xref: /netbsd-src/sys/arch/mac68k/dev/sbc.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: sbc.c,v 1.54 2009/11/23 00:11:44 rmind 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 1.54 2009/11/23 00:11:44 rmind 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 #define R1	*(u_int8_t *)data = *byte_data, data += 1;
278 	for (; resid >= 128; resid -= 128) {
279 		if (sbc_ready(ncr_sc))
280 			goto interrupt;
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;
284 		R4; R4; R4; R4; R4; R4; R4; R4;		/* 128 */
285 	}
286 	while (resid) {
287 		if (sbc_ready(ncr_sc))
288 			goto interrupt;
289 		R1;
290 		resid--;
291 	}
292 #undef R4
293 #undef R1
294 
295 interrupt:
296 	nofault = NULL;
297 	SCI_CLR_INTR(ncr_sc);
298 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
299 	*ncr_sc->sci_icmd = 0;
300 	splx(s);
301 	return (datalen - resid);
302 }
303 
304 int
305 sbc_pdma_out(struct ncr5380_softc *ncr_sc, int phase, int datalen, u_char *data)
306 {
307 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
308 	volatile u_int32_t *long_data = (u_int32_t *)sc->sc_drq_addr;
309 	volatile u_int8_t *byte_data = (u_int8_t *)sc->sc_nodrq_addr;
310 	label_t faultbuf;
311 	int resid, s;
312 	u_int8_t icmd;
313 
314 #if 1
315 	/* Work around lame gcc initialization bug */
316 	(void)&data;
317 #endif
318 
319 	if (datalen < ncr_sc->sc_min_dma_len ||
320 	    (sc->sc_options & SBC_PDMA) == 0)
321 		return ncr5380_pio_out(ncr_sc, phase, datalen, data);
322 
323 	s = splbio();
324 	if (sbc_wait_busy(ncr_sc)) {
325 		splx(s);
326 		return 0;
327 	}
328 
329 	icmd = *(ncr_sc->sci_icmd) & SCI_ICMD_RMASK;
330 	*ncr_sc->sci_icmd = icmd | SCI_ICMD_DATA;
331 	*ncr_sc->sci_mode |= SCI_MODE_DMA;
332 	*ncr_sc->sci_dma_send = 0;
333 
334 	/*
335 	 * Setup for a possible bus error caused by SCSI controller
336 	 * switching out of DATA OUT before we're done with the
337 	 * current transfer.  (See comment before sbc_drq_intr().)
338 	 */
339 	nofault = &faultbuf;
340 
341 	if (setjmp(nofault)) {
342 		printf("buf = 0x%lx, fault = 0x%lx\n",
343 		    (u_long)sc->sc_drq_addr, (u_long)m68k_fault_addr);
344 		panic("Unexpected bus error in sbc_pdma_out()");
345 	}
346 
347 #define W1	*byte_data = *(u_int8_t *)data, data += 1
348 #define W4	*long_data = *(u_int32_t *)data, data += 4
349 	for (resid = datalen; resid >= 64; resid -= 64) {
350 		if (sbc_ready(ncr_sc))
351 			goto interrupt;
352 		W1;
353 		if (sbc_ready(ncr_sc))
354 			goto interrupt;
355 		W1;
356 		if (sbc_ready(ncr_sc))
357 			goto interrupt;
358 		W1;
359 		if (sbc_ready(ncr_sc))
360 			goto interrupt;
361 		W1;
362 		if (sbc_ready(ncr_sc))
363 			goto interrupt;
364 		W4; W4; W4; W4;
365 		W4; W4; W4; W4;
366 		W4; W4; W4; W4;
367 		W4; W4; W4;
368 	}
369 	while (resid) {
370 		if (sbc_ready(ncr_sc))
371 			goto interrupt;
372 		W1;
373 		resid--;
374 	}
375 #undef  W1
376 #undef  W4
377 	if (sbc_wait_dreq(ncr_sc))
378 		printf("%s: timeout waiting for DREQ.\n",
379 		    device_xname(ncr_sc->sc_dev));
380 
381 	*byte_data = 0;
382 	goto done;
383 
384 interrupt:
385 	if ((*ncr_sc->sci_csr & SCI_CSR_PHASE_MATCH) == 0) {
386 		*ncr_sc->sci_icmd = icmd & ~SCI_ICMD_DATA;
387 		--resid;
388 	}
389 
390 done:
391 	SCI_CLR_INTR(ncr_sc);
392 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
393 	*ncr_sc->sci_icmd = icmd;
394 	splx(s);
395 	return (datalen - resid);
396 }
397 
398 
399 /***
400  * The following code implements interrupt-driven PDMA.
401  ***/
402 
403 /*
404  * This is the meat of the PDMA transfer.
405  * When we get here, we shove data as fast as the mac can take it.
406  * We depend on several things:
407  *   * All macs after the Mac Plus that have a 5380 chip should have a general
408  *     logic IC that handshakes data for blind transfers.
409  *   * If the SCSI controller finishes sending/receiving data before we do,
410  *     the same general logic IC will generate a /BERR for us in short order.
411  *   * The fault address for said /BERR minus the base address for the
412  *     transfer will be the amount of data that was actually written.
413  *
414  * We use the nofault flag and the setjmp/longjmp in locore.s so we can
415  * detect and handle the bus error for early termination of a command.
416  * This is usually caused by a disconnecting target.
417  */
418 void
419 sbc_drq_intr(void *p)
420 {
421 	struct sbc_softc *sc = (struct sbc_softc *)p;
422 	struct ncr5380_softc *ncr_sc = (struct ncr5380_softc *)p;
423 	struct sci_req *sr = ncr_sc->sc_current;
424 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
425 	label_t faultbuf;
426 	volatile u_int32_t *long_drq;
427 	u_int32_t *long_data;
428 	volatile u_int8_t *drq = 0;	/* XXX gcc4 -Wuninitialized */
429 	u_int8_t *data;
430 	int count, dcount, resid;
431 	u_int8_t tmp;
432 
433 	/*
434 	 * If we're not ready to xfer data, or have no more, just return.
435 	 */
436 	if ((*ncr_sc->sci_csr & SCI_CSR_DREQ) == 0 || dh->dh_len == 0)
437 		return;
438 
439 #ifdef SBC_DEBUG
440 	if (sbc_debug & SBC_DB_INTR)
441 		printf("%s: drq intr, dh_len=0x%x, dh_flags=0x%x\n",
442 		    device_xname(ncr_sc->sc_dev), dh->dh_len, dh->dh_flags);
443 #endif
444 
445 	/*
446 	 * Setup for a possible bus error caused by SCSI controller
447 	 * switching out of DATA-IN/OUT before we're done with the
448 	 * current transfer.
449 	 */
450 	nofault = &faultbuf;
451 
452 	if (setjmp(nofault)) {
453 		nofault = (label_t *)0;
454 		if ((dh->dh_flags & SBC_DH_DONE) == 0) {
455 			count = ((  (u_long)m68k_fault_addr
456 				  - (u_long)sc->sc_drq_addr));
457 
458 			if ((count < 0) || (count > dh->dh_len)) {
459 				printf("%s: complete=0x%x (pending 0x%x)\n",
460 				    device_xname(ncr_sc->sc_dev), count,
461 				    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 			   device_xname(ncr_sc->sc_dev), 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 		    device_xname(ncr_sc->sc_dev), *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",
688 		    device_xname(ncr_sc->sc_dev));
689 #endif
690 	sr->sr_flags |= SR_OVERDUE;
691 }
692 
693 void
694 sbc_dma_setup(struct ncr5380_softc *ncr_sc)
695 {
696 	/* Not needed; we don't have real DMA */
697 }
698 
699 void
700 sbc_dma_start(struct ncr5380_softc *ncr_sc)
701 {
702 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
703 	struct sci_req *sr = ncr_sc->sc_current;
704 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
705 
706 	/*
707 	 * Match bus phase, clear pending interrupts, set DMA mode, and
708 	 * assert data bus (for writing only), then start the transfer.
709 	 */
710 	if (dh->dh_flags & SBC_DH_OUT) {
711 		*ncr_sc->sci_tcmd = PHASE_DATA_OUT;
712 		SCI_CLR_INTR(ncr_sc);
713 		if (sc->sc_clrintr)
714 			(*sc->sc_clrintr)(ncr_sc);
715 		*ncr_sc->sci_mode |= SCI_MODE_DMA;
716 		*ncr_sc->sci_icmd = SCI_ICMD_DATA;
717 		*ncr_sc->sci_dma_send = 0;
718 	} else {
719 		*ncr_sc->sci_tcmd = PHASE_DATA_IN;
720 		SCI_CLR_INTR(ncr_sc);
721 		if (sc->sc_clrintr)
722 			(*sc->sc_clrintr)(ncr_sc);
723 		*ncr_sc->sci_mode |= SCI_MODE_DMA;
724 		*ncr_sc->sci_icmd = 0;
725 		*ncr_sc->sci_irecv = 0;
726 	}
727 	ncr_sc->sc_state |= NCR_DOINGDMA;
728 
729 #ifdef SBC_DEBUG
730 	if (sbc_debug & SBC_DB_DMA)
731 		printf("%s: PDMA started, va=%p, len=0x%x\n",
732 		    device_xname(ncr_sc->sc_dev), dh->dh_addr, dh->dh_len);
733 #endif
734 }
735 
736 void
737 sbc_dma_eop(struct ncr5380_softc *ncr_sc)
738 {
739 	/* Not used; the EOP pin is wired high (GMFH, pp. 389-390) */
740 }
741 
742 void
743 sbc_dma_stop(struct ncr5380_softc *ncr_sc)
744 {
745 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
746 	struct sci_req *sr = ncr_sc->sc_current;
747 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
748 	int ntrans;
749 
750 	if ((ncr_sc->sc_state & NCR_DOINGDMA) == 0) {
751 #ifdef SBC_DEBUG
752 		if (sbc_debug & SBC_DB_DMA)
753 			printf("%s: dma_stop: DMA not running\n",
754 			    device_xname(ncr_sc->sc_dev));
755 #endif
756 		return;
757 	}
758 	ncr_sc->sc_state &= ~NCR_DOINGDMA;
759 
760 	if ((ncr_sc->sc_state & NCR_ABORTING) == 0) {
761 		ntrans = ncr_sc->sc_datalen - dh->dh_len;
762 
763 #ifdef SBC_DEBUG
764 		if (sbc_debug & SBC_DB_DMA)
765 			printf("%s: dma_stop: ntrans=0x%x\n",
766 			    device_xname(ncr_sc->sc_dev), ntrans);
767 #endif
768 
769 		if (ntrans > ncr_sc->sc_datalen)
770 			panic("sbc_dma_stop: excess transfer");
771 
772 		/* Adjust data pointer */
773 		ncr_sc->sc_dataptr += ntrans;
774 		ncr_sc->sc_datalen -= ntrans;
775 
776 		/* Clear any pending interrupts. */
777 		SCI_CLR_INTR(ncr_sc);
778 		if (sc->sc_clrintr)
779 			(*sc->sc_clrintr)(ncr_sc);
780 	}
781 
782 	/* Put SBIC back into PIO mode. */
783 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
784 	*ncr_sc->sci_icmd = 0;
785 
786 #ifdef SBC_DEBUG
787 	if (sbc_debug & SBC_DB_REG)
788 		printf("%s: dma_stop: csr=0x%x, bus_csr=0x%x\n",
789 		    device_xname(ncr_sc->sc_dev), *ncr_sc->sci_csr,
790 		    *ncr_sc->sci_bus_csr);
791 #endif
792 }
793