xref: /netbsd-src/sys/arch/mac68k/dev/sbc.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /*	$NetBSD: sbc.c,v 1.52 2007/03/04 06:00:07 christos 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 1.52 2007/03/04 06:00:07 christos 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 #include <sys/user.h>
61 
62 #include <dev/scsipi/scsi_all.h>
63 #include <dev/scsipi/scsipi_all.h>
64 #include <dev/scsipi/scsipi_debug.h>
65 #include <dev/scsipi/scsiconf.h>
66 
67 #include <dev/ic/ncr5380reg.h>
68 #include <dev/ic/ncr5380var.h>
69 
70 #include <machine/cpu.h>
71 #include <machine/viareg.h>
72 
73 #include <mac68k/dev/sbcreg.h>
74 #include <mac68k/dev/sbcvar.h>
75 
76 /* SBC_DEBUG --  relies on DDB */
77 #ifdef SBC_DEBUG
78 # define	SBC_DB_INTR	0x01
79 # define	SBC_DB_DMA	0x02
80 # define	SBC_DB_REG	0x04
81 # define	SBC_DB_BREAK	0x08
82 # ifndef DDB
83 #  define	Debugger()	printf("Debug: sbc.c:%d\n", __LINE__)
84 # endif
85 # define	SBC_BREAK \
86 		do { if (sbc_debug & SBC_DB_BREAK) Debugger(); } while (0)
87 #else
88 # define	SBC_BREAK
89 #endif
90 
91 
92 int	sbc_debug = 0 /* | SBC_DB_INTR | SBC_DB_DMA */;
93 int	sbc_link_flags = 0 /* | SDEV_DB2 */;
94 int	sbc_options = 0 /* | SBC_PDMA */;
95 
96 extern label_t	*nofault;
97 extern void *	m68k_fault_addr;
98 
99 static	int	sbc_wait_busy(struct ncr5380_softc *);
100 static	int	sbc_ready(struct ncr5380_softc *);
101 static	int	sbc_wait_dreq(struct ncr5380_softc *);
102 
103 
104 /***
105  * General support for Mac-specific SCSI logic.
106  ***/
107 
108 /* These are used in the following inline functions. */
109 int sbc_wait_busy_timo = 1000 * 5000;	/* X2 = 10 S. */
110 int sbc_ready_timo = 1000 * 5000;	/* X2 = 10 S. */
111 int sbc_wait_dreq_timo = 1000 * 5000;	/* X2 = 10 S. */
112 
113 /* Return zero on success. */
114 static inline int
115 sbc_wait_busy(struct ncr5380_softc *sc)
116 {
117 	int timo = sbc_wait_busy_timo;
118 	for (;;) {
119 		if (SCI_BUSY(sc)) {
120 			timo = 0;	/* return 0 */
121 			break;
122 		}
123 		if (--timo < 0)
124 			break;	/* return -1 */
125 		delay(2);
126 	}
127 	return (timo);
128 }
129 
130 static inline int
131 sbc_ready(struct ncr5380_softc *sc)
132 {
133 	int timo = sbc_ready_timo;
134 
135 	for (;;) {
136 		if ((*sc->sci_csr & (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH))
137 		    == (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH)) {
138 			timo = 0;
139 			break;
140 		}
141 		if (((*sc->sci_csr & SCI_CSR_PHASE_MATCH) == 0)
142 		    || (SCI_BUSY(sc) == 0)) {
143 			timo = -1;
144 			break;
145 		}
146 		if (--timo < 0)
147 			break;	/* return -1 */
148 		delay(2);
149 	}
150 	return (timo);
151 }
152 
153 static inline int
154 sbc_wait_dreq(struct ncr5380_softc *sc)
155 {
156 	int timo = sbc_wait_dreq_timo;
157 
158 	for (;;) {
159 		if ((*sc->sci_csr & (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH))
160 		    == (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH)) {
161 			timo = 0;
162 			break;
163 		}
164 		if (--timo < 0)
165 			break;	/* return -1 */
166 		delay(2);
167 	}
168 	return (timo);
169 }
170 
171 void
172 sbc_irq_intr(void *p)
173 {
174 	struct ncr5380_softc *ncr_sc = p;
175 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
176 	int claimed = 0;
177 
178 	/* How we ever arrive here without IRQ set is a mystery... */
179 	if (*ncr_sc->sci_csr & SCI_CSR_INT) {
180 #ifdef SBC_DEBUG
181 		if (sbc_debug & SBC_DB_INTR)
182 			decode_5380_intr(ncr_sc);
183 #endif
184 		if (!cold)
185 			claimed = ncr5380_intr(ncr_sc);
186 		if (!claimed) {
187 			if (((*ncr_sc->sci_csr & ~SCI_CSR_PHASE_MATCH) == SCI_CSR_INT)
188 			    && ((*ncr_sc->sci_bus_csr & ~SCI_BUS_RST) == 0)) {
189 				SCI_CLR_INTR(ncr_sc);	/* RST interrupt */
190 				if (sc->sc_clrintr)
191 					(*sc->sc_clrintr)(ncr_sc);
192 			}
193 #ifdef SBC_DEBUG
194 			else {
195 				printf("%s: spurious intr\n",
196 				    ncr_sc->sc_dev.dv_xname);
197 				SBC_BREAK;
198 			}
199 #endif
200 		}
201 	}
202 }
203 
204 #ifdef SBC_DEBUG
205 void
206 decode_5380_intr(struct ncr5380_softc *ncr_sc)
207 {
208 	u_int8_t csr = *ncr_sc->sci_csr;
209 	u_int8_t bus_csr = *ncr_sc->sci_bus_csr;
210 
211 	if (((csr & ~(SCI_CSR_PHASE_MATCH | SCI_CSR_ATN)) == SCI_CSR_INT) &&
212 	    ((bus_csr & ~(SCI_BUS_MSG | SCI_BUS_CD | SCI_BUS_IO | SCI_BUS_DBP)) == SCI_BUS_SEL)) {
213 		if (csr & SCI_BUS_IO)
214 			printf("%s: reselect\n", ncr_sc->sc_dev.dv_xname);
215 		else
216 			printf("%s: select\n", ncr_sc->sc_dev.dv_xname);
217 	} else if (((csr & ~SCI_CSR_ACK) == (SCI_CSR_DONE | SCI_CSR_INT)) &&
218 	    ((bus_csr & (SCI_BUS_RST | SCI_BUS_BSY | SCI_BUS_SEL)) == SCI_BUS_BSY))
219 		printf("%s: DMA eop\n", ncr_sc->sc_dev.dv_xname);
220 	else if (((csr & ~SCI_CSR_PHASE_MATCH) == SCI_CSR_INT) &&
221 	    ((bus_csr & ~SCI_BUS_RST) == 0))
222 		printf("%s: bus reset\n", ncr_sc->sc_dev.dv_xname);
223 	else if (((csr & ~(SCI_CSR_DREQ | SCI_CSR_ATN | SCI_CSR_ACK)) == (SCI_CSR_PERR | SCI_CSR_INT | SCI_CSR_PHASE_MATCH)) &&
224 	    ((bus_csr & (SCI_BUS_RST | SCI_BUS_BSY | SCI_BUS_SEL)) == SCI_BUS_BSY))
225 		printf("%s: parity error\n", ncr_sc->sc_dev.dv_xname);
226 	else if (((csr & ~SCI_CSR_ATN) == SCI_CSR_INT) &&
227 	    ((bus_csr & (SCI_BUS_RST | SCI_BUS_BSY | SCI_BUS_REQ | SCI_BUS_SEL)) == (SCI_BUS_BSY | SCI_BUS_REQ)))
228 		printf("%s: phase mismatch\n", ncr_sc->sc_dev.dv_xname);
229 	else if (((csr & ~SCI_CSR_PHASE_MATCH) == (SCI_CSR_INT | SCI_CSR_DISC)) &&
230 	    (bus_csr == 0))
231 		printf("%s: disconnect\n", ncr_sc->sc_dev.dv_xname);
232 	else
233 		printf("%s: unknown intr: csr=%x, bus_csr=%x\n",
234 		    ncr_sc->sc_dev.dv_xname, csr, bus_csr);
235 }
236 #endif
237 
238 
239 /***
240  * The following code implements polled PDMA.
241  ***/
242 
243 int
244 sbc_pdma_in(struct ncr5380_softc *ncr_sc, int phase, int datalen, u_char *data)
245 {
246 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
247 	volatile u_int32_t *long_data = (u_int32_t *)sc->sc_drq_addr;
248 	volatile u_int8_t *byte_data = (u_int8_t *)sc->sc_nodrq_addr;
249 	label_t faultbuf;
250 	int resid, s;
251 
252 	if (datalen < ncr_sc->sc_min_dma_len ||
253 	    (sc->sc_options & SBC_PDMA) == 0)
254 		return ncr5380_pio_in(ncr_sc, phase, datalen, data);
255 
256 	s = splbio();
257 	if (sbc_wait_busy(ncr_sc)) {
258 		splx(s);
259 		return 0;
260 	}
261 
262 	*ncr_sc->sci_mode |= SCI_MODE_DMA;
263 	*ncr_sc->sci_irecv = 0;
264 
265 	resid = datalen;
266 
267 	/*
268 	 * Setup for a possible bus error caused by SCSI controller
269 	 * switching out of DATA OUT before we're done with the
270 	 * current transfer.  (See comment before sbc_drq_intr().)
271 	 */
272 	nofault = &faultbuf;
273 	if (setjmp(nofault)) {
274 		goto interrupt;
275 	}
276 
277 #define R4	*(u_int32_t *)data = *long_data, data += 4;
278 #define R1	*(u_int8_t *)data = *byte_data, data += 1;
279 	for (; resid >= 128; resid -= 128) {
280 		if (sbc_ready(ncr_sc))
281 			goto interrupt;
282 		R4; R4; R4; R4; R4; R4; R4; R4;
283 		R4; R4; R4; R4; R4; R4; R4; R4;
284 		R4; R4; R4; R4; R4; R4; R4; R4;
285 		R4; R4; R4; R4; R4; R4; R4; R4;		/* 128 */
286 	}
287 	while (resid) {
288 		if (sbc_ready(ncr_sc))
289 			goto interrupt;
290 		R1;
291 		resid--;
292 	}
293 #undef R4
294 #undef R1
295 
296 interrupt:
297 	nofault = NULL;
298 	SCI_CLR_INTR(ncr_sc);
299 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
300 	*ncr_sc->sci_icmd = 0;
301 	splx(s);
302 	return (datalen - resid);
303 }
304 
305 int
306 sbc_pdma_out(struct ncr5380_softc *ncr_sc, int phase, int datalen, u_char *data)
307 {
308 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
309 	volatile u_int32_t *long_data = (u_int32_t *)sc->sc_drq_addr;
310 	volatile u_int8_t *byte_data = (u_int8_t *)sc->sc_nodrq_addr;
311 	label_t faultbuf;
312 	int resid, s;
313 	u_int8_t icmd;
314 
315 #if 1
316 	/* Work around lame gcc initialization bug */
317 	(void)&data;
318 #endif
319 
320 	if (datalen < ncr_sc->sc_min_dma_len ||
321 	    (sc->sc_options & SBC_PDMA) == 0)
322 		return ncr5380_pio_out(ncr_sc, phase, datalen, data);
323 
324 	s = splbio();
325 	if (sbc_wait_busy(ncr_sc)) {
326 		splx(s);
327 		return 0;
328 	}
329 
330 	icmd = *(ncr_sc->sci_icmd) & SCI_ICMD_RMASK;
331 	*ncr_sc->sci_icmd = icmd | SCI_ICMD_DATA;
332 	*ncr_sc->sci_mode |= SCI_MODE_DMA;
333 	*ncr_sc->sci_dma_send = 0;
334 
335 	/*
336 	 * Setup for a possible bus error caused by SCSI controller
337 	 * switching out of DATA OUT before we're done with the
338 	 * current transfer.  (See comment before sbc_drq_intr().)
339 	 */
340 	nofault = &faultbuf;
341 
342 	if (setjmp(nofault)) {
343 		printf("buf = 0x%lx, fault = 0x%lx\n",
344 		    (u_long)sc->sc_drq_addr, (u_long)m68k_fault_addr);
345 		panic("Unexpected bus error in sbc_pdma_out()");
346 	}
347 
348 #define W1	*byte_data = *(u_int8_t *)data, data += 1
349 #define W4	*long_data = *(u_int32_t *)data, data += 4
350 	for (resid = datalen; resid >= 64; resid -= 64) {
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 		W1;
363 		if (sbc_ready(ncr_sc))
364 			goto interrupt;
365 		W4; W4; W4; W4;
366 		W4; W4; W4; W4;
367 		W4; W4; W4; W4;
368 		W4; W4; W4;
369 	}
370 	while (resid) {
371 		if (sbc_ready(ncr_sc))
372 			goto interrupt;
373 		W1;
374 		resid--;
375 	}
376 #undef  W1
377 #undef  W4
378 	if (sbc_wait_dreq(ncr_sc))
379 		printf("%s: timeout waiting for DREQ.\n",
380 		    ncr_sc->sc_dev.dv_xname);
381 
382 	*byte_data = 0;
383 	goto done;
384 
385 interrupt:
386 	if ((*ncr_sc->sci_csr & SCI_CSR_PHASE_MATCH) == 0) {
387 		*ncr_sc->sci_icmd = icmd & ~SCI_ICMD_DATA;
388 		--resid;
389 	}
390 
391 done:
392 	SCI_CLR_INTR(ncr_sc);
393 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
394 	*ncr_sc->sci_icmd = icmd;
395 	splx(s);
396 	return (datalen - resid);
397 }
398 
399 
400 /***
401  * The following code implements interrupt-driven PDMA.
402  ***/
403 
404 /*
405  * This is the meat of the PDMA transfer.
406  * When we get here, we shove data as fast as the mac can take it.
407  * We depend on several things:
408  *   * All macs after the Mac Plus that have a 5380 chip should have a general
409  *     logic IC that handshakes data for blind transfers.
410  *   * If the SCSI controller finishes sending/receiving data before we do,
411  *     the same general logic IC will generate a /BERR for us in short order.
412  *   * The fault address for said /BERR minus the base address for the
413  *     transfer will be the amount of data that was actually written.
414  *
415  * We use the nofault flag and the setjmp/longjmp in locore.s so we can
416  * detect and handle the bus error for early termination of a command.
417  * This is usually caused by a disconnecting target.
418  */
419 void
420 sbc_drq_intr(void *p)
421 {
422 	struct sbc_softc *sc = (struct sbc_softc *)p;
423 	struct ncr5380_softc *ncr_sc = (struct ncr5380_softc *)p;
424 	struct sci_req *sr = ncr_sc->sc_current;
425 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
426 	label_t faultbuf;
427 	volatile u_int32_t *long_drq;
428 	u_int32_t *long_data;
429 	volatile u_int8_t *drq = 0;	/* XXX gcc4 -Wuninitialized */
430 	u_int8_t *data;
431 	int count, dcount, resid;
432 	u_int8_t tmp;
433 
434 	/*
435 	 * If we're not ready to xfer data, or have no more, just return.
436 	 */
437 	if ((*ncr_sc->sci_csr & SCI_CSR_DREQ) == 0 || dh->dh_len == 0)
438 		return;
439 
440 #ifdef SBC_DEBUG
441 	if (sbc_debug & SBC_DB_INTR)
442 		printf("%s: drq intr, dh_len=0x%x, dh_flags=0x%x\n",
443 		    ncr_sc->sc_dev.dv_xname, dh->dh_len, dh->dh_flags);
444 #endif
445 
446 	/*
447 	 * Setup for a possible bus error caused by SCSI controller
448 	 * switching out of DATA-IN/OUT before we're done with the
449 	 * current transfer.
450 	 */
451 	nofault = &faultbuf;
452 
453 	if (setjmp(nofault)) {
454 		nofault = (label_t *)0;
455 		if ((dh->dh_flags & SBC_DH_DONE) == 0) {
456 			count = ((  (u_long)m68k_fault_addr
457 				  - (u_long)sc->sc_drq_addr));
458 
459 			if ((count < 0) || (count > dh->dh_len)) {
460 				printf("%s: complete=0x%x (pending 0x%x)\n",
461 				    ncr_sc->sc_dev.dv_xname, count, dh->dh_len);
462 				panic("something is wrong");
463 			}
464 
465 			dh->dh_addr += count;
466 			dh->dh_len -= count;
467 		} else
468 			count = 0;
469 
470 #ifdef SBC_DEBUG
471 		if (sbc_debug & SBC_DB_INTR)
472 			printf("%s: drq /berr, complete=0x%x (pending 0x%x)\n",
473 			   ncr_sc->sc_dev.dv_xname, count, dh->dh_len);
474 #endif
475 		m68k_fault_addr = 0;
476 
477 		return;
478 	}
479 
480 	if (dh->dh_flags & SBC_DH_OUT) { /* Data Out */
481 		dcount = 0;
482 
483 		/*
484 		 * Get the source address aligned.
485 		 */
486 		resid =
487 		    count = min(dh->dh_len, 4 - (((int)dh->dh_addr) & 0x3));
488 		if (count && count < 4) {
489 			drq = (volatile u_int8_t *)sc->sc_drq_addr;
490 			data = (u_int8_t *)dh->dh_addr;
491 
492 #define W1		*drq++ = *data++
493 			while (count) {
494 				W1; count--;
495 			}
496 #undef W1
497 			dh->dh_addr += resid;
498 			dh->dh_len -= resid;
499 		}
500 
501 		/*
502 		 * Start the transfer.
503 		 */
504 		while (dh->dh_len) {
505 			dcount = count = min(dh->dh_len, MAX_DMA_LEN);
506 			long_drq = (volatile u_int32_t *)sc->sc_drq_addr;
507 			long_data = (u_int32_t *)dh->dh_addr;
508 
509 #define W4		*long_drq++ = *long_data++
510 			while (count >= 64) {
511 				W4; W4; W4; W4; W4; W4; W4; W4;
512 				W4; W4; W4; W4; W4; W4; W4; W4; /*  64 */
513 				count -= 64;
514 			}
515 			while (count >= 4) {
516 				W4; count -= 4;
517 			}
518 #undef W4
519 			data = (u_int8_t *)long_data;
520 			drq = (volatile u_int8_t *)long_drq;
521 
522 #define W1		*drq++ = *data++
523 			while (count) {
524 				W1; count--;
525 			}
526 #undef W1
527 			dh->dh_len -= dcount;
528 			dh->dh_addr += dcount;
529 		}
530 		dh->dh_flags |= SBC_DH_DONE;
531 
532 		/*
533 		 * XXX -- Read a byte from the SBC to trigger a /BERR.
534 		 * This seems to be necessary for us to notice that
535 		 * the target has disconnected.  Ick.  06 jun 1996 (sr)
536 		 */
537 		if (dcount >= MAX_DMA_LEN)
538 			drq = (volatile u_int8_t *)sc->sc_drq_addr;
539 		tmp = *drq;
540 	} else {	/* Data In */
541 		/*
542 		 * Get the dest address aligned.
543 		 */
544 		resid =
545 		    count = min(dh->dh_len, 4 - (((int)dh->dh_addr) & 0x3));
546 		if (count && count < 4) {
547 			data = (u_int8_t *)dh->dh_addr;
548 			drq = (volatile u_int8_t *)sc->sc_drq_addr;
549 
550 #define R1		*data++ = *drq++
551 			while (count) {
552 				R1; count--;
553 			}
554 #undef R1
555 			dh->dh_addr += resid;
556 			dh->dh_len -= resid;
557 		}
558 
559 		/*
560 		 * Start the transfer.
561 		 */
562 		while (dh->dh_len) {
563 			dcount = count = min(dh->dh_len, MAX_DMA_LEN);
564 			long_data = (u_int32_t *)dh->dh_addr;
565 			long_drq = (volatile u_int32_t *)sc->sc_drq_addr;
566 
567 #define R4		*long_data++ = *long_drq++
568 			while (count >= 64) {
569 				R4; R4; R4; R4; R4; R4; R4; R4;
570 				R4; R4; R4; R4; R4; R4; R4; R4;	/* 64 */
571 				count -= 64;
572 			}
573 			while (count >= 4) {
574 				R4; count -= 4;
575 			}
576 #undef R4
577 			data = (u_int8_t *)long_data;
578 			drq = (volatile u_int8_t *)long_drq;
579 
580 #define R1		*data++ = *drq++
581 			while (count) {
582 				R1; count--;
583 			}
584 #undef R1
585 			dh->dh_len -= dcount;
586 			dh->dh_addr += dcount;
587 		}
588 		dh->dh_flags |= SBC_DH_DONE;
589 	}
590 
591 	/*
592 	 * OK.  No bus error occurred above.  Clear the nofault flag
593 	 * so we no longer short-circuit bus errors.
594 	 */
595 	nofault = (label_t *)0;
596 
597 #ifdef SBC_DEBUG
598 	if (sbc_debug & (SBC_DB_REG | SBC_DB_INTR))
599 		printf("%s: drq intr complete: csr=0x%x, bus_csr=0x%x\n",
600 		    ncr_sc->sc_dev.dv_xname, *ncr_sc->sci_csr,
601 		    *ncr_sc->sci_bus_csr);
602 #endif
603 }
604 
605 void
606 sbc_dma_alloc(struct ncr5380_softc *ncr_sc)
607 {
608 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
609 	struct sci_req *sr = ncr_sc->sc_current;
610 	struct scsipi_xfer *xs = sr->sr_xs;
611 	struct sbc_pdma_handle *dh;
612 	int		i, xlen;
613 
614 #ifdef DIAGNOSTIC
615 	if (sr->sr_dma_hand != NULL)
616 		panic("sbc_dma_alloc: already have PDMA handle");
617 #endif
618 
619 	/* Polled transfers shouldn't allocate a PDMA handle. */
620 	if (sr->sr_flags & SR_IMMED)
621 		return;
622 
623 	xlen = ncr_sc->sc_datalen;
624 
625 	/* Make sure our caller checked sc_min_dma_len. */
626 	if (xlen < MIN_DMA_LEN)
627 		panic("sbc_dma_alloc: len=0x%x", xlen);
628 
629 	/*
630 	 * Find free PDMA handle.  Guaranteed to find one since we
631 	 * have as many PDMA handles as the driver has processes.
632 	 * (instances?)
633 	 */
634 	 for (i = 0; i < SCI_OPENINGS; i++) {
635 		if ((sc->sc_pdma[i].dh_flags & SBC_DH_BUSY) == 0)
636 			goto found;
637 	}
638 	panic("sbc: no free PDMA handles");
639 found:
640 	dh = &sc->sc_pdma[i];
641 	dh->dh_flags = SBC_DH_BUSY;
642 	dh->dh_addr = ncr_sc->sc_dataptr;
643 	dh->dh_len = xlen;
644 
645 	/* Copy the 'write' flag for convenience. */
646 	if (xs->xs_control & XS_CTL_DATA_OUT)
647 		dh->dh_flags |= SBC_DH_OUT;
648 
649 	sr->sr_dma_hand = dh;
650 }
651 
652 void
653 sbc_dma_free(struct ncr5380_softc *ncr_sc)
654 {
655 	struct sci_req *sr = ncr_sc->sc_current;
656 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
657 
658 #ifdef DIAGNOSTIC
659 	if (sr->sr_dma_hand == NULL)
660 		panic("sbc_dma_free: no DMA handle");
661 #endif
662 
663 	if (ncr_sc->sc_state & NCR_DOINGDMA)
664 		panic("sbc_dma_free: free while in progress");
665 
666 	if (dh->dh_flags & SBC_DH_BUSY) {
667 		dh->dh_flags = 0;
668 		dh->dh_addr = NULL;
669 		dh->dh_len = 0;
670 	}
671 	sr->sr_dma_hand = NULL;
672 }
673 
674 void
675 sbc_dma_poll(struct ncr5380_softc *ncr_sc)
676 {
677 	struct sci_req *sr = ncr_sc->sc_current;
678 
679 	/*
680 	 * We shouldn't arrive here; if SR_IMMED is set, then
681 	 * dma_alloc() should have refused to allocate a handle
682 	 * for the transfer.  This forces the polled PDMA code
683 	 * to handle the request...
684 	 */
685 #ifdef SBC_DEBUG
686 	if (sbc_debug & SBC_DB_DMA)
687 		printf("%s: lost DRQ interrupt?\n", ncr_sc->sc_dev.dv_xname);
688 #endif
689 	sr->sr_flags |= SR_OVERDUE;
690 }
691 
692 void
693 sbc_dma_setup(struct ncr5380_softc *ncr_sc)
694 {
695 	/* Not needed; we don't have real DMA */
696 }
697 
698 void
699 sbc_dma_start(struct ncr5380_softc *ncr_sc)
700 {
701 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
702 	struct sci_req *sr = ncr_sc->sc_current;
703 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
704 
705 	/*
706 	 * Match bus phase, clear pending interrupts, set DMA mode, and
707 	 * assert data bus (for writing only), then start the transfer.
708 	 */
709 	if (dh->dh_flags & SBC_DH_OUT) {
710 		*ncr_sc->sci_tcmd = PHASE_DATA_OUT;
711 		SCI_CLR_INTR(ncr_sc);
712 		if (sc->sc_clrintr)
713 			(*sc->sc_clrintr)(ncr_sc);
714 		*ncr_sc->sci_mode |= SCI_MODE_DMA;
715 		*ncr_sc->sci_icmd = SCI_ICMD_DATA;
716 		*ncr_sc->sci_dma_send = 0;
717 	} else {
718 		*ncr_sc->sci_tcmd = PHASE_DATA_IN;
719 		SCI_CLR_INTR(ncr_sc);
720 		if (sc->sc_clrintr)
721 			(*sc->sc_clrintr)(ncr_sc);
722 		*ncr_sc->sci_mode |= SCI_MODE_DMA;
723 		*ncr_sc->sci_icmd = 0;
724 		*ncr_sc->sci_irecv = 0;
725 	}
726 	ncr_sc->sc_state |= NCR_DOINGDMA;
727 
728 #ifdef SBC_DEBUG
729 	if (sbc_debug & SBC_DB_DMA)
730 		printf("%s: PDMA started, va=%p, len=0x%x\n",
731 		    ncr_sc->sc_dev.dv_xname, dh->dh_addr, dh->dh_len);
732 #endif
733 }
734 
735 void
736 sbc_dma_eop(struct ncr5380_softc *ncr_sc)
737 {
738 	/* Not used; the EOP pin is wired high (GMFH, pp. 389-390) */
739 }
740 
741 void
742 sbc_dma_stop(struct ncr5380_softc *ncr_sc)
743 {
744 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
745 	struct sci_req *sr = ncr_sc->sc_current;
746 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
747 	int ntrans;
748 
749 	if ((ncr_sc->sc_state & NCR_DOINGDMA) == 0) {
750 #ifdef SBC_DEBUG
751 		if (sbc_debug & SBC_DB_DMA)
752 			printf("%s: dma_stop: DMA not running\n",
753 			    ncr_sc->sc_dev.dv_xname);
754 #endif
755 		return;
756 	}
757 	ncr_sc->sc_state &= ~NCR_DOINGDMA;
758 
759 	if ((ncr_sc->sc_state & NCR_ABORTING) == 0) {
760 		ntrans = ncr_sc->sc_datalen - dh->dh_len;
761 
762 #ifdef SBC_DEBUG
763 		if (sbc_debug & SBC_DB_DMA)
764 			printf("%s: dma_stop: ntrans=0x%x\n",
765 			    ncr_sc->sc_dev.dv_xname, ntrans);
766 #endif
767 
768 		if (ntrans > ncr_sc->sc_datalen)
769 			panic("sbc_dma_stop: excess transfer");
770 
771 		/* Adjust data pointer */
772 		ncr_sc->sc_dataptr += ntrans;
773 		ncr_sc->sc_datalen -= ntrans;
774 
775 		/* Clear any pending interrupts. */
776 		SCI_CLR_INTR(ncr_sc);
777 		if (sc->sc_clrintr)
778 			(*sc->sc_clrintr)(ncr_sc);
779 	}
780 
781 	/* Put SBIC back into PIO mode. */
782 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
783 	*ncr_sc->sci_icmd = 0;
784 
785 #ifdef SBC_DEBUG
786 	if (sbc_debug & SBC_DB_REG)
787 		printf("%s: dma_stop: csr=0x%x, bus_csr=0x%x\n",
788 		    ncr_sc->sc_dev.dv_xname, *ncr_sc->sci_csr,
789 		    *ncr_sc->sci_bus_csr);
790 #endif
791 }
792