xref: /netbsd-src/sys/dev/ic/com.c (revision 8ac07aec990b9d2e483062509d0a9fa5b4f57cf2)
1 /*	$NetBSD: com.c,v 1.279 2008/04/21 12:56:31 ad Exp $	*/
2 
3 /*-
4  * Copyright (c) 1998, 1999, 2004, 2008 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 1.279 2008/04/21 12:56:31 ad 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 #include <sys/kauth.h>
125 #include <sys/intr.h>
126 
127 #include <sys/bus.h>
128 
129 #include <dev/ic/comreg.h>
130 #include <dev/ic/comvar.h>
131 #include <dev/ic/ns16550reg.h>
132 #include <dev/ic/st16650reg.h>
133 #ifdef COM_HAYESP
134 #include <dev/ic/hayespreg.h>
135 #endif
136 #define	com_lcr	com_cfcr
137 #include <dev/cons.h>
138 
139 #ifdef	COM_REGMAP
140 #define	CSR_WRITE_1(r, o, v)	\
141 	bus_space_write_1((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o], v)
142 #define	CSR_READ_1(r, o)	\
143 	bus_space_read_1((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o])
144 #define	CSR_WRITE_2(r, o, v)	\
145 	bus_space_write_2((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o], v)
146 #define	CSR_READ_2(r, o)	\
147 	bus_space_read_2((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o])
148 #define	CSR_WRITE_MULTI(r, o, p, n)	\
149 	bus_space_write_multi_1((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o], p, n)
150 #else
151 #define	CSR_WRITE_1(r, o, v)	\
152 	bus_space_write_1((r)->cr_iot, (r)->cr_ioh, o, v)
153 #define	CSR_READ_1(r, o)	\
154 	bus_space_read_1((r)->cr_iot, (r)->cr_ioh, o)
155 #define	CSR_WRITE_2(r, o, v)	\
156 	bus_space_write_2((r)->cr_iot, (r)->cr_ioh, o, v)
157 #define	CSR_READ_2(r, o)	\
158 	bus_space_read_2((r)->cr_iot, (r)->cr_ioh, o)
159 #define	CSR_WRITE_MULTI(r, o, p, n)	\
160 	bus_space_write_multi_1((r)->cr_iot, (r)->cr_ioh, o, p, n)
161 #endif
162 
163 
164 static void com_enable_debugport(struct com_softc *);
165 
166 void	com_config(struct com_softc *);
167 void	com_shutdown(struct com_softc *);
168 int	comspeed(long, long, int);
169 static	u_char	cflag2lcr(tcflag_t);
170 int	comparam(struct tty *, struct termios *);
171 void	comstart(struct tty *);
172 int	comhwiflow(struct tty *, int);
173 
174 void	com_loadchannelregs(struct com_softc *);
175 void	com_hwiflow(struct com_softc *);
176 void	com_break(struct com_softc *, int);
177 void	com_modem(struct com_softc *, int);
178 void	tiocm_to_com(struct com_softc *, u_long, int);
179 int	com_to_tiocm(struct com_softc *);
180 void	com_iflush(struct com_softc *);
181 
182 int	com_common_getc(dev_t, struct com_regs *);
183 void	com_common_putc(dev_t, struct com_regs *, int);
184 
185 int	cominit(struct com_regs *, int, int, int, tcflag_t);
186 
187 int	comcngetc(dev_t);
188 void	comcnputc(dev_t, int);
189 void	comcnpollc(dev_t, int);
190 
191 #define	integrate	static inline
192 void 	comsoft(void *);
193 integrate void com_rxsoft(struct com_softc *, struct tty *);
194 integrate void com_txsoft(struct com_softc *, struct tty *);
195 integrate void com_stsoft(struct com_softc *, struct tty *);
196 integrate void com_schedrx(struct com_softc *);
197 void	comdiag(void *);
198 
199 extern struct cfdriver com_cd;
200 
201 dev_type_open(comopen);
202 dev_type_close(comclose);
203 dev_type_read(comread);
204 dev_type_write(comwrite);
205 dev_type_ioctl(comioctl);
206 dev_type_stop(comstop);
207 dev_type_tty(comtty);
208 dev_type_poll(compoll);
209 
210 const struct cdevsw com_cdevsw = {
211 	comopen, comclose, comread, comwrite, comioctl,
212 	comstop, comtty, compoll, nommap, ttykqfilter, D_TTY
213 };
214 
215 /*
216  * Make this an option variable one can patch.
217  * But be warned:  this must be a power of 2!
218  */
219 u_int com_rbuf_size = COM_RING_SIZE;
220 
221 /* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
222 u_int com_rbuf_hiwat = (COM_RING_SIZE * 1) / 4;
223 u_int com_rbuf_lowat = (COM_RING_SIZE * 3) / 4;
224 
225 static struct com_regs comconsregs;
226 static int comconsattached;
227 static int comconsrate;
228 static tcflag_t comconscflag;
229 static struct cnm_state com_cnm_state;
230 
231 #ifdef KGDB
232 #include <sys/kgdb.h>
233 
234 static struct com_regs comkgdbregs;
235 static int com_kgdb_attached;
236 
237 int	com_kgdb_getc(void *);
238 void	com_kgdb_putc(void *, int);
239 #endif /* KGDB */
240 
241 #ifdef COM_REGMAP
242 /* initializer for typical 16550-ish hardware */
243 #define	COM_REG_16550	{ \
244 	com_data, com_data, com_dlbl, com_dlbh, com_ier, com_iir, com_fifo, \
245 	com_efr, com_lcr, com_mcr, com_lsr, com_msr }
246 
247 const bus_size_t com_std_map[16] = COM_REG_16550;
248 #endif /* COM_REGMAP */
249 
250 #define	COMUNIT_MASK	0x7ffff
251 #define	COMDIALOUT_MASK	0x80000
252 
253 #define	COMUNIT(x)	(minor(x) & COMUNIT_MASK)
254 #define	COMDIALOUT(x)	(minor(x) & COMDIALOUT_MASK)
255 
256 #define	COM_ISALIVE(sc)	((sc)->enabled != 0 && \
257 			 device_is_active((sc)->sc_dev))
258 
259 #define	BR	BUS_SPACE_BARRIER_READ
260 #define	BW	BUS_SPACE_BARRIER_WRITE
261 #define COM_BARRIER(r, f) \
262 	bus_space_barrier((r)->cr_iot, (r)->cr_ioh, 0, (r)->cr_nports, (f))
263 
264 /*ARGSUSED*/
265 int
266 comspeed(long speed, long frequency, int type)
267 {
268 #define	divrnd(n, q)	(((n)*2/(q)+1)/2)	/* divide and round off */
269 
270 	int x, err;
271 
272 #if 0
273 	if (speed == 0)
274 		return (0);
275 #endif
276 	if (speed <= 0)
277 		return (-1);
278 	x = divrnd(frequency / 16, speed);
279 	if (x <= 0)
280 		return (-1);
281 	err = divrnd(((quad_t)frequency) * 1000 / 16, speed * x) - 1000;
282 	if (err < 0)
283 		err = -err;
284 	if (err > COM_TOLERANCE)
285 		return (-1);
286 	return (x);
287 
288 #undef	divrnd
289 }
290 
291 #ifdef COM_DEBUG
292 int	com_debug = 0;
293 
294 void comstatus(struct com_softc *, const char *);
295 void
296 comstatus(struct com_softc *sc, const char *str)
297 {
298 	struct tty *tp = sc->sc_tty;
299 
300 	aprint_normal_dev(sc->sc_dev,
301 	    "%s %cclocal  %cdcd %cts_carr_on %cdtr %ctx_stopped\n",
302 	    str,
303 	    ISSET(tp->t_cflag, CLOCAL) ? '+' : '-',
304 	    ISSET(sc->sc_msr, MSR_DCD) ? '+' : '-',
305 	    ISSET(tp->t_state, TS_CARR_ON) ? '+' : '-',
306 	    ISSET(sc->sc_mcr, MCR_DTR) ? '+' : '-',
307 	    sc->sc_tx_stopped ? '+' : '-');
308 
309 	aprint_normal_dev(sc->sc_dev,
310 	    "%s %ccrtscts %ccts %cts_ttstop  %crts rx_flags=0x%x\n",
311 	    str,
312 	    ISSET(tp->t_cflag, CRTSCTS) ? '+' : '-',
313 	    ISSET(sc->sc_msr, MSR_CTS) ? '+' : '-',
314 	    ISSET(tp->t_state, TS_TTSTOP) ? '+' : '-',
315 	    ISSET(sc->sc_mcr, MCR_RTS) ? '+' : '-',
316 	    sc->sc_rx_flags);
317 }
318 #endif
319 
320 int
321 com_probe_subr(struct com_regs *regs)
322 {
323 
324 	/* force access to id reg */
325 	CSR_WRITE_1(regs, COM_REG_LCR, LCR_8BITS);
326 	CSR_WRITE_1(regs, COM_REG_IIR, 0);
327 	if ((CSR_READ_1(regs, COM_REG_LCR) != LCR_8BITS) ||
328 	    (CSR_READ_1(regs, COM_REG_IIR) & 0x38))
329 		return (0);
330 
331 	return (1);
332 }
333 
334 int
335 comprobe1(bus_space_tag_t iot, bus_space_handle_t ioh)
336 {
337 	struct com_regs	regs;
338 
339 	regs.cr_iot = iot;
340 	regs.cr_ioh = ioh;
341 #ifdef	COM_REGMAP
342 	memcpy(regs.cr_map, com_std_map, sizeof (regs.cr_map));;
343 #endif
344 
345 	return com_probe_subr(&regs);
346 }
347 
348 /*
349  * No locking in this routine; it is only called during attach,
350  * or with the port already locked.
351  */
352 static void
353 com_enable_debugport(struct com_softc *sc)
354 {
355 
356 	/* Turn on line break interrupt, set carrier. */
357 	sc->sc_ier = IER_ERXRDY;
358 	if (sc->sc_type == COM_TYPE_PXA2x0)
359 		sc->sc_ier |= IER_EUART | IER_ERXTOUT;
360 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
361 	SET(sc->sc_mcr, MCR_DTR | MCR_RTS);
362 	CSR_WRITE_1(&sc->sc_regs, COM_REG_MCR, sc->sc_mcr);
363 }
364 
365 void
366 com_attach_subr(struct com_softc *sc)
367 {
368 	struct com_regs *regsp = &sc->sc_regs;
369 	struct tty *tp;
370 #ifdef COM_16650
371 	u_int8_t lcr;
372 #endif
373 	const char *fifo_msg = NULL;
374 
375 	aprint_naive("\n");
376 
377 	callout_init(&sc->sc_diag_callout, 0);
378 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_HIGH);
379 
380 	/* Disable interrupts before configuring the device. */
381 	if (sc->sc_type == COM_TYPE_PXA2x0)
382 		sc->sc_ier = IER_EUART;
383 	else
384 		sc->sc_ier = 0;
385 
386 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
387 
388 	if (regsp->cr_iot == comconsregs.cr_iot &&
389 	    regsp->cr_iobase == comconsregs.cr_iobase) {
390 		comconsattached = 1;
391 
392 		/* Make sure the console is always "hardwired". */
393 		delay(10000);			/* wait for output to finish */
394 		SET(sc->sc_hwflags, COM_HW_CONSOLE);
395 		SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
396 	}
397 
398 	/* Probe for FIFO */
399 	switch (sc->sc_type) {
400 	case COM_TYPE_HAYESP:
401 		goto fifodone;
402 
403 	case COM_TYPE_AU1x00:
404 		sc->sc_fifolen = 16;
405 		fifo_msg = "Au1X00 UART, working fifo";
406 		SET(sc->sc_hwflags, COM_HW_FIFO);
407 		goto fifodelay;
408 	}
409 
410 	sc->sc_fifolen = 1;
411 	/* look for a NS 16550AF UART with FIFOs */
412 	CSR_WRITE_1(regsp, COM_REG_FIFO,
413 	    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_14);
414 	delay(100);
415 	if (ISSET(CSR_READ_1(regsp, COM_REG_IIR), IIR_FIFO_MASK)
416 	    == IIR_FIFO_MASK)
417 		if (ISSET(CSR_READ_1(regsp, COM_REG_FIFO), FIFO_TRIGGER_14)
418 		    == FIFO_TRIGGER_14) {
419 			SET(sc->sc_hwflags, COM_HW_FIFO);
420 
421 #ifdef COM_16650
422 			/*
423 			 * IIR changes into the EFR if LCR is set to LCR_EERS
424 			 * on 16650s. We also know IIR != 0 at this point.
425 			 * Write 0 into the EFR, and read it. If the result
426 			 * is 0, we have a 16650.
427 			 *
428 			 * Older 16650s were broken; the test to detect them
429 			 * is taken from the Linux driver. Apparently
430 			 * setting DLAB enable gives access to the EFR on
431 			 * these chips.
432 			 */
433 			lcr = CSR_READ_1(regsp, COM_REG_LCR);
434 			CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
435 			CSR_WRITE_1(regsp, COM_REG_EFR, 0);
436 			if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
437 				CSR_WRITE_1(regsp, COM_REG_LCR,
438 				    lcr | LCR_DLAB);
439 				if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
440 					CLR(sc->sc_hwflags, COM_HW_FIFO);
441 					sc->sc_fifolen = 0;
442 				} else {
443 					SET(sc->sc_hwflags, COM_HW_FLOW);
444 					sc->sc_fifolen = 32;
445 				}
446 			} else
447 #endif
448 				sc->sc_fifolen = 16;
449 
450 #ifdef COM_16650
451 			CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
452 			if (sc->sc_fifolen == 0)
453 				fifo_msg = "st16650, broken fifo";
454 			else if (sc->sc_fifolen == 32)
455 				fifo_msg = "st16650a, working fifo";
456 			else
457 #endif
458 				fifo_msg = "ns16550a, working fifo";
459 		} else
460 			fifo_msg = "ns16550, broken fifo";
461 	else
462 		fifo_msg = "ns8250 or ns16450, no fifo";
463 	CSR_WRITE_1(regsp, COM_REG_FIFO, 0);
464 fifodelay:
465 	/*
466 	 * Some chips will clear down both Tx and Rx FIFOs when zero is
467 	 * written to com_fifo. If this chip is the console, writing zero
468 	 * results in some of the chip/FIFO description being lost, so delay
469 	 * printing it until now.
470 	 */
471 	delay(10);
472 	aprint_normal(": %s\n", fifo_msg);
473 	if (ISSET(sc->sc_hwflags, COM_HW_TXFIFO_DISABLE)) {
474 		sc->sc_fifolen = 1;
475 		aprint_normal_dev(sc->sc_dev, "txfifo disabled\n");
476 	}
477 
478 fifodone:
479 
480 	tp = ttymalloc();
481 	tp->t_oproc = comstart;
482 	tp->t_param = comparam;
483 	tp->t_hwiflow = comhwiflow;
484 
485 	sc->sc_tty = tp;
486 	sc->sc_rbuf = malloc(com_rbuf_size << 1, M_DEVBUF, M_NOWAIT);
487 	sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
488 	sc->sc_rbavail = com_rbuf_size;
489 	if (sc->sc_rbuf == NULL) {
490 		aprint_error_dev(sc->sc_dev,
491 		    "unable to allocate ring buffer\n");
492 		return;
493 	}
494 	sc->sc_ebuf = sc->sc_rbuf + (com_rbuf_size << 1);
495 
496 	tty_attach(tp);
497 
498 	if (!ISSET(sc->sc_hwflags, COM_HW_NOIEN))
499 		SET(sc->sc_mcr, MCR_IENABLE);
500 
501 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
502 		int maj;
503 
504 		/* locate the major number */
505 		maj = cdevsw_lookup_major(&com_cdevsw);
506 
507 		tp->t_dev = cn_tab->cn_dev = makedev(maj,
508 						     device_unit(sc->sc_dev));
509 
510 		aprint_normal_dev(sc->sc_dev, "console\n");
511 	}
512 
513 #ifdef KGDB
514 	/*
515 	 * Allow kgdb to "take over" this port.  If this is
516 	 * not the console and is the kgdb device, it has
517 	 * exclusive use.  If it's the console _and_ the
518 	 * kgdb device, it doesn't.
519 	 */
520 	if (regsp->cr_iot == comkgdbregs.cr_iot &&
521 	    regsp->cr_iobase == comkgdbregs.cr_iobase) {
522 		if (!ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
523 			com_kgdb_attached = 1;
524 
525 			SET(sc->sc_hwflags, COM_HW_KGDB);
526 		}
527 		aprint_normal_dev(sc->sc_dev, "kgdb\n");
528 	}
529 #endif
530 
531 	sc->sc_si = softint_establish(SOFTINT_SERIAL, comsoft, sc);
532 
533 #if NRND > 0 && defined(RND_COM)
534 	rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
535 			  RND_TYPE_TTY, 0);
536 #endif
537 
538 	/* if there are no enable/disable functions, assume the device
539 	   is always enabled */
540 	if (!sc->enable)
541 		sc->enabled = 1;
542 
543 	com_config(sc);
544 
545 	SET(sc->sc_hwflags, COM_HW_DEV_OK);
546 }
547 
548 void
549 com_config(struct com_softc *sc)
550 {
551 	struct com_regs *regsp = &sc->sc_regs;
552 
553 	/* Disable interrupts before configuring the device. */
554 	if (sc->sc_type == COM_TYPE_PXA2x0)
555 		sc->sc_ier = IER_EUART;
556 	else
557 		sc->sc_ier = 0;
558 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
559 	(void) CSR_READ_1(regsp, COM_REG_IIR);
560 
561 #ifdef COM_HAYESP
562 	/* Look for a Hayes ESP board. */
563 	if (sc->sc_type == COM_TYPE_HAYESP) {
564 
565 		/* Set 16550 compatibility mode */
566 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
567 				  HAYESP_SETMODE);
568 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
569 				  HAYESP_MODE_FIFO|HAYESP_MODE_RTS|
570 				  HAYESP_MODE_SCALE);
571 
572 		/* Set RTS/CTS flow control */
573 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
574 				  HAYESP_SETFLOWTYPE);
575 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
576 				  HAYESP_FLOW_RTS);
577 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
578 				  HAYESP_FLOW_CTS);
579 
580 		/* Set flow control levels */
581 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
582 				  HAYESP_SETRXFLOW);
583 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
584 				  HAYESP_HIBYTE(HAYESP_RXHIWMARK));
585 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
586 				  HAYESP_LOBYTE(HAYESP_RXHIWMARK));
587 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
588 				  HAYESP_HIBYTE(HAYESP_RXLOWMARK));
589 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
590 				  HAYESP_LOBYTE(HAYESP_RXLOWMARK));
591 	}
592 #endif
593 
594 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE|COM_HW_KGDB))
595 		com_enable_debugport(sc);
596 }
597 
598 int
599 com_detach(device_t self, int flags)
600 {
601 	struct com_softc *sc = device_private(self);
602 	int maj, mn;
603 
604         if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE))
605 		return EBUSY;
606 
607 	/* locate the major number */
608 	maj = cdevsw_lookup_major(&com_cdevsw);
609 
610 	/* Nuke the vnodes for any open instances. */
611 	mn = device_unit(self);
612 	vdevgone(maj, mn, mn, VCHR);
613 
614 	mn |= COMDIALOUT_MASK;
615 	vdevgone(maj, mn, mn, VCHR);
616 
617 	if (sc->sc_rbuf == NULL) {
618 		/*
619 		 * Ring buffer allocation failed in the com_attach_subr,
620 		 * only the tty is allocated, and nothing else.
621 		 */
622 		ttyfree(sc->sc_tty);
623 		return 0;
624 	}
625 
626 	/* Free the receive buffer. */
627 	free(sc->sc_rbuf, M_DEVBUF);
628 
629 	/* Detach and free the tty. */
630 	tty_detach(sc->sc_tty);
631 	ttyfree(sc->sc_tty);
632 
633 	/* Unhook the soft interrupt handler. */
634 	softint_disestablish(sc->sc_si);
635 
636 #if NRND > 0 && defined(RND_COM)
637 	/* Unhook the entropy source. */
638 	rnd_detach_source(&sc->rnd_source);
639 #endif
640 	callout_destroy(&sc->sc_diag_callout);
641 
642 	/* Destroy the lock. */
643 	mutex_destroy(&sc->sc_lock);
644 
645 	return (0);
646 }
647 
648 int
649 com_activate(device_t self, enum devact act)
650 {
651 	struct com_softc *sc = device_private(self);
652 	int rv = 0;
653 
654 	switch (act) {
655 	case DVACT_ACTIVATE:
656 		rv = EOPNOTSUPP;
657 		break;
658 
659 	case DVACT_DEACTIVATE:
660 		if (sc->sc_hwflags & (COM_HW_CONSOLE|COM_HW_KGDB)) {
661 			rv = EBUSY;
662 			break;
663 		}
664 
665 		if (sc->disable != NULL && sc->enabled != 0) {
666 			(*sc->disable)(sc);
667 			sc->enabled = 0;
668 		}
669 		break;
670 	}
671 
672 	return (rv);
673 }
674 
675 void
676 com_shutdown(struct com_softc *sc)
677 {
678 	struct tty *tp = sc->sc_tty;
679 
680 	mutex_spin_enter(&sc->sc_lock);
681 
682 	/* If we were asserting flow control, then deassert it. */
683 	SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
684 	com_hwiflow(sc);
685 
686 	/* Clear any break condition set with TIOCSBRK. */
687 	com_break(sc, 0);
688 
689 	/*
690 	 * Hang up if necessary.  Wait a bit, so the other side has time to
691 	 * notice even if we immediately open the port again.
692 	 * Avoid tsleeping above splhigh().
693 	 */
694 	if (ISSET(tp->t_cflag, HUPCL)) {
695 		com_modem(sc, 0);
696 		mutex_spin_exit(&sc->sc_lock);
697 		/* XXX will only timeout */
698 		(void) kpause(ttclos, false, hz, NULL);
699 		mutex_spin_enter(&sc->sc_lock);
700 	}
701 
702 	/* Turn off interrupts. */
703 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
704 		sc->sc_ier = IER_ERXRDY; /* interrupt on break */
705 		if (sc->sc_type == COM_TYPE_PXA2x0)
706 			sc->sc_ier |= IER_ERXTOUT;
707 	} else
708 		sc->sc_ier = 0;
709 
710 	if (sc->sc_type == COM_TYPE_PXA2x0)
711 		sc->sc_ier |= IER_EUART;
712 
713 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
714 
715 	mutex_spin_exit(&sc->sc_lock);
716 
717 	if (sc->disable) {
718 #ifdef DIAGNOSTIC
719 		if (!sc->enabled)
720 			panic("com_shutdown: not enabled?");
721 #endif
722 		(*sc->disable)(sc);
723 		sc->enabled = 0;
724 	}
725 }
726 
727 int
728 comopen(dev_t dev, int flag, int mode, struct lwp *l)
729 {
730 	struct com_softc *sc;
731 	struct tty *tp;
732 	int s;
733 	int error;
734 
735 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
736 	if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK) ||
737 		sc->sc_rbuf == NULL)
738 		return (ENXIO);
739 
740 	if (!device_is_active(sc->sc_dev))
741 		return (ENXIO);
742 
743 #ifdef KGDB
744 	/*
745 	 * If this is the kgdb port, no other use is permitted.
746 	 */
747 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
748 		return (EBUSY);
749 #endif
750 
751 	tp = sc->sc_tty;
752 
753 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
754 		return (EBUSY);
755 
756 	s = spltty();
757 
758 	/*
759 	 * Do the following iff this is a first open.
760 	 */
761 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
762 		struct termios t;
763 
764 		tp->t_dev = dev;
765 
766 
767 		if (sc->enable) {
768 			if ((*sc->enable)(sc)) {
769 				splx(s);
770 				aprint_error_dev(sc->sc_dev,
771 				    "device enable failed\n");
772 				return (EIO);
773 			}
774 			mutex_spin_enter(&sc->sc_lock);
775 			sc->enabled = 1;
776 			com_config(sc);
777 		} else {
778 			mutex_spin_enter(&sc->sc_lock);
779 		}
780 
781 		/* Turn on interrupts. */
782 		sc->sc_ier = IER_ERXRDY | IER_ERLS | IER_EMSC;
783 		if (sc->sc_type == COM_TYPE_PXA2x0)
784 			sc->sc_ier |= IER_EUART | IER_ERXTOUT;
785 		CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
786 
787 		/* Fetch the current modem control status, needed later. */
788 		sc->sc_msr = CSR_READ_1(&sc->sc_regs, COM_REG_MSR);
789 
790 		/* Clear PPS capture state on first open. */
791 		mutex_spin_enter(&timecounter_lock);
792 		memset(&sc->sc_pps_state, 0, sizeof(sc->sc_pps_state));
793 		sc->sc_pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
794 		pps_init(&sc->sc_pps_state);
795 		mutex_spin_exit(&timecounter_lock);
796 
797 		mutex_spin_exit(&sc->sc_lock);
798 
799 		/*
800 		 * Initialize the termios status to the defaults.  Add in the
801 		 * sticky bits from TIOCSFLAGS.
802 		 */
803 		if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
804 			t.c_ospeed = comconsrate;
805 			t.c_cflag = comconscflag;
806 		} else {
807 			t.c_ospeed = TTYDEF_SPEED;
808 			t.c_cflag = TTYDEF_CFLAG;
809 		}
810 		t.c_ispeed = t.c_ospeed;
811 		if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
812 			SET(t.c_cflag, CLOCAL);
813 		if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
814 			SET(t.c_cflag, CRTSCTS);
815 		if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
816 			SET(t.c_cflag, MDMBUF);
817 		/* Make sure comparam() will do something. */
818 		tp->t_ospeed = 0;
819 		(void) comparam(tp, &t);
820 		tp->t_iflag = TTYDEF_IFLAG;
821 		tp->t_oflag = TTYDEF_OFLAG;
822 		tp->t_lflag = TTYDEF_LFLAG;
823 		ttychars(tp);
824 		ttsetwater(tp);
825 
826 		mutex_spin_enter(&sc->sc_lock);
827 
828 		/*
829 		 * Turn on DTR.  We must always do this, even if carrier is not
830 		 * present, because otherwise we'd have to use TIOCSDTR
831 		 * immediately after setting CLOCAL, which applications do not
832 		 * expect.  We always assert DTR while the device is open
833 		 * unless explicitly requested to deassert it.
834 		 */
835 		com_modem(sc, 1);
836 
837 		/* Clear the input ring, and unblock. */
838 		sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
839 		sc->sc_rbavail = com_rbuf_size;
840 		com_iflush(sc);
841 		CLR(sc->sc_rx_flags, RX_ANY_BLOCK);
842 		com_hwiflow(sc);
843 
844 #ifdef COM_DEBUG
845 		if (com_debug)
846 			comstatus(sc, "comopen  ");
847 #endif
848 
849 		mutex_spin_exit(&sc->sc_lock);
850 	}
851 
852 	splx(s);
853 
854 	error = ttyopen(tp, COMDIALOUT(dev), ISSET(flag, O_NONBLOCK));
855 	if (error)
856 		goto bad;
857 
858 	error = (*tp->t_linesw->l_open)(dev, tp);
859 	if (error)
860 		goto bad;
861 
862 	return (0);
863 
864 bad:
865 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
866 		/*
867 		 * We failed to open the device, and nobody else had it opened.
868 		 * Clean up the state as appropriate.
869 		 */
870 		com_shutdown(sc);
871 	}
872 
873 	return (error);
874 }
875 
876 int
877 comclose(dev_t dev, int flag, int mode, struct lwp *l)
878 {
879 	struct com_softc *sc =
880 	    device_lookup_private(&com_cd, COMUNIT(dev));
881 	struct tty *tp = sc->sc_tty;
882 
883 	/* XXX This is for cons.c. */
884 	if (!ISSET(tp->t_state, TS_ISOPEN))
885 		return (0);
886 
887 	(*tp->t_linesw->l_close)(tp, flag);
888 	ttyclose(tp);
889 
890 	if (COM_ISALIVE(sc) == 0)
891 		return (0);
892 
893 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
894 		/*
895 		 * Although we got a last close, the device may still be in
896 		 * use; e.g. if this was the dialout node, and there are still
897 		 * processes waiting for carrier on the non-dialout node.
898 		 */
899 		com_shutdown(sc);
900 	}
901 
902 	return (0);
903 }
904 
905 int
906 comread(dev_t dev, struct uio *uio, int flag)
907 {
908 	struct com_softc *sc =
909 	    device_lookup_private(&com_cd, COMUNIT(dev));
910 	struct tty *tp = sc->sc_tty;
911 
912 	if (COM_ISALIVE(sc) == 0)
913 		return (EIO);
914 
915 	return ((*tp->t_linesw->l_read)(tp, uio, flag));
916 }
917 
918 int
919 comwrite(dev_t dev, struct uio *uio, int flag)
920 {
921 	struct com_softc *sc =
922 	    device_lookup_private(&com_cd, COMUNIT(dev));
923 	struct tty *tp = sc->sc_tty;
924 
925 	if (COM_ISALIVE(sc) == 0)
926 		return (EIO);
927 
928 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
929 }
930 
931 int
932 compoll(dev_t dev, int events, struct lwp *l)
933 {
934 	struct com_softc *sc =
935 	    device_lookup_private(&com_cd, COMUNIT(dev));
936 	struct tty *tp = sc->sc_tty;
937 
938 	if (COM_ISALIVE(sc) == 0)
939 		return (POLLHUP);
940 
941 	return ((*tp->t_linesw->l_poll)(tp, events, l));
942 }
943 
944 struct tty *
945 comtty(dev_t dev)
946 {
947 	struct com_softc *sc =
948 	    device_lookup_private(&com_cd, COMUNIT(dev));
949 	struct tty *tp = sc->sc_tty;
950 
951 	return (tp);
952 }
953 
954 int
955 comioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
956 {
957 	struct com_softc *sc;
958 	struct tty *tp;
959 	int error;
960 
961 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
962 	if (sc == NULL)
963 		return ENXIO;
964 	if (COM_ISALIVE(sc) == 0)
965 		return (EIO);
966 
967 	tp = sc->sc_tty;
968 
969 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
970 	if (error != EPASSTHROUGH)
971 		return (error);
972 
973 	error = ttioctl(tp, cmd, data, flag, l);
974 	if (error != EPASSTHROUGH)
975 		return (error);
976 
977 	error = 0;
978 	switch (cmd) {
979 	case TIOCSFLAGS:
980 		error = kauth_authorize_device_tty(l->l_cred,
981 		    KAUTH_DEVICE_TTY_PRIVSET, tp);
982 		break;
983 	default:
984 		/* nothing */
985 		break;
986 	}
987 	if (error) {
988 		return error;
989 	}
990 
991 	mutex_spin_enter(&sc->sc_lock);
992 
993 	switch (cmd) {
994 	case TIOCSBRK:
995 		com_break(sc, 1);
996 		break;
997 
998 	case TIOCCBRK:
999 		com_break(sc, 0);
1000 		break;
1001 
1002 	case TIOCSDTR:
1003 		com_modem(sc, 1);
1004 		break;
1005 
1006 	case TIOCCDTR:
1007 		com_modem(sc, 0);
1008 		break;
1009 
1010 	case TIOCGFLAGS:
1011 		*(int *)data = sc->sc_swflags;
1012 		break;
1013 
1014 	case TIOCSFLAGS:
1015 		sc->sc_swflags = *(int *)data;
1016 		break;
1017 
1018 	case TIOCMSET:
1019 	case TIOCMBIS:
1020 	case TIOCMBIC:
1021 		tiocm_to_com(sc, cmd, *(int *)data);
1022 		break;
1023 
1024 	case TIOCMGET:
1025 		*(int *)data = com_to_tiocm(sc);
1026 		break;
1027 
1028 	case PPS_IOC_CREATE:
1029 	case PPS_IOC_DESTROY:
1030 	case PPS_IOC_GETPARAMS:
1031 	case PPS_IOC_SETPARAMS:
1032 	case PPS_IOC_GETCAP:
1033 	case PPS_IOC_FETCH:
1034 #ifdef PPS_SYNC
1035 	case PPS_IOC_KCBIND:
1036 #endif
1037 		mutex_spin_enter(&timecounter_lock);
1038 		error = pps_ioctl(cmd, data, &sc->sc_pps_state);
1039 		mutex_spin_exit(&timecounter_lock);
1040 		break;
1041 
1042 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
1043 		mutex_spin_enter(&timecounter_lock);
1044 #ifndef PPS_TRAILING_EDGE
1045 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1046 		    &sc->sc_pps_state.ppsinfo.assert_timestamp);
1047 #else
1048 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1049 		    &sc->sc_pps_state.ppsinfo.clear_timestamp);
1050 #endif
1051 		mutex_spin_exit(&timecounter_lock);
1052 		break;
1053 
1054 	default:
1055 		error = EPASSTHROUGH;
1056 		break;
1057 	}
1058 
1059 	mutex_spin_exit(&sc->sc_lock);
1060 
1061 #ifdef COM_DEBUG
1062 	if (com_debug)
1063 		comstatus(sc, "comioctl ");
1064 #endif
1065 
1066 	return (error);
1067 }
1068 
1069 integrate void
1070 com_schedrx(struct com_softc *sc)
1071 {
1072 
1073 	sc->sc_rx_ready = 1;
1074 
1075 	/* Wake up the poller. */
1076 	softint_schedule(sc->sc_si);
1077 }
1078 
1079 void
1080 com_break(struct com_softc *sc, int onoff)
1081 {
1082 
1083 	if (onoff)
1084 		SET(sc->sc_lcr, LCR_SBREAK);
1085 	else
1086 		CLR(sc->sc_lcr, LCR_SBREAK);
1087 
1088 	if (!sc->sc_heldchange) {
1089 		if (sc->sc_tx_busy) {
1090 			sc->sc_heldtbc = sc->sc_tbc;
1091 			sc->sc_tbc = 0;
1092 			sc->sc_heldchange = 1;
1093 		} else
1094 			com_loadchannelregs(sc);
1095 	}
1096 }
1097 
1098 void
1099 com_modem(struct com_softc *sc, int onoff)
1100 {
1101 
1102 	if (sc->sc_mcr_dtr == 0)
1103 		return;
1104 
1105 	if (onoff)
1106 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1107 	else
1108 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1109 
1110 	if (!sc->sc_heldchange) {
1111 		if (sc->sc_tx_busy) {
1112 			sc->sc_heldtbc = sc->sc_tbc;
1113 			sc->sc_tbc = 0;
1114 			sc->sc_heldchange = 1;
1115 		} else
1116 			com_loadchannelregs(sc);
1117 	}
1118 }
1119 
1120 void
1121 tiocm_to_com(struct com_softc *sc, u_long how, int ttybits)
1122 {
1123 	u_char combits;
1124 
1125 	combits = 0;
1126 	if (ISSET(ttybits, TIOCM_DTR))
1127 		SET(combits, MCR_DTR);
1128 	if (ISSET(ttybits, TIOCM_RTS))
1129 		SET(combits, MCR_RTS);
1130 
1131 	switch (how) {
1132 	case TIOCMBIC:
1133 		CLR(sc->sc_mcr, combits);
1134 		break;
1135 
1136 	case TIOCMBIS:
1137 		SET(sc->sc_mcr, combits);
1138 		break;
1139 
1140 	case TIOCMSET:
1141 		CLR(sc->sc_mcr, MCR_DTR | MCR_RTS);
1142 		SET(sc->sc_mcr, combits);
1143 		break;
1144 	}
1145 
1146 	if (!sc->sc_heldchange) {
1147 		if (sc->sc_tx_busy) {
1148 			sc->sc_heldtbc = sc->sc_tbc;
1149 			sc->sc_tbc = 0;
1150 			sc->sc_heldchange = 1;
1151 		} else
1152 			com_loadchannelregs(sc);
1153 	}
1154 }
1155 
1156 int
1157 com_to_tiocm(struct com_softc *sc)
1158 {
1159 	u_char combits;
1160 	int ttybits = 0;
1161 
1162 	combits = sc->sc_mcr;
1163 	if (ISSET(combits, MCR_DTR))
1164 		SET(ttybits, TIOCM_DTR);
1165 	if (ISSET(combits, MCR_RTS))
1166 		SET(ttybits, TIOCM_RTS);
1167 
1168 	combits = sc->sc_msr;
1169 	if (ISSET(combits, MSR_DCD))
1170 		SET(ttybits, TIOCM_CD);
1171 	if (ISSET(combits, MSR_CTS))
1172 		SET(ttybits, TIOCM_CTS);
1173 	if (ISSET(combits, MSR_DSR))
1174 		SET(ttybits, TIOCM_DSR);
1175 	if (ISSET(combits, MSR_RI | MSR_TERI))
1176 		SET(ttybits, TIOCM_RI);
1177 
1178 	if (ISSET(sc->sc_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS | IER_EMSC))
1179 		SET(ttybits, TIOCM_LE);
1180 
1181 	return (ttybits);
1182 }
1183 
1184 static u_char
1185 cflag2lcr(tcflag_t cflag)
1186 {
1187 	u_char lcr = 0;
1188 
1189 	switch (ISSET(cflag, CSIZE)) {
1190 	case CS5:
1191 		SET(lcr, LCR_5BITS);
1192 		break;
1193 	case CS6:
1194 		SET(lcr, LCR_6BITS);
1195 		break;
1196 	case CS7:
1197 		SET(lcr, LCR_7BITS);
1198 		break;
1199 	case CS8:
1200 		SET(lcr, LCR_8BITS);
1201 		break;
1202 	}
1203 	if (ISSET(cflag, PARENB)) {
1204 		SET(lcr, LCR_PENAB);
1205 		if (!ISSET(cflag, PARODD))
1206 			SET(lcr, LCR_PEVEN);
1207 	}
1208 	if (ISSET(cflag, CSTOPB))
1209 		SET(lcr, LCR_STOPB);
1210 
1211 	return (lcr);
1212 }
1213 
1214 int
1215 comparam(struct tty *tp, struct termios *t)
1216 {
1217 	struct com_softc *sc =
1218 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1219 	int ospeed;
1220 	u_char lcr;
1221 
1222 	if (COM_ISALIVE(sc) == 0)
1223 		return (EIO);
1224 
1225 #ifdef COM_HAYESP
1226 	if (sc->sc_type == COM_TYPE_HAYESP) {
1227 		int prescaler, speed;
1228 
1229 		/*
1230 		 * Calculate UART clock prescaler.  It should be in
1231 		 * range of 0 .. 3.
1232 		 */
1233 		for (prescaler = 0, speed = t->c_ospeed; prescaler < 4;
1234 		    prescaler++, speed /= 2)
1235 			if ((ospeed = comspeed(speed, sc->sc_frequency,
1236 					       sc->sc_type)) > 0)
1237 				break;
1238 
1239 		if (prescaler == 4)
1240 			return (EINVAL);
1241 		sc->sc_prescaler = prescaler;
1242 	} else
1243 #endif
1244 	ospeed = comspeed(t->c_ospeed, sc->sc_frequency, sc->sc_type);
1245 
1246 	/* Check requested parameters. */
1247 	if (ospeed < 0)
1248 		return (EINVAL);
1249 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
1250 		return (EINVAL);
1251 
1252 	/*
1253 	 * For the console, always force CLOCAL and !HUPCL, so that the port
1254 	 * is always active.
1255 	 */
1256 	if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
1257 	    ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
1258 		SET(t->c_cflag, CLOCAL);
1259 		CLR(t->c_cflag, HUPCL);
1260 	}
1261 
1262 	/*
1263 	 * If there were no changes, don't do anything.  This avoids dropping
1264 	 * input and improves performance when all we did was frob things like
1265 	 * VMIN and VTIME.
1266 	 */
1267 	if (tp->t_ospeed == t->c_ospeed &&
1268 	    tp->t_cflag == t->c_cflag)
1269 		return (0);
1270 
1271 	lcr = ISSET(sc->sc_lcr, LCR_SBREAK) | cflag2lcr(t->c_cflag);
1272 
1273 	mutex_spin_enter(&sc->sc_lock);
1274 
1275 	sc->sc_lcr = lcr;
1276 
1277 	/*
1278 	 * If we're not in a mode that assumes a connection is present, then
1279 	 * ignore carrier changes.
1280 	 */
1281 	if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
1282 		sc->sc_msr_dcd = 0;
1283 	else
1284 		sc->sc_msr_dcd = MSR_DCD;
1285 	/*
1286 	 * Set the flow control pins depending on the current flow control
1287 	 * mode.
1288 	 */
1289 	if (ISSET(t->c_cflag, CRTSCTS)) {
1290 		sc->sc_mcr_dtr = MCR_DTR;
1291 		sc->sc_mcr_rts = MCR_RTS;
1292 		sc->sc_msr_cts = MSR_CTS;
1293 		sc->sc_efr = EFR_AUTORTS | EFR_AUTOCTS;
1294 	} else if (ISSET(t->c_cflag, MDMBUF)) {
1295 		/*
1296 		 * For DTR/DCD flow control, make sure we don't toggle DTR for
1297 		 * carrier detection.
1298 		 */
1299 		sc->sc_mcr_dtr = 0;
1300 		sc->sc_mcr_rts = MCR_DTR;
1301 		sc->sc_msr_cts = MSR_DCD;
1302 		sc->sc_efr = 0;
1303 	} else {
1304 		/*
1305 		 * If no flow control, then always set RTS.  This will make
1306 		 * the other side happy if it mistakenly thinks we're doing
1307 		 * RTS/CTS flow control.
1308 		 */
1309 		sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
1310 		sc->sc_mcr_rts = 0;
1311 		sc->sc_msr_cts = 0;
1312 		sc->sc_efr = 0;
1313 		if (ISSET(sc->sc_mcr, MCR_DTR))
1314 			SET(sc->sc_mcr, MCR_RTS);
1315 		else
1316 			CLR(sc->sc_mcr, MCR_RTS);
1317 	}
1318 	sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;
1319 
1320 #if 0
1321 	if (ospeed == 0)
1322 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1323 	else
1324 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1325 #endif
1326 
1327 	sc->sc_dlbl = ospeed;
1328 	sc->sc_dlbh = ospeed >> 8;
1329 
1330 	/*
1331 	 * Set the FIFO threshold based on the receive speed.
1332 	 *
1333 	 *  * If it's a low speed, it's probably a mouse or some other
1334 	 *    interactive device, so set the threshold low.
1335 	 *  * If it's a high speed, trim the trigger level down to prevent
1336 	 *    overflows.
1337 	 *  * Otherwise set it a bit higher.
1338 	 */
1339 	if (sc->sc_type == COM_TYPE_HAYESP)
1340 		sc->sc_fifo = FIFO_DMA_MODE | FIFO_ENABLE | FIFO_TRIGGER_8;
1341 	else if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
1342 		if (t->c_ospeed <= 1200)
1343 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
1344 		else if (t->c_ospeed <= 38400)
1345 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_8;
1346 		else
1347 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_4;
1348 	} else
1349 		sc->sc_fifo = 0;
1350 
1351 	/* And copy to tty. */
1352 	tp->t_ispeed = t->c_ospeed;
1353 	tp->t_ospeed = t->c_ospeed;
1354 	tp->t_cflag = t->c_cflag;
1355 
1356 	if (!sc->sc_heldchange) {
1357 		if (sc->sc_tx_busy) {
1358 			sc->sc_heldtbc = sc->sc_tbc;
1359 			sc->sc_tbc = 0;
1360 			sc->sc_heldchange = 1;
1361 		} else
1362 			com_loadchannelregs(sc);
1363 	}
1364 
1365 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1366 		/* Disable the high water mark. */
1367 		sc->sc_r_hiwat = 0;
1368 		sc->sc_r_lowat = 0;
1369 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1370 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1371 			com_schedrx(sc);
1372 		}
1373 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
1374 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
1375 			com_hwiflow(sc);
1376 		}
1377 	} else {
1378 		sc->sc_r_hiwat = com_rbuf_hiwat;
1379 		sc->sc_r_lowat = com_rbuf_lowat;
1380 	}
1381 
1382 	mutex_spin_exit(&sc->sc_lock);
1383 
1384 	/*
1385 	 * Update the tty layer's idea of the carrier bit, in case we changed
1386 	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
1387 	 * explicit request.
1388 	 */
1389 	(void) (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, MSR_DCD));
1390 
1391 #ifdef COM_DEBUG
1392 	if (com_debug)
1393 		comstatus(sc, "comparam ");
1394 #endif
1395 
1396 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1397 		if (sc->sc_tx_stopped) {
1398 			sc->sc_tx_stopped = 0;
1399 			comstart(tp);
1400 		}
1401 	}
1402 
1403 	return (0);
1404 }
1405 
1406 void
1407 com_iflush(struct com_softc *sc)
1408 {
1409 	struct com_regs	*regsp = &sc->sc_regs;
1410 #ifdef DIAGNOSTIC
1411 	int reg;
1412 #endif
1413 	int timo;
1414 
1415 #ifdef DIAGNOSTIC
1416 	reg = 0xffff;
1417 #endif
1418 	timo = 50000;
1419 	/* flush any pending I/O */
1420 	while (ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)
1421 	    && --timo)
1422 #ifdef DIAGNOSTIC
1423 		reg =
1424 #else
1425 		    (void)
1426 #endif
1427 		    CSR_READ_1(regsp, COM_REG_RXDATA);
1428 #ifdef DIAGNOSTIC
1429 	if (!timo)
1430 		aprint_error_dev(sc->sc_dev, "com_iflush timeout %02x\n", reg);
1431 #endif
1432 }
1433 
1434 void
1435 com_loadchannelregs(struct com_softc *sc)
1436 {
1437 	struct com_regs *regsp = &sc->sc_regs;
1438 
1439 	/* XXXXX necessary? */
1440 	com_iflush(sc);
1441 
1442 	if (sc->sc_type == COM_TYPE_PXA2x0)
1443 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
1444 	else
1445 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
1446 
1447 	if (ISSET(sc->sc_hwflags, COM_HW_FLOW)) {
1448 		if (sc->sc_type != COM_TYPE_AU1x00) {	/* no EFR on alchemy */
1449 			CSR_WRITE_1(regsp, COM_REG_EFR, sc->sc_efr);
1450 			CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
1451 		}
1452 	}
1453 	if (sc->sc_type == COM_TYPE_AU1x00) {
1454 		/* alchemy has single separate 16-bit clock divisor register */
1455 		CSR_WRITE_2(regsp, COM_REG_DLBL, sc->sc_dlbl +
1456 		    (sc->sc_dlbh << 8));
1457 	} else {
1458 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
1459 		CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
1460 		CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
1461 	}
1462 	CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
1463 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active = sc->sc_mcr);
1464 	CSR_WRITE_1(regsp, COM_REG_FIFO, sc->sc_fifo);
1465 #ifdef COM_HAYESP
1466 	if (sc->sc_type == COM_TYPE_HAYESP) {
1467 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
1468 		    HAYESP_SETPRESCALER);
1469 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
1470 		    sc->sc_prescaler);
1471 	}
1472 #endif
1473 
1474 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1475 }
1476 
1477 int
1478 comhwiflow(struct tty *tp, int block)
1479 {
1480 	struct com_softc *sc =
1481 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1482 
1483 	if (COM_ISALIVE(sc) == 0)
1484 		return (0);
1485 
1486 	if (sc->sc_mcr_rts == 0)
1487 		return (0);
1488 
1489 	mutex_spin_enter(&sc->sc_lock);
1490 
1491 	if (block) {
1492 		if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1493 			SET(sc->sc_rx_flags, RX_TTY_BLOCKED);
1494 			com_hwiflow(sc);
1495 		}
1496 	} else {
1497 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1498 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1499 			com_schedrx(sc);
1500 		}
1501 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1502 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED);
1503 			com_hwiflow(sc);
1504 		}
1505 	}
1506 
1507 	mutex_spin_exit(&sc->sc_lock);
1508 	return (1);
1509 }
1510 
1511 /*
1512  * (un)block input via hw flowcontrol
1513  */
1514 void
1515 com_hwiflow(struct com_softc *sc)
1516 {
1517 	struct com_regs *regsp= &sc->sc_regs;
1518 
1519 	if (sc->sc_mcr_rts == 0)
1520 		return;
1521 
1522 	if (ISSET(sc->sc_rx_flags, RX_ANY_BLOCK)) {
1523 		CLR(sc->sc_mcr, sc->sc_mcr_rts);
1524 		CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
1525 	} else {
1526 		SET(sc->sc_mcr, sc->sc_mcr_rts);
1527 		SET(sc->sc_mcr_active, sc->sc_mcr_rts);
1528 	}
1529 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active);
1530 }
1531 
1532 
1533 void
1534 comstart(struct tty *tp)
1535 {
1536 	struct com_softc *sc =
1537 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1538 	struct com_regs *regsp = &sc->sc_regs;
1539 	int s;
1540 
1541 	if (COM_ISALIVE(sc) == 0)
1542 		return;
1543 
1544 	s = spltty();
1545 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
1546 		goto out;
1547 	if (sc->sc_tx_stopped)
1548 		goto out;
1549 	if (!ttypull(tp))
1550 		goto out;
1551 
1552 	/* Grab the first contiguous region of buffer space. */
1553 	{
1554 		u_char *tba;
1555 		int tbc;
1556 
1557 		tba = tp->t_outq.c_cf;
1558 		tbc = ndqb(&tp->t_outq, 0);
1559 
1560 		mutex_spin_enter(&sc->sc_lock);
1561 
1562 		sc->sc_tba = tba;
1563 		sc->sc_tbc = tbc;
1564 	}
1565 
1566 	SET(tp->t_state, TS_BUSY);
1567 	sc->sc_tx_busy = 1;
1568 
1569 	/* Enable transmit completion interrupts if necessary. */
1570 	if (!ISSET(sc->sc_ier, IER_ETXRDY)) {
1571 		SET(sc->sc_ier, IER_ETXRDY);
1572 		CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1573 	}
1574 
1575 	/* Output the first chunk of the contiguous buffer. */
1576 	if (!ISSET(sc->sc_hwflags, COM_HW_NO_TXPRELOAD)) {
1577 		u_int n;
1578 
1579 		n = sc->sc_tbc;
1580 		if (n > sc->sc_fifolen)
1581 			n = sc->sc_fifolen;
1582 		CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
1583 		sc->sc_tbc -= n;
1584 		sc->sc_tba += n;
1585 	}
1586 
1587 	mutex_spin_exit(&sc->sc_lock);
1588 out:
1589 	splx(s);
1590 	return;
1591 }
1592 
1593 /*
1594  * Stop output on a line.
1595  */
1596 void
1597 comstop(struct tty *tp, int flag)
1598 {
1599 	struct com_softc *sc =
1600 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1601 
1602 	mutex_spin_enter(&sc->sc_lock);
1603 	if (ISSET(tp->t_state, TS_BUSY)) {
1604 		/* Stop transmitting at the next chunk. */
1605 		sc->sc_tbc = 0;
1606 		sc->sc_heldtbc = 0;
1607 		if (!ISSET(tp->t_state, TS_TTSTOP))
1608 			SET(tp->t_state, TS_FLUSH);
1609 	}
1610 	mutex_spin_exit(&sc->sc_lock);
1611 }
1612 
1613 void
1614 comdiag(void *arg)
1615 {
1616 	struct com_softc *sc = arg;
1617 	int overflows, floods;
1618 
1619 	mutex_spin_enter(&sc->sc_lock);
1620 	overflows = sc->sc_overflows;
1621 	sc->sc_overflows = 0;
1622 	floods = sc->sc_floods;
1623 	sc->sc_floods = 0;
1624 	sc->sc_errors = 0;
1625 	mutex_spin_exit(&sc->sc_lock);
1626 
1627 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
1628 	    device_xname(sc->sc_dev),
1629 	    overflows, overflows == 1 ? "" : "s",
1630 	    floods, floods == 1 ? "" : "s");
1631 }
1632 
1633 integrate void
1634 com_rxsoft(struct com_softc *sc, struct tty *tp)
1635 {
1636 	int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
1637 	u_char *get, *end;
1638 	u_int cc, scc;
1639 	u_char lsr;
1640 	int code;
1641 
1642 	end = sc->sc_ebuf;
1643 	get = sc->sc_rbget;
1644 	scc = cc = com_rbuf_size - sc->sc_rbavail;
1645 
1646 	if (cc == com_rbuf_size) {
1647 		sc->sc_floods++;
1648 		if (sc->sc_errors++ == 0)
1649 			callout_reset(&sc->sc_diag_callout, 60 * hz,
1650 			    comdiag, sc);
1651 	}
1652 
1653 	/* If not yet open, drop the entire buffer content here */
1654 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
1655 		get += cc << 1;
1656 		if (get >= end)
1657 			get -= com_rbuf_size << 1;
1658 		cc = 0;
1659 	}
1660 	while (cc) {
1661 		code = get[0];
1662 		lsr = get[1];
1663 		if (ISSET(lsr, LSR_OE | LSR_BI | LSR_FE | LSR_PE)) {
1664 			if (ISSET(lsr, LSR_OE)) {
1665 				sc->sc_overflows++;
1666 				if (sc->sc_errors++ == 0)
1667 					callout_reset(&sc->sc_diag_callout,
1668 					    60 * hz, comdiag, sc);
1669 			}
1670 			if (ISSET(lsr, LSR_BI | LSR_FE))
1671 				SET(code, TTY_FE);
1672 			if (ISSET(lsr, LSR_PE))
1673 				SET(code, TTY_PE);
1674 		}
1675 		if ((*rint)(code, tp) == -1) {
1676 			/*
1677 			 * The line discipline's buffer is out of space.
1678 			 */
1679 			if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1680 				/*
1681 				 * We're either not using flow control, or the
1682 				 * line discipline didn't tell us to block for
1683 				 * some reason.  Either way, we have no way to
1684 				 * know when there's more space available, so
1685 				 * just drop the rest of the data.
1686 				 */
1687 				get += cc << 1;
1688 				if (get >= end)
1689 					get -= com_rbuf_size << 1;
1690 				cc = 0;
1691 			} else {
1692 				/*
1693 				 * Don't schedule any more receive processing
1694 				 * until the line discipline tells us there's
1695 				 * space available (through comhwiflow()).
1696 				 * Leave the rest of the data in the input
1697 				 * buffer.
1698 				 */
1699 				SET(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1700 			}
1701 			break;
1702 		}
1703 		get += 2;
1704 		if (get >= end)
1705 			get = sc->sc_rbuf;
1706 		cc--;
1707 	}
1708 
1709 	if (cc != scc) {
1710 		sc->sc_rbget = get;
1711 		mutex_spin_enter(&sc->sc_lock);
1712 
1713 		cc = sc->sc_rbavail += scc - cc;
1714 		/* Buffers should be ok again, release possible block. */
1715 		if (cc >= sc->sc_r_lowat) {
1716 			if (ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
1717 				CLR(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
1718 				SET(sc->sc_ier, IER_ERXRDY);
1719 #ifdef COM_PXA2X0
1720 				if (sc->sc_type == COM_TYPE_PXA2x0)
1721 					SET(sc->sc_ier, IER_ERXTOUT);
1722 #endif
1723 				CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
1724 			}
1725 			if (ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED)) {
1726 				CLR(sc->sc_rx_flags, RX_IBUF_BLOCKED);
1727 				com_hwiflow(sc);
1728 			}
1729 		}
1730 		mutex_spin_exit(&sc->sc_lock);
1731 	}
1732 }
1733 
1734 integrate void
1735 com_txsoft(struct com_softc *sc, struct tty *tp)
1736 {
1737 
1738 	CLR(tp->t_state, TS_BUSY);
1739 	if (ISSET(tp->t_state, TS_FLUSH))
1740 		CLR(tp->t_state, TS_FLUSH);
1741 	else
1742 		ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
1743 	(*tp->t_linesw->l_start)(tp);
1744 }
1745 
1746 integrate void
1747 com_stsoft(struct com_softc *sc, struct tty *tp)
1748 {
1749 	u_char msr, delta;
1750 
1751 	mutex_spin_enter(&sc->sc_lock);
1752 	msr = sc->sc_msr;
1753 	delta = sc->sc_msr_delta;
1754 	sc->sc_msr_delta = 0;
1755 	mutex_spin_exit(&sc->sc_lock);
1756 
1757 	if (ISSET(delta, sc->sc_msr_dcd)) {
1758 		/*
1759 		 * Inform the tty layer that carrier detect changed.
1760 		 */
1761 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(msr, MSR_DCD));
1762 	}
1763 
1764 	if (ISSET(delta, sc->sc_msr_cts)) {
1765 		/* Block or unblock output according to flow control. */
1766 		if (ISSET(msr, sc->sc_msr_cts)) {
1767 			sc->sc_tx_stopped = 0;
1768 			(*tp->t_linesw->l_start)(tp);
1769 		} else {
1770 			sc->sc_tx_stopped = 1;
1771 		}
1772 	}
1773 
1774 #ifdef COM_DEBUG
1775 	if (com_debug)
1776 		comstatus(sc, "com_stsoft");
1777 #endif
1778 }
1779 
1780 void
1781 comsoft(void *arg)
1782 {
1783 	struct com_softc *sc = arg;
1784 	struct tty *tp;
1785 
1786 	if (COM_ISALIVE(sc) == 0)
1787 		return;
1788 
1789 	tp = sc->sc_tty;
1790 
1791 	if (sc->sc_rx_ready) {
1792 		sc->sc_rx_ready = 0;
1793 		com_rxsoft(sc, tp);
1794 	}
1795 
1796 	if (sc->sc_st_check) {
1797 		sc->sc_st_check = 0;
1798 		com_stsoft(sc, tp);
1799 	}
1800 
1801 	if (sc->sc_tx_done) {
1802 		sc->sc_tx_done = 0;
1803 		com_txsoft(sc, tp);
1804 	}
1805 }
1806 
1807 int
1808 comintr(void *arg)
1809 {
1810 	struct com_softc *sc = arg;
1811 	struct com_regs *regsp = &sc->sc_regs;
1812 
1813 	u_char *put, *end;
1814 	u_int cc;
1815 	u_char lsr, iir;
1816 
1817 	if (COM_ISALIVE(sc) == 0)
1818 		return (0);
1819 
1820 	mutex_spin_enter(&sc->sc_lock);
1821 	iir = CSR_READ_1(regsp, COM_REG_IIR);
1822 	if (ISSET(iir, IIR_NOPEND)) {
1823 		mutex_spin_exit(&sc->sc_lock);
1824 		return (0);
1825 	}
1826 
1827 	end = sc->sc_ebuf;
1828 	put = sc->sc_rbput;
1829 	cc = sc->sc_rbavail;
1830 
1831 again:	do {
1832 		u_char	msr, delta;
1833 
1834 		lsr = CSR_READ_1(regsp, COM_REG_LSR);
1835 		if (ISSET(lsr, LSR_BI)) {
1836 			int cn_trapped = 0;
1837 
1838 			cn_check_magic(sc->sc_tty->t_dev,
1839 				       CNC_BREAK, com_cnm_state);
1840 			if (cn_trapped)
1841 				continue;
1842 #if defined(KGDB) && !defined(DDB)
1843 			if (ISSET(sc->sc_hwflags, COM_HW_KGDB)) {
1844 				kgdb_connect(1);
1845 				continue;
1846 			}
1847 #endif
1848 		}
1849 
1850 		if (ISSET(lsr, LSR_RCV_MASK) &&
1851 		    !ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
1852 			while (cc > 0) {
1853 				int cn_trapped = 0;
1854 				put[0] = CSR_READ_1(regsp, COM_REG_RXDATA);
1855 				put[1] = lsr;
1856 				cn_check_magic(sc->sc_tty->t_dev,
1857 					       put[0], com_cnm_state);
1858 				if (cn_trapped)
1859 					goto next;
1860 				put += 2;
1861 				if (put >= end)
1862 					put = sc->sc_rbuf;
1863 				cc--;
1864 			next:
1865 				lsr = CSR_READ_1(regsp, COM_REG_LSR);
1866 				if (!ISSET(lsr, LSR_RCV_MASK))
1867 					break;
1868 			}
1869 
1870 			/*
1871 			 * Current string of incoming characters ended because
1872 			 * no more data was available or we ran out of space.
1873 			 * Schedule a receive event if any data was received.
1874 			 * If we're out of space, turn off receive interrupts.
1875 			 */
1876 			sc->sc_rbput = put;
1877 			sc->sc_rbavail = cc;
1878 			if (!ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED))
1879 				sc->sc_rx_ready = 1;
1880 
1881 			/*
1882 			 * See if we are in danger of overflowing a buffer. If
1883 			 * so, use hardware flow control to ease the pressure.
1884 			 */
1885 			if (!ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED) &&
1886 			    cc < sc->sc_r_hiwat) {
1887 				SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
1888 				com_hwiflow(sc);
1889 			}
1890 
1891 			/*
1892 			 * If we're out of space, disable receive interrupts
1893 			 * until the queue has drained a bit.
1894 			 */
1895 			if (!cc) {
1896 				SET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
1897 #ifdef COM_PXA2X0
1898 				if (sc->sc_type == COM_TYPE_PXA2x0)
1899 					CLR(sc->sc_ier, IER_ERXRDY|IER_ERXTOUT);
1900 				else
1901 #endif
1902 					CLR(sc->sc_ier, IER_ERXRDY);
1903 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1904 			}
1905 		} else {
1906 			if ((iir & (IIR_RXRDY|IIR_TXRDY)) == IIR_RXRDY) {
1907 				(void) CSR_READ_1(regsp, COM_REG_RXDATA);
1908 				continue;
1909 			}
1910 		}
1911 
1912 		msr = CSR_READ_1(regsp, COM_REG_MSR);
1913 		delta = msr ^ sc->sc_msr;
1914 		sc->sc_msr = msr;
1915 		if ((sc->sc_pps_state.ppsparam.mode & PPS_CAPTUREBOTH) &&
1916 		    (delta & MSR_DCD)) {
1917 			mutex_spin_enter(&timecounter_lock);
1918 			pps_capture(&sc->sc_pps_state);
1919 			pps_event(&sc->sc_pps_state,
1920 			    (msr & MSR_DCD) ?
1921 			    PPS_CAPTUREASSERT :
1922 			    PPS_CAPTURECLEAR);
1923 			mutex_spin_exit(&timecounter_lock);
1924 		}
1925 
1926 		/*
1927 		 * Process normal status changes
1928 		 */
1929 		if (ISSET(delta, sc->sc_msr_mask)) {
1930 			SET(sc->sc_msr_delta, delta);
1931 
1932 			/*
1933 			 * Stop output immediately if we lose the output
1934 			 * flow control signal or carrier detect.
1935 			 */
1936 			if (ISSET(~msr, sc->sc_msr_mask)) {
1937 				sc->sc_tbc = 0;
1938 				sc->sc_heldtbc = 0;
1939 #ifdef COM_DEBUG
1940 				if (com_debug)
1941 					comstatus(sc, "comintr  ");
1942 #endif
1943 			}
1944 
1945 			sc->sc_st_check = 1;
1946 		}
1947 	} while (!ISSET((iir =
1948 	    CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND) &&
1949 	    /*
1950 	     * Since some device (e.g., ST16C1550) doesn't clear IIR_TXRDY
1951 	     * by IIR read, so we can't do this way: `process all interrupts,
1952 	     * then do TX if possble'.
1953 	     */
1954 	    (iir & IIR_IMASK) != IIR_TXRDY);
1955 
1956 	/*
1957 	 * Read LSR again, since there may be an interrupt between
1958 	 * the last LSR read and IIR read above.
1959 	 */
1960 	lsr = CSR_READ_1(regsp, COM_REG_LSR);
1961 
1962 	/*
1963 	 * See if data can be transmitted as well.
1964 	 * Schedule tx done event if no data left
1965 	 * and tty was marked busy.
1966 	 */
1967 	if (ISSET(lsr, LSR_TXRDY)) {
1968 		/*
1969 		 * If we've delayed a parameter change, do it now, and restart
1970 		 * output.
1971 		 */
1972 		if (sc->sc_heldchange) {
1973 			com_loadchannelregs(sc);
1974 			sc->sc_heldchange = 0;
1975 			sc->sc_tbc = sc->sc_heldtbc;
1976 			sc->sc_heldtbc = 0;
1977 		}
1978 
1979 		/* Output the next chunk of the contiguous buffer, if any. */
1980 		if (sc->sc_tbc > 0) {
1981 			u_int n;
1982 
1983 			n = sc->sc_tbc;
1984 			if (n > sc->sc_fifolen)
1985 				n = sc->sc_fifolen;
1986 			CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
1987 			sc->sc_tbc -= n;
1988 			sc->sc_tba += n;
1989 		} else {
1990 			/* Disable transmit completion interrupts if necessary. */
1991 			if (ISSET(sc->sc_ier, IER_ETXRDY)) {
1992 				CLR(sc->sc_ier, IER_ETXRDY);
1993 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1994 			}
1995 			if (sc->sc_tx_busy) {
1996 				sc->sc_tx_busy = 0;
1997 				sc->sc_tx_done = 1;
1998 			}
1999 		}
2000 	}
2001 
2002 	if (!ISSET((iir = CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND))
2003 		goto again;
2004 
2005 	mutex_spin_exit(&sc->sc_lock);
2006 
2007 	/* Wake up the poller. */
2008 	softint_schedule(sc->sc_si);
2009 
2010 #if NRND > 0 && defined(RND_COM)
2011 	rnd_add_uint32(&sc->rnd_source, iir | lsr);
2012 #endif
2013 
2014 	return (1);
2015 }
2016 
2017 /*
2018  * The following functions are polled getc and putc routines, shared
2019  * by the console and kgdb glue.
2020  *
2021  * The read-ahead code is so that you can detect pending in-band
2022  * cn_magic in polled mode while doing output rather than having to
2023  * wait until the kernel decides it needs input.
2024  */
2025 
2026 #define MAX_READAHEAD	20
2027 static int com_readahead[MAX_READAHEAD];
2028 static int com_readaheadcount = 0;
2029 
2030 int
2031 com_common_getc(dev_t dev, struct com_regs *regsp)
2032 {
2033 	int s = splserial();
2034 	u_char stat, c;
2035 
2036 	/* got a character from reading things earlier */
2037 	if (com_readaheadcount > 0) {
2038 		int i;
2039 
2040 		c = com_readahead[0];
2041 		for (i = 1; i < com_readaheadcount; i++) {
2042 			com_readahead[i-1] = com_readahead[i];
2043 		}
2044 		com_readaheadcount--;
2045 		splx(s);
2046 		return (c);
2047 	}
2048 
2049 	/* block until a character becomes available */
2050 	while (!ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY))
2051 		;
2052 
2053 	c = CSR_READ_1(regsp, COM_REG_RXDATA);
2054 	stat = CSR_READ_1(regsp, COM_REG_IIR);
2055 	{
2056 		int cn_trapped = 0; /* unused */
2057 #ifdef DDB
2058 		extern int db_active;
2059 		if (!db_active)
2060 #endif
2061 			cn_check_magic(dev, c, com_cnm_state);
2062 	}
2063 	splx(s);
2064 	return (c);
2065 }
2066 
2067 void
2068 com_common_putc(dev_t dev, struct com_regs *regsp, int c)
2069 {
2070 	int s = splserial();
2071 	int cin, stat, timo;
2072 
2073 	if (com_readaheadcount < MAX_READAHEAD
2074 	     && ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
2075 		int cn_trapped = 0;
2076 		cin = CSR_READ_1(regsp, COM_REG_RXDATA);
2077 		stat = CSR_READ_1(regsp, COM_REG_IIR);
2078 		cn_check_magic(dev, cin, com_cnm_state);
2079 		com_readahead[com_readaheadcount++] = cin;
2080 	}
2081 
2082 	/* wait for any pending transmission to finish */
2083 	timo = 150000;
2084 	while (!ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_TXRDY) && --timo)
2085 		continue;
2086 
2087 	CSR_WRITE_1(regsp, COM_REG_TXDATA, c);
2088 	COM_BARRIER(regsp, BR | BW);
2089 
2090 	splx(s);
2091 }
2092 
2093 /*
2094  * Initialize UART for use as console or KGDB line.
2095  */
2096 int
2097 cominit(struct com_regs *regsp, int rate, int frequency, int type,
2098     tcflag_t cflag)
2099 {
2100 
2101 	if (bus_space_map(regsp->cr_iot, regsp->cr_iobase, regsp->cr_nports, 0,
2102 		&regsp->cr_ioh))
2103 		return (ENOMEM); /* ??? */
2104 
2105 	rate = comspeed(rate, frequency, type);
2106 	if (type != COM_TYPE_AU1x00) {
2107 		/* no EFR on alchemy */
2108 		CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
2109 		CSR_WRITE_1(regsp, COM_REG_EFR, 0);
2110 		CSR_WRITE_1(regsp, COM_REG_LCR, LCR_DLAB);
2111 		CSR_WRITE_1(regsp, COM_REG_DLBL, rate & 0xff);
2112 		CSR_WRITE_1(regsp, COM_REG_DLBH, rate >> 8);
2113 	} else {
2114 		CSR_WRITE_1(regsp, COM_REG_DLBL, rate);
2115 	}
2116 	CSR_WRITE_1(regsp, COM_REG_LCR, cflag2lcr(cflag));
2117 	CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2118 	CSR_WRITE_1(regsp, COM_REG_FIFO,
2119 	    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
2120 #ifdef COM_PXA2X0
2121 	if (type == COM_TYPE_PXA2x0)
2122 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
2123 	else
2124 #endif
2125 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
2126 
2127 	return (0);
2128 }
2129 
2130 /*
2131  * Following are all routines needed for COM to act as console
2132  */
2133 struct consdev comcons = {
2134 	NULL, NULL, comcngetc, comcnputc, comcnpollc, NULL, NULL, NULL,
2135 	NODEV, CN_NORMAL
2136 };
2137 
2138 
2139 int
2140 comcnattach1(struct com_regs *regsp, int rate, int frequency, int type,
2141     tcflag_t cflag)
2142 {
2143 	int res;
2144 
2145 	comconsregs = *regsp;
2146 
2147 	res = cominit(&comconsregs, rate, frequency, type, cflag);
2148 	if (res)
2149 		return (res);
2150 
2151 	cn_tab = &comcons;
2152 	cn_init_magic(&com_cnm_state);
2153 	cn_set_magic("\047\001"); /* default magic is BREAK */
2154 
2155 	comconsrate = rate;
2156 	comconscflag = cflag;
2157 
2158 	return (0);
2159 }
2160 
2161 int
2162 comcnattach(bus_space_tag_t iot, bus_addr_t iobase, int rate, int frequency,
2163     int type, tcflag_t cflag)
2164 {
2165 	struct com_regs	regs;
2166 
2167 	memset(&regs, 0, sizeof regs);
2168 	regs.cr_iot = iot;
2169 	regs.cr_iobase = iobase;
2170 	regs.cr_nports = COM_NPORTS;
2171 #ifdef	COM_REGMAP
2172 	memcpy(regs.cr_map, com_std_map, sizeof (regs.cr_map));
2173 #endif
2174 
2175 	return comcnattach1(&regs, rate, frequency, type, cflag);
2176 }
2177 
2178 int
2179 comcngetc(dev_t dev)
2180 {
2181 
2182 	return (com_common_getc(dev, &comconsregs));
2183 }
2184 
2185 /*
2186  * Console kernel output character routine.
2187  */
2188 void
2189 comcnputc(dev_t dev, int c)
2190 {
2191 
2192 	com_common_putc(dev, &comconsregs, c);
2193 }
2194 
2195 void
2196 comcnpollc(dev_t dev, int on)
2197 {
2198 
2199 }
2200 
2201 #ifdef KGDB
2202 int
2203 com_kgdb_attach1(struct com_regs *regsp, int rate, int frequency, int type,
2204     tcflag_t cflag)
2205 {
2206 	int res;
2207 
2208 	if (regsp->cr_iot == comconsregs.cr_iot &&
2209 	    regsp->cr_iobase == comconsregs.cr_iobase) {
2210 #if !defined(DDB)
2211 		return (EBUSY); /* cannot share with console */
2212 #else
2213 		comkgdbregs = *regsp;
2214 		comkgdbregs.cr_ioh = comconsregs.cr_ioh;
2215 #endif
2216 	} else {
2217 		comkgdbregs = *regsp;
2218 		res = cominit(&comkgdbregs, rate, frequency, type, cflag);
2219 		if (res)
2220 			return (res);
2221 
2222 		/*
2223 		 * XXXfvdl this shouldn't be needed, but the cn_magic goo
2224 		 * expects this to be initialized
2225 		 */
2226 		cn_init_magic(&com_cnm_state);
2227 		cn_set_magic("\047\001");
2228 	}
2229 
2230 	kgdb_attach(com_kgdb_getc, com_kgdb_putc, NULL);
2231 	kgdb_dev = 123; /* unneeded, only to satisfy some tests */
2232 
2233 	return (0);
2234 }
2235 
2236 int
2237 com_kgdb_attach(bus_space_tag_t iot, bus_addr_t iobase, int rate,
2238     int frequency, int type, tcflag_t cflag)
2239 {
2240 	struct com_regs regs;
2241 
2242 	regs.cr_iot = iot;
2243 	regs.cr_nports = COM_NPORTS;
2244 	regs.cr_iobase = iobase;
2245 #ifdef COM_REGMAP
2246 	memcpy(regs.cr_map, com_std_map, sizeof (regs.cr_map));
2247 #endif
2248 
2249 	return com_kgdb_attach1(&regs, rate, frequency, type, cflag);
2250 }
2251 
2252 /* ARGSUSED */
2253 int
2254 com_kgdb_getc(void *arg)
2255 {
2256 
2257 	return (com_common_getc(NODEV, &comkgdbregs));
2258 }
2259 
2260 /* ARGSUSED */
2261 void
2262 com_kgdb_putc(void *arg, int c)
2263 {
2264 
2265 	com_common_putc(NODEV, &comkgdbregs, c);
2266 }
2267 #endif /* KGDB */
2268 
2269 /* helper function to identify the com ports used by
2270  console or KGDB (and not yet autoconf attached) */
2271 int
2272 com_is_console(bus_space_tag_t iot, bus_addr_t iobase, bus_space_handle_t *ioh)
2273 {
2274 	bus_space_handle_t help;
2275 
2276 	if (!comconsattached &&
2277 	    iot == comconsregs.cr_iot && iobase == comconsregs.cr_iobase)
2278 		help = comconsregs.cr_ioh;
2279 #ifdef KGDB
2280 	else if (!com_kgdb_attached &&
2281 	    iot == comkgdbregs.cr_iot && iobase == comkgdbregs.cr_iobase)
2282 		help = comkgdbregs.cr_ioh;
2283 #endif
2284 	else
2285 		return (0);
2286 
2287 	if (ioh)
2288 		*ioh = help;
2289 	return (1);
2290 }
2291 
2292 /*
2293  * this routine exists to serve as a shutdown hook for systems that
2294  * have firmware which doesn't interact properly with a com device in
2295  * FIFO mode.
2296  */
2297 bool
2298 com_cleanup(device_t self, int how)
2299 {
2300 	struct com_softc *sc = device_private(self);
2301 
2302 	if (ISSET(sc->sc_hwflags, COM_HW_FIFO))
2303 		CSR_WRITE_1(&sc->sc_regs, COM_REG_FIFO, 0);
2304 
2305 	return true;
2306 }
2307 
2308 bool
2309 com_suspend(device_t self PMF_FN_ARGS)
2310 {
2311 	struct com_softc *sc = device_private(self);
2312 
2313 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, 0);
2314 	(void)CSR_READ_1(&sc->sc_regs, COM_REG_IIR);
2315 
2316 	return true;
2317 }
2318 
2319 bool
2320 com_resume(device_t self PMF_FN_ARGS)
2321 {
2322 	struct com_softc *sc = device_private(self);
2323 
2324 	mutex_spin_enter(&sc->sc_lock);
2325 	com_loadchannelregs(sc);
2326 	mutex_spin_exit(&sc->sc_lock);
2327 
2328 	return true;
2329 }
2330