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lib: add calculate crc byte by byte 

Change-Id: I5cab1f90452b08a464ad7a2d7e75d97187452992
Signed-off-by: Xiang Wang <merle@hardenedlinux.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36624
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
This commit is contained in:
Xiang Wang 2019-11-05 12:00:39 +08:00 committed by Patrick Georgi
parent a0218958a0
commit 4e39c824e0
3 changed files with 86 additions and 0 deletions
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40
src/include/crc_byte.h Normal file
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@ -0,0 +1,40 @@
/*
* This file is part of the coreboot project.
*
* Copyright (C) 2019 HardenedLinux
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef CRC_BYTE_H
#define CRC_BYTE_H
#include <stdint.h>
/* This function is used to calculate crc7 byte by byte, with polynomial
* x^7 + x^3 + 1.
*
* prev_crc: old crc result (0 for first)
* data: new byte
* return value: new crc result
*/
uint8_t crc7_byte(uint8_t prev_crc, uint8_t data);
/* This function is used to calculate crc16 byte by byte, with polynomial
* x^16 + x^12 + x^5 + 1.
*
* prev_crc: old crc result (0 for first)
* data: new byte
* return value: new crc result
*/
uint16_t crc16_byte(uint16_t prev_crc, uint8_t data);
#endif /* CRC_BYTE_H */

8
src/lib/Makefile.inc
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@ -249,6 +249,14 @@ postcar-y += string.c
ramstage-y += string.c
smm-y += string.c
decompressor-y += crc_byte.c
bootblock-y += crc_byte.c
verstage-y += crc_byte.c
romstage-y += crc_byte.c
postcar-y += crc_byte.c
ramstage-y += crc_byte.c
smm-y += crc_byte.c
postcar-y += bootmode.c
postcar-y += boot_device.c
postcar-y += cbfs.c

38
src/lib/crc_byte.c Normal file
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@ -0,0 +1,38 @@
/*
* This file is part of the coreboot project.
*
* Copyright (C) 2019 HardenedLinux
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <crc_byte.h>
uint8_t crc7_byte(uint8_t prev_crc, uint8_t data)
{
const uint8_t g = 0x89;
prev_crc ^= data;
for (int i = 0; i < 8; i++) {
if (prev_crc & 0x80)
prev_crc ^= g;
prev_crc <<= 1;
}
return prev_crc;
}
uint16_t crc16_byte(uint16_t prev_crc, uint8_t data)
{
prev_crc = (uint8_t)(prev_crc >> 8)|(prev_crc << 8);
prev_crc ^= data;
prev_crc ^= (uint8_t)(prev_crc & 0xff) >> 4;
prev_crc ^= (prev_crc << 8) << 4;
prev_crc ^= ((prev_crc & 0xff) << 4) << 1;
return prev_crc;
}