/*
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/io.h>

#define FLOPPY		0x3F0	/* default floppy */

#define	FLOPPY_DOR	(FLOPPY + 0x2)
#define	FLOPPY_DIR	(FLOPPY + 0x7)

#define	FDOR_MOTEA	0x10
#define	FDOR_MOTEB	0x20
#define	FDOR_DSEL0	0x01
#define	FDOR_DSEL1	0x02

#define	FDIR_DCHNG	0x80

#define SCL		FDOR_MOTEA
#define	SDA		FDOR_MOTEB
#define SDA_IN		FDIR_DCHNG

#define	LO_INV		(SDA|SCL)
#define	LI_INV		(SDA_IN)


static unsigned char dor = (SCL | SDA);

static unsigned int delay = 500;
static unsigned int level = 1;


#define udelay(a)	do { } while (0)

#define dprintf(l, f, x...) do {		\
	if (level >= l) printf(f , ##x);	\
	} while (0)


void out_dor(unsigned char data)
{
    outb(data ^ LO_INV, FLOPPY_DOR);
    dprintf(5, "  >  SCL=%d SDA=%d\n",
	(data & SCL) ? 1 : 0, (data & SDA) ? 1 : 0); 
}

unsigned char in_dir(void)
{
    unsigned char in = inb(FLOPPY_DIR) ^ LI_INV;
    dprintf(5, "  <        SDA=%d\n",
	(in & SDA_IN) ? 1 : 0); 
    return in;
}


unsigned char pulse_scl(void)
{
    /* take SCL high */
    dor |= SCL;
    out_dor(dor);
    udelay(delay);

    /* read back data */
    unsigned char bit = in_dir() & SDA_IN;
    udelay(delay);

    /* take SCL low again */
    dor &= ~SCL;
    out_dor(dor);

    /* return value */
    return bit ? 1 : 0;
}

void out_start(void)
{
    /* clear SDA with SCL high */
    dor &= ~SDA;
    out_dor(dor);
    udelay(delay);

    /* take SCL low */
    dor &= ~SCL;
    out_dor(dor);
    udelay(delay);
}

void out_stop(void)
{
    /* take SDA low */
    dor &= ~SDA;
    out_dor(dor);
    udelay(delay);

    /* pull SCL high */
    dor |= SCL;
    out_dor(dor);
    udelay(delay);

    /* take SDA high */
    dor |= SDA;
    out_dor(dor);
    udelay(delay);
}

unsigned char out_bit(unsigned char bit)
{
    /* output data bit */
    dor = (dor & ~SDA) | (bit ? SDA : 0);
    out_dor(dor);
    udelay(delay);

    /* pulse and readback */
    unsigned char ret = pulse_scl();
    udelay(delay);

    return ret;
}

unsigned char in_bit(void)
{
    /* take SDA high for readback */
    dor |= SDA;
    out_dor(dor);
    udelay(delay);

    /* pulse and readback */
    unsigned char bit = pulse_scl();
    udelay(delay);

    return bit;
}

    

void out_byte(unsigned char byte)
{
    int i;
    unsigned char val = 0;

    for (i=7; i>=0; i--) {
	int bit = (byte & (1 << i)) ? 1 : 0;
	int ret = out_bit(bit);
	val = val << 1 | ret;
	dprintf(3, "[O%d] %d %d\n", i, bit, ret); 
    }
    int ack = in_bit();
    dprintf(2, "[A*] %d\n", ack); 
    dprintf(1, "[O*] >%02X <%02X %d\n", byte, val, ack);
}



int main(int argc, char *argv[])
{
    int i;

    /* Get access to the ports */
    if (ioperm(FLOPPY, 8, 1)) { perror("ioperm"); exit(1); }

    /* initial state */
    out_dor(dor);

    usleep(5000);

    out_start();

    for (i=1; i<argc; i++)
	out_byte(strtol(argv[i], NULL, 16));

    out_stop();

    usleep(5000);


#if 0
    int i;

    for (i=0; i<64; i++) {

	/* Set the data signals (D0-7) of the port to all low (0) */
	outb(((i >> 2) << 4 | (i & 3)), FLOPPY_DOR);

	/* Sleep for a while (100 ms) */
	usleep(500000);

	/* Read from the status port (BASE+1) and display the result */
	printf("status: %d\n", inb(FLOPPY_DIR));

    }
#endif

    /* We don't need the ports anymore */
    if (ioperm(FLOPPY, 8, 0)) { perror("ioperm"); exit(1); }

    exit(0);
}