/* The printf is similar to printk.printk can be subsituted for printf
    in the below code. The code works upto some extent. When using the
    code while booting i can see the harddisk light blinking (red light) .
    So the controller is moving . But it is unable to read sectors
    somehow. Is the sequence correct for ide. It works correctly in vmware
    under linux(checked with hexdump /dev/hda in linux).But when tried to
    boot independently it causes error (atleast doesn't match with the
    correct data. It produces d0 1 d0 1 d0 1 d0 1 d0 1 d0 ...d9 1 d9 ...)
    which doesn't tally with hexdump /dev/hda.
    My guess is that sequence is not correct or i have made some error.So
    if someone experienced can tell me where the error is and make it work
    it would be very helpful in moving forward.
  */

static inline void
insw(unsigned short port, void *addr, unsigned long count)
{
    __asm__ __volatile__(" rep ; ins" "w":"=D"(addr),
			 "=c"(count):"d"(port), "0"(addr), "1"(count));
}

static int drive_busy(void)
{
    unsigned int i;
    unsigned char c;

    for (i = 0; i < 10000; i++)
	if (0x40 == (inb(0x1f7) & (0x80 | 0x40)))
	    break;

    i = inb(0x1f7);
    i &= 0x80 | 0x40 | 0x10;

    if (i == 0x40 | 0x10)
	return 0;

    printf("Hd controller times out\n");


}

void reset_controller(void)
{
    unsigned int i;
    outb(4, 0x3f6);

    for (i = 0; i < 1000; i++)
	__asm__ __volatile__("nop");

    outb(0, 0x3f6);

    for (i = 0; i < 10000 && drive_busy(); i++);

    if (drive_busy())
	printf("HD controller still busy\n");

    if (i = inb(0x1f1) != 1)
	printf("HD controller  reset  failed \n");

    if (!controller_ready())
	printf("HD controller not ready\n");
}

void
hd_out(unsigned int drive, unsigned char nsect, unsigned char
       sect, unsigned char head, unsigned char cyl, unsigned char cmd)
{
    unsigned short port;

    port = 0x1f0;
    ++port;

    outb(nsect, ++port);	/*1f2 */
    outb(sect, ++port);		/*1f3 */
    outb(cyl, ++port);		/*1f4 */
    outb(cyl >> 8, ++port);	/*1f5 */

    outb(0xA0 | (drive << 4), 0x1f6);
    outb(cmd, ++port);
}

void hd_init(void)
{
    unsigned char *s;
    unsigned int i = 0;

    hd_out(0, 2, 0, 0, 0, 0x10);
    hd_out(0, 2, 0, 0, 0, 0x20);

    insw(0x1f0, s, 10);

    for (i = 0; i < 10; i++)
	printf("%x\n", *(s + i));
}