CONFIG_64BIT */
 277
 278
 279 #endif /* _ASM_PARISC_ATOMIC_H_ */