1/*
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#ifndef _ASM_ARC_ATOMIC_H
10#define _ASM_ARC_ATOMIC_H
11
12#ifndef __ASSEMBLY__
13
14#include <linux/types.h>
15#include <linux/compiler.h>
16#include <asm/cmpxchg.h>
17#include <asm/barrier.h>
18#include <asm/smp.h>
19
20#define atomic_read(v)  ((v)->counter)
21
22#ifdef CONFIG_ARC_HAS_LLSC
23
24#define atomic_set(v, i) (((v)->counter) = (i))
25
26#define ATOMIC_OP(op, c_op, asm_op)					\
27static inline void atomic_##op(int i, atomic_t *v)			\
28{									\
29	unsigned int temp;						\
30									\
31	__asm__ __volatile__(						\
32	"1:	llock   %0, [%1]	\n"				\
33	"	" #asm_op " %0, %0, %2	\n"				\
34	"	scond   %0, [%1]	\n"				\
35	"	bnz     1b		\n"				\
36	: "=&r"(temp)	/* Early clobber, to prevent reg reuse */	\
37	: "r"(&v->counter), "ir"(i)					\
38	: "cc");							\
39}									\
40
41#define ATOMIC_OP_RETURN(op, c_op, asm_op)				\
42static inline int atomic_##op##_return(int i, atomic_t *v)		\
43{									\
44	unsigned int temp;						\
45									\
46	__asm__ __volatile__(						\
47	"1:	llock   %0, [%1]	\n"				\
48	"	" #asm_op " %0, %0, %2	\n"				\
49	"	scond   %0, [%1]	\n"				\
50	"	bnz     1b		\n"				\
51	: "=&r"(temp)							\
52	: "r"(&v->counter), "ir"(i)					\
53	: "cc");							\
54									\
55	return temp;							\
56}
57
58#else	/* !CONFIG_ARC_HAS_LLSC */
59
60#ifndef CONFIG_SMP
61
62 /* violating atomic_xxx API locking protocol in UP for optimization sake */
63#define atomic_set(v, i) (((v)->counter) = (i))
64
65#else
66
67static inline void atomic_set(atomic_t *v, int i)
68{
69	/*
70	 * Independent of hardware support, all of the atomic_xxx() APIs need
71	 * to follow the same locking rules to make sure that a "hardware"
72	 * atomic insn (e.g. LD) doesn't clobber an "emulated" atomic insn
73	 * sequence
74	 *
75	 * Thus atomic_set() despite being 1 insn (and seemingly atomic)
76	 * requires the locking.
77	 */
78	unsigned long flags;
79
80	atomic_ops_lock(flags);
81	v->counter = i;
82	atomic_ops_unlock(flags);
83}
84
85#endif
86
87/*
88 * Non hardware assisted Atomic-R-M-W
89 * Locking would change to irq-disabling only (UP) and spinlocks (SMP)
90 */
91
92#define ATOMIC_OP(op, c_op, asm_op)					\
93static inline void atomic_##op(int i, atomic_t *v)			\
94{									\
95	unsigned long flags;						\
96									\
97	atomic_ops_lock(flags);						\
98	v->counter c_op i;						\
99	atomic_ops_unlock(flags);					\
100}
101
102#define ATOMIC_OP_RETURN(op, c_op)					\
103static inline int atomic_##op##_return(int i, atomic_t *v)		\
104{									\
105	unsigned long flags;						\
106	unsigned long temp;						\
107									\
108	atomic_ops_lock(flags);						\
109	temp = v->counter;						\
110	temp c_op i;							\
111	v->counter = temp;						\
112	atomic_ops_unlock(flags);					\
113									\
114	return temp;							\
115}
116
117#endif /* !CONFIG_ARC_HAS_LLSC */
118
119#define ATOMIC_OPS(op, c_op, asm_op)					\
120	ATOMIC_OP(op, c_op, asm_op)					\
121	ATOMIC_OP_RETURN(op, c_op, asm_op)
122
123ATOMIC_OPS(add, +=, add)
124ATOMIC_OPS(sub, -=, sub)
125ATOMIC_OP(and, &=, and)
126
127#define atomic_clear_mask(mask, v) atomic_and(~(mask), (v))
128
129#undef ATOMIC_OPS
130#undef ATOMIC_OP_RETURN
131#undef ATOMIC_OP
132
133/**
134 * __atomic_add_unless - add unless the number is a given value
135 * @v: pointer of type atomic_t
136 * @a: the amount to add to v...
137 * @u: ...unless v is equal to u.
138 *
139 * Atomically adds @a to @v, so long as it was not @u.
140 * Returns the old value of @v
141 */
142#define __atomic_add_unless(v, a, u)					\
143({									\
144	int c, old;							\
145	c = atomic_read(v);						\
146	while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c)\
147		c = old;						\
148	c;								\
149})
150
151#define atomic_inc_not_zero(v)		atomic_add_unless((v), 1, 0)
152
153#define atomic_inc(v)			atomic_add(1, v)
154#define atomic_dec(v)			atomic_sub(1, v)
155
156#define atomic_inc_and_test(v)		(atomic_add_return(1, v) == 0)
157#define atomic_dec_and_test(v)		(atomic_sub_return(1, v) == 0)
158#define atomic_inc_return(v)		atomic_add_return(1, (v))
159#define atomic_dec_return(v)		atomic_sub_return(1, (v))
160#define atomic_sub_and_test(i, v)	(atomic_sub_return(i, v) == 0)
161
162#define atomic_add_negative(i, v)	(atomic_add_return(i, v) < 0)
163
164#define ATOMIC_INIT(i)			{ (i) }
165
166#include <asm-generic/atomic64.h>
167
168#endif
169
170#endif
171