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[hh.org.git] / include / asm-mips / spinlock.h
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1 /*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
6 * Copyright (C) 1999, 2000 by Ralf Baechle
7 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8 */
9 #ifndef _ASM_SPINLOCK_H
10 #define _ASM_SPINLOCK_H
12 #include <asm/war.h>
15 * Your basic SMP spinlocks, allowing only a single CPU anywhere
18 #define __raw_spin_is_locked(x) ((x)->lock != 0)
19 #define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
20 #define __raw_spin_unlock_wait(x) \
21 do { cpu_relax(); } while ((x)->lock)
24 * Simple spin lock operations. There are two variants, one clears IRQ's
25 * on the local processor, one does not.
27 * We make no fairness assumptions. They have a cost.
30 static inline void __raw_spin_lock(raw_spinlock_t *lock)
32 unsigned int tmp;
34 if (R10000_LLSC_WAR) {
35 __asm__ __volatile__(
36 " .set noreorder # __raw_spin_lock \n"
37 "1: ll %1, %2 \n"
38 " bnez %1, 1b \n"
39 " li %1, 1 \n"
40 " sc %1, %0 \n"
41 " beqzl %1, 1b \n"
42 " nop \n"
43 " sync \n"
44 " .set reorder \n"
45 : "=m" (lock->lock), "=&r" (tmp)
46 : "m" (lock->lock)
47 : "memory");
48 } else {
49 __asm__ __volatile__(
50 " .set noreorder # __raw_spin_lock \n"
51 "1: ll %1, %2 \n"
52 " bnez %1, 1b \n"
53 " li %1, 1 \n"
54 " sc %1, %0 \n"
55 " beqz %1, 1b \n"
56 " sync \n"
57 " .set reorder \n"
58 : "=m" (lock->lock), "=&r" (tmp)
59 : "m" (lock->lock)
60 : "memory");
64 static inline void __raw_spin_unlock(raw_spinlock_t *lock)
66 __asm__ __volatile__(
67 " .set noreorder # __raw_spin_unlock \n"
68 " sync \n"
69 " sw $0, %0 \n"
70 " .set\treorder \n"
71 : "=m" (lock->lock)
72 : "m" (lock->lock)
73 : "memory");
76 static inline unsigned int __raw_spin_trylock(raw_spinlock_t *lock)
78 unsigned int temp, res;
80 if (R10000_LLSC_WAR) {
81 __asm__ __volatile__(
82 " .set noreorder # __raw_spin_trylock \n"
83 "1: ll %0, %3 \n"
84 " ori %2, %0, 1 \n"
85 " sc %2, %1 \n"
86 " beqzl %2, 1b \n"
87 " nop \n"
88 " andi %2, %0, 1 \n"
89 " sync \n"
90 " .set reorder"
91 : "=&r" (temp), "=m" (lock->lock), "=&r" (res)
92 : "m" (lock->lock)
93 : "memory");
94 } else {
95 __asm__ __volatile__(
96 " .set noreorder # __raw_spin_trylock \n"
97 "1: ll %0, %3 \n"
98 " ori %2, %0, 1 \n"
99 " sc %2, %1 \n"
100 " beqz %2, 1b \n"
101 " andi %2, %0, 1 \n"
102 " sync \n"
103 " .set reorder"
104 : "=&r" (temp), "=m" (lock->lock), "=&r" (res)
105 : "m" (lock->lock)
106 : "memory");
109 return res == 0;
113 * Read-write spinlocks, allowing multiple readers but only one writer.
115 * NOTE! it is quite common to have readers in interrupts but no interrupt
116 * writers. For those circumstances we can "mix" irq-safe locks - any writer
117 * needs to get a irq-safe write-lock, but readers can get non-irqsafe
118 * read-locks.
122 * read_can_lock - would read_trylock() succeed?
123 * @lock: the rwlock in question.
125 #define __raw_read_can_lock(rw) ((rw)->lock >= 0)
128 * write_can_lock - would write_trylock() succeed?
129 * @lock: the rwlock in question.
131 #define __raw_write_can_lock(rw) (!(rw)->lock)
133 static inline void __raw_read_lock(raw_rwlock_t *rw)
135 unsigned int tmp;
137 if (R10000_LLSC_WAR) {
138 __asm__ __volatile__(
139 " .set noreorder # __raw_read_lock \n"
140 "1: ll %1, %2 \n"
141 " bltz %1, 1b \n"
142 " addu %1, 1 \n"
143 " sc %1, %0 \n"
144 " beqzl %1, 1b \n"
145 " nop \n"
146 " sync \n"
147 " .set reorder \n"
148 : "=m" (rw->lock), "=&r" (tmp)
149 : "m" (rw->lock)
150 : "memory");
151 } else {
152 __asm__ __volatile__(
153 " .set noreorder # __raw_read_lock \n"
154 "1: ll %1, %2 \n"
155 " bltz %1, 1b \n"
156 " addu %1, 1 \n"
157 " sc %1, %0 \n"
158 " beqz %1, 1b \n"
159 " sync \n"
160 " .set reorder \n"
161 : "=m" (rw->lock), "=&r" (tmp)
162 : "m" (rw->lock)
163 : "memory");
167 /* Note the use of sub, not subu which will make the kernel die with an
168 overflow exception if we ever try to unlock an rwlock that is already
169 unlocked or is being held by a writer. */
170 static inline void __raw_read_unlock(raw_rwlock_t *rw)
172 unsigned int tmp;
174 if (R10000_LLSC_WAR) {
175 __asm__ __volatile__(
176 "1: ll %1, %2 # __raw_read_unlock \n"
177 " sub %1, 1 \n"
178 " sc %1, %0 \n"
179 " beqzl %1, 1b \n"
180 " sync \n"
181 : "=m" (rw->lock), "=&r" (tmp)
182 : "m" (rw->lock)
183 : "memory");
184 } else {
185 __asm__ __volatile__(
186 " .set noreorder # __raw_read_unlock \n"
187 "1: ll %1, %2 \n"
188 " sub %1, 1 \n"
189 " sc %1, %0 \n"
190 " beqz %1, 1b \n"
191 " sync \n"
192 " .set reorder \n"
193 : "=m" (rw->lock), "=&r" (tmp)
194 : "m" (rw->lock)
195 : "memory");
199 static inline void __raw_write_lock(raw_rwlock_t *rw)
201 unsigned int tmp;
203 if (R10000_LLSC_WAR) {
204 __asm__ __volatile__(
205 " .set noreorder # __raw_write_lock \n"
206 "1: ll %1, %2 \n"
207 " bnez %1, 1b \n"
208 " lui %1, 0x8000 \n"
209 " sc %1, %0 \n"
210 " beqzl %1, 1b \n"
211 " sync \n"
212 " .set reorder \n"
213 : "=m" (rw->lock), "=&r" (tmp)
214 : "m" (rw->lock)
215 : "memory");
216 } else {
217 __asm__ __volatile__(
218 " .set noreorder # __raw_write_lock \n"
219 "1: ll %1, %2 \n"
220 " bnez %1, 1b \n"
221 " lui %1, 0x8000 \n"
222 " sc %1, %0 \n"
223 " beqz %1, 1b \n"
224 " sync \n"
225 " .set reorder \n"
226 : "=m" (rw->lock), "=&r" (tmp)
227 : "m" (rw->lock)
228 : "memory");
232 static inline void __raw_write_unlock(raw_rwlock_t *rw)
234 __asm__ __volatile__(
235 " sync # __raw_write_unlock \n"
236 " sw $0, %0 \n"
237 : "=m" (rw->lock)
238 : "m" (rw->lock)
239 : "memory");
242 static inline int __raw_read_trylock(raw_rwlock_t *rw)
244 unsigned int tmp;
245 int ret;
247 if (R10000_LLSC_WAR) {
248 __asm__ __volatile__(
249 " .set noreorder # __raw_read_trylock \n"
250 " li %2, 0 \n"
251 "1: ll %1, %3 \n"
252 " bnez %1, 2f \n"
253 " addu %1, 1 \n"
254 " sc %1, %0 \n"
255 " beqzl %1, 1b \n"
256 " .set reorder \n"
257 #ifdef CONFIG_SMP
258 " sync \n"
259 #endif
260 " li %2, 1 \n"
261 "2: \n"
262 : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret)
263 : "m" (rw->lock)
264 : "memory");
265 } else {
266 __asm__ __volatile__(
267 " .set noreorder # __raw_read_trylock \n"
268 " li %2, 0 \n"
269 "1: ll %1, %3 \n"
270 " bnez %1, 2f \n"
271 " addu %1, 1 \n"
272 " sc %1, %0 \n"
273 " beqz %1, 1b \n"
274 " .set reorder \n"
275 #ifdef CONFIG_SMP
276 " sync \n"
277 #endif
278 " li %2, 1 \n"
279 "2: \n"
280 : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret)
281 : "m" (rw->lock)
282 : "memory");
285 return ret;
288 static inline int __raw_write_trylock(raw_rwlock_t *rw)
290 unsigned int tmp;
291 int ret;
293 if (R10000_LLSC_WAR) {
294 __asm__ __volatile__(
295 " .set noreorder # __raw_write_trylock \n"
296 " li %2, 0 \n"
297 "1: ll %1, %3 \n"
298 " bnez %1, 2f \n"
299 " lui %1, 0x8000 \n"
300 " sc %1, %0 \n"
301 " beqzl %1, 1b \n"
302 " sync \n"
303 " li %2, 1 \n"
304 " .set reorder \n"
305 "2: \n"
306 : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret)
307 : "m" (rw->lock)
308 : "memory");
309 } else {
310 __asm__ __volatile__(
311 " .set noreorder # __raw_write_trylock \n"
312 " li %2, 0 \n"
313 "1: ll %1, %3 \n"
314 " bnez %1, 2f \n"
315 " lui %1, 0x8000 \n"
316 " sc %1, %0 \n"
317 " beqz %1, 1b \n"
318 " sync \n"
319 " li %2, 1 \n"
320 " .set reorder \n"
321 "2: \n"
322 : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret)
323 : "m" (rw->lock)
324 : "memory");
327 return ret;
331 #define _raw_spin_relax(lock) cpu_relax()
332 #define _raw_read_relax(lock) cpu_relax()
333 #define _raw_write_relax(lock) cpu_relax()
335 #endif /* _ASM_SPINLOCK_H */