/*
 *  ich9deblob.c
 *  This file is part of the ich9deblob utility from the libreboot project
 * 
 * Purpose: disable and remove the ME from ich9m/gm45 machines in coreboot.
 *
 *  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/>.
 */
 
/*
 * Read a factory.rom dump (ich9m/gm45 machines) and 
 * modify the flash descriptor to remove all regions except descriptor,
 * Gbe and BIOS. Set BIOS region to full size of the ROM image (after
 * the flash descriptor and gbe). Basically, deblob the descriptor.
 * 
 * This will will generate a concatenated descriptor+gbe dump suitable
 * for use in libreboot. Currently tested: ThinkPad X200 (coreboot/libreboot)
 */
 
// See docs/hcl/x200_remove_me.html for info plus links to datasheet (also linked below)

// Info about flash descriptor (read page 850 onwards):
// * http://www.intel.co.uk/content/dam/doc/datasheet/io-controller-hub-9-datasheet.pdf

// Info about Gbe region (read whole datasheet):
// * http://www.intel.co.uk/content/dam/doc/application-note/i-o-controller-hub-9m-82567lf-lm-v-nvm-map-appl-note.pdf
// * https://communities.intel.com/community/wired/blog/2010/10/14/how-to-basic-eeprom-checksums

#include <stdio.h>
#include <string.h>
#include "descriptor/descriptor.h" // structs describing what's in the descriptor region
#include "gbe/gbe.h" // structs describing what's in the gbe region, plus functions that use them
#include "x86compatibility.c" // compatibility checks. this utility is not portable yet.

int main(int argc, char *argv[])
{
	// descriptor region. Will have an actual descriptor struct mapped to it (from the factory.rom dump)
	// and then it will be modified (deblobbed) to remove the ME/AMT
	char factoryDescriptorBuffer[DESCRIPTORREGIONSIZE];
	struct DESCRIPTORREGIONRECORD factoryDescriptorStruct;
	char deblobbedDescriptorBuffer[DESCRIPTORREGIONSIZE];
	struct DESCRIPTORREGIONRECORD deblobbedDescriptorStruct;
	
	// gbe region. Well have actual gbe buffer mapped to it (from the factory.rom dump)
	// and then it will be modified to correct the main region
	char factoryGbeBuffer8k[GBEREGIONSIZE];
	struct GBEREGIONRECORD_8K factoryGbeStruct8k;
	char deblobbedGbeBuffer8k[GBEREGIONSIZE];
	struct GBEREGIONRECORD_8K deblobbedGbeStruct8k;
	
	// Used to store the location of the Gbe
	// region inside the factory.rom image.
	unsigned int factoryGbeRegionStart;
	
	// names of the files that this utility will handle
	char* factoryRomFilename = "factory.rom"; // user-supplied factory.bin dump (original firmware)
	char* deblobbedDescriptorFilename = "deblobbed_descriptor.bin"; // descriptor+gbe: to be dd'd to beginning of a libreboot image
	
	// Used when reading the factory.rom to extract descriptor/gbe regions
	unsigned int bufferLength;
	
	// For storing the size of the factory.rom dump in bytes
	unsigned int factoryRomSize;
	
	// -----------------------------------------------------------------------------------------------
	
	// Compatibility checks. This version of ich9deblob is not yet porable.
	if (systemOrCompilerIncompatible(factoryDescriptorStruct, factoryGbeStruct8k)) return 1;
	
	// -----------------------------------------------------------------------------------------------

	// Open factory.rom, needed for extracting descriptor and gbe
	// -----------------------------------------------
	FILE* fileStream = NULL;
	fileStream = fopen(factoryRomFilename, "rb"); // open factory.rom
	if (NULL == fileStream)
	{
		printf("\nerror: could not open factory.rom\n");
		return 1;
	}
	printf("\nfactory.rom opened successfully\n");
	// -----------------------------------------------
	
	// Get the descriptor region dump from the factory.rom
	// (goes in factoryDescriptorBuffer variable)
	bufferLength = fread(factoryDescriptorBuffer, sizeof(char), DESCRIPTORREGIONSIZE, fileStream);
	if (DESCRIPTORREGIONSIZE != bufferLength) // 
	{
		printf("\nerror: could not read descriptor from factory.rom (%i) bytes read\n", bufferLength);
		return 1;
	}
	printf("\ndescriptor region read successfully\n");
	// copy descriptor buffer into descriptor struct memory
	// factoryDescriptorStruct is an instance of a struct that actually
	// defines the locations of all these variables in the descriptor,
	// as defined in the datasheets. This allows us to map the extracted
	// descriptor over the struct so that it can then be modified
	// for libreboot's purpose
	memcpy(&factoryDescriptorStruct, &factoryDescriptorBuffer, DESCRIPTORREGIONSIZE);
	// ^ the above is just for reference if needed. The modifications will be made here:
	memcpy(&deblobbedDescriptorStruct, &factoryDescriptorBuffer, DESCRIPTORREGIONSIZE);
	
	// -----------------------------------------------------------------------------------------------
	
	// Get the gbe region dump from the factory.rom

	// get original GBe region location
	// (it will be moved to the beginning of the flash, after the descriptor region)
	// note for example, factoryGbeRegionStart is set to <<FLREGIONBITSHIFT of actual address (in C). this is how the addresses
	// are stored in the descriptor.
	factoryGbeRegionStart = factoryDescriptorStruct.regionSection.flReg3.BASE << FLREGIONBITSHIFT;

	// Set offset so that we can read the data from
	// the gbe region
	fseek(fileStream, factoryGbeRegionStart, SEEK_SET);
	// Read the gbe data from the factory.rom and put it in factoryGbeBuffer8k
	bufferLength = fread(factoryGbeBuffer8k, sizeof(char), GBEREGIONSIZE, fileStream);
	if (GBEREGIONSIZE != bufferLength)
	{
		printf("\nerror: could not read GBe region from factory.rom (%i) bytes read\n", bufferLength);
		return 1;
	}
	printf("\ngbe (8KiB) region read successfully\n");
	// copy gbe buffer into gbe struct memory
	// factoryGbeStruct8k is an instance of a struct that actually
	// defines the locations of all these variables in the gbe,
	// as defined in the datasheets. This allows us to map the extracted
	// gbe over the struct so that it can then be modified
	// for libreboot's purpose
	memcpy(&factoryGbeStruct8k, &factoryGbeBuffer8k, GBEREGIONSIZE);
	// the original factoryGbeStruct8k is only reference. Changes go here:
	memcpy(&deblobbedGbeStruct8k, &factoryGbeBuffer8k, GBEREGIONSIZE);

	// -----------------------------------------------------------------------------------------------

	// Get size of ROM image
	// This is needed for relocating the BIOS region (per descriptor)
	fseek(fileStream, 0L, SEEK_END);
	factoryRomSize = ftell(fileStream);

	printf("\nfactory.rom size: [%i] bytes\n", factoryRomSize);

	fclose(fileStream);
	
	// -----------------------------------------------------------------------------------------------

	// Disable the ME and Platform regions. Put Gbe at the beginning (after descriptor). 
	// Also, extend the BIOS region to fill the ROM image (after descriptor+gbe).
	deblobbedDescriptorStruct = deblobbedDescriptorStructFromFactory(factoryDescriptorStruct, factoryRomSize);

	// ----------------------------------------------------------------------------------------------------------------

	// Modify the Gbe descriptor (see function for details)
	deblobbedGbeStruct8k = deblobbedGbeStructFromFactory(factoryGbeStruct8k);

	// ----------------------------------------------------------------------------------------------------------------

	// Convert the deblobbed descriptor and gbe back to byte arrays, so that they
	// can more easily be written to files:
	// deblobbed descriptor region
	memcpy(&deblobbedDescriptorBuffer, &deblobbedDescriptorStruct, DESCRIPTORREGIONSIZE); // descriptor
	memcpy(&deblobbedGbeBuffer8k, &deblobbedGbeStruct8k, GBEREGIONSIZE); // gbe

	// delete old file before continuing
	remove(deblobbedDescriptorFilename);
	// open new file for writing the deblobbed descriptor+gbe
	fileStream = fopen(deblobbedDescriptorFilename, "ab");

	// write the descriptor region into the first part
	if (DESCRIPTORREGIONSIZE != fwrite(deblobbedDescriptorBuffer, sizeof(char), DESCRIPTORREGIONSIZE, fileStream))
	{
		printf("\nerror: writing descriptor region failed\n");
		return 1;
	}

	// add gbe to the end of the file
	if (GBEREGIONSIZE != fwrite(deblobbedGbeBuffer8k, sizeof(char), GBEREGIONSIZE, fileStream))
	{
		printf("\nerror: writing GBe region failed\n");
		return 1;
	}

	fclose(fileStream);

	printf("\ndeblobbed descriptor successfully created: deblobbed_descriptor.bin \n");

	// -------------------------------------------------------------------------------------

	printf("\nNow do: dd if=deblobbed_descriptor.bin of=libreboot.rom bs=1 count=12k conv=notrunc");
	printf("\n(in other words, add the modified descriptor+gbe to your ROM image)\n");

	return 0;
}