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