LXR uboot/tools/pbl

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Copyright 2012 Freescale Semiconductor, Inc.
   4 *
   5 * Cleaned up and refactored by Charles Manning.
   6 */
   7#include "pblimage.h"
   8
   9static uint32_t crc_table[256];
  10static int crc_table_valid;
  11
  12static void make_crc_table(void)
  13{
  14        uint32_t mask;
  15        int i, j;
  16        uint32_t poly; /* polynomial exclusive-or pattern */
  17
  18        if (crc_table_valid)
  19                return;
  20
  21        /*
  22         * the polynomial used by PBL is 1 + x1 + x2 + x4 + x5 + x7 + x8 + x10
  23         * + x11 + x12 + x16 + x22 + x23 + x26 + x32.
  24         */
  25        poly = 0x04c11db7;
  26
  27        for (i = 0; i < 256; i++) {
  28                mask = i << 24;
  29                for (j = 0; j < 8; j++) {
  30                        if (mask & 0x80000000)
  31                                mask = (mask << 1) ^ poly;
  32                        else
  33                                mask <<= 1;
  34                }
  35                crc_table[i] = mask;
  36        }
  37
  38        crc_table_valid = 1;
  39}
  40
  41uint32_t pbl_crc32(uint32_t in_crc, const char *buf, uint32_t len)
  42{
  43        uint32_t crc32_val;
  44        int i;
  45
  46        make_crc_table();
  47
  48        crc32_val = ~in_crc;
  49
  50        for (i = 0; i < len; i++)
  51                crc32_val = (crc32_val << 8) ^
  52                        crc_table[(crc32_val >> 24) ^ (*buf++ & 0xff)];
  53
  54        return crc32_val;
  55}
  56