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554aae35 | 1 | /* SPDX-License-Identifier: BSD-3-Clause |
3c9cfb52 | 2 | * Copyright 2016-2018 NXP |
554aae35 VO |
3 | * Copyright (c) 2018-2019, Vladimir Oltean <olteanv@gmail.com> |
4 | */ | |
5 | #ifndef _LINUX_PACKING_H | |
6 | #define _LINUX_PACKING_H | |
7 | ||
8 | #include <linux/types.h> | |
9 | #include <linux/bitops.h> | |
10 | ||
11 | #define QUIRK_MSB_ON_THE_RIGHT BIT(0) | |
12 | #define QUIRK_LITTLE_ENDIAN BIT(1) | |
13 | #define QUIRK_LSW32_IS_FIRST BIT(2) | |
14 | ||
15 | enum packing_op { | |
16 | PACK, | |
17 | UNPACK, | |
18 | }; | |
19 | ||
20 | /** | |
21 | * packing - Convert numbers (currently u64) between a packed and an unpacked | |
22 | * format. Unpacked means laid out in memory in the CPU's native | |
23 | * understanding of integers, while packed means anything else that | |
24 | * requires translation. | |
25 | * | |
26 | * @pbuf: Pointer to a buffer holding the packed value. | |
27 | * @uval: Pointer to an u64 holding the unpacked value. | |
28 | * @startbit: The index (in logical notation, compensated for quirks) where | |
29 | * the packed value starts within pbuf. Must be larger than, or | |
30 | * equal to, endbit. | |
31 | * @endbit: The index (in logical notation, compensated for quirks) where | |
32 | * the packed value ends within pbuf. Must be smaller than, or equal | |
33 | * to, startbit. | |
34 | * @op: If PACK, then uval will be treated as const pointer and copied (packed) | |
35 | * into pbuf, between startbit and endbit. | |
36 | * If UNPACK, then pbuf will be treated as const pointer and the logical | |
37 | * value between startbit and endbit will be copied (unpacked) to uval. | |
38 | * @quirks: A bit mask of QUIRK_LITTLE_ENDIAN, QUIRK_LSW32_IS_FIRST and | |
39 | * QUIRK_MSB_ON_THE_RIGHT. | |
40 | * | |
41 | * Return: 0 on success, EINVAL or ERANGE if called incorrectly. Assuming | |
42 | * correct usage, return code may be discarded. | |
43 | * If op is PACK, pbuf is modified. | |
44 | * If op is UNPACK, uval is modified. | |
45 | */ | |
46 | int packing(void *pbuf, u64 *uval, int startbit, int endbit, size_t pbuflen, | |
47 | enum packing_op op, u8 quirks); | |
48 | ||
49 | #endif |