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