Current File : //usr/src/linux-headers-5.15.0-125-generic/include/linux/packing.h
/* SPDX-License-Identifier: BSD-3-Clause
* Copyright 2016-2018 NXP
* Copyright (c) 2018-2019, Vladimir Oltean <olteanv@gmail.com>
*/
#ifndef _LINUX_PACKING_H
#define _LINUX_PACKING_H
#include <linux/types.h>
#include <linux/bitops.h>
#define QUIRK_MSB_ON_THE_RIGHT BIT(0)
#define QUIRK_LITTLE_ENDIAN BIT(1)
#define QUIRK_LSW32_IS_FIRST BIT(2)
enum packing_op {
PACK,
UNPACK,
};
/**
* packing - Convert numbers (currently u64) between a packed and an unpacked
* format. Unpacked means laid out in memory in the CPU's native
* understanding of integers, while packed means anything else that
* requires translation.
*
* @pbuf: Pointer to a buffer holding the packed value.
* @uval: Pointer to an u64 holding the unpacked value.
* @startbit: The index (in logical notation, compensated for quirks) where
* the packed value starts within pbuf. Must be larger than, or
* equal to, endbit.
* @endbit: The index (in logical notation, compensated for quirks) where
* the packed value ends within pbuf. Must be smaller than, or equal
* to, startbit.
* @op: If PACK, then uval will be treated as const pointer and copied (packed)
* into pbuf, between startbit and endbit.
* If UNPACK, then pbuf will be treated as const pointer and the logical
* value between startbit and endbit will be copied (unpacked) to uval.
* @quirks: A bit mask of QUIRK_LITTLE_ENDIAN, QUIRK_LSW32_IS_FIRST and
* QUIRK_MSB_ON_THE_RIGHT.
*
* Return: 0 on success, EINVAL or ERANGE if called incorrectly. Assuming
* correct usage, return code may be discarded.
* If op is PACK, pbuf is modified.
* If op is UNPACK, uval is modified.
*/
int packing(void *pbuf, u64 *uval, int startbit, int endbit, size_t pbuflen,
enum packing_op op, u8 quirks);
#endif
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