xref: /netbsd-src/sys/dev/ic/com.c (revision 82d56013d7b633d116a93943de88e08335357a7c)
1 /* $NetBSD: com.c,v 1.363 2021/03/25 05:34:49 rin 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, "$NetBSD: com.c,v 1.363 2021/03/25 05:34:49 rin 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 /* The COM16650 option was renamed to COM_16650. */
79 #ifdef COM16650
80 #error Obsolete COM16650 option; use COM_16650 instead.
81 #endif
82 
83 /*
84  * Override cnmagic(9) macro before including <sys/systm.h>.
85  * We need to know if cn_check_magic triggered debugger, so set a flag.
86  * Callers of cn_check_magic must declare int cn_trapped = 0;
87  * XXX: this is *ugly*!
88  */
89 #define cn_trap()				\
90 	do {					\
91 		console_debugger();		\
92 		cn_trapped = 1;			\
93 		(void)cn_trapped;		\
94 	} while (/* CONSTCOND */ 0)
95 
96 #include <sys/param.h>
97 #include <sys/systm.h>
98 #include <sys/ioctl.h>
99 #include <sys/select.h>
100 #include <sys/poll.h>
101 #include <sys/tty.h>
102 #include <sys/proc.h>
103 #include <sys/conf.h>
104 #include <sys/file.h>
105 #include <sys/uio.h>
106 #include <sys/kernel.h>
107 #include <sys/syslog.h>
108 #include <sys/device.h>
109 #include <sys/malloc.h>
110 #include <sys/timepps.h>
111 #include <sys/vnode.h>
112 #include <sys/kauth.h>
113 #include <sys/intr.h>
114 #ifdef RND_COM
115 #include <sys/rndsource.h>
116 #endif
117 
118 
119 #include <sys/bus.h>
120 
121 #include <dev/ic/comreg.h>
122 #include <dev/ic/comvar.h>
123 #include <dev/ic/ns16550reg.h>
124 #include <dev/ic/st16650reg.h>
125 #include <dev/ic/hayespreg.h>
126 #define	com_lcr	com_cfcr
127 #include <dev/cons.h>
128 
129 #include "ioconf.h"
130 
131 #define	CSR_WRITE_1(r, o, v)	\
132 	bus_space_write_1((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o], v)
133 #define	CSR_READ_1(r, o)	\
134 	bus_space_read_1((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o])
135 #define	CSR_WRITE_2(r, o, v)	\
136 	bus_space_write_2((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o], v)
137 #define	CSR_READ_2(r, o)	\
138 	bus_space_read_2((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o])
139 #define	CSR_WRITE_MULTI(r, o, p, n)	\
140 	bus_space_write_multi_1((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o], p, n)
141 
142 
143 static void com_enable_debugport(struct com_softc *);
144 
145 void	com_config(struct com_softc *);
146 void	com_shutdown(struct com_softc *);
147 int	comspeed(long, long, int);
148 static	u_char	cflag2lcr(tcflag_t);
149 int	comparam(struct tty *, struct termios *);
150 void	comstart(struct tty *);
151 int	comhwiflow(struct tty *, int);
152 
153 void	com_loadchannelregs(struct com_softc *);
154 void	com_hwiflow(struct com_softc *);
155 void	com_break(struct com_softc *, int);
156 void	com_modem(struct com_softc *, int);
157 void	tiocm_to_com(struct com_softc *, u_long, int);
158 int	com_to_tiocm(struct com_softc *);
159 void	com_iflush(struct com_softc *);
160 
161 int	com_common_getc(dev_t, struct com_regs *);
162 static void	com_common_putc(dev_t, struct com_regs *, int, int);
163 
164 int	cominit(struct com_regs *, int, int, int, tcflag_t);
165 
166 static int comcnreattach(void);
167 
168 int	comcngetc(dev_t);
169 void	comcnputc(dev_t, int);
170 void	comcnpollc(dev_t, int);
171 
172 #define	integrate	static inline
173 void	comsoft(void *);
174 integrate void com_rxsoft(struct com_softc *, struct tty *);
175 integrate void com_txsoft(struct com_softc *, struct tty *);
176 integrate void com_stsoft(struct com_softc *, struct tty *);
177 integrate void com_schedrx(struct com_softc *);
178 void	comdiag(void *);
179 
180 dev_type_open(comopen);
181 dev_type_close(comclose);
182 dev_type_read(comread);
183 dev_type_write(comwrite);
184 dev_type_ioctl(comioctl);
185 dev_type_stop(comstop);
186 dev_type_tty(comtty);
187 dev_type_poll(compoll);
188 
189 static struct comcons_info comcons_info;
190 
191 /*
192  * Following are all routines needed for COM to act as console
193  */
194 static struct consdev comcons = {
195 	.cn_getc = comcngetc,
196 	.cn_putc = comcnputc,
197 	.cn_pollc = comcnpollc,
198 	.cn_dev = NODEV,
199 	.cn_pri = CN_NORMAL
200 };
201 
202 
203 const struct cdevsw com_cdevsw = {
204 	.d_open = comopen,
205 	.d_close = comclose,
206 	.d_read = comread,
207 	.d_write = comwrite,
208 	.d_ioctl = comioctl,
209 	.d_stop = comstop,
210 	.d_tty = comtty,
211 	.d_poll = compoll,
212 	.d_mmap = nommap,
213 	.d_kqfilter = ttykqfilter,
214 	.d_discard = nodiscard,
215 	.d_flag = D_TTY
216 };
217 
218 /*
219  * Make this an option variable one can patch.
220  * But be warned:  this must be a power of 2!
221  */
222 u_int com_rbuf_size = COM_RING_SIZE;
223 
224 /* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
225 u_int com_rbuf_hiwat = (COM_RING_SIZE * 1) / 4;
226 u_int com_rbuf_lowat = (COM_RING_SIZE * 3) / 4;
227 
228 static int comconsattached;
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 /* initializer for typical 16550-ish hardware */
242 static const bus_size_t com_std_map[COM_REGMAP_NENTRIES] = {
243 	[COM_REG_RXDATA]	=	com_data,
244 	[COM_REG_TXDATA]	=	com_data,
245 	[COM_REG_DLBL]		=	com_dlbl,
246 	[COM_REG_DLBH]		=	com_dlbh,
247 	[COM_REG_IER]		=	com_ier,
248 	[COM_REG_IIR]		=	com_iir,
249 	[COM_REG_FIFO]		=	com_fifo,
250 	[COM_REG_TCR]		=	com_fifo,
251 	[COM_REG_EFR]		=	com_efr,
252 	[COM_REG_TLR]		=	com_efr,
253 	[COM_REG_LCR]		=	com_lcr,
254 	[COM_REG_MCR]		=	com_mcr,
255 	[COM_REG_LSR]		=	com_lsr,
256 	[COM_REG_MSR]		=	com_msr,
257 	[COM_REG_USR]		=	com_usr,
258 	[COM_REG_TFL]		=	com_tfl,
259 	[COM_REG_RFL]		=	com_rfl,
260 	[COM_REG_HALT]		=	com_halt,
261 	[COM_REG_MDR1]		=	com_mdr1,
262 };
263 
264 #define	COMDIALOUT_MASK	TTDIALOUT_MASK
265 
266 #define	COMUNIT(x)	TTUNIT(x)
267 #define	COMDIALOUT(x)	TTDIALOUT(x)
268 
269 #define	COM_ISALIVE(sc)	((sc)->enabled != 0 && \
270 			 device_is_active((sc)->sc_dev))
271 
272 #define	BR	BUS_SPACE_BARRIER_READ
273 #define	BW	BUS_SPACE_BARRIER_WRITE
274 #define COM_BARRIER(r, f) \
275 	bus_space_barrier((r)->cr_iot, (r)->cr_ioh, 0, (r)->cr_nports, (f))
276 
277 /*
278  * com_init_regs --
279  *	Driver front-ends use this to initialize our register map
280  *	in the standard fashion.  They may then tailor the map to
281  *	their own particular requirements.
282  */
283 void
284 com_init_regs(struct com_regs *regs, bus_space_tag_t st, bus_space_handle_t sh,
285 	      bus_addr_t addr)
286 {
287 
288 	memset(regs, 0, sizeof(*regs));
289 	regs->cr_iot = st;
290 	regs->cr_ioh = sh;
291 	regs->cr_iobase = addr;
292 	regs->cr_nports = COM_NPORTS;
293 	memcpy(regs->cr_map, com_std_map, sizeof(regs->cr_map));
294 }
295 
296 /*
297  * com_init_regs_stride --
298  *	Convenience function for front-ends that have a stride between
299  *	registers.
300  */
301 void
302 com_init_regs_stride(struct com_regs *regs, bus_space_tag_t st,
303 		     bus_space_handle_t sh, bus_addr_t addr, u_int regshift)
304 {
305 
306 	com_init_regs(regs, st, sh, addr);
307 	for (size_t i = 0; i < __arraycount(regs->cr_map); i++) {
308 		regs->cr_map[i] <<= regshift;
309 	}
310 	regs->cr_nports <<= regshift;
311 }
312 
313 /*ARGSUSED*/
314 int
315 comspeed(long speed, long frequency, int type)
316 {
317 #define	divrnd(n, q)	(((n)*2/(q)+1)/2)	/* divide and round off */
318 
319 	int x, err;
320 	int divisor = 16;
321 
322 	if ((type == COM_TYPE_OMAP) && (speed > 230400)) {
323 	    divisor = 13;
324 	}
325 
326 	if (speed == 0)
327 		return (0);
328 	if (speed < 0)
329 		return (-1);
330 	x = divrnd(frequency / divisor, speed);
331 	if (x <= 0)
332 		return (-1);
333 	err = divrnd(((quad_t)frequency) * 1000 / divisor, speed * x) - 1000;
334 	if (err < 0)
335 		err = -err;
336 	if (err > COM_TOLERANCE)
337 		return (-1);
338 	return (x);
339 
340 #undef	divrnd
341 }
342 
343 #ifdef COM_DEBUG
344 int	com_debug = 0;
345 
346 void comstatus(struct com_softc *, const char *);
347 void
348 comstatus(struct com_softc *sc, const char *str)
349 {
350 	struct tty *tp = sc->sc_tty;
351 
352 	aprint_normal_dev(sc->sc_dev,
353 	    "%s %cclocal  %cdcd %cts_carr_on %cdtr %ctx_stopped\n",
354 	    str,
355 	    ISSET(tp->t_cflag, CLOCAL) ? '+' : '-',
356 	    ISSET(sc->sc_msr, MSR_DCD) ? '+' : '-',
357 	    ISSET(tp->t_state, TS_CARR_ON) ? '+' : '-',
358 	    ISSET(sc->sc_mcr, MCR_DTR) ? '+' : '-',
359 	    sc->sc_tx_stopped ? '+' : '-');
360 
361 	aprint_normal_dev(sc->sc_dev,
362 	    "%s %ccrtscts %ccts %cts_ttstop  %crts rx_flags=0x%x\n",
363 	    str,
364 	    ISSET(tp->t_cflag, CRTSCTS) ? '+' : '-',
365 	    ISSET(sc->sc_msr, MSR_CTS) ? '+' : '-',
366 	    ISSET(tp->t_state, TS_TTSTOP) ? '+' : '-',
367 	    ISSET(sc->sc_mcr, MCR_RTS) ? '+' : '-',
368 	    sc->sc_rx_flags);
369 }
370 #endif
371 
372 int
373 com_probe_subr(struct com_regs *regs)
374 {
375 
376 	/* force access to id reg */
377 	CSR_WRITE_1(regs, COM_REG_LCR, LCR_8BITS);
378 	CSR_WRITE_1(regs, COM_REG_IIR, 0);
379 	if ((CSR_READ_1(regs, COM_REG_LCR) != LCR_8BITS) ||
380 	    (CSR_READ_1(regs, COM_REG_IIR) & 0x38))
381 		return (0);
382 
383 	return (1);
384 }
385 
386 int
387 comprobe1(bus_space_tag_t iot, bus_space_handle_t ioh)
388 {
389 	struct com_regs	regs;
390 
391 	com_init_regs(&regs, iot, ioh, 0/*XXX*/);
392 
393 	return com_probe_subr(&regs);
394 }
395 
396 /*
397  * No locking in this routine; it is only called during attach,
398  * or with the port already locked.
399  */
400 static void
401 com_enable_debugport(struct com_softc *sc)
402 {
403 
404 	/* Turn on line break interrupt, set carrier. */
405 	sc->sc_ier = IER_ERLS;
406 	if (sc->sc_type == COM_TYPE_PXA2x0)
407 		sc->sc_ier |= IER_EUART | IER_ERXTOUT;
408 	if (sc->sc_type == COM_TYPE_INGENIC ||
409 	    sc->sc_type == COM_TYPE_TEGRA)
410 		sc->sc_ier |= IER_ERXTOUT;
411 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
412 	SET(sc->sc_mcr, MCR_DTR | MCR_RTS);
413 	CSR_WRITE_1(&sc->sc_regs, COM_REG_MCR, sc->sc_mcr);
414 }
415 
416 static void
417 com_intr_poll(void *arg)
418 {
419 	struct com_softc * const sc = arg;
420 
421 	comintr(sc);
422 
423 	callout_schedule(&sc->sc_poll_callout, sc->sc_poll_ticks);
424 }
425 
426 void
427 com_attach_subr(struct com_softc *sc)
428 {
429 	struct com_regs *regsp = &sc->sc_regs;
430 	struct tty *tp;
431 	uint32_t cpr;
432 	uint8_t lcr;
433 	const char *fifo_msg = NULL;
434 	prop_dictionary_t dict;
435 	bool is_console = true;
436 	bool force_console = false;
437 
438 	aprint_naive("\n");
439 
440 	dict = device_properties(sc->sc_dev);
441 	prop_dictionary_get_bool(dict, "is_console", &is_console);
442 	prop_dictionary_get_bool(dict, "force_console", &force_console);
443 	callout_init(&sc->sc_diag_callout, 0);
444 	callout_init(&sc->sc_poll_callout, 0);
445 	callout_setfunc(&sc->sc_poll_callout, com_intr_poll, sc);
446 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_HIGH);
447 
448 #if defined(COM_16650)
449 	sc->sc_type = COM_TYPE_16650;
450 #elif defined(COM_16750)
451 	sc->sc_type = COM_TYPE_16750;
452 #elif defined(COM_HAYESP)
453 	sc->sc_type = COM_TYPE_HAYESP;
454 #elif defined(COM_PXA2X0)
455 	sc->sc_type = COM_TYPE_PXA2x0;
456 #endif
457 
458 	/* Disable interrupts before configuring the device. */
459 	if (sc->sc_type == COM_TYPE_PXA2x0)
460 		sc->sc_ier = IER_EUART;
461 	else
462 		sc->sc_ier = 0;
463 
464 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
465 
466 	if ((bus_space_is_equal(regsp->cr_iot, comcons_info.regs.cr_iot) &&
467 	    regsp->cr_iobase == comcons_info.regs.cr_iobase) || force_console) {
468 		comconsattached = 1;
469 
470 		if (force_console)
471 			memcpy(regsp, &comcons_info.regs, sizeof(*regsp));
472 
473 		if (cn_tab == NULL && comcnreattach() != 0) {
474 			printf("can't re-init serial console @%lx\n",
475 			    (u_long)comcons_info.regs.cr_iobase);
476 		}
477 
478 		switch (sc->sc_type) {
479 		case COM_TYPE_16750:
480 		case COM_TYPE_DW_APB:
481 			/* Use in comintr(). */
482  			sc->sc_lcr = cflag2lcr(comcons_info.cflag);
483 			break;
484 		}
485 
486 		/* Make sure the console is always "hardwired". */
487 		delay(10000);			/* wait for output to finish */
488 		if (is_console) {
489 			SET(sc->sc_hwflags, COM_HW_CONSOLE);
490 		}
491 
492 		SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
493 	}
494 
495 	/* Probe for FIFO */
496 	switch (sc->sc_type) {
497 	case COM_TYPE_HAYESP:
498 		goto fifodone;
499 
500 	case COM_TYPE_AU1x00:
501 		sc->sc_fifolen = 16;
502 		fifo_msg = "Au1X00 UART";
503 		SET(sc->sc_hwflags, COM_HW_FIFO);
504 		goto fifodelay;
505 
506 	case COM_TYPE_16550_NOERS:
507 		sc->sc_fifolen = 16;
508 		fifo_msg = "ns16650, no ERS";
509 		SET(sc->sc_hwflags, COM_HW_FIFO);
510 		goto fifodelay;
511 
512 	case COM_TYPE_OMAP:
513 		sc->sc_fifolen = 64;
514 		fifo_msg = "OMAP UART";
515 		SET(sc->sc_hwflags, COM_HW_FIFO);
516 		goto fifodelay;
517 
518 	case COM_TYPE_INGENIC:
519 		sc->sc_fifolen = 16;
520 		fifo_msg = "Ingenic UART";
521 		SET(sc->sc_hwflags, COM_HW_FIFO);
522 		SET(sc->sc_hwflags, COM_HW_NOIEN);
523 		goto fifodelay;
524 
525 	case COM_TYPE_TEGRA:
526 		sc->sc_fifolen = 8;
527 		fifo_msg = "Tegra UART";
528 		SET(sc->sc_hwflags, COM_HW_FIFO);
529 		CSR_WRITE_1(regsp, COM_REG_FIFO,
530 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
531 		goto fifodelay;
532 
533 	case COM_TYPE_BCMAUXUART:
534 		sc->sc_fifolen = 1;
535 		fifo_msg = "BCM AUX UART";
536 		SET(sc->sc_hwflags, COM_HW_FIFO);
537 		CSR_WRITE_1(regsp, COM_REG_FIFO,
538 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
539 		goto fifodelay;
540 
541 	case COM_TYPE_DW_APB:
542 		cpr = bus_space_read_4(sc->sc_regs.cr_iot, sc->sc_regs.cr_ioh,
543 		    DW_APB_UART_CPR);
544 		sc->sc_fifolen = __SHIFTOUT(cpr, UART_CPR_FIFO_MODE) * 16;
545 		if (sc->sc_fifolen == 0) {
546 			sc->sc_fifolen = 1;
547 			fifo_msg = "DesignWare APB UART, no fifo";
548 			CSR_WRITE_1(regsp, COM_REG_FIFO, 0);
549 		} else {
550 			fifo_msg = "DesignWare APB UART";
551 			SET(sc->sc_hwflags, COM_HW_FIFO);
552 			CSR_WRITE_1(regsp, COM_REG_FIFO,
553 			    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
554 		}
555 		goto fifodelay;
556 	}
557 
558 	sc->sc_fifolen = 1;
559 	/* look for a NS 16550AF UART with FIFOs */
560 	if (sc->sc_type == COM_TYPE_INGENIC) {
561 		CSR_WRITE_1(regsp, COM_REG_FIFO,
562 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
563 		    FIFO_TRIGGER_14 | FIFO_UART_ON);
564 	} else
565 		CSR_WRITE_1(regsp, COM_REG_FIFO,
566 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_14);
567 	delay(100);
568 	if (ISSET(CSR_READ_1(regsp, COM_REG_IIR), IIR_FIFO_MASK)
569 	    == IIR_FIFO_MASK)
570 		if (ISSET(CSR_READ_1(regsp, COM_REG_FIFO), FIFO_TRIGGER_14)
571 		    == FIFO_TRIGGER_14) {
572 			SET(sc->sc_hwflags, COM_HW_FIFO);
573 
574 			fifo_msg = "ns16550a";
575 
576 			/*
577 			 * IIR changes into the EFR if LCR is set to LCR_EERS
578 			 * on 16650s. We also know IIR != 0 at this point.
579 			 * Write 0 into the EFR, and read it. If the result
580 			 * is 0, we have a 16650.
581 			 *
582 			 * Older 16650s were broken; the test to detect them
583 			 * is taken from the Linux driver. Apparently
584 			 * setting DLAB enable gives access to the EFR on
585 			 * these chips.
586 			 */
587 			if (sc->sc_type == COM_TYPE_16650) {
588 				lcr = CSR_READ_1(regsp, COM_REG_LCR);
589 				CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
590 				CSR_WRITE_1(regsp, COM_REG_EFR, 0);
591 				if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
592 					CSR_WRITE_1(regsp, COM_REG_LCR,
593 					    lcr | LCR_DLAB);
594 					if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
595 						CLR(sc->sc_hwflags, COM_HW_FIFO);
596 						sc->sc_fifolen = 0;
597 					} else {
598 						SET(sc->sc_hwflags, COM_HW_FLOW);
599 						sc->sc_fifolen = 32;
600 					}
601 				} else
602 					sc->sc_fifolen = 16;
603 
604 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
605 				if (sc->sc_fifolen == 0)
606 					fifo_msg = "st16650, broken fifo";
607 				else if (sc->sc_fifolen == 32)
608 					fifo_msg = "st16650a";
609 				else
610 					fifo_msg = "ns16550a";
611 			}
612 
613 			/*
614 			 * TL16C750 can enable 64byte FIFO, only when DLAB
615 			 * is 1.  However, some 16750 may always enable.  For
616 			 * example, restrictions according to DLAB in a data
617 			 * sheet for SC16C750 were not described.
618 			 * Please enable 'options COM_16650', supposing you
619 			 * use SC16C750.  Probably 32 bytes of FIFO and HW FLOW
620 			 * should become effective.
621 			 */
622 			if (sc->sc_type == COM_TYPE_16750) {
623 				uint8_t iir1, iir2;
624 				uint8_t fcr = FIFO_ENABLE | FIFO_TRIGGER_14;
625 
626 				lcr = CSR_READ_1(regsp, COM_REG_LCR);
627 				CSR_WRITE_1(regsp, COM_REG_LCR,
628 				    lcr & ~LCR_DLAB);
629 				CSR_WRITE_1(regsp, COM_REG_FIFO,
630 				    fcr | FIFO_64B_ENABLE);
631 				iir1 = CSR_READ_1(regsp, COM_REG_IIR);
632 				CSR_WRITE_1(regsp, COM_REG_FIFO, fcr);
633 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr | LCR_DLAB);
634 				CSR_WRITE_1(regsp, COM_REG_FIFO,
635 				    fcr | FIFO_64B_ENABLE);
636 				iir2 = CSR_READ_1(regsp, COM_REG_IIR);
637 
638 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
639 
640 				if (!ISSET(iir1, IIR_64B_FIFO) &&
641 				    ISSET(iir2, IIR_64B_FIFO)) {
642 					/* It is TL16C750. */
643 					sc->sc_fifolen = 64;
644 					SET(sc->sc_hwflags, COM_HW_AFE);
645 				} else
646 					CSR_WRITE_1(regsp, COM_REG_FIFO, fcr);
647 
648 				if (sc->sc_fifolen == 64)
649 					fifo_msg = "tl16c750";
650 				else
651 					fifo_msg = "ns16750";
652 			}
653 		} else
654 			fifo_msg = "ns16550, broken fifo";
655 	else
656 		fifo_msg = "ns8250 or ns16450, no fifo";
657 	CSR_WRITE_1(regsp, COM_REG_FIFO, 0);
658 
659 fifodelay:
660 	/*
661 	 * Some chips will clear down both Tx and Rx FIFOs when zero is
662 	 * written to com_fifo. If this chip is the console, writing zero
663 	 * results in some of the chip/FIFO description being lost, so delay
664 	 * printing it until now.
665 	 */
666 	delay(10);
667 	if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
668 		aprint_normal(": %s, %d-byte FIFO\n", fifo_msg, sc->sc_fifolen);
669 	} else {
670 		aprint_normal(": %s\n", fifo_msg);
671 	}
672 	if (ISSET(sc->sc_hwflags, COM_HW_TXFIFO_DISABLE)) {
673 		sc->sc_fifolen = 1;
674 		aprint_normal_dev(sc->sc_dev, "txfifo disabled\n");
675 	}
676 
677 fifodone:
678 
679 	tp = tty_alloc();
680 	tp->t_oproc = comstart;
681 	tp->t_param = comparam;
682 	tp->t_hwiflow = comhwiflow;
683 	tp->t_softc = sc;
684 
685 	sc->sc_tty = tp;
686 	sc->sc_rbuf = malloc(com_rbuf_size << 1, M_DEVBUF, M_WAITOK);
687 	sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
688 	sc->sc_rbavail = com_rbuf_size;
689 	sc->sc_ebuf = sc->sc_rbuf + (com_rbuf_size << 1);
690 
691 	tty_attach(tp);
692 
693 	if (!ISSET(sc->sc_hwflags, COM_HW_NOIEN))
694 		SET(sc->sc_mcr, MCR_IENABLE);
695 
696 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
697 		int maj;
698 
699 		/* locate the major number */
700 		maj = cdevsw_lookup_major(&com_cdevsw);
701 
702 		tp->t_dev = cn_tab->cn_dev = makedev(maj,
703 						     device_unit(sc->sc_dev));
704 
705 		aprint_normal_dev(sc->sc_dev, "console\n");
706 	}
707 
708 #ifdef KGDB
709 	/*
710 	 * Allow kgdb to "take over" this port.  If this is
711 	 * not the console and is the kgdb device, it has
712 	 * exclusive use.  If it's the console _and_ the
713 	 * kgdb device, it doesn't.
714 	 */
715 	if (bus_space_is_equal(regsp->cr_iot, comkgdbregs.cr_iot) &&
716 	    regsp->cr_iobase == comkgdbregs.cr_iobase) {
717 		if (!ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
718 			com_kgdb_attached = 1;
719 
720 			SET(sc->sc_hwflags, COM_HW_KGDB);
721 		}
722 		aprint_normal_dev(sc->sc_dev, "kgdb\n");
723 	}
724 #endif
725 
726 	sc->sc_si = softint_establish(SOFTINT_SERIAL, comsoft, sc);
727 
728 #ifdef RND_COM
729 	rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
730 			  RND_TYPE_TTY, RND_FLAG_DEFAULT);
731 #endif
732 
733 	/* if there are no enable/disable functions, assume the device
734 	   is always enabled */
735 	if (!sc->enable)
736 		sc->enabled = 1;
737 
738 	com_config(sc);
739 
740 	SET(sc->sc_hwflags, COM_HW_DEV_OK);
741 
742 	if (sc->sc_poll_ticks != 0)
743 		callout_schedule(&sc->sc_poll_callout, sc->sc_poll_ticks);
744 }
745 
746 void
747 com_config(struct com_softc *sc)
748 {
749 	struct com_regs *regsp = &sc->sc_regs;
750 
751 	/* Disable interrupts before configuring the device. */
752 	if (sc->sc_type == COM_TYPE_PXA2x0)
753 		sc->sc_ier = IER_EUART;
754 	else
755 		sc->sc_ier = 0;
756 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
757 	(void) CSR_READ_1(regsp, COM_REG_IIR);
758 
759 	/* Look for a Hayes ESP board. */
760 	if (sc->sc_type == COM_TYPE_HAYESP) {
761 
762 		/* Set 16550 compatibility mode */
763 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
764 				  HAYESP_SETMODE);
765 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
766 				  HAYESP_MODE_FIFO|HAYESP_MODE_RTS|
767 				  HAYESP_MODE_SCALE);
768 
769 		/* Set RTS/CTS flow control */
770 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
771 				  HAYESP_SETFLOWTYPE);
772 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
773 				  HAYESP_FLOW_RTS);
774 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
775 				  HAYESP_FLOW_CTS);
776 
777 		/* Set flow control levels */
778 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
779 				  HAYESP_SETRXFLOW);
780 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
781 				  HAYESP_HIBYTE(HAYESP_RXHIWMARK));
782 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
783 				  HAYESP_LOBYTE(HAYESP_RXHIWMARK));
784 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
785 				  HAYESP_HIBYTE(HAYESP_RXLOWMARK));
786 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
787 				  HAYESP_LOBYTE(HAYESP_RXLOWMARK));
788 	}
789 
790 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE|COM_HW_KGDB))
791 		com_enable_debugport(sc);
792 }
793 
794 #if 0
795 static int
796 comcngetc_detached(dev_t dev)
797 {
798 	return 0;
799 }
800 
801 static void
802 comcnputc_detached(dev_t dev, int c)
803 {
804 }
805 #endif
806 
807 int
808 com_detach(device_t self, int flags)
809 {
810 	struct com_softc *sc = device_private(self);
811 	int maj, mn;
812 
813 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
814 		return EBUSY;
815 
816 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE) &&
817 	    (flags & DETACH_SHUTDOWN) != 0)
818 		return EBUSY;
819 
820 	if (sc->disable != NULL && sc->enabled != 0) {
821 		(*sc->disable)(sc);
822 		sc->enabled = 0;
823 	}
824 
825 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
826 		comconsattached = 0;
827 		cn_tab = NULL;
828 	}
829 
830 	/* locate the major number */
831 	maj = cdevsw_lookup_major(&com_cdevsw);
832 
833 	/* Nuke the vnodes for any open instances. */
834 	mn = device_unit(self);
835 	vdevgone(maj, mn, mn, VCHR);
836 
837 	mn |= COMDIALOUT_MASK;
838 	vdevgone(maj, mn, mn, VCHR);
839 
840 	if (sc->sc_rbuf == NULL) {
841 		/*
842 		 * Ring buffer allocation failed in the com_attach_subr,
843 		 * only the tty is allocated, and nothing else.
844 		 */
845 		tty_free(sc->sc_tty);
846 		return 0;
847 	}
848 
849 	/* Free the receive buffer. */
850 	free(sc->sc_rbuf, M_DEVBUF);
851 
852 	/* Detach and free the tty. */
853 	tty_detach(sc->sc_tty);
854 	tty_free(sc->sc_tty);
855 
856 	/* Unhook the soft interrupt handler. */
857 	softint_disestablish(sc->sc_si);
858 
859 #ifdef RND_COM
860 	/* Unhook the entropy source. */
861 	rnd_detach_source(&sc->rnd_source);
862 #endif
863 	callout_destroy(&sc->sc_diag_callout);
864 
865 	/* Destroy the lock. */
866 	mutex_destroy(&sc->sc_lock);
867 
868 	return (0);
869 }
870 
871 void
872 com_shutdown(struct com_softc *sc)
873 {
874 	struct tty *tp = sc->sc_tty;
875 
876 	mutex_spin_enter(&sc->sc_lock);
877 
878 	/* If we were asserting flow control, then deassert it. */
879 	SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
880 	com_hwiflow(sc);
881 
882 	/* Clear any break condition set with TIOCSBRK. */
883 	com_break(sc, 0);
884 
885 	/*
886 	 * Hang up if necessary.  Wait a bit, so the other side has time to
887 	 * notice even if we immediately open the port again.
888 	 * Avoid tsleeping above splhigh().
889 	 */
890 	if (ISSET(tp->t_cflag, HUPCL)) {
891 		com_modem(sc, 0);
892 		mutex_spin_exit(&sc->sc_lock);
893 		/* XXX will only timeout */
894 		(void) kpause(ttclos, false, hz, NULL);
895 		mutex_spin_enter(&sc->sc_lock);
896 	}
897 
898 	/* Turn off interrupts. */
899 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
900 		sc->sc_ier = IER_ERLS; /* interrupt on line break */
901 		if ((sc->sc_type == COM_TYPE_PXA2x0) ||
902 		    (sc->sc_type == COM_TYPE_INGENIC) ||
903 		    (sc->sc_type == COM_TYPE_TEGRA))
904 			sc->sc_ier |= IER_ERXTOUT;
905 	} else
906 		sc->sc_ier = 0;
907 
908 	if (sc->sc_type == COM_TYPE_PXA2x0)
909 		sc->sc_ier |= IER_EUART;
910 
911 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
912 
913 	mutex_spin_exit(&sc->sc_lock);
914 
915 	if (sc->disable) {
916 #ifdef DIAGNOSTIC
917 		if (!sc->enabled)
918 			panic("com_shutdown: not enabled?");
919 #endif
920 		(*sc->disable)(sc);
921 		sc->enabled = 0;
922 	}
923 }
924 
925 int
926 comopen(dev_t dev, int flag, int mode, struct lwp *l)
927 {
928 	struct com_softc *sc;
929 	struct tty *tp;
930 	int s;
931 	int error;
932 
933 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
934 	if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK) ||
935 		sc->sc_rbuf == NULL)
936 		return (ENXIO);
937 
938 	if (!device_is_active(sc->sc_dev))
939 		return (ENXIO);
940 
941 #ifdef KGDB
942 	/*
943 	 * If this is the kgdb port, no other use is permitted.
944 	 */
945 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
946 		return (EBUSY);
947 #endif
948 
949 	tp = sc->sc_tty;
950 
951 	/*
952 	 * If the device is exclusively for kernel use, deny userland
953 	 * open.
954 	 */
955 	if (ISSET(tp->t_state, TS_KERN_ONLY))
956 		return (EBUSY);
957 
958 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
959 		return (EBUSY);
960 
961 	s = spltty();
962 
963 	/*
964 	 * Do the following iff this is a first open.
965 	 */
966 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
967 		struct termios t;
968 
969 		tp->t_dev = dev;
970 
971 		if (sc->enable) {
972 			if ((*sc->enable)(sc)) {
973 				splx(s);
974 				aprint_error_dev(sc->sc_dev,
975 				    "device enable failed\n");
976 				return (EIO);
977 			}
978 			mutex_spin_enter(&sc->sc_lock);
979 			sc->enabled = 1;
980 			com_config(sc);
981 		} else {
982 			mutex_spin_enter(&sc->sc_lock);
983 		}
984 
985 		/* Turn on interrupts. */
986 		sc->sc_ier = IER_ERXRDY | IER_ERLS;
987 		if (!ISSET(tp->t_cflag, CLOCAL))
988 			sc->sc_ier |= IER_EMSC;
989 
990 		if (sc->sc_type == COM_TYPE_PXA2x0)
991 			sc->sc_ier |= IER_EUART | IER_ERXTOUT;
992 		else if (sc->sc_type == COM_TYPE_INGENIC ||
993 			 sc->sc_type == COM_TYPE_TEGRA)
994 			sc->sc_ier |= IER_ERXTOUT;
995 		CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
996 
997 		/* Fetch the current modem control status, needed later. */
998 		sc->sc_msr = CSR_READ_1(&sc->sc_regs, COM_REG_MSR);
999 
1000 		/* Clear PPS capture state on first open. */
1001 		mutex_spin_enter(&timecounter_lock);
1002 		memset(&sc->sc_pps_state, 0, sizeof(sc->sc_pps_state));
1003 		sc->sc_pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
1004 		pps_init(&sc->sc_pps_state);
1005 		mutex_spin_exit(&timecounter_lock);
1006 
1007 		mutex_spin_exit(&sc->sc_lock);
1008 
1009 		/*
1010 		 * Initialize the termios status to the defaults.  Add in the
1011 		 * sticky bits from TIOCSFLAGS.
1012 		 */
1013 		if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
1014 			t.c_ospeed = comcons_info.rate;
1015 			t.c_cflag = comcons_info.cflag;
1016 		} else {
1017 			t.c_ospeed = TTYDEF_SPEED;
1018 			t.c_cflag = TTYDEF_CFLAG;
1019 		}
1020 		t.c_ispeed = t.c_ospeed;
1021 		if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
1022 			SET(t.c_cflag, CLOCAL);
1023 		if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
1024 			SET(t.c_cflag, CRTSCTS);
1025 		if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
1026 			SET(t.c_cflag, MDMBUF);
1027 		/* Make sure comparam() will do something. */
1028 		tp->t_ospeed = 0;
1029 		(void) comparam(tp, &t);
1030 		tp->t_iflag = TTYDEF_IFLAG;
1031 		tp->t_oflag = TTYDEF_OFLAG;
1032 		tp->t_lflag = TTYDEF_LFLAG;
1033 		ttychars(tp);
1034 		ttsetwater(tp);
1035 
1036 		mutex_spin_enter(&sc->sc_lock);
1037 
1038 		/*
1039 		 * Turn on DTR.  We must always do this, even if carrier is not
1040 		 * present, because otherwise we'd have to use TIOCSDTR
1041 		 * immediately after setting CLOCAL, which applications do not
1042 		 * expect.  We always assert DTR while the device is open
1043 		 * unless explicitly requested to deassert it.
1044 		 */
1045 		com_modem(sc, 1);
1046 
1047 		/* Clear the input ring, and unblock. */
1048 		sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
1049 		sc->sc_rbavail = com_rbuf_size;
1050 		com_iflush(sc);
1051 		CLR(sc->sc_rx_flags, RX_ANY_BLOCK);
1052 		com_hwiflow(sc);
1053 
1054 #ifdef COM_DEBUG
1055 		if (com_debug)
1056 			comstatus(sc, "comopen  ");
1057 #endif
1058 
1059 		mutex_spin_exit(&sc->sc_lock);
1060 	}
1061 
1062 	splx(s);
1063 
1064 	error = ttyopen(tp, COMDIALOUT(dev), ISSET(flag, O_NONBLOCK));
1065 	if (error)
1066 		goto bad;
1067 
1068 	error = (*tp->t_linesw->l_open)(dev, tp);
1069 	if (error)
1070 		goto bad;
1071 
1072 	return (0);
1073 
1074 bad:
1075 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
1076 		/*
1077 		 * We failed to open the device, and nobody else had it opened.
1078 		 * Clean up the state as appropriate.
1079 		 */
1080 		com_shutdown(sc);
1081 	}
1082 
1083 	return (error);
1084 }
1085 
1086 int
1087 comclose(dev_t dev, int flag, int mode, struct lwp *l)
1088 {
1089 	struct com_softc *sc =
1090 	    device_lookup_private(&com_cd, COMUNIT(dev));
1091 	struct tty *tp = sc->sc_tty;
1092 
1093 	/* XXX This is for cons.c. */
1094 	if (!ISSET(tp->t_state, TS_ISOPEN))
1095 		return (0);
1096 	/*
1097 	 * If the device is exclusively for kernel use, deny userland
1098 	 * close.
1099 	 */
1100 	if (ISSET(tp->t_state, TS_KERN_ONLY))
1101 		return (0);
1102 
1103 	(*tp->t_linesw->l_close)(tp, flag);
1104 	ttyclose(tp);
1105 
1106 	if (COM_ISALIVE(sc) == 0)
1107 		return (0);
1108 
1109 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
1110 		/*
1111 		 * Although we got a last close, the device may still be in
1112 		 * use; e.g. if this was the dialout node, and there are still
1113 		 * processes waiting for carrier on the non-dialout node.
1114 		 */
1115 		com_shutdown(sc);
1116 	}
1117 
1118 	return (0);
1119 }
1120 
1121 int
1122 comread(dev_t dev, struct uio *uio, int flag)
1123 {
1124 	struct com_softc *sc =
1125 	    device_lookup_private(&com_cd, COMUNIT(dev));
1126 	struct tty *tp = sc->sc_tty;
1127 
1128 	if (COM_ISALIVE(sc) == 0)
1129 		return (EIO);
1130 
1131 	return ((*tp->t_linesw->l_read)(tp, uio, flag));
1132 }
1133 
1134 int
1135 comwrite(dev_t dev, struct uio *uio, int flag)
1136 {
1137 	struct com_softc *sc =
1138 	    device_lookup_private(&com_cd, COMUNIT(dev));
1139 	struct tty *tp = sc->sc_tty;
1140 
1141 	if (COM_ISALIVE(sc) == 0)
1142 		return (EIO);
1143 
1144 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
1145 }
1146 
1147 int
1148 compoll(dev_t dev, int events, struct lwp *l)
1149 {
1150 	struct com_softc *sc =
1151 	    device_lookup_private(&com_cd, COMUNIT(dev));
1152 	struct tty *tp = sc->sc_tty;
1153 
1154 	if (COM_ISALIVE(sc) == 0)
1155 		return (POLLHUP);
1156 
1157 	return ((*tp->t_linesw->l_poll)(tp, events, l));
1158 }
1159 
1160 struct tty *
1161 comtty(dev_t dev)
1162 {
1163 	struct com_softc *sc =
1164 	    device_lookup_private(&com_cd, COMUNIT(dev));
1165 	struct tty *tp = sc->sc_tty;
1166 
1167 	return (tp);
1168 }
1169 
1170 int
1171 comioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
1172 {
1173 	struct com_softc *sc;
1174 	struct tty *tp;
1175 	int error;
1176 
1177 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
1178 	if (sc == NULL)
1179 		return ENXIO;
1180 	if (COM_ISALIVE(sc) == 0)
1181 		return (EIO);
1182 
1183 	tp = sc->sc_tty;
1184 
1185 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
1186 	if (error != EPASSTHROUGH)
1187 		return (error);
1188 
1189 	error = ttioctl(tp, cmd, data, flag, l);
1190 	if (error != EPASSTHROUGH)
1191 		return (error);
1192 
1193 	error = 0;
1194 	switch (cmd) {
1195 	case TIOCSFLAGS:
1196 		error = kauth_authorize_device_tty(l->l_cred,
1197 		    KAUTH_DEVICE_TTY_PRIVSET, tp);
1198 		break;
1199 	default:
1200 		/* nothing */
1201 		break;
1202 	}
1203 	if (error) {
1204 		return error;
1205 	}
1206 
1207 	mutex_spin_enter(&sc->sc_lock);
1208 
1209 	switch (cmd) {
1210 	case TIOCSBRK:
1211 		com_break(sc, 1);
1212 		break;
1213 
1214 	case TIOCCBRK:
1215 		com_break(sc, 0);
1216 		break;
1217 
1218 	case TIOCSDTR:
1219 		com_modem(sc, 1);
1220 		break;
1221 
1222 	case TIOCCDTR:
1223 		com_modem(sc, 0);
1224 		break;
1225 
1226 	case TIOCGFLAGS:
1227 		*(int *)data = sc->sc_swflags;
1228 		break;
1229 
1230 	case TIOCSFLAGS:
1231 		sc->sc_swflags = *(int *)data;
1232 		break;
1233 
1234 	case TIOCMSET:
1235 	case TIOCMBIS:
1236 	case TIOCMBIC:
1237 		tiocm_to_com(sc, cmd, *(int *)data);
1238 		break;
1239 
1240 	case TIOCMGET:
1241 		*(int *)data = com_to_tiocm(sc);
1242 		break;
1243 
1244 	case PPS_IOC_CREATE:
1245 	case PPS_IOC_DESTROY:
1246 	case PPS_IOC_GETPARAMS:
1247 	case PPS_IOC_SETPARAMS:
1248 	case PPS_IOC_GETCAP:
1249 	case PPS_IOC_FETCH:
1250 #ifdef PPS_SYNC
1251 	case PPS_IOC_KCBIND:
1252 #endif
1253 		mutex_spin_enter(&timecounter_lock);
1254 		error = pps_ioctl(cmd, data, &sc->sc_pps_state);
1255 		mutex_spin_exit(&timecounter_lock);
1256 		break;
1257 
1258 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
1259 		mutex_spin_enter(&timecounter_lock);
1260 #ifndef PPS_TRAILING_EDGE
1261 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1262 		    &sc->sc_pps_state.ppsinfo.assert_timestamp);
1263 #else
1264 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1265 		    &sc->sc_pps_state.ppsinfo.clear_timestamp);
1266 #endif
1267 		mutex_spin_exit(&timecounter_lock);
1268 		break;
1269 
1270 	default:
1271 		error = EPASSTHROUGH;
1272 		break;
1273 	}
1274 
1275 	mutex_spin_exit(&sc->sc_lock);
1276 
1277 #ifdef COM_DEBUG
1278 	if (com_debug)
1279 		comstatus(sc, "comioctl ");
1280 #endif
1281 
1282 	return (error);
1283 }
1284 
1285 integrate void
1286 com_schedrx(struct com_softc *sc)
1287 {
1288 
1289 	sc->sc_rx_ready = 1;
1290 
1291 	/* Wake up the poller. */
1292 	softint_schedule(sc->sc_si);
1293 }
1294 
1295 void
1296 com_break(struct com_softc *sc, int onoff)
1297 {
1298 
1299 	if (onoff)
1300 		SET(sc->sc_lcr, LCR_SBREAK);
1301 	else
1302 		CLR(sc->sc_lcr, LCR_SBREAK);
1303 
1304 	if (!sc->sc_heldchange) {
1305 		if (sc->sc_tx_busy) {
1306 			sc->sc_heldtbc = sc->sc_tbc;
1307 			sc->sc_tbc = 0;
1308 			sc->sc_heldchange = 1;
1309 		} else
1310 			com_loadchannelregs(sc);
1311 	}
1312 }
1313 
1314 void
1315 com_modem(struct com_softc *sc, int onoff)
1316 {
1317 
1318 	if (sc->sc_mcr_dtr == 0)
1319 		return;
1320 
1321 	if (onoff)
1322 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1323 	else
1324 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1325 
1326 	if (!sc->sc_heldchange) {
1327 		if (sc->sc_tx_busy) {
1328 			sc->sc_heldtbc = sc->sc_tbc;
1329 			sc->sc_tbc = 0;
1330 			sc->sc_heldchange = 1;
1331 		} else
1332 			com_loadchannelregs(sc);
1333 	}
1334 }
1335 
1336 void
1337 tiocm_to_com(struct com_softc *sc, u_long how, int ttybits)
1338 {
1339 	u_char combits;
1340 
1341 	combits = 0;
1342 	if (ISSET(ttybits, TIOCM_DTR))
1343 		SET(combits, MCR_DTR);
1344 	if (ISSET(ttybits, TIOCM_RTS))
1345 		SET(combits, MCR_RTS);
1346 
1347 	switch (how) {
1348 	case TIOCMBIC:
1349 		CLR(sc->sc_mcr, combits);
1350 		break;
1351 
1352 	case TIOCMBIS:
1353 		SET(sc->sc_mcr, combits);
1354 		break;
1355 
1356 	case TIOCMSET:
1357 		CLR(sc->sc_mcr, MCR_DTR | MCR_RTS);
1358 		SET(sc->sc_mcr, combits);
1359 		break;
1360 	}
1361 
1362 	if (!sc->sc_heldchange) {
1363 		if (sc->sc_tx_busy) {
1364 			sc->sc_heldtbc = sc->sc_tbc;
1365 			sc->sc_tbc = 0;
1366 			sc->sc_heldchange = 1;
1367 		} else
1368 			com_loadchannelregs(sc);
1369 	}
1370 }
1371 
1372 int
1373 com_to_tiocm(struct com_softc *sc)
1374 {
1375 	u_char combits;
1376 	int ttybits = 0;
1377 
1378 	combits = sc->sc_mcr;
1379 	if (ISSET(combits, MCR_DTR))
1380 		SET(ttybits, TIOCM_DTR);
1381 	if (ISSET(combits, MCR_RTS))
1382 		SET(ttybits, TIOCM_RTS);
1383 
1384 	combits = sc->sc_msr;
1385 	if (sc->sc_type == COM_TYPE_INGENIC) {
1386 		SET(ttybits, TIOCM_CD);
1387 	} else {
1388 		if (ISSET(combits, MSR_DCD))
1389 			SET(ttybits, TIOCM_CD);
1390 	}
1391 	if (ISSET(combits, MSR_CTS))
1392 		SET(ttybits, TIOCM_CTS);
1393 	if (ISSET(combits, MSR_DSR))
1394 		SET(ttybits, TIOCM_DSR);
1395 	if (ISSET(combits, MSR_RI | MSR_TERI))
1396 		SET(ttybits, TIOCM_RI);
1397 
1398 	if (ISSET(sc->sc_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS | IER_EMSC))
1399 		SET(ttybits, TIOCM_LE);
1400 
1401 	return (ttybits);
1402 }
1403 
1404 static u_char
1405 cflag2lcr(tcflag_t cflag)
1406 {
1407 	u_char lcr = 0;
1408 
1409 	switch (ISSET(cflag, CSIZE)) {
1410 	case CS5:
1411 		SET(lcr, LCR_5BITS);
1412 		break;
1413 	case CS6:
1414 		SET(lcr, LCR_6BITS);
1415 		break;
1416 	case CS7:
1417 		SET(lcr, LCR_7BITS);
1418 		break;
1419 	case CS8:
1420 		SET(lcr, LCR_8BITS);
1421 		break;
1422 	}
1423 	if (ISSET(cflag, PARENB)) {
1424 		SET(lcr, LCR_PENAB);
1425 		if (!ISSET(cflag, PARODD))
1426 			SET(lcr, LCR_PEVEN);
1427 	}
1428 	if (ISSET(cflag, CSTOPB))
1429 		SET(lcr, LCR_STOPB);
1430 
1431 	return (lcr);
1432 }
1433 
1434 int
1435 comparam(struct tty *tp, struct termios *t)
1436 {
1437 	struct com_softc *sc =
1438 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1439 	int ospeed;
1440 	u_char lcr;
1441 
1442 	if (COM_ISALIVE(sc) == 0)
1443 		return (EIO);
1444 
1445 	if (sc->sc_type == COM_TYPE_HAYESP) {
1446 		int prescaler, speed;
1447 
1448 		/*
1449 		 * Calculate UART clock prescaler.  It should be in
1450 		 * range of 0 .. 3.
1451 		 */
1452 		for (prescaler = 0, speed = t->c_ospeed; prescaler < 4;
1453 		    prescaler++, speed /= 2)
1454 			if ((ospeed = comspeed(speed, sc->sc_frequency,
1455 					       sc->sc_type)) > 0)
1456 				break;
1457 
1458 		if (prescaler == 4)
1459 			return (EINVAL);
1460 		sc->sc_prescaler = prescaler;
1461 	} else
1462 		ospeed = comspeed(t->c_ospeed, sc->sc_frequency, sc->sc_type);
1463 
1464 	/* Check requested parameters. */
1465 	if (ospeed < 0)
1466 		return (EINVAL);
1467 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
1468 		return (EINVAL);
1469 
1470 	/*
1471 	 * For the console, always force CLOCAL and !HUPCL, so that the port
1472 	 * is always active.
1473 	 */
1474 	if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
1475 	    ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
1476 		SET(t->c_cflag, CLOCAL);
1477 		CLR(t->c_cflag, HUPCL);
1478 	}
1479 
1480 	/*
1481 	 * If there were no changes, don't do anything.  This avoids dropping
1482 	 * input and improves performance when all we did was frob things like
1483 	 * VMIN and VTIME.
1484 	 */
1485 	if (tp->t_ospeed == t->c_ospeed &&
1486 	    tp->t_cflag == t->c_cflag)
1487 		return (0);
1488 
1489 	lcr = ISSET(sc->sc_lcr, LCR_SBREAK) | cflag2lcr(t->c_cflag);
1490 
1491 	mutex_spin_enter(&sc->sc_lock);
1492 
1493 	sc->sc_lcr = lcr;
1494 
1495 	/*
1496 	 * If we're not in a mode that assumes a connection is present, then
1497 	 * ignore carrier changes.
1498 	 */
1499 	if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
1500 		sc->sc_msr_dcd = 0;
1501 	else
1502 		sc->sc_msr_dcd = MSR_DCD;
1503 	/*
1504 	 * Set the flow control pins depending on the current flow control
1505 	 * mode.
1506 	 */
1507 	if (ISSET(t->c_cflag, CRTSCTS)) {
1508 		sc->sc_mcr_dtr = MCR_DTR;
1509 		sc->sc_mcr_rts = MCR_RTS;
1510 		sc->sc_msr_cts = MSR_CTS;
1511 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1512 			SET(sc->sc_mcr, MCR_AFE);
1513 		} else {
1514 			sc->sc_efr = EFR_AUTORTS | EFR_AUTOCTS;
1515 		}
1516 	} else if (ISSET(t->c_cflag, MDMBUF)) {
1517 		/*
1518 		 * For DTR/DCD flow control, make sure we don't toggle DTR for
1519 		 * carrier detection.
1520 		 */
1521 		sc->sc_mcr_dtr = 0;
1522 		sc->sc_mcr_rts = MCR_DTR;
1523 		sc->sc_msr_cts = MSR_DCD;
1524 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1525 			CLR(sc->sc_mcr, MCR_AFE);
1526 		} else {
1527 			sc->sc_efr = 0;
1528 		}
1529 	} else {
1530 		/*
1531 		 * If no flow control, then always set RTS.  This will make
1532 		 * the other side happy if it mistakenly thinks we're doing
1533 		 * RTS/CTS flow control.
1534 		 */
1535 		sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
1536 		sc->sc_mcr_rts = 0;
1537 		sc->sc_msr_cts = 0;
1538 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1539 			CLR(sc->sc_mcr, MCR_AFE);
1540 		} else {
1541 			sc->sc_efr = 0;
1542 		}
1543 		if (ISSET(sc->sc_mcr, MCR_DTR))
1544 			SET(sc->sc_mcr, MCR_RTS);
1545 		else
1546 			CLR(sc->sc_mcr, MCR_RTS);
1547 	}
1548 	sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;
1549 
1550 	if (t->c_ospeed == 0 && tp->t_ospeed != 0)
1551 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1552 	else if (t->c_ospeed != 0 && tp->t_ospeed == 0)
1553 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1554 
1555 	sc->sc_dlbl = ospeed;
1556 	sc->sc_dlbh = ospeed >> 8;
1557 
1558 	/*
1559 	 * Set the FIFO threshold based on the receive speed.
1560 	 *
1561 	 *  * If it's a low speed, it's probably a mouse or some other
1562 	 *    interactive device, so set the threshold low.
1563 	 *  * If it's a high speed, trim the trigger level down to prevent
1564 	 *    overflows.
1565 	 *  * Otherwise set it a bit higher.
1566 	 */
1567 	if (sc->sc_type == COM_TYPE_HAYESP) {
1568 		sc->sc_fifo = FIFO_DMA_MODE | FIFO_ENABLE | FIFO_TRIGGER_8;
1569 	} else if (sc->sc_type == COM_TYPE_TEGRA) {
1570 		sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
1571 	} else if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
1572 		if (t->c_ospeed <= 1200)
1573 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
1574 		else if (t->c_ospeed <= 38400)
1575 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_8;
1576 		else
1577 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_4;
1578 	} else {
1579 		sc->sc_fifo = 0;
1580 	}
1581 
1582 	if (sc->sc_type == COM_TYPE_INGENIC)
1583 		sc->sc_fifo |= FIFO_UART_ON;
1584 
1585 	/* And copy to tty. */
1586 	tp->t_ispeed = t->c_ospeed;
1587 	tp->t_ospeed = t->c_ospeed;
1588 	tp->t_cflag = t->c_cflag;
1589 
1590 	if (!sc->sc_heldchange) {
1591 		if (sc->sc_tx_busy) {
1592 			sc->sc_heldtbc = sc->sc_tbc;
1593 			sc->sc_tbc = 0;
1594 			sc->sc_heldchange = 1;
1595 		} else
1596 			com_loadchannelregs(sc);
1597 	}
1598 
1599 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1600 		/* Disable the high water mark. */
1601 		sc->sc_r_hiwat = 0;
1602 		sc->sc_r_lowat = 0;
1603 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1604 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1605 			com_schedrx(sc);
1606 		}
1607 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
1608 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
1609 			com_hwiflow(sc);
1610 		}
1611 	} else {
1612 		sc->sc_r_hiwat = com_rbuf_hiwat;
1613 		sc->sc_r_lowat = com_rbuf_lowat;
1614 	}
1615 
1616 	mutex_spin_exit(&sc->sc_lock);
1617 
1618 	/*
1619 	 * Update the tty layer's idea of the carrier bit, in case we changed
1620 	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
1621 	 * explicit request.
1622 	 */
1623 	if (sc->sc_type == COM_TYPE_INGENIC) {
1624 		/* no DCD here */
1625 		(void) (*tp->t_linesw->l_modem)(tp, 1);
1626 	} else
1627 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, MSR_DCD));
1628 
1629 #ifdef COM_DEBUG
1630 	if (com_debug)
1631 		comstatus(sc, "comparam ");
1632 #endif
1633 
1634 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1635 		if (sc->sc_tx_stopped) {
1636 			sc->sc_tx_stopped = 0;
1637 			comstart(tp);
1638 		}
1639 	}
1640 
1641 	return (0);
1642 }
1643 
1644 void
1645 com_iflush(struct com_softc *sc)
1646 {
1647 	struct com_regs	*regsp = &sc->sc_regs;
1648 	uint8_t fifo;
1649 #ifdef DIAGNOSTIC
1650 	int reg;
1651 #endif
1652 	int timo;
1653 
1654 #ifdef DIAGNOSTIC
1655 	reg = 0xffff;
1656 #endif
1657 	timo = 50000;
1658 	/* flush any pending I/O */
1659 	while (ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)
1660 	    && --timo)
1661 #ifdef DIAGNOSTIC
1662 		reg =
1663 #else
1664 		    (void)
1665 #endif
1666 		    CSR_READ_1(regsp, COM_REG_RXDATA);
1667 #ifdef DIAGNOSTIC
1668 	if (!timo)
1669 		aprint_error_dev(sc->sc_dev, "com_iflush timeout %02x\n", reg);
1670 #endif
1671 
1672 	switch (sc->sc_type) {
1673 	case COM_TYPE_16750:
1674 	case COM_TYPE_DW_APB:
1675 		/*
1676 		 * Reset all Rx/Tx FIFO, preserve current FIFO length.
1677 		 * This should prevent triggering busy interrupt while
1678 		 * manipulating divisors.
1679 		 */
1680 		fifo = CSR_READ_1(regsp, COM_REG_FIFO) & (FIFO_TRIGGER_1 |
1681 		    FIFO_TRIGGER_4 | FIFO_TRIGGER_8 | FIFO_TRIGGER_14);
1682 		CSR_WRITE_1(regsp, COM_REG_FIFO,
1683 		    fifo | FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST);
1684 		delay(100);
1685 		break;
1686 	}
1687 }
1688 
1689 void
1690 com_loadchannelregs(struct com_softc *sc)
1691 {
1692 	struct com_regs *regsp = &sc->sc_regs;
1693 
1694 	/* XXXXX necessary? */
1695 	com_iflush(sc);
1696 
1697 	if (sc->sc_type == COM_TYPE_PXA2x0)
1698 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
1699 	else
1700 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
1701 
1702 	if (sc->sc_type == COM_TYPE_OMAP) {
1703 		/* disable before changing settings */
1704 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
1705 	}
1706 
1707 	if (ISSET(sc->sc_hwflags, COM_HW_FLOW)) {
1708 		KASSERT(sc->sc_type != COM_TYPE_AU1x00);
1709 		KASSERT(sc->sc_type != COM_TYPE_16550_NOERS);
1710 		/* no EFR on alchemy */
1711 		CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
1712 		CSR_WRITE_1(regsp, COM_REG_EFR, sc->sc_efr);
1713 	}
1714 	if (sc->sc_type == COM_TYPE_AU1x00) {
1715 		/* alchemy has single separate 16-bit clock divisor register */
1716 		CSR_WRITE_2(regsp, COM_REG_DLBL, sc->sc_dlbl +
1717 		    (sc->sc_dlbh << 8));
1718 	} else {
1719 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
1720 		CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
1721 		CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
1722 	}
1723 	CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
1724 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active = sc->sc_mcr);
1725 	CSR_WRITE_1(regsp, COM_REG_FIFO, sc->sc_fifo);
1726 	if (sc->sc_type == COM_TYPE_HAYESP) {
1727 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
1728 		    HAYESP_SETPRESCALER);
1729 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
1730 		    sc->sc_prescaler);
1731 	}
1732 	if (sc->sc_type == COM_TYPE_OMAP) {
1733 		/* setup the fifos.  the FCR value is not used as long
1734 		   as SCR[6] and SCR[7] are 0, which they are at reset
1735 		   and we never touch the SCR register */
1736 		uint8_t rx_fifo_trig = 40;
1737 		uint8_t tx_fifo_trig = 60;
1738 		uint8_t rx_start = 8;
1739 		uint8_t rx_halt = 60;
1740 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
1741 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
1742 
1743 		/* enable access to TCR & TLR */
1744 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr | MCR_TCR_TLR);
1745 
1746 		/* write tcr and tlr values */
1747 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
1748 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
1749 
1750 		/* disable access to TCR & TLR */
1751 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr);
1752 
1753 		/* enable again, but mode is based on speed */
1754 		if (sc->sc_tty->t_termios.c_ospeed > 230400) {
1755 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
1756 		} else {
1757 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
1758 		}
1759 	}
1760 
1761 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1762 }
1763 
1764 int
1765 comhwiflow(struct tty *tp, int block)
1766 {
1767 	struct com_softc *sc =
1768 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1769 
1770 	if (COM_ISALIVE(sc) == 0)
1771 		return (0);
1772 
1773 	if (sc->sc_mcr_rts == 0)
1774 		return (0);
1775 
1776 	mutex_spin_enter(&sc->sc_lock);
1777 
1778 	if (block) {
1779 		if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1780 			SET(sc->sc_rx_flags, RX_TTY_BLOCKED);
1781 			com_hwiflow(sc);
1782 		}
1783 	} else {
1784 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1785 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1786 			com_schedrx(sc);
1787 		}
1788 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1789 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED);
1790 			com_hwiflow(sc);
1791 		}
1792 	}
1793 
1794 	mutex_spin_exit(&sc->sc_lock);
1795 	return (1);
1796 }
1797 
1798 /*
1799  * (un)block input via hw flowcontrol
1800  */
1801 void
1802 com_hwiflow(struct com_softc *sc)
1803 {
1804 	struct com_regs *regsp= &sc->sc_regs;
1805 
1806 	if (sc->sc_mcr_rts == 0)
1807 		return;
1808 
1809 	if (ISSET(sc->sc_rx_flags, RX_ANY_BLOCK)) {
1810 		CLR(sc->sc_mcr, sc->sc_mcr_rts);
1811 		CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
1812 	} else {
1813 		SET(sc->sc_mcr, sc->sc_mcr_rts);
1814 		SET(sc->sc_mcr_active, sc->sc_mcr_rts);
1815 	}
1816 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active);
1817 }
1818 
1819 
1820 void
1821 comstart(struct tty *tp)
1822 {
1823 	struct com_softc *sc =
1824 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1825 	struct com_regs *regsp = &sc->sc_regs;
1826 	int s;
1827 
1828 	if (COM_ISALIVE(sc) == 0)
1829 		return;
1830 
1831 	s = spltty();
1832 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
1833 		goto out;
1834 	if (sc->sc_tx_stopped)
1835 		goto out;
1836 	if (!ttypull(tp))
1837 		goto out;
1838 
1839 	/* Grab the first contiguous region of buffer space. */
1840 	{
1841 		u_char *tba;
1842 		int tbc;
1843 
1844 		tba = tp->t_outq.c_cf;
1845 		tbc = ndqb(&tp->t_outq, 0);
1846 
1847 		mutex_spin_enter(&sc->sc_lock);
1848 
1849 		sc->sc_tba = tba;
1850 		sc->sc_tbc = tbc;
1851 	}
1852 
1853 	SET(tp->t_state, TS_BUSY);
1854 	sc->sc_tx_busy = 1;
1855 
1856 	/* Enable transmit completion interrupts if necessary. */
1857 	if (!ISSET(sc->sc_ier, IER_ETXRDY)) {
1858 		SET(sc->sc_ier, IER_ETXRDY);
1859 		CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1860 	}
1861 
1862 	/* Output the first chunk of the contiguous buffer. */
1863 	if (!ISSET(sc->sc_hwflags, COM_HW_NO_TXPRELOAD)) {
1864 		u_int n;
1865 
1866 		n = sc->sc_tbc;
1867 		if (n > sc->sc_fifolen)
1868 			n = sc->sc_fifolen;
1869 		CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
1870 		sc->sc_tbc -= n;
1871 		sc->sc_tba += n;
1872 	}
1873 
1874 	mutex_spin_exit(&sc->sc_lock);
1875 out:
1876 	splx(s);
1877 	return;
1878 }
1879 
1880 /*
1881  * Stop output on a line.
1882  */
1883 void
1884 comstop(struct tty *tp, int flag)
1885 {
1886 	struct com_softc *sc =
1887 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1888 
1889 	mutex_spin_enter(&sc->sc_lock);
1890 	if (ISSET(tp->t_state, TS_BUSY)) {
1891 		/* Stop transmitting at the next chunk. */
1892 		sc->sc_tbc = 0;
1893 		sc->sc_heldtbc = 0;
1894 		if (!ISSET(tp->t_state, TS_TTSTOP))
1895 			SET(tp->t_state, TS_FLUSH);
1896 	}
1897 	mutex_spin_exit(&sc->sc_lock);
1898 }
1899 
1900 void
1901 comdiag(void *arg)
1902 {
1903 	struct com_softc *sc = arg;
1904 	int overflows, floods;
1905 
1906 	mutex_spin_enter(&sc->sc_lock);
1907 	overflows = sc->sc_overflows;
1908 	sc->sc_overflows = 0;
1909 	floods = sc->sc_floods;
1910 	sc->sc_floods = 0;
1911 	sc->sc_errors = 0;
1912 	mutex_spin_exit(&sc->sc_lock);
1913 
1914 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
1915 	    device_xname(sc->sc_dev),
1916 	    overflows, overflows == 1 ? "" : "s",
1917 	    floods, floods == 1 ? "" : "s");
1918 }
1919 
1920 integrate void
1921 com_rxsoft(struct com_softc *sc, struct tty *tp)
1922 {
1923 	int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
1924 	u_char *get, *end;
1925 	u_int cc, scc;
1926 	u_char lsr;
1927 	int code;
1928 
1929 	end = sc->sc_ebuf;
1930 	get = sc->sc_rbget;
1931 	scc = cc = com_rbuf_size - sc->sc_rbavail;
1932 
1933 	if (cc == com_rbuf_size) {
1934 		sc->sc_floods++;
1935 		if (sc->sc_errors++ == 0)
1936 			callout_reset(&sc->sc_diag_callout, 60 * hz,
1937 			    comdiag, sc);
1938 	}
1939 
1940 	/* If not yet open, drop the entire buffer content here */
1941 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
1942 		get += cc << 1;
1943 		if (get >= end)
1944 			get -= com_rbuf_size << 1;
1945 		cc = 0;
1946 	}
1947 	while (cc) {
1948 		code = get[0];
1949 		lsr = get[1];
1950 		if (ISSET(lsr, LSR_OE | LSR_BI | LSR_FE | LSR_PE)) {
1951 			if (ISSET(lsr, LSR_OE)) {
1952 				sc->sc_overflows++;
1953 				if (sc->sc_errors++ == 0)
1954 					callout_reset(&sc->sc_diag_callout,
1955 					    60 * hz, comdiag, sc);
1956 			}
1957 			if (ISSET(lsr, LSR_BI | LSR_FE))
1958 				SET(code, TTY_FE);
1959 			if (ISSET(lsr, LSR_PE))
1960 				SET(code, TTY_PE);
1961 		}
1962 		if ((*rint)(code, tp) == -1) {
1963 			/*
1964 			 * The line discipline's buffer is out of space.
1965 			 */
1966 			if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1967 				/*
1968 				 * We're either not using flow control, or the
1969 				 * line discipline didn't tell us to block for
1970 				 * some reason.  Either way, we have no way to
1971 				 * know when there's more space available, so
1972 				 * just drop the rest of the data.
1973 				 */
1974 				get += cc << 1;
1975 				if (get >= end)
1976 					get -= com_rbuf_size << 1;
1977 				cc = 0;
1978 			} else {
1979 				/*
1980 				 * Don't schedule any more receive processing
1981 				 * until the line discipline tells us there's
1982 				 * space available (through comhwiflow()).
1983 				 * Leave the rest of the data in the input
1984 				 * buffer.
1985 				 */
1986 				SET(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1987 			}
1988 			break;
1989 		}
1990 		get += 2;
1991 		if (get >= end)
1992 			get = sc->sc_rbuf;
1993 		cc--;
1994 	}
1995 
1996 	if (cc != scc) {
1997 		sc->sc_rbget = get;
1998 		mutex_spin_enter(&sc->sc_lock);
1999 
2000 		cc = sc->sc_rbavail += scc - cc;
2001 		/* Buffers should be ok again, release possible block. */
2002 		if (cc >= sc->sc_r_lowat) {
2003 			if (ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
2004 				CLR(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
2005 				SET(sc->sc_ier, IER_ERXRDY);
2006 				if (sc->sc_type == COM_TYPE_PXA2x0)
2007 					SET(sc->sc_ier, IER_ERXTOUT);
2008 				if (sc->sc_type == COM_TYPE_INGENIC ||
2009 				    sc->sc_type == COM_TYPE_TEGRA)
2010 					SET(sc->sc_ier, IER_ERXTOUT);
2011 
2012 				CSR_WRITE_1(&sc->sc_regs, COM_REG_IER,
2013 				    sc->sc_ier);
2014 			}
2015 			if (ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED)) {
2016 				CLR(sc->sc_rx_flags, RX_IBUF_BLOCKED);
2017 				com_hwiflow(sc);
2018 			}
2019 		}
2020 		mutex_spin_exit(&sc->sc_lock);
2021 	}
2022 }
2023 
2024 integrate void
2025 com_txsoft(struct com_softc *sc, struct tty *tp)
2026 {
2027 
2028 	CLR(tp->t_state, TS_BUSY);
2029 	if (ISSET(tp->t_state, TS_FLUSH))
2030 		CLR(tp->t_state, TS_FLUSH);
2031 	else
2032 		ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
2033 	(*tp->t_linesw->l_start)(tp);
2034 }
2035 
2036 integrate void
2037 com_stsoft(struct com_softc *sc, struct tty *tp)
2038 {
2039 	u_char msr, delta;
2040 
2041 	mutex_spin_enter(&sc->sc_lock);
2042 	msr = sc->sc_msr;
2043 	delta = sc->sc_msr_delta;
2044 	sc->sc_msr_delta = 0;
2045 	mutex_spin_exit(&sc->sc_lock);
2046 
2047 	if (ISSET(delta, sc->sc_msr_dcd)) {
2048 		/*
2049 		 * Inform the tty layer that carrier detect changed.
2050 		 */
2051 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(msr, MSR_DCD));
2052 	}
2053 
2054 	if (ISSET(delta, sc->sc_msr_cts)) {
2055 		/* Block or unblock output according to flow control. */
2056 		if (ISSET(msr, sc->sc_msr_cts)) {
2057 			sc->sc_tx_stopped = 0;
2058 			(*tp->t_linesw->l_start)(tp);
2059 		} else {
2060 			sc->sc_tx_stopped = 1;
2061 		}
2062 	}
2063 
2064 #ifdef COM_DEBUG
2065 	if (com_debug)
2066 		comstatus(sc, "com_stsoft");
2067 #endif
2068 }
2069 
2070 void
2071 comsoft(void *arg)
2072 {
2073 	struct com_softc *sc = arg;
2074 	struct tty *tp;
2075 
2076 	if (COM_ISALIVE(sc) == 0)
2077 		return;
2078 
2079 	tp = sc->sc_tty;
2080 
2081 	if (sc->sc_rx_ready) {
2082 		sc->sc_rx_ready = 0;
2083 		com_rxsoft(sc, tp);
2084 	}
2085 
2086 	if (sc->sc_st_check) {
2087 		sc->sc_st_check = 0;
2088 		com_stsoft(sc, tp);
2089 	}
2090 
2091 	if (sc->sc_tx_done) {
2092 		sc->sc_tx_done = 0;
2093 		com_txsoft(sc, tp);
2094 	}
2095 }
2096 
2097 int
2098 comintr(void *arg)
2099 {
2100 	struct com_softc *sc = arg;
2101 	struct com_regs *regsp = &sc->sc_regs;
2102 
2103 	u_char *put, *end;
2104 	u_int cc;
2105 	u_char lsr, iir;
2106 
2107 	if (COM_ISALIVE(sc) == 0)
2108 		return (0);
2109 
2110 	KASSERT(regsp != NULL);
2111 
2112 	mutex_spin_enter(&sc->sc_lock);
2113 	iir = CSR_READ_1(regsp, COM_REG_IIR);
2114 
2115 	/* Handle ns16750-specific busy interrupt. */
2116 	if (sc->sc_type == COM_TYPE_16750 &&
2117 	    (iir & IIR_BUSY) == IIR_BUSY) {
2118 		for (int timeout = 10000;
2119 		    (CSR_READ_1(regsp, COM_REG_USR) & 0x1) != 0; timeout--)
2120 			if (timeout <= 0) {
2121 				aprint_error_dev(sc->sc_dev,
2122 				    "timeout while waiting for BUSY interrupt "
2123 				    "acknowledge\n");
2124 				mutex_spin_exit(&sc->sc_lock);
2125 				return (0);
2126 			}
2127 
2128 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2129 		iir = CSR_READ_1(regsp, COM_REG_IIR);
2130 	}
2131 
2132 	/* DesignWare APB UART BUSY interrupt */
2133 	if (sc->sc_type == COM_TYPE_DW_APB &&
2134 	    (iir & IIR_BUSY) == IIR_BUSY) {
2135 		if ((CSR_READ_1(regsp, COM_REG_USR) & 0x1) != 0) {
2136 			CSR_WRITE_1(regsp, COM_REG_HALT, HALT_CHCFG_EN);
2137 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
2138 			CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
2139 			CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
2140 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2141 			CSR_WRITE_1(regsp, COM_REG_HALT,
2142 			    HALT_CHCFG_EN | HALT_CHCFG_UD);
2143 			for (int timeout = 10000000;
2144 			    (CSR_READ_1(regsp, COM_REG_HALT) & HALT_CHCFG_UD) != 0;
2145 			    timeout--) {
2146 				if (timeout <= 0) {
2147 					aprint_error_dev(sc->sc_dev,
2148 					    "timeout while waiting for HALT "
2149 					    "update acknowledge 0x%x 0x%x\n",
2150 					    CSR_READ_1(regsp, COM_REG_HALT),
2151 					    CSR_READ_1(regsp, COM_REG_USR));
2152 					break;
2153 				}
2154 			}
2155 			CSR_WRITE_1(regsp, COM_REG_HALT, 0);
2156 			(void)CSR_READ_1(regsp, COM_REG_USR);
2157 		} else {
2158 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
2159 			CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
2160 			CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
2161 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2162 		}
2163 	}
2164 
2165 	end = sc->sc_ebuf;
2166 	put = sc->sc_rbput;
2167 	cc = sc->sc_rbavail;
2168 
2169 	if (ISSET(iir, IIR_NOPEND)) {
2170 		if (ISSET(sc->sc_hwflags, COM_HW_BROKEN_ETXRDY))
2171 			goto do_tx;
2172 		mutex_spin_exit(&sc->sc_lock);
2173 		return (0);
2174 	}
2175 
2176 again:	do {
2177 		u_char	msr, delta;
2178 
2179 		lsr = CSR_READ_1(regsp, COM_REG_LSR);
2180 		if (ISSET(lsr, LSR_BI)) {
2181 			int cn_trapped = 0; /* see above: cn_trap() */
2182 
2183 			cn_check_magic(sc->sc_tty->t_dev,
2184 				       CNC_BREAK, com_cnm_state);
2185 			if (cn_trapped)
2186 				continue;
2187 #if defined(KGDB) && !defined(DDB)
2188 			if (ISSET(sc->sc_hwflags, COM_HW_KGDB)) {
2189 				kgdb_connect(1);
2190 				continue;
2191 			}
2192 #endif
2193 		}
2194 
2195 		if (sc->sc_type == COM_TYPE_BCMAUXUART && ISSET(iir, IIR_RXRDY))
2196 			lsr |= LSR_RXRDY;
2197 
2198 		if (ISSET(lsr, LSR_RCV_MASK) &&
2199 		    !ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
2200 			while (cc > 0) {
2201 				int cn_trapped = 0;
2202 				put[0] = CSR_READ_1(regsp, COM_REG_RXDATA);
2203 				put[1] = lsr;
2204 				cn_check_magic(sc->sc_tty->t_dev,
2205 					       put[0], com_cnm_state);
2206 				if (cn_trapped)
2207 					goto next;
2208 				put += 2;
2209 				if (put >= end)
2210 					put = sc->sc_rbuf;
2211 				cc--;
2212 			next:
2213 				lsr = CSR_READ_1(regsp, COM_REG_LSR);
2214 				if (!ISSET(lsr, LSR_RCV_MASK))
2215 					break;
2216 			}
2217 
2218 			/*
2219 			 * Current string of incoming characters ended because
2220 			 * no more data was available or we ran out of space.
2221 			 * Schedule a receive event if any data was received.
2222 			 * If we're out of space, turn off receive interrupts.
2223 			 */
2224 			sc->sc_rbput = put;
2225 			sc->sc_rbavail = cc;
2226 			if (!ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED))
2227 				sc->sc_rx_ready = 1;
2228 
2229 			/*
2230 			 * See if we are in danger of overflowing a buffer. If
2231 			 * so, use hardware flow control to ease the pressure.
2232 			 */
2233 			if (!ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED) &&
2234 			    cc < sc->sc_r_hiwat) {
2235 				SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
2236 				com_hwiflow(sc);
2237 			}
2238 
2239 			/*
2240 			 * If we're out of space, disable receive interrupts
2241 			 * until the queue has drained a bit.
2242 			 */
2243 			if (!cc) {
2244 				SET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
2245 				switch (sc->sc_type) {
2246 				case COM_TYPE_PXA2x0:
2247 					CLR(sc->sc_ier, IER_ERXRDY|IER_ERXTOUT);
2248 					break;
2249 				case COM_TYPE_INGENIC:
2250 				case COM_TYPE_TEGRA:
2251 					CLR(sc->sc_ier,
2252 					    IER_ERXRDY | IER_ERXTOUT);
2253 					break;
2254 				default:
2255 					CLR(sc->sc_ier, IER_ERXRDY);
2256 					break;
2257 				}
2258 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
2259 			}
2260 		} else {
2261 			if ((iir & (IIR_RXRDY|IIR_TXRDY)) == IIR_RXRDY) {
2262 				(void) CSR_READ_1(regsp, COM_REG_RXDATA);
2263 				continue;
2264 			}
2265 		}
2266 
2267 		msr = CSR_READ_1(regsp, COM_REG_MSR);
2268 		delta = msr ^ sc->sc_msr;
2269 		sc->sc_msr = msr;
2270 		if ((sc->sc_pps_state.ppsparam.mode & PPS_CAPTUREBOTH) &&
2271 		    (delta & MSR_DCD)) {
2272 			mutex_spin_enter(&timecounter_lock);
2273 			pps_capture(&sc->sc_pps_state);
2274 			pps_event(&sc->sc_pps_state,
2275 			    (msr & MSR_DCD) ?
2276 			    PPS_CAPTUREASSERT :
2277 			    PPS_CAPTURECLEAR);
2278 			mutex_spin_exit(&timecounter_lock);
2279 		}
2280 
2281 		/*
2282 		 * Process normal status changes
2283 		 */
2284 		if (ISSET(delta, sc->sc_msr_mask)) {
2285 			SET(sc->sc_msr_delta, delta);
2286 
2287 			/*
2288 			 * Stop output immediately if we lose the output
2289 			 * flow control signal or carrier detect.
2290 			 */
2291 			if (ISSET(~msr, sc->sc_msr_mask)) {
2292 				sc->sc_tbc = 0;
2293 				sc->sc_heldtbc = 0;
2294 #ifdef COM_DEBUG
2295 				if (com_debug)
2296 					comstatus(sc, "comintr  ");
2297 #endif
2298 			}
2299 
2300 			sc->sc_st_check = 1;
2301 		}
2302 	} while (!ISSET((iir =
2303 	    CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND) &&
2304 	    /*
2305 	     * Since some device (e.g., ST16C1550) doesn't clear IIR_TXRDY
2306 	     * by IIR read, so we can't do this way: `process all interrupts,
2307 	     * then do TX if possible'.
2308 	     */
2309 	    (iir & IIR_IMASK) != IIR_TXRDY);
2310 
2311 do_tx:
2312 	/*
2313 	 * Read LSR again, since there may be an interrupt between
2314 	 * the last LSR read and IIR read above.
2315 	 */
2316 	lsr = CSR_READ_1(regsp, COM_REG_LSR);
2317 
2318 	/*
2319 	 * See if data can be transmitted as well.
2320 	 * Schedule tx done event if no data left
2321 	 * and tty was marked busy.
2322 	 */
2323 	if (ISSET(lsr, LSR_TXRDY)) {
2324 		/*
2325 		 * If we've delayed a parameter change, do it now, and restart
2326 		 * output.
2327 		 */
2328 		if (sc->sc_heldchange) {
2329 			com_loadchannelregs(sc);
2330 			sc->sc_heldchange = 0;
2331 			sc->sc_tbc = sc->sc_heldtbc;
2332 			sc->sc_heldtbc = 0;
2333 		}
2334 
2335 		/* Output the next chunk of the contiguous buffer, if any. */
2336 		if (sc->sc_tbc > 0) {
2337 			u_int n;
2338 
2339 			n = sc->sc_tbc;
2340 			if (n > sc->sc_fifolen)
2341 				n = sc->sc_fifolen;
2342 			CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
2343 			sc->sc_tbc -= n;
2344 			sc->sc_tba += n;
2345 		} else {
2346 			/* Disable transmit completion interrupts if necessary. */
2347 			if (ISSET(sc->sc_ier, IER_ETXRDY)) {
2348 				CLR(sc->sc_ier, IER_ETXRDY);
2349 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
2350 			}
2351 			if (sc->sc_tx_busy) {
2352 				sc->sc_tx_busy = 0;
2353 				sc->sc_tx_done = 1;
2354 			}
2355 		}
2356 	}
2357 
2358 	if (!ISSET((iir = CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND))
2359 		goto again;
2360 
2361 	mutex_spin_exit(&sc->sc_lock);
2362 
2363 	/* Wake up the poller. */
2364 	if ((sc->sc_rx_ready | sc->sc_st_check | sc->sc_tx_done) != 0)
2365 		softint_schedule(sc->sc_si);
2366 
2367 #ifdef RND_COM
2368 	rnd_add_uint32(&sc->rnd_source, iir | lsr);
2369 #endif
2370 
2371 	return (1);
2372 }
2373 
2374 /*
2375  * The following functions are polled getc and putc routines, shared
2376  * by the console and kgdb glue.
2377  *
2378  * The read-ahead code is so that you can detect pending in-band
2379  * cn_magic in polled mode while doing output rather than having to
2380  * wait until the kernel decides it needs input.
2381  */
2382 
2383 #define MAX_READAHEAD	20
2384 static int com_readahead[MAX_READAHEAD];
2385 static int com_readaheadcount = 0;
2386 
2387 int
2388 com_common_getc(dev_t dev, struct com_regs *regsp)
2389 {
2390 	int s = splserial();
2391 	u_char stat, c;
2392 
2393 	/* got a character from reading things earlier */
2394 	if (com_readaheadcount > 0) {
2395 		int i;
2396 
2397 		c = com_readahead[0];
2398 		for (i = 1; i < com_readaheadcount; i++) {
2399 			com_readahead[i-1] = com_readahead[i];
2400 		}
2401 		com_readaheadcount--;
2402 		splx(s);
2403 		return (c);
2404 	}
2405 
2406 	/* don't block until a character becomes available */
2407 	if (!ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
2408 		splx(s);
2409 		return -1;
2410 	}
2411 
2412 	c = CSR_READ_1(regsp, COM_REG_RXDATA);
2413 	stat = CSR_READ_1(regsp, COM_REG_IIR);
2414 	{
2415 		int cn_trapped = 0;	/* required by cn_trap, see above */
2416 #ifdef DDB
2417 		extern int db_active;
2418 		if (!db_active)
2419 #endif
2420 			cn_check_magic(dev, c, com_cnm_state);
2421 	}
2422 	splx(s);
2423 	return (c);
2424 }
2425 
2426 static void
2427 com_common_putc(dev_t dev, struct com_regs *regsp, int c, int with_readahead)
2428 {
2429 	int s = splserial();
2430 	int cin, stat, timo;
2431 
2432 	if (with_readahead && com_readaheadcount < MAX_READAHEAD
2433 	     && ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
2434 		int cn_trapped = 0;
2435 		cin = CSR_READ_1(regsp, COM_REG_RXDATA);
2436 		stat = CSR_READ_1(regsp, COM_REG_IIR);
2437 		cn_check_magic(dev, cin, com_cnm_state);
2438 		com_readahead[com_readaheadcount++] = cin;
2439 	}
2440 
2441 	/* wait for any pending transmission to finish */
2442 	timo = 150000;
2443 	while (!ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_TXRDY) && --timo)
2444 		continue;
2445 
2446 	CSR_WRITE_1(regsp, COM_REG_TXDATA, c);
2447 	COM_BARRIER(regsp, BR | BW);
2448 
2449 	splx(s);
2450 }
2451 
2452 /*
2453  * Initialize UART for use as console or KGDB line.
2454  */
2455 int
2456 cominit(struct com_regs *regsp, int rate, int frequency, int type,
2457     tcflag_t cflag)
2458 {
2459 
2460 	if (bus_space_map(regsp->cr_iot, regsp->cr_iobase, regsp->cr_nports, 0,
2461 		&regsp->cr_ioh))
2462 		return (ENOMEM); /* ??? */
2463 
2464 	if (type == COM_TYPE_OMAP) {
2465 		/* disable before changing settings */
2466 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
2467 	}
2468 
2469 	rate = comspeed(rate, frequency, type);
2470 	if (rate != -1) {
2471 		if (type == COM_TYPE_AU1x00) {
2472 			/* no EFR on alchemy */
2473 			CSR_WRITE_2(regsp, COM_REG_DLBL, rate);
2474 		} else {
2475 			if ((type != COM_TYPE_16550_NOERS) &&
2476 			    (type != COM_TYPE_INGENIC)) {
2477 				CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
2478 				CSR_WRITE_1(regsp, COM_REG_EFR, 0);
2479 			}
2480 			CSR_WRITE_1(regsp, COM_REG_LCR, LCR_DLAB);
2481 			CSR_WRITE_1(regsp, COM_REG_DLBL, rate & 0xff);
2482 			CSR_WRITE_1(regsp, COM_REG_DLBH, rate >> 8);
2483 		}
2484 	}
2485 	CSR_WRITE_1(regsp, COM_REG_LCR, cflag2lcr(cflag));
2486 	CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2487 
2488 	if (type == COM_TYPE_INGENIC) {
2489 		CSR_WRITE_1(regsp, COM_REG_FIFO,
2490 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
2491 		    FIFO_TRIGGER_1 | FIFO_UART_ON);
2492 	} else {
2493 		CSR_WRITE_1(regsp, COM_REG_FIFO,
2494 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
2495 		    FIFO_TRIGGER_1);
2496 	}
2497 
2498 	if (type == COM_TYPE_OMAP) {
2499 		/* setup the fifos.  the FCR value is not used as long
2500 		   as SCR[6] and SCR[7] are 0, which they are at reset
2501 		   and we never touch the SCR register */
2502 		uint8_t rx_fifo_trig = 40;
2503 		uint8_t tx_fifo_trig = 60;
2504 		uint8_t rx_start = 8;
2505 		uint8_t rx_halt = 60;
2506 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
2507 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
2508 
2509 		/* enable access to TCR & TLR */
2510 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS | MCR_TCR_TLR);
2511 
2512 		/* write tcr and tlr values */
2513 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
2514 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
2515 
2516 		/* disable access to TCR & TLR */
2517 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2518 
2519 		/* enable again, but mode is based on speed */
2520 		if (rate > 230400) {
2521 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
2522 		} else {
2523 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
2524 		}
2525 	}
2526 
2527 	if (type == COM_TYPE_PXA2x0)
2528 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
2529 	else
2530 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
2531 
2532 	return (0);
2533 }
2534 
2535 int
2536 comcnattach1(struct com_regs *regsp, int rate, int frequency, int type,
2537     tcflag_t cflag)
2538 {
2539 	int res;
2540 
2541 	comcons_info.regs = *regsp;
2542 
2543 	res = cominit(&comcons_info.regs, rate, frequency, type, cflag);
2544 	if (res)
2545 		return (res);
2546 
2547 	cn_tab = &comcons;
2548 	cn_init_magic(&com_cnm_state);
2549 	cn_set_magic("\047\001"); /* default magic is BREAK */
2550 
2551 	comcons_info.frequency = frequency;
2552 	comcons_info.type = type;
2553 	comcons_info.rate = rate;
2554 	comcons_info.cflag = cflag;
2555 
2556 	return (0);
2557 }
2558 
2559 int
2560 comcnattach(bus_space_tag_t iot, bus_addr_t iobase, int rate, int frequency,
2561     int type, tcflag_t cflag)
2562 {
2563 	struct com_regs	regs;
2564 
2565 	/*XXX*/
2566 	bus_space_handle_t dummy_bsh;
2567 	memset(&dummy_bsh, 0, sizeof(dummy_bsh));
2568 
2569 	/*
2570 	 * dummy_bsh required because com_init_regs() wants it.  A
2571 	 * real bus_space_handle will be filled in by cominit() later.
2572 	 * XXXJRT Detangle this mess eventually, plz.
2573 	 */
2574 	com_init_regs(&regs, iot, dummy_bsh/*XXX*/, iobase);
2575 
2576 	return comcnattach1(&regs, rate, frequency, type, cflag);
2577 }
2578 
2579 static int
2580 comcnreattach(void)
2581 {
2582 	return comcnattach1(&comcons_info.regs, comcons_info.rate,
2583 	    comcons_info.frequency, comcons_info.type, comcons_info.cflag);
2584 }
2585 
2586 int
2587 comcngetc(dev_t dev)
2588 {
2589 
2590 	return (com_common_getc(dev, &comcons_info.regs));
2591 }
2592 
2593 /*
2594  * Console kernel output character routine.
2595  */
2596 void
2597 comcnputc(dev_t dev, int c)
2598 {
2599 
2600 	com_common_putc(dev, &comcons_info.regs, c, cold);
2601 }
2602 
2603 void
2604 comcnpollc(dev_t dev, int on)
2605 {
2606 
2607 	com_readaheadcount = 0;
2608 }
2609 
2610 #ifdef KGDB
2611 int
2612 com_kgdb_attach1(struct com_regs *regsp, int rate, int frequency, int type,
2613     tcflag_t cflag)
2614 {
2615 	int res;
2616 
2617 	if (bus_space_is_equal(regsp->cr_iot, comcons_info.regs.cr_iot) &&
2618 	    regsp->cr_iobase == comcons_info.regs.cr_iobase) {
2619 #if !defined(DDB)
2620 		return (EBUSY); /* cannot share with console */
2621 #else
2622 		comkgdbregs = *regsp;
2623 		comkgdbregs.cr_ioh = comcons_info.regs.cr_ioh;
2624 #endif
2625 	} else {
2626 		comkgdbregs = *regsp;
2627 		res = cominit(&comkgdbregs, rate, frequency, type, cflag);
2628 		if (res)
2629 			return (res);
2630 
2631 		/*
2632 		 * XXXfvdl this shouldn't be needed, but the cn_magic goo
2633 		 * expects this to be initialized
2634 		 */
2635 		cn_init_magic(&com_cnm_state);
2636 		cn_set_magic("\047\001");
2637 	}
2638 
2639 	kgdb_attach(com_kgdb_getc, com_kgdb_putc, NULL);
2640 	kgdb_dev = 123; /* unneeded, only to satisfy some tests */
2641 
2642 	return (0);
2643 }
2644 
2645 int
2646 com_kgdb_attach(bus_space_tag_t iot, bus_addr_t iobase, int rate,
2647     int frequency, int type, tcflag_t cflag)
2648 {
2649 	struct com_regs regs;
2650 
2651 	com_init_regs(&regs, iot, (bus_space_handle_t)0/*XXX*/, iobase);
2652 
2653 	return com_kgdb_attach1(&regs, rate, frequency, type, cflag);
2654 }
2655 
2656 /* ARGSUSED */
2657 int
2658 com_kgdb_getc(void *arg)
2659 {
2660 
2661 	return (com_common_getc(NODEV, &comkgdbregs));
2662 }
2663 
2664 /* ARGSUSED */
2665 void
2666 com_kgdb_putc(void *arg, int c)
2667 {
2668 
2669 	com_common_putc(NODEV, &comkgdbregs, c, 0);
2670 }
2671 #endif /* KGDB */
2672 
2673 /* helper function to identify the com ports used by
2674  console or KGDB (and not yet autoconf attached) */
2675 int
2676 com_is_console(bus_space_tag_t iot, bus_addr_t iobase, bus_space_handle_t *ioh)
2677 {
2678 	bus_space_handle_t help;
2679 
2680 	if (!comconsattached &&
2681 	    bus_space_is_equal(iot, comcons_info.regs.cr_iot) &&
2682 	    iobase == comcons_info.regs.cr_iobase)
2683 		help = comcons_info.regs.cr_ioh;
2684 #ifdef KGDB
2685 	else if (!com_kgdb_attached &&
2686 	    bus_space_is_equal(iot, comkgdbregs.cr_iot) &&
2687 	    iobase == comkgdbregs.cr_iobase)
2688 		help = comkgdbregs.cr_ioh;
2689 #endif
2690 	else
2691 		return (0);
2692 
2693 	if (ioh)
2694 		*ioh = help;
2695 	return (1);
2696 }
2697 
2698 /*
2699  * this routine exists to serve as a shutdown hook for systems that
2700  * have firmware which doesn't interact properly with a com device in
2701  * FIFO mode.
2702  */
2703 bool
2704 com_cleanup(device_t self, int how)
2705 {
2706 	struct com_softc *sc = device_private(self);
2707 
2708 	if (ISSET(sc->sc_hwflags, COM_HW_FIFO))
2709 		CSR_WRITE_1(&sc->sc_regs, COM_REG_FIFO, 0);
2710 
2711 	return true;
2712 }
2713 
2714 bool
2715 com_suspend(device_t self, const pmf_qual_t *qual)
2716 {
2717 	struct com_softc *sc = device_private(self);
2718 
2719 #if 0
2720 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE) && cn_tab == &comcons)
2721 		cn_tab = &comcons_suspend;
2722 #endif
2723 
2724 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, 0);
2725 	(void)CSR_READ_1(&sc->sc_regs, COM_REG_IIR);
2726 
2727 	return true;
2728 }
2729 
2730 bool
2731 com_resume(device_t self, const pmf_qual_t *qual)
2732 {
2733 	struct com_softc *sc = device_private(self);
2734 
2735 	mutex_spin_enter(&sc->sc_lock);
2736 	com_loadchannelregs(sc);
2737 	mutex_spin_exit(&sc->sc_lock);
2738 
2739 	return true;
2740 }
2741