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Diffstat (limited to 'include/asm-arm/bitops.h')
| -rw-r--r-- | include/asm-arm/bitops.h | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/include/asm-arm/bitops.h b/include/asm-arm/bitops.h new file mode 100644 index 000000000000..4edd4dc40c5b --- /dev/null +++ b/include/asm-arm/bitops.h @@ -0,0 +1,416 @@ +/* + * Copyright 1995, Russell King. + * Various bits and pieces copyrights include: + * Linus Torvalds (test_bit). + * Big endian support: Copyright 2001, Nicolas Pitre + * reworked by rmk. + * + * bit 0 is the LSB of an "unsigned long" quantity. + * + * Please note that the code in this file should never be included + * from user space. Many of these are not implemented in assembler + * since they would be too costly. Also, they require privileged + * instructions (which are not available from user mode) to ensure + * that they are atomic. + */ + +#ifndef __ASM_ARM_BITOPS_H +#define __ASM_ARM_BITOPS_H + +#ifdef __KERNEL__ + +#include <asm/system.h> + +#define smp_mb__before_clear_bit() do { } while (0) +#define smp_mb__after_clear_bit() do { } while (0) + +/* + * These functions are the basis of our bit ops. + * + * First, the atomic bitops. These use native endian. + */ +static inline void ____atomic_set_bit(unsigned int bit, volatile unsigned long *p) +{ + unsigned long flags; + unsigned long mask = 1UL << (bit & 31); + + p += bit >> 5; + + local_irq_save(flags); + *p |= mask; + local_irq_restore(flags); +} + +static inline void ____atomic_clear_bit(unsigned int bit, volatile unsigned long *p) +{ + unsigned long flags; + unsigned long mask = 1UL << (bit & 31); + + p += bit >> 5; + + local_irq_save(flags); + *p &= ~mask; + local_irq_restore(flags); +} + +static inline void ____atomic_change_bit(unsigned int bit, volatile unsigned long *p) +{ + unsigned long flags; + unsigned long mask = 1UL << (bit & 31); + + p += bit >> 5; + + local_irq_save(flags); + *p ^= mask; + local_irq_restore(flags); +} + +static inline int +____atomic_test_and_set_bit(unsigned int bit, volatile unsigned long *p) +{ + unsigned long flags; + unsigned int res; + unsigned long mask = 1UL << (bit & 31); + + p += bit >> 5; + + local_irq_save(flags); + res = *p; + *p = res | mask; + local_irq_restore(flags); + + return res & mask; +} + +static inline int +____atomic_test_and_clear_bit(unsigned int bit, volatile unsigned long *p) +{ + unsigned long flags; + unsigned int res; + unsigned long mask = 1UL << (bit & 31); + + p += bit >> 5; + + local_irq_save(flags); + res = *p; + *p = res & ~mask; + local_irq_restore(flags); + + return res & mask; +} + +static inline int +____atomic_test_and_change_bit(unsigned int bit, volatile unsigned long *p) +{ + unsigned long flags; + unsigned int res; + unsigned long mask = 1UL << (bit & 31); + + p += bit >> 5; + + local_irq_save(flags); + res = *p; + *p = res ^ mask; + local_irq_restore(flags); + + return res & mask; +} + +/* + * Now the non-atomic variants. We let the compiler handle all + * optimisations for these. These are all _native_ endian. + */ +static inline void __set_bit(int nr, volatile unsigned long *p) +{ + p[nr >> 5] |= (1UL << (nr & 31)); +} + +static inline void __clear_bit(int nr, volatile unsigned long *p) +{ + p[nr >> 5] &= ~(1UL << (nr & 31)); +} + +static inline void __change_bit(int nr, volatile unsigned long *p) +{ + p[nr >> 5] ^= (1UL << (nr & 31)); +} + +static inline int __test_and_set_bit(int nr, volatile unsigned long *p) +{ + unsigned long oldval, mask = 1UL << (nr & 31); + + p += nr >> 5; + + oldval = *p; + *p = oldval | mask; + return oldval & mask; +} + +static inline int __test_and_clear_bit(int nr, volatile unsigned long *p) +{ + unsigned long oldval, mask = 1UL << (nr & 31); + + p += nr >> 5; + + oldval = *p; + *p = oldval & ~mask; + return oldval & mask; +} + +static inline int __test_and_change_bit(int nr, volatile unsigned long *p) +{ + unsigned long oldval, mask = 1UL << (nr & 31); + + p += nr >> 5; + + oldval = *p; + *p = oldval ^ mask; + return oldval & mask; +} + +/* + * This routine doesn't need to be atomic. + */ +static inline int __test_bit(int nr, const volatile unsigned long * p) +{ + return (p[nr >> 5] >> (nr & 31)) & 1UL; +} + +/* + * A note about Endian-ness. + * ------------------------- + * + * When the ARM is put into big endian mode via CR15, the processor + * merely swaps the order of bytes within words, thus: + * + * ------------ physical data bus bits ----------- + * D31 ... D24 D23 ... D16 D15 ... D8 D7 ... D0 + * little byte 3 byte 2 byte 1 byte 0 + * big byte 0 byte 1 byte 2 byte 3 + * + * This means that reading a 32-bit word at address 0 returns the same + * value irrespective of the endian mode bit. + * + * Peripheral devices should be connected with the data bus reversed in + * "Big Endian" mode. ARM Application Note 61 is applicable, and is + * available from http://www.arm.com/. + * + * The following assumes that the data bus connectivity for big endian + * mode has been followed. + * + * Note that bit 0 is defined to be 32-bit word bit 0, not byte 0 bit 0. + */ + +/* + * Little endian assembly bitops. nr = 0 -> byte 0 bit 0. + */ +extern void _set_bit_le(int nr, volatile unsigned long * p); +extern void _clear_bit_le(int nr, volatile unsigned long * p); +extern void _change_bit_le(int nr, volatile unsigned long * p); +extern int _test_and_set_bit_le(int nr, volatile unsigned long * p); +extern int _test_and_clear_bit_le(int nr, volatile unsigned long * p); +extern int _test_and_change_bit_le(int nr, volatile unsigned long * p); +extern int _find_first_zero_bit_le(const void * p, unsigned size); +extern int _find_next_zero_bit_le(const void * p, int size, int offset); +extern int _find_first_bit_le(const unsigned long *p, unsigned size); +extern int _find_next_bit_le(const unsigned long *p, int size, int offset); + +/* + * Big endian assembly bitops. nr = 0 -> byte 3 bit 0. + */ +extern void _set_bit_be(int nr, volatile unsigned long * p); +extern void _clear_bit_be(int nr, volatile unsigned long * p); +extern void _change_bit_be(int nr, volatile unsigned long * p); +extern int _test_and_set_bit_be(int nr, volatile unsigned long * p); +extern int _test_and_clear_bit_be(int nr, volatile unsigned long * p); +extern int _test_and_change_bit_be(int nr, volatile unsigned long * p); +extern int _find_first_zero_bit_be(const void * p, unsigned size); +extern int _find_next_zero_bit_be(const void * p, int size, int offset); +extern int _find_first_bit_be(const unsigned long *p, unsigned size); +extern int _find_next_bit_be(const unsigned long *p, int size, int offset); + +/* + * The __* form of bitops are non-atomic and may be reordered. + */ +#define ATOMIC_BITOP_LE(name,nr,p) \ + (__builtin_constant_p(nr) ? \ + ____atomic_##name(nr, p) : \ + _##name##_le(nr,p)) + +#define ATOMIC_BITOP_BE(name,nr,p) \ + (__builtin_constant_p(nr) ? \ + ____atomic_##name(nr, p) : \ + _##name##_be(nr,p)) + +#define NONATOMIC_BITOP(name,nr,p) \ + (____nonatomic_##name(nr, p)) + +#ifndef __ARMEB__ +/* + * These are the little endian, atomic definitions. + */ +#define set_bit(nr,p) ATOMIC_BITOP_LE(set_bit,nr,p) +#define clear_bit(nr,p) ATOMIC_BITOP_LE(clear_bit,nr,p) +#define change_bit(nr,p) ATOMIC_BITOP_LE(change_bit,nr,p) +#define test_and_set_bit(nr,p) ATOMIC_BITOP_LE(test_and_set_bit,nr,p) +#define test_and_clear_bit(nr,p) ATOMIC_BITOP_LE(test_and_clear_bit,nr,p) +#define test_and_change_bit(nr,p) ATOMIC_BITOP_LE(test_and_change_bit,nr,p) +#define test_bit(nr,p) __test_bit(nr,p) +#define find_first_zero_bit(p,sz) _find_first_zero_bit_le(p,sz) +#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_le(p,sz,off) +#define find_first_bit(p,sz) _find_first_bit_le(p,sz) +#define find_next_bit(p,sz,off) _find_next_bit_le(p,sz,off) + +#define WORD_BITOFF_TO_LE(x) ((x)) + +#else + +/* + * These are the big endian, atomic definitions. + */ +#define set_bit(nr,p) ATOMIC_BITOP_BE(set_bit,nr,p) +#define clear_bit(nr,p) ATOMIC_BITOP_BE(clear_bit,nr,p) +#define change_bit(nr,p) ATOMIC_BITOP_BE(change_bit,nr,p) +#define test_and_set_bit(nr,p) ATOMIC_BITOP_BE(test_and_set_bit,nr,p) +#define test_and_clear_bit(nr,p) ATOMIC_BITOP_BE(test_and_clear_bit,nr,p) +#define test_and_change_bit(nr,p) ATOMIC_BITOP_BE(test_and_change_bit,nr,p) +#define test_bit(nr,p) __test_bit(nr,p) +#define find_first_zero_bit(p,sz) _find_first_zero_bit_be(p,sz) +#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_be(p,sz,off) +#define find_first_bit(p,sz) _find_first_bit_be(p,sz) +#define find_next_bit(p,sz,off) _find_next_bit_be(p,sz,off) + +#define WORD_BITOFF_TO_LE(x) ((x) ^ 0x18) + +#endif + +#if __LINUX_ARM_ARCH__ < 5 + +/* + * ffz = Find First Zero in word. Undefined if no zero exists, + * so code should check against ~0UL first.. + */ +static inline unsigned long ffz(unsigned long word) +{ + int k; + + word = ~word; + k = 31; + if (word & 0x0000ffff) { k -= 16; word <<= 16; } + if (word & 0x00ff0000) { k -= 8; word <<= 8; } + if (word & 0x0f000000) { k -= 4; word <<= 4; } + if (word & 0x30000000) { k -= 2; word <<= 2; } + if (word & 0x40000000) { k -= 1; } + return k; +} + +/* + * ffz = Find First Zero in word. Undefined if no zero exists, + * so code should check against ~0UL first.. + */ +static inline unsigned long __ffs(unsigned long word) +{ + int k; + + k = 31; + if (word & 0x0000ffff) { k -= 16; word <<= 16; } + if (word & 0x00ff0000) { k -= 8; word <<= 8; } + if (word & 0x0f000000) { k -= 4; word <<= 4; } + if (word & 0x30000000) { k -= 2; word <<= 2; } + if (word & 0x40000000) { k -= 1; } + return k; +} + +/* + * fls: find last bit set. + */ + +#define fls(x) generic_fls(x) + +/* + * ffs: find first bit set. This is defined the same way as + * the libc and compiler builtin ffs routines, therefore + * differs in spirit from the above ffz (man ffs). + */ + +#define ffs(x) generic_ffs(x) + +#else + +/* + * On ARMv5 and above those functions can be implemented around + * the clz instruction for much better code efficiency. + */ + +static __inline__ int generic_fls(int x); +#define fls(x) \ + ( __builtin_constant_p(x) ? generic_fls(x) : \ + ({ int __r; asm("clz\t%0, %1" : "=r"(__r) : "r"(x) : "cc"); 32-__r; }) ) +#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); }) +#define __ffs(x) (ffs(x) - 1) +#define ffz(x) __ffs( ~(x) ) + +#endif + +/* + * Find first bit set in a 168-bit bitmap, where the first + * 128 bits are unlikely to be set. + */ +static inline int sched_find_first_bit(const unsigned long *b) +{ + unsigned long v; + unsigned int off; + + for (off = 0; v = b[off], off < 4; off++) { + if (unlikely(v)) + break; + } + return __ffs(v) + off * 32; +} + +/* + * hweightN: returns the hamming weight (i.e. the number + * of bits set) of a N-bit word + */ + +#define hweight32(x) generic_hweight32(x) +#define hweight16(x) generic_hweight16(x) +#define hweight8(x) generic_hweight8(x) + +/* + * Ext2 is defined to use little-endian byte ordering. + * These do not need to be atomic. + */ +#define ext2_set_bit(nr,p) \ + __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p)) +#define ext2_set_bit_atomic(lock,nr,p) \ + test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p)) +#define ext2_clear_bit(nr,p) \ + __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p)) +#define ext2_clear_bit_atomic(lock,nr,p) \ + test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p)) +#define ext2_test_bit(nr,p) \ + __test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p)) +#define ext2_find_first_zero_bit(p,sz) \ + _find_first_zero_bit_le(p,sz) +#define ext2_find_next_zero_bit(p,sz,off) \ + _find_next_zero_bit_le(p,sz,off) + +/* + * Minix is defined to use little-endian byte ordering. + * These do not need to be atomic. + */ +#define minix_set_bit(nr,p) \ + __set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p)) +#define minix_test_bit(nr,p) \ + __test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p)) +#define minix_test_and_set_bit(nr,p) \ + __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p)) +#define minix_test_and_clear_bit(nr,p) \ + __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p)) +#define minix_find_first_zero_bit(p,sz) \ + _find_first_zero_bit_le(p,sz) + +#endif /* __KERNEL__ */ + +#endif /* _ARM_BITOPS_H */ |
