From abbc67eedf37a240fe6cdd1ce46eedd12cd3a13f Mon Sep 17 00:00:00 2001 From: Charles Manning Date: Wed, 14 May 2014 14:45:00 +1200 Subject: mkimage : Split out and clean pbl_crc32 for use by other image types The crc32 used by pblimgae is NOT the same as zlib crc32. The pbl_crc32 is useful for other purposes in mkimage so split it out. While we are about it, clean up redundant and confusing code. Signed-off-by: Charles Manning --- tools/pbl_crc32.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 tools/pbl_crc32.c (limited to 'tools/pbl_crc32.c') diff --git a/tools/pbl_crc32.c b/tools/pbl_crc32.c new file mode 100644 index 0000000000..6e6735acde --- /dev/null +++ b/tools/pbl_crc32.c @@ -0,0 +1,56 @@ +/* + * Copyright 2012 Freescale Semiconductor, Inc. + * + * Cleaned up and refactored by Charles Manning. + * + * SPDX-License-Identifier: GPL-2.0+ + */ +#include "pblimage.h" + +static uint32_t crc_table[256]; +static int crc_table_valid; + +static void make_crc_table(void) +{ + uint32_t mask; + int i, j; + uint32_t poly; /* polynomial exclusive-or pattern */ + + if (crc_table_valid) + return; + + /* + * the polynomial used by PBL is 1 + x1 + x2 + x4 + x5 + x7 + x8 + x10 + * + x11 + x12 + x16 + x22 + x23 + x26 + x32. + */ + poly = 0x04c11db7; + + for (i = 0; i < 256; i++) { + mask = i << 24; + for (j = 0; j < 8; j++) { + if (mask & 0x80000000) + mask = (mask << 1) ^ poly; + else + mask <<= 1; + } + crc_table[i] = mask; + } + + crc_table_valid = 1; +} + +uint32_t pbl_crc32(uint32_t in_crc, const char *buf, uint32_t len) +{ + uint32_t crc32_val; + int i; + + make_crc_table(); + + crc32_val = ~in_crc; + + for (i = 0; i < len; i++) + crc32_val = (crc32_val << 8) ^ + crc_table[(crc32_val >> 24) ^ (*buf++ & 0xff)]; + + return crc32_val; +} -- cgit