/*
   * Copyright 2012 Freescale Semiconductor, Inc.
   *
   * Cleaned up and refactored by Charles Manning.
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  #include "pblimage.h"
  
  static uint32_t crc_table[256];
  static int crc_table_valid;
  
  static void make_crc_table(void)
  {
  	uint32_t mask;
  	int i, j;
  	uint32_t poly; /* polynomial exclusive-or pattern */
  
  	if (crc_table_valid)
  		return;
  
  	/*
  	 * the polynomial used by PBL is 1 + x1 + x2 + x4 + x5 + x7 + x8 + x10
  	 * + x11 + x12 + x16 + x22 + x23 + x26 + x32.
  	 */
  	poly = 0x04c11db7;
  
  	for (i = 0; i < 256; i++) {
  		mask = i << 24;
  		for (j = 0; j < 8; j++) {
  			if (mask & 0x80000000)
  				mask = (mask << 1) ^ poly;
  			else
  				mask <<= 1;
  		}
  		crc_table[i] = mask;
  	}
  
  	crc_table_valid = 1;
  }
  
  uint32_t pbl_crc32(uint32_t in_crc, const char *buf, uint32_t len)
  {
  	uint32_t crc32_val;
  	int i;
  
  	make_crc_table();
  
  	crc32_val = ~in_crc;
  
  	for (i = 0; i < len; i++)
  		crc32_val = (crc32_val << 8) ^
  			crc_table[(crc32_val >> 24) ^ (*buf++ & 0xff)];
  
  	return crc32_val;
  }