1 /* MN10300 Atomic counter operations
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
14 #include <asm/irqflags.h>
15 #include <asm/cmpxchg.h>
16 #include <asm/barrier.h>
19 #include <asm-generic/atomic.h>
23 * Atomic operations that C can't guarantee us. Useful for
24 * resource counting etc..
27 #define ATOMIC_INIT(i) { (i) }
32 * atomic_read - read atomic variable
33 * @v: pointer of type atomic_t
35 * Atomically reads the value of @v. Note that the guaranteed
37 #define atomic_read(v) READ_ONCE((v)->counter)
40 * atomic_set - set atomic variable
41 * @v: pointer of type atomic_t
44 * Atomically sets the value of @v to @i. Note that the guaranteed
46 #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
48 #define ATOMIC_OP(op) \
49 static inline void atomic_##op(int i, atomic_t *v) \
54 "1: mov %4,(_AAR,%3) \n" \
55 " mov (_ADR,%3),%1 \n" \
57 " mov %1,(_ADR,%3) \n" \
58 " mov (_ADR,%3),%0 \n" /* flush */ \
59 " mov (_ASR,%3),%0 \n" \
62 : "=&r"(status), "=&r"(retval), "=m"(v->counter) \
63 : "a"(ATOMIC_OPS_BASE_ADDR), "r"(&v->counter), "r"(i) \
67 #define ATOMIC_OP_RETURN(op) \
68 static inline int atomic_##op##_return(int i, atomic_t *v) \
73 "1: mov %4,(_AAR,%3) \n" \
74 " mov (_ADR,%3),%1 \n" \
76 " mov %1,(_ADR,%3) \n" \
77 " mov (_ADR,%3),%0 \n" /* flush */ \
78 " mov (_ASR,%3),%0 \n" \
81 : "=&r"(status), "=&r"(retval), "=m"(v->counter) \
82 : "a"(ATOMIC_OPS_BASE_ADDR), "r"(&v->counter), "r"(i) \
87 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op)
97 #undef ATOMIC_OP_RETURN
100 static inline int atomic_add_negative(int i, atomic_t *v)
102 return atomic_add_return(i, v) < 0;
105 static inline void atomic_inc(atomic_t *v)
107 atomic_add_return(1, v);
110 static inline void atomic_dec(atomic_t *v)
112 atomic_sub_return(1, v);
115 #define atomic_dec_return(v) atomic_sub_return(1, (v))
116 #define atomic_inc_return(v) atomic_add_return(1, (v))
118 #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
119 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
120 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
122 #define __atomic_add_unless(v, a, u) \
125 c = atomic_read(v); \
126 while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
131 #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
132 #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
134 #endif /* __KERNEL__ */
135 #endif /* CONFIG_SMP */
136 #endif /* _ASM_ATOMIC_H */