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 */