1#ifndef _ASM_IA64_ATOMIC_H
2#define _ASM_IA64_ATOMIC_H
3
4/*
5 * Atomic operations that C can't guarantee us.  Useful for
6 * resource counting etc..
7 *
8 * NOTE: don't mess with the types below!  The "unsigned long" and
9 * "int" types were carefully placed so as to ensure proper operation
10 * of the macros.
11 *
12 * Copyright (C) 1998, 1999, 2002 Hewlett-Packard Co
13 *	David Mosberger-Tang <davidm@hpl.hp.com>
14 */
15#include <linux/types.h>
16
17#include <asm/system.h>
18
19/*
20 * On IA-64, counter must always be volatile to ensure that that the
21 * memory accesses are ordered.
22 */
23typedef struct { volatile __s32 counter; } atomic_t;
24
25#define ATOMIC_INIT(i)		((atomic_t) { (i) })
26
27#define atomic_read(v)		((v)->counter)
28#define atomic_set(v,i)		(((v)->counter) = (i))
29
30static __inline__ int
31ia64_atomic_add (int i, atomic_t *v)
32{
33	__s32 old, new;
34	CMPXCHG_BUGCHECK_DECL
35
36	do {
37		CMPXCHG_BUGCHECK(v);
38		old = atomic_read(v);
39		new = old + i;
40	} while (ia64_cmpxchg("acq", v, old, old + i, sizeof(atomic_t)) != old);
41	return new;
42}
43
44static __inline__ int
45ia64_atomic_sub (int i, atomic_t *v)
46{
47	__s32 old, new;
48	CMPXCHG_BUGCHECK_DECL
49
50	do {
51		CMPXCHG_BUGCHECK(v);
52		old = atomic_read(v);
53		new = old - i;
54	} while (ia64_cmpxchg("acq", v, old, new, sizeof(atomic_t)) != old);
55	return new;
56}
57
58/*
59 * Atomically add I to V and return TRUE if the resulting value is
60 * negative.
61 */
62static __inline__ int
63atomic_add_negative (int i, atomic_t *v)
64{
65	return ia64_atomic_add(i, v) < 0;
66}
67
68#define atomic_add_return(i,v)						\
69	((__builtin_constant_p(i) &&					\
70	  (   (i ==  1) || (i ==  4) || (i ==  8) || (i ==  16)		\
71	   || (i == -1) || (i == -4) || (i == -8) || (i == -16)))	\
72	 ? ia64_fetch_and_add(i, &(v)->counter)				\
73	 : ia64_atomic_add(i, v))
74
75#define atomic_sub_return(i,v)						\
76	((__builtin_constant_p(i) &&					\
77	  (   (i ==  1) || (i ==  4) || (i ==  8) || (i ==  16)		\
78	   || (i == -1) || (i == -4) || (i == -8) || (i == -16)))	\
79	 ? ia64_fetch_and_add(-(i), &(v)->counter)			\
80	 : ia64_atomic_sub(i, v))
81
82#define atomic_dec_return(v)		atomic_sub_return(1, (v))
83#define atomic_inc_return(v)		atomic_add_return(1, (v))
84
85#define atomic_sub_and_test(i,v)	(atomic_sub_return((i), (v)) == 0)
86#define atomic_dec_and_test(v)		(atomic_sub_return(1, (v)) == 0)
87#define atomic_inc_and_test(v)		(atomic_add_return(1, (v)) != 0)
88
89#define atomic_add(i,v)			atomic_add_return((i), (v))
90#define atomic_sub(i,v)			atomic_sub_return((i), (v))
91#define atomic_inc(v)			atomic_add(1, (v))
92#define atomic_dec(v)			atomic_sub(1, (v))
93
94/* Atomic operations are already serializing */
95#define smp_mb__before_atomic_dec()	barrier()
96#define smp_mb__after_atomic_dec()	barrier()
97#define smp_mb__before_atomic_inc()	barrier()
98#define smp_mb__after_atomic_inc()	barrier()
99
100#endif /* _ASM_IA64_ATOMIC_H */
101