mmc.c

这是一个很精巧的FAT文件系统的,它实现数据文件存储的FAT方式访问

/*-----------------------------------------------------------------------*/
/* 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 = 1000;						/* 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 {
					if (send_cmd(CMD55, 0) <= 1 && send_cmd(CMD41, 1UL << 30) == 0) break; /* ACMD41 with HCS bit */
				} while (Timer1);
				if (Timer1 && send_cmd(CMD58, 0) == 0) {	/* Check CCS bit */
					for (n = 0; n < 4; n++) ocr[n] = rcvr_spi();
					ty = (ocr[0] & 0x40) ? 6 : 2;
				}
			}
		} else {							/* SDC Ver1 or MMC */
			ty = (send_cmd(CMD55, 0) <= 1 && send_cmd(CMD41, 0) <= 1) ? 2 : 1;	/* SDC : MMC */
			do {
				if (ty == 2) {
					if (send_cmd(CMD55, 0) <= 1 && send_cmd(CMD41, 0) == 0) break;	/* ACMD41 */
				} else {
					if (send_cmd(CMD1, 0) == 0) break;								/* CMD1 */
				}
			} while (Timer1);
			if (Timer1 == 0 && send_cmd(CMD16, 512) != 0)	/* Select R/W block length */
				ty = 0;
		}
	}
	CardType = ty;
	DESELECT();			/* CS = H */
	rcvr_spi();			/* Idle (Release DO) */

	if (ty) {			/* Initialization succeded */
		Stat &= ~STA_NOINIT;		/* Clear STA_NOINIT */
	} 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 & 4)) sector *= 512;	/* Convert to byte address if needed */

	SELECT();			/* CS = L */

	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();			/* CS = H */
	rcvr_spi();			/* Idle (Release DO) */

	return count ? RES_ERROR : RES_OK;
}



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

#if _READONLY == 0
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 & 4)) sector *= 512;	/* Convert to byte address if needed */

	SELECT();			/* CS = L */

	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 & 2) {
			send_cmd(CMD55, 0); send_cmd(CMD23, count);	/* ACMD23 */
		}
		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();			/* CS = H */
	rcvr_spi();			/* Idle (Release DO) */

	return count ? RES_ERROR : RES_OK;
}
#endif /* _READONLY */



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

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


	if (drv) return RES_PARERR;
	if (Stat & STA_NOINIT) return RES_NOTRDY;

	SELECT();		/* CS = L */

	res = RES_ERROR;
	switch (ctrl) {
		case GET_SECTOR_COUNT :	/* Get number of sectors on the disk (WORD) */
			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 {					/* MMC or SDC ver 1.XX */
					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 sectors on the disk (WORD) */
			*(WORD*)buff = 512;
			res = RES_OK;
			break;

		case CTRL_SYNC :	/* Flush dirty buffer if present */
			if (wait_ready() == 0xFF)
				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(buff, 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(buff, 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 = 0; n < 4; n++)
					*((BYTE*)buff+n) = rcvr_spi();
				res = RES_OK;
			}
			break;

		default:
			res = RES_PARERR;
	}

	DESELECT();			/* CS = H */
	rcvr_spi();			/* Idle (Release DO) */

	return res;
}



/*-----------------------------------------------------------------------*/
/* Device Timer Interrupt Procedure  (Platform dependent)                */
/*-----------------------------------------------------------------------*/
/* This function must be called in period of 1ms                         */


void disk_timerproc (void)
{
	static BYTE pv;
	BYTE s, p;
	UINT n;


	n = Timer1;						/* 1000Hz decrement timer */
	if (n) Timer1 = --n;
	n = Timer2;
	if (n) Timer2 = --n;

	p = pv;
	pv = SOCKPORT & (SOCKWP | SOCKINS);	/* Sample socket switch */

	if (p == pv) {					/* Have contacts stabled? */
		s = Stat;

		if (p & SOCKWP)				/* WP is H (write protected) */
			s |= STA_PROTECT;
		else						/* WP is L (write enabled) */
			s &= ~STA_PROTECT;

		if (p & SOCKINS)			/* INS = H (Socket empty) */
			s |= (STA_NODISK | STA_NOINIT);
		else						/* INS = L (Card inserted) */
			s &= ~STA_NODISK;

		Stat = s;
	}
}