vbagx/source/vba/Flash.cpp

// VisualBoyAdvance - Nintendo Gameboy/GameboyAdvance (TM) emulator.
// Copyright (C) 1999-2003 Forgotten
// Copyright (C) 2004 Forgotten and the VBA development team

// 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, 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 <stdio.h>
#include <string.h>
#include "GBA.h"
#include "Globals.h"
#include "Flash.h"
#include "Sram.h"
#include "Util.h"

#define FLASH_READ_ARRAY         0
#define FLASH_CMD_1              1
#define FLASH_CMD_2              2
#define FLASH_AUTOSELECT         3
#define FLASH_CMD_3              4
#define FLASH_CMD_4              5
#define FLASH_CMD_5              6
#define FLASH_ERASE_COMPLETE     7
#define FLASH_PROGRAM            8
#define FLASH_SETBANK            9

u8 flashSaveMemory[0x20000];
int flashState = FLASH_READ_ARRAY;
int flashReadState = FLASH_READ_ARRAY;
int flashSize = 0x10000;
int flashDeviceID = 0x1b;
int flashManufacturerID = 0x32;
int flashBank = 0;

static variable_desc flashSaveData[] = {
                                         { &flashState, sizeof(int) },
                                         { &flashReadState, sizeof(int) },
                                         { &flashSaveMemory[0], 0x10000 },
                                         { NULL, 0 }
                                       };

static variable_desc flashSaveData2[] = {
                                          { &flashState, sizeof(int) },
                                          { &flashReadState, sizeof(int) },
                                          { &flashSize, sizeof(int) },
                                          { &flashSaveMemory[0], 0x20000 },
                                          { NULL, 0 }
                                        };

static variable_desc flashSaveData3[] = {
                                          { &flashState, sizeof(int) },
                                          { &flashReadState, sizeof(int) },
                                          { &flashSize, sizeof(int) },
                                          { &flashBank, sizeof(int) },
                                          { &flashSaveMemory[0], 0x20000 },
                                          { NULL, 0 }
                                        };

void flashReset()
{
  flashState = FLASH_READ_ARRAY;
  flashReadState = FLASH_READ_ARRAY;
  flashBank = 0;
}

void flashSaveGame(gzFile gzFile)
{
  utilWriteData(gzFile, flashSaveData3);
}

void flashReadGame(gzFile gzFile, int version)
{
  if(version < SAVE_GAME_VERSION_5)
    utilReadData(gzFile, flashSaveData);
  else if(version < SAVE_GAME_VERSION_7)
    {
      utilReadData(gzFile, flashSaveData2);
      flashBank = 0;
      flashSetSize(flashSize);
    }
  else
    {
      utilReadData(gzFile, flashSaveData3);
    }
}

void flashSetSize(int size)
{
  //  log("Setting flash size to %d\n", size);
  flashSize = size;
  if(size == 0x10000)
    {
      flashDeviceID = 0x1b;
      flashManufacturerID = 0x32;
    }
  else
    {
      flashDeviceID = 0x13; //0x09;
      flashManufacturerID = 0x62; //0xc2;
    }
}

u8 flashRead(u32 address)
{
  //  log("Reading %08x from %08x\n", address, reg[15].I);
  //  log("Current read state is %d\n", flashReadState);
  address &= 0xFFFF;

  switch(flashReadState)
    {
    case FLASH_READ_ARRAY:
      return flashSaveMemory[(flashBank << 16) + address];
    case FLASH_AUTOSELECT:
      switch(address & 0xFF)
        {
        case 0:
          // manufacturer ID
          return flashManufacturerID;
        case 1:
          // device ID
          return flashDeviceID;
        }
      break;
    case FLASH_ERASE_COMPLETE:
      flashState = FLASH_READ_ARRAY;
      flashReadState = FLASH_READ_ARRAY;
      return 0xFF;
    };
  return 0;
}

void flashSaveDecide(u32 address, u8 byte)
{
  //  log("Deciding save type %08x\n", address);
  if(address == 0x0e005555)
    {
      saveType = 2;
      cpuSaveGameFunc = flashWrite;
    }
  else
    {
      saveType = 1;
      cpuSaveGameFunc = sramWrite;
    }

  (*cpuSaveGameFunc)(address, byte);
}

void flashWrite(u32 address, u8 byte)
{
  //  log("Writing %02x at %08x\n", byte, address);
  //  log("Current state is %d\n", flashState);
  address &= 0xFFFF;
  switch(flashState)
    {
    case FLASH_READ_ARRAY:
      if(address == 0x5555 && byte == 0xAA)
        flashState = FLASH_CMD_1;
      break;
    case FLASH_CMD_1:
      if(address == 0x2AAA && byte == 0x55)
        flashState = FLASH_CMD_2;
      else
        flashState = FLASH_READ_ARRAY;
      break;
    case FLASH_CMD_2:
      if(address == 0x5555)
        {
          if(byte == 0x90)
            {
              flashState = FLASH_AUTOSELECT;
              flashReadState = FLASH_AUTOSELECT;
            }
          else if(byte == 0x80)
            {
              flashState = FLASH_CMD_3;
            }
          else if(byte == 0xF0)
            {
              flashState = FLASH_READ_ARRAY;
              flashReadState = FLASH_READ_ARRAY;
            }
          else if(byte == 0xA0)
            {
              flashState = FLASH_PROGRAM;
            }
          else if(byte == 0xB0 && flashSize == 0x20000)
            {
              flashState = FLASH_SETBANK;
            }
          else
            {
              flashState = FLASH_READ_ARRAY;
              flashReadState = FLASH_READ_ARRAY;
            }
        }
      else
        {
          flashState = FLASH_READ_ARRAY;
          flashReadState = FLASH_READ_ARRAY;
        }
      break;
    case FLASH_CMD_3:
      if(address == 0x5555 && byte == 0xAA)
        {
          flashState = FLASH_CMD_4;
        }
      else
        {
          flashState = FLASH_READ_ARRAY;
          flashReadState = FLASH_READ_ARRAY;
        }
      break;
    case FLASH_CMD_4:
      if(address == 0x2AAA && byte == 0x55)
        {
          flashState = FLASH_CMD_5;
        }
      else
        {
          flashState = FLASH_READ_ARRAY;
          flashReadState = FLASH_READ_ARRAY;
        }
      break;
    case FLASH_CMD_5:
      if(byte == 0x30)
        {
          // SECTOR ERASE
          memset(&flashSaveMemory[(flashBank << 16) + (address & 0xF000)],
                 0,
                 0x1000);
          systemSaveUpdateCounter = SYSTEM_SAVE_UPDATED;
          flashReadState = FLASH_ERASE_COMPLETE;
        }
      else if(byte == 0x10)
        {
          // CHIP ERASE
          memset(flashSaveMemory, 0, flashSize);
          systemSaveUpdateCounter = SYSTEM_SAVE_UPDATED;
          flashReadState = FLASH_ERASE_COMPLETE;
        }
      else
        {
          flashState = FLASH_READ_ARRAY;
          flashReadState = FLASH_READ_ARRAY;
        }
      break;
    case FLASH_AUTOSELECT:
      if(byte == 0xF0)
        {
          flashState = FLASH_READ_ARRAY;
          flashReadState = FLASH_READ_ARRAY;
        }
      else if(address == 0x5555 && byte == 0xAA)
        flashState = FLASH_CMD_1;
      else
        {
          flashState = FLASH_READ_ARRAY;
          flashReadState = FLASH_READ_ARRAY;
        }
      break;
    case FLASH_PROGRAM:
      flashSaveMemory[(flashBank<<16)+address] = byte;
      systemSaveUpdateCounter = SYSTEM_SAVE_UPDATED;
      flashState = FLASH_READ_ARRAY;
      flashReadState = FLASH_READ_ARRAY;
      break;
    case FLASH_SETBANK:
      if(address == 0)
        {
          flashBank = (byte & 1);
        }
      flashState = FLASH_READ_ARRAY;
      flashReadState = FLASH_READ_ARRAY;
      break;
    }
}