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sci.c revision 1.14
      1 /*	$NetBSD: sci.c,v 1.14 1995/09/29 13:52:02 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/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 scireset __P((struct sci_softc *));
     82 void scisetdelay __P((int));
     83 void sci_scsidone __P((struct sci_softc *, int));
     84 void sci_donextcmd __P((struct sci_softc *));
     85 
     86 int sci_cmd_wait = SCI_CMD_WAIT;
     87 int sci_data_wait = SCI_DATA_WAIT;
     88 int sci_init_wait = SCI_INIT_WAIT;
     89 
     90 int sci_no_dma = 0;
     91 
     92 #ifdef DEBUG
     93 #define QPRINTF(a) if (sci_debug > 1) printf a
     94 int	sci_debug = 0;
     95 #else
     96 #define QPRINTF
     97 #endif
     98 
     99 /*
    100  * default minphys routine for sci based controllers
    101  */
    102 void
    103 sci_minphys(bp)
    104 	struct buf *bp;
    105 {
    106 
    107 	/*
    108 	 * No max transfer at this level.
    109 	 */
    110 	minphys(bp);
    111 }
    112 
    113 /*
    114  * used by specific sci controller
    115  *
    116  * it appears that the higher level code does nothing with LUN's
    117  * so I will too.  I could plug it in, however so could they
    118  * in scsi_scsi_cmd().
    119  */
    120 int
    121 sci_scsicmd(xs)
    122 	struct scsi_xfer *xs;
    123 {
    124 	struct sci_pending *pendp;
    125 	struct sci_softc *dev;
    126 	struct scsi_link *slp;
    127 	int flags, s;
    128 
    129 	slp = xs->sc_link;
    130 	dev = slp->adapter_softc;
    131 	flags = xs->flags;
    132 
    133 	if (flags & SCSI_DATA_UIO)
    134 		panic("sci: scsi data uio requested");
    135 
    136 	if (dev->sc_xs && flags & SCSI_POLL)
    137 		panic("sci_scsicmd: busy");
    138 
    139 	s = splbio();
    140 	pendp = &dev->sc_xsstore[slp->target][slp->lun];
    141 	if (pendp->xs) {
    142 		splx(s);
    143 		return(TRY_AGAIN_LATER);
    144 	}
    145 
    146 	if (dev->sc_xs) {
    147 		pendp->xs = xs;
    148 		TAILQ_INSERT_TAIL(&dev->sc_xslist, pendp, link);
    149 		splx(s);
    150 		return(SUCCESSFULLY_QUEUED);
    151 	}
    152 	pendp->xs = NULL;
    153 	dev->sc_xs = xs;
    154 	splx(s);
    155 
    156 	/*
    157 	 * nothing is pending do it now.
    158 	 */
    159 	sci_donextcmd(dev);
    160 
    161 	if (flags & SCSI_POLL)
    162 		return(COMPLETE);
    163 	return(SUCCESSFULLY_QUEUED);
    164 }
    165 
    166 /*
    167  * entered with dev->sc_xs pointing to the next xfer to perform
    168  */
    169 void
    170 sci_donextcmd(dev)
    171 	struct sci_softc *dev;
    172 {
    173 	struct scsi_xfer *xs;
    174 	struct scsi_link *slp;
    175 	int flags, phase, stat;
    176 
    177 	xs = dev->sc_xs;
    178 	slp = xs->sc_link;
    179 	flags = xs->flags;
    180 
    181 	if (flags & SCSI_DATA_IN)
    182 		phase = DATA_IN_PHASE;
    183 	else if (flags & SCSI_DATA_OUT)
    184 		phase = DATA_OUT_PHASE;
    185 	else
    186 		phase = STATUS_PHASE;
    187 
    188 	if (flags & SCSI_RESET)
    189 		scireset(dev);
    190 
    191 	dev->sc_stat[0] = -1;
    192 	xs->cmd->bytes[0] |= slp->lun << 5;
    193 	if (phase == STATUS_PHASE || flags & SCSI_POLL)
    194 		stat = sciicmd(dev, slp->target, xs->cmd, xs->cmdlen,
    195 		    xs->data, xs->datalen, phase);
    196 	else if (scigo(dev, xs) == 0)
    197 		return;
    198 	else
    199 		stat = dev->sc_stat[0];
    200 
    201 	sci_scsidone(dev, stat);
    202 }
    203 
    204 void
    205 sci_scsidone(dev, stat)
    206 	struct sci_softc *dev;
    207 	int stat;
    208 {
    209 	struct sci_pending *pendp;
    210 	struct scsi_xfer *xs;
    211 	int s, donext;
    212 
    213 	xs = dev->sc_xs;
    214 #ifdef DIAGNOSTIC
    215 	if (xs == NULL)
    216 		panic("sci_scsidone");
    217 #endif
    218 	if (xs->sc_link->device_softc &&
    219 	    ((struct device *)(xs->sc_link->device_softc))->dv_unit < dk_ndrive)
    220 		++dk_xfer[((struct device *)(xs->sc_link->device_softc))->dv_unit];
    221 	/*
    222 	 * is this right?
    223 	 */
    224 	xs->status = stat;
    225 
    226 	if (stat == 0)
    227 		xs->resid = 0;
    228 	else {
    229 		switch(stat) {
    230 		case SCSI_CHECK:
    231 			if (stat = scigetsense(dev, xs))
    232 				goto bad_sense;
    233 			xs->error = XS_SENSE;
    234 			break;
    235 		case SCSI_BUSY:
    236 			xs->error = XS_BUSY;
    237 			break;
    238 		bad_sense:
    239 		default:
    240 			xs->error = XS_DRIVER_STUFFUP;
    241 			QPRINTF(("sci_scsicmd() bad %x\n", stat));
    242 			break;
    243 		}
    244 	}
    245 	xs->flags |= ITSDONE;
    246 
    247 	/*
    248 	 * grab next command before scsi_done()
    249 	 * this way no single device can hog scsi resources.
    250 	 */
    251 	s = splbio();
    252 	pendp = dev->sc_xslist.tqh_first;
    253 	if (pendp == NULL) {
    254 		donext = 0;
    255 		dev->sc_xs = NULL;
    256 	} else {
    257 		donext = 1;
    258 		TAILQ_REMOVE(&dev->sc_xslist, pendp, link);
    259 		dev->sc_xs = pendp->xs;
    260 		pendp->xs = NULL;
    261 	}
    262 	splx(s);
    263 	scsi_done(xs);
    264 
    265 	if (donext)
    266 		sci_donextcmd(dev);
    267 }
    268 
    269 int
    270 scigetsense(dev, xs)
    271 	struct sci_softc *dev;
    272 	struct scsi_xfer *xs;
    273 {
    274 	struct scsi_sense rqs;
    275 	struct scsi_link *slp;
    276 	int stat;
    277 
    278 	slp = xs->sc_link;
    279 
    280 	rqs.opcode = REQUEST_SENSE;
    281 	rqs.byte2 = slp->lun << 5;
    282 #ifdef not_yet
    283 	rqs.length = xs->req_sense_length ? xs->req_sense_length :
    284 	    sizeof(xs->sense);
    285 #else
    286 	rqs.length = sizeof(xs->sense);
    287 #endif
    288 
    289 	rqs.unused[0] = rqs.unused[1] = rqs.control = 0;
    290 
    291 	return(sciicmd(dev, slp->target, &rqs, sizeof(rqs), &xs->sense,
    292 	    rqs.length, DATA_IN_PHASE));
    293 }
    294 
    295 void
    296 sciabort(dev, where)
    297 	struct sci_softc *dev;
    298 	char *where;
    299 {
    300 	printf ("%s: abort %s: csr = 0x%02x, bus = 0x%02x\n",
    301 	  dev->sc_dev.dv_xname, where, *dev->sci_csr, *dev->sci_bus_csr);
    302 
    303 	if (dev->sc_flags & SCI_SELECTED) {
    304 
    305 		/* lets just hope it worked.. */
    306 		dev->sc_flags &= ~SCI_SELECTED;
    307 		/* XXX */
    308 		scireset (dev);
    309 	}
    310 }
    311 
    312 /*
    313  * XXX Set/reset long delays.
    314  *
    315  * if delay == 0, reset default delays
    316  * if delay < 0,  set both delays to default long initialization values
    317  * if delay > 0,  set both delays to this value
    318  *
    319  * Used when a devices is expected to respond slowly (e.g. during
    320  * initialization).
    321  */
    322 void
    323 scisetdelay(del)
    324 	int del;
    325 {
    326 	static int saved_cmd_wait, saved_data_wait;
    327 
    328 	if (del) {
    329 		saved_cmd_wait = sci_cmd_wait;
    330 		saved_data_wait = sci_data_wait;
    331 		if (del > 0)
    332 			sci_cmd_wait = sci_data_wait = del;
    333 		else
    334 			sci_cmd_wait = sci_data_wait = sci_init_wait;
    335 	} else {
    336 		sci_cmd_wait = saved_cmd_wait;
    337 		sci_data_wait = saved_data_wait;
    338 	}
    339 }
    340 
    341 void
    342 scireset(dev)
    343 	struct sci_softc *dev;
    344 {
    345 	u_int i, s;
    346 	u_char my_id, csr;
    347 
    348 	dev->sc_flags &= ~SCI_SELECTED;
    349 	if (dev->sc_flags & SCI_ALIVE)
    350 		sciabort(dev, "reset");
    351 
    352 	printf("%s: ", dev->sc_dev.dv_xname);
    353 
    354 	s = splbio();
    355 	/* preserve our ID for now */
    356 	my_id = 7;
    357 
    358 	/*
    359 	 * Reset the chip
    360 	 */
    361 	*dev->sci_icmd = SCI_ICMD_TEST;
    362 	*dev->sci_icmd = SCI_ICMD_TEST | SCI_ICMD_RST;
    363 	delay (25);
    364 	*dev->sci_icmd = 0;
    365 
    366 	/*
    367 	 * Set up various chip parameters
    368 	 */
    369 	*dev->sci_icmd = 0;
    370 	*dev->sci_tcmd = 0;
    371 	*dev->sci_sel_enb = 0;
    372 
    373 	/* anything else was zeroed by reset */
    374 
    375 	splx (s);
    376 
    377 	printf("sci id %d\n", my_id);
    378 	dev->sc_flags |= SCI_ALIVE;
    379 }
    380 
    381 void
    382 scierror(dev, csr)
    383 	struct sci_softc *dev;
    384 	u_char csr;
    385 {
    386 	struct scsi_xfer *xs;
    387 
    388 	xs = dev->sc_xs;
    389 
    390 #ifdef DIAGNOSTIC
    391 	if (xs == NULL)
    392 		panic("scierror");
    393 #endif
    394 	if (xs->flags & SCSI_SILENT)
    395 		return;
    396 
    397 	printf("%s: ", dev->sc_dev.dv_xname);
    398 	printf("csr == 0x%02i\n", csr);	/* XXX */
    399 }
    400 
    401 /*
    402  * select the bus, return when selected or error.
    403  */
    404 int
    405 sciselectbus(dev, target, our_addr)
    406         struct sci_softc *dev;
    407 	u_char target, our_addr;
    408 {
    409 	register int timeo = 2500;
    410 
    411 	QPRINTF (("sciselectbus %d\n", target));
    412 
    413 	/* if we're already selected, return */
    414 	if (dev->sc_flags & SCI_SELECTED)	/* XXXX */
    415 		return 1;
    416 
    417 	if ((*dev->sci_bus_csr & (SCI_BUS_BSY|SCI_BUS_SEL)) &&
    418 	    (*dev->sci_bus_csr & (SCI_BUS_BSY|SCI_BUS_SEL)) &&
    419 	    (*dev->sci_bus_csr & (SCI_BUS_BSY|SCI_BUS_SEL)))
    420 		return 1;
    421 
    422 	*dev->sci_tcmd = 0;
    423 	*dev->sci_odata = 0x80 + (1 << target);
    424 	*dev->sci_icmd = SCI_ICMD_DATA|SCI_ICMD_SEL;
    425 	while ((*dev->sci_bus_csr & SCI_BUS_BSY) == 0) {
    426 		if (--timeo > 0) {
    427 			delay(100);
    428 		} else {
    429 			break;
    430 		}
    431 	}
    432 	if (timeo) {
    433 		*dev->sci_icmd = 0;
    434 		dev->sc_flags |= SCI_SELECTED;
    435 		return (0);
    436 	}
    437 	*dev->sci_icmd = 0;
    438 	return (1);
    439 }
    440 
    441 int
    442 sci_ixfer_out(dev, len, buf, phase)
    443 	register struct sci_softc *dev;
    444 	int len;
    445 	register u_char *buf;
    446 	int phase;
    447 {
    448 	register int wait = sci_data_wait;
    449 	u_char csr;
    450 
    451 	QPRINTF(("sci_ixfer_out {%d} %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
    452 	  len, buf[0], buf[1], buf[2], buf[3], buf[4], buf[5],
    453 	  buf[6], buf[7], buf[8], buf[9]));
    454 
    455 	*dev->sci_tcmd = phase;
    456 	*dev->sci_icmd = SCI_ICMD_DATA;
    457 	for (;len > 0; len--) {
    458 		csr = *dev->sci_bus_csr;
    459 		while (!(csr & SCI_BUS_REQ)) {
    460 			if ((csr & SCI_BUS_BSY) == 0 || --wait < 0) {
    461 #ifdef DEBUG
    462 				if (sci_debug)
    463 					printf("sci_ixfer_out fail: l%d i%x w%d\n",
    464 					  len, csr, wait);
    465 #endif
    466 				return (len);
    467 			}
    468 			delay(1);
    469 			csr = *dev->sci_bus_csr;
    470 		}
    471 
    472 		if (!(*dev->sci_csr & SCI_CSR_PHASE_MATCH))
    473 			break;
    474 		*dev->sci_odata = *buf;
    475 		*dev->sci_icmd = SCI_ICMD_DATA|SCI_ICMD_ACK;
    476 		buf++;
    477 		while (*dev->sci_bus_csr & SCI_BUS_REQ);
    478 		*dev->sci_icmd = SCI_ICMD_DATA;
    479 	}
    480 
    481 	QPRINTF(("sci_ixfer_out done\n"));
    482 	return (0);
    483 }
    484 
    485 void
    486 sci_ixfer_in(dev, len, buf, phase)
    487 	struct sci_softc *dev;
    488 	int len;
    489 	register u_char *buf;
    490 	int phase;
    491 {
    492 	int wait = sci_data_wait;
    493 	u_char *obp = buf;
    494 	u_char csr;
    495 	volatile register u_char *sci_bus_csr = dev->sci_bus_csr;
    496 	volatile register u_char *sci_data = dev->sci_data;
    497 	volatile register u_char *sci_icmd = dev->sci_icmd;
    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, csr, asr;
    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 i, count, target;
    645 	u_char phase, csr, asr, cmd, *addr;
    646 	int wait;
    647 
    648 	target = xs->sc_link->target;
    649 	count = xs->datalen;
    650 	addr = xs->data;
    651 
    652 	if (sci_no_dma)	{
    653 		sciicmd (dev, target, (u_char *) xs->cmd, xs->cmdlen,
    654 		  addr, count,
    655 		  xs->flags & SCSI_DATA_IN ? DATA_IN_PHASE : DATA_OUT_PHASE);
    656 
    657 		return (1);
    658 	}
    659 
    660 	/* select the SCSI bus (it's an error if bus isn't free) */
    661 	if (sciselectbus (dev, target, dev->sc_scsi_addr))
    662 		return -1;
    663 	/*
    664 	 * Wait for a phase change (or error) then let the device
    665 	 * sequence us through the various SCSI phases.
    666 	 */
    667 	dev->sc_stat[0] = 0xff;
    668 	dev->sc_msg[0] = 0xff;
    669 	phase = CMD_PHASE;
    670 	while (1) {
    671 		while ((*dev->sci_bus_csr & (SCI_BUS_REQ|SCI_BUS_BSY)) ==
    672 		  SCI_BUS_BSY);
    673 
    674 		QPRINTF((">CSR:%02x<", *dev->sci_bus_csr));
    675 		if ((*dev->sci_bus_csr & SCI_BUS_REQ) == 0) {
    676 			goto abort;
    677 		}
    678 		phase = SCI_PHASE(*dev->sci_bus_csr);
    679 
    680 		switch (phase) {
    681 		case CMD_PHASE:
    682 			if (sci_ixfer_out (dev, xs->cmdlen, xs->cmd, phase))
    683 				goto abort;
    684 			phase = xs->flags & SCSI_DATA_IN ? DATA_IN_PHASE : DATA_OUT_PHASE;
    685 			break;
    686 
    687 		case DATA_IN_PHASE:
    688 			if (count <= 0)
    689 				goto abort;
    690 			/* XXX use psuedo DMA if available */
    691 			if (count >= 128 && dev->dma_xfer_in)
    692 				(*dev->dma_xfer_in)(dev, count, addr, phase);
    693 			else
    694 				sci_ixfer_in (dev, count, addr, phase);
    695 			phase = STATUS_PHASE;
    696 			break;
    697 
    698 		case DATA_OUT_PHASE:
    699 			if (count <= 0)
    700 				goto abort;
    701 			/* XXX use psuedo DMA if available */
    702 			if (count >= 128 && dev->dma_xfer_out)
    703 				(*dev->dma_xfer_out)(dev, count, addr, phase);
    704 			else
    705 				if (sci_ixfer_out (dev, count, addr, phase))
    706 					goto abort;
    707 			phase = STATUS_PHASE;
    708 			break;
    709 
    710 		case MESG_IN_PHASE:
    711 			dev->sc_msg[0] = 0xff;
    712 			sci_ixfer_in (dev, 1, dev->sc_msg,phase);
    713 			dev->sc_flags &= ~SCI_SELECTED;
    714 			while (*dev->sci_bus_csr & SCI_BUS_BSY);
    715 			goto out;
    716 			break;
    717 
    718 		case MESG_OUT_PHASE:
    719 			phase = STATUS_PHASE;
    720 			break;
    721 
    722 		case STATUS_PHASE:
    723 			sci_ixfer_in (dev, 1, dev->sc_stat, phase);
    724 			phase = MESG_IN_PHASE;
    725 			break;
    726 
    727 		case BUS_FREE_PHASE:
    728 			goto out;
    729 
    730 		default:
    731 		printf("sci: unexpected phase %d in icmd from %d\n",
    732 		  phase, target);
    733 		goto abort;
    734 		}
    735 	}
    736 
    737 abort:
    738 	sciabort(dev, "go");
    739 out:
    740 	QPRINTF(("=STS:%02x=", dev->sc_stat[0]));
    741 	return (1);
    742 }
    743