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 READ_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_FETCH_OP(op, c_op)                                       \
 125 static __inline__ int atomic_fetch_##op(int i, atomic_t *v)             \
 126 {                                                                       \
 127         unsigned long flags;                                            \
 128         int ret;                                                        \
 129                                                                         \
 130         _atomic_spin_lock_irqsave(v, flags);                            \
 131         ret = v->counter;                                               \
 132         v->counter c_op i;                                              \
 133         _atomic_spin_unlock_irqrestore(v, flags);                       \
 134                                                                         \
 135         return ret;                                                     \
 136 }
 137
 138 #define ATOMIC_OPS(op, c_op)                                            \
 139         ATOMIC_OP(op, c_op)                                             \
 140         ATOMIC_OP_RETURN(op, c_op)                                      \
 141         ATOMIC_FETCH_OP(op, c_op)
 142
 143 ATOMIC_OPS(add, +=)
 144 ATOMIC_OPS(sub, -=)
 145
 146 #undef ATOMIC_OPS
 147 #define ATOMIC_OPS(op, c_op)                                            \
 148         ATOMIC_OP(op, c_op)                                             \
 149         ATOMIC_FETCH_OP(op, c_op)
 150
 151 ATOMIC_OPS(and, &=)
 152 ATOMIC_OPS(or, |=)
 153 ATOMIC_OPS(xor, ^=)
 154
 155 #undef ATOMIC_OPS
 156 #undef ATOMIC_FETCH_OP
 157 #undef ATOMIC_OP_RETURN
 158 #undef ATOMIC_OP
 159
 160 #define atomic_inc(v)   (atomic_add(   1,(v)))
 161 #define atomic_dec(v)   (atomic_add(  -1,(v)))
 162
 163 #define atomic_inc_return(v)    (atomic_add_return(   1,(v)))
 164 #define atomic_dec_return(v)    (atomic_add_return(  -1,(v)))
 165
 166 #define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
 167
 168 /*
 169  * atomic_inc_and_test - increment and test
 170  * @v: pointer of type atomic_t
 171  *
 172  * Atomically increments @v by 1
 173  * and returns true if the result is zero, or false for all
 174  * other cases.
 175  */
 176 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
 177
 178 #define atomic_dec_and_test(v)  (atomic_dec_return(v) == 0)
 179
 180 #define atomic_sub_and_test(i,v)        (atomic_sub_return((i),(v)) == 0)
 181
 182 #define ATOMIC_INIT(i)  { (i) }
 183
 184 #ifdef CONFIG_64BIT
 185
 186 #define ATOMIC64_INIT(i) { (i) }
 187
 188 #define ATOMIC64_OP(op, c_op)                                           \
 189 static __inline__ void atomic64_##op(s64 i, atomic64_t *v)              \
 190 {                                                                       \
 191         unsigned long flags;                                            \
 192                                                                         \
 193         _atomic_spin_lock_irqsave(v, flags);                            \
 194         v->counter c_op i;                                              \
 195         _atomic_spin_unlock_irqrestore(v, flags);                       \
 196 }                                                                       \
 197
 198 #define ATOMIC64_OP_RETURN(op, c_op)                                    \
 199 static __inline__ s64 atomic64_##op##_return(s64 i, atomic64_t *v)      \
 200 {                                                                       \
 201         unsigned long flags;                                            \
 202         s64 ret;                                                        \
 203                                                                         \
 204         _atomic_spin_lock_irqsave(v, flags);                            \
 205         ret = (v->counter c_op i);                                      \
 206         _atomic_spin_unlock_irqrestore(v, flags);                       \
 207                                                                         \
 208         return ret;                                                     \
 209 }
 210
 211 #define ATOMIC64_FETCH_OP(op, c_op)                                     \
 212 static __inline__ s64 atomic64_fetch_##op(s64 i, atomic64_t *v)         \
 213 {                                                                       \
 214         unsigned long flags;                                            \
 215         s64 ret;                                                        \
 216                                                                         \
 217         _atomic_spin_lock_irqsave(v, flags);                            \
 218         ret = v->counter;                                               \
 219         v->counter c_op i;                                              \
 220         _atomic_spin_unlock_irqrestore(v, flags);                       \
 221                                                                         \
 222         return ret;                                                     \
 223 }
 224
 225 #define ATOMIC64_OPS(op, c_op)                                          \
 226         ATOMIC64_OP(op, c_op)                                           \
 227         ATOMIC64_OP_RETURN(op, c_op)                                    \
 228         ATOMIC64_FETCH_OP(op, c_op)
 229
 230 ATOMIC64_OPS(add, +=)
 231 ATOMIC64_OPS(sub, -=)
 232
 233 #undef ATOMIC64_OPS
 234 #define ATOMIC64_OPS(op, c_op)                                          \
 235         ATOMIC64_OP(op, c_op)                                           \
 236         ATOMIC64_FETCH_OP(op, c_op)
 237
 238 ATOMIC64_OPS(and, &=)
 239 ATOMIC64_OPS(or, |=)
 240 ATOMIC64_OPS(xor, ^=)
 241
 242 #undef ATOMIC64_OPS
 243 #undef ATOMIC64_FETCH_OP
 244 #undef ATOMIC64_OP_RETURN
 245 #undef ATOMIC64_OP
 246
 247 static __inline__ void
 248 atomic64_set(atomic64_t *v, s64 i)
 249 {
 250         unsigned long flags;
 251         _atomic_spin_lock_irqsave(v, flags);
 252
 253         v->counter = i;
 254
 255         _atomic_spin_unlock_irqrestore(v, flags);
 256 }
 257
 258 static __inline__ s64
 259 atomic64_read(const atomic64_t *v)
 260 {
 261         return ACCESS_ONCE((v)->counter);
 262 }
 263
 264 #define atomic64_inc(v)         (atomic64_add(   1,(v)))
 265 #define atomic64_dec(v)         (atomic64_add(  -1,(v)))
 266
 267 #define atomic64_inc_return(v)          (atomic64_add_return(   1,(v)))
 268 #define atomic64_dec_return(v)          (atomic64_add_return(  -1,(v)))
 269
 270 #define atomic64_add_negative(a, v)     (atomic64_add_return((a), (v)) < 0)
 271
 272 #define atomic64_inc_and_test(v)        (atomic64_inc_return(v) == 0)
 273 #define atomic64_dec_and_test(v)        (atomic64_dec_return(v) == 0)
 274 #define atomic64_sub_and_test(i,v)      (atomic64_sub_return((i),(v)) == 0)
 275
 276 /* exported interface */
 277 #define atomic64_cmpxchg(v, o, n) \
 278         ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
 279 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
 280
 281 /**
 282  * atomic64_add_unless - add unless the number is a given value
 283  * @v: pointer of type atomic64_t
 284  * @a: the amount to add to v...
 285  * @u: ...unless v is equal to u.
 286  *
 287  * Atomically adds @a to @v, so long as it was not @u.
 288  * Returns the old value of @v.
 289  */
 290 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
 291 {
 292         long c, old;
 293         c = atomic64_read(v);
 294         for (;;) {
 295                 if (unlikely(c == (u)))
 296                         break;
 297                 old = atomic64_cmpxchg((v), c, c + (a));
 298                 if (likely(old == c))
 299                         break;
 300                 c = old;
 301         }
 302         return c != (u);
 303 }
 304
 305 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 306
 307 /*
 308  * atomic64_dec_if_positive - decrement by 1 if old value positive
 309  * @v: pointer of type atomic_t
 310  *
 311  * The function returns the old value of *v minus 1, even if
 312  * the atomic variable, v, was not decremented.
 313  */
 314 static inline long atomic64_dec_if_positive(atomic64_t *v)
 315 {
 316         long c, old, dec;
 317         c = atomic64_read(v);
 318         for (;;) {
 319                 dec = c - 1;
 320                 if (unlikely(dec < 0))
 321                         break;
 322                 old = atomic64_cmpxchg((v), c, dec);
 323                 if (likely(old == c))
 324                         break;
 325                 c = old;
 326         }
 327         return dec;
 328 }
 329
 330 #endif /* !CONFIG_64BIT */
 331
 332
 333 #endif /* _ASM_PARISC_ATOMIC_H_ */