--- lib/crc32defs.h

+++ lib/crc32defs.h

@@ -6,27 +6,67 @@

#define CRCPOLY_LE 0xedb88320

#define CRCPOLY_BE 0x04c11db7

-/* How many bits at a time to use. Requires a table of 4<<CRC_xx_BITS bytes. */

-/* For less performance-sensitive, use 4 */

-#ifndef CRC_LE_BITS

+/*

+ * 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

-# define CRC_BE_BITS 8

+# 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 > 8 || CRC_LE_BITS < 1 || CRC_LE_BITS & CRC_LE_BITS-1

-# error CRC_LE_BITS must be a power of 2 between 1 and 8

+#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 > 8 || CRC_BE_BITS < 1 || CRC_BE_BITS & CRC_BE_BITS-1

-# error CRC_BE_BITS must be a power of 2 between 1 and 8

+#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