/*-----------------------------------------------------------------------*/
/* MMCv3/SDv1/SDv2 (in SPI mode) control module  (C)ChaN, 2012           */
/*-----------------------------------------------------------------------*/

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


/* Port controls  (Platform dependent) */

#define CS_LOW()	{SD_CS_PORT &= ~SD_CS; LEDR_ON();}	/* CS=low, LED on */
#define	CS_HIGH()	{SD_CS_PORT |= SD_CS; LEDR_OFF();}	/* CS=high, LED off */
#define POWER_ON()	{SD_PWROFF_PORT &= ~SD_PWROFF;}	/* MMC power on */
#define POWER_OFF()	{SD_PWROFF_PORT |= SD_PWROFF;}		/* MMC power off */
#define POWER		(!(SD_PWROFF_PIN & SD_PWROFF))	/* Test for power state.   on:true, off:false */
#define SOCKINS		(!(SD_CD_PIN & SD_CD))	/* Test for card exist.    yes:true, true:false, default:true */
#define SOCKWP		(SD_WP_PIN & SD_WP)		/* Test for write protect. yes:true, no:false, default:false */
#define	FCLK_SLOW()	SPCR = _BV(MSTR) | _BV(SPE) | _BV(SPR1) | _BV(SPR0)	/* Set slow clock (F_CPU / 64) */
#define	FCLK_FAST()	SPCR = _BV(MSTR) | _BV(SPE)							/* Set fast clock (F_CPU / 2) */


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

   Module Private Functions

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

/* 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 */


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

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

static
BYTE CardType;			/* Card type flags */


/*-----------------------------------------------------------------------*/
/* 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_off (void)
{
	SPCR = 0;				/* Disable SPI function */

	DDRB  &= ~(_BV(PB5) | _BV(PB7));	/* Set SCK/MOSI to hi-z */
	SD_CS_DDR &= ~SD_CS;
	POWER_OFF();
	Stat |= STA_NOINIT;
}

static
void power_on (void)	/* Apply power sequence */
{
	SD_PWROFF_DDR |= SD_PWROFF;
	for (Timer1 = 30; Timer1; ) {};	/* 300ms */
	POWER_ON();						/* Power on */
	for (Timer1 = 3; Timer1; ) {};	/* 30ms */

	SD_CS_PORT |= SD_CS;
	SD_CS_DDR |= SD_CS;

	PORTB |= _BV(PB5) | _BV(PB7);	/* Configure SCK/MOSI as output */
	DDRB  |= _BV(PB5) | _BV(PB7);

	FCLK_SLOW();	/* Enable SPI function in mode 0 */
	SPSR = _BV(SPI2X);	/* SPI 2x mode */
}



/*-----------------------------------------------------------------------*/
/* Transmit/Receive data from/to MMC via SPI  (Platform dependent)       */
/*-----------------------------------------------------------------------*/

/* Exchange a byte */
static
BYTE xchg_spi (		/* Returns received data */
	BYTE dat		/* Data to be sent */
)
{
	SPDR = dat;
	loop_until_bit_is_set(SPSR, SPIF);
	return SPDR;
}

/* Send a data block */
static
void xmit_spi_multi (
	const BYTE *p,	/* Data block to be sent */
	UINT cnt		/* Size of data block */
)
{
	do {
		SPDR = *p++; loop_until_bit_is_set(SPSR,SPIF);
		SPDR = *p++; loop_until_bit_is_set(SPSR,SPIF);
	} while (cnt -= 2);
}

/* Receive a data block */
static
void rcvr_spi_multi (
	BYTE *p,	/* Data buffer */
	UINT cnt	/* Size of data block */
)
{
	do {
		SPDR = 0xFF; loop_until_bit_is_set(SPSR,SPIF); *p++ = SPDR;
		SPDR = 0xFF; loop_until_bit_is_set(SPSR,SPIF); *p++ = SPDR;
	} while (cnt -= 2);
}



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

static
int wait_ready (void)	/* 1:OK, 0:Timeout */
{
	BYTE d;


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

	return (d == 0xFF) ? 1 : 0;
}



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

static
void deselect (void)
{
	CS_HIGH();
	xchg_spi(0xFF);	/* Dummy clock (force DO hi-z for multiple slave SPI) */
}



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

static
int select (void)	/* 1:Successful, 0:Timeout */
{
	CS_LOW();
	xchg_spi(0xFF);	/* Dummy clock (force DO enabled) */

	if (wait_ready()) return 1;	/* OK */
	deselect();
	return 0;	/* Timeout */
}



/*-----------------------------------------------------------------------*/
/* 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 = xchg_spi(0xFF);
	} while ((token == 0xFF) && Timer1);
	if (token != 0xFE) return 0;	/* If not valid data token, retutn with error */

	rcvr_spi_multi(buff, btr);		/* Receive the data block into buffer */
	xchg_spi(0xFF);					/* Discard CRC */
	xchg_spi(0xFF);

	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;


	if (!wait_ready()) return 0;

	xchg_spi(token);					/* Xmit data token */
	if (token != 0xFD) {	/* Is data token */
		xmit_spi_multi(buff, 512);		/* Xmit the data block to the MMC */
		xchg_spi(0xFF);					/* CRC (Dummy) */
		xchg_spi(0xFF);
		resp = xchg_spi(0xFF);			/* 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 */
	xchg_spi(0x40 | cmd);				/* Start + Command index */
	xchg_spi((BYTE)(arg >> 24));		/* Argument[31..24] */
	xchg_spi((BYTE)(arg >> 16));		/* Argument[23..16] */
	xchg_spi((BYTE)(arg >> 8));			/* Argument[15..8] */
	xchg_spi((BYTE)arg);				/* Argument[7..0] */
	n = 0x01;							/* Dummy CRC + Stop */
	if (cmd == CMD0) n = 0x95;			/* Valid CRC for CMD0(0) + Stop */
	if (cmd == CMD8) n = 0x87;			/* Valid CRC for CMD8(0x1AA) Stop */
	xchg_spi(n);

	/* Receive command response */
	if (cmd == CMD12) xchg_spi(0xFF);		/* Skip a stuff byte when stop reading */
	n = 10;								/* Wait for a valid response in timeout of 10 attempts */
	do
		res = xchg_spi(0xFF);
	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, cmd, ty, ocr[4];


	if (drv) return STA_NOINIT;			/* Supports only single drive */
	power_off();						/* Turn off the socket power to reset the card */
	if (Stat & STA_NODISK) return Stat;	/* No card in the socket */
	power_on();							/* Turn on the socket power */
	FCLK_SLOW();
	for (n = 10; n; n--) xchg_spi(0xFF);	/* 80 dummy clocks */

	ty = 0;
	if (send_cmd(CMD0, 0) == 1) {			/* Enter Idle state */
		Timer1 = 100;						/* Initialization timeout of 1000 msec */
		if (send_cmd(CMD8, 0x1AA) == 1) {	/* SDv2? */
			for (n = 0; n < 4; n++) ocr[n] = xchg_spi(0xFF);		/* Get trailing return value of R7 resp */
			if (ocr[2] == 0x01 && ocr[3] == 0xAA) {				/* 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] = xchg_spi(0xFF);
					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 | STA_NODISK;		/* 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) */
	UINT 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) */
	UINT 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 __attribute((unused))	/* Buffer to send/receive control data */
)
{
	DRESULT res;


	if (drv) return RES_PARERR;
	buff = 0;

	if (ctrl == CTRL_POWER) {
		power_off();
		return RES_OK;
	}

	if (Stat & STA_NOINIT) return RES_NOTRDY;

	res = RES_ERROR;
	switch (ctrl) {
	case CTRL_SYNC :
		if (select()) {
			deselect();
			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;				/* Update MMC status */
}
