1 #ifndef _ASM_M32R_SPINLOCK_H
2 #define _ASM_M32R_SPINLOCK_H
3
4 /*
5 * linux/include/asm-m32r/spinlock.h
6 *
7 * M32R version:
8 * Copyright (C) 2001, 2002 Hitoshi Yamamoto
9 * Copyright (C) 2004 Hirokazu Takata <takata at linux-m32r.org>
10 */
11
12 #include <linux/compiler.h>
13 #include <linux/atomic.h>
14 #include <asm/page.h>
15
16 /*
17 * Your basic SMP spinlocks, allowing only a single CPU anywhere
18 *
19 * (the type definitions are in asm/spinlock_types.h)
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
27 #define arch_spin_is_locked(x) (*(volatile int *)(&(x)->slock) <= 0)
28 #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
29 #define arch_spin_unlock_wait(x) \
30 do { cpu_relax(); } while (arch_spin_is_locked(x))
31
32 /**
33 * arch_spin_trylock - Try spin lock and return a result
34 * @lock: Pointer to the lock variable
35 *
36 * arch_spin_trylock() tries to get the lock and returns a result.
37 * On the m32r, the result value is 1 (= Success) or 0 (= Failure).
38 */
arch_spin_trylock(arch_spinlock_t * lock)39 static inline int arch_spin_trylock(arch_spinlock_t *lock)
40 {
41 int oldval;
42 unsigned long tmp1, tmp2;
43
44 /*
45 * lock->slock : =1 : unlock
46 * : <=0 : lock
47 * {
48 * oldval = lock->slock; <--+ need atomic operation
49 * lock->slock = 0; <--+
50 * }
51 */
52 __asm__ __volatile__ (
53 "# arch_spin_trylock \n\t"
54 "ldi %1, #0; \n\t"
55 "mvfc %2, psw; \n\t"
56 "clrpsw #0x40 -> nop; \n\t"
57 DCACHE_CLEAR("%0", "r6", "%3")
58 "lock %0, @%3; \n\t"
59 "unlock %1, @%3; \n\t"
60 "mvtc %2, psw; \n\t"
61 : "=&r" (oldval), "=&r" (tmp1), "=&r" (tmp2)
62 : "r" (&lock->slock)
63 : "memory"
64 #ifdef CONFIG_CHIP_M32700_TS1
65 , "r6"
66 #endif /* CONFIG_CHIP_M32700_TS1 */
67 );
68
69 return (oldval > 0);
70 }
71
arch_spin_lock(arch_spinlock_t * lock)72 static inline void arch_spin_lock(arch_spinlock_t *lock)
73 {
74 unsigned long tmp0, tmp1;
75
76 /*
77 * lock->slock : =1 : unlock
78 * : <=0 : lock
79 *
80 * for ( ; ; ) {
81 * lock->slock -= 1; <-- need atomic operation
82 * if (lock->slock == 0) break;
83 * for ( ; lock->slock <= 0 ; );
84 * }
85 */
86 __asm__ __volatile__ (
87 "# arch_spin_lock \n\t"
88 ".fillinsn \n"
89 "1: \n\t"
90 "mvfc %1, psw; \n\t"
91 "clrpsw #0x40 -> nop; \n\t"
92 DCACHE_CLEAR("%0", "r6", "%2")
93 "lock %0, @%2; \n\t"
94 "addi %0, #-1; \n\t"
95 "unlock %0, @%2; \n\t"
96 "mvtc %1, psw; \n\t"
97 "bltz %0, 2f; \n\t"
98 LOCK_SECTION_START(".balign 4 \n\t")
99 ".fillinsn \n"
100 "2: \n\t"
101 "ld %0, @%2; \n\t"
102 "bgtz %0, 1b; \n\t"
103 "bra 2b; \n\t"
104 LOCK_SECTION_END
105 : "=&r" (tmp0), "=&r" (tmp1)
106 : "r" (&lock->slock)
107 : "memory"
108 #ifdef CONFIG_CHIP_M32700_TS1
109 , "r6"
110 #endif /* CONFIG_CHIP_M32700_TS1 */
111 );
112 }
113
arch_spin_unlock(arch_spinlock_t * lock)114 static inline void arch_spin_unlock(arch_spinlock_t *lock)
115 {
116 mb();
117 lock->slock = 1;
118 }
119
120 /*
121 * Read-write spinlocks, allowing multiple readers
122 * but only one writer.
123 *
124 * NOTE! it is quite common to have readers in interrupts
125 * but no interrupt writers. For those circumstances we
126 * can "mix" irq-safe locks - any writer needs to get a
127 * irq-safe write-lock, but readers can get non-irqsafe
128 * read-locks.
129 *
130 * On x86, we implement read-write locks as a 32-bit counter
131 * with the high bit (sign) being the "contended" bit.
132 *
133 * The inline assembly is non-obvious. Think about it.
134 *
135 * Changed to use the same technique as rw semaphores. See
136 * semaphore.h for details. -ben
137 */
138
139 /**
140 * read_can_lock - would read_trylock() succeed?
141 * @lock: the rwlock in question.
142 */
143 #define arch_read_can_lock(x) ((int)(x)->lock > 0)
144
145 /**
146 * write_can_lock - would write_trylock() succeed?
147 * @lock: the rwlock in question.
148 */
149 #define arch_write_can_lock(x) ((x)->lock == RW_LOCK_BIAS)
150
arch_read_lock(arch_rwlock_t * rw)151 static inline void arch_read_lock(arch_rwlock_t *rw)
152 {
153 unsigned long tmp0, tmp1;
154
155 /*
156 * rw->lock : >0 : unlock
157 * : <=0 : lock
158 *
159 * for ( ; ; ) {
160 * rw->lock -= 1; <-- need atomic operation
161 * if (rw->lock >= 0) break;
162 * rw->lock += 1; <-- need atomic operation
163 * for ( ; rw->lock <= 0 ; );
164 * }
165 */
166 __asm__ __volatile__ (
167 "# read_lock \n\t"
168 ".fillinsn \n"
169 "1: \n\t"
170 "mvfc %1, psw; \n\t"
171 "clrpsw #0x40 -> nop; \n\t"
172 DCACHE_CLEAR("%0", "r6", "%2")
173 "lock %0, @%2; \n\t"
174 "addi %0, #-1; \n\t"
175 "unlock %0, @%2; \n\t"
176 "mvtc %1, psw; \n\t"
177 "bltz %0, 2f; \n\t"
178 LOCK_SECTION_START(".balign 4 \n\t")
179 ".fillinsn \n"
180 "2: \n\t"
181 "clrpsw #0x40 -> nop; \n\t"
182 DCACHE_CLEAR("%0", "r6", "%2")
183 "lock %0, @%2; \n\t"
184 "addi %0, #1; \n\t"
185 "unlock %0, @%2; \n\t"
186 "mvtc %1, psw; \n\t"
187 ".fillinsn \n"
188 "3: \n\t"
189 "ld %0, @%2; \n\t"
190 "bgtz %0, 1b; \n\t"
191 "bra 3b; \n\t"
192 LOCK_SECTION_END
193 : "=&r" (tmp0), "=&r" (tmp1)
194 : "r" (&rw->lock)
195 : "memory"
196 #ifdef CONFIG_CHIP_M32700_TS1
197 , "r6"
198 #endif /* CONFIG_CHIP_M32700_TS1 */
199 );
200 }
201
arch_write_lock(arch_rwlock_t * rw)202 static inline void arch_write_lock(arch_rwlock_t *rw)
203 {
204 unsigned long tmp0, tmp1, tmp2;
205
206 /*
207 * rw->lock : =RW_LOCK_BIAS_STR : unlock
208 * : !=RW_LOCK_BIAS_STR : lock
209 *
210 * for ( ; ; ) {
211 * rw->lock -= RW_LOCK_BIAS_STR; <-- need atomic operation
212 * if (rw->lock == 0) break;
213 * rw->lock += RW_LOCK_BIAS_STR; <-- need atomic operation
214 * for ( ; rw->lock != RW_LOCK_BIAS_STR ; ) ;
215 * }
216 */
217 __asm__ __volatile__ (
218 "# write_lock \n\t"
219 "seth %1, #high(" RW_LOCK_BIAS_STR "); \n\t"
220 "or3 %1, %1, #low(" RW_LOCK_BIAS_STR "); \n\t"
221 ".fillinsn \n"
222 "1: \n\t"
223 "mvfc %2, psw; \n\t"
224 "clrpsw #0x40 -> nop; \n\t"
225 DCACHE_CLEAR("%0", "r7", "%3")
226 "lock %0, @%3; \n\t"
227 "sub %0, %1; \n\t"
228 "unlock %0, @%3; \n\t"
229 "mvtc %2, psw; \n\t"
230 "bnez %0, 2f; \n\t"
231 LOCK_SECTION_START(".balign 4 \n\t")
232 ".fillinsn \n"
233 "2: \n\t"
234 "clrpsw #0x40 -> nop; \n\t"
235 DCACHE_CLEAR("%0", "r7", "%3")
236 "lock %0, @%3; \n\t"
237 "add %0, %1; \n\t"
238 "unlock %0, @%3; \n\t"
239 "mvtc %2, psw; \n\t"
240 ".fillinsn \n"
241 "3: \n\t"
242 "ld %0, @%3; \n\t"
243 "beq %0, %1, 1b; \n\t"
244 "bra 3b; \n\t"
245 LOCK_SECTION_END
246 : "=&r" (tmp0), "=&r" (tmp1), "=&r" (tmp2)
247 : "r" (&rw->lock)
248 : "memory"
249 #ifdef CONFIG_CHIP_M32700_TS1
250 , "r7"
251 #endif /* CONFIG_CHIP_M32700_TS1 */
252 );
253 }
254
arch_read_unlock(arch_rwlock_t * rw)255 static inline void arch_read_unlock(arch_rwlock_t *rw)
256 {
257 unsigned long tmp0, tmp1;
258
259 __asm__ __volatile__ (
260 "# read_unlock \n\t"
261 "mvfc %1, psw; \n\t"
262 "clrpsw #0x40 -> nop; \n\t"
263 DCACHE_CLEAR("%0", "r6", "%2")
264 "lock %0, @%2; \n\t"
265 "addi %0, #1; \n\t"
266 "unlock %0, @%2; \n\t"
267 "mvtc %1, psw; \n\t"
268 : "=&r" (tmp0), "=&r" (tmp1)
269 : "r" (&rw->lock)
270 : "memory"
271 #ifdef CONFIG_CHIP_M32700_TS1
272 , "r6"
273 #endif /* CONFIG_CHIP_M32700_TS1 */
274 );
275 }
276
arch_write_unlock(arch_rwlock_t * rw)277 static inline void arch_write_unlock(arch_rwlock_t *rw)
278 {
279 unsigned long tmp0, tmp1, tmp2;
280
281 __asm__ __volatile__ (
282 "# write_unlock \n\t"
283 "seth %1, #high(" RW_LOCK_BIAS_STR "); \n\t"
284 "or3 %1, %1, #low(" RW_LOCK_BIAS_STR "); \n\t"
285 "mvfc %2, psw; \n\t"
286 "clrpsw #0x40 -> nop; \n\t"
287 DCACHE_CLEAR("%0", "r7", "%3")
288 "lock %0, @%3; \n\t"
289 "add %0, %1; \n\t"
290 "unlock %0, @%3; \n\t"
291 "mvtc %2, psw; \n\t"
292 : "=&r" (tmp0), "=&r" (tmp1), "=&r" (tmp2)
293 : "r" (&rw->lock)
294 : "memory"
295 #ifdef CONFIG_CHIP_M32700_TS1
296 , "r7"
297 #endif /* CONFIG_CHIP_M32700_TS1 */
298 );
299 }
300
arch_read_trylock(arch_rwlock_t * lock)301 static inline int arch_read_trylock(arch_rwlock_t *lock)
302 {
303 atomic_t *count = (atomic_t*)lock;
304 if (atomic_dec_return(count) >= 0)
305 return 1;
306 atomic_inc(count);
307 return 0;
308 }
309
arch_write_trylock(arch_rwlock_t * lock)310 static inline int arch_write_trylock(arch_rwlock_t *lock)
311 {
312 atomic_t *count = (atomic_t *)lock;
313 if (atomic_sub_and_test(RW_LOCK_BIAS, count))
314 return 1;
315 atomic_add(RW_LOCK_BIAS, count);
316 return 0;
317 }
318
319 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
320 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
321
322 #define arch_spin_relax(lock) cpu_relax()
323 #define arch_read_relax(lock) cpu_relax()
324 #define arch_write_relax(lock) cpu_relax()
325
326 #endif /* _ASM_M32R_SPINLOCK_H */
327