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_ */ 280