///////////////////////////////////////////////////////////////
//
// VisualDSP++ 4.0 "Flash Programmer" flash driver for use to
// programm the STMicro. M25P64 SPI flash device.
// M25P64 -- 64Mbit ( 8M x 8 )
// 128 (sectors) x 256 (pages) x 256 (bytes)
// 
///////////////////////////////////////////////////////////////

// error enum
#include "Errors.h"
#include <cdefBF533.h>
#include <stdio.h>

// #defines
#define TRUE			0x1
#define FALSE			0x0
// #define NULL			0x0
#define BUFFER_SIZE		0x600
#define	NUM_SECTORS 	128		// number of sectors in the M25P20 flash device

//Application definitions
#define COMMON_SPI_SETTINGS (SPE|MSTR|CPHA|CPOL) //Settings to the SPI_CTL
#define TIMOD01 (0x01)		//stes the SPI to work with core instructions
#define BAUD_RATE_DIVISOR 200

//Flash commands
#define SPI_WREN            (0x06)  //Set Write Enable Latch
#define SPI_WRDI            (0x04)  //Reset Write Enable Latch
#define SPI_RDSR            (0x05)  //Read Status Register
#define SPI_WRSR            (0x01)  //Write Status Register
#define SPI_READ            (0x03)  //Read data from memory
#define SPI_PP              (0x02)  //Program Data into memory
#define SPI_SE              (0xD8)  //Erase one sector in memory
#define SPI_BE              (0xC7)  //Erase all memory
#define WIP					(0x1)	//Check the write in progress bit of the SPI status register
#define WEL					(0x2)	//Check the write enable bit of the SPI status register

#define TIMEOUT        35000*64

// structure for flash sector information
// for the purpose of erase single sectors of the SPI flash the right sector must be chosen
typedef struct _SECTORLOCATION
{
	long lStartOff;
	long lEndOff;
	
}SECTORLOCATION;


// Flash Programmer commands
// The VisualDSP++ flash progammer plug-in "Flash Programmer Tool" will send commands
// to this driver. These commands will be taken to execute the corresponding C function
// The commands are used at the switch case below.
typedef enum
{
	NO_COMMAND,		// 0
	GET_CODES,		// 1
	RESET,			// 2
	WRITE,			// 3
	FILL,			// 4
	ERASE_ALL,		// 5
	ERASE_SECT,		// 6
	READ,			// 7
	GET_SECTNUM,	// 8
}enProgCmds;




// function prototypes
ERROR_CODE SetupForFlash();
ERROR_CODE GetCodes();
ERROR_CODE Wait_For_Status(char Statusbit);
ERROR_CODE Wait_For_WEL();
ERROR_CODE ResetFlash();
ERROR_CODE EraseFlash();
ERROR_CODE EraseBlock( int nBlock );
ERROR_CODE FillData( unsigned long ulStart, long lCount, long lStride, int *pnData );
ERROR_CODE ReadData(  unsigned long ulStart, long lCount, long lStride, int *pnData  );
ERROR_CODE WriteData( unsigned long ulStart, long lCount, long lStride, int *pnData );
ERROR_CODE GetSectorNumber( unsigned long ulOffset, int *pnSector );
ERROR_CODE WriteFlash ( unsigned long StartAddr, long Count, long Stride, int *pnData, long *pnWriteCount );

char ReadStatusRegister(void);
void Wait_For_SPIF(void);
void SetupSPI( const int spi_setting );
void SPI_OFF(void);
void SendSingleCommand( const int iCommand );


// global data for use with the VisualDSP++ plug-in
// The plug-in will modify some AFP variables to control this driver
char 			*AFP_Title = "ADSP-BF533 STAMP";	// This title will be displayed in the plug-in
char 			*AFP_Description = "STMicro. M25P64";	// The description will also be displayed in the plug-in
enProgCmds 		AFP_Command = NO_COMMAND;				// AFP_Command is dedicated to control programm flow
int 			AFP_ManCode = 0x20;						// Some devices have Manufacturer codes to autodetect the device
int 			AFP_DevCode = 0x20;						// Some devices have device codes to autodetect the device
unsigned long 	AFP_Offset = 0;							// AFP_Offset holds the start address to the SPI device
int 			*AFP_Buffer;							// The plug-in copies the content of the *.ldr file to the buffer in small portions
long 			AFP_Size = BUFFER_SIZE;					// The AFP_Buffer size can be modified to change the size
long 			AFP_Count = -1;							// The plug-in copies the number of transfers to be executed to the AFP_Count 
long 			AFP_Stride = -1;						// For the plug-in Fill function a stride can optionally be inserted
int 			AFP_NumSectors = NUM_SECTORS;			// The number of SPI sectors are given for sector erase function
long 			AFP_SectorSize1 = 0x10000;				// The multiplier factor from sector to sector must be given
int 			AFP_Sector = -1;						// In case of sector erase the right sector must be chosen and hold in here
int 			AFP_Error 			= 0;				// contains last error encountered
bool 			AFP_Verify 			= FALSE;			// verify writes or not
long 			AFP_StartOff 		= 0x0;				// sector start offset
long 			AFP_EndOff 			= 0x0;				// sector end offset
int				AFP_FlashWidth		= 0x8;				// width of the flash device taken
int 			*AFP_SectorInfo;
SECTORLOCATION SectorInfo[NUM_SECTORS];


// exit flag
bool bExit = FALSE;


main()
{
	int i = 0;
	// by making AFP_Buffer as big as possible the plug-in can send and
	// receive more data at a time making the data transfer quicker
	//
	// by allocating it on the heap the compiler does not create an
	// initialized array therefore making the driver image smaller
	// and faster to load
	//
	// we have modified the linker description file (LDF) so that the heap
	// is large enough to store BUFFER_SIZE elements at this point
	
	// The AFP_Buffer gets filled by the programmer plug-in. The data the plug-in fetches
	// from the *.ldr file will be stored in the AFP_Buffer byte wise to avoid gaps in the buffer.
	// The verify command uses the buffer to store the data read from the SPI flash for comparison.
	// The fill command uses the first address of the buffer to hold the value to be filled.
	
	// -In case of loading the code to the SPI flash the plug-in will fill the buffer automatically 
	//  so that this driver just has to fetch the data from the buffer and tranfer it to the SPI flash.
	// -In case of reading the data from the SPI flash (plug-in command "VERIFY") this driver just has 
	//  to fetch the data from the SPI flash and store it in the buffer.
	AFP_Buffer = (int *)malloc(BUFFER_SIZE);

	// AFP_Buffer will be NULL if we could not allocate storage for the
	// buffer
	if ( AFP_Buffer == NULL )
	{
		// tell GUI that our buffer was not initialized
		AFP_Error = BUFFER_IS_NULL;
	}



	AFP_SectorInfo = (int*)&SectorInfo[0];
	
	
	for(i=0;i<NUM_SECTORS;i++){

	// This is the sector table of the STMicro. M25P64 SPI flash device.
			SectorInfo[i].lStartOff = 0x0000 + i* 0x10000;
			SectorInfo[i].lEndOff 	= 0xFFFF + i* 0x10000;
	}

	// The while loop below is inserted to give the programmer plug-in control over this driver

	// the plug-in will set a breakpoint at "AFP_BreakReady" forcing the processor to stop.
	// After the plug-in starts the processor again the function which is selected by AFP_Command will be executed.
	// After execution the function the processor stops again at the breadpoint at "AFP_BreakReady".
	// Now the plug-in can place the next command in AFP_Command and start the processor again. 

	while ( !bExit )
	{
		asm("AFP_BreakReady:");
				
		if ( FALSE )
			asm("jump AFP_BreakReady;");

		// switch on the command
		switch ( AFP_Command )
		{
			// As the plug-in displays manufacturer and device ID this function will fetch it from the SPI flash
			// The STMicro. M25P64 SPI flash device does not have those IDs so the function is empty.
			case GET_CODES:
				AFP_Error = GetCodes();
				break;

			// The plug-in offers to reset the flash. This function will send a "write disable command to the SPI flash.
			//  Additionally, it checks the status register for the write enable bit "WEL" to be cleared.
			case RESET:
				AFP_Error = ResetFlash();
				break;

			// By taking the parameters below the function "WriteData" will program the flash.
			// AFP_Offset points to the SPI destination address, AFP_Count holds the number of transfers
			// AFP_Stride holds the address increment and finally AFP_Buffer points to the source buffer.
			case WRITE:
				AFP_Error = WriteData( AFP_Offset, AFP_Count, AFP_Stride, AFP_Buffer );
				break;

			// As the programmer plug-in allows to simply fill the SPI flash with any value the 
			// "FILL" function includes the code. The AFP_Offset points to the destination while the AFP_Count 
			// holds the number of locations where the value will be placed. AFP_Stride holds the increment
			// while AFP_Buffer points to the memory source.
			case FILL:
				AFP_Error = FillData( AFP_Offset, AFP_Count, AFP_Stride, AFP_Buffer );
				break;

			// Pushing the "Erase" button on the programmer plug-in the driver executes an erase all command.
			case ERASE_ALL:
				AFP_Error = EraseFlash();
				break;

			// Pushing the "Erase Sectors" button on the programmer plug-in makes the driver to take the value from
			// AFP_Sector and sends the erase sector command followed by the start address of the dedicated sector.
			// The AFP_Sector gets filled by running the function GET_SECTNUM driven by the plug-in
			case ERASE_SECT:
				AFP_Error = EraseBlock( AFP_Sector );
				break;

			// In order to verify the data that has been programmed to the flash the data must been read.
			// This function will be entered when pushing the Verify button.
			case READ:
				AFP_Error = ReadData( AFP_Offset, AFP_Count, AFP_Stride, AFP_Buffer );
				break;

			// Based on the address where to start programming this sector must be erased before. 
			// The function GET_SECTNUM will return the sector number where the start address points to.
			// The sector number will than be taken to run the EraseBlock function.
			case GET_SECTNUM:
				AFP_Error = GetSectorNumber( AFP_Offset, &AFP_Sector );
				break;

			// no command or unknown command do nothing
			case NO_COMMAND:
			default:
				// set our error
				AFP_Error = UNKNOWN_COMMAND;
				break;
		}

		// clear the command
		AFP_Command = NO_COMMAND;
	}

	// free the buffer if we were able to allocate one
	if ( AFP_Buffer )
		free( AFP_Buffer );


	// all done
	return 0;
}



//////////////////////////////////////////////////////////////
// ERROR_CODE WriteData()
//
// Write the contents of AFP_Buffer to SPI flash.
//
// Inputs:	unsigned long ulStart - SPI start address 
//			long lCount - number of elements write to the SPI
//			long lStride - address increment to the SPI
//			int *pnData - pointer to data buffer
//
// This function takes the input parameters and calls the function 
// WriteFlash which writes the data of AFP_Buffer to the SPI.
//
// The function WriteFlash will usually be executed multiple times because 
// the SPI needs a break after a transfer of max. 256 bytes for programming
// each following transfer will need recalculated addresses and counts
//////////////////////////////////////////////////////////////

ERROR_CODE WriteData( unsigned long ulStart, long lCount, long lStride, int *pnData )
{

	unsigned long ulWStart = ulStart; 
	long lWCount = lCount, lWriteCount;
	long *pnWriteCount = &lWriteCount;
	int i;
	
	
	ERROR_CODE ErrorCode = NO_ERR;

	while (lWCount != 0)
	{
		ErrorCode = WriteFlash(ulWStart, lWCount, lStride, pnData, pnWriteCount);
		
		// After each function call of WriteFlash the counter must be adjusted
		lWCount -= *pnWriteCount;
		
		// Also, both address pointers must be recalculated.
		ulWStart += *pnWriteCount;
		pnData += *pnWriteCount/4;
	}

	for(i=0; i<1000; i++)
	{
		asm("nop;");
	}

	
	// return the appropriate error code
	return ErrorCode;
	
}


//////////////////////////////////////////////////////////////
// ERROR_CODE FillData()
//
// Fill flash with a value.
//
// Inputs:	unsigned long ulStart - offset in flash to start the writes at
//			long lCount - number of elements to write, in this case bytes
//			long lStride - number of locations to skip between writes
//			int *pnData - pointer to data buffer
//
//////////////////////////////////////////////////////////////

ERROR_CODE FillData( unsigned long ulStart, long lCount, long lStride, int *pnData )
{

	
	unsigned long ulWAddr = ulStart; 
	long lWCount = 1, lWriteCount;
	long *pnWriteCount = &lWriteCount;

	int i;
	ERROR_CODE ErrorCode = NO_ERR;	// tells us if there was an error erasing flash

	
    for (i = 0; i < lCount; i++, ulWAddr += lStride)
	{
		ErrorCode = WriteFlash(ulWAddr, lWCount, lStride, pnData, pnWriteCount);
	}
	
	
	for(i=0; i<1000; i++)
	{
		asm("nop;");
	}
	
	// return the appropriate error code
	return ErrorCode;
	
}



//////////////////////////////////////////////////////////////
// ERROR_CODE WriteFlash()
//
// Write the maximum of 256 bytes to flash.
//
// Inputs:	unsigned long StartAddr - address to write to
//			int iDataSource - pointer to the AFP_Buffer
//			long lTransferCount - number of elements to send
//////////////////////////////////////////////////////////////

ERROR_CODE WriteFlash ( unsigned long ulStartAddr, long lTransferCount, long lModify, int *iDataSource, long *lWriteCount )
{

	unsigned long ulWAddr;
	long lWTransferCount = 0;
	int i;
	char iData;
	char *temp = (char *)iDataSource;
	int dummyread;
	ERROR_CODE ErrorCode = NO_ERR;	// tells us if there was an error erasing flash

	// First, a Write Enable Command must be sent to the SPI.
	SendSingleCommand(SPI_WREN);
	
	// Second, the SPI Status Register will be tested whether the 
	//         Write Enable Bit has been set. 
	ErrorCode = Wait_For_WEL();

	if( POLL_TIMEOUT == ErrorCode )
		return ErrorCode;
	else

	// Third, the 24 bit address will be shifted out the SPI MOSI bytewise.
	SetupSPI( (COMMON_SPI_SETTINGS|TIMOD01) ); // Turns the SPI on

	*pSPI_TDBR = SPI_PP;
	Wait_For_SPIF();		//wait until the instruction has been sent
	ulWAddr = (ulStartAddr >> 16);
	*pSPI_TDBR = ulWAddr;
	Wait_For_SPIF();		//wait until the instruction has been sent
	ulWAddr = (ulStartAddr >> 8);
	*pSPI_TDBR = ulWAddr;
	Wait_For_SPIF();		//wait until the instruction has been sent
	ulWAddr = ulStartAddr;
	*pSPI_TDBR = ulWAddr;
	Wait_For_SPIF();		//wait until the instruction has been sent
	dummyread = *pSPI_RDBR;	//read dummy to empty the receive register

	
	// Fourth, maximum number of 256 bytes will be taken from the Buffer
	// and sent to the SPI device.
	for (i=0; (i < lTransferCount) && (i < 256); i++, lWTransferCount++)
	{
		iData = *temp;
		*pSPI_TDBR = iData;
		Wait_For_SPIF();		//wait until the instruction has been sent

		((unsigned char *) temp) ++;
	}
		
	SPI_OFF(); // Turns the SPI off

	// Sixth, the SPI Write in Progress Bit must be toggled to ensure the 
	// programming is done before start of next transfer.
	ErrorCode = Wait_For_Status(WIP);
	
	if( POLL_TIMEOUT == ErrorCode )
		return ErrorCode;
	else


	
	*lWriteCount = lWTransferCount;
	
	return ErrorCode;
}

//////////////////////////////////////////////////////////////
// ERROR_CODE ReadData()
//
// Read a value from flash for verify purpose
//
// Inputs:	unsigned long ulStart - holds the SPI start address
//			int pnData - pointer to store value read from flash
//			long lCount - number of elements to read