/*-----------------------------------------------------------------------*/
/* MMCv3/SDv1/SDv2 (in SPI mode) control module  (C)ChaN, 2010           */
/*-----------------------------------------------------------------------*/
/* Only rcvr_spi(), xmit_spi(), disk_timerproc() and some macros         */
/* are platform dependent.                                               */
/*-----------------------------------------------------------------------*/


#include <avr/io.h>
#include "diskio.h"


/* Definitions for MMC/SDC command */
#define CMD0	(0)			/* GO_IDLE_STATE */
#define CMD1	(1)			/* SEND_OP_COND (MMC) */
#define	ACMD41	(0x80+41)	/* SEND_OP_COND (SDC) */
#define CMD8	(8)			/* SEND_IF_COND */
#define CMD9	(9)			/* SEND_CSD */
#define CMD10	(10)		/* SEND_CID */
#define CMD12	(12)		/* STOP_TRANSMISSION */
#define ACMD13	(0x80+13)	/* SD_STATUS (SDC) */
#define CMD16	(16)		/* SET_BLOCKLEN */
#define CMD17	(17)		/* READ_SINGLE_BLOCK */
#define CMD18	(18)		/* READ_MULTIPLE_BLOCK */
#define CMD23	(23)		/* SET_BLOCK_COUNT (MMC) */
#define	ACMD23	(0x80+23)	/* SET_WR_BLK_ERASE_COUNT (SDC) */
#define CMD24	(24)		/* WRITE_BLOCK */
#define CMD25	(25)		/* WRITE_MULTIPLE_BLOCK */
#define CMD55	(55)		/* APP_CMD */
#define CMD58	(58)		/* READ_OCR */

/* Card type flags (CardType) */
#define CT_MMC		0x01		/* MMC ver 3 */
#define CT_SD1		0x02		/* SD ver 1 */
#define CT_SD2		0x04		/* SD ver 2 */
#define CT_SDC		(CT_SD1|CT_SD2)	/* SD */
#define CT_BLOCK	0x08		/* Block addressing */

/* Port Controls  (Platform dependent) */
#define CS_LOW()	PORTE.OUTCLR = 0x10		/* MMC CS = L */
#define	CS_HIGH()	PORTE.OUTSET = 0x10		/* MMC CS = H */

//#define SOCKPORT	PORTE			/* Socket contact port */
#define SOCKWP		0			/* Write protect switch (PB5) */
#define SOCKINS		((~(PORTE.IN)) & 0x08)			/* Card detect switch (PD3) */

#define	FCLK_SLOW()	SPIE.CTRL = SPI_ENABLE_bm | SPI_MASTER_bm | SPI_MODE_0_gc | SPI_PRESCALER_DIV128_gc;	/* Set slow clock (100k-400k) */
#define	FCLK_FAST()	SPIE.CTRL = SPI_ENABLE_bm | SPI_MASTER_bm | SPI_MODE_0_gc | SPI_PRESCALER_DIV4_gc;  /* Set fast clock (depends on the CSD) */

DWORD get_fattime ()
{
    return 0;
}
/*--------------------------------------------------------------------------

   Module Private Functions

---------------------------------------------------------------------------*/

static volatile
DSTATUS Stat = STA_NOINIT;	/* Disk status */

static volatile
BYTE Timer1, Timer2;	/* 100Hz decrement timer */

static
BYTE CardType;			/* Card type flags */


/*-----------------------------------------------------------------------*/
/* Transmit a byte to MMC via SPI  (Platform dependent)                  */
/*-----------------------------------------------------------------------*/

#define xmit_spi(dat) 	SPIE.DATA=(dat); loop_until_bit_is_set(SPIE.STATUS,SPI_IF_bp)



/*-----------------------------------------------------------------------*/
/* Receive a byte from MMC via SPI  (Platform dependent)                 */
/*-----------------------------------------------------------------------*/

static
BYTE rcvr_spi (void)
{
	SPIE.DATA = 0xFF;
	loop_until_bit_is_set(SPIE.STATUS, SPI_IF_bp);
	return SPIE.DATA;
}

/* Alternative macro to receive data fast */
#define rcvr_spi_m(dst)	SPIE.DATA=0xFF; loop_until_bit_is_set(SPIE.STATUS, SPI_IF_bp); *(dst)=SPIE.DATA



/*-----------------------------------------------------------------------*/
/* Wait for card ready                                                   */
/*-----------------------------------------------------------------------*/

static
int wait_ready (void)	/* 1:OK, 0:Timeout */
{
	Timer2 = 50;	/* Wait for ready in timeout of 500ms */
	rcvr_spi();
	do
		if (rcvr_spi() == 0xFF) return 1;
	while (Timer2);

	return 0;
}



/*-----------------------------------------------------------------------*/
/* Deselect the card and release SPI bus                                 */
/*-----------------------------------------------------------------------*/

static
void deselect (void)
{
	CS_HIGH();
	rcvr_spi();
}



/*-----------------------------------------------------------------------*/
/* Select the card and wait for ready                                    */
/*-----------------------------------------------------------------------*/

static
int select (void)	/* 1:Successful, 0:Timeout */
{
	CS_LOW();
	if (!wait_ready()) {
		deselect();
		return 0;
	}
	return 1;
}



/*-----------------------------------------------------------------------*/
/* Power Control  (Platform dependent)                                   */
/*-----------------------------------------------------------------------*/
/* When the target system does not support socket power control, there   */
/* is nothing to do in these functions and chk_power always returns 1.   */

static
int power_status(void)		/* Socket power state: 0=off, 1=on */
{
	//return (PORTE & 0x80) ? 0 : 1;
	return 1;//always power on
}


static
void power_on (void)
{
/*	//no power on or off available
    PORTE &= ~0x80;				// Socket power on
	for (Timer1 = 2; Timer1; );	// Wait for 20ms
	PORTB = 0b10110101;			// Enable drivers
	DDRB  = 0b11000111;
*/
    //PORTE.PIN0CTRL |= PORT_OPC_PULLUP_gc; //place pullup on pin7, used as 'write protect'
    PORTE.DIR = 0b10110000;
    PORTE.OUT = 0b10110000;
	SPIE.CTRL = SPI_ENABLE_bm | SPI_MASTER_bm | SPI_MODE_0_gc | SPI_PRESCALER_DIV128_gc;
	//SPCR = 0x52;			/* Enable SPI function in mode 0 */
	//SPSR = 0x01;			/* SPI 2x mode */
}


static
void power_off (void)
{
	SPIE.CTRL = 0;				/* Disable SPI function */
	/*
	// no power on or off available
	DDRB  = 0b11000000;		 Disable drivers
	PORTB = 0b10110000;

	PORTE |=  0x80;			 Socket power off
	*/
    PORTE.DIR = 0b10000000;
    PORTE.OUT = 0b10000000;

	Stat |= STA_NOINIT;
}



/*-----------------------------------------------------------------------*/
/* Receive a data packet from MMC                                        */
/*-----------------------------------------------------------------------*/

static
int rcvr_datablock (
	BYTE *buff,			/* Data buffer to store received data */
	UINT btr			/* Byte count (must be multiple of 4) */
)
{
	BYTE token;


	Timer1 = 20;
	do {							/* Wait for data packet in timeout of 200ms */
		token = rcvr_spi();
	} while ((token == 0xFF) && Timer1);
	if(token != 0xFE) return 0;		/* If not valid data token, retutn with error */

	do {							/* Receive the data block into buffer */
		rcvr_spi_m(buff++);
		rcvr_spi_m(buff++);
		rcvr_spi_m(buff++);
		rcvr_spi_m(buff++);
	} while (btr -= 4);
	rcvr_spi();						/* Discard CRC */
	rcvr_spi();

	return 1;						/* Return with success */
}



/*-----------------------------------------------------------------------*/
/* Send a data packet to MMC                                             */
/*-----------------------------------------------------------------------*/

static
int xmit_datablock (
	const BYTE *buff,	/* 512 byte data block to be transmitted */
	BYTE token			/* Data/Stop token */
)
{
	BYTE resp, wc;


	if (!wait_ready()) return 0;

	xmit_spi(token);					/* Xmit data token */
	if (token != 0xFD) {	/* Is data token */
		wc = 0;
		do {							/* Xmit the 512 byte data block to MMC */
			xmit_spi(*buff++);
			xmit_spi(*buff++);
		} while (--wc);
		xmit_spi(0xFF);					/* CRC (Dummy) */
		xmit_spi(0xFF);
		resp = rcvr_spi();				/* Reveive data response */
		if ((resp & 0x1F) != 0x05)		/* If not accepted, return with error */
			return 0;
	}

	return 1;
}



/*-----------------------------------------------------------------------*/
/* Send a command packet to MMC                                          */
/*-----------------------------------------------------------------------*/

static
BYTE send_cmd (		/* Returns R1 resp (bit7==1:Send failed) */
	BYTE cmd,		/* Command index */
	DWORD arg		/* Argument */
)
{
	BYTE n, res;


	if (cmd & 0x80) {	/* ACMD<n> is the command sequense of CMD55-CMD<n> */
		cmd &= 0x7F;
		res = send_cmd(CMD55, 0);
		if (res > 1) return res;
	}

	/* Select the card and wait for ready */
	deselect();
	if (!select()) return 0xFF;

	/* Send command packet */
	xmit_spi(0x40 | cmd);				/* Start + Command index */
	xmit_spi((BYTE)(arg >> 24));		/* Argument[31..24] */
	xmit_spi((BYTE)(arg >> 16));		/* Argument[23..16] */
	xmit_spi((BYTE)(arg >> 8));			/* Argument[15..8] */
	xmit_spi((BYTE)arg);				/* Argument[7..0] */
	n = 0x01;							/* Dummy CRC + Stop */
	if (cmd == CMD0) n = 0x95;			/* Valid CRC for CMD0(0) */
	if (cmd == CMD8) n = 0x87;			/* Valid CRC for CMD8(0x1AA) */
	xmit_spi(n);

	/* Receive command response */
	if (cmd == CMD12) rcvr_spi();		/* Skip a stuff byte when stop reading */
	n = 10;								/* Wait for a valid response in timeout of 10 attempts */
	do
		res = rcvr_spi();
	while ((res & 0x80) && --n);

	return res;			/* Return with the response value */
}



/*--------------------------------------------------------------------------

   Public Functions

---------------------------------------------------------------------------*/


/*-----------------------------------------------------------------------*/
/* Initialize Disk Drive                                                 */
/*-----------------------------------------------------------------------*/

DSTATUS disk_initialize (
	BYTE drv		/* Physical drive number (0) */
)
{
	BYTE n, cmd, ty, ocr[4];


	if (drv) return STA_NOINIT;			/* Supports only single drive */
	if (Stat & STA_NODISK) return Stat;	/* No card in the socket */

	power_on();							/* Force socket power on */
	FCLK_SLOW();
	for (n = 10; n; n--) rcvr_spi();	/* 80 dummy clocks */

	ty = 0;
	if (send_cmd(CMD0, 0) == 1) {			/* Enter Idle state */
		Timer1 = 250;						/* Initialization timeout of 1000 msec */
		if (send_cmd(CMD8, 0x1AA) == 1) {	/* SDv2? */
			for (n = 0; n < 4; n++) ocr[n] = rcvr_spi();		/* Get trailing return value of R7 resp */
			if (/*ocr[2] == 0x01 && ocr[3] == 0xAA*/1) {				/* The card can work at vdd range of 2.7-3.6V */
				while (Timer1 && send_cmd(ACMD41, 1UL << 30));	/* Wait for leaving idle state (ACMD41 with HCS bit) */
				if (Timer1 && send_cmd(CMD58, 0) == 0) {		/* Check CCS bit in the OCR */
					for (n = 0; n < 4; n++) ocr[n] = rcvr_spi();
					ty = (ocr[0] & 0x40) ? CT_SD2 | CT_BLOCK : CT_SD2;	/* SDv2 */
				}
			}
		} else {							/* SDv1 or MMCv3 */
			if (send_cmd(ACMD41, 0) <= 1) 	{
				ty = CT_SD1; cmd = ACMD41;	/* SDv1 */
			} else {
				ty = CT_MMC; cmd = CMD1;	/* MMCv3 */
			}
			while (Timer1 && send_cmd(cmd, 0));			/* Wait for leaving idle state */
			if (!Timer1 || send_cmd(CMD16, 512) != 0)	/* Set R/W block length to 512 */
				ty = 0;
		}
	}
	CardType = ty;
	deselect();

	if (ty) {			/* Initialization succeded */
		Stat &= ~STA_NOINIT;		/* Clear STA_NOINIT */
		FCLK_FAST();
	} else {			/* Initialization failed */
		power_off();
	}

	return Stat;
}



/*-----------------------------------------------------------------------*/
/* Get Disk Status                                                       */
/*-----------------------------------------------------------------------*/

DSTATUS disk_status (
	BYTE drv		/* Physical drive nmuber (0) */
)
{
	if (drv) return STA_NOINIT;		/* Supports only single drive */
	return Stat;
}



/*-----------------------------------------------------------------------*/
/* Read Sector(s)                                                        */
/*-----------------------------------------------------------------------*/

DRESULT disk_read (
	BYTE drv,			/* Physical drive nmuber (0) */
	BYTE *buff,			/* Pointer to the data buffer to store read data */
	DWORD sector,		/* Start sector number (LBA) */
	BYTE count			/* Sector count (1..255) */
)
{
	if (drv || !count) return RES_PARERR;
	if (Stat & STA_NOINIT) return RES_NOTRDY;

	if (!(CardType & CT_BLOCK)) sector *= 512;	/* Convert to byte address if needed */

	if (count == 1) {	/* Single block read */
		if ((send_cmd(CMD17, sector) == 0)	/* READ_SINGLE_BLOCK */
			&& rcvr_datablock(buff, 512))
			count = 0;
	}
	else {				/* Multiple block read */
		if (send_cmd(CMD18, sector) == 0) {	/* READ_MULTIPLE_BLOCK */
			do {
				if (!rcvr_datablock(buff, 512)) break;
				buff += 512;
			} while (--count);
			send_cmd(CMD12, 0);				/* STOP_TRANSMISSION */
		}
	}
	deselect();

	return count ? RES_ERROR : RES_OK;
}



/*-----------------------------------------------------------------------*/
/* Write Sector(s)                                                       */
/*-----------------------------------------------------------------------*/

DRESULT disk_write (
	BYTE drv,			/* Physical drive nmuber (0) */
	const BYTE *buff,	/* Pointer to the data to be written */
	DWORD sector,		/* Start sector number (LBA) */
	BYTE count			/* Sector count (1..255) */
)
{
	if (drv || !count) return RES_PARERR;
	if (Stat & STA_NOINIT) return RES_NOTRDY;
	if (Stat & STA_PROTECT) return RES_WRPRT;

	if (!(CardType & CT_BLOCK)) sector *= 512;	/* Convert to byte address if needed */

	if (count == 1) {	/* Single block write */
		if ((send_cmd(CMD24, sector) == 0)	/* WRITE_BLOCK */
			&& xmit_datablock(buff, 0xFE))
			count = 0;
	}
	else {				/* Multiple block write */
		if (CardType & CT_SDC) send_cmd(ACMD23, count);
		if (send_cmd(CMD25, sector) == 0) {	/* WRITE_MULTIPLE_BLOCK */
			do {
				if (!xmit_datablock(buff, 0xFC)) break;
				buff += 512;
			} while (--count);
			if (!xmit_datablock(0, 0xFD))	/* STOP_TRAN token */
				count = 1;
		}
	}
	deselect();

	return count ? RES_ERROR : RES_OK;
}



/*-----------------------------------------------------------------------*/
/* Miscellaneous Functions                                               */
/*-----------------------------------------------------------------------*/

DRESULT disk_ioctl (
	BYTE drv,		/* Physical drive nmuber (0) */
	BYTE ctrl,		/* Control code */
	void *buff		/* Buffer to send/receive control data */
)
{
	DRESULT res;
	BYTE n, csd[16], *ptr = buff;
	WORD csize;


	if (drv) return RES_PARERR;

	res = RES_ERROR;

	if (ctrl == CTRL_POWER) {
		switch (ptr[0]) {
		case 0:		/* Sub control code (POWER_OFF) */
			power_off();		/* Power off */
			res = RES_OK;
			break;
		case 1:		/* Sub control code (POWER_GET) */
			ptr[1] = (BYTE)power_status();
			res = RES_OK;
			break;
		default :
			res = RES_PARERR;
		}
	}
	else {
		if (Stat & STA_NOINIT) return RES_NOTRDY;

		switch (ctrl) {
		case CTRL_SYNC :		/* Make sure that no pending write process. Do not remove this or written sector might not left updated. */
			if (select()) {
				deselect();
				res = RES_OK;
			}
			break;

		case GET_SECTOR_COUNT :	/* Get number of sectors on the disk (DWORD) */
			if ((send_cmd(CMD9, 0) == 0) && rcvr_datablock(csd, 16)) {
				if ((csd[0] >> 6) == 1) {	/* SDC ver 2.00 */
					csize = csd[9] + ((WORD)csd[8] << 8) + 1;
					*(DWORD*)buff = (DWORD)csize << 10;
				} else {					/* SDC ver 1.XX or MMC*/
					n = (csd[5] & 15) + ((csd[10] & 128) >> 7) + ((csd[9] & 3) << 1) + 2;
					csize = (csd[8] >> 6) + ((WORD)csd[7] << 2) + ((WORD)(csd[6] & 3) << 10) + 1;
					*(DWORD*)buff = (DWORD)csize << (n - 9);
				}
				res = RES_OK;
			}
			break;

		case GET_SECTOR_SIZE :	/* Get R/W sector size (WORD) */
			*(WORD*)buff = 512;
			res = RES_OK;
			break;

		case GET_BLOCK_SIZE :	/* Get erase block size in unit of sector (DWORD) */
			if (CardType & CT_SD2) {	/* SDv2? */
				if (send_cmd(ACMD13, 0) == 0) {	/* Read SD status */
					rcvr_spi();
					if (rcvr_datablock(csd, 16)) {				/* Read partial block */
						for (n = 64 - 16; n; n--) rcvr_spi();	/* Purge trailing data */
						*(DWORD*)buff = 16UL << (csd[10] >> 4);
						res = RES_OK;
					}
				}
			} else {					/* SDv1 or MMCv3 */
				if ((send_cmd(CMD9, 0) == 0) && rcvr_datablock(csd, 16)) {	/* Read CSD */
					if (CardType & CT_SD1) {	/* SDv1 */
						*(DWORD*)buff = (((csd[10] & 63) << 1) + ((WORD)(csd[11] & 128) >> 7) + 1) << ((csd[13] >> 6) - 1);
					} else {					/* MMCv3 */
						*(DWORD*)buff = ((WORD)((csd[10] & 124) >> 2) + 1) * (((csd[11] & 3) << 3) + ((csd[11] & 224) >> 5) + 1);
					}
					res = RES_OK;
				}
			}
			break;

		case MMC_GET_TYPE :		/* Get card type flags (1 byte) */
			*ptr = CardType;
			res = RES_OK;
			break;

		case MMC_GET_CSD :		/* Receive CSD as a data block (16 bytes) */
			if (send_cmd(CMD9, 0) == 0		/* READ_CSD */
				&& rcvr_datablock(ptr, 16))
				res = RES_OK;
			break;

		case MMC_GET_CID :		/* Receive CID as a data block (16 bytes) */
			if (send_cmd(CMD10, 0) == 0		/* READ_CID */
				&& rcvr_datablock(ptr, 16))
				res = RES_OK;
			break;

		case MMC_GET_OCR :		/* Receive OCR as an R3 resp (4 bytes) */
			if (send_cmd(CMD58, 0) == 0) {	/* READ_OCR */
				for (n = 4; n; n--) *ptr++ = rcvr_spi();
				res = RES_OK;
			}
			break;

		case MMC_GET_SDSTAT :	/* Receive SD statsu as a data block (64 bytes) */
			if (send_cmd(ACMD13, 0) == 0) {	/* SD_STATUS */
				rcvr_spi();
				if (rcvr_datablock(ptr, 64))
					res = RES_OK;
			}
			break;

		default:
			res = RES_PARERR;
		}

		deselect();
	}

	return res;
}



/*-----------------------------------------------------------------------*/
/* Device Timer Interrupt Procedure                                      */
/*-----------------------------------------------------------------------*/
/* This function must be called in period of 10ms                        */

void disk_timerproc (void)
{
	BYTE n, s;


	n = Timer1;						/* 100Hz decrement timer */
	if (n) Timer1 = --n;
	n = Timer2;
	if (n) Timer2 = --n;

	s = Stat;

	if (SOCKWP)				/* Write protected */
		s |= STA_PROTECT;
	else					/* Write enabled */
		s &= ~STA_PROTECT;
	if (SOCKINS)			/* Card inserted */
		s &= ~STA_NODISK;
	else					/* Socket empty */
		s |= (STA_NODISK | STA_NOINIT);

	Stat = s;
}

