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 READ_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#define atomic_fetch_sub(i, v) atomic_fetch_add(-(int)(i), (v)) 50 51/** 52 * atomic_sub - subtract integer from atomic variable 53 * @i: integer value to subtract 54 * @v: pointer of type atomic_t 55 * 56 * Atomically subtracts @i from @v. 57 */ 58#define atomic_sub(i, v) atomic_add((int)(-(i)), (v)) 59 60/** 61 * atomic_sub_and_test - subtract value from variable and test result 62 * @i: integer value to subtract 63 * @v: pointer of type atomic_t 64 * 65 * Atomically subtracts @i from @v and returns true if the result is 66 * zero, or false for all other cases. 67 */ 68#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0) 69 70/** 71 * atomic_inc_return - increment memory and return 72 * @v: pointer of type atomic_t 73 * 74 * Atomically increments @v by 1 and returns the new value. 75 */ 76#define atomic_inc_return(v) atomic_add_return(1, (v)) 77 78/** 79 * atomic_dec_return - decrement memory and return 80 * @v: pointer of type atomic_t 81 * 82 * Atomically decrements @v by 1 and returns the new value. 83 */ 84#define atomic_dec_return(v) atomic_sub_return(1, (v)) 85 86/** 87 * atomic_inc - increment atomic variable 88 * @v: pointer of type atomic_t 89 * 90 * Atomically increments @v by 1. 91 */ 92#define atomic_inc(v) atomic_add(1, (v)) 93 94/** 95 * atomic_dec - decrement atomic variable 96 * @v: pointer of type atomic_t 97 * 98 * Atomically decrements @v by 1. 99 */ 100#define atomic_dec(v) atomic_sub(1, (v)) 101 102/** 103 * atomic_dec_and_test - decrement and test 104 * @v: pointer of type atomic_t 105 * 106 * Atomically decrements @v by 1 and returns true if the result is 0. 107 */ 108#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0) 109 110/** 111 * atomic_inc_and_test - increment and test 112 * @v: pointer of type atomic_t 113 * 114 * Atomically increments @v by 1 and returns true if the result is 0. 115 */ 116#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0) 117 118/** 119 * atomic_xchg - atomically exchange contents of memory with a new value 120 * @v: pointer of type atomic_t 121 * @i: integer value to store in memory 122 * 123 * Atomically sets @v to @i and returns old @v 124 */ 125static inline int atomic_xchg(atomic_t *v, int n) 126{ 127 return xchg(&v->counter, n); 128} 129 130/** 131 * atomic_cmpxchg - atomically exchange contents of memory if it matches 132 * @v: pointer of type atomic_t 133 * @o: old value that memory should have 134 * @n: new value to write to memory if it matches 135 * 136 * Atomically checks if @v holds @o and replaces it with @n if so. 137 * Returns the old value at @v. 138 */ 139static inline int atomic_cmpxchg(atomic_t *v, int o, int n) 140{ 141 return cmpxchg(&v->counter, o, n); 142} 143 144/** 145 * atomic_add_negative - add and test if negative 146 * @v: pointer of type atomic_t 147 * @i: integer value to add 148 * 149 * Atomically adds @i to @v and returns true if the result is 150 * negative, or false when result is greater than or equal to zero. 151 */ 152#define atomic_add_negative(i, v) (atomic_add_return((i), (v)) < 0) 153 154#endif /* __ASSEMBLY__ */ 155 156#ifndef __tilegx__ 157#include <asm/atomic_32.h> 158#else 159#include <asm/atomic_64.h> 160#endif 161 162#ifndef __ASSEMBLY__ 163 164/** 165 * atomic64_xchg - atomically exchange contents of memory with a new value 166 * @v: pointer of type atomic64_t 167 * @i: integer value to store in memory 168 * 169 * Atomically sets @v to @i and returns old @v 170 */ 171static inline long long atomic64_xchg(atomic64_t *v, long long n) 172{ 173 return xchg64(&v->counter, n); 174} 175 176/** 177 * atomic64_cmpxchg - atomically exchange contents of memory if it matches 178 * @v: pointer of type atomic64_t 179 * @o: old value that memory should have 180 * @n: new value to write to memory if it matches 181 * 182 * Atomically checks if @v holds @o and replaces it with @n if so. 183 * Returns the old value at @v. 184 */ 185static inline long long atomic64_cmpxchg(atomic64_t *v, long long o, 186 long long n) 187{ 188 return cmpxchg64(&v->counter, o, n); 189} 190 191static inline long long atomic64_dec_if_positive(atomic64_t *v) 192{ 193 long long c, old, dec; 194 195 c = atomic64_read(v); 196 for (;;) { 197 dec = c - 1; 198 if (unlikely(dec < 0)) 199 break; 200 old = atomic64_cmpxchg((v), c, dec); 201 if (likely(old == c)) 202 break; 203 c = old; 204 } 205 return dec; 206} 207 208#endif /* __ASSEMBLY__ */ 209 210#endif /* _ASM_TILE_ATOMIC_H */ 211