xref: /netbsd-src/sys/dev/ic/z8530tty.c (revision b7b7574d3bf8eeb51a1fa3977b59142ec6434a55)
1 /*	$NetBSD: z8530tty.c,v 1.129 2014/03/16 05:20:27 dholland 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 1.129 2014/03/16 05:20:27 dholland 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 #include <sys/kauth.h>
159 
160 #include <dev/ic/z8530reg.h>
161 #include <machine/z8530var.h>
162 
163 #include <dev/cons.h>
164 
165 #include "ioconf.h"
166 #include "locators.h"
167 
168 /*
169  * How many input characters we can buffer.
170  * The port-specific var.h may override this.
171  * Note: must be a power of two!
172  */
173 #ifndef	ZSTTY_RING_SIZE
174 #define	ZSTTY_RING_SIZE	2048
175 #endif
176 
177 static struct cnm_state zstty_cnm_state;
178 /*
179  * Make this an option variable one can patch.
180  * But be warned:  this must be a power of 2!
181  */
182 u_int zstty_rbuf_size = ZSTTY_RING_SIZE;
183 
184 /* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
185 u_int zstty_rbuf_hiwat = (ZSTTY_RING_SIZE * 1) / 4;
186 u_int zstty_rbuf_lowat = (ZSTTY_RING_SIZE * 3) / 4;
187 
188 struct zstty_softc {
189 	device_t zst_dev;		/* required first: base device */
190 	struct  tty *zst_tty;
191 	struct	zs_chanstate *zst_cs;
192 
193 	struct callout zst_diag_ch;
194 
195 	u_int zst_overflows,
196 	      zst_floods,
197 	      zst_errors;
198 
199 	int zst_hwflags,	/* see z8530var.h */
200 	    zst_swflags;	/* TIOCFLAG_SOFTCAR, ... <ttycom.h> */
201 
202 	u_int zst_r_hiwat,
203 	      zst_r_lowat;
204 	uint8_t *volatile zst_rbget,
205 	        *volatile zst_rbput;
206 	volatile u_int zst_rbavail;
207 	uint8_t *zst_rbuf,
208 	        *zst_ebuf;
209 
210 	/*
211 	 * The transmit byte count and address are used for pseudo-DMA
212 	 * output in the hardware interrupt code.  PDMA can be suspended
213 	 * to get pending changes done; heldtbc is used for this.  It can
214 	 * also be stopped for ^S; this sets TS_TTSTOP in tp->t_state.
215 	 */
216 	uint8_t *zst_tba;		/* transmit buffer address */
217 	u_int zst_tbc,			/* transmit byte count */
218 	      zst_heldtbc;		/* held tbc while xmission stopped */
219 
220 	/* Flags to communicate with zstty_softint() */
221 	volatile uint8_t zst_rx_flags,	/* receiver blocked */
222 #define	RX_TTY_BLOCKED		0x01
223 #define	RX_TTY_OVERFLOWED	0x02
224 #define	RX_IBUF_BLOCKED		0x04
225 #define	RX_IBUF_OVERFLOWED	0x08
226 #define	RX_ANY_BLOCK		0x0f
227 			zst_tx_busy,	/* working on an output chunk */
228 			zst_tx_done,	/* done with one output chunk */
229 			zst_tx_stopped,	/* H/W level stop (lost CTS) */
230 			zst_st_check,	/* got a status interrupt */
231 			zst_rx_ready;
232 
233 	/* PPS signal on DCD, with or without inkernel clock disciplining */
234 	uint8_t  zst_ppsmask;			/* pps signal mask */
235 	struct pps_state zst_pps_state;
236 };
237 
238 /* Definition of the driver for autoconfig. */
239 static int	zstty_match(device_t, cfdata_t, void *);
240 static void	zstty_attach(device_t, device_t, void *);
241 
242 CFATTACH_DECL_NEW(zstty, sizeof(struct zstty_softc),
243     zstty_match, zstty_attach, NULL, NULL);
244 
245 dev_type_open(zsopen);
246 dev_type_close(zsclose);
247 dev_type_read(zsread);
248 dev_type_write(zswrite);
249 dev_type_ioctl(zsioctl);
250 dev_type_stop(zsstop);
251 dev_type_tty(zstty);
252 dev_type_poll(zspoll);
253 
254 const struct cdevsw zstty_cdevsw = {
255 	.d_open = zsopen,
256 	.d_close = zsclose,
257 	.d_read = zsread,
258 	.d_write = zswrite,
259 	.d_ioctl = zsioctl,
260 	.d_stop = zsstop,
261 	.d_tty = zstty,
262 	.d_poll = zspoll,
263 	.d_mmap = nommap,
264 	.d_kqfilter = ttykqfilter,
265 	.d_flag = D_TTY
266 };
267 
268 struct zsops zsops_tty;
269 
270 static void zs_shutdown(struct zstty_softc *);
271 static void	zsstart(struct tty *);
272 static int	zsparam(struct tty *, struct termios *);
273 static void zs_modem(struct zstty_softc *, int);
274 static void tiocm_to_zs(struct zstty_softc *, u_long, int);
275 static int  zs_to_tiocm(struct zstty_softc *);
276 static int    zshwiflow(struct tty *, int);
277 static void  zs_hwiflow(struct zstty_softc *);
278 static void zs_maskintr(struct zstty_softc *);
279 
280 /* Low-level routines. */
281 static void zstty_rxint  (struct zs_chanstate *);
282 static void zstty_stint  (struct zs_chanstate *, int);
283 static void zstty_txint  (struct zs_chanstate *);
284 static void zstty_softint(struct zs_chanstate *);
285 static void zstty_softint1(struct zs_chanstate *);
286 
287 #define	ZSUNIT(x)	(minor(x) & 0x7ffff)
288 #define	ZSDIALOUT(x)	(minor(x) & 0x80000)
289 
290 struct tty *zstty_get_tty_from_dev(device_t);
291 
292 /*
293  * XXX get the (struct tty *) out of a (device_t) we trust to be a
294  * (struct zstty_softc *) - needed by sparc/dev/zs.c, sparc64/dev/zs.c,
295  * sun3/dev/zs.c and sun2/dev/zs.c will probably need it at some point
296  */
297 
298 struct tty *
299 zstty_get_tty_from_dev(device_t dev)
300 {
301 	struct zstty_softc *sc = device_private(dev);
302 
303 	return sc->zst_tty;
304 }
305 
306 /*
307  * zstty_match: how is this zs channel configured?
308  */
309 int
310 zstty_match(device_t parent, cfdata_t cf, void *aux)
311 {
312 	struct zsc_attach_args *args = aux;
313 
314 	/* Exact match is better than wildcard. */
315 	if (cf->zsccf_channel == args->channel)
316 		return 2;
317 
318 	/* This driver accepts wildcard. */
319 	if (cf->zsccf_channel == ZSCCF_CHANNEL_DEFAULT)
320 		return 1;
321 
322 	return 0;
323 }
324 
325 void
326 zstty_attach(device_t parent, device_t self, void *aux)
327 {
328 	struct zstty_softc *zst = device_private(self);
329 	struct zsc_softc *zsc = device_private(parent);
330 	cfdata_t cf = device_cfdata(self);
331 	struct zsc_attach_args *args = aux;
332 	struct zs_chanstate *cs;
333 	struct tty *tp;
334 	int channel, tty_unit;
335 	dev_t dev;
336 	const char *i, *o;
337 	int dtr_on;
338 	int resetbit;
339 
340 	zst->zst_dev = self;
341 
342 	callout_init(&zst->zst_diag_ch, 0);
343 	cn_init_magic(&zstty_cnm_state);
344 
345 	tty_unit = device_unit(self);
346 	channel = args->channel;
347 	cs = zsc->zsc_cs[channel];
348 	cs->cs_private = zst;
349 	cs->cs_ops = &zsops_tty;
350 
351 	zst->zst_cs = cs;
352 	zst->zst_swflags = cf->cf_flags;	/* softcar, etc. */
353 	zst->zst_hwflags = args->hwflags;
354 	dev = makedev(cdevsw_lookup_major(&zstty_cdevsw), tty_unit);
355 
356 	if (zst->zst_swflags)
357 		aprint_normal(" flags 0x%x", zst->zst_swflags);
358 
359 	/*
360 	 * Check whether we serve as a console device.
361 	 * XXX - split console input/output channels aren't
362 	 *	 supported yet on /dev/console
363 	 */
364 	i = o = NULL;
365 	if ((zst->zst_hwflags & ZS_HWFLAG_CONSOLE_INPUT) != 0) {
366 		i = "input";
367 		if ((args->hwflags & ZS_HWFLAG_USE_CONSDEV) != 0) {
368 			args->consdev->cn_dev = dev;
369 			cn_tab->cn_pollc = args->consdev->cn_pollc;
370 			cn_tab->cn_getc = args->consdev->cn_getc;
371 		}
372 		cn_tab->cn_dev = dev;
373 		/* Set console magic to BREAK */
374 		cn_set_magic("\047\001");
375 	}
376 	if ((zst->zst_hwflags & ZS_HWFLAG_CONSOLE_OUTPUT) != 0) {
377 		o = "output";
378 		if ((args->hwflags & ZS_HWFLAG_USE_CONSDEV) != 0) {
379 			cn_tab->cn_putc = args->consdev->cn_putc;
380 		}
381 		cn_tab->cn_dev = dev;
382 	}
383 	if (i != NULL || o != NULL)
384 		aprint_normal(" (console %s)", i ? (o ? "i/o" : i) : o);
385 
386 #ifdef KGDB
387 	if (zs_check_kgdb(cs, dev)) {
388 		/*
389 		 * Allow kgdb to "take over" this port.  Returns true
390 		 * if this serial port is in-use by kgdb.
391 		 */
392 		aprint_normal(" (kgdb)\n");
393 		/*
394 		 * This is the kgdb port (exclusive use)
395 		 * so skip the normal attach code.
396 		 */
397 		return;
398 	}
399 #endif
400 	aprint_normal("\n");
401 
402 	tp = tty_alloc();
403 	tp->t_dev = dev;
404 	tp->t_oproc = zsstart;
405 	tp->t_param = zsparam;
406 	tp->t_hwiflow = zshwiflow;
407 	tty_attach(tp);
408 
409 	zst->zst_tty = tp;
410 	zst->zst_rbuf = malloc(zstty_rbuf_size << 1, M_DEVBUF, M_NOWAIT);
411 	if (zst->zst_rbuf == NULL) {
412 		aprint_error_dev(zst->zst_dev,
413 		    "unable to allocate ring buffer\n");
414 		return;
415 	}
416 	zst->zst_ebuf = zst->zst_rbuf + (zstty_rbuf_size << 1);
417 	/* Disable the high water mark. */
418 	zst->zst_r_hiwat = 0;
419 	zst->zst_r_lowat = 0;
420 	zst->zst_rbget = zst->zst_rbput = zst->zst_rbuf;
421 	zst->zst_rbavail = zstty_rbuf_size;
422 
423 	/* if there are no enable/disable functions, assume the device
424 	   is always enabled */
425 	if (!cs->enable)
426 		cs->enabled = 1;
427 
428 	/*
429 	 * Hardware init
430 	 */
431 	dtr_on = 0;
432 	resetbit = 0;
433 	if (ISSET(zst->zst_hwflags, ZS_HWFLAG_CONSOLE)) {
434 		/* Call zsparam similar to open. */
435 		struct termios t;
436 
437 		/* Wait a while for previous console output to complete */
438 		DELAY(10000);
439 
440 		/* Setup the "new" parameters in t. */
441 		t.c_ispeed = 0;
442 		t.c_ospeed = cs->cs_defspeed;
443 		t.c_cflag = cs->cs_defcflag;
444 
445 		/*
446 		 * Turn on receiver and status interrupts.
447 		 * We defer the actual write of the register to zsparam(),
448 		 * but we must make sure status interrupts are turned on by
449 		 * the time zsparam() reads the initial rr0 state.
450 		 */
451 		SET(cs->cs_preg[1], ZSWR1_RIE | ZSWR1_TIE | ZSWR1_SIE);
452 
453 		/* Make sure zsparam will see changes. */
454 		tp->t_ospeed = 0;
455 		(void) zsparam(tp, &t);
456 
457 		/* Make sure DTR is on now. */
458 		dtr_on = 1;
459 
460 	} else if (!ISSET(zst->zst_hwflags, ZS_HWFLAG_NORESET)) {
461 		/* Not the console; may need reset. */
462 		resetbit = (channel == 0) ? ZSWR9_A_RESET : ZSWR9_B_RESET;
463 	}
464 
465 	mutex_spin_enter(&cs->cs_lock);
466 	if (resetbit)
467 		zs_write_reg(cs, 9, resetbit);
468 	zs_modem(zst, dtr_on);
469 	mutex_spin_exit(&cs->cs_lock);
470 }
471 
472 
473 /*
474  * Return pointer to our tty.
475  */
476 struct tty *
477 zstty(dev_t dev)
478 {
479 	struct zstty_softc *zst;
480 
481 	zst = device_lookup_private(&zstty_cd, ZSUNIT(dev));
482 
483 	return (zst->zst_tty);
484 }
485 
486 
487 void
488 zs_shutdown(struct zstty_softc *zst)
489 {
490 	struct zs_chanstate *cs = zst->zst_cs;
491 	struct tty *tp = zst->zst_tty;
492 
493 	mutex_spin_enter(&cs->cs_lock);
494 
495 	/* If we were asserting flow control, then deassert it. */
496 	SET(zst->zst_rx_flags, RX_IBUF_BLOCKED);
497 	zs_hwiflow(zst);
498 
499 	/* Clear any break condition set with TIOCSBRK. */
500 	zs_break(cs, 0);
501 
502 	/*
503 	 * Hang up if necessary.  Wait a bit, so the other side has time to
504 	 * notice even if we immediately open the port again.
505 	 */
506 	if (ISSET(tp->t_cflag, HUPCL)) {
507 		zs_modem(zst, 0);
508 		mutex_spin_exit(&cs->cs_lock);
509 		/*
510 		 * XXX -    another process is not prevented from opening
511 		 *	    the device during our sleep.
512 		 */
513 		(void) tsleep(cs, TTIPRI, ttclos, hz);
514 		/* Re-check state in case we were opened during our sleep */
515 		if (ISSET(tp->t_state, TS_ISOPEN) || tp->t_wopen != 0)
516 			return;
517 
518 		mutex_spin_enter(&cs->cs_lock);
519 	}
520 
521 	/* Turn off interrupts if not the console. */
522 	if (!ISSET(zst->zst_hwflags, ZS_HWFLAG_CONSOLE)) {
523 		CLR(cs->cs_preg[1], ZSWR1_RIE | ZSWR1_TIE | ZSWR1_SIE);
524 		cs->cs_creg[1] = cs->cs_preg[1];
525 		zs_write_reg(cs, 1, cs->cs_creg[1]);
526 	}
527 
528 	/* Call the power management hook. */
529 	if (cs->disable) {
530 #ifdef DIAGNOSTIC
531 		if (!cs->enabled)
532 			panic("%s: not enabled?", __func__);
533 #endif
534 		(*cs->disable)(zst->zst_cs);
535 	}
536 
537 	mutex_spin_exit(&cs->cs_lock);
538 }
539 
540 /*
541  * Open a zs serial (tty) port.
542  */
543 int
544 zsopen(dev_t dev, int flags, int mode, struct lwp *l)
545 {
546 	struct zstty_softc *zst;
547 	struct zs_chanstate *cs;
548 	struct tty *tp;
549 	int error;
550 
551 	zst = device_lookup_private(&zstty_cd, ZSUNIT(dev));
552 	if (zst == NULL)
553 		return (ENXIO);
554 
555 	tp = zst->zst_tty;
556 	cs = zst->zst_cs;
557 
558 	/* If KGDB took the line, then tp==NULL */
559 	if (tp == NULL)
560 		return (EBUSY);
561 
562 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
563 		return (EBUSY);
564 
565 	mutex_spin_enter(&tty_lock);
566 
567 	/*
568 	 * Do the following iff this is a first open.
569 	 */
570 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
571 		struct termios t;
572 
573 		tp->t_dev = dev;
574 
575 		/* Call the power management hook. */
576 		if (cs->enable) {
577 			if ((*cs->enable)(cs)) {
578 				mutex_spin_exit(&tty_lock);
579 				printf("%s: device enable failed\n",
580 				    device_xname(zst->zst_dev));
581 				return (EIO);
582 			}
583 		}
584 
585 		/*
586 		 * Initialize the termios status to the defaults.  Add in the
587 		 * sticky bits from TIOCSFLAGS.
588 		 */
589 		t.c_ispeed = 0;
590 		t.c_ospeed = cs->cs_defspeed;
591 		t.c_cflag = cs->cs_defcflag;
592 		if (ISSET(zst->zst_swflags, TIOCFLAG_CLOCAL))
593 			SET(t.c_cflag, CLOCAL);
594 		if (ISSET(zst->zst_swflags, TIOCFLAG_CRTSCTS))
595 			SET(t.c_cflag, CRTSCTS);
596 		if (ISSET(zst->zst_swflags, TIOCFLAG_CDTRCTS))
597 			SET(t.c_cflag, CDTRCTS);
598 		if (ISSET(zst->zst_swflags, TIOCFLAG_MDMBUF))
599 			SET(t.c_cflag, MDMBUF);
600 
601 		mutex_spin_enter(&cs->cs_lock);
602 
603 		/*
604 		 * Turn on receiver and status interrupts.
605 		 * We defer the actual write of the register to zsparam(),
606 		 * but we must make sure status interrupts are turned on by
607 		 * the time zsparam() reads the initial rr0 state.
608 		 */
609 		SET(cs->cs_preg[1], ZSWR1_RIE | ZSWR1_TIE | ZSWR1_SIE);
610 
611 		/* Clear PPS capture state on first open. */
612 		mutex_spin_enter(&timecounter_lock);
613 		zst->zst_ppsmask = 0;
614 		memset(&zst->zst_pps_state, 0, sizeof(zst->zst_pps_state));
615 		zst->zst_pps_state.ppscap =
616 		    PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
617 		pps_init(&zst->zst_pps_state);
618 		mutex_spin_exit(&timecounter_lock);
619 
620 		mutex_spin_exit(&cs->cs_lock);
621 
622 		/* Make sure zsparam will see changes. */
623 		tp->t_ospeed = 0;
624 		(void) zsparam(tp, &t);
625 
626 		/*
627 		 * Note: zsparam has done: cflag, ispeed, ospeed
628 		 * so we just need to do: iflag, oflag, lflag, cc
629 		 * For "raw" mode, just leave all zeros.
630 		 */
631 		if (!ISSET(zst->zst_hwflags, ZS_HWFLAG_RAW)) {
632 			tp->t_iflag = TTYDEF_IFLAG;
633 			tp->t_oflag = TTYDEF_OFLAG;
634 			tp->t_lflag = TTYDEF_LFLAG;
635 		} else {
636 			tp->t_iflag = 0;
637 			tp->t_oflag = 0;
638 			tp->t_lflag = 0;
639 		}
640 		ttychars(tp);
641 		ttsetwater(tp);
642 
643 		mutex_spin_enter(&cs->cs_lock);
644 
645 		/*
646 		 * Turn on DTR.  We must always do this, even if carrier is not
647 		 * present, because otherwise we'd have to use TIOCSDTR
648 		 * immediately after setting CLOCAL, which applications do not
649 		 * expect.  We always assert DTR while the device is open
650 		 * unless explicitly requested to deassert it.
651 		 */
652 		zs_modem(zst, 1);
653 
654 		/* Clear the input ring, and unblock. */
655 		zst->zst_rbget = zst->zst_rbput = zst->zst_rbuf;
656 		zst->zst_rbavail = zstty_rbuf_size;
657 		zs_iflush(cs);
658 		CLR(zst->zst_rx_flags, RX_ANY_BLOCK);
659 		zs_hwiflow(zst);
660 
661 		mutex_spin_exit(&cs->cs_lock);
662 	}
663 
664 	mutex_spin_exit(&tty_lock);
665 
666 	error = ttyopen(tp, ZSDIALOUT(dev), ISSET(flags, O_NONBLOCK));
667 	if (error)
668 		goto bad;
669 
670 	error = (*tp->t_linesw->l_open)(dev, tp);
671 	if (error)
672 		goto bad;
673 
674 	return (0);
675 
676 bad:
677 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
678 		/*
679 		 * We failed to open the device, and nobody else had it opened.
680 		 * Clean up the state as appropriate.
681 		 */
682 		zs_shutdown(zst);
683 	}
684 
685 	return (error);
686 }
687 
688 /*
689  * Close a zs serial port.
690  */
691 int
692 zsclose(dev_t dev, int flags, int mode, struct lwp *l)
693 {
694 	struct zstty_softc *zst;
695 	struct tty *tp;
696 
697 	zst = device_lookup_private(&zstty_cd, ZSUNIT(dev));
698 	tp = zst->zst_tty;
699 
700 	/* XXX This is for cons.c. */
701 	if (!ISSET(tp->t_state, TS_ISOPEN))
702 		return 0;
703 
704 	(*tp->t_linesw->l_close)(tp, flags);
705 	ttyclose(tp);
706 
707 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
708 		/*
709 		 * Although we got a last close, the device may still be in
710 		 * use; e.g. if this was the dialout node, and there are still
711 		 * processes waiting for carrier on the non-dialout node.
712 		 */
713 		zs_shutdown(zst);
714 	}
715 
716 	return (0);
717 }
718 
719 /*
720  * Read/write zs serial port.
721  */
722 int
723 zsread(dev_t dev, struct uio *uio, int flags)
724 {
725 	struct zstty_softc *zst;
726 	struct tty *tp;
727 
728 	zst = device_lookup_private(&zstty_cd, ZSUNIT(dev));
729 	tp = zst->zst_tty;
730 
731 	return ((*tp->t_linesw->l_read)(tp, uio, flags));
732 }
733 
734 int
735 zswrite(dev_t dev, struct uio *uio, int flags)
736 {
737 	struct zstty_softc *zst;
738 	struct tty *tp;
739 
740 	zst = device_lookup_private(&zstty_cd, ZSUNIT(dev));
741 	tp = zst->zst_tty;
742 
743 	return ((*tp->t_linesw->l_write)(tp, uio, flags));
744 }
745 
746 int
747 zspoll(dev_t dev, int events, struct lwp *l)
748 {
749 	struct zstty_softc *zst;
750 	struct tty *tp;
751 
752 	zst = device_lookup_private(&zstty_cd, ZSUNIT(dev));
753 	tp = zst->zst_tty;
754 
755 	return ((*tp->t_linesw->l_poll)(tp, events, l));
756 }
757 
758 int
759 zsioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
760 {
761 	struct zstty_softc *zst;
762 	struct zs_chanstate *cs;
763 	struct tty *tp;
764 	int error;
765 
766 	zst = device_lookup_private(&zstty_cd, ZSUNIT(dev));
767 	cs = zst->zst_cs;
768 	tp = zst->zst_tty;
769 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
770 	if (error != EPASSTHROUGH)
771 		return (error);
772 
773 	error = ttioctl(tp, cmd, data, flag, l);
774 	if (error != EPASSTHROUGH)
775 		return (error);
776 
777 #ifdef	ZS_MD_IOCTL
778 	error = ZS_MD_IOCTL(cs, cmd, data);
779 	if (error != EPASSTHROUGH)
780 		return (error);
781 #endif	/* ZS_MD_IOCTL */
782 
783 	error = 0;
784 
785 	mutex_spin_enter(&cs->cs_lock);
786 
787 	switch (cmd) {
788 	case TIOCSBRK:
789 		zs_break(cs, 1);
790 		break;
791 
792 	case TIOCCBRK:
793 		zs_break(cs, 0);
794 		break;
795 
796 	case TIOCGFLAGS:
797 		*(int *)data = zst->zst_swflags;
798 		break;
799 
800 	case TIOCSFLAGS:
801 		error = kauth_authorize_device_tty(l->l_cred,
802 			KAUTH_DEVICE_TTY_PRIVSET, tp);
803 		if (error)
804 			break;
805 		zst->zst_swflags = *(int *)data;
806 		break;
807 
808 	case TIOCSDTR:
809 		zs_modem(zst, 1);
810 		break;
811 
812 	case TIOCCDTR:
813 		zs_modem(zst, 0);
814 		break;
815 
816 	case TIOCMSET:
817 	case TIOCMBIS:
818 	case TIOCMBIC:
819 		tiocm_to_zs(zst, cmd, *(int *)data);
820 		break;
821 
822 	case TIOCMGET:
823 		*(int *)data = zs_to_tiocm(zst);
824 		break;
825 
826 	case PPS_IOC_CREATE:
827 	case PPS_IOC_DESTROY:
828 	case PPS_IOC_GETPARAMS:
829 	case PPS_IOC_SETPARAMS:
830 	case PPS_IOC_GETCAP:
831 	case PPS_IOC_FETCH:
832 #ifdef PPS_SYNC
833 	case PPS_IOC_KCBIND:
834 #endif
835 		mutex_spin_enter(&timecounter_lock);
836 		error = pps_ioctl(cmd, data, &zst->zst_pps_state);
837 		if (zst->zst_pps_state.ppsparam.mode & PPS_CAPTUREBOTH)
838 			zst->zst_ppsmask = ZSRR0_DCD;
839 		else
840 			zst->zst_ppsmask = 0;
841 		mutex_spin_exit(&timecounter_lock);
842 		break;
843 
844 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
845 		if (cs->cs_rr0_pps == 0) {
846 			error = EINVAL;
847 			break;
848 		}
849 		mutex_spin_enter(&timecounter_lock);
850 #ifndef PPS_TRAILING_EDGE
851 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
852 		    &zst->zst_pps_state.ppsinfo.assert_timestamp);
853 #else
854 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
855 		    &zst->zst_pps_state.ppsinfo.clear_timestamp);
856 #endif
857 		mutex_spin_exit(&timecounter_lock);
858 		/*
859 		 * Now update interrupts.
860 		 */
861 		zs_maskintr(zst);
862 		/*
863 		 * If nothing is being transmitted, set up new current values,
864 		 * else mark them as pending.
865 		 */
866 		if (!cs->cs_heldchange) {
867 			if (zst->zst_tx_busy) {
868 				zst->zst_heldtbc = zst->zst_tbc;
869 				zst->zst_tbc = 0;
870 				cs->cs_heldchange = 1;
871 			} else
872 				zs_loadchannelregs(cs);
873 		}
874 
875 		break;
876 
877 	default:
878 		error = EPASSTHROUGH;
879 		break;
880 	}
881 
882 	mutex_spin_exit(&cs->cs_lock);
883 
884 	return (error);
885 }
886 
887 /*
888  * Start or restart transmission.
889  */
890 static void
891 zsstart(struct tty *tp)
892 {
893 	struct zstty_softc *zst;
894 	struct zs_chanstate *cs;
895 	u_char *tba;
896 	int tbc;
897 
898 	zst = device_lookup_private(&zstty_cd, ZSUNIT(tp->t_dev));
899 	cs = zst->zst_cs;
900 
901 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
902 		return;
903 	if (zst->zst_tx_stopped)
904 		return;
905 	if (!ttypull(tp))
906 		return;
907 
908 	/* Grab the first contiguous region of buffer space. */
909 	tba = tp->t_outq.c_cf;
910 	tbc = ndqb(&tp->t_outq, 0);
911 
912 	mutex_spin_enter(&cs->cs_lock);
913 
914 	zst->zst_tba = tba;
915 	zst->zst_tbc = tbc;
916 	SET(tp->t_state, TS_BUSY);
917 	zst->zst_tx_busy = 1;
918 
919 #ifdef ZS_TXDMA
920 	if (zst->zst_tbc > 1) {
921 		zs_dma_setup(cs, zst->zst_tba, zst->zst_tbc);
922 		mutex_spin_exit(&cs->cs_lock);
923 		return;
924 	}
925 #endif
926 
927 	/* Output the first character of the contiguous buffer. */
928 	zs_write_data(cs, *zst->zst_tba);
929 	zst->zst_tbc--;
930 	zst->zst_tba++;
931 
932 	mutex_spin_exit(&cs->cs_lock);
933 }
934 
935 /*
936  * Stop output, e.g., for ^S or output flush.
937  */
938 void
939 zsstop(struct tty *tp, int flag)
940 {
941 	struct zstty_softc *zst;
942 
943 	zst = device_lookup_private(&zstty_cd, ZSUNIT(tp->t_dev));
944 
945 	mutex_spin_enter(&zst->zst_cs->cs_lock);
946 	if (ISSET(tp->t_state, TS_BUSY)) {
947 		/* Stop transmitting at the next chunk. */
948 		zst->zst_tbc = 0;
949 		zst->zst_heldtbc = 0;
950 		if (!ISSET(tp->t_state, TS_TTSTOP))
951 			SET(tp->t_state, TS_FLUSH);
952 	}
953 	mutex_spin_exit(&zst->zst_cs->cs_lock);
954 }
955 
956 /*
957  * Set ZS tty parameters from termios.
958  * XXX - Should just copy the whole termios after
959  * making sure all the changes could be done.
960  */
961 static int
962 zsparam(struct tty *tp, struct termios *t)
963 {
964 	struct zstty_softc *zst;
965 	struct zs_chanstate *cs;
966 	int ospeed;
967 	tcflag_t cflag;
968 	uint8_t tmp3, tmp4, tmp5;
969 	int error;
970 
971 	zst = device_lookup_private(&zstty_cd, ZSUNIT(tp->t_dev));
972 	cs = zst->zst_cs;
973 	ospeed = t->c_ospeed;
974 	cflag = t->c_cflag;
975 
976 	/* Check requested parameters. */
977 	if (ospeed < 0)
978 		return (EINVAL);
979 	if (t->c_ispeed && t->c_ispeed != ospeed)
980 		return (EINVAL);
981 
982 	/*
983 	 * For the console, always force CLOCAL and !HUPCL, so that the port
984 	 * is always active.
985 	 */
986 	if (ISSET(zst->zst_swflags, TIOCFLAG_SOFTCAR) ||
987 	    ISSET(zst->zst_hwflags, ZS_HWFLAG_CONSOLE)) {
988 		SET(cflag, CLOCAL);
989 		CLR(cflag, HUPCL);
990 	}
991 
992 	/*
993 	 * Only whack the UART when params change.
994 	 * Some callers need to clear tp->t_ospeed
995 	 * to make sure initialization gets done.
996 	 */
997 	if (tp->t_ospeed == ospeed &&
998 	    tp->t_cflag == cflag)
999 		return (0);
1000 
1001 	/*
1002 	 * Call MD functions to deal with changed
1003 	 * clock modes or H/W flow control modes.
1004 	 * The BRG divisor is set now. (reg 12,13)
1005 	 */
1006 	error = zs_set_speed(cs, ospeed);
1007 	if (error)
1008 		return (error);
1009 	error = zs_set_modes(cs, cflag);
1010 	if (error)
1011 		return (error);
1012 
1013 	/*
1014 	 * Block interrupts so that state will not
1015 	 * be altered until we are done setting it up.
1016 	 *
1017 	 * Initial values in cs_preg are set before
1018 	 * our attach routine is called.  The master
1019 	 * interrupt enable is handled by zsc.c
1020 	 *
1021 	 */
1022 	mutex_spin_enter(&cs->cs_lock);
1023 
1024 	/*
1025 	 * Recalculate which status ints to enable.
1026 	 */
1027 	zs_maskintr(zst);
1028 
1029 	/* Recompute character size bits. */
1030 	tmp3 = cs->cs_preg[3];
1031 	tmp5 = cs->cs_preg[5];
1032 	CLR(tmp3, ZSWR3_RXSIZE);
1033 	CLR(tmp5, ZSWR5_TXSIZE);
1034 	switch (ISSET(cflag, CSIZE)) {
1035 	case CS5:
1036 		SET(tmp3, ZSWR3_RX_5);
1037 		SET(tmp5, ZSWR5_TX_5);
1038 		break;
1039 	case CS6:
1040 		SET(tmp3, ZSWR3_RX_6);
1041 		SET(tmp5, ZSWR5_TX_6);
1042 		break;
1043 	case CS7:
1044 		SET(tmp3, ZSWR3_RX_7);
1045 		SET(tmp5, ZSWR5_TX_7);
1046 		break;
1047 	case CS8:
1048 		SET(tmp3, ZSWR3_RX_8);
1049 		SET(tmp5, ZSWR5_TX_8);
1050 		break;
1051 	}
1052 	cs->cs_preg[3] = tmp3;
1053 	cs->cs_preg[5] = tmp5;
1054 
1055 	/*
1056 	 * Recompute the stop bits and parity bits.  Note that
1057 	 * zs_set_speed() may have set clock selection bits etc.
1058 	 * in wr4, so those must preserved.
1059 	 */
1060 	tmp4 = cs->cs_preg[4];
1061 	CLR(tmp4, ZSWR4_SBMASK | ZSWR4_PARMASK);
1062 	if (ISSET(cflag, CSTOPB))
1063 		SET(tmp4, ZSWR4_TWOSB);
1064 	else
1065 		SET(tmp4, ZSWR4_ONESB);
1066 	if (!ISSET(cflag, PARODD))
1067 		SET(tmp4, ZSWR4_EVENP);
1068 	if (ISSET(cflag, PARENB))
1069 		SET(tmp4, ZSWR4_PARENB);
1070 	cs->cs_preg[4] = tmp4;
1071 
1072 	/* And copy to tty. */
1073 	tp->t_ispeed = 0;
1074 	tp->t_ospeed = ospeed;
1075 	tp->t_cflag = cflag;
1076 
1077 	/*
1078 	 * If nothing is being transmitted, set up new current values,
1079 	 * else mark them as pending.
1080 	 */
1081 	if (!cs->cs_heldchange) {
1082 		if (zst->zst_tx_busy) {
1083 			zst->zst_heldtbc = zst->zst_tbc;
1084 			zst->zst_tbc = 0;
1085 			cs->cs_heldchange = 1;
1086 		} else
1087 			zs_loadchannelregs(cs);
1088 	}
1089 
1090 	/*
1091 	 * If hardware flow control is disabled, turn off the buffer water
1092 	 * marks and unblock any soft flow control state.  Otherwise, enable
1093 	 * the water marks.
1094 	 */
1095 	if (!ISSET(cflag, CHWFLOW)) {
1096 		zst->zst_r_hiwat = 0;
1097 		zst->zst_r_lowat = 0;
1098 		if (ISSET(zst->zst_rx_flags, RX_TTY_OVERFLOWED)) {
1099 			CLR(zst->zst_rx_flags, RX_TTY_OVERFLOWED);
1100 			zst->zst_rx_ready = 1;
1101 			cs->cs_softreq = 1;
1102 		}
1103 		if (ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
1104 			CLR(zst->zst_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
1105 			zs_hwiflow(zst);
1106 		}
1107 	} else {
1108 		zst->zst_r_hiwat = zstty_rbuf_hiwat;
1109 		zst->zst_r_lowat = zstty_rbuf_lowat;
1110 	}
1111 
1112 	/*
1113 	 * Force a recheck of the hardware carrier and flow control status,
1114 	 * since we may have changed which bits we're looking at.
1115 	 */
1116 	zstty_stint(cs, 1);
1117 
1118 	mutex_spin_exit(&cs->cs_lock);
1119 
1120 	/*
1121 	 * If hardware flow control is disabled, unblock any hard flow control
1122 	 * state.
1123 	 */
1124 	if (!ISSET(cflag, CHWFLOW)) {
1125 		if (zst->zst_tx_stopped) {
1126 			zst->zst_tx_stopped = 0;
1127 			zsstart(tp);
1128 		}
1129 	}
1130 
1131 	zstty_softint1(cs);
1132 
1133 	return (0);
1134 }
1135 
1136 /*
1137  * Compute interrupt enable bits and set in the pending bits. Called both
1138  * in zsparam() and when PPS (pulse per second timing) state changes.
1139  * Must be called at splzs().
1140  */
1141 static void
1142 zs_maskintr(struct zstty_softc *zst)
1143 {
1144 	struct zs_chanstate *cs = zst->zst_cs;
1145 	uint8_t tmp15;
1146 
1147 	cs->cs_rr0_mask = cs->cs_rr0_cts | cs->cs_rr0_dcd;
1148 	if (zst->zst_ppsmask != 0)
1149 		cs->cs_rr0_mask |= cs->cs_rr0_pps;
1150 	tmp15 = cs->cs_preg[15];
1151 	if (ISSET(cs->cs_rr0_mask, ZSRR0_DCD))
1152 		SET(tmp15, ZSWR15_DCD_IE);
1153 	else
1154 		CLR(tmp15, ZSWR15_DCD_IE);
1155 	if (ISSET(cs->cs_rr0_mask, ZSRR0_CTS))
1156 		SET(tmp15, ZSWR15_CTS_IE);
1157 	else
1158 		CLR(tmp15, ZSWR15_CTS_IE);
1159 	cs->cs_preg[15] = tmp15;
1160 }
1161 
1162 
1163 /*
1164  * Raise or lower modem control (DTR/RTS) signals.  If a character is
1165  * in transmission, the change is deferred.
1166  * Called at splzs() and with the channel lock held.
1167  */
1168 static void
1169 zs_modem(struct zstty_softc *zst, int onoff)
1170 {
1171 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
1172 
1173 	if (cs->cs_wr5_dtr == 0)
1174 		return;
1175 
1176 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
1177 
1178 	if (onoff)
1179 		SET(ccs->cs_preg[5], cs->cs_wr5_dtr);
1180 	else
1181 		CLR(ccs->cs_preg[5], cs->cs_wr5_dtr);
1182 
1183 	if (!cs->cs_heldchange) {
1184 		if (zst->zst_tx_busy) {
1185 			zst->zst_heldtbc = zst->zst_tbc;
1186 			zst->zst_tbc = 0;
1187 			cs->cs_heldchange = 1;
1188 		} else
1189 			zs_loadchannelregs(cs);
1190 	}
1191 }
1192 
1193 /*
1194  * Set modem bits.
1195  * Called at splzs() and with the channel lock held.
1196  */
1197 static void
1198 tiocm_to_zs(struct zstty_softc *zst, u_long how, int ttybits)
1199 {
1200 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
1201 	uint8_t zsbits;
1202 
1203 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
1204 
1205 	zsbits = 0;
1206 	if (ISSET(ttybits, TIOCM_DTR))
1207 		SET(zsbits, ZSWR5_DTR);
1208 	if (ISSET(ttybits, TIOCM_RTS))
1209 		SET(zsbits, ZSWR5_RTS);
1210 
1211 	switch (how) {
1212 	case TIOCMBIC:
1213 		CLR(ccs->cs_preg[5], zsbits);
1214 		break;
1215 
1216 	case TIOCMBIS:
1217 		SET(ccs->cs_preg[5], zsbits);
1218 		break;
1219 
1220 	case TIOCMSET:
1221 		CLR(ccs->cs_preg[5], ZSWR5_RTS | ZSWR5_DTR);
1222 		SET(ccs->cs_preg[5], zsbits);
1223 		break;
1224 	}
1225 
1226 	if (!cs->cs_heldchange) {
1227 		if (zst->zst_tx_busy) {
1228 			zst->zst_heldtbc = zst->zst_tbc;
1229 			zst->zst_tbc = 0;
1230 			cs->cs_heldchange = 1;
1231 		} else
1232 			zs_loadchannelregs(cs);
1233 	}
1234 }
1235 
1236 /*
1237  * Get modem bits.
1238  * Called at splzs() and with the channel lock held.
1239  */
1240 static int
1241 zs_to_tiocm(struct zstty_softc *zst)
1242 {
1243 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
1244 	uint8_t zsbits;
1245 	int ttybits = 0;
1246 
1247 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
1248 
1249 	zsbits = ccs->cs_preg[5];
1250 	if (ISSET(zsbits, ZSWR5_DTR))
1251 		SET(ttybits, TIOCM_DTR);
1252 	if (ISSET(zsbits, ZSWR5_RTS))
1253 		SET(ttybits, TIOCM_RTS);
1254 
1255 	zsbits = cs->cs_rr0;
1256 	if (ISSET(zsbits, ZSRR0_DCD))
1257 		SET(ttybits, TIOCM_CD);
1258 	if (ISSET(zsbits, ZSRR0_CTS))
1259 		SET(ttybits, TIOCM_CTS);
1260 
1261 	return (ttybits);
1262 }
1263 
1264 /*
1265  * Try to block or unblock input using hardware flow-control.
1266  * This is called by kern/tty.c if MDMBUF|CRTSCTS is set, and
1267  * if this function returns non-zero, the TS_TBLOCK flag will
1268  * be set or cleared according to the "block" arg passed.
1269  */
1270 int
1271 zshwiflow(struct tty *tp, int block)
1272 {
1273 	struct zstty_softc *zst;
1274 	struct zs_chanstate *cs;
1275 
1276 	zst = device_lookup_private(&zstty_cd, ZSUNIT(tp->t_dev));
1277 	cs = zst->zst_cs;
1278 
1279 	if (cs->cs_wr5_rts == 0)
1280 		return (0);
1281 
1282 	mutex_spin_enter(&cs->cs_lock);
1283 	if (block) {
1284 		if (!ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED)) {
1285 			SET(zst->zst_rx_flags, RX_TTY_BLOCKED);
1286 			zs_hwiflow(zst);
1287 		}
1288 	} else {
1289 		if (ISSET(zst->zst_rx_flags, RX_TTY_OVERFLOWED)) {
1290 			CLR(zst->zst_rx_flags, RX_TTY_OVERFLOWED);
1291 			zst->zst_rx_ready = 1;
1292 			cs->cs_softreq = 1;
1293 		}
1294 		if (ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED)) {
1295 			CLR(zst->zst_rx_flags, RX_TTY_BLOCKED);
1296 			zs_hwiflow(zst);
1297 		}
1298 	}
1299 	mutex_spin_exit(&cs->cs_lock);
1300 	return (1);
1301 }
1302 
1303 /*
1304  * Internal version of zshwiflow
1305  * Called at splzs() and with the channel lock held.
1306  */
1307 static void
1308 zs_hwiflow(struct zstty_softc *zst)
1309 {
1310 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
1311 
1312 	if (cs->cs_wr5_rts == 0)
1313 		return;
1314 
1315 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
1316 
1317 	if (ISSET(zst->zst_rx_flags, RX_ANY_BLOCK)) {
1318 		CLR(ccs->cs_preg[5], cs->cs_wr5_rts);
1319 		CLR(ccs->cs_creg[5], cs->cs_wr5_rts);
1320 	} else {
1321 		SET(ccs->cs_preg[5], cs->cs_wr5_rts);
1322 		SET(ccs->cs_creg[5], cs->cs_wr5_rts);
1323 	}
1324 	zs_write_reg(ccs, 5, ccs->cs_creg[5]);
1325 }
1326 
1327 
1328 /****************************************************************
1329  * Interface to the lower layer (zscc)
1330  ****************************************************************/
1331 
1332 #define	integrate	static inline
1333 integrate void zstty_rxsoft(struct zstty_softc *, struct tty *);
1334 integrate void zstty_txsoft(struct zstty_softc *, struct tty *);
1335 integrate void zstty_stsoft(struct zstty_softc *, struct tty *);
1336 static void zstty_diag(void *);
1337 
1338 /*
1339  * Receiver Ready interrupt.
1340  * Called at splzs() and with the channel lock held.
1341  */
1342 static void
1343 zstty_rxint(struct zs_chanstate *cs)
1344 {
1345 	struct zstty_softc *zst = cs->cs_private;
1346 	uint8_t *put, *end;
1347 	u_int cc;
1348 	uint8_t rr0, rr1, c;
1349 
1350 	end = zst->zst_ebuf;
1351 	put = zst->zst_rbput;
1352 	cc = zst->zst_rbavail;
1353 
1354 	while (cc > 0) {
1355 		/*
1356 		 * First read the status, because reading the received char
1357 		 * destroys the status of this char.
1358 		 */
1359 		rr1 = zs_read_reg(cs, 1);
1360 		c = zs_read_data(cs);
1361 
1362 		if (ISSET(rr1, ZSRR1_FE | ZSRR1_DO | ZSRR1_PE)) {
1363 			/* Clear the receive error. */
1364 			zs_write_csr(cs, ZSWR0_RESET_ERRORS);
1365 		}
1366 
1367 		cn_check_magic(zst->zst_tty->t_dev, c, zstty_cnm_state);
1368 		put[0] = c;
1369 		put[1] = rr1;
1370 		put += 2;
1371 		if (put >= end)
1372 			put = zst->zst_rbuf;
1373 		cc--;
1374 
1375 		rr0 = zs_read_csr(cs);
1376 		if (!ISSET(rr0, ZSRR0_RX_READY))
1377 			break;
1378 	}
1379 
1380 	/*
1381 	 * Current string of incoming characters ended because
1382 	 * no more data was available or we ran out of space.
1383 	 * Schedule a receive event if any data was received.
1384 	 * If we're out of space, turn off receive interrupts.
1385 	 */
1386 	zst->zst_rbput = put;
1387 	zst->zst_rbavail = cc;
1388 	if (!ISSET(zst->zst_rx_flags, RX_TTY_OVERFLOWED)) {
1389 		zst->zst_rx_ready = 1;
1390 		cs->cs_softreq = 1;
1391 	}
1392 
1393 	/*
1394 	 * See if we are in danger of overflowing a buffer. If
1395 	 * so, use hardware flow control to ease the pressure.
1396 	 */
1397 	if (!ISSET(zst->zst_rx_flags, RX_IBUF_BLOCKED) &&
1398 	    cc < zst->zst_r_hiwat) {
1399 		SET(zst->zst_rx_flags, RX_IBUF_BLOCKED);
1400 		zs_hwiflow(zst);
1401 	}
1402 
1403 	/*
1404 	 * If we're out of space, disable receive interrupts
1405 	 * until the queue has drained a bit.
1406 	 */
1407 	if (!cc) {
1408 		SET(zst->zst_rx_flags, RX_IBUF_OVERFLOWED);
1409 		CLR(cs->cs_preg[1], ZSWR1_RIE);
1410 		cs->cs_creg[1] = cs->cs_preg[1];
1411 		zs_write_reg(cs, 1, cs->cs_creg[1]);
1412 	}
1413 
1414 #if 0
1415 	printf("%xH%04d\n", zst->zst_rx_flags, zst->zst_rbavail);
1416 #endif
1417 }
1418 
1419 /*
1420  * Transmitter Ready interrupt.
1421  * Called at splzs() and with the channel lock held.
1422  */
1423 static void
1424 zstty_txint(struct zs_chanstate *cs)
1425 {
1426 	struct zstty_softc *zst = cs->cs_private;
1427 
1428 	zs_write_csr(cs, ZSWR0_RESET_TXINT);
1429 
1430 	/*
1431 	 * If we've delayed a parameter change, do it now, and restart
1432 	 * output.
1433 	 */
1434 	if (cs->cs_heldchange) {
1435 		zs_loadchannelregs(cs);
1436 		cs->cs_heldchange = 0;
1437 		zst->zst_tbc = zst->zst_heldtbc;
1438 		zst->zst_heldtbc = 0;
1439 	}
1440 
1441 	/* Output the next character in the buffer, if any. */
1442 	if (zst->zst_tbc > 0) {
1443 		zs_write_data(cs, *zst->zst_tba);
1444 		zst->zst_tbc--;
1445 		zst->zst_tba++;
1446 	} else {
1447 		if (zst->zst_tx_busy) {
1448 			zst->zst_tx_busy = 0;
1449 			zst->zst_tx_done = 1;
1450 			cs->cs_softreq = 1;
1451 		}
1452 	}
1453 }
1454 
1455 /*
1456  * Status Change interrupt.
1457  * Called at splzs() and with the channel lock held.
1458  */
1459 static void
1460 zstty_stint(struct zs_chanstate *cs, int force)
1461 {
1462 	struct zstty_softc *zst = cs->cs_private;
1463 	uint8_t rr0, delta;
1464 
1465 	rr0 = zs_read_csr(cs);
1466 	zs_write_csr(cs, ZSWR0_RESET_STATUS);
1467 
1468 	/*
1469 	 * Check here for console break, so that we can abort
1470 	 * even when interrupts are locking up the machine.
1471 	 */
1472 	if (ISSET(rr0, ZSRR0_BREAK))
1473 		cn_check_magic(zst->zst_tty->t_dev, CNC_BREAK, zstty_cnm_state);
1474 
1475 	if (!force)
1476 		delta = rr0 ^ cs->cs_rr0;
1477 	else
1478 		delta = cs->cs_rr0_mask;
1479 	cs->cs_rr0 = rr0;
1480 
1481 	if (ISSET(delta, cs->cs_rr0_mask)) {
1482 		SET(cs->cs_rr0_delta, delta);
1483 
1484 		/*
1485 		 * Pulse-per-second clock signal on edge of DCD?
1486 		 */
1487 		if (ISSET(delta, zst->zst_ppsmask)) {
1488 			if (zst->zst_pps_state.ppsparam.mode &
1489 			    PPS_CAPTUREBOTH) {
1490 				mutex_spin_enter(&timecounter_lock);
1491 				pps_capture(&zst->zst_pps_state);
1492 				pps_event(&zst->zst_pps_state,
1493 				    (ISSET(cs->cs_rr0, zst->zst_ppsmask))
1494 				    ? PPS_CAPTUREASSERT
1495 				    : PPS_CAPTURECLEAR);
1496 				mutex_spin_exit(&timecounter_lock);
1497 			}
1498 		}
1499 
1500 		/*
1501 		 * Stop output immediately if we lose the output
1502 		 * flow control signal or carrier detect.
1503 		 */
1504 		if (ISSET(~rr0, cs->cs_rr0_mask)) {
1505 			zst->zst_tbc = 0;
1506 			zst->zst_heldtbc = 0;
1507 		}
1508 
1509 		zst->zst_st_check = 1;
1510 		cs->cs_softreq = 1;
1511 	}
1512 }
1513 
1514 void
1515 zstty_diag(void *arg)
1516 {
1517 	struct zstty_softc *zst = arg;
1518 	int overflows, floods;
1519 
1520 	mutex_spin_enter(&zst->zst_cs->cs_lock);
1521 	overflows = zst->zst_overflows;
1522 	zst->zst_overflows = 0;
1523 	floods = zst->zst_floods;
1524 	zst->zst_floods = 0;
1525 	zst->zst_errors = 0;
1526 	mutex_spin_exit(&zst->zst_cs->cs_lock);
1527 
1528 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
1529 	    device_xname(zst->zst_dev),
1530 	    overflows, overflows == 1 ? "" : "s",
1531 	    floods, floods == 1 ? "" : "s");
1532 }
1533 
1534 integrate void
1535 zstty_rxsoft(struct zstty_softc *zst, struct tty *tp)
1536 {
1537 	struct zs_chanstate *cs = zst->zst_cs;
1538 	int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
1539 	uint8_t *get, *end;
1540 	u_int cc, scc;
1541 	uint8_t rr1;
1542 	int code;
1543 
1544 	end = zst->zst_ebuf;
1545 	get = zst->zst_rbget;
1546 	scc = cc = zstty_rbuf_size - zst->zst_rbavail;
1547 
1548 	if (cc == zstty_rbuf_size) {
1549 		zst->zst_floods++;
1550 		if (zst->zst_errors++ == 0)
1551 			callout_reset(&zst->zst_diag_ch, 60 * hz,
1552 			    zstty_diag, zst);
1553 	}
1554 
1555 	/* If not yet open, drop the entire buffer content here */
1556 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
1557 		get += cc << 1;
1558 		if (get >= end)
1559 			get -= zstty_rbuf_size << 1;
1560 		cc = 0;
1561 	}
1562 	while (cc) {
1563 		code = get[0];
1564 		rr1 = get[1];
1565 		if (ISSET(rr1, ZSRR1_DO | ZSRR1_FE | ZSRR1_PE)) {
1566 			if (ISSET(rr1, ZSRR1_DO)) {
1567 				zst->zst_overflows++;
1568 				if (zst->zst_errors++ == 0)
1569 					callout_reset(&zst->zst_diag_ch,
1570 					    60 * hz, zstty_diag, zst);
1571 			}
1572 			if (ISSET(rr1, ZSRR1_FE))
1573 				SET(code, TTY_FE);
1574 			if (ISSET(rr1, ZSRR1_PE))
1575 				SET(code, TTY_PE);
1576 		}
1577 		if ((*rint)(code, tp) == -1) {
1578 			/*
1579 			 * The line discipline's buffer is out of space.
1580 			 */
1581 			if (!ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED)) {
1582 				/*
1583 				 * We're either not using flow control, or the
1584 				 * line discipline didn't tell us to block for
1585 				 * some reason.  Either way, we have no way to
1586 				 * know when there's more space available, so
1587 				 * just drop the rest of the data.
1588 				 */
1589 				get += cc << 1;
1590 				if (get >= end)
1591 					get -= zstty_rbuf_size << 1;
1592 				cc = 0;
1593 			} else {
1594 				/*
1595 				 * Don't schedule any more receive processing
1596 				 * until the line discipline tells us there's
1597 				 * space available (through comhwiflow()).
1598 				 * Leave the rest of the data in the input
1599 				 * buffer.
1600 				 */
1601 				SET(zst->zst_rx_flags, RX_TTY_OVERFLOWED);
1602 			}
1603 			break;
1604 		}
1605 		get += 2;
1606 		if (get >= end)
1607 			get = zst->zst_rbuf;
1608 		cc--;
1609 	}
1610 
1611 	if (cc != scc) {
1612 		zst->zst_rbget = get;
1613 		mutex_spin_enter(&cs->cs_lock);
1614 		cc = zst->zst_rbavail += scc - cc;
1615 		/* Buffers should be ok again, release possible block. */
1616 		if (cc >= zst->zst_r_lowat) {
1617 			if (ISSET(zst->zst_rx_flags, RX_IBUF_OVERFLOWED)) {
1618 				CLR(zst->zst_rx_flags, RX_IBUF_OVERFLOWED);
1619 				SET(cs->cs_preg[1], ZSWR1_RIE);
1620 				cs->cs_creg[1] = cs->cs_preg[1];
1621 				zs_write_reg(cs, 1, cs->cs_creg[1]);
1622 			}
1623 			if (ISSET(zst->zst_rx_flags, RX_IBUF_BLOCKED)) {
1624 				CLR(zst->zst_rx_flags, RX_IBUF_BLOCKED);
1625 				zs_hwiflow(zst);
1626 			}
1627 		}
1628 		mutex_spin_exit(&cs->cs_lock);
1629 	}
1630 
1631 #if 0
1632 	printf("%xS%04d\n", zst->zst_rx_flags, zst->zst_rbavail);
1633 #endif
1634 }
1635 
1636 integrate void
1637 zstty_txsoft(struct zstty_softc *zst, struct tty *tp)
1638 {
1639 	struct zs_chanstate *cs = zst->zst_cs;
1640 
1641 	mutex_spin_enter(&cs->cs_lock);
1642 	CLR(tp->t_state, TS_BUSY);
1643 	if (ISSET(tp->t_state, TS_FLUSH))
1644 		CLR(tp->t_state, TS_FLUSH);
1645 	else
1646 		ndflush(&tp->t_outq, (int)(zst->zst_tba - tp->t_outq.c_cf));
1647 	mutex_spin_exit(&cs->cs_lock);
1648 	(*tp->t_linesw->l_start)(tp);
1649 }
1650 
1651 integrate void
1652 zstty_stsoft(struct zstty_softc *zst, struct tty *tp)
1653 {
1654 	struct zs_chanstate *cs = zst->zst_cs;
1655 	uint8_t rr0, delta;
1656 
1657 	mutex_spin_enter(&cs->cs_lock);
1658 	rr0 = cs->cs_rr0;
1659 	delta = cs->cs_rr0_delta;
1660 	cs->cs_rr0_delta = 0;
1661 	mutex_spin_exit(&cs->cs_lock);
1662 
1663 	if (ISSET(delta, cs->cs_rr0_dcd)) {
1664 		/*
1665 		 * Inform the tty layer that carrier detect changed.
1666 		 */
1667 		mutex_spin_exit(&tty_lock);
1668 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(rr0, ZSRR0_DCD));
1669 		mutex_spin_enter(&tty_lock);
1670 	}
1671 
1672 	if (ISSET(delta, cs->cs_rr0_cts)) {
1673 		/* Block or unblock output according to flow control. */
1674 		if (ISSET(rr0, cs->cs_rr0_cts)) {
1675 			zst->zst_tx_stopped = 0;
1676 			(*tp->t_linesw->l_start)(tp);
1677 		} else {
1678 			zst->zst_tx_stopped = 1;
1679 		}
1680 	}
1681 }
1682 
1683 /*
1684  * Software interrupt.  Called at zssoft
1685  *
1686  * The main job to be done here is to empty the input ring
1687  * by passing its contents up to the tty layer.  The ring is
1688  * always emptied during this operation, therefore the ring
1689  * must not be larger than the space after "high water" in
1690  * the tty layer, or the tty layer might drop our input.
1691  *
1692  * Note: an "input blockage" condition is assumed to exist if
1693  * EITHER the TS_TBLOCK flag or zst_rx_blocked flag is set.
1694  */
1695 static void
1696 zstty_softint(struct zs_chanstate *cs)
1697 {
1698 
1699 	zstty_softint1(cs);
1700 }
1701 
1702 static void
1703 zstty_softint1(struct zs_chanstate *cs)
1704 {
1705 	struct zstty_softc *zst = cs->cs_private;
1706 	struct tty *tp = zst->zst_tty;
1707 
1708 
1709 	if (zst->zst_rx_ready) {
1710 		zst->zst_rx_ready = 0;
1711 		zstty_rxsoft(zst, tp);
1712 	}
1713 
1714 	if (zst->zst_st_check) {
1715 		zst->zst_st_check = 0;
1716 		zstty_stsoft(zst, tp);
1717 	}
1718 
1719 	if (zst->zst_tx_done) {
1720 		zst->zst_tx_done = 0;
1721 		zstty_txsoft(zst, tp);
1722 	}
1723 }
1724 
1725 struct zsops zsops_tty = {
1726 	zstty_rxint,	/* receive char available */
1727 	zstty_stint,	/* external/status */
1728 	zstty_txint,	/* xmit buffer empty */
1729 	zstty_softint,	/* process software interrupt */
1730 };
1731 
1732 #ifdef ZS_TXDMA
1733 void
1734 zstty_txdma_int(void *arg)
1735 {
1736 	struct zs_chanstate *cs = arg;
1737 	struct zstty_softc *zst = cs->cs_private;
1738 
1739 	zst->zst_tba += zst->zst_tbc;
1740 	zst->zst_tbc = 0;
1741 
1742 	if (zst->zst_tx_busy) {
1743 		zst->zst_tx_busy = 0;
1744 		zst->zst_tx_done = 1;
1745 		cs->cs_softreq = 1;
1746 	}
1747 }
1748 #endif
1749