From cbc0a40e17da361a2ada8d669413ccfbd2028f2d Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 3 Mar 2022 12:13:09 -0800 Subject: lib: add rocksoft model crc64 The NVM Express specification extended data integrity fields to 64 bits using the Rocksoft parameters. Add the poly to the crc64 table generation, and provide a generic library routine implementing the algorithm. The Rocksoft 64-bit CRC model parameters are as follows: Poly: 0xAD93D23594C93659 Initial value: 0xFFFFFFFFFFFFFFFF Reflected Input: True Reflected Output: True Xor Final: 0xFFFFFFFFFFFFFFFF Since this model used reflected bits, the implementation generates the reflected table so the result is ordered consistently. Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Martin K. Petersen Signed-off-by: Keith Busch Reviewed-by: Martin K. Petersen Link: https://lore.kernel.org/r/20220303201312.3255347-6-kbusch@kernel.org Signed-off-by: Jens Axboe --- lib/crc64.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'lib/crc64.c') diff --git a/lib/crc64.c b/lib/crc64.c index 9f852a89ee2a..61ae8dfb6a1c 100644 --- a/lib/crc64.c +++ b/lib/crc64.c @@ -22,6 +22,13 @@ * x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 + * x^7 + x^4 + x + 1 * + * crc64rocksoft[256] table is from the Rocksoft specification polynomial + * defined as, + * + * x^64 + x^63 + x^61 + x^59 + x^58 + x^56 + x^55 + x^52 + x^49 + x^48 + x^47 + + * x^46 + x^44 + x^41 + x^37 + x^36 + x^34 + x^32 + x^31 + x^28 + x^26 + x^23 + + * x^22 + x^19 + x^16 + x^13 + x^12 + x^10 + x^9 + x^6 + x^4 + x^3 + 1 + * * Copyright 2018 SUSE Linux. * Author: Coly Li */ @@ -55,3 +62,24 @@ u64 __pure crc64_be(u64 crc, const void *p, size_t len) return crc; } EXPORT_SYMBOL_GPL(crc64_be); + +/** + * crc64_rocksoft_generic - Calculate bitwise Rocksoft CRC64 + * @crc: seed value for computation. 0 for a new CRC calculation, or the + * previous crc64 value if computing incrementally. + * @p: pointer to buffer over which CRC64 is run + * @len: length of buffer @p + */ +u64 __pure crc64_rocksoft_generic(u64 crc, const void *p, size_t len) +{ + const unsigned char *_p = p; + size_t i; + + crc = ~crc; + + for (i = 0; i < len; i++) + crc = (crc >> 8) ^ crc64rocksofttable[(crc & 0xff) ^ *_p++]; + + return ~crc; +} +EXPORT_SYMBOL_GPL(crc64_rocksoft_generic); -- cgit