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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * crc7.c4 */5 6#include <linux/types.h>7#include <linux/module.h>8#include <linux/crc7.h>9 10 11/*12 * Table for CRC-7 (polynomial x^7 + x^3 + 1).13 * This is a big-endian CRC (msbit is highest power of x),14 * aligned so the msbit of the byte is the x^6 coefficient15 * and the lsbit is not used.16 */17const u8 crc7_be_syndrome_table[256] = {18 0x00, 0x12, 0x24, 0x36, 0x48, 0x5a, 0x6c, 0x7e,19 0x90, 0x82, 0xb4, 0xa6, 0xd8, 0xca, 0xfc, 0xee,20 0x32, 0x20, 0x16, 0x04, 0x7a, 0x68, 0x5e, 0x4c,21 0xa2, 0xb0, 0x86, 0x94, 0xea, 0xf8, 0xce, 0xdc,22 0x64, 0x76, 0x40, 0x52, 0x2c, 0x3e, 0x08, 0x1a,23 0xf4, 0xe6, 0xd0, 0xc2, 0xbc, 0xae, 0x98, 0x8a,24 0x56, 0x44, 0x72, 0x60, 0x1e, 0x0c, 0x3a, 0x28,25 0xc6, 0xd4, 0xe2, 0xf0, 0x8e, 0x9c, 0xaa, 0xb8,26 0xc8, 0xda, 0xec, 0xfe, 0x80, 0x92, 0xa4, 0xb6,27 0x58, 0x4a, 0x7c, 0x6e, 0x10, 0x02, 0x34, 0x26,28 0xfa, 0xe8, 0xde, 0xcc, 0xb2, 0xa0, 0x96, 0x84,29 0x6a, 0x78, 0x4e, 0x5c, 0x22, 0x30, 0x06, 0x14,30 0xac, 0xbe, 0x88, 0x9a, 0xe4, 0xf6, 0xc0, 0xd2,31 0x3c, 0x2e, 0x18, 0x0a, 0x74, 0x66, 0x50, 0x42,32 0x9e, 0x8c, 0xba, 0xa8, 0xd6, 0xc4, 0xf2, 0xe0,33 0x0e, 0x1c, 0x2a, 0x38, 0x46, 0x54, 0x62, 0x70,34 0x82, 0x90, 0xa6, 0xb4, 0xca, 0xd8, 0xee, 0xfc,35 0x12, 0x00, 0x36, 0x24, 0x5a, 0x48, 0x7e, 0x6c,36 0xb0, 0xa2, 0x94, 0x86, 0xf8, 0xea, 0xdc, 0xce,37 0x20, 0x32, 0x04, 0x16, 0x68, 0x7a, 0x4c, 0x5e,38 0xe6, 0xf4, 0xc2, 0xd0, 0xae, 0xbc, 0x8a, 0x98,39 0x76, 0x64, 0x52, 0x40, 0x3e, 0x2c, 0x1a, 0x08,40 0xd4, 0xc6, 0xf0, 0xe2, 0x9c, 0x8e, 0xb8, 0xaa,41 0x44, 0x56, 0x60, 0x72, 0x0c, 0x1e, 0x28, 0x3a,42 0x4a, 0x58, 0x6e, 0x7c, 0x02, 0x10, 0x26, 0x34,43 0xda, 0xc8, 0xfe, 0xec, 0x92, 0x80, 0xb6, 0xa4,44 0x78, 0x6a, 0x5c, 0x4e, 0x30, 0x22, 0x14, 0x06,45 0xe8, 0xfa, 0xcc, 0xde, 0xa0, 0xb2, 0x84, 0x96,46 0x2e, 0x3c, 0x0a, 0x18, 0x66, 0x74, 0x42, 0x50,47 0xbe, 0xac, 0x9a, 0x88, 0xf6, 0xe4, 0xd2, 0xc0,48 0x1c, 0x0e, 0x38, 0x2a, 0x54, 0x46, 0x70, 0x62,49 0x8c, 0x9e, 0xa8, 0xba, 0xc4, 0xd6, 0xe0, 0xf250};51EXPORT_SYMBOL(crc7_be_syndrome_table);52 53/**54 * crc7_be - update the CRC7 for the data buffer55 * @crc: previous CRC7 value56 * @buffer: data pointer57 * @len: number of bytes in the buffer58 * Context: any59 *60 * Returns the updated CRC7 value.61 * The CRC7 is left-aligned in the byte (the lsbit is always 0), as that62 * makes the computation easier, and all callers want it in that form.63 *64 */65u8 crc7_be(u8 crc, const u8 *buffer, size_t len)66{67 while (len--)68 crc = crc7_be_byte(crc, *buffer++);69 return crc;70}71EXPORT_SYMBOL(crc7_be);72 73MODULE_DESCRIPTION("CRC7 calculations");74MODULE_LICENSE("GPL");75