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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-parisc/atomic.h
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'include/asm-parisc/atomic.h')
-rw-r--r--include/asm-parisc/atomic.h199
1 files changed, 199 insertions, 0 deletions
diff --git a/include/asm-parisc/atomic.h b/include/asm-parisc/atomic.h
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1#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
27extern spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
28
29/* Can't use _raw_spin_lock_irq because of #include problems, so
30 * this is the substitute */
31#define _atomic_spin_lock_irqsave(l,f) do { \
32 spinlock_t *s = ATOMIC_HASH(l); \
33 local_irq_save(f); \
34 _raw_spin_lock(s); \
35} while(0)
36
37#define _atomic_spin_unlock_irqrestore(l,f) do { \
38 spinlock_t *s = ATOMIC_HASH(l); \
39 _raw_spin_unlock(s); \
40 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 */
167
168#define atomic_add(i,v) ((void)(__atomic_add_return( ((int)i),(v))))
169#define atomic_sub(i,v) ((void)(__atomic_add_return(-((int)i),(v))))
170#define atomic_inc(v) ((void)(__atomic_add_return( 1,(v))))
171#define atomic_dec(v) ((void)(__atomic_add_return( -1,(v))))
172
173#define atomic_add_return(i,v) (__atomic_add_return( ((int)i),(v)))
174#define atomic_sub_return(i,v) (__atomic_add_return(-((int)i),(v)))
175#define atomic_inc_return(v) (__atomic_add_return( 1,(v)))
176#define atomic_dec_return(v) (__atomic_add_return( -1,(v)))
177
178#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
179
180/*
181 * atomic_inc_and_test - increment and test
182 * @v: pointer of type atomic_t
183 *
184 * Atomically increments @v by 1
185 * and returns true if the result is zero, or false for all
186 * other cases.
187 */
188#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
189
190#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
191
192#define ATOMIC_INIT(i) { (i) }
193
194#define smp_mb__before_atomic_dec() smp_mb()
195#define smp_mb__after_atomic_dec() smp_mb()
196#define smp_mb__before_atomic_inc() smp_mb()
197#define smp_mb__after_atomic_inc() smp_mb()
198
199#endif