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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _ASM_PARISC_ATOMIC_H_
2#define _ASM_PARISC_ATOMIC_H_
3
4#include <linux/config.h>
5#include <asm/system.h>
6/* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>. */
7
8/*
9 * Atomic operations that C can't guarantee us. Useful for
10 * resource counting etc..
11 *
12 * And probably incredibly slow on parisc. OTOH, we don't
13 * have to write any serious assembly. prumpf
14 */
15
16#ifdef CONFIG_SMP
17#include <asm/spinlock.h>
18#include <asm/cache.h> /* we use L1_CACHE_BYTES */
19
20/* Use an array of spinlocks for our atomic_ts.
21 * Hash function to index into a different SPINLOCK.
22 * Since "a" is usually an address, use one spinlock per cacheline.
23 */
24# define ATOMIC_HASH_SIZE 4
25# define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) a)/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ]))
26
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070027extern raw_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070029/* Can't use raw_spin_lock_irq because of #include problems, so
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 * this is the substitute */
31#define _atomic_spin_lock_irqsave(l,f) do { \
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070032 raw_spinlock_t *s = ATOMIC_HASH(l); \
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 local_irq_save(f); \
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070034 __raw_spin_lock(s); \
Linus Torvalds1da177e2005-04-16 15:20:36 -070035} while(0)
36
37#define _atomic_spin_unlock_irqrestore(l,f) do { \
Ingo Molnarfb1c8f92005-09-10 00:25:56 -070038 raw_spinlock_t *s = ATOMIC_HASH(l); \
39 __raw_spin_unlock(s); \
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 local_irq_restore(f); \
41} while(0)
42
43
44#else
45# define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0)
46# define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0)
47#endif
48
49/* Note that we need not lock read accesses - aligned word writes/reads
50 * are atomic, so a reader never sees unconsistent values.
51 *
52 * Cache-line alignment would conflict with, for example, linux/module.h
53 */
54
55typedef struct { volatile int counter; } atomic_t;
56
57
58/* This should get optimized out since it's never called.
59** Or get a link error if xchg is used "wrong".
60*/
61extern void __xchg_called_with_bad_pointer(void);
62
63
64/* __xchg32/64 defined in arch/parisc/lib/bitops.c */
65extern unsigned long __xchg8(char, char *);
66extern unsigned long __xchg32(int, int *);
67#ifdef __LP64__
68extern unsigned long __xchg64(unsigned long, unsigned long *);
69#endif
70
71/* optimizer better get rid of switch since size is a constant */
72static __inline__ unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
73 int size)
74{
75
76 switch(size) {
77#ifdef __LP64__
78 case 8: return __xchg64(x,(unsigned long *) ptr);
79#endif
80 case 4: return __xchg32((int) x, (int *) ptr);
81 case 1: return __xchg8((char) x, (char *) ptr);
82 }
83 __xchg_called_with_bad_pointer();
84 return x;
85}
86
87
88/*
89** REVISIT - Abandoned use of LDCW in xchg() for now:
90** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
91** o and while we are at it, could __LP64__ code use LDCD too?
92**
93** if (__builtin_constant_p(x) && (x == NULL))
94** if (((unsigned long)p & 0xf) == 0)
95** return __ldcw(p);
96*/
97#define xchg(ptr,x) \
98 ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
99
100
101#define __HAVE_ARCH_CMPXCHG 1
102
103/* bug catcher for when unsupported size is used - won't link */
104extern void __cmpxchg_called_with_bad_pointer(void);
105
106/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
107extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old, unsigned int new_);
108extern unsigned long __cmpxchg_u64(volatile unsigned long *ptr, unsigned long old, unsigned long new_);
109
110/* don't worry...optimizer will get rid of most of this */
111static __inline__ unsigned long
112__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
113{
114 switch(size) {
115#ifdef __LP64__
116 case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_);
117#endif
118 case 4: return __cmpxchg_u32((unsigned int *)ptr, (unsigned int) old, (unsigned int) new_);
119 }
120 __cmpxchg_called_with_bad_pointer();
121 return old;
122}
123
124#define cmpxchg(ptr,o,n) \
125 ({ \
126 __typeof__(*(ptr)) _o_ = (o); \
127 __typeof__(*(ptr)) _n_ = (n); \
128 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
129 (unsigned long)_n_, sizeof(*(ptr))); \
130 })
131
132
133
134/* It's possible to reduce all atomic operations to either
135 * __atomic_add_return, atomic_set and atomic_read (the latter
136 * is there only for consistency).
137 */
138
139static __inline__ int __atomic_add_return(int i, atomic_t *v)
140{
141 int ret;
142 unsigned long flags;
143 _atomic_spin_lock_irqsave(v, flags);
144
145 ret = (v->counter += i);
146
147 _atomic_spin_unlock_irqrestore(v, flags);
148 return ret;
149}
150
151static __inline__ void atomic_set(atomic_t *v, int i)
152{
153 unsigned long flags;
154 _atomic_spin_lock_irqsave(v, flags);
155
156 v->counter = i;
157
158 _atomic_spin_unlock_irqrestore(v, flags);
159}
160
161static __inline__ int atomic_read(const atomic_t *v)
162{
163 return v->counter;
164}
165
166/* exported interface */
Nick Piggin4a6dae62005-11-13 16:07:24 -0800167#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
Ingo Molnarffbf6702006-01-09 15:59:17 -0800168#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169
Nick Piggin8426e1f2005-11-13 16:07:25 -0800170/**
171 * atomic_add_unless - add unless the number is a given value
172 * @v: pointer of type atomic_t
173 * @a: the amount to add to v...
174 * @u: ...unless v is equal to u.
175 *
176 * Atomically adds @a to @v, so long as it was not @u.
177 * Returns non-zero if @v was not @u, and zero otherwise.
178 */
179#define atomic_add_unless(v, a, u) \
180({ \
181 int c, old; \
182 c = atomic_read(v); \
183 while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
184 c = old; \
185 c != (u); \
186})
187#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
188
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189#define atomic_add(i,v) ((void)(__atomic_add_return( ((int)i),(v))))
190#define atomic_sub(i,v) ((void)(__atomic_add_return(-((int)i),(v))))
191#define atomic_inc(v) ((void)(__atomic_add_return( 1,(v))))
192#define atomic_dec(v) ((void)(__atomic_add_return( -1,(v))))
193
194#define atomic_add_return(i,v) (__atomic_add_return( ((int)i),(v)))
195#define atomic_sub_return(i,v) (__atomic_add_return(-((int)i),(v)))
196#define atomic_inc_return(v) (__atomic_add_return( 1,(v)))
197#define atomic_dec_return(v) (__atomic_add_return( -1,(v)))
198
199#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
200
201/*
202 * atomic_inc_and_test - increment and test
203 * @v: pointer of type atomic_t
204 *
205 * Atomically increments @v by 1
206 * and returns true if the result is zero, or false for all
207 * other cases.
208 */
209#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
210
211#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
212
213#define ATOMIC_INIT(i) { (i) }
214
215#define smp_mb__before_atomic_dec() smp_mb()
216#define smp_mb__after_atomic_dec() smp_mb()
217#define smp_mb__before_atomic_inc() smp_mb()
218#define smp_mb__after_atomic_inc() smp_mb()
219
Christoph Lameterd3cb4872006-01-06 00:11:20 -0800220#include <asm-generic/atomic.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221#endif