1 /* SPDX-License-Identifier: GPL-2.0 */ 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 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 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 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 */ 42 #ifndef CRC_LE_BITS 43 # ifdef CONFIG_64BIT 44 # define CRC_LE_BITS 64 45 # else 46 # define CRC_LE_BITS 32 47 # endif 48 #endif 49 #ifndef CRC_BE_BITS 50 # ifdef CONFIG_64BIT 51 # define CRC_BE_BITS 64 52 # else 53 # define CRC_BE_BITS 32 54 # endif 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 */ 61 #if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \ 62 CRC_LE_BITS & CRC_LE_BITS-1 63 # error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}" 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 */ 70 #if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \ 71 CRC_BE_BITS & CRC_BE_BITS-1 72 # error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}" 73 #endif 74