xref: /openbmc/u-boot/arch/x86/include/asm/atomic.h (revision 20c700f8)
1 #ifndef _ASM_X86_ATOMIC_H
2 #define _ASM_X86_ATOMIC_H
3 
4 #include <linux/compiler.h>
5 #include <linux/types.h>
6 #include <asm/processor.h>
7 
8 typedef struct { volatile int counter; } atomic_t;
9 
10 /*
11  * Atomic operations that C can't guarantee us.  Useful for
12  * resource counting etc..
13  */
14 
15 #define ATOMIC_INIT(i)	{ (i) }
16 
17 /**
18  * atomic_read - read atomic variable
19  * @v: pointer of type atomic_t
20  *
21  * Atomically reads the value of @v.
22  */
23 static inline int atomic_read(const atomic_t *v)
24 {
25 	return ACCESS_ONCE((v)->counter);
26 }
27 
28 /**
29  * atomic_set - set atomic variable
30  * @v: pointer of type atomic_t
31  * @i: required value
32  *
33  * Atomically sets the value of @v to @i.
34  */
35 static inline void atomic_set(atomic_t *v, int i)
36 {
37 	v->counter = i;
38 }
39 
40 /**
41  * atomic_add - add integer to atomic variable
42  * @i: integer value to add
43  * @v: pointer of type atomic_t
44  *
45  * Atomically adds @i to @v.
46  */
47 static inline void atomic_add(int i, atomic_t *v)
48 {
49 	asm volatile(LOCK_PREFIX "addl %1,%0"
50 		     : "+m" (v->counter)
51 		     : "ir" (i));
52 }
53 
54 /**
55  * atomic_sub - subtract integer from atomic variable
56  * @i: integer value to subtract
57  * @v: pointer of type atomic_t
58  *
59  * Atomically subtracts @i from @v.
60  */
61 static inline void atomic_sub(int i, atomic_t *v)
62 {
63 	asm volatile(LOCK_PREFIX "subl %1,%0"
64 		     : "+m" (v->counter)
65 		     : "ir" (i));
66 }
67 
68 /**
69  * atomic_inc - increment atomic variable
70  * @v: pointer of type atomic_t
71  *
72  * Atomically increments @v by 1.
73  */
74 static inline void atomic_inc(atomic_t *v)
75 {
76 	asm volatile(LOCK_PREFIX "incl %0"
77 		     : "+m" (v->counter));
78 }
79 
80 /**
81  * atomic_dec - decrement atomic variable
82  * @v: pointer of type atomic_t
83  *
84  * Atomically decrements @v by 1.
85  */
86 static inline void atomic_dec(atomic_t *v)
87 {
88 	asm volatile(LOCK_PREFIX "decl %0"
89 		     : "+m" (v->counter));
90 }
91 
92 /**
93  * atomic_inc_short - increment of a short integer
94  * @v: pointer to type int
95  *
96  * Atomically adds 1 to @v
97  * Returns the new value of @u
98  */
99 static inline short int atomic_inc_short(short int *v)
100 {
101 	asm(LOCK_PREFIX "addw $1, %0" : "+m" (*v));
102 	return *v;
103 }
104 
105 /* These are x86-specific, used by some header files */
106 #define atomic_clear_mask(mask, addr)				\
107 	asm volatile(LOCK_PREFIX "andl %0,%1"			\
108 		     : : "r" (~(mask)), "m" (*(addr)) : "memory")
109 
110 #define atomic_set_mask(mask, addr)				\
111 	asm volatile(LOCK_PREFIX "orl %0,%1"			\
112 		     : : "r" ((unsigned)(mask)), "m" (*(addr))	\
113 		     : "memory")
114 
115 #endif /* _ASM_X86_ATOMIC_H */
116