/*
 * Morrow DJDMA
 */

#include "boot.h"


#define VERSO 0200		/* other side */
#define DJDRIVE 0		/* boot from drive 0 */
#define DJREAD 0x20
#define DJHALT 0x25
#define DJSETADDR 0x23
#define DJSTATE ((char *) 0xff00ef)
#define DJSUCCESS 0x40		/* status returned on successful operation */
#define DJBUSY 0
#define DJSTATUS 0x22
#define DJCHANNEL ((char *) 0x50)

/*
 * read a sector from the DJDMA
 * Return 0 on success, non-zero on failure.
 */

/*VARARGS*/
djread (cyl, head, sect, addr)
	int cyl, head, sect; 
	char *addr;
	{
	register char *p, *st;

	sect++;		/* 1-origin sector number correction */

	if (head)
		cyl |= VERSO;	/* other side */


	p = DJCHANNEL;

	*p++ = DJSETADDR;		/* set the dest. address */
	*p++ = lobyte(addr);
	*p++ = midbyte(addr);
	*p++ = hibyte(addr);

	*p++ = DJREAD;
	*p++ = cyl;	/* cylinder and head */
	*p++ = sect;	/* sector */
	*p++ = DJDRIVE;	/* drive */
	*(st = p++) = DJBUSY;	/* return status */

	*p++ = DJHALT;

	run (DJSTATE, p);

	return *st != DJSUCCESS;
	}

/*
 * Initialize the Morrow DJDMA
 */

#define DJLOGICAL 0x2e
#define FIVEFIRST 4
#define EIGHTFIRST 0

djopen ()
	{
	register char *p, *st;

	p = DJCHANNEL;

	*p++ = DJLOGICAL;
	*p++ = FIVEFIRST;
	*p++ = DJBUSY;

	*p++ = DJSTATUS;		/* djdma status */
	*p++ = DJDRIVE;
	*p++ = DJBUSY;
	*p++ = DJBUSY;
	*p++ = DJBUSY;
	*(st = p++) = DJBUSY;

	*p++ = DJHALT;
	run (DJSTATE, p);

	if (*st == DJSUCCESS)
		return 0;

/*
 * Try the 8" drive
 */


	p = DJCHANNEL;
		
	*p++ = DJLOGICAL;
	*p++ = EIGHTFIRST;
	*p++ = DJBUSY;

	*p++ = DJSTATUS;		/* djdma status */
	*p++ = DJDRIVE;
	*p++ = DJBUSY;
	*p++ = DJBUSY;
	*p++ = DJBUSY;
	*(st = p++) = DJBUSY;

	*p++ = DJHALT;
	run (DJSTATE, p);

	if (*st == DJSUCCESS)
		return 0;

	return -1;
	}