projects / mirror_ubuntu-bionic-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 1da177e4 LT |
2 | /* |
| 3 | * There are multiple 16-bit CRC polynomials in common use, but this is | |
| 4 | * *the* standard CRC-32 polynomial, first popularized by Ethernet. | |
| 5 | * x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0 | |
| 6 | */ | |
| 7 | #define CRCPOLY_LE 0xedb88320 | |
| 8 | #define CRCPOLY_BE 0x04c11db7 | |
| 9 | ||
| 46c5801e DW |
10 | /* |
| 11 | * This is the CRC32c polynomial, as outlined by Castagnoli. | |
| 12 | * x^32+x^28+x^27+x^26+x^25+x^23+x^22+x^20+x^19+x^18+x^14+x^13+x^11+x^10+x^9+ | |
| 13 | * x^8+x^6+x^0 | |
| 14 | */ | |
| 15 | #define CRC32C_POLY_LE 0x82F63B78 | |
| 16 | ||
| 5cde7656 DW |
17 | /* Try to choose an implementation variant via Kconfig */ |
| 18 | #ifdef CONFIG_CRC32_SLICEBY8 | |
| 19 | # define CRC_LE_BITS 64 | |
| 20 | # define CRC_BE_BITS 64 | |
| 21 | #endif | |
| 22 | #ifdef CONFIG_CRC32_SLICEBY4 | |
| 23 | # define CRC_LE_BITS 32 | |
| 24 | # define CRC_BE_BITS 32 | |
| 25 | #endif | |
| 26 | #ifdef CONFIG_CRC32_SARWATE | |
| 27 | # define CRC_LE_BITS 8 | |
| 28 | # define CRC_BE_BITS 8 | |
| 29 | #endif | |
| 30 | #ifdef CONFIG_CRC32_BIT | |
| 31 | # define CRC_LE_BITS 1 | |
| 32 | # define CRC_BE_BITS 1 | |
| 33 | #endif | |
| 34 | ||
| 324eb0f1 BP |
35 | /* |
| 36 | * How many bits at a time to use. Valid values are 1, 2, 4, 8, 32 and 64. | |
| 37 | * For less performance-sensitive, use 4 or 8 to save table size. | |
| 38 | * For larger systems choose same as CPU architecture as default. | |
| 39 | * This works well on X86_64, SPARC64 systems. This may require some | |
| 40 | * elaboration after experiments with other architectures. | |
| 41 | */ | |
| e30c7a8f | 42 | #ifndef CRC_LE_BITS |
| 324eb0f1 BP |
43 | # ifdef CONFIG_64BIT |
| 44 | # define CRC_LE_BITS 64 | |
| 45 | # else | |
| 46 | # define CRC_LE_BITS 32 | |
| 47 | # endif | |
| 1da177e4 LT |
48 | #endif |
| 49 | #ifndef CRC_BE_BITS | |
| 324eb0f1 BP |
50 | # ifdef CONFIG_64BIT |
| 51 | # define CRC_BE_BITS 64 | |
| 52 | # else | |
| 53 | # define CRC_BE_BITS 32 | |
| 54 | # endif | |
| 1da177e4 LT |
55 | #endif |
| 56 | ||
| 57 | /* | |
| 58 | * Little-endian CRC computation. Used with serial bit streams sent | |
| 59 | * lsbit-first. Be sure to use cpu_to_le32() to append the computed CRC. | |
| 60 | */ | |
| 324eb0f1 | 61 | #if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \ |
| 9a1dbf6a | 62 | CRC_LE_BITS & CRC_LE_BITS-1 |
| 324eb0f1 | 63 | # error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}" |
| 1da177e4 LT |
64 | #endif |
| 65 | ||
| 66 | /* | |
| 67 | * Big-endian CRC computation. Used with serial bit streams sent | |
| 68 | * msbit-first. Be sure to use cpu_to_be32() to append the computed CRC. | |
| 69 | */ | |
| 324eb0f1 | 70 | #if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \ |
| 9a1dbf6a | 71 | CRC_BE_BITS & CRC_BE_BITS-1 |
| 324eb0f1 | 72 | # error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}" |
| 1da177e4 | 73 | #endif |