xref: /netbsd-src/sys/arch/sparc64/dev/zs.c (revision fad4c9f71477ae11cea2ee75ec82151ac770a534)
1 /*	$NetBSD: zs.c,v 1.60 2006/03/28 23:22:08 thorpej Exp $	*/
2 
3 /*-
4  * Copyright (c) 1996 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Gordon W. Ross.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Zilog Z8530 Dual UART driver (machine-dependent part)
41  *
42  * Runs two serial lines per chip using slave drivers.
43  * Plain tty/async lines use the zs_async slave.
44  * Sun keyboard/mouse uses the zs_kbd/zs_ms slaves.
45  */
46 
47 #include <sys/cdefs.h>
48 __KERNEL_RCSID(0, "$NetBSD: zs.c,v 1.60 2006/03/28 23:22:08 thorpej Exp $");
49 
50 #include "opt_ddb.h"
51 #include "opt_kgdb.h"
52 
53 #include <sys/param.h>
54 #include <sys/systm.h>
55 #include <sys/conf.h>
56 #include <sys/device.h>
57 #include <sys/file.h>
58 #include <sys/ioctl.h>
59 #include <sys/kernel.h>
60 #include <sys/proc.h>
61 #include <sys/tty.h>
62 #include <sys/time.h>
63 #include <sys/syslog.h>
64 
65 #include <machine/autoconf.h>
66 #include <machine/openfirm.h>
67 #include <machine/cpu.h>
68 #include <machine/eeprom.h>
69 #include <machine/psl.h>
70 #include <machine/z8530var.h>
71 
72 #include <dev/cons.h>
73 #include <dev/ic/z8530reg.h>
74 #include <dev/sun/kbd_ms_ttyvar.h>
75 #include <ddb/db_output.h>
76 
77 #include <sparc64/dev/cons.h>
78 
79 #include "kbd.h"	/* NKBD */
80 #include "ms.h"		/* NMS */
81 #include "zs.h" 	/* NZS */
82 
83 /* Make life easier for the initialized arrays here. */
84 #if NZS < 3
85 #undef  NZS
86 #define NZS 3
87 #endif
88 
89 /*
90  * Some warts needed by z8530tty.c -
91  * The default parity REALLY needs to be the same as the PROM uses,
92  * or you can not see messages done with printf during boot-up...
93  */
94 int zs_def_cflag = (CREAD | CS8 | HUPCL);
95 
96 /*
97  * The Sun provides a 4.9152 MHz clock to the ZS chips.
98  */
99 #define PCLK	(9600 * 512)	/* PCLK pin input clock rate */
100 
101 #define	ZS_DELAY()
102 
103 /* The layout of this is hardware-dependent (padding, order). */
104 struct zschan {
105 	volatile u_char	zc_csr;		/* ctrl,status, and indirect access */
106 	u_char		zc_xxx0;
107 	volatile u_char	zc_data;	/* data */
108 	u_char		zc_xxx1;
109 };
110 struct zsdevice {
111 	/* Yes, they are backwards. */
112 	struct	zschan zs_chan_b;
113 	struct	zschan zs_chan_a;
114 };
115 
116 /* ZS channel used as the console device (if any) */
117 void *zs_conschan_get, *zs_conschan_put;
118 
119 /* Saved PROM mappings */
120 static struct zsdevice *zsaddr[NZS];
121 
122 static u_char zs_init_reg[16] = {
123 	0,	/* 0: CMD (reset, etc.) */
124 	0,	/* 1: No interrupts yet. */
125 	0,	/* 2: IVECT */
126 	ZSWR3_RX_8 | ZSWR3_RX_ENABLE,
127 	ZSWR4_CLK_X16 | ZSWR4_ONESB | ZSWR4_EVENP,
128 	ZSWR5_TX_8 | ZSWR5_TX_ENABLE,
129 	0,	/* 6: TXSYNC/SYNCLO */
130 	0,	/* 7: RXSYNC/SYNCHI */
131 	0,	/* 8: alias for data port */
132 	ZSWR9_MASTER_IE | ZSWR9_NO_VECTOR,
133 	0,	/*10: Misc. TX/RX control bits */
134 	ZSWR11_TXCLK_BAUD | ZSWR11_RXCLK_BAUD,
135 	((PCLK/32)/9600)-2,	/*12: BAUDLO (default=9600) */
136 	0,			/*13: BAUDHI (default=9600) */
137 	ZSWR14_BAUD_ENA | ZSWR14_BAUD_FROM_PCLK,
138 	ZSWR15_BREAK_IE,
139 };
140 
141 /* Console ops */
142 static int  zscngetc(dev_t);
143 static void zscnputc(dev_t, int);
144 static void zscnpollc(dev_t, int);
145 
146 struct consdev zs_consdev = {
147 	NULL,
148 	NULL,
149 	zscngetc,
150 	zscnputc,
151 	zscnpollc,
152 	NULL,
153 };
154 
155 
156 /****************************************************************
157  * Autoconfig
158  ****************************************************************/
159 
160 /* Definition of the driver for autoconfig. */
161 static int  zs_match_sbus(struct device *, struct cfdata *, void *);
162 static void zs_attach_sbus(struct device *, struct device *, void *);
163 
164 static void zs_attach(struct zsc_softc *, struct zsdevice *, int);
165 static int  zs_print(void *, const char *);
166 
167 CFATTACH_DECL(zs, sizeof(struct zsc_softc),
168     zs_match_sbus, zs_attach_sbus, NULL, NULL);
169 
170 extern struct cfdriver zs_cd;
171 
172 /* Interrupt handlers. */
173 int zscheckintr(void *);
174 static int zshard(void *);
175 static void zssoft(void *);
176 
177 static int zs_get_speed(struct zs_chanstate *);
178 
179 /* Console device support */
180 static int zs_console_flags(int, int, int);
181 
182 /* Power management hooks */
183 int  zs_enable(struct zs_chanstate *);
184 void zs_disable(struct zs_chanstate *);
185 
186 /* from dev/ic/z8530tty.c */
187 struct tty *zstty_get_tty_from_dev(struct device *);
188 
189 /*
190  * Is the zs chip present?
191  */
192 static int
193 zs_match_sbus(struct device *parent, struct cfdata *cf, void *aux)
194 {
195 	struct sbus_attach_args *sa = aux;
196 
197 	if (strcmp(cf->cf_name, sa->sa_name) != 0)
198 		return (0);
199 
200 	return (1);
201 }
202 
203 static void
204 zs_attach_sbus(struct device *parent, struct device *self, void *aux)
205 {
206 	struct zsc_softc *zsc = (void *) self;
207 	struct sbus_attach_args *sa = aux;
208 	bus_space_handle_t bh;
209 	int zs_unit = device_unit(&zsc->zsc_dev);
210 
211 	if (sa->sa_nintr == 0) {
212 		printf(" no interrupt lines\n");
213 		return;
214 	}
215 
216 	/* Use the mapping setup by the Sun PROM if possible. */
217 	if (zsaddr[zs_unit] == NULL) {
218 		/* Only map registers once. */
219 		if (sa->sa_npromvaddrs) {
220 			/*
221 			 * We're converting from a 32-bit pointer to a 64-bit
222 			 * pointer.  Since the 32-bit entity is negative, but
223 			 * the kernel is still mapped into the lower 4GB
224 			 * range, this needs to be zero-extended.
225 			 *
226 			 * XXXXX If we map the kernel and devices into the
227 			 * high 4GB range, this needs to be changed to
228 			 * sign-extend the address.
229 			 */
230 			sparc_promaddr_to_handle(sa->sa_bustag,
231 				sa->sa_promvaddrs[0], &bh);
232 
233 		} else {
234 
235 			if (sbus_bus_map(sa->sa_bustag, sa->sa_slot,
236 					 sa->sa_offset,
237 					 sa->sa_size,
238 					 BUS_SPACE_MAP_LINEAR,
239 					 &bh) != 0) {
240 				printf("%s @ sbus: cannot map registers\n",
241 				       self->dv_xname);
242 				return;
243 			}
244 		}
245 		zsaddr[zs_unit] = (struct zsdevice *)
246 			bus_space_vaddr(sa->sa_bustag, bh);
247 	}
248 	zsc->zsc_bustag = sa->sa_bustag;
249 	zsc->zsc_dmatag = sa->sa_dmatag;
250 	zsc->zsc_promunit = prom_getpropint(sa->sa_node, "slave", -2);
251 	zsc->zsc_node = sa->sa_node;
252 	zs_attach(zsc, zsaddr[zs_unit], sa->sa_pri);
253 }
254 
255 /*
256  * Attach a found zs.
257  *
258  * USE ROM PROPERTIES port-a-ignore-cd AND port-b-ignore-cd FOR
259  * SOFT CARRIER, AND keyboard PROPERTY FOR KEYBOARD/MOUSE?
260  */
261 static void
262 zs_attach(struct zsc_softc *zsc, struct zsdevice *zsd, int pri)
263 {
264 	struct zsc_attach_args zsc_args;
265 	struct zs_chanstate *cs;
266 	int s, channel, softpri = PIL_TTY;
267 
268 	if (zsd == NULL) {
269 		printf("configuration incomplete\n");
270 		return;
271 	}
272 
273 	printf(" softpri %d\n", softpri);
274 
275 	/*
276 	 * Initialize software state for each channel.
277 	 */
278 	for (channel = 0; channel < 2; channel++) {
279 		struct zschan *zc;
280 		struct device *child;
281 
282 		zsc_args.channel = channel;
283 		cs = &zsc->zsc_cs_store[channel];
284 		zsc->zsc_cs[channel] = cs;
285 
286 		simple_lock_init(&cs->cs_lock);
287 		cs->cs_channel = channel;
288 		cs->cs_private = NULL;
289 		cs->cs_ops = &zsops_null;
290 		cs->cs_brg_clk = PCLK / 16;
291 
292 		zc = (channel == 0) ? &zsd->zs_chan_a : &zsd->zs_chan_b;
293 
294 		zsc_args.consdev = NULL;
295 		zsc_args.hwflags = zs_console_flags(zsc->zsc_promunit,
296 						    zsc->zsc_node,
297 						    channel);
298 
299 		if (zsc_args.hwflags & ZS_HWFLAG_CONSOLE) {
300 			zsc_args.hwflags |= ZS_HWFLAG_USE_CONSDEV;
301 			zsc_args.consdev = &zs_consdev;
302 		}
303 
304 		if ((zsc_args.hwflags & ZS_HWFLAG_CONSOLE_INPUT) != 0) {
305 			zs_conschan_get = zc;
306 		}
307 		if ((zsc_args.hwflags & ZS_HWFLAG_CONSOLE_OUTPUT) != 0) {
308 			zs_conschan_put = zc;
309 		}
310 
311 		/* Children need to set cn_dev, etc */
312 		cs->cs_reg_csr  = &zc->zc_csr;
313 		cs->cs_reg_data = &zc->zc_data;
314 
315 		memcpy(cs->cs_creg, zs_init_reg, 16);
316 		memcpy(cs->cs_preg, zs_init_reg, 16);
317 
318 		/* XXX: Consult PROM properties for this?! */
319 		cs->cs_defspeed = zs_get_speed(cs);
320 		cs->cs_defcflag = zs_def_cflag;
321 
322 		/* Make these correspond to cs_defcflag (-crtscts) */
323 		cs->cs_rr0_dcd = ZSRR0_DCD;
324 		cs->cs_rr0_cts = 0;
325 		cs->cs_wr5_dtr = ZSWR5_DTR | ZSWR5_RTS;
326 		cs->cs_wr5_rts = 0;
327 
328 		/*
329 		 * Clear the master interrupt enable.
330 		 * The INTENA is common to both channels,
331 		 * so just do it on the A channel.
332 		 */
333 		if (channel == 0) {
334 			zs_write_reg(cs, 9, 0);
335 		}
336 
337 		/*
338 		 * Look for a child driver for this channel.
339 		 * The child attach will setup the hardware.
340 		 */
341 		child = config_found(&zsc->zsc_dev, (void *)&zsc_args,
342 		    zs_print);
343 		if (child == NULL) {
344 			/* No sub-driver.  Just reset it. */
345 			u_char reset = (channel == 0) ?
346 				ZSWR9_A_RESET : ZSWR9_B_RESET;
347 			s = splzs();
348 			zs_write_reg(cs,  9, reset);
349 			splx(s);
350 		}
351 #if (NKBD > 0) || (NMS > 0)
352 		/*
353 		 * If this was a zstty it has a keyboard
354 		 * property on it we need to attach the
355 		 * sunkbd and sunms line disciplines.
356 		 */
357 		if (child
358 		    && (device_is_a(child, "zstty"))
359 		    && (prom_getproplen(zsc->zsc_node, "keyboard") == 0)) {
360 			struct kbd_ms_tty_attach_args kma;
361 			struct tty *tp;
362 
363 			kma.kmta_tp = tp = zstty_get_tty_from_dev(child);
364 			kma.kmta_dev = tp->t_dev;
365 			kma.kmta_consdev = zsc_args.consdev;
366 
367 			/* Attach 'em if we got 'em. */
368 #if (NKBD > 0)
369 			if (channel == 0) {
370 				kma.kmta_name = "keyboard";
371 				config_found(child, (void *)&kma, NULL);
372 			}
373 #endif
374 #if (NMS > 0)
375 			if (channel == 1) {
376 				kma.kmta_name = "mouse";
377 				config_found(child, (void *)&kma, NULL);
378 			}
379 #endif
380 		}
381 #endif
382 	}
383 
384 	/*
385 	 * Now safe to install interrupt handlers.  Note the arguments
386 	 * to the interrupt handlers aren't used.  Note, we only do this
387 	 * once since both SCCs interrupt at the same level and vector.
388 	 */
389 	bus_intr_establish(zsc->zsc_bustag, pri, IPL_SERIAL, zshard, zsc);
390 	if (!(zsc->zsc_softintr = softintr_establish(softpri, zssoft, zsc)))
391 		panic("zsattach: could not establish soft interrupt");
392 
393 	evcnt_attach_dynamic(&zsc->zsc_intrcnt, EVCNT_TYPE_INTR, NULL,
394 	    zsc->zsc_dev.dv_xname, "intr");
395 
396 
397 	/*
398 	 * Set the master interrupt enable and interrupt vector.
399 	 * (common to both channels, do it on A)
400 	 */
401 	cs = zsc->zsc_cs[0];
402 	s = splhigh();
403 	/* interrupt vector */
404 	zs_write_reg(cs, 2, zs_init_reg[2]);
405 	/* master interrupt control (enable) */
406 	zs_write_reg(cs, 9, zs_init_reg[9]);
407 	splx(s);
408 
409 }
410 
411 static int
412 zs_print(void *aux, const char *name)
413 {
414 	struct zsc_attach_args *args = aux;
415 
416 	if (name != NULL)
417 		aprint_normal("%s: ", name);
418 
419 	if (args->channel != -1)
420 		aprint_normal(" channel %d", args->channel);
421 
422 	return (UNCONF);
423 }
424 
425 /* Deprecate this? */
426 static volatile int zssoftpending;
427 
428 static int
429 zshard(void *arg)
430 {
431 	struct zsc_softc *zsc = (struct zsc_softc *)arg;
432 	int rr3, rval;
433 
434 	rval = 0;
435 	while ((rr3 = zsc_intr_hard(zsc))) {
436 		/* Count up the interrupts. */
437 		rval |= rr3;
438 		zsc->zsc_intrcnt.ev_count++;
439 	}
440 	if (((zsc->zsc_cs[0] && zsc->zsc_cs[0]->cs_softreq) ||
441 	     (zsc->zsc_cs[1] && zsc->zsc_cs[1]->cs_softreq)) &&
442 	    zsc->zsc_softintr) {
443 		zssoftpending = PIL_TTY;
444 		softintr_schedule(zsc->zsc_softintr);
445 	}
446 	return (rval);
447 }
448 
449 int
450 zscheckintr(void *arg)
451 {
452 	struct zsc_softc *zsc;
453 	int unit, rval;
454 
455 	rval = 0;
456 	for (unit = 0; unit < zs_cd.cd_ndevs; unit++) {
457 
458 		zsc = zs_cd.cd_devs[unit];
459 		if (zsc == NULL)
460 			continue;
461 		rval = (zshard((void *)zsc) || rval);
462 	}
463 	return (rval);
464 }
465 
466 
467 /*
468  * We need this only for TTY_DEBUG purposes.
469  */
470 static void
471 zssoft(void *arg)
472 {
473 	struct zsc_softc *zsc = (struct zsc_softc *)arg;
474 	int s;
475 
476 	/* Make sure we call the tty layer at spltty. */
477 	s = spltty();
478 	zssoftpending = 0;
479 	(void)zsc_intr_soft(zsc);
480 #ifdef TTY_DEBUG
481 	{
482 		struct zstty_softc *zst0 = zsc->zsc_cs[0]->cs_private;
483 		struct zstty_softc *zst1 = zsc->zsc_cs[1]->cs_private;
484 		if (zst0->zst_overflows || zst1->zst_overflows ) {
485 			struct trapframe *frame = (struct trapframe *)arg;
486 
487 			printf("zs silo overflow from %p\n",
488 			       (long)frame->tf_pc);
489 		}
490 	}
491 #endif
492 	splx(s);
493 }
494 
495 
496 /*
497  * Compute the current baud rate given a ZS channel.
498  */
499 static int
500 zs_get_speed(struct zs_chanstate *cs)
501 {
502 	int tconst;
503 
504 	tconst = zs_read_reg(cs, 12);
505 	tconst |= zs_read_reg(cs, 13) << 8;
506 	return (TCONST_TO_BPS(cs->cs_brg_clk, tconst));
507 }
508 
509 /*
510  * MD functions for setting the baud rate and control modes.
511  */
512 int
513 zs_set_speed(struct zs_chanstate *cs, int bps /* bits per second */)
514 {
515 	int tconst, real_bps;
516 
517 	if (bps == 0)
518 		return (0);
519 
520 #ifdef	DIAGNOSTIC
521 	if (cs->cs_brg_clk == 0)
522 		panic("zs_set_speed");
523 #endif
524 
525 	tconst = BPS_TO_TCONST(cs->cs_brg_clk, bps);
526 	if (tconst < 0)
527 		return (EINVAL);
528 
529 	/* Convert back to make sure we can do it. */
530 	real_bps = TCONST_TO_BPS(cs->cs_brg_clk, tconst);
531 
532 	/* XXX - Allow some tolerance here? */
533 	if (real_bps != bps)
534 		return (EINVAL);
535 
536 	cs->cs_preg[12] = tconst;
537 	cs->cs_preg[13] = tconst >> 8;
538 
539 	/* Caller will stuff the pending registers. */
540 	return (0);
541 }
542 
543 int
544 zs_set_modes(struct zs_chanstate *cs, int cflag)
545 {
546 	int s;
547 
548 	/*
549 	 * Output hardware flow control on the chip is horrendous:
550 	 * if carrier detect drops, the receiver is disabled, and if
551 	 * CTS drops, the transmitter is stoped IN MID CHARACTER!
552 	 * Therefore, NEVER set the HFC bit, and instead use the
553 	 * status interrupt to detect CTS changes.
554 	 */
555 	s = splzs();
556 	cs->cs_rr0_pps = 0;
557 	if ((cflag & (CLOCAL | MDMBUF)) != 0) {
558 		cs->cs_rr0_dcd = 0;
559 		if ((cflag & MDMBUF) == 0)
560 			cs->cs_rr0_pps = ZSRR0_DCD;
561 	} else
562 		cs->cs_rr0_dcd = ZSRR0_DCD;
563 	if ((cflag & CRTSCTS) != 0) {
564 		cs->cs_wr5_dtr = ZSWR5_DTR;
565 		cs->cs_wr5_rts = ZSWR5_RTS;
566 		cs->cs_rr0_cts = ZSRR0_CTS;
567 	} else if ((cflag & CDTRCTS) != 0) {
568 		cs->cs_wr5_dtr = 0;
569 		cs->cs_wr5_rts = ZSWR5_DTR;
570 		cs->cs_rr0_cts = ZSRR0_CTS;
571 	} else if ((cflag & MDMBUF) != 0) {
572 		cs->cs_wr5_dtr = 0;
573 		cs->cs_wr5_rts = ZSWR5_DTR;
574 		cs->cs_rr0_cts = ZSRR0_DCD;
575 	} else {
576 		cs->cs_wr5_dtr = ZSWR5_DTR | ZSWR5_RTS;
577 		cs->cs_wr5_rts = 0;
578 		cs->cs_rr0_cts = 0;
579 	}
580 	splx(s);
581 
582 	/* Caller will stuff the pending registers. */
583 	return (0);
584 }
585 
586 
587 /*
588  * Read or write the chip with suitable delays.
589  */
590 
591 u_char
592 zs_read_reg(struct zs_chanstate *cs, u_char reg)
593 {
594 	u_char val;
595 
596 	*cs->cs_reg_csr = reg;
597 	ZS_DELAY();
598 	val = *cs->cs_reg_csr;
599 	ZS_DELAY();
600 	return (val);
601 }
602 
603 void
604 zs_write_reg(struct zs_chanstate *cs, u_char reg, u_char val)
605 {
606 	*cs->cs_reg_csr = reg;
607 	ZS_DELAY();
608 	*cs->cs_reg_csr = val;
609 	ZS_DELAY();
610 }
611 
612 u_char
613 zs_read_csr(struct zs_chanstate *cs)
614 {
615 	u_char val;
616 
617 	val = *cs->cs_reg_csr;
618 	ZS_DELAY();
619 	return (val);
620 }
621 
622 void
623 zs_write_csr(struct zs_chanstate *cs, u_char val)
624 {
625 	*cs->cs_reg_csr = val;
626 	ZS_DELAY();
627 }
628 
629 u_char
630 zs_read_data(struct zs_chanstate *cs)
631 {
632 	u_char val;
633 
634 	val = *cs->cs_reg_data;
635 	ZS_DELAY();
636 	return (val);
637 }
638 
639 void
640 zs_write_data(struct zs_chanstate *cs, u_char val)
641 {
642 	*cs->cs_reg_data = val;
643 	ZS_DELAY();
644 }
645 
646 /****************************************************************
647  * Console support functions (Sun specific!)
648  * Note: this code is allowed to know about the layout of
649  * the chip registers, and uses that to keep things simple.
650  * XXX - I think I like the mvme167 code better. -gwr
651  ****************************************************************/
652 
653 extern void Debugger(void);
654 
655 /*
656  * Handle user request to enter kernel debugger.
657  */
658 void
659 zs_abort(struct zs_chanstate *cs)
660 {
661 	volatile struct zschan *zc = zs_conschan_get;
662 	int rr0;
663 
664 	/* Wait for end of break to avoid PROM abort. */
665 	/* XXX - Limit the wait? */
666 	do {
667 		rr0 = zc->zc_csr;
668 		ZS_DELAY();
669 	} while (rr0 & ZSRR0_BREAK);
670 
671 #if defined(KGDB)
672 	zskgdb(cs);
673 #elif defined(DDB)
674 	{
675 		extern int db_active;
676 
677 		if (!db_active)
678 			Debugger();
679 		else
680 			/* Debugger is probably hozed */
681 			callrom();
682 	}
683 #else
684 	printf("stopping on keyboard abort\n");
685 	callrom();
686 #endif
687 }
688 
689 
690 /*
691  * Polled input char.
692  */
693 int
694 zs_getc(void *arg)
695 {
696 	volatile struct zschan *zc = arg;
697 	int s, c, rr0;
698 
699 	s = splhigh();
700 	/* Wait for a character to arrive. */
701 	do {
702 		rr0 = zc->zc_csr;
703 		ZS_DELAY();
704 	} while ((rr0 & ZSRR0_RX_READY) == 0);
705 
706 	c = zc->zc_data;
707 	ZS_DELAY();
708 	splx(s);
709 
710 	/*
711 	 * This is used by the kd driver to read scan codes,
712 	 * so don't translate '\r' ==> '\n' here...
713 	 */
714 	return (c);
715 }
716 
717 /*
718  * Polled output char.
719  */
720 void
721 zs_putc(void *arg, int c)
722 {
723 	volatile struct zschan *zc = arg;
724 	int s, rr0;
725 
726 	s = splhigh();
727 
728 	/* Wait for transmitter to become ready. */
729 	do {
730 		rr0 = zc->zc_csr;
731 		ZS_DELAY();
732 	} while ((rr0 & ZSRR0_TX_READY) == 0);
733 
734 	/*
735 	 * Send the next character.
736 	 * Now you'd think that this could be followed by a ZS_DELAY()
737 	 * just like all the other chip accesses, but it turns out that
738 	 * the `transmit-ready' interrupt isn't de-asserted until
739 	 * some period of time after the register write completes
740 	 * (more than a couple instructions).  So to avoid stray
741 	 * interrupts we put in the 2us delay regardless of CPU model.
742 	 */
743 	zc->zc_data = c;
744 	delay(2);
745 
746 	splx(s);
747 }
748 
749 /*****************************************************************/
750 
751 
752 
753 
754 /*
755  * Polled console input putchar.
756  */
757 static int
758 zscngetc(dev_t dev)
759 {
760 	return (zs_getc(zs_conschan_get));
761 }
762 
763 /*
764  * Polled console output putchar.
765  */
766 static void
767 zscnputc(dev_t dev, int c)
768 {
769 	zs_putc(zs_conschan_put, c);
770 }
771 
772 int swallow_zsintrs;
773 
774 static void
775 zscnpollc(dev_t dev, int on)
776 {
777 	/*
778 	 * Need to tell zs driver to acknowledge all interrupts or we get
779 	 * annoying spurious interrupt messages.  This is because mucking
780 	 * with spl() levels during polling does not prevent interrupts from
781 	 * being generated.
782 	 */
783 
784 	if (on) swallow_zsintrs++;
785 	else swallow_zsintrs--;
786 }
787 
788 int
789 zs_console_flags(int promunit, int node, int channel)
790 {
791 	int cookie, flags = 0;
792 	char buf[255];
793 
794 	/*
795 	 * We'll just do the OBP grovelling down here since that's
796 	 * the only type of firmware we support.
797 	 */
798 
799 	/* Default to channel 0 if there are no explicit prom args */
800 	cookie = 0;
801 	if (node == prom_instance_to_package(prom_stdin())) {
802 		if (prom_getoption("input-device", buf, sizeof buf) != 0 &&
803 		    strcmp("ttyb", buf) == 0)
804 			cookie = 1;
805 
806 		if (channel == cookie)
807 			flags |= ZS_HWFLAG_CONSOLE_INPUT;
808 	}
809 
810 	if (node == prom_instance_to_package(prom_stdout())) {
811 		if (prom_getoption("output-device", buf, sizeof buf) != 0 &&
812 		    strcmp("ttyb", buf) == 0)
813 			cookie = 1;
814 
815 		if (channel == cookie)
816 			flags |= ZS_HWFLAG_CONSOLE_OUTPUT;
817 	}
818 
819 	return (flags);
820 }
821 
822