xref: /netbsd-src/sys/arch/mac68k/obio/esp.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: esp.c,v 1.43 2005/12/24 23:24:01 perry Exp $	*/
2 
3 /*
4  * Copyright (c) 1997 Jason R. Thorpe.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed for the NetBSD Project
18  *	by Jason R. Thorpe.
19  * 4. The name of the author may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 /*
35  * Copyright (c) 1994 Peter Galbavy
36  * All rights reserved.
37  *
38  * Redistribution and use in source and binary forms, with or without
39  * modification, are permitted provided that the following conditions
40  * are met:
41  * 1. Redistributions of source code must retain the above copyright
42  *    notice, this list of conditions and the following disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  * 3. All advertising materials mentioning features or use of this software
47  *    must display the following acknowledgement:
48  *	This product includes software developed by Peter Galbavy
49  * 4. The name of the author may not be used to endorse or promote products
50  *    derived from this software without specific prior written permission.
51  *
52  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
53  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
54  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
55  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
56  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
57  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
58  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
60  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
61  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
62  * POSSIBILITY OF SUCH DAMAGE.
63  */
64 
65 /*
66  * Based on aic6360 by Jarle Greipsland
67  *
68  * Acknowledgements: Many of the algorithms used in this driver are
69  * inspired by the work of Julian Elischer (julian@tfs.com) and
70  * Charles Hannum (mycroft@duality.gnu.ai.mit.edu).  Thanks a million!
71  */
72 
73 /*
74  * Initial m68k mac support from Allen Briggs <briggs@macbsd.com>
75  * (basically consisting of the match, a bit of the attach, and the
76  *  "DMA" glue functions).
77  */
78 
79 #include <sys/cdefs.h>
80 __KERNEL_RCSID(0, "$NetBSD: esp.c,v 1.43 2005/12/24 23:24:01 perry Exp $");
81 
82 #include <sys/types.h>
83 #include <sys/param.h>
84 #include <sys/systm.h>
85 #include <sys/kernel.h>
86 #include <sys/errno.h>
87 #include <sys/ioctl.h>
88 #include <sys/device.h>
89 #include <sys/buf.h>
90 #include <sys/proc.h>
91 #include <sys/user.h>
92 #include <sys/queue.h>
93 
94 #include <dev/scsipi/scsi_all.h>
95 #include <dev/scsipi/scsipi_all.h>
96 #include <dev/scsipi/scsiconf.h>
97 #include <dev/scsipi/scsi_message.h>
98 
99 #include <machine/cpu.h>
100 #include <machine/bus.h>
101 #include <machine/param.h>
102 
103 #include <dev/ic/ncr53c9xreg.h>
104 #include <dev/ic/ncr53c9xvar.h>
105 
106 #include <machine/viareg.h>
107 
108 #include <mac68k/obio/espvar.h>
109 #include <mac68k/obio/obiovar.h>
110 
111 void	espattach(struct device *, struct device *, void *);
112 int	espmatch(struct device *, struct cfdata *, void *);
113 
114 /* Linkup to the rest of the kernel */
115 CFATTACH_DECL(esp, sizeof(struct esp_softc),
116     espmatch, espattach, NULL, NULL);
117 
118 /*
119  * Functions and the switch for the MI code.
120  */
121 u_char	esp_read_reg(struct ncr53c9x_softc *, int);
122 void	esp_write_reg(struct ncr53c9x_softc *, int, u_char);
123 int	esp_dma_isintr(struct ncr53c9x_softc *);
124 void	esp_dma_reset(struct ncr53c9x_softc *);
125 int	esp_dma_intr(struct ncr53c9x_softc *);
126 int	esp_dma_setup(struct ncr53c9x_softc *, caddr_t *, size_t *, int,
127 	    size_t *);
128 void	esp_dma_go(struct ncr53c9x_softc *);
129 void	esp_dma_stop(struct ncr53c9x_softc *);
130 int	esp_dma_isactive(struct ncr53c9x_softc *);
131 void	esp_quick_write_reg(struct ncr53c9x_softc *, int, u_char);
132 int	esp_quick_dma_intr(struct ncr53c9x_softc *);
133 int	esp_quick_dma_setup(struct ncr53c9x_softc *, caddr_t *, size_t *, int,
134 	     size_t *);
135 void	esp_quick_dma_go(struct ncr53c9x_softc *);
136 
137 void	esp_intr(void *);
138 void	esp_dualbus_intr(void *);
139 static struct esp_softc		*esp0, *esp1;
140 
141 static inline int esp_dafb_have_dreq(struct esp_softc *);
142 static inline int esp_iosb_have_dreq(struct esp_softc *);
143 int (*esp_have_dreq)(struct esp_softc *);
144 
145 struct ncr53c9x_glue esp_glue = {
146 	esp_read_reg,
147 	esp_write_reg,
148 	esp_dma_isintr,
149 	esp_dma_reset,
150 	esp_dma_intr,
151 	esp_dma_setup,
152 	esp_dma_go,
153 	esp_dma_stop,
154 	esp_dma_isactive,
155 	NULL,			/* gl_clear_latched_intr */
156 };
157 
158 int
159 espmatch(struct device *parent, struct cfdata *cf, void *aux)
160 {
161 	struct obio_attach_args *oa = (struct obio_attach_args *)aux;
162 
163 	if (oa->oa_addr == 0 && mac68k_machine.scsi96) {
164 		return 1;
165 	}
166 	if (oa->oa_addr == 1 && mac68k_machine.scsi96_2) {
167 		return 1;
168 	}
169 	return 0;
170 }
171 
172 /*
173  * Attach this instance, and then all the sub-devices
174  */
175 void
176 espattach(struct device *parent, struct device *self, void *aux)
177 {
178 	struct obio_attach_args *oa = (struct obio_attach_args *)aux;
179 	extern vaddr_t		SCSIBase;
180 	struct esp_softc	*esc = (void *)self;
181 	struct ncr53c9x_softc	*sc = &esc->sc_ncr53c9x;
182 	int			quick = 0;
183 	unsigned long		reg_offset;
184 
185 	reg_offset = SCSIBase - IOBase;
186 	esc->sc_tag = oa->oa_tag;
187 
188 	/*
189 	 * For Wombat, Primus and Optimus motherboards, DREQ is
190 	 * visible on bit 0 of the IOSB's emulated VIA2 vIFR (and
191 	 * the scsi registers are offset 0x1000 bytes from IOBase).
192 	 *
193 	 * For the Q700/900/950 it's at f9800024 for bus 0 and
194 	 * f9800028 for bus 1 (900/950).  For these machines, that is also
195 	 * a (12-bit) configuration register for DAFB's control of the
196 	 * pseudo-DMA timing.  The default value is 0x1d1.
197 	 */
198 	esp_have_dreq = esp_dafb_have_dreq;
199 	if (oa->oa_addr == 0) {
200 		if (reg_offset == 0x10000) {
201 			quick = 1;
202 			esp_have_dreq = esp_iosb_have_dreq;
203 		} else if (reg_offset == 0x18000) {
204 			quick = 0;
205 		} else {
206 			if (bus_space_map(esc->sc_tag, 0xf9800024,
207 					  4, 0, &esc->sc_bsh)) {
208 				printf("failed to map 4 at 0xf9800024.\n");
209 			} else {
210 				quick = 1;
211 				bus_space_write_4(esc->sc_tag,
212 						  esc->sc_bsh, 0, 0x1d1);
213 			}
214 		}
215 	} else {
216 		if (bus_space_map(esc->sc_tag, 0xf9800028,
217 				  4, 0, &esc->sc_bsh)) {
218 			printf("failed to map 4 at 0xf9800028.\n");
219 		} else {
220 			quick = 1;
221 			bus_space_write_4(esc->sc_tag, esc->sc_bsh, 0, 0x1d1);
222 		}
223 	}
224 	if (quick) {
225 		esp_glue.gl_write_reg = esp_quick_write_reg;
226 		esp_glue.gl_dma_intr = esp_quick_dma_intr;
227 		esp_glue.gl_dma_setup = esp_quick_dma_setup;
228 		esp_glue.gl_dma_go = esp_quick_dma_go;
229 	}
230 
231 	/*
232 	 * Set up the glue for MI code early; we use some of it here.
233 	 */
234 	sc->sc_glue = &esp_glue;
235 
236 	/*
237 	 * Save the regs
238 	 */
239 	if (oa->oa_addr == 0) {
240 		esp0 = esc;
241 
242 		esc->sc_reg = (volatile u_char *) SCSIBase;
243 		via2_register_irq(VIA2_SCSIIRQ, esp_intr, esc);
244 		esc->irq_mask = V2IF_SCSIIRQ;
245 		if (reg_offset == 0x10000) {
246 			/* From the Q650 developer's note */
247 			sc->sc_freq = 16500000;
248 		} else {
249 			sc->sc_freq = 25000000;
250 		}
251 
252 		if (esp_glue.gl_dma_go == esp_quick_dma_go) {
253 			printf(" (quick)");
254 		}
255 	} else {
256 		esp1 = esc;
257 
258 		esc->sc_reg = (volatile u_char *) SCSIBase + 0x402;
259 		via2_register_irq(VIA2_SCSIIRQ, esp_dualbus_intr, NULL);
260 		esc->irq_mask = 0;
261 		sc->sc_freq = 25000000;
262 
263 		if (esp_glue.gl_dma_go == esp_quick_dma_go) {
264 			printf(" (quick)");
265 		}
266 	}
267 
268 	printf(": address %p", esc->sc_reg);
269 
270 	sc->sc_id = 7;
271 
272 	/* gimme Mhz */
273 	sc->sc_freq /= 1000000;
274 
275 	/*
276 	 * It is necessary to try to load the 2nd config register here,
277 	 * to find out what rev the esp chip is, else the esp_reset
278 	 * will not set up the defaults correctly.
279 	 */
280 	sc->sc_cfg1 = sc->sc_id; /* | NCRCFG1_PARENB; */
281 	sc->sc_cfg2 = NCRCFG2_SCSI2;
282 	sc->sc_cfg3 = 0;
283 	sc->sc_rev = NCR_VARIANT_NCR53C96;
284 
285 	/*
286 	 * This is the value used to start sync negotiations
287 	 * Note that the NCR register "SYNCTP" is programmed
288 	 * in "clocks per byte", and has a minimum value of 4.
289 	 * The SCSI period used in negotiation is one-fourth
290 	 * of the time (in nanoseconds) needed to transfer one byte.
291 	 * Since the chip's clock is given in MHz, we have the following
292 	 * formula: 4 * period = (1000 / freq) * 4
293 	 */
294 	sc->sc_minsync = 1000 / sc->sc_freq;
295 
296 	/* We need this to fit into the TCR... */
297 	sc->sc_maxxfer = 64 * 1024;
298 
299 	if (!quick) {
300 		sc->sc_minsync = 0;	/* No synchronous xfers w/o DMA */
301 		sc->sc_maxxfer = 8 * 1024;
302 	}
303 
304 	/*
305 	 * Configure interrupts.
306 	 */
307 	if (esc->irq_mask) {
308 		via2_reg(vPCR) = 0x22;
309 		via2_reg(vIFR) = esc->irq_mask;
310 		via2_reg(vIER) = 0x80 | esc->irq_mask;
311 	}
312 
313 	/*
314 	 * Now try to attach all the sub-devices
315 	 */
316 	sc->sc_adapter.adapt_minphys = minphys;
317 	sc->sc_adapter.adapt_request = ncr53c9x_scsipi_request;
318 	ncr53c9x_attach(sc);
319 }
320 
321 /*
322  * Glue functions.
323  */
324 
325 u_char
326 esp_read_reg(struct ncr53c9x_softc *sc, int reg)
327 {
328 	struct esp_softc *esc = (struct esp_softc *)sc;
329 
330 	return esc->sc_reg[reg * 16];
331 }
332 
333 void
334 esp_write_reg(struct ncr53c9x_softc *sc, int reg, u_char val)
335 {
336 	struct esp_softc *esc = (struct esp_softc *)sc;
337 	u_char	v = val;
338 
339 	if (reg == NCR_CMD && v == (NCRCMD_TRANS|NCRCMD_DMA)) {
340 		v = NCRCMD_TRANS;
341 	}
342 	esc->sc_reg[reg * 16] = v;
343 }
344 
345 void
346 esp_dma_stop(struct ncr53c9x_softc *sc)
347 {
348 }
349 
350 int
351 esp_dma_isactive(struct ncr53c9x_softc *sc)
352 {
353 	struct esp_softc *esc = (struct esp_softc *)sc;
354 
355 	return esc->sc_active;
356 }
357 
358 int
359 esp_dma_isintr(struct ncr53c9x_softc *sc)
360 {
361 	struct esp_softc *esc = (struct esp_softc *)sc;
362 
363 	return esc->sc_reg[NCR_STAT * 16] & 0x80;
364 }
365 
366 void
367 esp_dma_reset(struct ncr53c9x_softc *sc)
368 {
369 	struct esp_softc *esc = (struct esp_softc *)sc;
370 
371 	esc->sc_active = 0;
372 	esc->sc_tc = 0;
373 }
374 
375 int
376 esp_dma_intr(struct ncr53c9x_softc *sc)
377 {
378 	struct esp_softc *esc = (struct esp_softc *)sc;
379 	volatile u_char *cmdreg, *intrreg, *statreg, *fiforeg;
380 	u_char	*p;
381 	u_int	espphase, espstat, espintr;
382 	int	cnt, s;
383 
384 	if (esc->sc_active == 0) {
385 		printf("dma_intr--inactive DMA\n");
386 		return -1;
387 	}
388 
389 	if ((sc->sc_espintr & NCRINTR_BS) == 0) {
390 		esc->sc_active = 0;
391 		return 0;
392 	}
393 
394 	cnt = *esc->sc_dmalen;
395 	if (*esc->sc_dmalen == 0) {
396 		printf("data interrupt, but no count left.");
397 	}
398 
399 	p = *esc->sc_dmaaddr;
400 	espphase = sc->sc_phase;
401 	espstat = (u_int) sc->sc_espstat;
402 	espintr = (u_int) sc->sc_espintr;
403 	cmdreg = esc->sc_reg + NCR_CMD * 16;
404 	fiforeg = esc->sc_reg + NCR_FIFO * 16;
405 	statreg = esc->sc_reg + NCR_STAT * 16;
406 	intrreg = esc->sc_reg + NCR_INTR * 16;
407 	do {
408 		if (esc->sc_datain) {
409 			*p++ = *fiforeg;
410 			cnt--;
411 			if (espphase == DATA_IN_PHASE) {
412 				*cmdreg = NCRCMD_TRANS;
413 			} else {
414 				esc->sc_active = 0;
415 			}
416 	 	} else {
417 			if (   (espphase == DATA_OUT_PHASE)
418 			    || (espphase == MESSAGE_OUT_PHASE)) {
419 				*fiforeg = *p++;
420 				cnt--;
421 				*cmdreg = NCRCMD_TRANS;
422 			} else {
423 				esc->sc_active = 0;
424 			}
425 		}
426 
427 		if (esc->sc_active) {
428 			while (!(*statreg & 0x80));
429 			s = splhigh();
430 			espstat = *statreg;
431 			espintr = *intrreg;
432 			espphase = (espintr & NCRINTR_DIS)
433 				    ? /* Disconnected */ BUSFREE_PHASE
434 				    : espstat & PHASE_MASK;
435 			splx(s);
436 		}
437 	} while (esc->sc_active && (espintr & NCRINTR_BS));
438 	sc->sc_phase = espphase;
439 	sc->sc_espstat = (u_char) espstat;
440 	sc->sc_espintr = (u_char) espintr;
441 	*esc->sc_dmaaddr = p;
442 	*esc->sc_dmalen = cnt;
443 
444 	if (*esc->sc_dmalen == 0) {
445 		esc->sc_tc = NCRSTAT_TC;
446 	}
447 	sc->sc_espstat |= esc->sc_tc;
448 	return 0;
449 }
450 
451 int
452 esp_dma_setup(struct ncr53c9x_softc *sc, caddr_t *addr, size_t *len, int datain,
453     size_t *dmasize)
454 {
455 	struct esp_softc *esc = (struct esp_softc *)sc;
456 
457 	esc->sc_dmaaddr = addr;
458 	esc->sc_dmalen = len;
459 	esc->sc_datain = datain;
460 	esc->sc_dmasize = *dmasize;
461 	esc->sc_tc = 0;
462 
463 	return 0;
464 }
465 
466 void
467 esp_dma_go(struct ncr53c9x_softc *sc)
468 {
469 	struct esp_softc *esc = (struct esp_softc *)sc;
470 
471 	if (esc->sc_datain == 0) {
472 		esc->sc_reg[NCR_FIFO * 16] = **esc->sc_dmaaddr;
473 		(*esc->sc_dmalen)--;
474 		(*esc->sc_dmaaddr)++;
475 	}
476 	esc->sc_active = 1;
477 }
478 
479 void
480 esp_quick_write_reg(struct ncr53c9x_softc *sc, int reg, u_char val)
481 {
482 	struct esp_softc *esc = (struct esp_softc *)sc;
483 
484 	esc->sc_reg[reg * 16] = val;
485 }
486 
487 #if DEBUG
488 int mac68k_esp_debug=0;
489 #endif
490 
491 int
492 esp_quick_dma_intr(struct ncr53c9x_softc *sc)
493 {
494 	struct esp_softc *esc = (struct esp_softc *)sc;
495 	int trans=0, resid=0;
496 
497 	if (esc->sc_active == 0)
498 		panic("dma_intr--inactive DMA");
499 
500 	esc->sc_active = 0;
501 
502 	if (esc->sc_dmasize == 0) {
503 		int	res;
504 
505 		res = NCR_READ_REG(sc, NCR_TCL);
506 		res += NCR_READ_REG(sc, NCR_TCM) << 8;
507 		/* This can happen in the case of a TRPAD operation */
508 		/* Pretend that it was complete */
509 		sc->sc_espstat |= NCRSTAT_TC;
510 #if DEBUG
511 		if (mac68k_esp_debug) {
512 			printf("dmaintr: DMA xfer of zero xferred %d\n",
513 			    65536 - res);
514 		}
515 #endif
516 		return 0;
517 	}
518 
519 	if ((sc->sc_espstat & NCRSTAT_TC) == 0) {
520 		if (esc->sc_datain == 0) {
521 			resid = NCR_READ_REG(sc, NCR_FFLAG) & 0x1f;
522 #if DEBUG
523 			if (mac68k_esp_debug) {
524 				printf("Write FIFO residual %d bytes\n", resid);
525 			}
526 #endif
527 		}
528 		resid += NCR_READ_REG(sc, NCR_TCL);
529 		resid += NCR_READ_REG(sc, NCR_TCM) << 8;
530 		if (resid == 0)
531 			resid = 65536;
532 	}
533 
534 	trans = esc->sc_dmasize - resid;
535 	if (trans < 0) {
536 		printf("dmaintr: trans < 0????");
537 		trans = *esc->sc_dmalen;
538 	}
539 
540 	NCR_DMA(("dmaintr: trans %d, resid %d.\n", trans, resid));
541 #if DEBUG
542 	if (mac68k_esp_debug) {
543 		printf("eqd_intr: trans %d, resid %d.\n", trans, resid);
544 	}
545 #endif
546 	*esc->sc_dmaaddr += trans;
547 	*esc->sc_dmalen -= trans;
548 
549 	return 0;
550 }
551 
552 int
553 esp_quick_dma_setup(struct ncr53c9x_softc *sc, caddr_t *addr, size_t *len,
554     int datain, size_t *dmasize)
555 {
556 	struct esp_softc *esc = (struct esp_softc *)sc;
557 
558 	esc->sc_dmaaddr = addr;
559 	esc->sc_dmalen = len;
560 
561 	if (*len & 1) {
562 		esc->sc_pad = 1;
563 	} else {
564 		esc->sc_pad = 0;
565 	}
566 
567 	esc->sc_datain = datain;
568 	esc->sc_dmasize = *dmasize;
569 
570 #if DIAGNOSTIC
571 	if (esc->sc_dmasize == 0) {
572 		/* This can happen in the case of a TRPAD operation */
573 	}
574 #endif
575 #if DEBUG
576 	if (mac68k_esp_debug) {
577 	printf("eqd_setup: addr %lx, len %lx, in? %d, dmasize %lx\n",
578 	    (long) *addr, (long) *len, datain, (long) esc->sc_dmasize);
579 	}
580 #endif
581 
582 	return 0;
583 }
584 
585 static inline int
586 esp_dafb_have_dreq(struct esp_softc *esc)
587 {
588 	return (*(volatile u_int32_t *)(esc->sc_bsh.base) & 0x200);
589 }
590 
591 static inline int
592 esp_iosb_have_dreq(struct esp_softc *esc)
593 {
594 	return (via2_reg(vIFR) & V2IF_SCSIDRQ);
595 }
596 
597 static volatile int espspl=-1;
598 
599 /*
600  * Apple "DMA" is weird.
601  *
602  * Basically, the CPU acts like the DMA controller.  The DREQ/ off the
603  * chip goes to a register that we've mapped at attach time (on the
604  * IOSB or DAFB, depending on the machine).  Apple also provides some
605  * space for which the memory controller handshakes data to/from the
606  * NCR chip with the DACK/ line.  This space appears to be mapped over
607  * and over, every 4 bytes, but only the lower 16 bits are valid (but
608  * reading the upper 16 bits will handshake DACK/ just fine, so if you
609  * read *u_int16_t++ = *u_int16_t++ in a loop, you'll get
610  * <databyte><databyte>0xff0xff<databyte><databyte>0xff0xff...
611  *
612  * When you're attempting to read or write memory to this DACK/ed space,
613  * and the NCR is not ready for some timeout period, the system will
614  * generate a bus error.  This might be for one of several reasons:
615  *
616  *	1) (on write) The FIFO is full and is not draining.
617  *	2) (on read) The FIFO is empty and is not filling.
618  *	3) An interrupt condition has occurred.
619  *	4) Anything else?
620  *
621  * So if a bus error occurs, we first turn off the nofault bus error handler,
622  * then we check for an interrupt (which would render the first two
623  * possibilities moot).  If there's no interrupt, check for a DREQ/.  If we
624  * have that, then attempt to resume stuffing (or unstuffing) the FIFO.  If
625  * neither condition holds, pause briefly and check again.
626  *
627  * NOTE!!!  In order to make allowances for the hardware structure of
628  *          the mac, spl values in here are hardcoded!!!!!!!!!
629  *          This is done to allow serial interrupts to get in during
630  *          scsi transfers.  This is ugly.
631  */
632 void
633 esp_quick_dma_go(struct ncr53c9x_softc *sc)
634 {
635 	struct esp_softc *esc = (struct esp_softc *)sc;
636 	extern long mac68k_a2_fromfault;
637 	extern int *nofault;
638 	label_t faultbuf;
639 	u_int16_t volatile *pdma;
640 	u_int16_t *addr;
641 	int		len, res;
642 	u_short		cnt32, cnt2;
643 	u_char volatile *statreg;
644 
645 	esc->sc_active = 1;
646 
647 	espspl = splhigh();
648 
649 	addr = (u_int16_t *) *esc->sc_dmaaddr;
650 	len  = esc->sc_dmasize;
651 
652 restart_dmago:
653 #if DEBUG
654 	if (mac68k_esp_debug) {
655 		printf("eqdg: a %lx, l %lx, in? %d ... ",
656 		    (long) addr, (long) len, esc->sc_datain);
657 	}
658 #endif
659 	nofault = (int *) &faultbuf;
660 	if (setjmp((label_t *) nofault)) {
661 		int	i=0;
662 
663 		nofault = (int *) 0;
664 #if DEBUG
665 		if (mac68k_esp_debug) {
666 			printf("be\n");
667 		}
668 #endif
669 		/*
670 		 * Bus error...
671 		 * So, we first check for an interrupt.  If we have
672 		 * one, go handle it.  Next we check for DREQ/.  If
673 		 * we have it, then we restart the transfer.  If
674 		 * neither, then loop until we get one or the other.
675 		 */
676 		statreg = esc->sc_reg + NCR_STAT * 16;
677 		for (;;) {
678 			spl2();		/* Give serial a chance... */
679 			splhigh();	/* That's enough... */
680 
681 			if (*statreg & 0x80) {
682 				goto gotintr;
683 			}
684 
685 			if (esp_have_dreq(esc)) {
686 				/*
687 				 * Get the remaining length from the address
688 				 * differential.
689 				 */
690 				addr = (u_int16_t *) mac68k_a2_fromfault;
691 				len = esc->sc_dmasize -
692 				    ((long) addr - (long) *esc->sc_dmaaddr);
693 
694 				if (esc->sc_datain == 0) {
695 					/*
696 					 * Let the FIFO drain before we read
697 					 * the transfer count.
698 					 * Do we need to do this?
699 					 * Can we do this?
700 					 */
701 					while (NCR_READ_REG(sc, NCR_FFLAG)
702 					    & 0x1f);
703 					/*
704 					 * Get the length from the transfer
705 					 * counters.
706 					 */
707 					res = NCR_READ_REG(sc, NCR_TCL);
708 					res += NCR_READ_REG(sc, NCR_TCM) << 8;
709 					/*
710 					 * If they don't agree,
711 					 * adjust accordingly.
712 					 */
713 					while (res > len) {
714 						len+=2; addr--;
715 					}
716 					if (res != len) {
717 						panic("esp_quick_dma_go: res %d != len %d",
718 							res, len);
719 					}
720 				}
721 				break;
722 			}
723 
724 			DELAY(1);
725 			if (i++ > 1000000)
726 				panic("esp_dma_go: Bus error, but no condition!  Argh!");
727 		}
728 		goto restart_dmago;
729 	}
730 
731 	len &= ~1;
732 
733 	statreg = esc->sc_reg + NCR_STAT * 16;
734 	pdma = (volatile u_int16_t *) (esc->sc_reg + 0x100);
735 
736 	/*
737 	 * These loops are unrolled into assembly for two reasons:
738 	 * 1) We can make sure that they are as efficient as possible, and
739 	 * 2) (more importantly) we need the address that we are reading
740 	 *    from or writing to to be in a2.
741 	 */
742 	cnt32 = len / 32;
743 	cnt2 = (len % 32) / 2;
744 	if (esc->sc_datain == 0) {
745 		/* while (cnt32--) { 16 instances of *pdma = *addr++; } */
746 		/* while (cnt2--) { *pdma = *addr++; } */
747 		__asm volatile (
748 			"	movl %1, %%a2	\n"
749 			"	movl %2, %%a3	\n"
750 			"	movw %3, %%d2	\n"
751 			"	cmpw #0, %%d2	\n"
752 			"	beq  2f		\n"
753 			"	subql #1, %%d2	\n"
754 			"1:	movw %%a2@+,%%a3@; movw %%a2@+,%%a3@	\n"
755 			"	movw %%a2@+,%%a3@; movw %%a2@+,%%a3@	\n"
756 			"	movw %%a2@+,%%a3@; movw %%a2@+,%%a3@	\n"
757 			"	movw %%a2@+,%%a3@; movw %%a2@+,%%a3@	\n"
758 			"	movw %%a2@+,%%a3@; movw %%a2@+,%%a3@	\n"
759 			"	movw %%a2@+,%%a3@; movw %%a2@+,%%a3@	\n"
760 			"	movw %%a2@+,%%a3@; movw %%a2@+,%%a3@	\n"
761 			"	movw %%a2@+,%%a3@; movw %%a2@+,%%a3@	\n"
762 			"	movw #8704,%%sr	\n"
763 			"	movw #9728,%%sr	\n"
764 			"	dbra %%d2, 1b	\n"
765 			"2:	movw %4, %%d2	\n"
766 			"	cmpw #0, %%d2	\n"
767 			"	beq  4f		\n"
768 			"	subql #1, %%d2	\n"
769 			"3:	movw %%a2@+,%%a3@ \n"
770 			"	dbra %%d2, 3b	\n"
771 			"4:	movl %%a2, %0"
772 			: "=g" (addr)
773 			: "0" (addr), "g" (pdma), "g" (cnt32), "g" (cnt2)
774 			: "a2", "a3", "d2");
775 		if (esc->sc_pad) {
776 			volatile unsigned char	*c;
777 			c = (volatile unsigned char *) addr;
778 			/* Wait for DREQ */
779 			while (!esp_have_dreq(esc)) {
780 				if (*statreg & 0x80) {
781 					nofault = (int *) 0;
782 					goto gotintr;
783 				}
784 			}
785 			*(volatile unsigned char *)pdma = *c;
786 		}
787 	} else {
788 		/* while (cnt32--) { 16 instances of *addr++ = *pdma; } */
789 		/* while (cnt2--) { *addr++ = *pdma; } */
790 		__asm volatile (
791 			"	movl %1, %%a2	\n"
792 			"	movl %2, %%a3	\n"
793 			"	movw %3, %%d2	\n"
794 			"	cmpw #0, %%d2	\n"
795 			"	beq  6f		\n"
796 			"	subql #1, %%d2	\n"
797 			"5:	movw %%a3@,%%a2@+; movw %%a3@,%%a2@+	\n"
798 			"	movw %%a3@,%%a2@+; movw %%a3@,%%a2@+	\n"
799 			"	movw %%a3@,%%a2@+; movw %%a3@,%%a2@+	\n"
800 			"	movw %%a3@,%%a2@+; movw %%a3@,%%a2@+	\n"
801 			"	movw %%a3@,%%a2@+; movw %%a3@,%%a2@+	\n"
802 			"	movw %%a3@,%%a2@+; movw %%a3@,%%a2@+	\n"
803 			"	movw %%a3@,%%a2@+; movw %%a3@,%%a2@+	\n"
804 			"	movw %%a3@,%%a2@+; movw %%a3@,%%a2@+	\n"
805 			"	movw #8704,%%sr	\n"
806 			"	movw #9728,%%sr	\n"
807 			"	dbra %%d2, 5b	\n"
808 			"6:	movw %4, %%d2	\n"
809 			"	cmpw #0, %%d2	\n"
810 			"	beq  8f		\n"
811 			"	subql #1, %%d2	\n"
812 			"7:	movw %%a3@,%%a2@+ \n"
813 			"	dbra %%d2, 7b	\n"
814 			"8:	movl %%a2, %0"
815 			: "=g" (addr)
816 			: "0" (addr), "g" (pdma), "g" (cnt32), "g" (cnt2)
817 			: "a2", "a3", "d2");
818 		if (esc->sc_pad) {
819 			volatile unsigned char	*c;
820 			c = (volatile unsigned char *) addr;
821 			/* Wait for DREQ */
822 			while (!esp_have_dreq(esc)) {
823 				if (*statreg & 0x80) {
824 					nofault = (int *) 0;
825 					goto gotintr;
826 				}
827 			}
828 			*c = *(volatile unsigned char *)pdma;
829 		}
830 	}
831 
832 	nofault = (int *) 0;
833 
834 	/*
835 	 * If we have not received an interrupt yet, we should shortly,
836 	 * and we can't prevent it, so return and wait for it.
837 	 */
838 	if ((*statreg & 0x80) == 0) {
839 #if DEBUG
840 		if (mac68k_esp_debug) {
841 			printf("g.\n");
842 		}
843 #endif
844 		if (espspl != -1) splx(espspl); espspl = -1;
845 		return;
846 	}
847 
848 gotintr:
849 #if DEBUG
850 	if (mac68k_esp_debug) {
851 		printf("g!\n");
852 	}
853 #endif
854 	ncr53c9x_intr(sc);
855 	if (espspl != -1) splx(espspl); espspl = -1;
856 }
857 
858 void
859 esp_intr(void *sc)
860 {
861 	struct esp_softc *esc = (struct esp_softc *)sc;
862 
863 	if (esc->sc_reg[NCR_STAT * 16] & 0x80) {
864 		ncr53c9x_intr((struct ncr53c9x_softc *) esp0);
865 	}
866 }
867 
868 void
869 esp_dualbus_intr(void *sc)
870 {
871 	if (esp0 && (esp0->sc_reg[NCR_STAT * 16] & 0x80)) {
872 		ncr53c9x_intr((struct ncr53c9x_softc *) esp0);
873 	}
874 
875 	if (esp1 && (esp1->sc_reg[NCR_STAT * 16] & 0x80)) {
876 		ncr53c9x_intr((struct ncr53c9x_softc *) esp1);
877 	}
878 }
879