xref: /openbmc/linux/arch/alpha/include/asm/spinlock.h (revision e190bfe5) 
1 #ifndef _ALPHA_SPINLOCK_H
2 #define _ALPHA_SPINLOCK_H
3 
4 #include <asm/system.h>
5 #include <linux/kernel.h>
6 #include <asm/current.h>
7 
8 /*
9  * Simple spin lock operations.  There are two variants, one clears IRQ's
10  * on the local processor, one does not.
11  *
12  * We make no fairness assumptions. They have a cost.
13  */
14 
15 #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
16 #define arch_spin_is_locked(x)	((x)->lock != 0)
17 #define arch_spin_unlock_wait(x) \
18 		do { cpu_relax(); } while ((x)->lock)
19 
20 static inline void arch_spin_unlock(arch_spinlock_t * lock)
21 {
22 	mb();
23 	lock->lock = 0;
24 }
25 
26 static inline void arch_spin_lock(arch_spinlock_t * lock)
27 {
28 	long tmp;
29 
30 	__asm__ __volatile__(
31 	"1:	ldl_l	%0,%1\n"
32 	"	bne	%0,2f\n"
33 	"	lda	%0,1\n"
34 	"	stl_c	%0,%1\n"
35 	"	beq	%0,2f\n"
36 	"	mb\n"
37 	".subsection 2\n"
38 	"2:	ldl	%0,%1\n"
39 	"	bne	%0,2b\n"
40 	"	br	1b\n"
41 	".previous"
42 	: "=&r" (tmp), "=m" (lock->lock)
43 	: "m"(lock->lock) : "memory");
44 }
45 
46 static inline int arch_spin_trylock(arch_spinlock_t *lock)
47 {
48 	return !test_and_set_bit(0, &lock->lock);
49 }
50 
51 /***********************************************************/
52 
53 static inline int arch_read_can_lock(arch_rwlock_t *lock)
54 {
55 	return (lock->lock & 1) == 0;
56 }
57 
58 static inline int arch_write_can_lock(arch_rwlock_t *lock)
59 {
60 	return lock->lock == 0;
61 }
62 
63 static inline void arch_read_lock(arch_rwlock_t *lock)
64 {
65 	long regx;
66 
67 	__asm__ __volatile__(
68 	"1:	ldl_l	%1,%0\n"
69 	"	blbs	%1,6f\n"
70 	"	subl	%1,2,%1\n"
71 	"	stl_c	%1,%0\n"
72 	"	beq	%1,6f\n"
73 	"	mb\n"
74 	".subsection 2\n"
75 	"6:	ldl	%1,%0\n"
76 	"	blbs	%1,6b\n"
77 	"	br	1b\n"
78 	".previous"
79 	: "=m" (*lock), "=&r" (regx)
80 	: "m" (*lock) : "memory");
81 }
82 
83 static inline void arch_write_lock(arch_rwlock_t *lock)
84 {
85 	long regx;
86 
87 	__asm__ __volatile__(
88 	"1:	ldl_l	%1,%0\n"
89 	"	bne	%1,6f\n"
90 	"	lda	%1,1\n"
91 	"	stl_c	%1,%0\n"
92 	"	beq	%1,6f\n"
93 	"	mb\n"
94 	".subsection 2\n"
95 	"6:	ldl	%1,%0\n"
96 	"	bne	%1,6b\n"
97 	"	br	1b\n"
98 	".previous"
99 	: "=m" (*lock), "=&r" (regx)
100 	: "m" (*lock) : "memory");
101 }
102 
103 static inline int arch_read_trylock(arch_rwlock_t * lock)
104 {
105 	long regx;
106 	int success;
107 
108 	__asm__ __volatile__(
109 	"1:	ldl_l	%1,%0\n"
110 	"	lda	%2,0\n"
111 	"	blbs	%1,2f\n"
112 	"	subl	%1,2,%2\n"
113 	"	stl_c	%2,%0\n"
114 	"	beq	%2,6f\n"
115 	"2:	mb\n"
116 	".subsection 2\n"
117 	"6:	br	1b\n"
118 	".previous"
119 	: "=m" (*lock), "=&r" (regx), "=&r" (success)
120 	: "m" (*lock) : "memory");
121 
122 	return success;
123 }
124 
125 static inline int arch_write_trylock(arch_rwlock_t * lock)
126 {
127 	long regx;
128 	int success;
129 
130 	__asm__ __volatile__(
131 	"1:	ldl_l	%1,%0\n"
132 	"	lda	%2,0\n"
133 	"	bne	%1,2f\n"
134 	"	lda	%2,1\n"
135 	"	stl_c	%2,%0\n"
136 	"	beq	%2,6f\n"
137 	"2:	mb\n"
138 	".subsection 2\n"
139 	"6:	br	1b\n"
140 	".previous"
141 	: "=m" (*lock), "=&r" (regx), "=&r" (success)
142 	: "m" (*lock) : "memory");
143 
144 	return success;
145 }
146 
147 static inline void arch_read_unlock(arch_rwlock_t * lock)
148 {
149 	long regx;
150 	__asm__ __volatile__(
151 	"	mb\n"
152 	"1:	ldl_l	%1,%0\n"
153 	"	addl	%1,2,%1\n"
154 	"	stl_c	%1,%0\n"
155 	"	beq	%1,6f\n"
156 	".subsection 2\n"
157 	"6:	br	1b\n"
158 	".previous"
159 	: "=m" (*lock), "=&r" (regx)
160 	: "m" (*lock) : "memory");
161 }
162 
163 static inline void arch_write_unlock(arch_rwlock_t * lock)
164 {
165 	mb();
166 	lock->lock = 0;
167 }
168 
169 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
170 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
171 
172 #define arch_spin_relax(lock)	cpu_relax()
173 #define arch_read_relax(lock)	cpu_relax()
174 #define arch_write_relax(lock)	cpu_relax()
175 
176 #endif /* _ALPHA_SPINLOCK_H */
177