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72 lines
2.0 KiB
72 lines
2.0 KiB
/* |
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* There are multiple 16-bit CRC polynomials in common use, but this is |
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* *the* standard CRC-32 polynomial, first popularized by Ethernet. |
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* 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 |
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*/ |
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#define CRCPOLY_LE 0xedb88320 |
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#define CRCPOLY_BE 0x04c11db7 |
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/* |
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* This is the CRC32c polynomial, as outlined by Castagnoli. |
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* 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+ |
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* x^8+x^6+x^0 |
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*/ |
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#define CRC32C_POLY_LE 0x82F63B78 |
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/* Try to choose an implementation variant via Kconfig */ |
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#ifdef CONFIG_CRC32_SLICEBY8 |
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# define CRC_LE_BITS 64 |
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# define CRC_BE_BITS 64 |
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#endif |
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#ifdef CONFIG_CRC32_SLICEBY4 |
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# define CRC_LE_BITS 32 |
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# define CRC_BE_BITS 32 |
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#endif |
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#ifdef CONFIG_CRC32_SARWATE |
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# define CRC_LE_BITS 8 |
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# define CRC_BE_BITS 8 |
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#endif |
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#ifdef CONFIG_CRC32_BIT |
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# define CRC_LE_BITS 1 |
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# define CRC_BE_BITS 1 |
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#endif |
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/* |
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* How many bits at a time to use. Valid values are 1, 2, 4, 8, 32 and 64. |
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* For less performance-sensitive, use 4 or 8 to save table size. |
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* For larger systems choose same as CPU architecture as default. |
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* This works well on X86_64, SPARC64 systems. This may require some |
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* elaboration after experiments with other architectures. |
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*/ |
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#ifndef CRC_LE_BITS |
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# ifdef CONFIG_64BIT |
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# define CRC_LE_BITS 64 |
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# else |
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# define CRC_LE_BITS 32 |
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# endif |
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#endif |
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#ifndef CRC_BE_BITS |
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# ifdef CONFIG_64BIT |
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# define CRC_BE_BITS 64 |
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# else |
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# define CRC_BE_BITS 32 |
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# endif |
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#endif |
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/* |
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* Little-endian CRC computation. Used with serial bit streams sent |
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* lsbit-first. Be sure to use cpu_to_le32() to append the computed CRC. |
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*/ |
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#if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \ |
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CRC_LE_BITS & CRC_LE_BITS-1 |
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# error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}" |
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#endif |
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/* |
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* Big-endian CRC computation. Used with serial bit streams sent |
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* msbit-first. Be sure to use cpu_to_be32() to append the computed CRC. |
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*/ |
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#if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \ |
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CRC_BE_BITS & CRC_BE_BITS-1 |
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# error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}" |
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#endif
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