1 /* SPDX-License-Identifier: GPL-2.0
2 *
3 * include/asm-sh/spinlock-llsc.h
4 *
5 * Copyright (C) 2002, 2003 Paul Mundt
6 * Copyright (C) 2006, 2007 Akio Idehara
7 */
8 #ifndef __ASM_SH_SPINLOCK_LLSC_H
9 #define __ASM_SH_SPINLOCK_LLSC_H
10
11 #include <asm/barrier.h>
12 #include <asm/processor.h>
13
14 /*
15 * Your basic SMP spinlocks, allowing only a single CPU anywhere
16 */
17
18 #define arch_spin_is_locked(x) ((x)->lock <= 0)
19
20 /*
21 * Simple spin lock operations. There are two variants, one clears IRQ's
22 * on the local processor, one does not.
23 *
24 * We make no fairness assumptions. They have a cost.
25 */
26 static inline void arch_spin_lock(arch_spinlock_t *lock)
27 {
28 unsigned long tmp;
29 unsigned long oldval;
30
31 __asm__ __volatile__ (
32 "1: \n\t"
33 "movli.l @%2, %0 ! arch_spin_lock \n\t"
34 "mov %0, %1 \n\t"
35 "mov #0, %0 \n\t"
36 "movco.l %0, @%2 \n\t"
37 "bf 1b \n\t"
38 "cmp/pl %1 \n\t"
39 "bf 1b \n\t"
40 : "=&z" (tmp), "=&r" (oldval)
41 : "r" (&lock->lock)
42 : "t", "memory"
43 );
44 }
45
46 static inline void arch_spin_unlock(arch_spinlock_t *lock)
47 {
48 unsigned long tmp;
49
50 /* This could be optimised with ARCH_HAS_MMIOWB */
51 mmiowb();
52 __asm__ __volatile__ (
53 "mov #1, %0 ! arch_spin_unlock \n\t"
54 "mov.l %0, @%1 \n\t"
55 : "=&z" (tmp)
56 : "r" (&lock->lock)
57 : "t", "memory"
58 );
59 }
60
61 static inline int arch_spin_trylock(arch_spinlock_t *lock)
62 {
63 unsigned long tmp, oldval;
64
65 __asm__ __volatile__ (
66 "1: \n\t"
67 "movli.l @%2, %0 ! arch_spin_trylock \n\t"
68 "mov %0, %1 \n\t"
69 "mov #0, %0 \n\t"
70 "movco.l %0, @%2 \n\t"
71 "bf 1b \n\t"
72 "synco \n\t"
73 : "=&z" (tmp), "=&r" (oldval)
74 : "r" (&lock->lock)
75 : "t", "memory"
76 );
77
78 return oldval;
79 }
80
81 /*
82 * Read-write spinlocks, allowing multiple readers but only one writer.
83 *
84 * NOTE! it is quite common to have readers in interrupts but no interrupt
85 * writers. For those circumstances we can "mix" irq-safe locks - any writer
86 * needs to get a irq-safe write-lock, but readers can get non-irqsafe
87 * read-locks.
88 */
89
90 static inline void arch_read_lock(arch_rwlock_t *rw)
91 {
92 unsigned long tmp;
93
94 __asm__ __volatile__ (
95 "1: \n\t"
96 "movli.l @%1, %0 ! arch_read_lock \n\t"
97 "cmp/pl %0 \n\t"
98 "bf 1b \n\t"
99 "add #-1, %0 \n\t"
100 "movco.l %0, @%1 \n\t"
101 "bf 1b \n\t"
102 : "=&z" (tmp)
103 : "r" (&rw->lock)
104 : "t", "memory"
105 );
106 }
107
108 static inline void arch_read_unlock(arch_rwlock_t *rw)
109 {
110 unsigned long tmp;
111
112 __asm__ __volatile__ (
113 "1: \n\t"
114 "movli.l @%1, %0 ! arch_read_unlock \n\t"
115 "add #1, %0 \n\t"
116 "movco.l %0, @%1 \n\t"
117 "bf 1b \n\t"
118 : "=&z" (tmp)
119 : "r" (&rw->lock)
120 : "t", "memory"
121 );
122 }
123
124 static inline void arch_write_lock(arch_rwlock_t *rw)
125 {
126 unsigned long tmp;
127
128 __asm__ __volatile__ (
129 "1: \n\t"
130 "movli.l @%1, %0 ! arch_write_lock \n\t"
131 "cmp/hs %2, %0 \n\t"
132 "bf 1b \n\t"
133 "sub %2, %0 \n\t"
134 "movco.l %0, @%1 \n\t"
135 "bf 1b \n\t"
136 : "=&z" (tmp)
137 : "r" (&rw->lock), "r" (RW_LOCK_BIAS)
138 : "t", "memory"
139 );
140 }
141
142 static inline void arch_write_unlock(arch_rwlock_t *rw)
143 {
144 __asm__ __volatile__ (
145 "mov.l %1, @%0 ! arch_write_unlock \n\t"
146 :
147 : "r" (&rw->lock), "r" (RW_LOCK_BIAS)
148 : "t", "memory"
149 );
150 }
151
152 static inline int arch_read_trylock(arch_rwlock_t *rw)
153 {
154 unsigned long tmp, oldval;
155
156 __asm__ __volatile__ (
157 "1: \n\t"
158 "movli.l @%2, %0 ! arch_read_trylock \n\t"
159 "mov %0, %1 \n\t"
160 "cmp/pl %0 \n\t"
161 "bf 2f \n\t"
162 "add #-1, %0 \n\t"
163 "movco.l %0, @%2 \n\t"
164 "bf 1b \n\t"
165 "2: \n\t"
166 "synco \n\t"
167 : "=&z" (tmp), "=&r" (oldval)
168 : "r" (&rw->lock)
169 : "t", "memory"
170 );
171
172 return (oldval > 0);
173 }
174
175 static inline int arch_write_trylock(arch_rwlock_t *rw)
176 {
177 unsigned long tmp, oldval;
178
179 __asm__ __volatile__ (
180 "1: \n\t"
181 "movli.l @%2, %0 ! arch_write_trylock \n\t"
182 "mov %0, %1 \n\t"
183 "cmp/hs %3, %0 \n\t"
184 "bf 2f \n\t"
185 "sub %3, %0 \n\t"
186 "2: \n\t"
187 "movco.l %0, @%2 \n\t"
188 "bf 1b \n\t"
189 "synco \n\t"
190 : "=&z" (tmp), "=&r" (oldval)
191 : "r" (&rw->lock), "r" (RW_LOCK_BIAS)
192 : "t", "memory"
193 );
194
195 return (oldval > (RW_LOCK_BIAS - 1));
196 }
197
198 #endif /* __ASM_SH_SPINLOCK_LLSC_H */