1 | /* SPDX-License-Identifier: BSD-3-Clause |
2 | * Copyright 2016-2018 NXP |
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 |
50 | |