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/*

 *      crc7.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/crc7.h>

/* Table for CRC-7 (polynomial x^7 + x^3 + 1) */

const u8 crc7_syndrome_table[256] = {

        0x00, 0x09, 0x12, 0x1b, 0x24, 0x2d, 0x36, 0x3f,

        0x48, 0x41, 0x5a, 0x53, 0x6c, 0x65, 0x7e, 0x77,

        0x19, 0x10, 0x0b, 0x02, 0x3d, 0x34, 0x2f, 0x26,

        0x51, 0x58, 0x43, 0x4a, 0x75, 0x7c, 0x67, 0x6e,

        0x32, 0x3b, 0x20, 0x29, 0x16, 0x1f, 0x04, 0x0d,

        0x7a, 0x73, 0x68, 0x61, 0x5e, 0x57, 0x4c, 0x45,

        0x2b, 0x22, 0x39, 0x30, 0x0f, 0x06, 0x1d, 0x14,

        0x63, 0x6a, 0x71, 0x78, 0x47, 0x4e, 0x55, 0x5c,

        0x64, 0x6d, 0x76, 0x7f, 0x40, 0x49, 0x52, 0x5b,

        0x2c, 0x25, 0x3e, 0x37, 0x08, 0x01, 0x1a, 0x13,

        0x7d, 0x74, 0x6f, 0x66, 0x59, 0x50, 0x4b, 0x42,

        0x35, 0x3c, 0x27, 0x2e, 0x11, 0x18, 0x03, 0x0a,

        0x56, 0x5f, 0x44, 0x4d, 0x72, 0x7b, 0x60, 0x69,

        0x1e, 0x17, 0x0c, 0x05, 0x3a, 0x33, 0x28, 0x21,

        0x4f, 0x46, 0x5d, 0x54, 0x6b, 0x62, 0x79, 0x70,

        0x07, 0x0e, 0x15, 0x1c, 0x23, 0x2a, 0x31, 0x38,

        0x41, 0x48, 0x53, 0x5a, 0x65, 0x6c, 0x77, 0x7e,

        0x09, 0x00, 0x1b, 0x12, 0x2d, 0x24, 0x3f, 0x36,

        0x58, 0x51, 0x4a, 0x43, 0x7c, 0x75, 0x6e, 0x67,

        0x10, 0x19, 0x02, 0x0b, 0x34, 0x3d, 0x26, 0x2f,

        0x73, 0x7a, 0x61, 0x68, 0x57, 0x5e, 0x45, 0x4c,

        0x3b, 0x32, 0x29, 0x20, 0x1f, 0x16, 0x0d, 0x04,

        0x6a, 0x63, 0x78, 0x71, 0x4e, 0x47, 0x5c, 0x55,

        0x22, 0x2b, 0x30, 0x39, 0x06, 0x0f, 0x14, 0x1d,

        0x25, 0x2c, 0x37, 0x3e, 0x01, 0x08, 0x13, 0x1a,

        0x6d, 0x64, 0x7f, 0x76, 0x49, 0x40, 0x5b, 0x52,

        0x3c, 0x35, 0x2e, 0x27, 0x18, 0x11, 0x0a, 0x03,

        0x74, 0x7d, 0x66, 0x6f, 0x50, 0x59, 0x42, 0x4b,

        0x17, 0x1e, 0x05, 0x0c, 0x33, 0x3a, 0x21, 0x28,

        0x5f, 0x56, 0x4d, 0x44, 0x7b, 0x72, 0x69, 0x60,

        0x0e, 0x07, 0x1c, 0x15, 0x2a, 0x23, 0x38, 0x31,

        0x46, 0x4f, 0x54, 0x5d, 0x62, 0x6b, 0x70, 0x79

};

EXPORT_SYMBOL(crc7_syndrome_table);

/**

 * crc7 - update the CRC7 for the data buffer

 * @crc:     previous CRC7 value

 * @buffer:  data pointer

 * @len:     number of bytes in the buffer

 * Context: any

 *

 * Returns the updated CRC7 value.

 */

u8 crc7(u8 crc, const u8 *buffer, size_t len)

{

        while (len--)

                crc = crc7_byte(crc, *buffer++);

        return crc;

}

EXPORT_SYMBOL(crc7);

MODULE_DESCRIPTION("CRC7 calculations");

MODULE_LICENSE("GPL");