1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Copyright 1995, Russell King. 4 * Various bits and pieces copyrights include: 5 * Linus Torvalds (test_bit). 6 * Big endian support: Copyright 2001, Nicolas Pitre 7 * reworked by rmk. 8 * 9 * bit 0 is the LSB of an "unsigned long" quantity. 10 * 11 * Please note that the code in this file should never be included 12 * from user space. Many of these are not implemented in assembler 13 * since they would be too costly. Also, they require privileged 14 * instructions (which are not available from user mode) to ensure 15 * that they are atomic. 16 */ 17 18 #ifndef __ASM_ARM_BITOPS_H 19 #define __ASM_ARM_BITOPS_H 20 21 #ifdef __KERNEL__ 22 23 #ifndef _LINUX_BITOPS_H 24 #error only <linux/bitops.h> can be included directly 25 #endif 26 27 #include <linux/compiler.h> 28 #include <linux/irqflags.h> 29 #include <asm/barrier.h> 30 31 /* 32 * These functions are the basis of our bit ops. 33 * 34 * First, the atomic bitops. These use native endian. 35 */ 36 static inline void ____atomic_set_bit(unsigned int bit, volatile unsigned long *p) 37 { 38 unsigned long flags; 39 unsigned long mask = BIT_MASK(bit); 40 41 p += BIT_WORD(bit); 42 43 raw_local_irq_save(flags); 44 *p |= mask; 45 raw_local_irq_restore(flags); 46 } 47 48 static inline void ____atomic_clear_bit(unsigned int bit, volatile unsigned long *p) 49 { 50 unsigned long flags; 51 unsigned long mask = BIT_MASK(bit); 52 53 p += BIT_WORD(bit); 54 55 raw_local_irq_save(flags); 56 *p &= ~mask; 57 raw_local_irq_restore(flags); 58 } 59 60 static inline void ____atomic_change_bit(unsigned int bit, volatile unsigned long *p) 61 { 62 unsigned long flags; 63 unsigned long mask = BIT_MASK(bit); 64 65 p += BIT_WORD(bit); 66 67 raw_local_irq_save(flags); 68 *p ^= mask; 69 raw_local_irq_restore(flags); 70 } 71 72 static inline int 73 ____atomic_test_and_set_bit(unsigned int bit, volatile unsigned long *p) 74 { 75 unsigned long flags; 76 unsigned int res; 77 unsigned long mask = BIT_MASK(bit); 78 79 p += BIT_WORD(bit); 80 81 raw_local_irq_save(flags); 82 res = *p; 83 *p = res | mask; 84 raw_local_irq_restore(flags); 85 86 return (res & mask) != 0; 87 } 88 89 static inline int 90 ____atomic_test_and_clear_bit(unsigned int bit, volatile unsigned long *p) 91 { 92 unsigned long flags; 93 unsigned int res; 94 unsigned long mask = BIT_MASK(bit); 95 96 p += BIT_WORD(bit); 97 98 raw_local_irq_save(flags); 99 res = *p; 100 *p = res & ~mask; 101 raw_local_irq_restore(flags); 102 103 return (res & mask) != 0; 104 } 105 106 static inline int 107 ____atomic_test_and_change_bit(unsigned int bit, volatile unsigned long *p) 108 { 109 unsigned long flags; 110 unsigned int res; 111 unsigned long mask = BIT_MASK(bit); 112 113 p += BIT_WORD(bit); 114 115 raw_local_irq_save(flags); 116 res = *p; 117 *p = res ^ mask; 118 raw_local_irq_restore(flags); 119 120 return (res & mask) != 0; 121 } 122 123 #include <asm-generic/bitops/non-atomic.h> 124 125 /* 126 * A note about Endian-ness. 127 * ------------------------- 128 * 129 * When the ARM is put into big endian mode via CR15, the processor 130 * merely swaps the order of bytes within words, thus: 131 * 132 * ------------ physical data bus bits ----------- 133 * D31 ... D24 D23 ... D16 D15 ... D8 D7 ... D0 134 * little byte 3 byte 2 byte 1 byte 0 135 * big byte 0 byte 1 byte 2 byte 3 136 * 137 * This means that reading a 32-bit word at address 0 returns the same 138 * value irrespective of the endian mode bit. 139 * 140 * Peripheral devices should be connected with the data bus reversed in 141 * "Big Endian" mode. ARM Application Note 61 is applicable, and is 142 * available from http://www.arm.com/. 143 * 144 * The following assumes that the data bus connectivity for big endian 145 * mode has been followed. 146 * 147 * Note that bit 0 is defined to be 32-bit word bit 0, not byte 0 bit 0. 148 */ 149 150 /* 151 * Native endian assembly bitops. nr = 0 -> word 0 bit 0. 152 */ 153 extern void _set_bit(int nr, volatile unsigned long * p); 154 extern void _clear_bit(int nr, volatile unsigned long * p); 155 extern void _change_bit(int nr, volatile unsigned long * p); 156 extern int _test_and_set_bit(int nr, volatile unsigned long * p); 157 extern int _test_and_clear_bit(int nr, volatile unsigned long * p); 158 extern int _test_and_change_bit(int nr, volatile unsigned long * p); 159 160 /* 161 * Little endian assembly bitops. nr = 0 -> byte 0 bit 0. 162 */ 163 unsigned long _find_first_zero_bit_le(const unsigned long *p, unsigned long size); 164 unsigned long _find_next_zero_bit_le(const unsigned long *p, 165 unsigned long size, unsigned long offset); 166 unsigned long _find_first_bit_le(const unsigned long *p, unsigned long size); 167 unsigned long _find_next_bit_le(const unsigned long *p, unsigned long size, unsigned long offset); 168 169 /* 170 * Big endian assembly bitops. nr = 0 -> byte 3 bit 0. 171 */ 172 unsigned long _find_first_zero_bit_be(const unsigned long *p, unsigned long size); 173 unsigned long _find_next_zero_bit_be(const unsigned long *p, 174 unsigned long size, unsigned long offset); 175 unsigned long _find_first_bit_be(const unsigned long *p, unsigned long size); 176 unsigned long _find_next_bit_be(const unsigned long *p, unsigned long size, unsigned long offset); 177 178 #ifndef CONFIG_SMP 179 /* 180 * The __* form of bitops are non-atomic and may be reordered. 181 */ 182 #define ATOMIC_BITOP(name,nr,p) \ 183 (__builtin_constant_p(nr) ? ____atomic_##name(nr, p) : _##name(nr,p)) 184 #else 185 #define ATOMIC_BITOP(name,nr,p) _##name(nr,p) 186 #endif 187 188 /* 189 * Native endian atomic definitions. 190 */ 191 #define set_bit(nr,p) ATOMIC_BITOP(set_bit,nr,p) 192 #define clear_bit(nr,p) ATOMIC_BITOP(clear_bit,nr,p) 193 #define change_bit(nr,p) ATOMIC_BITOP(change_bit,nr,p) 194 #define test_and_set_bit(nr,p) ATOMIC_BITOP(test_and_set_bit,nr,p) 195 #define test_and_clear_bit(nr,p) ATOMIC_BITOP(test_and_clear_bit,nr,p) 196 #define test_and_change_bit(nr,p) ATOMIC_BITOP(test_and_change_bit,nr,p) 197 198 #ifndef __ARMEB__ 199 /* 200 * These are the little endian, atomic definitions. 201 */ 202 #define find_first_zero_bit(p,sz) _find_first_zero_bit_le(p,sz) 203 #define find_next_zero_bit(p,sz,off) _find_next_zero_bit_le(p,sz,off) 204 #define find_first_bit(p,sz) _find_first_bit_le(p,sz) 205 #define find_next_bit(p,sz,off) _find_next_bit_le(p,sz,off) 206 207 #else 208 /* 209 * These are the big endian, atomic definitions. 210 */ 211 #define find_first_zero_bit(p,sz) _find_first_zero_bit_be(p,sz) 212 #define find_next_zero_bit(p,sz,off) _find_next_zero_bit_be(p,sz,off) 213 #define find_first_bit(p,sz) _find_first_bit_be(p,sz) 214 #define find_next_bit(p,sz,off) _find_next_bit_be(p,sz,off) 215 216 #endif 217 218 #if __LINUX_ARM_ARCH__ < 5 219 220 #include <asm-generic/bitops/__fls.h> 221 #include <asm-generic/bitops/__ffs.h> 222 #include <asm-generic/bitops/fls.h> 223 #include <asm-generic/bitops/ffs.h> 224 225 #else 226 227 /* 228 * On ARMv5 and above, the gcc built-ins may rely on the clz instruction 229 * and produce optimal inlined code in all cases. On ARMv7 it is even 230 * better by also using the rbit instruction. 231 */ 232 #include <asm-generic/bitops/builtin-__fls.h> 233 #include <asm-generic/bitops/builtin-__ffs.h> 234 #include <asm-generic/bitops/builtin-fls.h> 235 #include <asm-generic/bitops/builtin-ffs.h> 236 237 #endif 238 239 #include <asm-generic/bitops/ffz.h> 240 241 #include <asm-generic/bitops/fls64.h> 242 243 #include <asm-generic/bitops/sched.h> 244 #include <asm-generic/bitops/hweight.h> 245 #include <asm-generic/bitops/lock.h> 246 247 #ifdef __ARMEB__ 248 249 static inline int find_first_zero_bit_le(const void *p, unsigned size) 250 { 251 return _find_first_zero_bit_le(p, size); 252 } 253 #define find_first_zero_bit_le find_first_zero_bit_le 254 255 static inline int find_next_zero_bit_le(const void *p, int size, int offset) 256 { 257 return _find_next_zero_bit_le(p, size, offset); 258 } 259 #define find_next_zero_bit_le find_next_zero_bit_le 260 261 static inline int find_next_bit_le(const void *p, int size, int offset) 262 { 263 return _find_next_bit_le(p, size, offset); 264 } 265 #define find_next_bit_le find_next_bit_le 266 267 #endif 268 269 #include <asm-generic/bitops/le.h> 270 271 /* 272 * Ext2 is defined to use little-endian byte ordering. 273 */ 274 #include <asm-generic/bitops/ext2-atomic-setbit.h> 275 276 #endif /* __KERNEL__ */ 277 278 #endif /* _ARM_BITOPS_H */ 279