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Diffstat (limited to 'arch/arm/include/asm/bitops.h')
| -rw-r--r-- | arch/arm/include/asm/bitops.h | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h new file mode 100644 index 000000000..714440fa2 --- /dev/null +++ b/arch/arm/include/asm/bitops.h @@ -0,0 +1,278 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * 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__ + +#ifndef _LINUX_BITOPS_H +#error only <linux/bitops.h> can be included directly +#endif + +#include <linux/compiler.h> +#include <linux/irqflags.h> +#include <asm/barrier.h> + +/* + * 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 = BIT_MASK(bit); + + p += BIT_WORD(bit); + + raw_local_irq_save(flags); + *p |= mask; + raw_local_irq_restore(flags); +} + +static inline void ____atomic_clear_bit(unsigned int bit, volatile unsigned long *p) +{ + unsigned long flags; + unsigned long mask = BIT_MASK(bit); + + p += BIT_WORD(bit); + + raw_local_irq_save(flags); + *p &= ~mask; + raw_local_irq_restore(flags); +} + +static inline void ____atomic_change_bit(unsigned int bit, volatile unsigned long *p) +{ + unsigned long flags; + unsigned long mask = BIT_MASK(bit); + + p += BIT_WORD(bit); + + raw_local_irq_save(flags); + *p ^= mask; + raw_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 = BIT_MASK(bit); + + p += BIT_WORD(bit); + + raw_local_irq_save(flags); + res = *p; + *p = res | mask; + raw_local_irq_restore(flags); + + return (res & mask) != 0; +} + +static inline int +____atomic_test_and_clear_bit(unsigned int bit, volatile unsigned long *p) +{ + unsigned long flags; + unsigned int res; + unsigned long mask = BIT_MASK(bit); + + p += BIT_WORD(bit); + + raw_local_irq_save(flags); + res = *p; + *p = res & ~mask; + raw_local_irq_restore(flags); + + return (res & mask) != 0; +} + +static inline int +____atomic_test_and_change_bit(unsigned int bit, volatile unsigned long *p) +{ + unsigned long flags; + unsigned int res; + unsigned long mask = BIT_MASK(bit); + + p += BIT_WORD(bit); + + raw_local_irq_save(flags); + res = *p; + *p = res ^ mask; + raw_local_irq_restore(flags); + + return (res & mask) != 0; +} + +#include <asm-generic/bitops/non-atomic.h> + +/* + * 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. + */ + +/* + * Native endian assembly bitops. nr = 0 -> word 0 bit 0. + */ +extern void _set_bit(int nr, volatile unsigned long * p); +extern void _clear_bit(int nr, volatile unsigned long * p); +extern void _change_bit(int nr, volatile unsigned long * p); +extern int _test_and_set_bit(int nr, volatile unsigned long * p); +extern int _test_and_clear_bit(int nr, volatile unsigned long * p); +extern int _test_and_change_bit(int nr, volatile unsigned long * p); + +/* + * Little endian assembly bitops. nr = 0 -> byte 0 bit 0. + */ +unsigned long _find_first_zero_bit_le(const unsigned long *p, unsigned long size); +unsigned long _find_next_zero_bit_le(const unsigned long *p, + unsigned long size, unsigned long offset); +unsigned long _find_first_bit_le(const unsigned long *p, unsigned long size); +unsigned long _find_next_bit_le(const unsigned long *p, unsigned long size, unsigned long offset); + +/* + * Big endian assembly bitops. nr = 0 -> byte 3 bit 0. + */ +unsigned long _find_first_zero_bit_be(const unsigned long *p, unsigned long size); +unsigned long _find_next_zero_bit_be(const unsigned long *p, + unsigned long size, unsigned long offset); +unsigned long _find_first_bit_be(const unsigned long *p, unsigned long size); +unsigned long _find_next_bit_be(const unsigned long *p, unsigned long size, unsigned long offset); + +#ifndef CONFIG_SMP +/* + * The __* form of bitops are non-atomic and may be reordered. + */ +#define ATOMIC_BITOP(name,nr,p) \ + (__builtin_constant_p(nr) ? ____atomic_##name(nr, p) : _##name(nr,p)) +#else +#define ATOMIC_BITOP(name,nr,p) _##name(nr,p) +#endif + +/* + * Native endian atomic definitions. + */ +#define set_bit(nr,p) ATOMIC_BITOP(set_bit,nr,p) +#define clear_bit(nr,p) ATOMIC_BITOP(clear_bit,nr,p) +#define change_bit(nr,p) ATOMIC_BITOP(change_bit,nr,p) +#define test_and_set_bit(nr,p) ATOMIC_BITOP(test_and_set_bit,nr,p) +#define test_and_clear_bit(nr,p) ATOMIC_BITOP(test_and_clear_bit,nr,p) +#define test_and_change_bit(nr,p) ATOMIC_BITOP(test_and_change_bit,nr,p) + +#ifndef __ARMEB__ +/* + * These are the little endian, atomic definitions. + */ +#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) + +#else +/* + * These are the big endian, atomic definitions. + */ +#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) + +#endif + +#if __LINUX_ARM_ARCH__ < 5 + +#include <asm-generic/bitops/__fls.h> +#include <asm-generic/bitops/__ffs.h> +#include <asm-generic/bitops/fls.h> +#include <asm-generic/bitops/ffs.h> + +#else + +/* + * On ARMv5 and above, the gcc built-ins may rely on the clz instruction + * and produce optimal inlined code in all cases. On ARMv7 it is even + * better by also using the rbit instruction. + */ +#include <asm-generic/bitops/builtin-__fls.h> +#include <asm-generic/bitops/builtin-__ffs.h> +#include <asm-generic/bitops/builtin-fls.h> +#include <asm-generic/bitops/builtin-ffs.h> + +#endif + +#include <asm-generic/bitops/ffz.h> + +#include <asm-generic/bitops/fls64.h> + +#include <asm-generic/bitops/sched.h> +#include <asm-generic/bitops/hweight.h> +#include <asm-generic/bitops/lock.h> + +#ifdef __ARMEB__ + +static inline int find_first_zero_bit_le(const void *p, unsigned size) +{ + return _find_first_zero_bit_le(p, size); +} +#define find_first_zero_bit_le find_first_zero_bit_le + +static inline int find_next_zero_bit_le(const void *p, int size, int offset) +{ + return _find_next_zero_bit_le(p, size, offset); +} +#define find_next_zero_bit_le find_next_zero_bit_le + +static inline int find_next_bit_le(const void *p, int size, int offset) +{ + return _find_next_bit_le(p, size, offset); +} +#define find_next_bit_le find_next_bit_le + +#endif + +#include <asm-generic/bitops/le.h> + +/* + * Ext2 is defined to use little-endian byte ordering. + */ +#include <asm-generic/bitops/ext2-atomic-setbit.h> + +#endif /* __KERNEL__ */ + +#endif /* _ARM_BITOPS_H */ |