abbc67eedf
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 <cdhmanning@gmail.com>
57 lines
1017 B
C
57 lines
1017 B
C
/*
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* Copyright 2012 Freescale Semiconductor, Inc.
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*
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* Cleaned up and refactored by Charles Manning.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include "pblimage.h"
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static uint32_t crc_table[256];
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static int crc_table_valid;
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static void make_crc_table(void)
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{
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uint32_t mask;
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int i, j;
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uint32_t poly; /* polynomial exclusive-or pattern */
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if (crc_table_valid)
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return;
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/*
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* the polynomial used by PBL is 1 + x1 + x2 + x4 + x5 + x7 + x8 + x10
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* + x11 + x12 + x16 + x22 + x23 + x26 + x32.
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*/
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poly = 0x04c11db7;
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for (i = 0; i < 256; i++) {
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mask = i << 24;
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for (j = 0; j < 8; j++) {
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if (mask & 0x80000000)
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mask = (mask << 1) ^ poly;
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else
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mask <<= 1;
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}
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crc_table[i] = mask;
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}
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crc_table_valid = 1;
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}
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uint32_t pbl_crc32(uint32_t in_crc, const char *buf, uint32_t len)
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{
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uint32_t crc32_val;
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int i;
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make_crc_table();
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crc32_val = ~in_crc;
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for (i = 0; i < len; i++)
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crc32_val = (crc32_val << 8) ^
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crc_table[(crc32_val >> 24) ^ (*buf++ & 0xff)];
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return crc32_val;
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}
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