xref: /netbsd/sys/arch/mips/sibyte/dev/sbscn.c (revision bf9ec67e)
1 /* $NetBSD: sbscn.c,v 1.1 2002/03/05 23:46:43 simonb Exp $ */
2 
3 /*
4  * Copyright 2000, 2001
5  * Broadcom Corporation. All rights reserved.
6  *
7  * This software is furnished under license and may be used and copied only
8  * in accordance with the following terms and conditions.  Subject to these
9  * conditions, you may download, copy, install, use, modify and distribute
10  * modified or unmodified copies of this software in source and/or binary
11  * form. No title or ownership is transferred hereby.
12  *
13  * 1) Any source code used, modified or distributed must reproduce and
14  *    retain this copyright notice and list of conditions as they appear in
15  *    the source file.
16  *
17  * 2) No right is granted to use any trade name, trademark, or logo of
18  *    Broadcom Corporation. Neither the "Broadcom Corporation" name nor any
19  *    trademark or logo of Broadcom Corporation may be used to endorse or
20  *    promote products derived from this software without the prior written
21  *    permission of Broadcom Corporation.
22  *
23  * 3) THIS SOFTWARE IS PROVIDED "AS-IS" AND ANY EXPRESS OR IMPLIED
24  *    WARRANTIES, INCLUDING BUT NOT LIMITED TO, ANY IMPLIED WARRANTIES OF
25  *    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
26  *    NON-INFRINGEMENT ARE DISCLAIMED. IN NO EVENT SHALL BROADCOM BE LIABLE
27  *    FOR ANY DAMAGES WHATSOEVER, AND IN PARTICULAR, BROADCOM SHALL NOT BE
28  *    LIABLE FOR DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  *    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  *    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
31  *    BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
32  *    WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
33  *    OR OTHERWISE), EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 #define	SBSCN_DEBUG
37 
38 /* from: $NetBSD: com.c,v 1.172 2000/05/03 19:19:04 thorpej Exp */
39 
40 /*-
41  * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
42  * All rights reserved.
43  *
44  * This code is derived from software contributed to The NetBSD Foundation
45  * by Charles M. Hannum.
46  *
47  * Redistribution and use in source and binary forms, with or without
48  * modification, are permitted provided that the following conditions
49  * are met:
50  * 1. Redistributions of source code must retain the above copyright
51  *    notice, this list of conditions and the following disclaimer.
52  * 2. Redistributions in binary form must reproduce the above copyright
53  *    notice, this list of conditions and the following disclaimer in the
54  *    documentation and/or other materials provided with the distribution.
55  * 3. All advertising materials mentioning features or use of this software
56  *    must display the following acknowledgement:
57  *        This product includes software developed by the NetBSD
58  *        Foundation, Inc. and its contributors.
59  * 4. 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  * Copyright (c) 1991 The Regents of the University of California.
78  * All rights reserved.
79  *
80  * Redistribution and use in source and binary forms, with or without
81  * modification, are permitted provided that the following conditions
82  * are met:
83  * 1. Redistributions of source code must retain the above copyright
84  *    notice, this list of conditions and the following disclaimer.
85  * 2. Redistributions in binary form must reproduce the above copyright
86  *    notice, this list of conditions and the following disclaimer in the
87  *    documentation and/or other materials provided with the distribution.
88  * 3. All advertising materials mentioning features or use of this software
89  *    must display the following acknowledgement:
90  *	This product includes software developed by the University of
91  *	California, Berkeley and its contributors.
92  * 4. Neither the name of the University nor the names of its contributors
93  *    may be used to endorse or promote products derived from this software
94  *    without specific prior written permission.
95  *
96  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
97  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
98  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
99  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
100  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
101  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
102  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
103  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
104  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
105  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
106  * SUCH DAMAGE.
107  *
108  *	@(#)com.c	7.5 (Berkeley) 5/16/91
109  */
110 
111 /*
112  * `sbscn' driver, supports SiByte SB-1250 SOC DUART.
113  *
114  * This DUART is quite similar in programming model to the scn2681/68681
115  * DUARTs supported by the NetBSD/amiga `mfc' and NetBSD/pc532 `scn'
116  * driver, but substantial rework would have been necessary to make
117  * those drivers sane w.r.t. bus_space (which would then have been
118  * required on NetBSD/sbmips very early on), and to accommodate the
119  * different register mappings.
120  *
121  * So, another driver.  Eventually there should be One True Driver,
122  * but we're not here to save the world.
123  */
124 
125 #include "opt_ddb.h"
126 
127 #include "rnd.h"
128 #if NRND > 0 && defined(RND_SBSCN)
129 #include <sys/rnd.h>
130 #endif
131 
132 #include <sys/param.h>
133 #include <sys/systm.h>
134 #include <sys/ioctl.h>
135 #include <sys/select.h>
136 #include <sys/tty.h>
137 #include <sys/proc.h>
138 #include <sys/user.h>
139 #include <sys/conf.h>
140 #include <sys/file.h>
141 #include <sys/uio.h>
142 #include <sys/kernel.h>
143 #include <sys/syslog.h>
144 #include <sys/types.h>
145 #include <sys/device.h>
146 #include <sys/malloc.h>
147 #include <sys/vnode.h>
148 
149 #include <mips/sibyte/dev/sbobiovar.h>
150 #if 0
151 #include <mips/sibyte/dev/sbscnreg.h>
152 #endif
153 #include <mips/sibyte/dev/sbscnvar.h>
154 #include <dev/cons.h>
155 #include <machine/locore.h>
156 
157 void	sbscn_attach_channel(struct sbscn_softc *sc, int chan, int intr);
158 #if defined(DDB) || defined(KGDB)
159 static void sbscn_enable_debugport(struct sbscn_channel *ch);
160 #endif
161 void	sbscn_config(struct sbscn_channel *ch);
162 void	sbscn_shutdown(struct sbscn_channel *ch);
163 int	sbscn_speed(long, long *);
164 static int cflag2modes(tcflag_t, u_char *, u_char *);
165 int	sbscn_param(struct tty *, struct termios *);
166 void	sbscn_start(struct tty *);
167 void	sbscnstop(struct tty *, int);
168 int	sbscn_hwiflow(struct tty *, int);
169 
170 void	sbscn_loadchannelregs(struct sbscn_channel *);
171 void	sbscn_dohwiflow(struct sbscn_channel *);
172 void	sbscn_break(struct sbscn_channel *, int);
173 void	sbscn_modem(struct sbscn_channel *, int);
174 void	tiocm_to_sbscn(struct sbscn_channel *, int, int);
175 int	sbscn_to_tiocm(struct sbscn_channel *);
176 void	sbscn_iflush(struct sbscn_channel *);
177 
178 int	sbscn_init(u_long addr, int chan, int rate, tcflag_t cflag);
179 int	sbscn_common_getc(u_long addr, int chan);
180 void	sbscn_common_putc(u_long addr, int chan, int c);
181 void	sbscn_intr(void *arg, uint32_t status, uint32_t pc);
182 
183 /* XXX: These belong elsewhere */
184 cdev_decl(sbscn);
185 
186 int	sbscn_cngetc(dev_t dev);
187 void	sbscn_cnputc(dev_t dev, int c);
188 void	sbscn_cnpollc(dev_t dev, int on);
189 
190 extern struct cfdriver sbscn_cd;
191 
192 #define	integrate	static inline
193 void 	sbscn_soft(void *);
194 integrate void sbscn_rxsoft(struct sbscn_channel *, struct tty *);
195 integrate void sbscn_txsoft(struct sbscn_channel *, struct tty *);
196 integrate void sbscn_stsoft(struct sbscn_channel *, struct tty *);
197 integrate void sbscn_schedrx(struct sbscn_channel *);
198 void	sbscn_diag(void *);
199 
200 /*
201  * Make this an option variable one can patch.
202  * But be warned:  this must be a power of 2!
203  */
204 u_int sbscn_rbuf_size = SBSCN_RING_SIZE;
205 
206 /* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
207 u_int sbscn_rbuf_hiwat = (SBSCN_RING_SIZE * 1) / 4;
208 u_int sbscn_rbuf_lowat = (SBSCN_RING_SIZE * 3) / 4;
209 
210 static int	sbscn_cons_present;
211 static int	sbscn_cons_attached;
212 static u_long	sbscn_cons_addr;
213 static int	sbscn_cons_chan;
214 static int	sbscn_cons_rate;
215 static tcflag_t	sbscn_cons_cflag;
216 
217 #ifdef KGDB
218 #include <sys/kgdb.h>
219 
220 static int	sbscn_kgdb_present;
221 static int	sbscn_kgdb_attached;
222 static u_long	sbscn_kgdb_addr;
223 static int	sbscn_kgdb_chan;
224 
225 int	sbscn_kgdb_getc(void *);
226 void	sbscn_kgdb_putc(void *, int);
227 #endif /* KGDB */
228 
229 static int	sbscn_match(struct device *, struct cfdata *, void *);
230 static void	sbscn_attach(struct device *, struct device *, void *);
231 
232 const struct cfattach sbscn_ca = {
233 	sizeof(struct sbscn_softc), sbscn_match, sbscn_attach,
234 };
235 
236 #define	READ_REG(rp)		(mips3_ld((uint64_t *)(rp)))
237 #define	WRITE_REG(rp, val)	(mips3_sd((uint64_t *)(rp), (val)))
238 
239 /*
240  * input and output signals are actually the _inverse_ of the bits in the
241  * input and output port registers!
242  */
243 #define	GET_INPUT_SIGNALS(ch) \
244     ((~READ_REG(MIPS_PHYS_TO_KSEG1((ch)->ch_sc->sc_addr + 0x280))) & (ch)->ch_i_mask)
245 #define	SET_OUTPUT_SIGNALS(ch, val) 					\
246     do {								\
247 	int sigs_to_set, sigs_to_clr;					\
248 									\
249 	sigs_to_set = (ch)->ch_o_mask & val;				\
250 	sigs_to_clr = (ch)->ch_o_mask & ~val;				\
251 									\
252 	/* set signals by clearing op bits, and vice versa */		\
253 	WRITE_REG(MIPS_PHYS_TO_KSEG1((ch)->ch_sc->sc_addr + 0x2c0),	\
254 	    sigs_to_set);						\
255 	WRITE_REG(MIPS_PHYS_TO_KSEG1((ch)->ch_sc->sc_addr + 0x2b0),	\
256 	    sigs_to_clr);						\
257     } while (0)
258 
259 static int
260 sbscn_match(struct device *parent, struct cfdata *match, void *aux)
261 {
262 	struct sbobio_attach_args *sap = aux;
263 
264 	if (sap->sa_locs.sa_type != SBOBIO_DEVTYPE_DUART)
265 		return (0);
266 
267 	return 1;
268 }
269 
270 static void
271 sbscn_attach(struct device *parent, struct device *self, void *aux)
272 {
273 	struct sbscn_softc *sc = (struct sbscn_softc *)self;
274 	struct sbobio_attach_args *sap = aux;
275 	int i;
276 
277 	sc->sc_addr = sap->sa_base + sap->sa_locs.sa_offset;
278 
279 	printf("\n");
280 	for (i = 0; i < 2; i++)
281 		sbscn_attach_channel(sc, i, sap->sa_locs.sa_intr[i]);
282 
283 	/* init duart_opcr */
284 	WRITE_REG(MIPS_PHYS_TO_KSEG1(sc->sc_addr + 0x270), 0);
285 	/* init duart_aux_ctrl */
286 	WRITE_REG(MIPS_PHYS_TO_KSEG1(sc->sc_addr + 0x210), 0x0f); /* XXX */
287 }
288 
289 void
290 sbscn_attach_channel(struct sbscn_softc *sc, int chan, int intr)
291 {
292 	struct sbscn_channel *ch = &sc->sc_channels[chan];
293 	u_long chan_addr;
294 	struct tty *tp;
295 
296 	ch->ch_sc = sc;
297 	ch->ch_num = chan;
298 
299 	chan_addr = sc->sc_addr + (0x100 * chan);
300 	ch->ch_base = (void *)MIPS_PHYS_TO_KSEG1(chan_addr);
301 	ch->ch_isr_base =
302 	    (void *)MIPS_PHYS_TO_KSEG1(sc->sc_addr + 0x220 + (0x20 * chan));
303 	ch->ch_imr_base =
304 	    (void *)MIPS_PHYS_TO_KSEG1(sc->sc_addr + 0x230 + (0x20 * chan));
305 #ifdef XXXCGDnotyet
306 	ch->ch_inchg_base =
307 	    (void *)MIPS_PHYS_TO_KSEG1(sc->sc_addr + 0x2d0 + (0x10 * chan));
308 #endif
309 
310 	ch->ch_i_dcd = ch->ch_i_dcd_pin = 0 /* XXXCGD */;
311 	ch->ch_i_cts = ch->ch_i_cts_pin = 0 /* XXXCGD */;
312 	ch->ch_i_dsr = ch->ch_i_dsr_pin = 0 /* XXXCGD */;
313 	ch->ch_i_ri = ch->ch_i_ri_pin = 0 /* XXXCGD */;
314 	ch->ch_i_mask =
315 	    ch->ch_i_dcd | ch->ch_i_cts | ch->ch_i_dsr | ch->ch_i_ri;
316 	ch->ch_o_dtr = ch->ch_o_dtr_pin = 0 /* XXXCGD */;
317 	ch->ch_o_rts = ch->ch_o_rts_pin = 0 /* XXXCGD */;
318 	ch->ch_o_mask = ch->ch_o_dtr | ch->ch_o_rts;
319 
320 	ch->ch_intrhand = cpu_intr_establish(intr, IPL_SERIAL, sbscn_intr, ch);
321 	callout_init(&ch->ch_diag_callout);
322 
323 	/* Disable interrupts before configuring the device. */
324 	ch->ch_imr = 0;
325 	WRITE_REG(ch->ch_imr_base, ch->ch_imr);
326 
327 	if (sbscn_cons_present &&
328 	    sbscn_cons_addr == chan_addr && sbscn_cons_chan == chan) {
329 		sbscn_cons_attached = 1;
330 
331 		/* Make sure the console is always "hardwired". */
332 		delay(1000);			/* wait for output to finish */
333 		SET(ch->ch_hwflags, SBSCN_HW_CONSOLE);
334 		SET(ch->ch_swflags, TIOCFLAG_SOFTCAR);
335 	}
336 
337 	tp = ttymalloc();
338 	tp->t_oproc = sbscn_start;
339 	tp->t_param = sbscn_param;
340 	tp->t_hwiflow = sbscn_hwiflow;
341 
342 	ch->ch_tty = tp;
343 	ch->ch_rbuf = malloc(sbscn_rbuf_size << 1, M_DEVBUF, M_NOWAIT);
344 	if (ch->ch_rbuf == NULL) {
345 		printf("%s: channel %d: unable to allocate ring buffer\n",
346 		    sc->sc_dev.dv_xname, chan);
347 		return;
348 	}
349 	ch->ch_ebuf = ch->ch_rbuf + (sbscn_rbuf_size << 1);
350 
351 	tty_attach(tp);
352 
353 	if (ISSET(ch->ch_hwflags, SBSCN_HW_CONSOLE)) {
354 		int maj;
355 
356 		/* locate the major number */
357 		for (maj = 0; maj < nchrdev; maj++)
358 			if (cdevsw[maj].d_open == sbscnopen)
359 				break;
360 
361 		cn_tab->cn_dev = makedev(maj, (sc->sc_dev.dv_unit << 1) + chan);
362 
363 		printf("%s: channel %d: console\n", sc->sc_dev.dv_xname, chan);
364 	}
365 
366 #ifdef KGDB
367 	/*
368 	 * Allow kgdb to "take over" this port.  If this is
369 	 * the kgdb device, it has exclusive use.
370 	 */
371 	if (sbscn_kgdb_present &&
372 	    sbscn_kgdb_addr == chan_addr && sbscn_kgdb_chan == chan) {
373 		sbscn_kgdb_attached = 1;
374 
375 		SET(sc->sc_hwflags, SBSCN_HW_KGDB);
376 		printf("%s: channel %d: kgdb\n", sc->sc_dev.dv_xname, chan);
377 	}
378 #endif
379 
380 	ch->ch_si = softintr_establish(IPL_SOFTSERIAL, sbscn_soft, ch);
381 
382 #if NRND > 0 && defined(RND_SBSCN)
383 	rnd_attach_source(&ch->ch_rnd_source, sc->sc_dev.dv_xname,
384 			  RND_TYPE_TTY, 0);
385 #endif
386 
387 	sbscn_config(ch);
388 
389 	SET(ch->ch_hwflags, SBSCN_HW_DEV_OK);
390 }
391 
392 int
393 sbscn_speed(long speed, long *brcp)
394 {
395 #define	divrnd(n, q)	(((n)*2/(q)+1)/2)	/* divide and round off */
396 
397 	int x, err;
398 	int frequency = 100000000;
399 
400 	*brcp = divrnd(frequency / 20, speed) - 1;
401 
402 	if (speed <= 0)
403 		return (-1);
404 	x = divrnd(frequency / 20, speed);
405 	if (x <= 0)
406 		return (-1);
407 	err = divrnd(((quad_t)frequency) * 1000 / 20, speed * x) - 1000;
408 	if (err < 0)
409 		err = -err;
410 	if (err > SBSCN_TOLERANCE)
411 		return (-1);
412 	*brcp = x - 1;
413 	return (0);
414 
415 #undef	divrnd
416 }
417 
418 #ifdef SBSCN_DEBUG
419 void	sbscn_status(struct sbscn_channel *, char *);
420 
421 int	sbscn_debug = 0 /* XXXCGD */;
422 
423 void
424 sbscn_status(struct sbscn_channel *ch, char *str)
425 {
426 	struct sbscn_softc *sc = ch->ch_sc;
427 	struct tty *tp = ch->ch_tty;
428 
429 	printf("%s: chan %d: %s %sclocal  %sdcd %sts_carr_on %sdtr %stx_stopped\n",
430 	    sc->sc_dev.dv_xname, ch->ch_num, str,
431 	    ISSET(tp->t_cflag, CLOCAL) ? "+" : "-",
432 	    ISSET(ch->ch_iports, ch->ch_i_dcd) ? "+" : "-",
433 	    ISSET(tp->t_state, TS_CARR_ON) ? "+" : "-",
434 	    ISSET(ch->ch_oports, ch->ch_o_dtr) ? "+" : "-",
435 	    ch->ch_tx_stopped ? "+" : "-");
436 
437 	printf("%s: chan %d: %s %scrtscts %scts %sts_ttstop  %srts %xrx_flags\n",
438 	    sc->sc_dev.dv_xname, ch->ch_num, str,
439 	    ISSET(tp->t_cflag, CRTSCTS) ? "+" : "-",
440 	    ISSET(ch->ch_iports, ch->ch_i_cts) ? "+" : "-",
441 	    ISSET(tp->t_state, TS_TTSTOP) ? "+" : "-",
442 	    ISSET(ch->ch_oports, ch->ch_o_rts) ? "+" : "-",
443 	    ch->ch_rx_flags);
444 }
445 #endif
446 
447 #if defined(DDB) || defined(KGDB)
448 static void
449 sbscn_enable_debugport(struct sbscn_channel *ch)
450 {
451 	int s;
452 
453 	/* Turn on line break interrupt, set carrier. */
454 	s = splserial();
455 
456 #if 0	/* DO NOT turn on break interrupt at this time. */
457 	ch->ch_imr = 0x04;
458 #else
459 	ch->ch_imr = 0x00;
460 #endif
461 	WRITE_REG(ch->ch_imr_base, ch->ch_imr);
462 	SET(ch->ch_oports, ch->ch_o_dtr | ch->ch_o_rts);
463 	SET_OUTPUT_SIGNALS(ch, ch->ch_oports);
464 
465 	splx(s);
466 }
467 #endif
468 
469 void
470 sbscn_config(struct sbscn_channel *ch)
471 {
472 
473 	/* Disable interrupts before configuring the device. */
474 	ch->ch_imr = 0x00;
475 	WRITE_REG(ch->ch_imr_base, ch->ch_imr);
476 
477 #ifdef DDB
478 	if (ISSET(ch->ch_hwflags, SBSCN_HW_CONSOLE))
479 		sbscn_enable_debugport(ch);
480 #endif
481 
482 #ifdef KGDB
483 	/*
484 	 * Allow kgdb to "take over" this port.  If this is
485 	 * the kgdb device, it has exclusive use.
486 	 */
487 	if (ISSET(ch->ch_hwflags, SBSCN_HW_KGDB))
488 		sbscn_enable_debugport(ch);
489 #endif
490 }
491 
492 void
493 sbscn_shutdown(struct sbscn_channel *ch)
494 {
495 	struct tty *tp = ch->ch_tty;
496 	int s;
497 
498 	s = splserial();
499 
500 	/* If we were asserting flow control, then deassert it. */
501 	SET(ch->ch_rx_flags, RX_IBUF_BLOCKED);
502 	sbscn_dohwiflow(ch);
503 
504 	/* Clear any break condition set with TIOCSBRK. */
505 	sbscn_break(ch, 0);
506 
507 	/*
508 	 * Hang up if necessary.  Wait a bit, so the other side has time to
509 	 * notice even if we immediately open the port again.
510 	 */
511 	if (ISSET(tp->t_cflag, HUPCL)) {
512 		sbscn_modem(ch, 0);
513 		(void) tsleep(ch, TTIPRI, ttclos, hz);
514 	}
515 
516 	/* Turn off interrupts. */
517 #ifdef DDB
518 	if (ISSET(ch->ch_hwflags, SBSCN_HW_CONSOLE))
519 #if 0	/* DO NOT turn on break interrupt at this time. */
520 		ch->ch_imr = 0x04; /* interrupt on break */
521 #else
522 		ch->ch_imr = 0x00;
523 #endif
524 	else
525 #endif
526 		ch->ch_imr = 0;
527 	WRITE_REG(ch->ch_imr_base, ch->ch_imr);
528 
529 	splx(s);
530 }
531 
532 int
533 sbscnopen(dev_t dev, int flag, int mode, struct proc *p)
534 {
535 	int unit = SBSCN_UNIT(dev);
536 	int chan = SBSCN_CHAN(dev);
537 	struct sbscn_softc *sc;
538 	struct sbscn_channel *ch;
539 	struct tty *tp;
540 	int s, s2;
541 	int error;
542 
543 	if (unit >= sbscn_cd.cd_ndevs)
544 		return (ENXIO);
545 	sc = sbscn_cd.cd_devs[unit];
546 	if (sc == 0)
547 		return (ENXIO);
548 	ch = &sc->sc_channels[chan];
549 	if (!ISSET(ch->ch_hwflags, SBSCN_HW_DEV_OK) || ch->ch_rbuf == NULL)
550 		return (ENXIO);
551 
552 #ifdef KGDB
553 	/*
554 	 * If this is the kgdb port, no other use is permitted.
555 	 */
556 	if (ISSET(ch->ch_hwflags, SBSCN_HW_KGDB))
557 		return (EBUSY);
558 #endif
559 
560 	tp = ch->ch_tty;
561 
562 	if (ISSET(tp->t_state, TS_ISOPEN) &&
563 	    ISSET(tp->t_state, TS_XCLUDE) &&
564 	    p->p_ucred->cr_uid != 0)
565 		return (EBUSY);
566 
567 	s = spltty();
568 
569 	/*
570 	 * Do the following iff this is a first open.
571 	 */
572 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
573 		struct termios t;
574 
575 		tp->t_dev = dev;
576 
577 		s2 = splserial();
578 
579 		/* Turn on receive, break, and status change interrupts. */
580 #if 0	/* DO NOT turn on break or status change interrupt at this time. */
581 		ch->ch_imr = 0xe;
582 #else
583 		ch->ch_imr = 0x2;
584 #endif
585 		WRITE_REG(ch->ch_imr_base, ch->ch_imr);
586 
587 		/* Fetch the current modem control status, needed later. */
588 		ch->ch_iports = GET_INPUT_SIGNALS(ch);
589 		ch->ch_iports_delta = 0;
590 		splx(s2);
591 
592 		/*
593 		 * Initialize the termios status to the defaults.  Add in the
594 		 * sticky bits from TIOCSFLAGS.
595 		 */
596 		t.c_ispeed = 0;
597 		if (ISSET(ch->ch_hwflags, SBSCN_HW_CONSOLE)) {
598 			t.c_ospeed = sbscn_cons_rate;
599 			t.c_cflag = sbscn_cons_cflag;
600 		} else {
601 			t.c_ospeed = TTYDEF_SPEED;
602 			t.c_cflag = TTYDEF_CFLAG;
603 		}
604 		if (ISSET(ch->ch_swflags, TIOCFLAG_CLOCAL))
605 			SET(t.c_cflag, CLOCAL);
606 		if (ISSET(ch->ch_swflags, TIOCFLAG_CRTSCTS))
607 			SET(t.c_cflag, CRTSCTS);
608 		if (ISSET(ch->ch_swflags, TIOCFLAG_MDMBUF))
609 			SET(t.c_cflag, MDMBUF);
610 		/* Make sure sbscn_param() will do something. */
611 		tp->t_ospeed = 0;
612 		(void) sbscn_param(tp, &t);
613 		tp->t_iflag = TTYDEF_IFLAG;
614 		tp->t_oflag = TTYDEF_OFLAG;
615 		tp->t_lflag = TTYDEF_LFLAG;
616 		ttychars(tp);
617 		ttsetwater(tp);
618 
619 		s2 = splserial();
620 
621 		/*
622 		 * Turn on DTR.  We must always do this, even if carrier is not
623 		 * present, because otherwise we'd have to use TIOCSDTR
624 		 * immediately after setting CLOCAL, which applications do not
625 		 * expect.  We always assert DTR while the device is open
626 		 * unless explicitly requested to deassert it.
627 		 */
628 		sbscn_modem(ch, 1);
629 
630 		/* Clear the input ring, and unblock. */
631 		ch->ch_rbput = ch->ch_rbget = ch->ch_rbuf;
632 		ch->ch_rbavail = sbscn_rbuf_size;
633 		sbscn_iflush(ch);
634 		CLR(ch->ch_rx_flags, RX_ANY_BLOCK);
635 		sbscn_dohwiflow(ch);
636 
637 #ifdef SBSCN_DEBUG
638 		if (sbscn_debug)
639 			sbscn_status(ch, "sbscnopen  ");
640 #endif
641 
642 		splx(s2);
643 	}
644 
645 	splx(s);
646 
647 	error = ttyopen(tp, SBSCN_DIALOUT(dev), ISSET(flag, O_NONBLOCK));
648 	if (error)
649 		goto bad;
650 
651 	error = (*tp->t_linesw->l_open)(dev, tp);
652 	if (error)
653 		goto bad;
654 
655 	return (0);
656 
657 bad:
658 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
659 		/*
660 		 * We failed to open the device, and nobody else had it opened.
661 		 * Clean up the state as appropriate.
662 		 */
663 		sbscn_shutdown(ch);
664 	}
665 
666 	return (error);
667 }
668 
669 int
670 sbscnclose(dev_t dev, int flag, int mode, struct proc *p)
671 {
672 	struct sbscn_softc *sc = sbscn_cd.cd_devs[SBSCN_UNIT(dev)];
673 	struct sbscn_channel *ch = &sc->sc_channels[SBSCN_CHAN(dev)];
674 	struct tty *tp = ch->ch_tty;
675 
676 	/* XXX This is for cons.c. */
677 	if (!ISSET(tp->t_state, TS_ISOPEN))
678 		return (0);
679 
680 	(*tp->t_linesw->l_close)(tp, flag);
681 	ttyclose(tp);
682 
683 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
684 		/*
685 		 * Although we got a last close, the device may still be in
686 		 * use; e.g. if this was the dialout node, and there are still
687 		 * processes waiting for carrier on the non-dialout node.
688 		 */
689 		sbscn_shutdown(ch);
690 	}
691 
692 	return (0);
693 }
694 
695 int
696 sbscnread(dev_t dev, struct uio *uio, int flag)
697 {
698 	struct sbscn_softc *sc = sbscn_cd.cd_devs[SBSCN_UNIT(dev)];
699 	struct sbscn_channel *ch = &sc->sc_channels[SBSCN_CHAN(dev)];
700 	struct tty *tp = ch->ch_tty;
701 
702 	return ((*tp->t_linesw->l_read)(tp, uio, flag));
703 }
704 
705 int
706 sbscnwrite(dev_t dev, struct uio *uio, int flag)
707 {
708 	struct sbscn_softc *sc = sbscn_cd.cd_devs[SBSCN_UNIT(dev)];
709 	struct sbscn_channel *ch = &sc->sc_channels[SBSCN_CHAN(dev)];
710 	struct tty *tp = ch->ch_tty;
711 
712 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
713 }
714 
715 int
716 sbscnpoll(dev_t dev, int events, struct proc *p)
717 {
718 	struct sbscn_softc *sc = sbscn_cd.cd_devs[SBSCN_UNIT(dev)];
719 	struct sbscn_channel *ch = &sc->sc_channels[SBSCN_CHAN(dev)];
720 	struct tty *tp = ch->ch_tty;
721 
722 	return ((*tp->t_linesw->l_poll)(tp, events, p));
723 }
724 
725 struct tty *
726 sbscntty(dev_t dev)
727 {
728 	struct sbscn_softc *sc = sbscn_cd.cd_devs[SBSCN_UNIT(dev)];
729 	struct sbscn_channel *ch = &sc->sc_channels[SBSCN_CHAN(dev)];
730 	struct tty *tp = ch->ch_tty;
731 
732 	return (tp);
733 }
734 
735 int
736 sbscnioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
737 {
738 	struct sbscn_softc *sc = sbscn_cd.cd_devs[SBSCN_UNIT(dev)];
739 	struct sbscn_channel *ch = &sc->sc_channels[SBSCN_CHAN(dev)];
740 	struct tty *tp = ch->ch_tty;
741 	int error;
742 	int s;
743 
744 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, p);
745 	if (error >= 0)
746 		return (error);
747 
748 	error = ttioctl(tp, cmd, data, flag, p);
749 	if (error >= 0)
750 		return (error);
751 
752 	error = 0;
753 
754 	s = splserial();
755 
756 	switch (cmd) {
757 	case TIOCSBRK:
758 		sbscn_break(ch, 1);
759 		break;
760 
761 	case TIOCCBRK:
762 		sbscn_break(ch, 0);
763 		break;
764 
765 	case TIOCSDTR:
766 		sbscn_modem(ch, 1);
767 		break;
768 
769 	case TIOCCDTR:
770 		sbscn_modem(ch, 0);
771 		break;
772 
773 	case TIOCGFLAGS:
774 		*(int *)data = ch->ch_swflags;
775 		break;
776 
777 	case TIOCSFLAGS:
778 		error = suser(p->p_ucred, &p->p_acflag);
779 		if (error)
780 			break;
781 		ch->ch_swflags = *(int *)data;
782 		break;
783 
784 	case TIOCMSET:
785 	case TIOCMBIS:
786 	case TIOCMBIC:
787 		tiocm_to_sbscn(ch, cmd, *(int *)data);
788 		break;
789 
790 	case TIOCMGET:
791 		*(int *)data = sbscn_to_tiocm(ch);
792 		break;
793 
794 	default:
795 		error = ENOTTY;
796 		break;
797 	}
798 
799 	splx(s);
800 
801 #ifdef SBSCN_DEBUG
802 	if (sbscn_debug)
803 		sbscn_status(ch, "sbscn_ioctl ");
804 #endif
805 
806 	return (error);
807 }
808 
809 integrate void
810 sbscn_schedrx(struct sbscn_channel *ch)
811 {
812 
813 	ch->ch_rx_ready = 1;
814 
815 	/* Wake up the poller. */
816 	softintr_schedule(ch->ch_si);
817 }
818 
819 void
820 sbscn_break(struct sbscn_channel *ch, int onoff)
821 {
822 
823 /* XXXCGD delay break until not busy */
824 	if (onoff)
825 		WRITE_REG(ch->ch_base + 0x50, 0x60);
826 	else
827 		WRITE_REG(ch->ch_base + 0x50, 0x70);
828 
829 #if 0
830 	if (!ch->ch_heldchange) {
831 		if (ch->ch_tx_busy) {
832 			ch->ch_heldtbc = ch->ch_tbc;
833 			ch->ch_tbc = 0;
834 			ch->ch_heldchange = 1;
835 		} else
836 			sbscn_loadchannelregs(ch);
837 	}
838 #endif
839 }
840 
841 void
842 sbscn_modem(struct sbscn_channel *ch, int onoff)
843 {
844 
845 	if (ch->ch_o_dtr == 0)
846 		return;
847 
848 	if (onoff)
849 		SET(ch->ch_oports, ch->ch_o_dtr);
850 	else
851 		CLR(ch->ch_oports, ch->ch_o_dtr);
852 
853 	if (!ch->ch_heldchange) {
854 		if (ch->ch_tx_busy) {
855 			ch->ch_heldtbc = ch->ch_tbc;
856 			ch->ch_tbc = 0;
857 			ch->ch_heldchange = 1;
858 		} else
859 			sbscn_loadchannelregs(ch);
860 	}
861 }
862 
863 void
864 tiocm_to_sbscn(struct sbscn_channel *ch, int how, int ttybits)
865 {
866 	u_char bits;
867 
868 	bits = 0;
869 	if (ISSET(ttybits, TIOCM_DTR))
870 		SET(bits, ch->ch_o_dtr);
871 	if (ISSET(ttybits, TIOCM_RTS))
872 		SET(bits, ch->ch_o_rts);
873 
874 	switch (how) {
875 	case TIOCMBIC:
876 		CLR(ch->ch_oports, bits);
877 		break;
878 
879 	case TIOCMBIS:
880 		SET(ch->ch_oports, bits);
881 		break;
882 
883 	case TIOCMSET:
884 		ch->ch_oports = bits;
885 		break;
886 	}
887 
888 	if (!ch->ch_heldchange) {
889 		if (ch->ch_tx_busy) {
890 			ch->ch_heldtbc = ch->ch_tbc;
891 			ch->ch_tbc = 0;
892 			ch->ch_heldchange = 1;
893 		} else
894 			sbscn_loadchannelregs(ch);
895 	}
896 }
897 
898 int
899 sbscn_to_tiocm(struct sbscn_channel *ch)
900 {
901 	u_char hwbits;
902 	int ttybits = 0;
903 
904 	hwbits = ch->ch_oports;
905 	if (ISSET(hwbits, ch->ch_o_dtr))
906 		SET(ttybits, TIOCM_DTR);
907 	if (ISSET(hwbits, ch->ch_o_rts))
908 		SET(ttybits, TIOCM_RTS);
909 
910 	hwbits = ch->ch_iports;
911 	if (ISSET(hwbits, ch->ch_i_dcd))
912 		SET(ttybits, TIOCM_CD);
913 	if (ISSET(hwbits, ch->ch_i_cts))
914 		SET(ttybits, TIOCM_CTS);
915 	if (ISSET(hwbits, ch->ch_i_dsr))
916 		SET(ttybits, TIOCM_DSR);
917 	if (ISSET(hwbits, ch->ch_i_ri))
918 		SET(ttybits, TIOCM_RI);
919 
920 	if (ch->ch_imr != 0)
921 		SET(ttybits, TIOCM_LE);
922 
923 	return (ttybits);
924 }
925 
926 static int
927 cflag2modes(cflag, mode1p, mode2p)
928 	tcflag_t cflag;
929 	u_char *mode1p;
930 	u_char *mode2p;
931 {
932 	u_char mode1;
933 	u_char mode2;
934 	int err = 0;
935 
936 	mode1 = mode2 = 0;
937 
938 	switch (ISSET(cflag, CSIZE)) {
939 	case CS7:
940 		mode1 |= 2;			/* XXX */
941 		break;
942 	default:
943 		err = -1;
944 		/* FALLTHRU for sanity */
945 	case CS8:
946 		mode1 |= 3;			/* XXX */
947 		break;
948 	}
949 	if (!ISSET(cflag, PARENB))
950 		mode1 |= 2 << 3;
951 	else {
952 		mode1 |= 0 << 3;
953 		if (ISSET(cflag, PARODD))
954 			mode1 |= 1 << 2;
955 	}
956 
957 	if (ISSET(cflag, CSTOPB))
958 		mode2 |= 1 << 3;		/* two stop bits XXX not std */
959 
960 	if (ISSET(cflag, CRTSCTS)) {
961 		mode1 |= 1 << 7;
962 		mode2 |= 1 << 4;
963 	}
964 
965 	*mode1p = mode1;
966 	*mode2p = mode2;
967 	return (err);
968 }
969 
970 int
971 sbscn_param(struct tty *tp, struct termios *t)
972 {
973 	struct sbscn_softc *sc = sbscn_cd.cd_devs[SBSCN_UNIT(tp->t_dev)];
974 	struct sbscn_channel *ch = &sc->sc_channels[SBSCN_CHAN(tp->t_dev)];
975 	long brc;
976 	u_char mode1, mode2;
977 	int s;
978 
979 /* XXX reset to console parameters if console? */
980 #if 0
981 XXX disable, enable.
982 #endif
983 
984 	/* Check requested parameters. */
985 	if (sbscn_speed(t->c_ospeed, &brc) < 0)
986 		return (EINVAL);
987 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
988 		return (EINVAL);
989 
990 	/*
991 	 * For the console, always force CLOCAL and !HUPCL, so that the port
992 	 * is always active.
993 	 */
994 	if (ISSET(ch->ch_swflags, TIOCFLAG_SOFTCAR) ||
995 	    ISSET(ch->ch_hwflags, SBSCN_HW_CONSOLE)) {
996 		SET(t->c_cflag, CLOCAL);
997 		CLR(t->c_cflag, HUPCL);
998 	}
999 
1000 	/*
1001 	 * If there were no changes, don't do anything.  This avoids dropping
1002 	 * input and improves performance when all we did was frob things like
1003 	 * VMIN and VTIME.
1004 	 */
1005 	if (tp->t_ospeed == t->c_ospeed &&
1006 	    tp->t_cflag == t->c_cflag)
1007 		return (0);
1008 
1009 	if (cflag2modes(t->c_cflag, &mode1, &mode2) < 0)
1010 		return (EINVAL);
1011 
1012 	s = splserial();
1013 
1014 	ch->ch_mode1 = mode1;
1015 	ch->ch_mode2 = mode2;
1016 
1017 	/*
1018 	 * If we're not in a mode that assumes a connection is present, then
1019 	 * ignore carrier changes.
1020 	 */
1021 	if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
1022 		ch->ch_i_dcd = 0;
1023 	else
1024 		ch->ch_i_dcd = ch->ch_i_dcd_pin;
1025 	/*
1026 	 * Set the flow control pins depending on the current flow control
1027 	 * mode.
1028 	 */
1029 	if (ISSET(t->c_cflag, CRTSCTS)) {
1030 		ch->ch_o_dtr = ch->ch_o_dtr_pin;
1031 		ch->ch_o_rts = ch->ch_o_rts_pin;
1032 		ch->ch_i_cts = ch->ch_i_cts_pin;
1033 		/* hw controle enable bits in mod regs set by cflag2modes */
1034 	} else if (ISSET(t->c_cflag, MDMBUF)) {
1035 		/*
1036 		 * For DTR/DCD flow control, make sure we don't toggle DTR for
1037 		 * carrier detection.
1038 		 */
1039 		ch->ch_o_dtr = 0;
1040 		ch->ch_o_rts = ch->ch_o_dtr_pin;
1041 		ch->ch_i_cts = ch->ch_i_dcd_pin;
1042 	} else {
1043 		/*
1044 		 * If no flow control, then always set RTS.  This will make
1045 		 * the other side happy if it mistakenly thinks we're doing
1046 		 * RTS/CTS flow control.
1047 		 */
1048 		ch->ch_o_dtr = ch->ch_o_dtr_pin | ch->ch_o_rts_pin;
1049 		ch->ch_o_rts = 0;
1050 		ch->ch_i_cts = 0;
1051 		if (ISSET(ch->ch_oports, ch->ch_o_dtr_pin))
1052 			SET(ch->ch_oports, ch->ch_o_rts_pin);
1053 		else
1054 			CLR(ch->ch_oports, ch->ch_o_rts_pin);
1055 	}
1056 	/* XXX maybe mask the ports which generate intrs? */
1057 
1058 	ch->ch_brc = brc;
1059 
1060 	/* XXX maybe set fifo-full receive mode if RTSCTS and high speed? */
1061 
1062 	/* And copy to tty. */
1063 	tp->t_ispeed = 0;
1064 	tp->t_ospeed = t->c_ospeed;
1065 	tp->t_cflag = t->c_cflag;
1066 
1067 	if (!ch->ch_heldchange) {
1068 		if (ch->ch_tx_busy) {
1069 			ch->ch_heldtbc = ch->ch_tbc;
1070 			ch->ch_tbc = 0;
1071 			ch->ch_heldchange = 1;
1072 		} else
1073 			sbscn_loadchannelregs(ch);
1074 	}
1075 
1076 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1077 		/* Disable the high water mark. */
1078 		ch->ch_r_hiwat = 0;
1079 		ch->ch_r_lowat = 0;
1080 		if (ISSET(ch->ch_rx_flags, RX_TTY_OVERFLOWED)) {
1081 			CLR(ch->ch_rx_flags, RX_TTY_OVERFLOWED);
1082 			sbscn_schedrx(ch);
1083 		}
1084 		if (ISSET(ch->ch_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
1085 			CLR(ch->ch_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
1086 			sbscn_dohwiflow(ch);
1087 		}
1088 	} else {
1089 		ch->ch_r_hiwat = sbscn_rbuf_hiwat;
1090 		ch->ch_r_lowat = sbscn_rbuf_lowat;
1091 	}
1092 
1093 	splx(s);
1094 
1095 	/*
1096 	 * Update the tty layer's idea of the carrier bit, in case we changed
1097 	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
1098 	 * explicit request.
1099 	 */
1100 	(void) (*tp->t_linesw->l_modem)(tp,
1101 	    ISSET(ch->ch_iports, ch->ch_i_dcd));
1102 
1103 #ifdef SBSCN_DEBUG
1104 	if (sbscn_debug)
1105 		sbscn_status(ch, "sbscnparam ");
1106 #endif
1107 
1108 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1109 		if (ch->ch_tx_stopped) {
1110 			ch->ch_tx_stopped = 0;
1111 			sbscn_start(tp);
1112 		}
1113 	}
1114 
1115 	return (0);
1116 }
1117 
1118 void
1119 sbscn_iflush(struct sbscn_channel *ch)
1120 {
1121 #ifdef DIAGNOSTIC
1122 	int reg;
1123 #endif
1124 	int timo;
1125 
1126 #ifdef DIAGNOSTIC
1127 	reg = 0xffff;
1128 #endif
1129 	timo = 50000;
1130 	/* flush any pending I/O */
1131 	while (ISSET(READ_REG(ch->ch_base + 0x20), 0x01)
1132 	    && --timo)
1133 #ifdef DIAGNOSTIC
1134 		reg =
1135 #else
1136 		    (void)
1137 #endif
1138 		    READ_REG(ch->ch_base + 0x60);
1139 #ifdef DIAGNOSTIC
1140 	if (!timo)
1141 		printf("%s: sbscn_iflush timeout %02x\n",
1142 		    ch->ch_sc->sc_dev.dv_xname, reg & 0xff);
1143 #endif
1144 }
1145 
1146 void
1147 sbscn_loadchannelregs(struct sbscn_channel *ch)
1148 {
1149 
1150 	/* XXXXX necessary? */
1151 	sbscn_iflush(ch);
1152 
1153 	WRITE_REG(ch->ch_imr_base, 0);
1154 
1155 // XXX disable?
1156 	WRITE_REG(ch->ch_base + 0x00, ch->ch_mode1);
1157 	WRITE_REG(ch->ch_base + 0x10, ch->ch_mode2);
1158 	WRITE_REG(ch->ch_base + 0x30, ch->ch_brc);
1159 
1160 	ch->ch_oports_active = ch->ch_oports;
1161 	SET_OUTPUT_SIGNALS(ch, ch->ch_oports_active);
1162 
1163 	WRITE_REG(ch->ch_imr_base, ch->ch_imr);
1164 }
1165 
1166 int
1167 sbscn_hwiflow(struct tty *tp, int block)
1168 {
1169 	struct sbscn_softc *sc = sbscn_cd.cd_devs[SBSCN_UNIT(tp->t_dev)];
1170 	struct sbscn_channel *ch = &sc->sc_channels[SBSCN_CHAN(tp->t_dev)];
1171 	int s;
1172 
1173 	if (ch->ch_o_rts == 0)
1174 		return (0);
1175 
1176 	s = splserial();
1177 	if (block) {
1178 		if (!ISSET(ch->ch_rx_flags, RX_TTY_BLOCKED)) {
1179 			SET(ch->ch_rx_flags, RX_TTY_BLOCKED);
1180 			sbscn_dohwiflow(ch);
1181 		}
1182 	} else {
1183 		if (ISSET(ch->ch_rx_flags, RX_TTY_OVERFLOWED)) {
1184 			CLR(ch->ch_rx_flags, RX_TTY_OVERFLOWED);
1185 			sbscn_schedrx(ch);
1186 		}
1187 		if (ISSET(ch->ch_rx_flags, RX_TTY_BLOCKED)) {
1188 			CLR(ch->ch_rx_flags, RX_TTY_BLOCKED);
1189 			sbscn_dohwiflow(ch);
1190 		}
1191 	}
1192 	splx(s);
1193 	return (1);
1194 }
1195 
1196 /*
1197  * (un)block input via hw flowcontrol
1198  */
1199 void
1200 sbscn_dohwiflow(struct sbscn_channel *ch)
1201 {
1202 
1203 	if (ch->ch_o_rts == 0)
1204 		return;
1205 
1206 	if (ISSET(ch->ch_rx_flags, RX_ANY_BLOCK)) {
1207 		CLR(ch->ch_oports, ch->ch_o_rts);
1208 		CLR(ch->ch_oports_active, ch->ch_o_rts);
1209 	} else {
1210 		SET(ch->ch_oports, ch->ch_o_rts);
1211 		SET(ch->ch_oports_active, ch->ch_o_rts);
1212 	}
1213 	SET_OUTPUT_SIGNALS(ch, ch->ch_oports_active);
1214 }
1215 
1216 void
1217 sbscn_start(struct tty *tp)
1218 {
1219 	struct sbscn_softc *sc = sbscn_cd.cd_devs[SBSCN_UNIT(tp->t_dev)];
1220 	struct sbscn_channel *ch = &sc->sc_channels[SBSCN_CHAN(tp->t_dev)];
1221 	int s;
1222 
1223 	s = spltty();
1224 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
1225 		goto out;
1226 	if (ch->ch_tx_stopped)
1227 		goto out;
1228 
1229 	if (tp->t_outq.c_cc <= tp->t_lowat) {
1230 		if (ISSET(tp->t_state, TS_ASLEEP)) {
1231 			CLR(tp->t_state, TS_ASLEEP);
1232 			wakeup(&tp->t_outq);
1233 		}
1234 		selwakeup(&tp->t_wsel);
1235 		if (tp->t_outq.c_cc == 0)
1236 			goto out;
1237 	}
1238 
1239 	/* Grab the first contiguous region of buffer space. */
1240 	{
1241 		u_char *tba;
1242 		int tbc;
1243 
1244 		tba = tp->t_outq.c_cf;
1245 		tbc = ndqb(&tp->t_outq, 0);
1246 
1247 		(void)splserial();
1248 
1249 		ch->ch_tba = tba;
1250 		ch->ch_tbc = tbc;
1251 	}
1252 
1253 	SET(tp->t_state, TS_BUSY);
1254 	ch->ch_tx_busy = 1;
1255 
1256 	/* Enable transmit completion interrupts if necessary. */
1257 	if (!ISSET(ch->ch_imr, 0x1)) {
1258 		SET(ch->ch_imr, 0x1);
1259 		WRITE_REG(ch->ch_imr_base, ch->ch_imr);
1260 	}
1261 
1262 	/* Output the first chunk of the contiguous buffer. */
1263 	{
1264 		u_char c;
1265 
1266 		while (ch->ch_tbc && READ_REG(ch->ch_base + 0x20) & 0x04) {
1267 			c = *ch->ch_tba++;
1268 			ch->ch_tbc--;
1269 			WRITE_REG(ch->ch_base + 0x70, c);
1270 		}
1271 	}
1272 out:
1273 	splx(s);
1274 	return;
1275 }
1276 
1277 /*
1278  * Stop output on a line.
1279  */
1280 void
1281 sbscnstop(struct tty *tp, int flag)
1282 {
1283 	struct sbscn_softc *sc = sbscn_cd.cd_devs[SBSCN_UNIT(tp->t_dev)];
1284 	struct sbscn_channel *ch = &sc->sc_channels[SBSCN_CHAN(tp->t_dev)];
1285 	int s;
1286 
1287 	s = splserial();
1288 	if (ISSET(tp->t_state, TS_BUSY)) {
1289 		/* Stop transmitting at the next chunk. */
1290 		ch->ch_tbc = 0;
1291 		ch->ch_heldtbc = 0;
1292 		if (!ISSET(tp->t_state, TS_TTSTOP))
1293 			SET(tp->t_state, TS_FLUSH);
1294 	}
1295 	splx(s);
1296 }
1297 
1298 void
1299 sbscn_diag(arg)
1300 	void *arg;
1301 {
1302 	struct sbscn_channel *ch = arg;
1303 	struct sbscn_softc *sc = ch->ch_sc;
1304 	int overflows, floods;
1305 	int s;
1306 
1307 	s = splserial();
1308 	overflows = ch->ch_overflows;
1309 	ch->ch_overflows = 0;
1310 	floods = ch->ch_floods;
1311 	ch->ch_floods = 0;
1312 	ch->ch_errors = 0;
1313 	splx(s);
1314 
1315 	log(LOG_WARNING, "%s: channel %d: %d fifo overflow%s, %d ibuf flood%s\n",
1316 	    sc->sc_dev.dv_xname, ch->ch_num,
1317 	    overflows, overflows == 1 ? "" : "s",
1318 	    floods, floods == 1 ? "" : "s");
1319 }
1320 
1321 integrate void
1322 sbscn_rxsoft(struct sbscn_channel *ch, struct tty *tp)
1323 {
1324 	int (*rint)(int c, struct tty *tp) = tp->t_linesw->l_rint;
1325 	u_char *get, *end;
1326 	u_int cc, scc;
1327 	u_char sr;
1328 	int code;
1329 	int s;
1330 
1331 	end = ch->ch_ebuf;
1332 	get = ch->ch_rbget;
1333 	scc = cc = sbscn_rbuf_size - ch->ch_rbavail;
1334 
1335 	if (cc == sbscn_rbuf_size) {
1336 		ch->ch_floods++;
1337 		if (ch->ch_errors++ == 0)
1338 			callout_reset(&ch->ch_diag_callout, 60 * hz,
1339 			    sbscn_diag, ch);
1340 	}
1341 
1342 	while (cc) {
1343 		code = get[0];
1344 		sr = get[1];
1345 		if (ISSET(sr, 0xf0)) {
1346 			if (ISSET(sr, 0x10)) {
1347 				ch->ch_overflows++;
1348 				if (ch->ch_errors++ == 0)
1349 					callout_reset(&ch->ch_diag_callout,
1350 					    60 * hz, sbscn_diag, ch);
1351 			}
1352 			if (ISSET(sr, 0xc0))
1353 				SET(code, TTY_FE);
1354 			if (ISSET(sr, 0x20))
1355 				SET(code, TTY_PE);
1356 		}
1357 		if ((*rint)(code, tp) == -1) {
1358 			/*
1359 			 * The line discipline's buffer is out of space.
1360 			 */
1361 			if (!ISSET(ch->ch_rx_flags, RX_TTY_BLOCKED)) {
1362 				/*
1363 				 * We're either not using flow control, or the
1364 				 * line discipline didn't tell us to block for
1365 				 * some reason.  Either way, we have no way to
1366 				 * know when there's more space available, so
1367 				 * just drop the rest of the data.
1368 				 */
1369 				get += cc << 1;
1370 				if (get >= end)
1371 					get -= sbscn_rbuf_size << 1;
1372 				cc = 0;
1373 			} else {
1374 				/*
1375 				 * Don't schedule any more receive processing
1376 				 * until the line discipline tells us there's
1377 				 * space available (through comhwiflow()).
1378 				 * Leave the rest of the data in the input
1379 				 * buffer.
1380 				 */
1381 				SET(ch->ch_rx_flags, RX_TTY_OVERFLOWED);
1382 			}
1383 			break;
1384 		}
1385 		get += 2;
1386 		if (get >= end)
1387 			get = ch->ch_rbuf;
1388 		cc--;
1389 	}
1390 
1391 	if (cc != scc) {
1392 		ch->ch_rbget = get;
1393 		s = splserial();
1394 		cc = ch->ch_rbavail += scc - cc;
1395 		/* Buffers should be ok again, release possible block. */
1396 		if (cc >= ch->ch_r_lowat) {
1397 			if (ISSET(ch->ch_rx_flags, RX_IBUF_OVERFLOWED)) {
1398 				CLR(ch->ch_rx_flags, RX_IBUF_OVERFLOWED);
1399 				SET(ch->ch_imr, 0x02);
1400 				WRITE_REG(ch->ch_imr_base, ch->ch_imr);
1401 			}
1402 			if (ISSET(ch->ch_rx_flags, RX_IBUF_BLOCKED)) {
1403 				CLR(ch->ch_rx_flags, RX_IBUF_BLOCKED);
1404 				sbscn_dohwiflow(ch);
1405 			}
1406 		}
1407 		splx(s);
1408 	}
1409 }
1410 
1411 integrate void
1412 sbscn_txsoft(struct sbscn_channel *ch, struct tty *tp)
1413 {
1414 
1415 	CLR(tp->t_state, TS_BUSY);
1416 	if (ISSET(tp->t_state, TS_FLUSH))
1417 		CLR(tp->t_state, TS_FLUSH);
1418 	else
1419 		ndflush(&tp->t_outq, (int)(ch->ch_tba - tp->t_outq.c_cf));
1420 	(*tp->t_linesw->l_start)(tp);
1421 }
1422 
1423 integrate void
1424 sbscn_stsoft(struct sbscn_channel *ch, struct tty *tp)
1425 {
1426 	u_char iports, delta;
1427 	int s;
1428 
1429 	s = splserial();
1430 	iports = ch->ch_iports;
1431 	delta = ch->ch_iports_delta;
1432 	ch->ch_iports_delta = 0;
1433 	splx(s);
1434 
1435 	if (ISSET(delta, ch->ch_i_dcd)) {
1436 		/*
1437 		 * Inform the tty layer that carrier detect changed.
1438 		 */
1439 		(void) (*tp->t_linesw->l_modem)(tp,
1440 		    ISSET(iports, ch->ch_i_dcd));
1441 	}
1442 
1443 	if (ISSET(delta, ch->ch_i_cts)) {
1444 		/* Block or unblock output according to flow control. */
1445 		if (ISSET(iports, ch->ch_i_cts)) {
1446 			ch->ch_tx_stopped = 0;
1447 			(*tp->t_linesw->l_start)(tp);
1448 		} else {
1449 			ch->ch_tx_stopped = 1;
1450 		}
1451 	}
1452 
1453 #ifdef SBSCN_DEBUG
1454 	if (sbscn_debug)
1455 		sbscn_status(ch, "sbscn_stsoft");
1456 #endif
1457 }
1458 
1459 void
1460 sbscn_soft(void *arg)
1461 {
1462 	struct sbscn_channel *ch = arg;
1463 	struct tty *tp = ch->ch_tty;
1464 
1465 	if (ch->ch_rx_ready) {
1466 		ch->ch_rx_ready = 0;
1467 		sbscn_rxsoft(ch, tp);
1468 	}
1469 
1470 	if (ch->ch_st_check) {
1471 		ch->ch_st_check = 0;
1472 		sbscn_stsoft(ch, tp);
1473 	}
1474 
1475 	if (ch->ch_tx_done) {
1476 		ch->ch_tx_done = 0;
1477 		sbscn_txsoft(ch, tp);
1478 	}
1479 }
1480 
1481 void
1482 sbscn_intr(void *arg, uint32_t status, uint32_t pc)
1483 {
1484 	struct sbscn_channel *ch = arg;
1485 	u_char *put, *end;
1486 	u_int cc;
1487 	u_char isr, sr;
1488 
1489 	/* read ISR */
1490 	isr = READ_REG(ch->ch_isr_base) & ch->ch_imr;
1491 	if (isr == 0)
1492 		return;
1493 
1494 	end = ch->ch_ebuf;
1495 	put = ch->ch_rbput;
1496 	cc = ch->ch_rbavail;
1497 
1498 	do {
1499 		u_char	iports, delta;
1500 
1501 		if (isr & 0x02) {
1502 
1503 			sr = READ_REG(ch->ch_base + 0x20);
1504 			/* XXX sr 0x01 bit must be set at this point */
1505 
1506 #if defined(DDB) || defined(KGDB)
1507 			if ((sr & 0x80) == 0x80) {
1508 #ifdef DDB
1509 				if (ISSET(ch->ch_hwflags, SBSCN_HW_CONSOLE)) {
1510 					(void)READ_REG(ch->ch_base + 0x60);
1511 					console_debugger();
1512 					continue;
1513 				}
1514 #endif
1515 #ifdef KGDB
1516 				if (ISSET(ch->ch_hwflags, SBSCN_HW_KGDB)) {
1517 					(void)READ_REG(ch->ch_base + 0x60);
1518 					kgdb_connect(1);
1519 					continue;
1520 				}
1521 #endif
1522 			}
1523 #endif /* DDB || KGDB */
1524 
1525 		    	if (!ISSET(ch->ch_rx_flags, RX_IBUF_OVERFLOWED)) {
1526 				while (cc > 0) {
1527 					put[0] = READ_REG(ch->ch_base + 0x60);
1528 					put[1] = sr;
1529 					put += 2;
1530 					if (put >= end)
1531 						put = ch->ch_rbuf;
1532 					cc--;
1533 
1534 					sr = READ_REG(ch->ch_base + 0x20);
1535 					if (!ISSET(sr, 0x02))
1536 						break;
1537 				}
1538 
1539 				/*
1540 				 * Current string of incoming characters ended
1541 				 * because no more data was available or we
1542 				 * ran out of space.  Schedule a receive event
1543 				 * if any data was received.  If we're out of
1544 				 * space, turn off receive interrupts.
1545 				 */
1546 				ch->ch_rbput = put;
1547 				ch->ch_rbavail = cc;
1548 				if (!ISSET(ch->ch_rx_flags, RX_TTY_OVERFLOWED))
1549 					ch->ch_rx_ready = 1;
1550 
1551 				/*
1552 				 * See if we are in danger of overflowing a
1553 				 * buffer. If so, use hardware flow control
1554 				 * to ease the pressure.
1555 				 */
1556 				if (!ISSET(ch->ch_rx_flags, RX_IBUF_BLOCKED) &&
1557 				    cc < ch->ch_r_hiwat) {
1558 					SET(ch->ch_rx_flags, RX_IBUF_BLOCKED);
1559 					sbscn_dohwiflow(ch);
1560 				}
1561 
1562 				/*
1563 				 * If we're out of space, disable receive
1564 				 * interrupts until the queue has drained
1565 				 * a bit.
1566 				 */
1567 				if (!cc) {
1568 					SET(ch->ch_rx_flags,
1569 					    RX_IBUF_OVERFLOWED);
1570 					CLR(ch->ch_imr, 0x02);
1571 					WRITE_REG(ch->ch_imr_base, ch->ch_imr);
1572 				}
1573 			} else {
1574 				/* XXX panic? */
1575 				CLR(ch->ch_imr, 0x02);
1576 				WRITE_REG(ch->ch_imr_base, ch->ch_imr);
1577 				continue;
1578 			}
1579 		}
1580 
1581 		if (isr & 0x01) {
1582 			CLR(ch->ch_imr, 0x01);
1583 			WRITE_REG(ch->ch_imr_base, ch->ch_imr);
1584 		}
1585 
1586 #if 0
1587 XXX
1588 		if (isr & 0x08) {
1589 			clear input signal change!
1590 		}
1591 #endif
1592 		iports = GET_INPUT_SIGNALS(ch);
1593 		delta = iports ^ ch->ch_iports;
1594 		ch->ch_iports = iports;
1595 
1596 		/*
1597 		 * Process normal status changes
1598 		 */
1599 		if (ISSET(delta, ch->ch_i_mask)) {
1600 			SET(ch->ch_iports_delta, delta);
1601 
1602 			/*
1603 			 * Stop output immediately if we lose the output
1604 			 * flow control signal or carrier detect.
1605 			 */
1606 			if (ISSET(~iports, ch->ch_i_mask)) {
1607 				ch->ch_tbc = 0;
1608 				ch->ch_heldtbc = 0;
1609 #ifdef SBSCN_DEBUG
1610 				if (sbscn_debug)
1611 					sbscn_status(ch, "sbscn_intr  ");
1612 #endif
1613 			}
1614 
1615 			ch->ch_st_check = 1;
1616 		}
1617 	} while ((isr = (READ_REG(ch->ch_isr_base) & ch->ch_imr)) != 0);
1618 
1619 	/*
1620 	 * Done handling any receive interrupts and status changes, and
1621 	 * clearing the tx-ready interrupt if it was set.  See if data can
1622 	 * be transmitted as well. Schedule tx done event if no data left
1623 	 * and tty was marked busy.
1624 	 */
1625 	sr = READ_REG(ch->ch_base + 0x20);
1626 	if (ISSET(sr, 0x4)) {
1627 
1628 		/*
1629 		 * If we've delayed a parameter change, do it now, and restart
1630 		 * output.
1631 		 */
1632 		if (ch->ch_heldchange) {
1633 			sbscn_loadchannelregs(ch);
1634 			ch->ch_heldchange = 0;
1635 			ch->ch_tbc = ch->ch_heldtbc;
1636 			ch->ch_heldtbc = 0;
1637 		}
1638 
1639 		/* Output the next chunk of the contiguous buffer, if any. */
1640 		if (ch->ch_tbc > 0) {
1641 			int wrote1;
1642 			u_char c;
1643 
1644 			wrote1 = 0;
1645 			while (ch->ch_tbc &&
1646 			    READ_REG(ch->ch_base + 0x20) & 0x04) {
1647 				wrote1 = 1;
1648 				c = *ch->ch_tba++;
1649 				ch->ch_tbc--;
1650 				WRITE_REG(ch->ch_base + 0x70, c);
1651 			}
1652 			if (wrote1) {
1653 				SET(ch->ch_imr, 0x01);
1654 				WRITE_REG(ch->ch_imr_base, ch->ch_imr);
1655 			}
1656 		} else {
1657 			/*
1658 			 * transmit completion interrupts already disabled,
1659 			 * mark the channel tx state as done.
1660 			 */
1661 			if (ch->ch_tx_busy) {
1662 				ch->ch_tx_busy = 0;
1663 				ch->ch_tx_done = 1;
1664 			}
1665 		}
1666 	}
1667 
1668 	/* Wake up the poller. */
1669 	softintr_schedule(ch->ch_si);
1670 
1671 #if NRND > 0 && defined(RND_SBSCN)
1672 	rnd_add_uint32(&ch->ch_rnd_source, isr | sr);
1673 #endif
1674 }
1675 
1676 /*
1677  * The following functions are polled getc and putc routines, shared
1678  * by the console and kgdb glue.
1679  */
1680 
1681 int
1682 sbscn_common_getc(u_long addr, int chan)
1683 {
1684 	int s = splhigh();
1685 	u_long base = MIPS_PHYS_TO_KSEG1(addr + (chan * 0x100));
1686 	int c;
1687 
1688 	/* block until a character becomes available */
1689 	while ((READ_REG(base + 0x20) & 0x01) == 0)
1690 		continue;
1691 
1692 	c = READ_REG(base + 0x60) & 0xff;
1693 	splx(s);
1694 	return (c);
1695 }
1696 
1697 void
1698 sbscn_common_putc(u_long addr, int chan, int c)
1699 {
1700 	int s = splhigh();
1701 	int timo;
1702 	u_long base = MIPS_PHYS_TO_KSEG1(addr + (chan * 0x100));
1703 
1704 	/* wait for any pending transmission to finish */
1705 	timo = 1500000;
1706 	while ((READ_REG(base + 0x20) & 0x08) == 0 && --timo)
1707 		continue;
1708 
1709 	WRITE_REG(base + 0x70, c);
1710 
1711 	/* wait for this transmission to complete */
1712 	timo = 15000000;
1713 	while ((READ_REG(base + 0x20) & 0x08) == 0 && --timo)
1714 		continue;
1715 
1716 	splx(s);
1717 }
1718 
1719 /*
1720  * Initialize UART for use as console or KGDB line.
1721  */
1722 int
1723 sbscn_init(u_long addr, int chan, int rate, tcflag_t cflag)
1724 {
1725 #if 1
1726 	u_long chanregbase = MIPS_PHYS_TO_KSEG1(addr + (chan * 0x100));
1727 	u_long imaskreg = MIPS_PHYS_TO_KSEG1(addr + 0x230 + (chan * 0x20));
1728 	u_char mode1, mode2;
1729 	u_long brc;
1730 	volatile int timo;
1731 
1732 	WRITE_REG(imaskreg, 0);			/* disable channel intrs */
1733 
1734 	/* XXX should we really do the following?  how about only if enabled? */
1735 	/* wait for any pending transmission to finish */
1736 	timo = 1500000;
1737 	while ((READ_REG(chanregbase + 0x20) & 0x08) == 0 && --timo)
1738 		continue;
1739 
1740 	/* XXX: wait a little.  THIS SHOULD NOT BE NECESSARY!!! (?) */
1741 	timo = 1500000;
1742 	while (--timo)
1743 		;
1744 
1745 	WRITE_REG(chanregbase + 0x50, 2 << 4);	/* reset receiver */
1746 	WRITE_REG(chanregbase + 0x50, 3 << 4);	/* reset transmitter */
1747 
1748 	/* set up the line for use */
1749 	(void)cflag2modes(cflag, &mode1, &mode2);
1750 	(void)sbscn_speed(rate, &brc);
1751 	WRITE_REG(chanregbase + 0x00, mode1);
1752 	WRITE_REG(chanregbase + 0x10, mode2);
1753 	WRITE_REG(chanregbase + 0x30, brc);
1754 
1755 	/* enable transmit and receive */
1756 #define	M_DUART_RX_EN			0x01
1757 #define	M_DUART_TX_EN			0x04
1758 	WRITE_REG(chanregbase + 0x50,M_DUART_RX_EN | M_DUART_TX_EN);
1759 #endif
1760 
1761 	/* XXX: wait a little.  THIS SHOULD NOT BE NECESSARY!!! (?) */
1762 	timo = 1500000;
1763 	while (--timo)
1764 		;
1765 
1766 #if 0 /* XXXCGD */
1767 	bus_space_handle_t ioh;
1768 
1769 	if (bus_space_map(iot, iobase, COM_NPORTS, 0, &ioh))
1770 		return (ENOMEM); /* ??? */
1771 
1772 	bus_space_write_1(iot, ioh, com_lcr, LCR_EERS);
1773 	bus_space_write_1(iot, ioh, com_efr, 0);
1774 	bus_space_write_1(iot, ioh, com_lcr, LCR_DLAB);
1775 	rate = comspeed(rate, frequency);
1776 	bus_space_write_1(iot, ioh, com_dlbl, rate);
1777 	bus_space_write_1(iot, ioh, com_dlbh, rate >> 8);
1778 	bus_space_write_1(iot, ioh, com_lcr, cflag2lcr(cflag));
1779 	bus_space_write_1(iot, ioh, com_mcr, MCR_DTR | MCR_RTS);
1780 	bus_space_write_1(iot, ioh, com_fifo,
1781 	    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
1782 	bus_space_write_1(iot, ioh, com_ier, 0);
1783 
1784 	*iohp = ioh;
1785 	return (0);
1786 #endif /* XXXCGD */
1787 	/* XXXCGD */
1788 	return (0);
1789 }
1790 
1791 /*
1792  * Following are all routines needed for sbscn to act as console
1793  */
1794 int
1795 sbscn_cnattach(u_long addr, int chan, int rate, tcflag_t cflag)
1796 {
1797 	int res;
1798 	static struct consdev sbscn_cons = {
1799 		NULL, NULL, sbscn_cngetc, sbscn_cnputc, sbscn_cnpollc, NULL,
1800 		    NODEV, CN_NORMAL
1801 	};
1802 
1803 	res = sbscn_init(addr, chan, rate, cflag);
1804 	if (res)
1805 		return (res);
1806 
1807 	cn_tab = &sbscn_cons;
1808 
1809 	sbscn_cons_present = 1;
1810 	sbscn_cons_addr = addr;
1811 	sbscn_cons_chan = chan;
1812 	sbscn_cons_rate = rate;
1813 	sbscn_cons_cflag = cflag;
1814 
1815 	return (0);
1816 }
1817 
1818 int
1819 sbscn_cngetc(dev_t dev)
1820 {
1821 
1822 	return (sbscn_common_getc(sbscn_cons_addr, sbscn_cons_chan));
1823 }
1824 
1825 /*
1826  * Console kernel output character routine.
1827  */
1828 void
1829 sbscn_cnputc(dev_t dev, int c)
1830 {
1831 
1832 	sbscn_common_putc(sbscn_cons_addr, sbscn_cons_chan, c);
1833 }
1834 
1835 void
1836 sbscn_cnpollc(dev_t dev, int on)
1837 {
1838 
1839 }
1840 
1841 #ifdef KGDB
1842 int
1843 sbscn_kgdb_attach(u_long addr, int chan, int rate, tcflag_t cflag)
1844 {
1845 	int res;
1846 
1847 	if (!sbscn_cons_present &&
1848 	    sbscn_cons_addr == addr && sbscn_cons_chan == chan)
1849 		return (EBUSY); /* cannot share with console */
1850 
1851 	res = sbscn_init(addr, chan, rate, cflag);
1852 	if (res)
1853 		return (res);
1854 
1855 	kgdb_attach(sbscn_kgdb_getc, sbscn_kgdb_putc, NULL);
1856 	kgdb_dev = 123; /* unneeded, only to satisfy some tests */
1857 
1858 	sbscn_kgdb_present = 1;
1859 	sbscn_kgdb_addr = addr;
1860 	sbscn_kgdb_chan = chan;
1861 
1862 	return (0);
1863 }
1864 
1865 /* ARGSUSED */
1866 int
1867 sbscn_kgdb_getc(arg)
1868 	void *arg;
1869 {
1870 
1871 	return (sbscn_common_getc(sbscn_kgdb_addr, sbscn_kgdb_chan));
1872 }
1873 
1874 /* ARGSUSED */
1875 void
1876 sbscn_kgdb_putc(arg, c)
1877 	void *arg;
1878 	int c;
1879 {
1880 
1881 	sbscn_common_getc(sbscn_kgdb_addr, sbscn_kgdb_chan, c);
1882 }
1883 #endif /* KGDB */
1884 
1885 /*
1886  * helper function to identify the sbscn channels used by
1887  * console or KGDB (and not yet autoconf attached)
1888  */
1889 int
1890 sbscn_is_console(u_long addr, int chan)
1891 {
1892 
1893 	if (sbscn_cons_present && !sbscn_cons_attached &&
1894 	    sbscn_cons_addr == addr && sbscn_cons_chan == chan)
1895 		return (1);
1896 #ifdef KGDB
1897 	if (sbscn_kgdb_present && !sbscn_kgdb_attached &&
1898 	    sbscn_kgdb_addr == addr && sbscn_kgdb_chan == chan)
1899 		return (1);
1900 #endif
1901 	return (0);
1902 }
1903