Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6-block.git] / arch / arm / include / asm / bitops.h
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1/*
2 * Copyright 1995, Russell King.
3 * Various bits and pieces copyrights include:
4 * Linus Torvalds (test_bit).
5 * Big endian support: Copyright 2001, Nicolas Pitre
6 * reworked by rmk.
7 *
8 * bit 0 is the LSB of an "unsigned long" quantity.
9 *
10 * Please note that the code in this file should never be included
11 * from user space. Many of these are not implemented in assembler
12 * since they would be too costly. Also, they require privileged
13 * instructions (which are not available from user mode) to ensure
14 * that they are atomic.
15 */
16
17#ifndef __ASM_ARM_BITOPS_H
18#define __ASM_ARM_BITOPS_H
19
20#ifdef __KERNEL__
21
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22#ifndef _LINUX_BITOPS_H
23#error only <linux/bitops.h> can be included directly
24#endif
25
8dc39b88 26#include <linux/compiler.h>
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27#include <asm/system.h>
28
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29#define smp_mb__before_clear_bit() mb()
30#define smp_mb__after_clear_bit() mb()
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31
32/*
33 * These functions are the basis of our bit ops.
34 *
35 * First, the atomic bitops. These use native endian.
36 */
37static inline void ____atomic_set_bit(unsigned int bit, volatile unsigned long *p)
38{
39 unsigned long flags;
40 unsigned long mask = 1UL << (bit & 31);
41
42 p += bit >> 5;
43
e7cc2c59 44 raw_local_irq_save(flags);
1da177e4 45 *p |= mask;
e7cc2c59 46 raw_local_irq_restore(flags);
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47}
48
49static inline void ____atomic_clear_bit(unsigned int bit, volatile unsigned long *p)
50{
51 unsigned long flags;
52 unsigned long mask = 1UL << (bit & 31);
53
54 p += bit >> 5;
55
e7cc2c59 56 raw_local_irq_save(flags);
1da177e4 57 *p &= ~mask;
e7cc2c59 58 raw_local_irq_restore(flags);
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59}
60
61static inline void ____atomic_change_bit(unsigned int bit, volatile unsigned long *p)
62{
63 unsigned long flags;
64 unsigned long mask = 1UL << (bit & 31);
65
66 p += bit >> 5;
67
e7cc2c59 68 raw_local_irq_save(flags);
1da177e4 69 *p ^= mask;
e7cc2c59 70 raw_local_irq_restore(flags);
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71}
72
73static inline int
74____atomic_test_and_set_bit(unsigned int bit, volatile unsigned long *p)
75{
76 unsigned long flags;
77 unsigned int res;
78 unsigned long mask = 1UL << (bit & 31);
79
80 p += bit >> 5;
81
e7cc2c59 82 raw_local_irq_save(flags);
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83 res = *p;
84 *p = res | mask;
e7cc2c59 85 raw_local_irq_restore(flags);
1da177e4 86
e9ac8291 87 return (res & mask) != 0;
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88}
89
90static inline int
91____atomic_test_and_clear_bit(unsigned int bit, volatile unsigned long *p)
92{
93 unsigned long flags;
94 unsigned int res;
95 unsigned long mask = 1UL << (bit & 31);
96
97 p += bit >> 5;
98
e7cc2c59 99 raw_local_irq_save(flags);
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100 res = *p;
101 *p = res & ~mask;
e7cc2c59 102 raw_local_irq_restore(flags);
1da177e4 103
e9ac8291 104 return (res & mask) != 0;
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105}
106
107static inline int
108____atomic_test_and_change_bit(unsigned int bit, volatile unsigned long *p)
109{
110 unsigned long flags;
111 unsigned int res;
112 unsigned long mask = 1UL << (bit & 31);
113
114 p += bit >> 5;
115
e7cc2c59 116 raw_local_irq_save(flags);
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117 res = *p;
118 *p = res ^ mask;
e7cc2c59 119 raw_local_irq_restore(flags);
1da177e4 120
e9ac8291 121 return (res & mask) != 0;
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122}
123
b89c3b16 124#include <asm-generic/bitops/non-atomic.h>
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125
126/*
127 * A note about Endian-ness.
128 * -------------------------
129 *
130 * When the ARM is put into big endian mode via CR15, the processor
131 * merely swaps the order of bytes within words, thus:
132 *
133 * ------------ physical data bus bits -----------
134 * D31 ... D24 D23 ... D16 D15 ... D8 D7 ... D0
135 * little byte 3 byte 2 byte 1 byte 0
136 * big byte 0 byte 1 byte 2 byte 3
137 *
138 * This means that reading a 32-bit word at address 0 returns the same
139 * value irrespective of the endian mode bit.
140 *
141 * Peripheral devices should be connected with the data bus reversed in
142 * "Big Endian" mode. ARM Application Note 61 is applicable, and is
143 * available from http://www.arm.com/.
144 *
145 * The following assumes that the data bus connectivity for big endian
146 * mode has been followed.
147 *
148 * Note that bit 0 is defined to be 32-bit word bit 0, not byte 0 bit 0.
149 */
150
151/*
152 * Little endian assembly bitops. nr = 0 -> byte 0 bit 0.
153 */
154extern void _set_bit_le(int nr, volatile unsigned long * p);
155extern void _clear_bit_le(int nr, volatile unsigned long * p);
156extern void _change_bit_le(int nr, volatile unsigned long * p);
157extern int _test_and_set_bit_le(int nr, volatile unsigned long * p);
158extern int _test_and_clear_bit_le(int nr, volatile unsigned long * p);
159extern int _test_and_change_bit_le(int nr, volatile unsigned long * p);
160extern int _find_first_zero_bit_le(const void * p, unsigned size);
161extern int _find_next_zero_bit_le(const void * p, int size, int offset);
162extern int _find_first_bit_le(const unsigned long *p, unsigned size);
163extern int _find_next_bit_le(const unsigned long *p, int size, int offset);
164
165/*
166 * Big endian assembly bitops. nr = 0 -> byte 3 bit 0.
167 */
168extern void _set_bit_be(int nr, volatile unsigned long * p);
169extern void _clear_bit_be(int nr, volatile unsigned long * p);
170extern void _change_bit_be(int nr, volatile unsigned long * p);
171extern int _test_and_set_bit_be(int nr, volatile unsigned long * p);
172extern int _test_and_clear_bit_be(int nr, volatile unsigned long * p);
173extern int _test_and_change_bit_be(int nr, volatile unsigned long * p);
174extern int _find_first_zero_bit_be(const void * p, unsigned size);
175extern int _find_next_zero_bit_be(const void * p, int size, int offset);
176extern int _find_first_bit_be(const unsigned long *p, unsigned size);
177extern int _find_next_bit_be(const unsigned long *p, int size, int offset);
178
e7ec0293 179#ifndef CONFIG_SMP
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180/*
181 * The __* form of bitops are non-atomic and may be reordered.
182 */
183#define ATOMIC_BITOP_LE(name,nr,p) \
184 (__builtin_constant_p(nr) ? \
185 ____atomic_##name(nr, p) : \
186 _##name##_le(nr,p))
187
188#define ATOMIC_BITOP_BE(name,nr,p) \
189 (__builtin_constant_p(nr) ? \
190 ____atomic_##name(nr, p) : \
191 _##name##_be(nr,p))
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192#else
193#define ATOMIC_BITOP_LE(name,nr,p) _##name##_le(nr,p)
194#define ATOMIC_BITOP_BE(name,nr,p) _##name##_be(nr,p)
195#endif
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196
197#define NONATOMIC_BITOP(name,nr,p) \
198 (____nonatomic_##name(nr, p))
199
200#ifndef __ARMEB__
201/*
202 * These are the little endian, atomic definitions.
203 */
204#define set_bit(nr,p) ATOMIC_BITOP_LE(set_bit,nr,p)
205#define clear_bit(nr,p) ATOMIC_BITOP_LE(clear_bit,nr,p)
206#define change_bit(nr,p) ATOMIC_BITOP_LE(change_bit,nr,p)
207#define test_and_set_bit(nr,p) ATOMIC_BITOP_LE(test_and_set_bit,nr,p)
208#define test_and_clear_bit(nr,p) ATOMIC_BITOP_LE(test_and_clear_bit,nr,p)
209#define test_and_change_bit(nr,p) ATOMIC_BITOP_LE(test_and_change_bit,nr,p)
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210#define find_first_zero_bit(p,sz) _find_first_zero_bit_le(p,sz)
211#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_le(p,sz,off)
212#define find_first_bit(p,sz) _find_first_bit_le(p,sz)
213#define find_next_bit(p,sz,off) _find_next_bit_le(p,sz,off)
214
215#define WORD_BITOFF_TO_LE(x) ((x))
216
217#else
218
219/*
220 * These are the big endian, atomic definitions.
221 */
222#define set_bit(nr,p) ATOMIC_BITOP_BE(set_bit,nr,p)
223#define clear_bit(nr,p) ATOMIC_BITOP_BE(clear_bit,nr,p)
224#define change_bit(nr,p) ATOMIC_BITOP_BE(change_bit,nr,p)
225#define test_and_set_bit(nr,p) ATOMIC_BITOP_BE(test_and_set_bit,nr,p)
226#define test_and_clear_bit(nr,p) ATOMIC_BITOP_BE(test_and_clear_bit,nr,p)
227#define test_and_change_bit(nr,p) ATOMIC_BITOP_BE(test_and_change_bit,nr,p)
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228#define find_first_zero_bit(p,sz) _find_first_zero_bit_be(p,sz)
229#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_be(p,sz,off)
230#define find_first_bit(p,sz) _find_first_bit_be(p,sz)
231#define find_next_bit(p,sz,off) _find_next_bit_be(p,sz,off)
232
233#define WORD_BITOFF_TO_LE(x) ((x) ^ 0x18)
234
235#endif
236
237#if __LINUX_ARM_ARCH__ < 5
238
b89c3b16 239#include <asm-generic/bitops/ffz.h>
94fc7336 240#include <asm-generic/bitops/__fls.h>
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241#include <asm-generic/bitops/__ffs.h>
242#include <asm-generic/bitops/fls.h>
243#include <asm-generic/bitops/ffs.h>
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244
245#else
246
93635133
AM
247static inline int constant_fls(int x)
248{
249 int r = 32;
250
251 if (!x)
252 return 0;
253 if (!(x & 0xffff0000u)) {
254 x <<= 16;
255 r -= 16;
256 }
257 if (!(x & 0xff000000u)) {
258 x <<= 8;
259 r -= 8;
260 }
261 if (!(x & 0xf0000000u)) {
262 x <<= 4;
263 r -= 4;
264 }
265 if (!(x & 0xc0000000u)) {
266 x <<= 2;
267 r -= 2;
268 }
269 if (!(x & 0x80000000u)) {
270 x <<= 1;
271 r -= 1;
272 }
273 return r;
274}
275
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276/*
277 * On ARMv5 and above those functions can be implemented around
278 * the clz instruction for much better code efficiency.
279 */
280
0c65f459
AM
281static inline int fls(int x)
282{
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283 int ret;
284
285 if (__builtin_constant_p(x))
286 return constant_fls(x);
287
288 asm("clz\t%0, %1" : "=r" (ret) : "r" (x) : "cc");
289 ret = 32 - ret;
290 return ret;
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291}
292
94fc7336 293#define __fls(x) (fls(x) - 1)
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294#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })
295#define __ffs(x) (ffs(x) - 1)
296#define ffz(x) __ffs( ~(x) )
297
298#endif
299
b89c3b16 300#include <asm-generic/bitops/fls64.h>
1da177e4 301
b89c3b16
AM
302#include <asm-generic/bitops/sched.h>
303#include <asm-generic/bitops/hweight.h>
26333576 304#include <asm-generic/bitops/lock.h>
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305
306/*
307 * Ext2 is defined to use little-endian byte ordering.
308 * These do not need to be atomic.
309 */
310#define ext2_set_bit(nr,p) \
311 __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
312#define ext2_set_bit_atomic(lock,nr,p) \
313 test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
314#define ext2_clear_bit(nr,p) \
315 __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
316#define ext2_clear_bit_atomic(lock,nr,p) \
317 test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
318#define ext2_test_bit(nr,p) \
b89c3b16 319 test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
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320#define ext2_find_first_zero_bit(p,sz) \
321 _find_first_zero_bit_le(p,sz)
322#define ext2_find_next_zero_bit(p,sz,off) \
323 _find_next_zero_bit_le(p,sz,off)
aa02ad67
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324#define ext2_find_next_bit(p, sz, off) \
325 _find_next_bit_le(p, sz, off)
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326
327/*
328 * Minix is defined to use little-endian byte ordering.
329 * These do not need to be atomic.
330 */
331#define minix_set_bit(nr,p) \
332 __set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
333#define minix_test_bit(nr,p) \
b89c3b16 334 test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
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335#define minix_test_and_set_bit(nr,p) \
336 __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
337#define minix_test_and_clear_bit(nr,p) \
338 __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
339#define minix_find_first_zero_bit(p,sz) \
340 _find_first_zero_bit_le(p,sz)
341
342#endif /* __KERNEL__ */
343
344#endif /* _ARM_BITOPS_H */