[thirdparty/kernel/linux.git] / lib / crc32defs.h

/*
 * 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

/*
 * 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
1da177e4 LT	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
46c5801e DW	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
324eb0f1 BP	16	/*
	17	* How many bits at a time to use. Valid values are 1, 2, 4, 8, 32 and 64.
	18	* For less performance-sensitive, use 4 or 8 to save table size.
	19	* For larger systems choose same as CPU architecture as default.
	20	* This works well on X86_64, SPARC64 systems. This may require some
	21	* elaboration after experiments with other architectures.
	22	*/
e30c7a8f	23	#ifndef CRC_LE_BITS
324eb0f1 BP	24	# ifdef CONFIG_64BIT
	25	# define CRC_LE_BITS 64
	26	# else
	27	# define CRC_LE_BITS 32
	28	# endif
1da177e4 LT	29	#endif
1da177e4 LT	30	#ifndef CRC_BE_BITS
324eb0f1 BP	31	# ifdef CONFIG_64BIT
	32	# define CRC_BE_BITS 64
	33	# else
	34	# define CRC_BE_BITS 32
	35	# endif
1da177e4 LT	36	#endif
	37
	38	/*
	39	* Little-endian CRC computation. Used with serial bit streams sent
	40	* lsbit-first. Be sure to use cpu_to_le32() to append the computed CRC.
	41	*/
324eb0f1	42	#if CRC_LE_BITS > 64 \|\| CRC_LE_BITS < 1 \|\| CRC_LE_BITS == 16 \|\| \
9a1dbf6a	43	CRC_LE_BITS & CRC_LE_BITS-1
324eb0f1	44	# error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}"
1da177e4 LT	45	#endif
	46
	47	/*
	48	* Big-endian CRC computation. Used with serial bit streams sent
	49	* msbit-first. Be sure to use cpu_to_be32() to append the computed CRC.
	50	*/
324eb0f1	51	#if CRC_BE_BITS > 64 \|\| CRC_BE_BITS < 1 \|\| CRC_BE_BITS == 16 \|\| \
9a1dbf6a	52	CRC_BE_BITS & CRC_BE_BITS-1
324eb0f1	53	# error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}"
1da177e4	54	#endif