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 
10 static uint32_t crc_table[256];
11 static int crc_table_valid;
12 
make_crc_table(void)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 
pbl_crc32(uint32_t in_crc,const char * buf,uint32_t len)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