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