githubmirror/ndctl

util/bitmap.h
119 строк4 KB
Vishal Verma
libcxl: add GET_HEALTH_INFO mailbox command and accessors
10 дек 2021, 00:06
10 дек 2021, 00:0655ada0e
/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (C) 2015-2020 Intel Corporation. All rights reserved. */
#ifndef _NDCTL_BITMAP_H_
#define _NDCTL_BITMAP_H_

#include <linux/const.h>
#include <util/size.h>
#include <util/util.h>
#include <ccan/short_types/short_types.h>

#ifndef _UL
#define _UL(x)		(_AC(x, UL))
#endif
#ifndef _ULL
#define _ULL(x)		(_AC(x, ULL))
#endif

#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
#define UL(x)		(_UL(x))
#define ULL(x)		(_ULL(x))

/* GENMASK() and its dependencies copied from include/linux/{bits.h, const.h} */
#define __is_constexpr(x) \
	(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
#define GENMASK_INPUT_CHECK(h, l) \
	(BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
		__is_constexpr((l) > (h)), (l) > (h), 0)))
#define __GENMASK(h, l) \
	(((~UL(0)) - (UL(1) << (l)) + 1) & \
	 (~UL(0) >> (BITS_PER_LONG - 1 - (h))))
#define GENMASK(h, l) \
	(GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))

#define BIT(nr)			(1UL << (nr))
#define BIT_MASK(nr)		(1UL << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr)		((nr) / BITS_PER_LONG)
#define BITS_PER_BYTE		8
#define BITS_TO_LONGS(nr)	DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))

#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
#define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))

#define small_const_nbits(nbits) \
	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)

unsigned long *bitmap_alloc(unsigned long nbits);
void bitmap_set(unsigned long *map, unsigned int start, int len);
void bitmap_clear(unsigned long *map, unsigned int start, int len);
int test_bit(unsigned int nr, const volatile unsigned long *addr);
unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
			    unsigned long offset);
unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
				 unsigned long offset);
int bitmap_full(const unsigned long *src, unsigned int nbits);

/*
 * Bitfield access macros
 * (Copied from Linux's include/linux/bitfield.h)
 *
 * FIELD_{GET,PREP} macros take as first parameter shifted mask
 * from which they extract the base mask and shift amount.
 * Mask must be a compilation time constant.
 *
 * Example:
 *
 *  #define REG_FIELD_A  GENMASK(6, 0)
 *  #define REG_FIELD_B  BIT(7)
 *  #define REG_FIELD_C  GENMASK(15, 8)
 *  #define REG_FIELD_D  GENMASK(31, 16)
 *
 * Get:
 *  a = FIELD_GET(REG_FIELD_A, reg);
 *  b = FIELD_GET(REG_FIELD_B, reg);
 *
 * Set:
 *  reg = FIELD_PREP(REG_FIELD_A, 1) |
 *	  FIELD_PREP(REG_FIELD_B, 0) |
 *	  FIELD_PREP(REG_FIELD_C, c) |
 *	  FIELD_PREP(REG_FIELD_D, 0x40);
 *
 * Modify:
 *  reg &= ~REG_FIELD_C;
 *  reg |= FIELD_PREP(REG_FIELD_C, c);
 */

/* Force a compilation error if a constant expression is not a power of 2 */
#define __BUILD_BUG_ON_NOT_POWER_OF_2(n)	\
	BUILD_BUG_ON(((n) & ((n) - 1)) != 0)
#define BUILD_BUG_ON_NOT_POWER_OF_2(n)			\
	BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))

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

#define __BF_FIELD_CHECK(_mask, _reg, _val)					\
	({									\
		BUILD_BUG_ON(!__builtin_constant_p(_mask));			\
		BUILD_BUG_ON((_mask) == 0);					\
		BUILD_BUG_ON(__builtin_constant_p(_val) ?			\
				 ~((_mask) >> __bf_shf(_mask)) & (_val) : 0);	\
		BUILD_BUG_ON((_mask) > (typeof(_reg))~0ull);			\
		__BUILD_BUG_ON_NOT_POWER_OF_2((_mask) +				\
					      (1ULL << __bf_shf(_mask))); 	\
	})

/**
 * FIELD_GET() - extract a bitfield element
 * @_mask: shifted mask defining the field's length and position
 * @_reg:  value of entire bitfield
 *
 * FIELD_GET() extracts the field specified by @_mask from the
 * bitfield passed in as @_reg by masking and shifting it down.
 */
#define FIELD_GET(_mask, _reg)						\
	({								\
		__BF_FIELD_CHECK(_mask, _reg, 0U);			\
		(typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask));	\
	})

#endif /* _NDCTL_BITMAP_H_ */