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