1/* 2 * Copyright 2010 Tilera Corporation. All Rights Reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation, version 2. 7 * 8 * This program is distributed in the hope that it will be useful, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 11 * NON INFRINGEMENT. See the GNU General Public License for 12 * more details. 13 * 14 * Atomic primitives. 15 */ 16 17#ifndef _ASM_TILE_ATOMIC_H 18#define _ASM_TILE_ATOMIC_H 19 20#include <asm/cmpxchg.h> 21 22#ifndef __ASSEMBLY__ 23 24#include <linux/compiler.h> 25#include <linux/types.h> 26 27#define ATOMIC_INIT(i) { (i) } 28 29/** 30 * atomic_read - read atomic variable 31 * @v: pointer of type atomic_t 32 * 33 * Atomically reads the value of @v. 34 */ 35static inline int atomic_read(const atomic_t *v) 36{ 37 return ACCESS_ONCE(v->counter); 38} 39 40/** 41 * atomic_sub_return - subtract integer and return 42 * @v: pointer of type atomic_t 43 * @i: integer value to subtract 44 * 45 * Atomically subtracts @i from @v and returns @v - @i 46 */ 47#define atomic_sub_return(i, v) atomic_add_return((int)(-(i)), (v)) 48 49/** 50 * atomic_sub - subtract integer from atomic variable 51 * @i: integer value to subtract 52 * @v: pointer of type atomic_t 53 * 54 * Atomically subtracts @i from @v. 55 */ 56#define atomic_sub(i, v) atomic_add((int)(-(i)), (v)) 57 58/** 59 * atomic_sub_and_test - subtract value from variable and test result 60 * @i: integer value to subtract 61 * @v: pointer of type atomic_t 62 * 63 * Atomically subtracts @i from @v and returns true if the result is 64 * zero, or false for all other cases. 65 */ 66#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0) 67 68/** 69 * atomic_inc_return - increment memory and return 70 * @v: pointer of type atomic_t 71 * 72 * Atomically increments @v by 1 and returns the new value. 73 */ 74#define atomic_inc_return(v) atomic_add_return(1, (v)) 75 76/** 77 * atomic_dec_return - decrement memory and return 78 * @v: pointer of type atomic_t 79 * 80 * Atomically decrements @v by 1 and returns the new value. 81 */ 82#define atomic_dec_return(v) atomic_sub_return(1, (v)) 83 84/** 85 * atomic_inc - increment atomic variable 86 * @v: pointer of type atomic_t 87 * 88 * Atomically increments @v by 1. 89 */ 90#define atomic_inc(v) atomic_add(1, (v)) 91 92/** 93 * atomic_dec - decrement atomic variable 94 * @v: pointer of type atomic_t 95 * 96 * Atomically decrements @v by 1. 97 */ 98#define atomic_dec(v) atomic_sub(1, (v)) 99 100/** 101 * atomic_dec_and_test - decrement and test 102 * @v: pointer of type atomic_t 103 * 104 * Atomically decrements @v by 1 and returns true if the result is 0. 105 */ 106#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0) 107 108/** 109 * atomic_inc_and_test - increment and test 110 * @v: pointer of type atomic_t 111 * 112 * Atomically increments @v by 1 and returns true if the result is 0. 113 */ 114#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0) 115 116/** 117 * atomic_xchg - atomically exchange contents of memory with a new value 118 * @v: pointer of type atomic_t 119 * @i: integer value to store in memory 120 * 121 * Atomically sets @v to @i and returns old @v 122 */ 123static inline int atomic_xchg(atomic_t *v, int n) 124{ 125 return xchg(&v->counter, n); 126} 127 128/** 129 * atomic_cmpxchg - atomically exchange contents of memory if it matches 130 * @v: pointer of type atomic_t 131 * @o: old value that memory should have 132 * @n: new value to write to memory if it matches 133 * 134 * Atomically checks if @v holds @o and replaces it with @n if so. 135 * Returns the old value at @v. 136 */ 137static inline int atomic_cmpxchg(atomic_t *v, int o, int n) 138{ 139 return cmpxchg(&v->counter, o, n); 140} 141 142/** 143 * atomic_add_negative - add and test if negative 144 * @v: pointer of type atomic_t 145 * @i: integer value to add 146 * 147 * Atomically adds @i to @v and returns true if the result is 148 * negative, or false when result is greater than or equal to zero. 149 */ 150#define atomic_add_negative(i, v) (atomic_add_return((i), (v)) < 0) 151 152#endif /* __ASSEMBLY__ */ 153 154#ifndef __tilegx__ 155#include <asm/atomic_32.h> 156#else 157#include <asm/atomic_64.h> 158#endif 159 160#ifndef __ASSEMBLY__ 161 162/** 163 * atomic64_xchg - atomically exchange contents of memory with a new value 164 * @v: pointer of type atomic64_t 165 * @i: integer value to store in memory 166 * 167 * Atomically sets @v to @i and returns old @v 168 */ 169static inline long long atomic64_xchg(atomic64_t *v, long long n) 170{ 171 return xchg64(&v->counter, n); 172} 173 174/** 175 * atomic64_cmpxchg - atomically exchange contents of memory if it matches 176 * @v: pointer of type atomic64_t 177 * @o: old value that memory should have 178 * @n: new value to write to memory if it matches 179 * 180 * Atomically checks if @v holds @o and replaces it with @n if so. 181 * Returns the old value at @v. 182 */ 183static inline long long atomic64_cmpxchg(atomic64_t *v, long long o, 184 long long n) 185{ 186 return cmpxchg64(&v->counter, o, n); 187} 188 189static inline long long atomic64_dec_if_positive(atomic64_t *v) 190{ 191 long long c, old, dec; 192 193 c = atomic64_read(v); 194 for (;;) { 195 dec = c - 1; 196 if (unlikely(dec < 0)) 197 break; 198 old = atomic64_cmpxchg((v), c, dec); 199 if (likely(old == c)) 200 break; 201 c = old; 202 } 203 return dec; 204} 205 206#endif /* __ASSEMBLY__ */ 207 208#endif /* _ASM_TILE_ATOMIC_H */ 209