/*------------------------------------------------------------------------/
/  Foolproof MMCv3/SDv1/SDv2 (in SPI mode) control module
/-------------------------------------------------------------------------/
/
/  Copyright (C) 2013, ChaN, all right reserved.
/
/ * This software is a free software and there is NO WARRANTY.
/ * No restriction on use. You can use, modify and redistribute it for
/   personal, non-profit or commercial products UNDER YOUR RESPONSIBILITY.
/ * Redistributions of source code must retain the above copyright notice.
/
/-------------------------------------------------------------------------/
  Features and Limitations:

  * Easy to Port Bit-banging SPI
    It uses only four GPIO pins. No complex peripheral needs to be used.

  * Platform Independent
    You need to modify only a few macros to control the GPIO port.

  * Low Speed
    The data transfer rate will be several times slower than hardware SPI.

  * No Media Change Detection
    Application program needs to perform a f_mount() after media change.

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


#include "ff.h"        /* Obtains integer types for FatFs */
#include "diskio.h"    /* Common include file for FatFs and disk I/O layer */


/*-------------------------------------------------------------------------*/
/* Platform dependent macros and functions needed to be modified           */
/*-------------------------------------------------------------------------*/

//#include <avr/io.h>            /* Include device specific declareation file here */
#include "zpu-types.h"
#include "zpu_soc.h"
#define PORTB


#define DO_INIT()                      /* Initialize port for MMC DO as input */
#define DO            1 //(PINB &  0x01)   /* Test for MMC DO ('H':true, 'L':false) */

#define DI_INIT()     SPI_DATA(SPI0) |= 0x02 //DDRB  |= 0x02    /* Initialize port for MMC DI as output */
#define DI_H()        SPI_DATA(SPI0) |= 0x02 //PORTB |= 0x02    /* Set MMC DI "high" */
#define DI_L()        SPI_DATA(SPI0) &= 0xFD //PORTB &= 0xFD    /* Set MMC DI "low" */

#define CK_INIT()     SPI_DATA(SPI0) |= 0x04 //DDRB  |= 0x04    /* Initialize port for MMC SCLK as output */
#define CK_H()        SPI_DATA(SPI0) |= 0x04 //PORTB |= 0x04    /* Set MMC SCLK "high" */
#define CK_L()        SPI_DATA(SPI0) &= 0xFB //PORTB &= 0xFB    /* Set MMC SCLK "low" */

#define CS_INIT()     SPI_DATA(SPI0) |= 0x08 //DDRB  |= 0x08    /* Initialize port for MMC CS as output */
#define CS_H()        SPI_DATA(SPI0) |= 0x08 //PORTB |= 0x08    /* Set MMC CS "high" */
#define CS_L()        SPI_DATA(SPI0) &= 0xF8 //PORTB &= 0xF7    /* Set MMC CS "low" */


static
void dly_us (UINT n)    /* Delay n microseconds (avr-gcc -Os) */
{
    uint32_t start = TIMER_MICROSECONDS(TIMER0);
    while(n > 0)
    {
        if(start != TIMER_MICROSECONDS(TIMER0))
        {
            --n;
            start = TIMER_MICROSECONDS(TIMER0);
        }
    }
}


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

   Module Private Functions

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

/* MMC/SD command (SPI mode) */
#define CMD0     (0)         /* GO_IDLE_STATE */
#define CMD1     (1)         /* SEND_OP_COND */
#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 CMD13    (13)        /* SEND_STATUS */
#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 */
#define ACMD23   (0x80+23)   /* SET_WR_BLK_ERASE_COUNT (SDC) */
#define CMD24    (24)        /* WRITE_BLOCK */
#define CMD25    (25)        /* WRITE_MULTIPLE_BLOCK */
#define CMD32    (32)        /* ERASE_ER_BLK_START */
#define CMD33    (33)        /* ERASE_ER_BLK_END */
#define CMD38    (38)        /* ERASE */
#define CMD55    (55)        /* APP_CMD */
#define CMD58    (58)        /* READ_OCR */


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

static
BYTE CardType;            /* b0:MMC, b1:SDv1, b2:SDv2, b3:Block addressing */



/*-----------------------------------------------------------------------*/
/* Transmit bytes to the card (bitbanging)                               */
/*-----------------------------------------------------------------------*/

static
void xmit_mmc (
    const BYTE* buff,    /* Data to be sent */
    UINT bc                /* Number of bytes to send */
)
{
    BYTE d;


    do {
        d = *buff++;    /* Get a byte to be sent */
        if (d & 0x80) DI_H(); else DI_L();    /* bit7 */
        CK_H(); CK_L();
        if (d & 0x40) DI_H(); else DI_L();    /* bit6 */
        CK_H(); CK_L();
        if (d & 0x20) DI_H(); else DI_L();    /* bit5 */
        CK_H(); CK_L();
        if (d & 0x10) DI_H(); else DI_L();    /* bit4 */
        CK_H(); CK_L();
        if (d & 0x08) DI_H(); else DI_L();    /* bit3 */
        CK_H(); CK_L();
        if (d & 0x04) DI_H(); else DI_L();    /* bit2 */
        CK_H(); CK_L();
        if (d & 0x02) DI_H(); else DI_L();    /* bit1 */
        CK_H(); CK_L();
        if (d & 0x01) DI_H(); else DI_L();    /* bit0 */
        CK_H(); CK_L();
    } while (--bc);
}



/*-----------------------------------------------------------------------*/
/* Receive bytes from the card (bitbanging)                              */
/*-----------------------------------------------------------------------*/

static
void rcvr_mmc (
    BYTE *buff,    /* Pointer to read buffer */
    UINT bc        /* Number of bytes to receive */
)
{
    BYTE r;


    DI_H();    /* Send 0xFF */

    do {
        r = 0;     if (DO) r++;    /* bit7 */
        CK_H(); CK_L();
        r <<= 1; if (DO) r++;    /* bit6 */
        CK_H(); CK_L();
        r <<= 1; if (DO) r++;    /* bit5 */
        CK_H(); CK_L();
        r <<= 1; if (DO) r++;    /* bit4 */
        CK_H(); CK_L();
        r <<= 1; if (DO) r++;    /* bit3 */
        CK_H(); CK_L();
        r <<= 1; if (DO) r++;    /* bit2 */
        CK_H(); CK_L();
        r <<= 1; if (DO) r++;    /* bit1 */
        CK_H(); CK_L();
        r <<= 1; if (DO) r++;    /* bit0 */
        CK_H(); CK_L();
        *buff++ = r;            /* Store a received byte */
    } while (--bc);
}



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

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


    for (tmr = 5000; tmr; tmr--) {    /* Wait for ready in timeout of 500ms */
        rcvr_mmc(&d, 1);
        if (d == 0xFF) break;
        dly_us(100);
    }

    return tmr ? 1 : 0;
}



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

static
void deselect (void)
{
    BYTE d;

    CS_H();                /* Set CS# high */
    rcvr_mmc(&d, 1);    /* Dummy clock (force DO hi-z for multiple slave SPI) */
}



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

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

    CS_L();                /* Set CS# low */
    rcvr_mmc(&d, 1);    /* Dummy clock (force DO enabled) */
    if (wait_ready()) return 1;    /* Wait for card ready */

    deselect();
    return 0;            /* Failed */
}



/*-----------------------------------------------------------------------*/
/* Receive a data packet from the card                                   */
/*-----------------------------------------------------------------------*/

static
int rcvr_datablock (    /* 1:OK, 0:Failed */
    BYTE *buff,            /* Data buffer to store received data */
    UINT btr            /* Byte count */
)
{
    BYTE d[2];
    UINT tmr;


    for (tmr = 1000; tmr; tmr--) {    /* Wait for data packet in timeout of 100ms */
        rcvr_mmc(d, 1);
        if (d[0] != 0xFF) break;
        dly_us(100);
    }
    if (d[0] != 0xFE) return 0;        /* If not valid data token, return with error */

    rcvr_mmc(buff, btr);            /* Receive the data block into buffer */
    rcvr_mmc(d, 2);                    /* Discard CRC */

    return 1;                        /* Return with success */
}



/*-----------------------------------------------------------------------*/
/* Send a data packet to the card                                        */
/*-----------------------------------------------------------------------*/

static
int xmit_datablock (    /* 1:OK, 0:Failed */
    const BYTE *buff,    /* 512 byte data block to be transmitted */
    BYTE token            /* Data/Stop token */
)
{
    BYTE d[2];


    if (!wait_ready()) return 0;

    d[0] = token;
    xmit_mmc(d, 1);                /* Xmit a token */
    if (token != 0xFD) {        /* Is it data token? */
        xmit_mmc(buff, 512);    /* Xmit the 512 byte data block to MMC */
        rcvr_mmc(d, 2);            /* Xmit dummy CRC (0xFF,0xFF) */
        rcvr_mmc(d, 1);            /* Receive data response */
        if ((d[0] & 0x1F) != 0x05)    /* If not accepted, return with error */
            return 0;
    }

    return 1;
}



/*-----------------------------------------------------------------------*/
/* Send a command packet to the card                                     */
/*-----------------------------------------------------------------------*/

static
BYTE send_cmd (        /* Returns command response (bit7==1:Send failed)*/
    BYTE cmd,        /* Command byte */
    DWORD arg        /* Argument */
)
{
    BYTE n, d, buf[6];


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

    /* Select the card and wait for ready except to stop multiple block read */
    if (cmd != CMD12) {
        deselect();
        if (!select()) return 0xFF;
    }

    /* Send a command packet */
    buf[0] = 0x40 | cmd;            /* Start + Command index */
    buf[1] = (BYTE)(arg >> 24);        /* Argument[31..24] */
    buf[2] = (BYTE)(arg >> 16);        /* Argument[23..16] */
    buf[3] = (BYTE)(arg >> 8);        /* Argument[15..8] */
    buf[4] = (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)) */
    buf[5] = n;
    xmit_mmc(buf, 6);

    /* Receive command response */
    if (cmd == CMD12) rcvr_mmc(&d, 1);    /* Skip a stuff byte when stop reading */
    n = 10;                                /* Wait for a valid response in timeout of 10 attempts */
    do
        rcvr_mmc(&d, 1);
    while ((d & 0x80) && --n);

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



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

   Public Functions

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


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

DSTATUS disk_status (
    BYTE drv            /* Drive number (always 0) */
)
{
    if (drv) return STA_NOINIT;

    return Stat;
}



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

DSTATUS disk_initialize (
    BYTE drv        /* Physical drive nmuber (0) */
)
{
    BYTE n, ty, cmd, buf[4];
    UINT tmr;
    DSTATUS s;


    if (drv) return RES_NOTRDY;

    dly_us(10000);            /* 10ms */
    CS_INIT(); CS_H();        /* Initialize port pin tied to CS */
    CK_INIT(); CK_L();        /* Initialize port pin tied to SCLK */
    DI_INIT();                /* Initialize port pin tied to DI */
    DO_INIT();                /* Initialize port pin tied to DO */

    for (n = 10; n; n--) rcvr_mmc(buf, 1);    /* Apply 80 dummy clocks and the card gets ready to receive command */

    ty = 0;
    if (send_cmd(CMD0, 0) == 1) {            /* Enter Idle state */
        if (send_cmd(CMD8, 0x1AA) == 1) {    /* SDv2? */
            rcvr_mmc(buf, 4);                            /* Get trailing return value of R7 resp */
            if (buf[2] == 0x01 && buf[3] == 0xAA) {        /* The card can work at vdd range of 2.7-3.6V */
                for (tmr = 1000; tmr; tmr--) {            /* Wait for leaving idle state (ACMD41 with HCS bit) */
                    if (send_cmd(ACMD41, 1UL << 30) == 0) break;
                    dly_us(1000);
                }
                if (tmr && send_cmd(CMD58, 0) == 0) {    /* Check CCS bit in the OCR */
                    rcvr_mmc(buf, 4);
                    ty = (buf[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 */
            }
            for (tmr = 1000; tmr; tmr--) {            /* Wait for leaving idle state */
                if (send_cmd(cmd, 0) == 0) break;
                dly_us(1000);
            }
            if (!tmr || send_cmd(CMD16, 512) != 0)    /* Set R/W block length to 512 */
                ty = 0;
        }
    }
    CardType = ty;
    s = ty ? 0 : STA_NOINIT;
    Stat = s;

    deselect();

    return s;
}



/*-----------------------------------------------------------------------*/
/* 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..128) */
)
{
    BYTE cmd;


    if (disk_status(drv) & STA_NOINIT) return RES_NOTRDY;
    if (!(CardType & CT_BLOCK)) sector *= 512;    /* Convert LBA to byte address if needed */

    cmd = count > 1 ? CMD18 : CMD17;            /*  READ_MULTIPLE_BLOCK : READ_SINGLE_BLOCK */
    if (send_cmd(cmd, sector) == 0) {
        do {
            if (!rcvr_datablock(buff, 512)) break;
            buff += 512;
        } while (--count);
        if (cmd == CMD18) 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..128) */
)
{
    if (disk_status(drv) & STA_NOINIT) return RES_NOTRDY;
    if (!(CardType & CT_BLOCK)) sector *= 512;    /* Convert LBA 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];
    DWORD cs;


    if (disk_status(drv) & STA_NOINIT) return RES_NOTRDY;    /* Check if card is in the socket */

    res = RES_ERROR;
    switch (ctrl) {
        case CTRL_SYNC :        /* Make sure that no pending write process */
            if (select()) 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 */
                    cs = csd[9] + ((WORD)csd[8] << 8) + ((DWORD)(csd[7] & 63) << 16) + 1;
                    *(DWORD*)buff = cs << 10;
                } else {                    /* SDC ver 1.XX or MMC */
                    n = (csd[5] & 15) + ((csd[10] & 128) >> 7) + ((csd[9] & 3) << 1) + 2;
                    cs = (csd[8] >> 6) + ((WORD)csd[7] << 2) + ((WORD)(csd[6] & 3) << 10) + 1;
                    *(DWORD*)buff = cs << (n - 9);
                }
                res = RES_OK;
            }
            break;

        case GET_BLOCK_SIZE :    /* Get erase block size in unit of sector (DWORD) */
            *(DWORD*)buff = 128;
            res = RES_OK;
            break;

        default:
            res = RES_PARERR;
    }

    deselect();

    return res;
}


