diff options
| -rw-r--r-- | include/linux/crc-itu-t.h | 28 | ||||
| -rw-r--r-- | lib/Kconfig | 8 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/crc-itu-t.c | 69 |
4 files changed, 106 insertions, 0 deletions
diff --git a/include/linux/crc-itu-t.h b/include/linux/crc-itu-t.h new file mode 100644 index 0000000..84920f3 --- /dev/null +++ b/include/linux/crc-itu-t.h @@ -0,0 +1,28 @@ +/* + * crc-itu-t.h - CRC ITU-T V.41 routine + * + * Implements the standard CRC ITU-T V.41: + * Width 16 + * Poly 0x0x1021 (x^16 + x^12 + x^15 + 1) + * Init 0 + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + +#ifndef CRC_ITU_T_H +#define CRC_ITU_T_H + +#include <linux/types.h> + +extern u16 const crc_itu_t_table[256]; + +extern u16 crc_itu_t(u16 crc, const u8 *buffer, size_t len); + +static inline u16 crc_itu_t_byte(u16 crc, const u8 data) +{ + return (crc << 8) ^ crc_itu_t_table[((crc >> 8) ^ data) & 0xff]; +} + +#endif /* CRC_ITU_T_H */ + diff --git a/lib/Kconfig b/lib/Kconfig index 3842499..91477b9 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -23,6 +23,14 @@ config CRC16 the kernel tree does. Such modules that use library CRC16 functions require M here. +config CRC_ITU_T + tristate "CRC ITU-T V.41 functions" + help + This option is provided for the case where no in-kernel-tree + modules require CRC ITU-T V.41 functions, but a module built outside + the kernel tree does. Such modules that use library CRC ITU-T V.41 + functions require M here. + config CRC32 tristate "CRC32 functions" default y diff --git a/lib/Makefile b/lib/Makefile index 992a39e..2a9e47c 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -40,6 +40,7 @@ endif obj-$(CONFIG_BITREVERSE) += bitrev.o obj-$(CONFIG_CRC_CCITT) += crc-ccitt.o obj-$(CONFIG_CRC16) += crc16.o +obj-$(CONFIG_CRC_ITU_T) += crc-itu-t.o obj-$(CONFIG_CRC32) += crc32.o obj-$(CONFIG_LIBCRC32C) += libcrc32c.o obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o diff --git a/lib/crc-itu-t.c b/lib/crc-itu-t.c new file mode 100644 index 0000000..a63472b --- /dev/null +++ b/lib/crc-itu-t.c @@ -0,0 +1,69 @@ +/* + * crc-itu-t.c + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + +#include <linux/types.h> +#include <linux/module.h> +#include <linux/crc-itu-t.h> + +/** CRC table for the CRC ITU-T V.41 0x0x1021 (x^16 + x^12 + x^15 + 1) */ +const u16 crc_itu_t_table[256] = { + 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, + 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, + 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, + 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, + 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, + 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, + 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, + 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, + 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, + 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, + 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, + 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, + 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, + 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, + 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, + 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, + 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, + 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, + 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, + 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, + 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, + 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, + 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, + 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, + 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, + 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, + 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, + 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, + 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, + 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, + 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, + 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0 +}; + +EXPORT_SYMBOL(crc_itu_t_table); + +/** + * crc_itu_t - Compute the CRC-ITU-T for the data buffer + * + * @crc: previous CRC value + * @buffer: data pointer + * @len: number of bytes in the buffer + * + * Returns the updated CRC value + */ +u16 crc_itu_t(u16 crc, const u8 *buffer, size_t len) +{ + while (len--) + crc = crc_itu_t_byte(crc, *buffer++); + return crc; +} +EXPORT_SYMBOL(crc_itu_t); + +MODULE_DESCRIPTION("CRC ITU-T V.41 calculations"); +MODULE_LICENSE("GPL"); + |