mmc.c

超轻量级的嵌入式文件系统

/*-----------------------------------------------------------------------*/
/* MMC/SDSC/SDHC (in SPI mode) control module  (C)ChaN, 2007             */
/*-----------------------------------------------------------------------*/
/* Only rcvr_spi(), xmit_spi(), disk_timerproc() and some macros         */
/* are platform dependent.                                               */
/*-----------------------------------------------------------------------*/


#include "io86fm29.h"
#include "integer.h"
#include "diskio.h"


/* Definitions for MMC/SDC command */
#define CMD0	(0x40+0)	/* GO_IDLE_STATE */
#define CMD1	(0x40+1)	/* SEND_OP_COND (MMC) */
#define	ACMD41	(0xC0+41)	/* SEND_OP_COND (SDC) */
#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 ACMD13	(0xC0+13)	/* SD_STATUS (SDC) */
#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 (MMC) */
#define	ACMD23	(0xC0+23)	/* SET_WR_BLK_ERASE_COUNT (SDC) */
#define CMD24	(0x40+24)	/* WRITE_BLOCK */
#define CMD25	(0x40+25)	/* WRITE_MULTIPLE_BLOCK */
#define CMD55	(0x40+55)	/* APP_CMD */
#define CMD58	(0x40+58)	/* READ_OCR */


/* Control signals (Platform dependent) */
#define MMPORT		P3DR
#define MMPIN		P3PRD
#define MMCTRL		P3OUTCR
#define MMCLK		0x01	/* MMC SCLK */
#define MMDO		0x02	/* MMC DO */
#define MMDI		0x04	/* MMC DI */
#define	MMCS		0x08	/* MMC CS */
#define SELECT()	MMPORT &= ~MMCS	/* MMC CS = L */
#define	DESELECT()	MMPORT |= MMCS	/* MMC CS = H */

#define SOCKPORT	P5DR		/* Socket control port output */
#define SOCKPIN		P5PRD		/* Socket control port input */
#define SOCKINS		0x01		/* Card detect switch (P50) */
#define SOCKWP		0x02		/* Write protect switch (P51) */
#define CARDPWR		0x04		/* Card power (P52) */



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

   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:SDv1, b2:SDv2, b3:Block addressing */



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

static
void xmit_spi (BYTE dat)
{
	BYTE n = 8;


	do {
		if (dat & 0x80)
			MMPORT |= MMDI;
		else
			MMPORT &= ~MMDI;
		dat <<= 1;
		MMPORT |= MMCLK;
		MMPORT &= ~MMCLK;
	} while (--n);
}



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

static
BYTE rcvr_spi()
{
	BYTE r = 0, n = 8;


	MMPORT |= MMDI;
	do {
		r <<= 1;
		if (MMPIN & MMDO) r++;
		MMPORT |= MMCLK;
		MMPORT &= ~MMCLK;
	} while (--n);
	return r;
}



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

static
BYTE wait_ready ()
{
	BYTE res;


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



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

static
void release_spi (void)
{
	DESELECT();
	rcvr_spi();
}



/*-----------------------------------------------------------------------*/
/* 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)
{
	SOCKPORT = 0x03;			/* Power ON */
	for (Timer1 = 2; Timer1; );	/* Wait for 20ms */
	MMPORT = 0x0E;				/* Enable Driver */
	MMCTRL = 0x0D;
	for (Timer1 = 1; Timer1; );	/* Wait for 10ms */

}

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

	MMCTRL = 0x00;			/* Disable driver */
	SOCKPORT = 0x07;		/* Power OFF */
	Stat |= STA_NOINIT;		/* Set STA_NOINIT */
}



/*-----------------------------------------------------------------------*/
/* 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 */
		*buff++ = rcvr_spi();
		*buff++ = rcvr_spi();
	} 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 (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();
	SELECT();
	if (wait_ready() != 0xFF) return 0xFF;

	/* Send command packet */
	xmit_spi(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;							/* Duumy 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