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 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 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