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#include <u-boot/crc.h>
   9
  10static uint32_t crc_table[256];
  11static int crc_table_valid;
  12
  13static void make_crc_table(void)
  14{
  15        uint32_t mask;
  16        int i, j;
  17        uint32_t poly; /* polynomial exclusive-or pattern */
  18
  19        if (crc_table_valid)
  20                return;
  21
  22        /*
  23         * the polynomial used by PBL is 1 + x1 + x2 + x4 + x5 + x7 + x8 + x10
  24         * + x11 + x12 + x16 + x22 + x23 + x26 + x32.
  25         */
  26        poly = 0x04c11db7;
  27
  28        for (i = 0; i < 256; i++) {
  29                mask = i << 24;
  30                for (j = 0; j < 8; j++) {
  31                        if (mask & 0x80000000)
  32                                mask = (mask << 1) ^ poly;
  33                        else
  34                                mask <<= 1;
  35                }
  36                crc_table[i] = mask;
  37        }
  38
  39        crc_table_valid = 1;
  40}
  41
  42uint32_t pbl_crc32(uint32_t in_crc, const char *buf, uint32_t len)
  43{
  44        uint32_t crc32_val;
  45        int i;
  46
  47        make_crc_table();
  48
  49        crc32_val = ~in_crc;
  50
  51        for (i = 0; i < len; i++)
  52                crc32_val = (crc32_val << 8) ^
  53                        crc_table[(crc32_val >> 24) ^ (*buf++ & 0xff)];
  54
  55        return crc32_val;
  56}
  57