xref: /openbmc/u-boot/tools/pbl_crc32.c (revision d330e04d9d427a26381b59f40875af17f4c288a2)
1  /*
2   * Copyright 2012 Freescale Semiconductor, Inc.
3   *
4   * Cleaned up and refactored by Charles Manning.
5   *
6   * SPDX-License-Identifier:	GPL-2.0+
7   */
8  #include "pblimage.h"
9  
10  static uint32_t crc_table[256];
11  static int crc_table_valid;
12  
13  static 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  
42  uint32_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