open-story-teller/software/system/ff_diskio_sdcard.c

#define PIN_SPI0_CS 17
#define PIN_SPI0_SCK 18
#define PIN_SPI0_MOSI 19
#define PIN_SPI0_MISO 16

// const uint8_t SD_CARD_CS = 17;
// #define SDCARD_SCK 18
// #define SDCARD_MOSI 19
// #define SDCARD_MISO 16

#include "pico.h"
#include "pico/stdlib.h"
#include "hardware/clocks.h"
#include "hardware/spi.h"
#include "hardware/gpio.h"

#include "ff.h"
#include "diskio.h"

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

   Module Private Functions

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

/* MMC/SD 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 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 */

/* MMC card type flags (MMC_GET_TYPE) */
#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 */

#define CLK_SLOW (100 * KHZ)
#define CLK_FAST (40 * MHZ)

static volatile DSTATUS Stat = STA_NOINIT; /* Physical drive status */

static BYTE CardType; /* Card type flags */

static inline uint32_t _millis(void)
{
	return to_ms_since_boot(get_absolute_time());
}

/*-----------------------------------------------------------------------*/
/* SPI controls (Platform dependent)                                     */
/*-----------------------------------------------------------------------*/

static inline void cs_select(uint cs_pin)
{
	asm volatile("nop \n nop \n nop"); // FIXME
	gpio_put(cs_pin, 0);
	asm volatile("nop \n nop \n nop"); // FIXME
}

static inline void cs_deselect(uint cs_pin)
{
	asm volatile("nop \n nop \n nop"); // FIXME
	gpio_put(cs_pin, 1);
	asm volatile("nop \n nop \n nop"); // FIXME
}

static void FCLK_SLOW(void)
{
	spi_set_baudrate(spi0, CLK_SLOW);
}

static void FCLK_FAST(void)
{
	spi_set_baudrate(spi0, CLK_FAST);
}

static void CS_HIGH(void)
{
	cs_deselect(PIN_SPI0_CS);
}

static void CS_LOW(void)
{
	cs_select(PIN_SPI0_CS);
}

/* Initialize MMC interface */
void init_spi(void)
{
	/* GPIO pin configuration */
	/* pull up of MISO is MUST (10Kohm external pull up is recommended) */
	/* Set drive strength and slew rate if needed to meet wire condition */
	gpio_init(PIN_SPI0_SCK);
	gpio_disable_pulls(PIN_SPI0_SCK);
	// gpio_pull_up(PIN_SPI0_SCK);
	// gpio_set_drive_strength(PIN_SPI0_SCK, PADS_BANK0_GPIO0_DRIVE_VALUE_4MA); // 2mA, 4mA (default), 8mA, 12mA
	// gpio_set_slew_rate(PIN_SPI0_SCK, 0); // 0: SLOW (default), 1: FAST
	gpio_set_function(PIN_SPI0_SCK, GPIO_FUNC_SPI);

	gpio_init(PIN_SPI0_MISO);
	gpio_disable_pulls(PIN_SPI0_MISO);
	// gpio_pull_up(PIN_SPI0_MISO);
	// gpio_set_schmitt(PIN_SPI0_MISO, 1); // 0: Off, 1: On (default)
	gpio_set_function(PIN_SPI0_MISO, GPIO_FUNC_SPI);

	gpio_init(PIN_SPI0_MOSI);
	gpio_disable_pulls(PIN_SPI0_MOSI);
	// gpio_pull_up(PIN_SPI0_MOSI);
	// gpio_set_drive_strength(PIN_SPI0_MOSI, PADS_BANK0_GPIO0_DRIVE_VALUE_4MA); // 2mA, 4mA (default), 8mA, 12mA
	// gpio_set_slew_rate(PIN_SPI0_MOSI, 0); // 0: SLOW (default), 1: FAST
	gpio_set_function(PIN_SPI0_MOSI, GPIO_FUNC_SPI);

	gpio_init(PIN_SPI0_CS);
	gpio_disable_pulls(PIN_SPI0_CS);
	// gpio_pull_up(PIN_SPI0_CS);
	// gpio_set_drive_strength(PIN_SPI0_CS, PADS_BANK0_GPIO0_DRIVE_VALUE_4MA); // 2mA, 4mA (default), 8mA, 12mA
	// gpio_set_slew_rate(PIN_SPI0_CS, 0); // 0: SLOW (default), 1: FAST
	gpio_set_dir(PIN_SPI0_CS, GPIO_OUT);

	/* chip _select invalid*/
	CS_HIGH();

	spi_init(spi0, CLK_SLOW);

	/* SPI0 parameter config */
	spi_set_format(spi0,
				   8,			 /* data_bits */
				   SPI_CPOL_0,	 /* cpol */
				   SPI_CPHA_0,	 /* cpha */
				   SPI_MSB_FIRST /* order */
	);
}

/* Exchange a byte */
static BYTE xchg_spi(
	BYTE dat /* Data to send */
)
{
	uint8_t *buff = (uint8_t *)&dat;
	spi_write_read_blocking(spi0, buff, buff, 1);
	return (BYTE)*buff;
}

/* Receive multiple byte */
static void rcvr_spi_multi(
	BYTE *buff, /* Pointer to data buffer */
	UINT btr	/* Number of bytes to receive (even number) */
)
{
	uint8_t *b = (uint8_t *)buff;
	spi_read_blocking(spi0, 0xff, b, btr);
}

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

static int wait_ready(		  /* 1:Ready, 0:Timeout */
					  UINT wt /* Timeout [ms] */
)
{
	BYTE d;

	uint32_t t = _millis();
	do
	{
		d = xchg_spi(0xFF);
		/* This loop takes a time. Insert rot_rdq() here for multitask envilonment. */
	} while (d != 0xFF && _millis() < t + wt); /* Wait for card goes ready or timeout */

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

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

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

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

static int _select(void) /* 1:OK, 0:Timeout */
{
	CS_LOW();		/* Set CS# low */
	xchg_spi(0xFF); /* Dummy clock (force DO enabled) */
	if (wait_ready(500))
		return 1; /* Wait for card ready */

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

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

static int rcvr_datablock(			  /* 1:OK, 0:Error */
						  BYTE *buff, /* Data buffer */
						  UINT btr	  /* Data block length (byte) */
)
{
	BYTE token;

	const uint32_t timeout = 200;
	uint32_t t = _millis();
	do
	{ /* Wait for DataStart token in timeout of 200ms */
		token = xchg_spi(0xFF);
		/* This loop will take a time. Insert rot_rdq() here for multitask envilonment. */
	} while (token == 0xFF && _millis() < t + timeout);
	if (token != 0xFE)
		return 0; /* Function fails if invalid DataStart token or timeout */

	rcvr_spi_multi(buff, btr); /* Store trailing data to the buffer */
	xchg_spi(0xFF);
	xchg_spi(0xFF); /* Discard CRC */

	return 1; /* Function succeeded */
}

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

static BYTE send_cmd(		   /* Return value: R1 resp (bit7==1:Failed to send) */
					 BYTE cmd, /* Command index */
					 DWORD arg /* Argument */
)
{
	BYTE n, res;

	if (cmd & 0x80)
	{ /* Send a CMD55 prior to ACMD<n> */
		cmd &= 0x7F;
		res = send_cmd(CMD55, 0);
		if (res > 1)
			return res;
	}

	/* Select the card and wait for ready except to stop multiple block read */
	if (cmd != CMD12)
	{
		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) */
	if (cmd == CMD8)
		n = 0x87; /* Valid CRC for CMD8(0x1AA) */
	xchg_spi(n);

	/* Receive command resp */
	if (cmd == CMD12)
		xchg_spi(0xFF); /* Diacard following one byte when CMD12 */
	n = 10;				/* Wait for response (10 bytes max) */
	do
	{
		res = xchg_spi(0xFF);
	} while ((res & 0x80) && --n);

	return res; /* Return received response */
}

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

   Public Functions

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

/*-----------------------------------------------------------------------*/
/* Initialize disk drive                                                 */
/*-----------------------------------------------------------------------*/

DSTATUS disk_initialize(
	BYTE drv /* Physical drive number (0) */
)
{
	BYTE n, cmd, ty, ocr[4];
	const uint32_t timeout = 1000; /* Initialization timeout = 1 sec */
	uint32_t t;

	if (drv)
		return STA_NOINIT; /* Supports only drive 0 */
	init_spi();			   /* Initialize SPI */
	sleep_ms(10);

	if (Stat & STA_NODISK)
		return Stat; /* Is card existing in the soket? */

	FCLK_SLOW();
	for (n = 10; n; n--)
		xchg_spi(0xFF); /* Send 80 dummy clocks */

	ty = 0;
	if (send_cmd(CMD0, 0) == 1)
	{ /* Put the card SPI/Idle state */
		t = _millis();
		if (send_cmd(CMD8, 0x1AA) == 1)
		{ /* SDv2? */
			for (n = 0; n < 4; n++)
				ocr[n] = xchg_spi(0xFF); /* Get 32 bit return value of R7 resp */
			if (ocr[2] == 0x01 && ocr[3] == 0xAA)
			{ /* Is the card supports vcc of 2.7-3.6V? */
				while (_millis() < t + timeout && send_cmd(ACMD41, 1UL << 30))
					; /* Wait for end of initialization with ACMD41(HCS) */
				if (_millis() < t + timeout && 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; /* Card id SDv2 */
				}
			}
		}
		else
		{ /* Not SDv2 card */
			if (send_cmd(ACMD41, 0) <= 1)
			{ /* SDv1 or MMC? */
				ty = CT_SD1;
				cmd = ACMD41; /* SDv1 (ACMD41(0)) */
			}
			else
			{
				ty = CT_MMC;
				cmd = CMD1; /* MMCv3 (CMD1(0)) */
			}
			while (_millis() < t + timeout && send_cmd(cmd, 0))
				;													   /* Wait for end of initialization */
			if (_millis() >= t + timeout || send_cmd(CMD16, 512) != 0) /* Set block length: 512 */
				ty = 0;
		}
	}
	CardType = ty; /* Card type */
	deselect();

	if (ty)
	{						 /* OK */
		FCLK_FAST();		 /* Set fast clock */
		Stat &= ~STA_NOINIT; /* Clear STA_NOINIT flag */
	}
	else
	{ /* Failed */
		Stat = STA_NOINIT;
	}

	return Stat;
}

/*-----------------------------------------------------------------------*/
/* Get disk status                                                       */
/*-----------------------------------------------------------------------*/

DSTATUS disk_status(
	BYTE drv /* Physical drive number (0) */
)
{
	if (drv)
		return STA_NOINIT; /* Supports only drive 0 */

	return Stat; /* Return disk status */
}

/*-----------------------------------------------------------------------*/
/* Read sector(s)                                                        */
/*-----------------------------------------------------------------------*/

DRESULT disk_read(
	BYTE drv,	  /* Physical drive number (0) */
	BYTE *buff,	  /* Pointer to the data buffer to store read data */
	LBA_t sector, /* Start sector number (LBA) */
	UINT count	  /* Number of sectors to read (1..128) */
)
{
	if (drv || !count)
		return RES_PARERR; /* Check parameter */
	if (Stat & STA_NOINIT)
		return RES_NOTRDY; /* Check if drive is ready */

	if (!(CardType & CT_BLOCK))
		sector *= 512; /* LBA ot BA conversion (byte addressing cards) */

	if (count == 1)
	{									   /* Single sector read */
		if ((send_cmd(CMD17, sector) == 0) /* READ_SINGLE_BLOCK */
			&& rcvr_datablock(buff, 512))
		{
			count = 0;
		}
	}
	else
	{ /* Multiple sector 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; /* Return result */
}

#if !FF_FS_READONLY && !FF_FS_NORTC
/* get the current time */
DWORD get_fattime(void)
{
	return 0;
}
#endif

#if FF_FS_READONLY == 0
/* Transmit multiple byte */
static void xmit_spi_multi(
	const BYTE *buff, /* Pointer to data buffer */
	UINT btx		  /* Number of bytes to transmit (even number) */
)
{
	const uint8_t *b = (const uint8_t *)buff;
	spi_write_blocking(spi0, b, btx);
}

/*-----------------------------------------------------------------------*/
/* Transmit a data packet to the MMC                                     */
/*-----------------------------------------------------------------------*/

static int xmit_datablock(					/* 1:OK, 0:Error */
						  const BYTE *buff, /* 512 byte data block to be transmitted */
						  BYTE token		/* Data/Stop token */
)
{
	BYTE resp;
	if (!wait_ready(500))
		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;
}

/*-----------------------------------------------------------------------*/
/* Write sector(s)                                                       */
/*-----------------------------------------------------------------------*/

DRESULT disk_write(
	BYTE drv,		  /* Physical drive number (0) */
	const BYTE *buff, /* Ponter to the data to write */
	LBA_t sector,	  /* Start sector number (LBA) */
	UINT count		  /* Number of sectors to write (1..128) */
)
{
	if (drv || !count)
		return RES_PARERR; /* Check parameter */
	if (Stat & STA_NOINIT)
		return RES_NOTRDY; /* Check drive status */
	if (Stat & STA_PROTECT)
		return RES_WRPRT; /* Check write protect */

	if (!(CardType & CT_BLOCK))
		sector *= 512; /* LBA ==> BA conversion (byte addressing cards) */

	if (!_select())
		return RES_NOTRDY;

	if (count == 1)
	{									   /* Single sector write */
		if ((send_cmd(CMD24, sector) == 0) /* WRITE_BLOCK */
			&& xmit_datablock(buff, 0xFE))
		{
			count = 0;
		}
	}
	else
	{ /* Multiple sector write */
		if (CardType & CT_SDC)
			send_cmd(ACMD23, count); /* Predefine number of sectors */
		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))
				count = 1; /* STOP_TRAN token */
		}
	}
	deselect();

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

/*-----------------------------------------------------------------------*/
/* Miscellaneous drive controls other than data read/write               */
/*-----------------------------------------------------------------------*/

DRESULT disk_ioctl(
	BYTE drv,  /* Physical drive number (0) */
	BYTE cmd,  /* Control command code */
	void *buff /* Pointer to the conrtol data */
)
{
	DRESULT res;
	BYTE n, csd[16];
	DWORD *dp, st, ed, csize;

	if (drv)
		return RES_PARERR; /* Check parameter */
	if (Stat & STA_NOINIT)
		return RES_NOTRDY; /* Check if drive is ready */

	res = RES_ERROR;

	switch (cmd)
	{
	case CTRL_SYNC: /* Wait for end of internal write process of the drive */
		if (_select())
			res = RES_OK;
		break;

	case GET_SECTOR_COUNT: /* Get drive capacity in unit of sector (DWORD) */
		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) + ((DWORD)(csd[7] & 63) << 16) + 1;
				*(DWORD *)buff = csize << 10;
			}
			else
			{ /* SDC ver 1.XX or MMC ver 3 */
				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 = csize << (n - 9);
			}
			res = RES_OK;
		}
		break;

	case GET_BLOCK_SIZE: /* Get erase block size in unit of sector (DWORD) */
		if (CardType & CT_SD2)
		{ /* SDC ver 2.00 */
			if (send_cmd(ACMD13, 0) == 0)
			{ /* Read SD status */
				xchg_spi(0xFF);
				if (rcvr_datablock(csd, 16))
				{ /* Read partial block */
					for (n = 64 - 16; n; n--)
						xchg_spi(0xFF); /* Purge trailing data */
					*(DWORD *)buff = 16UL << (csd[10] >> 4);
					res = RES_OK;
				}
			}
		}
		else
		{ /* SDC ver 1.XX or MMC */
			if ((send_cmd(CMD9, 0) == 0) && rcvr_datablock(csd, 16))
			{ /* Read CSD */
				if (CardType & CT_SD1)
				{ /* SDC ver 1.XX */
					*(DWORD *)buff = (((csd[10] & 63) << 1) + ((WORD)(csd[11] & 128) >> 7) + 1) << ((csd[13] >> 6) - 1);
				}
				else
				{ /* MMC */
					*(DWORD *)buff = ((WORD)((csd[10] & 124) >> 2) + 1) * (((csd[11] & 3) << 3) + ((csd[11] & 224) >> 5) + 1);
				}
				res = RES_OK;
			}
		}
		break;

	case CTRL_TRIM: /* Erase a block of sectors (used when _USE_ERASE == 1) */
		if (!(CardType & CT_SDC))
			break; /* Check if the card is SDC */
		if (disk_ioctl(drv, MMC_GET_CSD, csd))
			break; /* Get CSD */
		if (!(csd[0] >> 6) && !(csd[10] & 0x40))
			break; /* Check if sector erase can be applied to the card */
		dp = buff;
		st = dp[0];
		ed = dp[1]; /* Load sector block */
		if (!(CardType & CT_BLOCK))
		{
			st *= 512;
			ed *= 512;
		}
		if (send_cmd(CMD32, st) == 0 && send_cmd(CMD33, ed) == 0 && send_cmd(CMD38, 0) == 0 && wait_ready(30000))
		{				  /* Erase sector block */
			res = RES_OK; /* FatFs does not check result of this command */
		}
		break;

	default:
		res = RES_PARERR;
	}

	deselect();

	return res;
}