xref: /openbmc/u-boot/tools/pbl_crc32.c (revision e8f80a5a)
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 
9 static uint32_t crc_table[256];
10 static int crc_table_valid;
11 
make_crc_table(void)12 static 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 
pbl_crc32(uint32_t in_crc,const char * buf,uint32_t len)41 uint32_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