xref: /netbsd-src/sys/arch/atari/dev/zs.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /*	$NetBSD: zs.c,v 1.54 2007/11/19 18:51:39 ad Exp $	*/
2 
3 /*
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This software was developed by the Computer Systems Engineering group
8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9  * contributed to Berkeley.
10  *
11  *
12  * All advertising materials mentioning features or use of this software
13  * must display the following acknowledgement:
14  *	This product includes software developed by the University of
15  *	California, Lawrence Berkeley Laboratory.
16  *
17  * Redistribution and use in source and binary forms, with or without
18  * modification, are permitted provided that the following conditions
19  * are met:
20  * 1. Redistributions of source code must retain the above copyright
21  *    notice, this list of conditions and the following disclaimer.
22  * 2. Redistributions in binary form must reproduce the above copyright
23  *    notice, this list of conditions and the following disclaimer in the
24  *    documentation and/or other materials provided with the distribution.
25  * 3. Neither the name of the University nor the names of its contributors
26  *    may be used to endorse or promote products derived from this software
27  *    without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  *
41  *	@(#)zs.c	8.1 (Berkeley) 7/19/93
42  */
43 
44 /*-
45  * Copyright (c) 1995 The NetBSD Foundation, Inc. (Atari modifications)
46  * All rights reserved.
47  *
48  * This code is derived from software contributed to The NetBSD Foundation
49  * by Leo Weppelman.
50  *
51  * Redistribution and use in source and binary forms, with or without
52  * modification, are permitted provided that the following conditions
53  * are met:
54  * 1. Redistributions of source code must retain the above copyright
55  *    notice, this list of conditions and the following disclaimer.
56  * 2. Redistributions in binary form must reproduce the above copyright
57  *    notice, this list of conditions and the following disclaimer in the
58  *    documentation and/or other materials provided with the distribution.
59  * 3. Neither the name of The NetBSD Foundation nor the names of its
60  *    contributors may be used to endorse or promote products derived
61  *    from this software without specific prior written permission.
62  *
63  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
64  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
65  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
66  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
67  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
68  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
69  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
70  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
71  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
72  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
73  * POSSIBILITY OF SUCH DAMAGE.
74  */
75 
76 /*
77  * Zilog Z8530 (ZSCC) driver.
78  *
79  * Runs two tty ports (modem2 and serial2) on zs0.
80  *
81  * This driver knows far too much about chip to usage mappings.
82  */
83 
84 #include <sys/cdefs.h>
85 __KERNEL_RCSID(0, "$NetBSD: zs.c,v 1.54 2007/11/19 18:51:39 ad Exp $");
86 
87 #include <sys/param.h>
88 #include <sys/systm.h>
89 #include <sys/proc.h>
90 #include <sys/device.h>
91 #include <sys/conf.h>
92 #include <sys/file.h>
93 #include <sys/ioctl.h>
94 #include <sys/malloc.h>
95 #include <sys/tty.h>
96 #include <sys/time.h>
97 #include <sys/kernel.h>
98 #include <sys/syslog.h>
99 #include <sys/kauth.h>
100 
101 #include <machine/cpu.h>
102 #include <machine/iomap.h>
103 #include <machine/scu.h>
104 #include <machine/mfp.h>
105 #include <atari/dev/ym2149reg.h>
106 
107 #include <dev/ic/z8530reg.h>
108 #include <atari/dev/zsvar.h>
109 #include "zs.h"
110 #if NZS > 1
111 #error "This driver supports only 1 85C30!"
112 #endif
113 
114 #if NZS > 0
115 
116 #define PCLK	(8053976)	/* PCLK pin input clock rate */
117 #define PCLK_HD	(9600 * 1536)	/* PCLK on Hades pin input clock rate */
118 
119 #define splzs	spl5
120 
121 /*
122  * Software state per found chip.
123  */
124 struct zs_softc {
125     struct	device		zi_dev;    /* base device		  */
126     volatile struct zsdevice	*zi_zs;    /* chip registers		  */
127     struct	zs_chanstate	zi_cs[2];  /* chan A and B software state */
128 };
129 
130 static u_char	cb_scheduled = 0;	/* Already asked for callback? */
131 /*
132  * Define the registers for a closed port
133  */
134 static u_char zs_init_regs[16] = {
135 /*  0 */	0,
136 /*  1 */	0,
137 /*  2 */	0x60,
138 /*  3 */	0,
139 /*  4 */	0,
140 /*  5 */	0,
141 /*  6 */	0,
142 /*  7 */	0,
143 /*  8 */	0,
144 /*  9 */	ZSWR9_MASTER_IE | ZSWR9_VECTOR_INCL_STAT,
145 /* 10 */	ZSWR10_NRZ,
146 /* 11 */	ZSWR11_TXCLK_BAUD | ZSWR11_RXCLK_BAUD,
147 /* 12 */	0,
148 /* 13 */	0,
149 /* 14 */	ZSWR14_BAUD_FROM_PCLK | ZSWR14_BAUD_ENA,
150 /* 15 */	0
151 };
152 
153 /*
154  * Define the machine dependant clock frequencies
155  * If BRgen feeds sender/receiver we always use a
156  * divisor 16, therefor the division by 16 can as
157  * well be done here.
158  */
159 static u_long zs_freqs_tt[] = {
160 	/*
161 	 * Atari TT, RTxCB is generated by TT-MFP timer C,
162 	 * which is set to 307.2 kHz during initialisation
163 	 * and never changed afterwards.
164 	 */
165 	PCLK/16,	/* BRgen, PCLK,  divisor 16	*/
166 	 229500,	/* BRgen, RTxCA, divisor 16	*/
167 	3672000,	/* RTxCA, from PCLK4		*/
168 	      0,	/* TRxCA, external		*/
169 
170 	PCLK/16,	/* BRgen, PCLK,  divisor 16	*/
171 	  19200,	/* BRgen, RTxCB, divisor 16	*/
172 	 307200,	/* RTxCB, from TT-MFP TCO	*/
173 	2457600		/* TRxCB, from BCLK		*/
174 };
175 
176 static u_long zs_freqs_falcon[] = {
177 	/*
178 	 * Atari Falcon, XXX no specs available, this might be wrong
179 	 */
180 	PCLK/16,	/* BRgen, PCLK,  divisor 16	*/
181 	 229500,	/* BRgen, RTxCA, divisor 16	*/
182 	3672000,	/* RTxCA, ???			*/
183 	      0,	/* TRxCA, external		*/
184 
185 	PCLK/16,	/* BRgen, PCLK,  divisor 16	*/
186 	 229500,	/* BRgen, RTxCB, divisor 16	*/
187 	3672000,	/* RTxCB, ???			*/
188 	2457600		/* TRxCB, ???			*/
189 };
190 
191 static u_long zs_freqs_hades[] = {
192 	/*
193 	 * XXX: Channel-A unchecked!!!!!
194 	 */
195      PCLK_HD/16,	/* BRgen, PCLK,  divisor 16	*/
196 	 229500,	/* BRgen, RTxCA, divisor 16	*/
197 	3672000,	/* RTxCA, from PCLK4		*/
198 	      0,	/* TRxCA, external		*/
199 
200      PCLK_HD/16,	/* BRgen, PCLK,  divisor 16	*/
201 	 235550,	/* BRgen, RTxCB, divisor 16	*/
202 	3768800,	/* RTxCB, 3.7688MHz		*/
203 	3768800		/* TRxCB, 3.7688MHz		*/
204 };
205 
206 static u_long zs_freqs_generic[] = {
207 	/*
208 	 * other machines, assume only PCLK is available
209 	 */
210 	PCLK/16,	/* BRgen, PCLK,  divisor 16	*/
211 	      0,	/* BRgen, RTxCA, divisor 16	*/
212 	      0,	/* RTxCA, unknown		*/
213 	      0,	/* TRxCA, unknown		*/
214 
215 	PCLK/16,	/* BRgen, PCLK,  divisor 16	*/
216 	      0,	/* BRgen, RTxCB, divisor 16	*/
217 	      0,	/* RTxCB, unknown		*/
218 	      0		/* TRxCB, unknown		*/
219 };
220 static u_long *zs_frequencies;
221 
222 /* Definition of the driver for autoconfig. */
223 static int	zsmatch __P((struct device *, struct cfdata *, void *));
224 static void	zsattach __P((struct device *, struct device *, void *));
225 
226 CFATTACH_DECL(zs, sizeof(struct zs_softc),
227     zsmatch, zsattach, NULL, NULL);
228 
229 extern struct cfdriver zs_cd;
230 
231 /* {b,c}devsw[] function prototypes */
232 dev_type_open(zsopen);
233 dev_type_close(zsclose);
234 dev_type_read(zsread);
235 dev_type_write(zswrite);
236 dev_type_ioctl(zsioctl);
237 dev_type_stop(zsstop);
238 dev_type_tty(zstty);
239 dev_type_poll(zspoll);
240 
241 const struct cdevsw zs_cdevsw = {
242 	zsopen, zsclose, zsread, zswrite, zsioctl,
243 	zsstop, zstty, zspoll, nommap, ttykqfilter, D_TTY
244 };
245 
246 /* Interrupt handlers. */
247 int		zshard __P((long));
248 static int	zssoft __P((long));
249 static int	zsrint __P((struct zs_chanstate *, volatile struct zschan *));
250 static int	zsxint __P((struct zs_chanstate *, volatile struct zschan *));
251 static int	zssint __P((struct zs_chanstate *, volatile struct zschan *));
252 
253 static struct zs_chanstate *zslist;
254 
255 /* Routines called from other code. */
256 static void	zsstart __P((struct tty *));
257 
258 /* Routines purely local to this driver. */
259 static void	zsoverrun __P((int, long *, const char *));
260 static int	zsparam __P((struct tty *, struct termios *));
261 static int	zsbaudrate __P((int, int, int *, int *, int *, int *));
262 static int	zs_modem __P((struct zs_chanstate *, int, int));
263 static void	zs_loadchannelregs __P((volatile struct zschan *, u_char *));
264 static void	zs_shutdown __P((struct zs_chanstate *));
265 
266 static int zsshortcuts;	/* number of "shortcut" software interrupts */
267 
268 static int
269 zsmatch(pdp, cfp, auxp)
270 struct device	*pdp;
271 struct cfdata	*cfp;
272 void		*auxp;
273 {
274 	static int	zs_matched = 0;
275 
276 	if(strcmp("zs", auxp) || zs_matched)
277 		return(0);
278 	zs_matched = 1;
279 	return(1);
280 }
281 
282 /*
283  * Attach a found zs.
284  */
285 static void
286 zsattach(parent, dev, aux)
287 struct device	*parent;
288 struct device	*dev;
289 void		*aux;
290 {
291 	register struct zs_softc		*zi;
292 	register struct zs_chanstate		*cs;
293 	register volatile struct zsdevice	*addr;
294 		 char				tmp;
295 
296 	addr      = (struct zsdevice *)AD_SCC;
297 	zi        = (struct zs_softc *)dev;
298 	zi->zi_zs = addr;
299 	cs        = zi->zi_cs;
300 
301 	/*
302 	 * Get the command register into a known state.
303 	 */
304 	tmp = addr->zs_chan[ZS_CHAN_A].zc_csr;
305 	tmp = addr->zs_chan[ZS_CHAN_A].zc_csr;
306 	tmp = addr->zs_chan[ZS_CHAN_B].zc_csr;
307 	tmp = addr->zs_chan[ZS_CHAN_B].zc_csr;
308 
309 	/*
310 	 * Do a hardware reset.
311 	 */
312 	ZS_WRITE(&addr->zs_chan[ZS_CHAN_A], 9, ZSWR9_HARD_RESET);
313 	delay(50000);	/*enough ? */
314 	ZS_WRITE(&addr->zs_chan[ZS_CHAN_A], 9, 0);
315 
316 	/*
317 	 * Initialize both channels
318 	 */
319 	zs_loadchannelregs(&addr->zs_chan[ZS_CHAN_A], zs_init_regs);
320 	zs_loadchannelregs(&addr->zs_chan[ZS_CHAN_B], zs_init_regs);
321 
322 	if(machineid & ATARI_TT) {
323 		/*
324 		 * ininitialise TT-MFP timer C: 307200Hz
325 		 * timer C and D share one control register:
326 		 *	bits 0-2 control timer D
327 		 *	bits 4-6 control timer C
328 		 */
329 		int cr = MFP2->mf_tcdcr & 7;
330 		MFP2->mf_tcdcr = cr;		/* stop timer C  */
331 		MFP2->mf_tcdr  = 1;		/* counter 1     */
332 		cr |= T_Q004 << 4;		/* divisor 4     */
333 		MFP2->mf_tcdcr = cr;		/* start timer C */
334 		/*
335 		 * enable scc related interrupts
336 		 */
337 		SCU->vme_mask |= SCU_SCC;
338 
339 		zs_frequencies = zs_freqs_tt;
340 	} else if (machineid & ATARI_FALCON) {
341 		zs_frequencies = zs_freqs_falcon;
342 	} else if (machineid & ATARI_HADES) {
343 		zs_frequencies = zs_freqs_hades;
344 	} else {
345 		zs_frequencies = zs_freqs_generic;
346 	}
347 
348 	/* link into interrupt list with order (A,B) (B=A+1) */
349 	cs[0].cs_next = &cs[1];
350 	cs[1].cs_next = zslist;
351 	zslist        = cs;
352 
353 	cs->cs_unit  = 0;
354 	cs->cs_zc    = &addr->zs_chan[ZS_CHAN_A];
355 	cs++;
356 	cs->cs_unit  = 1;
357 	cs->cs_zc    = &addr->zs_chan[ZS_CHAN_B];
358 
359 	printf(": serial2 on channel a and modem2 on channel b\n");
360 }
361 
362 /*
363  * Open a zs serial port.
364  */
365 int
366 zsopen(dev, flags, mode, l)
367 dev_t		dev;
368 int		flags;
369 int		mode;
370 struct lwp	*l;
371 {
372 	register struct tty		*tp;
373 	register struct zs_chanstate	*cs;
374 		 struct zs_softc	*zi;
375 		 int			unit = ZS_UNIT(dev);
376 		 int			zs = unit >> 1;
377 		 int			error, s;
378 
379 	if(zs >= zs_cd.cd_ndevs || (zi = zs_cd.cd_devs[zs]) == NULL)
380 		return (ENXIO);
381 	cs = &zi->zi_cs[unit & 1];
382 
383 	/*
384 	 * When port A (ser02) is selected on the TT, make sure
385 	 * the port is enabled.
386 	 */
387 	if((machineid & ATARI_TT) && !(unit & 1))
388 		ym2149_ser2(1);
389 
390 	if (cs->cs_rbuf == NULL) {
391 		cs->cs_rbuf = malloc(ZLRB_RING_SIZE * sizeof(int), M_DEVBUF,
392 								   M_WAITOK);
393 	}
394 
395 	tp = cs->cs_ttyp;
396 	if(tp == NULL) {
397 		cs->cs_ttyp = tp = ttymalloc();
398 		tty_attach(tp);
399 		tp->t_dev   = dev;
400 		tp->t_oproc = zsstart;
401 		tp->t_param = zsparam;
402 	}
403 
404 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
405 		return (EBUSY);
406 
407 	s  = spltty();
408 
409 	/*
410 	 * Do the following iff this is a first open.
411 	 */
412 	if (!(tp->t_state & TS_ISOPEN) && tp->t_wopen == 0) {
413 		if(tp->t_ispeed == 0) {
414 			tp->t_iflag = TTYDEF_IFLAG;
415 			tp->t_oflag = TTYDEF_OFLAG;
416 			tp->t_cflag = TTYDEF_CFLAG;
417 			tp->t_lflag = TTYDEF_LFLAG;
418 			tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
419 		}
420 		ttychars(tp);
421 		ttsetwater(tp);
422 
423 		(void)zsparam(tp, &tp->t_termios);
424 
425 		/*
426 		 * Turn on DTR.  We must always do this, even if carrier is not
427 		 * present, because otherwise we'd have to use TIOCSDTR
428 		 * immediately after setting CLOCAL, which applications do not
429 		 * expect.  We always assert DTR while the device is open
430 		 * unless explicitly requested to deassert it.
431 		 */
432 		zs_modem(cs, ZSWR5_RTS|ZSWR5_DTR, DMSET);
433 		/* May never get a status intr. if DCD already on. -gwr */
434 		if((cs->cs_rr0 = cs->cs_zc->zc_csr) & ZSRR0_DCD)
435 			tp->t_state |= TS_CARR_ON;
436 		if(cs->cs_softcar)
437 			tp->t_state |= TS_CARR_ON;
438 	}
439 
440 	splx(s);
441 
442 	error = ttyopen(tp, ZS_DIALOUT(dev), (flags & O_NONBLOCK));
443 	if (error)
444 		goto bad;
445 
446 	error = tp->t_linesw->l_open(dev, tp);
447 	if(error)
448 		goto bad;
449 	return (0);
450 
451 bad:
452 	if (!(tp->t_state & TS_ISOPEN) && tp->t_wopen == 0) {
453 		/*
454 		 * We failed to open the device, and nobody else had it opened.
455 		 * Clean up the state as appropriate.
456 		 */
457 		zs_shutdown(cs);
458 	}
459 	return(error);
460 }
461 
462 /*
463  * Close a zs serial port.
464  */
465 int
466 zsclose(dev, flags, mode, l)
467 dev_t		dev;
468 int		flags;
469 int		mode;
470 struct lwp	*l;
471 {
472 	register struct zs_chanstate	*cs;
473 	register struct tty		*tp;
474 		 struct zs_softc	*zi;
475 		 int			unit = ZS_UNIT(dev);
476 
477 	zi = zs_cd.cd_devs[unit >> 1];
478 	cs = &zi->zi_cs[unit & 1];
479 	tp = cs->cs_ttyp;
480 
481 	tp->t_linesw->l_close(tp, flags);
482 	ttyclose(tp);
483 
484 	if (!(tp->t_state & TS_ISOPEN) && tp->t_wopen == 0) {
485 		/*
486 		 * Although we got a last close, the device may still be in
487 		 * use; e.g. if this was the dialout node, and there are still
488 		 * processes waiting for carrier on the non-dialout node.
489 		 */
490 		zs_shutdown(cs);
491 	}
492 	return (0);
493 }
494 
495 /*
496  * Read/write zs serial port.
497  */
498 int
499 zsread(dev, uio, flags)
500 dev_t		dev;
501 struct uio	*uio;
502 int		flags;
503 {
504 	register struct zs_chanstate	*cs;
505 	register struct zs_softc	*zi;
506 	register struct tty		*tp;
507 		 int			unit;
508 
509 	unit = ZS_UNIT(dev);
510 	zi   = zs_cd.cd_devs[unit >> 1];
511 	cs   = &zi->zi_cs[unit & 1];
512 	tp   = cs->cs_ttyp;
513 
514 	return(tp->t_linesw->l_read(tp, uio, flags));
515 }
516 
517 int
518 zswrite(dev, uio, flags)
519 dev_t		dev;
520 struct uio	*uio;
521 int		flags;
522 {
523 	register struct zs_chanstate	*cs;
524 	register struct zs_softc	*zi;
525 	register struct tty		*tp;
526 		 int			unit;
527 
528 	unit = ZS_UNIT(dev);
529 	zi   = zs_cd.cd_devs[unit >> 1];
530 	cs   = &zi->zi_cs[unit & 1];
531 	tp   = cs->cs_ttyp;
532 
533 	return(tp->t_linesw->l_write(tp, uio, flags));
534 }
535 
536 int
537 zspoll(dev, events, l)
538 dev_t		dev;
539 int		events;
540 struct lwp	*l;
541 {
542 	register struct zs_chanstate	*cs;
543 	register struct zs_softc	*zi;
544 	register struct tty		*tp;
545 		 int			unit;
546 
547 	unit = ZS_UNIT(dev);
548 	zi   = zs_cd.cd_devs[unit >> 1];
549 	cs   = &zi->zi_cs[unit & 1];
550 	tp   = cs->cs_ttyp;
551 
552 	return ((*tp->t_linesw->l_poll)(tp, events, l));
553 }
554 
555 struct tty *
556 zstty(dev)
557 dev_t	dev;
558 {
559 	register struct zs_chanstate	*cs;
560 	register struct zs_softc	*zi;
561 		 int			unit;
562 
563 	unit = ZS_UNIT(dev);
564 	zi   = zs_cd.cd_devs[unit >> 1];
565 	cs   = &zi->zi_cs[unit & 1];
566 	return(cs->cs_ttyp);
567 }
568 
569 /*
570  * ZS hardware interrupt.  Scan all ZS channels.  NB: we know here that
571  * channels are kept in (A,B) pairs.
572  *
573  * Do just a little, then get out; set a software interrupt if more
574  * work is needed.
575  *
576  * We deliberately ignore the vectoring Zilog gives us, and match up
577  * only the number of `reset interrupt under service' operations, not
578  * the order.
579  */
580 
581 int
582 zshard(sr)
583 long sr;
584 {
585 	register struct zs_chanstate	*a;
586 #define	b (a + 1)
587 	register volatile struct zschan *zc;
588 	register int			rr3, intflags = 0, v, i;
589 
590 	do {
591 	    intflags &= ~4;
592 	    for(a = zslist; a != NULL; a = b->cs_next) {
593 		rr3 = ZS_READ(a->cs_zc, 3);
594 		if(rr3 & (ZSRR3_IP_A_RX|ZSRR3_IP_A_TX|ZSRR3_IP_A_STAT)) {
595 			intflags |= 4|2;
596 			zc = a->cs_zc;
597 			i  = a->cs_rbput;
598 			if(rr3 & ZSRR3_IP_A_RX && (v = zsrint(a, zc)) != 0) {
599 				a->cs_rbuf[i++ & ZLRB_RING_MASK] = v;
600 				intflags |= 1;
601 			}
602 			if(rr3 & ZSRR3_IP_A_TX && (v = zsxint(a, zc)) != 0) {
603 				a->cs_rbuf[i++ & ZLRB_RING_MASK] = v;
604 				intflags |= 1;
605 			}
606 			if(rr3 & ZSRR3_IP_A_STAT && (v = zssint(a, zc)) != 0) {
607 				a->cs_rbuf[i++ & ZLRB_RING_MASK] = v;
608 				intflags |= 1;
609 			}
610 			a->cs_rbput = i;
611 		}
612 		if(rr3 & (ZSRR3_IP_B_RX|ZSRR3_IP_B_TX|ZSRR3_IP_B_STAT)) {
613 			intflags |= 4|2;
614 			zc = b->cs_zc;
615 			i  = b->cs_rbput;
616 			if(rr3 & ZSRR3_IP_B_RX && (v = zsrint(b, zc)) != 0) {
617 				b->cs_rbuf[i++ & ZLRB_RING_MASK] = v;
618 				intflags |= 1;
619 			}
620 			if(rr3 & ZSRR3_IP_B_TX && (v = zsxint(b, zc)) != 0) {
621 				b->cs_rbuf[i++ & ZLRB_RING_MASK] = v;
622 				intflags |= 1;
623 			}
624 			if(rr3 & ZSRR3_IP_B_STAT && (v = zssint(b, zc)) != 0) {
625 				b->cs_rbuf[i++ & ZLRB_RING_MASK] = v;
626 				intflags |= 1;
627 			}
628 			b->cs_rbput = i;
629 		}
630 	    }
631 	} while(intflags & 4);
632 #undef b
633 
634 	if(intflags & 1) {
635 		if(BASEPRI(sr)) {
636 			spl1();
637 			zsshortcuts++;
638 			return(zssoft(sr));
639 		}
640 		else if(!cb_scheduled) {
641 			cb_scheduled++;
642 			add_sicallback((si_farg)zssoft, 0, 0);
643 		}
644 	}
645 	return(intflags & 2);
646 }
647 
648 static int
649 zsrint(cs, zc)
650 register struct zs_chanstate	*cs;
651 register volatile struct zschan	*zc;
652 {
653 	register int c;
654 
655 	/*
656 	 * First read the status, because read of the received char
657 	 * destroy the status of this char.
658 	 */
659 	c = ZS_READ(zc, 1);
660 	c |= (zc->zc_data << 8);
661 
662 	/* clear receive error & interrupt condition */
663 	zc->zc_csr = ZSWR0_RESET_ERRORS;
664 	zc->zc_csr = ZSWR0_CLR_INTR;
665 
666 	return(ZRING_MAKE(ZRING_RINT, c));
667 }
668 
669 static int
670 zsxint(cs, zc)
671 register struct zs_chanstate	*cs;
672 register volatile struct zschan	*zc;
673 {
674 	register int i = cs->cs_tbc;
675 
676 	if(i == 0) {
677 		zc->zc_csr = ZSWR0_RESET_TXINT;
678 		zc->zc_csr = ZSWR0_CLR_INTR;
679 		return(ZRING_MAKE(ZRING_XINT, 0));
680 	}
681 	cs->cs_tbc = i - 1;
682 	zc->zc_data = *cs->cs_tba++;
683 	zc->zc_csr = ZSWR0_CLR_INTR;
684 	return (0);
685 }
686 
687 static int
688 zssint(cs, zc)
689 register struct zs_chanstate	*cs;
690 register volatile struct zschan	*zc;
691 {
692 	register int rr0;
693 
694 	rr0 = zc->zc_csr;
695 	zc->zc_csr = ZSWR0_RESET_STATUS;
696 	zc->zc_csr = ZSWR0_CLR_INTR;
697 	/*
698 	 * The chip's hardware flow control is, as noted in zsreg.h,
699 	 * busted---if the DCD line goes low the chip shuts off the
700 	 * receiver (!).  If we want hardware CTS flow control but do
701 	 * not have it, and carrier is now on, turn HFC on; if we have
702 	 * HFC now but carrier has gone low, turn it off.
703 	 */
704 	if(rr0 & ZSRR0_DCD) {
705 		if(cs->cs_ttyp->t_cflag & CCTS_OFLOW &&
706 		    (cs->cs_creg[3] & ZSWR3_HFC) == 0) {
707 			cs->cs_creg[3] |= ZSWR3_HFC;
708 			ZS_WRITE(zc, 3, cs->cs_creg[3]);
709 		}
710 	}
711 	else {
712 		if (cs->cs_creg[3] & ZSWR3_HFC) {
713 			cs->cs_creg[3] &= ~ZSWR3_HFC;
714 			ZS_WRITE(zc, 3, cs->cs_creg[3]);
715 		}
716 	}
717 	return(ZRING_MAKE(ZRING_SINT, rr0));
718 }
719 
720 /*
721  * Print out a ring or fifo overrun error message.
722  */
723 static void
724 zsoverrun(unit, ptime, what)
725 int	unit;
726 long	*ptime;
727 const char *what;
728 {
729 
730 	if(*ptime != time.tv_sec) {
731 		*ptime = time.tv_sec;
732 		log(LOG_WARNING, "zs%d%c: %s overrun\n", unit >> 1,
733 		    (unit & 1) + 'a', what);
734 	}
735 }
736 
737 /*
738  * ZS software interrupt.  Scan all channels for deferred interrupts.
739  */
740 int
741 zssoft(sr)
742 long sr;
743 {
744     register struct zs_chanstate	*cs;
745     register volatile struct zschan	*zc;
746     register struct linesw		*line;
747     register struct tty			*tp;
748     register int			get, n, c, cc, unit, s;
749  	     int			retval = 0;
750 
751     cb_scheduled = 0;
752     s = spltty();
753     for(cs = zslist; cs != NULL; cs = cs->cs_next) {
754 	get = cs->cs_rbget;
755 again:
756 	n = cs->cs_rbput;	/* atomic			*/
757 	if(get == n)		/* nothing more on this line	*/
758 		continue;
759 	retval = 1;
760 	unit   = cs->cs_unit;	/* set up to handle interrupts	*/
761 	zc     = cs->cs_zc;
762 	tp     = cs->cs_ttyp;
763 	line   = tp->t_linesw;
764 	/*
765 	 * Compute the number of interrupts in the receive ring.
766 	 * If the count is overlarge, we lost some events, and
767 	 * must advance to the first valid one.  It may get
768 	 * overwritten if more data are arriving, but this is
769 	 * too expensive to check and gains nothing (we already
770 	 * lost out; all we can do at this point is trade one
771 	 * kind of loss for another).
772 	 */
773 	n -= get;
774 	if(n > ZLRB_RING_SIZE) {
775 		zsoverrun(unit, &cs->cs_rotime, "ring");
776 		get += n - ZLRB_RING_SIZE;
777 		n    = ZLRB_RING_SIZE;
778 	}
779 	while(--n >= 0) {
780 		/* race to keep ahead of incoming interrupts */
781 		c = cs->cs_rbuf[get++ & ZLRB_RING_MASK];
782 		switch (ZRING_TYPE(c)) {
783 
784 		case ZRING_RINT:
785 			c = ZRING_VALUE(c);
786 			if(c & ZSRR1_DO)
787 				zsoverrun(unit, &cs->cs_fotime, "fifo");
788 			cc = c >> 8;
789 			if(c & ZSRR1_FE)
790 				cc |= TTY_FE;
791 			if(c & ZSRR1_PE)
792 				cc |= TTY_PE;
793 			line->l_rint(cc, tp);
794 			break;
795 
796 		case ZRING_XINT:
797 			/*
798 			 * Transmit done: change registers and resume,
799 			 * or clear BUSY.
800 			 */
801 			if(cs->cs_heldchange) {
802 				int sps;
803 
804 				sps = splzs();
805 				c = zc->zc_csr;
806 				if((c & ZSRR0_DCD) == 0)
807 					cs->cs_preg[3] &= ~ZSWR3_HFC;
808 				bcopy((void *)cs->cs_preg,
809 				    (void *)cs->cs_creg, 16);
810 				zs_loadchannelregs(zc, cs->cs_creg);
811 				splx(sps);
812 				cs->cs_heldchange = 0;
813 				if(cs->cs_heldtbc
814 					&& (tp->t_state & TS_TTSTOP) == 0) {
815 					cs->cs_tbc = cs->cs_heldtbc - 1;
816 					zc->zc_data = *cs->cs_tba++;
817 					goto again;
818 				}
819 			}
820 			tp->t_state &= ~TS_BUSY;
821 			if(tp->t_state & TS_FLUSH)
822 				tp->t_state &= ~TS_FLUSH;
823 			else ndflush(&tp->t_outq,cs->cs_tba
824 						- tp->t_outq.c_cf);
825 			line->l_start(tp);
826 			break;
827 
828 		case ZRING_SINT:
829 			/*
830 			 * Status line change.  HFC bit is run in
831 			 * hardware interrupt, to avoid locking
832 			 * at splzs here.
833 			 */
834 			c = ZRING_VALUE(c);
835 			if((c ^ cs->cs_rr0) & ZSRR0_DCD) {
836 				cc = (c & ZSRR0_DCD) != 0;
837 				if(line->l_modem(tp, cc) == 0)
838 					zs_modem(cs, ZSWR5_RTS|ZSWR5_DTR,
839 							cc ? DMBIS : DMBIC);
840 			}
841 			cs->cs_rr0 = c;
842 			break;
843 
844 		default:
845 			log(LOG_ERR, "zs%d%c: bad ZRING_TYPE (%x)\n",
846 			    unit >> 1, (unit & 1) + 'a', c);
847 			break;
848 		}
849 	}
850 	cs->cs_rbget = get;
851 	goto again;
852     }
853     splx(s);
854     return (retval);
855 }
856 
857 int
858 zsioctl(dev, cmd, data, flag, l)
859 dev_t		dev;
860 u_long		cmd;
861 void *		data;
862 int		flag;
863 struct lwp	*l;
864 {
865 		 int			unit = ZS_UNIT(dev);
866 		 struct zs_softc	*zi = zs_cd.cd_devs[unit >> 1];
867 	register struct tty		*tp = zi->zi_cs[unit & 1].cs_ttyp;
868 	register int			error, s;
869 	register struct zs_chanstate	*cs = &zi->zi_cs[unit & 1];
870 
871 	error = tp->t_linesw->l_ioctl(tp, cmd, data, flag, l);
872 	if(error != EPASSTHROUGH)
873 		return(error);
874 
875 	error = ttioctl(tp, cmd, data, flag, l);
876 	if(error !=EPASSTHROUGH)
877 		return (error);
878 
879 	switch (cmd) {
880 	case TIOCSBRK:
881 		s = splzs();
882 		cs->cs_preg[5] |= ZSWR5_BREAK;
883 		cs->cs_creg[5] |= ZSWR5_BREAK;
884 		ZS_WRITE(cs->cs_zc, 5, cs->cs_creg[5]);
885 		splx(s);
886 		break;
887 	case TIOCCBRK:
888 		s = splzs();
889 		cs->cs_preg[5] &= ~ZSWR5_BREAK;
890 		cs->cs_creg[5] &= ~ZSWR5_BREAK;
891 		ZS_WRITE(cs->cs_zc, 5, cs->cs_creg[5]);
892 		splx(s);
893 		break;
894 	case TIOCGFLAGS: {
895 		int bits = 0;
896 
897 		if(cs->cs_softcar)
898 			bits |= TIOCFLAG_SOFTCAR;
899 		if(cs->cs_creg[15] & ZSWR15_DCD_IE)
900 			bits |= TIOCFLAG_CLOCAL;
901 		if(cs->cs_creg[3] & ZSWR3_HFC)
902 			bits |= TIOCFLAG_CRTSCTS;
903 		*(int *)data = bits;
904 		break;
905 	}
906 	case TIOCSFLAGS: {
907 		int userbits = 0;
908 
909 		error = kauth_authorize_device_tty(l->l_cred,
910 		    KAUTH_DEVICE_TTY_PRIVSET, tp);
911 		if(error != 0)
912 			return (EPERM);
913 
914 		userbits = *(int *)data;
915 
916 		/*
917 		 * can have `local' or `softcar', and `rtscts' or `mdmbuf'
918 		 # defaulting to software flow control.
919 		 */
920 		if(userbits & TIOCFLAG_SOFTCAR && userbits & TIOCFLAG_CLOCAL)
921 			return(EINVAL);
922 		if(userbits & TIOCFLAG_MDMBUF)	/* don't support this (yet?) */
923 			return(ENODEV);
924 
925 		s = splzs();
926 		if((userbits & TIOCFLAG_SOFTCAR)) {
927 			cs->cs_softcar = 1;	/* turn on softcar */
928 			cs->cs_preg[15] &= ~ZSWR15_DCD_IE; /* turn off dcd */
929 			cs->cs_creg[15] &= ~ZSWR15_DCD_IE;
930 			ZS_WRITE(cs->cs_zc, 15, cs->cs_creg[15]);
931 		}
932 		else if(userbits & TIOCFLAG_CLOCAL) {
933 			cs->cs_softcar = 0; 	/* turn off softcar */
934 			cs->cs_preg[15] |= ZSWR15_DCD_IE; /* turn on dcd */
935 			cs->cs_creg[15] |= ZSWR15_DCD_IE;
936 			ZS_WRITE(cs->cs_zc, 15, cs->cs_creg[15]);
937 			tp->t_termios.c_cflag |= CLOCAL;
938 		}
939 		if(userbits & TIOCFLAG_CRTSCTS) {
940 			cs->cs_preg[15] |= ZSWR15_CTS_IE;
941 			cs->cs_creg[15] |= ZSWR15_CTS_IE;
942 			ZS_WRITE(cs->cs_zc, 15, cs->cs_creg[15]);
943 			cs->cs_preg[3] |= ZSWR3_HFC;
944 			cs->cs_creg[3] |= ZSWR3_HFC;
945 			ZS_WRITE(cs->cs_zc, 3, cs->cs_creg[3]);
946 			tp->t_termios.c_cflag |= CRTSCTS;
947 		}
948 		else {
949 			/* no mdmbuf, so we must want software flow control */
950 			cs->cs_preg[15] &= ~ZSWR15_CTS_IE;
951 			cs->cs_creg[15] &= ~ZSWR15_CTS_IE;
952 			ZS_WRITE(cs->cs_zc, 15, cs->cs_creg[15]);
953 			cs->cs_preg[3] &= ~ZSWR3_HFC;
954 			cs->cs_creg[3] &= ~ZSWR3_HFC;
955 			ZS_WRITE(cs->cs_zc, 3, cs->cs_creg[3]);
956 			tp->t_termios.c_cflag &= ~CRTSCTS;
957 		}
958 		splx(s);
959 		break;
960 	}
961 	case TIOCSDTR:
962 		zs_modem(cs, ZSWR5_DTR, DMBIS);
963 		break;
964 	case TIOCCDTR:
965 		zs_modem(cs, ZSWR5_DTR, DMBIC);
966 		break;
967 	case TIOCMGET:
968 		zs_modem(cs, 0, DMGET);
969 		break;
970 	case TIOCMSET:
971 	case TIOCMBIS:
972 	case TIOCMBIC:
973 	default:
974 		return (EPASSTHROUGH);
975 	}
976 	return (0);
977 }
978 
979 /*
980  * Start or restart transmission.
981  */
982 static void
983 zsstart(tp)
984 register struct tty *tp;
985 {
986 	register struct zs_chanstate	*cs;
987 	register int			s, nch;
988 		 int			unit = ZS_UNIT(tp->t_dev);
989 		 struct zs_softc	*zi = zs_cd.cd_devs[unit >> 1];
990 
991 	cs = &zi->zi_cs[unit & 1];
992 	s  = spltty();
993 
994 	/*
995 	 * If currently active or delaying, no need to do anything.
996 	 */
997 	if(tp->t_state & (TS_TIMEOUT | TS_BUSY | TS_TTSTOP))
998 		goto out;
999 
1000 	/*
1001 	 * If there are sleepers, and output has drained below low
1002 	 * water mark, awaken.
1003 	 */
1004 	ttypull(tp);
1005 
1006 	nch = ndqb(&tp->t_outq, 0);	/* XXX */
1007 	if(nch) {
1008 		register char *p = tp->t_outq.c_cf;
1009 
1010 		/* mark busy, enable tx done interrupts, & send first byte */
1011 		tp->t_state |= TS_BUSY;
1012 		(void) splzs();
1013 		cs->cs_preg[1] |= ZSWR1_TIE;
1014 		cs->cs_creg[1] |= ZSWR1_TIE;
1015 		ZS_WRITE(cs->cs_zc, 1, cs->cs_creg[1]);
1016 		cs->cs_zc->zc_data = *p;
1017 		cs->cs_tba = p + 1;
1018 		cs->cs_tbc = nch - 1;
1019 	} else {
1020 		/*
1021 		 * Nothing to send, turn off transmit done interrupts.
1022 		 * This is useful if something is doing polled output.
1023 		 */
1024 		(void) splzs();
1025 		cs->cs_preg[1] &= ~ZSWR1_TIE;
1026 		cs->cs_creg[1] &= ~ZSWR1_TIE;
1027 		ZS_WRITE(cs->cs_zc, 1, cs->cs_creg[1]);
1028 	}
1029 out:
1030 	splx(s);
1031 }
1032 
1033 /*
1034  * Stop output, e.g., for ^S or output flush.
1035  */
1036 void
1037 zsstop(tp, flag)
1038 register struct tty	*tp;
1039 	 int		flag;
1040 {
1041 	register struct zs_chanstate	*cs;
1042 	register int			s, unit = ZS_UNIT(tp->t_dev);
1043 		 struct zs_softc	*zi = zs_cd.cd_devs[unit >> 1];
1044 
1045 	cs = &zi->zi_cs[unit & 1];
1046 	s  = splzs();
1047 	if(tp->t_state & TS_BUSY) {
1048 		/*
1049 		 * Device is transmitting; must stop it.
1050 		 */
1051 		cs->cs_tbc = 0;
1052 		if ((tp->t_state & TS_TTSTOP) == 0)
1053 			tp->t_state |= TS_FLUSH;
1054 	}
1055 	splx(s);
1056 }
1057 
1058 static void
1059 zs_shutdown(cs)
1060 	struct zs_chanstate	*cs;
1061 {
1062 	struct tty	*tp = cs->cs_ttyp;
1063 	int		s;
1064 
1065 	s = splzs();
1066 
1067 	/*
1068 	 * Hang up if necessary.  Wait a bit, so the other side has time to
1069 	 * notice even if we immediately open the port again.
1070 	 */
1071 	if(tp->t_cflag & HUPCL) {
1072 		zs_modem(cs, 0, DMSET);
1073 		(void)tsleep((void *)cs, TTIPRI, ttclos, hz);
1074 	}
1075 
1076 	/* Clear any break condition set with TIOCSBRK. */
1077 	if(cs->cs_creg[5] & ZSWR5_BREAK) {
1078 		cs->cs_preg[5] &= ~ZSWR5_BREAK;
1079 		cs->cs_creg[5] &= ~ZSWR5_BREAK;
1080 		ZS_WRITE(cs->cs_zc, 5, cs->cs_creg[5]);
1081 	}
1082 
1083 	/*
1084 	 * Drop all lines and cancel interrupts
1085 	 */
1086 	zs_loadchannelregs(cs->cs_zc, zs_init_regs);
1087 	splx(s);
1088 }
1089 
1090 /*
1091  * Set ZS tty parameters from termios.
1092  *
1093  * This routine makes use of the fact that only registers
1094  * 1, 3, 4, 5, 9, 10, 11, 12, 13, 14, and 15 are written.
1095  */
1096 static int
1097 zsparam(tp, t)
1098 register struct tty	*tp;
1099 register struct termios	*t;
1100 {
1101 		 int			unit = ZS_UNIT(tp->t_dev);
1102 		 struct zs_softc	*zi = zs_cd.cd_devs[unit >> 1];
1103 	register struct zs_chanstate	*cs = &zi->zi_cs[unit & 1];
1104 		 int			cdiv = 0,	/* XXX gcc4 -Wuninitialized */
1105 					clkm = 0,	/* XXX gcc4 -Wuninitialized */
1106 					brgm = 0,	/* XXX gcc4 -Wuninitialized */
1107 					tcon = 0;	/* XXX gcc4 -Wuninitialized */
1108 	register int			tmp, tmp5, cflag, s;
1109 
1110 	tmp  = t->c_ospeed;
1111 	tmp5 = t->c_ispeed;
1112 	if(tmp < 0 || (tmp5 && tmp5 != tmp))
1113 		return(EINVAL);
1114 	if(tmp == 0) {
1115 		/* stty 0 => drop DTR and RTS */
1116 		zs_modem(cs, 0, DMSET);
1117 		return(0);
1118 	}
1119 	tmp = zsbaudrate(unit, tmp, &cdiv, &clkm, &brgm, &tcon);
1120 	if (tmp < 0)
1121 		return(EINVAL);
1122 	tp->t_ispeed = tp->t_ospeed = tmp;
1123 
1124 	cflag = tp->t_cflag = t->c_cflag;
1125 	if (cflag & CSTOPB)
1126 		cdiv |= ZSWR4_TWOSB;
1127 	else
1128 		cdiv |= ZSWR4_ONESB;
1129 	if (!(cflag & PARODD))
1130 		cdiv |= ZSWR4_EVENP;
1131 	if (cflag & PARENB)
1132 		cdiv |= ZSWR4_PARENB;
1133 
1134 	switch(cflag & CSIZE) {
1135 	case CS5:
1136 		tmp  = ZSWR3_RX_5;
1137 		tmp5 = ZSWR5_TX_5;
1138 		break;
1139 	case CS6:
1140 		tmp  = ZSWR3_RX_6;
1141 		tmp5 = ZSWR5_TX_6;
1142 		break;
1143 	case CS7:
1144 		tmp  = ZSWR3_RX_7;
1145 		tmp5 = ZSWR5_TX_7;
1146 		break;
1147 	case CS8:
1148 	default:
1149 		tmp  = ZSWR3_RX_8;
1150 		tmp5 = ZSWR5_TX_8;
1151 		break;
1152 	}
1153 	tmp  |= ZSWR3_RX_ENABLE;
1154 	tmp5 |= ZSWR5_TX_ENABLE | ZSWR5_DTR | ZSWR5_RTS;
1155 
1156 	/*
1157 	 * Block interrupts so that state will not
1158 	 * be altered until we are done setting it up.
1159 	 */
1160 	s = splzs();
1161 	cs->cs_preg[4]  = cdiv;
1162 	cs->cs_preg[11] = clkm;
1163 	cs->cs_preg[12] = tcon;
1164 	cs->cs_preg[13] = tcon >> 8;
1165 	cs->cs_preg[14] = brgm;
1166 	cs->cs_preg[1]  = ZSWR1_RIE | ZSWR1_TIE | ZSWR1_SIE;
1167 	cs->cs_preg[9]  = ZSWR9_MASTER_IE | ZSWR9_VECTOR_INCL_STAT;
1168 	cs->cs_preg[10] = ZSWR10_NRZ;
1169 	cs->cs_preg[15] = ZSWR15_BREAK_IE | ZSWR15_DCD_IE;
1170 
1171 	/*
1172 	 * Output hardware flow control on the chip is horrendous: if
1173 	 * carrier detect drops, the receiver is disabled.  Hence we
1174 	 * can only do this when the carrier is on.
1175 	 */
1176 	if(cflag & CCTS_OFLOW && cs->cs_zc->zc_csr & ZSRR0_DCD)
1177 		tmp |= ZSWR3_HFC;
1178 	cs->cs_preg[3] = tmp;
1179 	cs->cs_preg[5] = tmp5;
1180 
1181 	/*
1182 	 * If nothing is being transmitted, set up new current values,
1183 	 * else mark them as pending.
1184 	 */
1185 	if(cs->cs_heldchange == 0) {
1186 		if (cs->cs_ttyp->t_state & TS_BUSY) {
1187 			cs->cs_heldtbc = cs->cs_tbc;
1188 			cs->cs_tbc = 0;
1189 			cs->cs_heldchange = 1;
1190 		} else {
1191 			bcopy((void *)cs->cs_preg, (void *)cs->cs_creg, 16);
1192 			zs_loadchannelregs(cs->cs_zc, cs->cs_creg);
1193 		}
1194 	}
1195 	splx(s);
1196 	return (0);
1197 }
1198 
1199 /*
1200  * search for the best matching baudrate
1201  */
1202 static int
1203 zsbaudrate(unit, wanted, divisor, clockmode, brgenmode, timeconst)
1204 int	unit, wanted, *divisor, *clockmode, *brgenmode, *timeconst;
1205 {
1206 	int	bestdiff, bestbps, source;
1207 
1208 	bestdiff = bestbps = 0;
1209 	unit = (unit & 1) << 2;
1210 	for (source = 0; source < 4; ++source) {
1211 		long	freq = zs_frequencies[unit + source];
1212 		int	diff, bps, div, clkm, brgm, tcon;
1213 
1214 		bps = div = clkm = brgm = tcon = 0;
1215 		switch (source) {
1216 			case 0:	/* BRgen, PCLK */
1217 				brgm = ZSWR14_BAUD_ENA|ZSWR14_BAUD_FROM_PCLK;
1218 				break;
1219 			case 1:	/* BRgen, RTxC */
1220 				brgm = ZSWR14_BAUD_ENA;
1221 				break;
1222 			case 2: /* RTxC */
1223 				clkm = ZSWR11_RXCLK_RTXC|ZSWR11_TXCLK_RTXC;
1224 				break;
1225 			case 3: /* TRxC */
1226 				clkm = ZSWR11_RXCLK_TRXC|ZSWR11_TXCLK_TRXC;
1227 				break;
1228 		}
1229 		switch (source) {
1230 			case 0:
1231 			case 1:
1232 				div  = ZSWR4_CLK_X16;
1233 				clkm = ZSWR11_RXCLK_BAUD|ZSWR11_TXCLK_BAUD;
1234 				tcon = BPS_TO_TCONST(freq, wanted);
1235 				if (tcon < 0)
1236 					tcon = 0;
1237 				bps  = TCONST_TO_BPS(freq, tcon);
1238 				break;
1239 			case 2:
1240 			case 3:
1241 			{	int	b1 = freq / 16, d1 = abs(b1 - wanted);
1242 				int	b2 = freq / 32, d2 = abs(b2 - wanted);
1243 				int	b3 = freq / 64, d3 = abs(b3 - wanted);
1244 
1245 				if (d1 < d2 && d1 < d3) {
1246 					div = ZSWR4_CLK_X16;
1247 					bps = b1;
1248 				} else if (d2 < d3 && d2 < d1) {
1249 					div = ZSWR4_CLK_X32;
1250 					bps = b2;
1251 				} else {
1252 					div = ZSWR4_CLK_X64;
1253 					bps = b3;
1254 				}
1255 				brgm = tcon = 0;
1256 				break;
1257 			}
1258 		}
1259 		diff = abs(bps - wanted);
1260 		if (!source || diff < bestdiff) {
1261 			*divisor   = div;
1262 			*clockmode = clkm;
1263 			*brgenmode = brgm;
1264 			*timeconst = tcon;
1265 			bestbps    = bps;
1266 			bestdiff   = diff;
1267 			if (diff == 0)
1268 				break;
1269 		}
1270 	}
1271 	/* Allow deviations upto 5% */
1272 	if (20 * bestdiff > wanted)
1273 		return -1;
1274 	return bestbps;
1275 }
1276 
1277 /*
1278  * Raise or lower modem control (DTR/RTS) signals.  If a character is
1279  * in transmission, the change is deferred.
1280  */
1281 static int
1282 zs_modem(cs, bits, how)
1283 struct zs_chanstate	*cs;
1284 int			bits, how;
1285 {
1286 	int s, mbits;
1287 
1288 	bits  &= ZSWR5_DTR | ZSWR5_RTS;
1289 
1290 	s = splzs();
1291 	mbits  = cs->cs_preg[5] &  (ZSWR5_DTR | ZSWR5_RTS);
1292 
1293 	switch(how) {
1294 		case DMSET:
1295 				mbits  = bits;
1296 				break;
1297 		case DMBIS:
1298 				mbits |= bits;
1299 				break;
1300 		case DMBIC:
1301 				mbits &= ~bits;
1302 				break;
1303 		case DMGET:
1304 				splx(s);
1305 				return(mbits);
1306 	}
1307 
1308 	cs->cs_preg[5] = (cs->cs_preg[5] & ~(ZSWR5_DTR | ZSWR5_RTS)) | mbits;
1309 	if(cs->cs_heldchange == 0) {
1310 		if(cs->cs_ttyp->t_state & TS_BUSY) {
1311 			cs->cs_heldtbc = cs->cs_tbc;
1312 			cs->cs_tbc = 0;
1313 			cs->cs_heldchange = 1;
1314 		}
1315 		else {
1316 			ZS_WRITE(cs->cs_zc, 5, cs->cs_creg[5]);
1317 		}
1318 	}
1319 	splx(s);
1320 	return(0);
1321 }
1322 
1323 /*
1324  * Write the given register set to the given zs channel in the proper order.
1325  * The channel must not be transmitting at the time.  The receiver will
1326  * be disabled for the time it takes to write all the registers.
1327  */
1328 static void
1329 zs_loadchannelregs(zc, reg)
1330 volatile struct zschan	*zc;
1331 u_char			*reg;
1332 {
1333 	int i;
1334 
1335 	zc->zc_csr = ZSM_RESET_ERR;	/* reset error condition */
1336 	i = zc->zc_data;		/* drain fifo */
1337 	i = zc->zc_data;
1338 	i = zc->zc_data;
1339 	ZS_WRITE(zc,  4, reg[4]);
1340 	ZS_WRITE(zc, 10, reg[10]);
1341 	ZS_WRITE(zc,  3, reg[3] & ~ZSWR3_RX_ENABLE);
1342 	ZS_WRITE(zc,  5, reg[5] & ~ZSWR5_TX_ENABLE);
1343 	ZS_WRITE(zc,  1, reg[1]);
1344 	ZS_WRITE(zc,  9, reg[9]);
1345 	ZS_WRITE(zc, 11, reg[11]);
1346 	ZS_WRITE(zc, 12, reg[12]);
1347 	ZS_WRITE(zc, 13, reg[13]);
1348 	ZS_WRITE(zc, 14, reg[14]);
1349 	ZS_WRITE(zc, 15, reg[15]);
1350 	ZS_WRITE(zc,  3, reg[3]);
1351 	ZS_WRITE(zc,  5, reg[5]);
1352 }
1353 #endif /* NZS > 1 */
1354