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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* atomic.h: These still suck, but the I-cache hit rate is higher.
2 *
David S. Miller64d329e2007-10-27 00:17:01 -07003 * Copyright (C) 1996 David S. Miller (davem@davemloft.net)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au)
Kyle McMartin6197fe42007-05-29 02:51:13 -07005 * Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
7 * Additions by Keith M Wesolowski (wesolows@foobazco.org) based
8 * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>.
9 */
10
11#ifndef __ARCH_SPARC_ATOMIC__
12#define __ARCH_SPARC_ATOMIC__
13
Kyle McMartin6197fe42007-05-29 02:51:13 -070014#include <linux/types.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
16typedef struct { volatile int counter; } atomic_t;
17
18#ifdef __KERNEL__
19
20#define ATOMIC_INIT(i) { (i) }
21
22extern int __atomic_add_return(int, atomic_t *);
Nick Piggin4a6dae62005-11-13 16:07:24 -080023extern int atomic_cmpxchg(atomic_t *, int, int);
Ingo Molnarffbf6702006-01-09 15:59:17 -080024#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
Nick Piggin8426e1f2005-11-13 16:07:25 -080025extern int atomic_add_unless(atomic_t *, int, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070026extern void atomic_set(atomic_t *, int);
27
28#define atomic_read(v) ((v)->counter)
29
30#define atomic_add(i, v) ((void)__atomic_add_return( (int)(i), (v)))
31#define atomic_sub(i, v) ((void)__atomic_add_return(-(int)(i), (v)))
32#define atomic_inc(v) ((void)__atomic_add_return( 1, (v)))
33#define atomic_dec(v) ((void)__atomic_add_return( -1, (v)))
34
35#define atomic_add_return(i, v) (__atomic_add_return( (int)(i), (v)))
36#define atomic_sub_return(i, v) (__atomic_add_return(-(int)(i), (v)))
37#define atomic_inc_return(v) (__atomic_add_return( 1, (v)))
38#define atomic_dec_return(v) (__atomic_add_return( -1, (v)))
39
40#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
41
42/*
43 * atomic_inc_and_test - increment and test
44 * @v: pointer of type atomic_t
45 *
46 * Atomically increments @v by 1
47 * and returns true if the result is zero, or false for all
48 * other cases.
49 */
50#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
51
52#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
53#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)
54
Nick Piggin8426e1f2005-11-13 16:07:25 -080055#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
56
Linus Torvalds1da177e2005-04-16 15:20:36 -070057/* This is the old 24-bit implementation. It's still used internally
58 * by some sparc-specific code, notably the semaphore implementation.
59 */
60typedef struct { volatile int counter; } atomic24_t;
61
62#ifndef CONFIG_SMP
63
64#define ATOMIC24_INIT(i) { (i) }
65#define atomic24_read(v) ((v)->counter)
66#define atomic24_set(v, i) (((v)->counter) = i)
67
68#else
69/* We do the bulk of the actual work out of line in two common
70 * routines in assembler, see arch/sparc/lib/atomic.S for the
71 * "fun" details.
72 *
73 * For SMP the trick is you embed the spin lock byte within
74 * the word, use the low byte so signedness is easily retained
75 * via a quick arithmetic shift. It looks like this:
76 *
77 * ----------------------------------------
78 * | signed 24-bit counter value | lock | atomic_t
79 * ----------------------------------------
80 * 31 8 7 0
81 */
82
83#define ATOMIC24_INIT(i) { ((i) << 8) }
84
85static inline int atomic24_read(const atomic24_t *v)
86{
87 int ret = v->counter;
88
89 while(ret & 0xff)
90 ret = v->counter;
91
92 return ret >> 8;
93}
94
95#define atomic24_set(v, i) (((v)->counter) = ((i) << 8))
96#endif
97
98static inline int __atomic24_add(int i, atomic24_t *v)
99{
100 register volatile int *ptr asm("g1");
101 register int increment asm("g2");
102 register int tmp1 asm("g3");
103 register int tmp2 asm("g4");
104 register int tmp3 asm("g7");
105
106 ptr = &v->counter;
107 increment = i;
108
109 __asm__ __volatile__(
110 "mov %%o7, %%g4\n\t"
111 "call ___atomic24_add\n\t"
112 " add %%o7, 8, %%o7\n"
113 : "=&r" (increment), "=r" (tmp1), "=r" (tmp2), "=r" (tmp3)
114 : "0" (increment), "r" (ptr)
115 : "memory", "cc");
116
117 return increment;
118}
119
120static inline int __atomic24_sub(int i, atomic24_t *v)
121{
122 register volatile int *ptr asm("g1");
123 register int increment asm("g2");
124 register int tmp1 asm("g3");
125 register int tmp2 asm("g4");
126 register int tmp3 asm("g7");
127
128 ptr = &v->counter;
129 increment = i;
130
131 __asm__ __volatile__(
132 "mov %%o7, %%g4\n\t"
133 "call ___atomic24_sub\n\t"
134 " add %%o7, 8, %%o7\n"
135 : "=&r" (increment), "=r" (tmp1), "=r" (tmp2), "=r" (tmp3)
136 : "0" (increment), "r" (ptr)
137 : "memory", "cc");
138
139 return increment;
140}
141
142#define atomic24_add(i, v) ((void)__atomic24_add((i), (v)))
143#define atomic24_sub(i, v) ((void)__atomic24_sub((i), (v)))
144
145#define atomic24_dec_return(v) __atomic24_sub(1, (v))
146#define atomic24_inc_return(v) __atomic24_add(1, (v))
147
148#define atomic24_sub_and_test(i, v) (__atomic24_sub((i), (v)) == 0)
149#define atomic24_dec_and_test(v) (__atomic24_sub(1, (v)) == 0)
150
151#define atomic24_inc(v) ((void)__atomic24_add(1, (v)))
152#define atomic24_dec(v) ((void)__atomic24_sub(1, (v)))
153
154#define atomic24_add_negative(i, v) (__atomic24_add((i), (v)) < 0)
155
156/* Atomic operations are already serializing */
157#define smp_mb__before_atomic_dec() barrier()
158#define smp_mb__after_atomic_dec() barrier()
159#define smp_mb__before_atomic_inc() barrier()
160#define smp_mb__after_atomic_inc() barrier()
161
162#endif /* !(__KERNEL__) */
163
Christoph Lameterd3cb4872006-01-06 00:11:20 -0800164#include <asm-generic/atomic.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165#endif /* !(__ARCH_SPARC_ATOMIC__) */