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 /* It's possible to reduce all atomic operations to either 59 * __atomic_add_return, atomic_set and atomic_read (the latter 60 * is there only for consistency). 61 */ 62 63 static __inline__ int __atomic_add_return(int i, atomic_t *v) 64 { 65 int ret; 66 unsigned long flags; 67 _atomic_spin_lock_irqsave(v, flags); 68 69 ret = (v->counter += i); 70 71 _atomic_spin_unlock_irqrestore(v, flags); 72 return ret; 73 } 74 75 static __inline__ void atomic_set(atomic_t *v, int i) 76 { 77 unsigned long flags; 78 _atomic_spin_lock_irqsave(v, flags); 79 80 v->counter = i; 81 82 _atomic_spin_unlock_irqrestore(v, flags); 83 } 84 85 static __inline__ int atomic_read(const atomic_t *v) 86 { 87 return (*(volatile int *)&(v)->counter); 88 } 89 90 /* exported interface */ 91 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n))) 92 #define atomic_xchg(v, new) (xchg(&((v)->counter), new)) 93 94 /** 95 * __atomic_add_unless - add unless the number is a given value 96 * @v: pointer of type atomic_t 97 * @a: the amount to add to v... 98 * @u: ...unless v is equal to u. 99 * 100 * Atomically adds @a to @v, so long as it was not @u. 101 * Returns the old value of @v. 102 */ 103 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u) 104 { 105 int c, old; 106 c = atomic_read(v); 107 for (;;) { 108 if (unlikely(c == (u))) 109 break; 110 old = atomic_cmpxchg((v), c, c + (a)); 111 if (likely(old == c)) 112 break; 113 c = old; 114 } 115 return c; 116 } 117 118 119 #define atomic_add(i,v) ((void)(__atomic_add_return( (i),(v)))) 120 #define atomic_sub(i,v) ((void)(__atomic_add_return(-((int) (i)),(v)))) 121 #define atomic_inc(v) ((void)(__atomic_add_return( 1,(v)))) 122 #define atomic_dec(v) ((void)(__atomic_add_return( -1,(v)))) 123 124 #define atomic_add_return(i,v) (__atomic_add_return( (i),(v))) 125 #define atomic_sub_return(i,v) (__atomic_add_return(-(i),(v))) 126 #define atomic_inc_return(v) (__atomic_add_return( 1,(v))) 127 #define atomic_dec_return(v) (__atomic_add_return( -1,(v))) 128 129 #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0) 130 131 /* 132 * atomic_inc_and_test - increment and test 133 * @v: pointer of type atomic_t 134 * 135 * Atomically increments @v by 1 136 * and returns true if the result is zero, or false for all 137 * other cases. 138 */ 139 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0) 140 141 #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0) 142 143 #define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0) 144 145 #define ATOMIC_INIT(i) { (i) } 146 147 #ifdef CONFIG_64BIT 148 149 #define ATOMIC64_INIT(i) { (i) } 150 151 static __inline__ s64 152 __atomic64_add_return(s64 i, atomic64_t *v) 153 { 154 s64 ret; 155 unsigned long flags; 156 _atomic_spin_lock_irqsave(v, flags); 157 158 ret = (v->counter += i); 159 160 _atomic_spin_unlock_irqrestore(v, flags); 161 return ret; 162 } 163 164 static __inline__ void 165 atomic64_set(atomic64_t *v, s64 i) 166 { 167 unsigned long flags; 168 _atomic_spin_lock_irqsave(v, flags); 169 170 v->counter = i; 171 172 _atomic_spin_unlock_irqrestore(v, flags); 173 } 174 175 static __inline__ s64 176 atomic64_read(const atomic64_t *v) 177 { 178 return (*(volatile long *)&(v)->counter); 179 } 180 181 #define atomic64_add(i,v) ((void)(__atomic64_add_return( ((s64)(i)),(v)))) 182 #define atomic64_sub(i,v) ((void)(__atomic64_add_return(-((s64)(i)),(v)))) 183 #define atomic64_inc(v) ((void)(__atomic64_add_return( 1,(v)))) 184 #define atomic64_dec(v) ((void)(__atomic64_add_return( -1,(v)))) 185 186 #define atomic64_add_return(i,v) (__atomic64_add_return( ((s64)(i)),(v))) 187 #define atomic64_sub_return(i,v) (__atomic64_add_return(-((s64)(i)),(v))) 188 #define atomic64_inc_return(v) (__atomic64_add_return( 1,(v))) 189 #define atomic64_dec_return(v) (__atomic64_add_return( -1,(v))) 190 191 #define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0) 192 193 #define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0) 194 #define atomic64_dec_and_test(v) (atomic64_dec_return(v) == 0) 195 #define atomic64_sub_and_test(i,v) (atomic64_sub_return((i),(v)) == 0) 196 197 /* exported interface */ 198 #define atomic64_cmpxchg(v, o, n) \ 199 ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n))) 200 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new)) 201 202 /** 203 * atomic64_add_unless - add unless the number is a given value 204 * @v: pointer of type atomic64_t 205 * @a: the amount to add to v... 206 * @u: ...unless v is equal to u. 207 * 208 * Atomically adds @a to @v, so long as it was not @u. 209 * Returns the old value of @v. 210 */ 211 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u) 212 { 213 long c, old; 214 c = atomic64_read(v); 215 for (;;) { 216 if (unlikely(c == (u))) 217 break; 218 old = atomic64_cmpxchg((v), c, c + (a)); 219 if (likely(old == c)) 220 break; 221 c = old; 222 } 223 return c != (u); 224 } 225 226 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0) 227 228 /* 229 * atomic64_dec_if_positive - decrement by 1 if old value positive 230 * @v: pointer of type atomic_t 231 * 232 * The function returns the old value of *v minus 1, even if 233 * the atomic variable, v, was not decremented. 234 */ 235 static inline long atomic64_dec_if_positive(atomic64_t *v) 236 { 237 long c, old, dec; 238 c = atomic64_read(v); 239 for (;;) { 240 dec = c - 1; 241 if (unlikely(dec < 0)) 242 break; 243 old = atomic64_cmpxchg((v), c, dec); 244 if (likely(old == c)) 245 break; 246 c = old; 247 } 248 return dec; 249 } 250 251 #endif /* !CONFIG_64BIT */ 252 253 254 #endif /* _ASM_PARISC_ATOMIC_H_ */ 255