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sci.c revision 1.9
      1 /*	$NetBSD: sci.c,v 1.9 1994/12/28 09:25:50 chopps Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1994 Michael L. Hitch
      5  * Copyright (c) 1990 The Regents of the University of California.
      6  * All rights reserved.
      7  *
      8  * This code is derived from software contributed to Berkeley by
      9  * Van Jacobson of Lawrence Berkeley Laboratory.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. All advertising materials mentioning features or use of this software
     20  *    must display the following acknowledgement:
     21  *	This product includes software developed by the University of
     22  *	California, Berkeley and its contributors.
     23  * 4. Neither the name of the University nor the names of its contributors
     24  *    may be used to endorse or promote products derived from this software
     25  *    without specific prior written permission.
     26  *
     27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     37  * SUCH DAMAGE.
     38  *
     39  *	@(#)scsi.c	7.5 (Berkeley) 5/4/91
     40  */
     41 
     42 /*
     43  * AMIGA NCR 5380 scsi adaptor driver
     44  */
     45 
     46 #include <sys/param.h>
     47 #include <sys/systm.h>
     48 #include <sys/device.h>
     49 #include <sys/buf.h>
     50 #include <scsi/scsi_all.h>
     51 #include <scsi/scsiconf.h>
     52 #include <vm/vm.h>
     53 #include <vm/vm_kern.h>
     54 #include <vm/vm_page.h>
     55 #include <machine/pmap.h>
     56 #include <machine/cpu.h>
     57 #include <amiga/amiga/device.h>
     58 #include <amiga/amiga/custom.h>
     59 #include <amiga/dev/scireg.h>
     60 #include <amiga/dev/scivar.h>
     61 
     62 /*
     63  * SCSI delays
     64  * In u-seconds, primarily for state changes on the SPC.
     65  */
     66 #define	SCI_CMD_WAIT	50000	/* wait per step of 'immediate' cmds */
     67 #define	SCI_DATA_WAIT	50000	/* wait per data in/out step */
     68 #define	SCI_INIT_WAIT	50000	/* wait per step (both) during init */
     69 
     70 #define	b_cylin		b_resid
     71 
     72 int  sciicmd __P((struct sci_softc *, int, void *, int, void *, int,u_char));
     73 int  scigo __P((struct sci_softc *, struct scsi_xfer *));
     74 int  scigetsense __P((struct sci_softc *, struct scsi_xfer *));
     75 int  sciselectbus __P((struct sci_softc *, u_char, u_char));
     76 void sciabort __P((struct sci_softc *, char *));
     77 void scierror __P((struct sci_softc *, u_char));
     78 void scireset __P((struct sci_softc *));
     79 void scisetdelay __P((int));
     80 void sci_scsidone __P((struct sci_softc *, int));
     81 void sci_donextcmd __P((struct sci_softc *));
     82 
     83 int sci_cmd_wait = SCI_CMD_WAIT;
     84 int sci_data_wait = SCI_DATA_WAIT;
     85 int sci_init_wait = SCI_INIT_WAIT;
     86 
     87 int sci_no_dma = 0;
     88 
     89 #ifdef DEBUG
     90 #define QPRINTF(a) if (sci_debug > 1) printf a
     91 int	sci_debug = 0;
     92 #else
     93 #define QPRINTF
     94 #endif
     95 
     96 /*
     97  * default minphys routine for sci based controllers
     98  */
     99 void
    100 sci_minphys(bp)
    101 	struct buf *bp;
    102 {
    103 	/*
    104 	 * no max transfer at this level
    105 	 */
    106 }
    107 
    108 /*
    109  * must be used
    110  */
    111 u_int
    112 sci_adinfo()
    113 {
    114 	/*
    115 	 * one request at a time please
    116 	 */
    117 	return(1);
    118 }
    119 
    120 /*
    121  * used by specific sci controller
    122  *
    123  * it appears that the higher level code does nothing with LUN's
    124  * so I will too.  I could plug it in, however so could they
    125  * in scsi_scsi_cmd().
    126  */
    127 int
    128 sci_scsicmd(xs)
    129 	struct scsi_xfer *xs;
    130 {
    131 	struct sci_pending *pendp;
    132 	struct sci_softc *dev;
    133 	struct scsi_link *slp;
    134 	int flags, s;
    135 
    136 	slp = xs->sc_link;
    137 	dev = slp->adapter_softc;
    138 	flags = xs->flags;
    139 
    140 	if (flags & SCSI_DATA_UIO)
    141 		panic("sci: scsi data uio requested");
    142 
    143 	if (dev->sc_xs && flags & SCSI_NOMASK)
    144 		panic("sci_scsicmd: busy");
    145 
    146 	s = splbio();
    147 	pendp = &dev->sc_xsstore[slp->target][slp->lun];
    148 	if (pendp->xs) {
    149 		splx(s);
    150 		return(TRY_AGAIN_LATER);
    151 	}
    152 
    153 	if (dev->sc_xs) {
    154 		pendp->xs = xs;
    155 		TAILQ_INSERT_TAIL(&dev->sc_xslist, pendp, link);
    156 		splx(s);
    157 		return(SUCCESSFULLY_QUEUED);
    158 	}
    159 	pendp->xs = NULL;
    160 	dev->sc_xs = xs;
    161 	splx(s);
    162 
    163 	/*
    164 	 * nothing is pending do it now.
    165 	 */
    166 	sci_donextcmd(dev);
    167 
    168 	if (flags & SCSI_NOMASK)
    169 		return(COMPLETE);
    170 	return(SUCCESSFULLY_QUEUED);
    171 }
    172 
    173 /*
    174  * entered with dev->sc_xs pointing to the next xfer to perform
    175  */
    176 void
    177 sci_donextcmd(dev)
    178 	struct sci_softc *dev;
    179 {
    180 	struct scsi_xfer *xs;
    181 	struct scsi_link *slp;
    182 	int flags, phase, stat;
    183 
    184 	xs = dev->sc_xs;
    185 	slp = xs->sc_link;
    186 	flags = xs->flags;
    187 
    188 	if (flags & SCSI_DATA_IN)
    189 		phase = DATA_IN_PHASE;
    190 	else if (flags & SCSI_DATA_OUT)
    191 		phase = DATA_OUT_PHASE;
    192 	else
    193 		phase = STATUS_PHASE;
    194 
    195 	if (flags & SCSI_RESET)
    196 		scireset(dev);
    197 
    198 	dev->sc_stat[0] = -1;
    199 	xs->cmd->bytes[0] |= slp->lun << 5;
    200 	if (phase == STATUS_PHASE || flags & SCSI_NOMASK)
    201 		stat = sciicmd(dev, slp->target, xs->cmd, xs->cmdlen,
    202 		    xs->data, xs->datalen, phase);
    203 	else if (scigo(dev, xs) == 0)
    204 		return;
    205 	else
    206 		stat = dev->sc_stat[0];
    207 
    208 	sci_scsidone(dev, stat);
    209 }
    210 
    211 void
    212 sci_scsidone(dev, stat)
    213 	struct sci_softc *dev;
    214 	int stat;
    215 {
    216 	struct sci_pending *pendp;
    217 	struct scsi_xfer *xs;
    218 	int s, donext;
    219 
    220 	xs = dev->sc_xs;
    221 #ifdef DIAGNOSTIC
    222 	if (xs == NULL)
    223 		panic("sci_scsidone");
    224 #endif
    225 	/*
    226 	 * is this right?
    227 	 */
    228 	xs->status = stat;
    229 
    230 	if (stat == 0 || xs->flags & SCSI_ERR_OK)
    231 		xs->resid = 0;
    232 	else {
    233 		switch(stat) {
    234 		case SCSI_CHECK:
    235 			if (stat = scigetsense(dev, xs))
    236 				goto bad_sense;
    237 			xs->error = XS_SENSE;
    238 			break;
    239 		case SCSI_BUSY:
    240 			xs->error = XS_BUSY;
    241 			break;
    242 		bad_sense:
    243 		default:
    244 			xs->error = XS_DRIVER_STUFFUP;
    245 			QPRINTF(("sci_scsicmd() bad %x\n", stat));
    246 			break;
    247 		}
    248 	}
    249 	xs->flags |= ITSDONE;
    250 
    251 	/*
    252 	 * grab next command before scsi_done()
    253 	 * this way no single device can hog scsi resources.
    254 	 */
    255 	s = splbio();
    256 	pendp = dev->sc_xslist.tqh_first;
    257 	if (pendp == NULL) {
    258 		donext = 0;
    259 		dev->sc_xs = NULL;
    260 	} else {
    261 		donext = 1;
    262 		TAILQ_REMOVE(&dev->sc_xslist, pendp, link);
    263 		dev->sc_xs = pendp->xs;
    264 		pendp->xs = NULL;
    265 	}
    266 	splx(s);
    267 	scsi_done(xs);
    268 
    269 	if (donext)
    270 		sci_donextcmd(dev);
    271 }
    272 
    273 int
    274 scigetsense(dev, xs)
    275 	struct sci_softc *dev;
    276 	struct scsi_xfer *xs;
    277 {
    278 	struct scsi_sense rqs;
    279 	struct scsi_link *slp;
    280 	int stat;
    281 
    282 	slp = xs->sc_link;
    283 
    284 	rqs.op_code = REQUEST_SENSE;
    285 	rqs.byte2 = slp->lun << 5;
    286 #ifdef not_yet
    287 	rqs.length = xs->req_sense_length ? xs->req_sense_length :
    288 	    sizeof(xs->sense);
    289 #else
    290 	rqs.length = sizeof(xs->sense);
    291 #endif
    292 
    293 	rqs.unused[0] = rqs.unused[1] = rqs.control = 0;
    294 
    295 	return(sciicmd(dev, slp->target, &rqs, sizeof(rqs), &xs->sense,
    296 	    rqs.length, DATA_IN_PHASE));
    297 }
    298 
    299 void
    300 sciabort(dev, where)
    301 	struct sci_softc *dev;
    302 	char *where;
    303 {
    304 	printf ("%s: abort %s: csr = 0x%02x, bus = 0x%02x\n",
    305 	  dev->sc_dev.dv_xname, where, *dev->sci_csr, *dev->sci_bus_csr);
    306 
    307 	if (dev->sc_flags & SCI_SELECTED) {
    308 
    309 		/* lets just hope it worked.. */
    310 		dev->sc_flags &= ~SCI_SELECTED;
    311 		/* XXX */
    312 		scireset (dev);
    313 	}
    314 }
    315 
    316 /*
    317  * XXX Set/reset long delays.
    318  *
    319  * if delay == 0, reset default delays
    320  * if delay < 0,  set both delays to default long initialization values
    321  * if delay > 0,  set both delays to this value
    322  *
    323  * Used when a devices is expected to respond slowly (e.g. during
    324  * initialization).
    325  */
    326 void
    327 scisetdelay(del)
    328 	int del;
    329 {
    330 	static int saved_cmd_wait, saved_data_wait;
    331 
    332 	if (del) {
    333 		saved_cmd_wait = sci_cmd_wait;
    334 		saved_data_wait = sci_data_wait;
    335 		if (del > 0)
    336 			sci_cmd_wait = sci_data_wait = del;
    337 		else
    338 			sci_cmd_wait = sci_data_wait = sci_init_wait;
    339 	} else {
    340 		sci_cmd_wait = saved_cmd_wait;
    341 		sci_data_wait = saved_data_wait;
    342 	}
    343 }
    344 
    345 void
    346 scireset(dev)
    347 	struct sci_softc *dev;
    348 {
    349 	u_int i, s;
    350 	u_char my_id, csr;
    351 
    352 	dev->sc_flags &= ~SCI_SELECTED;
    353 	if (dev->sc_flags & SCI_ALIVE)
    354 		sciabort(dev, "reset");
    355 
    356 	printf("%s: ", dev->sc_dev.dv_xname);
    357 
    358 	s = splbio();
    359 	/* preserve our ID for now */
    360 	my_id = 7;
    361 
    362 	/*
    363 	 * Reset the chip
    364 	 */
    365 	*dev->sci_icmd = SCI_ICMD_TEST;
    366 	*dev->sci_icmd = SCI_ICMD_TEST | SCI_ICMD_RST;
    367 	delay (25);
    368 	*dev->sci_icmd = 0;
    369 
    370 	/*
    371 	 * Set up various chip parameters
    372 	 */
    373 	*dev->sci_icmd = 0;
    374 	*dev->sci_tcmd = 0;
    375 	*dev->sci_sel_enb = 0;
    376 
    377 	/* anything else was zeroed by reset */
    378 
    379 	splx (s);
    380 
    381 	printf("sci id %d\n", my_id);
    382 	dev->sc_flags |= SCI_ALIVE;
    383 }
    384 
    385 void
    386 scierror(dev, csr)
    387 	struct sci_softc *dev;
    388 	u_char csr;
    389 {
    390 	struct scsi_xfer *xs;
    391 
    392 	xs = dev->sc_xs;
    393 
    394 #ifdef DIAGNOSTIC
    395 	if (xs == NULL)
    396 		panic("scierror");
    397 #endif
    398 	if (xs->flags & SCSI_SILENT)
    399 		return;
    400 
    401 	printf("%s: ", dev->sc_dev.dv_xname);
    402 	printf("csr == 0x%02i\n", csr);	/* XXX */
    403 }
    404 
    405 /*
    406  * select the bus, return when selected or error.
    407  */
    408 int
    409 sciselectbus(dev, target, our_addr)
    410         struct sci_softc *dev;
    411 	u_char target, our_addr;
    412 {
    413 	register int timeo = 2500;
    414 
    415 	QPRINTF (("sciselectbus %d\n", target));
    416 
    417 	/* if we're already selected, return */
    418 	if (dev->sc_flags & SCI_SELECTED)	/* XXXX */
    419 		return 1;
    420 
    421 	if ((*dev->sci_bus_csr & (SCI_BUS_BSY|SCI_BUS_SEL)) &&
    422 	    (*dev->sci_bus_csr & (SCI_BUS_BSY|SCI_BUS_SEL)) &&
    423 	    (*dev->sci_bus_csr & (SCI_BUS_BSY|SCI_BUS_SEL)))
    424 		return 1;
    425 
    426 	*dev->sci_tcmd = 0;
    427 	*dev->sci_odata = 0x80 + (1 << target);
    428 	*dev->sci_icmd = SCI_ICMD_DATA|SCI_ICMD_SEL;
    429 	while ((*dev->sci_bus_csr & SCI_BUS_BSY) == 0) {
    430 		if (--timeo > 0) {
    431 			delay(100);
    432 		} else {
    433 			break;
    434 		}
    435 	}
    436 	if (timeo) {
    437 		*dev->sci_icmd = 0;
    438 		dev->sc_flags |= SCI_SELECTED;
    439 		return (0);
    440 	}
    441 	*dev->sci_icmd = 0;
    442 	return (1);
    443 }
    444 
    445 int
    446 sci_ixfer_out(dev, len, buf, phase)
    447 	register struct sci_softc *dev;
    448 	int len;
    449 	register u_char *buf;
    450 	int phase;
    451 {
    452 	register int wait = sci_data_wait;
    453 	u_char csr;
    454 
    455 	QPRINTF(("sci_ixfer_out {%d} %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
    456 	  len, buf[0], buf[1], buf[2], buf[3], buf[4], buf[5],
    457 	  buf[6], buf[7], buf[8], buf[9]));
    458 
    459 	*dev->sci_tcmd = phase;
    460 	*dev->sci_icmd = SCI_ICMD_DATA;
    461 	for (;len > 0; len--) {
    462 		csr = *dev->sci_bus_csr;
    463 		while (!(csr & SCI_BUS_REQ)) {
    464 			if ((csr & SCI_BUS_BSY) == 0 || --wait < 0) {
    465 #ifdef DEBUG
    466 				if (sci_debug)
    467 					printf("sci_ixfer_out fail: l%d i%x w%d\n",
    468 					  len, csr, wait);
    469 #endif
    470 				return (len);
    471 			}
    472 			delay(1);
    473 			csr = *dev->sci_bus_csr;
    474 		}
    475 
    476 		if (!(*dev->sci_csr & SCI_CSR_PHASE_MATCH))
    477 			break;
    478 		*dev->sci_odata = *buf;
    479 		*dev->sci_icmd = SCI_ICMD_DATA|SCI_ICMD_ACK;
    480 		buf++;
    481 		while (*dev->sci_bus_csr & SCI_BUS_REQ);
    482 		*dev->sci_icmd = SCI_ICMD_DATA;
    483 	}
    484 
    485 	QPRINTF(("sci_ixfer_out done\n"));
    486 	return (0);
    487 }
    488 
    489 void
    490 sci_ixfer_in(dev, len, buf, phase)
    491 	struct sci_softc *dev;
    492 	int len;
    493 	register u_char *buf;
    494 	int phase;
    495 {
    496 	int wait = sci_data_wait;
    497 	u_char *obp = buf;
    498 	u_char csr;
    499 	volatile register u_char *sci_bus_csr = dev->sci_bus_csr;
    500 	volatile register u_char *sci_data = dev->sci_data;
    501 	volatile register u_char *sci_icmd = dev->sci_icmd;
    502 
    503 	csr = *sci_bus_csr;
    504 
    505 	QPRINTF(("sci_ixfer_in %d, csr=%02x\n", len, csr));
    506 
    507 	*dev->sci_tcmd = phase;
    508 	*sci_icmd = 0;
    509 	for (;len > 0; len--) {
    510 		csr = *sci_bus_csr;
    511 		while (!(csr & SCI_BUS_REQ)) {
    512 			if (!(csr & SCI_BUS_BSY) || --wait < 0) {
    513 #ifdef DEBUG
    514 				if (sci_debug)
    515 					printf("sci_ixfer_in fail: l%d i%x w%d\n",
    516 					len, csr, wait);
    517 #endif
    518 				return;
    519 			}
    520 
    521 			delay(1);
    522 			csr = *sci_bus_csr;
    523 		}
    524 
    525 		if (!(*dev->sci_csr & SCI_CSR_PHASE_MATCH))
    526 			break;
    527 		*buf = *sci_data;
    528 		*sci_icmd = SCI_ICMD_ACK;
    529 		buf++;
    530 		while (*sci_bus_csr & SCI_BUS_REQ);
    531 		*sci_icmd = 0;
    532 	}
    533 
    534 	QPRINTF(("sci_ixfer_in {%d} %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
    535 	  len, obp[0], obp[1], obp[2], obp[3], obp[4], obp[5],
    536 	  obp[6], obp[7], obp[8], obp[9]));
    537 }
    538 
    539 /*
    540  * SCSI 'immediate' command:  issue a command to some SCSI device
    541  * and get back an 'immediate' response (i.e., do programmed xfer
    542  * to get the response data).  'cbuf' is a buffer containing a scsi
    543  * command of length clen bytes.  'buf' is a buffer of length 'len'
    544  * bytes for data.  The transfer direction is determined by the device
    545  * (i.e., by the scsi bus data xfer phase).  If 'len' is zero, the
    546  * command must supply no data.  'xferphase' is the bus phase the
    547  * caller expects to happen after the command is issued.  It should
    548  * be one of DATA_IN_PHASE, DATA_OUT_PHASE or STATUS_PHASE.
    549  */
    550 int
    551 sciicmd(dev, target, cbuf, clen, buf, len, xferphase)
    552 	struct sci_softc *dev;
    553 	void *cbuf, *buf;
    554 	int clen, len;
    555 	u_char xferphase;
    556 {
    557 	u_char phase, csr, asr;
    558 	register int wait;
    559 
    560 	/* select the SCSI bus (it's an error if bus isn't free) */
    561 	if (sciselectbus (dev, target, dev->sc_scsi_addr))
    562 		return -1;
    563 	/*
    564 	 * Wait for a phase change (or error) then let the device
    565 	 * sequence us through the various SCSI phases.
    566 	 */
    567 	dev->sc_stat[0] = 0xff;
    568 	dev->sc_msg[0] = 0xff;
    569 	phase = CMD_PHASE;
    570 	while (1) {
    571 		wait = sci_cmd_wait;
    572 
    573 		while ((*dev->sci_bus_csr & (SCI_BUS_REQ|SCI_BUS_BSY)) == SCI_BUS_BSY);
    574 
    575 		QPRINTF((">CSR:%02x<", *dev->sci_bus_csr));
    576 		if ((*dev->sci_bus_csr & SCI_BUS_REQ) == 0) {
    577 			return -1;
    578 		}
    579 		phase = SCI_PHASE(*dev->sci_bus_csr);
    580 
    581 		switch (phase) {
    582 		case CMD_PHASE:
    583 			if (sci_ixfer_out (dev, clen, cbuf, phase))
    584 				goto abort;
    585 			phase = xferphase;
    586 			break;
    587 
    588 		case DATA_IN_PHASE:
    589 			if (len <= 0)
    590 				goto abort;
    591 			wait = sci_data_wait;
    592 			sci_ixfer_in (dev, len, buf, phase);
    593 			phase = STATUS_PHASE;
    594 			break;
    595 
    596 		case DATA_OUT_PHASE:
    597 			if (len <= 0)
    598 				goto abort;
    599 			wait = sci_data_wait;
    600 			if (sci_ixfer_out (dev, len, buf, phase))
    601 				goto abort;
    602 			phase = STATUS_PHASE;
    603 			break;
    604 
    605 		case MESG_IN_PHASE:
    606 			dev->sc_msg[0] = 0xff;
    607 			sci_ixfer_in (dev, 1, dev->sc_msg,phase);
    608 			dev->sc_flags &= ~SCI_SELECTED;
    609 			while (*dev->sci_bus_csr & SCI_BUS_BSY);
    610 			goto out;
    611 			break;
    612 
    613 		case MESG_OUT_PHASE:
    614 			phase = STATUS_PHASE;
    615 			break;
    616 
    617 		case STATUS_PHASE:
    618 			sci_ixfer_in (dev, 1, dev->sc_stat, phase);
    619 			phase = MESG_IN_PHASE;
    620 			break;
    621 
    622 		case BUS_FREE_PHASE:
    623 			goto out;
    624 
    625 		default:
    626 		printf("sci: unexpected phase %d in icmd from %d\n",
    627 		  phase, target);
    628 		goto abort;
    629 		}
    630 #if 0
    631 		if (wait <= 0)
    632 			goto abort;
    633 #endif
    634 	}
    635 
    636 abort:
    637 	sciabort(dev, "icmd");
    638 out:
    639 	QPRINTF(("=STS:%02x=", dev->sc_stat[0]));
    640 	return (dev->sc_stat[0]);
    641 }
    642 
    643 int
    644 scigo(dev, xs)
    645 	struct sci_softc *dev;
    646 	struct scsi_xfer *xs;
    647 {
    648 	int i, count, target;
    649 	u_char phase, csr, asr, cmd, *addr;
    650 	int wait;
    651 
    652 	target = xs->sc_link->target;
    653 	count = xs->datalen;
    654 	addr = xs->data;
    655 
    656 	if (sci_no_dma)	{
    657 		sciicmd (dev, target, (u_char *) xs->cmd, xs->cmdlen,
    658 		  addr, count,
    659 		  xs->flags & SCSI_DATA_IN ? DATA_IN_PHASE : DATA_OUT_PHASE);
    660 
    661 		return (1);
    662 	}
    663 
    664 	/* select the SCSI bus (it's an error if bus isn't free) */
    665 	if (sciselectbus (dev, target, dev->sc_scsi_addr))
    666 		return -1;
    667 	/*
    668 	 * Wait for a phase change (or error) then let the device
    669 	 * sequence us through the various SCSI phases.
    670 	 */
    671 	dev->sc_stat[0] = 0xff;
    672 	dev->sc_msg[0] = 0xff;
    673 	phase = CMD_PHASE;
    674 	while (1) {
    675 		while ((*dev->sci_bus_csr & (SCI_BUS_REQ|SCI_BUS_BSY)) ==
    676 		  SCI_BUS_BSY);
    677 
    678 		QPRINTF((">CSR:%02x<", *dev->sci_bus_csr));
    679 		if ((*dev->sci_bus_csr & SCI_BUS_REQ) == 0) {
    680 			goto abort;
    681 		}
    682 		phase = SCI_PHASE(*dev->sci_bus_csr);
    683 
    684 		switch (phase) {
    685 		case CMD_PHASE:
    686 			if (sci_ixfer_out (dev, xs->cmdlen, xs->cmd, phase))
    687 				goto abort;
    688 			phase = xs->flags & SCSI_DATA_IN ? DATA_IN_PHASE : DATA_OUT_PHASE;
    689 			break;
    690 
    691 		case DATA_IN_PHASE:
    692 			if (count <= 0)
    693 				goto abort;
    694 			/* XXX use psuedo DMA if available */
    695 			if (count >= 128 && dev->dma_xfer_in)
    696 				(*dev->dma_xfer_in)(dev, count, addr, phase);
    697 			else
    698 				sci_ixfer_in (dev, count, addr, phase);
    699 			phase = STATUS_PHASE;
    700 			break;
    701 
    702 		case DATA_OUT_PHASE:
    703 			if (count <= 0)
    704 				goto abort;
    705 			/* XXX use psuedo DMA if available */
    706 			if (count >= 128 && dev->dma_xfer_out)
    707 				(*dev->dma_xfer_out)(dev, count, addr, phase);
    708 			else
    709 				if (sci_ixfer_out (dev, count, addr, phase))
    710 					goto abort;
    711 			phase = STATUS_PHASE;
    712 			break;
    713 
    714 		case MESG_IN_PHASE:
    715 			dev->sc_msg[0] = 0xff;
    716 			sci_ixfer_in (dev, 1, dev->sc_msg,phase);
    717 			dev->sc_flags &= ~SCI_SELECTED;
    718 			while (*dev->sci_bus_csr & SCI_BUS_BSY);
    719 			goto out;
    720 			break;
    721 
    722 		case MESG_OUT_PHASE:
    723 			phase = STATUS_PHASE;
    724 			break;
    725 
    726 		case STATUS_PHASE:
    727 			sci_ixfer_in (dev, 1, dev->sc_stat, phase);
    728 			phase = MESG_IN_PHASE;
    729 			break;
    730 
    731 		case BUS_FREE_PHASE:
    732 			goto out;
    733 
    734 		default:
    735 		printf("sci: unexpected phase %d in icmd from %d\n",
    736 		  phase, target);
    737 		goto abort;
    738 		}
    739 	}
    740 
    741 abort:
    742 	sciabort(dev, "go");
    743 out:
    744 	QPRINTF(("=STS:%02x=", dev->sc_stat[0]));
    745 	return (1);
    746 }
    747