xref: /netbsd-src/sys/arch/hp300/dev/mt.c (revision de1dfb1250df962f1ff3a011772cf58e605aed11)
1 /*	$NetBSD: mt.c,v 1.25 2004/08/28 17:37:02 thorpej Exp $	*/
2 
3 /*-
4  * Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the NetBSD
21  *	Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Copyright (c) 1992, The University of Utah and
41  * the Computer Systems Laboratory at the University of Utah (CSL).
42  * All rights reserved.
43  *
44  * Permission to use, copy, modify and distribute this software is hereby
45  * granted provided that (1) source code retains these copyright, permission,
46  * and disclaimer notices, and (2) redistributions including binaries
47  * reproduce the notices in supporting documentation, and (3) all advertising
48  * materials mentioning features or use of this software display the following
49  * acknowledgement: ``This product includes software developed by the
50  * Computer Systems Laboratory at the University of Utah.''
51  *
52  * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
53  * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
54  * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
55  *
56  * CSL requests users of this software to return to csl-dist@cs.utah.edu any
57  * improvements that they make and grant CSL redistribution rights.
58  *
59  *	Utah $Hdr: mt.c 1.8 95/09/12$
60  */
61 /*	@(#)mt.c	3.9	90/07/10	mt Xinu
62  *
63  * Magnetic tape driver (7974a, 7978a/b, 7979a, 7980a, 7980xc)
64  * Original version contributed by Mt. Xinu.
65  * Modified for 4.4BSD by Mark Davies and Andrew Vignaux, Department of
66  * Computer Science, Victoria University of Wellington
67  */
68 
69 #include <sys/cdefs.h>
70 __KERNEL_RCSID(0, "$NetBSD: mt.c,v 1.25 2004/08/28 17:37:02 thorpej Exp $");
71 
72 #include <sys/param.h>
73 #include <sys/systm.h>
74 #include <sys/callout.h>
75 #include <sys/buf.h>
76 #include <sys/ioctl.h>
77 #include <sys/mtio.h>
78 #include <sys/file.h>
79 #include <sys/proc.h>
80 #include <sys/errno.h>
81 #include <sys/syslog.h>
82 #include <sys/tty.h>
83 #include <sys/kernel.h>
84 #include <sys/tprintf.h>
85 #include <sys/device.h>
86 #include <sys/conf.h>
87 
88 #include <hp300/dev/hpibvar.h>
89 
90 #include <hp300/dev/mtreg.h>
91 
92 static const struct mtinfo {
93 	u_short	hwid;
94 	char	*desc;
95 } mtinfo[] = {
96 	{ MT7978ID,	"7978"	},
97 	{ MT7979AID,	"7979A"	},
98 	{ MT7980ID,	"7980"	},
99 	{ MT7974AID,	"7974A"	},
100 };
101 static const int nmtinfo = sizeof(mtinfo) / sizeof(mtinfo[0]);
102 
103 struct	mt_softc {
104 	struct	device sc_dev;
105 	struct	callout sc_start_ch;
106 	struct	callout sc_intr_ch;
107 	int	sc_hpibno;	/* logical HPIB this slave it attached to */
108 	int	sc_slave;	/* HPIB slave address (0-6) */
109 	short	sc_flags;	/* see below */
110 	u_char	sc_lastdsj;	/* place for DSJ in mtreaddsj() */
111 	u_char	sc_lastecmd;	/* place for End Command in mtreaddsj() */
112 	short	sc_recvtimeo;	/* count of hpibsend timeouts to prevent hang */
113 	short	sc_statindex;	/* index for next sc_stat when MTF_STATTIMEO */
114 	struct	mt_stat sc_stat;/* status bytes last read from device */
115 	short	sc_density;	/* current density of tape (mtio.h format) */
116 	short	sc_type;	/* tape drive model (hardware IDs) */
117 	struct	hpibqueue sc_hq; /* HPIB device queue member */
118 	tpr_t	sc_ttyp;
119 	struct bufq_state sc_tab;/* buf queue */
120 	int	sc_active;
121 	struct buf sc_bufstore;	/* XXX buffer storage */
122 };
123 
124 #ifdef DEBUG
125 int	mtdebug = 0;
126 #define	dlog	if (mtdebug) log
127 #else
128 #define	dlog	if (0) log
129 #endif
130 
131 #define	UNIT(x)		(minor(x) & 3)
132 
133 #define B_CMD		B_XXX		/* command buf instead of data */
134 #define	b_cmd		b_blkno		/* blkno holds cmd when B_CMD */
135 
136 static int	mtmatch(struct device *, struct cfdata *, void *);
137 static void	mtattach(struct device *, struct device *, void *);
138 
139 CFATTACH_DECL(mt, sizeof(struct mt_softc),
140     mtmatch, mtattach, NULL, NULL);
141 
142 extern struct cfdriver mt_cd;
143 
144 static dev_type_open(mtopen);
145 static dev_type_close(mtclose);
146 static dev_type_read(mtread);
147 static dev_type_write(mtwrite);
148 static dev_type_ioctl(mtioctl);
149 static dev_type_strategy(mtstrategy);
150 
151 const struct bdevsw mt_bdevsw = {
152 	mtopen, mtclose, mtstrategy, mtioctl, nodump, nosize, D_TAPE
153 };
154 
155 const struct cdevsw mt_cdevsw = {
156 	mtopen, mtclose, mtread, mtwrite, mtioctl,
157 	nostop, notty, nopoll, nommap, nokqfilter, D_TAPE
158 };
159 
160 static int	mtident(struct mt_softc *, struct hpibbus_attach_args *);
161 static void	mtustart(struct mt_softc *);
162 static int	mtreaddsj(struct mt_softc *, int);
163 static int	mtcommand(dev_t, int, int);
164 static void	spl_mtintr(void *);
165 static void	spl_mtstart(void *);
166 
167 static void	mtstart(void *);
168 static void	mtgo(void *);
169 static void	mtintr(void *);
170 
171 static int
172 mtmatch(struct device *parent, struct cfdata *match, void *aux)
173 {
174 	struct hpibbus_attach_args *ha = aux;
175 
176 	return (mtident(NULL, ha));
177 }
178 
179 static void
180 mtattach(struct device *parent, struct device *self, void *aux)
181 {
182 	struct mt_softc *sc = (struct mt_softc *)self;
183 	struct hpibbus_attach_args *ha = aux;
184 	int unit, hpibno, slave;
185 
186 	if (mtident(sc, ha) == 0) {
187 		printf("\n%s: impossible!\n", sc->sc_dev.dv_xname);
188 		return;
189 	}
190 
191 	unit = self->dv_unit;
192 	hpibno = parent->dv_unit;
193 	slave = ha->ha_slave;
194 
195 	bufq_alloc(&sc->sc_tab, BUFQ_FCFS);
196 	callout_init(&sc->sc_start_ch);
197 	callout_init(&sc->sc_intr_ch);
198 
199 	sc->sc_hpibno = hpibno;
200 	sc->sc_slave = slave;
201 	sc->sc_flags = MTF_EXISTS;
202 
203 	/* Initialize hpib job queue entry. */
204 	sc->sc_hq.hq_softc = sc;
205 	sc->sc_hq.hq_slave = sc->sc_slave;
206 	sc->sc_hq.hq_start = mtstart;
207 	sc->sc_hq.hq_go = mtgo;
208 	sc->sc_hq.hq_intr = mtintr;
209 }
210 
211 static int
212 mtident(struct mt_softc *sc, struct hpibbus_attach_args *ha)
213 {
214 	int i;
215 
216 	for (i = 0; i < nmtinfo; i++) {
217 		if (ha->ha_id == mtinfo[i].hwid) {
218 			if (sc != NULL) {
219 				sc->sc_type = mtinfo[i].hwid;
220 				printf(": %s tape\n", mtinfo[i].desc);
221 			}
222 			return (1);
223 		}
224 	}
225 	return (0);
226 }
227 
228 /*
229  * Perform a read of "Device Status Jump" register and update the
230  * status if necessary.  If status is read, the given "ecmd" is also
231  * performed, unless "ecmd" is zero.  Returns DSJ value, -1 on failure
232  * and -2 on "temporary" failure.
233  */
234 static int
235 mtreaddsj(struct mt_softc *sc, int ecmd)
236 {
237 	int retval;
238 
239 	if (sc->sc_flags & MTF_STATTIMEO)
240 		goto getstats;
241 	retval = hpibrecv(sc->sc_hpibno,
242 	    (sc->sc_flags & MTF_DSJTIMEO) ? -1 : sc->sc_slave,
243 	    MTT_DSJ, &(sc->sc_lastdsj), 1);
244 	sc->sc_flags &= ~MTF_DSJTIMEO;
245 	if (retval != 1) {
246 		dlog(LOG_DEBUG, "%s can't hpibrecv DSJ",
247 		    sc->sc_dev.dv_xname);
248 		if (sc->sc_recvtimeo == 0)
249 			sc->sc_recvtimeo = hz;
250 		if (--sc->sc_recvtimeo == 0)
251 			return (-1);
252 		if (retval == 0)
253 			sc->sc_flags |= MTF_DSJTIMEO;
254 		return (-2);
255 	}
256 	sc->sc_recvtimeo = 0;
257 	sc->sc_statindex = 0;
258 	dlog(LOG_DEBUG, "%s readdsj: 0x%x", sc->sc_dev.dv_xname,
259 	    sc->sc_lastdsj);
260 	sc->sc_lastecmd = ecmd;
261 	switch (sc->sc_lastdsj) {
262 	    case 0:
263 		if (ecmd & MTE_DSJ_FORCE)
264 			break;
265 		return (0);
266 
267 	    case 2:
268 		sc->sc_lastecmd = MTE_COMPLETE;
269 	    case 1:
270 		break;
271 
272 	    default:
273 		log(LOG_ERR, "%s readdsj: DSJ 0x%x\n", sc->sc_dev.dv_xname,
274 		    sc->sc_lastdsj);
275 		return (-1);
276 	}
277     getstats:
278 	retval = hpibrecv(sc->sc_hpibno,
279 	    (sc->sc_flags & MTF_STATCONT) ? -1 : sc->sc_slave,
280 	    MTT_STAT, ((char *)&(sc->sc_stat)) + sc->sc_statindex,
281 	    sizeof(sc->sc_stat) - sc->sc_statindex);
282 	sc->sc_flags &= ~(MTF_STATTIMEO | MTF_STATCONT);
283 	if (retval != sizeof(sc->sc_stat) - sc->sc_statindex) {
284 		if (sc->sc_recvtimeo == 0)
285 			sc->sc_recvtimeo = hz;
286 		if (--sc->sc_recvtimeo != 0) {
287 			if (retval >= 0) {
288 				sc->sc_statindex += retval;
289 				sc->sc_flags |= MTF_STATCONT;
290 			}
291 			sc->sc_flags |= MTF_STATTIMEO;
292 			return (-2);
293 		}
294 		log(LOG_ERR, "%s readdsj: can't read status",
295 		    sc->sc_dev.dv_xname);
296 		return (-1);
297 	}
298 	sc->sc_recvtimeo = 0;
299 	sc->sc_statindex = 0;
300 	dlog(LOG_DEBUG, "%s readdsj: status is %x %x %x %x %x %x",
301 	    sc->sc_dev.dv_xname,
302 	    sc->sc_stat1, sc->sc_stat2, sc->sc_stat3,
303 	    sc->sc_stat4, sc->sc_stat5, sc->sc_stat6);
304 	if (sc->sc_lastecmd)
305 		(void) hpibsend(sc->sc_hpibno, sc->sc_slave,
306 		    MTL_ECMD, &(sc->sc_lastecmd), 1);
307 	return ((int) sc->sc_lastdsj);
308 }
309 
310 static int
311 mtopen(dev_t dev, int flag, int mode, struct proc *p)
312 {
313 	int unit = UNIT(dev);
314 	struct mt_softc *sc;
315 	int req_den;
316 	int error;
317 
318 	if (unit >= mt_cd.cd_ndevs ||
319 	    (sc = mt_cd.cd_devs[unit]) == NULL ||
320 	    (sc->sc_flags & MTF_EXISTS) == 0)
321 		return (ENXIO);
322 
323 	dlog(LOG_DEBUG, "%s open: flags 0x%x", sc->sc_dev.dv_xname,
324 	    sc->sc_flags);
325 	if (sc->sc_flags & MTF_OPEN)
326 		return (EBUSY);
327 	sc->sc_flags |= MTF_OPEN;
328 	sc->sc_ttyp = tprintf_open(p);
329 	if ((sc->sc_flags & MTF_ALIVE) == 0) {
330 		error = mtcommand(dev, MTRESET, 0);
331 		if (error != 0 || (sc->sc_flags & MTF_ALIVE) == 0)
332 			goto errout;
333 		if ((sc->sc_stat1 & (SR1_BOT | SR1_ONLINE)) == SR1_ONLINE)
334 			(void) mtcommand(dev, MTREW, 0);
335 	}
336 	for (;;) {
337 		if ((error = mtcommand(dev, MTNOP, 0)) != 0)
338 			goto errout;
339 		if (!(sc->sc_flags & MTF_REW))
340 			break;
341 		if (tsleep((caddr_t) &lbolt, PCATCH | (PZERO + 1),
342 		    "mt", 0) != 0) {
343 			error = EINTR;
344 			goto errout;
345 		}
346 	}
347 	if ((flag & FWRITE) && (sc->sc_stat1 & SR1_RO)) {
348 		error = EROFS;
349 		goto errout;
350 	}
351 	if (!(sc->sc_stat1 & SR1_ONLINE)) {
352 		uprintf("%s: not online\n", sc->sc_dev.dv_xname);
353 		error = EIO;
354 		goto errout;
355 	}
356 	/*
357 	 * Select density:
358 	 *  - find out what density the drive is set to
359 	 *	(i.e. the density of the current tape)
360 	 *  - if we are going to write
361 	 *    - if we're not at the beginning of the tape
362 	 *      - complain if we want to change densities
363 	 *    - otherwise, select the mtcommand to set the density
364 	 *
365 	 * If the drive doesn't support it then don't change the recorded
366 	 * density.
367 	 *
368 	 * The original MOREbsd code had these additional conditions
369 	 * for the mid-tape change
370 	 *
371 	 *	req_den != T_BADBPI &&
372 	 *	sc->sc_density != T_6250BPI
373 	 *
374 	 * which suggests that it would be possible to write multiple
375 	 * densities if req_den == T_BAD_BPI or the current tape
376 	 * density was 6250.  Testing of our 7980 suggests that the
377 	 * device cannot change densities mid-tape.
378 	 *
379 	 * ajv@comp.vuw.ac.nz
380 	 */
381 	sc->sc_density = (sc->sc_stat2 & SR2_6250) ? T_6250BPI : (
382 			 (sc->sc_stat3 & SR3_1600) ? T_1600BPI : (
383 			 (sc->sc_stat3 & SR3_800) ? T_800BPI : -1));
384 	req_den = (dev & T_DENSEL);
385 
386 	if (flag & FWRITE) {
387 		if (!(sc->sc_stat1 & SR1_BOT)) {
388 			if (sc->sc_density != req_den) {
389 				uprintf("%s: can't change density mid-tape\n",
390 				    sc->sc_dev.dv_xname);
391 				error = EIO;
392 				goto errout;
393 			}
394 		}
395 		else {
396 			int mtset_density =
397 			    (req_den == T_800BPI  ? MTSET800BPI : (
398 			     req_den == T_1600BPI ? MTSET1600BPI : (
399 			     req_den == T_6250BPI ? MTSET6250BPI : (
400 			     sc->sc_type == MT7980ID
401 						  ? MTSET6250DC
402 						  : MTSET6250BPI))));
403 			if (mtcommand(dev, mtset_density, 0) == 0)
404 				sc->sc_density = req_den;
405 		}
406 	}
407 	return (0);
408 errout:
409 	sc->sc_flags &= ~MTF_OPEN;
410 	return (error);
411 }
412 
413 static int
414 mtclose(dev_t dev, int flag, int fmt, struct proc *p)
415 {
416 	struct mt_softc *sc = mt_cd.cd_devs[UNIT(dev)];
417 
418 	if (sc->sc_flags & MTF_WRT) {
419 		(void) mtcommand(dev, MTWEOF, 2);
420 		(void) mtcommand(dev, MTBSF, 0);
421 	}
422 	if ((minor(dev) & T_NOREWIND) == 0)
423 		(void) mtcommand(dev, MTREW, 0);
424 	sc->sc_flags &= ~MTF_OPEN;
425 	tprintf_close(sc->sc_ttyp);
426 	return (0);
427 }
428 
429 static int
430 mtcommand(dev_t dev, int cmd, int cnt)
431 {
432 	struct mt_softc *sc = mt_cd.cd_devs[UNIT(dev)];
433 	struct buf *bp = &sc->sc_bufstore;
434 	int error = 0;
435 
436 #if 1
437 	if (bp->b_flags & B_BUSY)
438 		return (EBUSY);
439 #endif
440 	bp->b_cmd = cmd;
441 	bp->b_dev = dev;
442 	do {
443 		bp->b_flags = B_BUSY | B_CMD;
444 		mtstrategy(bp);
445 		biowait(bp);
446 		if (bp->b_flags & B_ERROR) {
447 			error = (int) (unsigned) bp->b_error;
448 			break;
449 		}
450 	} while (--cnt > 0);
451 #if 0
452 	bp->b_flags = 0 /*&= ~B_BUSY*/;
453 #else
454 	bp->b_flags &= ~B_BUSY;
455 #endif
456 	return (error);
457 }
458 
459 /*
460  * Only thing to check here is for legal record lengths (writes only).
461  */
462 static void
463 mtstrategy(struct buf *bp)
464 {
465 	struct mt_softc *sc;
466 	int unit;
467 	int s;
468 
469 	unit = UNIT(bp->b_dev);
470 	sc = mt_cd.cd_devs[unit];
471 	dlog(LOG_DEBUG, "%s strategy", sc->sc_dev.dv_xname);
472 	if ((bp->b_flags & (B_CMD | B_READ)) == 0) {
473 #define WRITE_BITS_IGNORED	8
474 #if 0
475 		if (bp->b_bcount & ((1 << WRITE_BITS_IGNORED) - 1)) {
476 			tprintf(sc->sc_ttyp,
477 				"%s: write record must be multiple of %d\n",
478 				sc->sc_dev.dv_xname, 1 << WRITE_BITS_IGNORED);
479 			goto error;
480 		}
481 #endif
482 		s = 16 * 1024;
483 		if (sc->sc_stat2 & SR2_LONGREC) {
484 			switch (sc->sc_density) {
485 			    case T_1600BPI:
486 				s = 32 * 1024;
487 				break;
488 
489 			    case T_6250BPI:
490 			    case T_BADBPI:
491 				s = 60 * 1024;
492 				break;
493 			}
494 		}
495 		if (bp->b_bcount > s) {
496 			tprintf(sc->sc_ttyp,
497 				"%s: write record (%ld) too big: limit (%d)\n",
498 				sc->sc_dev.dv_xname, bp->b_bcount, s);
499 #if 0 /* XXX see above */
500 	    error:
501 #endif
502 			bp->b_flags |= B_ERROR;
503 			bp->b_error = EIO;
504 			biodone(bp);
505 			return;
506 		}
507 	}
508 	s = splbio();
509 	BUFQ_PUT(&sc->sc_tab, bp);
510 	if (sc->sc_active == 0) {
511 		sc->sc_active = 1;
512 		mtustart(sc);
513 	}
514 	splx(s);
515 }
516 
517 static void
518 mtustart(struct mt_softc *sc)
519 {
520 
521 	dlog(LOG_DEBUG, "%s ustart", sc->sc_dev.dv_xname);
522 	if (hpibreq(sc->sc_dev.dv_parent, &sc->sc_hq))
523 		mtstart(sc);
524 }
525 
526 static void
527 spl_mtintr(void *arg)
528 {
529 	struct mt_softc *sc = arg;
530 	int s = splbio();
531 
532 	hpibppclear(sc->sc_hpibno);
533 	mtintr(sc);
534 	splx(s);
535 }
536 
537 static void
538 spl_mtstart(void *arg)
539 {
540 	int s = splbio();
541 
542 	mtstart(arg);
543 	splx(s);
544 }
545 
546 static void
547 mtstart(void *arg)
548 {
549 	struct mt_softc *sc = arg;
550 	struct buf *bp;
551 	short	cmdcount = 1;
552 	u_char	cmdbuf[2];
553 
554 	dlog(LOG_DEBUG, "%s start", sc->sc_dev.dv_xname);
555 	sc->sc_flags &= ~MTF_WRT;
556 	bp = BUFQ_PEEK(&sc->sc_tab);
557 	if ((sc->sc_flags & MTF_ALIVE) == 0 &&
558 	    ((bp->b_flags & B_CMD) == 0 || bp->b_cmd != MTRESET))
559 		goto fatalerror;
560 
561 	if (sc->sc_flags & MTF_REW) {
562 		if (!hpibpptest(sc->sc_hpibno, sc->sc_slave))
563 			goto stillrew;
564 		switch (mtreaddsj(sc, MTE_DSJ_FORCE|MTE_COMPLETE|MTE_IDLE)) {
565 		    case 0:
566 		    case 1:
567 		stillrew:
568 			if ((sc->sc_stat1 & SR1_BOT) ||
569 			    !(sc->sc_stat1 & SR1_ONLINE)) {
570 				sc->sc_flags &= ~MTF_REW;
571 				break;
572 			}
573 		    case -2:
574 			/*
575 			 * -2 means "timeout" reading DSJ, which is probably
576 			 * temporary.  This is considered OK when doing a NOP,
577 			 * but not otherwise.
578 			 */
579 			if (sc->sc_flags & (MTF_DSJTIMEO | MTF_STATTIMEO)) {
580 				callout_reset(&sc->sc_start_ch, hz >> 5,
581 				    spl_mtstart, sc);
582 				return;
583 			}
584 		    case 2:
585 			if (bp->b_cmd != MTNOP || !(bp->b_flags & B_CMD)) {
586 				bp->b_error = EBUSY;
587 				goto errdone;
588 			}
589 			goto done;
590 
591 		    default:
592 			goto fatalerror;
593 		}
594 	}
595 	if (bp->b_flags & B_CMD) {
596 		if (sc->sc_flags & MTF_PASTEOT) {
597 			switch(bp->b_cmd) {
598 			    case MTFSF:
599 			    case MTWEOF:
600 			    case MTFSR:
601 				bp->b_error = ENOSPC;
602 				goto errdone;
603 
604 			    case MTBSF:
605 			    case MTOFFL:
606 			    case MTBSR:
607 			    case MTREW:
608 				sc->sc_flags &= ~(MTF_PASTEOT | MTF_ATEOT);
609 				break;
610 			}
611 		}
612 		switch(bp->b_cmd) {
613 		    case MTFSF:
614 			if (sc->sc_flags & MTF_HITEOF)
615 				goto done;
616 			cmdbuf[0] = MTTC_FSF;
617 			break;
618 
619 		    case MTBSF:
620 			if (sc->sc_flags & MTF_HITBOF)
621 				goto done;
622 			cmdbuf[0] = MTTC_BSF;
623 			break;
624 
625 		    case MTOFFL:
626 			sc->sc_flags |= MTF_REW;
627 			cmdbuf[0] = MTTC_REWOFF;
628 			break;
629 
630 		    case MTWEOF:
631 			cmdbuf[0] = MTTC_WFM;
632 			break;
633 
634 		    case MTBSR:
635 			cmdbuf[0] = MTTC_BSR;
636 			break;
637 
638 		    case MTFSR:
639 			cmdbuf[0] = MTTC_FSR;
640 			break;
641 
642 		    case MTREW:
643 			sc->sc_flags |= MTF_REW;
644 			cmdbuf[0] = MTTC_REW;
645 			break;
646 
647 		    case MTNOP:
648 			/*
649 			 * NOP is supposed to set status bits.
650 			 * Force readdsj to do it.
651 			 */
652 			switch (mtreaddsj(sc,
653 			  MTE_DSJ_FORCE | MTE_COMPLETE | MTE_IDLE)) {
654 			    default:
655 				goto done;
656 
657 			    case -1:
658 				/*
659 				 * If this fails, perform a device clear
660 				 * to fix any protocol problems and (most
661 				 * likely) get the status.
662 				 */
663 				bp->b_cmd = MTRESET;
664 				break;
665 
666 			    case -2:
667 				callout_reset(&sc->sc_start_ch, hz >> 5,
668 				    spl_mtstart, sc);
669 				return;
670 			}
671 
672 		    case MTRESET:
673 			/*
674 			 * 1) selected device clear (send with "-2" secondary)
675 			 * 2) set timeout, then wait for "service request"
676 			 * 3) interrupt will read DSJ (and END COMPLETE-IDLE)
677 			 */
678 			if (hpibsend(sc->sc_hpibno, sc->sc_slave, -2, NULL, 0)){
679 				log(LOG_ERR, "%s can't reset",
680 				    sc->sc_dev.dv_xname);
681 				goto fatalerror;
682 			}
683 			callout_reset(&sc->sc_intr_ch, 4 * hz, spl_mtintr, sc);
684 			hpibawait(sc->sc_hpibno);
685 			return;
686 
687 		    case MTSET800BPI:
688 			cmdbuf[0] = MTTC_800;
689 			break;
690 
691 		    case MTSET1600BPI:
692 			cmdbuf[0] = MTTC_1600;
693 			break;
694 
695 		    case MTSET6250BPI:
696 			cmdbuf[0] = MTTC_6250;
697 			break;
698 
699 		    case MTSET6250DC:
700 			cmdbuf[0] = MTTC_DC6250;
701 			break;
702 		}
703 	} else {
704 		if (sc->sc_flags & MTF_PASTEOT) {
705 			bp->b_error = ENOSPC;
706 			goto errdone;
707 		}
708 		if (bp->b_flags & B_READ) {
709 			sc->sc_flags |= MTF_IO;
710 			cmdbuf[0] = MTTC_READ;
711 		} else {
712 			sc->sc_flags |= MTF_WRT | MTF_IO;
713 			cmdbuf[0] = MTTC_WRITE;
714 			cmdbuf[1] = (bp->b_bcount + ((1 << WRITE_BITS_IGNORED) - 1)) >> WRITE_BITS_IGNORED;
715 			cmdcount = 2;
716 		}
717 	}
718 	if (hpibsend(sc->sc_hpibno, sc->sc_slave, MTL_TCMD, cmdbuf, cmdcount)
719 	    == cmdcount) {
720 		if (sc->sc_flags & MTF_REW)
721 			goto done;
722 		hpibawait(sc->sc_hpibno);
723 		return;
724 	}
725 fatalerror:
726 	/*
727 	 * If anything fails, the drive is probably hosed, so mark it not
728 	 * "ALIVE" (but it EXISTS and is OPEN or we wouldn't be here, and
729 	 * if, last we heard, it was REWinding, remember that).
730 	 */
731 	sc->sc_flags &= MTF_EXISTS | MTF_OPEN | MTF_REW;
732 	bp->b_error = EIO;
733 errdone:
734 	bp->b_flags |= B_ERROR;
735 done:
736 	sc->sc_flags &= ~(MTF_HITEOF | MTF_HITBOF);
737 	(void)BUFQ_GET(&sc->sc_tab);
738 	biodone(bp);
739 	hpibfree(sc->sc_dev.dv_parent, &sc->sc_hq);
740 	if ((bp = BUFQ_PEEK(&sc->sc_tab)) == NULL)
741 		sc->sc_active = 0;
742 	else
743 		mtustart(sc);
744 }
745 
746 /*
747  * The Utah code had a bug which meant that the driver was unable to read.
748  * "rw" was initialized to bp->b_flags & B_READ before "bp" was initialized.
749  *   -- ajv@comp.vuw.ac.nz
750  */
751 static void
752 mtgo(void *arg)
753 {
754 	struct mt_softc *sc = arg;
755 	struct buf *bp;
756 	int rw;
757 
758 	dlog(LOG_DEBUG, "%s go", sc->sc_dev.dv_xname);
759 	bp = BUFQ_PEEK(&sc->sc_tab);
760 	rw = bp->b_flags & B_READ;
761 	hpibgo(sc->sc_hpibno, sc->sc_slave, rw ? MTT_READ : MTL_WRITE,
762 	    bp->b_data, bp->b_bcount, rw, rw != 0);
763 }
764 
765 static void
766 mtintr(void *arg)
767 {
768 	struct mt_softc *sc = arg;
769 	struct buf *bp;
770 	int i;
771 	u_char cmdbuf[4];
772 
773 	bp = BUFQ_PEEK(&sc->sc_tab);
774 	if (bp == NULL) {
775 		log(LOG_ERR, "%s intr: bp == NULL", sc->sc_dev.dv_xname);
776 		return;
777 	}
778 
779 	dlog(LOG_DEBUG, "%s intr", sc->sc_dev.dv_xname);
780 
781 	/*
782 	 * Some operation completed.  Read status bytes and report errors.
783 	 * Clear EOF flags here `cause they're set once on specific conditions
784 	 * below when a command succeeds.
785 	 * A DSJ of 2 always means keep waiting.  If the command was READ
786 	 * (and we're in data DMA phase) stop data transfer first.
787 	 */
788 	sc->sc_flags &= ~(MTF_HITEOF | MTF_HITBOF);
789 	if ((bp->b_flags & (B_CMD|B_READ)) == B_READ &&
790 	    !(sc->sc_flags & (MTF_IO | MTF_STATTIMEO | MTF_DSJTIMEO))){
791 		cmdbuf[0] = MTE_STOP;
792 		(void) hpibsend(sc->sc_hpibno, sc->sc_slave, MTL_ECMD,cmdbuf,1);
793 	}
794 	switch (mtreaddsj(sc, 0)) {
795 	    case 0:
796 		break;
797 
798 	    case 1:
799 		/*
800 		 * If we're in the middle of a READ/WRITE and have yet to
801 		 * start the data transfer, a DSJ of one should terminate it.
802 		 */
803 		sc->sc_flags &= ~MTF_IO;
804 		break;
805 
806 	    case 2:
807 		(void) hpibawait(sc->sc_hpibno);
808 		return;
809 
810 	    case -2:
811 		/*
812 		 * -2 means that the drive failed to respond quickly enough
813 		 * to the request for DSJ.  It's probably just "busy" figuring
814 		 * it out and will know in a little bit...
815 		 */
816 		callout_reset(&sc->sc_intr_ch, hz >> 5, spl_mtintr, sc);
817 		return;
818 
819 	    default:
820 		log(LOG_ERR, "%s intr: can't get drive stat",
821 		    sc->sc_dev.dv_xname);
822 		goto error;
823 	}
824 	if (sc->sc_stat1 & (SR1_ERR | SR1_REJECT)) {
825 		i = sc->sc_stat4 & SR4_ERCLMASK;
826 		log(LOG_ERR, "%s: %s error, retry %d, SR2/3 %x/%x, code %d",
827 			sc->sc_dev.dv_xname, i == SR4_DEVICE ? "device" :
828 			(i == SR4_PROTOCOL ? "protocol" :
829 			(i == SR4_SELFTEST ? "selftest" : "unknown")),
830 			sc->sc_stat4 & SR4_RETRYMASK, sc->sc_stat2,
831 			sc->sc_stat3, sc->sc_stat5);
832 
833 		if ((bp->b_flags & B_CMD) && bp->b_cmd == MTRESET)
834 			callout_stop(&sc->sc_intr_ch);
835 		if (sc->sc_stat3 & SR3_POWERUP)
836 			sc->sc_flags &= MTF_OPEN | MTF_EXISTS;
837 		goto error;
838 	}
839 	/*
840 	 * Report and clear any soft errors.
841 	 */
842 	if (sc->sc_stat1 & SR1_SOFTERR) {
843 		log(LOG_WARNING, "%s: soft error, retry %d\n",
844 			sc->sc_dev.dv_xname, sc->sc_stat4 & SR4_RETRYMASK);
845 		sc->sc_stat1 &= ~SR1_SOFTERR;
846 	}
847 	/*
848 	 * We've initiated a read or write, but haven't actually started to
849 	 * DMA the data yet.  At this point, the drive's ready.
850 	 */
851 	if (sc->sc_flags & MTF_IO) {
852 		sc->sc_flags &= ~MTF_IO;
853 		if (hpibustart(sc->sc_hpibno))
854 			mtgo(sc);
855 		return;
856 	}
857 	/*
858 	 * Check for End Of Tape - we're allowed to hit EOT and then write (or
859 	 * read) one more record.  If we get here and have not already hit EOT,
860 	 * return ENOSPC to inform the process that it's hit it.  If we get
861 	 * here and HAVE already hit EOT, don't allow any more operations that
862 	 * move the tape forward.
863 	 */
864 	if (sc->sc_stat1 & SR1_EOT) {
865 		if (sc->sc_flags & MTF_ATEOT)
866 			sc->sc_flags |= MTF_PASTEOT;
867 		else {
868 			bp->b_flags |= B_ERROR;
869 			bp->b_error = ENOSPC;
870 			sc->sc_flags |= MTF_ATEOT;
871 		}
872 	}
873 	/*
874 	 * If a motion command was being executed, check for Tape Marks.
875 	 * If we were doing data, make sure we got the right amount, and
876 	 * check for hitting tape marks on reads.
877 	 */
878 	if (bp->b_flags & B_CMD) {
879 		if (sc->sc_stat1 & SR1_EOF) {
880 			if (bp->b_cmd == MTFSR)
881 				sc->sc_flags |= MTF_HITEOF;
882 			if (bp->b_cmd == MTBSR)
883 				sc->sc_flags |= MTF_HITBOF;
884 		}
885 		if (bp->b_cmd == MTRESET) {
886 			callout_stop(&sc->sc_intr_ch);
887 			sc->sc_flags |= MTF_ALIVE;
888 		}
889 	} else {
890 		i = hpibrecv(sc->sc_hpibno, sc->sc_slave, MTT_BCNT, cmdbuf, 2);
891 		if (i != 2) {
892 			log(LOG_ERR, "%s intr: can't get xfer length\n",
893 			    sc->sc_dev.dv_xname);
894 			goto error;
895 		}
896 		i = (int) *((u_short *) cmdbuf);
897 		if (i <= bp->b_bcount) {
898 			if (i == 0)
899 				sc->sc_flags |= MTF_HITEOF;
900 			bp->b_resid = bp->b_bcount - i;
901 			dlog(LOG_DEBUG, "%s intr: bcount %ld, resid %ld",
902 			    sc->sc_dev.dv_xname, bp->b_bcount, bp->b_resid);
903 		} else {
904 			tprintf(sc->sc_ttyp,
905 				"%s: record (%d) larger than wanted (%ld)\n",
906 				sc->sc_dev.dv_xname, i, bp->b_bcount);
907     error:
908 			sc->sc_flags &= ~MTF_IO;
909 			bp->b_error = EIO;
910 			bp->b_flags |= B_ERROR;
911 		}
912 	}
913 	/*
914 	 * The operation is completely done.
915 	 * Let the drive know with an END command.
916 	 */
917 	cmdbuf[0] = MTE_COMPLETE | MTE_IDLE;
918 	(void) hpibsend(sc->sc_hpibno, sc->sc_slave, MTL_ECMD, cmdbuf, 1);
919 	bp->b_flags &= ~B_CMD;
920 	(void)BUFQ_GET(&sc->sc_tab);
921 	biodone(bp);
922 	hpibfree(sc->sc_dev.dv_parent, &sc->sc_hq);
923 	if (BUFQ_PEEK(&sc->sc_tab) == NULL)
924 		sc->sc_active = 0;
925 	else
926 		mtustart(sc);
927 }
928 
929 static int
930 mtread(dev_t dev, struct uio *uio, int flags)
931 {
932 	struct mt_softc *sc = mt_cd.cd_devs[UNIT(dev)];
933 
934 	return(physio(mtstrategy, &sc->sc_bufstore,
935 	    dev, B_READ, minphys, uio));
936 }
937 
938 static int
939 mtwrite(dev_t dev, struct uio *uio, int flags)
940 {
941 	struct mt_softc *sc = mt_cd.cd_devs[UNIT(dev)];
942 
943 	return(physio(mtstrategy, &sc->sc_bufstore,
944 	    dev, B_WRITE, minphys, uio));
945 }
946 
947 static int
948 mtioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
949 {
950 	struct mtop *op;
951 	int cnt;
952 
953 	switch (cmd) {
954 	    case MTIOCTOP:
955 		op = (struct mtop *)data;
956 		switch(op->mt_op) {
957 		    case MTWEOF:
958 		    case MTFSF:
959 		    case MTBSR:
960 		    case MTBSF:
961 		    case MTFSR:
962 			cnt = op->mt_count;
963 			break;
964 
965 		    case MTOFFL:
966 		    case MTREW:
967 		    case MTNOP:
968 			cnt = 0;
969 			break;
970 
971 		    default:
972 			return (EINVAL);
973 		}
974 		return (mtcommand(dev, op->mt_op, cnt));
975 
976 	    case MTIOCGET:
977 		break;
978 
979 	    default:
980 		return (EINVAL);
981 	}
982 	return (0);
983 }
984