1 /* SPDX-License-Identifier: BSD-3-Clause 2 * Copyright (c) 2016-2018, NXP Semiconductors 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
