xref: /netbsd-src/sys/dev/ic/com.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f)
1 /* $NetBSD: com.c,v 1.359 2020/05/26 13:24:52 martin 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 1.359 2020/05/26 13:24:52 martin 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, 1);
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 	u_int8_t lcr;
432 	const char *fifo_msg = NULL;
433 	prop_dictionary_t	dict;
434 	bool is_console = true;
435 	bool force_console = false;
436 
437 	aprint_naive("\n");
438 
439 	dict = device_properties(sc->sc_dev);
440 	prop_dictionary_get_bool(dict, "is_console", &is_console);
441 	prop_dictionary_get_bool(dict, "force_console", &force_console);
442 	callout_init(&sc->sc_diag_callout, 0);
443 	callout_init(&sc->sc_poll_callout, 0);
444 	callout_setfunc(&sc->sc_poll_callout, com_intr_poll, sc);
445 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_HIGH);
446 
447 #if defined(COM_16650)
448 	sc->sc_type = COM_TYPE_16650;
449 #elif defined(COM_16750)
450 	sc->sc_type = COM_TYPE_16750;
451 #elif defined(COM_HAYESP)
452 	sc->sc_type = COM_TYPE_HAYESP;
453 #elif defined(COM_PXA2X0)
454 	sc->sc_type = COM_TYPE_PXA2x0;
455 #endif
456 
457 	/* Disable interrupts before configuring the device. */
458 	if (sc->sc_type == COM_TYPE_PXA2x0)
459 		sc->sc_ier = IER_EUART;
460 	else
461 		sc->sc_ier = 0;
462 
463 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
464 
465 	if ((bus_space_is_equal(regsp->cr_iot, comcons_info.regs.cr_iot) &&
466 	    regsp->cr_iobase == comcons_info.regs.cr_iobase) || force_console) {
467 		comconsattached = 1;
468 
469 		if (force_console)
470 			memcpy(regsp, &comcons_info.regs, sizeof(*regsp));
471 
472 		if (cn_tab == NULL && comcnreattach() != 0) {
473 			printf("can't re-init serial console @%lx\n",
474 			    (u_long)comcons_info.regs.cr_iobase);
475 		}
476 
477 		switch (sc->sc_type) {
478 		case COM_TYPE_16750:
479 		case COM_TYPE_DW_APB:
480 			/* Use in comintr(). */
481  			sc->sc_lcr = cflag2lcr(comcons_info.cflag);
482 			break;
483 		}
484 
485 		/* Make sure the console is always "hardwired". */
486 		delay(10000);			/* wait for output to finish */
487 		if (is_console) {
488 			SET(sc->sc_hwflags, COM_HW_CONSOLE);
489 		}
490 
491 		SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
492 	}
493 
494 	/* Probe for FIFO */
495 	switch (sc->sc_type) {
496 	case COM_TYPE_HAYESP:
497 		goto fifodone;
498 
499 	case COM_TYPE_AU1x00:
500 		sc->sc_fifolen = 16;
501 		fifo_msg = "Au1X00 UART, working fifo";
502 		SET(sc->sc_hwflags, COM_HW_FIFO);
503 		goto fifodelay;
504 
505 	case COM_TYPE_16550_NOERS:
506 		sc->sc_fifolen = 16;
507 		fifo_msg = "ns16650, no ERS, working fifo";
508 		SET(sc->sc_hwflags, COM_HW_FIFO);
509 		goto fifodelay;
510 
511 	case COM_TYPE_OMAP:
512 		sc->sc_fifolen = 64;
513 		fifo_msg = "OMAP UART, working fifo";
514 		SET(sc->sc_hwflags, COM_HW_FIFO);
515 		goto fifodelay;
516 
517 	case COM_TYPE_INGENIC:
518 		sc->sc_fifolen = 16;
519 		fifo_msg = "Ingenic UART, working fifo";
520 		SET(sc->sc_hwflags, COM_HW_FIFO);
521 		SET(sc->sc_hwflags, COM_HW_NOIEN);
522 		goto fifodelay;
523 
524 	case COM_TYPE_TEGRA:
525 		sc->sc_fifolen = 8;
526 		fifo_msg = "Tegra UART, working fifo";
527 		SET(sc->sc_hwflags, COM_HW_FIFO);
528 		CSR_WRITE_1(regsp, COM_REG_FIFO,
529 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
530 		goto fifodelay;
531 
532 	case COM_TYPE_BCMAUXUART:
533 		sc->sc_fifolen = 1;
534 		fifo_msg = "BCM AUX UART, working fifo";
535 		SET(sc->sc_hwflags, COM_HW_FIFO);
536 		CSR_WRITE_1(regsp, COM_REG_FIFO,
537 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
538 		goto fifodelay;
539 	}
540 
541 	sc->sc_fifolen = 1;
542 	/* look for a NS 16550AF UART with FIFOs */
543 	if (sc->sc_type == COM_TYPE_INGENIC) {
544 		CSR_WRITE_1(regsp, COM_REG_FIFO,
545 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
546 		    FIFO_TRIGGER_14 | FIFO_UART_ON);
547 	} else
548 		CSR_WRITE_1(regsp, COM_REG_FIFO,
549 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_14);
550 	delay(100);
551 	if (ISSET(CSR_READ_1(regsp, COM_REG_IIR), IIR_FIFO_MASK)
552 	    == IIR_FIFO_MASK)
553 		if (ISSET(CSR_READ_1(regsp, COM_REG_FIFO), FIFO_TRIGGER_14)
554 		    == FIFO_TRIGGER_14) {
555 			SET(sc->sc_hwflags, COM_HW_FIFO);
556 
557 			fifo_msg = "ns16550a, working fifo";
558 
559 			/*
560 			 * IIR changes into the EFR if LCR is set to LCR_EERS
561 			 * on 16650s. We also know IIR != 0 at this point.
562 			 * Write 0 into the EFR, and read it. If the result
563 			 * is 0, we have a 16650.
564 			 *
565 			 * Older 16650s were broken; the test to detect them
566 			 * is taken from the Linux driver. Apparently
567 			 * setting DLAB enable gives access to the EFR on
568 			 * these chips.
569 			 */
570 			if (sc->sc_type == COM_TYPE_16650) {
571 				lcr = CSR_READ_1(regsp, COM_REG_LCR);
572 				CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
573 				CSR_WRITE_1(regsp, COM_REG_EFR, 0);
574 				if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
575 					CSR_WRITE_1(regsp, COM_REG_LCR,
576 					    lcr | LCR_DLAB);
577 					if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
578 						CLR(sc->sc_hwflags, COM_HW_FIFO);
579 						sc->sc_fifolen = 0;
580 					} else {
581 						SET(sc->sc_hwflags, COM_HW_FLOW);
582 						sc->sc_fifolen = 32;
583 					}
584 				} else
585 					sc->sc_fifolen = 16;
586 
587 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
588 				if (sc->sc_fifolen == 0)
589 					fifo_msg = "st16650, broken fifo";
590 				else if (sc->sc_fifolen == 32)
591 					fifo_msg = "st16650a, working fifo";
592 				else
593 					fifo_msg = "ns16550a, working fifo";
594 			}
595 
596 			/*
597 			 * TL16C750 can enable 64byte FIFO, only when DLAB
598 			 * is 1.  However, some 16750 may always enable.  For
599 			 * example, restrictions according to DLAB in a data
600 			 * sheet for SC16C750 were not described.
601 			 * Please enable 'options COM_16650', supposing you
602 			 * use SC16C750.  Probably 32 bytes of FIFO and HW FLOW
603 			 * should become effective.
604 			 */
605 			if (sc->sc_type == COM_TYPE_16750) {
606 				uint8_t iir1, iir2;
607 				uint8_t fcr = FIFO_ENABLE | FIFO_TRIGGER_14;
608 
609 				lcr = CSR_READ_1(regsp, COM_REG_LCR);
610 				CSR_WRITE_1(regsp, COM_REG_LCR,
611 				    lcr & ~LCR_DLAB);
612 				CSR_WRITE_1(regsp, COM_REG_FIFO,
613 				    fcr | FIFO_64B_ENABLE);
614 				iir1 = CSR_READ_1(regsp, COM_REG_IIR);
615 				CSR_WRITE_1(regsp, COM_REG_FIFO, fcr);
616 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr | LCR_DLAB);
617 				CSR_WRITE_1(regsp, COM_REG_FIFO,
618 				    fcr | FIFO_64B_ENABLE);
619 				iir2 = CSR_READ_1(regsp, COM_REG_IIR);
620 
621 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
622 
623 				if (!ISSET(iir1, IIR_64B_FIFO) &&
624 				    ISSET(iir2, IIR_64B_FIFO)) {
625 					/* It is TL16C750. */
626 					sc->sc_fifolen = 64;
627 					SET(sc->sc_hwflags, COM_HW_AFE);
628 				} else
629 					CSR_WRITE_1(regsp, COM_REG_FIFO, fcr);
630 
631 				if (sc->sc_fifolen == 64)
632 					fifo_msg = "tl16c750, working fifo";
633 				else
634 					fifo_msg = "ns16750, working fifo";
635 			}
636 		} else
637 			fifo_msg = "ns16550, broken fifo";
638 	else
639 		fifo_msg = "ns8250 or ns16450, no fifo";
640 	CSR_WRITE_1(regsp, COM_REG_FIFO, 0);
641 
642 fifodelay:
643 	/*
644 	 * Some chips will clear down both Tx and Rx FIFOs when zero is
645 	 * written to com_fifo. If this chip is the console, writing zero
646 	 * results in some of the chip/FIFO description being lost, so delay
647 	 * printing it until now.
648 	 */
649 	delay(10);
650 	aprint_normal(": %s\n", fifo_msg);
651 	if (ISSET(sc->sc_hwflags, COM_HW_TXFIFO_DISABLE)) {
652 		sc->sc_fifolen = 1;
653 		aprint_normal_dev(sc->sc_dev, "txfifo disabled\n");
654 	}
655 
656 fifodone:
657 
658 	tp = tty_alloc();
659 	tp->t_oproc = comstart;
660 	tp->t_param = comparam;
661 	tp->t_hwiflow = comhwiflow;
662 	tp->t_softc = sc;
663 
664 	sc->sc_tty = tp;
665 	sc->sc_rbuf = malloc(com_rbuf_size << 1, M_DEVBUF, M_WAITOK);
666 	sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
667 	sc->sc_rbavail = com_rbuf_size;
668 	sc->sc_ebuf = sc->sc_rbuf + (com_rbuf_size << 1);
669 
670 	tty_attach(tp);
671 
672 	if (!ISSET(sc->sc_hwflags, COM_HW_NOIEN))
673 		SET(sc->sc_mcr, MCR_IENABLE);
674 
675 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
676 		int maj;
677 
678 		/* locate the major number */
679 		maj = cdevsw_lookup_major(&com_cdevsw);
680 
681 		tp->t_dev = cn_tab->cn_dev = makedev(maj,
682 						     device_unit(sc->sc_dev));
683 
684 		aprint_normal_dev(sc->sc_dev, "console\n");
685 	}
686 
687 #ifdef KGDB
688 	/*
689 	 * Allow kgdb to "take over" this port.  If this is
690 	 * not the console and is the kgdb device, it has
691 	 * exclusive use.  If it's the console _and_ the
692 	 * kgdb device, it doesn't.
693 	 */
694 	if (bus_space_is_equal(regsp->cr_iot, comkgdbregs.cr_iot) &&
695 	    regsp->cr_iobase == comkgdbregs.cr_iobase) {
696 		if (!ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
697 			com_kgdb_attached = 1;
698 
699 			SET(sc->sc_hwflags, COM_HW_KGDB);
700 		}
701 		aprint_normal_dev(sc->sc_dev, "kgdb\n");
702 	}
703 #endif
704 
705 	sc->sc_si = softint_establish(SOFTINT_SERIAL, comsoft, sc);
706 
707 #ifdef RND_COM
708 	rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
709 			  RND_TYPE_TTY, RND_FLAG_DEFAULT);
710 #endif
711 
712 	/* if there are no enable/disable functions, assume the device
713 	   is always enabled */
714 	if (!sc->enable)
715 		sc->enabled = 1;
716 
717 	com_config(sc);
718 
719 	SET(sc->sc_hwflags, COM_HW_DEV_OK);
720 
721 	if (ISSET(sc->sc_hwflags, COM_HW_POLL))
722 		callout_schedule(&sc->sc_poll_callout, 1);
723 }
724 
725 void
726 com_config(struct com_softc *sc)
727 {
728 	struct com_regs *regsp = &sc->sc_regs;
729 
730 	/* Disable interrupts before configuring the device. */
731 	if (sc->sc_type == COM_TYPE_PXA2x0)
732 		sc->sc_ier = IER_EUART;
733 	else
734 		sc->sc_ier = 0;
735 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
736 	(void) CSR_READ_1(regsp, COM_REG_IIR);
737 
738 	/* Look for a Hayes ESP board. */
739 	if (sc->sc_type == COM_TYPE_HAYESP) {
740 
741 		/* Set 16550 compatibility mode */
742 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
743 				  HAYESP_SETMODE);
744 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
745 				  HAYESP_MODE_FIFO|HAYESP_MODE_RTS|
746 				  HAYESP_MODE_SCALE);
747 
748 		/* Set RTS/CTS flow control */
749 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
750 				  HAYESP_SETFLOWTYPE);
751 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
752 				  HAYESP_FLOW_RTS);
753 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
754 				  HAYESP_FLOW_CTS);
755 
756 		/* Set flow control levels */
757 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
758 				  HAYESP_SETRXFLOW);
759 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
760 				  HAYESP_HIBYTE(HAYESP_RXHIWMARK));
761 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
762 				  HAYESP_LOBYTE(HAYESP_RXHIWMARK));
763 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
764 				  HAYESP_HIBYTE(HAYESP_RXLOWMARK));
765 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
766 				  HAYESP_LOBYTE(HAYESP_RXLOWMARK));
767 	}
768 
769 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE|COM_HW_KGDB))
770 		com_enable_debugport(sc);
771 }
772 
773 #if 0
774 static int
775 comcngetc_detached(dev_t dev)
776 {
777 	return 0;
778 }
779 
780 static void
781 comcnputc_detached(dev_t dev, int c)
782 {
783 }
784 #endif
785 
786 int
787 com_detach(device_t self, int flags)
788 {
789 	struct com_softc *sc = device_private(self);
790 	int maj, mn;
791 
792 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
793 		return EBUSY;
794 
795 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE) &&
796 	    (flags & DETACH_SHUTDOWN) != 0)
797 		return EBUSY;
798 
799 	if (sc->disable != NULL && sc->enabled != 0) {
800 		(*sc->disable)(sc);
801 		sc->enabled = 0;
802 	}
803 
804 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
805 		comconsattached = 0;
806 		cn_tab = NULL;
807 	}
808 
809 	/* locate the major number */
810 	maj = cdevsw_lookup_major(&com_cdevsw);
811 
812 	/* Nuke the vnodes for any open instances. */
813 	mn = device_unit(self);
814 	vdevgone(maj, mn, mn, VCHR);
815 
816 	mn |= COMDIALOUT_MASK;
817 	vdevgone(maj, mn, mn, VCHR);
818 
819 	if (sc->sc_rbuf == NULL) {
820 		/*
821 		 * Ring buffer allocation failed in the com_attach_subr,
822 		 * only the tty is allocated, and nothing else.
823 		 */
824 		tty_free(sc->sc_tty);
825 		return 0;
826 	}
827 
828 	/* Free the receive buffer. */
829 	free(sc->sc_rbuf, M_DEVBUF);
830 
831 	/* Detach and free the tty. */
832 	tty_detach(sc->sc_tty);
833 	tty_free(sc->sc_tty);
834 
835 	/* Unhook the soft interrupt handler. */
836 	softint_disestablish(sc->sc_si);
837 
838 #ifdef RND_COM
839 	/* Unhook the entropy source. */
840 	rnd_detach_source(&sc->rnd_source);
841 #endif
842 	callout_destroy(&sc->sc_diag_callout);
843 
844 	/* Destroy the lock. */
845 	mutex_destroy(&sc->sc_lock);
846 
847 	return (0);
848 }
849 
850 void
851 com_shutdown(struct com_softc *sc)
852 {
853 	struct tty *tp = sc->sc_tty;
854 
855 	mutex_spin_enter(&sc->sc_lock);
856 
857 	/* If we were asserting flow control, then deassert it. */
858 	SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
859 	com_hwiflow(sc);
860 
861 	/* Clear any break condition set with TIOCSBRK. */
862 	com_break(sc, 0);
863 
864 	/*
865 	 * Hang up if necessary.  Wait a bit, so the other side has time to
866 	 * notice even if we immediately open the port again.
867 	 * Avoid tsleeping above splhigh().
868 	 */
869 	if (ISSET(tp->t_cflag, HUPCL)) {
870 		com_modem(sc, 0);
871 		mutex_spin_exit(&sc->sc_lock);
872 		/* XXX will only timeout */
873 		(void) kpause(ttclos, false, hz, NULL);
874 		mutex_spin_enter(&sc->sc_lock);
875 	}
876 
877 	/* Turn off interrupts. */
878 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
879 		sc->sc_ier = IER_ERLS; /* interrupt on line break */
880 		if ((sc->sc_type == COM_TYPE_PXA2x0) ||
881 		    (sc->sc_type == COM_TYPE_INGENIC) ||
882 		    (sc->sc_type == COM_TYPE_TEGRA))
883 			sc->sc_ier |= IER_ERXTOUT;
884 	} else
885 		sc->sc_ier = 0;
886 
887 	if (sc->sc_type == COM_TYPE_PXA2x0)
888 		sc->sc_ier |= IER_EUART;
889 
890 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
891 
892 	mutex_spin_exit(&sc->sc_lock);
893 
894 	if (sc->disable) {
895 #ifdef DIAGNOSTIC
896 		if (!sc->enabled)
897 			panic("com_shutdown: not enabled?");
898 #endif
899 		(*sc->disable)(sc);
900 		sc->enabled = 0;
901 	}
902 }
903 
904 int
905 comopen(dev_t dev, int flag, int mode, struct lwp *l)
906 {
907 	struct com_softc *sc;
908 	struct tty *tp;
909 	int s;
910 	int error;
911 
912 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
913 	if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK) ||
914 		sc->sc_rbuf == NULL)
915 		return (ENXIO);
916 
917 	if (!device_is_active(sc->sc_dev))
918 		return (ENXIO);
919 
920 #ifdef KGDB
921 	/*
922 	 * If this is the kgdb port, no other use is permitted.
923 	 */
924 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
925 		return (EBUSY);
926 #endif
927 
928 	tp = sc->sc_tty;
929 
930 	/*
931 	 * If the device is exclusively for kernel use, deny userland
932 	 * open.
933 	 */
934 	if (ISSET(tp->t_state, TS_KERN_ONLY))
935 		return (EBUSY);
936 
937 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
938 		return (EBUSY);
939 
940 	s = spltty();
941 
942 	/*
943 	 * Do the following iff this is a first open.
944 	 */
945 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
946 		struct termios t;
947 
948 		tp->t_dev = dev;
949 
950 		if (sc->enable) {
951 			if ((*sc->enable)(sc)) {
952 				splx(s);
953 				aprint_error_dev(sc->sc_dev,
954 				    "device enable failed\n");
955 				return (EIO);
956 			}
957 			mutex_spin_enter(&sc->sc_lock);
958 			sc->enabled = 1;
959 			com_config(sc);
960 		} else {
961 			mutex_spin_enter(&sc->sc_lock);
962 		}
963 
964 		/* Turn on interrupts. */
965 		sc->sc_ier = IER_ERXRDY | IER_ERLS;
966 		if (!ISSET(tp->t_cflag, CLOCAL))
967 			sc->sc_ier |= IER_EMSC;
968 
969 		if (sc->sc_type == COM_TYPE_PXA2x0)
970 			sc->sc_ier |= IER_EUART | IER_ERXTOUT;
971 		else if (sc->sc_type == COM_TYPE_INGENIC ||
972 			 sc->sc_type == COM_TYPE_TEGRA)
973 			sc->sc_ier |= IER_ERXTOUT;
974 		CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
975 
976 		/* Fetch the current modem control status, needed later. */
977 		sc->sc_msr = CSR_READ_1(&sc->sc_regs, COM_REG_MSR);
978 
979 		/* Clear PPS capture state on first open. */
980 		mutex_spin_enter(&timecounter_lock);
981 		memset(&sc->sc_pps_state, 0, sizeof(sc->sc_pps_state));
982 		sc->sc_pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
983 		pps_init(&sc->sc_pps_state);
984 		mutex_spin_exit(&timecounter_lock);
985 
986 		mutex_spin_exit(&sc->sc_lock);
987 
988 		/*
989 		 * Initialize the termios status to the defaults.  Add in the
990 		 * sticky bits from TIOCSFLAGS.
991 		 */
992 		if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
993 			t.c_ospeed = comcons_info.rate;
994 			t.c_cflag = comcons_info.cflag;
995 		} else {
996 			t.c_ospeed = TTYDEF_SPEED;
997 			t.c_cflag = TTYDEF_CFLAG;
998 		}
999 		t.c_ispeed = t.c_ospeed;
1000 		if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
1001 			SET(t.c_cflag, CLOCAL);
1002 		if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
1003 			SET(t.c_cflag, CRTSCTS);
1004 		if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
1005 			SET(t.c_cflag, MDMBUF);
1006 		/* Make sure comparam() will do something. */
1007 		tp->t_ospeed = 0;
1008 		(void) comparam(tp, &t);
1009 		tp->t_iflag = TTYDEF_IFLAG;
1010 		tp->t_oflag = TTYDEF_OFLAG;
1011 		tp->t_lflag = TTYDEF_LFLAG;
1012 		ttychars(tp);
1013 		ttsetwater(tp);
1014 
1015 		mutex_spin_enter(&sc->sc_lock);
1016 
1017 		/*
1018 		 * Turn on DTR.  We must always do this, even if carrier is not
1019 		 * present, because otherwise we'd have to use TIOCSDTR
1020 		 * immediately after setting CLOCAL, which applications do not
1021 		 * expect.  We always assert DTR while the device is open
1022 		 * unless explicitly requested to deassert it.
1023 		 */
1024 		com_modem(sc, 1);
1025 
1026 		/* Clear the input ring, and unblock. */
1027 		sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
1028 		sc->sc_rbavail = com_rbuf_size;
1029 		com_iflush(sc);
1030 		CLR(sc->sc_rx_flags, RX_ANY_BLOCK);
1031 		com_hwiflow(sc);
1032 
1033 #ifdef COM_DEBUG
1034 		if (com_debug)
1035 			comstatus(sc, "comopen  ");
1036 #endif
1037 
1038 		mutex_spin_exit(&sc->sc_lock);
1039 	}
1040 
1041 	splx(s);
1042 
1043 	error = ttyopen(tp, COMDIALOUT(dev), ISSET(flag, O_NONBLOCK));
1044 	if (error)
1045 		goto bad;
1046 
1047 	error = (*tp->t_linesw->l_open)(dev, tp);
1048 	if (error)
1049 		goto bad;
1050 
1051 	return (0);
1052 
1053 bad:
1054 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
1055 		/*
1056 		 * We failed to open the device, and nobody else had it opened.
1057 		 * Clean up the state as appropriate.
1058 		 */
1059 		com_shutdown(sc);
1060 	}
1061 
1062 	return (error);
1063 }
1064 
1065 int
1066 comclose(dev_t dev, int flag, int mode, struct lwp *l)
1067 {
1068 	struct com_softc *sc =
1069 	    device_lookup_private(&com_cd, COMUNIT(dev));
1070 	struct tty *tp = sc->sc_tty;
1071 
1072 	/* XXX This is for cons.c. */
1073 	if (!ISSET(tp->t_state, TS_ISOPEN))
1074 		return (0);
1075 	/*
1076 	 * If the device is exclusively for kernel use, deny userland
1077 	 * close.
1078 	 */
1079 	if (ISSET(tp->t_state, TS_KERN_ONLY))
1080 		return (0);
1081 
1082 	(*tp->t_linesw->l_close)(tp, flag);
1083 	ttyclose(tp);
1084 
1085 	if (COM_ISALIVE(sc) == 0)
1086 		return (0);
1087 
1088 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
1089 		/*
1090 		 * Although we got a last close, the device may still be in
1091 		 * use; e.g. if this was the dialout node, and there are still
1092 		 * processes waiting for carrier on the non-dialout node.
1093 		 */
1094 		com_shutdown(sc);
1095 	}
1096 
1097 	return (0);
1098 }
1099 
1100 int
1101 comread(dev_t dev, struct uio *uio, int flag)
1102 {
1103 	struct com_softc *sc =
1104 	    device_lookup_private(&com_cd, COMUNIT(dev));
1105 	struct tty *tp = sc->sc_tty;
1106 
1107 	if (COM_ISALIVE(sc) == 0)
1108 		return (EIO);
1109 
1110 	return ((*tp->t_linesw->l_read)(tp, uio, flag));
1111 }
1112 
1113 int
1114 comwrite(dev_t dev, struct uio *uio, int flag)
1115 {
1116 	struct com_softc *sc =
1117 	    device_lookup_private(&com_cd, COMUNIT(dev));
1118 	struct tty *tp = sc->sc_tty;
1119 
1120 	if (COM_ISALIVE(sc) == 0)
1121 		return (EIO);
1122 
1123 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
1124 }
1125 
1126 int
1127 compoll(dev_t dev, int events, struct lwp *l)
1128 {
1129 	struct com_softc *sc =
1130 	    device_lookup_private(&com_cd, COMUNIT(dev));
1131 	struct tty *tp = sc->sc_tty;
1132 
1133 	if (COM_ISALIVE(sc) == 0)
1134 		return (POLLHUP);
1135 
1136 	return ((*tp->t_linesw->l_poll)(tp, events, l));
1137 }
1138 
1139 struct tty *
1140 comtty(dev_t dev)
1141 {
1142 	struct com_softc *sc =
1143 	    device_lookup_private(&com_cd, COMUNIT(dev));
1144 	struct tty *tp = sc->sc_tty;
1145 
1146 	return (tp);
1147 }
1148 
1149 int
1150 comioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
1151 {
1152 	struct com_softc *sc;
1153 	struct tty *tp;
1154 	int error;
1155 
1156 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
1157 	if (sc == NULL)
1158 		return ENXIO;
1159 	if (COM_ISALIVE(sc) == 0)
1160 		return (EIO);
1161 
1162 	tp = sc->sc_tty;
1163 
1164 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
1165 	if (error != EPASSTHROUGH)
1166 		return (error);
1167 
1168 	error = ttioctl(tp, cmd, data, flag, l);
1169 	if (error != EPASSTHROUGH)
1170 		return (error);
1171 
1172 	error = 0;
1173 	switch (cmd) {
1174 	case TIOCSFLAGS:
1175 		error = kauth_authorize_device_tty(l->l_cred,
1176 		    KAUTH_DEVICE_TTY_PRIVSET, tp);
1177 		break;
1178 	default:
1179 		/* nothing */
1180 		break;
1181 	}
1182 	if (error) {
1183 		return error;
1184 	}
1185 
1186 	mutex_spin_enter(&sc->sc_lock);
1187 
1188 	switch (cmd) {
1189 	case TIOCSBRK:
1190 		com_break(sc, 1);
1191 		break;
1192 
1193 	case TIOCCBRK:
1194 		com_break(sc, 0);
1195 		break;
1196 
1197 	case TIOCSDTR:
1198 		com_modem(sc, 1);
1199 		break;
1200 
1201 	case TIOCCDTR:
1202 		com_modem(sc, 0);
1203 		break;
1204 
1205 	case TIOCGFLAGS:
1206 		*(int *)data = sc->sc_swflags;
1207 		break;
1208 
1209 	case TIOCSFLAGS:
1210 		sc->sc_swflags = *(int *)data;
1211 		break;
1212 
1213 	case TIOCMSET:
1214 	case TIOCMBIS:
1215 	case TIOCMBIC:
1216 		tiocm_to_com(sc, cmd, *(int *)data);
1217 		break;
1218 
1219 	case TIOCMGET:
1220 		*(int *)data = com_to_tiocm(sc);
1221 		break;
1222 
1223 	case PPS_IOC_CREATE:
1224 	case PPS_IOC_DESTROY:
1225 	case PPS_IOC_GETPARAMS:
1226 	case PPS_IOC_SETPARAMS:
1227 	case PPS_IOC_GETCAP:
1228 	case PPS_IOC_FETCH:
1229 #ifdef PPS_SYNC
1230 	case PPS_IOC_KCBIND:
1231 #endif
1232 		mutex_spin_enter(&timecounter_lock);
1233 		error = pps_ioctl(cmd, data, &sc->sc_pps_state);
1234 		mutex_spin_exit(&timecounter_lock);
1235 		break;
1236 
1237 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
1238 		mutex_spin_enter(&timecounter_lock);
1239 #ifndef PPS_TRAILING_EDGE
1240 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1241 		    &sc->sc_pps_state.ppsinfo.assert_timestamp);
1242 #else
1243 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1244 		    &sc->sc_pps_state.ppsinfo.clear_timestamp);
1245 #endif
1246 		mutex_spin_exit(&timecounter_lock);
1247 		break;
1248 
1249 	default:
1250 		error = EPASSTHROUGH;
1251 		break;
1252 	}
1253 
1254 	mutex_spin_exit(&sc->sc_lock);
1255 
1256 #ifdef COM_DEBUG
1257 	if (com_debug)
1258 		comstatus(sc, "comioctl ");
1259 #endif
1260 
1261 	return (error);
1262 }
1263 
1264 integrate void
1265 com_schedrx(struct com_softc *sc)
1266 {
1267 
1268 	sc->sc_rx_ready = 1;
1269 
1270 	/* Wake up the poller. */
1271 	softint_schedule(sc->sc_si);
1272 }
1273 
1274 void
1275 com_break(struct com_softc *sc, int onoff)
1276 {
1277 
1278 	if (onoff)
1279 		SET(sc->sc_lcr, LCR_SBREAK);
1280 	else
1281 		CLR(sc->sc_lcr, LCR_SBREAK);
1282 
1283 	if (!sc->sc_heldchange) {
1284 		if (sc->sc_tx_busy) {
1285 			sc->sc_heldtbc = sc->sc_tbc;
1286 			sc->sc_tbc = 0;
1287 			sc->sc_heldchange = 1;
1288 		} else
1289 			com_loadchannelregs(sc);
1290 	}
1291 }
1292 
1293 void
1294 com_modem(struct com_softc *sc, int onoff)
1295 {
1296 
1297 	if (sc->sc_mcr_dtr == 0)
1298 		return;
1299 
1300 	if (onoff)
1301 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1302 	else
1303 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1304 
1305 	if (!sc->sc_heldchange) {
1306 		if (sc->sc_tx_busy) {
1307 			sc->sc_heldtbc = sc->sc_tbc;
1308 			sc->sc_tbc = 0;
1309 			sc->sc_heldchange = 1;
1310 		} else
1311 			com_loadchannelregs(sc);
1312 	}
1313 }
1314 
1315 void
1316 tiocm_to_com(struct com_softc *sc, u_long how, int ttybits)
1317 {
1318 	u_char combits;
1319 
1320 	combits = 0;
1321 	if (ISSET(ttybits, TIOCM_DTR))
1322 		SET(combits, MCR_DTR);
1323 	if (ISSET(ttybits, TIOCM_RTS))
1324 		SET(combits, MCR_RTS);
1325 
1326 	switch (how) {
1327 	case TIOCMBIC:
1328 		CLR(sc->sc_mcr, combits);
1329 		break;
1330 
1331 	case TIOCMBIS:
1332 		SET(sc->sc_mcr, combits);
1333 		break;
1334 
1335 	case TIOCMSET:
1336 		CLR(sc->sc_mcr, MCR_DTR | MCR_RTS);
1337 		SET(sc->sc_mcr, combits);
1338 		break;
1339 	}
1340 
1341 	if (!sc->sc_heldchange) {
1342 		if (sc->sc_tx_busy) {
1343 			sc->sc_heldtbc = sc->sc_tbc;
1344 			sc->sc_tbc = 0;
1345 			sc->sc_heldchange = 1;
1346 		} else
1347 			com_loadchannelregs(sc);
1348 	}
1349 }
1350 
1351 int
1352 com_to_tiocm(struct com_softc *sc)
1353 {
1354 	u_char combits;
1355 	int ttybits = 0;
1356 
1357 	combits = sc->sc_mcr;
1358 	if (ISSET(combits, MCR_DTR))
1359 		SET(ttybits, TIOCM_DTR);
1360 	if (ISSET(combits, MCR_RTS))
1361 		SET(ttybits, TIOCM_RTS);
1362 
1363 	combits = sc->sc_msr;
1364 	if (sc->sc_type == COM_TYPE_INGENIC) {
1365 		SET(ttybits, TIOCM_CD);
1366 	} else {
1367 		if (ISSET(combits, MSR_DCD))
1368 			SET(ttybits, TIOCM_CD);
1369 	}
1370 	if (ISSET(combits, MSR_CTS))
1371 		SET(ttybits, TIOCM_CTS);
1372 	if (ISSET(combits, MSR_DSR))
1373 		SET(ttybits, TIOCM_DSR);
1374 	if (ISSET(combits, MSR_RI | MSR_TERI))
1375 		SET(ttybits, TIOCM_RI);
1376 
1377 	if (ISSET(sc->sc_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS | IER_EMSC))
1378 		SET(ttybits, TIOCM_LE);
1379 
1380 	return (ttybits);
1381 }
1382 
1383 static u_char
1384 cflag2lcr(tcflag_t cflag)
1385 {
1386 	u_char lcr = 0;
1387 
1388 	switch (ISSET(cflag, CSIZE)) {
1389 	case CS5:
1390 		SET(lcr, LCR_5BITS);
1391 		break;
1392 	case CS6:
1393 		SET(lcr, LCR_6BITS);
1394 		break;
1395 	case CS7:
1396 		SET(lcr, LCR_7BITS);
1397 		break;
1398 	case CS8:
1399 		SET(lcr, LCR_8BITS);
1400 		break;
1401 	}
1402 	if (ISSET(cflag, PARENB)) {
1403 		SET(lcr, LCR_PENAB);
1404 		if (!ISSET(cflag, PARODD))
1405 			SET(lcr, LCR_PEVEN);
1406 	}
1407 	if (ISSET(cflag, CSTOPB))
1408 		SET(lcr, LCR_STOPB);
1409 
1410 	return (lcr);
1411 }
1412 
1413 int
1414 comparam(struct tty *tp, struct termios *t)
1415 {
1416 	struct com_softc *sc =
1417 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1418 	int ospeed;
1419 	u_char lcr;
1420 
1421 	if (COM_ISALIVE(sc) == 0)
1422 		return (EIO);
1423 
1424 	if (sc->sc_type == COM_TYPE_HAYESP) {
1425 		int prescaler, speed;
1426 
1427 		/*
1428 		 * Calculate UART clock prescaler.  It should be in
1429 		 * range of 0 .. 3.
1430 		 */
1431 		for (prescaler = 0, speed = t->c_ospeed; prescaler < 4;
1432 		    prescaler++, speed /= 2)
1433 			if ((ospeed = comspeed(speed, sc->sc_frequency,
1434 					       sc->sc_type)) > 0)
1435 				break;
1436 
1437 		if (prescaler == 4)
1438 			return (EINVAL);
1439 		sc->sc_prescaler = prescaler;
1440 	} else
1441 		ospeed = comspeed(t->c_ospeed, sc->sc_frequency, sc->sc_type);
1442 
1443 	/* Check requested parameters. */
1444 	if (ospeed < 0)
1445 		return (EINVAL);
1446 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
1447 		return (EINVAL);
1448 
1449 	/*
1450 	 * For the console, always force CLOCAL and !HUPCL, so that the port
1451 	 * is always active.
1452 	 */
1453 	if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
1454 	    ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
1455 		SET(t->c_cflag, CLOCAL);
1456 		CLR(t->c_cflag, HUPCL);
1457 	}
1458 
1459 	/*
1460 	 * If there were no changes, don't do anything.  This avoids dropping
1461 	 * input and improves performance when all we did was frob things like
1462 	 * VMIN and VTIME.
1463 	 */
1464 	if (tp->t_ospeed == t->c_ospeed &&
1465 	    tp->t_cflag == t->c_cflag)
1466 		return (0);
1467 
1468 	lcr = ISSET(sc->sc_lcr, LCR_SBREAK) | cflag2lcr(t->c_cflag);
1469 
1470 	mutex_spin_enter(&sc->sc_lock);
1471 
1472 	sc->sc_lcr = lcr;
1473 
1474 	/*
1475 	 * If we're not in a mode that assumes a connection is present, then
1476 	 * ignore carrier changes.
1477 	 */
1478 	if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
1479 		sc->sc_msr_dcd = 0;
1480 	else
1481 		sc->sc_msr_dcd = MSR_DCD;
1482 	/*
1483 	 * Set the flow control pins depending on the current flow control
1484 	 * mode.
1485 	 */
1486 	if (ISSET(t->c_cflag, CRTSCTS)) {
1487 		sc->sc_mcr_dtr = MCR_DTR;
1488 		sc->sc_mcr_rts = MCR_RTS;
1489 		sc->sc_msr_cts = MSR_CTS;
1490 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1491 			SET(sc->sc_mcr, MCR_AFE);
1492 		} else {
1493 			sc->sc_efr = EFR_AUTORTS | EFR_AUTOCTS;
1494 		}
1495 	} else if (ISSET(t->c_cflag, MDMBUF)) {
1496 		/*
1497 		 * For DTR/DCD flow control, make sure we don't toggle DTR for
1498 		 * carrier detection.
1499 		 */
1500 		sc->sc_mcr_dtr = 0;
1501 		sc->sc_mcr_rts = MCR_DTR;
1502 		sc->sc_msr_cts = MSR_DCD;
1503 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1504 			CLR(sc->sc_mcr, MCR_AFE);
1505 		} else {
1506 			sc->sc_efr = 0;
1507 		}
1508 	} else {
1509 		/*
1510 		 * If no flow control, then always set RTS.  This will make
1511 		 * the other side happy if it mistakenly thinks we're doing
1512 		 * RTS/CTS flow control.
1513 		 */
1514 		sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
1515 		sc->sc_mcr_rts = 0;
1516 		sc->sc_msr_cts = 0;
1517 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1518 			CLR(sc->sc_mcr, MCR_AFE);
1519 		} else {
1520 			sc->sc_efr = 0;
1521 		}
1522 		if (ISSET(sc->sc_mcr, MCR_DTR))
1523 			SET(sc->sc_mcr, MCR_RTS);
1524 		else
1525 			CLR(sc->sc_mcr, MCR_RTS);
1526 	}
1527 	sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;
1528 
1529 	if (t->c_ospeed == 0 && tp->t_ospeed != 0)
1530 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1531 	else if (t->c_ospeed != 0 && tp->t_ospeed == 0)
1532 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1533 
1534 	sc->sc_dlbl = ospeed;
1535 	sc->sc_dlbh = ospeed >> 8;
1536 
1537 	/*
1538 	 * Set the FIFO threshold based on the receive speed.
1539 	 *
1540 	 *  * If it's a low speed, it's probably a mouse or some other
1541 	 *    interactive device, so set the threshold low.
1542 	 *  * If it's a high speed, trim the trigger level down to prevent
1543 	 *    overflows.
1544 	 *  * Otherwise set it a bit higher.
1545 	 */
1546 	if (sc->sc_type == COM_TYPE_HAYESP) {
1547 		sc->sc_fifo = FIFO_DMA_MODE | FIFO_ENABLE | FIFO_TRIGGER_8;
1548 	} else if (sc->sc_type == COM_TYPE_TEGRA) {
1549 		sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
1550 	} else if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
1551 		if (t->c_ospeed <= 1200)
1552 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
1553 		else if (t->c_ospeed <= 38400)
1554 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_8;
1555 		else
1556 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_4;
1557 	} else {
1558 		sc->sc_fifo = 0;
1559 	}
1560 
1561 	if (sc->sc_type == COM_TYPE_INGENIC)
1562 		sc->sc_fifo |= FIFO_UART_ON;
1563 
1564 	/* And copy to tty. */
1565 	tp->t_ispeed = t->c_ospeed;
1566 	tp->t_ospeed = t->c_ospeed;
1567 	tp->t_cflag = t->c_cflag;
1568 
1569 	if (!sc->sc_heldchange) {
1570 		if (sc->sc_tx_busy) {
1571 			sc->sc_heldtbc = sc->sc_tbc;
1572 			sc->sc_tbc = 0;
1573 			sc->sc_heldchange = 1;
1574 		} else
1575 			com_loadchannelregs(sc);
1576 	}
1577 
1578 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1579 		/* Disable the high water mark. */
1580 		sc->sc_r_hiwat = 0;
1581 		sc->sc_r_lowat = 0;
1582 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1583 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1584 			com_schedrx(sc);
1585 		}
1586 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
1587 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
1588 			com_hwiflow(sc);
1589 		}
1590 	} else {
1591 		sc->sc_r_hiwat = com_rbuf_hiwat;
1592 		sc->sc_r_lowat = com_rbuf_lowat;
1593 	}
1594 
1595 	mutex_spin_exit(&sc->sc_lock);
1596 
1597 	/*
1598 	 * Update the tty layer's idea of the carrier bit, in case we changed
1599 	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
1600 	 * explicit request.
1601 	 */
1602 	if (sc->sc_type == COM_TYPE_INGENIC) {
1603 		/* no DCD here */
1604 		(void) (*tp->t_linesw->l_modem)(tp, 1);
1605 	} else
1606 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, MSR_DCD));
1607 
1608 #ifdef COM_DEBUG
1609 	if (com_debug)
1610 		comstatus(sc, "comparam ");
1611 #endif
1612 
1613 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1614 		if (sc->sc_tx_stopped) {
1615 			sc->sc_tx_stopped = 0;
1616 			comstart(tp);
1617 		}
1618 	}
1619 
1620 	return (0);
1621 }
1622 
1623 void
1624 com_iflush(struct com_softc *sc)
1625 {
1626 	struct com_regs	*regsp = &sc->sc_regs;
1627 	uint8_t fifo;
1628 #ifdef DIAGNOSTIC
1629 	int reg;
1630 #endif
1631 	int timo;
1632 
1633 #ifdef DIAGNOSTIC
1634 	reg = 0xffff;
1635 #endif
1636 	timo = 50000;
1637 	/* flush any pending I/O */
1638 	while (ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)
1639 	    && --timo)
1640 #ifdef DIAGNOSTIC
1641 		reg =
1642 #else
1643 		    (void)
1644 #endif
1645 		    CSR_READ_1(regsp, COM_REG_RXDATA);
1646 #ifdef DIAGNOSTIC
1647 	if (!timo)
1648 		aprint_error_dev(sc->sc_dev, "com_iflush timeout %02x\n", reg);
1649 #endif
1650 
1651 	switch (sc->sc_type) {
1652 	case COM_TYPE_16750:
1653 	case COM_TYPE_DW_APB:
1654 		/*
1655 		 * Reset all Rx/Tx FIFO, preserve current FIFO length.
1656 		 * This should prevent triggering busy interrupt while
1657 		 * manipulating divisors.
1658 		 */
1659 		fifo = CSR_READ_1(regsp, COM_REG_FIFO) & (FIFO_TRIGGER_1 |
1660 		    FIFO_TRIGGER_4 | FIFO_TRIGGER_8 | FIFO_TRIGGER_14);
1661 		CSR_WRITE_1(regsp, COM_REG_FIFO,
1662 		    fifo | FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST);
1663 		delay(100);
1664 		break;
1665 	}
1666 }
1667 
1668 void
1669 com_loadchannelregs(struct com_softc *sc)
1670 {
1671 	struct com_regs *regsp = &sc->sc_regs;
1672 
1673 	/* XXXXX necessary? */
1674 	com_iflush(sc);
1675 
1676 	if (sc->sc_type == COM_TYPE_PXA2x0)
1677 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
1678 	else
1679 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
1680 
1681 	if (sc->sc_type == COM_TYPE_OMAP) {
1682 		/* disable before changing settings */
1683 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
1684 	}
1685 
1686 	if (ISSET(sc->sc_hwflags, COM_HW_FLOW)) {
1687 		KASSERT(sc->sc_type != COM_TYPE_AU1x00);
1688 		KASSERT(sc->sc_type != COM_TYPE_16550_NOERS);
1689 		/* no EFR on alchemy */
1690 		CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
1691 		CSR_WRITE_1(regsp, COM_REG_EFR, sc->sc_efr);
1692 	}
1693 	if (sc->sc_type == COM_TYPE_AU1x00) {
1694 		/* alchemy has single separate 16-bit clock divisor register */
1695 		CSR_WRITE_2(regsp, COM_REG_DLBL, sc->sc_dlbl +
1696 		    (sc->sc_dlbh << 8));
1697 	} else {
1698 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
1699 		CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
1700 		CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
1701 	}
1702 	CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
1703 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active = sc->sc_mcr);
1704 	CSR_WRITE_1(regsp, COM_REG_FIFO, sc->sc_fifo);
1705 	if (sc->sc_type == COM_TYPE_HAYESP) {
1706 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
1707 		    HAYESP_SETPRESCALER);
1708 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
1709 		    sc->sc_prescaler);
1710 	}
1711 	if (sc->sc_type == COM_TYPE_OMAP) {
1712 		/* setup the fifos.  the FCR value is not used as long
1713 		   as SCR[6] and SCR[7] are 0, which they are at reset
1714 		   and we never touch the SCR register */
1715 		uint8_t rx_fifo_trig = 40;
1716 		uint8_t tx_fifo_trig = 60;
1717 		uint8_t rx_start = 8;
1718 		uint8_t rx_halt = 60;
1719 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
1720 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
1721 
1722 		/* enable access to TCR & TLR */
1723 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr | MCR_TCR_TLR);
1724 
1725 		/* write tcr and tlr values */
1726 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
1727 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
1728 
1729 		/* disable access to TCR & TLR */
1730 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr);
1731 
1732 		/* enable again, but mode is based on speed */
1733 		if (sc->sc_tty->t_termios.c_ospeed > 230400) {
1734 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
1735 		} else {
1736 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
1737 		}
1738 	}
1739 
1740 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1741 }
1742 
1743 int
1744 comhwiflow(struct tty *tp, int block)
1745 {
1746 	struct com_softc *sc =
1747 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1748 
1749 	if (COM_ISALIVE(sc) == 0)
1750 		return (0);
1751 
1752 	if (sc->sc_mcr_rts == 0)
1753 		return (0);
1754 
1755 	mutex_spin_enter(&sc->sc_lock);
1756 
1757 	if (block) {
1758 		if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1759 			SET(sc->sc_rx_flags, RX_TTY_BLOCKED);
1760 			com_hwiflow(sc);
1761 		}
1762 	} else {
1763 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1764 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1765 			com_schedrx(sc);
1766 		}
1767 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1768 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED);
1769 			com_hwiflow(sc);
1770 		}
1771 	}
1772 
1773 	mutex_spin_exit(&sc->sc_lock);
1774 	return (1);
1775 }
1776 
1777 /*
1778  * (un)block input via hw flowcontrol
1779  */
1780 void
1781 com_hwiflow(struct com_softc *sc)
1782 {
1783 	struct com_regs *regsp= &sc->sc_regs;
1784 
1785 	if (sc->sc_mcr_rts == 0)
1786 		return;
1787 
1788 	if (ISSET(sc->sc_rx_flags, RX_ANY_BLOCK)) {
1789 		CLR(sc->sc_mcr, sc->sc_mcr_rts);
1790 		CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
1791 	} else {
1792 		SET(sc->sc_mcr, sc->sc_mcr_rts);
1793 		SET(sc->sc_mcr_active, sc->sc_mcr_rts);
1794 	}
1795 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active);
1796 }
1797 
1798 
1799 void
1800 comstart(struct tty *tp)
1801 {
1802 	struct com_softc *sc =
1803 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1804 	struct com_regs *regsp = &sc->sc_regs;
1805 	int s;
1806 
1807 	if (COM_ISALIVE(sc) == 0)
1808 		return;
1809 
1810 	s = spltty();
1811 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
1812 		goto out;
1813 	if (sc->sc_tx_stopped)
1814 		goto out;
1815 	if (!ttypull(tp))
1816 		goto out;
1817 
1818 	/* Grab the first contiguous region of buffer space. */
1819 	{
1820 		u_char *tba;
1821 		int tbc;
1822 
1823 		tba = tp->t_outq.c_cf;
1824 		tbc = ndqb(&tp->t_outq, 0);
1825 
1826 		mutex_spin_enter(&sc->sc_lock);
1827 
1828 		sc->sc_tba = tba;
1829 		sc->sc_tbc = tbc;
1830 	}
1831 
1832 	SET(tp->t_state, TS_BUSY);
1833 	sc->sc_tx_busy = 1;
1834 
1835 	/* Enable transmit completion interrupts if necessary. */
1836 	if (!ISSET(sc->sc_ier, IER_ETXRDY)) {
1837 		SET(sc->sc_ier, IER_ETXRDY);
1838 		CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1839 	}
1840 
1841 	/* Output the first chunk of the contiguous buffer. */
1842 	if (!ISSET(sc->sc_hwflags, COM_HW_NO_TXPRELOAD)) {
1843 		u_int n;
1844 
1845 		n = sc->sc_tbc;
1846 		if (n > sc->sc_fifolen)
1847 			n = sc->sc_fifolen;
1848 		CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
1849 		sc->sc_tbc -= n;
1850 		sc->sc_tba += n;
1851 	}
1852 
1853 	mutex_spin_exit(&sc->sc_lock);
1854 out:
1855 	splx(s);
1856 	return;
1857 }
1858 
1859 /*
1860  * Stop output on a line.
1861  */
1862 void
1863 comstop(struct tty *tp, int flag)
1864 {
1865 	struct com_softc *sc =
1866 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1867 
1868 	mutex_spin_enter(&sc->sc_lock);
1869 	if (ISSET(tp->t_state, TS_BUSY)) {
1870 		/* Stop transmitting at the next chunk. */
1871 		sc->sc_tbc = 0;
1872 		sc->sc_heldtbc = 0;
1873 		if (!ISSET(tp->t_state, TS_TTSTOP))
1874 			SET(tp->t_state, TS_FLUSH);
1875 	}
1876 	mutex_spin_exit(&sc->sc_lock);
1877 }
1878 
1879 void
1880 comdiag(void *arg)
1881 {
1882 	struct com_softc *sc = arg;
1883 	int overflows, floods;
1884 
1885 	mutex_spin_enter(&sc->sc_lock);
1886 	overflows = sc->sc_overflows;
1887 	sc->sc_overflows = 0;
1888 	floods = sc->sc_floods;
1889 	sc->sc_floods = 0;
1890 	sc->sc_errors = 0;
1891 	mutex_spin_exit(&sc->sc_lock);
1892 
1893 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
1894 	    device_xname(sc->sc_dev),
1895 	    overflows, overflows == 1 ? "" : "s",
1896 	    floods, floods == 1 ? "" : "s");
1897 }
1898 
1899 integrate void
1900 com_rxsoft(struct com_softc *sc, struct tty *tp)
1901 {
1902 	int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
1903 	u_char *get, *end;
1904 	u_int cc, scc;
1905 	u_char lsr;
1906 	int code;
1907 
1908 	end = sc->sc_ebuf;
1909 	get = sc->sc_rbget;
1910 	scc = cc = com_rbuf_size - sc->sc_rbavail;
1911 
1912 	if (cc == com_rbuf_size) {
1913 		sc->sc_floods++;
1914 		if (sc->sc_errors++ == 0)
1915 			callout_reset(&sc->sc_diag_callout, 60 * hz,
1916 			    comdiag, sc);
1917 	}
1918 
1919 	/* If not yet open, drop the entire buffer content here */
1920 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
1921 		get += cc << 1;
1922 		if (get >= end)
1923 			get -= com_rbuf_size << 1;
1924 		cc = 0;
1925 	}
1926 	while (cc) {
1927 		code = get[0];
1928 		lsr = get[1];
1929 		if (ISSET(lsr, LSR_OE | LSR_BI | LSR_FE | LSR_PE)) {
1930 			if (ISSET(lsr, LSR_OE)) {
1931 				sc->sc_overflows++;
1932 				if (sc->sc_errors++ == 0)
1933 					callout_reset(&sc->sc_diag_callout,
1934 					    60 * hz, comdiag, sc);
1935 			}
1936 			if (ISSET(lsr, LSR_BI | LSR_FE))
1937 				SET(code, TTY_FE);
1938 			if (ISSET(lsr, LSR_PE))
1939 				SET(code, TTY_PE);
1940 		}
1941 		if ((*rint)(code, tp) == -1) {
1942 			/*
1943 			 * The line discipline's buffer is out of space.
1944 			 */
1945 			if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1946 				/*
1947 				 * We're either not using flow control, or the
1948 				 * line discipline didn't tell us to block for
1949 				 * some reason.  Either way, we have no way to
1950 				 * know when there's more space available, so
1951 				 * just drop the rest of the data.
1952 				 */
1953 				get += cc << 1;
1954 				if (get >= end)
1955 					get -= com_rbuf_size << 1;
1956 				cc = 0;
1957 			} else {
1958 				/*
1959 				 * Don't schedule any more receive processing
1960 				 * until the line discipline tells us there's
1961 				 * space available (through comhwiflow()).
1962 				 * Leave the rest of the data in the input
1963 				 * buffer.
1964 				 */
1965 				SET(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1966 			}
1967 			break;
1968 		}
1969 		get += 2;
1970 		if (get >= end)
1971 			get = sc->sc_rbuf;
1972 		cc--;
1973 	}
1974 
1975 	if (cc != scc) {
1976 		sc->sc_rbget = get;
1977 		mutex_spin_enter(&sc->sc_lock);
1978 
1979 		cc = sc->sc_rbavail += scc - cc;
1980 		/* Buffers should be ok again, release possible block. */
1981 		if (cc >= sc->sc_r_lowat) {
1982 			if (ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
1983 				CLR(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
1984 				SET(sc->sc_ier, IER_ERXRDY);
1985 				if (sc->sc_type == COM_TYPE_PXA2x0)
1986 					SET(sc->sc_ier, IER_ERXTOUT);
1987 				if (sc->sc_type == COM_TYPE_INGENIC ||
1988 				    sc->sc_type == COM_TYPE_TEGRA)
1989 					SET(sc->sc_ier, IER_ERXTOUT);
1990 
1991 				CSR_WRITE_1(&sc->sc_regs, COM_REG_IER,
1992 				    sc->sc_ier);
1993 			}
1994 			if (ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED)) {
1995 				CLR(sc->sc_rx_flags, RX_IBUF_BLOCKED);
1996 				com_hwiflow(sc);
1997 			}
1998 		}
1999 		mutex_spin_exit(&sc->sc_lock);
2000 	}
2001 }
2002 
2003 integrate void
2004 com_txsoft(struct com_softc *sc, struct tty *tp)
2005 {
2006 
2007 	CLR(tp->t_state, TS_BUSY);
2008 	if (ISSET(tp->t_state, TS_FLUSH))
2009 		CLR(tp->t_state, TS_FLUSH);
2010 	else
2011 		ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
2012 	(*tp->t_linesw->l_start)(tp);
2013 }
2014 
2015 integrate void
2016 com_stsoft(struct com_softc *sc, struct tty *tp)
2017 {
2018 	u_char msr, delta;
2019 
2020 	mutex_spin_enter(&sc->sc_lock);
2021 	msr = sc->sc_msr;
2022 	delta = sc->sc_msr_delta;
2023 	sc->sc_msr_delta = 0;
2024 	mutex_spin_exit(&sc->sc_lock);
2025 
2026 	if (ISSET(delta, sc->sc_msr_dcd)) {
2027 		/*
2028 		 * Inform the tty layer that carrier detect changed.
2029 		 */
2030 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(msr, MSR_DCD));
2031 	}
2032 
2033 	if (ISSET(delta, sc->sc_msr_cts)) {
2034 		/* Block or unblock output according to flow control. */
2035 		if (ISSET(msr, sc->sc_msr_cts)) {
2036 			sc->sc_tx_stopped = 0;
2037 			(*tp->t_linesw->l_start)(tp);
2038 		} else {
2039 			sc->sc_tx_stopped = 1;
2040 		}
2041 	}
2042 
2043 #ifdef COM_DEBUG
2044 	if (com_debug)
2045 		comstatus(sc, "com_stsoft");
2046 #endif
2047 }
2048 
2049 void
2050 comsoft(void *arg)
2051 {
2052 	struct com_softc *sc = arg;
2053 	struct tty *tp;
2054 
2055 	if (COM_ISALIVE(sc) == 0)
2056 		return;
2057 
2058 	tp = sc->sc_tty;
2059 
2060 	if (sc->sc_rx_ready) {
2061 		sc->sc_rx_ready = 0;
2062 		com_rxsoft(sc, tp);
2063 	}
2064 
2065 	if (sc->sc_st_check) {
2066 		sc->sc_st_check = 0;
2067 		com_stsoft(sc, tp);
2068 	}
2069 
2070 	if (sc->sc_tx_done) {
2071 		sc->sc_tx_done = 0;
2072 		com_txsoft(sc, tp);
2073 	}
2074 }
2075 
2076 int
2077 comintr(void *arg)
2078 {
2079 	struct com_softc *sc = arg;
2080 	struct com_regs *regsp = &sc->sc_regs;
2081 
2082 	u_char *put, *end;
2083 	u_int cc;
2084 	u_char lsr, iir;
2085 
2086 	if (COM_ISALIVE(sc) == 0)
2087 		return (0);
2088 
2089 	KASSERT(regsp != NULL);
2090 
2091 	mutex_spin_enter(&sc->sc_lock);
2092 	iir = CSR_READ_1(regsp, COM_REG_IIR);
2093 
2094 	/* Handle ns16750-specific busy interrupt. */
2095 	if (sc->sc_type == COM_TYPE_16750 &&
2096 	    (iir & IIR_BUSY) == IIR_BUSY) {
2097 		for (int timeout = 10000;
2098 		    (CSR_READ_1(regsp, COM_REG_USR) & 0x1) != 0; timeout--)
2099 			if (timeout <= 0) {
2100 				aprint_error_dev(sc->sc_dev,
2101 				    "timeout while waiting for BUSY interrupt "
2102 				    "acknowledge\n");
2103 				mutex_spin_exit(&sc->sc_lock);
2104 				return (0);
2105 			}
2106 
2107 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2108 		iir = CSR_READ_1(regsp, COM_REG_IIR);
2109 	}
2110 
2111 	/* DesignWare APB UART BUSY interrupt */
2112 	if (sc->sc_type == COM_TYPE_DW_APB &&
2113 	    (iir & IIR_BUSY) == IIR_BUSY) {
2114 		if ((CSR_READ_1(regsp, COM_REG_USR) & 0x1) != 0) {
2115 			CSR_WRITE_1(regsp, COM_REG_HALT, HALT_CHCFG_EN);
2116 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
2117 			CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
2118 			CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
2119 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2120 			CSR_WRITE_1(regsp, COM_REG_HALT,
2121 			    HALT_CHCFG_EN | HALT_CHCFG_UD);
2122 			for (int timeout = 10000000;
2123 			    (CSR_READ_1(regsp, COM_REG_HALT) & HALT_CHCFG_UD) != 0;
2124 			    timeout--) {
2125 				if (timeout <= 0) {
2126 					aprint_error_dev(sc->sc_dev,
2127 					    "timeout while waiting for HALT "
2128 					    "update acknowledge 0x%x 0x%x\n",
2129 					    CSR_READ_1(regsp, COM_REG_HALT),
2130 					    CSR_READ_1(regsp, COM_REG_USR));
2131 					break;
2132 				}
2133 			}
2134 			CSR_WRITE_1(regsp, COM_REG_HALT, 0);
2135 			(void)CSR_READ_1(regsp, COM_REG_USR);
2136 		} else {
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 		}
2142 	}
2143 
2144 	if (ISSET(iir, IIR_NOPEND)) {
2145 		mutex_spin_exit(&sc->sc_lock);
2146 		return (0);
2147 	}
2148 
2149 	end = sc->sc_ebuf;
2150 	put = sc->sc_rbput;
2151 	cc = sc->sc_rbavail;
2152 
2153 again:	do {
2154 		u_char	msr, delta;
2155 
2156 		lsr = CSR_READ_1(regsp, COM_REG_LSR);
2157 		if (ISSET(lsr, LSR_BI)) {
2158 			int cn_trapped = 0; /* see above: cn_trap() */
2159 
2160 			cn_check_magic(sc->sc_tty->t_dev,
2161 				       CNC_BREAK, com_cnm_state);
2162 			if (cn_trapped)
2163 				continue;
2164 #if defined(KGDB) && !defined(DDB)
2165 			if (ISSET(sc->sc_hwflags, COM_HW_KGDB)) {
2166 				kgdb_connect(1);
2167 				continue;
2168 			}
2169 #endif
2170 		}
2171 
2172 		if (sc->sc_type == COM_TYPE_BCMAUXUART && ISSET(iir, IIR_RXRDY))
2173 			lsr |= LSR_RXRDY;
2174 
2175 		if (ISSET(lsr, LSR_RCV_MASK) &&
2176 		    !ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
2177 			while (cc > 0) {
2178 				int cn_trapped = 0;
2179 				put[0] = CSR_READ_1(regsp, COM_REG_RXDATA);
2180 				put[1] = lsr;
2181 				cn_check_magic(sc->sc_tty->t_dev,
2182 					       put[0], com_cnm_state);
2183 				if (cn_trapped)
2184 					goto next;
2185 				put += 2;
2186 				if (put >= end)
2187 					put = sc->sc_rbuf;
2188 				cc--;
2189 			next:
2190 				lsr = CSR_READ_1(regsp, COM_REG_LSR);
2191 				if (!ISSET(lsr, LSR_RCV_MASK))
2192 					break;
2193 			}
2194 
2195 			/*
2196 			 * Current string of incoming characters ended because
2197 			 * no more data was available or we ran out of space.
2198 			 * Schedule a receive event if any data was received.
2199 			 * If we're out of space, turn off receive interrupts.
2200 			 */
2201 			sc->sc_rbput = put;
2202 			sc->sc_rbavail = cc;
2203 			if (!ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED))
2204 				sc->sc_rx_ready = 1;
2205 
2206 			/*
2207 			 * See if we are in danger of overflowing a buffer. If
2208 			 * so, use hardware flow control to ease the pressure.
2209 			 */
2210 			if (!ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED) &&
2211 			    cc < sc->sc_r_hiwat) {
2212 				SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
2213 				com_hwiflow(sc);
2214 			}
2215 
2216 			/*
2217 			 * If we're out of space, disable receive interrupts
2218 			 * until the queue has drained a bit.
2219 			 */
2220 			if (!cc) {
2221 				SET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
2222 				switch (sc->sc_type) {
2223 				case COM_TYPE_PXA2x0:
2224 					CLR(sc->sc_ier, IER_ERXRDY|IER_ERXTOUT);
2225 					break;
2226 				case COM_TYPE_INGENIC:
2227 				case COM_TYPE_TEGRA:
2228 					CLR(sc->sc_ier,
2229 					    IER_ERXRDY | IER_ERXTOUT);
2230 					break;
2231 				default:
2232 					CLR(sc->sc_ier, IER_ERXRDY);
2233 					break;
2234 				}
2235 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
2236 			}
2237 		} else {
2238 			if ((iir & (IIR_RXRDY|IIR_TXRDY)) == IIR_RXRDY) {
2239 				(void) CSR_READ_1(regsp, COM_REG_RXDATA);
2240 				continue;
2241 			}
2242 		}
2243 
2244 		msr = CSR_READ_1(regsp, COM_REG_MSR);
2245 		delta = msr ^ sc->sc_msr;
2246 		sc->sc_msr = msr;
2247 		if ((sc->sc_pps_state.ppsparam.mode & PPS_CAPTUREBOTH) &&
2248 		    (delta & MSR_DCD)) {
2249 			mutex_spin_enter(&timecounter_lock);
2250 			pps_capture(&sc->sc_pps_state);
2251 			pps_event(&sc->sc_pps_state,
2252 			    (msr & MSR_DCD) ?
2253 			    PPS_CAPTUREASSERT :
2254 			    PPS_CAPTURECLEAR);
2255 			mutex_spin_exit(&timecounter_lock);
2256 		}
2257 
2258 		/*
2259 		 * Process normal status changes
2260 		 */
2261 		if (ISSET(delta, sc->sc_msr_mask)) {
2262 			SET(sc->sc_msr_delta, delta);
2263 
2264 			/*
2265 			 * Stop output immediately if we lose the output
2266 			 * flow control signal or carrier detect.
2267 			 */
2268 			if (ISSET(~msr, sc->sc_msr_mask)) {
2269 				sc->sc_tbc = 0;
2270 				sc->sc_heldtbc = 0;
2271 #ifdef COM_DEBUG
2272 				if (com_debug)
2273 					comstatus(sc, "comintr  ");
2274 #endif
2275 			}
2276 
2277 			sc->sc_st_check = 1;
2278 		}
2279 	} while (!ISSET((iir =
2280 	    CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND) &&
2281 	    /*
2282 	     * Since some device (e.g., ST16C1550) doesn't clear IIR_TXRDY
2283 	     * by IIR read, so we can't do this way: `process all interrupts,
2284 	     * then do TX if possible'.
2285 	     */
2286 	    (iir & IIR_IMASK) != IIR_TXRDY);
2287 
2288 	/*
2289 	 * Read LSR again, since there may be an interrupt between
2290 	 * the last LSR read and IIR read above.
2291 	 */
2292 	lsr = CSR_READ_1(regsp, COM_REG_LSR);
2293 
2294 	/*
2295 	 * See if data can be transmitted as well.
2296 	 * Schedule tx done event if no data left
2297 	 * and tty was marked busy.
2298 	 */
2299 	if (ISSET(lsr, LSR_TXRDY)) {
2300 		/*
2301 		 * If we've delayed a parameter change, do it now, and restart
2302 		 * output.
2303 		 */
2304 		if (sc->sc_heldchange) {
2305 			com_loadchannelregs(sc);
2306 			sc->sc_heldchange = 0;
2307 			sc->sc_tbc = sc->sc_heldtbc;
2308 			sc->sc_heldtbc = 0;
2309 		}
2310 
2311 		/* Output the next chunk of the contiguous buffer, if any. */
2312 		if (sc->sc_tbc > 0) {
2313 			u_int n;
2314 
2315 			n = sc->sc_tbc;
2316 			if (n > sc->sc_fifolen)
2317 				n = sc->sc_fifolen;
2318 			CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
2319 			sc->sc_tbc -= n;
2320 			sc->sc_tba += n;
2321 		} else {
2322 			/* Disable transmit completion interrupts if necessary. */
2323 			if (ISSET(sc->sc_ier, IER_ETXRDY)) {
2324 				CLR(sc->sc_ier, IER_ETXRDY);
2325 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
2326 			}
2327 			if (sc->sc_tx_busy) {
2328 				sc->sc_tx_busy = 0;
2329 				sc->sc_tx_done = 1;
2330 			}
2331 		}
2332 	}
2333 
2334 	if (!ISSET((iir = CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND))
2335 		goto again;
2336 
2337 	mutex_spin_exit(&sc->sc_lock);
2338 
2339 	/* Wake up the poller. */
2340 	softint_schedule(sc->sc_si);
2341 
2342 #ifdef RND_COM
2343 	rnd_add_uint32(&sc->rnd_source, iir | lsr);
2344 #endif
2345 
2346 	return (1);
2347 }
2348 
2349 /*
2350  * The following functions are polled getc and putc routines, shared
2351  * by the console and kgdb glue.
2352  *
2353  * The read-ahead code is so that you can detect pending in-band
2354  * cn_magic in polled mode while doing output rather than having to
2355  * wait until the kernel decides it needs input.
2356  */
2357 
2358 #define MAX_READAHEAD	20
2359 static int com_readahead[MAX_READAHEAD];
2360 static int com_readaheadcount = 0;
2361 
2362 int
2363 com_common_getc(dev_t dev, struct com_regs *regsp)
2364 {
2365 	int s = splserial();
2366 	u_char stat, c;
2367 
2368 	/* got a character from reading things earlier */
2369 	if (com_readaheadcount > 0) {
2370 		int i;
2371 
2372 		c = com_readahead[0];
2373 		for (i = 1; i < com_readaheadcount; i++) {
2374 			com_readahead[i-1] = com_readahead[i];
2375 		}
2376 		com_readaheadcount--;
2377 		splx(s);
2378 		return (c);
2379 	}
2380 
2381 	/* don't block until a character becomes available */
2382 	if (!ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
2383 		splx(s);
2384 		return -1;
2385 	}
2386 
2387 	c = CSR_READ_1(regsp, COM_REG_RXDATA);
2388 	stat = CSR_READ_1(regsp, COM_REG_IIR);
2389 	{
2390 		int cn_trapped = 0;	/* required by cn_trap, see above */
2391 #ifdef DDB
2392 		extern int db_active;
2393 		if (!db_active)
2394 #endif
2395 			cn_check_magic(dev, c, com_cnm_state);
2396 	}
2397 	splx(s);
2398 	return (c);
2399 }
2400 
2401 static void
2402 com_common_putc(dev_t dev, struct com_regs *regsp, int c, int with_readahead)
2403 {
2404 	int s = splserial();
2405 	int cin, stat, timo;
2406 
2407 	if (with_readahead && com_readaheadcount < MAX_READAHEAD
2408 	     && ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
2409 		int cn_trapped = 0;
2410 		cin = CSR_READ_1(regsp, COM_REG_RXDATA);
2411 		stat = CSR_READ_1(regsp, COM_REG_IIR);
2412 		cn_check_magic(dev, cin, com_cnm_state);
2413 		com_readahead[com_readaheadcount++] = cin;
2414 	}
2415 
2416 	/* wait for any pending transmission to finish */
2417 	timo = 150000;
2418 	while (!ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_TXRDY) && --timo)
2419 		continue;
2420 
2421 	CSR_WRITE_1(regsp, COM_REG_TXDATA, c);
2422 	COM_BARRIER(regsp, BR | BW);
2423 
2424 	splx(s);
2425 }
2426 
2427 /*
2428  * Initialize UART for use as console or KGDB line.
2429  */
2430 int
2431 cominit(struct com_regs *regsp, int rate, int frequency, int type,
2432     tcflag_t cflag)
2433 {
2434 
2435 	if (bus_space_map(regsp->cr_iot, regsp->cr_iobase, regsp->cr_nports, 0,
2436 		&regsp->cr_ioh))
2437 		return (ENOMEM); /* ??? */
2438 
2439 	if (type == COM_TYPE_OMAP) {
2440 		/* disable before changing settings */
2441 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
2442 	}
2443 
2444 	rate = comspeed(rate, frequency, type);
2445 	if (rate != -1) {
2446 		if (type == COM_TYPE_AU1x00) {
2447 			/* no EFR on alchemy */
2448 			CSR_WRITE_2(regsp, COM_REG_DLBL, rate);
2449 		} else {
2450 			if ((type != COM_TYPE_16550_NOERS) &&
2451 			    (type != COM_TYPE_INGENIC)) {
2452 				CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
2453 				CSR_WRITE_1(regsp, COM_REG_EFR, 0);
2454 			}
2455 			CSR_WRITE_1(regsp, COM_REG_LCR, LCR_DLAB);
2456 			CSR_WRITE_1(regsp, COM_REG_DLBL, rate & 0xff);
2457 			CSR_WRITE_1(regsp, COM_REG_DLBH, rate >> 8);
2458 		}
2459 	}
2460 	CSR_WRITE_1(regsp, COM_REG_LCR, cflag2lcr(cflag));
2461 	CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2462 
2463 	if (type == COM_TYPE_INGENIC) {
2464 		CSR_WRITE_1(regsp, COM_REG_FIFO,
2465 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
2466 		    FIFO_TRIGGER_1 | FIFO_UART_ON);
2467 	} else {
2468 		CSR_WRITE_1(regsp, COM_REG_FIFO,
2469 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
2470 		    FIFO_TRIGGER_1);
2471 	}
2472 
2473 	if (type == COM_TYPE_OMAP) {
2474 		/* setup the fifos.  the FCR value is not used as long
2475 		   as SCR[6] and SCR[7] are 0, which they are at reset
2476 		   and we never touch the SCR register */
2477 		uint8_t rx_fifo_trig = 40;
2478 		uint8_t tx_fifo_trig = 60;
2479 		uint8_t rx_start = 8;
2480 		uint8_t rx_halt = 60;
2481 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
2482 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
2483 
2484 		/* enable access to TCR & TLR */
2485 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS | MCR_TCR_TLR);
2486 
2487 		/* write tcr and tlr values */
2488 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
2489 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
2490 
2491 		/* disable access to TCR & TLR */
2492 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2493 
2494 		/* enable again, but mode is based on speed */
2495 		if (rate > 230400) {
2496 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
2497 		} else {
2498 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
2499 		}
2500 	}
2501 
2502 	if (type == COM_TYPE_PXA2x0)
2503 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
2504 	else
2505 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
2506 
2507 	return (0);
2508 }
2509 
2510 int
2511 comcnattach1(struct com_regs *regsp, int rate, int frequency, int type,
2512     tcflag_t cflag)
2513 {
2514 	int res;
2515 
2516 	comcons_info.regs = *regsp;
2517 
2518 	res = cominit(&comcons_info.regs, rate, frequency, type, cflag);
2519 	if (res)
2520 		return (res);
2521 
2522 	cn_tab = &comcons;
2523 	cn_init_magic(&com_cnm_state);
2524 	cn_set_magic("\047\001"); /* default magic is BREAK */
2525 
2526 	comcons_info.frequency = frequency;
2527 	comcons_info.type = type;
2528 	comcons_info.rate = rate;
2529 	comcons_info.cflag = cflag;
2530 
2531 	return (0);
2532 }
2533 
2534 int
2535 comcnattach(bus_space_tag_t iot, bus_addr_t iobase, int rate, int frequency,
2536     int type, tcflag_t cflag)
2537 {
2538 	struct com_regs	regs;
2539 
2540 	/*XXX*/
2541 	bus_space_handle_t dummy_bsh;
2542 	memset(&dummy_bsh, 0, sizeof(dummy_bsh));
2543 
2544 	/*
2545 	 * dummy_bsh required because com_init_regs() wants it.  A
2546 	 * real bus_space_handle will be filled in by cominit() later.
2547 	 * XXXJRT Detangle this mess eventually, plz.
2548 	 */
2549 	com_init_regs(&regs, iot, dummy_bsh/*XXX*/, iobase);
2550 
2551 	return comcnattach1(&regs, rate, frequency, type, cflag);
2552 }
2553 
2554 static int
2555 comcnreattach(void)
2556 {
2557 	return comcnattach1(&comcons_info.regs, comcons_info.rate,
2558 	    comcons_info.frequency, comcons_info.type, comcons_info.cflag);
2559 }
2560 
2561 int
2562 comcngetc(dev_t dev)
2563 {
2564 
2565 	return (com_common_getc(dev, &comcons_info.regs));
2566 }
2567 
2568 /*
2569  * Console kernel output character routine.
2570  */
2571 void
2572 comcnputc(dev_t dev, int c)
2573 {
2574 
2575 	com_common_putc(dev, &comcons_info.regs, c, cold);
2576 }
2577 
2578 void
2579 comcnpollc(dev_t dev, int on)
2580 {
2581 
2582 	com_readaheadcount = 0;
2583 }
2584 
2585 #ifdef KGDB
2586 int
2587 com_kgdb_attach1(struct com_regs *regsp, int rate, int frequency, int type,
2588     tcflag_t cflag)
2589 {
2590 	int res;
2591 
2592 	if (bus_space_is_equal(regsp->cr_iot, comcons_info.regs.cr_iot) &&
2593 	    regsp->cr_iobase == comcons_info.regs.cr_iobase) {
2594 #if !defined(DDB)
2595 		return (EBUSY); /* cannot share with console */
2596 #else
2597 		comkgdbregs = *regsp;
2598 		comkgdbregs.cr_ioh = comcons_info.regs.cr_ioh;
2599 #endif
2600 	} else {
2601 		comkgdbregs = *regsp;
2602 		res = cominit(&comkgdbregs, rate, frequency, type, cflag);
2603 		if (res)
2604 			return (res);
2605 
2606 		/*
2607 		 * XXXfvdl this shouldn't be needed, but the cn_magic goo
2608 		 * expects this to be initialized
2609 		 */
2610 		cn_init_magic(&com_cnm_state);
2611 		cn_set_magic("\047\001");
2612 	}
2613 
2614 	kgdb_attach(com_kgdb_getc, com_kgdb_putc, NULL);
2615 	kgdb_dev = 123; /* unneeded, only to satisfy some tests */
2616 
2617 	return (0);
2618 }
2619 
2620 int
2621 com_kgdb_attach(bus_space_tag_t iot, bus_addr_t iobase, int rate,
2622     int frequency, int type, tcflag_t cflag)
2623 {
2624 	struct com_regs regs;
2625 
2626 	com_init_regs(&regs, iot, (bus_space_handle_t)0/*XXX*/, iobase);
2627 
2628 	return com_kgdb_attach1(&regs, rate, frequency, type, cflag);
2629 }
2630 
2631 /* ARGSUSED */
2632 int
2633 com_kgdb_getc(void *arg)
2634 {
2635 
2636 	return (com_common_getc(NODEV, &comkgdbregs));
2637 }
2638 
2639 /* ARGSUSED */
2640 void
2641 com_kgdb_putc(void *arg, int c)
2642 {
2643 
2644 	com_common_putc(NODEV, &comkgdbregs, c, 0);
2645 }
2646 #endif /* KGDB */
2647 
2648 /* helper function to identify the com ports used by
2649  console or KGDB (and not yet autoconf attached) */
2650 int
2651 com_is_console(bus_space_tag_t iot, bus_addr_t iobase, bus_space_handle_t *ioh)
2652 {
2653 	bus_space_handle_t help;
2654 
2655 	if (!comconsattached &&
2656 	    bus_space_is_equal(iot, comcons_info.regs.cr_iot) &&
2657 	    iobase == comcons_info.regs.cr_iobase)
2658 		help = comcons_info.regs.cr_ioh;
2659 #ifdef KGDB
2660 	else if (!com_kgdb_attached &&
2661 	    bus_space_is_equal(iot, comkgdbregs.cr_iot) &&
2662 	    iobase == comkgdbregs.cr_iobase)
2663 		help = comkgdbregs.cr_ioh;
2664 #endif
2665 	else
2666 		return (0);
2667 
2668 	if (ioh)
2669 		*ioh = help;
2670 	return (1);
2671 }
2672 
2673 /*
2674  * this routine exists to serve as a shutdown hook for systems that
2675  * have firmware which doesn't interact properly with a com device in
2676  * FIFO mode.
2677  */
2678 bool
2679 com_cleanup(device_t self, int how)
2680 {
2681 	struct com_softc *sc = device_private(self);
2682 
2683 	if (ISSET(sc->sc_hwflags, COM_HW_FIFO))
2684 		CSR_WRITE_1(&sc->sc_regs, COM_REG_FIFO, 0);
2685 
2686 	return true;
2687 }
2688 
2689 bool
2690 com_suspend(device_t self, const pmf_qual_t *qual)
2691 {
2692 	struct com_softc *sc = device_private(self);
2693 
2694 #if 0
2695 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE) && cn_tab == &comcons)
2696 		cn_tab = &comcons_suspend;
2697 #endif
2698 
2699 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, 0);
2700 	(void)CSR_READ_1(&sc->sc_regs, COM_REG_IIR);
2701 
2702 	return true;
2703 }
2704 
2705 bool
2706 com_resume(device_t self, const pmf_qual_t *qual)
2707 {
2708 	struct com_softc *sc = device_private(self);
2709 
2710 	mutex_spin_enter(&sc->sc_lock);
2711 	com_loadchannelregs(sc);
2712 	mutex_spin_exit(&sc->sc_lock);
2713 
2714 	return true;
2715 }
2716