diff options
Diffstat (limited to 'resources/utilities/ich9deblob/gbe/gbe.h')
| -rw-r--r-- | resources/utilities/ich9deblob/gbe/gbe.h | 81 |
1 files changed, 6 insertions, 75 deletions
diff --git a/resources/utilities/ich9deblob/gbe/gbe.h b/resources/utilities/ich9deblob/gbe/gbe.h index 0e3f059..9647d80 100644 --- a/resources/utilities/ich9deblob/gbe/gbe.h +++ b/resources/utilities/ich9deblob/gbe/gbe.h @@ -33,9 +33,6 @@ #ifndef GBESTRUCT_H #define GBESTRUCT_H -#include <stdio.h> -#include <string.h> - /* Size of the full gbe region in bytes */ #define GBEREGIONSIZE_8K 0x2000 /* @@ -80,79 +77,13 @@ struct GBEREGIONRECORD_8K { /* * --------------------------------------------------------------------- - * Gbe functions: + * Function declarations (keep gcc/make happy. check them in gbe.c) * --------------------------------------------------------------------- */ - -/* Read a 16-bit unsigned int from a supplied region buffer */ -unsigned short gbeGetRegionWordFrom8kBuffer(int index, char* regionData) -{ - return *((unsigned short*)(regionData + (index * 2))); -} - -/* - * checksum calculation for 8k gbe region (algorithm based on datasheet) - * also works for 4k buffers, so long as isBackup remains false - */ -unsigned short gbeGetChecksumFrom8kBuffer(char* regionData, unsigned short desiredValue, char isBackup) -{ - int i; - - unsigned short regionWord; /* store words here for adding to checksum */ - unsigned short checksum = 0; /* this gbe's checksum */ - unsigned short offset = 0; /* in bytes, from the start of the gbe region. */ - - /* - * if isBackup is true, use 2nd gbe region ("backup" region) - * this function uses *word* not *byte* indexes, hence the bit shift. - */ - if (isBackup) offset = GBEREGIONSIZE_4K>>1; - - for (i = 0; i < 0x3F; i++) { - regionWord = gbeGetRegionWordFrom8kBuffer(i+offset, 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, 0xBABA); - memcpy(&deblobbedGbeStruct8k.main, &deblobbedGbeStruct8k.backup, GBEREGIONSIZE_4K); - - /* - * Debugging: - * calculate the 0x3F'th 16-bit uint to make the desired final checksum for GBe - * observed checksum matches (from X200 factory.rom dumps) on main: 0x3ABA 0x34BA 0x40BA. spec defined as 0xBABA. - * X200 ships with a broken main gbe region by default (invalid checksum, and more) - * The "backup" gbe regions on these machines are correct, though, and is what the machines default to - * For libreboot's purpose, we can do much better than that by fixing the main one... below is only debugging - */ - printf("\nfactory Gbe (main): calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(factoryGbeStruct8k.main, 0xBABA), factoryGbeStruct8k.main.checkSum); - printf("factory Gbe (backup) calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(factoryGbeStruct8k.backup, 0xBABA), factoryGbeStruct8k.backup.checkSum); - printf("\ndeblobbed Gbe (main): calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(deblobbedGbeStruct8k.main, 0xBABA), deblobbedGbeStruct8k.main.checkSum); - printf("deblobbed Gbe (backup) calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeGetChecksumFrom4kStruct(deblobbedGbeStruct8k.backup, 0xBABA), deblobbedGbeStruct8k.backup.checkSum); - - return deblobbedGbeStruct8k; -} + +unsigned short gbeGetRegionWordFrom8kBuffer(int index, char* regionData); +unsigned short gbeGetChecksumFrom8kBuffer(char* regionData, unsigned short desiredValue, char isBackup); +unsigned short gbeGetChecksumFrom4kStruct(struct GBEREGIONRECORD_4K gbeStruct4k, unsigned short desiredValue); +struct GBEREGIONRECORD_8K deblobbedGbeStructFromFactory(struct GBEREGIONRECORD_8K factoryGbeStruct8k); #endif |