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/array_size.h> 9 #include <linux/bitops.h> 10 #include <linux/build_bug.h> 11 #include <linux/minmax.h> 12 #include <linux/stddef.h> 13 #include <linux/types.h> 14 15 #define QUIRK_MSB_ON_THE_RIGHT BIT(0) 16 #define QUIRK_LITTLE_ENDIAN BIT(1) 17 #define QUIRK_LSW32_IS_FIRST BIT(2) 18 19 enum packing_op { 20 PACK, 21 UNPACK, 22 }; 23 24 /** 25 * packing - Convert numbers (currently u64) between a packed and an unpacked 26 * format. Unpacked means laid out in memory in the CPU's native 27 * understanding of integers, while packed means anything else that 28 * requires translation. 29 * 30 * @pbuf: Pointer to a buffer holding the packed value. 31 * @uval: Pointer to an u64 holding the unpacked value. 32 * @startbit: The index (in logical notation, compensated for quirks) where 33 * the packed value starts within pbuf. Must be larger than, or 34 * equal to, endbit. 35 * @endbit: The index (in logical notation, compensated for quirks) where 36 * the packed value ends within pbuf. Must be smaller than, or equal 37 * to, startbit. 38 * @op: If PACK, then uval will be treated as const pointer and copied (packed) 39 * into pbuf, between startbit and endbit. 40 * If UNPACK, then pbuf will be treated as const pointer and the logical 41 * value between startbit and endbit will be copied (unpacked) to uval. 42 * @quirks: A bit mask of QUIRK_LITTLE_ENDIAN, QUIRK_LSW32_IS_FIRST and 43 * QUIRK_MSB_ON_THE_RIGHT. 44 * 45 * Return: 0 on success, EINVAL or ERANGE if called incorrectly. Assuming 46 * correct usage, return code may be discarded. 47 * If op is PACK, pbuf is modified. 48 * If op is UNPACK, uval is modified. 49 */ 50 int packing(void *pbuf, u64 *uval, int startbit, int endbit, size_t pbuflen, 51 enum packing_op op, u8 quirks); 52 53 #endif 54