NetBSD/sys/scsi/sd.c

/*
 * Written by Julian Elischer (julian@tfs.com)
 * for TRW Financial Systems for use under the MACH(2.5) operating system.
 * Hacked by Theo de Raadt <deraadt@fsa.ca>
 *
 * TRW Financial Systems, in accordance with their agreement with Carnegie
 * Mellon University, makes this software available to CMU to distribute
 * or use in any manner that they see fit as long as this message is kept with
 * the software. For this reason TFS also grants any other persons or
 * organisations permission to use or modify this software.
 *
 * TFS supplies this software to be publicly redistributed
 * on the understanding that TFS is not responsible for the correct
 * functioning of this software in any circumstances.
 *
 *	$Id: sd.c,v 1.19 1993/12/17 08:50:56 mycroft Exp $
 */

#include "sd.h"

#include <sys/types.h>
#include <sys/param.h>
#include <sys/dkbad.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/buf.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/errno.h>
#include <sys/disklabel.h>

#include <scsi/scsi_all.h>
#include <scsi/scsi_disk.h>
#include <scsi/scsiconf.h>
#include <scsi/sddefs.h>

long int sdstrats, sdqueues;

#define SPLSD splbio
#define ESUCCESS 0

#define SECSIZE		512
#define PDLOCATION	29	
#define BOOTRECORDSIGNATURE			(0x55aa & 0x00ff)
#define	SDOUTSTANDING	2
#define SDQSIZE		4
#define	SD_RETRIES	4

#define MAKESDDEV(maj, unit, part)	(makedev(maj, ((unit<<3)+part)))
#define	UNITSHIFT	3
#define PARTITION(z)	(minor(z) & 0x07)
#define	RAW_PART	3
#define UNIT(z)		(  (minor(z) >> UNITSHIFT) )

#undef	NSD
#define NSD		( makedev(1,0) >> UNITSHIFT)

#define WHOLE_DISK(unit) ( (unit << UNITSHIFT) + RAW_PART )

struct sd_data *sd_data[NSD];
int sd_debug = 0;

/*
 * The routine called by the low level scsi routine when it discovers
 * A device suitable for this driver
 */
int
sdattach(int masunit, struct scsi_switch *sw, int physid, int *unit)
{
	struct scsi_xfer *sd_scsi_xfer;
	struct disk_parms *dp;
	struct sd_data *sd;
	unsigned char *tbl;
	long int ad_info;
	int targ, lun, i;

	targ = physid >> 3;
	lun = physid & 7;

	/*printf("sdattach: sd%d at %s%d target %d lun %d\n",
		*unit, sw->name, masunit, targ, lun);*/

	if(*unit == -1) {
		for(i=0; i<NSD && *unit==-1; i++)
			if(sd_data[i]==NULL)
				*unit = i;
	}
	if(*unit > NSD || *unit==-1)
		return 0;
	if(sd_data[*unit])
		return 0;

	sd = sd_data[*unit] = (struct sd_data *)malloc(sizeof *sd,
		M_TEMP, M_NOWAIT);
	if(!sd)
		return 0;
	bzero(sd, sizeof *sd);

	/* store information needed to contact our base driver */
	sd->sc_sw = sw;
	sd->ctlr = masunit;
	sd->targ = targ;
	sd->lu = lun;

	dp = &(sd->params);
	if(scsi_debug & PRINTROUTINES)
		printf("sdattach: "); 

	if(sd->sc_sw->adapter_info) {
		sd->ad_info = ( (*(sd->sc_sw->adapter_info))(masunit));
		sd->cmdscount =	sd->ad_info & AD_INF_MAX_CMDS;
		if(sd->cmdscount > SDOUTSTANDING)
			sd->cmdscount = SDOUTSTANDING;
	} else {
		sd->ad_info = 1;
		sd->cmdscount =	1;
	}

	i = sd->cmdscount;
	sd_scsi_xfer = (struct scsi_xfer *)malloc(sizeof(struct scsi_xfer) * i,
		M_TEMP, M_NOWAIT);
	while(i--) {
		sd_scsi_xfer->next = sd->freexfer;
		sd->freexfer = sd_scsi_xfer;
		sd_scsi_xfer++;
	}

	/*
	 * Use the subdriver to request information regarding
	 * the drive. We cannot use interrupts yet, so the
	 * request must specify this.
	 */
	sd_get_parms(*unit,  SCSI_NOSLEEP |  SCSI_NOMASK);
	printf("sd%d at %s%d targ %d lun %d: %dMB %d cyl, %d head, %d sec, %d byte/sec\n",
		*unit, sw->name, masunit, targ, lun,
		(dp->cyls*dp->heads*dp->sectors*dp->secsiz)/ (1024*1024),
		dp->cyls, dp->heads, dp->sectors, dp->secsiz);

	sd->flags |= SDINIT;
	return 1;
}


/*
 * open the device. Make sure the partition info
 * is a up-to-date as can be.
 */
int
sdopen(int dev)
{
	struct disk_parms disk_parms;
	struct sd_data *sd;
	int errcode = 0;
	int unit, part;

	unit = UNIT(dev);
	part = PARTITION(dev);
	if(scsi_debug & (PRINTROUTINES | TRACEOPENS))
		printf("sdopen: dev=0x%x (unit %d (of %d),partition %d)\n",
			dev, unit, NSD, part);

	if(unit > NSD)
		return ENXIO;
	if( !sd_data[unit]) {
		if(scsi_debug & PRINTROUTINES)
			printf("nonexistant!\n");
		return ENXIO;
	}

	sd = sd_data[unit];
	if(!sd)
		return ENXIO;
	if( !(sd->flags & SDVALID) )
		return ENXIO;

	/*
	 * Make sure the disk has been initialised.
	 * XXX get the scsi driver to look for a new device if
	 * we are not initted, like SunOS
	 */
	if( !(sd->flags & SDINIT))
		return ENXIO;

	/*
	 * If it's been invalidated, and not everybody has
	 * closed it then forbid re-entry.
	 */
	if( !(sd->flags & SDVALID) && sd->openparts)
		return ENXIO;

	/*
	 * Check that it is still responding and ok.
	 * "unit attention errors should occur here if the drive
	 * has been restarted or the pack changed
	 */
	if(scsi_debug & TRACEOPENS)
		printf("device is ");

	/*
	 * In case it is a funny one, tell it to start
	 * not needed for most hard drives (ignore failure)
	 *
	 * This needs to be done BEFORE the test_unit_ready - davidb/simonb
	 */
	sd_start_unit(unit, SCSI_ERR_OK|SCSI_SILENT);
	if(scsi_debug & TRACEOPENS)
		printf("started ");

	if (sd_test_unit_ready(unit, 0)) {
		if(scsi_debug & TRACEOPENS)
			printf("not responding\n");
		return ENXIO;
	}
	if(scsi_debug & TRACEOPENS)
		printf("ok\n");

	/*
	 * Load the physical device parameters 
	 */
	sd_get_parms(unit, 0);			/* sets SDVALID */
	if( sd->params.secsiz != SECSIZE) {
		printf("sd%d: Can't deal with %d bytes logical blocks\n",
			unit, sd->params.secsiz);
		return ENXIO;
	}
	if(scsi_debug & TRACEOPENS)
		printf("Params loaded ");

	/*
	 * Load the partition info if not already loaded
	 */
	sd_prevent(unit, PR_PREVENT, SCSI_ERR_OK|SCSI_SILENT);
	if( (errcode=sdgetdisklabel(unit)) && (part != RAW_PART)) {
		sd_prevent(unit, PR_ALLOW, SCSI_ERR_OK|SCSI_SILENT);
		return errcode;
	}
	if(scsi_debug & TRACEOPENS)
		printf("Disklabel loaded ");

	/*
	 * Check the partition is legal
	 */
	if ( part >= MAXPARTITIONS ) {
		sd_prevent(unit, PR_ALLOW, SCSI_ERR_OK|SCSI_SILENT);
		return ENXIO;
	}
	if(scsi_debug & TRACEOPENS)
		printf("ok");

	/*
	 *  Check that the partition exists
	 */
	if( sd->disklabel.d_partitions[part].p_size==0 && part!=RAW_PART) {
		sd_prevent(unit, PR_ALLOW, SCSI_ERR_OK|SCSI_SILENT);
		return ENXIO;
	}

	sd->partflags[part] |= SDOPEN;
	sd->openparts |= (1 << part);
	if(scsi_debug & TRACEOPENS)
		printf("open %d %d\n", sdstrats, sdqueues);
	return 0;
}

/*
 * Get ownership of a scsi_xfer
 * If need be, sleep on it, until it comes free
 */
struct scsi_xfer *
sd_get_xs(int unit, int flags)
{
	struct sd_data *sd = sd_data[unit];
	struct scsi_xfer *xs;
	int s;

	if(flags & (SCSI_NOSLEEP |  SCSI_NOMASK)) {
		if (xs = sd->freexfer) {
			sd->freexfer = xs->next;
			xs->flags = 0;
		}
	} else {
		s = SPLSD();
		while (!(xs = sd->freexfer)) {
			sd->blockwait++;  /* someone waiting! */
			tsleep((caddr_t)&sd->freexfer, PRIBIO+1, "sd_get_xs",0);
			sd->blockwait--;
		}
		sd->freexfer = xs->next;
		splx(s);
		xs->flags = 0;
	}
	return xs;
}

/*
 * Free a scsi_xfer, wake processes waiting for it
 */
void
sd_free_xs(int unit, struct scsi_xfer *xs, int flags)
{
	struct sd_data *sd = sd_data[unit];
	int s;
	
	if(flags & SCSI_NOMASK) {
		if (sd->blockwait) {
			printf("doing a wakeup from NOMASK mode\n");
			wakeup((caddr_t)&sd->freexfer);
		}
		xs->next = sd->freexfer;
		sd->freexfer = xs;
	} else {
		s = SPLSD();
		if (sd->blockwait)
			wakeup((caddr_t)&sd->freexfer);
		xs->next = sd->freexfer;
		sd->freexfer = xs;
		splx(s);
	}
}

/*
 * trim the size of the transfer if needed, called by physio
 * basically the smaller of our max and the scsi driver's
 * minphys (note we have no max)
 */
void
sdminphys(struct buf *bp)
{
	(*(sd_data[UNIT(bp->b_dev)]->sc_sw->scsi_minphys))(bp);
}

/*
 * Actually translate the requested transfer into
 * one the physical driver can understand
 * The transfer is described by a buf and will include
 * only one physical transfer.
 */
int
sdstrategy(struct buf *bp)
{
	struct sd_data *sd;
	unsigned int opri;
	struct	buf *dp;
	int unit;

	sdstrats++;
	unit = UNIT((bp->b_dev));

	if(unit > NSD) {
		printf("sdstrategy bailout: %d %d\n", unit, NSD);
		bp->b_error = EIO;
		goto bad;
	}
	if( !sd_data[unit]) {
		printf("sdstrategy bailout\n");
		bp->b_error = EIO;
		goto bad;
	}		

	sd = sd_data[unit];
	if(scsi_debug & PRINTROUTINES)
		printf("\nsdstrategy ");
	if(scsi_debug & SHOWREQUESTS)
		printf("sd%d: %d bytes @ blk%d\n",
			unit, bp->b_bcount, bp->b_blkno);

	/* Reject non block-aligned transfers */
	if (bp->b_bcount % SECSIZE) {
		bp->b_error = EINVAL;
		goto bad;
	}

	sdminphys(bp);

	/* If the device has been made invalid, error out */
	if(!(sd->flags & SDVALID)) {
		bp->b_error = EIO;
		goto bad;
	}

	/* "soft" write protect check */
	if ((sd->flags & SDWRITEPROT) && (bp->b_flags & B_READ) == 0) {
		bp->b_error = EROFS;
		goto bad;
	}

	/* If it's a null transfer, return immediately */
	if (bp->b_bcount == 0)
		goto done;

	/*
	 * Decide which unit and partition we are talking about
	 * only raw is ok if no label
	 */
	if(PARTITION(bp->b_dev) != RAW_PART) {
		if (!(sd->flags & SDHAVELABEL)) {
			bp->b_error = EIO;
			goto bad;
		}

		/*
		 * do bounds checking, adjust transfer. if error, process.
		 * if end of partition, just return
		 */
		if (bounds_check_with_label(bp, &sd->disklabel, sd->wlabel) <= 0)
			goto done;
		/* otherwise, process transfer request */
	}

	opri = SPLSD();
	dp = &(sd_data[unit]->sdbuf);

	/* Place it in the queue of disk activities for this disk */
	disksort(dp, bp);

	/*
	 * Tell the device to get going on the transfer if it's
	 * not doing anything, otherwise just wait for completion
	 */
	sdstart(unit);

	splx(opri);
	return;
bad:
	bp->b_flags |= B_ERROR;
done:
	/* Correctly set the buf to indicate a completed xfer */
  	bp->b_resid = bp->b_bcount;
	biodone(bp);
	return;
}

/*
 * sdstart looks to see if there is a buf waiting for the device
 * and that the device is not already busy. If both are true,
 * It deques the buf and creates a scsi command to perform the
 * transfer in the buf. The transfer request will call sd_done
 * on completion, which will in turn call this routine again
 * so that the next queued transfer is performed.
 * The bufs are queued by the strategy routine (sdstrategy)
 * This routine is also called after other non-queued requests
 * have been made of the scsi driver, to ensure that the queue
 * continues to be drained.
 * must be called at the correct (highish) spl level
 * sdstart() is called at SPLSD from sdstrategy and sd_done
 */
void
sdstart(int unit)
{
	register struct buf *bp = 0, *dp;
	struct sd_data *sd = sd_data[unit];
	struct scsi_rw_big cmd;
	struct scsi_xfer *xs;
	struct partition *p;
	int drivecount, blkno, nblk;

	if(scsi_debug & PRINTROUTINES)
		printf("sdstart%d ", unit);

	sd = sd_data[unit];
	if(!sd)
		return;

	/*
	 * See if there is a buf to do and we are not already
	 * doing one
	 */
	if(!sd->freexfer)
		return;    /* none for us, unit already underway */

	if(sd->blockwait)    /* there is one, but a special waits */
		return;	/* give the special that's waiting a chance to run */


	dp = &(sd_data[unit]->sdbuf);
	if ((bp = dp->b_actf) != NULL)	/* yes, an assign */
		dp->b_actf = bp->av_forw;
	else
		return;

	xs=sd_get_xs(unit, 0);		/* ok we can grab it */
	xs->flags = INUSE;		/* Now ours */

	/*
	 *  If the device has become invalid, abort all the reads
	 * and writes until all files have been closed and re-openned
	 */
	if( !(sd->flags & SDVALID) ) {
		xs->error = XS_DRIVER_STUFFUP;
		sd_done(unit,xs);  /* clean up (calls sdstart) */
		return ;
	}

	/*
	 * We have a buf, now we should move the data into
	 * a scsi_xfer definition and try start it
	 *  First, translate the block to absolute
	 */
	p = sd->disklabel.d_partitions + PARTITION(bp->b_dev);
	blkno = bp->b_blkno + p->p_offset;
	nblk = (bp->b_bcount + 511) >> 9;

	/* Fill out the scsi command */
	bzero(&cmd, sizeof(cmd));
	cmd.op_code = (bp->b_flags & B_READ) ? READ_BIG : WRITE_BIG;
	cmd.addr_3 = (blkno & 0xff000000) >> 24;
	cmd.addr_2 = (blkno & 0xff0000) >> 16;
	cmd.addr_1 = (blkno & 0xff00) >> 8;
	cmd.addr_0 = blkno & 0xff;
	cmd.length2 = (nblk & 0xff00) >> 8;
	cmd.length1 = (nblk & 0xff);

	/*
	 * Fill out the scsi_xfer structure
	 * Note: we cannot sleep as we may be an interrupt
	 */
	xs->flags |= SCSI_NOSLEEP;
	xs->adapter = sd->ctlr;
	xs->targ = sd->targ;
	xs->lu = sd->lu;
	xs->retries = SD_RETRIES;
	xs->timeout = 10000;		/* 10000 millisecs for a disk !*/
	xs->cmd = (struct scsi_generic *)&cmd;
	xs->cmdlen = sizeof(cmd);
	xs->resid = bp->b_bcount;
	xs->when_done = sd_done;
	xs->done_arg = unit;
	xs->done_arg2 = (int)xs;
	xs->error = XS_NOERROR;
	xs->bp = bp;
	xs->data = (u_char *)bp->b_un.b_addr;
	xs->datalen = bp->b_bcount;

	/* Pass all this info to the scsi driver */
	if ( (*(sd->sc_sw->scsi_cmd))(xs) != SUCCESSFULLY_QUEUED) {
		printf("sd%d: oops not queued",unit);
		xs->error = XS_DRIVER_STUFFUP;
		sd_done(unit, xs);	/* clean up (calls sdstart) */
	}
	sdqueues++;
}

/*
 * This routine is called by the scsi interrupt when
 * the transfer is complete.
 */
int
sd_done(int unit, struct scsi_xfer *xs)
{
	struct buf *bp;
	int retval, retries = 0;

	if(scsi_debug & PRINTROUTINES)
		printf("sd_done%d ",unit);
	if( !(xs->flags & INUSE))
		panic("scsi_xfer not in use!");
	if(bp = xs->bp) {
		switch(xs->error) {
		case XS_NOERROR:
			bp->b_error = 0;
			bp->b_resid = 0;
			break;
		case XS_SENSE:
			retval = (sd_interpret_sense(unit,xs));
			if(retval) {
				bp->b_flags |= B_ERROR;
				bp->b_error = retval;
			}
			break;
		case XS_TIMEOUT:
			printf("sd%d timeout\n",unit);
		case XS_BUSY:	/* should retry -- how? */
			/*
			 * SHOULD put buf back at head of queue
			 * and decrement retry count in (*xs)
			 * HOWEVER, this should work as a kludge
			 */
			if(xs->retries--) {
				xs->error = XS_NOERROR;
				xs->flags &= ~ITSDONE;
				if( (*(sd_data[unit]->sc_sw->scsi_cmd))(xs)
				    == SUCCESSFULLY_QUEUED) {
					/* don't wake the job, ok? */
					return;
				}
				xs->flags |= ITSDONE;
			} /* fall through */

		case XS_DRIVER_STUFFUP:
			bp->b_flags |= B_ERROR;
			bp->b_error = EIO;
			break;
		default:
			printf("sd%d: unknown error category from scsi driver\n", unit);
		}
		biodone(bp);
		sd_free_xs(unit, xs, 0);
		sdstart(unit);		/* If there's anything waiting.. do it */
	} else
		wakeup((caddr_t)xs);
}

/*
 * Perform special action on behalf of the user
 * Knows about the internals of this device
 */
int
sdioctl(dev_t dev, int cmd, caddr_t addr, int flag)
{
	/* struct sd_cmd_buf *args;*/
	struct scsi_format_parms *fparms;
	struct cpu_disklabel osdep;
	extern struct proc *curproc;
	register struct sd_data *sd;
	unsigned char unit, part;
	unsigned int opri;
	int error = 0, x;

	/* Find the device that the user is talking about */
	unit = UNIT(dev);
	part = PARTITION(dev);
	if(scsi_debug & PRINTROUTINES)
		printf("sdioctl%d ",unit);

	/* If the device is not valid.. abandon ship */
	if(unit > NSD)
		return EIO;
	sd = sd_data[unit];
	if(sd==NULL)
		return EIO;

	if(!(sd->flags & SDVALID))
		return EIO;

	switch(cmd) {
	case DIOCWFORMAT:
		if( suser(curproc->p_ucred, &curproc->p_acflag))
			return EPERM;

		x = splbio();
		if(sd->formatting)
			return EBUSY;
		sd->formatting = 1;
		(void)splx(x);

		fparms = (struct scsi_format_parms *)malloc(sizeof *fparms,
			M_TEMP, M_NOWAIT);
		if(!fparms) {
			error = EAGAIN;
			goto unlock;
		}

		if(copyin(&addr, fparms, sizeof fparms)!=0) {
			free(fparms, M_TEMP);
			error = EFAULT;
			goto unlock;
		}
		error = sd_format(unit, fparms, 0, 0);
		if(!error && copyout(&addr, fparms, sizeof fparms) )
			error = EFAULT;
		free(fparms, M_TEMP);
unlock:
		x = splbio();
		sd->formatting = 0;
		(void)splx(x);

		break;
	case DIOCRFORMAT:
		error = EINVAL;
		break;
	case DIOCSBAD:
		error = EINVAL;
		break;
	case DIOCGDINFO:
		*(struct disklabel *)addr = sd->disklabel;
		break;
	case DIOCGPART:
		((struct partinfo *)addr)->disklab = &sd->disklabel;
		((struct partinfo *)addr)->part =
		    &sd->disklabel.d_partitions[PARTITION(dev)];
		break;
	case DIOCSDINFO:
		if ((flag & FWRITE) == 0)
			error = EBADF;
		else {
			error = setdisklabel(&sd->disklabel, (struct disklabel *)addr,
			    /*(sd->flags & DKFL_BSDLABEL) ? sd->openparts : */0,
			    &sd->cpudisklabel);
		}
		if (error == 0)
			sd->flags |= SDHAVELABEL;
		break;
	case DIOCWLABEL:
		sd->flags &= ~SDWRITEPROT;
		if ((flag & FWRITE) == 0)
			error = EBADF;
		else
			sd->wlabel = *(int *)addr;
		break;
	case DIOCWDINFO:
		sd->flags &= ~SDWRITEPROT;
		if ((flag & FWRITE) == 0)
			error = EBADF;
		else {
			if ((error = setdisklabel(&sd->disklabel,
			    (struct disklabel *)addr,
			    /*(sd->flags & SDHAVELABEL) ? sd->openparts :*/0,
			    &sd->cpudisklabel)) == 0) {
				int wlab;

				sd->flags |= SDHAVELABEL; /* ok write will succeed */

				/* simulate opening partition 0 so write succeeds */
				sd->openparts |= (1 << 0);	    /* XXX */
				wlab = sd->wlabel;
				sd->wlabel = 1;
				error = writedisklabel(dev, sdstrategy,
					&sd->disklabel, &sd->cpudisklabel);
				sd->wlabel = wlab;
			}
		}
		break;
	default:
		error = ENOTTY;
		break;
	}
	return error;
}


/*
 * Load the label information on the named device
 */
int
sdgetdisklabel(u_char unit)
{
	struct sd_data *sd = sd_data[unit];
	/*unsigned int n, m;*/
	char *errstring;
	struct cpu_disklabel osdep;

	/* If the inflo is already loaded, use it */
	if(sd->flags & SDHAVELABEL)
		return ESUCCESS;

	bzero(&sd->disklabel, sizeof(struct disklabel));
	/*
	 * make partition 3 the whole disk in case of failure
	 * then get pdinfo
	 */
	sd->disklabel.d_partitions[0].p_offset = 0;
	sd->disklabel.d_partitions[0].p_size = sd->params.disksize;
	sd->disklabel.d_partitions[RAW_PART].p_offset = 0;
	sd->disklabel.d_partitions[RAW_PART].p_size = sd->params.disksize;
	sd->disklabel.d_npartitions = MAXPARTITIONS;
	sd->disklabel.d_secsize = SECSIZE; /* as long as it's not 0 */
	sd->disklabel.d_ntracks = sd->params.heads;
	sd->disklabel.d_nsectors = sd->params.sectors;
	sd->disklabel.d_ncylinders = sd->params.cyls;
	sd->disklabel.d_secpercyl = sd->params.heads * sd->params.sectors;
	if (sd->disklabel.d_secpercyl == 0) {
		/* as long as it's not 0 because readdisklabel() divides by it */
		sd->disklabel.d_secpercyl = 100;
	}

	/* all the generic disklabel extraction routine */
	if(errstring = readdisklabel(makedev(0 ,(unit<<UNITSHIFT )+3),
	    sdstrategy, &sd->disklabel, &sd->cpudisklabel)) {
		printf("sd%d: %s\n",unit, errstring);
		return ENXIO;
	}

	/* leave partition 2 "open" for raw I/O */

	sd->flags |= SDHAVELABEL;	/* WE HAVE IT ALL NOW */
	return ESUCCESS;
}

/*
 * Find out from the device what it's capacity is
 */
int
sd_size(int unit, int flags)
{
	struct scsi_read_cap_data rdcap;
	struct scsi_read_capacity scsi_cmd;
	int size;

	/*
	 * make up a scsi command and ask the scsi driver to do
	 * it for you.
	 */
	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.op_code = READ_CAPACITY;

	/*
	 * If the command works, interpret the result as a 4 byte
	 * number of blocks
	 */
	if (sd_scsi_cmd(unit, (struct scsi_generic *)&scsi_cmd,
	    sizeof(scsi_cmd), (u_char *)&rdcap, sizeof(rdcap), 2000, flags) != 0) {
		printf("could not get size of unit %d\n", unit);
		return 0;
	} else {
		size = rdcap.addr_0 + 1 ;
		size += rdcap.addr_1 << 8;
		size += rdcap.addr_2 << 16;
		size += rdcap.addr_3 << 24;
	}
	return size;
}
	
/*
 * Get scsi driver to send a "are you ready?" command
 */
int
sd_test_unit_ready(int unit, int flags)
{
	struct	scsi_test_unit_ready scsi_cmd;

	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.op_code = TEST_UNIT_READY;

	return sd_scsi_cmd(unit, (struct scsi_generic *)&scsi_cmd,
	    sizeof(scsi_cmd), 0, 0, 100000, flags);
}

/*
 * format disk
 */
int
sd_format(int unit, struct scsi_format_parms *f, int flags, int type)
{
	struct scsi_prevent scsi_cmd;

	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.op_code = FORMAT_DISK;
	scsi_cmd.prevent=  type;
	return sd_scsi_cmd(unit, (struct scsi_generic *)&scsi_cmd,
	    sizeof(scsi_cmd), (u_char *)f, sizeof *f, 500000000, flags);
}

/*
 * Prevent or allow the user to remove the tape
 */
int
sd_prevent(int unit, int type, int flags)
{
	struct	scsi_prevent	scsi_cmd;

	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.op_code = PREVENT_ALLOW;
	scsi_cmd.prevent=type;
	return sd_scsi_cmd(unit, (struct scsi_generic *)&scsi_cmd,
	    sizeof(scsi_cmd), 0, 0, 5000, flags);
}

/*
 * Get scsi driver to send a "start up" command
 */
int 
sd_start_unit(int unit, int flags)
{
	struct scsi_start_stop scsi_cmd;

	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.op_code = START_STOP;
	scsi_cmd.start = 1;

	return sd_scsi_cmd(unit, (struct scsi_generic *)&scsi_cmd,
	    sizeof(scsi_cmd), 0, 0, 2000, flags);
}

/*
 * Tell the device to map out a defective block
 */
int 
sd_reassign_blocks(int unit, int block)
{
	struct scsi_reassign_blocks_data rbdata;
	struct scsi_reassign_blocks scsi_cmd;

	bzero(&scsi_cmd, sizeof(scsi_cmd));
	bzero(&rbdata, sizeof(rbdata));
	scsi_cmd.op_code = REASSIGN_BLOCKS;

	rbdata.length_msb = 0;
	rbdata.length_lsb = sizeof(rbdata.defect_descriptor[0]);
	rbdata.defect_descriptor[0].dlbaddr_3 = ((block >> 24) & 0xff);
	rbdata.defect_descriptor[0].dlbaddr_2 = ((block >> 16) & 0xff);
	rbdata.defect_descriptor[0].dlbaddr_1 = ((block >>  8) & 0xff);
	rbdata.defect_descriptor[0].dlbaddr_0 = ((block      ) & 0xff);

	return sd_scsi_cmd(unit, (struct scsi_generic *)&scsi_cmd,
	    sizeof(scsi_cmd), (u_char *)&rbdata, sizeof(rbdata), 5000, 0);
}

#define b2tol(a)	(((unsigned)(a##_1) << 8) + (unsigned)a##_0 )

/*
 * Get the scsi driver to send a full inquiry to the
 * device and use the results to fill out the disk
 * parameter structure.
 */
int
sd_get_parms(int unit, int flags)
{
	struct sd_data *sd = sd_data[unit];
	struct disk_parms *disk_parms = &sd->params;
	struct scsi_mode_sense	scsi_cmd;
	struct scsi_mode_sense_data {
		struct	scsi_mode_header header;
		struct	blk_desc blk_desc;
		union	disk_pages pages;
	} scsi_sense;
	int sectors;

	/* First check if we have it all loaded */
	if(!sd)
		return 0;
	if(sd->flags & SDVALID)
		return 0;

	/* First do a mode sense page 3 */
	if (sd_debug) {
		bzero(&scsi_cmd, sizeof(scsi_cmd));
		scsi_cmd.op_code = MODE_SENSE;
		scsi_cmd.page_code = 3;
		scsi_cmd.length = 0x24;

		/*
		 * do the command, but we don't need the results
		 * just print them for our interest's sake
		 */
		if (sd_scsi_cmd(unit, (struct scsi_generic *)&scsi_cmd,
		    sizeof(scsi_cmd), (u_char *)&scsi_sense, sizeof(scsi_sense),
		    2000, flags) != 0) {
			printf("could not mode sense (3) for unit %d\n", unit);
			return ENXIO;
		} 
		printf("unit %d: %d trk/zn, %d altsec/zn, %d alttrk/zn, %d alttrk/lun\n",
			unit, b2tol(scsi_sense.pages.disk_format.trk_z),
			b2tol(scsi_sense.pages.disk_format.alt_sec),
			b2tol(scsi_sense.pages.disk_format.alt_trk_z),
			b2tol(scsi_sense.pages.disk_format.alt_trk_v));
		printf("  %d sec/trk, %d byte/sec, %d interleave, %d %d bytes/log_blk\n",
			b2tol(scsi_sense.pages.disk_format.ph_sec_t),
			b2tol(scsi_sense.pages.disk_format.bytes_s),
			b2tol(scsi_sense.pages.disk_format.interleave),
			sd_size(unit, flags),
			_3btol((u_char *)scsi_sense.blk_desc.blklen));
	}


	/* do a "mode sense page 4" */
	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.op_code = MODE_SENSE;
	scsi_cmd.page_code = 4;
	scsi_cmd.length = 0x20;

	/*
	 * If the command worked, use the results to fill out
	 * the parameter structure
	 */
	if (sd_scsi_cmd(unit, (struct scsi_generic *)&scsi_cmd,
	    sizeof(scsi_cmd), (u_char *)&scsi_sense, sizeof(scsi_sense),
	    2000, flags) != 0) {
		printf("could not mode sense (4) for unit %d\n", unit);
		printf(" using ficticious geometry\n");
		sectors = sd_size(unit, flags);
		disk_parms->heads = 64;
		disk_parms->sectors = 32;
		disk_parms->cyls = sectors/(64 * 32);
		disk_parms->secsiz = SECSIZE;
	} else {
		if (sd_debug) {
			printf("  %d cyl, %d head, %d precomp, %d redwrite, %d land\n",
			_3btol((u_char *)&scsi_sense.pages.rigid_geometry.ncyl_2),
			scsi_sense.pages.rigid_geometry.nheads,
			b2tol(scsi_sense.pages.rigid_geometry.st_cyl_wp),
			b2tol(scsi_sense.pages.rigid_geometry.st_cyl_rwc),
			b2tol(scsi_sense.pages.rigid_geometry.land_zone));
		}

		/*
		 * KLUDGE!!(for zone recorded disks)
		 * give a number of sectors so that sec * trks * cyls
		 * is <= disk_size
		 */
		disk_parms->heads = scsi_sense.pages.rigid_geometry.nheads;
		disk_parms->cyls =
			_3btol((u_char *)&scsi_sense.pages.rigid_geometry.ncyl_2);
		disk_parms->secsiz = _3btol((u_char *)&scsi_sense.blk_desc.blklen);

		sectors = sd_size(unit, flags);
		sectors /= disk_parms->cyls;
		sectors /= disk_parms->heads;
		disk_parms->sectors = sectors; /* dubious on SCSI*/
	}

	disk_parms->disksize = disk_parms->sectors * disk_parms->heads *
		disk_parms->cyls;
	sd->flags |= SDVALID;
	return 0;
}

/*
 * close the device.. only called if we are the LAST
 * occurence of an open device
 */
int
sdclose(dev_t dev)
{
	struct sd_data *sd;
	unsigned char unit, part;
	unsigned int old_priority;

	unit = UNIT(dev);
	part = PARTITION(dev);
	sd = sd_data[unit];
	sd->partflags[part] &= ~SDOPEN;
	sd->openparts &= ~(1 << part);
	if(sd->openparts == 0)
		sd_prevent(unit, PR_ALLOW, SCSI_SILENT|SCSI_ERR_OK);
	return 0;
}

/*
 * ask the scsi driver to perform a command for us.
 * Call it through the switch table, and tell it which
 * sub-unit we want, and what target and lu we wish to
 * talk to. Also tell it where to find the command
 * how long int is.
 * Also tell it where to read/write the data, and how
 * long the data is supposed to be
 */
int
sd_scsi_cmd(int unit, struct scsi_generic *scsi_cmd, int cmdlen,
	u_char *data_addr, int datalen, int timeout, int flags)
{
	struct sd_data *sd = sd_data[unit];
	struct	scsi_xfer *xs;
	int retval, s;

	if(scsi_debug & PRINTROUTINES)
		printf("\nsd_scsi_cmd%d ",unit);
	if(!sd->sc_sw) {
		printf("sd%d: not set up\n",unit);
		return EINVAL;
	}

	xs = sd_get_xs(unit,flags); /* should wait unless booting */
	if(!xs) {
		printf("sd_scsi_cmd%d: controller busy"
 				" (this should never happen)\n",unit); 
		return EBUSY;
	}

	xs->flags |= INUSE;
	xs->flags	|=	flags;
	xs->adapter =	sd->ctlr;
	xs->targ =	sd->targ;
	xs->lu =	sd->lu;
	xs->retries =	SD_RETRIES;
	xs->timeout =	timeout;
	xs->cmd =	scsi_cmd;
	xs->cmdlen =	cmdlen;
	xs->data =	data_addr;
	xs->datalen =	datalen;
	xs->resid =	datalen;
	xs->when_done =	(flags & SCSI_NOMASK) ?(int (*)())0 : sd_done;
	xs->done_arg =	unit;
	xs->done_arg2 =	(int)xs;

retry:
	xs->error =	XS_NOERROR;
	xs->bp =	0;
	retval = (*(sd->sc_sw->scsi_cmd))(xs);
	switch(retval) {
	case SUCCESSFULLY_QUEUED:
		s = splbio();
		while(!(xs->flags & ITSDONE))
			tsleep((caddr_t)xs, PRIBIO+1, "sd_cmd", 0);
		splx(s);
	case HAD_ERROR:
		/*printf("err = %d ", xs->error);*/
		switch(xs->error) {
		case XS_NOERROR:
			retval = ESUCCESS;
			break;
		case XS_SENSE:
			retval = sd_interpret_sense(unit, xs);
			break;
		case XS_DRIVER_STUFFUP:
			retval = EIO;
			break;
		case XS_TIMEOUT:
		case XS_BUSY:
			if(xs->retries-- ) {
				xs->flags &= ~ITSDONE;
				goto retry;
			}
			retval = EIO;
			break;
		default:
			retval = EIO;
			printf("sd%d: unknown error category from scsi driver\n", unit);
		}	
		break;
	case COMPLETE:
		retval = ESUCCESS;
		break;
	case 	TRY_AGAIN_LATER:
		if(xs->retries-- ) {
			xs->flags &= ~ITSDONE;
			goto retry;
		}
		retval = EIO;
		break;
	default:
		retval = EIO;
	}

	sd_free_xs(unit, xs, flags);
	sdstart(unit);			/* check if anything is waiting fr the xs */
	return retval;
}

/*
 * Look at the returned sense and act on the error and detirmine
 * The unix error number to pass back... (0 = report no error)
 */
int
sd_interpret_sense(int unit, struct scsi_xfer *xs)
{
	struct sd_data *sd = sd_data[unit];
	struct scsi_sense_data *sense;
	int key, silent;

	/* If the flags say errs are ok, then always return ok. */
	if (xs->flags & SCSI_ERR_OK)
		return ESUCCESS;
	silent = (xs->flags & SCSI_SILENT);

	sense = &(xs->sense);
	switch(sense->error_class) {
	case 7:
		key = sense->ext.extended.sense_key;
		switch(key) {
		case 0x0:
			return ESUCCESS;
		case 0x1:
			if(!silent) {
				printf("sd%d: soft error(corrected) ", unit); 
				if(sense->valid) {
			  		printf("block no. %d (decimal)",
				  		(sense->ext.extended.info[0] <<24) |
				  		(sense->ext.extended.info[1] <<16) |
				  		(sense->ext.extended.info[2] <<8) |
				  		(sense->ext.extended.info[3] ));
				}
				printf("\n");
			}
			return ESUCCESS;
		case 0x2:
			if(!silent)
				printf("sd%d: not ready\n ", unit); 
			return ENODEV;
		case 0x3:
			if(!silent) {
				printf("sd%d: medium error ", unit); 
				if(sense->valid) {
			  		printf("block no. %d (decimal)",
				  		(sense->ext.extended.info[0] <<24) |
				  		(sense->ext.extended.info[1] <<16) |
				  		(sense->ext.extended.info[2] <<8) |
				  		(sense->ext.extended.info[3] ));
				}
				printf("\n");
			}
			return EIO;
		case 0x4:
			if(!silent)
				printf("sd%d: non-media hardware failure\n ", unit); 
			return EIO;
		case 0x5:
			if(!silent)
				printf("sd%d: illegal request\n ", unit); 
			return EINVAL;
		case 0x6:
			/*
			 * If we are not open, then this is not an error
			 * as we don't have state yet. Either way, make
			 * sure that we don't have any residual state
			 */
			if(!silent)
				printf("sd%d: reset\n", unit); 
			sd->flags &= ~(SDVALID | SDHAVELABEL);
			if (sd->openparts)
				return EIO;
			return ESUCCESS;	/* not an error if nothing's open */
		case 0x7:
			if(!silent) {
				printf("sd%d: attempted protection violation ", unit); 
				if(sense->valid) {
					printf("block no. %d (decimal)\n",
				  		(sense->ext.extended.info[0] <<24) |
				  		(sense->ext.extended.info[1] <<16) |
				  		(sense->ext.extended.info[2] <<8) |
				  		(sense->ext.extended.info[3] ));
				}
				printf("\n");
			}
			return EACCES;
		case 0x8:
			if(!silent) {
				printf("sd%d: block wrong state (worm)\n ", unit); 
				if(sense->valid) {
			  		printf("block no. %d (decimal)\n",
				  		(sense->ext.extended.info[0] <<24) |
				  		(sense->ext.extended.info[1] <<16) |
				  		(sense->ext.extended.info[2] <<8) |
				  		(sense->ext.extended.info[3] ));
				}
				printf("\n");
			}
			return EIO;
		case 0x9:
			if(!silent)
				printf("sd%d: vendor unique\n", unit); 
			return EIO;
		case 0xa:
			if(!silent)
				printf("sd%d: copy aborted\n ", unit); 
			return EIO;
		case 0xb:
			if(!silent)
				printf("sd%d: command aborted\n ", unit); 
			return EIO;
		case 0xc:
			if(!silent) {
				printf("sd%d: search returned\n ", unit); 
				if(sense->valid) {
			  		printf("block no. %d (decimal)\n",
				  		(sense->ext.extended.info[0] <<24) |
				  		(sense->ext.extended.info[1] <<16) |
				  		(sense->ext.extended.info[2] <<8) |
				  		(sense->ext.extended.info[3] ));
				}
				printf("\n");
			}
			return ESUCCESS;
		case 0xd:
			if(!silent)
				printf("sd%d: volume overflow\n ", unit); 
			return ENOSPC;
		case 0xe:
			if(!silent) {
				printf("sd%d: verify miscompare\n ", unit); 
				if(sense->valid) {
			  		printf("block no. %d (decimal)\n",
				  		(sense->ext.extended.info[0] <<24) |
				  		(sense->ext.extended.info[1] <<16) |
				  		(sense->ext.extended.info[2] <<8) |
				  		(sense->ext.extended.info[3] ));
				}
				printf("\n");
			}
			return EIO;
		case 0xf:
			if(!silent)
				printf("sd%d: unknown error key\n ", unit); 
			return EIO;
		}
		break;
	case 0:
	case 1:
	case 2:
	case 3:
	case 4:
	case 5:
	case 6:
		if(!silent)printf("sd%d: error class %d code %d\n", unit,
			sense->error_class, sense->error_code);
		if(sense->valid)
			if(!silent)
				printf("block no. %d (decimal)\n",
					(sense->ext.unextended.blockhi <<16)
					+ (sense->ext.unextended.blockmed <<8)
					+ (sense->ext.unextended.blocklow ));
		return EIO;
	}
	return 0;		/* XXX? */
}

int
sdsize(dev_t dev)
{
	int unit = UNIT(dev), part = PARTITION(dev), val;
	struct sd_data *sd;

	if (unit >= NSD)
		return -1;
	if(!sd_data[unit])
		return -1;

	sd = sd_data[unit];
	if((sd->flags & SDINIT) == 0)
		return -1;

	if( sd==0 || (sd->flags & SDHAVELABEL)==0 )
		val = sdopen(MAKESDDEV(major(dev), unit, RAW_PART));
	if ( val!=0 || sd->flags & SDWRITEPROT)
		return -1;

	return (int)sd->disklabel.d_partitions[part].p_size;
}

sddump()
{
	printf("sddump() -- not implemented\n");
	return -1;
}