/*	$NetBSD: disk.c,v 1.10 1995/01/18 15:46:34 mycroft Exp $	*/

/*
 * Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
 *
 * Mach Operating System
 * Copyright (c) 1992, 1991 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */

#include "boot.h"
#ifdef DO_BAD144
#include <sys/dkbad.h>
#endif DO_BAD144
#include <sys/disklabel.h>

#define	BIOS_DEV_FLOPPY	0x0
#define	BIOS_DEV_WIN	0x80

#define BPS		512
#define	SPT(di)		((di)&0xff)
#define	HEADS(di)	((((di)>>8)&0xff)+1)

char *devs[] = {"wd", "hd", "fd", "wt", "sd", 0};

#ifdef DO_BAD144
struct dkbad dkb;
int do_bad144;
int bsize;
#endif DO_BAD144

int spt, spc;

char *iodest;
struct fs *fs;
struct inode inode;
int dosdev, unit, part, maj, boff, poff, bnum, cnt;

/*#define EMBEDDED_DISKLABEL 1*/
extern struct disklabel disklabel;
/*struct	disklabel disklabel;*/

devopen()
{
	struct dos_partition *dptr;
	struct disklabel *dl;
	int i, sector, di;
	
	di = get_diskinfo(dosdev);
	spc = (spt = SPT(di)) * HEADS(di);
	if (dosdev == 2) {
		boff = 0;
		part = (spt == 15 ? 3 : 1);
	} else {
#ifdef	EMBEDDED_DISKLABEL
		dl = &disklabel;
#else	EMBEDDED_DISKLABEL
		Bread(0);
		dptr = (struct dos_partition *)(((char *)0)+DOSPARTOFF);
		sector = LABELSECTOR;
		for (i = 0; i < NDOSPART; i++, dptr++)
			if (dptr->dp_typ == DOSPTYP_386BSD) {
				sector = dptr->dp_start + LABELSECTOR;
				break;
			}
		Bread(sector++);
		dl=((struct disklabel *)0);
		disklabel = *dl;	/* structure copy (maybe useful later)*/
#endif	EMBEDDED_DISKLABEL
		if (dl->d_magic != DISKMAGIC) {
			printf("bad disklabel");
			return 1;
		}
		if( (maj == 4) || (maj == 0) || (maj == 1)) {
			if (dl->d_type == DTYPE_SCSI)
				maj = 4; /* use scsi as boot dev */
			else
				maj = 0; /* must be ESDI/IDE */
		}
		boff = dl->d_partitions[part].p_offset;
#ifdef DO_BAD144
		bsize = dl->d_partitions[part].p_size;
		do_bad144 = 0;
		if (dl->d_flags & D_BADSECT) {
			/* this disk uses bad144 */
			int i;
			int dkbbnum;
			struct dkbad *dkbptr;

			/* find the first readable bad144 sector */
			/* some of this code is copied from ufs_disksubr.c */
			/* read a bad sector table */
			dkbbnum = dl->d_secperunit - dl->d_nsectors;
			if (dl->d_secsize > DEV_BSIZE)
				dkbbnum *= dl->d_secsize / DEV_BSIZE;
			i = 0;
			do_bad144 = 0;
			do {
				/* XXX: what if the "DOS sector" < 512 bytes ??? */
				Bread(dkbbnum + i);
				dkbptr = (struct dkbad *) 0;
/* XXX why is this not in <sys/dkbad.h> ??? */
#define DKBAD_MAGIC 0x4321
				if (dkbptr->bt_mbz == 0 &&
				    dkbptr->bt_flag == DKBAD_MAGIC) {
					dkb = *dkbptr;	/* structure copy */
					do_bad144 = 1;
					break;
				}
				i += 2;
			} while (i < 10 && i < dl->d_nsectors);
			if (!do_bad144)
				printf("Bad badsect table\n");
			else
				printf("Using bad144 bad sector at %d\n",					    dkbbnum+i);
		}
#endif DO_BAD144
	}
	return 0;
}

devread()
{
	int offset, sector = bnum;
	for (offset = 0; offset < cnt; offset += BPS) {
		Bread(badsect(sector++));
		bcopy(0, iodest+offset, BPS);
	}
}

#define I_ADDR		((void *) 0)	/* XXX where all reads go */

/* Read ahead buffer large enough for one track on a 1440K floppy.  For
 * reading from floppies, the bootstrap has to be loaded on a 64K boundary
 * to ensure that this buffer doesn't cross a 64K DMA boundary.
 */
#define RA_SECTORS	18
static char ra_buf[RA_SECTORS * BPS];
static int ra_dev;
static int ra_end;
static int ra_first;

Bread(sector)
	int sector;
{
	if (dosdev != ra_dev || sector < ra_first || sector >= ra_end) {
		int cyl, head, sec, nsec;

		cyl = sector / spc;
		head = (sector % spc) / spt;
		sec = sector % spt;
		nsec = spt - sec;
		if (nsec > RA_SECTORS)
			nsec = RA_SECTORS;
		twiddle();
		if (biosread(dosdev, cyl, head, sec, nsec, ra_buf) != 0) {
			nsec = 1;
			twiddle();
			while (biosread(dosdev, cyl, head, sec, nsec, ra_buf) != 0) {
				printf("Error: C:%d H:%d S:%d\n", cyl, head, sec);
				twiddle();
			}
		}
		ra_dev = dosdev;
		ra_first = sector;
		ra_end = sector + nsec;
	}
	bcopy(ra_buf + (sector - ra_first) * BPS, I_ADDR, BPS);
}

badsect(sector)
	int sector;
{
	int i;
#ifdef DO_BAD144
	if (do_bad144) {
		u_short cyl, head, sec;
		int newsec;
		struct disklabel *dl = &disklabel;

		/* XXX */
		/* from wd.c */
		/* bt_cyl = cylinder number in sorted order */
		/* bt_trksec is actually (head << 8) + sec */

		/* only remap sectors in the partition */
		if (sector < boff || sector >= boff + bsize)
			goto no_remap;

		cyl = sector / dl->d_secpercyl;
		head = (sector % dl->d_secpercyl) / dl->d_nsectors;
		sec = sector % dl->d_nsectors;
		sec += head << 8;

		/* now, look in the table for a possible bad sector */
		for (i = 0; i < 126; i++) {
			if (dkb.bt_bad[i].bt_cyl == cyl &&
			    dkb.bt_bad[i].bt_trksec == sec) {
				/* found same sector */
				goto remap;
			} else if (dkb.bt_bad[i].bt_cyl > cyl) {
				goto no_remap;
			}
		}
		goto no_remap;
	remap:
		/* otherwise find replacement sector */
		newsec = dl->d_secperunit - dl->d_nsectors - i -1;
		return newsec;
	}
#endif DO_BAD144
no_remap:
	return sector;
}