/*-----------------------------------------------------------------------*/
/* MMC/SDC (in SPI mode) control module  (C)ChaN, 2007                   */
/*-----------------------------------------------------------------------*/
/* 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	(0x40+0)	/* GO_IDLE_STATE */
#define CMD1	(0x40+1)	/* SEND_OP_COND */
#define CMD8	(0x40+8)	/* SEND_IF_COND */
#define CMD9	(0x40+9)	/* SEND_CSD */
#define CMD10	(0x40+10)	/* SEND_CID */
#define CMD12	(0x40+12)	/* STOP_TRANSMISSION */
#define CMD16	(0x40+16)	/* SET_BLOCKLEN */
#define CMD17	(0x40+17)	/* READ_SINGLE_BLOCK */
#define CMD18	(0x40+18)	/* READ_MULTIPLE_BLOCK */
#define CMD23	(0x40+23)	/* SET_BLOCK_COUNT */
#define CMD24	(0x40+24)	/* WRITE_BLOCK */
#define CMD25	(0x40+25)	/* WRITE_MULTIPLE_BLOCK */
#define CMD41	(0x40+41)	/* SEND_OP_COND (ACMD) */
#define CMD55	(0x40+55)	/* APP_CMD */
#define CMD58	(0x40+58)	/* READ_OCR */


/* Port Controls  (Platform dependent) */
#define SELECT()	PORTB &= ~1		/* MMC CS = L */
#define	DESELECT()	PORTB |= 1		/* MMC CS = H */

#define SOCKPORT	PINB			/* Socket contact port */
#define SOCKWP		0x20			/* Write protect switch (PB5) */
#define SOCKINS		0x10			/* Card detect switch (PB4) */



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

   Module Private Functions

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

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

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

static
BYTE CardType;			/* b0:MMC, b1:SDC, b2:Block addressing */



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

#define xmit_spi(dat) 	SPDR=(dat); loop_until_bit_is_set(SPSR,SPIF)



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

static
BYTE rcvr_spi (void)
{
	SPDR = 0xFF;
	loop_until_bit_is_set(SPSR, SPIF);
	return SPDR;
}

/* Alternative macro to receive data fast */
#define rcvr_spi_m(dst)	SPDR=0xFF; loop_until_bit_is_set(SPSR,SPIF); *(dst)=SPDR



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

static
BYTE wait_ready (void)
{
	BYTE res;


	Timer2 = 50;	/* Wait for ready in timeout of 500ms */
	rcvr_spi();
	do
		res = rcvr_spi();
	while ((res != 0xFF) && Timer2);

	return res;
}



/*-----------------------------------------------------------------------*/
/* 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
void power_on (void)
{
	PORTE &= ~0x80;				/* Socket power ON */
	for (Timer1 = 3; Timer1; );	/* Wait for 30ms */
	PORTB = 0b10110101;			/* Enable drivers */
	DDRB  = 0b11000111;
	SPCR = 0b01010000;			/* Initialize SPI port (Mode 0) */
	SPSR = 0b00000001;
}

static
void power_off (void)
{
	SELECT();				/* Wait for card ready */
	wait_ready();
	DESELECT();
	rcvr_spi();

	SPCR = 0;				/* Disable SPI function */
	DDRB  = 0b11000000;		/* Disable drivers */
	PORTB = 0b10110000;
	PORTE |=  0x80;			/* Socket power OFF */
	Stat |= STA_NOINIT;		/* Set STA_NOINIT */
}

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



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

static
BOOL rcvr_datablock (
	BYTE *buff,			/* Data buffer to store received data */
	UINT btr			/* Byte count (must be even number) */
)
{
	BYTE token;


	Timer1 = 10;
	do {							/* Wait for data packet in timeout of 100ms */
		token = rcvr_spi();
	} while ((token == 0xFF) && Timer1);
	if(token != 0xFE) return FALSE;	/* If not valid data token, retutn with error */

	do {							/* Receive the data block into buffer */
		rcvr_spi_m(buff++);
		rcvr_spi_m(buff++);
	} while (btr -= 2);
	rcvr_spi();						/* Discard CRC */
	rcvr_spi();

	return TRUE;					/* Return with success */
}



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

#if _READONLY == 0
static
BOOL xmit_datablock (
	const BYTE *buff,	/* 512 byte data block to be transmitted */
	BYTE token			/* Data/Stop token */
)
{
	BYTE resp, wc;


	if (wait_ready() != 0xFF) return FALSE;

	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 FALSE;
	}

	return TRUE;
}
#endif /* _READONLY */



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

static
BYTE send_cmd (
	BYTE cmd,		/* Command byte */
	DWORD arg		/* Argument */
)
{
	BYTE n, res;


	if (wait_ready() != 0xFF) return 0xFF;

	/* Send command packet */
	xmit_spi(cmd);						/* Command */
	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 = 0;
	if (cmd == CMD0) n = 0x95;			/* CRC for CMD0(0) */
	if (cmd == CMD8) n = 0x87;			/* 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 nmuber (0) */
)
{
	BYTE n, 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 */
	for (n = 10; n; n--) rcvr_spi();	/* 80 dummy clocks */

	SELECT();				/* CS = L */
	ty = 0;
	if (send_cmd(CMD0, 0) == 1) {			/* Enter Idle state */
		Timer1 = 100;						/* Initialization timeout of 1000 msec */
		if (send_cmd(CMD8, 0x1AA) == 1) {	/* SDC Ver2+ */
			for (n = 0; n < 4; n++) ocr[n] = rcvr_spi();
			if (ocr[2] == 0x01 && ocr[3] == 0xAA) {	/* The card can work at vdd range of 2.7-3.6V */
				do {