1/*
2 * Atomic operations that C can't guarantee us.  Useful for
3 * resource counting etc.
4 *
5 * But use these as seldom as possible since they are slower than
6 * regular operations.
7 *
8 * Copyright (C) 2004-2006 Atmel Corporation
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14#ifndef __ASM_AVR32_CMPXCHG_H
15#define __ASM_AVR32_CMPXCHG_H
16
17#define xchg(ptr,x) \
18	((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
19
20extern void __xchg_called_with_bad_pointer(void);
21
22static inline unsigned long xchg_u32(u32 val, volatile u32 *m)
23{
24	u32 ret;
25
26	asm volatile("xchg %[ret], %[m], %[val]"
27			: [ret] "=&r"(ret), "=m"(*m)
28			: "m"(*m), [m] "r"(m), [val] "r"(val)
29			: "memory");
30	return ret;
31}
32
33static inline unsigned long __xchg(unsigned long x,
34				       volatile void *ptr,
35				       int size)
36{
37	switch(size) {
38	case 4:
39		return xchg_u32(x, ptr);
40	default:
41		__xchg_called_with_bad_pointer();
42		return x;
43	}
44}
45
46static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
47					  unsigned long new)
48{
49	__u32 ret;
50
51	asm volatile(
52		"1:	ssrf	5\n"
53		"	ld.w	%[ret], %[m]\n"
54		"	cp.w	%[ret], %[old]\n"
55		"	brne	2f\n"
56		"	stcond	%[m], %[new]\n"
57		"	brne	1b\n"
58		"2:\n"
59		: [ret] "=&r"(ret), [m] "=m"(*m)
60		: "m"(m), [old] "ir"(old), [new] "r"(new)
61		: "memory", "cc");
62	return ret;
63}
64
65extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
66        volatile int * m, unsigned long old, unsigned long new);
67#define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
68
69/* This function doesn't exist, so you'll get a linker error
70   if something tries to do an invalid cmpxchg().  */
71extern void __cmpxchg_called_with_bad_pointer(void);
72
73#define __HAVE_ARCH_CMPXCHG 1
74
75static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
76				      unsigned long new, int size)
77{
78	switch (size) {
79	case 4:
80		return __cmpxchg_u32(ptr, old, new);
81	case 8:
82		return __cmpxchg_u64(ptr, old, new);
83	}
84
85	__cmpxchg_called_with_bad_pointer();
86	return old;
87}
88
89#define cmpxchg(ptr, old, new)					\
90	((typeof(*(ptr)))__cmpxchg((ptr), (unsigned long)(old),	\
91				   (unsigned long)(new),	\
92				   sizeof(*(ptr))))
93
94#include <asm-generic/cmpxchg-local.h>
95
96static inline unsigned long __cmpxchg_local(volatile void *ptr,
97				      unsigned long old,
98				      unsigned long new, int size)
99{
100	switch (size) {
101	case 4:
102		return __cmpxchg_u32(ptr, old, new);
103	default:
104		return __cmpxchg_local_generic(ptr, old, new, size);
105	}
106
107	return old;
108}
109
110#define cmpxchg_local(ptr, old, new)					\
111	((typeof(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(old),	\
112				   (unsigned long)(new),		\
113				   sizeof(*(ptr))))
114
115#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
116
117#endif /* __ASM_AVR32_CMPXCHG_H */
118