xref: /netbsd-src/sys/dev/ic/com.c (revision 122b5006ee1bd67145794b4cde92f4fe4781a5ec)
1 /* $NetBSD: com.c,v 1.372 2021/10/30 11:43:17 jmcneill 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 1.372 2021/10/30 11:43:17 jmcneill 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 		if (!prop_dictionary_get_uint(dict, "fifolen", &sc->sc_fifolen)) {
543 			cpr = bus_space_read_4(sc->sc_regs.cr_iot,
544 			    sc->sc_regs.cr_ioh, DW_APB_UART_CPR);
545 			sc->sc_fifolen = __SHIFTOUT(cpr, UART_CPR_FIFO_MODE) * 16;
546 		}
547 		if (sc->sc_fifolen == 0) {
548 			sc->sc_fifolen = 1;
549 			fifo_msg = "DesignWare APB UART, no fifo";
550 			CSR_WRITE_1(regsp, COM_REG_FIFO, 0);
551 		} else {
552 			fifo_msg = "DesignWare APB UART";
553 			SET(sc->sc_hwflags, COM_HW_FIFO);
554 			CSR_WRITE_1(regsp, COM_REG_FIFO,
555 			    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
556 		}
557 		goto fifodelay;
558 	}
559 
560 	sc->sc_fifolen = 1;
561 	/* look for a NS 16550AF UART with FIFOs */
562 	if (sc->sc_type == COM_TYPE_INGENIC) {
563 		CSR_WRITE_1(regsp, COM_REG_FIFO,
564 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
565 		    FIFO_TRIGGER_14 | FIFO_UART_ON);
566 	} else
567 		CSR_WRITE_1(regsp, COM_REG_FIFO,
568 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_14);
569 	delay(100);
570 	if (ISSET(CSR_READ_1(regsp, COM_REG_IIR), IIR_FIFO_MASK)
571 	    == IIR_FIFO_MASK)
572 		if (ISSET(CSR_READ_1(regsp, COM_REG_FIFO), FIFO_TRIGGER_14)
573 		    == FIFO_TRIGGER_14) {
574 			SET(sc->sc_hwflags, COM_HW_FIFO);
575 
576 			fifo_msg = "ns16550a";
577 			sc->sc_fifolen = 16;
578 
579 			/*
580 			 * IIR changes into the EFR if LCR is set to LCR_EERS
581 			 * on 16650s. We also know IIR != 0 at this point.
582 			 * Write 0 into the EFR, and read it. If the result
583 			 * is 0, we have a 16650.
584 			 *
585 			 * Older 16650s were broken; the test to detect them
586 			 * is taken from the Linux driver. Apparently
587 			 * setting DLAB enable gives access to the EFR on
588 			 * these chips.
589 			 */
590 			if (sc->sc_type == COM_TYPE_16650) {
591 				lcr = CSR_READ_1(regsp, COM_REG_LCR);
592 				CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
593 				CSR_WRITE_1(regsp, COM_REG_EFR, 0);
594 				if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
595 					CSR_WRITE_1(regsp, COM_REG_LCR,
596 					    lcr | LCR_DLAB);
597 					if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
598 						CLR(sc->sc_hwflags, COM_HW_FIFO);
599 						sc->sc_fifolen = 0;
600 					} else {
601 						SET(sc->sc_hwflags, COM_HW_FLOW);
602 						sc->sc_fifolen = 32;
603 					}
604 				} else
605 					sc->sc_fifolen = 16;
606 
607 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
608 				if (sc->sc_fifolen == 0)
609 					fifo_msg = "st16650, broken fifo";
610 				else if (sc->sc_fifolen == 32)
611 					fifo_msg = "st16650a";
612 				else
613 					fifo_msg = "ns16550a";
614 			}
615 
616 			/*
617 			 * TL16C750 can enable 64byte FIFO, only when DLAB
618 			 * is 1.  However, some 16750 may always enable.  For
619 			 * example, restrictions according to DLAB in a data
620 			 * sheet for SC16C750 were not described.
621 			 * Please enable 'options COM_16650', supposing you
622 			 * use SC16C750.  Probably 32 bytes of FIFO and HW FLOW
623 			 * should become effective.
624 			 */
625 			if (sc->sc_type == COM_TYPE_16750) {
626 				uint8_t iir1, iir2;
627 				uint8_t fcr = FIFO_ENABLE | FIFO_TRIGGER_14;
628 
629 				lcr = CSR_READ_1(regsp, COM_REG_LCR);
630 				CSR_WRITE_1(regsp, COM_REG_LCR,
631 				    lcr & ~LCR_DLAB);
632 				CSR_WRITE_1(regsp, COM_REG_FIFO,
633 				    fcr | FIFO_64B_ENABLE);
634 				iir1 = CSR_READ_1(regsp, COM_REG_IIR);
635 				CSR_WRITE_1(regsp, COM_REG_FIFO, fcr);
636 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr | LCR_DLAB);
637 				CSR_WRITE_1(regsp, COM_REG_FIFO,
638 				    fcr | FIFO_64B_ENABLE);
639 				iir2 = CSR_READ_1(regsp, COM_REG_IIR);
640 
641 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
642 
643 				if (!ISSET(iir1, IIR_64B_FIFO) &&
644 				    ISSET(iir2, IIR_64B_FIFO)) {
645 					/* It is TL16C750. */
646 					sc->sc_fifolen = 64;
647 					SET(sc->sc_hwflags, COM_HW_AFE);
648 				} else
649 					CSR_WRITE_1(regsp, COM_REG_FIFO, fcr);
650 
651 				if (sc->sc_fifolen == 64)
652 					fifo_msg = "tl16c750";
653 				else
654 					fifo_msg = "ns16750";
655 			}
656 		} else
657 			fifo_msg = "ns16550, broken fifo";
658 	else
659 		fifo_msg = "ns8250 or ns16450, no fifo";
660 	CSR_WRITE_1(regsp, COM_REG_FIFO, 0);
661 
662 fifodelay:
663 	/*
664 	 * Some chips will clear down both Tx and Rx FIFOs when zero is
665 	 * written to com_fifo. If this chip is the console, writing zero
666 	 * results in some of the chip/FIFO description being lost, so delay
667 	 * printing it until now.
668 	 */
669 	delay(10);
670 	if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
671 		aprint_normal(": %s, %d-byte FIFO\n", fifo_msg, sc->sc_fifolen);
672 	} else {
673 		aprint_normal(": %s\n", fifo_msg);
674 	}
675 	if (ISSET(sc->sc_hwflags, COM_HW_TXFIFO_DISABLE)) {
676 		sc->sc_fifolen = 1;
677 		aprint_normal_dev(sc->sc_dev, "txfifo disabled\n");
678 	}
679 
680 fifodone:
681 
682 	tp = tty_alloc();
683 	tp->t_oproc = comstart;
684 	tp->t_param = comparam;
685 	tp->t_hwiflow = comhwiflow;
686 	tp->t_softc = sc;
687 
688 	sc->sc_tty = tp;
689 	sc->sc_rbuf = malloc(com_rbuf_size << 1, M_DEVBUF, M_WAITOK);
690 	sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
691 	sc->sc_rbavail = com_rbuf_size;
692 	sc->sc_ebuf = sc->sc_rbuf + (com_rbuf_size << 1);
693 
694 	tty_attach(tp);
695 
696 	if (!ISSET(sc->sc_hwflags, COM_HW_NOIEN))
697 		SET(sc->sc_mcr, MCR_IENABLE);
698 
699 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
700 		int maj;
701 
702 		/* locate the major number */
703 		maj = cdevsw_lookup_major(&com_cdevsw);
704 
705 		tp->t_dev = cn_tab->cn_dev = makedev(maj,
706 						     device_unit(sc->sc_dev));
707 
708 		aprint_normal_dev(sc->sc_dev, "console\n");
709 	}
710 
711 #ifdef KGDB
712 	/*
713 	 * Allow kgdb to "take over" this port.  If this is
714 	 * not the console and is the kgdb device, it has
715 	 * exclusive use.  If it's the console _and_ the
716 	 * kgdb device, it doesn't.
717 	 */
718 	if (bus_space_is_equal(regsp->cr_iot, comkgdbregs.cr_iot) &&
719 	    regsp->cr_iobase == comkgdbregs.cr_iobase) {
720 		if (!ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
721 			com_kgdb_attached = 1;
722 
723 			SET(sc->sc_hwflags, COM_HW_KGDB);
724 		}
725 		aprint_normal_dev(sc->sc_dev, "kgdb\n");
726 	}
727 #endif
728 
729 	sc->sc_si = softint_establish(SOFTINT_SERIAL, comsoft, sc);
730 
731 #ifdef RND_COM
732 	rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
733 			  RND_TYPE_TTY, RND_FLAG_DEFAULT);
734 #endif
735 
736 	/* if there are no enable/disable functions, assume the device
737 	   is always enabled */
738 	if (!sc->enable)
739 		sc->enabled = 1;
740 
741 	com_config(sc);
742 
743 	SET(sc->sc_hwflags, COM_HW_DEV_OK);
744 
745 	if (sc->sc_poll_ticks != 0)
746 		callout_schedule(&sc->sc_poll_callout, sc->sc_poll_ticks);
747 }
748 
749 void
750 com_config(struct com_softc *sc)
751 {
752 	struct com_regs *regsp = &sc->sc_regs;
753 
754 	/* Disable interrupts before configuring the device. */
755 	if (sc->sc_type == COM_TYPE_PXA2x0)
756 		sc->sc_ier = IER_EUART;
757 	else
758 		sc->sc_ier = 0;
759 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
760 	(void) CSR_READ_1(regsp, COM_REG_IIR);
761 
762 	/* Look for a Hayes ESP board. */
763 	if (sc->sc_type == COM_TYPE_HAYESP) {
764 
765 		/* Set 16550 compatibility mode */
766 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
767 				  HAYESP_SETMODE);
768 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
769 				  HAYESP_MODE_FIFO|HAYESP_MODE_RTS|
770 				  HAYESP_MODE_SCALE);
771 
772 		/* Set RTS/CTS flow control */
773 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
774 				  HAYESP_SETFLOWTYPE);
775 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
776 				  HAYESP_FLOW_RTS);
777 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
778 				  HAYESP_FLOW_CTS);
779 
780 		/* Set flow control levels */
781 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
782 				  HAYESP_SETRXFLOW);
783 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
784 				  HAYESP_HIBYTE(HAYESP_RXHIWMARK));
785 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
786 				  HAYESP_LOBYTE(HAYESP_RXHIWMARK));
787 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
788 				  HAYESP_HIBYTE(HAYESP_RXLOWMARK));
789 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
790 				  HAYESP_LOBYTE(HAYESP_RXLOWMARK));
791 	}
792 
793 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE|COM_HW_KGDB))
794 		com_enable_debugport(sc);
795 }
796 
797 #if 0
798 static int
799 comcngetc_detached(dev_t dev)
800 {
801 	return 0;
802 }
803 
804 static void
805 comcnputc_detached(dev_t dev, int c)
806 {
807 }
808 #endif
809 
810 int
811 com_detach(device_t self, int flags)
812 {
813 	struct com_softc *sc = device_private(self);
814 	int maj, mn;
815 
816 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
817 		return EBUSY;
818 
819 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE) &&
820 	    (flags & DETACH_SHUTDOWN) != 0)
821 		return EBUSY;
822 
823 	if (sc->disable != NULL && sc->enabled != 0) {
824 		(*sc->disable)(sc);
825 		sc->enabled = 0;
826 	}
827 
828 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
829 		comconsattached = 0;
830 		cn_tab = NULL;
831 	}
832 
833 	/* locate the major number */
834 	maj = cdevsw_lookup_major(&com_cdevsw);
835 
836 	/* Nuke the vnodes for any open instances. */
837 	mn = device_unit(self);
838 	vdevgone(maj, mn, mn, VCHR);
839 
840 	mn |= COMDIALOUT_MASK;
841 	vdevgone(maj, mn, mn, VCHR);
842 
843 	if (sc->sc_rbuf == NULL) {
844 		/*
845 		 * Ring buffer allocation failed in the com_attach_subr,
846 		 * only the tty is allocated, and nothing else.
847 		 */
848 		tty_free(sc->sc_tty);
849 		return 0;
850 	}
851 
852 	/* Free the receive buffer. */
853 	free(sc->sc_rbuf, M_DEVBUF);
854 
855 	/* Detach and free the tty. */
856 	tty_detach(sc->sc_tty);
857 	tty_free(sc->sc_tty);
858 
859 	/* Unhook the soft interrupt handler. */
860 	softint_disestablish(sc->sc_si);
861 
862 #ifdef RND_COM
863 	/* Unhook the entropy source. */
864 	rnd_detach_source(&sc->rnd_source);
865 #endif
866 	callout_destroy(&sc->sc_diag_callout);
867 
868 	/* Destroy the lock. */
869 	mutex_destroy(&sc->sc_lock);
870 
871 	return (0);
872 }
873 
874 void
875 com_shutdown(struct com_softc *sc)
876 {
877 	struct tty *tp = sc->sc_tty;
878 
879 	mutex_spin_enter(&sc->sc_lock);
880 
881 	/* If we were asserting flow control, then deassert it. */
882 	SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
883 	com_hwiflow(sc);
884 
885 	/* Clear any break condition set with TIOCSBRK. */
886 	com_break(sc, 0);
887 
888 	/*
889 	 * Hang up if necessary.  Wait a bit, so the other side has time to
890 	 * notice even if we immediately open the port again.
891 	 * Avoid tsleeping above splhigh().
892 	 */
893 	if (ISSET(tp->t_cflag, HUPCL)) {
894 		com_modem(sc, 0);
895 		microuptime(&sc->sc_hup_pending);
896 		sc->sc_hup_pending.tv_sec++;
897 	}
898 
899 	/* Turn off interrupts. */
900 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
901 		sc->sc_ier = IER_ERLS; /* interrupt on line break */
902 		if ((sc->sc_type == COM_TYPE_PXA2x0) ||
903 		    (sc->sc_type == COM_TYPE_INGENIC) ||
904 		    (sc->sc_type == COM_TYPE_TEGRA))
905 			sc->sc_ier |= IER_ERXTOUT;
906 	} else
907 		sc->sc_ier = 0;
908 
909 	if (sc->sc_type == COM_TYPE_PXA2x0)
910 		sc->sc_ier |= IER_EUART;
911 
912 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
913 
914 	mutex_spin_exit(&sc->sc_lock);
915 
916 	if (sc->disable) {
917 #ifdef DIAGNOSTIC
918 		if (!sc->enabled)
919 			panic("com_shutdown: not enabled?");
920 #endif
921 		(*sc->disable)(sc);
922 		sc->enabled = 0;
923 	}
924 }
925 
926 int
927 comopen(dev_t dev, int flag, int mode, struct lwp *l)
928 {
929 	struct com_softc *sc;
930 	struct tty *tp;
931 	int s;
932 	int error;
933 
934 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
935 	if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK) ||
936 		sc->sc_rbuf == NULL)
937 		return (ENXIO);
938 
939 	if (!device_is_active(sc->sc_dev))
940 		return (ENXIO);
941 
942 #ifdef KGDB
943 	/*
944 	 * If this is the kgdb port, no other use is permitted.
945 	 */
946 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
947 		return (EBUSY);
948 #endif
949 
950 	tp = sc->sc_tty;
951 
952 	/*
953 	 * If the device is exclusively for kernel use, deny userland
954 	 * open.
955 	 */
956 	if (ISSET(tp->t_state, TS_KERN_ONLY))
957 		return (EBUSY);
958 
959 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
960 		return (EBUSY);
961 
962 	s = spltty();
963 
964 	/*
965 	 * Do the following iff this is a first open.
966 	 */
967 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
968 		struct termios t;
969 		struct timeval now, diff;
970 
971 		tp->t_dev = dev;
972 
973 		if (sc->enable) {
974 			if ((*sc->enable)(sc)) {
975 				splx(s);
976 				aprint_error_dev(sc->sc_dev,
977 				    "device enable failed\n");
978 				return (EIO);
979 			}
980 			mutex_spin_enter(&sc->sc_lock);
981 			sc->enabled = 1;
982 			com_config(sc);
983 		} else {
984 			mutex_spin_enter(&sc->sc_lock);
985 		}
986 
987 		if (timerisset(&sc->sc_hup_pending)) {
988 			microuptime(&now);
989 			while (timercmp(&now, &sc->sc_hup_pending, <)) {
990 				timersub(&sc->sc_hup_pending, &now, &diff);
991 				const int ms = diff.tv_sec * 1000 +
992 				    diff.tv_usec / 1000;
993 				kpause(ttclos, false, uimax(mstohz(ms), 1),
994 				    &sc->sc_lock);
995 				microuptime(&now);
996 			}
997 			timerclear(&sc->sc_hup_pending);
998 		}
999 
1000 		/* Turn on interrupts. */
1001 		sc->sc_ier = IER_ERXRDY | IER_ERLS;
1002 		if (!ISSET(tp->t_cflag, CLOCAL))
1003 			sc->sc_ier |= IER_EMSC;
1004 
1005 		if (sc->sc_type == COM_TYPE_PXA2x0)
1006 			sc->sc_ier |= IER_EUART | IER_ERXTOUT;
1007 		else if (sc->sc_type == COM_TYPE_INGENIC ||
1008 			 sc->sc_type == COM_TYPE_TEGRA)
1009 			sc->sc_ier |= IER_ERXTOUT;
1010 		CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
1011 
1012 		/* Fetch the current modem control status, needed later. */
1013 		sc->sc_msr = CSR_READ_1(&sc->sc_regs, COM_REG_MSR);
1014 
1015 		/* Clear PPS capture state on first open. */
1016 		mutex_spin_enter(&timecounter_lock);
1017 		memset(&sc->sc_pps_state, 0, sizeof(sc->sc_pps_state));
1018 		sc->sc_pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
1019 		pps_init(&sc->sc_pps_state);
1020 		mutex_spin_exit(&timecounter_lock);
1021 
1022 		mutex_spin_exit(&sc->sc_lock);
1023 
1024 		/*
1025 		 * Initialize the termios status to the defaults.  Add in the
1026 		 * sticky bits from TIOCSFLAGS.
1027 		 */
1028 		if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
1029 			t.c_ospeed = comcons_info.rate;
1030 			t.c_cflag = comcons_info.cflag;
1031 		} else {
1032 			t.c_ospeed = TTYDEF_SPEED;
1033 			t.c_cflag = TTYDEF_CFLAG;
1034 		}
1035 		t.c_ispeed = t.c_ospeed;
1036 		if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
1037 			SET(t.c_cflag, CLOCAL);
1038 		if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
1039 			SET(t.c_cflag, CRTSCTS);
1040 		if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
1041 			SET(t.c_cflag, MDMBUF);
1042 		/* Make sure comparam() will do something. */
1043 		tp->t_ospeed = 0;
1044 		(void) comparam(tp, &t);
1045 		tp->t_iflag = TTYDEF_IFLAG;
1046 		tp->t_oflag = TTYDEF_OFLAG;
1047 		tp->t_lflag = TTYDEF_LFLAG;
1048 		ttychars(tp);
1049 		ttsetwater(tp);
1050 
1051 		mutex_spin_enter(&sc->sc_lock);
1052 
1053 		/*
1054 		 * Turn on DTR.  We must always do this, even if carrier is not
1055 		 * present, because otherwise we'd have to use TIOCSDTR
1056 		 * immediately after setting CLOCAL, which applications do not
1057 		 * expect.  We always assert DTR while the device is open
1058 		 * unless explicitly requested to deassert it.
1059 		 */
1060 		com_modem(sc, 1);
1061 
1062 		/* Clear the input ring, and unblock. */
1063 		sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
1064 		sc->sc_rbavail = com_rbuf_size;
1065 		com_iflush(sc);
1066 		CLR(sc->sc_rx_flags, RX_ANY_BLOCK);
1067 		com_hwiflow(sc);
1068 
1069 #ifdef COM_DEBUG
1070 		if (com_debug)
1071 			comstatus(sc, "comopen  ");
1072 #endif
1073 
1074 		mutex_spin_exit(&sc->sc_lock);
1075 	}
1076 
1077 	splx(s);
1078 
1079 	error = ttyopen(tp, COMDIALOUT(dev), ISSET(flag, O_NONBLOCK));
1080 	if (error)
1081 		goto bad;
1082 
1083 	error = (*tp->t_linesw->l_open)(dev, tp);
1084 	if (error)
1085 		goto bad;
1086 
1087 	return (0);
1088 
1089 bad:
1090 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
1091 		/*
1092 		 * We failed to open the device, and nobody else had it opened.
1093 		 * Clean up the state as appropriate.
1094 		 */
1095 		com_shutdown(sc);
1096 	}
1097 
1098 	return (error);
1099 }
1100 
1101 int
1102 comclose(dev_t dev, int flag, int mode, struct lwp *l)
1103 {
1104 	struct com_softc *sc =
1105 	    device_lookup_private(&com_cd, COMUNIT(dev));
1106 	struct tty *tp = sc->sc_tty;
1107 
1108 	/* XXX This is for cons.c. */
1109 	if (!ISSET(tp->t_state, TS_ISOPEN))
1110 		return (0);
1111 	/*
1112 	 * If the device is exclusively for kernel use, deny userland
1113 	 * close.
1114 	 */
1115 	if (ISSET(tp->t_state, TS_KERN_ONLY))
1116 		return (0);
1117 
1118 	(*tp->t_linesw->l_close)(tp, flag);
1119 	ttyclose(tp);
1120 
1121 	if (COM_ISALIVE(sc) == 0)
1122 		return (0);
1123 
1124 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
1125 		/*
1126 		 * Although we got a last close, the device may still be in
1127 		 * use; e.g. if this was the dialout node, and there are still
1128 		 * processes waiting for carrier on the non-dialout node.
1129 		 */
1130 		com_shutdown(sc);
1131 	}
1132 
1133 	return (0);
1134 }
1135 
1136 int
1137 comread(dev_t dev, struct uio *uio, int flag)
1138 {
1139 	struct com_softc *sc =
1140 	    device_lookup_private(&com_cd, COMUNIT(dev));
1141 	struct tty *tp = sc->sc_tty;
1142 
1143 	if (COM_ISALIVE(sc) == 0)
1144 		return (EIO);
1145 
1146 	return ((*tp->t_linesw->l_read)(tp, uio, flag));
1147 }
1148 
1149 int
1150 comwrite(dev_t dev, struct uio *uio, int flag)
1151 {
1152 	struct com_softc *sc =
1153 	    device_lookup_private(&com_cd, COMUNIT(dev));
1154 	struct tty *tp = sc->sc_tty;
1155 
1156 	if (COM_ISALIVE(sc) == 0)
1157 		return (EIO);
1158 
1159 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
1160 }
1161 
1162 int
1163 compoll(dev_t dev, int events, struct lwp *l)
1164 {
1165 	struct com_softc *sc =
1166 	    device_lookup_private(&com_cd, COMUNIT(dev));
1167 	struct tty *tp = sc->sc_tty;
1168 
1169 	if (COM_ISALIVE(sc) == 0)
1170 		return (POLLHUP);
1171 
1172 	return ((*tp->t_linesw->l_poll)(tp, events, l));
1173 }
1174 
1175 struct tty *
1176 comtty(dev_t dev)
1177 {
1178 	struct com_softc *sc =
1179 	    device_lookup_private(&com_cd, COMUNIT(dev));
1180 	struct tty *tp = sc->sc_tty;
1181 
1182 	return (tp);
1183 }
1184 
1185 int
1186 comioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
1187 {
1188 	struct com_softc *sc;
1189 	struct tty *tp;
1190 	int error;
1191 
1192 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
1193 	if (sc == NULL)
1194 		return ENXIO;
1195 	if (COM_ISALIVE(sc) == 0)
1196 		return (EIO);
1197 
1198 	tp = sc->sc_tty;
1199 
1200 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
1201 	if (error != EPASSTHROUGH)
1202 		return (error);
1203 
1204 	error = ttioctl(tp, cmd, data, flag, l);
1205 	if (error != EPASSTHROUGH)
1206 		return (error);
1207 
1208 	error = 0;
1209 	switch (cmd) {
1210 	case TIOCSFLAGS:
1211 		error = kauth_authorize_device_tty(l->l_cred,
1212 		    KAUTH_DEVICE_TTY_PRIVSET, tp);
1213 		break;
1214 	default:
1215 		/* nothing */
1216 		break;
1217 	}
1218 	if (error) {
1219 		return error;
1220 	}
1221 
1222 	mutex_spin_enter(&sc->sc_lock);
1223 
1224 	switch (cmd) {
1225 	case TIOCSBRK:
1226 		com_break(sc, 1);
1227 		break;
1228 
1229 	case TIOCCBRK:
1230 		com_break(sc, 0);
1231 		break;
1232 
1233 	case TIOCSDTR:
1234 		com_modem(sc, 1);
1235 		break;
1236 
1237 	case TIOCCDTR:
1238 		com_modem(sc, 0);
1239 		break;
1240 
1241 	case TIOCGFLAGS:
1242 		*(int *)data = sc->sc_swflags;
1243 		break;
1244 
1245 	case TIOCSFLAGS:
1246 		sc->sc_swflags = *(int *)data;
1247 		break;
1248 
1249 	case TIOCMSET:
1250 	case TIOCMBIS:
1251 	case TIOCMBIC:
1252 		tiocm_to_com(sc, cmd, *(int *)data);
1253 		break;
1254 
1255 	case TIOCMGET:
1256 		*(int *)data = com_to_tiocm(sc);
1257 		break;
1258 
1259 	case PPS_IOC_CREATE:
1260 	case PPS_IOC_DESTROY:
1261 	case PPS_IOC_GETPARAMS:
1262 	case PPS_IOC_SETPARAMS:
1263 	case PPS_IOC_GETCAP:
1264 	case PPS_IOC_FETCH:
1265 #ifdef PPS_SYNC
1266 	case PPS_IOC_KCBIND:
1267 #endif
1268 		mutex_spin_enter(&timecounter_lock);
1269 		error = pps_ioctl(cmd, data, &sc->sc_pps_state);
1270 		mutex_spin_exit(&timecounter_lock);
1271 		break;
1272 
1273 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
1274 		mutex_spin_enter(&timecounter_lock);
1275 #ifndef PPS_TRAILING_EDGE
1276 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1277 		    &sc->sc_pps_state.ppsinfo.assert_timestamp);
1278 #else
1279 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1280 		    &sc->sc_pps_state.ppsinfo.clear_timestamp);
1281 #endif
1282 		mutex_spin_exit(&timecounter_lock);
1283 		break;
1284 
1285 	default:
1286 		error = EPASSTHROUGH;
1287 		break;
1288 	}
1289 
1290 	mutex_spin_exit(&sc->sc_lock);
1291 
1292 #ifdef COM_DEBUG
1293 	if (com_debug)
1294 		comstatus(sc, "comioctl ");
1295 #endif
1296 
1297 	return (error);
1298 }
1299 
1300 integrate void
1301 com_schedrx(struct com_softc *sc)
1302 {
1303 
1304 	sc->sc_rx_ready = 1;
1305 
1306 	/* Wake up the poller. */
1307 	softint_schedule(sc->sc_si);
1308 }
1309 
1310 void
1311 com_break(struct com_softc *sc, int onoff)
1312 {
1313 
1314 	if (onoff)
1315 		SET(sc->sc_lcr, LCR_SBREAK);
1316 	else
1317 		CLR(sc->sc_lcr, LCR_SBREAK);
1318 
1319 	if (!sc->sc_heldchange) {
1320 		if (sc->sc_tx_busy) {
1321 			sc->sc_heldtbc = sc->sc_tbc;
1322 			sc->sc_tbc = 0;
1323 			sc->sc_heldchange = 1;
1324 		} else
1325 			com_loadchannelregs(sc);
1326 	}
1327 }
1328 
1329 void
1330 com_modem(struct com_softc *sc, int onoff)
1331 {
1332 
1333 	if (sc->sc_mcr_dtr == 0)
1334 		return;
1335 
1336 	if (onoff)
1337 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1338 	else
1339 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
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 void
1352 tiocm_to_com(struct com_softc *sc, u_long how, int ttybits)
1353 {
1354 	u_char combits;
1355 
1356 	combits = 0;
1357 	if (ISSET(ttybits, TIOCM_DTR))
1358 		SET(combits, MCR_DTR);
1359 	if (ISSET(ttybits, TIOCM_RTS))
1360 		SET(combits, MCR_RTS);
1361 
1362 	switch (how) {
1363 	case TIOCMBIC:
1364 		CLR(sc->sc_mcr, combits);
1365 		break;
1366 
1367 	case TIOCMBIS:
1368 		SET(sc->sc_mcr, combits);
1369 		break;
1370 
1371 	case TIOCMSET:
1372 		CLR(sc->sc_mcr, MCR_DTR | MCR_RTS);
1373 		SET(sc->sc_mcr, combits);
1374 		break;
1375 	}
1376 
1377 	if (!sc->sc_heldchange) {
1378 		if (sc->sc_tx_busy) {
1379 			sc->sc_heldtbc = sc->sc_tbc;
1380 			sc->sc_tbc = 0;
1381 			sc->sc_heldchange = 1;
1382 		} else
1383 			com_loadchannelregs(sc);
1384 	}
1385 }
1386 
1387 int
1388 com_to_tiocm(struct com_softc *sc)
1389 {
1390 	u_char combits;
1391 	int ttybits = 0;
1392 
1393 	combits = sc->sc_mcr;
1394 	if (ISSET(combits, MCR_DTR))
1395 		SET(ttybits, TIOCM_DTR);
1396 	if (ISSET(combits, MCR_RTS))
1397 		SET(ttybits, TIOCM_RTS);
1398 
1399 	combits = sc->sc_msr;
1400 	if (sc->sc_type == COM_TYPE_INGENIC) {
1401 		SET(ttybits, TIOCM_CD);
1402 	} else {
1403 		if (ISSET(combits, MSR_DCD))
1404 			SET(ttybits, TIOCM_CD);
1405 	}
1406 	if (ISSET(combits, MSR_CTS))
1407 		SET(ttybits, TIOCM_CTS);
1408 	if (ISSET(combits, MSR_DSR))
1409 		SET(ttybits, TIOCM_DSR);
1410 	if (ISSET(combits, MSR_RI | MSR_TERI))
1411 		SET(ttybits, TIOCM_RI);
1412 
1413 	if (ISSET(sc->sc_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS | IER_EMSC))
1414 		SET(ttybits, TIOCM_LE);
1415 
1416 	return (ttybits);
1417 }
1418 
1419 static u_char
1420 cflag2lcr(tcflag_t cflag)
1421 {
1422 	u_char lcr = 0;
1423 
1424 	switch (ISSET(cflag, CSIZE)) {
1425 	case CS5:
1426 		SET(lcr, LCR_5BITS);
1427 		break;
1428 	case CS6:
1429 		SET(lcr, LCR_6BITS);
1430 		break;
1431 	case CS7:
1432 		SET(lcr, LCR_7BITS);
1433 		break;
1434 	case CS8:
1435 		SET(lcr, LCR_8BITS);
1436 		break;
1437 	}
1438 	if (ISSET(cflag, PARENB)) {
1439 		SET(lcr, LCR_PENAB);
1440 		if (!ISSET(cflag, PARODD))
1441 			SET(lcr, LCR_PEVEN);
1442 	}
1443 	if (ISSET(cflag, CSTOPB))
1444 		SET(lcr, LCR_STOPB);
1445 
1446 	return (lcr);
1447 }
1448 
1449 int
1450 comparam(struct tty *tp, struct termios *t)
1451 {
1452 	struct com_softc *sc =
1453 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1454 	int ospeed;
1455 	u_char lcr;
1456 
1457 	if (COM_ISALIVE(sc) == 0)
1458 		return (EIO);
1459 
1460 	if (sc->sc_type == COM_TYPE_HAYESP) {
1461 		int prescaler, speed;
1462 
1463 		/*
1464 		 * Calculate UART clock prescaler.  It should be in
1465 		 * range of 0 .. 3.
1466 		 */
1467 		for (prescaler = 0, speed = t->c_ospeed; prescaler < 4;
1468 		    prescaler++, speed /= 2)
1469 			if ((ospeed = comspeed(speed, sc->sc_frequency,
1470 					       sc->sc_type)) > 0)
1471 				break;
1472 
1473 		if (prescaler == 4)
1474 			return (EINVAL);
1475 		sc->sc_prescaler = prescaler;
1476 	} else
1477 		ospeed = comspeed(t->c_ospeed, sc->sc_frequency, sc->sc_type);
1478 
1479 	/* Check requested parameters. */
1480 	if (ospeed < 0)
1481 		return (EINVAL);
1482 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
1483 		return (EINVAL);
1484 
1485 	/*
1486 	 * For the console, always force CLOCAL and !HUPCL, so that the port
1487 	 * is always active.
1488 	 */
1489 	if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
1490 	    ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
1491 		SET(t->c_cflag, CLOCAL);
1492 		CLR(t->c_cflag, HUPCL);
1493 	}
1494 
1495 	/*
1496 	 * If there were no changes, don't do anything.  This avoids dropping
1497 	 * input and improves performance when all we did was frob things like
1498 	 * VMIN and VTIME.
1499 	 */
1500 	if (tp->t_ospeed == t->c_ospeed &&
1501 	    tp->t_cflag == t->c_cflag)
1502 		return (0);
1503 
1504 	lcr = ISSET(sc->sc_lcr, LCR_SBREAK) | cflag2lcr(t->c_cflag);
1505 
1506 	mutex_spin_enter(&sc->sc_lock);
1507 
1508 	sc->sc_lcr = lcr;
1509 
1510 	/*
1511 	 * If we're not in a mode that assumes a connection is present, then
1512 	 * ignore carrier changes.
1513 	 */
1514 	if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
1515 		sc->sc_msr_dcd = 0;
1516 	else
1517 		sc->sc_msr_dcd = MSR_DCD;
1518 	/*
1519 	 * Set the flow control pins depending on the current flow control
1520 	 * mode.
1521 	 */
1522 	if (ISSET(t->c_cflag, CRTSCTS)) {
1523 		sc->sc_mcr_dtr = MCR_DTR;
1524 		sc->sc_mcr_rts = MCR_RTS;
1525 		sc->sc_msr_cts = MSR_CTS;
1526 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1527 			SET(sc->sc_mcr, MCR_AFE);
1528 		} else {
1529 			sc->sc_efr = EFR_AUTORTS | EFR_AUTOCTS;
1530 		}
1531 	} else if (ISSET(t->c_cflag, MDMBUF)) {
1532 		/*
1533 		 * For DTR/DCD flow control, make sure we don't toggle DTR for
1534 		 * carrier detection.
1535 		 */
1536 		sc->sc_mcr_dtr = 0;
1537 		sc->sc_mcr_rts = MCR_DTR;
1538 		sc->sc_msr_cts = MSR_DCD;
1539 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1540 			CLR(sc->sc_mcr, MCR_AFE);
1541 		} else {
1542 			sc->sc_efr = 0;
1543 		}
1544 	} else {
1545 		/*
1546 		 * If no flow control, then always set RTS.  This will make
1547 		 * the other side happy if it mistakenly thinks we're doing
1548 		 * RTS/CTS flow control.
1549 		 */
1550 		sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
1551 		sc->sc_mcr_rts = 0;
1552 		sc->sc_msr_cts = 0;
1553 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1554 			CLR(sc->sc_mcr, MCR_AFE);
1555 		} else {
1556 			sc->sc_efr = 0;
1557 		}
1558 		if (ISSET(sc->sc_mcr, MCR_DTR))
1559 			SET(sc->sc_mcr, MCR_RTS);
1560 		else
1561 			CLR(sc->sc_mcr, MCR_RTS);
1562 	}
1563 	sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;
1564 
1565 	if (t->c_ospeed == 0 && tp->t_ospeed != 0)
1566 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1567 	else if (t->c_ospeed != 0 && tp->t_ospeed == 0)
1568 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1569 
1570 	sc->sc_dlbl = ospeed;
1571 	sc->sc_dlbh = ospeed >> 8;
1572 
1573 	/*
1574 	 * Set the FIFO threshold based on the receive speed.
1575 	 *
1576 	 *  * If it's a low speed, it's probably a mouse or some other
1577 	 *    interactive device, so set the threshold low.
1578 	 *  * If it's a high speed, trim the trigger level down to prevent
1579 	 *    overflows.
1580 	 *  * Otherwise set it a bit higher.
1581 	 */
1582 	if (sc->sc_type == COM_TYPE_HAYESP) {
1583 		sc->sc_fifo = FIFO_DMA_MODE | FIFO_ENABLE | FIFO_TRIGGER_8;
1584 	} else if (sc->sc_type == COM_TYPE_TEGRA) {
1585 		sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
1586 	} else if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
1587 		if (t->c_ospeed <= 1200)
1588 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
1589 		else if (t->c_ospeed <= 38400)
1590 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_8;
1591 		else
1592 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_4;
1593 	} else {
1594 		sc->sc_fifo = 0;
1595 	}
1596 
1597 	if (sc->sc_type == COM_TYPE_INGENIC)
1598 		sc->sc_fifo |= FIFO_UART_ON;
1599 
1600 	/* And copy to tty. */
1601 	tp->t_ispeed = t->c_ospeed;
1602 	tp->t_ospeed = t->c_ospeed;
1603 	tp->t_cflag = t->c_cflag;
1604 
1605 	if (!sc->sc_heldchange) {
1606 		if (sc->sc_tx_busy) {
1607 			sc->sc_heldtbc = sc->sc_tbc;
1608 			sc->sc_tbc = 0;
1609 			sc->sc_heldchange = 1;
1610 		} else
1611 			com_loadchannelregs(sc);
1612 	}
1613 
1614 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1615 		/* Disable the high water mark. */
1616 		sc->sc_r_hiwat = 0;
1617 		sc->sc_r_lowat = 0;
1618 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1619 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1620 			com_schedrx(sc);
1621 		}
1622 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
1623 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
1624 			com_hwiflow(sc);
1625 		}
1626 	} else {
1627 		sc->sc_r_hiwat = com_rbuf_hiwat;
1628 		sc->sc_r_lowat = com_rbuf_lowat;
1629 	}
1630 
1631 	mutex_spin_exit(&sc->sc_lock);
1632 
1633 	/*
1634 	 * Update the tty layer's idea of the carrier bit, in case we changed
1635 	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
1636 	 * explicit request.
1637 	 */
1638 	if (sc->sc_type == COM_TYPE_INGENIC) {
1639 		/* no DCD here */
1640 		(void) (*tp->t_linesw->l_modem)(tp, 1);
1641 	} else
1642 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, MSR_DCD));
1643 
1644 #ifdef COM_DEBUG
1645 	if (com_debug)
1646 		comstatus(sc, "comparam ");
1647 #endif
1648 
1649 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1650 		if (sc->sc_tx_stopped) {
1651 			sc->sc_tx_stopped = 0;
1652 			comstart(tp);
1653 		}
1654 	}
1655 
1656 	return (0);
1657 }
1658 
1659 void
1660 com_iflush(struct com_softc *sc)
1661 {
1662 	struct com_regs	*regsp = &sc->sc_regs;
1663 	uint8_t fifo;
1664 #ifdef DIAGNOSTIC
1665 	int reg;
1666 #endif
1667 	int timo;
1668 
1669 #ifdef DIAGNOSTIC
1670 	reg = 0xffff;
1671 #endif
1672 	timo = 50000;
1673 	/* flush any pending I/O */
1674 	while (ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)
1675 	    && --timo)
1676 #ifdef DIAGNOSTIC
1677 		reg =
1678 #else
1679 		    (void)
1680 #endif
1681 		    CSR_READ_1(regsp, COM_REG_RXDATA);
1682 #ifdef DIAGNOSTIC
1683 	if (!timo)
1684 		aprint_error_dev(sc->sc_dev, "com_iflush timeout %02x\n", reg);
1685 #endif
1686 
1687 	switch (sc->sc_type) {
1688 	case COM_TYPE_16750:
1689 	case COM_TYPE_DW_APB:
1690 		/*
1691 		 * Reset all Rx/Tx FIFO, preserve current FIFO length.
1692 		 * This should prevent triggering busy interrupt while
1693 		 * manipulating divisors.
1694 		 */
1695 		fifo = CSR_READ_1(regsp, COM_REG_FIFO) & (FIFO_TRIGGER_1 |
1696 		    FIFO_TRIGGER_4 | FIFO_TRIGGER_8 | FIFO_TRIGGER_14);
1697 		CSR_WRITE_1(regsp, COM_REG_FIFO,
1698 		    fifo | FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST);
1699 		delay(100);
1700 		break;
1701 	}
1702 }
1703 
1704 void
1705 com_loadchannelregs(struct com_softc *sc)
1706 {
1707 	struct com_regs *regsp = &sc->sc_regs;
1708 
1709 	/* XXXXX necessary? */
1710 	com_iflush(sc);
1711 
1712 	if (sc->sc_type == COM_TYPE_PXA2x0)
1713 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
1714 	else
1715 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
1716 
1717 	if (sc->sc_type == COM_TYPE_OMAP) {
1718 		/* disable before changing settings */
1719 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
1720 	}
1721 
1722 	if (ISSET(sc->sc_hwflags, COM_HW_FLOW)) {
1723 		KASSERT(sc->sc_type != COM_TYPE_AU1x00);
1724 		KASSERT(sc->sc_type != COM_TYPE_16550_NOERS);
1725 		/* no EFR on alchemy */
1726 		CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
1727 		CSR_WRITE_1(regsp, COM_REG_EFR, sc->sc_efr);
1728 	}
1729 	if (sc->sc_type == COM_TYPE_AU1x00) {
1730 		/* alchemy has single separate 16-bit clock divisor register */
1731 		CSR_WRITE_2(regsp, COM_REG_DLBL, sc->sc_dlbl +
1732 		    (sc->sc_dlbh << 8));
1733 	} else {
1734 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
1735 		CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
1736 		CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
1737 	}
1738 	CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
1739 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active = sc->sc_mcr);
1740 	CSR_WRITE_1(regsp, COM_REG_FIFO, sc->sc_fifo);
1741 	if (sc->sc_type == COM_TYPE_HAYESP) {
1742 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
1743 		    HAYESP_SETPRESCALER);
1744 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
1745 		    sc->sc_prescaler);
1746 	}
1747 	if (sc->sc_type == COM_TYPE_OMAP) {
1748 		/* setup the fifos.  the FCR value is not used as long
1749 		   as SCR[6] and SCR[7] are 0, which they are at reset
1750 		   and we never touch the SCR register */
1751 		uint8_t rx_fifo_trig = 40;
1752 		uint8_t tx_fifo_trig = 60;
1753 		uint8_t rx_start = 8;
1754 		uint8_t rx_halt = 60;
1755 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
1756 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
1757 
1758 		/* enable access to TCR & TLR */
1759 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr | MCR_TCR_TLR);
1760 
1761 		/* write tcr and tlr values */
1762 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
1763 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
1764 
1765 		/* disable access to TCR & TLR */
1766 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr);
1767 
1768 		/* enable again, but mode is based on speed */
1769 		if (sc->sc_tty->t_termios.c_ospeed > 230400) {
1770 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
1771 		} else {
1772 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
1773 		}
1774 	}
1775 
1776 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1777 }
1778 
1779 int
1780 comhwiflow(struct tty *tp, int block)
1781 {
1782 	struct com_softc *sc =
1783 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1784 
1785 	if (COM_ISALIVE(sc) == 0)
1786 		return (0);
1787 
1788 	if (sc->sc_mcr_rts == 0)
1789 		return (0);
1790 
1791 	mutex_spin_enter(&sc->sc_lock);
1792 
1793 	if (block) {
1794 		if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1795 			SET(sc->sc_rx_flags, RX_TTY_BLOCKED);
1796 			com_hwiflow(sc);
1797 		}
1798 	} else {
1799 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1800 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1801 			com_schedrx(sc);
1802 		}
1803 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1804 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED);
1805 			com_hwiflow(sc);
1806 		}
1807 	}
1808 
1809 	mutex_spin_exit(&sc->sc_lock);
1810 	return (1);
1811 }
1812 
1813 /*
1814  * (un)block input via hw flowcontrol
1815  */
1816 void
1817 com_hwiflow(struct com_softc *sc)
1818 {
1819 	struct com_regs *regsp= &sc->sc_regs;
1820 
1821 	if (sc->sc_mcr_rts == 0)
1822 		return;
1823 
1824 	if (ISSET(sc->sc_rx_flags, RX_ANY_BLOCK)) {
1825 		CLR(sc->sc_mcr, sc->sc_mcr_rts);
1826 		CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
1827 	} else {
1828 		SET(sc->sc_mcr, sc->sc_mcr_rts);
1829 		SET(sc->sc_mcr_active, sc->sc_mcr_rts);
1830 	}
1831 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active);
1832 }
1833 
1834 
1835 void
1836 comstart(struct tty *tp)
1837 {
1838 	struct com_softc *sc =
1839 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1840 	struct com_regs *regsp = &sc->sc_regs;
1841 	int s;
1842 
1843 	if (COM_ISALIVE(sc) == 0)
1844 		return;
1845 
1846 	s = spltty();
1847 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
1848 		goto out;
1849 	if (sc->sc_tx_stopped)
1850 		goto out;
1851 	if (!ttypull(tp))
1852 		goto out;
1853 
1854 	/* Grab the first contiguous region of buffer space. */
1855 	{
1856 		u_char *tba;
1857 		int tbc;
1858 
1859 		tba = tp->t_outq.c_cf;
1860 		tbc = ndqb(&tp->t_outq, 0);
1861 
1862 		mutex_spin_enter(&sc->sc_lock);
1863 
1864 		sc->sc_tba = tba;
1865 		sc->sc_tbc = tbc;
1866 	}
1867 
1868 	SET(tp->t_state, TS_BUSY);
1869 	sc->sc_tx_busy = 1;
1870 
1871 	/* Enable transmit completion interrupts if necessary. */
1872 	if (!ISSET(sc->sc_ier, IER_ETXRDY)) {
1873 		SET(sc->sc_ier, IER_ETXRDY);
1874 		CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1875 	}
1876 
1877 	/* Output the first chunk of the contiguous buffer. */
1878 	if (!ISSET(sc->sc_hwflags, COM_HW_NO_TXPRELOAD)) {
1879 		u_int n;
1880 
1881 		n = sc->sc_tbc;
1882 		if (n > sc->sc_fifolen)
1883 			n = sc->sc_fifolen;
1884 		CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
1885 		sc->sc_tbc -= n;
1886 		sc->sc_tba += n;
1887 	}
1888 
1889 	mutex_spin_exit(&sc->sc_lock);
1890 out:
1891 	splx(s);
1892 	return;
1893 }
1894 
1895 /*
1896  * Stop output on a line.
1897  */
1898 void
1899 comstop(struct tty *tp, int flag)
1900 {
1901 	struct com_softc *sc =
1902 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1903 
1904 	mutex_spin_enter(&sc->sc_lock);
1905 	if (ISSET(tp->t_state, TS_BUSY)) {
1906 		/* Stop transmitting at the next chunk. */
1907 		sc->sc_tbc = 0;
1908 		sc->sc_heldtbc = 0;
1909 		if (!ISSET(tp->t_state, TS_TTSTOP))
1910 			SET(tp->t_state, TS_FLUSH);
1911 	}
1912 	mutex_spin_exit(&sc->sc_lock);
1913 }
1914 
1915 void
1916 comdiag(void *arg)
1917 {
1918 	struct com_softc *sc = arg;
1919 	int overflows, floods;
1920 
1921 	mutex_spin_enter(&sc->sc_lock);
1922 	overflows = sc->sc_overflows;
1923 	sc->sc_overflows = 0;
1924 	floods = sc->sc_floods;
1925 	sc->sc_floods = 0;
1926 	sc->sc_errors = 0;
1927 	mutex_spin_exit(&sc->sc_lock);
1928 
1929 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
1930 	    device_xname(sc->sc_dev),
1931 	    overflows, overflows == 1 ? "" : "s",
1932 	    floods, floods == 1 ? "" : "s");
1933 }
1934 
1935 integrate void
1936 com_rxsoft(struct com_softc *sc, struct tty *tp)
1937 {
1938 	int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
1939 	u_char *get, *end;
1940 	u_int cc, scc;
1941 	u_char lsr;
1942 	int code;
1943 
1944 	end = sc->sc_ebuf;
1945 	get = sc->sc_rbget;
1946 	scc = cc = com_rbuf_size - sc->sc_rbavail;
1947 
1948 	if (cc == com_rbuf_size) {
1949 		sc->sc_floods++;
1950 		if (sc->sc_errors++ == 0)
1951 			callout_reset(&sc->sc_diag_callout, 60 * hz,
1952 			    comdiag, sc);
1953 	}
1954 
1955 	/* If not yet open, drop the entire buffer content here */
1956 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
1957 		get += cc << 1;
1958 		if (get >= end)
1959 			get -= com_rbuf_size << 1;
1960 		cc = 0;
1961 	}
1962 	while (cc) {
1963 		code = get[0];
1964 		lsr = get[1];
1965 		if (ISSET(lsr, LSR_OE | LSR_BI | LSR_FE | LSR_PE)) {
1966 			if (ISSET(lsr, LSR_OE)) {
1967 				sc->sc_overflows++;
1968 				if (sc->sc_errors++ == 0)
1969 					callout_reset(&sc->sc_diag_callout,
1970 					    60 * hz, comdiag, sc);
1971 			}
1972 			if (ISSET(lsr, LSR_BI | LSR_FE))
1973 				SET(code, TTY_FE);
1974 			if (ISSET(lsr, LSR_PE))
1975 				SET(code, TTY_PE);
1976 		}
1977 		if ((*rint)(code, tp) == -1) {
1978 			/*
1979 			 * The line discipline's buffer is out of space.
1980 			 */
1981 			if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1982 				/*
1983 				 * We're either not using flow control, or the
1984 				 * line discipline didn't tell us to block for
1985 				 * some reason.  Either way, we have no way to
1986 				 * know when there's more space available, so
1987 				 * just drop the rest of the data.
1988 				 */
1989 				get += cc << 1;
1990 				if (get >= end)
1991 					get -= com_rbuf_size << 1;
1992 				cc = 0;
1993 			} else {
1994 				/*
1995 				 * Don't schedule any more receive processing
1996 				 * until the line discipline tells us there's
1997 				 * space available (through comhwiflow()).
1998 				 * Leave the rest of the data in the input
1999 				 * buffer.
2000 				 */
2001 				SET(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
2002 			}
2003 			break;
2004 		}
2005 		get += 2;
2006 		if (get >= end)
2007 			get = sc->sc_rbuf;
2008 		cc--;
2009 	}
2010 
2011 	if (cc != scc) {
2012 		sc->sc_rbget = get;
2013 		mutex_spin_enter(&sc->sc_lock);
2014 
2015 		cc = sc->sc_rbavail += scc - cc;
2016 		/* Buffers should be ok again, release possible block. */
2017 		if (cc >= sc->sc_r_lowat) {
2018 			if (ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
2019 				CLR(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
2020 				SET(sc->sc_ier, IER_ERXRDY);
2021 				if (sc->sc_type == COM_TYPE_PXA2x0)
2022 					SET(sc->sc_ier, IER_ERXTOUT);
2023 				if (sc->sc_type == COM_TYPE_INGENIC ||
2024 				    sc->sc_type == COM_TYPE_TEGRA)
2025 					SET(sc->sc_ier, IER_ERXTOUT);
2026 
2027 				CSR_WRITE_1(&sc->sc_regs, COM_REG_IER,
2028 				    sc->sc_ier);
2029 			}
2030 			if (ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED)) {
2031 				CLR(sc->sc_rx_flags, RX_IBUF_BLOCKED);
2032 				com_hwiflow(sc);
2033 			}
2034 		}
2035 		mutex_spin_exit(&sc->sc_lock);
2036 	}
2037 }
2038 
2039 integrate void
2040 com_txsoft(struct com_softc *sc, struct tty *tp)
2041 {
2042 
2043 	CLR(tp->t_state, TS_BUSY);
2044 	if (ISSET(tp->t_state, TS_FLUSH))
2045 		CLR(tp->t_state, TS_FLUSH);
2046 	else
2047 		ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
2048 	(*tp->t_linesw->l_start)(tp);
2049 }
2050 
2051 integrate void
2052 com_stsoft(struct com_softc *sc, struct tty *tp)
2053 {
2054 	u_char msr, delta;
2055 
2056 	mutex_spin_enter(&sc->sc_lock);
2057 	msr = sc->sc_msr;
2058 	delta = sc->sc_msr_delta;
2059 	sc->sc_msr_delta = 0;
2060 	mutex_spin_exit(&sc->sc_lock);
2061 
2062 	if (ISSET(delta, sc->sc_msr_dcd)) {
2063 		/*
2064 		 * Inform the tty layer that carrier detect changed.
2065 		 */
2066 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(msr, MSR_DCD));
2067 	}
2068 
2069 	if (ISSET(delta, sc->sc_msr_cts)) {
2070 		/* Block or unblock output according to flow control. */
2071 		if (ISSET(msr, sc->sc_msr_cts)) {
2072 			sc->sc_tx_stopped = 0;
2073 			(*tp->t_linesw->l_start)(tp);
2074 		} else {
2075 			sc->sc_tx_stopped = 1;
2076 		}
2077 	}
2078 
2079 #ifdef COM_DEBUG
2080 	if (com_debug)
2081 		comstatus(sc, "com_stsoft");
2082 #endif
2083 }
2084 
2085 void
2086 comsoft(void *arg)
2087 {
2088 	struct com_softc *sc = arg;
2089 	struct tty *tp;
2090 
2091 	if (COM_ISALIVE(sc) == 0)
2092 		return;
2093 
2094 	tp = sc->sc_tty;
2095 
2096 	if (sc->sc_rx_ready) {
2097 		sc->sc_rx_ready = 0;
2098 		com_rxsoft(sc, tp);
2099 	}
2100 
2101 	if (sc->sc_st_check) {
2102 		sc->sc_st_check = 0;
2103 		com_stsoft(sc, tp);
2104 	}
2105 
2106 	if (sc->sc_tx_done) {
2107 		sc->sc_tx_done = 0;
2108 		com_txsoft(sc, tp);
2109 	}
2110 }
2111 
2112 int
2113 comintr(void *arg)
2114 {
2115 	struct com_softc *sc = arg;
2116 	struct com_regs *regsp = &sc->sc_regs;
2117 
2118 	u_char *put, *end;
2119 	u_int cc;
2120 	u_char lsr, iir;
2121 
2122 	if (COM_ISALIVE(sc) == 0)
2123 		return (0);
2124 
2125 	KASSERT(regsp != NULL);
2126 
2127 	mutex_spin_enter(&sc->sc_lock);
2128 	iir = CSR_READ_1(regsp, COM_REG_IIR);
2129 
2130 	/* Handle ns16750-specific busy interrupt. */
2131 	if (sc->sc_type == COM_TYPE_16750 &&
2132 	    (iir & IIR_BUSY) == IIR_BUSY) {
2133 		for (int timeout = 10000;
2134 		    (CSR_READ_1(regsp, COM_REG_USR) & 0x1) != 0; timeout--)
2135 			if (timeout <= 0) {
2136 				aprint_error_dev(sc->sc_dev,
2137 				    "timeout while waiting for BUSY interrupt "
2138 				    "acknowledge\n");
2139 				mutex_spin_exit(&sc->sc_lock);
2140 				return (0);
2141 			}
2142 
2143 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2144 		iir = CSR_READ_1(regsp, COM_REG_IIR);
2145 	}
2146 
2147 	/* DesignWare APB UART BUSY interrupt */
2148 	if (sc->sc_type == COM_TYPE_DW_APB &&
2149 	    (iir & IIR_BUSY) == IIR_BUSY) {
2150 		if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
2151 			(void)CSR_READ_1(regsp, COM_REG_USR);
2152 		} else if ((CSR_READ_1(regsp, COM_REG_USR) & 0x1) != 0) {
2153 			CSR_WRITE_1(regsp, COM_REG_HALT, HALT_CHCFG_EN);
2154 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
2155 			CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
2156 			CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
2157 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2158 			CSR_WRITE_1(regsp, COM_REG_HALT,
2159 			    HALT_CHCFG_EN | HALT_CHCFG_UD);
2160 			for (int timeout = 10000000;
2161 			    (CSR_READ_1(regsp, COM_REG_HALT) & HALT_CHCFG_UD) != 0;
2162 			    timeout--) {
2163 				if (timeout <= 0) {
2164 					aprint_error_dev(sc->sc_dev,
2165 					    "timeout while waiting for HALT "
2166 					    "update acknowledge 0x%x 0x%x\n",
2167 					    CSR_READ_1(regsp, COM_REG_HALT),
2168 					    CSR_READ_1(regsp, COM_REG_USR));
2169 					break;
2170 				}
2171 			}
2172 			CSR_WRITE_1(regsp, COM_REG_HALT, 0);
2173 			(void)CSR_READ_1(regsp, COM_REG_USR);
2174 		} else {
2175 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
2176 			CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
2177 			CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
2178 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2179 		}
2180 	}
2181 
2182 	end = sc->sc_ebuf;
2183 	put = sc->sc_rbput;
2184 	cc = sc->sc_rbavail;
2185 
2186 	if (ISSET(iir, IIR_NOPEND)) {
2187 		if (ISSET(sc->sc_hwflags, COM_HW_BROKEN_ETXRDY))
2188 			goto do_tx;
2189 		mutex_spin_exit(&sc->sc_lock);
2190 		return (0);
2191 	}
2192 
2193 again:	do {
2194 		u_char	msr, delta;
2195 
2196 		lsr = CSR_READ_1(regsp, COM_REG_LSR);
2197 		if (ISSET(lsr, LSR_BI)) {
2198 			int cn_trapped = 0; /* see above: cn_trap() */
2199 
2200 			cn_check_magic(sc->sc_tty->t_dev,
2201 				       CNC_BREAK, com_cnm_state);
2202 			if (cn_trapped)
2203 				continue;
2204 #if defined(KGDB) && !defined(DDB)
2205 			if (ISSET(sc->sc_hwflags, COM_HW_KGDB)) {
2206 				kgdb_connect(1);
2207 				continue;
2208 			}
2209 #endif
2210 		}
2211 
2212 		if (sc->sc_type == COM_TYPE_BCMAUXUART && ISSET(iir, IIR_RXRDY))
2213 			lsr |= LSR_RXRDY;
2214 
2215 		if (ISSET(lsr, LSR_RCV_MASK) &&
2216 		    !ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
2217 			while (cc > 0) {
2218 				int cn_trapped = 0;
2219 				put[0] = CSR_READ_1(regsp, COM_REG_RXDATA);
2220 				put[1] = lsr;
2221 				cn_check_magic(sc->sc_tty->t_dev,
2222 					       put[0], com_cnm_state);
2223 				if (cn_trapped)
2224 					goto next;
2225 				put += 2;
2226 				if (put >= end)
2227 					put = sc->sc_rbuf;
2228 				cc--;
2229 			next:
2230 				lsr = CSR_READ_1(regsp, COM_REG_LSR);
2231 				if (!ISSET(lsr, LSR_RCV_MASK))
2232 					break;
2233 			}
2234 
2235 			/*
2236 			 * Current string of incoming characters ended because
2237 			 * no more data was available or we ran out of space.
2238 			 * Schedule a receive event if any data was received.
2239 			 * If we're out of space, turn off receive interrupts.
2240 			 */
2241 			sc->sc_rbput = put;
2242 			sc->sc_rbavail = cc;
2243 			if (!ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED))
2244 				sc->sc_rx_ready = 1;
2245 
2246 			/*
2247 			 * See if we are in danger of overflowing a buffer. If
2248 			 * so, use hardware flow control to ease the pressure.
2249 			 */
2250 			if (!ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED) &&
2251 			    cc < sc->sc_r_hiwat) {
2252 				SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
2253 				com_hwiflow(sc);
2254 			}
2255 
2256 			/*
2257 			 * If we're out of space, disable receive interrupts
2258 			 * until the queue has drained a bit.
2259 			 */
2260 			if (!cc) {
2261 				SET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
2262 				switch (sc->sc_type) {
2263 				case COM_TYPE_PXA2x0:
2264 					CLR(sc->sc_ier, IER_ERXRDY|IER_ERXTOUT);
2265 					break;
2266 				case COM_TYPE_INGENIC:
2267 				case COM_TYPE_TEGRA:
2268 					CLR(sc->sc_ier,
2269 					    IER_ERXRDY | IER_ERXTOUT);
2270 					break;
2271 				default:
2272 					CLR(sc->sc_ier, IER_ERXRDY);
2273 					break;
2274 				}
2275 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
2276 			}
2277 		} else {
2278 			if ((iir & (IIR_RXRDY|IIR_TXRDY)) == IIR_RXRDY) {
2279 				(void) CSR_READ_1(regsp, COM_REG_RXDATA);
2280 				continue;
2281 			}
2282 		}
2283 
2284 		msr = CSR_READ_1(regsp, COM_REG_MSR);
2285 		delta = msr ^ sc->sc_msr;
2286 		sc->sc_msr = msr;
2287 		if ((sc->sc_pps_state.ppsparam.mode & PPS_CAPTUREBOTH) &&
2288 		    (delta & MSR_DCD)) {
2289 			mutex_spin_enter(&timecounter_lock);
2290 			pps_capture(&sc->sc_pps_state);
2291 			pps_event(&sc->sc_pps_state,
2292 			    (msr & MSR_DCD) ?
2293 			    PPS_CAPTUREASSERT :
2294 			    PPS_CAPTURECLEAR);
2295 			mutex_spin_exit(&timecounter_lock);
2296 		}
2297 
2298 		/*
2299 		 * Process normal status changes
2300 		 */
2301 		if (ISSET(delta, sc->sc_msr_mask)) {
2302 			SET(sc->sc_msr_delta, delta);
2303 
2304 			/*
2305 			 * Stop output immediately if we lose the output
2306 			 * flow control signal or carrier detect.
2307 			 */
2308 			if (ISSET(~msr, sc->sc_msr_mask)) {
2309 				sc->sc_tbc = 0;
2310 				sc->sc_heldtbc = 0;
2311 #ifdef COM_DEBUG
2312 				if (com_debug)
2313 					comstatus(sc, "comintr  ");
2314 #endif
2315 			}
2316 
2317 			sc->sc_st_check = 1;
2318 		}
2319 	} while (!ISSET((iir =
2320 	    CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND) &&
2321 	    /*
2322 	     * Since some device (e.g., ST16C1550) doesn't clear IIR_TXRDY
2323 	     * by IIR read, so we can't do this way: `process all interrupts,
2324 	     * then do TX if possible'.
2325 	     */
2326 	    (iir & IIR_IMASK) != IIR_TXRDY);
2327 
2328 do_tx:
2329 	/*
2330 	 * Read LSR again, since there may be an interrupt between
2331 	 * the last LSR read and IIR read above.
2332 	 */
2333 	lsr = CSR_READ_1(regsp, COM_REG_LSR);
2334 
2335 	/*
2336 	 * See if data can be transmitted as well.
2337 	 * Schedule tx done event if no data left
2338 	 * and tty was marked busy.
2339 	 */
2340 	if (ISSET(lsr, LSR_TXRDY)) {
2341 		/*
2342 		 * If we've delayed a parameter change, do it now, and restart
2343 		 * output.
2344 		 */
2345 		if (sc->sc_heldchange) {
2346 			com_loadchannelregs(sc);
2347 			sc->sc_heldchange = 0;
2348 			sc->sc_tbc = sc->sc_heldtbc;
2349 			sc->sc_heldtbc = 0;
2350 		}
2351 
2352 		/* Output the next chunk of the contiguous buffer, if any. */
2353 		if (sc->sc_tbc > 0) {
2354 			u_int n;
2355 
2356 			n = sc->sc_tbc;
2357 			if (n > sc->sc_fifolen)
2358 				n = sc->sc_fifolen;
2359 			CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
2360 			sc->sc_tbc -= n;
2361 			sc->sc_tba += n;
2362 		} else {
2363 			/* Disable transmit completion interrupts if necessary. */
2364 			if (ISSET(sc->sc_ier, IER_ETXRDY)) {
2365 				CLR(sc->sc_ier, IER_ETXRDY);
2366 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
2367 			}
2368 			if (sc->sc_tx_busy) {
2369 				sc->sc_tx_busy = 0;
2370 				sc->sc_tx_done = 1;
2371 			}
2372 		}
2373 	}
2374 
2375 	if (!ISSET((iir = CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND))
2376 		goto again;
2377 
2378 	mutex_spin_exit(&sc->sc_lock);
2379 
2380 	/* Wake up the poller. */
2381 	if ((sc->sc_rx_ready | sc->sc_st_check | sc->sc_tx_done) != 0)
2382 		softint_schedule(sc->sc_si);
2383 
2384 #ifdef RND_COM
2385 	rnd_add_uint32(&sc->rnd_source, iir | lsr);
2386 #endif
2387 
2388 	return (1);
2389 }
2390 
2391 /*
2392  * The following functions are polled getc and putc routines, shared
2393  * by the console and kgdb glue.
2394  *
2395  * The read-ahead code is so that you can detect pending in-band
2396  * cn_magic in polled mode while doing output rather than having to
2397  * wait until the kernel decides it needs input.
2398  */
2399 
2400 #define MAX_READAHEAD	20
2401 static int com_readahead[MAX_READAHEAD];
2402 static int com_readaheadcount = 0;
2403 
2404 int
2405 com_common_getc(dev_t dev, struct com_regs *regsp)
2406 {
2407 	int s = splserial();
2408 	u_char stat, c;
2409 
2410 	/* got a character from reading things earlier */
2411 	if (com_readaheadcount > 0) {
2412 		int i;
2413 
2414 		c = com_readahead[0];
2415 		for (i = 1; i < com_readaheadcount; i++) {
2416 			com_readahead[i-1] = com_readahead[i];
2417 		}
2418 		com_readaheadcount--;
2419 		splx(s);
2420 		return (c);
2421 	}
2422 
2423 	/* don't block until a character becomes available */
2424 	if (!ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
2425 		splx(s);
2426 		return -1;
2427 	}
2428 
2429 	c = CSR_READ_1(regsp, COM_REG_RXDATA);
2430 	stat = CSR_READ_1(regsp, COM_REG_IIR);
2431 	{
2432 		int cn_trapped = 0;	/* required by cn_trap, see above */
2433 #ifdef DDB
2434 		extern int db_active;
2435 		if (!db_active)
2436 #endif
2437 			cn_check_magic(dev, c, com_cnm_state);
2438 	}
2439 	splx(s);
2440 	return (c);
2441 }
2442 
2443 static void
2444 com_common_putc(dev_t dev, struct com_regs *regsp, int c, int with_readahead)
2445 {
2446 	int s = splserial();
2447 	int cin, stat, timo;
2448 
2449 	if (with_readahead && com_readaheadcount < MAX_READAHEAD
2450 	     && ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
2451 		int cn_trapped = 0;
2452 		cin = CSR_READ_1(regsp, COM_REG_RXDATA);
2453 		stat = CSR_READ_1(regsp, COM_REG_IIR);
2454 		cn_check_magic(dev, cin, com_cnm_state);
2455 		com_readahead[com_readaheadcount++] = cin;
2456 	}
2457 
2458 	/* wait for any pending transmission to finish */
2459 	timo = 150000;
2460 	while (!ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_TXRDY) && --timo)
2461 		continue;
2462 
2463 	CSR_WRITE_1(regsp, COM_REG_TXDATA, c);
2464 	COM_BARRIER(regsp, BR | BW);
2465 
2466 	splx(s);
2467 }
2468 
2469 /*
2470  * Initialize UART for use as console or KGDB line.
2471  */
2472 int
2473 cominit(struct com_regs *regsp, int rate, int frequency, int type,
2474     tcflag_t cflag)
2475 {
2476 
2477 	if (bus_space_map(regsp->cr_iot, regsp->cr_iobase, regsp->cr_nports, 0,
2478 		&regsp->cr_ioh))
2479 		return (ENOMEM); /* ??? */
2480 
2481 	if (type == COM_TYPE_OMAP) {
2482 		/* disable before changing settings */
2483 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
2484 	}
2485 
2486 	rate = comspeed(rate, frequency, type);
2487 	if (rate != -1) {
2488 		if (type == COM_TYPE_AU1x00) {
2489 			/* no EFR on alchemy */
2490 			CSR_WRITE_2(regsp, COM_REG_DLBL, rate);
2491 		} else {
2492 			if ((type != COM_TYPE_16550_NOERS) &&
2493 			    (type != COM_TYPE_INGENIC)) {
2494 				CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
2495 				CSR_WRITE_1(regsp, COM_REG_EFR, 0);
2496 			}
2497 			CSR_WRITE_1(regsp, COM_REG_LCR, LCR_DLAB);
2498 			CSR_WRITE_1(regsp, COM_REG_DLBL, rate & 0xff);
2499 			CSR_WRITE_1(regsp, COM_REG_DLBH, rate >> 8);
2500 		}
2501 	}
2502 	CSR_WRITE_1(regsp, COM_REG_LCR, cflag2lcr(cflag));
2503 	CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2504 
2505 	if (type == COM_TYPE_INGENIC) {
2506 		CSR_WRITE_1(regsp, COM_REG_FIFO,
2507 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
2508 		    FIFO_TRIGGER_1 | FIFO_UART_ON);
2509 	} else {
2510 		CSR_WRITE_1(regsp, COM_REG_FIFO,
2511 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
2512 		    FIFO_TRIGGER_1);
2513 	}
2514 
2515 	if (type == COM_TYPE_OMAP) {
2516 		/* setup the fifos.  the FCR value is not used as long
2517 		   as SCR[6] and SCR[7] are 0, which they are at reset
2518 		   and we never touch the SCR register */
2519 		uint8_t rx_fifo_trig = 40;
2520 		uint8_t tx_fifo_trig = 60;
2521 		uint8_t rx_start = 8;
2522 		uint8_t rx_halt = 60;
2523 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
2524 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
2525 
2526 		/* enable access to TCR & TLR */
2527 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS | MCR_TCR_TLR);
2528 
2529 		/* write tcr and tlr values */
2530 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
2531 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
2532 
2533 		/* disable access to TCR & TLR */
2534 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2535 
2536 		/* enable again, but mode is based on speed */
2537 		if (rate > 230400) {
2538 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
2539 		} else {
2540 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
2541 		}
2542 	}
2543 
2544 	if (type == COM_TYPE_PXA2x0)
2545 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
2546 	else
2547 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
2548 
2549 	return (0);
2550 }
2551 
2552 int
2553 comcnattach1(struct com_regs *regsp, int rate, int frequency, int type,
2554     tcflag_t cflag)
2555 {
2556 	int res;
2557 
2558 	comcons_info.regs = *regsp;
2559 
2560 	res = cominit(&comcons_info.regs, rate, frequency, type, cflag);
2561 	if (res)
2562 		return (res);
2563 
2564 	cn_tab = &comcons;
2565 	cn_init_magic(&com_cnm_state);
2566 	cn_set_magic("\047\001"); /* default magic is BREAK */
2567 
2568 	comcons_info.frequency = frequency;
2569 	comcons_info.type = type;
2570 	comcons_info.rate = rate;
2571 	comcons_info.cflag = cflag;
2572 
2573 	return (0);
2574 }
2575 
2576 int
2577 comcnattach(bus_space_tag_t iot, bus_addr_t iobase, int rate, int frequency,
2578     int type, tcflag_t cflag)
2579 {
2580 	struct com_regs	regs;
2581 
2582 	/*XXX*/
2583 	bus_space_handle_t dummy_bsh;
2584 	memset(&dummy_bsh, 0, sizeof(dummy_bsh));
2585 
2586 	/*
2587 	 * dummy_bsh required because com_init_regs() wants it.  A
2588 	 * real bus_space_handle will be filled in by cominit() later.
2589 	 * XXXJRT Detangle this mess eventually, plz.
2590 	 */
2591 	com_init_regs(&regs, iot, dummy_bsh/*XXX*/, iobase);
2592 
2593 	return comcnattach1(&regs, rate, frequency, type, cflag);
2594 }
2595 
2596 static int
2597 comcnreattach(void)
2598 {
2599 	return comcnattach1(&comcons_info.regs, comcons_info.rate,
2600 	    comcons_info.frequency, comcons_info.type, comcons_info.cflag);
2601 }
2602 
2603 int
2604 comcngetc(dev_t dev)
2605 {
2606 
2607 	return (com_common_getc(dev, &comcons_info.regs));
2608 }
2609 
2610 /*
2611  * Console kernel output character routine.
2612  */
2613 void
2614 comcnputc(dev_t dev, int c)
2615 {
2616 
2617 	com_common_putc(dev, &comcons_info.regs, c, cold);
2618 }
2619 
2620 void
2621 comcnpollc(dev_t dev, int on)
2622 {
2623 
2624 	com_readaheadcount = 0;
2625 }
2626 
2627 #ifdef KGDB
2628 int
2629 com_kgdb_attach1(struct com_regs *regsp, int rate, int frequency, int type,
2630     tcflag_t cflag)
2631 {
2632 	int res;
2633 
2634 	if (bus_space_is_equal(regsp->cr_iot, comcons_info.regs.cr_iot) &&
2635 	    regsp->cr_iobase == comcons_info.regs.cr_iobase) {
2636 #if !defined(DDB)
2637 		return (EBUSY); /* cannot share with console */
2638 #else
2639 		comkgdbregs = *regsp;
2640 		comkgdbregs.cr_ioh = comcons_info.regs.cr_ioh;
2641 #endif
2642 	} else {
2643 		comkgdbregs = *regsp;
2644 		res = cominit(&comkgdbregs, rate, frequency, type, cflag);
2645 		if (res)
2646 			return (res);
2647 
2648 		/*
2649 		 * XXXfvdl this shouldn't be needed, but the cn_magic goo
2650 		 * expects this to be initialized
2651 		 */
2652 		cn_init_magic(&com_cnm_state);
2653 		cn_set_magic("\047\001");
2654 	}
2655 
2656 	kgdb_attach(com_kgdb_getc, com_kgdb_putc, NULL);
2657 	kgdb_dev = 123; /* unneeded, only to satisfy some tests */
2658 
2659 	return (0);
2660 }
2661 
2662 int
2663 com_kgdb_attach(bus_space_tag_t iot, bus_addr_t iobase, int rate,
2664     int frequency, int type, tcflag_t cflag)
2665 {
2666 	struct com_regs regs;
2667 
2668 	com_init_regs(&regs, iot, (bus_space_handle_t)0/*XXX*/, iobase);
2669 
2670 	return com_kgdb_attach1(&regs, rate, frequency, type, cflag);
2671 }
2672 
2673 /* ARGSUSED */
2674 int
2675 com_kgdb_getc(void *arg)
2676 {
2677 
2678 	return (com_common_getc(NODEV, &comkgdbregs));
2679 }
2680 
2681 /* ARGSUSED */
2682 void
2683 com_kgdb_putc(void *arg, int c)
2684 {
2685 
2686 	com_common_putc(NODEV, &comkgdbregs, c, 0);
2687 }
2688 #endif /* KGDB */
2689 
2690 /* helper function to identify the com ports used by
2691  console or KGDB (and not yet autoconf attached) */
2692 int
2693 com_is_console(bus_space_tag_t iot, bus_addr_t iobase, bus_space_handle_t *ioh)
2694 {
2695 	bus_space_handle_t help;
2696 
2697 	if (!comconsattached &&
2698 	    bus_space_is_equal(iot, comcons_info.regs.cr_iot) &&
2699 	    iobase == comcons_info.regs.cr_iobase)
2700 		help = comcons_info.regs.cr_ioh;
2701 #ifdef KGDB
2702 	else if (!com_kgdb_attached &&
2703 	    bus_space_is_equal(iot, comkgdbregs.cr_iot) &&
2704 	    iobase == comkgdbregs.cr_iobase)
2705 		help = comkgdbregs.cr_ioh;
2706 #endif
2707 	else
2708 		return (0);
2709 
2710 	if (ioh)
2711 		*ioh = help;
2712 	return (1);
2713 }
2714 
2715 /*
2716  * this routine exists to serve as a shutdown hook for systems that
2717  * have firmware which doesn't interact properly with a com device in
2718  * FIFO mode.
2719  */
2720 bool
2721 com_cleanup(device_t self, int how)
2722 {
2723 	struct com_softc *sc = device_private(self);
2724 
2725 	if (ISSET(sc->sc_hwflags, COM_HW_FIFO))
2726 		CSR_WRITE_1(&sc->sc_regs, COM_REG_FIFO, 0);
2727 
2728 	return true;
2729 }
2730 
2731 bool
2732 com_suspend(device_t self, const pmf_qual_t *qual)
2733 {
2734 	struct com_softc *sc = device_private(self);
2735 
2736 #if 0
2737 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE) && cn_tab == &comcons)
2738 		cn_tab = &comcons_suspend;
2739 #endif
2740 
2741 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, 0);
2742 	(void)CSR_READ_1(&sc->sc_regs, COM_REG_IIR);
2743 
2744 	return true;
2745 }
2746 
2747 bool
2748 com_resume(device_t self, const pmf_qual_t *qual)
2749 {
2750 	struct com_softc *sc = device_private(self);
2751 
2752 	mutex_spin_enter(&sc->sc_lock);
2753 	com_loadchannelregs(sc);
2754 	mutex_spin_exit(&sc->sc_lock);
2755 
2756 	return true;
2757 }
2758