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/**
 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 */