1/* atomic.h: atomic operation emulation for FR-V
  2 *
  3 * For an explanation of how atomic ops work in this arch, see:
  4 *   Documentation/frv/atomic-ops.txt
  5 *
  6 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
  7 * Written by David Howells (dhowells@redhat.com)
  8 *
  9 * This program is free software; you can redistribute it and/or
 10 * modify it under the terms of the GNU General Public License
 11 * as published by the Free Software Foundation; either version
 12 * 2 of the License, or (at your option) any later version.
 13 */
 14#ifndef _ASM_ATOMIC_H
 15#define _ASM_ATOMIC_H
 16
 17#include <linux/types.h>
 18#include <asm/cmpxchg.h>
 19#include <asm/barrier.h>
 20
 21#ifdef CONFIG_SMP
 22#error not SMP safe
 23#endif
 24
 25#include <asm/atomic_defs.h>
 26
 27/*
 28 * Atomic operations that C can't guarantee us.  Useful for
 29 * resource counting etc..
 30 *
 31 * We do not have SMP systems, so we don't have to deal with that.
 32 */
 33
 34#define ATOMIC_INIT(i)		{ (i) }
 35#define atomic_read(v)		READ_ONCE((v)->counter)
 36#define atomic_set(v, i)	WRITE_ONCE(((v)->counter), (i))
 37
 38static inline int atomic_inc_return(atomic_t *v)
 39{
 40	return __atomic_add_return(1, &v->counter);
 41}
 42
 43static inline int atomic_dec_return(atomic_t *v)
 44{
 45	return __atomic_sub_return(1, &v->counter);
 46}
 47
 48static inline int atomic_add_return(int i, atomic_t *v)
 49{
 50	return __atomic_add_return(i, &v->counter);
 51}
 52
 53static inline int atomic_sub_return(int i, atomic_t *v)
 54{
 55	return __atomic_sub_return(i, &v->counter);
 56}
 57
 58static inline int atomic_add_negative(int i, atomic_t *v)
 59{
 60	return atomic_add_return(i, v) < 0;
 61}
 62
 63static inline void atomic_add(int i, atomic_t *v)
 64{
 65	atomic_add_return(i, v);
 66}
 67
 68static inline void atomic_sub(int i, atomic_t *v)
 69{
 70	atomic_sub_return(i, v);
 71}
 72
 73static inline void atomic_inc(atomic_t *v)
 74{
 75	atomic_inc_return(v);
 76}
 77
 78static inline void atomic_dec(atomic_t *v)
 79{
 80	atomic_dec_return(v);
 81}
 82
 83#define atomic_sub_and_test(i,v)	(atomic_sub_return((i), (v)) == 0)
 84#define atomic_dec_and_test(v)		(atomic_sub_return(1, (v)) == 0)
 85#define atomic_inc_and_test(v)		(atomic_add_return(1, (v)) == 0)
 86
 87/*
 88 * 64-bit atomic ops
 89 */
 90typedef struct {
 91	long long counter;
 92} atomic64_t;
 93
 94#define ATOMIC64_INIT(i)	{ (i) }
 95
 96static inline long long atomic64_read(const atomic64_t *v)
 97{
 98	long long counter;
 99
100	asm("ldd%I1 %M1,%0"
101	    : "=e"(counter)
102	    : "m"(v->counter));
103
104	return counter;
105}
106
107static inline void atomic64_set(atomic64_t *v, long long i)
108{
109	asm volatile("std%I0 %1,%M0"
110		     : "=m"(v->counter)
111		     : "e"(i));
112}
113
114static inline long long atomic64_inc_return(atomic64_t *v)
115{
116	return __atomic64_add_return(1, &v->counter);
117}
118
119static inline long long atomic64_dec_return(atomic64_t *v)
120{
121	return __atomic64_sub_return(1, &v->counter);
122}
123
124static inline long long atomic64_add_return(long long i, atomic64_t *v)
125{
126	return __atomic64_add_return(i, &v->counter);
127}
128
129static inline long long atomic64_sub_return(long long i, atomic64_t *v)
130{
131	return __atomic64_sub_return(i, &v->counter);
132}
133
134static inline long long atomic64_add_negative(long long i, atomic64_t *v)
135{
136	return atomic64_add_return(i, v) < 0;
137}
138
139static inline void atomic64_add(long long i, atomic64_t *v)
140{
141	atomic64_add_return(i, v);
142}
143
144static inline void atomic64_sub(long long i, atomic64_t *v)
145{
146	atomic64_sub_return(i, v);
147}
148
149static inline void atomic64_inc(atomic64_t *v)
150{
151	atomic64_inc_return(v);
152}
153
154static inline void atomic64_dec(atomic64_t *v)
155{
156	atomic64_dec_return(v);
157}
158
159#define atomic64_sub_and_test(i,v)	(atomic64_sub_return((i), (v)) == 0)
160#define atomic64_dec_and_test(v)	(atomic64_dec_return((v)) == 0)
161#define atomic64_inc_and_test(v)	(atomic64_inc_return((v)) == 0)
162
163
164#define atomic_cmpxchg(v, old, new)	(cmpxchg(&(v)->counter, old, new))
165#define atomic_xchg(v, new)		(xchg(&(v)->counter, new))
166#define atomic64_cmpxchg(v, old, new)	(__cmpxchg_64(old, new, &(v)->counter))
167#define atomic64_xchg(v, new)		(__xchg_64(new, &(v)->counter))
168
169static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
170{
171	int c, old;
172	c = atomic_read(v);
173	for (;;) {
174		if (unlikely(c == (u)))
175			break;
176		old = atomic_cmpxchg((v), c, c + (a));
177		if (likely(old == c))
178			break;
179		c = old;
180	}
181	return c;
182}
183
184#define ATOMIC_OP(op)							\
185static inline void atomic_##op(int i, atomic_t *v)			\
186{									\
187	(void)__atomic32_fetch_##op(i, &v->counter);			\
188}									\
189									\
190static inline void atomic64_##op(long long i, atomic64_t *v)		\
191{									\
192	(void)__atomic64_fetch_##op(i, &v->counter);			\
193}
194
195ATOMIC_OP(or)
196ATOMIC_OP(and)
197ATOMIC_OP(xor)
198
199#undef ATOMIC_OP
200
201#endif /* _ASM_ATOMIC_H */