[linux.git] / lib / crc32defs.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * There are multiple 16-bit CRC polynomials in common use, but this is
 * *the* standard CRC-32 polynomial, first popularized by Ethernet.
 * 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
 */
#define CRCPOLY_LE 0xedb88320
#define CRCPOLY_BE 0x04c11db7

/*
 * This is the CRC32c polynomial, as outlined by Castagnoli.
 * 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+
 * x^8+x^6+x^0
 */
#define CRC32C_POLY_LE 0x82F63B78

/* Try to choose an implementation variant via Kconfig */
#ifdef CONFIG_CRC32_SLICEBY8
# define CRC_LE_BITS 64
# define CRC_BE_BITS 64
#endif
#ifdef CONFIG_CRC32_SLICEBY4
# define CRC_LE_BITS 32
# define CRC_BE_BITS 32
#endif
#ifdef CONFIG_CRC32_SARWATE
# define CRC_LE_BITS 8
# define CRC_BE_BITS 8
#endif
#ifdef CONFIG_CRC32_BIT
# define CRC_LE_BITS 1
# define CRC_BE_BITS 1
#endif

/*
 * How many bits at a time to use.  Valid values are 1, 2, 4, 8, 32 and 64.
 * For less performance-sensitive, use 4 or 8 to save table size.
 * For larger systems choose same as CPU architecture as default.
 * This works well on X86_64, SPARC64 systems. This may require some
 * elaboration after experiments with other architectures.
 */
#ifndef CRC_LE_BITS
#  ifdef CONFIG_64BIT
#  define CRC_LE_BITS 64
#  else
#  define CRC_LE_BITS 32
#  endif
#endif
#ifndef CRC_BE_BITS
#  ifdef CONFIG_64BIT
#  define CRC_BE_BITS 64
#  else
#  define CRC_BE_BITS 32
#  endif
#endif

/*
 * Little-endian CRC computation.  Used with serial bit streams sent
 * lsbit-first.  Be sure to use cpu_to_le32() to append the computed CRC.
 */
#if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \
	CRC_LE_BITS & CRC_LE_BITS-1
# error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}"
#endif

/*
 * Big-endian CRC computation.  Used with serial bit streams sent
 * msbit-first.  Be sure to use cpu_to_be32() to append the computed CRC.
 */
#if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \
	CRC_BE_BITS & CRC_BE_BITS-1
# error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}"
#endif
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	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
46c5801e DW	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
5cde7656 DW	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
324eb0f1 BP	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	*/
e30c7a8f	42	#ifndef CRC_LE_BITS
324eb0f1 BP	43	# ifdef CONFIG_64BIT
	44	# define CRC_LE_BITS 64
	45	# else
	46	# define CRC_LE_BITS 32
	47	# endif
1da177e4 LT	48	#endif
1da177e4 LT	49	#ifndef CRC_BE_BITS
324eb0f1 BP	50	# ifdef CONFIG_64BIT
	51	# define CRC_BE_BITS 64
	52	# else
	53	# define CRC_BE_BITS 32
	54	# endif
1da177e4 LT	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	*/
324eb0f1	61	#if CRC_LE_BITS > 64 \|\| CRC_LE_BITS < 1 \|\| CRC_LE_BITS == 16 \|\| \
9a1dbf6a	62	CRC_LE_BITS & CRC_LE_BITS-1
324eb0f1	63	# error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}"
1da177e4 LT	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	*/
324eb0f1	70	#if CRC_BE_BITS > 64 \|\| CRC_BE_BITS < 1 \|\| CRC_BE_BITS == 16 \|\| \
9a1dbf6a	71	CRC_BE_BITS & CRC_BE_BITS-1
324eb0f1	72	# error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}"
1da177e4	73	#endif