xref: /netbsd-src/sys/dev/ic/z8530tty.c (revision de1dfb1250df962f1ff3a011772cf58e605aed11)
1 /*	$NetBSD: z8530tty.c,v 1.95 2004/06/20 18:07:35 thorpej Exp $	*/
2 
3 /*-
4  * Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998, 1999
5  *	Charles M. Hannum.  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 by Charles M. Hannum.
18  * 4. The name of the author may not be used to endorse or promote products
19  *    derived from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /*
34  * Copyright (c) 1992, 1993
35  *	The Regents of the University of California.  All rights reserved.
36  *
37  * This software was developed by the Computer Systems Engineering group
38  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
39  * contributed to Berkeley.
40  *
41  * All advertising materials mentioning features or use of this software
42  * must display the following acknowledgement:
43  *	This product includes software developed by the University of
44  *	California, Lawrence Berkeley Laboratory.
45  *
46  * Redistribution and use in source and binary forms, with or without
47  * modification, are permitted provided that the following conditions
48  * are met:
49  * 1. Redistributions of source code must retain the above copyright
50  *    notice, this list of conditions and the following disclaimer.
51  * 2. Redistributions in binary form must reproduce the above copyright
52  *    notice, this list of conditions and the following disclaimer in the
53  *    documentation and/or other materials provided with the distribution.
54  * 3. Neither the name of the University nor the names of its contributors
55  *    may be used to endorse or promote products derived from this software
56  *    without specific prior written permission.
57  *
58  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
59  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
60  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
61  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
62  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
63  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
64  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
65  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
66  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
67  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
68  * SUCH DAMAGE.
69  *
70  *	@(#)zs.c	8.1 (Berkeley) 7/19/93
71  */
72 
73 /*
74  * Copyright (c) 1994 Gordon W. Ross
75  *
76  * This software was developed by the Computer Systems Engineering group
77  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
78  * contributed to Berkeley.
79  *
80  * All advertising materials mentioning features or use of this software
81  * must display the following acknowledgement:
82  *	This product includes software developed by the University of
83  *	California, Lawrence Berkeley Laboratory.
84  *
85  * Redistribution and use in source and binary forms, with or without
86  * modification, are permitted provided that the following conditions
87  * are met:
88  * 1. Redistributions of source code must retain the above copyright
89  *    notice, this list of conditions and the following disclaimer.
90  * 2. Redistributions in binary form must reproduce the above copyright
91  *    notice, this list of conditions and the following disclaimer in the
92  *    documentation and/or other materials provided with the distribution.
93  * 3. All advertising materials mentioning features or use of this software
94  *    must display the following acknowledgement:
95  *	This product includes software developed by the University of
96  *	California, Berkeley and its contributors.
97  * 4. Neither the name of the University nor the names of its contributors
98  *    may be used to endorse or promote products derived from this software
99  *    without specific prior written permission.
100  *
101  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
102  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
103  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
104  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
105  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
106  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
107  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
108  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
109  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
110  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
111  * SUCH DAMAGE.
112  *
113  *	@(#)zs.c	8.1 (Berkeley) 7/19/93
114  */
115 
116 /*
117  * Zilog Z8530 Dual UART driver (tty interface)
118  *
119  * This is the "slave" driver that will be attached to
120  * the "zsc" driver for plain "tty" async. serial lines.
121  *
122  * Credits, history:
123  *
124  * The original version of this code was the sparc/dev/zs.c driver
125  * as distributed with the Berkeley 4.4 Lite release.  Since then,
126  * Gordon Ross reorganized the code into the current parent/child
127  * driver scheme, separating the Sun keyboard and mouse support
128  * into independent child drivers.
129  *
130  * RTS/CTS flow-control support was a collaboration of:
131  *	Gordon Ross <gwr@NetBSD.org>,
132  *	Bill Studenmund <wrstuden@loki.stanford.edu>
133  *	Ian Dall <Ian.Dall@dsto.defence.gov.au>
134  *
135  * The driver was massively overhauled in November 1997 by Charles Hannum,
136  * fixing *many* bugs, and substantially improving performance.
137  */
138 
139 #include <sys/cdefs.h>
140 __KERNEL_RCSID(0, "$NetBSD: z8530tty.c,v 1.95 2004/06/20 18:07:35 thorpej Exp $");
141 
142 #include "opt_kgdb.h"
143 #include "opt_ntp.h"
144 
145 #include <sys/param.h>
146 #include <sys/systm.h>
147 #include <sys/proc.h>
148 #include <sys/device.h>
149 #include <sys/conf.h>
150 #include <sys/file.h>
151 #include <sys/ioctl.h>
152 #include <sys/malloc.h>
153 #include <sys/timepps.h>
154 #include <sys/tty.h>
155 #include <sys/time.h>
156 #include <sys/kernel.h>
157 #include <sys/syslog.h>
158 
159 #include <dev/ic/z8530reg.h>
160 #include <machine/z8530var.h>
161 
162 #include <dev/cons.h>
163 
164 #include "locators.h"
165 
166 /*
167  * How many input characters we can buffer.
168  * The port-specific var.h may override this.
169  * Note: must be a power of two!
170  */
171 #ifndef	ZSTTY_RING_SIZE
172 #define	ZSTTY_RING_SIZE	2048
173 #endif
174 
175 static struct cnm_state zstty_cnm_state;
176 /*
177  * Make this an option variable one can patch.
178  * But be warned:  this must be a power of 2!
179  */
180 u_int zstty_rbuf_size = ZSTTY_RING_SIZE;
181 
182 /* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
183 u_int zstty_rbuf_hiwat = (ZSTTY_RING_SIZE * 1) / 4;
184 u_int zstty_rbuf_lowat = (ZSTTY_RING_SIZE * 3) / 4;
185 
186 static int zsppscap =
187 	PPS_TSFMT_TSPEC |
188 	PPS_CAPTUREASSERT |
189 	PPS_CAPTURECLEAR |
190 	PPS_OFFSETASSERT | PPS_OFFSETCLEAR;
191 
192 struct zstty_softc {
193 	struct	device zst_dev;		/* required first: base device */
194 	struct  tty *zst_tty;
195 	struct	zs_chanstate *zst_cs;
196 
197 	struct callout zst_diag_ch;
198 
199 	u_int zst_overflows,
200 	      zst_floods,
201 	      zst_errors;
202 
203 	int zst_hwflags,	/* see z8530var.h */
204 	    zst_swflags;	/* TIOCFLAG_SOFTCAR, ... <ttycom.h> */
205 
206 	u_int zst_r_hiwat,
207 	      zst_r_lowat;
208 	u_char *volatile zst_rbget,
209 	       *volatile zst_rbput;
210 	volatile u_int zst_rbavail;
211 	u_char *zst_rbuf,
212 	       *zst_ebuf;
213 
214 	/*
215 	 * The transmit byte count and address are used for pseudo-DMA
216 	 * output in the hardware interrupt code.  PDMA can be suspended
217 	 * to get pending changes done; heldtbc is used for this.  It can
218 	 * also be stopped for ^S; this sets TS_TTSTOP in tp->t_state.
219 	 */
220 	u_char *zst_tba;		/* transmit buffer address */
221 	u_int zst_tbc,			/* transmit byte count */
222 	      zst_heldtbc;		/* held tbc while xmission stopped */
223 
224 	/* Flags to communicate with zstty_softint() */
225 	volatile u_char zst_rx_flags,	/* receiver blocked */
226 #define	RX_TTY_BLOCKED		0x01
227 #define	RX_TTY_OVERFLOWED	0x02
228 #define	RX_IBUF_BLOCKED		0x04
229 #define	RX_IBUF_OVERFLOWED	0x08
230 #define	RX_ANY_BLOCK		0x0f
231 			zst_tx_busy,	/* working on an output chunk */
232 			zst_tx_done,	/* done with one output chunk */
233 			zst_tx_stopped,	/* H/W level stop (lost CTS) */
234 			zst_st_check,	/* got a status interrupt */
235 			zst_rx_ready;
236 
237 	/* PPS signal on DCD, with or without inkernel clock disciplining */
238 	u_char  zst_ppsmask;			/* pps signal mask */
239 	u_char  zst_ppsassert;			/* pps leading edge */
240 	u_char  zst_ppsclear;			/* pps trailing edge */
241 	pps_info_t ppsinfo;
242 	pps_params_t ppsparam;
243 };
244 
245 /* Macros to clear/set/test flags. */
246 #define SET(t, f)	(t) |= (f)
247 #define CLR(t, f)	(t) &= ~(f)
248 #define ISSET(t, f)	((t) & (f))
249 
250 /* Definition of the driver for autoconfig. */
251 static int	zstty_match(struct device *, struct cfdata *, void *);
252 static void	zstty_attach(struct device *, struct device *, void *);
253 
254 CFATTACH_DECL(zstty, sizeof(struct zstty_softc),
255     zstty_match, zstty_attach, NULL, NULL);
256 
257 extern struct cfdriver zstty_cd;
258 
259 dev_type_open(zsopen);
260 dev_type_close(zsclose);
261 dev_type_read(zsread);
262 dev_type_write(zswrite);
263 dev_type_ioctl(zsioctl);
264 dev_type_stop(zsstop);
265 dev_type_tty(zstty);
266 dev_type_poll(zspoll);
267 
268 const struct cdevsw zstty_cdevsw = {
269 	zsopen, zsclose, zsread, zswrite, zsioctl,
270 	zsstop, zstty, zspoll, nommap, ttykqfilter, D_TTY
271 };
272 
273 struct zsops zsops_tty;
274 
275 static void zs_shutdown __P((struct zstty_softc *));
276 static void	zsstart __P((struct tty *));
277 static int	zsparam __P((struct tty *, struct termios *));
278 static void zs_modem __P((struct zstty_softc *, int));
279 static void tiocm_to_zs __P((struct zstty_softc *, u_long, int));
280 static int  zs_to_tiocm __P((struct zstty_softc *));
281 static int    zshwiflow __P((struct tty *, int));
282 static void  zs_hwiflow __P((struct zstty_softc *));
283 static void zs_maskintr __P((struct zstty_softc *));
284 
285 /* Low-level routines. */
286 static void zstty_rxint   __P((struct zs_chanstate *));
287 static void zstty_stint   __P((struct zs_chanstate *, int));
288 static void zstty_txint   __P((struct zs_chanstate *));
289 static void zstty_softint __P((struct zs_chanstate *));
290 
291 #define	ZSUNIT(x)	(minor(x) & 0x7ffff)
292 #define	ZSDIALOUT(x)	(minor(x) & 0x80000)
293 
294 /*
295  * zstty_match: how is this zs channel configured?
296  */
297 int
298 zstty_match(parent, cf, aux)
299 	struct device *parent;
300 	struct cfdata *cf;
301 	void   *aux;
302 {
303 	struct zsc_attach_args *args = aux;
304 
305 	/* Exact match is better than wildcard. */
306 	if (cf->zsccf_channel == args->channel)
307 		return 2;
308 
309 	/* This driver accepts wildcard. */
310 	if (cf->zsccf_channel == ZSCCF_CHANNEL_DEFAULT)
311 		return 1;
312 
313 	return 0;
314 }
315 
316 void
317 zstty_attach(parent, self, aux)
318 	struct device *parent, *self;
319 	void   *aux;
320 
321 {
322 	struct zsc_softc *zsc = (void *) parent;
323 	struct zstty_softc *zst = (void *) self;
324 	struct cfdata *cf = self->dv_cfdata;
325 	struct zsc_attach_args *args = aux;
326 	struct zs_chanstate *cs;
327 	struct tty *tp;
328 	int channel, s, tty_unit;
329 	dev_t dev;
330 	char *i, *o;
331 	int dtr_on;
332 	int resetbit;
333 
334 	callout_init(&zst->zst_diag_ch);
335 	cn_init_magic(&zstty_cnm_state);
336 
337 	tty_unit = zst->zst_dev.dv_unit;
338 	channel = args->channel;
339 	cs = zsc->zsc_cs[channel];
340 	cs->cs_private = zst;
341 	cs->cs_ops = &zsops_tty;
342 
343 	zst->zst_cs = cs;
344 	zst->zst_swflags = cf->cf_flags;	/* softcar, etc. */
345 	zst->zst_hwflags = args->hwflags;
346 	dev = makedev(cdevsw_lookup_major(&zstty_cdevsw), tty_unit);
347 
348 	if (zst->zst_swflags)
349 		printf(" flags 0x%x", zst->zst_swflags);
350 
351 	/*
352 	 * Check whether we serve as a console device.
353 	 * XXX - split console input/output channels aren't
354 	 *	 supported yet on /dev/console
355 	 */
356 	i = o = NULL;
357 	if ((zst->zst_hwflags & ZS_HWFLAG_CONSOLE_INPUT) != 0) {
358 		i = "input";
359 		if ((args->hwflags & ZS_HWFLAG_USE_CONSDEV) != 0) {
360 			args->consdev->cn_dev = dev;
361 			cn_tab->cn_pollc = args->consdev->cn_pollc;
362 			cn_tab->cn_getc = args->consdev->cn_getc;
363 		}
364 		cn_tab->cn_dev = dev;
365 		/* Set console magic to BREAK */
366 		cn_set_magic("\047\001");
367 	}
368 	if ((zst->zst_hwflags & ZS_HWFLAG_CONSOLE_OUTPUT) != 0) {
369 		o = "output";
370 		if ((args->hwflags & ZS_HWFLAG_USE_CONSDEV) != 0) {
371 			cn_tab->cn_putc = args->consdev->cn_putc;
372 		}
373 		cn_tab->cn_dev = dev;
374 	}
375 	if (i != NULL || o != NULL)
376 		printf(" (console %s)", i ? (o ? "i/o" : i) : o);
377 
378 #ifdef KGDB
379 	if (zs_check_kgdb(cs, dev)) {
380 		/*
381 		 * Allow kgdb to "take over" this port.  Returns true
382 		 * if this serial port is in-use by kgdb.
383 		 */
384 		printf(" (kgdb)\n");
385 		/*
386 		 * This is the kgdb port (exclusive use)
387 		 * so skip the normal attach code.
388 		 */
389 		return;
390 	}
391 #endif
392 	printf("\n");
393 
394 	tp = ttymalloc();
395 	tp->t_dev = dev;
396 	tp->t_oproc = zsstart;
397 	tp->t_param = zsparam;
398 	tp->t_hwiflow = zshwiflow;
399 	tty_attach(tp);
400 
401 	zst->zst_tty = tp;
402 	zst->zst_rbuf = malloc(zstty_rbuf_size << 1, M_DEVBUF, M_WAITOK);
403 	zst->zst_ebuf = zst->zst_rbuf + (zstty_rbuf_size << 1);
404 	/* Disable the high water mark. */
405 	zst->zst_r_hiwat = 0;
406 	zst->zst_r_lowat = 0;
407 	zst->zst_rbget = zst->zst_rbput = zst->zst_rbuf;
408 	zst->zst_rbavail = zstty_rbuf_size;
409 
410 	/* if there are no enable/disable functions, assume the device
411 	   is always enabled */
412 	if (!cs->enable)
413 		cs->enabled = 1;
414 
415 	/*
416 	 * Hardware init
417 	 */
418 	dtr_on = 0;
419 	resetbit = 0;
420 	if (ISSET(zst->zst_hwflags, ZS_HWFLAG_CONSOLE)) {
421 		/* Call zsparam similar to open. */
422 		struct termios t;
423 
424 		/* Wait a while for previous console output to complete */
425 		DELAY(10000);
426 
427 		/* Setup the "new" parameters in t. */
428 		t.c_ispeed = 0;
429 		t.c_ospeed = cs->cs_defspeed;
430 		t.c_cflag = cs->cs_defcflag;
431 
432 		/*
433 		 * Turn on receiver and status interrupts.
434 		 * We defer the actual write of the register to zsparam(),
435 		 * but we must make sure status interrupts are turned on by
436 		 * the time zsparam() reads the initial rr0 state.
437 		 */
438 		SET(cs->cs_preg[1], ZSWR1_RIE | ZSWR1_SIE);
439 
440 		/* Make sure zsparam will see changes. */
441 		tp->t_ospeed = 0;
442 		(void) zsparam(tp, &t);
443 
444 		/* Make sure DTR is on now. */
445 		dtr_on = 1;
446 
447 	} else if (!ISSET(zst->zst_hwflags, ZS_HWFLAG_NORESET)) {
448 		/* Not the console; may need reset. */
449 		resetbit = (channel == 0) ? ZSWR9_A_RESET : ZSWR9_B_RESET;
450 	}
451 
452 	s = splzs();
453 	simple_lock(&cs->cs_lock);
454 	if (resetbit)
455 		zs_write_reg(cs, 9, resetbit);
456 	zs_modem(zst, dtr_on);
457 	simple_unlock(&cs->cs_lock);
458 	splx(s);
459 }
460 
461 
462 /*
463  * Return pointer to our tty.
464  */
465 struct tty *
466 zstty(dev)
467 	dev_t dev;
468 {
469 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
470 
471 	return (zst->zst_tty);
472 }
473 
474 
475 void
476 zs_shutdown(zst)
477 	struct zstty_softc *zst;
478 {
479 	struct zs_chanstate *cs = zst->zst_cs;
480 	struct tty *tp = zst->zst_tty;
481 	int s;
482 
483 	s = splzs();
484 	simple_lock(&cs->cs_lock);
485 
486 	/* If we were asserting flow control, then deassert it. */
487 	SET(zst->zst_rx_flags, RX_IBUF_BLOCKED);
488 	zs_hwiflow(zst);
489 
490 	/* Clear any break condition set with TIOCSBRK. */
491 	zs_break(cs, 0);
492 
493 	/* Turn off PPS capture on last close. */
494 	zst->zst_ppsmask = 0;
495 	zst->ppsparam.mode = 0;
496 
497 	/*
498 	 * Hang up if necessary.  Wait a bit, so the other side has time to
499 	 * notice even if we immediately open the port again.
500 	 */
501 	if (ISSET(tp->t_cflag, HUPCL)) {
502 		zs_modem(zst, 0);
503 		simple_unlock(&cs->cs_lock);
504 		splx(s);
505 		/*
506 		 * XXX -    another process is not prevented from opening
507 		 *	    the device during our sleep.
508 		 */
509 		(void) tsleep(cs, TTIPRI, ttclos, hz);
510 		/* Re-check state in case we were opened during our sleep */
511 		if (ISSET(tp->t_state, TS_ISOPEN) || tp->t_wopen != 0)
512 			return;
513 
514 		s = splzs();
515 		simple_lock(&cs->cs_lock);
516 	}
517 
518 	/* Turn off interrupts if not the console. */
519 	if (!ISSET(zst->zst_hwflags, ZS_HWFLAG_CONSOLE)) {
520 		CLR(cs->cs_preg[1], ZSWR1_RIE | ZSWR1_SIE);
521 		cs->cs_creg[1] = cs->cs_preg[1];
522 		zs_write_reg(cs, 1, cs->cs_creg[1]);
523 	}
524 
525 	/* Call the power management hook. */
526 	if (cs->disable) {
527 #ifdef DIAGNOSTIC
528 		if (!cs->enabled)
529 			panic("zs_shutdown: not enabled?");
530 #endif
531 		(*cs->disable)(zst->zst_cs);
532 	}
533 
534 	simple_unlock(&cs->cs_lock);
535 	splx(s);
536 }
537 
538 /*
539  * Open a zs serial (tty) port.
540  */
541 int
542 zsopen(dev, flags, mode, p)
543 	dev_t dev;
544 	int flags;
545 	int mode;
546 	struct proc *p;
547 {
548 	struct zstty_softc *zst;
549 	struct zs_chanstate *cs;
550 	struct tty *tp;
551 	int s, s2;
552 	int error;
553 
554 	zst = device_lookup(&zstty_cd, ZSUNIT(dev));
555 	if (zst == NULL)
556 		return (ENXIO);
557 
558 	tp = zst->zst_tty;
559 	cs = zst->zst_cs;
560 
561 	/* If KGDB took the line, then tp==NULL */
562 	if (tp == NULL)
563 		return (EBUSY);
564 
565 	if (ISSET(tp->t_state, TS_ISOPEN) &&
566 	    ISSET(tp->t_state, TS_XCLUDE) &&
567 	    p->p_ucred->cr_uid != 0)
568 		return (EBUSY);
569 
570 	s = spltty();
571 
572 	/*
573 	 * Do the following iff this is a first open.
574 	 */
575 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
576 		struct termios t;
577 
578 		tp->t_dev = dev;
579 
580 		/* Call the power management hook. */
581 		if (cs->enable) {
582 			if ((*cs->enable)(cs)) {
583 				splx(s);
584 				printf("%s: device enable failed\n",
585 			       	zst->zst_dev.dv_xname);
586 				return (EIO);
587 			}
588 		}
589 
590 		/*
591 		 * Initialize the termios status to the defaults.  Add in the
592 		 * sticky bits from TIOCSFLAGS.
593 		 */
594 		t.c_ispeed = 0;
595 		t.c_ospeed = cs->cs_defspeed;
596 		t.c_cflag = cs->cs_defcflag;
597 		if (ISSET(zst->zst_swflags, TIOCFLAG_CLOCAL))
598 			SET(t.c_cflag, CLOCAL);
599 		if (ISSET(zst->zst_swflags, TIOCFLAG_CRTSCTS))
600 			SET(t.c_cflag, CRTSCTS);
601 		if (ISSET(zst->zst_swflags, TIOCFLAG_CDTRCTS))
602 			SET(t.c_cflag, CDTRCTS);
603 		if (ISSET(zst->zst_swflags, TIOCFLAG_MDMBUF))
604 			SET(t.c_cflag, MDMBUF);
605 
606 		s2 = splzs();
607 		simple_lock(&cs->cs_lock);
608 
609 		/*
610 		 * Turn on receiver and status interrupts.
611 		 * We defer the actual write of the register to zsparam(),
612 		 * but we must make sure status interrupts are turned on by
613 		 * the time zsparam() reads the initial rr0 state.
614 		 */
615 		SET(cs->cs_preg[1], ZSWR1_RIE | ZSWR1_SIE);
616 
617 		/* Clear PPS capture state on first open. */
618 		zst->zst_ppsmask = 0;
619 		zst->ppsparam.mode = 0;
620 
621 		simple_unlock(&cs->cs_lock);
622 		splx(s2);
623 
624 		/* Make sure zsparam will see changes. */
625 		tp->t_ospeed = 0;
626 		(void) zsparam(tp, &t);
627 
628 		/*
629 		 * Note: zsparam has done: cflag, ispeed, ospeed
630 		 * so we just need to do: iflag, oflag, lflag, cc
631 		 * For "raw" mode, just leave all zeros.
632 		 */
633 		if (!ISSET(zst->zst_hwflags, ZS_HWFLAG_RAW)) {
634 			tp->t_iflag = TTYDEF_IFLAG;
635 			tp->t_oflag = TTYDEF_OFLAG;
636 			tp->t_lflag = TTYDEF_LFLAG;
637 		} else {
638 			tp->t_iflag = 0;
639 			tp->t_oflag = 0;
640 			tp->t_lflag = 0;
641 		}
642 		ttychars(tp);
643 		ttsetwater(tp);
644 
645 		s2 = splzs();
646 		simple_lock(&cs->cs_lock);
647 
648 		/*
649 		 * Turn on DTR.  We must always do this, even if carrier is not
650 		 * present, because otherwise we'd have to use TIOCSDTR
651 		 * immediately after setting CLOCAL, which applications do not
652 		 * expect.  We always assert DTR while the device is open
653 		 * unless explicitly requested to deassert it.
654 		 */
655 		zs_modem(zst, 1);
656 
657 		/* Clear the input ring, and unblock. */
658 		zst->zst_rbget = zst->zst_rbput = zst->zst_rbuf;
659 		zst->zst_rbavail = zstty_rbuf_size;
660 		zs_iflush(cs);
661 		CLR(zst->zst_rx_flags, RX_ANY_BLOCK);
662 		zs_hwiflow(zst);
663 
664 		simple_unlock(&cs->cs_lock);
665 		splx(s2);
666 	}
667 
668 	splx(s);
669 
670 	error = ttyopen(tp, ZSDIALOUT(dev), ISSET(flags, O_NONBLOCK));
671 	if (error)
672 		goto bad;
673 
674 	error = (*tp->t_linesw->l_open)(dev, tp);
675 	if (error)
676 		goto bad;
677 
678 	return (0);
679 
680 bad:
681 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
682 		/*
683 		 * We failed to open the device, and nobody else had it opened.
684 		 * Clean up the state as appropriate.
685 		 */
686 		zs_shutdown(zst);
687 	}
688 
689 	return (error);
690 }
691 
692 /*
693  * Close a zs serial port.
694  */
695 int
696 zsclose(dev, flags, mode, p)
697 	dev_t dev;
698 	int flags;
699 	int mode;
700 	struct proc *p;
701 {
702 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
703 	struct tty *tp = zst->zst_tty;
704 
705 	/* XXX This is for cons.c. */
706 	if (!ISSET(tp->t_state, TS_ISOPEN))
707 		return 0;
708 
709 	(*tp->t_linesw->l_close)(tp, flags);
710 	ttyclose(tp);
711 
712 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
713 		/*
714 		 * Although we got a last close, the device may still be in
715 		 * use; e.g. if this was the dialout node, and there are still
716 		 * processes waiting for carrier on the non-dialout node.
717 		 */
718 		zs_shutdown(zst);
719 	}
720 
721 	return (0);
722 }
723 
724 /*
725  * Read/write zs serial port.
726  */
727 int
728 zsread(dev, uio, flags)
729 	dev_t dev;
730 	struct uio *uio;
731 	int flags;
732 {
733 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
734 	struct tty *tp = zst->zst_tty;
735 
736 	return ((*tp->t_linesw->l_read)(tp, uio, flags));
737 }
738 
739 int
740 zswrite(dev, uio, flags)
741 	dev_t dev;
742 	struct uio *uio;
743 	int flags;
744 {
745 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
746 	struct tty *tp = zst->zst_tty;
747 
748 	return ((*tp->t_linesw->l_write)(tp, uio, flags));
749 }
750 
751 int
752 zspoll(dev, events, p)
753 	dev_t dev;
754 	int events;
755 	struct proc *p;
756 {
757 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
758 	struct tty *tp = zst->zst_tty;
759 
760 	return ((*tp->t_linesw->l_poll)(tp, events, p));
761 }
762 
763 int
764 zsioctl(dev, cmd, data, flag, p)
765 	dev_t dev;
766 	u_long cmd;
767 	caddr_t data;
768 	int flag;
769 	struct proc *p;
770 {
771 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
772 	struct zs_chanstate *cs = zst->zst_cs;
773 	struct tty *tp = zst->zst_tty;
774 	int error;
775 	int s;
776 
777 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, p);
778 	if (error != EPASSTHROUGH)
779 		return (error);
780 
781 	error = ttioctl(tp, cmd, data, flag, p);
782 	if (error != EPASSTHROUGH)
783 		return (error);
784 
785 #ifdef	ZS_MD_IOCTL
786 	error = ZS_MD_IOCTL(cs, cmd, data);
787 	if (error != EPASSTHROUGH)
788 		return (error);
789 #endif	/* ZS_MD_IOCTL */
790 
791 	error = 0;
792 
793 	s = splzs();
794 	simple_lock(&cs->cs_lock);
795 
796 	switch (cmd) {
797 	case TIOCSBRK:
798 		zs_break(cs, 1);
799 		break;
800 
801 	case TIOCCBRK:
802 		zs_break(cs, 0);
803 		break;
804 
805 	case TIOCGFLAGS:
806 		*(int *)data = zst->zst_swflags;
807 		break;
808 
809 	case TIOCSFLAGS:
810 		error = suser(p->p_ucred, &p->p_acflag);
811 		if (error)
812 			break;
813 		zst->zst_swflags = *(int *)data;
814 		break;
815 
816 	case TIOCSDTR:
817 		zs_modem(zst, 1);
818 		break;
819 
820 	case TIOCCDTR:
821 		zs_modem(zst, 0);
822 		break;
823 
824 	case TIOCMSET:
825 	case TIOCMBIS:
826 	case TIOCMBIC:
827 		tiocm_to_zs(zst, cmd, *(int *)data);
828 		break;
829 
830 	case TIOCMGET:
831 		*(int *)data = zs_to_tiocm(zst);
832 		break;
833 
834 	case PPS_IOC_CREATE:
835 		break;
836 
837 	case PPS_IOC_DESTROY:
838 		break;
839 
840 	case PPS_IOC_GETPARAMS: {
841 		pps_params_t *pp;
842 		pp = (pps_params_t *)data;
843 		*pp = zst->ppsparam;
844 		break;
845 	}
846 
847 	case PPS_IOC_SETPARAMS: {
848 		pps_params_t *pp;
849 		int mode;
850 		if (cs->cs_rr0_pps == 0) {
851 			error = EINVAL;
852 			break;
853 		}
854 		pp = (pps_params_t *)data;
855 		if (pp->mode & ~zsppscap) {
856 			error = EINVAL;
857 			break;
858 		}
859 		zst->ppsparam = *pp;
860 		/*
861 		 * compute masks from user-specified timestamp state.
862 		 */
863 		mode = zst->ppsparam.mode;
864 		switch (mode & PPS_CAPTUREBOTH) {
865 		case 0:
866 			zst->zst_ppsmask = 0;
867 			break;
868 
869 		case PPS_CAPTUREASSERT:
870 			zst->zst_ppsmask = ZSRR0_DCD;
871 			zst->zst_ppsassert = ZSRR0_DCD;
872 			zst->zst_ppsclear = -1;
873 			break;
874 
875 		case PPS_CAPTURECLEAR:
876 			zst->zst_ppsmask = ZSRR0_DCD;
877 			zst->zst_ppsassert = -1;
878 			zst->zst_ppsclear = 0;
879 			break;
880 
881 		case PPS_CAPTUREBOTH:
882 			zst->zst_ppsmask = ZSRR0_DCD;
883 			zst->zst_ppsassert = ZSRR0_DCD;
884 			zst->zst_ppsclear = 0;
885 			break;
886 
887 		default:
888 			error = EINVAL;
889 			break;
890 		}
891 
892 		/*
893 		 * Now update interrupts.
894 		 */
895 		zs_maskintr(zst);
896 		/*
897 		 * If nothing is being transmitted, set up new current values,
898 		 * else mark them as pending.
899 		 */
900 		if (!cs->cs_heldchange) {
901 			if (zst->zst_tx_busy) {
902 				zst->zst_heldtbc = zst->zst_tbc;
903 				zst->zst_tbc = 0;
904 				cs->cs_heldchange = 1;
905 			} else
906 				zs_loadchannelregs(cs);
907 		}
908 
909 		break;
910 	}
911 
912 	case PPS_IOC_GETCAP:
913 		*(int *)data = zsppscap;
914 		break;
915 
916 	case PPS_IOC_FETCH: {
917 		pps_info_t *pi;
918 		pi = (pps_info_t *)data;
919 		*pi = zst->ppsinfo;
920 		break;
921 	}
922 
923 #ifdef PPS_SYNC
924 	case PPS_IOC_KCBIND: {
925 		int edge = (*(int *)data) & PPS_CAPTUREBOTH;
926 
927 		if (edge == 0) {
928 			/*
929 			 * remove binding for this source; ignore
930 			 * the request if this is not the current
931 			 * hardpps source
932 			 */
933 			if (pps_kc_hardpps_source == zst) {
934 				pps_kc_hardpps_source = NULL;
935 				pps_kc_hardpps_mode = 0;
936 			}
937 		} else {
938 			/*
939 			 * bind hardpps to this source, replacing any
940 			 * previously specified source or edges
941 			 */
942 			pps_kc_hardpps_source = zst;
943 			pps_kc_hardpps_mode = edge;
944 		}
945 		break;
946 	}
947 #endif /* PPS_SYNC */
948 
949 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
950 		if (cs->cs_rr0_pps == 0) {
951 			error = EINVAL;
952 			break;
953 		}
954 		/*
955 		 * Some GPS clocks models use the falling rather than
956 		 * rising edge as the on-the-second signal.
957 		 * The old API has no way to specify PPS polarity.
958 		 */
959 		zst->zst_ppsmask = ZSRR0_DCD;
960 #ifndef	PPS_TRAILING_EDGE
961 		zst->zst_ppsassert = ZSRR0_DCD;
962 		zst->zst_ppsclear = -1;
963 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
964 			&zst->ppsinfo.assert_timestamp);
965 #else
966 		zst->zst_ppsassert = -1;
967 		zst->zst_ppsclear = 01;
968 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
969 			&zst->ppsinfo.clear_timestamp);
970 #endif
971 		/*
972 		 * Now update interrupts.
973 		 */
974 		zs_maskintr(zst);
975 		/*
976 		 * If nothing is being transmitted, set up new current values,
977 		 * else mark them as pending.
978 		 */
979 		if (!cs->cs_heldchange) {
980 			if (zst->zst_tx_busy) {
981 				zst->zst_heldtbc = zst->zst_tbc;
982 				zst->zst_tbc = 0;
983 				cs->cs_heldchange = 1;
984 			} else
985 				zs_loadchannelregs(cs);
986 		}
987 
988 		break;
989 
990 	default:
991 		error = EPASSTHROUGH;
992 		break;
993 	}
994 
995 	simple_unlock(&cs->cs_lock);
996 	splx(s);
997 
998 	return (error);
999 }
1000 
1001 /*
1002  * Start or restart transmission.
1003  */
1004 static void
1005 zsstart(tp)
1006 	struct tty *tp;
1007 {
1008 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(tp->t_dev));
1009 	struct zs_chanstate *cs = zst->zst_cs;
1010 	int s;
1011 
1012 	s = spltty();
1013 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
1014 		goto out;
1015 	if (zst->zst_tx_stopped)
1016 		goto out;
1017 
1018 	if (tp->t_outq.c_cc <= tp->t_lowat) {
1019 		if (ISSET(tp->t_state, TS_ASLEEP)) {
1020 			CLR(tp->t_state, TS_ASLEEP);
1021 			wakeup((caddr_t)&tp->t_outq);
1022 		}
1023 		selwakeup(&tp->t_wsel);
1024 		if (tp->t_outq.c_cc == 0)
1025 			goto out;
1026 	}
1027 
1028 	/* Grab the first contiguous region of buffer space. */
1029 	{
1030 		u_char *tba;
1031 		int tbc;
1032 
1033 		tba = tp->t_outq.c_cf;
1034 		tbc = ndqb(&tp->t_outq, 0);
1035 
1036 		(void) splzs();
1037 		simple_lock(&cs->cs_lock);
1038 
1039 		zst->zst_tba = tba;
1040 		zst->zst_tbc = tbc;
1041 	}
1042 
1043 	SET(tp->t_state, TS_BUSY);
1044 	zst->zst_tx_busy = 1;
1045 
1046 	/* Enable transmit completion interrupts if necessary. */
1047 	if (!ISSET(cs->cs_preg[1], ZSWR1_TIE)) {
1048 		SET(cs->cs_preg[1], ZSWR1_TIE);
1049 		cs->cs_creg[1] = cs->cs_preg[1];
1050 		zs_write_reg(cs, 1, cs->cs_creg[1]);
1051 	}
1052 
1053 	/* Output the first character of the contiguous buffer. */
1054 	{
1055 		zs_write_data(cs, *zst->zst_tba);
1056 		zst->zst_tbc--;
1057 		zst->zst_tba++;
1058 	}
1059 	simple_unlock(&cs->cs_lock);
1060 out:
1061 	splx(s);
1062 	return;
1063 }
1064 
1065 /*
1066  * Stop output, e.g., for ^S or output flush.
1067  */
1068 void
1069 zsstop(tp, flag)
1070 	struct tty *tp;
1071 	int flag;
1072 {
1073 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(tp->t_dev));
1074 	int s;
1075 
1076 	s = splzs();
1077 	if (ISSET(tp->t_state, TS_BUSY)) {
1078 		/* Stop transmitting at the next chunk. */
1079 		zst->zst_tbc = 0;
1080 		zst->zst_heldtbc = 0;
1081 		if (!ISSET(tp->t_state, TS_TTSTOP))
1082 			SET(tp->t_state, TS_FLUSH);
1083 	}
1084 	splx(s);
1085 }
1086 
1087 /*
1088  * Set ZS tty parameters from termios.
1089  * XXX - Should just copy the whole termios after
1090  * making sure all the changes could be done.
1091  */
1092 static int
1093 zsparam(tp, t)
1094 	struct tty *tp;
1095 	struct termios *t;
1096 {
1097 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(tp->t_dev));
1098 	struct zs_chanstate *cs = zst->zst_cs;
1099 	int ospeed;
1100 	tcflag_t cflag;
1101 	u_char tmp3, tmp4, tmp5;
1102 	int s, error;
1103 
1104 	ospeed = t->c_ospeed;
1105 	cflag = t->c_cflag;
1106 
1107 	/* Check requested parameters. */
1108 	if (ospeed < 0)
1109 		return (EINVAL);
1110 	if (t->c_ispeed && t->c_ispeed != ospeed)
1111 		return (EINVAL);
1112 
1113 	/*
1114 	 * For the console, always force CLOCAL and !HUPCL, so that the port
1115 	 * is always active.
1116 	 */
1117 	if (ISSET(zst->zst_swflags, TIOCFLAG_SOFTCAR) ||
1118 	    ISSET(zst->zst_hwflags, ZS_HWFLAG_CONSOLE)) {
1119 		SET(cflag, CLOCAL);
1120 		CLR(cflag, HUPCL);
1121 	}
1122 
1123 	/*
1124 	 * Only whack the UART when params change.
1125 	 * Some callers need to clear tp->t_ospeed
1126 	 * to make sure initialization gets done.
1127 	 */
1128 	if (tp->t_ospeed == ospeed &&
1129 	    tp->t_cflag == cflag)
1130 		return (0);
1131 
1132 	/*
1133 	 * Call MD functions to deal with changed
1134 	 * clock modes or H/W flow control modes.
1135 	 * The BRG divisor is set now. (reg 12,13)
1136 	 */
1137 	error = zs_set_speed(cs, ospeed);
1138 	if (error)
1139 		return (error);
1140 	error = zs_set_modes(cs, cflag);
1141 	if (error)
1142 		return (error);
1143 
1144 	/*
1145 	 * Block interrupts so that state will not
1146 	 * be altered until we are done setting it up.
1147 	 *
1148 	 * Initial values in cs_preg are set before
1149 	 * our attach routine is called.  The master
1150 	 * interrupt enable is handled by zsc.c
1151 	 *
1152 	 */
1153 	s = splzs();
1154 	simple_lock(&cs->cs_lock);
1155 
1156 	/*
1157 	 * Recalculate which status ints to enable.
1158 	 */
1159 	zs_maskintr(zst);
1160 
1161 	/* Recompute character size bits. */
1162 	tmp3 = cs->cs_preg[3];
1163 	tmp5 = cs->cs_preg[5];
1164 	CLR(tmp3, ZSWR3_RXSIZE);
1165 	CLR(tmp5, ZSWR5_TXSIZE);
1166 	switch (ISSET(cflag, CSIZE)) {
1167 	case CS5:
1168 		SET(tmp3, ZSWR3_RX_5);
1169 		SET(tmp5, ZSWR5_TX_5);
1170 		break;
1171 	case CS6:
1172 		SET(tmp3, ZSWR3_RX_6);
1173 		SET(tmp5, ZSWR5_TX_6);
1174 		break;
1175 	case CS7:
1176 		SET(tmp3, ZSWR3_RX_7);
1177 		SET(tmp5, ZSWR5_TX_7);
1178 		break;
1179 	case CS8:
1180 		SET(tmp3, ZSWR3_RX_8);
1181 		SET(tmp5, ZSWR5_TX_8);
1182 		break;
1183 	}
1184 	cs->cs_preg[3] = tmp3;
1185 	cs->cs_preg[5] = tmp5;
1186 
1187 	/*
1188 	 * Recompute the stop bits and parity bits.  Note that
1189 	 * zs_set_speed() may have set clock selection bits etc.
1190 	 * in wr4, so those must preserved.
1191 	 */
1192 	tmp4 = cs->cs_preg[4];
1193 	CLR(tmp4, ZSWR4_SBMASK | ZSWR4_PARMASK);
1194 	if (ISSET(cflag, CSTOPB))
1195 		SET(tmp4, ZSWR4_TWOSB);
1196 	else
1197 		SET(tmp4, ZSWR4_ONESB);
1198 	if (!ISSET(cflag, PARODD))
1199 		SET(tmp4, ZSWR4_EVENP);
1200 	if (ISSET(cflag, PARENB))
1201 		SET(tmp4, ZSWR4_PARENB);
1202 	cs->cs_preg[4] = tmp4;
1203 
1204 	/* And copy to tty. */
1205 	tp->t_ispeed = 0;
1206 	tp->t_ospeed = ospeed;
1207 	tp->t_cflag = cflag;
1208 
1209 	/*
1210 	 * If nothing is being transmitted, set up new current values,
1211 	 * else mark them as pending.
1212 	 */
1213 	if (!cs->cs_heldchange) {
1214 		if (zst->zst_tx_busy) {
1215 			zst->zst_heldtbc = zst->zst_tbc;
1216 			zst->zst_tbc = 0;
1217 			cs->cs_heldchange = 1;
1218 		} else
1219 			zs_loadchannelregs(cs);
1220 	}
1221 
1222 	/*
1223 	 * If hardware flow control is disabled, turn off the buffer water
1224 	 * marks and unblock any soft flow control state.  Otherwise, enable
1225 	 * the water marks.
1226 	 */
1227 	if (!ISSET(cflag, CHWFLOW)) {
1228 		zst->zst_r_hiwat = 0;
1229 		zst->zst_r_lowat = 0;
1230 		if (ISSET(zst->zst_rx_flags, RX_TTY_OVERFLOWED)) {
1231 			CLR(zst->zst_rx_flags, RX_TTY_OVERFLOWED);
1232 			zst->zst_rx_ready = 1;
1233 			cs->cs_softreq = 1;
1234 		}
1235 		if (ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
1236 			CLR(zst->zst_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
1237 			zs_hwiflow(zst);
1238 		}
1239 	} else {
1240 		zst->zst_r_hiwat = zstty_rbuf_hiwat;
1241 		zst->zst_r_lowat = zstty_rbuf_lowat;
1242 	}
1243 
1244 	/*
1245 	 * Force a recheck of the hardware carrier and flow control status,
1246 	 * since we may have changed which bits we're looking at.
1247 	 */
1248 	zstty_stint(cs, 1);
1249 
1250 	simple_unlock(&cs->cs_lock);
1251 	splx(s);
1252 
1253 	/*
1254 	 * If hardware flow control is disabled, unblock any hard flow control
1255 	 * state.
1256 	 */
1257 	if (!ISSET(cflag, CHWFLOW)) {
1258 		if (zst->zst_tx_stopped) {
1259 			zst->zst_tx_stopped = 0;
1260 			zsstart(tp);
1261 		}
1262 	}
1263 
1264 	zstty_softint(cs);
1265 
1266 	return (0);
1267 }
1268 
1269 /*
1270  * Compute interrupt enable bits and set in the pending bits. Called both
1271  * in zsparam() and when PPS (pulse per second timing) state changes.
1272  * Must be called at splzs().
1273  */
1274 static void
1275 zs_maskintr(zst)
1276 	struct zstty_softc *zst;
1277 {
1278 	struct zs_chanstate *cs = zst->zst_cs;
1279 	int tmp15;
1280 
1281 	cs->cs_rr0_mask = cs->cs_rr0_cts | cs->cs_rr0_dcd;
1282 	if (zst->zst_ppsmask != 0)
1283 		cs->cs_rr0_mask |= cs->cs_rr0_pps;
1284 	tmp15 = cs->cs_preg[15];
1285 	if (ISSET(cs->cs_rr0_mask, ZSRR0_DCD))
1286 		SET(tmp15, ZSWR15_DCD_IE);
1287 	else
1288 		CLR(tmp15, ZSWR15_DCD_IE);
1289 	if (ISSET(cs->cs_rr0_mask, ZSRR0_CTS))
1290 		SET(tmp15, ZSWR15_CTS_IE);
1291 	else
1292 		CLR(tmp15, ZSWR15_CTS_IE);
1293 	cs->cs_preg[15] = tmp15;
1294 }
1295 
1296 
1297 /*
1298  * Raise or lower modem control (DTR/RTS) signals.  If a character is
1299  * in transmission, the change is deferred.
1300  * Called at splzs() and with the channel lock held.
1301  */
1302 static void
1303 zs_modem(zst, onoff)
1304 	struct zstty_softc *zst;
1305 	int onoff;
1306 {
1307 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
1308 
1309 	if (cs->cs_wr5_dtr == 0)
1310 		return;
1311 
1312 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
1313 
1314 	if (onoff)
1315 		SET(ccs->cs_preg[5], cs->cs_wr5_dtr);
1316 	else
1317 		CLR(ccs->cs_preg[5], cs->cs_wr5_dtr);
1318 
1319 	if (!cs->cs_heldchange) {
1320 		if (zst->zst_tx_busy) {
1321 			zst->zst_heldtbc = zst->zst_tbc;
1322 			zst->zst_tbc = 0;
1323 			cs->cs_heldchange = 1;
1324 		} else
1325 			zs_loadchannelregs(cs);
1326 	}
1327 }
1328 
1329 /*
1330  * Set modem bits.
1331  * Called at splzs() and with the channel lock held.
1332  */
1333 static void
1334 tiocm_to_zs(zst, how, ttybits)
1335 	struct zstty_softc *zst;
1336 	u_long how;
1337 	int ttybits;
1338 {
1339 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
1340 	u_char zsbits;
1341 
1342 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
1343 
1344 	zsbits = 0;
1345 	if (ISSET(ttybits, TIOCM_DTR))
1346 		SET(zsbits, ZSWR5_DTR);
1347 	if (ISSET(ttybits, TIOCM_RTS))
1348 		SET(zsbits, ZSWR5_RTS);
1349 
1350 	switch (how) {
1351 	case TIOCMBIC:
1352 		CLR(ccs->cs_preg[5], zsbits);
1353 		break;
1354 
1355 	case TIOCMBIS:
1356 		SET(ccs->cs_preg[5], zsbits);
1357 		break;
1358 
1359 	case TIOCMSET:
1360 		CLR(ccs->cs_preg[5], ZSWR5_RTS | ZSWR5_DTR);
1361 		SET(ccs->cs_preg[5], zsbits);
1362 		break;
1363 	}
1364 
1365 	if (!cs->cs_heldchange) {
1366 		if (zst->zst_tx_busy) {
1367 			zst->zst_heldtbc = zst->zst_tbc;
1368 			zst->zst_tbc = 0;
1369 			cs->cs_heldchange = 1;
1370 		} else
1371 			zs_loadchannelregs(cs);
1372 	}
1373 }
1374 
1375 /*
1376  * Get modem bits.
1377  * Called at splzs() and with the channel lock held.
1378  */
1379 static int
1380 zs_to_tiocm(zst)
1381 	struct zstty_softc *zst;
1382 {
1383 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
1384 	u_char zsbits;
1385 	int ttybits = 0;
1386 
1387 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
1388 
1389 	zsbits = ccs->cs_preg[5];
1390 	if (ISSET(zsbits, ZSWR5_DTR))
1391 		SET(ttybits, TIOCM_DTR);
1392 	if (ISSET(zsbits, ZSWR5_RTS))
1393 		SET(ttybits, TIOCM_RTS);
1394 
1395 	zsbits = cs->cs_rr0;
1396 	if (ISSET(zsbits, ZSRR0_DCD))
1397 		SET(ttybits, TIOCM_CD);
1398 	if (ISSET(zsbits, ZSRR0_CTS))
1399 		SET(ttybits, TIOCM_CTS);
1400 
1401 	return (ttybits);
1402 }
1403 
1404 /*
1405  * Try to block or unblock input using hardware flow-control.
1406  * This is called by kern/tty.c if MDMBUF|CRTSCTS is set, and
1407  * if this function returns non-zero, the TS_TBLOCK flag will
1408  * be set or cleared according to the "block" arg passed.
1409  */
1410 int
1411 zshwiflow(tp, block)
1412 	struct tty *tp;
1413 	int block;
1414 {
1415 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(tp->t_dev));
1416 	struct zs_chanstate *cs = zst->zst_cs;
1417 	int s;
1418 
1419 	if (cs->cs_wr5_rts == 0)
1420 		return (0);
1421 
1422 	s = splzs();
1423 	simple_lock(&cs->cs_lock);
1424 	if (block) {
1425 		if (!ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED)) {
1426 			SET(zst->zst_rx_flags, RX_TTY_BLOCKED);
1427 			zs_hwiflow(zst);
1428 		}
1429 	} else {
1430 		if (ISSET(zst->zst_rx_flags, RX_TTY_OVERFLOWED)) {
1431 			CLR(zst->zst_rx_flags, RX_TTY_OVERFLOWED);
1432 			zst->zst_rx_ready = 1;
1433 			cs->cs_softreq = 1;
1434 		}
1435 		if (ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED)) {
1436 			CLR(zst->zst_rx_flags, RX_TTY_BLOCKED);
1437 			zs_hwiflow(zst);
1438 		}
1439 	}
1440 	simple_unlock(&cs->cs_lock);
1441 	splx(s);
1442 	return (1);
1443 }
1444 
1445 /*
1446  * Internal version of zshwiflow
1447  * Called at splzs() and with the channel lock held.
1448  */
1449 static void
1450 zs_hwiflow(zst)
1451 	struct zstty_softc *zst;
1452 {
1453 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
1454 
1455 	if (cs->cs_wr5_rts == 0)
1456 		return;
1457 
1458 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
1459 
1460 	if (ISSET(zst->zst_rx_flags, RX_ANY_BLOCK)) {
1461 		CLR(ccs->cs_preg[5], cs->cs_wr5_rts);
1462 		CLR(ccs->cs_creg[5], cs->cs_wr5_rts);
1463 	} else {
1464 		SET(ccs->cs_preg[5], cs->cs_wr5_rts);
1465 		SET(ccs->cs_creg[5], cs->cs_wr5_rts);
1466 	}
1467 	zs_write_reg(ccs, 5, ccs->cs_creg[5]);
1468 }
1469 
1470 
1471 /****************************************************************
1472  * Interface to the lower layer (zscc)
1473  ****************************************************************/
1474 
1475 #define	integrate	static inline
1476 integrate void zstty_rxsoft __P((struct zstty_softc *, struct tty *));
1477 integrate void zstty_txsoft __P((struct zstty_softc *, struct tty *));
1478 integrate void zstty_stsoft __P((struct zstty_softc *, struct tty *));
1479 static void zstty_diag __P((void *));
1480 
1481 /*
1482  * Receiver Ready interrupt.
1483  * Called at splzs() and with the channel lock held.
1484  */
1485 static void
1486 zstty_rxint(cs)
1487 	struct zs_chanstate *cs;
1488 {
1489 	struct zstty_softc *zst = cs->cs_private;
1490 	u_char *put, *end;
1491 	u_int cc;
1492 	u_char rr0, rr1, c;
1493 
1494 	end = zst->zst_ebuf;
1495 	put = zst->zst_rbput;
1496 	cc = zst->zst_rbavail;
1497 
1498 	while (cc > 0) {
1499 		/*
1500 		 * First read the status, because reading the received char
1501 		 * destroys the status of this char.
1502 		 */
1503 		rr1 = zs_read_reg(cs, 1);
1504 		c = zs_read_data(cs);
1505 
1506 		if (ISSET(rr1, ZSRR1_FE | ZSRR1_DO | ZSRR1_PE)) {
1507 			/* Clear the receive error. */
1508 			zs_write_csr(cs, ZSWR0_RESET_ERRORS);
1509 		}
1510 
1511 		cn_check_magic(zst->zst_tty->t_dev, c, zstty_cnm_state);
1512 		put[0] = c;
1513 		put[1] = rr1;
1514 		put += 2;
1515 		if (put >= end)
1516 			put = zst->zst_rbuf;
1517 		cc--;
1518 
1519 		rr0 = zs_read_csr(cs);
1520 		if (!ISSET(rr0, ZSRR0_RX_READY))
1521 			break;
1522 	}
1523 
1524 	/*
1525 	 * Current string of incoming characters ended because
1526 	 * no more data was available or we ran out of space.
1527 	 * Schedule a receive event if any data was received.
1528 	 * If we're out of space, turn off receive interrupts.
1529 	 */
1530 	zst->zst_rbput = put;
1531 	zst->zst_rbavail = cc;
1532 	if (!ISSET(zst->zst_rx_flags, RX_TTY_OVERFLOWED)) {
1533 		zst->zst_rx_ready = 1;
1534 		cs->cs_softreq = 1;
1535 	}
1536 
1537 	/*
1538 	 * See if we are in danger of overflowing a buffer. If
1539 	 * so, use hardware flow control to ease the pressure.
1540 	 */
1541 	if (!ISSET(zst->zst_rx_flags, RX_IBUF_BLOCKED) &&
1542 	    cc < zst->zst_r_hiwat) {
1543 		SET(zst->zst_rx_flags, RX_IBUF_BLOCKED);
1544 		zs_hwiflow(zst);
1545 	}
1546 
1547 	/*
1548 	 * If we're out of space, disable receive interrupts
1549 	 * until the queue has drained a bit.
1550 	 */
1551 	if (!cc) {
1552 		SET(zst->zst_rx_flags, RX_IBUF_OVERFLOWED);
1553 		CLR(cs->cs_preg[1], ZSWR1_RIE);
1554 		cs->cs_creg[1] = cs->cs_preg[1];
1555 		zs_write_reg(cs, 1, cs->cs_creg[1]);
1556 	}
1557 
1558 #if 0
1559 	printf("%xH%04d\n", zst->zst_rx_flags, zst->zst_rbavail);
1560 #endif
1561 }
1562 
1563 /*
1564  * Transmitter Ready interrupt.
1565  * Called at splzs() and with the channel lock held.
1566  */
1567 static void
1568 zstty_txint(cs)
1569 	struct zs_chanstate *cs;
1570 {
1571 	struct zstty_softc *zst = cs->cs_private;
1572 
1573 	/*
1574 	 * If we've delayed a parameter change, do it now, and restart
1575 	 * output.
1576 	 */
1577 	if (cs->cs_heldchange) {
1578 		zs_loadchannelregs(cs);
1579 		cs->cs_heldchange = 0;
1580 		zst->zst_tbc = zst->zst_heldtbc;
1581 		zst->zst_heldtbc = 0;
1582 	}
1583 
1584 	/* Output the next character in the buffer, if any. */
1585 	if (zst->zst_tbc > 0) {
1586 		zs_write_data(cs, *zst->zst_tba);
1587 		zst->zst_tbc--;
1588 		zst->zst_tba++;
1589 	} else {
1590 		/* Disable transmit completion interrupts if necessary. */
1591 		if (ISSET(cs->cs_preg[1], ZSWR1_TIE)) {
1592 			CLR(cs->cs_preg[1], ZSWR1_TIE);
1593 			cs->cs_creg[1] = cs->cs_preg[1];
1594 			zs_write_reg(cs, 1, cs->cs_creg[1]);
1595 		}
1596 		if (zst->zst_tx_busy) {
1597 			zst->zst_tx_busy = 0;
1598 			zst->zst_tx_done = 1;
1599 			cs->cs_softreq = 1;
1600 		}
1601 	}
1602 }
1603 
1604 /*
1605  * Status Change interrupt.
1606  * Called at splzs() and with the channel lock held.
1607  */
1608 static void
1609 zstty_stint(cs, force)
1610 	struct zs_chanstate *cs;
1611 	int force;
1612 {
1613 	struct zstty_softc *zst = cs->cs_private;
1614 	u_char rr0, delta;
1615 
1616 	rr0 = zs_read_csr(cs);
1617 	zs_write_csr(cs, ZSWR0_RESET_STATUS);
1618 
1619 	/*
1620 	 * Check here for console break, so that we can abort
1621 	 * even when interrupts are locking up the machine.
1622 	 */
1623 	if (ISSET(rr0, ZSRR0_BREAK))
1624 		cn_check_magic(zst->zst_tty->t_dev, CNC_BREAK, zstty_cnm_state);
1625 
1626 	if (!force)
1627 		delta = rr0 ^ cs->cs_rr0;
1628 	else
1629 		delta = cs->cs_rr0_mask;
1630 	cs->cs_rr0 = rr0;
1631 
1632 	if (ISSET(delta, cs->cs_rr0_mask)) {
1633 		SET(cs->cs_rr0_delta, delta);
1634 
1635 		/*
1636 		 * Pulse-per-second clock signal on edge of DCD?
1637 		 */
1638 		if (ISSET(delta, zst->zst_ppsmask)) {
1639 			struct timeval tv;
1640 			if (ISSET(rr0, zst->zst_ppsmask) == zst->zst_ppsassert) {
1641 				/* XXX nanotime() */
1642 				microtime(&tv);
1643 				TIMEVAL_TO_TIMESPEC(&tv,
1644 					&zst->ppsinfo.assert_timestamp);
1645 				if (zst->ppsparam.mode & PPS_OFFSETASSERT) {
1646 					timespecadd(&zst->ppsinfo.assert_timestamp,
1647 					    &zst->ppsparam.assert_offset,
1648 					    &zst->ppsinfo.assert_timestamp);
1649 				}
1650 
1651 #ifdef PPS_SYNC
1652 				if (pps_kc_hardpps_source == zst &&
1653 				    pps_kc_hardpps_mode & PPS_CAPTUREASSERT) {
1654 					hardpps(&tv, tv.tv_usec);
1655 				}
1656 #endif
1657 				zst->ppsinfo.assert_sequence++;
1658 				zst->ppsinfo.current_mode = zst->ppsparam.mode;
1659 			} else if (ISSET(rr0, zst->zst_ppsmask) ==
1660 						zst->zst_ppsclear) {
1661 				/* XXX nanotime() */
1662 				microtime(&tv);
1663 				TIMEVAL_TO_TIMESPEC(&tv,
1664 					&zst->ppsinfo.clear_timestamp);
1665 				if (zst->ppsparam.mode & PPS_OFFSETCLEAR) {
1666 					timespecadd(&zst->ppsinfo.clear_timestamp,
1667 						&zst->ppsparam.clear_offset,
1668 						&zst->ppsinfo.clear_timestamp);
1669 				}
1670 
1671 #ifdef PPS_SYNC
1672 				if (pps_kc_hardpps_source == zst &&
1673 				    pps_kc_hardpps_mode & PPS_CAPTURECLEAR) {
1674 					hardpps(&tv, tv.tv_usec);
1675 				}
1676 #endif
1677 				zst->ppsinfo.clear_sequence++;
1678 				zst->ppsinfo.current_mode = zst->ppsparam.mode;
1679 			}
1680 		}
1681 
1682 		/*
1683 		 * Stop output immediately if we lose the output
1684 		 * flow control signal or carrier detect.
1685 		 */
1686 		if (ISSET(~rr0, cs->cs_rr0_mask)) {
1687 			zst->zst_tbc = 0;
1688 			zst->zst_heldtbc = 0;
1689 		}
1690 
1691 		zst->zst_st_check = 1;
1692 		cs->cs_softreq = 1;
1693 	}
1694 }
1695 
1696 void
1697 zstty_diag(arg)
1698 	void *arg;
1699 {
1700 	struct zstty_softc *zst = arg;
1701 	int overflows, floods;
1702 	int s;
1703 
1704 	s = splzs();
1705 	overflows = zst->zst_overflows;
1706 	zst->zst_overflows = 0;
1707 	floods = zst->zst_floods;
1708 	zst->zst_floods = 0;
1709 	zst->zst_errors = 0;
1710 	splx(s);
1711 
1712 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
1713 	    zst->zst_dev.dv_xname,
1714 	    overflows, overflows == 1 ? "" : "s",
1715 	    floods, floods == 1 ? "" : "s");
1716 }
1717 
1718 integrate void
1719 zstty_rxsoft(zst, tp)
1720 	struct zstty_softc *zst;
1721 	struct tty *tp;
1722 {
1723 	struct zs_chanstate *cs = zst->zst_cs;
1724 	int (*rint) __P((int c, struct tty *tp)) = tp->t_linesw->l_rint;
1725 	u_char *get, *end;
1726 	u_int cc, scc;
1727 	u_char rr1;
1728 	int code;
1729 	int s;
1730 
1731 	end = zst->zst_ebuf;
1732 	get = zst->zst_rbget;
1733 	scc = cc = zstty_rbuf_size - zst->zst_rbavail;
1734 
1735 	if (cc == zstty_rbuf_size) {
1736 		zst->zst_floods++;
1737 		if (zst->zst_errors++ == 0)
1738 			callout_reset(&zst->zst_diag_ch, 60 * hz,
1739 			    zstty_diag, zst);
1740 	}
1741 
1742 	/* If not yet open, drop the entire buffer content here */
1743 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
1744 		get += cc << 1;
1745 		if (get >= end)
1746 			get -= zstty_rbuf_size << 1;
1747 		cc = 0;
1748 	}
1749 	while (cc) {
1750 		code = get[0];
1751 		rr1 = get[1];
1752 		if (ISSET(rr1, ZSRR1_DO | ZSRR1_FE | ZSRR1_PE)) {
1753 			if (ISSET(rr1, ZSRR1_DO)) {
1754 				zst->zst_overflows++;
1755 				if (zst->zst_errors++ == 0)
1756 					callout_reset(&zst->zst_diag_ch,
1757 					    60 * hz, zstty_diag, zst);
1758 			}
1759 			if (ISSET(rr1, ZSRR1_FE))
1760 				SET(code, TTY_FE);
1761 			if (ISSET(rr1, ZSRR1_PE))
1762 				SET(code, TTY_PE);
1763 		}
1764 		if ((*rint)(code, tp) == -1) {
1765 			/*
1766 			 * The line discipline's buffer is out of space.
1767 			 */
1768 			if (!ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED)) {
1769 				/*
1770 				 * We're either not using flow control, or the
1771 				 * line discipline didn't tell us to block for
1772 				 * some reason.  Either way, we have no way to
1773 				 * know when there's more space available, so
1774 				 * just drop the rest of the data.
1775 				 */
1776 				get += cc << 1;
1777 				if (get >= end)
1778 					get -= zstty_rbuf_size << 1;
1779 				cc = 0;
1780 			} else {
1781 				/*
1782 				 * Don't schedule any more receive processing
1783 				 * until the line discipline tells us there's
1784 				 * space available (through comhwiflow()).
1785 				 * Leave the rest of the data in the input
1786 				 * buffer.
1787 				 */
1788 				SET(zst->zst_rx_flags, RX_TTY_OVERFLOWED);
1789 			}
1790 			break;
1791 		}
1792 		get += 2;
1793 		if (get >= end)
1794 			get = zst->zst_rbuf;
1795 		cc--;
1796 	}
1797 
1798 	if (cc != scc) {
1799 		zst->zst_rbget = get;
1800 		s = splzs();
1801 		simple_lock(&cs->cs_lock);
1802 		cc = zst->zst_rbavail += scc - cc;
1803 		/* Buffers should be ok again, release possible block. */
1804 		if (cc >= zst->zst_r_lowat) {
1805 			if (ISSET(zst->zst_rx_flags, RX_IBUF_OVERFLOWED)) {
1806 				CLR(zst->zst_rx_flags, RX_IBUF_OVERFLOWED);
1807 				SET(cs->cs_preg[1], ZSWR1_RIE);
1808 				cs->cs_creg[1] = cs->cs_preg[1];
1809 				zs_write_reg(cs, 1, cs->cs_creg[1]);
1810 			}
1811 			if (ISSET(zst->zst_rx_flags, RX_IBUF_BLOCKED)) {
1812 				CLR(zst->zst_rx_flags, RX_IBUF_BLOCKED);
1813 				zs_hwiflow(zst);
1814 			}
1815 		}
1816 		simple_unlock(&cs->cs_lock);
1817 		splx(s);
1818 	}
1819 
1820 #if 0
1821 	printf("%xS%04d\n", zst->zst_rx_flags, zst->zst_rbavail);
1822 #endif
1823 }
1824 
1825 integrate void
1826 zstty_txsoft(zst, tp)
1827 	struct zstty_softc *zst;
1828 	struct tty *tp;
1829 {
1830 	struct zs_chanstate *cs = zst->zst_cs;
1831 	int s;
1832 
1833 	s = splzs();
1834 	simple_lock(&cs->cs_lock);
1835 	CLR(tp->t_state, TS_BUSY);
1836 	if (ISSET(tp->t_state, TS_FLUSH))
1837 		CLR(tp->t_state, TS_FLUSH);
1838 	else
1839 		ndflush(&tp->t_outq, (int)(zst->zst_tba - tp->t_outq.c_cf));
1840 	simple_unlock(&cs->cs_lock);
1841 	splx(s);
1842 	(*tp->t_linesw->l_start)(tp);
1843 }
1844 
1845 integrate void
1846 zstty_stsoft(zst, tp)
1847 	struct zstty_softc *zst;
1848 	struct tty *tp;
1849 {
1850 	struct zs_chanstate *cs = zst->zst_cs;
1851 	u_char rr0, delta;
1852 	int s;
1853 
1854 	s = splzs();
1855 	simple_lock(&cs->cs_lock);
1856 	rr0 = cs->cs_rr0;
1857 	delta = cs->cs_rr0_delta;
1858 	cs->cs_rr0_delta = 0;
1859 	simple_unlock(&cs->cs_lock);
1860 	splx(s);
1861 
1862 	if (ISSET(delta, cs->cs_rr0_dcd)) {
1863 		/*
1864 		 * Inform the tty layer that carrier detect changed.
1865 		 */
1866 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(rr0, ZSRR0_DCD));
1867 	}
1868 
1869 	if (ISSET(delta, cs->cs_rr0_cts)) {
1870 		/* Block or unblock output according to flow control. */
1871 		if (ISSET(rr0, cs->cs_rr0_cts)) {
1872 			zst->zst_tx_stopped = 0;
1873 			(*tp->t_linesw->l_start)(tp);
1874 		} else {
1875 			zst->zst_tx_stopped = 1;
1876 		}
1877 	}
1878 }
1879 
1880 /*
1881  * Software interrupt.  Called at zssoft
1882  *
1883  * The main job to be done here is to empty the input ring
1884  * by passing its contents up to the tty layer.  The ring is
1885  * always emptied during this operation, therefore the ring
1886  * must not be larger than the space after "high water" in
1887  * the tty layer, or the tty layer might drop our input.
1888  *
1889  * Note: an "input blockage" condition is assumed to exist if
1890  * EITHER the TS_TBLOCK flag or zst_rx_blocked flag is set.
1891  */
1892 static void
1893 zstty_softint(cs)
1894 	struct zs_chanstate *cs;
1895 {
1896 	struct zstty_softc *zst = cs->cs_private;
1897 	struct tty *tp = zst->zst_tty;
1898 	int s;
1899 
1900 	s = spltty();
1901 
1902 	if (zst->zst_rx_ready) {
1903 		zst->zst_rx_ready = 0;
1904 		zstty_rxsoft(zst, tp);
1905 	}
1906 
1907 	if (zst->zst_st_check) {
1908 		zst->zst_st_check = 0;
1909 		zstty_stsoft(zst, tp);
1910 	}
1911 
1912 	if (zst->zst_tx_done) {
1913 		zst->zst_tx_done = 0;
1914 		zstty_txsoft(zst, tp);
1915 	}
1916 
1917 	splx(s);
1918 }
1919 
1920 struct zsops zsops_tty = {
1921 	zstty_rxint,	/* receive char available */
1922 	zstty_stint,	/* external/status */
1923 	zstty_txint,	/* xmit buffer empty */
1924 	zstty_softint,	/* process software interrupt */
1925 };
1926