path: root/sys/dev/i2o/iopsp.c

/*	$OpenBSD: iopsp.c,v 1.4 2001/06/27 06:11:09 mickey Exp $	*/
/*	$NetBSD$	*/

/*-
 * Copyright (c) 2000, 2001 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Andrew Doran.
 *
 * 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 NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Raw SCSI device support for I2O.  IOPs present SCSI devices individually;
 * we group them by controlling port.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/queue.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/endian.h>
#include <sys/malloc.h>
#include <sys/scsiio.h>
#include <sys/lock.h>

#include <machine/bus.h>

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

#include <dev/i2o/i2o.h>
#include <dev/i2o/iopio.h>
#include <dev/i2o/iopvar.h>
#include <dev/i2o/iopspvar.h>

struct cfdriver iopsp_cd = {
	NULL, "iopsp", DV_DULL
};

int	iopsp_match(struct device *, void *, void *);
void	iopsp_attach(struct device *, struct device *, void *);

struct cfattach iopsp_ca = {
	sizeof(struct iopsp_softc), iopsp_match, iopsp_attach
};

int	iopsp_scsi_cmd __P((struct scsi_xfer *));
void	iopspminphys __P((struct buf *bp));

struct scsi_adapter iopsp_switch = {
	iopsp_scsi_cmd, iopspminphys, 0, 0,
};

struct scsi_device iopsp_dev = {
	NULL, NULL, NULL, NULL
};

void	iopsp_adjqparam(struct device *, int);
void	iopsp_intr(struct device *, struct iop_msg *, void *);
int	iopsp_rescan(struct iopsp_softc *);
int	iopsp_reconfig(struct device *);

/*
 * Match a supported device.
 */
int
iopsp_match(struct device *parent, void *match, void *aux)
{
	struct iop_attach_args *ia = aux;
	struct {
		struct	i2o_param_op_results pr;
		struct	i2o_param_read_results prr;
		struct	i2o_param_hba_ctlr_info ci;
	} __attribute__ ((__packed__)) param;
	int rv;

	if (ia->ia_class != I2O_CLASS_BUS_ADAPTER_PORT)
		return (0);

	if ((rv = iop_param_op((struct iop_softc *)parent, ia->ia_tid, NULL, 0,
	    I2O_PARAM_HBA_CTLR_INFO, &param, sizeof(param)))) {
#ifdef I2ODEBUG
		printf("iopsp_match: iop_param_op failed, status = %d\n", rv);
#endif
		return (0);
	}

#ifdef I2ODEBUG
	printf("iopsp_match: bustype = %d\n", param.ci.bustype);
#endif

	return (param.ci.bustype == I2O_HBA_BUS_SCSI ||
	    param.ci.bustype == I2O_HBA_BUS_FCA);
}

/*
 * Attach a supported device.
 */
void
iopsp_attach(struct device *parent, struct device *self, void *aux)
{
	struct iop_softc *iop = (struct iop_softc *)parent;
	struct iopsp_softc *sc = (struct iopsp_softc *)self;
	struct iop_attach_args *ia = (struct iop_attach_args *)aux;
	struct {
		struct	i2o_param_op_results pr;
		struct	i2o_param_read_results prr;
		union {
			struct	i2o_param_hba_ctlr_info ci;
			struct	i2o_param_hba_scsi_ctlr_info sci;
			struct	i2o_param_hba_scsi_port_info spi;
		} p;
	} __attribute__ ((__packed__)) param;
	int fcal, rv;
#ifdef I2OVERBOSE
	int size;
#endif

	/* Register us as an initiator. */
	sc->sc_ii.ii_dv = self;
	sc->sc_ii.ii_intr = iopsp_intr;
	sc->sc_ii.ii_flags = 0;
	sc->sc_ii.ii_tid = ia->ia_tid;
	sc->sc_ii.ii_reconfig = iopsp_reconfig;
	sc->sc_ii.ii_adjqparam = iopsp_adjqparam;
	iop_initiator_register(iop, &sc->sc_ii);

	rv = iop_param_op(iop, ia->ia_tid, NULL, 0, I2O_PARAM_HBA_CTLR_INFO,
	    &param, sizeof(param));
	if (rv != 0) {
		printf("%s: unable to get parameters (0x%04x; %d)\n",
	    	    sc->sc_dv.dv_xname, I2O_PARAM_HBA_CTLR_INFO, rv);
		goto bad;
	}

	fcal = (param.p.ci.bustype == I2O_HBA_BUS_FCA);		/* XXX */

	/* 
	 * Say what the device is.  If we can find out what the controling
	 * device is, say what that is too.
	 */
	printf(": SCSI port");
	iop_print_ident(iop, ia->ia_tid);
	printf("\n");

	rv = iop_param_op(iop, ia->ia_tid, NULL, 0,
	    I2O_PARAM_HBA_SCSI_CTLR_INFO, &param, sizeof(param));
	if (rv != 0) {
		printf("%s: unable to get parameters (0x%04x; %d)\n",
		    sc->sc_dv.dv_xname, I2O_PARAM_HBA_SCSI_CTLR_INFO, rv);
		goto bad;
	}

#ifdef I2OVERBOSE
	printf("%s: %d-bit, max sync rate %dMHz, initiator ID %d\n",
	    sc->sc_dv.dv_xname, param.p.sci.maxdatawidth,
	    (u_int32_t)letoh64(param.p.sci.maxsyncrate) / 1000,
	    letoh32(param.p.sci.initiatorid));
#endif

	sc->sc_link.adapter_softc = sc;
	sc->sc_link.adapter = &iopsp_switch;
	sc->sc_link.adapter_target = letoh32(param.p.sci.initiatorid);
	sc->sc_link.device = &iopsp_dev;
	sc->sc_link.openings = 1;
	sc->sc_link.adapter_buswidth = fcal?
	    IOPSP_MAX_FCAL_TARGET : param.p.sci.maxdatawidth;
	sc->sc_link.luns = IOPSP_MAX_LUN;

#ifdef I2OVERBOSE
	/*
	 * Allocate the target map.  Currently used for informational
	 * purposes only.
	 */
	size = sc->sc_link.adapter_buswidth * sizeof(struct iopsp_target);
	sc->sc_targetmap = malloc(size, M_DEVBUF, M_NOWAIT);
	bzero(sc->sc_targetmap, size);
#endif

 	/* Build the two maps, and attach to scsi. */
	if (iopsp_reconfig(self) != 0) {
		printf("%s: configure failed\n", sc->sc_dv.dv_xname);
		goto bad;
	}

	config_found(&sc->sc_dv, &sc->sc_link, scsiprint);
	return;

 bad:
	iop_initiator_unregister(iop, &sc->sc_ii);
}

/*
 * Scan the LCT to determine which devices we control, and enter them into
 * the maps.
 */
int
iopsp_reconfig(struct device *dv)
{
	struct iopsp_softc *sc = (struct iopsp_softc *)dv;
	struct iop_softc *iop = (struct iop_softc *)sc->sc_dv.dv_parent;
	struct i2o_lct_entry *le;
	struct {
		struct	i2o_param_op_results pr;
		struct	i2o_param_read_results prr;
		struct	i2o_param_scsi_device_info sdi;
	} __attribute__ ((__packed__)) param;
	u_int tid, nent, i, targ, lun, size, s, rv, bptid;
	u_short *tidmap;
#ifdef I2OVERBOSE
	struct iopsp_target *it;
	int syncrate;	
#endif

	/* Anything to do? */
	if (iop->sc_chgind == sc->sc_chgind)
		return (0);

	/*
	 * Allocate memory for the target/LUN -> TID map.  Use zero to
	 * denote absent targets (zero is the TID of the I2O executive,
	 * and we never address that here).
	 */
	size = sc->sc_link.adapter_buswidth * IOPSP_MAX_LUN * sizeof(u_short);
	if (!(tidmap = malloc(size, M_DEVBUF, M_NOWAIT)))
		return (ENOMEM);
	bzero(tidmap, size);

#ifdef I2OVERBOSE
	for (i = 0; i < sc->sc_link.adapter_buswidth; i++)
		sc->sc_targetmap[i].it_flags &= ~IT_PRESENT;
#endif

	/*
	 * A quick hack to handle Intel's stacked bus port arrangement.
	 */
	bptid = sc->sc_ii.ii_tid;
	nent = iop->sc_nlctent;
	for (le = iop->sc_lct->entry; nent != 0; nent--, le++)
		if ((letoh16(le->classid) & 4095) ==
		    I2O_CLASS_BUS_ADAPTER_PORT &&
		    (letoh32(le->usertid) & 4095) == bptid) {
			bptid = letoh16(le->localtid) & 4095;
			break;
		}

	nent = iop->sc_nlctent;
	for (i = 0, le = iop->sc_lct->entry; i < nent; i++, le++) {
		if ((letoh16(le->classid) & I2O_CLASS_MASK) !=
		    I2O_CLASS_SCSI_PERIPHERAL ||
		    ((letoh32(le->usertid) >> 12) & 4095) != bptid)
			continue;
		tid = letoh16(le->localtid) & I2O_LCT_ENTRY_TID_MASK;

		rv = iop_param_op(iop, tid, NULL, 0, I2O_PARAM_SCSI_DEVICE_INFO,
		    &param, sizeof(param));
		if (rv != 0) {
			printf("%s: unable to get parameters (0x%04x; %d)\n",
			    sc->sc_dv.dv_xname, I2O_PARAM_SCSI_DEVICE_INFO,
			    rv);
			continue;
		}
		targ = letoh32(param.sdi.identifier);
		lun = param.sdi.luninfo[1];
#if defined(DIAGNOSTIC) || defined(I2ODEBUG)
		if (targ >= sc->sc_link.adapter_buswidth ||
		    lun >= sc->sc_link.adapter_buswidth) {
			printf("%s: target %d,%d (tid %d): bad target/LUN\n",
			    sc->sc_dv.dv_xname, targ, lun, tid);
			continue;
		}
#endif

#ifdef I2OVERBOSE
		/*
		 * If we've already described this target, and nothing has
		 * changed, then don't describe it again.
		 */
		it = &sc->sc_targetmap[targ];
		it->it_flags |= IT_PRESENT;
		syncrate = (int)((letoh64(param.sdi.negsyncrate) + 500) / 1000);
		if (it->it_width == param.sdi.negdatawidth &&
		    it->it_offset == param.sdi.negoffset &&
		    it->it_syncrate == syncrate)
			continue;

		it->it_width = param.sdi.negdatawidth;
		it->it_offset = param.sdi.negoffset;
		it->it_syncrate = syncrate;

		printf("%s: target %d (tid %d): %d-bit, ", sc->sc_dv.dv_xname,
		    targ, tid, it->it_width);
		if (it->it_syncrate == 0)
			printf("asynchronous\n");
		else
			printf("synchronous at %dMHz, offset 0x%x\n",
			    it->it_syncrate, it->it_offset);
#endif

		/* Ignore the device if it's in use by somebody else. */
		if ((letoh32(le->usertid) & 4095) != I2O_TID_NONE) {
#ifdef I2OVERBOSE
			if (sc->sc_tidmap == NULL ||
			    IOPSP_TIDMAP(sc->sc_tidmap, targ, lun) !=
			    IOPSP_TID_INUSE)
				printf("%s: target %d,%d (tid %d): in use by"
				    " tid %d\n", sc->sc_dv.dv_xname,
				    targ, lun, tid,
				    letoh32(le->usertid) & 4095);
#endif
			IOPSP_TIDMAP(tidmap, targ, lun) = IOPSP_TID_INUSE;
		} else
			IOPSP_TIDMAP(tidmap, targ, lun) = (u_short)tid;
	}

#ifdef I2OVERBOSE
	for (i = 0; i < sc->sc_link.adapter_buswidth; i++)
		if ((sc->sc_targetmap[i].it_flags & IT_PRESENT) == 0)
			sc->sc_targetmap[i].it_width = 0;
#endif

	/* Swap in the new map and return. */
	s = splbio();
	if (sc->sc_tidmap != NULL)
		free(sc->sc_tidmap, M_DEVBUF);
	sc->sc_tidmap = tidmap;
	splx(s);
	sc->sc_chgind = iop->sc_chgind;
	return (0);
}

/*
 * Re-scan the bus; to be called from a higher level (e.g. scsi).
 */
int
iopsp_rescan(struct iopsp_softc *sc)
{
	struct iop_softc *iop;
	struct iop_msg *im;
	struct i2o_hba_bus_scan mf;
	int rv;

	iop = (struct iop_softc *)sc->sc_dv.dv_parent;

	rv = lockmgr(&iop->sc_conflock, LK_EXCLUSIVE, NULL, curproc);
	if (rv != 0) {
#ifdef I2ODEBUG
		printf("iopsp_rescan: unable to acquire lock\n");
#endif
		return (rv);
	}

	im = iop_msg_alloc(iop, &sc->sc_ii, IM_WAIT);

	mf.msgflags = I2O_MSGFLAGS(i2o_hba_bus_scan);
	mf.msgfunc = I2O_MSGFUNC(sc->sc_ii.ii_tid, I2O_HBA_BUS_SCAN);
	mf.msgictx = sc->sc_ii.ii_ictx;
	mf.msgtctx = im->im_tctx;

	rv = iop_msg_post(iop, im, &mf, 5*60*1000);
	iop_msg_free(iop, im);
	if (rv != 0)
		printf("%s: bus rescan failed (error %d)\n",
		    sc->sc_dv.dv_xname, rv);

	if ((rv = iop_lct_get(iop)) == 0)
		rv = iopsp_reconfig(&sc->sc_dv);

	lockmgr(&iop->sc_conflock, LK_RELEASE, NULL, curproc);
	return (rv);
}

void
iopspminphys(bp)
	struct buf *bp;
{
	if (bp->b_bcount > IOP_MAX_XFER)
		bp->b_bcount = IOP_MAX_XFER;
	minphys(bp);
}

/*
 * Start a SCSI command.
 */
int
iopsp_scsi_cmd(xs)
	struct scsi_xfer *xs;
{
	struct scsi_link *link = xs->sc_link;
	struct iopsp_softc *sc = (struct iopsp_softc *)link->adapter_softc;
	struct iop_softc *iop = (struct iop_softc *)sc->sc_dv.dv_parent;
	struct iop_msg *im;
	struct i2o_scsi_scb_exec *mf;
	int error, tid, s;
	u_int32_t mb[IOP_MAX_MSG_SIZE / sizeof(u_int32_t)];

	tid = IOPSP_TIDMAP(sc->sc_tidmap, link->target, link->lun);
	if (tid == IOPSP_TID_ABSENT || tid == IOPSP_TID_INUSE) {
		xs->error = XS_SELTIMEOUT;
		scsi_done(xs);
		return (COMPLETE);
	}

	SC_DEBUG(periph, SDEV_DB2, ("iopsp_scsi_cmd: run_xfer\n"));

	/* Need to reset the target? */
	if ((xs->flags & XS_RESET) != 0) {
		if (iop_simple_cmd(iop, tid, I2O_SCSI_DEVICE_RESET,
		    sc->sc_ii.ii_ictx, 1, 30*1000) != 0) {
#ifdef I2ODEBUG
			printf("%s: reset failed\n",
			    sc->sc_dv.dv_xname);
#endif
			xs->error = XS_DRIVER_STUFFUP;
		} else
			xs->error = XS_NOERROR;

		scsi_done(xs);
		return (COMPLETE);
	}

#if defined(I2ODEBUG) || defined(SCSIDEBUG)
	if (xs->cmdlen > sizeof(mf->cdb))
		panic("%s: CDB too large\n", sc->sc_dv.dv_xname);
#endif

	im = iop_msg_alloc(iop, &sc->sc_ii, IM_POLL_INTR |
	    IM_NOSTATUS | ((xs->flags & SCSI_POLL) != 0 ? IM_POLL : 0));
	im->im_dvcontext = xs;

	mf = (struct i2o_scsi_scb_exec *)mb;
	mf->msgflags = I2O_MSGFLAGS(i2o_scsi_scb_exec);
	mf->msgfunc = I2O_MSGFUNC(tid, I2O_SCSI_SCB_EXEC);
	mf->msgictx = sc->sc_ii.ii_ictx;
	mf->msgtctx = im->im_tctx;
	mf->flags = xs->cmdlen | I2O_SCB_FLAG_ENABLE_DISCONNECT |
	    I2O_SCB_FLAG_SENSE_DATA_IN_MESSAGE;
	mf->datalen = xs->datalen;
	memcpy(mf->cdb, xs->cmd, xs->cmdlen);

#if 0
	switch (xs->xs_tag_type) {
	case MSG_ORDERED_Q_TAG:
		mf->flags |= I2O_SCB_FLAG_ORDERED_QUEUE_TAG;
		break;
	case MSG_SIMPLE_Q_TAG:
		mf->flags |= I2O_SCB_FLAG_SIMPLE_QUEUE_TAG;
		break;
	case MSG_HEAD_OF_Q_TAG:
		mf->flags |= I2O_SCB_FLAG_HEAD_QUEUE_TAG;
		break;
	default:
		break;
	}
#endif

	if (xs->datalen != 0) {
		error = iop_msg_map_bio(iop, im, mb, xs->data,
		    xs->datalen, (xs->flags & SCSI_DATA_OUT) == 0);
		if (error) {
			xs->error = XS_DRIVER_STUFFUP;
			iop_msg_free(iop, im);
			scsi_done(xs);
			return (COMPLETE);
		}
		if ((xs->flags & SCSI_DATA_IN) == 0)
			mf->flags |= I2O_SCB_FLAG_XFER_TO_DEVICE;
		else
			mf->flags |= I2O_SCB_FLAG_XFER_FROM_DEVICE;
	}

	s = splbio();
	sc->sc_curqd++;
	splx(s);

	if (iop_msg_post(iop, im, mb, xs->timeout)) {
		s = splbio();
		sc->sc_curqd--;
		splx(s);
		if (xs->datalen != 0)
			iop_msg_unmap(iop, im);
		iop_msg_free(iop, im);
		xs->error = XS_DRIVER_STUFFUP;
		scsi_done(xs);
		return (COMPLETE);
	}

	return (xs->flags & SCSI_POLL? COMPLETE : SUCCESSFULLY_QUEUED);
}

#ifdef notyet
/*
 * Abort the specified I2O_SCSI_SCB_EXEC message and its associated SCB.
 */
int
iopsp_scsi_abort(struct iopsp_softc *sc, int atid, struct iop_msg *aim)
{
	struct iop_msg *im;
	struct i2o_scsi_scb_abort mf;
	struct iop_softc *iop;
	int rv, s;

	iop = (struct iop_softc *)sc->sc_dv.dv_parent;
	im = iop_msg_alloc(iop, &sc->sc_ii, IM_POLL);

	mf.msgflags = I2O_MSGFLAGS(i2o_scsi_scb_abort);
	mf.msgfunc = I2O_MSGFUNC(atid, I2O_SCSI_SCB_ABORT);
	mf.msgictx = sc->sc_ii.ii_ictx;
	mf.msgtctx = im->im_tctx;
	mf.tctxabort = aim->im_tctx;

	s = splbio();
	rv = iop_msg_post(iop, im, &mf, 30000);
	splx(s);
	iop_msg_free(iop, im);
	return (rv);
}
#endif

/*
 * We have a message which has been processed and replied to by the IOP -
 * deal with it.
 */
void
iopsp_intr(struct device *dv, struct iop_msg *im, void *reply)
{
	struct scsi_xfer *xs;
	struct iopsp_softc *sc;
	struct i2o_scsi_reply *rb;
 	struct iop_softc *iop;
	u_int sl;

	sc = (struct iopsp_softc *)dv;
	xs = (struct scsi_xfer *)im->im_dvcontext;
	iop = (struct iop_softc *)dv->dv_parent;
	rb = reply;

	SC_DEBUG(xs->xs_periph, SDEV_DB2, ("iopsp_intr\n"));

	if ((rb->msgflags & I2O_MSGFLAGS_FAIL) != 0) {
		xs->error = XS_DRIVER_STUFFUP;
		xs->resid = xs->datalen;
	} else {
		if (rb->hbastatus != I2O_SCSI_DSC_SUCCESS) {
			switch (rb->hbastatus) {
			case I2O_SCSI_DSC_ADAPTER_BUSY:
			case I2O_SCSI_DSC_SCSI_BUS_RESET:
			case I2O_SCSI_DSC_BUS_BUSY:
				xs->error = XS_BUSY;
				break;
			case I2O_SCSI_DSC_SELECTION_TIMEOUT:
				xs->error = XS_SELTIMEOUT;
				break;
			case I2O_SCSI_DSC_COMMAND_TIMEOUT:
			case I2O_SCSI_DSC_DEVICE_NOT_PRESENT:
			case I2O_SCSI_DSC_LUN_INVALID:
			case I2O_SCSI_DSC_SCSI_TID_INVALID:
				xs->error = XS_TIMEOUT;
				break;
			default:
				xs->error = XS_DRIVER_STUFFUP;
				break;
			}
			printf("%s: HBA status 0x%02x\n", sc->sc_dv.dv_xname,
			   rb->hbastatus);
		} else if (rb->scsistatus != SCSI_OK) {
			switch (rb->scsistatus) {
			case SCSI_CHECK:
				xs->error = XS_SENSE;
				sl = letoh32(rb->senselen);
				if (sl > sizeof(xs->sense))
					sl = sizeof(xs->sense);
				bcopy(rb->sense, &xs->sense, sl);
				break;
			case SCSI_QUEUE_FULL:
			case SCSI_BUSY:
				xs->error = XS_BUSY;
				break;
			default:
				xs->error = XS_DRIVER_STUFFUP;
				break;
			}
		} else
			xs->error = XS_NOERROR;

		xs->resid = xs->datalen - letoh32(rb->datalen);
		xs->status = rb->scsistatus;
	}

	/* Free the message wrapper and pass the news to scsi. */
	if (xs->datalen != 0)
		iop_msg_unmap(iop, im);
	iop_msg_free(iop, im);

	if (--sc->sc_curqd == sc->sc_link.openings)
		wakeup(&sc->sc_curqd);

	scsi_done(xs);
}

/*
 * The number of openings available to us has changed, so inform scsi.
 */
void
iopsp_adjqparam(struct device *dv, int mpi)
{
	struct iopsp_softc *sc = (struct iopsp_softc *)dv;
	int s;

	s = splbio();
	sc->sc_link.openings = mpi;
	if (mpi < sc->sc_curqd)
		tsleep(&sc->sc_curqd, PWAIT, "iopspdrn", 0);
	splx(s);
}