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