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Linux kernel mirror (for testing)
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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