summaryrefslogtreecommitdiff
path: root/include/asm-m32r/spinlock.h
blob: 6608d8371c5084541c2d84cb95e0f1df12eeb8f8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
#ifndef _ASM_M32R_SPINLOCK_H
#define _ASM_M32R_SPINLOCK_H

/*
 *  linux/include/asm-m32r/spinlock.h
 *
 *  M32R version:
 *    Copyright (C) 2001, 2002  Hitoshi Yamamoto
 *    Copyright (C) 2004  Hirokazu Takata <takata at linux-m32r.org>
 */

#include <linux/config.h>	/* CONFIG_DEBUG_SPINLOCK, CONFIG_SMP */
#include <linux/compiler.h>
#include <asm/atomic.h>
#include <asm/page.h>

extern int printk(const char * fmt, ...)
	__attribute__ ((format (printf, 1, 2)));

#define RW_LOCK_BIAS		 0x01000000
#define RW_LOCK_BIAS_STR	"0x01000000"

/*
 * Your basic SMP spinlocks, allowing only a single CPU anywhere
 */

typedef struct {
	volatile int slock;
#ifdef CONFIG_DEBUG_SPINLOCK
	unsigned magic;
#endif
#ifdef CONFIG_PREEMPT
	unsigned int break_lock;
#endif
} spinlock_t;

#define SPINLOCK_MAGIC	0xdead4ead

#ifdef CONFIG_DEBUG_SPINLOCK
#define SPINLOCK_MAGIC_INIT	, SPINLOCK_MAGIC
#else
#define SPINLOCK_MAGIC_INIT	/* */
#endif

#define SPIN_LOCK_UNLOCKED (spinlock_t) { 1 SPINLOCK_MAGIC_INIT }

#define spin_lock_init(x)	do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)

/*
 * Simple spin lock operations.  There are two variants, one clears IRQ's
 * on the local processor, one does not.
 *
 * We make no fairness assumptions. They have a cost.
 */

#define spin_is_locked(x)	(*(volatile int *)(&(x)->slock) <= 0)
#define spin_unlock_wait(x)	do { barrier(); } while(spin_is_locked(x))
#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)

/**
 * _raw_spin_trylock - Try spin lock and return a result
 * @lock: Pointer to the lock variable
 *
 * _raw_spin_trylock() tries to get the lock and returns a result.
 * On the m32r, the result value is 1 (= Success) or 0 (= Failure).
 */
static inline int _raw_spin_trylock(spinlock_t *lock)
{
	int oldval;
	unsigned long tmp1, tmp2;

	/*
	 * lock->slock :  =1 : unlock
	 *             : <=0 : lock
	 * {
	 *   oldval = lock->slock; <--+ need atomic operation
	 *   lock->slock = 0;      <--+
	 * }
	 */
	__asm__ __volatile__ (
		"# spin_trylock			\n\t"
		"ldi	%1, #0;			\n\t"
		"mvfc	%2, psw;		\n\t"
		"clrpsw	#0x40 -> nop;		\n\t"
		DCACHE_CLEAR("%0", "r6", "%3")
		"lock	%0, @%3;		\n\t"
		"unlock	%1, @%3;		\n\t"
		"mvtc	%2, psw;		\n\t"
		: "=&r" (oldval), "=&r" (tmp1), "=&r" (tmp2)
		: "r" (&lock->slock)
		: "memory"
#ifdef CONFIG_CHIP_M32700_TS1
		, "r6"
#endif	/* CONFIG_CHIP_M32700_TS1 */
	);

	return (oldval > 0);
}

static inline void _raw_spin_lock(spinlock_t *lock)
{
	unsigned long tmp0, tmp1;

#ifdef CONFIG_DEBUG_SPINLOCK
	if (unlikely(lock->magic != SPINLOCK_MAGIC)) {
		printk("pc: %p\n", __builtin_return_address(0));
		BUG();
	}
#endif
	/*
	 * lock->slock :  =1 : unlock
	 *             : <=0 : lock
	 *
	 * for ( ; ; ) {
	 *   lock->slock -= 1;  <-- need atomic operation
	 *   if (lock->slock == 0) break;
	 *   for ( ; lock->slock <= 0 ; );
	 * }
	 */
	__asm__ __volatile__ (
		"# spin_lock			\n\t"
		".fillinsn			\n"
		"1:				\n\t"
		"mvfc	%1, psw;		\n\t"
		"clrpsw	#0x40 -> nop;		\n\t"
		DCACHE_CLEAR("%0", "r6", "%2")
		"lock	%0, @%2;		\n\t"
		"addi	%0, #-1;		\n\t"
		"unlock	%0, @%2;		\n\t"
		"mvtc	%1, psw;		\n\t"
		"bltz	%0, 2f;			\n\t"
		LOCK_SECTION_START(".balign 4 \n\t")
		".fillinsn			\n"
		"2:				\n\t"
		"ld	%0, @%2;		\n\t"
		"bgtz	%0, 1b;			\n\t"
		"bra	2b;			\n\t"
		LOCK_SECTION_END
		: "=&r" (tmp0), "=&r" (tmp1)
		: "r" (&lock->slock)
		: "memory"
#ifdef CONFIG_CHIP_M32700_TS1
		, "r6"
#endif	/* CONFIG_CHIP_M32700_TS1 */
	);
}

static inline void _raw_spin_unlock(spinlock_t *lock)
{
#ifdef CONFIG_DEBUG_SPINLOCK
	BUG_ON(lock->magic != SPINLOCK_MAGIC);
	BUG_ON(!spin_is_locked(lock));
#endif
	mb();
	lock->slock = 1;
}

/*
 * Read-write spinlocks, allowing multiple readers
 * but only one writer.
 *
 * NOTE! it is quite common to have readers in interrupts
 * but no interrupt writers. For those circumstances we
 * can "mix" irq-safe locks - any writer needs to get a
 * irq-safe write-lock, but readers can get non-irqsafe
 * read-locks.
 */
typedef struct {
	volatile int lock;
#ifdef CONFIG_DEBUG_SPINLOCK
	unsigned magic;
#endif
#ifdef CONFIG_PREEMPT
	unsigned int break_lock;
#endif
} rwlock_t;

#define RWLOCK_MAGIC	0xdeaf1eed

#ifdef CONFIG_DEBUG_SPINLOCK
#define RWLOCK_MAGIC_INIT	, RWLOCK_MAGIC
#else
#define RWLOCK_MAGIC_INIT	/* */
#endif

#define RW_LOCK_UNLOCKED (rwlock_t) { RW_LOCK_BIAS RWLOCK_MAGIC_INIT }

#define rwlock_init(x)	do { *(x) = RW_LOCK_UNLOCKED; } while(0)

/**
 * read_can_lock - would read_trylock() succeed?
 * @lock: the rwlock in question.
 */
#define read_can_lock(x) ((int)(x)->lock > 0)

/**
 * write_can_lock - would write_trylock() succeed?
 * @lock: the rwlock in question.
 */
#define write_can_lock(x) ((x)->lock == RW_LOCK_BIAS)

/*
 * On x86, we implement read-write locks as a 32-bit counter
 * with the high bit (sign) being the "contended" bit.
 *
 * The inline assembly is non-obvious. Think about it.
 *
 * Changed to use the same technique as rw semaphores.  See
 * semaphore.h for details.  -ben
 */
/* the spinlock helpers are in arch/i386/kernel/semaphore.c */

static inline void _raw_read_lock(rwlock_t *rw)
{
	unsigned long tmp0, tmp1;

#ifdef CONFIG_DEBUG_SPINLOCK
	BUG_ON(rw->magic != RWLOCK_MAGIC);
#endif
	/*
	 * rw->lock :  >0 : unlock
	 *          : <=0 : lock
	 *
	 * for ( ; ; ) {
	 *   rw->lock -= 1;  <-- need atomic operation
	 *   if (rw->lock >= 0) break;
	 *   rw->lock += 1;  <-- need atomic operation
	 *   for ( ; rw->lock <= 0 ; );
	 * }
	 */
	__asm__ __volatile__ (
		"# read_lock			\n\t"
		".fillinsn			\n"
		"1:				\n\t"
		"mvfc	%1, psw;		\n\t"
		"clrpsw	#0x40 -> nop;		\n\t"
		DCACHE_CLEAR("%0", "r6", "%2")
		"lock	%0, @%2;		\n\t"
		"addi	%0, #-1;		\n\t"
		"unlock	%0, @%2;		\n\t"
		"mvtc	%1, psw;		\n\t"
		"bltz	%0, 2f;			\n\t"
		LOCK_SECTION_START(".balign 4 \n\t")
		".fillinsn			\n"
		"2:				\n\t"
		"clrpsw	#0x40 -> nop;		\n\t"
		DCACHE_CLEAR("%0", "r6", "%2")
		"lock	%0, @%2;		\n\t"
		"addi	%0, #1;			\n\t"
		"unlock	%0, @%2;		\n\t"
		"mvtc	%1, psw;		\n\t"
		".fillinsn			\n"
		"3:				\n\t"
		"ld	%0, @%2;		\n\t"
		"bgtz	%0, 1b;			\n\t"
		"bra	3b;			\n\t"
		LOCK_SECTION_END
		: "=&r" (tmp0), "=&r" (tmp1)
		: "r" (&rw->lock)
		: "memory"
#ifdef CONFIG_CHIP_M32700_TS1
		, "r6"
#endif	/* CONFIG_CHIP_M32700_TS1 */
	);
}

static inline void _raw_write_lock(rwlock_t *rw)
{
	unsigned long tmp0, tmp1, tmp2;

#ifdef CONFIG_DEBUG_SPINLOCK
	BUG_ON(rw->magic != RWLOCK_MAGIC);
#endif
	/*
	 * rw->lock :  =RW_LOCK_BIAS_STR : unlock
	 *          : !=RW_LOCK_BIAS_STR : lock
	 *
	 * for ( ; ; ) {
	 *   rw->lock -= RW_LOCK_BIAS_STR;  <-- need atomic operation
	 *   if (rw->lock == 0) break;
	 *   rw->lock += RW_LOCK_BIAS_STR;  <-- need atomic operation
	 *   for ( ; rw->lock != RW_LOCK_BIAS_STR ; ) ;
	 * }
	 */
	__asm__ __volatile__ (
		"# write_lock					\n\t"
		"seth	%1, #high(" RW_LOCK_BIAS_STR ");	\n\t"
		"or3	%1, %1, #low(" RW_LOCK_BIAS_STR ");	\n\t"
		".fillinsn					\n"
		"1:						\n\t"
		"mvfc	%2, psw;				\n\t"
		"clrpsw	#0x40 -> nop;				\n\t"
		DCACHE_CLEAR("%0", "r7", "%3")
		"lock	%0, @%3;				\n\t"
		"sub	%0, %1;					\n\t"
		"unlock	%0, @%3;				\n\t"
		"mvtc	%2, psw;				\n\t"
		"bnez	%0, 2f;					\n\t"
		LOCK_SECTION_START(".balign 4 \n\t")
		".fillinsn					\n"
		"2:						\n\t"
		"clrpsw	#0x40 -> nop;				\n\t"
		DCACHE_CLEAR("%0", "r7", "%3")
		"lock	%0, @%3;				\n\t"
		"add	%0, %1;					\n\t"
		"unlock	%0, @%3;				\n\t"
		"mvtc	%2, psw;				\n\t"
		".fillinsn					\n"
		"3:						\n\t"
		"ld	%0, @%3;				\n\t"
		"beq	%0, %1, 1b;				\n\t"
		"bra	3b;					\n\t"
		LOCK_SECTION_END
		: "=&r" (tmp0), "=&r" (tmp1), "=&r" (tmp2)
		: "r" (&rw->lock)
		: "memory"
#ifdef CONFIG_CHIP_M32700_TS1
		, "r7"
#endif	/* CONFIG_CHIP_M32700_TS1 */
	);
}

static inline void _raw_read_unlock(rwlock_t *rw)
{
	unsigned long tmp0, tmp1;

	__asm__ __volatile__ (
		"# read_unlock			\n\t"
		"mvfc	%1, psw;		\n\t"
		"clrpsw	#0x40 -> nop;		\n\t"
		DCACHE_CLEAR("%0", "r6", "%2")
		"lock	%0, @%2;		\n\t"
		"addi	%0, #1;			\n\t"
		"unlock	%0, @%2;		\n\t"
		"mvtc	%1, psw;		\n\t"
		: "=&r" (tmp0), "=&r" (tmp1)
		: "r" (&rw->lock)
		: "memory"
#ifdef CONFIG_CHIP_M32700_TS1
		, "r6"
#endif	/* CONFIG_CHIP_M32700_TS1 */
	);
}

static inline void _raw_write_unlock(rwlock_t *rw)
{
	unsigned long tmp0, tmp1, tmp2;

	__asm__ __volatile__ (
		"# write_unlock					\n\t"
		"seth	%1, #high(" RW_LOCK_BIAS_STR ");	\n\t"
		"or3	%1, %1, #low(" RW_LOCK_BIAS_STR ");	\n\t"
		"mvfc	%2, psw;				\n\t"
		"clrpsw	#0x40 -> nop;				\n\t"
		DCACHE_CLEAR("%0", "r7", "%3")
		"lock	%0, @%3;				\n\t"
		"add	%0, %1;					\n\t"
		"unlock	%0, @%3;				\n\t"
		"mvtc	%2, psw;				\n\t"
		: "=&r" (tmp0), "=&r" (tmp1), "=&r" (tmp2)
		: "r" (&rw->lock)
		: "memory"
#ifdef CONFIG_CHIP_M32700_TS1
		, "r7"
#endif	/* CONFIG_CHIP_M32700_TS1 */
	);
}

#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)

static inline int _raw_write_trylock(rwlock_t *lock)
{
	atomic_t *count = (atomic_t *)lock;
	if (atomic_sub_and_test(RW_LOCK_BIAS, count))
		return 1;
	atomic_add(RW_LOCK_BIAS, count);
	return 0;
}

#endif	/* _ASM_M32R_SPINLOCK_H */