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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
22#include <asm/system.h>
23
24#define smp_mb__before_clear_bit() mb()
25#define smp_mb__after_clear_bit() mb()
26
27/*
28 * These functions are the basis of our bit ops.
29 *
30 * First, the atomic bitops. These use native endian.
31 */
32static inline void ____atomic_set_bit(unsigned int bit, volatile unsigned long *p)
33{
34 unsigned long flags;
35 unsigned long mask = 1UL << (bit & 31);
36
37 p += bit >> 5;
38
39 local_irq_save(flags);
40 *p |= mask;
41 local_irq_restore(flags);
42}
43
44static inline void ____atomic_clear_bit(unsigned int bit, volatile unsigned long *p)
45{
46 unsigned long flags;
47 unsigned long mask = 1UL << (bit & 31);
48
49 p += bit >> 5;
50
51 local_irq_save(flags);
52 *p &= ~mask;
53 local_irq_restore(flags);
54}
55
56static inline void ____atomic_change_bit(unsigned int bit, volatile unsigned long *p)
57{
58 unsigned long flags;
59 unsigned long mask = 1UL << (bit & 31);
60
61 p += bit >> 5;
62
63 local_irq_save(flags);
64 *p ^= mask;
65 local_irq_restore(flags);
66}
67
68static inline int
69____atomic_test_and_set_bit(unsigned int bit, volatile unsigned long *p)
70{
71 unsigned long flags;
72 unsigned int res;
73 unsigned long mask = 1UL << (bit & 31);
74
75 p += bit >> 5;
76
77 local_irq_save(flags);
78 res = *p;
79 *p = res | mask;
80 local_irq_restore(flags);
81
82 return res & mask;
83}
84
85static inline int
86____atomic_test_and_clear_bit(unsigned int bit, volatile unsigned long *p)
87{
88 unsigned long flags;
89 unsigned int res;
90 unsigned long mask = 1UL << (bit & 31);
91
92 p += bit >> 5;
93
94 local_irq_save(flags);
95 res = *p;
96 *p = res & ~mask;
97 local_irq_restore(flags);
98
99 return res & mask;
100}
101
102static inline int
103____atomic_test_and_change_bit(unsigned int bit, volatile unsigned long *p)
104{
105 unsigned long flags;
106 unsigned int res;
107 unsigned long mask = 1UL << (bit & 31);
108
109 p += bit >> 5;
110
111 local_irq_save(flags);
112 res = *p;
113 *p = res ^ mask;
114 local_irq_restore(flags);
115
116 return res & mask;
117}
118
119/*
120 * Now the non-atomic variants. We let the compiler handle all
121 * optimisations for these. These are all _native_ endian.
122 */
123static inline void __set_bit(int nr, volatile unsigned long *p)
124{
125 p[nr >> 5] |= (1UL << (nr & 31));
126}
127
128static inline void __clear_bit(int nr, volatile unsigned long *p)
129{
130 p[nr >> 5] &= ~(1UL << (nr & 31));
131}
132
133static inline void __change_bit(int nr, volatile unsigned long *p)
134{
135 p[nr >> 5] ^= (1UL << (nr & 31));
136}
137
138static inline int __test_and_set_bit(int nr, volatile unsigned long *p)
139{
140 unsigned long oldval, mask = 1UL << (nr & 31);
141
142 p += nr >> 5;
143
144 oldval = *p;
145 *p = oldval | mask;
146 return oldval & mask;
147}
148
149static inline int __test_and_clear_bit(int nr, volatile unsigned long *p)
150{
151 unsigned long oldval, mask = 1UL << (nr & 31);
152
153 p += nr >> 5;
154
155 oldval = *p;
156 *p = oldval & ~mask;
157 return oldval & mask;
158}
159
160static inline int __test_and_change_bit(int nr, volatile unsigned long *p)
161{
162 unsigned long oldval, mask = 1UL << (nr & 31);
163
164 p += nr >> 5;
165
166 oldval = *p;
167 *p = oldval ^ mask;
168 return oldval & mask;
169}
170
171/*
172 * This routine doesn't need to be atomic.
173 */
174static inline int __test_bit(int nr, const volatile unsigned long * p)
175{
176 return (p[nr >> 5] >> (nr & 31)) & 1UL;
177}
178
179/*
180 * A note about Endian-ness.
181 * -------------------------
182 *
183 * When the ARM is put into big endian mode via CR15, the processor
184 * merely swaps the order of bytes within words, thus:
185 *
186 * ------------ physical data bus bits -----------
187 * D31 ... D24 D23 ... D16 D15 ... D8 D7 ... D0
188 * little byte 3 byte 2 byte 1 byte 0
189 * big byte 0 byte 1 byte 2 byte 3
190 *
191 * This means that reading a 32-bit word at address 0 returns the same
192 * value irrespective of the endian mode bit.
193 *
194 * Peripheral devices should be connected with the data bus reversed in
195 * "Big Endian" mode. ARM Application Note 61 is applicable, and is
196 * available from http://www.arm.com/.
197 *
198 * The following assumes that the data bus connectivity for big endian
199 * mode has been followed.
200 *
201 * Note that bit 0 is defined to be 32-bit word bit 0, not byte 0 bit 0.
202 */
203
204/*
205 * Little endian assembly bitops. nr = 0 -> byte 0 bit 0.
206 */
207extern void _set_bit_le(int nr, volatile unsigned long * p);
208extern void _clear_bit_le(int nr, volatile unsigned long * p);
209extern void _change_bit_le(int nr, volatile unsigned long * p);
210extern int _test_and_set_bit_le(int nr, volatile unsigned long * p);
211extern int _test_and_clear_bit_le(int nr, volatile unsigned long * p);
212extern int _test_and_change_bit_le(int nr, volatile unsigned long * p);
213extern int _find_first_zero_bit_le(const void * p, unsigned size);
214extern int _find_next_zero_bit_le(const void * p, int size, int offset);
215extern int _find_first_bit_le(const unsigned long *p, unsigned size);
216extern int _find_next_bit_le(const unsigned long *p, int size, int offset);
217
218/*
219 * Big endian assembly bitops. nr = 0 -> byte 3 bit 0.
220 */
221extern void _set_bit_be(int nr, volatile unsigned long * p);
222extern void _clear_bit_be(int nr, volatile unsigned long * p);
223extern void _change_bit_be(int nr, volatile unsigned long * p);
224extern int _test_and_set_bit_be(int nr, volatile unsigned long * p);
225extern int _test_and_clear_bit_be(int nr, volatile unsigned long * p);
226extern int _test_and_change_bit_be(int nr, volatile unsigned long * p);
227extern int _find_first_zero_bit_be(const void * p, unsigned size);
228extern int _find_next_zero_bit_be(const void * p, int size, int offset);
229extern int _find_first_bit_be(const unsigned long *p, unsigned size);
230extern int _find_next_bit_be(const unsigned long *p, int size, int offset);
231
232#ifndef CONFIG_SMP
233/*
234 * The __* form of bitops are non-atomic and may be reordered.
235 */
236#define ATOMIC_BITOP_LE(name,nr,p) \
237 (__builtin_constant_p(nr) ? \
238 ____atomic_##name(nr, p) : \
239 _##name##_le(nr,p))
240
241#define ATOMIC_BITOP_BE(name,nr,p) \
242 (__builtin_constant_p(nr) ? \
243 ____atomic_##name(nr, p) : \
244 _##name##_be(nr,p))
245#else
246#define ATOMIC_BITOP_LE(name,nr,p) _##name##_le(nr,p)
247#define ATOMIC_BITOP_BE(name,nr,p) _##name##_be(nr,p)
248#endif
249
250#define NONATOMIC_BITOP(name,nr,p) \
251 (____nonatomic_##name(nr, p))
252
253#ifndef __ARMEB__
254/*
255 * These are the little endian, atomic definitions.
256 */
257#define set_bit(nr,p) ATOMIC_BITOP_LE(set_bit,nr,p)
258#define clear_bit(nr,p) ATOMIC_BITOP_LE(clear_bit,nr,p)
259#define change_bit(nr,p) ATOMIC_BITOP_LE(change_bit,nr,p)
260#define test_and_set_bit(nr,p) ATOMIC_BITOP_LE(test_and_set_bit,nr,p)
261#define test_and_clear_bit(nr,p) ATOMIC_BITOP_LE(test_and_clear_bit,nr,p)
262#define test_and_change_bit(nr,p) ATOMIC_BITOP_LE(test_and_change_bit,nr,p)
263#define test_bit(nr,p) __test_bit(nr,p)
264#define find_first_zero_bit(p,sz) _find_first_zero_bit_le(p,sz)
265#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_le(p,sz,off)
266#define find_first_bit(p,sz) _find_first_bit_le(p,sz)
267#define find_next_bit(p,sz,off) _find_next_bit_le(p,sz,off)
268
269#define WORD_BITOFF_TO_LE(x) ((x))
270
271#else
272
273/*
274 * These are the big endian, atomic definitions.
275 */
276#define set_bit(nr,p) ATOMIC_BITOP_BE(set_bit,nr,p)
277#define clear_bit(nr,p) ATOMIC_BITOP_BE(clear_bit,nr,p)
278#define change_bit(nr,p) ATOMIC_BITOP_BE(change_bit,nr,p)
279#define test_and_set_bit(nr,p) ATOMIC_BITOP_BE(test_and_set_bit,nr,p)
280#define test_and_clear_bit(nr,p) ATOMIC_BITOP_BE(test_and_clear_bit,nr,p)
281#define test_and_change_bit(nr,p) ATOMIC_BITOP_BE(test_and_change_bit,nr,p)
282#define test_bit(nr,p) __test_bit(nr,p)
283#define find_first_zero_bit(p,sz) _find_first_zero_bit_be(p,sz)
284#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_be(p,sz,off)
285#define find_first_bit(p,sz) _find_first_bit_be(p,sz)
286#define find_next_bit(p,sz,off) _find_next_bit_be(p,sz,off)
287
288#define WORD_BITOFF_TO_LE(x) ((x) ^ 0x18)
289
290#endif
291
292#if __LINUX_ARM_ARCH__ < 5
293
294/*
295 * ffz = Find First Zero in word. Undefined if no zero exists,
296 * so code should check against ~0UL first..
297 */
298static inline unsigned long ffz(unsigned long word)
299{
300 int k;
301
302 word = ~word;
303 k = 31;
304 if (word & 0x0000ffff) { k -= 16; word <<= 16; }
305 if (word & 0x00ff0000) { k -= 8; word <<= 8; }
306 if (word & 0x0f000000) { k -= 4; word <<= 4; }
307 if (word & 0x30000000) { k -= 2; word <<= 2; }
308 if (word & 0x40000000) { k -= 1; }
309 return k;
310}
311
312/*
313 * ffz = Find First Zero in word. Undefined if no zero exists,
314 * so code should check against ~0UL first..
315 */
316static inline unsigned long __ffs(unsigned long word)
317{
318 int k;
319
320 k = 31;
321 if (word & 0x0000ffff) { k -= 16; word <<= 16; }
322 if (word & 0x00ff0000) { k -= 8; word <<= 8; }
323 if (word & 0x0f000000) { k -= 4; word <<= 4; }
324 if (word & 0x30000000) { k -= 2; word <<= 2; }
325 if (word & 0x40000000) { k -= 1; }
326 return k;
327}
328
329/*
330 * fls: find last bit set.
331 */
332
333#define fls(x) generic_fls(x)
334
335/*
336 * ffs: find first bit set. This is defined the same way as
337 * the libc and compiler builtin ffs routines, therefore
338 * differs in spirit from the above ffz (man ffs).
339 */
340
341#define ffs(x) generic_ffs(x)
342
343#else
344
345/*
346 * On ARMv5 and above those functions can be implemented around
347 * the clz instruction for much better code efficiency.
348 */
349
350static __inline__ int generic_fls(int x);
351#define fls(x) \
352 ( __builtin_constant_p(x) ? generic_fls(x) : \
353 ({ int __r; asm("clz\t%0, %1" : "=r"(__r) : "r"(x) : "cc"); 32-__r; }) )
354#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })
355#define __ffs(x) (ffs(x) - 1)
356#define ffz(x) __ffs( ~(x) )
357
358#endif
359
360/*
361 * Find first bit set in a 168-bit bitmap, where the first
362 * 128 bits are unlikely to be set.
363 */
364static inline int sched_find_first_bit(const unsigned long *b)
365{
366 unsigned long v;
367 unsigned int off;
368
369 for (off = 0; v = b[off], off < 4; off++) {
370 if (unlikely(v))
371 break;
372 }
373 return __ffs(v) + off * 32;
374}
375
376/*
377 * hweightN: returns the hamming weight (i.e. the number
378 * of bits set) of a N-bit word
379 */
380
381#define hweight32(x) generic_hweight32(x)
382#define hweight16(x) generic_hweight16(x)
383#define hweight8(x) generic_hweight8(x)
384
385/*
386 * Ext2 is defined to use little-endian byte ordering.
387 * These do not need to be atomic.
388 */
389#define ext2_set_bit(nr,p) \
390 __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
391#define ext2_set_bit_atomic(lock,nr,p) \
392 test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
393#define ext2_clear_bit(nr,p) \
394 __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
395#define ext2_clear_bit_atomic(lock,nr,p) \
396 test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
397#define ext2_test_bit(nr,p) \
398 __test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
399#define ext2_find_first_zero_bit(p,sz) \
400 _find_first_zero_bit_le(p,sz)
401#define ext2_find_next_zero_bit(p,sz,off) \
402 _find_next_zero_bit_le(p,sz,off)
403
404/*
405 * Minix is defined to use little-endian byte ordering.
406 * These do not need to be atomic.
407 */
408#define minix_set_bit(nr,p) \
409 __set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
410#define minix_test_bit(nr,p) \
411 __test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
412#define minix_test_and_set_bit(nr,p) \
413 __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
414#define minix_test_and_clear_bit(nr,p) \
415 __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
416#define minix_find_first_zero_bit(p,sz) \
417 _find_first_zero_bit_le(p,sz)
418
419#endif /* __KERNEL__ */
420
421#endif /* _ARM_BITOPS_H */