From a8b13d23f29a08026eaa308b8b09be7e9d1ff5a6 Mon Sep 17 00:00:00 2001
From: Francis Rowe <info@gluglug.org.uk>
Date: Thu, 25 Dec 2014 16:25:49 -0500
Subject: ich9deblob: moved src to src/, .o files to obj/

---
(limited to 'resources/utilities/ich9deblob/src/gbe/gbe.c')

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;
+}
--
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