projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 40b0b3f8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
| ad241528 JN |
2 | /* |
| 3 | * crc7.c | |
| ad241528 JN |
4 | */ |
| 5 | ||
| 6 | #include <linux/types.h> | |
| 7 | #include <linux/module.h> | |
| 8 | #include <linux/crc7.h> | |
| 9 | ||
| 10 | ||
| 1836eea2 GS |
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 coefficient | |
| 15 | * and the lsbit is not used. | |
| 16 | */ | |
| 17 | const 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, 0xf2 | |
| ad241528 | 50 | }; |
| 1836eea2 | 51 | EXPORT_SYMBOL(crc7_be_syndrome_table); |
| ad241528 JN |
52 | |
| 53 | /** | |
| 8276d3b4 | 54 | * crc7_be - update the CRC7 for the data buffer |
| ad241528 JN |
55 | * @crc: previous CRC7 value |
| 56 | * @buffer: data pointer | |
| 57 | * @len: number of bytes in the buffer | |
| 58 | * Context: any | |
| 59 | * | |
| 60 | * Returns the updated CRC7 value. | |
| 1836eea2 GS |
61 | * The CRC7 is left-aligned in the byte (the lsbit is always 0), as that |
| 62 | * makes the computation easier, and all callers want it in that form. | |
| 63 | * | |
| ad241528 | 64 | */ |
| 1836eea2 | 65 | u8 crc7_be(u8 crc, const u8 *buffer, size_t len) |
| ad241528 JN |
66 | { |
| 67 | while (len--) | |
| 1836eea2 | 68 | crc = crc7_be_byte(crc, *buffer++); |
| ad241528 JN |
69 | return crc; |
| 70 | } | |
| 1836eea2 | 71 | EXPORT_SYMBOL(crc7_be); |
| ad241528 JN |
72 | |
| 73 | MODULE_DESCRIPTION("CRC7 calculations"); | |
| 74 | MODULE_LICENSE("GPL"); |