xref: /netbsd-src/sys/dev/ic/com.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: com.c,v 1.240 2006/01/08 22:19:59 dsl Exp $	*/
2 
3 /*-
4  * Copyright (c) 1998, 1999, 2004 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Charles M. Hannum.
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 /*
40  * Copyright (c) 1991 The Regents of the University of California.
41  * All rights reserved.
42  *
43  * Redistribution and use in source and binary forms, with or without
44  * modification, are permitted provided that the following conditions
45  * are met:
46  * 1. Redistributions of source code must retain the above copyright
47  *    notice, this list of conditions and the following disclaimer.
48  * 2. Redistributions in binary form must reproduce the above copyright
49  *    notice, this list of conditions and the following disclaimer in the
50  *    documentation and/or other materials provided with the distribution.
51  * 3. Neither the name of the University nor the names of its contributors
52  *    may be used to endorse or promote products derived from this software
53  *    without specific prior written permission.
54  *
55  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
56  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
57  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
58  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
59  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
60  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
61  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
62  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
63  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
64  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
65  * SUCH DAMAGE.
66  *
67  *	@(#)com.c	7.5 (Berkeley) 5/16/91
68  */
69 
70 /*
71  * COM driver, uses National Semiconductor NS16450/NS16550AF UART
72  * Supports automatic hardware flow control on StarTech ST16C650A UART
73  */
74 
75 #include <sys/cdefs.h>
76 __KERNEL_RCSID(0, "$NetBSD: com.c,v 1.240 2006/01/08 22:19:59 dsl Exp $");
77 
78 #include "opt_com.h"
79 #include "opt_ddb.h"
80 #include "opt_kgdb.h"
81 #include "opt_lockdebug.h"
82 #include "opt_multiprocessor.h"
83 #include "opt_ntp.h"
84 
85 #include "rnd.h"
86 #if NRND > 0 && defined(RND_COM)
87 #include <sys/rnd.h>
88 #endif
89 
90 /* The COM16650 option was renamed to COM_16650. */
91 #ifdef COM16650
92 #error Obsolete COM16650 option; use COM_16650 instead.
93 #endif
94 
95 /*
96  * Override cnmagic(9) macro before including <sys/systm.h>.
97  * We need to know if cn_check_magic triggered debugger, so set a flag.
98  * Callers of cn_check_magic must declare int cn_trapped = 0;
99  * XXX: this is *ugly*!
100  */
101 #define cn_trap()				\
102 	do {					\
103 		console_debugger();		\
104 		cn_trapped = 1;			\
105 	} while (/* CONSTCOND */ 0)
106 
107 #include <sys/param.h>
108 #include <sys/systm.h>
109 #include <sys/ioctl.h>
110 #include <sys/select.h>
111 #include <sys/poll.h>
112 #include <sys/tty.h>
113 #include <sys/proc.h>
114 #include <sys/user.h>
115 #include <sys/conf.h>
116 #include <sys/file.h>
117 #include <sys/uio.h>
118 #include <sys/kernel.h>
119 #include <sys/syslog.h>
120 #include <sys/device.h>
121 #include <sys/malloc.h>
122 #include <sys/timepps.h>
123 #include <sys/vnode.h>
124 
125 #include <machine/intr.h>
126 #include <machine/bus.h>
127 
128 #include <dev/ic/comreg.h>
129 #include <dev/ic/comvar.h>
130 #include <dev/ic/ns16550reg.h>
131 #include <dev/ic/st16650reg.h>
132 #ifdef COM_HAYESP
133 #include <dev/ic/hayespreg.h>
134 #endif
135 #define	com_lcr	com_cfcr
136 #include <dev/cons.h>
137 
138 #ifdef COM_HAYESP
139 int comprobeHAYESP(bus_space_handle_t hayespioh, struct com_softc *sc);
140 #endif
141 
142 static void com_enable_debugport(struct com_softc *);
143 
144 void	com_config(struct com_softc *);
145 void	com_shutdown(struct com_softc *);
146 int	comspeed(long, long, int);
147 static	u_char	cflag2lcr(tcflag_t);
148 int	comparam(struct tty *, struct termios *);
149 void	comstart(struct tty *);
150 int	comhwiflow(struct tty *, int);
151 
152 void	com_loadchannelregs(struct com_softc *);
153 void	com_hwiflow(struct com_softc *);
154 void	com_break(struct com_softc *, int);
155 void	com_modem(struct com_softc *, int);
156 void	tiocm_to_com(struct com_softc *, u_long, int);
157 int	com_to_tiocm(struct com_softc *);
158 void	com_iflush(struct com_softc *);
159 
160 int	com_common_getc(dev_t, bus_space_tag_t, bus_space_handle_t);
161 void	com_common_putc(dev_t, bus_space_tag_t, bus_space_handle_t, int);
162 
163 int	cominit(bus_space_tag_t, bus_addr_t, int, int, int, tcflag_t,
164 	    bus_space_handle_t *);
165 
166 int	comcngetc(dev_t);
167 void	comcnputc(dev_t, int);
168 void	comcnpollc(dev_t, int);
169 
170 #define	integrate	static inline
171 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
172 void 	comsoft(void *);
173 #else
174 #ifndef __NO_SOFT_SERIAL_INTERRUPT
175 void 	comsoft(void);
176 #else
177 void 	comsoft(void *);
178 static struct callout comsoft_callout = CALLOUT_INITIALIZER;
179 #endif
180 #endif
181 integrate void com_rxsoft(struct com_softc *, struct tty *);
182 integrate void com_txsoft(struct com_softc *, struct tty *);
183 integrate void com_stsoft(struct com_softc *, struct tty *);
184 integrate void com_schedrx(struct com_softc *);
185 void	comdiag(void *);
186 
187 extern struct cfdriver com_cd;
188 
189 dev_type_open(comopen);
190 dev_type_close(comclose);
191 dev_type_read(comread);
192 dev_type_write(comwrite);
193 dev_type_ioctl(comioctl);
194 dev_type_stop(comstop);
195 dev_type_tty(comtty);
196 dev_type_poll(compoll);
197 
198 const struct cdevsw com_cdevsw = {
199 	comopen, comclose, comread, comwrite, comioctl,
200 	comstop, comtty, compoll, nommap, ttykqfilter, D_TTY
201 };
202 
203 /*
204  * Make this an option variable one can patch.
205  * But be warned:  this must be a power of 2!
206  */
207 u_int com_rbuf_size = COM_RING_SIZE;
208 
209 /* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
210 u_int com_rbuf_hiwat = (COM_RING_SIZE * 1) / 4;
211 u_int com_rbuf_lowat = (COM_RING_SIZE * 3) / 4;
212 
213 static bus_addr_t	comconsaddr;
214 static bus_space_tag_t comconstag;
215 static bus_space_handle_t comconsioh;
216 static int	comconsattached;
217 static int comconsrate;
218 static tcflag_t comconscflag;
219 static struct cnm_state com_cnm_state;
220 
221 static int ppscap =
222 	PPS_TSFMT_TSPEC |
223 	PPS_CAPTUREASSERT |
224 	PPS_CAPTURECLEAR |
225 	PPS_OFFSETASSERT | PPS_OFFSETCLEAR;
226 
227 #ifndef __HAVE_GENERIC_SOFT_INTERRUPTS
228 #ifdef __NO_SOFT_SERIAL_INTERRUPT
229 volatile int	com_softintr_scheduled;
230 #endif
231 #endif
232 
233 #ifdef KGDB
234 #include <sys/kgdb.h>
235 
236 static bus_addr_t com_kgdb_addr;
237 static bus_space_tag_t com_kgdb_iot;
238 static bus_space_handle_t com_kgdb_ioh;
239 static int com_kgdb_attached;
240 
241 int	com_kgdb_getc(void *);
242 void	com_kgdb_putc(void *, int);
243 #endif /* KGDB */
244 
245 #define	COMUNIT_MASK	0x7ffff
246 #define	COMDIALOUT_MASK	0x80000
247 
248 #define	COMUNIT(x)	(minor(x) & COMUNIT_MASK)
249 #define	COMDIALOUT(x)	(minor(x) & COMDIALOUT_MASK)
250 
251 #define	COM_ISALIVE(sc)	((sc)->enabled != 0 && \
252 			 ISSET((sc)->sc_dev.dv_flags, DVF_ACTIVE))
253 
254 #define	BR	BUS_SPACE_BARRIER_READ
255 #define	BW	BUS_SPACE_BARRIER_WRITE
256 #define COM_BARRIER(t, h, f) bus_space_barrier((t), (h), 0, COM_NPORTS, (f))
257 
258 #define COM_LOCK(sc) simple_lock(&(sc)->sc_lock)
259 #define COM_UNLOCK(sc) simple_unlock(&(sc)->sc_lock)
260 
261 /*ARGSUSED*/
262 int
263 comspeed(long speed, long frequency, int type)
264 {
265 #define	divrnd(n, q)	(((n)*2/(q)+1)/2)	/* divide and round off */
266 
267 	int x, err;
268 
269 #if 0
270 	if (speed == 0)
271 		return (0);
272 #endif
273 	if (speed <= 0)
274 		return (-1);
275 	x = divrnd(frequency / 16, speed);
276 	if (x <= 0)
277 		return (-1);
278 	err = divrnd(((quad_t)frequency) * 1000 / 16, speed * x) - 1000;
279 	if (err < 0)
280 		err = -err;
281 	if (err > COM_TOLERANCE)
282 		return (-1);
283 	return (x);
284 
285 #undef	divrnd
286 }
287 
288 #ifdef COM_DEBUG
289 int	com_debug = 0;
290 
291 void comstatus(struct com_softc *, const char *);
292 void
293 comstatus(struct com_softc *sc, const char *str)
294 {
295 	struct tty *tp = sc->sc_tty;
296 
297 	printf("%s: %s %cclocal  %cdcd %cts_carr_on %cdtr %ctx_stopped\n",
298 	    sc->sc_dev.dv_xname, str,
299 	    ISSET(tp->t_cflag, CLOCAL) ? '+' : '-',
300 	    ISSET(sc->sc_msr, MSR_DCD) ? '+' : '-',
301 	    ISSET(tp->t_state, TS_CARR_ON) ? '+' : '-',
302 	    ISSET(sc->sc_mcr, MCR_DTR) ? '+' : '-',
303 	    sc->sc_tx_stopped ? '+' : '-');
304 
305 	printf("%s: %s %ccrtscts %ccts %cts_ttstop  %crts rx_flags=0x%x\n",
306 	    sc->sc_dev.dv_xname, str,
307 	    ISSET(tp->t_cflag, CRTSCTS) ? '+' : '-',
308 	    ISSET(sc->sc_msr, MSR_CTS) ? '+' : '-',
309 	    ISSET(tp->t_state, TS_TTSTOP) ? '+' : '-',
310 	    ISSET(sc->sc_mcr, MCR_RTS) ? '+' : '-',
311 	    sc->sc_rx_flags);
312 }
313 #endif
314 
315 int
316 comprobe1(bus_space_tag_t iot, bus_space_handle_t ioh)
317 {
318 
319 	/* force access to id reg */
320 	bus_space_write_1(iot, ioh, com_lcr, LCR_8BITS);
321 	bus_space_write_1(iot, ioh, com_iir, 0);
322 	if ((bus_space_read_1(iot, ioh, com_lcr) != LCR_8BITS) ||
323 	    (bus_space_read_1(iot, ioh, com_iir) & 0x38))
324 		return (0);
325 
326 	return (1);
327 }
328 
329 #ifdef COM_HAYESP
330 int
331 comprobeHAYESP(bus_space_handle_t hayespioh, struct com_softc *sc)
332 {
333 	char	val, dips;
334 	int	combaselist[] = { 0x3f8, 0x2f8, 0x3e8, 0x2e8 };
335 	bus_space_tag_t iot = sc->sc_iot;
336 
337 	/*
338 	 * Hayes ESP cards have two iobases.  One is for compatibility with
339 	 * 16550 serial chips, and at the same ISA PC base addresses.  The
340 	 * other is for ESP-specific enhanced features, and lies at a
341 	 * different addressing range entirely (0x140, 0x180, 0x280, or 0x300).
342 	 */
343 
344 	/* Test for ESP signature */
345 	if ((bus_space_read_1(iot, hayespioh, 0) & 0xf3) == 0)
346 		return (0);
347 
348 	/*
349 	 * ESP is present at ESP enhanced base address; unknown com port
350 	 */
351 
352 	/* Get the dip-switch configurations */
353 	bus_space_write_1(iot, hayespioh, HAYESP_CMD1, HAYESP_GETDIPS);
354 	dips = bus_space_read_1(iot, hayespioh, HAYESP_STATUS1);
355 
356 	/* Determine which com port this ESP card services: bits 0,1 of  */
357 	/*  dips is the port # (0-3); combaselist[val] is the com_iobase */
358 	if (sc->sc_iobase != combaselist[dips & 0x03])
359 		return (0);
360 
361 	printf(": ESP");
362 
363  	/* Check ESP Self Test bits. */
364 	/* Check for ESP version 2.0: bits 4,5,6 == 010 */
365 	bus_space_write_1(iot, hayespioh, HAYESP_CMD1, HAYESP_GETTEST);
366 	val = bus_space_read_1(iot, hayespioh, HAYESP_STATUS1); /* Clear reg1 */
367 	val = bus_space_read_1(iot, hayespioh, HAYESP_STATUS2);
368 	if ((val & 0x70) < 0x20) {
369 		printf("-old (%o)", val & 0x70);
370 		/* we do not support the necessary features */
371 		return (0);
372 	}
373 
374 	/* Check for ability to emulate 16550: bit 8 == 1 */
375 	if ((dips & 0x80) == 0) {
376 		printf(" slave");
377 		/* XXX Does slave really mean no 16550 support?? */
378 		return (0);
379 	}
380 
381 	/*
382 	 * If we made it this far, we are a full-featured ESP v2.0 (or
383 	 * better), at the correct com port address.
384 	 */
385 
386 	sc->sc_type = COM_TYPE_HAYESP;
387 	printf(", 1024 byte fifo\n");
388 	return (1);
389 }
390 #endif
391 
392 static void
393 com_enable_debugport(struct com_softc *sc)
394 {
395 	int s;
396 
397 	/* Turn on line break interrupt, set carrier. */
398 	s = splserial();
399 	COM_LOCK(sc);
400 	sc->sc_ier = IER_ERXRDY;
401 #ifdef COM_PXA2X0
402 	if (sc->sc_type == COM_TYPE_PXA2x0)
403 		sc->sc_ier |= IER_EUART | IER_ERXTOUT;
404 #endif
405 	bus_space_write_1(sc->sc_iot, sc->sc_ioh, com_ier, sc->sc_ier);
406 	SET(sc->sc_mcr, MCR_DTR | MCR_RTS);
407 	bus_space_write_1(sc->sc_iot, sc->sc_ioh, com_mcr, sc->sc_mcr);
408 	COM_UNLOCK(sc);
409 	splx(s);
410 }
411 
412 void
413 com_attach_subr(struct com_softc *sc)
414 {
415 	bus_addr_t iobase = sc->sc_iobase;
416 	bus_space_tag_t iot = sc->sc_iot;
417 	bus_space_handle_t ioh = sc->sc_ioh;
418 	struct tty *tp;
419 #ifdef COM_16650
420 	u_int8_t lcr;
421 #endif
422 #ifdef COM_HAYESP
423 	int	hayesp_ports[] = { 0x140, 0x180, 0x280, 0x300, 0 };
424 	int	*hayespp;
425 #endif
426 	const char *fifo_msg = NULL;
427 
428 	callout_init(&sc->sc_diag_callout);
429 	simple_lock_init(&sc->sc_lock);
430 
431 	/* Disable interrupts before configuring the device. */
432 #ifdef COM_PXA2X0
433 	if (sc->sc_type == COM_TYPE_PXA2x0)
434 		sc->sc_ier = IER_EUART;
435 	else
436 #endif
437 		sc->sc_ier = 0;
438 	bus_space_write_1(iot, ioh, com_ier, sc->sc_ier);
439 
440 	if (iot == comconstag && iobase == comconsaddr) {
441 		comconsattached = 1;
442 
443 		/* Make sure the console is always "hardwired". */
444 		delay(10000);			/* wait for output to finish */
445 		SET(sc->sc_hwflags, COM_HW_CONSOLE);
446 		SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
447 	}
448 
449 #ifdef COM_HAYESP
450 	sc->sc_prescaler = 0;			/* set prescaler to x1. */
451 
452 	/* Look for a Hayes ESP board. */
453 	for (hayespp = hayesp_ports; *hayespp != 0; hayespp++) {
454 		bus_space_handle_t hayespioh;
455 
456 #define	HAYESP_NPORTS	8			/* XXX XXX XXX ??? ??? ??? */
457 		if (bus_space_map(iot, *hayespp, HAYESP_NPORTS, 0, &hayespioh))
458 			continue;
459 		if (comprobeHAYESP(hayespioh, sc)) {
460 			sc->sc_hayespioh = hayespioh;
461 			sc->sc_fifolen = 1024;
462 
463 			break;
464 		}
465 		bus_space_unmap(iot, hayespioh, HAYESP_NPORTS);
466 	}
467 	/* No ESP; look for other things. */
468 	if (sc->sc_type != COM_TYPE_HAYESP) {
469 #endif
470 	sc->sc_fifolen = 1;
471 	/* look for a NS 16550AF UART with FIFOs */
472 	bus_space_write_1(iot, ioh, com_fifo,
473 	    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_14);
474 	delay(100);
475 	if (ISSET(bus_space_read_1(iot, ioh, com_iir), IIR_FIFO_MASK)
476 	    == IIR_FIFO_MASK)
477 		if (ISSET(bus_space_read_1(iot, ioh, com_fifo), FIFO_TRIGGER_14)
478 		    == FIFO_TRIGGER_14) {
479 			SET(sc->sc_hwflags, COM_HW_FIFO);
480 
481 #ifdef COM_16650
482 			/*
483 			 * IIR changes into the EFR if LCR is set to LCR_EERS
484 			 * on 16650s. We also know IIR != 0 at this point.
485 			 * Write 0 into the EFR, and read it. If the result
486 			 * is 0, we have a 16650.
487 			 *
488 			 * Older 16650s were broken; the test to detect them
489 			 * is taken from the Linux driver. Apparently
490 			 * setting DLAB enable gives access to the EFR on
491 			 * these chips.
492 			 */
493 			lcr = bus_space_read_1(iot, ioh, com_lcr);
494 			bus_space_write_1(iot, ioh, com_lcr, LCR_EERS);
495 			bus_space_write_1(iot, ioh, com_efr, 0);
496 			if (bus_space_read_1(iot, ioh, com_efr) == 0) {
497 				bus_space_write_1(iot, ioh, com_lcr,
498 				    lcr | LCR_DLAB);
499 				if (bus_space_read_1(iot, ioh, com_efr) == 0) {
500 					CLR(sc->sc_hwflags, COM_HW_FIFO);
501 					sc->sc_fifolen = 0;
502 				} else {
503 					SET(sc->sc_hwflags, COM_HW_FLOW);
504 					sc->sc_fifolen = 32;
505 				}
506 			} else
507 #endif
508 				sc->sc_fifolen = 16;
509 
510 #ifdef COM_16650
511 			bus_space_write_1(iot, ioh, com_lcr, lcr);
512 			if (sc->sc_fifolen == 0)
513 				fifo_msg = "st16650, broken fifo";
514 			else if (sc->sc_fifolen == 32)
515 				fifo_msg = "st16650a, working fifo";
516 			else
517 #endif
518 				fifo_msg = "ns16550a, working fifo";
519 		} else
520 			fifo_msg = "ns16550, broken fifo";
521 	else
522 		fifo_msg = "ns8250 or ns16450, no fifo";
523 	bus_space_write_1(iot, ioh, com_fifo, 0);
524 	/*
525 	 * Some chips will clear down both Tx and Rx FIFOs when zero is
526 	 * written to com_fifo. If this chip is the console, writing zero
527 	 * results in some of the chip/FIFO description being lost, so delay
528 	 * printing it until now.
529 	 */
530 	delay(10);
531 	aprint_normal(": %s\n", fifo_msg);
532 	if (ISSET(sc->sc_hwflags, COM_HW_TXFIFO_DISABLE)) {
533 		sc->sc_fifolen = 1;
534 		aprint_normal("%s: txfifo disabled\n", sc->sc_dev.dv_xname);
535 	}
536 #ifdef COM_HAYESP
537 	}
538 #endif
539 
540 	tp = ttymalloc();
541 	tp->t_oproc = comstart;
542 	tp->t_param = comparam;
543 	tp->t_hwiflow = comhwiflow;
544 
545 	sc->sc_tty = tp;
546 	sc->sc_rbuf = malloc(com_rbuf_size << 1, M_DEVBUF, M_NOWAIT);
547 	sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
548 	sc->sc_rbavail = com_rbuf_size;
549 	if (sc->sc_rbuf == NULL) {
550 		aprint_error("%s: unable to allocate ring buffer\n",
551 		    sc->sc_dev.dv_xname);
552 		return;
553 	}
554 	sc->sc_ebuf = sc->sc_rbuf + (com_rbuf_size << 1);
555 
556 	tty_attach(tp);
557 
558 	if (!ISSET(sc->sc_hwflags, COM_HW_NOIEN))
559 		SET(sc->sc_mcr, MCR_IENABLE);
560 
561 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
562 		int maj;
563 
564 		/* locate the major number */
565 		maj = cdevsw_lookup_major(&com_cdevsw);
566 
567 		tp->t_dev = cn_tab->cn_dev = makedev(maj, sc->sc_dev.dv_unit);
568 
569 		aprint_normal("%s: console\n", sc->sc_dev.dv_xname);
570 	}
571 
572 #ifdef KGDB
573 	/*
574 	 * Allow kgdb to "take over" this port.  If this is
575 	 * not the console and is the kgdb device, it has
576 	 * exclusive use.  If it's the console _and_ the
577 	 * kgdb device, it doesn't.
578 	 */
579 	if (iot == com_kgdb_iot && iobase == com_kgdb_addr) {
580 		if (!ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
581 			com_kgdb_attached = 1;
582 
583 			SET(sc->sc_hwflags, COM_HW_KGDB);
584 		}
585 		aprint_normal("%s: kgdb\n", sc->sc_dev.dv_xname);
586 	}
587 #endif
588 
589 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
590 	sc->sc_si = softintr_establish(IPL_SOFTSERIAL, comsoft, sc);
591 #endif
592 
593 #if NRND > 0 && defined(RND_COM)
594 	rnd_attach_source(&sc->rnd_source, sc->sc_dev.dv_xname,
595 			  RND_TYPE_TTY, 0);
596 #endif
597 
598 	/* if there are no enable/disable functions, assume the device
599 	   is always enabled */
600 	if (!sc->enable)
601 		sc->enabled = 1;
602 
603 	com_config(sc);
604 
605 	SET(sc->sc_hwflags, COM_HW_DEV_OK);
606 }
607 
608 void
609 com_config(struct com_softc *sc)
610 {
611 	bus_space_tag_t iot = sc->sc_iot;
612 	bus_space_handle_t ioh = sc->sc_ioh;
613 
614 	/* Disable interrupts before configuring the device. */
615 #ifdef COM_PXA2X0
616 	if (sc->sc_type == COM_TYPE_PXA2x0)
617 		sc->sc_ier = IER_EUART;
618 	else
619 #endif
620 		sc->sc_ier = 0;
621 	bus_space_write_1(iot, ioh, com_ier, sc->sc_ier);
622 	(void) bus_space_read_1(iot, ioh, com_iir);
623 
624 #ifdef COM_HAYESP
625 	/* Look for a Hayes ESP board. */
626 	if (sc->sc_type == COM_TYPE_HAYESP) {
627 		sc->sc_fifolen = 1024;
628 
629 		/* Set 16550 compatibility mode */
630 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD1,
631 				  HAYESP_SETMODE);
632 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD2,
633 				  HAYESP_MODE_FIFO|HAYESP_MODE_RTS|
634 				  HAYESP_MODE_SCALE);
635 
636 		/* Set RTS/CTS flow control */
637 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD1,
638 				  HAYESP_SETFLOWTYPE);
639 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD2,
640 				  HAYESP_FLOW_RTS);
641 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD2,
642 				  HAYESP_FLOW_CTS);
643 
644 		/* Set flow control levels */
645 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD1,
646 				  HAYESP_SETRXFLOW);
647 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD2,
648 				  HAYESP_HIBYTE(HAYESP_RXHIWMARK));
649 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD2,
650 				  HAYESP_LOBYTE(HAYESP_RXHIWMARK));
651 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD2,
652 				  HAYESP_HIBYTE(HAYESP_RXLOWMARK));
653 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD2,
654 				  HAYESP_LOBYTE(HAYESP_RXLOWMARK));
655 	}
656 #endif
657 
658 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE|COM_HW_KGDB))
659 		com_enable_debugport(sc);
660 }
661 
662 int
663 com_detach(struct device *self, int flags)
664 {
665 	struct com_softc *sc = (struct com_softc *)self;
666 	int maj, mn;
667 
668 	/* locate the major number */
669 	maj = cdevsw_lookup_major(&com_cdevsw);
670 
671 	/* Nuke the vnodes for any open instances. */
672 	mn = self->dv_unit;
673 	vdevgone(maj, mn, mn, VCHR);
674 
675 	mn |= COMDIALOUT_MASK;
676 	vdevgone(maj, mn, mn, VCHR);
677 
678 	if (sc->sc_rbuf == NULL) {
679 		/*
680 		 * Ring buffer allocation failed in the com_attach_subr,
681 		 * only the tty is allocated, and nothing else.
682 		 */
683 		ttyfree(sc->sc_tty);
684 		return 0;
685 	}
686 
687 	/* Free the receive buffer. */
688 	free(sc->sc_rbuf, M_DEVBUF);
689 
690 	/* Detach and free the tty. */
691 	tty_detach(sc->sc_tty);
692 	ttyfree(sc->sc_tty);
693 
694 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
695 	/* Unhook the soft interrupt handler. */
696 	softintr_disestablish(sc->sc_si);
697 #endif
698 
699 #if NRND > 0 && defined(RND_COM)
700 	/* Unhook the entropy source. */
701 	rnd_detach_source(&sc->rnd_source);
702 #endif
703 
704 	return (0);
705 }
706 
707 int
708 com_activate(struct device *self, enum devact act)
709 {
710 	struct com_softc *sc = (struct com_softc *)self;
711 	int s, rv = 0;
712 
713 	s = splserial();
714 	COM_LOCK(sc);
715 	switch (act) {
716 	case DVACT_ACTIVATE:
717 		rv = EOPNOTSUPP;
718 		break;
719 
720 	case DVACT_DEACTIVATE:
721 		if (sc->sc_hwflags & (COM_HW_CONSOLE|COM_HW_KGDB)) {
722 			rv = EBUSY;
723 			break;
724 		}
725 
726 		if (sc->disable != NULL && sc->enabled != 0) {
727 			(*sc->disable)(sc);
728 			sc->enabled = 0;
729 		}
730 		break;
731 	}
732 
733 	COM_UNLOCK(sc);
734 	splx(s);
735 	return (rv);
736 }
737 
738 void
739 com_shutdown(struct com_softc *sc)
740 {
741 	struct tty *tp = sc->sc_tty;
742 	int s;
743 
744 	s = splserial();
745 	COM_LOCK(sc);
746 
747 	/* If we were asserting flow control, then deassert it. */
748 	SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
749 	com_hwiflow(sc);
750 
751 	/* Clear any break condition set with TIOCSBRK. */
752 	com_break(sc, 0);
753 
754 	/* Turn off PPS capture on last close. */
755 	sc->sc_ppsmask = 0;
756 	sc->ppsparam.mode = 0;
757 
758 	/*
759 	 * Hang up if necessary.  Wait a bit, so the other side has time to
760 	 * notice even if we immediately open the port again.
761 	 * Avoid tsleeping above splhigh().
762 	 */
763 	if (ISSET(tp->t_cflag, HUPCL)) {
764 		com_modem(sc, 0);
765 		COM_UNLOCK(sc);
766 		splx(s);
767 		/* XXX tsleep will only timeout */
768 		(void) tsleep(sc, TTIPRI, ttclos, hz);
769 		s = splserial();
770 		COM_LOCK(sc);
771 	}
772 
773 	/* Turn off interrupts. */
774 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
775 		sc->sc_ier = IER_ERXRDY; /* interrupt on break */
776 #ifdef COM_PXA2X0
777 		if (sc->sc_type == COM_TYPE_PXA2x0)
778 			sc->sc_ier |= IER_ERXTOUT;
779 #endif
780 	} else
781 		sc->sc_ier = 0;
782 
783 #ifdef COM_PXA2X0
784 	if (sc->sc_type == COM_TYPE_PXA2x0)
785 		sc->sc_ier |= IER_EUART;
786 #endif
787 
788 	bus_space_write_1(sc->sc_iot, sc->sc_ioh, com_ier, sc->sc_ier);
789 
790 	if (sc->disable) {
791 #ifdef DIAGNOSTIC
792 		if (!sc->enabled)
793 			panic("com_shutdown: not enabled?");
794 #endif
795 		(*sc->disable)(sc);
796 		sc->enabled = 0;
797 	}
798 	COM_UNLOCK(sc);
799 	splx(s);
800 }
801 
802 int
803 comopen(dev_t dev, int flag, int mode, struct lwp *l)
804 {
805 	struct com_softc *sc;
806 	struct tty *tp;
807 	int s, s2;
808 	int error;
809 
810 	sc = device_lookup(&com_cd, COMUNIT(dev));
811 	if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK) ||
812 		sc->sc_rbuf == NULL)
813 		return (ENXIO);
814 
815 	if (ISSET(sc->sc_dev.dv_flags, DVF_ACTIVE) == 0)
816 		return (ENXIO);
817 
818 #ifdef KGDB
819 	/*
820 	 * If this is the kgdb port, no other use is permitted.
821 	 */
822 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
823 		return (EBUSY);
824 #endif
825 
826 	tp = sc->sc_tty;
827 
828 	if (ISSET(tp->t_state, TS_ISOPEN) &&
829 	    ISSET(tp->t_state, TS_XCLUDE) &&
830 		suser(l->l_proc->p_ucred, &l->l_proc->p_acflag) != 0)
831 		return (EBUSY);
832 
833 	s = spltty();
834 
835 	/*
836 	 * Do the following iff this is a first open.
837 	 */
838 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
839 		struct termios t;
840 
841 		tp->t_dev = dev;
842 
843 		s2 = splserial();
844 		COM_LOCK(sc);
845 
846 		if (sc->enable) {
847 			if ((*sc->enable)(sc)) {
848 				COM_UNLOCK(sc);
849 				splx(s2);
850 				splx(s);
851 				printf("%s: device enable failed\n",
852 				       sc->sc_dev.dv_xname);
853 				return (EIO);
854 			}
855 			sc->enabled = 1;
856 			com_config(sc);
857 		}
858 
859 		/* Turn on interrupts. */
860 		sc->sc_ier = IER_ERXRDY | IER_ERLS | IER_EMSC;
861 #ifdef COM_PXA2X0
862 		if (sc->sc_type == COM_TYPE_PXA2x0)
863 			sc->sc_ier |= IER_EUART | IER_ERXTOUT;
864 #endif
865 		bus_space_write_1(sc->sc_iot, sc->sc_ioh, com_ier, sc->sc_ier);
866 
867 		/* Fetch the current modem control status, needed later. */
868 		sc->sc_msr = bus_space_read_1(sc->sc_iot, sc->sc_ioh, com_msr);
869 
870 		/* Clear PPS capture state on first open. */
871 		sc->sc_ppsmask = 0;
872 		sc->ppsparam.mode = 0;
873 
874 		COM_UNLOCK(sc);
875 		splx(s2);
876 
877 		/*
878 		 * Initialize the termios status to the defaults.  Add in the
879 		 * sticky bits from TIOCSFLAGS.
880 		 */
881 		if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
882 			t.c_ospeed = comconsrate;
883 			t.c_cflag = comconscflag;
884 		} else {
885 			t.c_ospeed = TTYDEF_SPEED;
886 			t.c_cflag = TTYDEF_CFLAG;
887 		}
888 		t.c_ispeed = t.c_ospeed;
889 		if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
890 			SET(t.c_cflag, CLOCAL);
891 		if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
892 			SET(t.c_cflag, CRTSCTS);
893 		if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
894 			SET(t.c_cflag, MDMBUF);
895 		/* Make sure comparam() will do something. */
896 		tp->t_ospeed = 0;
897 		(void) comparam(tp, &t);
898 		tp->t_iflag = TTYDEF_IFLAG;
899 		tp->t_oflag = TTYDEF_OFLAG;
900 		tp->t_lflag = TTYDEF_LFLAG;
901 		ttychars(tp);
902 		ttsetwater(tp);
903 
904 		s2 = splserial();
905 		COM_LOCK(sc);
906 
907 		/*
908 		 * Turn on DTR.  We must always do this, even if carrier is not
909 		 * present, because otherwise we'd have to use TIOCSDTR
910 		 * immediately after setting CLOCAL, which applications do not
911 		 * expect.  We always assert DTR while the device is open
912 		 * unless explicitly requested to deassert it.
913 		 */
914 		com_modem(sc, 1);
915 
916 		/* Clear the input ring, and unblock. */
917 		sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
918 		sc->sc_rbavail = com_rbuf_size;
919 		com_iflush(sc);
920 		CLR(sc->sc_rx_flags, RX_ANY_BLOCK);
921 		com_hwiflow(sc);
922 
923 #ifdef COM_DEBUG
924 		if (com_debug)
925 			comstatus(sc, "comopen  ");
926 #endif
927 
928 		COM_UNLOCK(sc);
929 		splx(s2);
930 	}
931 
932 	splx(s);
933 
934 	error = ttyopen(tp, COMDIALOUT(dev), ISSET(flag, O_NONBLOCK));
935 	if (error)
936 		goto bad;
937 
938 	error = (*tp->t_linesw->l_open)(dev, tp);
939 	if (error)
940 		goto bad;
941 
942 	return (0);
943 
944 bad:
945 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
946 		/*
947 		 * We failed to open the device, and nobody else had it opened.
948 		 * Clean up the state as appropriate.
949 		 */
950 		com_shutdown(sc);
951 	}
952 
953 	return (error);
954 }
955 
956 int
957 comclose(dev_t dev, int flag, int mode, struct lwp *l)
958 {
959 	struct com_softc *sc = device_lookup(&com_cd, COMUNIT(dev));
960 	struct tty *tp = sc->sc_tty;
961 
962 	/* XXX This is for cons.c. */
963 	if (!ISSET(tp->t_state, TS_ISOPEN))
964 		return (0);
965 
966 	(*tp->t_linesw->l_close)(tp, flag);
967 	ttyclose(tp);
968 
969 	if (COM_ISALIVE(sc) == 0)
970 		return (0);
971 
972 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
973 		/*
974 		 * Although we got a last close, the device may still be in
975 		 * use; e.g. if this was the dialout node, and there are still
976 		 * processes waiting for carrier on the non-dialout node.
977 		 */
978 		com_shutdown(sc);
979 	}
980 
981 	return (0);
982 }
983 
984 int
985 comread(dev_t dev, struct uio *uio, int flag)
986 {
987 	struct com_softc *sc = device_lookup(&com_cd, COMUNIT(dev));
988 	struct tty *tp = sc->sc_tty;
989 
990 	if (COM_ISALIVE(sc) == 0)
991 		return (EIO);
992 
993 	return ((*tp->t_linesw->l_read)(tp, uio, flag));
994 }
995 
996 int
997 comwrite(dev_t dev, struct uio *uio, int flag)
998 {
999 	struct com_softc *sc = device_lookup(&com_cd, COMUNIT(dev));
1000 	struct tty *tp = sc->sc_tty;
1001 
1002 	if (COM_ISALIVE(sc) == 0)
1003 		return (EIO);
1004 
1005 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
1006 }
1007 
1008 int
1009 compoll(dev_t dev, int events, struct lwp *l)
1010 {
1011 	struct com_softc *sc = device_lookup(&com_cd, COMUNIT(dev));
1012 	struct tty *tp = sc->sc_tty;
1013 
1014 	if (COM_ISALIVE(sc) == 0)
1015 		return (POLLHUP);
1016 
1017 	return ((*tp->t_linesw->l_poll)(tp, events, l));
1018 }
1019 
1020 struct tty *
1021 comtty(dev_t dev)
1022 {
1023 	struct com_softc *sc = device_lookup(&com_cd, COMUNIT(dev));
1024 	struct tty *tp = sc->sc_tty;
1025 
1026 	return (tp);
1027 }
1028 
1029 int
1030 comioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct lwp *l)
1031 {
1032 	struct com_softc *sc = device_lookup(&com_cd, COMUNIT(dev));
1033 	struct tty *tp = sc->sc_tty;
1034 	struct proc *p = l->l_proc;
1035 	int error;
1036 	int s;
1037 
1038 	if (COM_ISALIVE(sc) == 0)
1039 		return (EIO);
1040 
1041 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
1042 	if (error != EPASSTHROUGH)
1043 		return (error);
1044 
1045 	error = ttioctl(tp, cmd, data, flag, l);
1046 	if (error != EPASSTHROUGH)
1047 		return (error);
1048 
1049 	error = 0;
1050 
1051 	s = splserial();
1052 	COM_LOCK(sc);
1053 
1054 	switch (cmd) {
1055 	case TIOCSBRK:
1056 		com_break(sc, 1);
1057 		break;
1058 
1059 	case TIOCCBRK:
1060 		com_break(sc, 0);
1061 		break;
1062 
1063 	case TIOCSDTR:
1064 		com_modem(sc, 1);
1065 		break;
1066 
1067 	case TIOCCDTR:
1068 		com_modem(sc, 0);
1069 		break;
1070 
1071 	case TIOCGFLAGS:
1072 		*(int *)data = sc->sc_swflags;
1073 		break;
1074 
1075 	case TIOCSFLAGS:
1076 		error = suser(p->p_ucred, &p->p_acflag);
1077 		if (error)
1078 			break;
1079 		sc->sc_swflags = *(int *)data;
1080 		break;
1081 
1082 	case TIOCMSET:
1083 	case TIOCMBIS:
1084 	case TIOCMBIC:
1085 		tiocm_to_com(sc, cmd, *(int *)data);
1086 		break;
1087 
1088 	case TIOCMGET:
1089 		*(int *)data = com_to_tiocm(sc);
1090 		break;
1091 
1092 	case PPS_IOC_CREATE:
1093 		break;
1094 
1095 	case PPS_IOC_DESTROY:
1096 		break;
1097 
1098 	case PPS_IOC_GETPARAMS: {
1099 		pps_params_t *pp;
1100 		pp = (pps_params_t *)data;
1101 		*pp = sc->ppsparam;
1102 		break;
1103 	}
1104 
1105 	case PPS_IOC_SETPARAMS: {
1106 	  	pps_params_t *pp;
1107 		int mode;
1108 		pp = (pps_params_t *)data;
1109 		if (pp->mode & ~ppscap) {
1110 			error = EINVAL;
1111 			break;
1112 		}
1113 		sc->ppsparam = *pp;
1114 	 	/*
1115 		 * Compute msr masks from user-specified timestamp state.
1116 		 */
1117 		mode = sc->ppsparam.mode;
1118 		switch (mode & PPS_CAPTUREBOTH) {
1119 		case 0:
1120 			sc->sc_ppsmask = 0;
1121 			break;
1122 
1123 		case PPS_CAPTUREASSERT:
1124 			sc->sc_ppsmask = MSR_DCD;
1125 			sc->sc_ppsassert = MSR_DCD;
1126 			sc->sc_ppsclear = -1;
1127 			break;
1128 
1129 		case PPS_CAPTURECLEAR:
1130 			sc->sc_ppsmask = MSR_DCD;
1131 			sc->sc_ppsassert = -1;
1132 			sc->sc_ppsclear = 0;
1133 			break;
1134 
1135 		case PPS_CAPTUREBOTH:
1136 			sc->sc_ppsmask = MSR_DCD;
1137 			sc->sc_ppsassert = MSR_DCD;
1138 			sc->sc_ppsclear = 0;
1139 			break;
1140 
1141 		default:
1142 			error = EINVAL;
1143 			break;
1144 		}
1145 		break;
1146 	}
1147 
1148 	case PPS_IOC_GETCAP:
1149 		*(int*)data = ppscap;
1150 		break;
1151 
1152 	case PPS_IOC_FETCH: {
1153 		pps_info_t *pi;
1154 		pi = (pps_info_t *)data;
1155 		*pi = sc->ppsinfo;
1156 		break;
1157 	}
1158 
1159 #ifdef PPS_SYNC
1160 	case PPS_IOC_KCBIND: {
1161 		int edge = (*(int *)data) & PPS_CAPTUREBOTH;
1162 
1163 		if (edge == 0) {
1164 			/*
1165 			 * remove binding for this source; ignore
1166 			 * the request if this is not the current
1167 			 * hardpps source
1168 			 */
1169 			if (pps_kc_hardpps_source == sc) {
1170 				pps_kc_hardpps_source = NULL;
1171 				pps_kc_hardpps_mode = 0;
1172 			}
1173 		} else {
1174 			/*
1175 			 * bind hardpps to this source, replacing any
1176 			 * previously specified source or edges
1177 			 */
1178 			pps_kc_hardpps_source = sc;
1179 			pps_kc_hardpps_mode = edge;
1180 		}
1181 		break;
1182 	}
1183 #endif /* PPS_SYNC */
1184 
1185 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
1186 		/*
1187 		 * Some GPS clocks models use the falling rather than
1188 		 * rising edge as the on-the-second signal.
1189 		 * The old API has no way to specify PPS polarity.
1190 		 */
1191 		sc->sc_ppsmask = MSR_DCD;
1192 #ifndef PPS_TRAILING_EDGE
1193 		sc->sc_ppsassert = MSR_DCD;
1194 		sc->sc_ppsclear = -1;
1195 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1196 		    &sc->ppsinfo.assert_timestamp);
1197 #else
1198 		sc->sc_ppsassert = -1;
1199 		sc->sc_ppsclear = 0;
1200 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1201 		    &sc->ppsinfo.clear_timestamp);
1202 #endif
1203 		break;
1204 
1205 	default:
1206 		error = EPASSTHROUGH;
1207 		break;
1208 	}
1209 
1210 	COM_UNLOCK(sc);
1211 	splx(s);
1212 
1213 #ifdef COM_DEBUG
1214 	if (com_debug)
1215 		comstatus(sc, "comioctl ");
1216 #endif
1217 
1218 	return (error);
1219 }
1220 
1221 integrate void
1222 com_schedrx(struct com_softc *sc)
1223 {
1224 
1225 	sc->sc_rx_ready = 1;
1226 
1227 	/* Wake up the poller. */
1228 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
1229 	softintr_schedule(sc->sc_si);
1230 #else
1231 #ifndef __NO_SOFT_SERIAL_INTERRUPT
1232 	setsoftserial();
1233 #else
1234 	if (!com_softintr_scheduled) {
1235 		com_softintr_scheduled = 1;
1236 		callout_reset(&comsoft_callout, 1, comsoft, NULL);
1237 	}
1238 #endif
1239 #endif
1240 }
1241 
1242 void
1243 com_break(struct com_softc *sc, int onoff)
1244 {
1245 
1246 	if (onoff)
1247 		SET(sc->sc_lcr, LCR_SBREAK);
1248 	else
1249 		CLR(sc->sc_lcr, LCR_SBREAK);
1250 
1251 	if (!sc->sc_heldchange) {
1252 		if (sc->sc_tx_busy) {
1253 			sc->sc_heldtbc = sc->sc_tbc;
1254 			sc->sc_tbc = 0;
1255 			sc->sc_heldchange = 1;
1256 		} else
1257 			com_loadchannelregs(sc);
1258 	}
1259 }
1260 
1261 void
1262 com_modem(struct com_softc *sc, int onoff)
1263 {
1264 
1265 	if (sc->sc_mcr_dtr == 0)
1266 		return;
1267 
1268 	if (onoff)
1269 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1270 	else
1271 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1272 
1273 	if (!sc->sc_heldchange) {
1274 		if (sc->sc_tx_busy) {
1275 			sc->sc_heldtbc = sc->sc_tbc;
1276 			sc->sc_tbc = 0;
1277 			sc->sc_heldchange = 1;
1278 		} else
1279 			com_loadchannelregs(sc);
1280 	}
1281 }
1282 
1283 void
1284 tiocm_to_com(struct com_softc *sc, u_long how, int ttybits)
1285 {
1286 	u_char combits;
1287 
1288 	combits = 0;
1289 	if (ISSET(ttybits, TIOCM_DTR))
1290 		SET(combits, MCR_DTR);
1291 	if (ISSET(ttybits, TIOCM_RTS))
1292 		SET(combits, MCR_RTS);
1293 
1294 	switch (how) {
1295 	case TIOCMBIC:
1296 		CLR(sc->sc_mcr, combits);
1297 		break;
1298 
1299 	case TIOCMBIS:
1300 		SET(sc->sc_mcr, combits);
1301 		break;
1302 
1303 	case TIOCMSET:
1304 		CLR(sc->sc_mcr, MCR_DTR | MCR_RTS);
1305 		SET(sc->sc_mcr, combits);
1306 		break;
1307 	}
1308 
1309 	if (!sc->sc_heldchange) {
1310 		if (sc->sc_tx_busy) {
1311 			sc->sc_heldtbc = sc->sc_tbc;
1312 			sc->sc_tbc = 0;
1313 			sc->sc_heldchange = 1;
1314 		} else
1315 			com_loadchannelregs(sc);
1316 	}
1317 }
1318 
1319 int
1320 com_to_tiocm(struct com_softc *sc)
1321 {
1322 	u_char combits;
1323 	int ttybits = 0;
1324 
1325 	combits = sc->sc_mcr;
1326 	if (ISSET(combits, MCR_DTR))
1327 		SET(ttybits, TIOCM_DTR);
1328 	if (ISSET(combits, MCR_RTS))
1329 		SET(ttybits, TIOCM_RTS);
1330 
1331 	combits = sc->sc_msr;
1332 	if (ISSET(combits, MSR_DCD))
1333 		SET(ttybits, TIOCM_CD);
1334 	if (ISSET(combits, MSR_CTS))
1335 		SET(ttybits, TIOCM_CTS);
1336 	if (ISSET(combits, MSR_DSR))
1337 		SET(ttybits, TIOCM_DSR);
1338 	if (ISSET(combits, MSR_RI | MSR_TERI))
1339 		SET(ttybits, TIOCM_RI);
1340 
1341 	if (ISSET(sc->sc_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS | IER_EMSC))
1342 		SET(ttybits, TIOCM_LE);
1343 
1344 	return (ttybits);
1345 }
1346 
1347 static u_char
1348 cflag2lcr(tcflag_t cflag)
1349 {
1350 	u_char lcr = 0;
1351 
1352 	switch (ISSET(cflag, CSIZE)) {
1353 	case CS5:
1354 		SET(lcr, LCR_5BITS);
1355 		break;
1356 	case CS6:
1357 		SET(lcr, LCR_6BITS);
1358 		break;
1359 	case CS7:
1360 		SET(lcr, LCR_7BITS);
1361 		break;
1362 	case CS8:
1363 		SET(lcr, LCR_8BITS);
1364 		break;
1365 	}
1366 	if (ISSET(cflag, PARENB)) {
1367 		SET(lcr, LCR_PENAB);
1368 		if (!ISSET(cflag, PARODD))
1369 			SET(lcr, LCR_PEVEN);
1370 	}
1371 	if (ISSET(cflag, CSTOPB))
1372 		SET(lcr, LCR_STOPB);
1373 
1374 	return (lcr);
1375 }
1376 
1377 int
1378 comparam(struct tty *tp, struct termios *t)
1379 {
1380 	struct com_softc *sc = device_lookup(&com_cd, COMUNIT(tp->t_dev));
1381 	int ospeed;
1382 	u_char lcr;
1383 	int s;
1384 
1385 	if (COM_ISALIVE(sc) == 0)
1386 		return (EIO);
1387 
1388 #ifdef COM_HAYESP
1389 	if (sc->sc_type == COM_TYPE_HAYESP) {
1390 		int prescaler, speed;
1391 
1392 		/*
1393 		 * Calculate UART clock prescaler.  It should be in
1394 		 * range of 0 .. 3.
1395 		 */
1396 		for (prescaler = 0, speed = t->c_ospeed; prescaler < 4;
1397 		    prescaler++, speed /= 2)
1398 			if ((ospeed = comspeed(speed, sc->sc_frequency,
1399 					       sc->sc_type)) > 0)
1400 				break;
1401 
1402 		if (prescaler == 4)
1403 			return (EINVAL);
1404 		sc->sc_prescaler = prescaler;
1405 	} else
1406 #endif
1407 	ospeed = comspeed(t->c_ospeed, sc->sc_frequency, sc->sc_type);
1408 
1409 	/* Check requested parameters. */
1410 	if (ospeed < 0)
1411 		return (EINVAL);
1412 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
1413 		return (EINVAL);
1414 
1415 	/*
1416 	 * For the console, always force CLOCAL and !HUPCL, so that the port
1417 	 * is always active.
1418 	 */
1419 	if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
1420 	    ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
1421 		SET(t->c_cflag, CLOCAL);
1422 		CLR(t->c_cflag, HUPCL);
1423 	}
1424 
1425 	/*
1426 	 * If there were no changes, don't do anything.  This avoids dropping
1427 	 * input and improves performance when all we did was frob things like
1428 	 * VMIN and VTIME.
1429 	 */
1430 	if (tp->t_ospeed == t->c_ospeed &&
1431 	    tp->t_cflag == t->c_cflag)
1432 		return (0);
1433 
1434 	lcr = ISSET(sc->sc_lcr, LCR_SBREAK) | cflag2lcr(t->c_cflag);
1435 
1436 	s = splserial();
1437 	COM_LOCK(sc);
1438 
1439 	sc->sc_lcr = lcr;
1440 
1441 	/*
1442 	 * If we're not in a mode that assumes a connection is present, then
1443 	 * ignore carrier changes.
1444 	 */
1445 	if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
1446 		sc->sc_msr_dcd = 0;
1447 	else
1448 		sc->sc_msr_dcd = MSR_DCD;
1449 	/*
1450 	 * Set the flow control pins depending on the current flow control
1451 	 * mode.
1452 	 */
1453 	if (ISSET(t->c_cflag, CRTSCTS)) {
1454 		sc->sc_mcr_dtr = MCR_DTR;
1455 		sc->sc_mcr_rts = MCR_RTS;
1456 		sc->sc_msr_cts = MSR_CTS;
1457 		sc->sc_efr = EFR_AUTORTS | EFR_AUTOCTS;
1458 	} else if (ISSET(t->c_cflag, MDMBUF)) {
1459 		/*
1460 		 * For DTR/DCD flow control, make sure we don't toggle DTR for
1461 		 * carrier detection.
1462 		 */
1463 		sc->sc_mcr_dtr = 0;
1464 		sc->sc_mcr_rts = MCR_DTR;
1465 		sc->sc_msr_cts = MSR_DCD;
1466 		sc->sc_efr = 0;
1467 	} else {
1468 		/*
1469 		 * If no flow control, then always set RTS.  This will make
1470 		 * the other side happy if it mistakenly thinks we're doing
1471 		 * RTS/CTS flow control.
1472 		 */
1473 		sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
1474 		sc->sc_mcr_rts = 0;
1475 		sc->sc_msr_cts = 0;
1476 		sc->sc_efr = 0;
1477 		if (ISSET(sc->sc_mcr, MCR_DTR))
1478 			SET(sc->sc_mcr, MCR_RTS);
1479 		else
1480 			CLR(sc->sc_mcr, MCR_RTS);
1481 	}
1482 	sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;
1483 
1484 #if 0
1485 	if (ospeed == 0)
1486 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1487 	else
1488 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1489 #endif
1490 
1491 	sc->sc_dlbl = ospeed;
1492 	sc->sc_dlbh = ospeed >> 8;
1493 
1494 	/*
1495 	 * Set the FIFO threshold based on the receive speed.
1496 	 *
1497 	 *  * If it's a low speed, it's probably a mouse or some other
1498 	 *    interactive device, so set the threshold low.
1499 	 *  * If it's a high speed, trim the trigger level down to prevent
1500 	 *    overflows.
1501 	 *  * Otherwise set it a bit higher.
1502 	 */
1503 	if (sc->sc_type == COM_TYPE_HAYESP)
1504 		sc->sc_fifo = FIFO_DMA_MODE | FIFO_ENABLE | FIFO_TRIGGER_8;
1505 	else if (ISSET(sc->sc_hwflags, COM_HW_FIFO))
1506 		sc->sc_fifo = FIFO_ENABLE |
1507 		    (t->c_ospeed <= 1200 ? FIFO_TRIGGER_1 : FIFO_TRIGGER_8);
1508 	else
1509 		sc->sc_fifo = 0;
1510 
1511 	/* And copy to tty. */
1512 	tp->t_ispeed = t->c_ospeed;
1513 	tp->t_ospeed = t->c_ospeed;
1514 	tp->t_cflag = t->c_cflag;
1515 
1516 	if (!sc->sc_heldchange) {
1517 		if (sc->sc_tx_busy) {
1518 			sc->sc_heldtbc = sc->sc_tbc;
1519 			sc->sc_tbc = 0;
1520 			sc->sc_heldchange = 1;
1521 		} else
1522 			com_loadchannelregs(sc);
1523 	}
1524 
1525 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1526 		/* Disable the high water mark. */
1527 		sc->sc_r_hiwat = 0;
1528 		sc->sc_r_lowat = 0;
1529 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1530 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1531 			com_schedrx(sc);
1532 		}
1533 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
1534 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
1535 			com_hwiflow(sc);
1536 		}
1537 	} else {
1538 		sc->sc_r_hiwat = com_rbuf_hiwat;
1539 		sc->sc_r_lowat = com_rbuf_lowat;
1540 	}
1541 
1542 	COM_UNLOCK(sc);
1543 	splx(s);
1544 
1545 	/*
1546 	 * Update the tty layer's idea of the carrier bit, in case we changed
1547 	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
1548 	 * explicit request.
1549 	 */
1550 	(void) (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, MSR_DCD));
1551 
1552 #ifdef COM_DEBUG
1553 	if (com_debug)
1554 		comstatus(sc, "comparam ");
1555 #endif
1556 
1557 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1558 		if (sc->sc_tx_stopped) {
1559 			sc->sc_tx_stopped = 0;
1560 			comstart(tp);
1561 		}
1562 	}
1563 
1564 	return (0);
1565 }
1566 
1567 void
1568 com_iflush(struct com_softc *sc)
1569 {
1570 	bus_space_tag_t iot = sc->sc_iot;
1571 	bus_space_handle_t ioh = sc->sc_ioh;
1572 #ifdef DIAGNOSTIC
1573 	int reg;
1574 #endif
1575 	int timo;
1576 
1577 #ifdef DIAGNOSTIC
1578 	reg = 0xffff;
1579 #endif
1580 	timo = 50000;
1581 	/* flush any pending I/O */
1582 	while (ISSET(bus_space_read_1(iot, ioh, com_lsr), LSR_RXRDY)
1583 	    && --timo)
1584 #ifdef DIAGNOSTIC
1585 		reg =
1586 #else
1587 		    (void)
1588 #endif
1589 		    bus_space_read_1(iot, ioh, com_data);
1590 #ifdef DIAGNOSTIC
1591 	if (!timo)
1592 		printf("%s: com_iflush timeout %02x\n", sc->sc_dev.dv_xname,
1593 		       reg);
1594 #endif
1595 }
1596 
1597 void
1598 com_loadchannelregs(struct com_softc *sc)
1599 {
1600 	bus_space_tag_t iot = sc->sc_iot;
1601 	bus_space_handle_t ioh = sc->sc_ioh;
1602 
1603 	/* XXXXX necessary? */
1604 	com_iflush(sc);
1605 
1606 #ifdef COM_PXA2X0
1607 	if (sc->sc_type == COM_TYPE_PXA2x0)
1608 		bus_space_write_1(iot, ioh, com_ier, IER_EUART);
1609 	else
1610 #endif
1611 		bus_space_write_1(iot, ioh, com_ier, 0);
1612 
1613 	if (ISSET(sc->sc_hwflags, COM_HW_FLOW)) {
1614 		bus_space_write_1(iot, ioh, com_lcr, LCR_EERS);
1615 		bus_space_write_1(iot, ioh, com_efr, sc->sc_efr);
1616 	}
1617 	bus_space_write_1(iot, ioh, com_lcr, sc->sc_lcr | LCR_DLAB);
1618 	bus_space_write_1(iot, ioh, com_dlbl, sc->sc_dlbl);
1619 	bus_space_write_1(iot, ioh, com_dlbh, sc->sc_dlbh);
1620 	bus_space_write_1(iot, ioh, com_lcr, sc->sc_lcr);
1621 	bus_space_write_1(iot, ioh, com_mcr, sc->sc_mcr_active = sc->sc_mcr);
1622 	bus_space_write_1(iot, ioh, com_fifo, sc->sc_fifo);
1623 #ifdef COM_HAYESP
1624 	if (sc->sc_type == COM_TYPE_HAYESP) {
1625 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD1,
1626 		    HAYESP_SETPRESCALER);
1627 		bus_space_write_1(iot, sc->sc_hayespioh, HAYESP_CMD2,
1628 		    sc->sc_prescaler);
1629 	}
1630 #endif
1631 
1632 	bus_space_write_1(iot, ioh, com_ier, sc->sc_ier);
1633 }
1634 
1635 int
1636 comhwiflow(struct tty *tp, int block)
1637 {
1638 	struct com_softc *sc = device_lookup(&com_cd, COMUNIT(tp->t_dev));
1639 	int s;
1640 
1641 	if (COM_ISALIVE(sc) == 0)
1642 		return (0);
1643 
1644 	if (sc->sc_mcr_rts == 0)
1645 		return (0);
1646 
1647 	s = splserial();
1648 	COM_LOCK(sc);
1649 
1650 	if (block) {
1651 		if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1652 			SET(sc->sc_rx_flags, RX_TTY_BLOCKED);
1653 			com_hwiflow(sc);
1654 		}
1655 	} else {
1656 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1657 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1658 			com_schedrx(sc);
1659 		}
1660 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1661 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED);
1662 			com_hwiflow(sc);
1663 		}
1664 	}
1665 
1666 	COM_UNLOCK(sc);
1667 	splx(s);
1668 	return (1);
1669 }
1670 
1671 /*
1672  * (un)block input via hw flowcontrol
1673  */
1674 void
1675 com_hwiflow(struct com_softc *sc)
1676 {
1677 	bus_space_tag_t iot = sc->sc_iot;
1678 	bus_space_handle_t ioh = sc->sc_ioh;
1679 
1680 	if (sc->sc_mcr_rts == 0)
1681 		return;
1682 
1683 	if (ISSET(sc->sc_rx_flags, RX_ANY_BLOCK)) {
1684 		CLR(sc->sc_mcr, sc->sc_mcr_rts);
1685 		CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
1686 	} else {
1687 		SET(sc->sc_mcr, sc->sc_mcr_rts);
1688 		SET(sc->sc_mcr_active, sc->sc_mcr_rts);
1689 	}
1690 	bus_space_write_1(iot, ioh, com_mcr, sc->sc_mcr_active);
1691 }
1692 
1693 
1694 void
1695 comstart(struct tty *tp)
1696 {
1697 	struct com_softc *sc = device_lookup(&com_cd, COMUNIT(tp->t_dev));
1698 	bus_space_tag_t iot = sc->sc_iot;
1699 	bus_space_handle_t ioh = sc->sc_ioh;
1700 	int s;
1701 
1702 	if (COM_ISALIVE(sc) == 0)
1703 		return;
1704 
1705 	s = spltty();
1706 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
1707 		goto out;
1708 	if (sc->sc_tx_stopped)
1709 		goto out;
1710 
1711 	if (tp->t_outq.c_cc <= tp->t_lowat) {
1712 		if (ISSET(tp->t_state, TS_ASLEEP)) {
1713 			CLR(tp->t_state, TS_ASLEEP);
1714 			wakeup(&tp->t_outq);
1715 		}
1716 		selwakeup(&tp->t_wsel);
1717 		if (tp->t_outq.c_cc == 0)
1718 			goto out;
1719 	}
1720 
1721 	/* Grab the first contiguous region of buffer space. */
1722 	{
1723 		u_char *tba;
1724 		int tbc;
1725 
1726 		tba = tp->t_outq.c_cf;
1727 		tbc = ndqb(&tp->t_outq, 0);
1728 
1729 		(void)splserial();
1730 		COM_LOCK(sc);
1731 
1732 		sc->sc_tba = tba;
1733 		sc->sc_tbc = tbc;
1734 	}
1735 
1736 	SET(tp->t_state, TS_BUSY);
1737 	sc->sc_tx_busy = 1;
1738 
1739 	/* Enable transmit completion interrupts if necessary. */
1740 	if (!ISSET(sc->sc_ier, IER_ETXRDY)) {
1741 		SET(sc->sc_ier, IER_ETXRDY);
1742 		bus_space_write_1(iot, ioh, com_ier, sc->sc_ier);
1743 	}
1744 
1745 	/* Output the first chunk of the contiguous buffer. */
1746 	if (!ISSET(sc->sc_hwflags, COM_HW_NO_TXPRELOAD)) {
1747 		u_int n;
1748 
1749 		n = sc->sc_tbc;
1750 		if (n > sc->sc_fifolen)
1751 			n = sc->sc_fifolen;
1752 		bus_space_write_multi_1(iot, ioh, com_data, sc->sc_tba, n);
1753 		sc->sc_tbc -= n;
1754 		sc->sc_tba += n;
1755 	}
1756 
1757 	COM_UNLOCK(sc);
1758 out:
1759 	splx(s);
1760 	return;
1761 }
1762 
1763 /*
1764  * Stop output on a line.
1765  */
1766 void
1767 comstop(struct tty *tp, int flag)
1768 {
1769 	struct com_softc *sc = device_lookup(&com_cd, COMUNIT(tp->t_dev));
1770 	int s;
1771 
1772 	s = splserial();
1773 	COM_LOCK(sc);
1774 	if (ISSET(tp->t_state, TS_BUSY)) {
1775 		/* Stop transmitting at the next chunk. */
1776 		sc->sc_tbc = 0;
1777 		sc->sc_heldtbc = 0;
1778 		if (!ISSET(tp->t_state, TS_TTSTOP))
1779 			SET(tp->t_state, TS_FLUSH);
1780 	}
1781 	COM_UNLOCK(sc);
1782 	splx(s);
1783 }
1784 
1785 void
1786 comdiag(void *arg)
1787 {
1788 	struct com_softc *sc = arg;
1789 	int overflows, floods;
1790 	int s;
1791 
1792 	s = splserial();
1793 	COM_LOCK(sc);
1794 	overflows = sc->sc_overflows;
1795 	sc->sc_overflows = 0;
1796 	floods = sc->sc_floods;
1797 	sc->sc_floods = 0;
1798 	sc->sc_errors = 0;
1799 	COM_UNLOCK(sc);
1800 	splx(s);
1801 
1802 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
1803 	    sc->sc_dev.dv_xname,
1804 	    overflows, overflows == 1 ? "" : "s",
1805 	    floods, floods == 1 ? "" : "s");
1806 }
1807 
1808 integrate void
1809 com_rxsoft(struct com_softc *sc, struct tty *tp)
1810 {
1811 	int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
1812 	u_char *get, *end;
1813 	u_int cc, scc;
1814 	u_char lsr;
1815 	int code;
1816 	int s;
1817 
1818 	end = sc->sc_ebuf;
1819 	get = sc->sc_rbget;
1820 	scc = cc = com_rbuf_size - sc->sc_rbavail;
1821 
1822 	if (cc == com_rbuf_size) {
1823 		sc->sc_floods++;
1824 		if (sc->sc_errors++ == 0)
1825 			callout_reset(&sc->sc_diag_callout, 60 * hz,
1826 			    comdiag, sc);
1827 	}
1828 
1829 	/* If not yet open, drop the entire buffer content here */
1830 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
1831 		get += cc << 1;
1832 		if (get >= end)
1833 			get -= com_rbuf_size << 1;
1834 		cc = 0;
1835 	}
1836 	while (cc) {
1837 		code = get[0];
1838 		lsr = get[1];
1839 		if (ISSET(lsr, LSR_OE | LSR_BI | LSR_FE | LSR_PE)) {
1840 			if (ISSET(lsr, LSR_OE)) {
1841 				sc->sc_overflows++;
1842 				if (sc->sc_errors++ == 0)
1843 					callout_reset(&sc->sc_diag_callout,
1844 					    60 * hz, comdiag, sc);
1845 			}
1846 			if (ISSET(lsr, LSR_BI | LSR_FE))
1847 				SET(code, TTY_FE);
1848 			if (ISSET(lsr, LSR_PE))
1849 				SET(code, TTY_PE);
1850 		}
1851 		if ((*rint)(code, tp) == -1) {
1852 			/*
1853 			 * The line discipline's buffer is out of space.
1854 			 */
1855 			if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1856 				/*
1857 				 * We're either not using flow control, or the
1858 				 * line discipline didn't tell us to block for
1859 				 * some reason.  Either way, we have no way to
1860 				 * know when there's more space available, so
1861 				 * just drop the rest of the data.
1862 				 */
1863 				get += cc << 1;
1864 				if (get >= end)
1865 					get -= com_rbuf_size << 1;
1866 				cc = 0;
1867 			} else {
1868 				/*
1869 				 * Don't schedule any more receive processing
1870 				 * until the line discipline tells us there's
1871 				 * space available (through comhwiflow()).
1872 				 * Leave the rest of the data in the input
1873 				 * buffer.
1874 				 */
1875 				SET(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1876 			}
1877 			break;
1878 		}
1879 		get += 2;
1880 		if (get >= end)
1881 			get = sc->sc_rbuf;
1882 		cc--;
1883 	}
1884 
1885 	if (cc != scc) {
1886 		sc->sc_rbget = get;
1887 		s = splserial();
1888 		COM_LOCK(sc);
1889 
1890 		cc = sc->sc_rbavail += scc - cc;
1891 		/* Buffers should be ok again, release possible block. */
1892 		if (cc >= sc->sc_r_lowat) {
1893 			if (ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
1894 				CLR(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
1895 				SET(sc->sc_ier, IER_ERXRDY);
1896 #ifdef COM_PXA2X0
1897 				if (sc->sc_type == COM_TYPE_PXA2x0)
1898 					SET(sc->sc_ier, IER_ERXTOUT);
1899 #endif
1900 				bus_space_write_1(sc->sc_iot, sc->sc_ioh,
1901 				    com_ier, sc->sc_ier);
1902 			}
1903 			if (ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED)) {
1904 				CLR(sc->sc_rx_flags, RX_IBUF_BLOCKED);
1905 				com_hwiflow(sc);
1906 			}
1907 		}
1908 		COM_UNLOCK(sc);
1909 		splx(s);
1910 	}
1911 }
1912 
1913 integrate void
1914 com_txsoft(struct com_softc *sc, struct tty *tp)
1915 {
1916 
1917 	CLR(tp->t_state, TS_BUSY);
1918 	if (ISSET(tp->t_state, TS_FLUSH))
1919 		CLR(tp->t_state, TS_FLUSH);
1920 	else
1921 		ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
1922 	(*tp->t_linesw->l_start)(tp);
1923 }
1924 
1925 integrate void
1926 com_stsoft(struct com_softc *sc, struct tty *tp)
1927 {
1928 	u_char msr, delta;
1929 	int s;
1930 
1931 	s = splserial();
1932 	COM_LOCK(sc);
1933 	msr = sc->sc_msr;
1934 	delta = sc->sc_msr_delta;
1935 	sc->sc_msr_delta = 0;
1936 	COM_UNLOCK(sc);
1937 	splx(s);
1938 
1939 	if (ISSET(delta, sc->sc_msr_dcd)) {
1940 		/*
1941 		 * Inform the tty layer that carrier detect changed.
1942 		 */
1943 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(msr, MSR_DCD));
1944 	}
1945 
1946 	if (ISSET(delta, sc->sc_msr_cts)) {
1947 		/* Block or unblock output according to flow control. */
1948 		if (ISSET(msr, sc->sc_msr_cts)) {
1949 			sc->sc_tx_stopped = 0;
1950 			(*tp->t_linesw->l_start)(tp);
1951 		} else {
1952 			sc->sc_tx_stopped = 1;
1953 		}
1954 	}
1955 
1956 #ifdef COM_DEBUG
1957 	if (com_debug)
1958 		comstatus(sc, "com_stsoft");
1959 #endif
1960 }
1961 
1962 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
1963 void
1964 comsoft(void *arg)
1965 {
1966 	struct com_softc *sc = arg;
1967 	struct tty *tp;
1968 
1969 	if (COM_ISALIVE(sc) == 0)
1970 		return;
1971 
1972 	{
1973 #else
1974 void
1975 #ifndef __NO_SOFT_SERIAL_INTERRUPT
1976 comsoft(void)
1977 #else
1978 comsoft(void *arg)
1979 #endif
1980 {
1981 	struct com_softc	*sc;
1982 	struct tty	*tp;
1983 	int	unit;
1984 #ifdef __NO_SOFT_SERIAL_INTERRUPT
1985 	int s;
1986 
1987 	s = splsoftserial();
1988 	com_softintr_scheduled = 0;
1989 #endif
1990 
1991 	for (unit = 0; unit < com_cd.cd_ndevs; unit++) {
1992 		sc = device_lookup(&com_cd, unit);
1993 		if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK))
1994 			continue;
1995 
1996 		if (COM_ISALIVE(sc) == 0)
1997 			continue;
1998 
1999 		tp = sc->sc_tty;
2000 		if (tp == NULL)
2001 			continue;
2002 		if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0)
2003 			continue;
2004 #endif
2005 		tp = sc->sc_tty;
2006 
2007 		if (sc->sc_rx_ready) {
2008 			sc->sc_rx_ready = 0;
2009 			com_rxsoft(sc, tp);
2010 		}
2011 
2012 		if (sc->sc_st_check) {
2013 			sc->sc_st_check = 0;
2014 			com_stsoft(sc, tp);
2015 		}
2016 
2017 		if (sc->sc_tx_done) {
2018 			sc->sc_tx_done = 0;
2019 			com_txsoft(sc, tp);
2020 		}
2021 	}
2022 
2023 #ifndef __HAVE_GENERIC_SOFT_INTERRUPTS
2024 #ifdef __NO_SOFT_SERIAL_INTERRUPT
2025 	splx(s);
2026 #endif
2027 #endif
2028 }
2029 
2030 #ifdef __ALIGN_BRACKET_LEVEL_FOR_CTAGS
2031 	/* there has got to be a better way to do comsoft() */
2032 }}
2033 #endif
2034 
2035 int
2036 comintr(void *arg)
2037 {
2038 	struct com_softc *sc = arg;
2039 	bus_space_tag_t iot = sc->sc_iot;
2040 	bus_space_handle_t ioh = sc->sc_ioh;
2041 	u_char *put, *end;
2042 	u_int cc;
2043 	u_char lsr, iir;
2044 
2045 	if (COM_ISALIVE(sc) == 0)
2046 		return (0);
2047 
2048 	COM_LOCK(sc);
2049 	iir = bus_space_read_1(iot, ioh, com_iir);
2050 	if (ISSET(iir, IIR_NOPEND)) {
2051 		COM_UNLOCK(sc);
2052 		return (0);
2053 	}
2054 
2055 	end = sc->sc_ebuf;
2056 	put = sc->sc_rbput;
2057 	cc = sc->sc_rbavail;
2058 
2059 again:	do {
2060 		u_char	msr, delta;
2061 
2062 		lsr = bus_space_read_1(iot, ioh, com_lsr);
2063 		if (ISSET(lsr, LSR_BI)) {
2064 			int cn_trapped = 0;
2065 
2066 			cn_check_magic(sc->sc_tty->t_dev,
2067 				       CNC_BREAK, com_cnm_state);
2068 			if (cn_trapped)
2069 				continue;
2070 #if defined(KGDB) && !defined(DDB)
2071 			if (ISSET(sc->sc_hwflags, COM_HW_KGDB)) {
2072 				kgdb_connect(1);
2073 				continue;
2074 			}
2075 #endif
2076 		}
2077 
2078 		if (ISSET(lsr, LSR_RCV_MASK) &&
2079 		    !ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
2080 			while (cc > 0) {
2081 				int cn_trapped = 0;
2082 				put[0] = bus_space_read_1(iot, ioh, com_data);
2083 				put[1] = lsr;
2084 				cn_check_magic(sc->sc_tty->t_dev,
2085 					       put[0], com_cnm_state);
2086 				if (cn_trapped)
2087 					goto next;
2088 				put += 2;
2089 				if (put >= end)
2090 					put = sc->sc_rbuf;
2091 				cc--;
2092 			next:
2093 				lsr = bus_space_read_1(iot, ioh, com_lsr);
2094 				if (!ISSET(lsr, LSR_RCV_MASK))
2095 					break;
2096 			}
2097 
2098 			/*
2099 			 * Current string of incoming characters ended because
2100 			 * no more data was available or we ran out of space.
2101 			 * Schedule a receive event if any data was received.
2102 			 * If we're out of space, turn off receive interrupts.
2103 			 */
2104 			sc->sc_rbput = put;
2105 			sc->sc_rbavail = cc;
2106 			if (!ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED))
2107 				sc->sc_rx_ready = 1;
2108 
2109 			/*
2110 			 * See if we are in danger of overflowing a buffer. If
2111 			 * so, use hardware flow control to ease the pressure.
2112 			 */
2113 			if (!ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED) &&
2114 			    cc < sc->sc_r_hiwat) {
2115 				SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
2116 				com_hwiflow(sc);
2117 			}
2118 
2119 			/*
2120 			 * If we're out of space, disable receive interrupts
2121 			 * until the queue has drained a bit.
2122 			 */
2123 			if (!cc) {
2124 				SET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
2125 #ifdef COM_PXA2X0
2126 				if (sc->sc_type == COM_TYPE_PXA2x0)
2127 					CLR(sc->sc_ier, IER_ERXRDY|IER_ERXTOUT);
2128 				else
2129 #endif
2130 					CLR(sc->sc_ier, IER_ERXRDY);
2131 				bus_space_write_1(iot, ioh, com_ier,
2132 				    sc->sc_ier);
2133 			}
2134 		} else {
2135 			if ((iir & (IIR_RXRDY|IIR_TXRDY)) == IIR_RXRDY) {
2136 				(void) bus_space_read_1(iot, ioh, com_data);
2137 				continue;
2138 			}
2139 		}
2140 
2141 		msr = bus_space_read_1(iot, ioh, com_msr);
2142 		delta = msr ^ sc->sc_msr;
2143 		sc->sc_msr = msr;
2144 		/*
2145 		 * Pulse-per-second (PSS) signals on edge of DCD?
2146 		 * Process these even if line discipline is ignoring DCD.
2147 		 */
2148 		if (delta & sc->sc_ppsmask) {
2149 			struct timeval tv;
2150 		    	if ((msr & sc->sc_ppsmask) == sc->sc_ppsassert) {
2151 				/* XXX nanotime() */
2152 				microtime(&tv);
2153 				TIMEVAL_TO_TIMESPEC(&tv,
2154 				    &sc->ppsinfo.assert_timestamp);
2155 				if (sc->ppsparam.mode & PPS_OFFSETASSERT) {
2156 					timespecadd(&sc->ppsinfo.assert_timestamp,
2157 					    &sc->ppsparam.assert_offset,
2158 						    &sc->ppsinfo.assert_timestamp);
2159 				}
2160 
2161 #ifdef PPS_SYNC
2162 				if (pps_kc_hardpps_source == sc &&
2163 				    pps_kc_hardpps_mode & PPS_CAPTUREASSERT) {
2164 					hardpps(&tv, tv.tv_usec);
2165 				}
2166 #endif
2167 				sc->ppsinfo.assert_sequence++;
2168 				sc->ppsinfo.current_mode = sc->ppsparam.mode;
2169 
2170 			} else if ((msr & sc->sc_ppsmask) == sc->sc_ppsclear) {
2171 				/* XXX nanotime() */
2172 				microtime(&tv);
2173 				TIMEVAL_TO_TIMESPEC(&tv,
2174 				    &sc->ppsinfo.clear_timestamp);
2175 				if (sc->ppsparam.mode & PPS_OFFSETCLEAR) {
2176 					timespecadd(&sc->ppsinfo.clear_timestamp,
2177 					    &sc->ppsparam.clear_offset,
2178 					    &sc->ppsinfo.clear_timestamp);
2179 				}
2180 
2181 #ifdef PPS_SYNC
2182 				if (pps_kc_hardpps_source == sc &&
2183 				    pps_kc_hardpps_mode & PPS_CAPTURECLEAR) {
2184 					hardpps(&tv, tv.tv_usec);
2185 				}
2186 #endif
2187 				sc->ppsinfo.clear_sequence++;
2188 				sc->ppsinfo.current_mode = sc->ppsparam.mode;
2189 			}
2190 		}
2191 
2192 		/*
2193 		 * Process normal status changes
2194 		 */
2195 		if (ISSET(delta, sc->sc_msr_mask)) {
2196 			SET(sc->sc_msr_delta, delta);
2197 
2198 			/*
2199 			 * Stop output immediately if we lose the output
2200 			 * flow control signal or carrier detect.
2201 			 */
2202 			if (ISSET(~msr, sc->sc_msr_mask)) {
2203 				sc->sc_tbc = 0;
2204 				sc->sc_heldtbc = 0;
2205 #ifdef COM_DEBUG
2206 				if (com_debug)
2207 					comstatus(sc, "comintr  ");
2208 #endif
2209 			}
2210 
2211 			sc->sc_st_check = 1;
2212 		}
2213 	} while (!ISSET((iir =
2214 	    bus_space_read_1(iot, ioh, com_iir)), IIR_NOPEND) &&
2215 	    /*
2216 	     * Since some device (e.g., ST16C1550) doesn't clear IIR_TXRDY
2217 	     * by IIR read, so we can't do this way: `process all interrupts,
2218 	     * then do TX if possble'.
2219 	     */
2220 	    (iir & IIR_IMASK) != IIR_TXRDY);
2221 
2222 	/*
2223 	 * Read LSR again, since there may be an interrupt between
2224 	 * the last LSR read and IIR read above.
2225 	 */
2226 	lsr = bus_space_read_1(iot, ioh, com_lsr);
2227 
2228 	/*
2229 	 * See if data can be transmitted as well.
2230 	 * Schedule tx done event if no data left
2231 	 * and tty was marked busy.
2232 	 */
2233 	if (ISSET(lsr, LSR_TXRDY)) {
2234 		/*
2235 		 * If we've delayed a parameter change, do it now, and restart
2236 		 * output.
2237 		 */
2238 		if (sc->sc_heldchange) {
2239 			com_loadchannelregs(sc);
2240 			sc->sc_heldchange = 0;
2241 			sc->sc_tbc = sc->sc_heldtbc;
2242 			sc->sc_heldtbc = 0;
2243 		}
2244 
2245 		/* Output the next chunk of the contiguous buffer, if any. */
2246 		if (sc->sc_tbc > 0) {
2247 			u_int n;
2248 
2249 			n = sc->sc_tbc;
2250 			if (n > sc->sc_fifolen)
2251 				n = sc->sc_fifolen;
2252 			bus_space_write_multi_1(iot, ioh, com_data, sc->sc_tba, n);
2253 			sc->sc_tbc -= n;
2254 			sc->sc_tba += n;
2255 		} else {
2256 			/* Disable transmit completion interrupts if necessary. */
2257 			if (ISSET(sc->sc_ier, IER_ETXRDY)) {
2258 				CLR(sc->sc_ier, IER_ETXRDY);
2259 				bus_space_write_1(iot, ioh, com_ier, sc->sc_ier);
2260 			}
2261 			if (sc->sc_tx_busy) {
2262 				sc->sc_tx_busy = 0;
2263 				sc->sc_tx_done = 1;
2264 			}
2265 		}
2266 	}
2267 
2268 	if (!ISSET((iir = bus_space_read_1(iot, ioh, com_iir)), IIR_NOPEND))
2269 		goto again;
2270 
2271 	COM_UNLOCK(sc);
2272 
2273 	/* Wake up the poller. */
2274 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
2275 	softintr_schedule(sc->sc_si);
2276 #else
2277 #ifndef __NO_SOFT_SERIAL_INTERRUPT
2278 	setsoftserial();
2279 #else
2280 	if (!com_softintr_scheduled) {
2281 		com_softintr_scheduled = 1;
2282 		callout_reset(&comsoft_callout, 1, comsoft, NULL);
2283 	}
2284 #endif
2285 #endif
2286 
2287 #if NRND > 0 && defined(RND_COM)
2288 	rnd_add_uint32(&sc->rnd_source, iir | lsr);
2289 #endif
2290 
2291 	return (1);
2292 }
2293 
2294 /*
2295  * The following functions are polled getc and putc routines, shared
2296  * by the console and kgdb glue.
2297  *
2298  * The read-ahead code is so that you can detect pending in-band
2299  * cn_magic in polled mode while doing output rather than having to
2300  * wait until the kernel decides it needs input.
2301  */
2302 
2303 #define MAX_READAHEAD	20
2304 static int com_readahead[MAX_READAHEAD];
2305 static int com_readaheadcount = 0;
2306 
2307 int
2308 com_common_getc(dev_t dev, bus_space_tag_t iot, bus_space_handle_t ioh)
2309 {
2310 	int s = splserial();
2311 	u_char stat, c;
2312 
2313 	/* got a character from reading things earlier */
2314 	if (com_readaheadcount > 0) {
2315 		int i;
2316 
2317 		c = com_readahead[0];
2318 		for (i = 1; i < com_readaheadcount; i++) {
2319 			com_readahead[i-1] = com_readahead[i];
2320 		}
2321 		com_readaheadcount--;
2322 		splx(s);
2323 		return (c);
2324 	}
2325 
2326 	/* block until a character becomes available */
2327 	while (!ISSET(stat = bus_space_read_1(iot, ioh, com_lsr), LSR_RXRDY))
2328 		;
2329 
2330 	c = bus_space_read_1(iot, ioh, com_data);
2331 	stat = bus_space_read_1(iot, ioh, com_iir);
2332 	{
2333 		int cn_trapped = 0; /* unused */
2334 #ifdef DDB
2335 		extern int db_active;
2336 		if (!db_active)
2337 #endif
2338 			cn_check_magic(dev, c, com_cnm_state);
2339 	}
2340 	splx(s);
2341 	return (c);
2342 }
2343 
2344 void
2345 com_common_putc(dev_t dev, bus_space_tag_t iot, bus_space_handle_t ioh, int c)
2346 {
2347 	int s = splserial();
2348 	int cin, stat, timo;
2349 
2350 	if (com_readaheadcount < MAX_READAHEAD
2351 	     && ISSET(stat = bus_space_read_1(iot, ioh, com_lsr), LSR_RXRDY)) {
2352 		int cn_trapped = 0;
2353 		cin = bus_space_read_1(iot, ioh, com_data);
2354 		stat = bus_space_read_1(iot, ioh, com_iir);
2355 		cn_check_magic(dev, cin, com_cnm_state);
2356 		com_readahead[com_readaheadcount++] = cin;
2357 	}
2358 
2359 	/* wait for any pending transmission to finish */
2360 	timo = 150000;
2361 	while (!ISSET(bus_space_read_1(iot, ioh, com_lsr), LSR_TXRDY) && --timo)
2362 		continue;
2363 
2364 	bus_space_write_1(iot, ioh, com_data, c);
2365 	COM_BARRIER(iot, ioh, BR | BW);
2366 
2367 	splx(s);
2368 }
2369 
2370 /*
2371  * Initialize UART for use as console or KGDB line.
2372  */
2373 int
2374 cominit(bus_space_tag_t iot, bus_addr_t iobase, int rate, int frequency,
2375     int type, tcflag_t cflag, bus_space_handle_t *iohp)
2376 {
2377 	bus_space_handle_t ioh;
2378 
2379 	if (bus_space_map(iot, iobase, COM_NPORTS, 0, &ioh))
2380 		return (ENOMEM); /* ??? */
2381 
2382 	bus_space_write_1(iot, ioh, com_lcr, LCR_EERS);
2383 	bus_space_write_1(iot, ioh, com_efr, 0);
2384 	bus_space_write_1(iot, ioh, com_lcr, LCR_DLAB);
2385 	rate = comspeed(rate, frequency, type);
2386 	bus_space_write_1(iot, ioh, com_dlbl, rate);
2387 	bus_space_write_1(iot, ioh, com_dlbh, rate >> 8);
2388 	bus_space_write_1(iot, ioh, com_lcr, cflag2lcr(cflag));
2389 	bus_space_write_1(iot, ioh, com_mcr, MCR_DTR | MCR_RTS);
2390 	bus_space_write_1(iot, ioh, com_fifo,
2391 	    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
2392 #ifdef COM_PXA2X0
2393 	if (type == COM_TYPE_PXA2x0)
2394 		bus_space_write_1(iot, ioh, com_ier, IER_EUART);
2395 	else
2396 #endif
2397 		bus_space_write_1(iot, ioh, com_ier, 0);
2398 
2399 	*iohp = ioh;
2400 	return (0);
2401 }
2402 
2403 /*
2404  * Following are all routines needed for COM to act as console
2405  */
2406 struct consdev comcons = {
2407 	NULL, NULL, comcngetc, comcnputc, comcnpollc, NULL, NULL, NULL,
2408 	NODEV, CN_NORMAL
2409 };
2410 
2411 
2412 int
2413 comcnattach(bus_space_tag_t iot, bus_addr_t iobase, int rate, int frequency,
2414     int type, tcflag_t cflag)
2415 {
2416 	int res;
2417 
2418 	res = cominit(iot, iobase, rate, frequency, type, cflag, &comconsioh);
2419 	if (res)
2420 		return (res);
2421 
2422 	cn_tab = &comcons;
2423 	cn_init_magic(&com_cnm_state);
2424 	cn_set_magic("\047\001"); /* default magic is BREAK */
2425 
2426 	comconstag = iot;
2427 	comconsaddr = iobase;
2428 	comconsrate = rate;
2429 	comconscflag = cflag;
2430 
2431 	return (0);
2432 }
2433 
2434 int
2435 comcngetc(dev_t dev)
2436 {
2437 
2438 	return (com_common_getc(dev, comconstag, comconsioh));
2439 }
2440 
2441 /*
2442  * Console kernel output character routine.
2443  */
2444 void
2445 comcnputc(dev_t dev, int c)
2446 {
2447 
2448 	com_common_putc(dev, comconstag, comconsioh, c);
2449 }
2450 
2451 void
2452 comcnpollc(dev_t dev, int on)
2453 {
2454 
2455 }
2456 
2457 #ifdef KGDB
2458 int
2459 com_kgdb_attach(bus_space_tag_t iot, bus_addr_t iobase, int rate,
2460     int frequency, int type, tcflag_t cflag)
2461 {
2462 	int res;
2463 
2464 	if (iot == comconstag && iobase == comconsaddr) {
2465 #if !defined(DDB)
2466 		return (EBUSY); /* cannot share with console */
2467 #else
2468 		com_kgdb_ioh = comconsioh;
2469 #endif
2470 	} else {
2471 		res = cominit(iot, iobase, rate, frequency, type, cflag,
2472 			      &com_kgdb_ioh);
2473 		if (res)
2474 			return (res);
2475 
2476 		/*
2477 		 * XXXfvdl this shouldn't be needed, but the cn_magic goo
2478 		 * expects this to be initialized
2479 		 */
2480 		cn_init_magic(&com_cnm_state);
2481 		cn_set_magic("\047\001");
2482 	}
2483 
2484 	kgdb_attach(com_kgdb_getc, com_kgdb_putc, NULL);
2485 	kgdb_dev = 123; /* unneeded, only to satisfy some tests */
2486 
2487 	com_kgdb_iot = iot;
2488 	com_kgdb_addr = iobase;
2489 
2490 	return (0);
2491 }
2492 
2493 /* ARGSUSED */
2494 int
2495 com_kgdb_getc(void *arg)
2496 {
2497 
2498 	return (com_common_getc(NODEV, com_kgdb_iot, com_kgdb_ioh));
2499 }
2500 
2501 /* ARGSUSED */
2502 void
2503 com_kgdb_putc(void *arg, int c)
2504 {
2505 
2506 	com_common_putc(NODEV, com_kgdb_iot, com_kgdb_ioh, c);
2507 }
2508 #endif /* KGDB */
2509 
2510 /* helper function to identify the com ports used by
2511  console or KGDB (and not yet autoconf attached) */
2512 int
2513 com_is_console(bus_space_tag_t iot, bus_addr_t iobase, bus_space_handle_t *ioh)
2514 {
2515 	bus_space_handle_t help;
2516 
2517 	if (!comconsattached &&
2518 	    iot == comconstag && iobase == comconsaddr)
2519 		help = comconsioh;
2520 #ifdef KGDB
2521 	else if (!com_kgdb_attached &&
2522 	    iot == com_kgdb_iot && iobase == com_kgdb_addr)
2523 		help = com_kgdb_ioh;
2524 #endif
2525 	else
2526 		return (0);
2527 
2528 	if (ioh)
2529 		*ioh = help;
2530 	return (1);
2531 }
2532