/*
 * savegame_manager: a tool to backup and restore savegames from Nintendo
 *  DS cartridges. Nintendo DS and all derivative names are trademarks
 *  by Nintendo. EZFlash 3-in-1 is a trademark by EZFlash.
 *
 * gba.cpp: Functions for working with the GBA-slot on a Nintendo DS.
 *    EZFlash 3-in-1 functions are found in dsCard.h/.cpp
 *
 * Copyright (C) Pokedoc (2010)
 */
/* 
 * 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 2 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, write to the Free Software Foundation, Inc., 
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <nds.h>
#include <fat.h>

#include <sys/iosupport.h>
#include <unistd.h>

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <sys/unistd.h>
#include <algorithm>
#include <nds/dma.h>


#include <dirent.h>

#include "gba.h"
#include "dsCard.h"

#include "display.h"
#include "globals.h"
#include "strings.h"

inline u32 min(u32 i, u32 j) { return (i < j) ? i : j;}
inline u32 max(u32 i, u32 j) { return (i > j) ? i : j;}



// -----------------------------------------------------
#define MAGIC_EEPR 0x52504545
#define MAGIC_SRAM 0x4d415253
#define MAGIC_FLAS 0x53414c46

#define MAGIC_H1M_ 0x5f4d3148

saveTypeGBA GetSlot2SaveType(cartTypeGBA type) {
	if (type == CART_GBA_NONE)
		return SAVE_GBA_NONE;
		
	// Search for any one of the magic version strings in the ROM.
	uint32 *data = (uint32*)0x08000000;
	
	for (int i = 0; i < (0x02000000 >> 2); i++, data++) {
		if (*data == MAGIC_EEPR)
			return SAVE_GBA_EEPROM_8; // TODO: Try to figure out 512 bytes version...
		if (*data == MAGIC_SRAM)
			return SAVE_GBA_SRAM_32;
		if (*data == MAGIC_FLAS) {
			uint32 *data2 = data + 1;
			if (*data2 == MAGIC_H1M_)
				return SAVE_GBA_FLASH_128;
			else
				return SAVE_GBA_FLASH_64;
		}
	}
	return SAVE_GBA_NONE;
};

cartTypeGBA GetSlot2Type(uint32 id)
{		
	if (id == 0x53534150)
		// All conventional GBA flash cards identify themselves as "PASS"
		return CART_GBA_FLASH;
	else {
		return CART_GBA_GAME;
	}
};

// -----------------------------------------------------------
bool gbaIsGame()
{
	// look for some magic bytes of the compressed Nintendo logo
	uint32 *data = (uint32*)0x08000004;
	
	if (*data == 0x51aeff24) {
		data ++; data ++;
		if (*data == 0x0a82843d)
			return true;
	}
	return false;
}

uint8 gbaGetSaveType()
{
	// Search for any one of the magic version strings in the ROM. They are always dword-aligned.
	uint32 *data = (uint32*)0x08000000;
	
	for (int i = 0; i < (0x02000000 >> 2); i++, data++) {
		if (*data == MAGIC_EEPR) {
			// 2 versions: 512 bytes / 8 kB
			return 2; // TODO: Try to figure out how to ID the 512 bytes version... hard way? write/restore!
		}
		if (*data == MAGIC_SRAM) {
			// *always* 32 kB
			return 3;
		}
		if (*data == MAGIC_FLAS) {
			// 64 kB oder 128 kB
			uint32 *data2 = data + 1;
			if (*data2 == MAGIC_H1M_)
				return 5;
			else
				return 4;
		}
	}
	
	return 0;
}

uint32 gbaGetSaveSizeLog2(uint8 type)
{
	if (type == 255)
		type = gbaGetSaveType();
	
	switch (type) {
		case 1:
			return 9;
		case 2:
			return 13;
		case 3:
			return 15;
		case 4:
			return 16;
		case 5:
			return 17;
		case 0:
		default:
			return 0;
	}
}

uint32 gbaGetSaveSize(uint8 type)
{
	return 1 << gbaGetSaveSizeLog2(type);
}

// local function
void gbaEepromRead8Bytes(u8 *out, u32 addr, bool short_addr = false)
{
	// TODO: this still does not work... figure out somehow how to do it right!
	
	// waitstates - this is what Rudolph uses...
	*(volatile unsigned short *)0x04000204 = 0x4317; 

	// maximal length of the buffer
	u16 buf[68];
	
	// Prepare a "read" command.
	u16 length;
	// raw command
	buf[0] = 1;
	buf[1] = 1;
	// address
	if (short_addr) {
		length = 9;
		buf[2] = addr >> 5;
		buf[3] = addr >> 4;
		buf[4] = addr >> 3;
		buf[5] = addr >> 2;
		buf[6] = addr >> 1;
		buf[7] = addr;
		buf[8] = 0;
	} else {
		length = 17;
		buf[2] = addr >> 13;
		buf[3] = addr >> 12;
		buf[4] = addr >> 11;
		buf[5] = addr >> 10;
		buf[6] = addr >> 9;
		buf[7] = addr >> 8;
		buf[8] = addr >> 7;
		buf[9] = addr >> 6;
		buf[10] = addr >> 5;
		buf[11] = addr >> 4;
		buf[12] = addr >> 3;
		buf[13] = addr >> 2;
		buf[14] = addr >> 1;
		buf[15] = addr;
		buf[16] = 0;
	}
	for (int i = 0; i < 17; i++) {
		if (buf[i])
			buf[i] = 255;
		else
			buf[i] = 0;
	}
	
	static u32 eeprom = 0x09ffff00;

	// send command to eeprom
	displayStateF(STR_STR, "Sending command");
	// commenting this out or not does not have any impact on the EEPROM device. Therefore,
	//  the following command does not "make" it to the hardware!
	DC_FlushRange(&buf[0], sizeof(buf));
	DMA_SRC(3) = (uint32)&buf[0];
	DMA_DEST(3) = (uint32)eeprom;
	// there is a bit for eeprom access, but it only seems to freeze the transfer!?
	//DMA_CR(3) = DMA_COPY_HALFWORDS | DMA_START_CARD | length; // this bit is expanding to "3 bits"
	//DMA_CR(3) = DMA_COPY_HALFWORDS | length;
	DMA_CR(3) = DMA_COPY_HALFWORDS | (6 << 27) | length;
	while(DMA_CR(3) & DMA_BUSY);
	//while ((*(u16*)0x09ffff00 & 1) == 0);

	// get answer from eeprom
	displayStateF(STR_STR, "listening");
	DC_FlushRange(&buf[0], sizeof(buf));
	DMA_SRC(3) = (uint32)eeprom;
	DMA_DEST(3) = (uint32)&buf[0];
	// there is a bit for eeprom access, but it only seems to freeze the transfer!?
	//DMA_CR(3) = DMA_COPY_HALFWORDS | DMA_START_CARD | 68; // this bit is expanding to "3 bits"
	//DMA_CR(3) = DMA_COPY_HALFWORDS | 68;
	DMA_CR(3) = DMA_COPY_HALFWORDS | (6 << 27) | 68;
	while(DMA_CR(3) & DMA_BUSY);
	//while ((*(u16*)0x09ffff00 & 1) == 0);

/*
	// Extract data (there is only one *bit* per halfword!)
	u16 *in_pos = &buf[4]; 
	u8 *out_pos = out; 
	u8 out_byte;
	for(s8 byte = 7; byte >= 0; --byte )
	{
		out_byte = 0;
		for(s8 bit = 7; bit >= 0; --bit )
		{
			out_byte += ((*in_pos++)&1)<<bit;
		}
		*out_pos++ = out_byte;
	}
	*/
	// let us study what the hardware *does* give us!
	for (u8 i = 0; i < 8; i++)
		*out++ = buf[i+4];
}

// local function
void gbaEepromWrite8Bytes(u8 *out, u32 addr, bool short_addr = false)
{
	// TODO: this still does not work... figure out somehow how to do it right!
	
	// don't do anything unless we know what we are doing!
#if 0
	// waitstates - this is what Rudolph uses...
	*(volatile unsigned short *)0x04000204 = 0x4317; 

	// maximal length of the buffer
	u16 buf[68];
	
	// Prepare a "read" command.
	u16 length;
	// raw command
	buf[0] = 1;
	buf[1] = 1;
	// address
	if (short_addr) {
		length = 9;
		buf[2] = addr >> 5;
		buf[3] = addr >> 4;
		buf[4] = addr >> 3;
		buf[5] = addr >> 2;
		buf[6] = addr >> 1;
		buf[7] = addr;
		buf[8] = 0;
	} else {
		length = 17;
		buf[2] = addr >> 13;
		buf[3] = addr >> 12;
		buf[4] = addr >> 11;
		buf[5] = addr >> 10;
		buf[6] = addr >> 9;
		buf[7] = addr >> 8;
		buf[8] = addr >> 7;
		buf[9] = addr >> 6;
		buf[10] = addr >> 5;
		buf[11] = addr >> 4;
		buf[12] = addr >> 3;
		buf[13] = addr >> 2;
		buf[14] = addr >> 1;
		buf[15] = addr;
		buf[16] = 0;
	}
	
	// send command to eeprom
	displayStateF(STR_STR, "Sending command");
	static u32 eeprom = 0x09ffff00;
	DMA_SRC(3) = (uint32)&buf[0];
	DMA_DEST(3) = (uint32)eeprom;
	// there is a bit for eeprom access, but it only seems to freeze the transfer!?
	//DMA_CR(3) = DMA_COPY_HALFWORDS | DMA_START_CARD | length;
	DMA_CR(3) = DMA_COPY_HALFWORDS | length;
	while(DMA_CR(3) & DMA_BUSY);

	// get answer from eeprom
	displayStateF(STR_STR, "listening");
	DMA_SRC(3) = (uint32)eeprom;
	DMA_DEST(3) = (uint32)&buf[0];
	// there is a bit for eeprom access, but it only seems to freeze the transfer!?
	DMA_CR(3) = DMA_COPY_HALFWORDS | DMA_START_CARD | 68;
	//DMA_CR(3) = DMA_COPY_HALFWORDS | 68;
	while(DMA_CR(3) & DMA_BUSY);

	// Extract data (there is only one *bit* per halfword!)
	// TODO: convert this to write format
	u16 *in_pos = &buf[4]; 
	u8 *out_pos = out; 
	u8 out_byte;
	for(s8 byte = 7; byte >= 0; --byte )
	{
		out_byte = 0;
		for(s8 bit = 7; bit >= 0; --bit )
		{
			out_byte += ((*in_pos++)&1)<<bit;
		}
		*out_pos++ = out_byte;
	}
#endif
}

bool gbaReadSave(u8 *dst, u32 src, u32 len, u8 type)
{
	int nbanks = 2; // for type 4,5
	bool eeprom_long = true;
	
	switch (type) {
	case 1: {
		eeprom_long = false;
		}
	case 2: {
		int start, end;
		start = src >> 3;
		end = (src + len - 1) >> 3;
		u8 *tmp = (u8*)malloc((end-start+1) << 3);
		u8 *ptr = tmp;
		for (int j = start; j <= end; j++, ptr+=8) {
			gbaEepromRead8Bytes(ptr, j, eeprom_long);
		}
		memcpy(dst, tmp, len);
		free(tmp);
		break;
		}
	case 3: {
		// SRAM: blind copy
		int start = 0x0a000000 + src;
		u8 *tmpsrc = (u8*)start;
		sysSetBusOwners(true, true);
		for (u32 i = 0; i < len; i++, tmpsrc++, dst++)
			*dst = *tmpsrc;
		break;
		}
	case 4:
		// FLASH - must be opend by register magic, then blind copy
		nbanks = 1;
	case 5:
		for (int j = 0; j < nbanks; j++) {
			// we need to wait a few cycles before the hardware reacts!
			*(u8*)0x0a005555 = 0xaa;
			swiDelay(10);
			*(u8*)0x0a002aaa = 0x55;
			swiDelay(10);
			*(u8*)0x0a005555 = 0xb0;
			swiDelay(10);
			*(u8*)0x0a000000 = (u8)j;
			swiDelay(10);
			u32 start, sublen;
			if (j == 0) {
				start = 0x0a000000 + src;
				sublen = (src < 0x10000) ? min(len, (1 << 16) - src) : 0;
			} else if (j == 1) {
				start = max(0x09ff0000 + src, 0x0a000000);
				sublen = (src + len < 0x10000) ? 0 : min(len, len - (0x10000 - src));
			}
			u8 *tmpsrc = (u8*)start;
			sysSetBusOwners(true, true);
			for (u32 i = 0; i < sublen; i++, tmpsrc++, dst++)
				*dst = *tmpsrc;
		}
		break;
	}
	return true;
}

bool gbaIsAtmel()
{
	*(u8*)0x0a005555 = 0xaa;
	swiDelay(10);
	*(u8*)0x0a002aaa = 0x55;
	swiDelay(10);
	*(u8*)0x0a005555 = 0x90; // ID mode
	swiDelay(10);
	//
	u8 dev = *(u8*)0x0a000001;
	u8 man = *(u8*)0x0a000000;
	//
	*(u8*)0x0a005555 = 0xaa;
	swiDelay(10);
	*(u8*)0x0a002aaa = 0x55;
	swiDelay(10);
	*(u8*)0x0a005555 = 0xf0; // leave ID mode
	swiDelay(10);
	//
	//char txt[128];
	sprintf(txt, "Man: %x, Dev: %x", man, dev);
	displayStateF(STR_STR, txt);
	if ((man == 0x3d) && (dev == 0x1f))
		return true;
	else
		return false;
}

bool gbaWriteSave(u32 dst, u8 *src, u32 len, u8 type)
{
	int nbanks = 2; // for type 4,5
	bool eeprom_long = true;
	
	switch (type) {
	case 1: {
		eeprom_long = false;
		}
	case 2: {
	/*
		int start, end;
		start = src >> 3;
		end = (src + len - 1) >> 3;
		u8 *tmp = (u8*)malloc((end-start+1) << 3);
		u8 *ptr = tmp;
		for (int j = start; j <= end; j++, ptr+=8) {
			gbaEepromWrite8Bytes(ptr, j, eeprom_long);
		}
		memcpy(dst, tmp, len);
		free(tmp);
		*/
		break;
		}
	case 3: {
		// SRAM: blind write
		u32 start = 0x0a000000 + dst;
		u8 *tmpdst = (u8*)start;
		sysSetBusOwners(true, true);
		for (u32 i = 0; i < len; i++, tmpdst++, src++)
			*tmpdst = *src;
			swiDelay(10); // mabe we don't need this, but better safe than sorry
		break;
		}
	case 4: {
		bool atmel = gbaIsAtmel();
		if (atmel) {
			// only 64k, no bank switching required
			u32 len7 = len >> 7;
			u8 *tmpdst = (u8*)(0x0a000000+dst);
			for (u32 j = 0; j < len7; j++) {
				u32 ime = enterCriticalSection();
				*(u8*)0x0a005555 = 0xaa;
				swiDelay(10);
				*(u8*)0x0a002aaa = 0x55;
				swiDelay(10);
				*(u8*)0x0a005555 = 0xa0;
				swiDelay(10);
				for (int i = 0; i < 128; i++) {
					*tmpdst = *src;
					swiDelay(10);
				}
				leaveCriticalSection(ime);
				while (*tmpdst != *src) {swiDelay(10);}
			}
			break;
		}
		nbanks = 1;
		}
	case 5:
		// FLASH - must be opend by register magic, erased and then rewritten
		// FIXME: currently, you can only write "all or nothing"
		nbanks = 2;
		for (int j = 0; j < nbanks; j++) {
			*(u8*)0x0a005555 = 0xaa;
			swiDelay(10);
			*(u8*)0x0a002aaa = 0x55;
			swiDelay(10);
			*(u8*)0x0a005555 = 0xb0;
			swiDelay(10);
			*(u8*)0x0a000000 = (u8)j;
			swiDelay(10);
			//
			u32 start, sublen;
			if (j == 0) {
				start = 0x0a000000 + dst;
				sublen = (dst < 0x10000) ? min(len, (1 << 16) - dst) : 0;
			} else if (j == 1) {
				start = max(0x09ff0000 + dst, 0x0a000000);
				sublen = (dst + len < 0x10000) ? 0 : min(len, len - (0x10000 - dst));
			}
			u8 *tmpdst = (u8*)start;
			sysSetBusOwners(true, true);
			for (u32 i = 0; i < sublen; i++, tmpdst++, src++) {
				// we need to wait a few cycles before the hardware reacts!
				*(u8*)0x0a005555 = 0xaa;
				swiDelay(10);
				*(u8*)0x0a002aaa = 0x55;
				swiDelay(10);
				*(u8*)0x0a005555 = 0xa0; // write byte command
				swiDelay(10);
				//
				*tmpdst = *src;
				swiDelay(10);
				//
				while (*tmpdst != *src) {swiDelay(10);}
			}
		}
		break;
	}
	return true;
}

bool gbaFormatSave(u8 type)
{
	switch (type) {
		case 1:
		case 2:
			// TODO: eeprom is not supported yet
			break;
		case 3:
			memset(data, 0, 1 << 15);
			gbaWriteSave(0, data, 1 << 15, 3);
			break;
		case 4:
		case 5:
			*(u8*)0x0a005555 = 0xaa;
			swiDelay(10);
			*(u8*)0x0a002aaa = 0x55;
			swiDelay(10);
			*(u8*)0x0a005555 = 0x80; // erase command
			swiDelay(10);
			*(u8*)0x0a005555 = 0xaa;
			swiDelay(10);
			*(u8*)0x0a002aaa = 0x55;
			swiDelay(10);
			*(u8*)0x0a005555 = 0x10; // erase entire chip
			swiDelay(10);
			while (*(u8*)0x0a000000 != 0xff)
				swiDelay(10);
			break;
	}
	return true;
}