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1da177e4 LT |
1 | #ifndef __ASM_SH_ATOMIC_H |
2 | #define __ASM_SH_ATOMIC_H | |
3 | ||
4 | /* | |
5 | * Atomic operations that C can't guarantee us. Useful for | |
6 | * resource counting etc.. | |
7 | * | |
8 | */ | |
9 | ||
10 | typedef struct { volatile int counter; } atomic_t; | |
11 | ||
12 | #define ATOMIC_INIT(i) ( (atomic_t) { (i) } ) | |
13 | ||
14 | #define atomic_read(v) ((v)->counter) | |
15 | #define atomic_set(v,i) ((v)->counter = (i)) | |
16 | ||
17 | #include <asm/system.h> | |
18 | ||
19 | /* | |
20 | * To get proper branch prediction for the main line, we must branch | |
21 | * forward to code at the end of this object's .text section, then | |
22 | * branch back to restart the operation. | |
23 | */ | |
24 | ||
25 | static __inline__ void atomic_add(int i, atomic_t * v) | |
26 | { | |
27 | unsigned long flags; | |
28 | ||
29 | local_irq_save(flags); | |
30 | *(long *)v += i; | |
31 | local_irq_restore(flags); | |
32 | } | |
33 | ||
34 | static __inline__ void atomic_sub(int i, atomic_t *v) | |
35 | { | |
36 | unsigned long flags; | |
37 | ||
38 | local_irq_save(flags); | |
39 | *(long *)v -= i; | |
40 | local_irq_restore(flags); | |
41 | } | |
42 | ||
43 | static __inline__ int atomic_add_return(int i, atomic_t * v) | |
44 | { | |
45 | unsigned long temp, flags; | |
46 | ||
47 | local_irq_save(flags); | |
48 | temp = *(long *)v; | |
49 | temp += i; | |
50 | *(long *)v = temp; | |
51 | local_irq_restore(flags); | |
52 | ||
53 | return temp; | |
54 | } | |
55 | ||
56 | #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0) | |
57 | ||
58 | static __inline__ int atomic_sub_return(int i, atomic_t * v) | |
59 | { | |
60 | unsigned long temp, flags; | |
61 | ||
62 | local_irq_save(flags); | |
63 | temp = *(long *)v; | |
64 | temp -= i; | |
65 | *(long *)v = temp; | |
66 | local_irq_restore(flags); | |
67 | ||
68 | return temp; | |
69 | } | |
70 | ||
71 | #define atomic_dec_return(v) atomic_sub_return(1,(v)) | |
72 | #define atomic_inc_return(v) atomic_add_return(1,(v)) | |
73 | ||
74 | /* | |
75 | * atomic_inc_and_test - increment and test | |
76 | * @v: pointer of type atomic_t | |
77 | * | |
78 | * Atomically increments @v by 1 | |
79 | * and returns true if the result is zero, or false for all | |
80 | * other cases. | |
81 | */ | |
82 | #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0) | |
83 | ||
84 | #define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0) | |
85 | #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0) | |
86 | ||
87 | #define atomic_inc(v) atomic_add(1,(v)) | |
88 | #define atomic_dec(v) atomic_sub(1,(v)) | |
89 | ||
90 | static __inline__ void atomic_clear_mask(unsigned int mask, atomic_t *v) | |
91 | { | |
92 | unsigned long flags; | |
93 | ||
94 | local_irq_save(flags); | |
95 | *(long *)v &= ~mask; | |
96 | local_irq_restore(flags); | |
97 | } | |
98 | ||
99 | static __inline__ void atomic_set_mask(unsigned int mask, atomic_t *v) | |
100 | { | |
101 | unsigned long flags; | |
102 | ||
103 | local_irq_save(flags); | |
104 | *(long *)v |= mask; | |
105 | local_irq_restore(flags); | |
106 | } | |
107 | ||
108 | /* Atomic operations are already serializing on SH */ | |
109 | #define smp_mb__before_atomic_dec() barrier() | |
110 | #define smp_mb__after_atomic_dec() barrier() | |
111 | #define smp_mb__before_atomic_inc() barrier() | |
112 | #define smp_mb__after_atomic_inc() barrier() | |
113 | ||
114 | #endif /* __ASM_SH_ATOMIC_H */ |