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sci.c revision 1.19
      1 /*	$NetBSD: sci.c,v 1.19 1996/10/13 03:07:31 christos 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/disklabel.h>
     50 #include <sys/dkstat.h>
     51 #include <sys/buf.h>
     52 #include <scsi/scsi_all.h>
     53 #include <scsi/scsiconf.h>
     54 #include <vm/vm.h>
     55 #include <vm/vm_kern.h>
     56 #include <vm/vm_page.h>
     57 #include <machine/pmap.h>
     58 #include <machine/cpu.h>
     59 #include <amiga/amiga/device.h>
     60 #include <amiga/amiga/custom.h>
     61 #include <amiga/amiga/isr.h>
     62 #include <amiga/dev/scireg.h>
     63 #include <amiga/dev/scivar.h>
     64 
     65 /*
     66  * SCSI delays
     67  * In u-seconds, primarily for state changes on the SPC.
     68  */
     69 #define	SCI_CMD_WAIT	50000	/* wait per step of 'immediate' cmds */
     70 #define	SCI_DATA_WAIT	50000	/* wait per data in/out step */
     71 #define	SCI_INIT_WAIT	50000	/* wait per step (both) during init */
     72 
     73 #define	b_cylin		b_resid
     74 
     75 int  sciicmd __P((struct sci_softc *, int, void *, int, void *, int,u_char));
     76 int  scigo __P((struct sci_softc *, struct scsi_xfer *));
     77 int  scigetsense __P((struct sci_softc *, struct scsi_xfer *));
     78 int  sciselectbus __P((struct sci_softc *, u_char, u_char));
     79 void sciabort __P((struct sci_softc *, char *));
     80 void scierror __P((struct sci_softc *, u_char));
     81 void scisetdelay __P((int));
     82 void sci_scsidone __P((struct sci_softc *, int));
     83 void sci_donextcmd __P((struct sci_softc *));
     84 int  sci_ixfer_out __P((struct sci_softc *, int, register u_char *, int));
     85 void sci_ixfer_in __P((struct sci_softc *, int, register u_char *, int));
     86 
     87 int sci_cmd_wait = SCI_CMD_WAIT;
     88 int sci_data_wait = SCI_DATA_WAIT;
     89 int sci_init_wait = SCI_INIT_WAIT;
     90 
     91 int sci_no_dma = 0;
     92 
     93 #ifdef DEBUG
     94 #define QPRINTF(a) if (sci_debug > 1) printf a
     95 int	sci_debug = 0;
     96 #else
     97 #define QPRINTF(a)
     98 #endif
     99 
    100 /*
    101  * default minphys routine for sci based controllers
    102  */
    103 void
    104 sci_minphys(bp)
    105 	struct buf *bp;
    106 {
    107 
    108 	/*
    109 	 * No max transfer at this level.
    110 	 */
    111 	minphys(bp);
    112 }
    113 
    114 /*
    115  * used by specific sci controller
    116  *
    117  * it appears that the higher level code does nothing with LUN's
    118  * so I will too.  I could plug it in, however so could they
    119  * in scsi_scsi_cmd().
    120  */
    121 int
    122 sci_scsicmd(xs)
    123 	struct scsi_xfer *xs;
    124 {
    125 	struct sci_pending *pendp;
    126 	struct sci_softc *dev;
    127 	struct scsi_link *slp;
    128 	int flags, s;
    129 
    130 	slp = xs->sc_link;
    131 	dev = slp->adapter_softc;
    132 	flags = xs->flags;
    133 
    134 	if (flags & SCSI_DATA_UIO)
    135 		panic("sci: scsi data uio requested");
    136 
    137 	if (dev->sc_xs && flags & SCSI_POLL)
    138 		panic("sci_scsicmd: busy");
    139 
    140 	s = splbio();
    141 	pendp = &dev->sc_xsstore[slp->target][slp->lun];
    142 	if (pendp->xs) {
    143 		splx(s);
    144 		return(TRY_AGAIN_LATER);
    145 	}
    146 
    147 	if (dev->sc_xs) {
    148 		pendp->xs = xs;
    149 		TAILQ_INSERT_TAIL(&dev->sc_xslist, pendp, link);
    150 		splx(s);
    151 		return(SUCCESSFULLY_QUEUED);
    152 	}
    153 	pendp->xs = NULL;
    154 	dev->sc_xs = xs;
    155 	splx(s);
    156 
    157 	/*
    158 	 * nothing is pending do it now.
    159 	 */
    160 	sci_donextcmd(dev);
    161 
    162 	if (flags & SCSI_POLL)
    163 		return(COMPLETE);
    164 	return(SUCCESSFULLY_QUEUED);
    165 }
    166 
    167 /*
    168  * entered with dev->sc_xs pointing to the next xfer to perform
    169  */
    170 void
    171 sci_donextcmd(dev)
    172 	struct sci_softc *dev;
    173 {
    174 	struct scsi_xfer *xs;
    175 	struct scsi_link *slp;
    176 	int flags, phase, stat;
    177 
    178 	xs = dev->sc_xs;
    179 	slp = xs->sc_link;
    180 	flags = xs->flags;
    181 
    182 	if (flags & SCSI_DATA_IN)
    183 		phase = DATA_IN_PHASE;
    184 	else if (flags & SCSI_DATA_OUT)
    185 		phase = DATA_OUT_PHASE;
    186 	else
    187 		phase = STATUS_PHASE;
    188 
    189 	if (flags & SCSI_RESET)
    190 		scireset(dev);
    191 
    192 	dev->sc_stat[0] = -1;
    193 	xs->cmd->bytes[0] |= slp->lun << 5;
    194 	if (phase == STATUS_PHASE || flags & SCSI_POLL)
    195 		stat = sciicmd(dev, slp->target, xs->cmd, xs->cmdlen,
    196 		    xs->data, xs->datalen, phase);
    197 	else if (scigo(dev, xs) == 0)
    198 		return;
    199 	else
    200 		stat = dev->sc_stat[0];
    201 
    202 	sci_scsidone(dev, stat);
    203 }
    204 
    205 void
    206 sci_scsidone(dev, stat)
    207 	struct sci_softc *dev;
    208 	int stat;
    209 {
    210 	struct sci_pending *pendp;
    211 	struct scsi_xfer *xs;
    212 	int s, donext;
    213 
    214 	xs = dev->sc_xs;
    215 #ifdef DIAGNOSTIC
    216 	if (xs == NULL)
    217 		panic("sci_scsidone");
    218 #endif
    219 	/*
    220 	 * is this right?
    221 	 */
    222 	xs->status = stat;
    223 
    224 	if (stat == 0)
    225 		xs->resid = 0;
    226 	else {
    227 		switch(stat) {
    228 		case SCSI_CHECK:
    229 			stat = scigetsense(dev, xs);
    230 			if (stat != 0)
    231 				goto bad_sense;
    232 			xs->error = XS_SENSE;
    233 			break;
    234 		case SCSI_BUSY:
    235 			xs->error = XS_BUSY;
    236 			break;
    237 		bad_sense:
    238 		default:
    239 			xs->error = XS_DRIVER_STUFFUP;
    240 			QPRINTF(("sci_scsicmd() bad %x\n", stat));
    241 			break;
    242 		}
    243 	}
    244 	xs->flags |= ITSDONE;
    245 
    246 	/*
    247 	 * grab next command before scsi_done()
    248 	 * this way no single device can hog scsi resources.
    249 	 */
    250 	s = splbio();
    251 	pendp = dev->sc_xslist.tqh_first;
    252 	if (pendp == NULL) {
    253 		donext = 0;
    254 		dev->sc_xs = NULL;
    255 	} else {
    256 		donext = 1;
    257 		TAILQ_REMOVE(&dev->sc_xslist, pendp, link);
    258 		dev->sc_xs = pendp->xs;
    259 		pendp->xs = NULL;
    260 	}
    261 	splx(s);
    262 	scsi_done(xs);
    263 
    264 	if (donext)
    265 		sci_donextcmd(dev);
    266 }
    267 
    268 int
    269 scigetsense(dev, xs)
    270 	struct sci_softc *dev;
    271 	struct scsi_xfer *xs;
    272 {
    273 	struct scsi_sense rqs;
    274 	struct scsi_link *slp;
    275 
    276 	slp = xs->sc_link;
    277 
    278 	rqs.opcode = REQUEST_SENSE;
    279 	rqs.byte2 = slp->lun << 5;
    280 #ifdef not_yet
    281 	rqs.length = xs->req_sense_length ? xs->req_sense_length :
    282 	    sizeof(xs->sense);
    283 #else
    284 	rqs.length = sizeof(xs->sense);
    285 #endif
    286 
    287 	rqs.unused[0] = rqs.unused[1] = rqs.control = 0;
    288 
    289 	return(sciicmd(dev, slp->target, &rqs, sizeof(rqs), &xs->sense,
    290 	    rqs.length, DATA_IN_PHASE));
    291 }
    292 
    293 void
    294 sciabort(dev, where)
    295 	struct sci_softc *dev;
    296 	char *where;
    297 {
    298 	printf ("%s: abort %s: csr = 0x%02x, bus = 0x%02x\n",
    299 	  dev->sc_dev.dv_xname, where, *dev->sci_csr, *dev->sci_bus_csr);
    300 
    301 	if (dev->sc_flags & SCI_SELECTED) {
    302 
    303 		/* lets just hope it worked.. */
    304 		dev->sc_flags &= ~SCI_SELECTED;
    305 		/* XXX */
    306 		scireset (dev);
    307 	}
    308 }
    309 
    310 /*
    311  * XXX Set/reset long delays.
    312  *
    313  * if delay == 0, reset default delays
    314  * if delay < 0,  set both delays to default long initialization values
    315  * if delay > 0,  set both delays to this value
    316  *
    317  * Used when a devices is expected to respond slowly (e.g. during
    318  * initialization).
    319  */
    320 void
    321 scisetdelay(del)
    322 	int del;
    323 {
    324 	static int saved_cmd_wait, saved_data_wait;
    325 
    326 	if (del) {
    327 		saved_cmd_wait = sci_cmd_wait;
    328 		saved_data_wait = sci_data_wait;
    329 		if (del > 0)
    330 			sci_cmd_wait = sci_data_wait = del;
    331 		else
    332 			sci_cmd_wait = sci_data_wait = sci_init_wait;
    333 	} else {
    334 		sci_cmd_wait = saved_cmd_wait;
    335 		sci_data_wait = saved_data_wait;
    336 	}
    337 }
    338 
    339 void
    340 scireset(dev)
    341 	struct sci_softc *dev;
    342 {
    343 	u_int s;
    344 	u_char my_id;
    345 
    346 	dev->sc_flags &= ~SCI_SELECTED;
    347 	if (dev->sc_flags & SCI_ALIVE)
    348 		sciabort(dev, "reset");
    349 
    350 	printf("%s: ", dev->sc_dev.dv_xname);
    351 
    352 	s = splbio();
    353 	/* preserve our ID for now */
    354 	my_id = 7;
    355 
    356 	/*
    357 	 * Reset the chip
    358 	 */
    359 	*dev->sci_icmd = SCI_ICMD_TEST;
    360 	*dev->sci_icmd = SCI_ICMD_TEST | SCI_ICMD_RST;
    361 	delay (25);
    362 	*dev->sci_icmd = 0;
    363 
    364 	/*
    365 	 * Set up various chip parameters
    366 	 */
    367 	*dev->sci_icmd = 0;
    368 	*dev->sci_tcmd = 0;
    369 	*dev->sci_sel_enb = 0;
    370 
    371 	/* anything else was zeroed by reset */
    372 
    373 	splx (s);
    374 
    375 	printf("sci id %d\n", my_id);
    376 	dev->sc_flags |= SCI_ALIVE;
    377 }
    378 
    379 void
    380 scierror(dev, csr)
    381 	struct sci_softc *dev;
    382 	u_char csr;
    383 {
    384 	struct scsi_xfer *xs;
    385 
    386 	xs = dev->sc_xs;
    387 
    388 #ifdef DIAGNOSTIC
    389 	if (xs == NULL)
    390 		panic("scierror");
    391 #endif
    392 	if (xs->flags & SCSI_SILENT)
    393 		return;
    394 
    395 	printf("%s: ", dev->sc_dev.dv_xname);
    396 	printf("csr == 0x%02i\n", csr);	/* XXX */
    397 }
    398 
    399 /*
    400  * select the bus, return when selected or error.
    401  */
    402 int
    403 sciselectbus(dev, target, our_addr)
    404         struct sci_softc *dev;
    405 	u_char target, our_addr;
    406 {
    407 	register int timeo = 2500;
    408 
    409 	QPRINTF (("sciselectbus %d\n", target));
    410 
    411 	/* if we're already selected, return */
    412 	if (dev->sc_flags & SCI_SELECTED)	/* XXXX */
    413 		return 1;
    414 
    415 	if ((*dev->sci_bus_csr & (SCI_BUS_BSY|SCI_BUS_SEL)) &&
    416 	    (*dev->sci_bus_csr & (SCI_BUS_BSY|SCI_BUS_SEL)) &&
    417 	    (*dev->sci_bus_csr & (SCI_BUS_BSY|SCI_BUS_SEL)))
    418 		return 1;
    419 
    420 	*dev->sci_tcmd = 0;
    421 	*dev->sci_odata = 0x80 + (1 << target);
    422 	*dev->sci_icmd = SCI_ICMD_DATA|SCI_ICMD_SEL;
    423 	while ((*dev->sci_bus_csr & SCI_BUS_BSY) == 0) {
    424 		if (--timeo > 0) {
    425 			delay(100);
    426 		} else {
    427 			break;
    428 		}
    429 	}
    430 	if (timeo) {
    431 		*dev->sci_icmd = 0;
    432 		dev->sc_flags |= SCI_SELECTED;
    433 		return (0);
    434 	}
    435 	*dev->sci_icmd = 0;
    436 	return (1);
    437 }
    438 
    439 int
    440 sci_ixfer_out(dev, len, buf, phase)
    441 	register struct sci_softc *dev;
    442 	int len;
    443 	register u_char *buf;
    444 	int phase;
    445 {
    446 	register int wait = sci_data_wait;
    447 	u_char csr;
    448 
    449 	QPRINTF(("sci_ixfer_out {%d} %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
    450 	  len, buf[0], buf[1], buf[2], buf[3], buf[4], buf[5],
    451 	  buf[6], buf[7], buf[8], buf[9]));
    452 
    453 	*dev->sci_tcmd = phase;
    454 	*dev->sci_icmd = SCI_ICMD_DATA;
    455 	for (;len > 0; len--) {
    456 		csr = *dev->sci_bus_csr;
    457 		while (!(csr & SCI_BUS_REQ)) {
    458 			if ((csr & SCI_BUS_BSY) == 0 || --wait < 0) {
    459 #ifdef DEBUG
    460 				if (sci_debug)
    461 					printf("sci_ixfer_out fail: l%d i%x w%d\n",
    462 					  len, csr, wait);
    463 #endif
    464 				return (len);
    465 			}
    466 			delay(1);
    467 			csr = *dev->sci_bus_csr;
    468 		}
    469 
    470 		if (!(*dev->sci_csr & SCI_CSR_PHASE_MATCH))
    471 			break;
    472 		*dev->sci_odata = *buf;
    473 		*dev->sci_icmd = SCI_ICMD_DATA|SCI_ICMD_ACK;
    474 		buf++;
    475 		while (*dev->sci_bus_csr & SCI_BUS_REQ);
    476 		*dev->sci_icmd = SCI_ICMD_DATA;
    477 	}
    478 
    479 	QPRINTF(("sci_ixfer_out done\n"));
    480 	return (0);
    481 }
    482 
    483 void
    484 sci_ixfer_in(dev, len, buf, phase)
    485 	struct sci_softc *dev;
    486 	int len;
    487 	register u_char *buf;
    488 	int phase;
    489 {
    490 	int wait = sci_data_wait;
    491 	u_char csr;
    492 	volatile register u_char *sci_bus_csr = dev->sci_bus_csr;
    493 	volatile register u_char *sci_data = dev->sci_data;
    494 	volatile register u_char *sci_icmd = dev->sci_icmd;
    495 #ifdef DEBUG
    496 	u_char *obp = buf;
    497 #endif
    498 
    499 	csr = *sci_bus_csr;
    500 
    501 	QPRINTF(("sci_ixfer_in %d, csr=%02x\n", len, csr));
    502 
    503 	*dev->sci_tcmd = phase;
    504 	*sci_icmd = 0;
    505 	for (;len > 0; len--) {
    506 		csr = *sci_bus_csr;
    507 		while (!(csr & SCI_BUS_REQ)) {
    508 			if (!(csr & SCI_BUS_BSY) || --wait < 0) {
    509 #ifdef DEBUG
    510 				if (sci_debug)
    511 					printf("sci_ixfer_in fail: l%d i%x w%d\n",
    512 					len, csr, wait);
    513 #endif
    514 				return;
    515 			}
    516 
    517 			delay(1);
    518 			csr = *sci_bus_csr;
    519 		}
    520 
    521 		if (!(*dev->sci_csr & SCI_CSR_PHASE_MATCH))
    522 			break;
    523 		*buf = *sci_data;
    524 		*sci_icmd = SCI_ICMD_ACK;
    525 		buf++;
    526 		while (*sci_bus_csr & SCI_BUS_REQ);
    527 		*sci_icmd = 0;
    528 	}
    529 
    530 	QPRINTF(("sci_ixfer_in {%d} %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
    531 	  len, obp[0], obp[1], obp[2], obp[3], obp[4], obp[5],
    532 	  obp[6], obp[7], obp[8], obp[9]));
    533 }
    534 
    535 /*
    536  * SCSI 'immediate' command:  issue a command to some SCSI device
    537  * and get back an 'immediate' response (i.e., do programmed xfer
    538  * to get the response data).  'cbuf' is a buffer containing a scsi
    539  * command of length clen bytes.  'buf' is a buffer of length 'len'
    540  * bytes for data.  The transfer direction is determined by the device
    541  * (i.e., by the scsi bus data xfer phase).  If 'len' is zero, the
    542  * command must supply no data.  'xferphase' is the bus phase the
    543  * caller expects to happen after the command is issued.  It should
    544  * be one of DATA_IN_PHASE, DATA_OUT_PHASE or STATUS_PHASE.
    545  */
    546 int
    547 sciicmd(dev, target, cbuf, clen, buf, len, xferphase)
    548 	struct sci_softc *dev;
    549 	void *cbuf, *buf;
    550 	int clen, len;
    551 	u_char xferphase;
    552 {
    553 	u_char phase;
    554 	register int wait;
    555 
    556 	/* select the SCSI bus (it's an error if bus isn't free) */
    557 	if (sciselectbus (dev, target, dev->sc_scsi_addr))
    558 		return -1;
    559 	/*
    560 	 * Wait for a phase change (or error) then let the device
    561 	 * sequence us through the various SCSI phases.
    562 	 */
    563 	dev->sc_stat[0] = 0xff;
    564 	dev->sc_msg[0] = 0xff;
    565 	phase = CMD_PHASE;
    566 	while (1) {
    567 		wait = sci_cmd_wait;
    568 
    569 		while ((*dev->sci_bus_csr & (SCI_BUS_REQ|SCI_BUS_BSY)) == SCI_BUS_BSY);
    570 
    571 		QPRINTF((">CSR:%02x<", *dev->sci_bus_csr));
    572 		if ((*dev->sci_bus_csr & SCI_BUS_REQ) == 0) {
    573 			return -1;
    574 		}
    575 		phase = SCI_PHASE(*dev->sci_bus_csr);
    576 
    577 		switch (phase) {
    578 		case CMD_PHASE:
    579 			if (sci_ixfer_out (dev, clen, cbuf, phase))
    580 				goto abort;
    581 			phase = xferphase;
    582 			break;
    583 
    584 		case DATA_IN_PHASE:
    585 			if (len <= 0)
    586 				goto abort;
    587 			wait = sci_data_wait;
    588 			sci_ixfer_in (dev, len, buf, phase);
    589 			phase = STATUS_PHASE;
    590 			break;
    591 
    592 		case DATA_OUT_PHASE:
    593 			if (len <= 0)
    594 				goto abort;
    595 			wait = sci_data_wait;
    596 			if (sci_ixfer_out (dev, len, buf, phase))
    597 				goto abort;
    598 			phase = STATUS_PHASE;
    599 			break;
    600 
    601 		case MESG_IN_PHASE:
    602 			dev->sc_msg[0] = 0xff;
    603 			sci_ixfer_in (dev, 1, dev->sc_msg,phase);
    604 			dev->sc_flags &= ~SCI_SELECTED;
    605 			while (*dev->sci_bus_csr & SCI_BUS_BSY);
    606 			goto out;
    607 			break;
    608 
    609 		case MESG_OUT_PHASE:
    610 			phase = STATUS_PHASE;
    611 			break;
    612 
    613 		case STATUS_PHASE:
    614 			sci_ixfer_in (dev, 1, dev->sc_stat, phase);
    615 			phase = MESG_IN_PHASE;
    616 			break;
    617 
    618 		case BUS_FREE_PHASE:
    619 			goto out;
    620 
    621 		default:
    622 		printf("sci: unexpected phase %d in icmd from %d\n",
    623 		  phase, target);
    624 		goto abort;
    625 		}
    626 #if 0
    627 		if (wait <= 0)
    628 			goto abort;
    629 #endif
    630 	}
    631 
    632 abort:
    633 	sciabort(dev, "icmd");
    634 out:
    635 	QPRINTF(("=STS:%02x=", dev->sc_stat[0]));
    636 	return (dev->sc_stat[0]);
    637 }
    638 
    639 int
    640 scigo(dev, xs)
    641 	struct sci_softc *dev;
    642 	struct scsi_xfer *xs;
    643 {
    644 	int count, target;
    645 	u_char phase, *addr;
    646 
    647 	target = xs->sc_link->target;
    648 	count = xs->datalen;
    649 	addr = xs->data;
    650 
    651 	if (sci_no_dma)	{
    652 		sciicmd (dev, target, (u_char *) xs->cmd, xs->cmdlen,
    653 		  addr, count,
    654 		  xs->flags & SCSI_DATA_IN ? DATA_IN_PHASE : DATA_OUT_PHASE);
    655 
    656 		return (1);
    657 	}
    658 
    659 	/* select the SCSI bus (it's an error if bus isn't free) */
    660 	if (sciselectbus (dev, target, dev->sc_scsi_addr))
    661 		return -1;
    662 	/*
    663 	 * Wait for a phase change (or error) then let the device
    664 	 * sequence us through the various SCSI phases.
    665 	 */
    666 	dev->sc_stat[0] = 0xff;
    667 	dev->sc_msg[0] = 0xff;
    668 	phase = CMD_PHASE;
    669 	while (1) {
    670 		while ((*dev->sci_bus_csr & (SCI_BUS_REQ|SCI_BUS_BSY)) ==
    671 		  SCI_BUS_BSY);
    672 
    673 		QPRINTF((">CSR:%02x<", *dev->sci_bus_csr));
    674 		if ((*dev->sci_bus_csr & SCI_BUS_REQ) == 0) {
    675 			goto abort;
    676 		}
    677 		phase = SCI_PHASE(*dev->sci_bus_csr);
    678 
    679 		switch (phase) {
    680 		case CMD_PHASE:
    681 			if (sci_ixfer_out (dev, xs->cmdlen, (u_char *) xs->cmd, phase))
    682 				goto abort;
    683 			phase = xs->flags & SCSI_DATA_IN ? DATA_IN_PHASE : DATA_OUT_PHASE;
    684 			break;
    685 
    686 		case DATA_IN_PHASE:
    687 			if (count <= 0)
    688 				goto abort;
    689 			/* XXX use psuedo DMA if available */
    690 			if (count >= 128 && dev->dma_xfer_in)
    691 				(*dev->dma_xfer_in)(dev, count, addr, phase);
    692 			else
    693 				sci_ixfer_in (dev, count, addr, phase);
    694 			phase = STATUS_PHASE;
    695 			break;
    696 
    697 		case DATA_OUT_PHASE:
    698 			if (count <= 0)
    699 				goto abort;
    700 			/* XXX use psuedo DMA if available */
    701 			if (count >= 128 && dev->dma_xfer_out)
    702 				(*dev->dma_xfer_out)(dev, count, addr, phase);
    703 			else
    704 				if (sci_ixfer_out (dev, count, addr, phase))
    705 					goto abort;
    706 			phase = STATUS_PHASE;
    707 			break;
    708 
    709 		case MESG_IN_PHASE:
    710 			dev->sc_msg[0] = 0xff;
    711 			sci_ixfer_in (dev, 1, dev->sc_msg,phase);
    712 			dev->sc_flags &= ~SCI_SELECTED;
    713 			while (*dev->sci_bus_csr & SCI_BUS_BSY);
    714 			goto out;
    715 			break;
    716 
    717 		case MESG_OUT_PHASE:
    718 			phase = STATUS_PHASE;
    719 			break;
    720 
    721 		case STATUS_PHASE:
    722 			sci_ixfer_in (dev, 1, dev->sc_stat, phase);
    723 			phase = MESG_IN_PHASE;
    724 			break;
    725 
    726 		case BUS_FREE_PHASE:
    727 			goto out;
    728 
    729 		default:
    730 		printf("sci: unexpected phase %d in icmd from %d\n",
    731 		  phase, target);
    732 		goto abort;
    733 		}
    734 	}
    735 
    736 abort:
    737 	sciabort(dev, "go");
    738 out:
    739 	QPRINTF(("=STS:%02x=", dev->sc_stat[0]));
    740 	return (1);
    741 }
    742