/* SPDX-License-Identifier: GPL-2.0-only */


#ifndef _LINUX_BITFIELD_H
#define _LINUX_BITFIELD_H

#include <linux/build_bug.h>
#include <asm/byteorder.h>



#define __bf_shf(x) (__builtin_ffsll(x) - 1)

#define __scalar_type_to_unsigned_cases(type)				\
		unsigned type:	(unsigned type)0,			\
		signed type:	(unsigned type)0

#define __unsigned_scalar_typeof(x) typeof(				\
		_Generic((x),						\
			char:	(unsigned char)0,			\
			__scalar_type_to_unsigned_cases(char),		\
			__scalar_type_to_unsigned_cases(short),		\
			__scalar_type_to_unsigned_cases(int),		\
			__scalar_type_to_unsigned_cases(long),		\
			__scalar_type_to_unsigned_cases(long long),	\
			default: (x)))

#define __bf_cast_unsigned(type, x)	((__unsigned_scalar_typeof(type))(x))

#define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx)			\
	({								\
		BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask),		\
				 _pfx "mask is not constant");		\
		BUILD_BUG_ON_MSG((_mask) == 0, _pfx "mask is zero");	\
		BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ?		\
				 ~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \
				 _pfx "value too large for the field"); \
		BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) >	\
				 __bf_cast_unsigned(_reg, ~0ull),	\
				 _pfx "type of reg too small for mask"); \
		__BUILD_BUG_ON_NOT_POWER_OF_2((_mask) +			\
					      (1ULL << __bf_shf(_mask))); \
	})


#define FIELD_MAX(_mask)						\
	({								\
		__BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_MAX: ");	\
		(typeof(_mask))((_mask) >> __bf_shf(_mask));		\
	})


#define FIELD_FIT(_mask, _val)						\
	({								\
		__BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_FIT: ");	\
		!((((typeof(_mask))_val) << __bf_shf(_mask)) & ~(_mask)); \
	})


#define FIELD_PREP(_mask, _val)						\
	({								\
		__BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");	\
		((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask);	\
	})


#define FIELD_GET(_mask, _reg)						\
	({								\
		__BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: ");	\
		(typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask));	\
	})

extern void __compiletime_error("value doesn't fit into mask")
__field_overflow(void);
extern void __compiletime_error("bad bitfield mask")
__bad_mask(void);
static __always_inline u64 field_multiplier(u64 field)
{
	if ((field | (field - 1)) & ((field | (field - 1)) + 1))
		__bad_mask();
	return field & -field;
}
static __always_inline u64 field_mask(u64 field)
{
	return field / field_multiplier(field);
}
#define field_max(field)	((typeof(field))field_mask(field))
#define ____MAKE_OP(type,base,to,from)					\
static __always_inline __##type type##_encode_bits(base v, base field)	\
{									\
	if (__builtin_constant_p(v) && (v & ~field_mask(field)))	\
		__field_overflow();					\
	return to((v & field_mask(field)) * field_multiplier(field));	\
}									\
static __always_inline __##type type##_replace_bits(__##type old,	\
					base val, base field)		\
{									\
	return (old & ~to(field)) | type##_encode_bits(val, field);	\
}									\
static __always_inline void type##p_replace_bits(__##type *p,		\
					base val, base field)		\
{									\
	*p = (*p & ~to(field)) | type##_encode_bits(val, field);	\
}									\
static __always_inline base type##_get_bits(__##type v, base field)	\
{									\
	return (from(v) & field)/field_multiplier(field);		\
}
#define __MAKE_OP(size)							\
	____MAKE_OP(le##size,u##size,cpu_to_le##size,le##size##_to_cpu)	\
	____MAKE_OP(be##size,u##size,cpu_to_be##size,be##size##_to_cpu)	\
	____MAKE_OP(u##size,u##size,,)
____MAKE_OP(u8,u8,,)
__MAKE_OP(16)
__MAKE_OP(32)
__MAKE_OP(64)
#undef __MAKE_OP
#undef ____MAKE_OP

#endif
