xref: /netbsd-src/sys/arch/luna68k/dev/siotty.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /* $NetBSD: siotty.c,v 1.21 2007/11/19 18:51:40 ad Exp $ */
2 
3 /*-
4  * Copyright (c) 2000 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Tohru Nishimura.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the NetBSD
21  *	Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
40 
41 __KERNEL_RCSID(0, "$NetBSD: siotty.c,v 1.21 2007/11/19 18:51:40 ad Exp $");
42 
43 #include "opt_ddb.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/device.h>
48 #include <sys/conf.h>
49 #include <sys/ioctl.h>
50 #include <sys/proc.h>
51 #include <sys/user.h>
52 #include <sys/tty.h>
53 #include <sys/uio.h>
54 #include <sys/callout.h>
55 #include <sys/fcntl.h>
56 #include <dev/cons.h>
57 #include <sys/kauth.h>
58 
59 #include <machine/cpu.h>
60 
61 #include <luna68k/dev/sioreg.h>
62 #include <luna68k/dev/siovar.h>
63 
64 #define	TIOCM_BREAK 01000 /* non standard use */
65 
66 static const u_int8_t ch0_regs[6] = {
67 	WR0_RSTINT,				/* reset E/S interrupt */
68 	WR1_RXALLS | WR1_TXENBL,	 	/* Rx per char, Tx */
69 	0,					/* */
70 	WR3_RX8BIT | WR3_RXENBL,		/* Rx */
71 	WR4_BAUD96 | WR4_STOP1,			/* Tx/Rx */
72 	WR5_TX8BIT | WR5_TXENBL | WR5_DTR | WR5_RTS, /* Tx */
73 };
74 
75 static const struct speedtab siospeedtab[] = {
76 	{ 2400,	WR4_BAUD24, },
77 	{ 4800,	WR4_BAUD48, },
78 	{ 9600,	WR4_BAUD96, },
79 	{ -1,	0, },
80 };
81 
82 struct siotty_softc {
83 	struct device	sc_dev;
84 	struct tty	*sc_tty;
85 	struct sioreg	*sc_ctl;
86 	u_int 		sc_flags;
87 	u_int8_t	sc_wr[6];
88 };
89 
90 #include "siotty.h"
91 static void siostart __P((struct tty *));
92 static int  sioparam __P((struct tty *, struct termios *));
93 static void siottyintr __P((int));
94 static int  siomctl __P((struct siotty_softc *, int, int));
95 
96 static int  siotty_match __P((struct device *, struct cfdata *, void *));
97 static void siotty_attach __P((struct device *, struct device *, void *));
98 
99 CFATTACH_DECL(siotty, sizeof(struct siotty_softc),
100     siotty_match, siotty_attach, NULL, NULL);
101 extern struct cfdriver siotty_cd;
102 
103 dev_type_open(sioopen);
104 dev_type_close(sioclose);
105 dev_type_read(sioread);
106 dev_type_write(siowrite);
107 dev_type_ioctl(sioioctl);
108 dev_type_stop(siostop);
109 dev_type_tty(siotty);
110 dev_type_poll(siopoll);
111 
112 const struct cdevsw siotty_cdevsw = {
113 	sioopen, sioclose, sioread, siowrite, sioioctl,
114 	siostop, siotty, siopoll, nommap, ttykqfilter, D_TTY
115 };
116 
117 static int
118 siotty_match(parent, cf, aux)
119 	struct device *parent;
120 	struct cfdata *cf;
121 	void   *aux;
122 {
123 	struct sio_attach_args *args = aux;
124 
125 	if (args->channel != 0) /* XXX allow tty on Ch.B XXX */
126 		return 0;
127 	return 1;
128 }
129 
130 static void
131 siotty_attach(parent, self, aux)
132 	struct device *parent, *self;
133 	void *aux;
134 {
135 	struct sio_softc *scp = (void *)parent;
136 	struct siotty_softc *sc = (void *)self;
137 	struct sio_attach_args *args = aux;
138 
139 	sc->sc_ctl = (struct sioreg *)scp->scp_ctl + args->channel;
140 	bcopy(ch0_regs, sc->sc_wr, sizeof(ch0_regs));
141 	scp->scp_intr[args->channel] = siottyintr;
142 
143 	if (args->hwflags == 1) {
144 		printf(" (console)");
145 		sc->sc_flags = TIOCFLAG_SOFTCAR;
146 	}
147 	else {
148 		setsioreg(sc->sc_ctl, WR0, WR0_CHANRST);
149 		setsioreg(sc->sc_ctl, WR2A, WR2_VEC86 | WR2_INTR_1);
150 		setsioreg(sc->sc_ctl, WR2B, 0);
151 		setsioreg(sc->sc_ctl, WR0, sc->sc_wr[WR0]);
152 		setsioreg(sc->sc_ctl, WR4, sc->sc_wr[WR4]);
153 		setsioreg(sc->sc_ctl, WR3, sc->sc_wr[WR3]);
154 		setsioreg(sc->sc_ctl, WR5, sc->sc_wr[WR5]);
155 		setsioreg(sc->sc_ctl, WR0, sc->sc_wr[WR0]);
156 	}
157 	setsioreg(sc->sc_ctl, WR1, sc->sc_wr[WR1]); /* now interrupt driven */
158 
159 	printf("\n");
160 }
161 
162 /*--------------------  low level routine --------------------*/
163 
164 static void
165 siottyintr(chan)
166 	int chan;
167 {
168 	struct siotty_softc *sc;
169 	struct sioreg *sio;
170 	struct tty *tp;
171 	unsigned int code;
172 	int rr;
173 
174 	if (chan >= siotty_cd.cd_ndevs)
175 		return;
176 	sc = siotty_cd.cd_devs[chan];
177 	tp = sc->sc_tty;
178 	sio = sc->sc_ctl;
179 	rr = getsiocsr(sio);
180 	if (rr & RR_RXRDY) {
181 		do {
182 			code = sio->sio_data;
183 			if (rr & (RR_FRAMING | RR_OVERRUN | RR_PARITY)) {
184 				sio->sio_cmd = WR0_ERRRST;
185 				if (sio->sio_stat & RR_FRAMING)
186 					code |= TTY_FE;
187 				else if (sio->sio_stat & RR_PARITY)
188 					code |= TTY_PE;
189 			}
190 			if (tp == NULL || (tp->t_state & TS_ISOPEN) == 0)
191 				continue;
192 #if 0 && defined(DDB) /* ?!?! fails to resume ?!?! */
193 			if ((rr & RR_BREAK) && tp->t_dev == cn_tab->cn_dev) {
194 				cpu_Debugger();
195 				return;
196 			}
197 #endif
198 			(*tp->t_linesw->l_rint)(code, tp);
199 		} while ((rr = getsiocsr(sio)) & RR_RXRDY);
200 	}
201 	if (rr & RR_TXRDY) {
202 		sio->sio_cmd = WR0_RSTPEND;
203 		if (tp != NULL) {
204 			tp->t_state &= ~(TS_BUSY|TS_FLUSH);
205 			(*tp->t_linesw->l_start)(tp);
206 		}
207 	}
208 }
209 
210 static void
211 siostart(tp)
212 	struct tty *tp;
213 {
214 	struct siotty_softc *sc = siotty_cd.cd_devs[minor(tp->t_dev)];
215 	int s, c;
216 
217 	s = spltty();
218 	if (tp->t_state & (TS_BUSY|TS_TIMEOUT|TS_TTSTOP))
219 		goto out;
220 	if (!ttypull(tp))
221 		goto out;
222 	tp->t_state |= TS_BUSY;
223 	while (getsiocsr(sc->sc_ctl) & RR_TXRDY) {
224 		if ((c = getc(&tp->t_outq)) == -1)
225 			break;
226 		sc->sc_ctl->sio_data = c;
227 	}
228 out:
229 	splx(s);
230 }
231 
232 void
233 siostop(tp, flag)
234 	struct tty *tp;
235 	int flag;
236 {
237 	int s;
238 
239         s = spltty();
240         if (TS_BUSY == (tp->t_state & (TS_BUSY|TS_TTSTOP))) {
241                 /*
242                  * Device is transmitting; must stop it.
243                  */
244 		tp->t_state |= TS_FLUSH;
245         }
246         splx(s);
247 }
248 
249 static int
250 sioparam(tp, t)
251 	struct tty *tp;
252 	struct termios *t;
253 {
254 	struct siotty_softc *sc = siotty_cd.cd_devs[minor(tp->t_dev)];
255 	int wr4, s;
256 
257 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
258 		return EINVAL;
259 	wr4 = ttspeedtab(t->c_ospeed, siospeedtab);
260 	if (wr4 < 0)
261 		return EINVAL;
262 
263 	if (sc->sc_flags & TIOCFLAG_SOFTCAR) {
264 		t->c_cflag |= CLOCAL;
265 		t->c_cflag &= ~HUPCL;
266 	}
267 	if (sc->sc_flags & TIOCFLAG_CLOCAL)
268 		t->c_cflag |= CLOCAL;
269 
270 	/*
271 	 * If there were no changes, don't do anything.  This avoids dropping
272 	 * input and improves performance when all we did was frob things like
273 	 * VMIN and VTIME.
274 	 */
275 	if (tp->t_ospeed == t->c_ospeed && tp->t_cflag == t->c_cflag)
276 		return 0;
277 
278 	tp->t_ispeed = t->c_ispeed;
279 	tp->t_ospeed = t->c_ospeed;
280 	tp->t_cflag = t->c_cflag;
281 
282 	sc->sc_wr[WR3] &= 0x3f;
283 	sc->sc_wr[WR5] &= 0x9f;
284 	switch (tp->t_cflag & CSIZE) {
285 	case CS7:
286 		sc->sc_wr[WR3] |= WR3_RX7BIT; sc->sc_wr[WR5] |= WR5_TX7BIT;
287 		break;
288 	case CS8:
289 		sc->sc_wr[WR3] |= WR3_RX8BIT; sc->sc_wr[WR5] |= WR5_TX8BIT;
290 		break;
291 	}
292 	if (tp->t_cflag & PARENB) {
293 		wr4 |= WR4_PARENAB;
294 		if ((tp->t_cflag & PARODD) == 0)
295 			wr4 |= WR4_EPARITY;
296 	}
297 	wr4 |= (tp->t_cflag & CSTOPB) ? WR4_STOP2 : WR4_STOP1;
298 	sc->sc_wr[WR4] = wr4;
299 
300 	s = spltty();
301 	setsioreg(sc->sc_ctl, WR4, sc->sc_wr[WR4]);
302 	setsioreg(sc->sc_ctl, WR3, sc->sc_wr[WR3]);
303 	setsioreg(sc->sc_ctl, WR5, sc->sc_wr[WR5]);
304 	splx(s);
305 
306 	return 0;
307 }
308 
309 static int
310 siomctl(sc, control, op)
311 	struct siotty_softc *sc;
312 	int control, op;
313 {
314 	int val, s, wr5, rr;
315 
316 	val = 0;
317 	if (control & TIOCM_BREAK)
318 		val |= WR5_BREAK;
319 	if (control & TIOCM_DTR)
320 		val |= WR5_DTR;
321 	if (control & TIOCM_RTS)
322 		val |= WR5_RTS;
323 	s = spltty();
324 	wr5 = sc->sc_wr[WR5];
325 	switch (op) {
326 	case DMSET:
327 		wr5 &= ~(WR5_BREAK|WR5_DTR|WR5_RTS);
328 		/* FALLTHRU */
329 	case DMBIS:
330 		wr5 |= val;
331 		break;
332 	case DMBIC:
333 		wr5 &= ~val;
334 		break;
335 	case DMGET:
336 		val = 0;
337 		rr = getsiocsr(sc->sc_ctl);
338 		if (wr5 & WR5_DTR)
339 			val |= TIOCM_DTR;
340 		if (wr5 & WR5_RTS)
341 			val |= TIOCM_RTS;
342 		if (rr & RR_CTS)
343 			val |= TIOCM_CTS;
344 		if (rr & RR_DCD)
345 			val |= TIOCM_CD;
346 		goto done;
347 	}
348 	sc->sc_wr[WR5] = wr5;
349 	setsioreg(sc->sc_ctl, WR5, wr5);
350 	val = 0;
351   done:
352 	splx(s);
353 	return val;
354 }
355 
356 /*--------------------  cdevsw[] interface --------------------*/
357 
358 int
359 sioopen(dev, flag, mode, l)
360 	dev_t dev;
361 	int flag, mode;
362 	struct lwp *l;
363 {
364 	struct siotty_softc *sc;
365 	struct tty *tp;
366 	int error;
367 
368 	if ((sc = siotty_cd.cd_devs[minor(dev)]) == NULL)
369 		return ENXIO;
370 	if ((tp = sc->sc_tty) == NULL) {
371 		tp = sc->sc_tty = ttymalloc();
372 		tty_attach(tp);
373 	}
374 
375 	tp->t_oproc = siostart;
376 	tp->t_param = sioparam;
377 	tp->t_hwiflow = NULL /* XXX siohwiflow XXX */;
378 	tp->t_dev = dev;
379 
380 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
381 		return (EBUSY);
382 
383 	if ((tp->t_state & TS_ISOPEN) == 0 && tp->t_wopen == 0) {
384 		struct termios t;
385 
386 		t.c_ispeed = t.c_ospeed = TTYDEF_SPEED;
387 		t.c_cflag = TTYDEF_CFLAG;
388 		tp->t_ospeed = 0; /* force register update */
389 		(void)sioparam(tp, &t);
390 		tp->t_iflag = TTYDEF_IFLAG;
391 		tp->t_oflag = TTYDEF_OFLAG;
392 		tp->t_lflag = TTYDEF_LFLAG;
393 		ttychars(tp);
394 		ttsetwater(tp);
395 		/* raise RTS and DTR here; but, DTR lead is not wired */
396 		/* then check DCD condition; but, DCD lead is not wired */
397 		tp->t_state |= TS_CARR_ON; /* assume detected all the time */
398 #if 0
399 		if ((sc->sc_flags & TIOCFLAG_SOFTCAR)
400 		    || (tp->t_cflag & MDMBUF)
401 		    || (getsiocsr(sc->sc_ctl) & RR_DCD))
402 			tp->t_state |= TS_CARR_ON;
403 		else
404 			tp->t_state &= ~TS_CARR_ON;
405 #endif
406 	}
407 
408 	error = ttyopen(tp, 0, (flag & O_NONBLOCK));
409 	if (error > 0)
410 		return error;
411 	return (*tp->t_linesw->l_open)(dev, tp);
412 }
413 
414 int
415 sioclose(dev, flag, mode, l)
416 	dev_t dev;
417 	int flag, mode;
418 	struct lwp *l;
419 {
420 	struct siotty_softc *sc = siotty_cd.cd_devs[minor(dev)];
421 	struct tty *tp = sc->sc_tty;
422 	int s;
423 
424 	(*tp->t_linesw->l_close)(tp, flag);
425 
426 	s = spltty();
427 	siomctl(sc, TIOCM_BREAK, DMBIC);
428 #if 0 /* because unable to feed DTR signal */
429 	if ((tp->t_cflag & HUPCL)
430 	    || tp->t_wopen || (tp->t_state & TS_ISOPEN) == 0) {
431 		siomctl(sc, TIOCM_DTR, DMBIC);
432 		/* Yield CPU time to others for 1 second, then ... */
433 		siomctl(sc, TIOCM_DTR, DMBIS);
434 	}
435 #endif
436 	splx(s);
437 	return ttyclose(tp);
438 }
439 
440 int
441 sioread(dev, uio, flag)
442 	dev_t dev;
443 	struct uio *uio;
444 	int flag;
445 {
446 	struct siotty_softc *sc = siotty_cd.cd_devs[minor(dev)];
447 	struct tty *tp = sc->sc_tty;
448 
449 	return (*tp->t_linesw->l_read)(tp, uio, flag);
450 }
451 
452 int
453 siowrite(dev, uio, flag)
454 	dev_t dev;
455 	struct uio *uio;
456 	int flag;
457 {
458 	struct siotty_softc *sc = siotty_cd.cd_devs[minor(dev)];
459 	struct tty *tp = sc->sc_tty;
460 
461 	return (*tp->t_linesw->l_write)(tp, uio, flag);
462 }
463 
464 int
465 siopoll(dev, events, l)
466 	dev_t dev;
467 	int events;
468 	struct lwp *l;
469 {
470 	struct siotty_softc *sc = siotty_cd.cd_devs[minor(dev)];
471 	struct tty *tp = sc->sc_tty;
472 
473 	return ((*tp->t_linesw->l_poll)(tp, events, l));
474 }
475 
476 int
477 sioioctl(dev, cmd, data, flag, l)
478 	dev_t dev;
479 	u_long cmd;
480 	void *data;
481 	int flag;
482 	struct lwp *l;
483 {
484 	struct siotty_softc *sc = siotty_cd.cd_devs[minor(dev)];
485 	struct tty *tp = sc->sc_tty;
486 	int error;
487 
488 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
489 	if (error != EPASSTHROUGH)
490 		return error;
491 
492 	error = ttioctl(tp, cmd, data, flag, l);
493 	if (error != EPASSTHROUGH)
494 		return error;
495 
496 	/* the last resort for TIOC ioctl tranversing */
497 	switch (cmd) {
498 	case TIOCSBRK: /* Set the hardware into BREAK condition */
499 		siomctl(sc, TIOCM_BREAK, DMBIS);
500 		break;
501 	case TIOCCBRK: /* Clear the hardware BREAK condition */
502 		siomctl(sc, TIOCM_BREAK, DMBIC);
503 		break;
504 	case TIOCSDTR: /* Assert DTR signal */
505 		siomctl(sc, TIOCM_DTR|TIOCM_RTS, DMBIS);
506 		break;
507 	case TIOCCDTR: /* Clear DTR signal */
508 		siomctl(sc, TIOCM_DTR|TIOCM_RTS, DMBIC);
509 		break;
510 	case TIOCMSET: /* Set modem state replacing current one */
511 		siomctl(sc, *(int *)data, DMSET);
512 		break;
513 	case TIOCMGET: /* Return current modem state */
514 		*(int *)data = siomctl(sc, 0, DMGET);
515 		break;
516 	case TIOCMBIS: /* Set individual bits of modem state */
517 		siomctl(sc, *(int *)data, DMBIS);
518 		break;
519 	case TIOCMBIC: /* Clear individual bits of modem state */
520 		siomctl(sc, *(int *)data, DMBIC);
521 		break;
522 	case TIOCSFLAGS: /* Instruct how serial port behaves */
523 		sc->sc_flags = *(int *)data;
524 		break;
525 	case TIOCGFLAGS: /* Return current serial port state */
526 		*(int *)data = sc->sc_flags;
527 		break;
528 	default:
529 		return EPASSTHROUGH;
530 	}
531 	return 0;
532 }
533 
534 /* ARSGUSED */
535 struct tty *
536 siotty(dev)
537 	dev_t dev;
538 {
539 	struct siotty_softc *sc = siotty_cd.cd_devs[minor(dev)];
540 
541 	return sc->sc_tty;
542 }
543 
544 /*--------------------  miscelleneous routine --------------------*/
545 
546 /* EXPORT */ void
547 setsioreg(sio, regno, val)
548 	struct sioreg *sio;
549 	int regno, val;
550 {
551 	if (regno != 0)
552 		sio->sio_cmd = regno;	/* DELAY(); */
553 	sio->sio_cmd = val;		/* DELAY(); */
554 }
555 
556 /* EXPORT */ int
557 getsiocsr(sio)
558 	struct sioreg *sio;
559 {
560 	int val;
561 
562 	val = sio->sio_stat << 8;	/* DELAY(); */
563 	sio->sio_cmd = 1;		/* DELAY(); */
564 	val |= sio->sio_stat;		/* DELAY(); */
565 	return val;
566 }
567 
568 /*---------------------  console interface ----------------------*/
569 
570 void syscnattach __P((int));
571 int  syscngetc __P((dev_t));
572 void syscnputc __P((dev_t, int));
573 
574 struct consdev syscons = {
575 	NULL,
576 	NULL,
577 	syscngetc,
578 	syscnputc,
579 	nullcnpollc,
580 	NULL,
581 	NULL,
582 	NULL,
583 	NODEV,
584 	CN_REMOTE,
585 };
586 
587 /* EXPORT */ void
588 syscnattach(channel)
589 	int channel;
590 {
591 /*
592  * Channel A is immediately initialized with 9600N1 right after cold
593  * boot/reset/poweron.  ROM monitor emits one line message on CH.A.
594  */
595 	struct sioreg *sio;
596 	sio = (struct sioreg *)0x51000000 + channel;
597 
598 	syscons.cn_dev = makedev(cdevsw_lookup_major(&siotty_cdevsw),
599 				 channel);
600 	cn_tab = &syscons;
601 
602 	setsioreg(sio, WR0, WR0_CHANRST);
603 	setsioreg(sio, WR2A, WR2_VEC86 | WR2_INTR_1);
604 	setsioreg(sio, WR2B, 0);
605 	setsioreg(sio, WR0, ch0_regs[WR0]);
606 	setsioreg(sio, WR4, ch0_regs[WR4]);
607 	setsioreg(sio, WR3, ch0_regs[WR3]);
608 	setsioreg(sio, WR5, ch0_regs[WR5]);
609 	setsioreg(sio, WR0, ch0_regs[WR0]);
610 }
611 
612 /* EXPORT */ int
613 syscngetc(dev)
614 	dev_t dev;
615 {
616 	struct sioreg *sio;
617 	int s, c;
618 
619 	sio = (struct sioreg *)0x51000000 + ((int)dev & 0x1);
620 	s = splhigh();
621 	while ((getsiocsr(sio) & RR_RXRDY) == 0)
622 		;
623 	c = sio->sio_data;
624 	splx(s);
625 
626 	return c;
627 }
628 
629 /* EXPORT */ void
630 syscnputc(dev, c)
631 	dev_t dev;
632 	int c;
633 {
634 	struct sioreg *sio;
635 	int s;
636 
637 	sio = (struct sioreg *)0x51000000 + ((int)dev & 0x1);
638 	s = splhigh();
639 	while ((getsiocsr(sio) & RR_TXRDY) == 0)
640 		;
641 	sio->sio_cmd = WR0_RSTPEND;
642 	sio->sio_data = c;
643 	splx(s);
644 }
645