xref: /netbsd-src/sys/arch/mac68k/dev/sbc.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f)
1 /*	$NetBSD: sbc.c,v 1.57 2018/09/03 16:29:25 riastradh Exp $	*/
2 
3 /*
4  * Copyright (C) 1996 Scott Reynolds.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /*
30  * This file contains only the machine-dependent parts of the mac68k
31  * NCR 5380 SCSI driver.  (Autoconfig stuff and PDMA functions.)
32  * The machine-independent parts are in ncr5380sbc.c
33  *
34  * Supported hardware includes:
35  * Macintosh II family 5380-based controller
36  *
37  * Credits, history:
38  *
39  * Scott Reynolds wrote this module, based on work by Allen Briggs
40  * (mac68k), Gordon W. Ross and David Jones (sun3), and Leo Weppelman
41  * (atari).  Thanks to Allen for supplying crucial interpretation of the
42  * NetBSD/mac68k 1.1 'ncrscsi' driver.  Also, Allen, Gordon, and Jason
43  * Thorpe all helped to refine this code, and were considerable sources
44  * of moral support.
45  */
46 
47 #include <sys/cdefs.h>
48 __KERNEL_RCSID(0, "$NetBSD: sbc.c,v 1.57 2018/09/03 16:29:25 riastradh Exp $");
49 
50 #include "opt_ddb.h"
51 
52 #include <sys/types.h>
53 #include <sys/param.h>
54 #include <sys/systm.h>
55 #include <sys/kernel.h>
56 #include <sys/errno.h>
57 #include <sys/device.h>
58 #include <sys/buf.h>
59 #include <sys/proc.h>
60 
61 #include <dev/scsipi/scsi_all.h>
62 #include <dev/scsipi/scsipi_all.h>
63 #include <dev/scsipi/scsipi_debug.h>
64 #include <dev/scsipi/scsiconf.h>
65 
66 #include <dev/ic/ncr5380reg.h>
67 #include <dev/ic/ncr5380var.h>
68 
69 #include <machine/cpu.h>
70 #include <machine/viareg.h>
71 
72 #include <mac68k/dev/sbcreg.h>
73 #include <mac68k/dev/sbcvar.h>
74 
75 /* SBC_DEBUG --  relies on DDB */
76 #ifdef SBC_DEBUG
77 # define	SBC_DB_INTR	0x01
78 # define	SBC_DB_DMA	0x02
79 # define	SBC_DB_REG	0x04
80 # define	SBC_DB_BREAK	0x08
81 # ifndef DDB
82 #  define	Debugger()	printf("Debug: sbc.c:%d\n", __LINE__)
83 # endif
84 # define	SBC_BREAK \
85 		do { if (sbc_debug & SBC_DB_BREAK) Debugger(); } while (0)
86 #else
87 # define	SBC_BREAK
88 #endif
89 
90 
91 int	sbc_debug = 0 /* | SBC_DB_INTR | SBC_DB_DMA */;
92 int	sbc_link_flags = 0 /* | SDEV_DB2 */;
93 int	sbc_options = 0 /* | SBC_PDMA */;
94 
95 extern label_t	*nofault;
96 extern void *	m68k_fault_addr;
97 
98 static	int	sbc_wait_busy(struct ncr5380_softc *);
99 static	int	sbc_ready(struct ncr5380_softc *);
100 static	int	sbc_wait_dreq(struct ncr5380_softc *);
101 
102 
103 /***
104  * General support for Mac-specific SCSI logic.
105  ***/
106 
107 /* These are used in the following inline functions. */
108 int sbc_wait_busy_timo = 1000 * 5000;	/* X2 = 10 S. */
109 int sbc_ready_timo = 1000 * 5000;	/* X2 = 10 S. */
110 int sbc_wait_dreq_timo = 1000 * 5000;	/* X2 = 10 S. */
111 
112 /* Return zero on success. */
113 static inline int
114 sbc_wait_busy(struct ncr5380_softc *sc)
115 {
116 	int timo = sbc_wait_busy_timo;
117 	for (;;) {
118 		if (SCI_BUSY(sc)) {
119 			timo = 0;	/* return 0 */
120 			break;
121 		}
122 		if (--timo < 0)
123 			break;	/* return -1 */
124 		delay(2);
125 	}
126 	return (timo);
127 }
128 
129 static inline int
130 sbc_ready(struct ncr5380_softc *sc)
131 {
132 	int timo = sbc_ready_timo;
133 
134 	for (;;) {
135 		if ((*sc->sci_csr & (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH))
136 		    == (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH)) {
137 			timo = 0;
138 			break;
139 		}
140 		if (((*sc->sci_csr & SCI_CSR_PHASE_MATCH) == 0)
141 		    || (SCI_BUSY(sc) == 0)) {
142 			timo = -1;
143 			break;
144 		}
145 		if (--timo < 0)
146 			break;	/* return -1 */
147 		delay(2);
148 	}
149 	return (timo);
150 }
151 
152 static inline int
153 sbc_wait_dreq(struct ncr5380_softc *sc)
154 {
155 	int timo = sbc_wait_dreq_timo;
156 
157 	for (;;) {
158 		if ((*sc->sci_csr & (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH))
159 		    == (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH)) {
160 			timo = 0;
161 			break;
162 		}
163 		if (--timo < 0)
164 			break;	/* return -1 */
165 		delay(2);
166 	}
167 	return (timo);
168 }
169 
170 void
171 sbc_irq_intr(void *p)
172 {
173 	struct ncr5380_softc *ncr_sc = p;
174 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
175 	int claimed = 0;
176 
177 	/* How we ever arrive here without IRQ set is a mystery... */
178 	if (*ncr_sc->sci_csr & SCI_CSR_INT) {
179 #ifdef SBC_DEBUG
180 		if (sbc_debug & SBC_DB_INTR)
181 			decode_5380_intr(ncr_sc);
182 #endif
183 		if (!cold)
184 			claimed = ncr5380_intr(ncr_sc);
185 		if (!claimed) {
186 			if (((*ncr_sc->sci_csr & ~SCI_CSR_PHASE_MATCH) == SCI_CSR_INT)
187 			    && ((*ncr_sc->sci_bus_csr & ~SCI_BUS_RST) == 0)) {
188 				SCI_CLR_INTR(ncr_sc);	/* RST interrupt */
189 				if (sc->sc_clrintr)
190 					(*sc->sc_clrintr)(ncr_sc);
191 			}
192 #ifdef SBC_DEBUG
193 			else {
194 				printf("%s: spurious intr\n",
195 				    device_xname(ncr_sc->sc_dev));
196 				SBC_BREAK;
197 			}
198 #endif
199 		}
200 	}
201 }
202 
203 #ifdef SBC_DEBUG
204 void
205 decode_5380_intr(struct ncr5380_softc *ncr_sc)
206 {
207 	u_int8_t csr = *ncr_sc->sci_csr;
208 	u_int8_t bus_csr = *ncr_sc->sci_bus_csr;
209 
210 	if (((csr & ~(SCI_CSR_PHASE_MATCH | SCI_CSR_ATN)) == SCI_CSR_INT) &&
211 	    ((bus_csr & ~(SCI_BUS_MSG | SCI_BUS_CD | SCI_BUS_IO | SCI_BUS_DBP)) == SCI_BUS_SEL)) {
212 		if (csr & SCI_BUS_IO)
213 			printf("%s: reselect\n", device_xname(ncr_sc->sc_dev));
214 		else
215 			printf("%s: select\n", device_xname(ncr_sc->sc_dev));
216 	} else if (((csr & ~SCI_CSR_ACK) == (SCI_CSR_DONE | SCI_CSR_INT)) &&
217 	    ((bus_csr & (SCI_BUS_RST | SCI_BUS_BSY | SCI_BUS_SEL)) == SCI_BUS_BSY))
218 		printf("%s: DMA eop\n", device_xname(ncr_sc->sc_dev));
219 	else if (((csr & ~SCI_CSR_PHASE_MATCH) == SCI_CSR_INT) &&
220 	    ((bus_csr & ~SCI_BUS_RST) == 0))
221 		printf("%s: bus reset\n", device_xname(ncr_sc->sc_dev));
222 	else if (((csr & ~(SCI_CSR_DREQ | SCI_CSR_ATN | SCI_CSR_ACK)) == (SCI_CSR_PERR | SCI_CSR_INT | SCI_CSR_PHASE_MATCH)) &&
223 	    ((bus_csr & (SCI_BUS_RST | SCI_BUS_BSY | SCI_BUS_SEL)) == SCI_BUS_BSY))
224 		printf("%s: parity error\n", device_xname(ncr_sc->sc_dev));
225 	else if (((csr & ~SCI_CSR_ATN) == SCI_CSR_INT) &&
226 	    ((bus_csr & (SCI_BUS_RST | SCI_BUS_BSY | SCI_BUS_REQ | SCI_BUS_SEL)) == (SCI_BUS_BSY | SCI_BUS_REQ)))
227 		printf("%s: phase mismatch\n", device_xname(ncr_sc->sc_dev));
228 	else if (((csr & ~SCI_CSR_PHASE_MATCH) == (SCI_CSR_INT | SCI_CSR_DISC)) &&
229 	    (bus_csr == 0))
230 		printf("%s: disconnect\n", device_xname(ncr_sc->sc_dev));
231 	else
232 		printf("%s: unknown intr: csr=%x, bus_csr=%x\n",
233 		    device_xname(ncr_sc->sc_dev), csr, bus_csr);
234 }
235 #endif
236 
237 
238 /***
239  * The following code implements polled PDMA.
240  ***/
241 
242 int
243 sbc_pdma_in(struct ncr5380_softc *ncr_sc, int phase, int datalen, u_char *data)
244 {
245 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
246 	volatile u_int32_t *long_data = (u_int32_t *)sc->sc_drq_addr;
247 	volatile u_int8_t *byte_data = (u_int8_t *)sc->sc_nodrq_addr;
248 	label_t faultbuf;
249 	int resid, s;
250 
251 	if (datalen < ncr_sc->sc_min_dma_len ||
252 	    (sc->sc_options & SBC_PDMA) == 0)
253 		return ncr5380_pio_in(ncr_sc, phase, datalen, data);
254 
255 	s = splbio();
256 	if (sbc_wait_busy(ncr_sc)) {
257 		splx(s);
258 		return 0;
259 	}
260 
261 	*ncr_sc->sci_mode |= SCI_MODE_DMA;
262 	*ncr_sc->sci_irecv = 0;
263 
264 	resid = datalen;
265 
266 	/*
267 	 * Setup for a possible bus error caused by SCSI controller
268 	 * switching out of DATA OUT before we're done with the
269 	 * current transfer.  (See comment before sbc_drq_intr().)
270 	 */
271 	nofault = &faultbuf;
272 	if (setjmp(nofault)) {
273 		goto interrupt;
274 	}
275 
276 #define R4	*(u_int32_t *)data = *long_data, data += 4;
277 	for (; resid >= 128; resid -= 128) {
278 		if (sbc_ready(ncr_sc))
279 			goto interrupt;
280 		R4; R4; R4; R4; R4; R4; R4; R4;
281 		R4; R4; R4; R4; R4; R4; R4; R4;
282 		R4; R4; R4; R4; R4; R4; R4; R4;
283 		R4; R4; R4; R4; R4; R4; R4; R4;		/* 128 */
284 	}
285 	while (resid) {
286 		if (sbc_ready(ncr_sc))
287 			goto interrupt;
288 		*(u_int8_t *)data = *byte_data, data += 1;
289 		resid--;
290 	}
291 #undef R4
292 
293 interrupt:
294 	nofault = NULL;
295 	SCI_CLR_INTR(ncr_sc);
296 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
297 	*ncr_sc->sci_icmd = 0;
298 	splx(s);
299 	return (datalen - resid);
300 }
301 
302 int
303 sbc_pdma_out(struct ncr5380_softc *ncr_sc, int phase, int datalen, u_char *data)
304 {
305 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
306 	volatile u_int32_t *long_data = (u_int32_t *)sc->sc_drq_addr;
307 	volatile u_int8_t *byte_data = (u_int8_t *)sc->sc_nodrq_addr;
308 	label_t faultbuf;
309 	int resid, s;
310 	u_int8_t icmd;
311 
312 #if 1
313 	/* Work around lame gcc initialization bug */
314 	(void)&data;
315 #endif
316 
317 	if (datalen < ncr_sc->sc_min_dma_len ||
318 	    (sc->sc_options & SBC_PDMA) == 0)
319 		return ncr5380_pio_out(ncr_sc, phase, datalen, data);
320 
321 	s = splbio();
322 	if (sbc_wait_busy(ncr_sc)) {
323 		splx(s);
324 		return 0;
325 	}
326 
327 	icmd = *(ncr_sc->sci_icmd) & SCI_ICMD_RMASK;
328 	*ncr_sc->sci_icmd = icmd | SCI_ICMD_DATA;
329 	*ncr_sc->sci_mode |= SCI_MODE_DMA;
330 	*ncr_sc->sci_dma_send = 0;
331 
332 	/*
333 	 * Setup for a possible bus error caused by SCSI controller
334 	 * switching out of DATA OUT before we're done with the
335 	 * current transfer.  (See comment before sbc_drq_intr().)
336 	 */
337 	nofault = &faultbuf;
338 
339 	if (setjmp(nofault)) {
340 		printf("buf = 0x%lx, fault = 0x%lx\n",
341 		    (u_long)sc->sc_drq_addr, (u_long)m68k_fault_addr);
342 		panic("Unexpected bus error in sbc_pdma_out()");
343 	}
344 
345 #define W1	*byte_data = *(u_int8_t *)data, data += 1
346 #define W4	*long_data = *(u_int32_t *)data, data += 4
347 	for (resid = datalen; resid >= 64; resid -= 64) {
348 		if (sbc_ready(ncr_sc))
349 			goto interrupt;
350 		W1;
351 		if (sbc_ready(ncr_sc))
352 			goto interrupt;
353 		W1;
354 		if (sbc_ready(ncr_sc))
355 			goto interrupt;
356 		W1;
357 		if (sbc_ready(ncr_sc))
358 			goto interrupt;
359 		W1;
360 		if (sbc_ready(ncr_sc))
361 			goto interrupt;
362 		W4; W4; W4; W4;
363 		W4; W4; W4; W4;
364 		W4; W4; W4; W4;
365 		W4; W4; W4;
366 	}
367 	while (resid) {
368 		if (sbc_ready(ncr_sc))
369 			goto interrupt;
370 		W1;
371 		resid--;
372 	}
373 #undef  W1
374 #undef  W4
375 	if (sbc_wait_dreq(ncr_sc))
376 		printf("%s: timeout waiting for DREQ.\n",
377 		    device_xname(ncr_sc->sc_dev));
378 
379 	*byte_data = 0;
380 	goto done;
381 
382 interrupt:
383 	if ((*ncr_sc->sci_csr & SCI_CSR_PHASE_MATCH) == 0) {
384 		*ncr_sc->sci_icmd = icmd & ~SCI_ICMD_DATA;
385 		--resid;
386 	}
387 
388 done:
389 	SCI_CLR_INTR(ncr_sc);
390 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
391 	*ncr_sc->sci_icmd = icmd;
392 	splx(s);
393 	return (datalen - resid);
394 }
395 
396 
397 /***
398  * The following code implements interrupt-driven PDMA.
399  ***/
400 
401 /*
402  * This is the meat of the PDMA transfer.
403  * When we get here, we shove data as fast as the mac can take it.
404  * We depend on several things:
405  *   * All macs after the Mac Plus that have a 5380 chip should have a general
406  *     logic IC that handshakes data for blind transfers.
407  *   * If the SCSI controller finishes sending/receiving data before we do,
408  *     the same general logic IC will generate a /BERR for us in short order.
409  *   * The fault address for said /BERR minus the base address for the
410  *     transfer will be the amount of data that was actually written.
411  *
412  * We use the nofault flag and the setjmp/longjmp in locore.s so we can
413  * detect and handle the bus error for early termination of a command.
414  * This is usually caused by a disconnecting target.
415  */
416 void
417 sbc_drq_intr(void *p)
418 {
419 	struct sbc_softc *sc = (struct sbc_softc *)p;
420 	struct ncr5380_softc *ncr_sc = (struct ncr5380_softc *)p;
421 	struct sci_req *sr = ncr_sc->sc_current;
422 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
423 	label_t faultbuf;
424 	volatile u_int32_t *long_drq;
425 	u_int32_t *long_data;
426 	volatile u_int8_t *drq = 0;	/* XXX gcc4 -Wuninitialized */
427 	u_int8_t *data;
428 	int count, dcount, resid;
429 
430 	/*
431 	 * If we're not ready to xfer data, or have no more, just return.
432 	 */
433 	if ((*ncr_sc->sci_csr & SCI_CSR_DREQ) == 0 || dh->dh_len == 0)
434 		return;
435 
436 #ifdef SBC_DEBUG
437 	if (sbc_debug & SBC_DB_INTR)
438 		printf("%s: drq intr, dh_len=0x%x, dh_flags=0x%x\n",
439 		    device_xname(ncr_sc->sc_dev), dh->dh_len, dh->dh_flags);
440 #endif
441 
442 	/*
443 	 * Setup for a possible bus error caused by SCSI controller
444 	 * switching out of DATA-IN/OUT before we're done with the
445 	 * current transfer.
446 	 */
447 	nofault = &faultbuf;
448 
449 	if (setjmp(nofault)) {
450 		nofault = (label_t *)0;
451 		if ((dh->dh_flags & SBC_DH_DONE) == 0) {
452 			count = ((  (u_long)m68k_fault_addr
453 				  - (u_long)sc->sc_drq_addr));
454 
455 			if ((count < 0) || (count > dh->dh_len)) {
456 				printf("%s: complete=0x%x (pending 0x%x)\n",
457 				    device_xname(ncr_sc->sc_dev), count,
458 				    dh->dh_len);
459 				panic("something is wrong");
460 			}
461 
462 			dh->dh_addr += count;
463 			dh->dh_len -= count;
464 		} else
465 			count = 0;
466 
467 #ifdef SBC_DEBUG
468 		if (sbc_debug & SBC_DB_INTR)
469 			printf("%s: drq /berr, complete=0x%x (pending 0x%x)\n",
470 			   device_xname(ncr_sc->sc_dev), count, dh->dh_len);
471 #endif
472 		m68k_fault_addr = 0;
473 
474 		return;
475 	}
476 
477 	if (dh->dh_flags & SBC_DH_OUT) { /* Data Out */
478 		dcount = 0;
479 
480 		/*
481 		 * Get the source address aligned.
482 		 */
483 		resid =
484 		    count = uimin(dh->dh_len, 4 - (((int)dh->dh_addr) & 0x3));
485 		if (count && count < 4) {
486 			drq = (volatile u_int8_t *)sc->sc_drq_addr;
487 			data = (u_int8_t *)dh->dh_addr;
488 
489 #define W1		*drq++ = *data++
490 			while (count) {
491 				W1; count--;
492 			}
493 #undef W1
494 			dh->dh_addr += resid;
495 			dh->dh_len -= resid;
496 		}
497 
498 		/*
499 		 * Start the transfer.
500 		 */
501 		while (dh->dh_len) {
502 			dcount = count = uimin(dh->dh_len, MAX_DMA_LEN);
503 			long_drq = (volatile u_int32_t *)sc->sc_drq_addr;
504 			long_data = (u_int32_t *)dh->dh_addr;
505 
506 #define W4		*long_drq++ = *long_data++
507 			while (count >= 64) {
508 				W4; W4; W4; W4; W4; W4; W4; W4;
509 				W4; W4; W4; W4; W4; W4; W4; W4; /*  64 */
510 				count -= 64;
511 			}
512 			while (count >= 4) {
513 				W4; count -= 4;
514 			}
515 #undef W4
516 			data = (u_int8_t *)long_data;
517 			drq = (volatile u_int8_t *)long_drq;
518 
519 #define W1		*drq++ = *data++
520 			while (count) {
521 				W1; count--;
522 			}
523 #undef W1
524 			dh->dh_len -= dcount;
525 			dh->dh_addr += dcount;
526 		}
527 		dh->dh_flags |= SBC_DH_DONE;
528 
529 		/*
530 		 * XXX -- Read a byte from the SBC to trigger a /BERR.
531 		 * This seems to be necessary for us to notice that
532 		 * the target has disconnected.  Ick.  06 jun 1996 (sr)
533 		 */
534 		if (dcount >= MAX_DMA_LEN)
535 			drq = (volatile u_int8_t *)sc->sc_drq_addr;
536 		(void)*drq;
537 	} else {	/* Data In */
538 		/*
539 		 * Get the dest address aligned.
540 		 */
541 		resid =
542 		    count = uimin(dh->dh_len, 4 - (((int)dh->dh_addr) & 0x3));
543 		if (count && count < 4) {
544 			data = (u_int8_t *)dh->dh_addr;
545 			drq = (volatile u_int8_t *)sc->sc_drq_addr;
546 			while (count) {
547 				*data++ = *drq++;
548 				count--;
549 			}
550 			dh->dh_addr += resid;
551 			dh->dh_len -= resid;
552 		}
553 
554 		/*
555 		 * Start the transfer.
556 		 */
557 		while (dh->dh_len) {
558 			dcount = count = uimin(dh->dh_len, MAX_DMA_LEN);
559 			long_data = (u_int32_t *)dh->dh_addr;
560 			long_drq = (volatile u_int32_t *)sc->sc_drq_addr;
561 
562 #define R4		*long_data++ = *long_drq++
563 			while (count >= 64) {
564 				R4; R4; R4; R4; R4; R4; R4; R4;
565 				R4; R4; R4; R4; R4; R4; R4; R4;	/* 64 */
566 				count -= 64;
567 			}
568 			while (count >= 4) {
569 				R4; count -= 4;
570 			}
571 #undef R4
572 			data = (u_int8_t *)long_data;
573 			drq = (volatile u_int8_t *)long_drq;
574 			while (count) {
575 				*data++ = *drq++;
576 				count--;
577 			}
578 			dh->dh_len -= dcount;
579 			dh->dh_addr += dcount;
580 		}
581 		dh->dh_flags |= SBC_DH_DONE;
582 	}
583 
584 	/*
585 	 * OK.  No bus error occurred above.  Clear the nofault flag
586 	 * so we no longer short-circuit bus errors.
587 	 */
588 	nofault = (label_t *)0;
589 
590 #ifdef SBC_DEBUG
591 	if (sbc_debug & (SBC_DB_REG | SBC_DB_INTR))
592 		printf("%s: drq intr complete: csr=0x%x, bus_csr=0x%x\n",
593 		    device_xname(ncr_sc->sc_dev), *ncr_sc->sci_csr,
594 		    *ncr_sc->sci_bus_csr);
595 #endif
596 }
597 
598 void
599 sbc_dma_alloc(struct ncr5380_softc *ncr_sc)
600 {
601 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
602 	struct sci_req *sr = ncr_sc->sc_current;
603 	struct scsipi_xfer *xs = sr->sr_xs;
604 	struct sbc_pdma_handle *dh;
605 	int		i, xlen;
606 
607 #ifdef DIAGNOSTIC
608 	if (sr->sr_dma_hand != NULL)
609 		panic("sbc_dma_alloc: already have PDMA handle");
610 #endif
611 
612 	/* Polled transfers shouldn't allocate a PDMA handle. */
613 	if (sr->sr_flags & SR_IMMED)
614 		return;
615 
616 	xlen = ncr_sc->sc_datalen;
617 
618 	/* Make sure our caller checked sc_min_dma_len. */
619 	if (xlen < MIN_DMA_LEN)
620 		panic("sbc_dma_alloc: len=0x%x", xlen);
621 
622 	/*
623 	 * Find free PDMA handle.  Guaranteed to find one since we
624 	 * have as many PDMA handles as the driver has processes.
625 	 * (instances?)
626 	 */
627 	 for (i = 0; i < SCI_OPENINGS; i++) {
628 		if ((sc->sc_pdma[i].dh_flags & SBC_DH_BUSY) == 0)
629 			goto found;
630 	}
631 	panic("sbc: no free PDMA handles");
632 found:
633 	dh = &sc->sc_pdma[i];
634 	dh->dh_flags = SBC_DH_BUSY;
635 	dh->dh_addr = ncr_sc->sc_dataptr;
636 	dh->dh_len = xlen;
637 
638 	/* Copy the 'write' flag for convenience. */
639 	if (xs->xs_control & XS_CTL_DATA_OUT)
640 		dh->dh_flags |= SBC_DH_OUT;
641 
642 	sr->sr_dma_hand = dh;
643 }
644 
645 void
646 sbc_dma_free(struct ncr5380_softc *ncr_sc)
647 {
648 	struct sci_req *sr = ncr_sc->sc_current;
649 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
650 
651 #ifdef DIAGNOSTIC
652 	if (sr->sr_dma_hand == NULL)
653 		panic("sbc_dma_free: no DMA handle");
654 #endif
655 
656 	if (ncr_sc->sc_state & NCR_DOINGDMA)
657 		panic("sbc_dma_free: free while in progress");
658 
659 	if (dh->dh_flags & SBC_DH_BUSY) {
660 		dh->dh_flags = 0;
661 		dh->dh_addr = NULL;
662 		dh->dh_len = 0;
663 	}
664 	sr->sr_dma_hand = NULL;
665 }
666 
667 void
668 sbc_dma_poll(struct ncr5380_softc *ncr_sc)
669 {
670 	struct sci_req *sr = ncr_sc->sc_current;
671 
672 	/*
673 	 * We shouldn't arrive here; if SR_IMMED is set, then
674 	 * dma_alloc() should have refused to allocate a handle
675 	 * for the transfer.  This forces the polled PDMA code
676 	 * to handle the request...
677 	 */
678 #ifdef SBC_DEBUG
679 	if (sbc_debug & SBC_DB_DMA)
680 		printf("%s: lost DRQ interrupt?\n",
681 		    device_xname(ncr_sc->sc_dev));
682 #endif
683 	sr->sr_flags |= SR_OVERDUE;
684 }
685 
686 void
687 sbc_dma_setup(struct ncr5380_softc *ncr_sc)
688 {
689 	/* Not needed; we don't have real DMA */
690 }
691 
692 void
693 sbc_dma_start(struct ncr5380_softc *ncr_sc)
694 {
695 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
696 	struct sci_req *sr = ncr_sc->sc_current;
697 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
698 
699 	/*
700 	 * Match bus phase, clear pending interrupts, set DMA mode, and
701 	 * assert data bus (for writing only), then start the transfer.
702 	 */
703 	if (dh->dh_flags & SBC_DH_OUT) {
704 		*ncr_sc->sci_tcmd = PHASE_DATA_OUT;
705 		SCI_CLR_INTR(ncr_sc);
706 		if (sc->sc_clrintr)
707 			(*sc->sc_clrintr)(ncr_sc);
708 		*ncr_sc->sci_mode |= SCI_MODE_DMA;
709 		*ncr_sc->sci_icmd = SCI_ICMD_DATA;
710 		*ncr_sc->sci_dma_send = 0;
711 	} else {
712 		*ncr_sc->sci_tcmd = PHASE_DATA_IN;
713 		SCI_CLR_INTR(ncr_sc);
714 		if (sc->sc_clrintr)
715 			(*sc->sc_clrintr)(ncr_sc);
716 		*ncr_sc->sci_mode |= SCI_MODE_DMA;
717 		*ncr_sc->sci_icmd = 0;
718 		*ncr_sc->sci_irecv = 0;
719 	}
720 	ncr_sc->sc_state |= NCR_DOINGDMA;
721 
722 #ifdef SBC_DEBUG
723 	if (sbc_debug & SBC_DB_DMA)
724 		printf("%s: PDMA started, va=%p, len=0x%x\n",
725 		    device_xname(ncr_sc->sc_dev), dh->dh_addr, dh->dh_len);
726 #endif
727 }
728 
729 void
730 sbc_dma_eop(struct ncr5380_softc *ncr_sc)
731 {
732 	/* Not used; the EOP pin is wired high (GMFH, pp. 389-390) */
733 }
734 
735 void
736 sbc_dma_stop(struct ncr5380_softc *ncr_sc)
737 {
738 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
739 	struct sci_req *sr = ncr_sc->sc_current;
740 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
741 	int ntrans;
742 
743 	if ((ncr_sc->sc_state & NCR_DOINGDMA) == 0) {
744 #ifdef SBC_DEBUG
745 		if (sbc_debug & SBC_DB_DMA)
746 			printf("%s: dma_stop: DMA not running\n",
747 			    device_xname(ncr_sc->sc_dev));
748 #endif
749 		return;
750 	}
751 	ncr_sc->sc_state &= ~NCR_DOINGDMA;
752 
753 	if ((ncr_sc->sc_state & NCR_ABORTING) == 0) {
754 		ntrans = ncr_sc->sc_datalen - dh->dh_len;
755 
756 #ifdef SBC_DEBUG
757 		if (sbc_debug & SBC_DB_DMA)
758 			printf("%s: dma_stop: ntrans=0x%x\n",
759 			    device_xname(ncr_sc->sc_dev), ntrans);
760 #endif
761 
762 		if (ntrans > ncr_sc->sc_datalen)
763 			panic("sbc_dma_stop: excess transfer");
764 
765 		/* Adjust data pointer */
766 		ncr_sc->sc_dataptr += ntrans;
767 		ncr_sc->sc_datalen -= ntrans;
768 
769 		/* Clear any pending interrupts. */
770 		SCI_CLR_INTR(ncr_sc);
771 		if (sc->sc_clrintr)
772 			(*sc->sc_clrintr)(ncr_sc);
773 	}
774 
775 	/* Put SBIC back into PIO mode. */
776 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
777 	*ncr_sc->sci_icmd = 0;
778 
779 #ifdef SBC_DEBUG
780 	if (sbc_debug & SBC_DB_REG)
781 		printf("%s: dma_stop: csr=0x%x, bus_csr=0x%x\n",
782 		    device_xname(ncr_sc->sc_dev), *ncr_sc->sci_csr,
783 		    *ncr_sc->sci_bus_csr);
784 #endif
785 }
786