[unix-history] / sys / i386 / isa / wd.c

#define WD_COUNT_RETRIES
static int wdtest = 0;

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	from: @(#)wd.c	7.2 (Berkeley) 5/9/91
 *	$Id: wd.c,v 1.36 1994/03/06 03:10:58 jkh Exp $
 */

/* TODO:
 *	o Bump error count after timeout.
 *	o Satisfy ATA timing in all cases.
 *	o Finish merging berry/sos timeout code (bump error count...).
 *	o Merge/fix TIH/NetBSD bad144 code.
 *	o Merge/fix Dyson/NetBSD clustering code.
 *	o Don't use polling except for initialization.  Need to
 *	  reorganize the state machine.  Then "extra" interrupts
 *	  shouldn't happen (except maybe one for initialization).
 *	o Fix disklabel, boot and driver inconsistencies with
 *	  bad144 in standard versions.
 *	o Support extended DOS partitions.
 *	o Support swapping to DOS partitions.
 *	o Look at latest linux clustering methods.  Our disksort()
 *	  gets in the way of clustering.
 *	o Handle bad sectors, clustering, disklabelling, DOS
 *	  partitions and swapping driver-independently.  Use
 *	  i386/dkbad.c for bad sectors.  Swapping will need new
 *	  driver entries for polled reinit and polled write).
 */

#include "wd.h"
#if	NWDC > 0

#include "param.h"
#include "dkbad.h"
#include "systm.h"
#include "kernel.h"
#include "conf.h"
#include "file.h"
#include "stat.h"
#include "ioctl.h"
#include "disklabel.h"
#include "buf.h"
#include "uio.h"
#include "malloc.h"
#include "machine/cpu.h"
#include "i386/isa/isa.h"
#include "i386/isa/isa_device.h"
#include "i386/isa/wdreg.h"
#include "syslog.h"
#include "vm/vm.h"

#define	TIMEOUT		10000	/* XXX? WDCC_DIAGNOSE can take > 1.1 sec */

#define	RETRIES		5	/* number of retries before giving up */
#define RECOVERYTIME	500000	/* usec for controller to recover after err */
#define	MAXTRANSFER	256	/* max size of transfer in sectors */

#ifdef notyet
#define wdnoreloc(dev)	(minor(dev) & 0x80)	/* ignore partition table */
#endif
#define wddospart(dev)	(minor(dev) & 0x40)	/* use dos partitions */
#define wdunit(dev)	((minor(dev) & 0x38) >> 3)
#define wdpart(dev)	(minor(dev) & 0x7)
#define makewddev(maj, unit, part)	(makedev(maj,((unit<<3)+part)))
#define WDRAW	3		/* 'd' partition isn't a partition! */

/* Cylinder number for doing IO to.  Shares an entry in the buf struct. */
#define b_cylin	b_resid

/*
 * This biotab field doubles as a field for the physical unit number on
 * the controller.
 */
#define	id_physid id_scsiid

/*
 * Drive states.  Used to initialize drive.
 */

#define	CLOSED		0	/* disk is closed. */
#define	WANTOPEN	1	/* open requested, not started */
#define	RECAL		2	/* doing restore */
#define	OPEN		3	/* done with open */

/*
 * The structure of a disk drive.
 */
struct disk {
	long	dk_bc;		/* byte count left */
	short	dk_skip;	/* blocks already transferred */
	char	dk_ctrlr;	/* physical controller number */
	char	dk_unit;	/* physical unit number */
	char	dk_lunit;	/* logical unit number */
	char	dk_state;	/* control state */
	u_char	dk_status;	/* copy of status reg. */
	u_char	dk_error;	/* copy of error reg. */
	u_char	dk_timeout;	/* countdown to next timeout */
	short	dk_port;	/* i/o port base */

	u_long  dk_copenpart;	/* character units open on this drive */
	u_long  dk_bopenpart;	/* block units open on this drive */
	u_long  dk_openpart;	/* all units open on this drive */
	short	dk_wlabel;	/* label writable? */
	short	dk_flags;	/* drive characteistics found */
#define	DKFL_DOSPART	0x00001	/* has DOS partition table */
#define	DKFL_SINGLE	0x00004	/* sector at a time mode */
#define	DKFL_ERROR	0x00008	/* processing a disk error */
#define	DKFL_BSDLABEL	0x00010	/* has a BSD disk label */
#define	DKFL_BADSECT	0x00020	/* has a bad144 badsector table */
#define	DKFL_WRITEPROT	0x00040	/* manual unit write protect */
#define	DKFL_LABELLING	0x00080	/* readdisklabel() in progress */
	struct wdparams dk_params; /* ESDI/IDE drive/controller parameters */
	struct disklabel dk_dd;	/* device configuration data */
	struct disklabel dk_dd2;	/* DOS view converted to label */
	struct dos_partition
		dk_dospartitions[NDOSPART];	/* DOS view of disk */
	struct dkbad dk_bad;	/* bad sector table */
};

static struct disk *wddrives[NWD];	/* table of units */
static struct buf wdtab[NWDC];
static struct buf wdutab[NWD];	/* head of queue per drive */
#ifdef notyet
static struct buf rwdbuf[NWD];	/* buffers for raw IO */
#endif
static long wdxfer[NWD];	/* count of transfers */

static int wdprobe(struct isa_device *dvp);
static int wdattach(struct isa_device *dvp);
static void wdustart(struct disk *du);
static void wdstart(int ctrlr);
static int wdcontrol(struct buf *bp);
static int wdcommand(struct disk *du, u_int cylinder, u_int head,
		     u_int sector, u_int count, u_int command);
static int wdsetctlr(struct disk *du);
static int wdwsetctlr(struct disk *du);
static int wdgetctlr(struct disk *du);
static void wderror(struct buf *bp, struct disk *du, char *mesg);
static void wdflushirq(struct disk *du, int old_ipl);
static int wdreset(struct disk *du);
static void wdsleep(int ctrlr, char *wmesg);
static void wdtimeout(caddr_t cdu, int ticks);
static int wdunwedge(struct disk *du);
static int wdwait(struct disk *du, u_char bits_wanted, int timeout);

struct isa_driver wdcdriver = {
	wdprobe, wdattach, "wdc",
};

/*
 * Probe for controller.
 */
static int
wdprobe(struct isa_device *dvp)
{
	int	unit = dvp->id_unit;
	struct disk *du;

	if (unit >= NWDC)
		return (0);
	du = malloc(sizeof *du, M_TEMP, M_NOWAIT);
	if (du == NULL)
		return (0);
	bzero(du, sizeof *du);
	du->dk_ctrlr = dvp->id_unit;
	du->dk_port = dvp->id_iobase;

	/* check if we have registers that work */
	outb(du->dk_port + wd_cyl_lo, 0xa5);	/* wd_cyl_lo is read/write */
	if (inb(du->dk_port + wd_cyl_lo) != 0xa5)
		goto nodevice;

	if (wdreset(du) != 0 && (DELAY(RECOVERYTIME), wdreset(du)) != 0)
		goto nodevice;

	/* execute a controller only command */
	if (wdcommand(du, 0, 0, 0, 0, WDCC_DIAGNOSE) != 0
	    || wdwait(du, 0, TIMEOUT) != 0)
		goto nodevice;

	free(du, M_TEMP);
	return (IO_WDCSIZE);

nodevice:
	free(du, M_TEMP);
	return (0);
}

/*
 * Attach each drive if possible.
 */
static int
wdattach(struct isa_device *dvp)
{
	int	unit, lunit;
	struct isa_device *wdup;
	struct disk *du;

	if (dvp->id_unit >= NWDC)
		return (0);

	for (wdup = isa_biotab_wdc; wdup->id_driver != 0; wdup++) {
		if (wdup->id_iobase != dvp->id_iobase)
			continue;
		lunit = wdup->id_unit;
		if (lunit >= NWD)
			continue;
		unit = wdup->id_physid;

		du = malloc(sizeof *du, M_TEMP, M_NOWAIT);
		if (du == NULL)
			continue;
		if (wddrives[lunit] != NULL)
			panic("drive attached twice");
		wddrives[lunit] = du;
		bzero(du, sizeof *du);
		du->dk_ctrlr = dvp->id_unit;
		du->dk_unit = unit;
		du->dk_lunit = lunit;
		du->dk_port = dvp->id_iobase;

		/*
		 * Print out description of drive.
		 * wdp_model can be [0..40] bytes, thus \0 can be missing so
		 * so copy it and add a null before printing.
		 */
		if (wdgetctlr(du) == 0) {
		    char buf[sizeof(du->dk_params.wdp_model) + 1];
		    bcopy(du->dk_params.wdp_model, buf, sizeof(buf)-1);
		    buf[sizeof(buf)-1] = '\0';
		    printf("wdc%d: unit %d (wd%d): <%s>\n",
			dvp->id_unit, unit, lunit, buf);
		    if (du->dk_params.wdp_heads == 0)
			printf("wd%d: size unknown\n", lunit);
		    else
			printf("wd%d: %luMB (%lu total sec), ",
				lunit,
				du->dk_dd.d_secperunit
				* du->dk_dd.d_secsize / (1024 * 1024),
				du->dk_dd.d_secperunit);
			printf("%lu cyl, %lu head, %lu sec, bytes/sec %lu\n",
				du->dk_dd.d_ncylinders,
				du->dk_dd.d_ntracks,
				du->dk_dd.d_nsectors,
				du->dk_dd.d_secsize);
			/*
			 * Start timeout routine for this drive.
			 * XXX timeout should be per controller.
			 */
			wdtimeout((caddr_t)du, 0);
		} else {
			free(du, M_TEMP);
			wddrives[lunit] = NULL;
		}
	}

	/*
	 * Discard any interrupts generated by wdgetctlr().  wdflushirq()
	 * doesn't work now because the ambient ipl is too high.
	 */
	wdtab[dvp->id_unit].b_active = 2;

	return (1);
}

/* Read/write routine for a buffer.  Finds the proper unit, range checks
 * arguments, and schedules the transfer.  Does not wait for the transfer
 * to complete.  Multi-page transfers are supported.  All I/O requests must
 * be a multiple of a sector in length.
 */
void
wdstrategy(register struct buf *bp)
{
	register struct buf *dp;
	struct disk *du;
	int	lunit = wdunit(bp->b_dev);
	int	s;

	/* valid unit, controller, and request?  */
	if (lunit >= NWD || bp->b_blkno < 0 || (du = wddrives[lunit]) == NULL) {

		bp->b_error = EINVAL;
		bp->b_flags |= B_ERROR;
		goto done;
	}

	/* "soft" write protect check */
	if ((du->dk_flags & DKFL_WRITEPROT) && (bp->b_flags & B_READ) == 0) {
		bp->b_error = EROFS;
		bp->b_flags |= B_ERROR;
		goto done;
	}

	/*
	 * Do bounds checking, adjust transfer, and set b_cylin.
	 */
	if (bounds_check_with_label(bp, wddospart(bp->b_dev)
					? &du->dk_dd2 : &du->dk_dd,
				    du->dk_wlabel) <= 0)
		goto done;

	/* queue transfer on drive, activate drive and controller if idle */
	dp = &wdutab[lunit];
	s = splbio();
	disksort(dp, bp);
	if (dp->b_active == 0)
		wdustart(du);	/* start drive */

	/* Pick up changes made by readdisklabel(). */
	if (du->dk_flags & DKFL_LABELLING && du->dk_state > RECAL) {
		wdsleep(du->dk_ctrlr, "wdlab");
		du->dk_state = WANTOPEN;
	}

	if (wdtab[du->dk_ctrlr].b_active == 0)
		wdstart(du->dk_ctrlr);	/* start controller */
	splx(s);
	return;

done:
	/* toss transfer, we're done early */
	biodone(bp);
}

/*
 * Routine to queue a command to the controller.  The unit's
 * request is linked into the active list for the controller.
 * If the controller is idle, the transfer is started.
 */
static void
wdustart(register struct disk *du)
{
	register struct buf *bp, *dp = &wdutab[du->dk_lunit];
	int	ctrlr = du->dk_ctrlr;

	/* unit already active? */
	if (dp->b_active)
		return;

	/* anything to start? */
	bp = dp->b_actf;
	if (bp == NULL)
		return;

	/* link onto controller queue */
	dp->b_forw = NULL;
	if (wdtab[ctrlr].b_actf == NULL)
		wdtab[ctrlr].b_actf = dp;
	else
		wdtab[ctrlr].b_actl->b_forw = dp;
	wdtab[ctrlr].b_actl = dp;

	/* mark the drive unit as busy */
	dp->b_active = 1;
}

/*
 * Controller startup routine.  This does the calculation, and starts
 * a single-sector read or write operation.  Called to start a transfer,
 * or from the interrupt routine to continue a multi-sector transfer.
 * RESTRICTIONS:
 * 1. The transfer length must be an exact multiple of the sector size.
 */

static void
wdstart(int ctrlr)
{
	register struct disk *du;
	register struct buf *bp;
	struct disklabel *lp;
	struct buf *dp;
	register struct bt_bad *bt_ptr;
	long	blknum, cylin, head, sector;
	long	secpertrk, secpercyl;
	int	lunit;

loop:
	/* is there a drive for the controller to do a transfer with? */
	dp = wdtab[ctrlr].b_actf;
	if (dp == NULL)
		return;

	/*
	 * Is there a transfer to this drive?  If so, link it on the
	 * controller's queue.
	 */
	bp = dp->b_actf;
	if (bp == NULL) {
		wdtab[ctrlr].b_actf = dp->b_forw;
		goto loop;
	}

	/* obtain controller and drive information */
	lunit = wdunit(bp->b_dev);
	du = wddrives[lunit];

	/* if not really a transfer, do control operations specially */
	if (du->dk_state < OPEN) {
		if (du->dk_state != WANTOPEN)
			printf("wd%d: wdstart: weird dk_state %d\n",
			       du->dk_lunit, du->dk_state);
		if (wdcontrol(bp) != 0)
			printf("wd%d: wdstart: wdcontrol returned nonzero, state = %d\n",
			       du->dk_lunit, du->dk_state);
		return;
	}

	/* calculate transfer details */
	blknum = bp->b_blkno + du->dk_skip;
#ifdef WDDEBUG
	if (du->dk_skip == 0)
		printf("wd%d: wdstart: %s %d@%d; map ", lunit,
		       (bp->b_flags & B_READ) ? "read" : "write",
		       bp->b_bcount, blknum);
	else
		printf(" %d)%x", du->dk_skip, inb(du->dk_port + wd_altsts));
#endif
	if (du->dk_skip == 0)
		du->dk_bc = bp->b_bcount;

	lp = &du->dk_dd;
	secpertrk = lp->d_nsectors;
	secpercyl = lp->d_secpercyl;
	if (wddospart(bp->b_dev))
		blknum += du->dk_dd2.d_partitions[wdpart(bp->b_dev)].p_offset;
	else
		blknum += lp->d_partitions[wdpart(bp->b_dev)].p_offset;
	cylin = blknum / secpercyl;
	head = (blknum % secpercyl) / secpertrk;
	sector = blknum % secpertrk;

	/* 
	 * See if the current block is in the bad block list.
	 * (If we have one, and not formatting.)
	 */
	if ((du->dk_flags & (DKFL_SINGLE | DKFL_BADSECT))
	    == (DKFL_SINGLE | DKFL_BADSECT))
#define BAD144_NO_CYL	0xffff	/* XXX should be in dkbad.h; bad144.c uses -1 */
	    for (bt_ptr = du->dk_bad.bt_bad; bt_ptr->bt_cyl != BAD144_NO_CYL;
		 bt_ptr++) {
		if (bt_ptr->bt_cyl > cylin)
			/* Sorted list, and we passed our cylinder. quit. */
			break;
		if (bt_ptr->bt_cyl == cylin &&
		    bt_ptr->bt_trksec == (head << 8) + sector) {
			/*
			 * Found bad block.  Calculate new block number.
			 * This starts at the end of the disk (skip the
			 * last track which is used for the bad block list),
			 * and works backwards to the front of the disk.
			 */
#ifdef WDDEBUG
			printf("--- badblock code -> Old = %ld; ", blknum);
#endif

			/*
			 * XXX the offset of the bad sector table ought
			 * to be stored in the in-core copy of the table.
			 */
#define BAD144_PART	2	/* XXX scattered magic numbers */
#define BSD_PART	0	/* XXX should be 2 but bad144.c uses 0 */
			if (lp->d_partitions[BSD_PART].p_offset != 0)
				blknum = lp->d_partitions[BAD144_PART].p_offset
					 + lp->d_partitions[BAD144_PART].p_size;
			else
				blknum = lp->d_secperunit;
			blknum -= lp->d_nsectors + (bt_ptr - du->dk_bad.bt_bad)
				  + 1;

			cylin = blknum / secpercyl;
			head = (blknum % secpercyl) / secpertrk;
			sector = blknum % secpertrk;
#ifdef WDDEBUG
			printf("new = %ld\n", blknum);
#endif
			break;
		}
	}

	wdtab[ctrlr].b_active = 1;	/* mark controller active */

	/* if starting a multisector transfer, or doing single transfers */
	if (du->dk_skip == 0 || (du->dk_flags & DKFL_SINGLE)) {
		u_int	command;
		u_int	count;

		if (wdtab[ctrlr].b_errcnt && (bp->b_flags & B_READ) == 0)
			du->dk_bc += DEV_BSIZE;

#ifdef B_FORMAT
		if (bp->b_flags & B_FORMAT) {
			command = WDCC_FORMAT;
			count = lp->d_nsectors;
			sector = lp->d_gap3 - 1;	/* + 1 later */
		} else
#endif
		{
			if (du->dk_flags & DKFL_SINGLE)
				count = 1;
			else
				count = howmany(du->dk_bc, DEV_BSIZE);
			command = (bp->b_flags & B_READ)
				  ? WDCC_READ : WDCC_WRITE;
		}

		/*
		 * XXX this loop may never terminate.  The code to handle
		 * counting down of retries and eventually failing the i/o
		 * is in wdintr() and we can't get there from here.
		 */
		if (wdtest != 0) {
			if (--wdtest == 0) {
				wdtest = 100;
				printf("dummy wdunwedge\n");
				wdunwedge(du);
			}
		}
		while (wdcommand(du, cylin, head, sector, count, command)
		       != 0) {
			wderror(bp, du,
				"wdstart: timeout waiting to give command");
			wdunwedge(du);
		}
#ifdef WDDEBUG
		printf("cylin %ld head %ld sector %ld addr %x sts %x\n",
		       cylin, head, sector,
		       (int)bp->b_un.b_addr + du->dk_skip * DEV_BSIZE,
		       inb(du->dk_port + wd_altsts));
#endif
	}

	/*
	 * Schedule wdtimeout() to wake up after a few seconds.  Retrying
	 * unmarked bad blocks can take 3 seconds!  Then it is not good that
	 * we retry 5 times.
	 *
	 * XXX wdtimeout() doesn't increment the error count so we may loop
	 * forever.  More seriously, the loop isn't forever but causes a
	 * crash.
	 *
	 * TODO fix b_resid bug elsewhere (fd.c....).  Fix short but positive
	 * counts being discarded after there is an error (in physio I
	 * think).  Discarding them would be OK if the (special) file offset
	 * was not advanced.
	 */
	du->dk_timeout = 1 + 3;

	/* If this is a read operation, just go away until it's done. */
	if (bp->b_flags & B_READ)
		return;

	/* Ready to send data? */
	if (wdwait(du, WDCS_READY | WDCS_SEEKCMPLT | WDCS_DRQ, TIMEOUT) < 0) {
		wderror(bp, du, "wdstart: timeout waiting for DRQ");
		/*
		 * XXX what do we do now?  If we've just issued the command,
		 * then we can treat this failure the same as a command
		 * failure.  But if we are continuing a multi-sector write,
		 * the command was issued ages ago, so we can't simply
		 * restart it.
		 *
		 * XXX we waste a lot of time unnecessarily translating block
		 * numbers to cylin/head/sector for continued i/o's.
		 */
	}

	/* then send it! */
	outsw(du->dk_port + wd_data,
	      (void *)((int)bp->b_un.b_addr + du->dk_skip * DEV_BSIZE),
	      DEV_BSIZE / sizeof(short));
	du->dk_bc -= DEV_BSIZE;
}

/* Interrupt routine for the controller.  Acknowledge the interrupt, check for
 * errors on the current operation, mark it done if necessary, and start
 * the next request.  Also check for a partially done transfer, and
 * continue with the next chunk if so.
 */
void
wdintr(int unit)
{
	register struct	disk *du;
	register struct buf *bp, *dp;

	if (wdtab[unit].b_active == 2)
		return;		/* intr in wdflushirq() */
	if (!wdtab[unit].b_active) {
#ifndef LAPTOP
		printf("wdc%d: extra interrupt\n", unit);
#endif
		return;
	}

	dp = wdtab[unit].b_actf;
	bp = dp->b_actf;
	du = wddrives[wdunit(bp->b_dev)];
	du->dk_timeout = 0;

	if (wdwait(du, 0, TIMEOUT) < 0) {
		wderror(bp, du, "wdintr: timeout waiting for status");
		du->dk_status |= WDCS_ERR;	/* XXX */
	}

	/* is it not a transfer, but a control operation? */
	if (du->dk_state < OPEN) {
		wdtab[unit].b_active = 0;
		switch (wdcontrol(bp)) {
		case 0:
			return;
		case 1:
			wdstart(unit);
		return;
		case 2:
			goto done;
		}
	}

	/* have we an error? */
	if (du->dk_status & (WDCS_ERR | WDCS_ECCCOR)) {
oops:
#ifdef WDDEBUG
		wderror(bp, du, "wdintr");
#endif
		if ((du->dk_flags & DKFL_SINGLE) == 0) {
			du->dk_flags |= DKFL_ERROR;
			goto outt;
		}
#ifdef B_FORMAT
		if (bp->b_flags & B_FORMAT) {
			bp->b_error = EIO;
			bp->b_flags |= B_ERROR;
			goto done;
		}
#endif

		/* error or error correction? */
		if (du->dk_status & WDCS_ERR) {
			if (++wdtab[unit].b_errcnt < RETRIES) {
				wdtab[unit].b_active = 0;
			} else {
				wderror(bp, du, "hard error");
				bp->b_error = EIO;
				bp->b_flags |= B_ERROR;	/* flag the error */
			}
		} else
			wderror(bp, du, "soft ecc");
	}

	/*
	 * If this was a successful read operation, fetch the data.
	 */
	if (((bp->b_flags & (B_READ | B_ERROR)) == B_READ)
	    && wdtab[unit].b_active) {
		int	chk, dummy;

		chk = min(DEV_BSIZE / sizeof(short), du->dk_bc / sizeof(short));

		/* ready to receive data? */
		if (wdwait(du, WDCS_READY | WDCS_SEEKCMPLT | WDCS_DRQ, TIMEOUT) != 0) {
			wderror(bp, du, "wdintr: read error detected late");
			goto oops;
		}

		/* suck in data */
		insw(du->dk_port + wd_data,
		     (void *)((int)bp->b_un.b_addr + du->dk_skip * DEV_BSIZE),
				chk);
		du->dk_bc -= chk * sizeof(short);

		/* XXX for obsolete fractional sector reads. */
		while (chk++ < DEV_BSIZE / sizeof(short))
			insw(du->dk_port + wd_data, &dummy, 1);
	}

	wdxfer[du->dk_lunit]++;
outt:
	if (wdtab[unit].b_active) {
		if ((bp->b_flags & B_ERROR) == 0) {
			du->dk_skip++;	/* add to successful sectors */
			if (wdtab[unit].b_errcnt)
				wderror(bp, du, "soft error");
			wdtab[unit].b_errcnt = 0;

			/* see if more to transfer */
			if (du->dk_bc > 0 && (du->dk_flags & DKFL_ERROR) == 0) {
				wdtab[unit].b_active = 0;
				wdstart(unit);
				return;	/* next chunk is started */
			} else if ((du->dk_flags & (DKFL_SINGLE | DKFL_ERROR))
				   == DKFL_ERROR) {
				du->dk_skip = 0;
				du->dk_flags &= ~DKFL_ERROR;
				du->dk_flags |= DKFL_SINGLE;
				wdtab[unit].b_active = 0;
				wdstart(unit);
				return;	/* redo xfer sector by sector */
			}
		}

done: ;
		/* done with this transfer, with or without error */
		du->dk_flags &= ~DKFL_SINGLE;
		wdtab[unit].b_actf = dp->b_forw;
		wdtab[unit].b_errcnt = 0;
		bp->b_resid = bp->b_bcount - du->dk_skip * DEV_BSIZE;
		du->dk_skip = 0;
		dp->b_active = 0;
		dp->b_actf = bp->av_forw;
		dp->b_errcnt = 0;
		biodone(bp);
	}

	/* controller idle */
	wdtab[unit].b_active = 0;

	/* anything more on drive queue? */
	if (dp->b_actf)
		wdustart(du);
	/* anything more for controller to do? */
	if (wdtab[unit].b_actf)
		wdstart(unit);
}

/*
 * Initialize a drive.
 */
int
wdopen(dev_t dev, int flags, int fmt, struct proc *p)
{
	register unsigned int lunit;
	register struct disk *du;
	int	part = wdpart(dev), mask = 1 << part;
	struct partition *pp;
	char	*msg;
	struct disklabel save_label;

	lunit = wdunit(dev);
	if (lunit >= NWD)
		return (ENXIO);
	du = wddrives[lunit];
	if (du == NULL)
		return (ENXIO);

	/* Finish flushing IRQs left over from wdattach(). */
	if (wdtab[du->dk_ctrlr].b_active == 2)
		wdtab[du->dk_ctrlr].b_active = 0;

	/*
	 * That's all for valid DOS partitions.  We don't need a BSD label.
	 * The openmask is only used for checking BSD partitions so we don't
	 * need to maintain it.
	 */
	if (wddospart(dev)) {
		/* XXX we do need a disklabel for now. */
		if ((du->dk_flags & DKFL_BSDLABEL) == 0)
			return (ENXIO);

		return (part > NDOSPART ? ENXIO : 0);
	}

	while (du->dk_flags & DKFL_LABELLING)
		tsleep((caddr_t)&du->dk_flags, PZERO - 1, "wdopen", 1);
	if ((du->dk_flags & DKFL_BSDLABEL) == 0) {
		/*
		 * wdtab[ctrlr].b_active != 0 implies
		 * wdutab[lunit].b_actf == NULL (?)
		 * so the following guards most things (until the next i/o).
		 * It doesn't guard against a new i/o starting and being
		 * affected by the label being changed.  Sigh.
		 */
		wdsleep(du->dk_ctrlr, "wdopn1");

		du->dk_flags |= DKFL_LABELLING | DKFL_WRITEPROT;
		du->dk_state = WANTOPEN;
		wdutab[lunit].b_actf = NULL;

		/*
		 * Read label using WDRAW partition.
		 *
		 * If the drive has an MBR, then the current geometry (from
		 * wdgetctlr()) is used to read it; then the BIOS/DOS
		 * geometry is inferred and used to read the label off the
		 * 'c' partition.  Otherwise the label is read using the
		 * current geometry.  The label gives the final geometry.
		 * If bad sector handling is enabled, then this geometry
		 * is used to read the bad sector table.  The geometry
		 * changes occur inside readdisklabel() and are propagated
		 * to the driver by resetting the state machine.
		 */
		save_label = du->dk_dd;
#define WDSTRATEGY	((int (*)(struct buf *)) wdstrategy)	/* XXX */
		msg = readdisklabel(makewddev(major(dev), lunit, WDRAW),
				    (d_strategy_t *) WDSTRATEGY, &du->dk_dd,
				    du->dk_dospartitions, &du->dk_bad,
				    (struct buf **)NULL);
		du->dk_flags &= ~DKFL_LABELLING;
		if (msg != NULL) {
			du->dk_dd = save_label;
			log(LOG_WARNING, "wd%d: cannot find label (%s)\n",
			    lunit, msg);
			if (part != WDRAW)
				return (EINVAL);  /* XXX needs translation */
		} else {
			int	dospart;
			unsigned long newsize, offset, size;

			du->dk_flags |= DKFL_BSDLABEL;
			du->dk_flags &= ~DKFL_WRITEPROT;
			if (du->dk_dd.d_flags & D_BADSECT)
				du->dk_flags |= DKFL_BADSECT;

			/*
			 * Force WDRAW partition to be the whole disk.
			 */
			offset = du->dk_dd.d_partitions[WDRAW].p_offset;
			if (offset != 0) {
				printf(
		"wd%d: changing offset of 'd' partition from %lu to 0\n",
				       du->dk_lunit, offset);
				du->dk_dd.d_partitions[WDRAW].p_offset = 0;
			}
			size = du->dk_dd.d_partitions[WDRAW].p_size;
			newsize = du->dk_dd.d_secperunit;	/* XXX */
			if (size != newsize) {
				printf(
		"wd%d: changing size of 'd' partition from %lu to %lu\n",
				       du->dk_lunit, size, newsize);
				du->dk_dd.d_partitions[WDRAW].p_size = newsize;
			}

			/*
			 * Convert DOS partition data to a label.
			 */
			du->dk_dd2 = du->dk_dd;
			bzero(du->dk_dd2.d_partitions,
			      sizeof du->dk_dd2.d_partitions);
			du->dk_dd2.d_partitions[0].p_size
			    = du->dk_dd.d_secperunit;	/* XXX */
			for (dospart = 1; dospart <= NDOSPART; dospart++) {
				du->dk_dd2.d_partitions[dospart].p_offset =
				    du->dk_dospartitions[dospart - 1].dp_start;
				du->dk_dd2.d_partitions[dospart].p_size =
				    du->dk_dospartitions[dospart - 1].dp_size;
			}
		}

		/* Pick up changes made by readdisklabel(). */
		wdsleep(du->dk_ctrlr, "wdopn2");
		du->dk_state = WANTOPEN;
	}

	/*
	 * Warn if a partion is opened that overlaps another partition which
	 * is open unless one is the "raw" partition (whole disk).
	 */
	if ((du->dk_openpart & mask) == 0 && part != WDRAW) {
		int	start, end;

		pp = &du->dk_dd.d_partitions[part];
		start = pp->p_offset;
		end = pp->p_offset + pp->p_size;
		for (pp = du->dk_dd.d_partitions;
		     pp < &du->dk_dd.d_partitions[du->dk_dd.d_npartitions];
		     pp++) {
			if (pp->p_offset + pp->p_size <= start ||
			    pp->p_offset >= end)
				continue;
			if (pp - du->dk_dd.d_partitions == WDRAW)
				continue;
			if (du->dk_openpart
			    & (1 << (pp - du->dk_dd.d_partitions)))
				log(LOG_WARNING,
				    "wd%d%c: overlaps open partition (%c)\n",
				    lunit, part + 'a',
				    pp - du->dk_dd.d_partitions + 'a');
		}
	}
	if (part >= du->dk_dd.d_npartitions && part != WDRAW)
		return (ENXIO);

	switch (fmt) {
	case S_IFCHR:
		du->dk_copenpart |= mask;
		break;
	case S_IFBLK:
		du->dk_bopenpart |= mask;
		break;
	}
	du->dk_openpart = du->dk_copenpart | du->dk_bopenpart;

	return (0);
}

/*
 * Implement operations other than read/write.
 * Called from wdstart or wdintr during opens and formats.
 * Uses finite-state-machine to track progress of operation in progress.
 * Returns 0 if operation still in progress, 1 if completed, 2 if error.
 */
static int
wdcontrol(register struct buf *bp)
{
	register struct disk *du;
	int	ctrlr;

	du = wddrives[wdunit(bp->b_dev)];
	ctrlr = du->dk_ctrlr;

	switch (du->dk_state) {
	case WANTOPEN:
tryagainrecal:
		wdtab[ctrlr].b_active = 1;
		if (wdcommand(du, 0, 0, 0, 0, WDCC_RESTORE | WD_STEP) != 0) {
			wderror(bp, du, "wdcontrol: wdcommand failed");
			goto maybe_retry;
		}
		du->dk_state = RECAL;
		return (0);
	case RECAL:
		if (du->dk_status & WDCS_ERR || wdsetctlr(du) != 0) {
			wderror(bp, du, "wdcontrol: recal failed");
maybe_retry:
			if (du->dk_status & WDCS_ERR)
				wdunwedge(du);
			du->dk_state = WANTOPEN;
			if (++wdtab[ctrlr].b_errcnt < RETRIES)
				goto tryagainrecal;
			bp->b_error = ENXIO;	/* XXX needs translation */
			bp->b_flags |= B_ERROR;
			return (2);
		}
		wdtab[ctrlr].b_errcnt = 0;
		du->dk_state = OPEN;
		/*
		 * The rest of the initialization can be done by normal
		 * means.
		 */
		return (1);
	}
	panic("wdcontrol");
	return (2);
}

/*
 * Wait uninterruptibly until controller is not busy, then send it a command.
 * The wait usually terminates immediately because we waited for the previous
 * command to terminate.
 */
static int
wdcommand(struct disk *du, u_int cylinder, u_int head, u_int sector,
	  u_int count, u_int command)
{
	u_int	wdc;

	if (wdwait(du, 0, TIMEOUT) < 0)
		return (1);
	wdc = du->dk_port;
	outb(wdc + wd_precomp, du->dk_dd.d_precompcyl / 4);
	outb(wdc + wd_cyl_lo, cylinder);
	outb(wdc + wd_cyl_hi, cylinder >> 8);
	outb(wdc + wd_sdh, WDSD_IBM | (du->dk_unit << 4) | head);
	outb(wdc + wd_sector, sector + 1);
	outb(wdc + wd_seccnt, count);
	if (wdwait(du, command == WDCC_DIAGNOSE || command == WDCC_IDC
		       ? 0 : WDCS_READY, TIMEOUT) < 0)
		return (1);
	outb(wdc + wd_command, command);
	return (0);
}

/*
 * issue IDC to drive to tell it just what geometry it is to be.
 */
static int
wdsetctlr(struct disk *du)
{
#ifdef WDDEBUG
	printf("wd(%d,%d): wdsetctlr: C %lu H %lu S %lu\n",
	       du->dk_ctrlr, du->dk_unit,
	       du->dk_dd.d_ncylinders, du->dk_dd.d_ntracks,
	       du->dk_dd.d_nsectors);
#endif
	if (du->dk_dd.d_ntracks == 0 || du->dk_dd.d_ntracks > 16) {
		struct wdparams *wp;

		printf("wd%d: can't handle %lu heads from partition table ",
		       du->dk_lunit, du->dk_dd.d_ntracks);
		/* obtain parameters */
		wp = &du->dk_params;
		if (wp->wdp_heads > 0 && wp->wdp_heads <= 16) {
			printf("(controller value %lu restored)\n",
				wp->wdp_heads);
			du->dk_dd.d_ntracks = wp->wdp_heads;
		}
		else {
			printf("(truncating to 16)\n");
		du->dk_dd.d_ntracks = 16;
	}
	}
	if (wdcommand(du, du->dk_dd.d_ncylinders, du->dk_dd.d_ntracks - 1, 0,
		      du->dk_dd.d_nsectors, WDCC_IDC) != 0
	    || wdwait(du, WDCS_READY, TIMEOUT) < 0) {
		wderror((struct buf *)NULL, du, "wdsetctlr failed");
		return (1);
	}
	return (0);
}

/*
 * Wait until driver is inactive, then set up controller.
 */
static int
wdwsetctlr(struct disk *du)
{
	int	stat;
	int	x;

	wdsleep(du->dk_ctrlr, "wdwset");
	x = splbio();
	stat = wdsetctlr(du);
	wdflushirq(du, x);
	splx(x);
	return (stat);
}

/*
 * issue READP to drive to ask it what it is.
 */
static int
wdgetctlr(struct disk *du)
{
	int	i;
	char	tb[DEV_BSIZE];
	struct wdparams *wp;

	if (wdcommand(du, 0, 0, 0, 0, WDCC_READP) != 0
	    || wdwait(du, WDCS_READY | WDCS_SEEKCMPLT | WDCS_DRQ, TIMEOUT) != 0) {
		/* XXX need to check error status after final transfer. */
		/*
		 * Old drives don't support WDCC_READP.  Try a seek to 0.
		 * Some IDE controllers return trash if there is no drive
		 * attached, so first test that the drive can be selected.
		 * This also avoids long waits for nonexistent drives.
		 */
		if (wdwait(du, 0, TIMEOUT) < 0)
			return (1);
		outb(du->dk_port + wd_sdh, WDSD_IBM | (du->dk_unit << 4));
		DELAY(5000);	/* usually unnecessary; drive select is fast */
		if ((inb(du->dk_port + wd_status) & (WDCS_BUSY | WDCS_READY))
		    != WDCS_READY
		    || wdcommand(du, 0, 0, 0, 0, WDCC_RESTORE | WD_STEP) != 0
		    || wdwait(du, WDCS_READY | WDCS_SEEKCMPLT, TIMEOUT) != 0)
			return (1);

		/*
		 * Fake minimal drive geometry for reading the MBR.
		 * readdisklabel() may enlarge it to read the label and the
		 * bad sector table.
		 */
		du->dk_dd.d_secsize = DEV_BSIZE;
		du->dk_dd.d_nsectors = 17;
		du->dk_dd.d_ntracks = 1;
		du->dk_dd.d_ncylinders = 1;
		du->dk_dd.d_secpercyl = 17;
		du->dk_dd.d_secperunit = 17;

		/*
		 * Fake maximal drive size for writing the label.
		 */
		du->dk_dd.d_partitions[WDRAW].p_size = 64 * 16 * 1024;

		/*
		 * Fake some more of the label for printing by disklabel(1)
		 * in case there is no real label.
		 */
		du->dk_dd.d_type = DTYPE_ST506;
		du->dk_dd.d_subtype |= DSTYPE_GEOMETRY;
		strncpy(du->dk_dd.d_typename, "Fake geometry",
			sizeof du->dk_dd.d_typename);

		/* Fake the model name for printing by wdattach(). */
		strncpy(du->dk_params.wdp_model, "unknown",
			sizeof du->dk_params.wdp_model);

		return (0);
	}

	/* obtain parameters */
	wp = &du->dk_params;
	insw(du->dk_port + wd_data, tb, sizeof(tb) / sizeof(short));
	bcopy(tb, wp, sizeof(struct wdparams));

	/* shuffle string byte order */
	for (i = 0; i < sizeof(wp->wdp_model); i += 2) {
		u_short *p;

		p = (u_short *) (wp->wdp_model + i);
		*p = ntohs(*p);
	}
	/*
	 * Clean up the wdp_model by converting nulls to spaces, and
	 * then removing the trailing spaces.
	 */
	for (i=0; i < sizeof(wp->wdp_model); i++) {
		if (wp->wdp_model[i] == '\0') {
			wp->wdp_model[i] = ' ';
		}
	}
	for (i=sizeof(wp->wdp_model)-1; i>=0 && wp->wdp_model[i]==' '; i--) {
		wp->wdp_model[i] = '\0';
	}

#ifdef WDDEBUG
	printf(
"\nwd(%d,%d): wdgetctlr: gc %x cyl %d trk %d sec %d type %d sz %d model %s\n",
	       du->dk_ctrlr, du->dk_unit, wp->wdp_config,
	       wp->wdp_fixedcyl + wp->wdp_removcyl, wp->wdp_heads,
	       wp->wdp_sectors, wp->wdp_cntype, wp->wdp_cnsbsz,
	       wp->wdp_model);
#endif

	/* update disklabel given drive information */
	du->dk_dd.d_secsize = DEV_BSIZE;
	du->dk_dd.d_ncylinders = wp->wdp_fixedcyl + wp->wdp_removcyl /*+- 1*/ ;
	du->dk_dd.d_ntracks = wp->wdp_heads;
	du->dk_dd.d_nsectors = wp->wdp_sectors;
	du->dk_dd.d_secpercyl = du->dk_dd.d_ntracks * du->dk_dd.d_nsectors;
	du->dk_dd.d_partitions[WDRAW].p_size = du->dk_dd.d_secperunit
	    = du->dk_dd.d_secpercyl * du->dk_dd.d_ncylinders;
	/* dubious ... */
	bcopy("ESDI/IDE", du->dk_dd.d_typename, 9);
	bcopy(wp->wdp_model + 20, du->dk_dd.d_packname, 14 - 1);
	/* better ... */
	du->dk_dd.d_type = DTYPE_ESDI;
	du->dk_dd.d_subtype |= DSTYPE_GEOMETRY;

	return (0);
}


/* ARGSUSED */
int
wdclose(dev_t dev, int flags, int fmt)
{
	register struct disk *du;
	int	part = wdpart(dev), mask = 1 << part;

	if (wddospart(dev))
		return (0);

	du = wddrives[wdunit(dev)];

	switch (fmt) {
	case S_IFCHR:
		du->dk_copenpart &= ~mask;
		break;
	case S_IFBLK:
		du->dk_bopenpart &= ~mask;
		break;
	}
	du->dk_openpart = du->dk_copenpart | du->dk_bopenpart;

	return (0);
}

int
wdioctl(dev_t dev, int cmd, caddr_t addr, int flag)
{
	int	lunit = wdunit(dev);
	register struct disk *du;
	int	error = 0;
#ifdef notyet
	struct uio auio;
	struct iovec aiov;
#endif

	du = wddrives[lunit];

	switch (cmd) {

	case DIOCSBAD:
		if ((flag & FWRITE) == 0)
			error = EBADF;
		else
			du->dk_bad = *(struct dkbad *)addr;
		break;

	case DIOCGDINFO:
		*(struct disklabel *)addr = du->dk_dd;
		break;

	case DIOCGPART:
		if (wddospart(dev))
			return (EINVAL);
		((struct partinfo *)addr)->disklab = &du->dk_dd;
		((struct partinfo *)addr)->part =
		    &du->dk_dd.d_partitions[wdpart(dev)];
		break;

	case DIOCSDINFO:
		if ((flag & FWRITE) == 0)
			error = EBADF;
		else
			error = setdisklabel(&du->dk_dd,
					     (struct disklabel *)addr,
#if 0
					    /*
					     * XXX setdisklabel() uses the
					     * openmask to allow it to reject
					     * changing open partitions.  Why
					     * are we pretending nothing is
					     * open?
					     */
					     du->dk_flags & DKFL_BSDLABEL
					     ? du->dk_openpart :
#endif
					     0,
					     du->dk_dospartitions);
		if (error == 0) {
			du->dk_flags |= DKFL_BSDLABEL;
			wdwsetctlr(du);	/* XXX - check */
		}
		break;

	case DIOCWLABEL:
		du->dk_flags &= ~DKFL_WRITEPROT;
		if ((flag & FWRITE) == 0)
			error = EBADF;
		else
			du->dk_wlabel = *(int *)addr;
		break;

	case DIOCWDINFO:
		du->dk_flags &= ~DKFL_WRITEPROT;
		if ((flag & FWRITE) == 0)
			error = EBADF;
		else if ((error = setdisklabel(&du->dk_dd,
					       (struct disklabel *)addr,
#if 0
					       du->dk_flags & DKFL_BSDLABEL
					       ? du->dk_openpart :
#endif
					       0,
					       du->dk_dospartitions)) == 0) {
			int	wlab;

			du->dk_flags |= DKFL_BSDLABEL;
			wdwsetctlr(du);	/* XXX - check */

			/* simulate opening partition 0 so write succeeds */
			du->dk_openpart |= (1 << 0);	/* XXX */
			wlab = du->dk_wlabel;
			du->dk_wlabel = 1;
			error = writedisklabel(dev, (d_strategy_t *) WDSTRATEGY,
					&du->dk_dd, du->dk_dospartitions);
			du->dk_openpart = du->dk_copenpart | du->dk_bopenpart;
			du->dk_wlabel = wlab;
		}
		break;

#ifdef notyet
	case DIOCGDINFOP:
		*(struct disklabel **)addr = &(du->dk_dd);
		break;

	case DIOCWFORMAT:
		if ((flag & FWRITE) == 0)
			error = EBADF;
		else {
			register struct format_op *fop;

			fop = (struct format_op *)addr;
			aiov.iov_base = fop->df_buf;
			aiov.iov_len = fop->df_count;
			auio.uio_iov = &aiov;
			auio.uio_iovcnt = 1;
			auio.uio_resid = fop->df_count;
			auio.uio_segflg = 0;
			auio.uio_offset =
			    fop->df_startblk * du->dk_dd.d_secsize;
#error /* XXX the 386BSD interface is different */
			error = physio(wdformat, &rwdbuf[lunit], 0, dev,
				       B_WRITE, minphys, &auio);
			fop->df_count -= auio.uio_resid;
			fop->df_reg[0] = du->dk_status;
			fop->df_reg[1] = du->dk_error;
		}
		break;
#endif

	default:
		error = ENOTTY;
		break;
	}
	return (error);
}

#ifdef B_FORMAT
int
wdformat(struct buf *bp)
{

	bp->b_flags |= B_FORMAT;
	return (wdstrategy(bp));
}
#endif

int
wdsize(dev_t dev)
{
	int	lunit = wdunit(dev), part = wdpart(dev), val;
	struct disk *du;

	if (lunit >= NWD || wddospart(dev) || (du = wddrives[lunit]) == NULL)
		return (-1);
	val = 0;
	if (du->dk_state == CLOSED)
		val = wdopen(makewddev(major(dev), lunit, WDRAW),
			     FREAD, S_IFBLK, 0);
	if (val != 0 || du->dk_flags & DKFL_WRITEPROT)
		return (-1);
	return ((int)du->dk_dd.d_partitions[part].p_size);
}

extern char *vmmap;		/* poor name! */

/*
 * Dump core after a system crash.
 */
int
wddump(dev_t dev)
{
	register struct disk *du;
	register struct bt_bad *bt_ptr;
	struct disklabel *lp;
	long	num;		/* number of sectors to write */
	int	lunit, part;
	long	blkoff, blknum;
	long	blkchk, blkcnt, blknext;
	long	cylin, head, sector;
	long	secpertrk, secpercyl, nblocks;
	char   *addr;
	extern int Maxmem;
	static int wddoingadump = 0;
	extern caddr_t CADDR1;

	/* Toss any characters present prior to dump. */
	while (sgetc(1))
		;

	/* Check for acceptable device. */
	/* XXX should reset to maybe allow du->dk_state < OPEN. */
	lunit = wdunit(dev);	/* eventually support floppies? */
	part = wdpart(dev);
	if (lunit >= NWD || wddospart(dev) || (du = wddrives[lunit]) == NULL
	    || du->dk_state < OPEN || du->dk_flags & DKFL_WRITEPROT)
		return (ENXIO);

	/* Size of memory to dump, in disk sectors. */
	num = (u_long)Maxmem * NBPG / du->dk_dd.d_secsize;

	secpertrk = du->dk_dd.d_nsectors;
	secpercyl = du->dk_dd.d_secpercyl;
	nblocks = du->dk_dd.d_partitions[part].p_size;
	blkoff = du->dk_dd.d_partitions[part].p_offset;

#if 0
	pg("part %x, nblocks %d, dumplo %d num %d\n",
	   part, nblocks, dumplo, num);
#endif

	/* Check transfer bounds against partition size. */
	if (dumplo < 0 || dumplo + num > nblocks)
		return (EINVAL);

	/* Check if we are being called recursively. */
	if (wddoingadump)
		return (EFAULT);

#if 0
	/* Mark controller active for if we panic during the dump. */
	wdtab[du->dk_ctrlr].b_active = 1;
#endif
	wddoingadump = 1;

	/* Recalibrate the drive. */
	DELAY(5);		/* ATA spec XXX NOT */
	if (wdcommand(du, 0, 0, 0, 0, WDCC_RESTORE | WD_STEP) != 0
	    || wdwait(du, WDCS_READY | WDCS_SEEKCMPLT, TIMEOUT) != 0
	    || wdsetctlr(du) != 0) {
		wderror((struct buf *)NULL, du, "wddump: recalibrate failed");
		return (EIO);
	}

	du->dk_flags |= DKFL_SINGLE;
	addr = (char *) 0;
	blknum = dumplo + blkoff;
	while (num > 0) {
		blkcnt = num;
		if (blkcnt > MAXTRANSFER)
			blkcnt = MAXTRANSFER;
		/* Keep transfer within current cylinder. */
		if ((blknum + blkcnt - 1) / secpercyl != blknum / secpercyl)
			blkcnt = secpercyl - (blknum % secpercyl);
		blknext = blknum + blkcnt;

		/* 
		 * See if one of the sectors is in the bad sector list
		 * (if we have one).  If the first sector is bad, then
		 * reduce the transfer to this one bad sector; if another
		 * sector is bad, then reduce reduce the transfer to
		 * avoid any bad sectors.
		 */
		if ((du->dk_flags & (DKFL_SINGLE | DKFL_BADSECT))
		    == (DKFL_SINGLE | DKFL_BADSECT))
		  for (blkchk = blknum; blkchk < blknum + blkcnt; blkchk++) {
		    cylin = blkchk / secpercyl;
		    head = (blkchk % secpercyl) / secpertrk;
		    sector = blkchk % secpertrk;
		    for (bt_ptr = du->dk_bad.bt_bad;
			 bt_ptr->bt_cyl != BAD144_NO_CYL; bt_ptr++) {
			if (bt_ptr->bt_cyl > cylin)
				/*
				 * Sorted list, and we passed our cylinder.
				 * quit.
				 */
				break;
			if (bt_ptr->bt_cyl == cylin &&
			    bt_ptr->bt_trksec == (head << 8) + sector) {
				/* Found bad block. */
				blkcnt = blkchk - blknum;
				if (blkcnt > 0) {
					blknext = blknum + blkcnt;
					goto out;
				}
				blkcnt = 1;
				blknext = blknum + blkcnt;
			/*
			 * Found bad block.  Calculate new block number.
			 * This starts at the end of the disk (skip the
			 * last track which is used for the bad block list),
			 * and works backwards to the front of the disk.
			 */
				/* XXX as usual. */
#ifdef WDDEBUG
				printf("--- badblock code -> Old = %ld; ",
				       blknum);
#endif
				lp = &du->dk_dd;
				if (lp->d_partitions[BSD_PART].p_offset != 0)
					blknum = lp->d_partitions[BAD144_PART]
						     .p_offset
						 + lp->d_partitions[BAD144_PART]
						       .p_size;
				else
					blknum = lp->d_secperunit;
				blknum -= lp->d_nsectors
					  + (bt_ptr - du->dk_bad.bt_bad) + 1;
#ifdef WDDEBUG
				printf("new = %ld\n", blknum);
#endif
				break;
			}
		    }
		  }
out:

		/* Compute disk address. */
		cylin = blknum / secpercyl;
		head = (blknum % secpercyl) / secpertrk;
		sector = blknum % secpertrk;

#if 0
		/* Let's just talk about this first... */
		pg("cylin l%d head %ld sector %ld addr 0x%x count %ld",
		   cylin, head, sector, addr, blkcnt);
#endif

		/* Do the write. */
		if (wdcommand(du, cylin, head, sector, blkcnt, WDCC_WRITE)
		    != 0) {
			wderror((struct buf *)NULL, du,
				"wddump: timeout waiting to to give command");
			return (EIO);
		}
		while (blkcnt != 0) {
			pmap_enter(kernel_pmap, CADDR1, trunc_page(addr),
				   VM_PROT_READ, TRUE);

			/* Ready to send data? */
			DELAY(5);	/* ATA spec */
			if (wdwait(du, WDCS_READY | WDCS_SEEKCMPLT | WDCS_DRQ, TIMEOUT)
			    < 0) {
				wderror((struct buf *)NULL, du,
					"wddump: timeout waiting for DRQ");
				return (EIO);
			}
			outsw(du->dk_port + wd_data,
			      CADDR1 + ((int)addr & (NBPG - 1)),
			      DEV_BSIZE / sizeof(short));
			addr += DEV_BSIZE;
			if ((unsigned)addr % (1024 * 1024) == 0)
				printf("%ld ", num / (1024 * 1024 / DEV_BSIZE));
			num--;
			blkcnt--;
		}

		/* Wait for completion. */
		DELAY(5);	/* ATA spec XXX NOT */
		if (wdwait(du, WDCS_READY | WDCS_SEEKCMPLT, TIMEOUT) < 0) {
			wderror((struct buf *)NULL, du,
				"wddump: timeout waiting for status");
			return (EIO);
		}

		/* Check final status. */
		if (du->dk_status
		    & (WDCS_READY | WDCS_SEEKCMPLT | WDCS_DRQ | WDCS_ERR)
		    != (WDCS_READY | WDCS_SEEKCMPLT)) {
			wderror((struct buf *)NULL, du,
				"wddump: extra DRQ, or error");
			return (EIO);
		}

		/* Update block count. */
		blknum = blknext;

		/* Operator aborting dump? */
		if (sgetc(1) & 0xff)	/* EWS: A hack to work with syscons */
			return (EINTR);
	}
	return (0);
}

static void
wderror(struct buf *bp, struct disk *du, char *mesg)
{
	if (bp == NULL)
		printf("wd%d: %s:\n", du->dk_lunit, mesg);
	else
		diskerr(bp, "wd", mesg, LOG_PRINTF, du->dk_skip, &du->dk_dd);
	printf("wd%d: status %b error %b\n", du->dk_lunit,
	       du->dk_status, WDCS_BITS, du->dk_error, WDERR_BITS);
}

/*
 * Discard any interrupts that were latched by the interrupt system while
 * we were doing polled i/o.
 */
static void
wdflushirq(struct disk *du, int old_ipl)
{
	wdtab[du->dk_ctrlr].b_active = 2;
	splx(old_ipl);
	(void)splbio();
	wdtab[du->dk_ctrlr].b_active = 0;
}

/*
 * Reset the controller.
 */
static int
wdreset(struct disk *du)
{
	int	wdc;

	wdc = du->dk_port;
	(void)wdwait(du, 0, TIMEOUT);
	outb(wdc + wd_ctlr, WDCTL_IDS | WDCTL_RST);
	DELAY(10 * 1000);
	outb(wdc + wd_ctlr, WDCTL_IDS);
	if (wdwait(du, WDCS_READY | WDCS_SEEKCMPLT, TIMEOUT) != 0
	    || (du->dk_error = inb(wdc + wd_error)) != 0x01)
		return (1);
	outb(wdc + wd_ctlr, WDCTL_4BIT);
	return (0);
}

/*
 * Sleep until driver is inactive.
 * This is used only for avoiding rare race conditions, so it is unimportant
 * that the sleep may be far too short or too long.
 */
static void
wdsleep(int ctrlr, char *wmesg)
{
	while (wdtab[ctrlr].b_active)
		tsleep((caddr_t)&wdtab[ctrlr].b_active, PZERO - 1, wmesg, 1);
}

static void
wdtimeout(caddr_t cdu, int ticks)
{
	struct disk *du;
	int	x;

	du = (struct disk *)cdu;
	x = splbio();
	if (du->dk_timeout != 0 && --du->dk_timeout == 0) {
		wderror((struct buf *)NULL, du, "interrupt timeout");
		wdunwedge(du);
		wdflushirq(du, x);
		du->dk_skip = 0;
		du->dk_flags |= DKFL_SINGLE;
		wdstart(du->dk_ctrlr);
	}
	timeout(wdtimeout, cdu, hz);
	splx(x);
}

/*
 * Reset the controller after it has become wedged.  This is different from
 * wdreset() so that wdreset() can be used in the probe and so that this
 * can restore the geometry .
 */
static int
wdunwedge(struct disk *du)
{
	struct disk *du1;
	int	lunit;

	/* Schedule other drives for recalibration. */
	for (lunit = 0; lunit < NWD; lunit++)
		if ((du1 = wddrives[lunit]) != NULL && du1 != du
		    && du1->dk_ctrlr == du->dk_ctrlr
		    && du1->dk_state > WANTOPEN)
			du1->dk_state = WANTOPEN;

	DELAY(RECOVERYTIME);
	if (wdreset(du) == 0) {
		/*
		 * XXX - recalibrate current drive now because some callers
		 * aren't prepared to have its state change.
		 */
		if (wdcommand(du, 0, 0, 0, 0, WDCC_RESTORE | WD_STEP) == 0
		    && wdwait(du, WDCS_READY | WDCS_SEEKCMPLT, TIMEOUT) == 0
		    && wdsetctlr(du) == 0)
			return (0);
	}
	wderror((struct buf *)NULL, du, "wdunwedge failed");
	return (1);
}

/*
 * Wait uninterruptibly until controller is not busy and either certain
 * status bits are set or an error has occurred.
 * The wait is usually short unless it is for the controller to process
 * an entire critical command.
 * Return 1 for (possibly stale) controller errors, -1 for timeout errors,
 * or 0 for no errors.
 * Return controller status in du->dk_status and, if there was a controller
 * error, return the error code in du->dk_error.
 */
#ifdef WD_COUNT_RETRIES
static int min_retries[NWDC];
#endif

static int
wdwait(struct disk *du, u_char bits_wanted, int timeout)
{
	int	wdc;
	u_char	status;

#define	POLLING		1000

	wdc = du->dk_port;
	timeout += POLLING;
	do {
#ifdef WD_COUNT_RETRIES
		if (min_retries[du->dk_ctrlr] > timeout
		    || min_retries[du->dk_ctrlr] == 0)
			min_retries[du->dk_ctrlr] = timeout;
#endif
		DELAY(5);	/* ATA spec XXX NOT */
		du->dk_status = status = inb(wdc + wd_status);
		if (!(status & WDCS_BUSY)) {
			if (status & WDCS_ERR) {
				du->dk_error = inb(wdc + wd_error);
				/*
				 * We once returned here.  This is wrong
				 * because the error bit is apparently only
				 * valid after the controller has interrupted
				 * (e.g., the error bit is stale when we wait
				 * for DRQ for writes).  So we can't depend
				 * on the error bit at all when polling for
				 * command completion.
				 */
			}
			if ((status & bits_wanted) == bits_wanted)
				return (status & WDCS_ERR);
		}
		if (timeout < TIMEOUT)
			/*
			 * Switch to a polling rate of about 1 KHz so that
			 * the timeout is almost machine-independent.  The
			 * controller is taking a long time to respond, so
			 * an extra msec won't matter.
			 */
			DELAY(1000);
	} while (--timeout != 0);
	return (-1);
}

#endif /* NWDC > 0 */