lib/crc8.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (c) 2013 Google, Inc
   4  */
   5
   6 #ifdef USE_HOSTCC
   7 #include <arpa/inet.h>
   8 #endif
   9 #include <u-boot/crc.h>
  10
  11 #define POLY    (0x1070U << 3)
  12
  13 static unsigned char _crc8(unsigned short data)
  14 {
  15         int i;
  16
  17         for (i = 0; i < 8; i++) {
  18                 if (data & 0x8000)
  19                         data = data ^ POLY;
  20                 data = data << 1;
  21         }
  22
  23         return (unsigned char)(data >> 8);
  24 }
  25
  26 unsigned int crc8(unsigned int crc, const unsigned char *vptr, int len)
  27 {
  28         int i;
  29
  30         for (i = 0; i < len; i++)
  31                 crc = _crc8((crc ^ vptr[i]) << 8);
  32
  33         return crc;
  34 }