lib/crc8.c

   1 /*
   2  * Copyright (c) 2013 Google, Inc
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include "linux/crc8.h"
   8
   9 #define POLY    (0x1070U << 3)
  10
  11 static unsigned char _crc8(unsigned short data)
  12 {
  13         int i;
  14
  15         for (i = 0; i < 8; i++) {
  16                 if (data & 0x8000)
  17                         data = data ^ POLY;
  18                 data = data << 1;
  19         }
  20
  21         return (unsigned char)(data >> 8);
  22 }
  23
  24 unsigned int crc8(unsigned int crc, const unsigned char *vptr, int len)
  25 {
  26         int i;
  27
  28         for (i = 0; i < len; i++)
  29                 crc = _crc8((crc ^ vptr[i]) << 8);
  30
  31         return crc;
  32 }