/* * 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() mb() #define smp_mb__after_clear_bit() mb() /* * 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); #ifndef CONFIG_SMP /* * 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)) #else #define ATOMIC_BITOP_LE(name,nr,p) _##name##_le(nr,p) #define ATOMIC_BITOP_BE(name,nr,p) _##name##_be(nr,p) #endif #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 */