xref: /netbsd-src/sys/dev/ic/com.c (revision cac8e449158efc7261bebc8657cbb0125a2cfdde)
1 /*	com.c,v 1.262.2.3 2008/01/09 01:52:50 matt 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  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*
33  * Copyright (c) 1991 The Regents of the University of California.
34  * All rights reserved.
35  *
36  * Redistribution and use in source and binary forms, with or without
37  * modification, are permitted provided that the following conditions
38  * are met:
39  * 1. Redistributions of source code must retain the above copyright
40  *    notice, this list of conditions and the following disclaimer.
41  * 2. Redistributions in binary form must reproduce the above copyright
42  *    notice, this list of conditions and the following disclaimer in the
43  *    documentation and/or other materials provided with the distribution.
44  * 3. Neither the name of the University nor the names of its contributors
45  *    may be used to endorse or promote products derived from this software
46  *    without specific prior written permission.
47  *
48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58  * SUCH DAMAGE.
59  *
60  *	@(#)com.c	7.5 (Berkeley) 5/16/91
61  */
62 
63 /*
64  * COM driver, uses National Semiconductor NS16450/NS16550AF UART
65  * Supports automatic hardware flow control on StarTech ST16C650A UART
66  */
67 
68 #include <sys/cdefs.h>
69 __KERNEL_RCSID(0, "com.c,v 1.262.2.3 2008/01/09 01:52:50 matt Exp");
70 
71 #include "opt_com.h"
72 #include "opt_ddb.h"
73 #include "opt_kgdb.h"
74 #include "opt_lockdebug.h"
75 #include "opt_multiprocessor.h"
76 #include "opt_ntp.h"
77 
78 #include "rnd.h"
79 #if NRND > 0 && defined(RND_COM)
80 #include <sys/rnd.h>
81 #endif
82 
83 /* The COM16650 option was renamed to COM_16650. */
84 #ifdef COM16650
85 #error Obsolete COM16650 option; use COM_16650 instead.
86 #endif
87 
88 /*
89  * Override cnmagic(9) macro before including <sys/systm.h>.
90  * We need to know if cn_check_magic triggered debugger, so set a flag.
91  * Callers of cn_check_magic must declare int cn_trapped = 0;
92  * XXX: this is *ugly*!
93  */
94 #define cn_trap()				\
95 	do {					\
96 		console_debugger();		\
97 		cn_trapped = 1;			\
98 	} while (/* CONSTCOND */ 0)
99 
100 #include <sys/param.h>
101 #include <sys/systm.h>
102 #include <sys/ioctl.h>
103 #include <sys/select.h>
104 #include <sys/poll.h>
105 #include <sys/tty.h>
106 #include <sys/proc.h>
107 #include <sys/user.h>
108 #include <sys/conf.h>
109 #include <sys/file.h>
110 #include <sys/uio.h>
111 #include <sys/kernel.h>
112 #include <sys/syslog.h>
113 #include <sys/device.h>
114 #include <sys/malloc.h>
115 #include <sys/timepps.h>
116 #include <sys/vnode.h>
117 #include <sys/kauth.h>
118 #include <sys/intr.h>
119 
120 #include <sys/bus.h>
121 
122 #include <dev/ic/comreg.h>
123 #include <dev/ic/comvar.h>
124 #include <dev/ic/ns16550reg.h>
125 #include <dev/ic/st16650reg.h>
126 #ifdef COM_HAYESP
127 #include <dev/ic/hayespreg.h>
128 #endif
129 #define	com_lcr	com_cfcr
130 #include <dev/cons.h>
131 
132 #ifdef	COM_REGMAP
133 #define	CSR_WRITE_1(r, o, v)	\
134 	bus_space_write_1((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o], v)
135 #define	CSR_READ_1(r, o)	\
136 	bus_space_read_1((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o])
137 #define	CSR_WRITE_2(r, o, v)	\
138 	bus_space_write_2((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o], v)
139 #define	CSR_READ_2(r, o)	\
140 	bus_space_read_2((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o])
141 #define	CSR_WRITE_MULTI(r, o, p, n)	\
142 	bus_space_write_multi_1((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o], p, n)
143 #else
144 #define	CSR_WRITE_1(r, o, v)	\
145 	bus_space_write_1((r)->cr_iot, (r)->cr_ioh, o, v)
146 #define	CSR_READ_1(r, o)	\
147 	bus_space_read_1((r)->cr_iot, (r)->cr_ioh, o)
148 #define	CSR_WRITE_2(r, o, v)	\
149 	bus_space_write_2((r)->cr_iot, (r)->cr_ioh, o, v)
150 #define	CSR_READ_2(r, o)	\
151 	bus_space_read_2((r)->cr_iot, (r)->cr_ioh, o)
152 #define	CSR_WRITE_MULTI(r, o, p, n)	\
153 	bus_space_write_multi_1((r)->cr_iot, (r)->cr_ioh, o, p, n)
154 #endif
155 
156 
157 static void com_enable_debugport(struct com_softc *);
158 
159 void	com_config(struct com_softc *);
160 void	com_shutdown(struct com_softc *);
161 int	comspeed(long, long, int);
162 static	u_char	cflag2lcr(tcflag_t);
163 int	comparam(struct tty *, struct termios *);
164 void	comstart(struct tty *);
165 int	comhwiflow(struct tty *, int);
166 
167 void	com_loadchannelregs(struct com_softc *);
168 void	com_hwiflow(struct com_softc *);
169 void	com_break(struct com_softc *, int);
170 void	com_modem(struct com_softc *, int);
171 void	tiocm_to_com(struct com_softc *, u_long, int);
172 int	com_to_tiocm(struct com_softc *);
173 void	com_iflush(struct com_softc *);
174 
175 int	com_common_getc(dev_t, struct com_regs *);
176 void	com_common_putc(dev_t, struct com_regs *, int);
177 
178 int	cominit(struct com_regs *, int, int, int, tcflag_t);
179 
180 int	comcngetc(dev_t);
181 void	comcnputc(dev_t, int);
182 void	comcnpollc(dev_t, int);
183 
184 #define	integrate	static inline
185 void 	comsoft(void *);
186 integrate void com_rxsoft(struct com_softc *, struct tty *);
187 integrate void com_txsoft(struct com_softc *, struct tty *);
188 integrate void com_stsoft(struct com_softc *, struct tty *);
189 integrate void com_schedrx(struct com_softc *);
190 void	comdiag(void *);
191 
192 extern struct cfdriver com_cd;
193 
194 dev_type_open(comopen);
195 dev_type_close(comclose);
196 dev_type_read(comread);
197 dev_type_write(comwrite);
198 dev_type_ioctl(comioctl);
199 dev_type_stop(comstop);
200 dev_type_tty(comtty);
201 dev_type_poll(compoll);
202 
203 const struct cdevsw com_cdevsw = {
204 	comopen, comclose, comread, comwrite, comioctl,
205 	comstop, comtty, compoll, nommap, ttykqfilter, D_TTY
206 };
207 
208 /*
209  * Make this an option variable one can patch.
210  * But be warned:  this must be a power of 2!
211  */
212 u_int com_rbuf_size = COM_RING_SIZE;
213 
214 /* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
215 u_int com_rbuf_hiwat = (COM_RING_SIZE * 1) / 4;
216 u_int com_rbuf_lowat = (COM_RING_SIZE * 3) / 4;
217 
218 static struct com_regs comconsregs;
219 static int comconsattached;
220 static int comconsrate;
221 static tcflag_t comconscflag;
222 static struct cnm_state com_cnm_state;
223 
224 #ifdef KGDB
225 #include <sys/kgdb.h>
226 
227 static struct com_regs comkgdbregs;
228 static int com_kgdb_attached;
229 
230 int	com_kgdb_getc(void *);
231 void	com_kgdb_putc(void *, int);
232 #endif /* KGDB */
233 
234 #ifdef COM_REGMAP
235 /* initializer for typical 16550-ish hardware */
236 #define	COM_REG_16550	{ \
237 	com_data, com_data, com_dlbl, com_dlbh, com_ier, com_iir, com_fifo, \
238 	com_efr, com_lcr, com_mcr, com_lsr, com_msr }
239 
240 const bus_size_t com_std_map[16] = COM_REG_16550;
241 #endif /* COM_REGMAP */
242 
243 #define	COMUNIT_MASK	0x7ffff
244 #define	COMDIALOUT_MASK	0x80000
245 
246 #define	COMUNIT(x)	(minor(x) & COMUNIT_MASK)
247 #define	COMDIALOUT(x)	(minor(x) & COMDIALOUT_MASK)
248 
249 #define	COM_ISALIVE(sc)	((sc)->enabled != 0 && \
250 			 device_is_active((sc)->sc_dev))
251 
252 #define	BR	BUS_SPACE_BARRIER_READ
253 #define	BW	BUS_SPACE_BARRIER_WRITE
254 #define COM_BARRIER(r, f) \
255 	bus_space_barrier((r)->cr_iot, (r)->cr_ioh, 0, (r)->cr_nports, (f))
256 
257 /*ARGSUSED*/
258 int
259 comspeed(long speed, long frequency, int type)
260 {
261 #define	divrnd(n, q)	(((n)*2/(q)+1)/2)	/* divide and round off */
262 
263 	int x, err;
264 	int divisor = 16;
265 
266 	if ((type == COM_TYPE_OMAP) && (speed > 230400)) {
267 	    divisor = 13;
268 	}
269 
270 #if 0
271 	if (speed == 0)
272 		return (0);
273 #endif
274 	if (speed <= 0)
275 		return (-1);
276 	x = divrnd(frequency / divisor, speed);
277 	if (x <= 0)
278 		return (-1);
279 	err = divrnd(((quad_t)frequency) * 1000 / divisor, speed * x) - 1000;
280 	if (err < 0)
281 		err = -err;
282 	if (err > COM_TOLERANCE)
283 		return (-1);
284 	return (x);
285 
286 #undef	divrnd
287 }
288 
289 #ifdef COM_DEBUG
290 int	com_debug = 0;
291 
292 void comstatus(struct com_softc *, const char *);
293 void
294 comstatus(struct com_softc *sc, const char *str)
295 {
296 	struct tty *tp = sc->sc_tty;
297 
298 	aprint_normal_dev(sc->sc_dev,
299 	    "%s %cclocal  %cdcd %cts_carr_on %cdtr %ctx_stopped\n",
300 	    str,
301 	    ISSET(tp->t_cflag, CLOCAL) ? '+' : '-',
302 	    ISSET(sc->sc_msr, MSR_DCD) ? '+' : '-',
303 	    ISSET(tp->t_state, TS_CARR_ON) ? '+' : '-',
304 	    ISSET(sc->sc_mcr, MCR_DTR) ? '+' : '-',
305 	    sc->sc_tx_stopped ? '+' : '-');
306 
307 	aprint_normal_dev(sc->sc_dev,
308 	    "%s %ccrtscts %ccts %cts_ttstop  %crts rx_flags=0x%x\n",
309 	    str,
310 	    ISSET(tp->t_cflag, CRTSCTS) ? '+' : '-',
311 	    ISSET(sc->sc_msr, MSR_CTS) ? '+' : '-',
312 	    ISSET(tp->t_state, TS_TTSTOP) ? '+' : '-',
313 	    ISSET(sc->sc_mcr, MCR_RTS) ? '+' : '-',
314 	    sc->sc_rx_flags);
315 }
316 #endif
317 
318 int
319 com_probe_subr(struct com_regs *regs)
320 {
321 
322 	/* force access to id reg */
323 	CSR_WRITE_1(regs, COM_REG_LCR, LCR_8BITS);
324 	CSR_WRITE_1(regs, COM_REG_IIR, 0);
325 	if ((CSR_READ_1(regs, COM_REG_LCR) != LCR_8BITS) ||
326 	    (CSR_READ_1(regs, COM_REG_IIR) & 0x38))
327 		return (0);
328 
329 	return (1);
330 }
331 
332 int
333 comprobe1(bus_space_tag_t iot, bus_space_handle_t ioh)
334 {
335 	struct com_regs	regs;
336 
337 	regs.cr_iot = iot;
338 	regs.cr_ioh = ioh;
339 #ifdef	COM_REGMAP
340 	memcpy(regs.cr_map, com_std_map, sizeof (regs.cr_map));;
341 #endif
342 
343 	return com_probe_subr(&regs);
344 }
345 
346 /*
347  * No locking in this routine; it is only called during attach,
348  * or with the port already locked.
349  */
350 static void
351 com_enable_debugport(struct com_softc *sc)
352 {
353 
354 	/* Turn on line break interrupt, set carrier. */
355 	sc->sc_ier = IER_ERXRDY;
356 	if (sc->sc_type == COM_TYPE_PXA2x0)
357 		sc->sc_ier |= IER_EUART | IER_ERXTOUT;
358 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
359 	SET(sc->sc_mcr, MCR_DTR | MCR_RTS);
360 	CSR_WRITE_1(&sc->sc_regs, COM_REG_MCR, sc->sc_mcr);
361 }
362 
363 void
364 com_attach_subr(struct com_softc *sc)
365 {
366 	struct com_regs *regsp = &sc->sc_regs;
367 	struct tty *tp;
368 #ifdef COM_16650
369 	u_int8_t lcr;
370 #endif
371 	const char *fifo_msg = NULL;
372 
373 	aprint_naive("\n");
374 
375 	callout_init(&sc->sc_diag_callout, 0);
376 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_HIGH);
377 
378 	/* Disable interrupts before configuring the device. */
379 	if (sc->sc_type == COM_TYPE_PXA2x0)
380 		sc->sc_ier = IER_EUART;
381 	else
382 		sc->sc_ier = 0;
383 
384 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
385 
386 	if (regsp->cr_iot == comconsregs.cr_iot &&
387 	    regsp->cr_iobase == comconsregs.cr_iobase) {
388 		comconsattached = 1;
389 
390 		/* Make sure the console is always "hardwired". */
391 		delay(10000);			/* wait for output to finish */
392 		SET(sc->sc_hwflags, COM_HW_CONSOLE);
393 		SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
394 	}
395 
396 	/* Probe for FIFO */
397 	switch (sc->sc_type) {
398 	case COM_TYPE_HAYESP:
399 		goto fifodone;
400 
401 	case COM_TYPE_AU1x00:
402 		sc->sc_fifolen = 16;
403 		fifo_msg = "Au1X00 UART, working fifo";
404 		SET(sc->sc_hwflags, COM_HW_FIFO);
405 		goto fifodelay;
406 
407  	case COM_TYPE_OMAP:
408  		sc->sc_fifolen = 64;
409  		fifo_msg = "OMAP UART, working fifo";
410  		SET(sc->sc_hwflags, COM_HW_FIFO);
411  		goto fifodelay;
412   	}
413 
414 	sc->sc_fifolen = 1;
415 	/* look for a NS 16550AF UART with FIFOs */
416 	CSR_WRITE_1(regsp, COM_REG_FIFO,
417 	    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_14);
418 	delay(100);
419 	if (ISSET(CSR_READ_1(regsp, COM_REG_IIR), IIR_FIFO_MASK)
420 	    == IIR_FIFO_MASK)
421 		if (ISSET(CSR_READ_1(regsp, COM_REG_FIFO), FIFO_TRIGGER_14)
422 		    == FIFO_TRIGGER_14) {
423 			SET(sc->sc_hwflags, COM_HW_FIFO);
424 
425 #ifdef COM_16650
426 			/*
427 			 * IIR changes into the EFR if LCR is set to LCR_EERS
428 			 * on 16650s. We also know IIR != 0 at this point.
429 			 * Write 0 into the EFR, and read it. If the result
430 			 * is 0, we have a 16650.
431 			 *
432 			 * Older 16650s were broken; the test to detect them
433 			 * is taken from the Linux driver. Apparently
434 			 * setting DLAB enable gives access to the EFR on
435 			 * these chips.
436 			 */
437 			lcr = CSR_READ_1(regsp, COM_REG_LCR);
438 			CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
439 			CSR_WRITE_1(regsp, COM_REG_EFR, 0);
440 			if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
441 				CSR_WRITE_1(regsp, COM_REG_LCR,
442 				    lcr | LCR_DLAB);
443 				if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
444 					CLR(sc->sc_hwflags, COM_HW_FIFO);
445 					sc->sc_fifolen = 0;
446 				} else {
447 					SET(sc->sc_hwflags, COM_HW_FLOW);
448 					sc->sc_fifolen = 32;
449 				}
450 			} else
451 #endif
452 				sc->sc_fifolen = 16;
453 
454 #ifdef COM_16650
455 			CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
456 			if (sc->sc_fifolen == 0)
457 				fifo_msg = "st16650, broken fifo";
458 			else if (sc->sc_fifolen == 32)
459 				fifo_msg = "st16650a, working fifo";
460 			else
461 #endif
462 				fifo_msg = "ns16550a, working fifo";
463 		} else
464 			fifo_msg = "ns16550, broken fifo";
465 	else
466 		fifo_msg = "ns8250 or ns16450, no fifo";
467 	CSR_WRITE_1(regsp, COM_REG_FIFO, 0);
468 fifodelay:
469 	/*
470 	 * Some chips will clear down both Tx and Rx FIFOs when zero is
471 	 * written to com_fifo. If this chip is the console, writing zero
472 	 * results in some of the chip/FIFO description being lost, so delay
473 	 * printing it until now.
474 	 */
475 	delay(10);
476 	aprint_normal(": %s\n", fifo_msg);
477 	if (ISSET(sc->sc_hwflags, COM_HW_TXFIFO_DISABLE)) {
478 		sc->sc_fifolen = 1;
479 		aprint_normal_dev(sc->sc_dev, "txfifo disabled\n");
480 	}
481 
482 fifodone:
483 
484 	tp = ttymalloc();
485 	tp->t_oproc = comstart;
486 	tp->t_param = comparam;
487 	tp->t_hwiflow = comhwiflow;
488 
489 	sc->sc_tty = tp;
490 	sc->sc_rbuf = malloc(com_rbuf_size << 1, M_DEVBUF, M_NOWAIT);
491 	sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
492 	sc->sc_rbavail = com_rbuf_size;
493 	if (sc->sc_rbuf == NULL) {
494 		aprint_error_dev(sc->sc_dev,
495 		    "unable to allocate ring buffer\n");
496 		return;
497 	}
498 	sc->sc_ebuf = sc->sc_rbuf + (com_rbuf_size << 1);
499 
500 	tty_attach(tp);
501 
502 	if (!ISSET(sc->sc_hwflags, COM_HW_NOIEN))
503 		SET(sc->sc_mcr, MCR_IENABLE);
504 
505 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
506 		int maj;
507 
508 		/* locate the major number */
509 		maj = cdevsw_lookup_major(&com_cdevsw);
510 
511 		tp->t_dev = cn_tab->cn_dev = makedev(maj,
512 						     device_unit(sc->sc_dev));
513 
514 		aprint_normal_dev(sc->sc_dev, "console\n");
515 	}
516 
517 #ifdef KGDB
518 	/*
519 	 * Allow kgdb to "take over" this port.  If this is
520 	 * not the console and is the kgdb device, it has
521 	 * exclusive use.  If it's the console _and_ the
522 	 * kgdb device, it doesn't.
523 	 */
524 	if (regsp->cr_iot == comkgdbregs.cr_iot &&
525 	    regsp->cr_iobase == comkgdbregs.cr_iobase) {
526 		if (!ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
527 			com_kgdb_attached = 1;
528 
529 			SET(sc->sc_hwflags, COM_HW_KGDB);
530 		}
531 		aprint_normal_dev(sc->sc_dev, "kgdb\n");
532 	}
533 #endif
534 
535 	sc->sc_si = softint_establish(SOFTINT_SERIAL, comsoft, sc);
536 
537 #if NRND > 0 && defined(RND_COM)
538 	rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
539 			  RND_TYPE_TTY, 0);
540 #endif
541 
542 	/* if there are no enable/disable functions, assume the device
543 	   is always enabled */
544 	if (!sc->enable)
545 		sc->enabled = 1;
546 
547 	com_config(sc);
548 
549 	SET(sc->sc_hwflags, COM_HW_DEV_OK);
550 }
551 
552 void
553 com_config(struct com_softc *sc)
554 {
555 	struct com_regs *regsp = &sc->sc_regs;
556 
557 	/* Disable interrupts before configuring the device. */
558 	if (sc->sc_type == COM_TYPE_PXA2x0)
559 		sc->sc_ier = IER_EUART;
560 	else
561 		sc->sc_ier = 0;
562 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
563 	(void) CSR_READ_1(regsp, COM_REG_IIR);
564 
565 #ifdef COM_HAYESP
566 	/* Look for a Hayes ESP board. */
567 	if (sc->sc_type == COM_TYPE_HAYESP) {
568 
569 		/* Set 16550 compatibility mode */
570 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
571 				  HAYESP_SETMODE);
572 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
573 				  HAYESP_MODE_FIFO|HAYESP_MODE_RTS|
574 				  HAYESP_MODE_SCALE);
575 
576 		/* Set RTS/CTS flow control */
577 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
578 				  HAYESP_SETFLOWTYPE);
579 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
580 				  HAYESP_FLOW_RTS);
581 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
582 				  HAYESP_FLOW_CTS);
583 
584 		/* Set flow control levels */
585 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
586 				  HAYESP_SETRXFLOW);
587 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
588 				  HAYESP_HIBYTE(HAYESP_RXHIWMARK));
589 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
590 				  HAYESP_LOBYTE(HAYESP_RXHIWMARK));
591 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
592 				  HAYESP_HIBYTE(HAYESP_RXLOWMARK));
593 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
594 				  HAYESP_LOBYTE(HAYESP_RXLOWMARK));
595 	}
596 #endif
597 
598 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE|COM_HW_KGDB))
599 		com_enable_debugport(sc);
600 }
601 
602 int
603 com_detach(device_t self, int flags)
604 {
605 	struct com_softc *sc = device_private(self);
606 	int maj, mn;
607 
608         if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE))
609 		return EBUSY;
610 
611 	/* locate the major number */
612 	maj = cdevsw_lookup_major(&com_cdevsw);
613 
614 	/* Nuke the vnodes for any open instances. */
615 	mn = device_unit(self);
616 	vdevgone(maj, mn, mn, VCHR);
617 
618 	mn |= COMDIALOUT_MASK;
619 	vdevgone(maj, mn, mn, VCHR);
620 
621 	if (sc->sc_rbuf == NULL) {
622 		/*
623 		 * Ring buffer allocation failed in the com_attach_subr,
624 		 * only the tty is allocated, and nothing else.
625 		 */
626 		ttyfree(sc->sc_tty);
627 		return 0;
628 	}
629 
630 	/* Free the receive buffer. */
631 	free(sc->sc_rbuf, M_DEVBUF);
632 
633 	/* Detach and free the tty. */
634 	tty_detach(sc->sc_tty);
635 	ttyfree(sc->sc_tty);
636 
637 	/* Unhook the soft interrupt handler. */
638 	softint_disestablish(sc->sc_si);
639 
640 #if NRND > 0 && defined(RND_COM)
641 	/* Unhook the entropy source. */
642 	rnd_detach_source(&sc->rnd_source);
643 #endif
644 	callout_destroy(&sc->sc_diag_callout);
645 
646 	/* Destroy the lock. */
647 	mutex_destroy(&sc->sc_lock);
648 
649 	return (0);
650 }
651 
652 int
653 com_activate(device_t self, enum devact act)
654 {
655 	struct com_softc *sc = device_private(self);
656 	int rv = 0;
657 
658 	switch (act) {
659 	case DVACT_ACTIVATE:
660 		rv = EOPNOTSUPP;
661 		break;
662 
663 	case DVACT_DEACTIVATE:
664 		if (sc->sc_hwflags & (COM_HW_CONSOLE|COM_HW_KGDB)) {
665 			rv = EBUSY;
666 			break;
667 		}
668 
669 		if (sc->disable != NULL && sc->enabled != 0) {
670 			(*sc->disable)(sc);
671 			sc->enabled = 0;
672 		}
673 		break;
674 	}
675 
676 	return (rv);
677 }
678 
679 void
680 com_shutdown(struct com_softc *sc)
681 {
682 	struct tty *tp = sc->sc_tty;
683 
684 	mutex_spin_enter(&sc->sc_lock);
685 
686 	/* If we were asserting flow control, then deassert it. */
687 	SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
688 	com_hwiflow(sc);
689 
690 	/* Clear any break condition set with TIOCSBRK. */
691 	com_break(sc, 0);
692 
693 	/*
694 	 * Hang up if necessary.  Wait a bit, so the other side has time to
695 	 * notice even if we immediately open the port again.
696 	 * Avoid tsleeping above splhigh().
697 	 */
698 	if (ISSET(tp->t_cflag, HUPCL)) {
699 		com_modem(sc, 0);
700 		mutex_spin_exit(&sc->sc_lock);
701 		/* XXX will only timeout */
702 		(void) kpause(ttclos, false, hz, NULL);
703 		mutex_spin_enter(&sc->sc_lock);
704 	}
705 
706 	/* Turn off interrupts. */
707 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
708 		sc->sc_ier = IER_ERXRDY; /* interrupt on break */
709 		if (sc->sc_type == COM_TYPE_PXA2x0)
710 			sc->sc_ier |= IER_ERXTOUT;
711 	} else
712 		sc->sc_ier = 0;
713 
714 	if (sc->sc_type == COM_TYPE_PXA2x0)
715 		sc->sc_ier |= IER_EUART;
716 
717 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
718 
719 	mutex_spin_exit(&sc->sc_lock);
720 
721 	if (sc->disable) {
722 #ifdef DIAGNOSTIC
723 		if (!sc->enabled)
724 			panic("com_shutdown: not enabled?");
725 #endif
726 		(*sc->disable)(sc);
727 		sc->enabled = 0;
728 	}
729 }
730 
731 int
732 comopen(dev_t dev, int flag, int mode, struct lwp *l)
733 {
734 	struct com_softc *sc;
735 	struct tty *tp;
736 	int s;
737 	int error;
738 
739 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
740 	if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK) ||
741 		sc->sc_rbuf == NULL)
742 		return (ENXIO);
743 
744 	if (!device_is_active(sc->sc_dev))
745 		return (ENXIO);
746 
747 #ifdef KGDB
748 	/*
749 	 * If this is the kgdb port, no other use is permitted.
750 	 */
751 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
752 		return (EBUSY);
753 #endif
754 
755 	tp = sc->sc_tty;
756 
757 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
758 		return (EBUSY);
759 
760 	s = spltty();
761 
762 	/*
763 	 * Do the following iff this is a first open.
764 	 */
765 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
766 		struct termios t;
767 
768 		tp->t_dev = dev;
769 
770 
771 		if (sc->enable) {
772 			if ((*sc->enable)(sc)) {
773 				splx(s);
774 				aprint_error_dev(sc->sc_dev,
775 				    "device enable failed\n");
776 				return (EIO);
777 			}
778 			mutex_spin_enter(&sc->sc_lock);
779 			sc->enabled = 1;
780 			com_config(sc);
781 		} else {
782 			mutex_spin_enter(&sc->sc_lock);
783 		}
784 
785 		/* Turn on interrupts. */
786 		sc->sc_ier = IER_ERXRDY | IER_ERLS | IER_EMSC;
787 		if (sc->sc_type == COM_TYPE_PXA2x0)
788 			sc->sc_ier |= IER_EUART | IER_ERXTOUT;
789 		CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
790 
791 		/* Fetch the current modem control status, needed later. */
792 		sc->sc_msr = CSR_READ_1(&sc->sc_regs, COM_REG_MSR);
793 
794 		/* Clear PPS capture state on first open. */
795 		mutex_spin_enter(&timecounter_lock);
796 		memset(&sc->sc_pps_state, 0, sizeof(sc->sc_pps_state));
797 		sc->sc_pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
798 		pps_init(&sc->sc_pps_state);
799 		mutex_spin_exit(&timecounter_lock);
800 
801 		mutex_spin_exit(&sc->sc_lock);
802 
803 		/*
804 		 * Initialize the termios status to the defaults.  Add in the
805 		 * sticky bits from TIOCSFLAGS.
806 		 */
807 		if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
808 			t.c_ospeed = comconsrate;
809 			t.c_cflag = comconscflag;
810 		} else {
811 			t.c_ospeed = TTYDEF_SPEED;
812 			t.c_cflag = TTYDEF_CFLAG;
813 		}
814 		t.c_ispeed = t.c_ospeed;
815 		if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
816 			SET(t.c_cflag, CLOCAL);
817 		if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
818 			SET(t.c_cflag, CRTSCTS);
819 		if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
820 			SET(t.c_cflag, MDMBUF);
821 		/* Make sure comparam() will do something. */
822 		tp->t_ospeed = 0;
823 		(void) comparam(tp, &t);
824 		tp->t_iflag = TTYDEF_IFLAG;
825 		tp->t_oflag = TTYDEF_OFLAG;
826 		tp->t_lflag = TTYDEF_LFLAG;
827 		ttychars(tp);
828 		ttsetwater(tp);
829 
830 		mutex_spin_enter(&sc->sc_lock);
831 
832 		/*
833 		 * Turn on DTR.  We must always do this, even if carrier is not
834 		 * present, because otherwise we'd have to use TIOCSDTR
835 		 * immediately after setting CLOCAL, which applications do not
836 		 * expect.  We always assert DTR while the device is open
837 		 * unless explicitly requested to deassert it.
838 		 */
839 		com_modem(sc, 1);
840 
841 		/* Clear the input ring, and unblock. */
842 		sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
843 		sc->sc_rbavail = com_rbuf_size;
844 		com_iflush(sc);
845 		CLR(sc->sc_rx_flags, RX_ANY_BLOCK);
846 		com_hwiflow(sc);
847 
848 #ifdef COM_DEBUG
849 		if (com_debug)
850 			comstatus(sc, "comopen  ");
851 #endif
852 
853 		mutex_spin_exit(&sc->sc_lock);
854 	}
855 
856 	splx(s);
857 
858 	error = ttyopen(tp, COMDIALOUT(dev), ISSET(flag, O_NONBLOCK));
859 	if (error)
860 		goto bad;
861 
862 	error = (*tp->t_linesw->l_open)(dev, tp);
863 	if (error)
864 		goto bad;
865 
866 	return (0);
867 
868 bad:
869 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
870 		/*
871 		 * We failed to open the device, and nobody else had it opened.
872 		 * Clean up the state as appropriate.
873 		 */
874 		com_shutdown(sc);
875 	}
876 
877 	return (error);
878 }
879 
880 int
881 comclose(dev_t dev, int flag, int mode, struct lwp *l)
882 {
883 	struct com_softc *sc =
884 	    device_lookup_private(&com_cd, COMUNIT(dev));
885 	struct tty *tp = sc->sc_tty;
886 
887 	/* XXX This is for cons.c. */
888 	if (!ISSET(tp->t_state, TS_ISOPEN))
889 		return (0);
890 
891 	(*tp->t_linesw->l_close)(tp, flag);
892 	ttyclose(tp);
893 
894 	if (COM_ISALIVE(sc) == 0)
895 		return (0);
896 
897 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
898 		/*
899 		 * Although we got a last close, the device may still be in
900 		 * use; e.g. if this was the dialout node, and there are still
901 		 * processes waiting for carrier on the non-dialout node.
902 		 */
903 		com_shutdown(sc);
904 	}
905 
906 	return (0);
907 }
908 
909 int
910 comread(dev_t dev, struct uio *uio, int flag)
911 {
912 	struct com_softc *sc =
913 	    device_lookup_private(&com_cd, COMUNIT(dev));
914 	struct tty *tp = sc->sc_tty;
915 
916 	if (COM_ISALIVE(sc) == 0)
917 		return (EIO);
918 
919 	return ((*tp->t_linesw->l_read)(tp, uio, flag));
920 }
921 
922 int
923 comwrite(dev_t dev, struct uio *uio, int flag)
924 {
925 	struct com_softc *sc =
926 	    device_lookup_private(&com_cd, COMUNIT(dev));
927 	struct tty *tp = sc->sc_tty;
928 
929 	if (COM_ISALIVE(sc) == 0)
930 		return (EIO);
931 
932 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
933 }
934 
935 int
936 compoll(dev_t dev, int events, struct lwp *l)
937 {
938 	struct com_softc *sc =
939 	    device_lookup_private(&com_cd, COMUNIT(dev));
940 	struct tty *tp = sc->sc_tty;
941 
942 	if (COM_ISALIVE(sc) == 0)
943 		return (POLLHUP);
944 
945 	return ((*tp->t_linesw->l_poll)(tp, events, l));
946 }
947 
948 struct tty *
949 comtty(dev_t dev)
950 {
951 	struct com_softc *sc =
952 	    device_lookup_private(&com_cd, COMUNIT(dev));
953 	struct tty *tp = sc->sc_tty;
954 
955 	return (tp);
956 }
957 
958 int
959 comioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
960 {
961 	struct com_softc *sc;
962 	struct tty *tp;
963 	int error;
964 
965 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
966 	if (sc == NULL)
967 		return ENXIO;
968 	if (COM_ISALIVE(sc) == 0)
969 		return (EIO);
970 
971 	tp = sc->sc_tty;
972 
973 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
974 	if (error != EPASSTHROUGH)
975 		return (error);
976 
977 	error = ttioctl(tp, cmd, data, flag, l);
978 	if (error != EPASSTHROUGH)
979 		return (error);
980 
981 	error = 0;
982 	switch (cmd) {
983 	case TIOCSFLAGS:
984 		error = kauth_authorize_device_tty(l->l_cred,
985 		    KAUTH_DEVICE_TTY_PRIVSET, tp);
986 		break;
987 	default:
988 		/* nothing */
989 		break;
990 	}
991 	if (error) {
992 		return error;
993 	}
994 
995 	mutex_spin_enter(&sc->sc_lock);
996 
997 	switch (cmd) {
998 	case TIOCSBRK:
999 		com_break(sc, 1);
1000 		break;
1001 
1002 	case TIOCCBRK:
1003 		com_break(sc, 0);
1004 		break;
1005 
1006 	case TIOCSDTR:
1007 		com_modem(sc, 1);
1008 		break;
1009 
1010 	case TIOCCDTR:
1011 		com_modem(sc, 0);
1012 		break;
1013 
1014 	case TIOCGFLAGS:
1015 		*(int *)data = sc->sc_swflags;
1016 		break;
1017 
1018 	case TIOCSFLAGS:
1019 		sc->sc_swflags = *(int *)data;
1020 		break;
1021 
1022 	case TIOCMSET:
1023 	case TIOCMBIS:
1024 	case TIOCMBIC:
1025 		tiocm_to_com(sc, cmd, *(int *)data);
1026 		break;
1027 
1028 	case TIOCMGET:
1029 		*(int *)data = com_to_tiocm(sc);
1030 		break;
1031 
1032 	case PPS_IOC_CREATE:
1033 	case PPS_IOC_DESTROY:
1034 	case PPS_IOC_GETPARAMS:
1035 	case PPS_IOC_SETPARAMS:
1036 	case PPS_IOC_GETCAP:
1037 	case PPS_IOC_FETCH:
1038 #ifdef PPS_SYNC
1039 	case PPS_IOC_KCBIND:
1040 #endif
1041 		mutex_spin_enter(&timecounter_lock);
1042 		error = pps_ioctl(cmd, data, &sc->sc_pps_state);
1043 		mutex_spin_exit(&timecounter_lock);
1044 		break;
1045 
1046 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
1047 		mutex_spin_enter(&timecounter_lock);
1048 #ifndef PPS_TRAILING_EDGE
1049 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1050 		    &sc->sc_pps_state.ppsinfo.assert_timestamp);
1051 #else
1052 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1053 		    &sc->sc_pps_state.ppsinfo.clear_timestamp);
1054 #endif
1055 		mutex_spin_exit(&timecounter_lock);
1056 		break;
1057 
1058 	default:
1059 		error = EPASSTHROUGH;
1060 		break;
1061 	}
1062 
1063 	mutex_spin_exit(&sc->sc_lock);
1064 
1065 #ifdef COM_DEBUG
1066 	if (com_debug)
1067 		comstatus(sc, "comioctl ");
1068 #endif
1069 
1070 	return (error);
1071 }
1072 
1073 integrate void
1074 com_schedrx(struct com_softc *sc)
1075 {
1076 
1077 	sc->sc_rx_ready = 1;
1078 
1079 	/* Wake up the poller. */
1080 	softint_schedule(sc->sc_si);
1081 }
1082 
1083 void
1084 com_break(struct com_softc *sc, int onoff)
1085 {
1086 
1087 	if (onoff)
1088 		SET(sc->sc_lcr, LCR_SBREAK);
1089 	else
1090 		CLR(sc->sc_lcr, LCR_SBREAK);
1091 
1092 	if (!sc->sc_heldchange) {
1093 		if (sc->sc_tx_busy) {
1094 			sc->sc_heldtbc = sc->sc_tbc;
1095 			sc->sc_tbc = 0;
1096 			sc->sc_heldchange = 1;
1097 		} else
1098 			com_loadchannelregs(sc);
1099 	}
1100 }
1101 
1102 void
1103 com_modem(struct com_softc *sc, int onoff)
1104 {
1105 
1106 	if (sc->sc_mcr_dtr == 0)
1107 		return;
1108 
1109 	if (onoff)
1110 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1111 	else
1112 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1113 
1114 	if (!sc->sc_heldchange) {
1115 		if (sc->sc_tx_busy) {
1116 			sc->sc_heldtbc = sc->sc_tbc;
1117 			sc->sc_tbc = 0;
1118 			sc->sc_heldchange = 1;
1119 		} else
1120 			com_loadchannelregs(sc);
1121 	}
1122 }
1123 
1124 void
1125 tiocm_to_com(struct com_softc *sc, u_long how, int ttybits)
1126 {
1127 	u_char combits;
1128 
1129 	combits = 0;
1130 	if (ISSET(ttybits, TIOCM_DTR))
1131 		SET(combits, MCR_DTR);
1132 	if (ISSET(ttybits, TIOCM_RTS))
1133 		SET(combits, MCR_RTS);
1134 
1135 	switch (how) {
1136 	case TIOCMBIC:
1137 		CLR(sc->sc_mcr, combits);
1138 		break;
1139 
1140 	case TIOCMBIS:
1141 		SET(sc->sc_mcr, combits);
1142 		break;
1143 
1144 	case TIOCMSET:
1145 		CLR(sc->sc_mcr, MCR_DTR | MCR_RTS);
1146 		SET(sc->sc_mcr, combits);
1147 		break;
1148 	}
1149 
1150 	if (!sc->sc_heldchange) {
1151 		if (sc->sc_tx_busy) {
1152 			sc->sc_heldtbc = sc->sc_tbc;
1153 			sc->sc_tbc = 0;
1154 			sc->sc_heldchange = 1;
1155 		} else
1156 			com_loadchannelregs(sc);
1157 	}
1158 }
1159 
1160 int
1161 com_to_tiocm(struct com_softc *sc)
1162 {
1163 	u_char combits;
1164 	int ttybits = 0;
1165 
1166 	combits = sc->sc_mcr;
1167 	if (ISSET(combits, MCR_DTR))
1168 		SET(ttybits, TIOCM_DTR);
1169 	if (ISSET(combits, MCR_RTS))
1170 		SET(ttybits, TIOCM_RTS);
1171 
1172 	combits = sc->sc_msr;
1173 	if (ISSET(combits, MSR_DCD))
1174 		SET(ttybits, TIOCM_CD);
1175 	if (ISSET(combits, MSR_CTS))
1176 		SET(ttybits, TIOCM_CTS);
1177 	if (ISSET(combits, MSR_DSR))
1178 		SET(ttybits, TIOCM_DSR);
1179 	if (ISSET(combits, MSR_RI | MSR_TERI))
1180 		SET(ttybits, TIOCM_RI);
1181 
1182 	if (ISSET(sc->sc_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS | IER_EMSC))
1183 		SET(ttybits, TIOCM_LE);
1184 
1185 	return (ttybits);
1186 }
1187 
1188 static u_char
1189 cflag2lcr(tcflag_t cflag)
1190 {
1191 	u_char lcr = 0;
1192 
1193 	switch (ISSET(cflag, CSIZE)) {
1194 	case CS5:
1195 		SET(lcr, LCR_5BITS);
1196 		break;
1197 	case CS6:
1198 		SET(lcr, LCR_6BITS);
1199 		break;
1200 	case CS7:
1201 		SET(lcr, LCR_7BITS);
1202 		break;
1203 	case CS8:
1204 		SET(lcr, LCR_8BITS);
1205 		break;
1206 	}
1207 	if (ISSET(cflag, PARENB)) {
1208 		SET(lcr, LCR_PENAB);
1209 		if (!ISSET(cflag, PARODD))
1210 			SET(lcr, LCR_PEVEN);
1211 	}
1212 	if (ISSET(cflag, CSTOPB))
1213 		SET(lcr, LCR_STOPB);
1214 
1215 	return (lcr);
1216 }
1217 
1218 int
1219 comparam(struct tty *tp, struct termios *t)
1220 {
1221 	struct com_softc *sc =
1222 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1223 	int ospeed;
1224 	u_char lcr;
1225 
1226 	if (COM_ISALIVE(sc) == 0)
1227 		return (EIO);
1228 
1229 #ifdef COM_HAYESP
1230 	if (sc->sc_type == COM_TYPE_HAYESP) {
1231 		int prescaler, speed;
1232 
1233 		/*
1234 		 * Calculate UART clock prescaler.  It should be in
1235 		 * range of 0 .. 3.
1236 		 */
1237 		for (prescaler = 0, speed = t->c_ospeed; prescaler < 4;
1238 		    prescaler++, speed /= 2)
1239 			if ((ospeed = comspeed(speed, sc->sc_frequency,
1240 					       sc->sc_type)) > 0)
1241 				break;
1242 
1243 		if (prescaler == 4)
1244 			return (EINVAL);
1245 		sc->sc_prescaler = prescaler;
1246 	} else
1247 #endif
1248 	ospeed = comspeed(t->c_ospeed, sc->sc_frequency, sc->sc_type);
1249 
1250 	/* Check requested parameters. */
1251 	if (ospeed < 0)
1252 		return (EINVAL);
1253 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
1254 		return (EINVAL);
1255 
1256 	/*
1257 	 * For the console, always force CLOCAL and !HUPCL, so that the port
1258 	 * is always active.
1259 	 */
1260 	if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
1261 	    ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
1262 		SET(t->c_cflag, CLOCAL);
1263 		CLR(t->c_cflag, HUPCL);
1264 	}
1265 
1266 	/*
1267 	 * If there were no changes, don't do anything.  This avoids dropping
1268 	 * input and improves performance when all we did was frob things like
1269 	 * VMIN and VTIME.
1270 	 */
1271 	if (tp->t_ospeed == t->c_ospeed &&
1272 	    tp->t_cflag == t->c_cflag)
1273 		return (0);
1274 
1275 	lcr = ISSET(sc->sc_lcr, LCR_SBREAK) | cflag2lcr(t->c_cflag);
1276 
1277 	mutex_spin_enter(&sc->sc_lock);
1278 
1279 	sc->sc_lcr = lcr;
1280 
1281 	/*
1282 	 * If we're not in a mode that assumes a connection is present, then
1283 	 * ignore carrier changes.
1284 	 */
1285 	if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
1286 		sc->sc_msr_dcd = 0;
1287 	else
1288 		sc->sc_msr_dcd = MSR_DCD;
1289 	/*
1290 	 * Set the flow control pins depending on the current flow control
1291 	 * mode.
1292 	 */
1293 	if (ISSET(t->c_cflag, CRTSCTS)) {
1294 		sc->sc_mcr_dtr = MCR_DTR;
1295 		sc->sc_mcr_rts = MCR_RTS;
1296 		sc->sc_msr_cts = MSR_CTS;
1297 		sc->sc_efr = EFR_AUTORTS | EFR_AUTOCTS;
1298 	} else if (ISSET(t->c_cflag, MDMBUF)) {
1299 		/*
1300 		 * For DTR/DCD flow control, make sure we don't toggle DTR for
1301 		 * carrier detection.
1302 		 */
1303 		sc->sc_mcr_dtr = 0;
1304 		sc->sc_mcr_rts = MCR_DTR;
1305 		sc->sc_msr_cts = MSR_DCD;
1306 		sc->sc_efr = 0;
1307 	} else {
1308 		/*
1309 		 * If no flow control, then always set RTS.  This will make
1310 		 * the other side happy if it mistakenly thinks we're doing
1311 		 * RTS/CTS flow control.
1312 		 */
1313 		sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
1314 		sc->sc_mcr_rts = 0;
1315 		sc->sc_msr_cts = 0;
1316 		sc->sc_efr = 0;
1317 		if (ISSET(sc->sc_mcr, MCR_DTR))
1318 			SET(sc->sc_mcr, MCR_RTS);
1319 		else
1320 			CLR(sc->sc_mcr, MCR_RTS);
1321 	}
1322 	sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;
1323 
1324 #if 0
1325 	if (ospeed == 0)
1326 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1327 	else
1328 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1329 #endif
1330 
1331 	sc->sc_dlbl = ospeed;
1332 	sc->sc_dlbh = ospeed >> 8;
1333 
1334 	/*
1335 	 * Set the FIFO threshold based on the receive speed.
1336 	 *
1337 	 *  * If it's a low speed, it's probably a mouse or some other
1338 	 *    interactive device, so set the threshold low.
1339 	 *  * If it's a high speed, trim the trigger level down to prevent
1340 	 *    overflows.
1341 	 *  * Otherwise set it a bit higher.
1342 	 */
1343 	if (sc->sc_type == COM_TYPE_HAYESP)
1344 		sc->sc_fifo = FIFO_DMA_MODE | FIFO_ENABLE | FIFO_TRIGGER_8;
1345 	else if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
1346 		if (t->c_ospeed <= 1200)
1347 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
1348 		else if (t->c_ospeed <= 38400)
1349 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_8;
1350 		else
1351 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_4;
1352 	} else
1353 		sc->sc_fifo = 0;
1354 
1355 	/* And copy to tty. */
1356 	tp->t_ispeed = t->c_ospeed;
1357 	tp->t_ospeed = t->c_ospeed;
1358 	tp->t_cflag = t->c_cflag;
1359 
1360 	if (!sc->sc_heldchange) {
1361 		if (sc->sc_tx_busy) {
1362 			sc->sc_heldtbc = sc->sc_tbc;
1363 			sc->sc_tbc = 0;
1364 			sc->sc_heldchange = 1;
1365 		} else
1366 			com_loadchannelregs(sc);
1367 	}
1368 
1369 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1370 		/* Disable the high water mark. */
1371 		sc->sc_r_hiwat = 0;
1372 		sc->sc_r_lowat = 0;
1373 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1374 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1375 			com_schedrx(sc);
1376 		}
1377 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
1378 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
1379 			com_hwiflow(sc);
1380 		}
1381 	} else {
1382 		sc->sc_r_hiwat = com_rbuf_hiwat;
1383 		sc->sc_r_lowat = com_rbuf_lowat;
1384 	}
1385 
1386 	mutex_spin_exit(&sc->sc_lock);
1387 
1388 	/*
1389 	 * Update the tty layer's idea of the carrier bit, in case we changed
1390 	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
1391 	 * explicit request.
1392 	 */
1393 	(void) (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, MSR_DCD));
1394 
1395 #ifdef COM_DEBUG
1396 	if (com_debug)
1397 		comstatus(sc, "comparam ");
1398 #endif
1399 
1400 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1401 		if (sc->sc_tx_stopped) {
1402 			sc->sc_tx_stopped = 0;
1403 			comstart(tp);
1404 		}
1405 	}
1406 
1407 	return (0);
1408 }
1409 
1410 void
1411 com_iflush(struct com_softc *sc)
1412 {
1413 	struct com_regs	*regsp = &sc->sc_regs;
1414 #ifdef DIAGNOSTIC
1415 	int reg;
1416 #endif
1417 	int timo;
1418 
1419 #ifdef DIAGNOSTIC
1420 	reg = 0xffff;
1421 #endif
1422 	timo = 50000;
1423 	/* flush any pending I/O */
1424 	while (ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)
1425 	    && --timo)
1426 #ifdef DIAGNOSTIC
1427 		reg =
1428 #else
1429 		    (void)
1430 #endif
1431 		    CSR_READ_1(regsp, COM_REG_RXDATA);
1432 #ifdef DIAGNOSTIC
1433 	if (!timo)
1434 		aprint_error_dev(sc->sc_dev, "com_iflush timeout %02x\n", reg);
1435 #endif
1436 }
1437 
1438 void
1439 com_loadchannelregs(struct com_softc *sc)
1440 {
1441 	struct com_regs *regsp = &sc->sc_regs;
1442 
1443 	/* XXXXX necessary? */
1444 	com_iflush(sc);
1445 
1446 	if (sc->sc_type == COM_TYPE_PXA2x0)
1447 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
1448 	else
1449 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
1450 
1451 	if (sc->sc_type == COM_TYPE_OMAP) {
1452 		/* disable before changing settings */
1453 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
1454 	}
1455 
1456 	if (ISSET(sc->sc_hwflags, COM_HW_FLOW)) {
1457 		if (sc->sc_type != COM_TYPE_AU1x00) {	/* no EFR on alchemy */
1458 			CSR_WRITE_1(regsp, COM_REG_EFR, sc->sc_efr);
1459 			CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
1460 		}
1461 	}
1462 	if (sc->sc_type == COM_TYPE_AU1x00) {
1463 		/* alchemy has single separate 16-bit clock divisor register */
1464 		CSR_WRITE_2(regsp, COM_REG_DLBL, sc->sc_dlbl +
1465 		    (sc->sc_dlbh << 8));
1466 	} else {
1467 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
1468 		CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
1469 		CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
1470 	}
1471 	CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
1472 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active = sc->sc_mcr);
1473 	CSR_WRITE_1(regsp, COM_REG_FIFO, sc->sc_fifo);
1474 #ifdef COM_HAYESP
1475 	if (sc->sc_type == COM_TYPE_HAYESP) {
1476 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
1477 		    HAYESP_SETPRESCALER);
1478 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
1479 		    sc->sc_prescaler);
1480 	}
1481 #endif
1482 	if (sc->sc_type == COM_TYPE_OMAP) {
1483 		/* setup the fifos.  the FCR value is not used as long
1484 		   as SCR[6] and SCR[7] are 0, which they are at reset
1485 		   and we never touch the SCR register */
1486 		uint8_t rx_fifo_trig = 40;
1487 		uint8_t tx_fifo_trig = 60;
1488 		uint8_t rx_start = 8;
1489 		uint8_t rx_halt = 60;
1490 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
1491 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
1492 
1493 		/* enable access to TCR & TLR */
1494 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr | MCR_TCR_TLR);
1495 
1496 		/* write tcr and tlr values */
1497 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
1498 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
1499 
1500 		/* disable access to TCR & TLR */
1501 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr);
1502 
1503 		/* enable again, but mode is based on speed */
1504 		if (sc->sc_tty->t_termios.c_ospeed > 230400) {
1505 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
1506 		} else {
1507 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
1508 		}
1509 	}
1510 
1511 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1512 }
1513 
1514 int
1515 comhwiflow(struct tty *tp, int block)
1516 {
1517 	struct com_softc *sc =
1518 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1519 
1520 	if (COM_ISALIVE(sc) == 0)
1521 		return (0);
1522 
1523 	if (sc->sc_mcr_rts == 0)
1524 		return (0);
1525 
1526 	mutex_spin_enter(&sc->sc_lock);
1527 
1528 	if (block) {
1529 		if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1530 			SET(sc->sc_rx_flags, RX_TTY_BLOCKED);
1531 			com_hwiflow(sc);
1532 		}
1533 	} else {
1534 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1535 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1536 			com_schedrx(sc);
1537 		}
1538 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1539 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED);
1540 			com_hwiflow(sc);
1541 		}
1542 	}
1543 
1544 	mutex_spin_exit(&sc->sc_lock);
1545 	return (1);
1546 }
1547 
1548 /*
1549  * (un)block input via hw flowcontrol
1550  */
1551 void
1552 com_hwiflow(struct com_softc *sc)
1553 {
1554 	struct com_regs *regsp= &sc->sc_regs;
1555 
1556 	if (sc->sc_mcr_rts == 0)
1557 		return;
1558 
1559 	if (ISSET(sc->sc_rx_flags, RX_ANY_BLOCK)) {
1560 		CLR(sc->sc_mcr, sc->sc_mcr_rts);
1561 		CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
1562 	} else {
1563 		SET(sc->sc_mcr, sc->sc_mcr_rts);
1564 		SET(sc->sc_mcr_active, sc->sc_mcr_rts);
1565 	}
1566 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active);
1567 }
1568 
1569 
1570 void
1571 comstart(struct tty *tp)
1572 {
1573 	struct com_softc *sc =
1574 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1575 	struct com_regs *regsp = &sc->sc_regs;
1576 	int s;
1577 
1578 	if (COM_ISALIVE(sc) == 0)
1579 		return;
1580 
1581 	s = spltty();
1582 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
1583 		goto out;
1584 	if (sc->sc_tx_stopped)
1585 		goto out;
1586 	if (!ttypull(tp))
1587 		goto out;
1588 
1589 	/* Grab the first contiguous region of buffer space. */
1590 	{
1591 		u_char *tba;
1592 		int tbc;
1593 
1594 		tba = tp->t_outq.c_cf;
1595 		tbc = ndqb(&tp->t_outq, 0);
1596 
1597 		mutex_spin_enter(&sc->sc_lock);
1598 
1599 		sc->sc_tba = tba;
1600 		sc->sc_tbc = tbc;
1601 	}
1602 
1603 	SET(tp->t_state, TS_BUSY);
1604 	sc->sc_tx_busy = 1;
1605 
1606 	/* Enable transmit completion interrupts if necessary. */
1607 	if (!ISSET(sc->sc_ier, IER_ETXRDY)) {
1608 		SET(sc->sc_ier, IER_ETXRDY);
1609 		CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1610 	}
1611 
1612 	/* Output the first chunk of the contiguous buffer. */
1613 	if (!ISSET(sc->sc_hwflags, COM_HW_NO_TXPRELOAD)) {
1614 		u_int n;
1615 
1616 		n = sc->sc_tbc;
1617 		if (n > sc->sc_fifolen)
1618 			n = sc->sc_fifolen;
1619 		CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
1620 		sc->sc_tbc -= n;
1621 		sc->sc_tba += n;
1622 	}
1623 
1624 	mutex_spin_exit(&sc->sc_lock);
1625 out:
1626 	splx(s);
1627 	return;
1628 }
1629 
1630 /*
1631  * Stop output on a line.
1632  */
1633 void
1634 comstop(struct tty *tp, int flag)
1635 {
1636 	struct com_softc *sc =
1637 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1638 
1639 	mutex_spin_enter(&sc->sc_lock);
1640 	if (ISSET(tp->t_state, TS_BUSY)) {
1641 		/* Stop transmitting at the next chunk. */
1642 		sc->sc_tbc = 0;
1643 		sc->sc_heldtbc = 0;
1644 		if (!ISSET(tp->t_state, TS_TTSTOP))
1645 			SET(tp->t_state, TS_FLUSH);
1646 	}
1647 	mutex_spin_exit(&sc->sc_lock);
1648 }
1649 
1650 void
1651 comdiag(void *arg)
1652 {
1653 	struct com_softc *sc = arg;
1654 	int overflows, floods;
1655 
1656 	mutex_spin_enter(&sc->sc_lock);
1657 	overflows = sc->sc_overflows;
1658 	sc->sc_overflows = 0;
1659 	floods = sc->sc_floods;
1660 	sc->sc_floods = 0;
1661 	sc->sc_errors = 0;
1662 	mutex_spin_exit(&sc->sc_lock);
1663 
1664 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
1665 	    device_xname(sc->sc_dev),
1666 	    overflows, overflows == 1 ? "" : "s",
1667 	    floods, floods == 1 ? "" : "s");
1668 }
1669 
1670 integrate void
1671 com_rxsoft(struct com_softc *sc, struct tty *tp)
1672 {
1673 	int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
1674 	u_char *get, *end;
1675 	u_int cc, scc;
1676 	u_char lsr;
1677 	int code;
1678 
1679 	end = sc->sc_ebuf;
1680 	get = sc->sc_rbget;
1681 	scc = cc = com_rbuf_size - sc->sc_rbavail;
1682 
1683 	if (cc == com_rbuf_size) {
1684 		sc->sc_floods++;
1685 		if (sc->sc_errors++ == 0)
1686 			callout_reset(&sc->sc_diag_callout, 60 * hz,
1687 			    comdiag, sc);
1688 	}
1689 
1690 	/* If not yet open, drop the entire buffer content here */
1691 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
1692 		get += cc << 1;
1693 		if (get >= end)
1694 			get -= com_rbuf_size << 1;
1695 		cc = 0;
1696 	}
1697 	while (cc) {
1698 		code = get[0];
1699 		lsr = get[1];
1700 		if (ISSET(lsr, LSR_OE | LSR_BI | LSR_FE | LSR_PE)) {
1701 			if (ISSET(lsr, LSR_OE)) {
1702 				sc->sc_overflows++;
1703 				if (sc->sc_errors++ == 0)
1704 					callout_reset(&sc->sc_diag_callout,
1705 					    60 * hz, comdiag, sc);
1706 			}
1707 			if (ISSET(lsr, LSR_BI | LSR_FE))
1708 				SET(code, TTY_FE);
1709 			if (ISSET(lsr, LSR_PE))
1710 				SET(code, TTY_PE);
1711 		}
1712 		if ((*rint)(code, tp) == -1) {
1713 			/*
1714 			 * The line discipline's buffer is out of space.
1715 			 */
1716 			if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1717 				/*
1718 				 * We're either not using flow control, or the
1719 				 * line discipline didn't tell us to block for
1720 				 * some reason.  Either way, we have no way to
1721 				 * know when there's more space available, so
1722 				 * just drop the rest of the data.
1723 				 */
1724 				get += cc << 1;
1725 				if (get >= end)
1726 					get -= com_rbuf_size << 1;
1727 				cc = 0;
1728 			} else {
1729 				/*
1730 				 * Don't schedule any more receive processing
1731 				 * until the line discipline tells us there's
1732 				 * space available (through comhwiflow()).
1733 				 * Leave the rest of the data in the input
1734 				 * buffer.
1735 				 */
1736 				SET(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1737 			}
1738 			break;
1739 		}
1740 		get += 2;
1741 		if (get >= end)
1742 			get = sc->sc_rbuf;
1743 		cc--;
1744 	}
1745 
1746 	if (cc != scc) {
1747 		sc->sc_rbget = get;
1748 		mutex_spin_enter(&sc->sc_lock);
1749 
1750 		cc = sc->sc_rbavail += scc - cc;
1751 		/* Buffers should be ok again, release possible block. */
1752 		if (cc >= sc->sc_r_lowat) {
1753 			if (ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
1754 				CLR(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
1755 				SET(sc->sc_ier, IER_ERXRDY);
1756 #ifdef COM_PXA2X0
1757 				if (sc->sc_type == COM_TYPE_PXA2x0)
1758 					SET(sc->sc_ier, IER_ERXTOUT);
1759 #endif
1760 				CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
1761 			}
1762 			if (ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED)) {
1763 				CLR(sc->sc_rx_flags, RX_IBUF_BLOCKED);
1764 				com_hwiflow(sc);
1765 			}
1766 		}
1767 		mutex_spin_exit(&sc->sc_lock);
1768 	}
1769 }
1770 
1771 integrate void
1772 com_txsoft(struct com_softc *sc, struct tty *tp)
1773 {
1774 
1775 	CLR(tp->t_state, TS_BUSY);
1776 	if (ISSET(tp->t_state, TS_FLUSH))
1777 		CLR(tp->t_state, TS_FLUSH);
1778 	else
1779 		ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
1780 	(*tp->t_linesw->l_start)(tp);
1781 }
1782 
1783 integrate void
1784 com_stsoft(struct com_softc *sc, struct tty *tp)
1785 {
1786 	u_char msr, delta;
1787 
1788 	mutex_spin_enter(&sc->sc_lock);
1789 	msr = sc->sc_msr;
1790 	delta = sc->sc_msr_delta;
1791 	sc->sc_msr_delta = 0;
1792 	mutex_spin_exit(&sc->sc_lock);
1793 
1794 	if (ISSET(delta, sc->sc_msr_dcd)) {
1795 		/*
1796 		 * Inform the tty layer that carrier detect changed.
1797 		 */
1798 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(msr, MSR_DCD));
1799 	}
1800 
1801 	if (ISSET(delta, sc->sc_msr_cts)) {
1802 		/* Block or unblock output according to flow control. */
1803 		if (ISSET(msr, sc->sc_msr_cts)) {
1804 			sc->sc_tx_stopped = 0;
1805 			(*tp->t_linesw->l_start)(tp);
1806 		} else {
1807 			sc->sc_tx_stopped = 1;
1808 		}
1809 	}
1810 
1811 #ifdef COM_DEBUG
1812 	if (com_debug)
1813 		comstatus(sc, "com_stsoft");
1814 #endif
1815 }
1816 
1817 void
1818 comsoft(void *arg)
1819 {
1820 	struct com_softc *sc = arg;
1821 	struct tty *tp;
1822 
1823 	if (COM_ISALIVE(sc) == 0)
1824 		return;
1825 
1826 	tp = sc->sc_tty;
1827 
1828 	if (sc->sc_rx_ready) {
1829 		sc->sc_rx_ready = 0;
1830 		com_rxsoft(sc, tp);
1831 	}
1832 
1833 	if (sc->sc_st_check) {
1834 		sc->sc_st_check = 0;
1835 		com_stsoft(sc, tp);
1836 	}
1837 
1838 	if (sc->sc_tx_done) {
1839 		sc->sc_tx_done = 0;
1840 		com_txsoft(sc, tp);
1841 	}
1842 }
1843 
1844 int
1845 comintr(void *arg)
1846 {
1847 	struct com_softc *sc = arg;
1848 	struct com_regs *regsp = &sc->sc_regs;
1849 
1850 	u_char *put, *end;
1851 	u_int cc;
1852 	u_char lsr, iir;
1853 
1854 	if (COM_ISALIVE(sc) == 0)
1855 		return (0);
1856 
1857 	mutex_spin_enter(&sc->sc_lock);
1858 	iir = CSR_READ_1(regsp, COM_REG_IIR);
1859 	if (ISSET(iir, IIR_NOPEND)) {
1860 		mutex_spin_exit(&sc->sc_lock);
1861 		return (0);
1862 	}
1863 
1864 	end = sc->sc_ebuf;
1865 	put = sc->sc_rbput;
1866 	cc = sc->sc_rbavail;
1867 
1868 again:	do {
1869 		u_char	msr, delta;
1870 
1871 		lsr = CSR_READ_1(regsp, COM_REG_LSR);
1872 		if (ISSET(lsr, LSR_BI)) {
1873 			int cn_trapped = 0;
1874 
1875 			cn_check_magic(sc->sc_tty->t_dev,
1876 				       CNC_BREAK, com_cnm_state);
1877 			if (cn_trapped)
1878 				continue;
1879 #if defined(KGDB) && !defined(DDB)
1880 			if (ISSET(sc->sc_hwflags, COM_HW_KGDB)) {
1881 				kgdb_connect(1);
1882 				continue;
1883 			}
1884 #endif
1885 		}
1886 
1887 		if (ISSET(lsr, LSR_RCV_MASK) &&
1888 		    !ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
1889 			while (cc > 0) {
1890 				int cn_trapped = 0;
1891 				put[0] = CSR_READ_1(regsp, COM_REG_RXDATA);
1892 				put[1] = lsr;
1893 				cn_check_magic(sc->sc_tty->t_dev,
1894 					       put[0], com_cnm_state);
1895 				if (cn_trapped)
1896 					goto next;
1897 				put += 2;
1898 				if (put >= end)
1899 					put = sc->sc_rbuf;
1900 				cc--;
1901 			next:
1902 				lsr = CSR_READ_1(regsp, COM_REG_LSR);
1903 				if (!ISSET(lsr, LSR_RCV_MASK))
1904 					break;
1905 			}
1906 
1907 			/*
1908 			 * Current string of incoming characters ended because
1909 			 * no more data was available or we ran out of space.
1910 			 * Schedule a receive event if any data was received.
1911 			 * If we're out of space, turn off receive interrupts.
1912 			 */
1913 			sc->sc_rbput = put;
1914 			sc->sc_rbavail = cc;
1915 			if (!ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED))
1916 				sc->sc_rx_ready = 1;
1917 
1918 			/*
1919 			 * See if we are in danger of overflowing a buffer. If
1920 			 * so, use hardware flow control to ease the pressure.
1921 			 */
1922 			if (!ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED) &&
1923 			    cc < sc->sc_r_hiwat) {
1924 				SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
1925 				com_hwiflow(sc);
1926 			}
1927 
1928 			/*
1929 			 * If we're out of space, disable receive interrupts
1930 			 * until the queue has drained a bit.
1931 			 */
1932 			if (!cc) {
1933 				SET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
1934 #ifdef COM_PXA2X0
1935 				if (sc->sc_type == COM_TYPE_PXA2x0)
1936 					CLR(sc->sc_ier, IER_ERXRDY|IER_ERXTOUT);
1937 				else
1938 #endif
1939 					CLR(sc->sc_ier, IER_ERXRDY);
1940 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1941 			}
1942 		} else {
1943 			if ((iir & (IIR_RXRDY|IIR_TXRDY)) == IIR_RXRDY) {
1944 				(void) CSR_READ_1(regsp, COM_REG_RXDATA);
1945 				continue;
1946 			}
1947 		}
1948 
1949 		msr = CSR_READ_1(regsp, COM_REG_MSR);
1950 		delta = msr ^ sc->sc_msr;
1951 		sc->sc_msr = msr;
1952 		if ((sc->sc_pps_state.ppsparam.mode & PPS_CAPTUREBOTH) &&
1953 		    (delta & MSR_DCD)) {
1954 			mutex_spin_enter(&timecounter_lock);
1955 			pps_capture(&sc->sc_pps_state);
1956 			pps_event(&sc->sc_pps_state,
1957 			    (msr & MSR_DCD) ?
1958 			    PPS_CAPTUREASSERT :
1959 			    PPS_CAPTURECLEAR);
1960 			mutex_spin_exit(&timecounter_lock);
1961 		}
1962 
1963 		/*
1964 		 * Process normal status changes
1965 		 */
1966 		if (ISSET(delta, sc->sc_msr_mask)) {
1967 			SET(sc->sc_msr_delta, delta);
1968 
1969 			/*
1970 			 * Stop output immediately if we lose the output
1971 			 * flow control signal or carrier detect.
1972 			 */
1973 			if (ISSET(~msr, sc->sc_msr_mask)) {
1974 				sc->sc_tbc = 0;
1975 				sc->sc_heldtbc = 0;
1976 #ifdef COM_DEBUG
1977 				if (com_debug)
1978 					comstatus(sc, "comintr  ");
1979 #endif
1980 			}
1981 
1982 			sc->sc_st_check = 1;
1983 		}
1984 	} while (!ISSET((iir =
1985 	    CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND) &&
1986 	    /*
1987 	     * Since some device (e.g., ST16C1550) doesn't clear IIR_TXRDY
1988 	     * by IIR read, so we can't do this way: `process all interrupts,
1989 	     * then do TX if possble'.
1990 	     */
1991 	    (iir & IIR_IMASK) != IIR_TXRDY);
1992 
1993 	/*
1994 	 * Read LSR again, since there may be an interrupt between
1995 	 * the last LSR read and IIR read above.
1996 	 */
1997 	lsr = CSR_READ_1(regsp, COM_REG_LSR);
1998 
1999 	/*
2000 	 * See if data can be transmitted as well.
2001 	 * Schedule tx done event if no data left
2002 	 * and tty was marked busy.
2003 	 */
2004 	if (ISSET(lsr, LSR_TXRDY)) {
2005 		/*
2006 		 * If we've delayed a parameter change, do it now, and restart
2007 		 * output.
2008 		 */
2009 		if (sc->sc_heldchange) {
2010 			com_loadchannelregs(sc);
2011 			sc->sc_heldchange = 0;
2012 			sc->sc_tbc = sc->sc_heldtbc;
2013 			sc->sc_heldtbc = 0;
2014 		}
2015 
2016 		/* Output the next chunk of the contiguous buffer, if any. */
2017 		if (sc->sc_tbc > 0) {
2018 			u_int n;
2019 
2020 			n = sc->sc_tbc;
2021 			if (n > sc->sc_fifolen)
2022 				n = sc->sc_fifolen;
2023 			CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
2024 			sc->sc_tbc -= n;
2025 			sc->sc_tba += n;
2026 		} else {
2027 			/* Disable transmit completion interrupts if necessary. */
2028 			if (ISSET(sc->sc_ier, IER_ETXRDY)) {
2029 				CLR(sc->sc_ier, IER_ETXRDY);
2030 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
2031 			}
2032 			if (sc->sc_tx_busy) {
2033 				sc->sc_tx_busy = 0;
2034 				sc->sc_tx_done = 1;
2035 			}
2036 		}
2037 	}
2038 
2039 	if (!ISSET((iir = CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND))
2040 		goto again;
2041 
2042 	mutex_spin_exit(&sc->sc_lock);
2043 
2044 	/* Wake up the poller. */
2045 	softint_schedule(sc->sc_si);
2046 
2047 #if NRND > 0 && defined(RND_COM)
2048 	rnd_add_uint32(&sc->rnd_source, iir | lsr);
2049 #endif
2050 
2051 	return (1);
2052 }
2053 
2054 /*
2055  * The following functions are polled getc and putc routines, shared
2056  * by the console and kgdb glue.
2057  *
2058  * The read-ahead code is so that you can detect pending in-band
2059  * cn_magic in polled mode while doing output rather than having to
2060  * wait until the kernel decides it needs input.
2061  */
2062 
2063 #define MAX_READAHEAD	20
2064 static int com_readahead[MAX_READAHEAD];
2065 static int com_readaheadcount = 0;
2066 
2067 int
2068 com_common_getc(dev_t dev, struct com_regs *regsp)
2069 {
2070 	int s = splserial();
2071 	u_char stat, c;
2072 
2073 	/* got a character from reading things earlier */
2074 	if (com_readaheadcount > 0) {
2075 		int i;
2076 
2077 		c = com_readahead[0];
2078 		for (i = 1; i < com_readaheadcount; i++) {
2079 			com_readahead[i-1] = com_readahead[i];
2080 		}
2081 		com_readaheadcount--;
2082 		splx(s);
2083 		return (c);
2084 	}
2085 
2086 	/* block until a character becomes available */
2087 	while (!ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY))
2088 		;
2089 
2090 	c = CSR_READ_1(regsp, COM_REG_RXDATA);
2091 	stat = CSR_READ_1(regsp, COM_REG_IIR);
2092 	{
2093 		int cn_trapped = 0; /* unused */
2094 #ifdef DDB
2095 		extern int db_active;
2096 		if (!db_active)
2097 #endif
2098 			cn_check_magic(dev, c, com_cnm_state);
2099 	}
2100 	splx(s);
2101 	return (c);
2102 }
2103 
2104 void
2105 com_common_putc(dev_t dev, struct com_regs *regsp, int c)
2106 {
2107 	int s = splserial();
2108 	int cin, stat, timo;
2109 
2110 	if (com_readaheadcount < MAX_READAHEAD
2111 	     && ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
2112 		int cn_trapped = 0;
2113 		cin = CSR_READ_1(regsp, COM_REG_RXDATA);
2114 		stat = CSR_READ_1(regsp, COM_REG_IIR);
2115 		cn_check_magic(dev, cin, com_cnm_state);
2116 		com_readahead[com_readaheadcount++] = cin;
2117 	}
2118 
2119 	/* wait for any pending transmission to finish */
2120 	timo = 150000;
2121 	while (!ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_TXRDY) && --timo)
2122 		continue;
2123 
2124 	CSR_WRITE_1(regsp, COM_REG_TXDATA, c);
2125 	COM_BARRIER(regsp, BR | BW);
2126 
2127 	splx(s);
2128 }
2129 
2130 /*
2131  * Initialize UART for use as console or KGDB line.
2132  */
2133 int
2134 cominit(struct com_regs *regsp, int rate, int frequency, int type,
2135     tcflag_t cflag)
2136 {
2137 
2138 	if (bus_space_map(regsp->cr_iot, regsp->cr_iobase, regsp->cr_nports, 0,
2139 		&regsp->cr_ioh))
2140 		return (ENOMEM); /* ??? */
2141 
2142 	if (type == COM_TYPE_OMAP) {
2143 		/* disable before changing settings */
2144 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
2145 	}
2146 
2147 	rate = comspeed(rate, frequency, type);
2148 	if (type != COM_TYPE_AU1x00) {
2149 		/* no EFR on alchemy */
2150 		CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
2151 		CSR_WRITE_1(regsp, COM_REG_EFR, 0);
2152 		CSR_WRITE_1(regsp, COM_REG_LCR, LCR_DLAB);
2153 		CSR_WRITE_1(regsp, COM_REG_DLBL, rate & 0xff);
2154 		CSR_WRITE_1(regsp, COM_REG_DLBH, rate >> 8);
2155 	} else {
2156 		CSR_WRITE_1(regsp, COM_REG_DLBL, rate);
2157 	}
2158 	CSR_WRITE_1(regsp, COM_REG_LCR, cflag2lcr(cflag));
2159 	CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2160 	CSR_WRITE_1(regsp, COM_REG_FIFO,
2161 	    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
2162 
2163 	if (type == COM_TYPE_OMAP) {
2164 		/* setup the fifos.  the FCR value is not used as long
2165 		   as SCR[6] and SCR[7] are 0, which they are at reset
2166 		   and we never touch the SCR register */
2167 		uint8_t rx_fifo_trig = 40;
2168 		uint8_t tx_fifo_trig = 60;
2169 		uint8_t rx_start = 8;
2170 		uint8_t rx_halt = 60;
2171 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
2172 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
2173 
2174 		/* enable access to TCR & TLR */
2175 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS | MCR_TCR_TLR);
2176 
2177 		/* write tcr and tlr values */
2178 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
2179 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
2180 
2181 		/* disable access to TCR & TLR */
2182 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2183 
2184 		/* enable again, but mode is based on speed */
2185 		if (rate > 230400) {
2186 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
2187 		} else {
2188 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
2189 		}
2190 	}
2191 
2192 #ifdef COM_PXA2X0
2193 	if (type == COM_TYPE_PXA2x0)
2194 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
2195 	else
2196 #endif
2197 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
2198 
2199 	return (0);
2200 }
2201 
2202 /*
2203  * Following are all routines needed for COM to act as console
2204  */
2205 struct consdev comcons = {
2206 	NULL, NULL, comcngetc, comcnputc, comcnpollc, NULL, NULL, NULL,
2207 	NODEV, CN_NORMAL
2208 };
2209 
2210 
2211 int
2212 comcnattach1(struct com_regs *regsp, int rate, int frequency, int type,
2213     tcflag_t cflag)
2214 {
2215 	int res;
2216 
2217 	comconsregs = *regsp;
2218 
2219 	res = cominit(&comconsregs, rate, frequency, type, cflag);
2220 	if (res)
2221 		return (res);
2222 
2223 	cn_tab = &comcons;
2224 	cn_init_magic(&com_cnm_state);
2225 	cn_set_magic("\047\001"); /* default magic is BREAK */
2226 
2227 	comconsrate = rate;
2228 	comconscflag = cflag;
2229 
2230 	return (0);
2231 }
2232 
2233 int
2234 comcnattach(bus_space_tag_t iot, bus_addr_t iobase, int rate, int frequency,
2235     int type, tcflag_t cflag)
2236 {
2237 	struct com_regs	regs;
2238 
2239 	memset(&regs, 0, sizeof regs);
2240 	regs.cr_iot = iot;
2241 	regs.cr_iobase = iobase;
2242 	regs.cr_nports = COM_NPORTS;
2243 #ifdef	COM_REGMAP
2244 	memcpy(regs.cr_map, com_std_map, sizeof (regs.cr_map));
2245 #endif
2246 
2247 	return comcnattach1(&regs, rate, frequency, type, cflag);
2248 }
2249 
2250 int
2251 comcngetc(dev_t dev)
2252 {
2253 
2254 	return (com_common_getc(dev, &comconsregs));
2255 }
2256 
2257 /*
2258  * Console kernel output character routine.
2259  */
2260 void
2261 comcnputc(dev_t dev, int c)
2262 {
2263 
2264 	com_common_putc(dev, &comconsregs, c);
2265 }
2266 
2267 void
2268 comcnpollc(dev_t dev, int on)
2269 {
2270 
2271 }
2272 
2273 #ifdef KGDB
2274 int
2275 com_kgdb_attach1(struct com_regs *regsp, int rate, int frequency, int type,
2276     tcflag_t cflag)
2277 {
2278 	int res;
2279 
2280 	if (regsp->cr_iot == comconsregs.cr_iot &&
2281 	    regsp->cr_iobase == comconsregs.cr_iobase) {
2282 #if !defined(DDB)
2283 		return (EBUSY); /* cannot share with console */
2284 #else
2285 		comkgdbregs = *regsp;
2286 		comkgdbregs.cr_ioh = comconsregs.cr_ioh;
2287 #endif
2288 	} else {
2289 		comkgdbregs = *regsp;
2290 		res = cominit(&comkgdbregs, rate, frequency, type, cflag);
2291 		if (res)
2292 			return (res);
2293 
2294 		/*
2295 		 * XXXfvdl this shouldn't be needed, but the cn_magic goo
2296 		 * expects this to be initialized
2297 		 */
2298 		cn_init_magic(&com_cnm_state);
2299 		cn_set_magic("\047\001");
2300 	}
2301 
2302 	kgdb_attach(com_kgdb_getc, com_kgdb_putc, NULL);
2303 	kgdb_dev = 123; /* unneeded, only to satisfy some tests */
2304 
2305 	return (0);
2306 }
2307 
2308 int
2309 com_kgdb_attach(bus_space_tag_t iot, bus_addr_t iobase, int rate,
2310     int frequency, int type, tcflag_t cflag)
2311 {
2312 	struct com_regs regs;
2313 
2314 	regs.cr_iot = iot;
2315 	regs.cr_nports = COM_NPORTS;
2316 	regs.cr_iobase = iobase;
2317 #ifdef COM_REGMAP
2318 	memcpy(regs.cr_map, com_std_map, sizeof (regs.cr_map));
2319 #endif
2320 
2321 	return com_kgdb_attach1(&regs, rate, frequency, type, cflag);
2322 }
2323 
2324 /* ARGSUSED */
2325 int
2326 com_kgdb_getc(void *arg)
2327 {
2328 
2329 	return (com_common_getc(NODEV, &comkgdbregs));
2330 }
2331 
2332 /* ARGSUSED */
2333 void
2334 com_kgdb_putc(void *arg, int c)
2335 {
2336 
2337 	com_common_putc(NODEV, &comkgdbregs, c);
2338 }
2339 #endif /* KGDB */
2340 
2341 /* helper function to identify the com ports used by
2342  console or KGDB (and not yet autoconf attached) */
2343 int
2344 com_is_console(bus_space_tag_t iot, bus_addr_t iobase, bus_space_handle_t *ioh)
2345 {
2346 	bus_space_handle_t help;
2347 
2348 	if (!comconsattached &&
2349 	    iot == comconsregs.cr_iot && iobase == comconsregs.cr_iobase)
2350 		help = comconsregs.cr_ioh;
2351 #ifdef KGDB
2352 	else if (!com_kgdb_attached &&
2353 	    iot == comkgdbregs.cr_iot && iobase == comkgdbregs.cr_iobase)
2354 		help = comkgdbregs.cr_ioh;
2355 #endif
2356 	else
2357 		return (0);
2358 
2359 	if (ioh)
2360 		*ioh = help;
2361 	return (1);
2362 }
2363 
2364 /*
2365  * this routine exists to serve as a shutdown hook for systems that
2366  * have firmware which doesn't interact properly with a com device in
2367  * FIFO mode.
2368  */
2369 bool
2370 com_cleanup(device_t self, int how)
2371 {
2372 	struct com_softc *sc = device_private(self);
2373 
2374 	if (ISSET(sc->sc_hwflags, COM_HW_FIFO))
2375 		CSR_WRITE_1(&sc->sc_regs, COM_REG_FIFO, 0);
2376 
2377 	return true;
2378 }
2379 
2380 bool
2381 com_suspend(device_t self PMF_FN_ARGS)
2382 {
2383 	struct com_softc *sc = device_private(self);
2384 
2385 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, 0);
2386 	(void)CSR_READ_1(&sc->sc_regs, COM_REG_IIR);
2387 
2388 	return true;
2389 }
2390 
2391 bool
2392 com_resume(device_t self PMF_FN_ARGS)
2393 {
2394 	struct com_softc *sc = device_private(self);
2395 
2396 	mutex_spin_enter(&sc->sc_lock);
2397 	com_loadchannelregs(sc);
2398 	mutex_spin_exit(&sc->sc_lock);
2399 
2400 	return true;
2401 }
2402