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