xref: /openbmc/linux/arch/alpha/include/asm/spinlock.h (revision 82003e04) 
1 #ifndef _ALPHA_SPINLOCK_H
2 #define _ALPHA_SPINLOCK_H
3 
4 #include <linux/kernel.h>
5 #include <asm/current.h>
6 #include <asm/barrier.h>
7 #include <asm/processor.h>
8 
9 /*
10  * Simple spin lock operations.  There are two variants, one clears IRQ's
11  * on the local processor, one does not.
12  *
13  * We make no fairness assumptions. They have a cost.
14  */
15 
16 #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
17 #define arch_spin_is_locked(x)	((x)->lock != 0)
18 
19 static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
20 {
21 	smp_cond_load_acquire(&lock->lock, !VAL);
22 }
23 
24 static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
25 {
26         return lock.lock == 0;
27 }
28 
29 static inline void arch_spin_unlock(arch_spinlock_t * lock)
30 {
31 	mb();
32 	lock->lock = 0;
33 }
34 
35 static inline void arch_spin_lock(arch_spinlock_t * lock)
36 {
37 	long tmp;
38 
39 	__asm__ __volatile__(
40 	"1:	ldl_l	%0,%1\n"
41 	"	bne	%0,2f\n"
42 	"	lda	%0,1\n"
43 	"	stl_c	%0,%1\n"
44 	"	beq	%0,2f\n"
45 	"	mb\n"
46 	".subsection 2\n"
47 	"2:	ldl	%0,%1\n"
48 	"	bne	%0,2b\n"
49 	"	br	1b\n"
50 	".previous"
51 	: "=&r" (tmp), "=m" (lock->lock)
52 	: "m"(lock->lock) : "memory");
53 }
54 
55 static inline int arch_spin_trylock(arch_spinlock_t *lock)
56 {
57 	return !test_and_set_bit(0, &lock->lock);
58 }
59 
60 /***********************************************************/
61 
62 static inline int arch_read_can_lock(arch_rwlock_t *lock)
63 {
64 	return (lock->lock & 1) == 0;
65 }
66 
67 static inline int arch_write_can_lock(arch_rwlock_t *lock)
68 {
69 	return lock->lock == 0;
70 }
71 
72 static inline void arch_read_lock(arch_rwlock_t *lock)
73 {
74 	long regx;
75 
76 	__asm__ __volatile__(
77 	"1:	ldl_l	%1,%0\n"
78 	"	blbs	%1,6f\n"
79 	"	subl	%1,2,%1\n"
80 	"	stl_c	%1,%0\n"
81 	"	beq	%1,6f\n"
82 	"	mb\n"
83 	".subsection 2\n"
84 	"6:	ldl	%1,%0\n"
85 	"	blbs	%1,6b\n"
86 	"	br	1b\n"
87 	".previous"
88 	: "=m" (*lock), "=&r" (regx)
89 	: "m" (*lock) : "memory");
90 }
91 
92 static inline void arch_write_lock(arch_rwlock_t *lock)
93 {
94 	long regx;
95 
96 	__asm__ __volatile__(
97 	"1:	ldl_l	%1,%0\n"
98 	"	bne	%1,6f\n"
99 	"	lda	%1,1\n"
100 	"	stl_c	%1,%0\n"
101 	"	beq	%1,6f\n"
102 	"	mb\n"
103 	".subsection 2\n"
104 	"6:	ldl	%1,%0\n"
105 	"	bne	%1,6b\n"
106 	"	br	1b\n"
107 	".previous"
108 	: "=m" (*lock), "=&r" (regx)
109 	: "m" (*lock) : "memory");
110 }
111 
112 static inline int arch_read_trylock(arch_rwlock_t * lock)
113 {
114 	long regx;
115 	int success;
116 
117 	__asm__ __volatile__(
118 	"1:	ldl_l	%1,%0\n"
119 	"	lda	%2,0\n"
120 	"	blbs	%1,2f\n"
121 	"	subl	%1,2,%2\n"
122 	"	stl_c	%2,%0\n"
123 	"	beq	%2,6f\n"
124 	"2:	mb\n"
125 	".subsection 2\n"
126 	"6:	br	1b\n"
127 	".previous"
128 	: "=m" (*lock), "=&r" (regx), "=&r" (success)
129 	: "m" (*lock) : "memory");
130 
131 	return success;
132 }
133 
134 static inline int arch_write_trylock(arch_rwlock_t * lock)
135 {
136 	long regx;
137 	int success;
138 
139 	__asm__ __volatile__(
140 	"1:	ldl_l	%1,%0\n"
141 	"	lda	%2,0\n"
142 	"	bne	%1,2f\n"
143 	"	lda	%2,1\n"
144 	"	stl_c	%2,%0\n"
145 	"	beq	%2,6f\n"
146 	"2:	mb\n"
147 	".subsection 2\n"
148 	"6:	br	1b\n"
149 	".previous"
150 	: "=m" (*lock), "=&r" (regx), "=&r" (success)
151 	: "m" (*lock) : "memory");
152 
153 	return success;
154 }
155 
156 static inline void arch_read_unlock(arch_rwlock_t * lock)
157 {
158 	long regx;
159 	__asm__ __volatile__(
160 	"	mb\n"
161 	"1:	ldl_l	%1,%0\n"
162 	"	addl	%1,2,%1\n"
163 	"	stl_c	%1,%0\n"
164 	"	beq	%1,6f\n"
165 	".subsection 2\n"
166 	"6:	br	1b\n"
167 	".previous"
168 	: "=m" (*lock), "=&r" (regx)
169 	: "m" (*lock) : "memory");
170 }
171 
172 static inline void arch_write_unlock(arch_rwlock_t * lock)
173 {
174 	mb();
175 	lock->lock = 0;
176 }
177 
178 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
179 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
180 
181 #endif /* _ALPHA_SPINLOCK_H */
182