diff options
Diffstat (limited to 'resources/utilities/ich9deblob/src/gbe')
| -rw-r--r-- | resources/utilities/ich9deblob/src/gbe/gbe.c | 124 | ||||
| -rw-r--r-- | resources/utilities/ich9deblob/src/gbe/gbe.h | 101 |
2 files changed, 225 insertions, 0 deletions
diff --git a/resources/utilities/ich9deblob/src/gbe/gbe.c b/resources/utilities/ich9deblob/src/gbe/gbe.c new file mode 100644 index 0000000..9eee828 --- /dev/null +++ b/resources/utilities/ich9deblob/src/gbe/gbe.c @@ -0,0 +1,124 @@ +/* + * gbe/gbe.c + * This file is part of the ich9deblob utility from the libreboot project + * + * Copyright (C) 2014 Steve Shenton <sgsit@libreboot.org> + * Francis Rowe <info@gluglug.org.uk> + * + * 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, either version 3 of the License, or + * (at your option) any later version. + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/* + * Provide gbe related functions. + */ + +/* structs describing the data from gbe region */ +#include "gbe.h" + +/* + * --------------------------------------------------------------------- + * Gbe functions: + * --------------------------------------------------------------------- + */ + +/* Read a 16-bit unsigned int from a supplied region buffer */ +unsigned short gbeGetRegionWordFrom8kBuffer(int index, char* regionData) +{ + return *((unsigned short*)(regionData + (index * 2))); +} + +/* + * gbe checksum calculation (algorithm based on datasheet) + */ +unsigned short gbeGetChecksumFrom8kBuffer(char* regionData, unsigned short desiredValue, int byteOffset) +{ + int i; + + /* + * byteOffset defines the byte address where the gbe begins in the buffer "regionData". + * However, this function works with 16-bit words. Shift the byte offset to the right for the word (16-bit) offset. + */ + int wordOffset = byteOffset >> 1; + + unsigned short regionWord; /* store words here for adding to checksum */ + unsigned short checksum = 0; /* this gbe's checksum */ + + for (i = 0; i < 0x3F; i++) { + regionWord = gbeGetRegionWordFrom8kBuffer(i+wordOffset, regionData); + checksum += regionWord; + } + checksum = desiredValue - checksum; + return checksum; +} + +/* checksum calculation for 4k gbe struct (algorithm based on datasheet) */ +unsigned short gbeGetChecksumFrom4kStruct(struct GBEREGIONRECORD_4K gbeStruct4k, unsigned short desiredValue) +{ + char gbeBuffer4k[GBEREGIONSIZE_4K]; + memcpy(&gbeBuffer4k, &gbeStruct4k, GBEREGIONSIZE_4K); + return gbeGetChecksumFrom8kBuffer(gbeBuffer4k, desiredValue, 0); +} + +/* modify the gbe region extracted from a factory.rom dump */ +struct GBEREGIONRECORD_8K deblobbedGbeStructFromFactory(struct GBEREGIONRECORD_8K factoryGbeStruct8k) +{ + /* + * Correct the main gbe region. By default, the X200 (as shipped from Lenovo) comes + * with a broken main gbe region, where the backup gbe region is used instead. Modify + * it so that the main region is usable. + */ + + struct GBEREGIONRECORD_8K deblobbedGbeStruct8k; + memcpy(&deblobbedGbeStruct8k, &factoryGbeStruct8k, GBEREGIONSIZE_8K); + + deblobbedGbeStruct8k.backup.checkSum = gbeGetChecksumFrom4kStruct(deblobbedGbeStruct8k.backup, GBECHECKSUMTOTAL); + memcpy(&deblobbedGbeStruct8k.main, &deblobbedGbeStruct8k.backup, GBEREGIONSIZE_4K); + + return deblobbedGbeStruct8k; +} + +/* + * --------------------------------------------------------------------- + * Debugging functions: + * --------------------------------------------------------------------- + */ + +/* + * show debugging info: show calculated (correct) gbe checksum and what + * is actually stored, in a 4K gbe struct. Only for a single region. + */ +void printGbeChecksumDataFromStruct4k(struct GBEREGIONRECORD_4K gbeStruct4k, char* romName, char* regionName) +{ + printf( + "%s Gbe (%s): calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", + romName, + regionName, + gbeGetChecksumFrom4kStruct(gbeStruct4k, GBECHECKSUMTOTAL), + gbeStruct4k.checkSum + ); + + return; +} + +/* + * show debugging info: show calculated (correct) gbe checksum and what + * is actually stored, in a 8K gbe struct. Do so for main and backup regions. + */ +void printGbeChecksumDataFromStruct8k(struct GBEREGIONRECORD_8K gbeStruct8k, char* romName) +{ + printGbeChecksumDataFromStruct4k(gbeStruct8k.main, romName, "main"); + printGbeChecksumDataFromStruct4k(gbeStruct8k.backup, romName, "backup"); + + return; +} diff --git a/resources/utilities/ich9deblob/src/gbe/gbe.h b/resources/utilities/ich9deblob/src/gbe/gbe.h new file mode 100644 index 0000000..bfcc002 --- /dev/null +++ b/resources/utilities/ich9deblob/src/gbe/gbe.h @@ -0,0 +1,101 @@ +/* + * gbe/gbe.h + * This file is part of the ich9deblob utility from the libreboot project + * + * Copyright (C) 2014 Steve Shenton <sgsit@libreboot.org> + * Francis Rowe <info@gluglug.org.uk> + * + * 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, either version 3 of the License, or + * (at your option) any later version. + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/* + * Purpose: provide struct representing gbe region. + * Map actual buffers of this regions, directly to instances of these + * structs. This makes working with gbe really easy. + */ + +/* + * bit fields used, corresponding to datasheet. See links to datasheets + * and documentation in ich9deblob.c + */ + +#ifndef GBESTRUCT_H +#define GBESTRUCT_H + +#include <stdio.h> +#include <string.h> + +/* Size of the full gbe region in bytes */ +#define GBEREGIONSIZE_8K 0x2000 +/* + * Size of each sub-region in gbe. + * gbe contains two regions which + * can be identical: main and backup. + * These are each half the size of the full region + */ +#define GBEREGIONSIZE_4K 0x1000 + +/* + * When adding up the first 0x3F 16-bit words + * in a 4KiB GBE region, it should be equal + * to 0xBABA + */ +#define GBECHECKSUMTOTAL 0xBABA + +/* + * These will have a modified descriptor+gbe based on what's in the factory.rom + * These will be joined into a single 12KiB buffer (descriptor, then gbe) and saved to a file + * NOTE: The GBE region of 8K is actually 2x 4K regions in a single region; both 4K blocks can be identical (and by default, are) + * The 2nd one is a "backup", but we don't know when it's used. perhaps it's used when the checksum on the first one does not match? + */ + +/* + * --------------------------------------------------------------------- + * Gbe struct representing the data: + * --------------------------------------------------------------------- + */ + +struct GBEREGIONRECORD_4K { + unsigned char macAddress[6]; /* 0x03 words, or 0x06 bytes */ + unsigned char otherStuff[120]; /* 0x3c words, or 0x7E bytes */ + unsigned short checkSum; /* when added to the sum of all words above, this should match GBECHECKSUMTOTAL */ + unsigned char padding1[3968]; +}; + +/* main and backup region in gbe */ +struct GBEREGIONRECORD_8K { + struct GBEREGIONRECORD_4K main; + struct GBEREGIONRECORD_4K backup; + /* + * Backup region: + * This is actually "main" on X200, since the real main has a bad checksum + * and other errors. You should do what you need on this one (if modifying + * lenovobios's gbe region) and then copy to main + */ +}; + +/* + * --------------------------------------------------------------------- + * Function declarations (keep gcc/make happy. check them in gbe.c) + * --------------------------------------------------------------------- + */ + +unsigned short gbeGetRegionWordFrom8kBuffer(int index, char* regionData); +unsigned short gbeGetChecksumFrom8kBuffer(char* regionData, unsigned short desiredValue, int byteOffset); +unsigned short gbeGetChecksumFrom4kStruct(struct GBEREGIONRECORD_4K gbeStruct4k, unsigned short desiredValue); +struct GBEREGIONRECORD_8K deblobbedGbeStructFromFactory(struct GBEREGIONRECORD_8K factoryGbeStruct8k); +void printGbeChecksumDataFromStruct4k(struct GBEREGIONRECORD_4K gbeStruct4k, char* romName, char* regionName); +void printGbeChecksumDataFromStruct8k(struct GBEREGIONRECORD_8K gbeStruct8k, char* romName); + +#endif |