partial sync with netbsd 960418, more to come

1 files changed, 493 insertions, 336 deletions

diff --git a/sys/scsi/ch.c b/sys/scsi/ch.c
index a99dc2ad7b5..811bb057fb2 100644
--- a/sys/scsi/ch.c
+++ b/sys/scsi/ch.c
@@ -1,8 +1,13 @@
-/*	$OpenBSD: ch.c,v 1.3 1996/04/19 16:10:12 niklas Exp $	*/
-/*	$NetBSD: ch.c,v 1.16 1996/03/05 00:15:09 thorpej Exp $	*/
+/*	$OpenBSD: ch.c,v 1.4 1996/04/21 22:30:45 deraadt Exp $	*/
+/*	$NetBSD: ch.c,v 1.20 1996/04/03 00:25:39 thorpej Exp $	*/
 
 /*
- * Copyright (c) 1994 Charles Hannum.  All rights reserved.
+ * Copyright (c) 1996 Jason R. Thorpe <thorpej@and.com>
+ * All rights reserved.
+ *
+ * Partially based on an autochanger driver written by Stefan Grefen
+ * and on an autochanger driver written by the Systems Programming Group
+ * at the University of Utah Computer Science Department.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -13,8 +18,9 @@
  *    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 Charles Hannum.
+ *    must display the following acknowledgements:
+ *	This product includes software developed by Jason R. Thorpe
+ *	for And Communications, http://www.and.com/
  * 4. The name of the author may not be used to endorse or promote products
  *    derived from this software without specific prior written permission.
  *
@@ -22,20 +28,15 @@
  * 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 AUTHOR 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.
- */
-
-/* 
- * Originally written by grefen@?????
- * Based on scsi drivers by Julian Elischer (julian@tfs.com)
+ * 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.
  */
 
-#include <sys/types.h>
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/errno.h>
@@ -43,63 +44,76 @@
 #include <sys/buf.h>
 #include <sys/proc.h>
 #include <sys/user.h>
-#include <sys/chio.h>
+#include <sys/chio.h> 
 #include <sys/device.h>
+#include <sys/malloc.h>
 
 #include <scsi/scsi_all.h>
 #include <scsi/scsi_changer.h>
 #include <scsi/scsiconf.h>
-#include <scsi/scsi_conf.h>
 
-#define	CHRETRIES	2
-
-#define CHMODE(z)	(minor(z) & 0x0f)
-#define CHUNIT(z)	(minor(z) >> 4)
+#define CHRETRIES	2
+#define CHUNIT(x)	(minor((x)))
 
 struct ch_softc {
-	struct device sc_dev;
-
-	struct scsi_link *sc_link;	/* all the inter level info */
-	u_int16_t chmo;			/* Offset of first CHM */
-	u_int16_t chms;			/* No. of CHM */
-	u_int16_t slots;		/* No. of Storage Elements */
-	u_int16_t sloto;		/* Offset of first SE */
-	u_int16_t imexs;		/* No. of Import/Export Slots */
-	u_int16_t imexo;		/* Offset of first IM/EX */
-	u_int16_t drives;		/* No. of CTS */
-	u_int16_t driveo;		/* Offset of first CTS */
-	u_int16_t rot;			/* CHM can rotate */
-	u_long  op_matrix;		/* possible operations */
-	u_int16_t lsterr;		/* details of lasterror */
-	u_char  stor;			/* posible Storage locations */
+	struct device	sc_dev;		/* generic device info */
+	struct scsi_link *sc_link;	/* link in the SCSI bus */
+
+	int		sc_picker;	/* current picker */
+
+	/*
+	 * The following information is obtained from the
+	 * element address assignment page.
+	 */
+	int		sc_firsts[4];	/* firsts, indexed by CHET_* */
+	int		sc_counts[4];	/* counts, indexed by CHET_* */
+
+	/*
+	 * The following mask defines the legal combinations
+	 * of elements for the MOVE MEDIUM command.
+	 */
+	u_int8_t	sc_movemask[4];
+
+	/*
+	 * As above, but for EXCHANGE MEDIUM.
+	 */
+	u_int8_t	sc_exchangemask[4];
+
+	int		flags;		/* misc. info */
 };
 
+/* sc_flags */
+#define CHF_ROTATE	0x01		/* picker can rotate */
+
+/* Autoconfiguration glue */
 int	chmatch __P((struct device *, void *, void *));
 void	chattach __P((struct device *, struct device *, void *));
-int	ch_getelem __P((struct ch_softc *, short *, int, int , char *, int));
-int	ch_move __P((struct ch_softc *, short *, int, int , int , int ));
-int	ch_position __P((struct ch_softc *, short *, int, int , int ));
-int	ch_mode_sense __P((struct ch_softc *, int));
 
-struct cfdriver chcd = {
-	NULL, "ch", chmatch, chattach, DV_DULL, sizeof(struct ch_softc)
+struct cfattach ch_ca = {
+	sizeof(struct ch_softc), chmatch, chattach
 };
 
-/*
- * This driver is so simple it uses all the default services
- */
-struct scsi_device ch_switch = {
-	NULL,
-	NULL,
-	NULL,
-	NULL,
+struct cfdriver ch_cd = {
+	NULL, "ch", DV_DULL
 };
 
 struct scsi_inquiry_pattern ch_patterns[] = {
 	{T_CHANGER, T_REMOV,
-	 "",         "",                 ""},
+	 "",		"",		""},
 };
 
+/* SCSI glue */
+struct scsi_device ch_switch = {
+	NULL, NULL, NULL, NULL
+};
+
+int	ch_move __P((struct ch_softc *, struct changer_move *));
+int	ch_exchange __P((struct ch_softc *, struct changer_exchange *));
+int	ch_position __P((struct ch_softc *, struct changer_position *));
+int	ch_usergetelemstatus __P((struct ch_softc *, int, u_int8_t *));
+int	ch_getelemstatus __P((struct ch_softc *, int, int, caddr_t, size_t));
+int	ch_get_params __P((struct ch_softc *, int));
+
 int
 chmatch(parent, match, aux)
 	struct device *parent;
@@ -111,366 +125,509 @@ chmatch(parent, match, aux)
 	(void)scsi_inqmatch(sa->sa_inqbuf,
 	    (caddr_t)ch_patterns, sizeof(ch_patterns)/sizeof(ch_patterns[0]),
 	    sizeof(ch_patterns[0]), &priority);
+
 	return (priority);
 }
 
-/*
- * The routine called by the low level scsi routine when it discovers
- * a device suitable for this driver.
- */
-void 
+void
 chattach(parent, self, aux)
 	struct device *parent, *self;
 	void *aux;
 {
-	struct ch_softc *ch = (void *)self;
+	struct ch_softc *sc = (struct ch_softc *)self;
 	struct scsibus_attach_args *sa = aux;
-	struct scsi_link *sc_link = sa->sa_sc_link;
+	struct scsi_link *link = sa->sa_sc_link;
 
-	SC_DEBUG(sc_link, SDEV_DB2, ("chattach: "));
+	/* Glue into the SCSI bus */
+	sc->sc_link = link;
+	link->device = &ch_switch;
+	link->device_softc = sc;
+	link->openings = 1;
 
-	/*
-	 * Store information needed to contact our base driver
-	 */
-	ch->sc_link = sc_link;
-	sc_link->device = &ch_switch;
-	sc_link->device_softc = ch;
-	sc_link->openings = 1;
+	printf("\n");
 
 	/*
-	 * Use the subdriver to request information regarding
-	 * the drive. We cannot use interrupts yet, so the
-	 * request must specify this.
+	 * Get information about the device.  Note we can't use
+	 * interrupts yet.
 	 */
-	printf("\n");
-	printf("%s: ", ch->sc_dev.dv_xname);
-	if (ch_mode_sense(ch, SCSI_AUTOCONF) != 0)
-		printf("offline\n");
-	else
-		printf("%d slot(s), %d drive(s), %d arm(s), %d i/e-slot(s)\n",
-		    ch->slots, ch->drives, ch->chms, ch->imexs);
+	if (ch_get_params(sc, SCSI_AUTOCONF))
+		printf("%s: offline\n", sc->sc_dev.dv_xname);
+	else {
+		printf("%s: %d slot%s, %d drive%s, %d picker%s",
+		    sc->sc_dev.dv_xname,
+		    sc->sc_counts[CHET_ST], (sc->sc_counts[CHET_ST] > 1) ?
+		    "s" : "",
+		    sc->sc_counts[CHET_DT], (sc->sc_counts[CHET_DT] > 1) ?
+		    "s" : "",
+		    sc->sc_counts[CHET_MT], (sc->sc_counts[CHET_MT] > 1) ?
+		    "s" : "");
+		if (sc->sc_counts[CHET_IE])
+			printf(", %d portal%s", sc->sc_counts[CHET_IE],
+			    (sc->sc_counts[CHET_IE] > 1) ? "s" : "");
+		printf("\n");
+#ifdef CHANGER_DEBUG
+		printf("%s: move mask: 0x%x 0x%x 0x%x 0x%x\n",
+		    sc->sc_dev.dv_xname,
+		    sc->sc_movemask[CHET_MT], sc->sc_movemask[CHET_ST],
+		    sc->sc_movemask[CHET_IE], sc->sc_movemask[CHET_DT]);
+		printf("%s: exchange mask: 0x%x 0x%x 0x%x 0x%x\n",
+		    sc->sc_dev.dv_xname,
+		    sc->sc_exchangemask[CHET_MT], sc->sc_exchangemask[CHET_ST],
+		    sc->sc_exchangemask[CHET_IE], sc->sc_exchangemask[CHET_DT]);
+#endif /* CHANGER_DEBUG */
+	}
+
+	/* Default the current picker. */
+	sc->sc_picker = sc->sc_firsts[CHET_MT];
 }
 
-/*
- *    open the device.
- */
-int 
-chopen(dev, flags, mode, p)
+int
+chopen(dev, flags, fmt, p)
 	dev_t dev;
-	int flags;
-	int mode;
+	int flags, fmt;
 	struct proc *p;
 {
-	int error = 0;
-	int unit;
-	struct ch_softc *ch;
-	struct scsi_link *sc_link;
+	struct ch_softc *sc;
+	int unit, error = 0;
 
 	unit = CHUNIT(dev);
-	if (unit >= chcd.cd_ndevs)
-		return ENXIO;
-	ch = chcd.cd_devs[unit];
-	if (!ch)
-		return ENXIO;
-
-	sc_link = ch->sc_link;
-
-	SC_DEBUG(sc_link, SDEV_DB1,
-	    ("chopen: dev=0x%x (unit %d (of %d))\n", dev, unit, chcd.cd_ndevs));
+	if ((unit >= ch_cd.cd_ndevs) ||
+	    ((sc = ch_cd.cd_devs[unit]) == NULL))
+		return (ENXIO);
 
 	/*
-	 * Only allow one at a time
+	 * Only allow one open at a time.
 	 */
-	if (sc_link->flags & SDEV_OPEN) {
-		printf("%s: already open\n", ch->sc_dev.dv_xname);
-		return EBUSY;
-	}
+	if (sc->sc_link->flags & SDEV_OPEN)
+		return (EBUSY);
+
+	sc->sc_link->flags |= SDEV_OPEN;
 
 	/*
-	 * Catch any unit attention errors.
+	 * Absorb any unit attention errors.  Ignore "not ready"
+	 * since this might occur if e.g. a tape isn't actually
+	 * loaded in the drive.
 	 */
-	error = scsi_test_unit_ready(sc_link, SCSI_IGNORE_MEDIA_CHANGE);
-	if (error)
+	if (error = scsi_test_unit_ready(sc->sc_link,
+	    SCSI_IGNORE_NOT_READY|SCSI_IGNORE_MEDIA_CHANGE))
 		goto bad;
 
-	sc_link->flags |= SDEV_OPEN;	/* unit attn are now errors */
-
 	/*
-	 * Make sure data is loaded
+	 * Make sure our parameters are up to date.
 	 */
-	if ((error = ch_mode_sense(ch, 0)) != 0) {
-		printf("%s: offline\n", ch->sc_dev.dv_xname);
+	if (error = ch_get_params(sc, 0))
 		goto bad;
-	}
 
-	SC_DEBUG(sc_link, SDEV_DB3, ("open complete\n"));
-	return 0;
+	return (0);
 
-bad:
-	sc_link->flags &= ~SDEV_OPEN;
-	return error;
+ bad:
+	sc->sc_link->flags &= ~SDEV_OPEN;
+	return (error);
 }
 
-/*
- * close the device.. only called if we are the LAST
- * occurence of an open device
- */
-int 
-chclose(dev, flags, mode, p)
+int
+chclose(dev, flags, fmt, p)
 	dev_t dev;
-	int flags;
-	int mode;
+	int flags, fmt;
 	struct proc *p;
 {
-	struct ch_softc *ch = chcd.cd_devs[CHUNIT(dev)];
-
-	SC_DEBUG(ch->sc_link, SDEV_DB1, ("closing\n"));
-	ch->sc_link->flags &= ~SDEV_OPEN;
+	struct ch_softc *sc = ch_cd.cd_devs[CHUNIT(dev)];
 
-	return 0;
+	sc->sc_link->flags &= ~SDEV_OPEN;
+	return (0);
 }
 
-/*
- * Perform special action on behalf of the user
- * Knows about the internals of this device
- */
-int 
-chioctl(dev, cmd, arg, mode, p)
+int
+chioctl(dev, cmd, data, flags, p)
 	dev_t dev;
 	u_long cmd;
-	caddr_t arg;
-	int mode;
+	caddr_t data;
+	int flags;
 	struct proc *p;
 {
-	struct ch_softc *ch = chcd.cd_devs[CHUNIT(dev)];
-	struct scsi_link *sc_link = ch->sc_link;
-	int flags;
-
-	/*
-	 * Find the device that the user is talking about
-	 */
-	flags = 0;		/* give error messages, act on errors etc. */
+	struct ch_softc *sc = ch_cd.cd_devs[CHUNIT(dev)];
+	caddr_t elemdata;
+	int error = 0;
 
 	switch (cmd) {
-	case CHIOOP: {
-		struct chop *chop = (struct chop *) arg;
-		SC_DEBUG(sc_link, SDEV_DB2, ("[chtape_chop: %x]\n",
-		    chop->ch_op));
-
-		switch (chop->ch_op) {
-		case CHGETPARAM:
-			chop->u.getparam.chmo = ch->chmo;
-			chop->u.getparam.chms = ch->chms;
-			chop->u.getparam.sloto = ch->sloto;
-			chop->u.getparam.slots = ch->slots;
-			chop->u.getparam.imexo = ch->imexo;
-			chop->u.getparam.imexs = ch->imexs;
-			chop->u.getparam.driveo = ch->driveo;
-			chop->u.getparam.drives = ch->drives;
-			chop->u.getparam.rot = ch->rot;
-			chop->result = 0;
-			return 0;
-			break;
-		case CHPOSITION:
-			return ch_position(ch, &chop->result,
-			    chop->u.position.chm, chop->u.position.to, flags);
-		case CHMOVE:
-			return ch_move(ch, &chop->result, chop->u.position.chm,
-			    chop->u.move.from, chop->u.move.to, flags);
-		case CHGETELEM:
-			return ch_getelem(ch, &chop->result,
-			    chop->u.get_elem_stat.type,
-			    chop->u.get_elem_stat.from,
-			    (char *) &chop->u.get_elem_stat.elem_data, flags);
-		default:
-			return EINVAL;
-		}
-	}
+	case CHIOMOVE:
+		error = ch_move(sc, (struct changer_move *)data);
+		break;
+
+	case CHIOEXCHANGE:
+		error = ch_exchange(sc, (struct changer_exchange *)data);
+		break;
+
+	case CHIOPOSITION:
+		error = ch_position(sc, (struct changer_position *)data);
+		break;
+
+	case CHIOGPICKER:
+		*(int *)data = sc->sc_picker - sc->sc_firsts[CHET_MT];
+		break;
+
+	case CHIOSPICKER:	{
+		int new_picker = *(int *)data;
+
+		if (new_picker > (sc->sc_counts[CHET_MT] - 1))
+			return (EINVAL);
+		sc->sc_picker = sc->sc_firsts[CHET_MT] + new_picker;
+		break;		}
+
+	case CHIOGPARAMS:	{
+		struct changer_params *cp = (struct changer_params *)data;
+
+		cp->cp_curpicker = sc->sc_picker - sc->sc_firsts[CHET_MT];
+		cp->cp_npickers = sc->sc_counts[CHET_MT];
+		cp->cp_nslots = sc->sc_counts[CHET_ST];
+		cp->cp_nportals = sc->sc_counts[CHET_IE];
+		cp->cp_ndrives = sc->sc_counts[CHET_DT];
+		break;		}
+
+	case CHIOGSTATUS:	{
+		struct changer_element_status *ces =
+		    (struct changer_element_status *)data;
+
+		error = ch_usergetelemstatus(sc, ces->ces_type, ces->ces_data);
+		break;		}
+
+	/* Implement prevent/allow? */
+
 	default:
-		return scsi_do_ioctl(sc_link, dev, cmd, arg, mode, p);
+		error = scsi_do_ioctl(sc->sc_link, dev, cmd, data, flags, p);
+		break;
 	}
-#ifdef DIAGNOSTIC
-	panic("chioctl: impossible");
-#endif
+
+	return (error);
 }
 
-int 
-ch_getelem(ch, stat, type, from, data, flags)
-	struct ch_softc *ch;
-	short *stat;
-	int type, from;
-	char *data;
-	int flags;
+int
+ch_move(sc, cm)
+	struct ch_softc *sc;
+	struct changer_move *cm;
 {
-	struct scsi_read_element_status scsi_cmd;
-	char elbuf[32];
-	int error;
-
-	bzero(&scsi_cmd, sizeof(scsi_cmd));
-	scsi_cmd.opcode = READ_ELEMENT_STATUS;
-	scsi_cmd.byte2 = type;
-	scsi_cmd.starting_element_addr[0] = (from >> 8) & 0xff;
-	scsi_cmd.starting_element_addr[1] = from & 0xff;
-	scsi_cmd.number_of_elements[1] = 1;
-	scsi_cmd.allocation_length[2] = 32;
-
-	error = scsi_scsi_cmd(ch->sc_link, (struct scsi_generic *) &scsi_cmd,
-	    sizeof(scsi_cmd), (u_char *) elbuf, 32, CHRETRIES, 100000, NULL,
-	    SCSI_DATA_IN | flags);
-	if (error)
-		*stat = ch->lsterr;
-	else
-		*stat = 0;
-	bcopy(elbuf + 16, data, 16);
-	return error;
+	struct scsi_move_medium cmd;
+	u_int16_t fromelem, toelem;
+
+	/*
+	 * Check arguments.
+	 */
+	if ((cm->cm_fromtype > CHET_DT) || (cm->cm_totype > CHET_DT))
+		return (EINVAL);
+	if ((cm->cm_fromunit > (sc->sc_counts[cm->cm_fromtype] - 1)) ||
+	    (cm->cm_tounit > (sc->sc_counts[cm->cm_totype] - 1)))
+		return (ENODEV);
+
+	/*
+	 * Check the request against the changer's capabilities.
+	 */
+	if ((sc->sc_movemask[cm->cm_fromtype] & (1 << cm->cm_totype)) == 0)
+		return (EINVAL);
+
+	/*
+	 * Calculate the source and destination elements.
+	 */
+	fromelem = sc->sc_firsts[cm->cm_fromtype] + cm->cm_fromunit;
+	toelem = sc->sc_firsts[cm->cm_totype] + cm->cm_tounit;
+
+	/*
+	 * Build the SCSI command.
+	 */
+	bzero(&cmd, sizeof(cmd));
+	cmd.opcode = MOVE_MEDIUM;
+	_lto2b(sc->sc_picker, cmd.tea);
+	_lto2b(fromelem, cmd.src);
+	_lto2b(toelem, cmd.dst);
+	if (cm->cm_flags & CM_INVERT)
+		cmd.flags |= MOVE_MEDIUM_INVERT;
+
+	/*
+	 * Send command to changer.
+	 */
+	return (scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
+	    sizeof(cmd), NULL, 0, CHRETRIES, 100000, NULL, 0));
 }
 
-int 
-ch_move(ch, stat, chm, from, to, flags)
-	struct ch_softc *ch;
-	short *stat;
-	int chm, from, to, flags;
+int
+ch_exchange(sc, ce)
+	struct ch_softc *sc;
+	struct changer_exchange *ce;
 {
-	struct scsi_move_medium scsi_cmd;
-	int error;
-
-	bzero(&scsi_cmd, sizeof(scsi_cmd));
-	scsi_cmd.opcode = MOVE_MEDIUM;
-	scsi_cmd.transport_element_address[0] = (chm >> 8) & 0xff;
-	scsi_cmd.transport_element_address[1] = chm & 0xff;
-	scsi_cmd.source_address[0] = (from >> 8) & 0xff;
-	scsi_cmd.source_address[1] = from & 0xff;
-	scsi_cmd.destination_address[0] = (to >> 8) & 0xff;
-	scsi_cmd.destination_address[1] = to & 0xff;
-	scsi_cmd.invert = (chm & CH_INVERT) ? 1 : 0;
-	error = scsi_scsi_cmd(ch->sc_link, (struct scsi_generic *) &scsi_cmd,
-	    sizeof(scsi_cmd), NULL, 0, CHRETRIES, 100000, NULL, flags);
-	if (error)
-		*stat = ch->lsterr;
-	else
-		*stat = 0;
-	return error;
+	struct scsi_exchange_medium cmd;
+	u_int16_t src, dst1, dst2;
+
+	/*
+	 * Check arguments.
+	 */
+	if ((ce->ce_srctype > CHET_DT) || (ce->ce_fdsttype > CHET_DT) ||
+	    (ce->ce_sdsttype > CHET_DT))
+		return (EINVAL);
+	if ((ce->ce_srcunit > (sc->sc_counts[ce->ce_srctype] - 1)) ||
+	    (ce->ce_fdstunit > (sc->sc_counts[ce->ce_fdsttype] - 1)) ||
+	    (ce->ce_sdstunit > (sc->sc_counts[ce->ce_sdsttype] - 1)))
+		return (ENODEV);
+
+	/*
+	 * Check the request against the changer's capabilities.
+	 */
+	if (((sc->sc_exchangemask[ce->ce_srctype] &
+	     (1 << ce->ce_fdsttype)) == 0) ||
+	    ((sc->sc_exchangemask[ce->ce_fdsttype] &
+	     (1 << ce->ce_sdsttype)) == 0))
+		return (EINVAL);
+
+	/*
+	 * Calculate the source and destination elements.
+	 */
+	src = sc->sc_firsts[ce->ce_srctype] + ce->ce_srcunit;
+	dst1 = sc->sc_firsts[ce->ce_fdsttype] + ce->ce_fdstunit;
+	dst2 = sc->sc_firsts[ce->ce_sdsttype] + ce->ce_sdstunit;
+
+	/*
+	 * Build the SCSI command.
+	 */
+	bzero(&cmd, sizeof(cmd));
+	cmd.opcode = EXCHANGE_MEDIUM;
+	_lto2b(sc->sc_picker, cmd.tea);
+	_lto2b(src, cmd.src);
+	_lto2b(dst1, cmd.fdst);
+	_lto2b(dst2, cmd.sdst);
+	if (ce->ce_flags & CE_INVERT1)
+		cmd.flags |= EXCHANGE_MEDIUM_INV1;
+	if (ce->ce_flags & CE_INVERT2)
+		cmd.flags |= EXCHANGE_MEDIUM_INV2;
+
+	/*
+	 * Send command to changer.
+	 */
+	return (scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
+	    sizeof(cmd), NULL, 0, CHRETRIES, 100000, NULL, 0));
 }
 
-int 
-ch_position(ch, stat, chm, to, flags)
-	struct ch_softc *ch;
-	short *stat;
-	int chm, to, flags;
+int
+ch_position(sc, cp)
+	struct ch_softc *sc;
+	struct changer_position *cp;
 {
-	struct scsi_position_to_element scsi_cmd;
-	int error;
-
-	bzero(&scsi_cmd, sizeof(scsi_cmd));
-	scsi_cmd.opcode = POSITION_TO_ELEMENT;
-	scsi_cmd.transport_element_address[0] = (chm >> 8) & 0xff;
-	scsi_cmd.transport_element_address[1] = chm & 0xff;
-	scsi_cmd.source_address[0] = (to >> 8) & 0xff;
-	scsi_cmd.source_address[1] = to & 0xff;
-	scsi_cmd.invert = (chm & CH_INVERT) ? 1 : 0;
-	error = scsi_scsi_cmd(ch->sc_link, (struct scsi_generic *) &scsi_cmd,
-	    sizeof(scsi_cmd), NULL, 0, CHRETRIES, 100000, NULL, flags);
-	if (error)
-		*stat = ch->lsterr;
-	else
-		*stat = 0;
-	return error;
+	struct scsi_position_to_element cmd;
+	u_int16_t dst;
+
+	/*
+	 * Check arguments.
+	 */
+	if (cp->cp_type > CHET_DT)
+		return (EINVAL);
+	if (cp->cp_unit > (sc->sc_counts[cp->cp_type] - 1))
+		return (ENODEV);
+
+	/*
+	 * Calculate the destination element.
+	 */
+	dst = sc->sc_firsts[cp->cp_type] + cp->cp_unit;
+
+	/*
+	 * Build the SCSI command.
+	 */
+	bzero(&cmd, sizeof(cmd));
+	cmd.opcode = POSITION_TO_ELEMENT;
+	_lto2b(sc->sc_picker, cmd.tea);
+	_lto2b(dst, cmd.dst);
+	if (cp->cp_flags & CP_INVERT)
+		cmd.flags |= POSITION_TO_ELEMENT_INVERT;
+
+	/*
+	 * Send command to changer.
+	 */
+	return (scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
+	    sizeof(cmd), NULL, 0, CHRETRIES, 100000, NULL, 0));
 }
 
 /*
- * Get the scsi driver to send a full inquiry to the
- * device and use the results to fill out the global 
- * parameter structure.
+ * Perform a READ ELEMENT STATUS on behalf of the user, and return to
+ * the user only the data the user is interested in (i.e. an array of
+ * flags bytes).
  */
-int 
-ch_mode_sense(ch, flags)
-	struct ch_softc *ch;
-	int flags;
+int
+ch_usergetelemstatus(sc, chet, uptr)
+	struct ch_softc *sc;
+	int chet;
+	u_int8_t *uptr;
+{
+	struct read_element_status_header *st_hdr;
+	struct read_element_status_page_header *pg_hdr;
+	struct read_element_status_descriptor *desc;
+	caddr_t data = NULL;
+	size_t size, desclen;
+	int avail, i, error = 0;
+	u_int8_t *user_data = NULL;
+
+	/*
+	 * If there are no elements of the requested type in the changer,
+	 * the request is invalid.
+	 */
+	if (sc->sc_counts[chet] == 0)
+		return (EINVAL);
+
+	/*
+	 * Request one descriptor for the given element type.  This
+	 * is used to determine the size of the descriptor so that
+	 * we can allocate enough storage for all of them.  We assume
+	 * that the first one can fit into 1k.
+	 */
+	data = (caddr_t)malloc(1024, M_DEVBUF, M_WAITOK);
+	if (error = ch_getelemstatus(sc, sc->sc_firsts[chet], 1, data, 1024))
+		goto done;
+
+	st_hdr = (struct read_element_status_header *)data;
+	pg_hdr = (struct read_element_status_page_header *)((u_long)st_hdr +
+	    sizeof(struct read_element_status_header));
+	desclen = _2btol(pg_hdr->edl);
+
+	size = sizeof(struct read_element_status_header) +
+	    sizeof(struct read_element_status_page_header) +
+	    (desclen * sc->sc_counts[chet]);
+
+	/*
+	 * Reallocate storage for descriptors and get them from the
+	 * device.
+	 */
+	free(data, M_DEVBUF);
+	data = (caddr_t)malloc(size, M_DEVBUF, M_WAITOK);
+	if (error = ch_getelemstatus(sc, sc->sc_firsts[chet],
+	    sc->sc_counts[chet], data, size))
+		goto done;
+
+	/*
+	 * Fill in the user status array.
+	 */
+	st_hdr = (struct read_element_status_header *)data;
+	avail = _2btol(st_hdr->count);
+	if (avail != sc->sc_counts[chet])
+		printf("%s: warning, READ ELEMENT STATUS avail != count\n",
+		    sc->sc_dev.dv_xname);
+
+	user_data = (u_int8_t *)malloc(avail, M_DEVBUF, M_WAITOK);
+
+	desc = (struct read_element_status_descriptor *)((u_long)data +
+	    sizeof(struct read_element_status_header) +
+	    sizeof(struct read_element_status_page_header));
+	for (i = 0; i < avail; ++i) {
+		user_data[i] = desc->flags1;
+		(u_long)desc += desclen;
+	}
+
+	/* Copy flags array out to userspace. */
+	error = copyout(user_data, uptr, avail);
+
+ done:
+	if (data != NULL)
+		free(data, M_DEVBUF);
+	if (user_data != NULL)
+		free(user_data, M_DEVBUF);
+	return (error);
+}
+
+int
+ch_getelemstatus(sc, first, count, data, datalen)
+	struct ch_softc *sc;
+	int first, count;
+	caddr_t data;
+	size_t datalen;
 {
-	struct scsi_mode_sense scsi_cmd;
-	u_char scsi_sense[128];	/* Can't use scsi_mode_sense_data because of
-				 * missing block descriptor.
-				 */
-	u_char *b;
-	int i, l;
-	int error;
-	struct scsi_link *sc_link = ch->sc_link;
+	struct scsi_read_element_status cmd;
 
 	/*
-	 * First check if we have it all loaded
+	 * Build SCSI command.
 	 */
-	if (sc_link->flags & SDEV_MEDIA_LOADED)
-		return 0;
+	bzero(&cmd, sizeof(cmd));
+	cmd.opcode = READ_ELEMENT_STATUS;
+	_lto2b(first, cmd.sea);
+	_lto2b(count, cmd.count);
+	_lto3b(datalen, cmd.len);
 
 	/*
-	 * First do a mode sense 
+	 * Send command to changer.
 	 */
-	bzero(&scsi_cmd, sizeof(scsi_cmd));
-	scsi_cmd.opcode = MODE_SENSE;
-	scsi_cmd.byte2 = SMS_DBD;
-	scsi_cmd.page = 0x3f;	/* All Pages */
-	scsi_cmd.length = sizeof(scsi_sense);
+	return (scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
+	    sizeof(cmd), (u_char *)data, datalen, CHRETRIES, 100000, NULL, 0));
+}
+
+
+/*
+ * Ask the device about itself and fill in the parameters in our
+ * softc.
+ */
+int
+ch_get_params(sc, scsiflags)
+	struct ch_softc *sc;
+	int scsiflags;
+{
+	struct scsi_mode_sense cmd;
+	struct scsi_mode_sense_data {
+		struct scsi_mode_header header;
+		union {
+			struct page_element_address_assignment ea;
+			struct page_transport_geometry_parameters tg;
+			struct page_device_capabilities cap;
+		} pages;
+	} sense_data;
+	int error, from;
+	u_int8_t *moves, *exchanges;
 
 	/*
-	 * Read in the pages
+	 * Grab info from the element address assignment page.
 	 */
-	error = scsi_scsi_cmd(sc_link, (struct scsi_generic *) &scsi_cmd,
-			      sizeof(scsi_cmd), (u_char *) &scsi_sense,
-			      sizeof(scsi_sense), CHRETRIES, 5000, NULL,
-			      flags | SCSI_DATA_IN);
+	bzero(&cmd, sizeof(cmd));
+	bzero(&sense_data, sizeof(sense_data));
+	cmd.opcode = MODE_SENSE;
+	cmd.byte2 |= 0x08;	/* disable block descriptors */
+	cmd.page = 0x1d;
+	cmd.length = (sizeof(sense_data) & 0xff);
+	error = scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
+	    sizeof(cmd), (u_char *)&sense_data, sizeof(sense_data), CHRETRIES,
+	    6000, NULL, scsiflags | SCSI_DATA_IN);
 	if (error) {
-		printf("%s: could not mode sense\n", ch->sc_dev.dv_xname);
-		return error;
+		printf("%s: could not sense element address page\n");
+		return (error);
 	}
 
-	sc_link->flags |= SDEV_MEDIA_LOADED;
-	l = scsi_sense[0] - 3;
-	b = &scsi_sense[4];
+	sc->sc_firsts[CHET_MT] = _2btol(sense_data.pages.ea.mtea);
+	sc->sc_counts[CHET_MT] = _2btol(sense_data.pages.ea.nmte);
+	sc->sc_firsts[CHET_ST] = _2btol(sense_data.pages.ea.fsea);
+	sc->sc_counts[CHET_ST] = _2btol(sense_data.pages.ea.nse);
+	sc->sc_firsts[CHET_IE] = _2btol(sense_data.pages.ea.fieea);
+	sc->sc_counts[CHET_IE] = _2btol(sense_data.pages.ea.niee);
+	sc->sc_firsts[CHET_DT] = _2btol(sense_data.pages.ea.fdtea);
+	sc->sc_counts[CHET_DT] = _2btol(sense_data.pages.ea.ndte);
+
+	/* XXX ask for page trasport geom */
 
 	/*
-	 * To avoid alignment problems
+	 * Grab info from the capabilities page.
 	 */
-/* XXXX - FIX THIS FOR MSB */
-#define p2copy(valp)	 (valp[1] | (valp[0]<<8)); valp+=2
-#define p4copy(valp)	 (valp[3] | (valp[2]<<8) | (valp[1]<<16) | (valp[0]<<24)); valp+=4
-#if 0
-	printf("\nmode_sense %d\n", l);
-	for (i = 0; i < l + 4; i++)
-		printf("%x%c", scsi_sense[i], i % 8 == 7 ? '\n' : ':');
-	printf("\n");
-#endif
-	for (i = 0; i < l;) {
-		u_char pc = (*b++) & 0x3f;
-		u_char pl = *b++;
-		u_char *bb = b;
-		switch (pc) {
-		case 0x1d:
-			ch->chmo = p2copy(bb);
-			ch->chms = p2copy(bb);
-			ch->sloto = p2copy(bb);
-			ch->slots = p2copy(bb);
-			ch->imexo = p2copy(bb);
-			ch->imexs = p2copy(bb);
-			ch->driveo = p2copy(bb);
-			ch->drives = p2copy(bb);
-			break;
-		case 0x1e:
-			ch->rot = *b & 0x1;
-			break;
-		case 0x1f:
-			ch->stor = *b & 0xf;
-			bb += 2;
-			ch->stor = p4copy(bb);
-			break;
-		default:
-			break;
-		}
-		b += pl;
-		i += pl + 2;
+	bzero(&cmd, sizeof(cmd));
+	bzero(&sense_data, sizeof(sense_data));
+	cmd.opcode = MODE_SENSE;
+	cmd.byte2 |= 0x08;	/* disable block descriptors */
+	cmd.page = 0x1f;
+	cmd.length = (sizeof(sense_data) & 0xff);
+	error = scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
+	    sizeof(cmd), (u_char *)&sense_data, sizeof(sense_data), CHRETRIES,
+	    6000, NULL, scsiflags | SCSI_DATA_IN);
+	if (error) {
+		printf("%s: could not sense capabilities page\n");
+		return (error);
+	}
+
+	bzero(sc->sc_movemask, sizeof(sc->sc_movemask));
+	bzero(sc->sc_exchangemask, sizeof(sc->sc_exchangemask));
+	moves = &sense_data.pages.cap.move_from_mt;
+	exchanges = &sense_data.pages.cap.exchange_with_mt;
+	for (from = CHET_MT; from <= CHET_DT; ++from) {
+		sc->sc_movemask[from] = moves[from];
+		sc->sc_exchangemask[from] = exchanges[from];
 	}
-	SC_DEBUG(sc_link, SDEV_DB2,
-	    (" cht(%d-%d)slot(%d-%d)imex(%d-%d)cts(%d-%d) %s rotate\n",
-	    ch->chmo, ch->chms, ch->sloto, ch->slots, ch->imexo, ch->imexs,
-	    ch->driveo, ch->drives, ch->rot ? "can" : "can't"));
-	return 0;
+
+	sc->sc_link->flags |= SDEV_MEDIA_LOADED;
+	return (0);
 }