xref: /netbsd-src/sys/dev/ic/com.c (revision f3cfa6f6ce31685c6c4a758bc430e69eb99f50a4)
1 /* $NetBSD: com.c,v 1.355 2019/01/11 23:10:40 thorpej 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 1.355 2019/01/11 23:10:40 thorpej 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);
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 	NULL, NULL, comcngetc, comcnputc, comcnpollc, NULL, NULL, NULL,
196 	NODEV, CN_NORMAL
197 };
198 
199 
200 const struct cdevsw com_cdevsw = {
201 	.d_open = comopen,
202 	.d_close = comclose,
203 	.d_read = comread,
204 	.d_write = comwrite,
205 	.d_ioctl = comioctl,
206 	.d_stop = comstop,
207 	.d_tty = comtty,
208 	.d_poll = compoll,
209 	.d_mmap = nommap,
210 	.d_kqfilter = ttykqfilter,
211 	.d_discard = nodiscard,
212 	.d_flag = D_TTY
213 };
214 
215 /*
216  * Make this an option variable one can patch.
217  * But be warned:  this must be a power of 2!
218  */
219 u_int com_rbuf_size = COM_RING_SIZE;
220 
221 /* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
222 u_int com_rbuf_hiwat = (COM_RING_SIZE * 1) / 4;
223 u_int com_rbuf_lowat = (COM_RING_SIZE * 3) / 4;
224 
225 static int comconsattached;
226 static struct cnm_state com_cnm_state;
227 
228 #ifdef KGDB
229 #include <sys/kgdb.h>
230 
231 static struct com_regs comkgdbregs;
232 static int com_kgdb_attached;
233 
234 int	com_kgdb_getc(void *);
235 void	com_kgdb_putc(void *, int);
236 #endif /* KGDB */
237 
238 /* initializer for typical 16550-ish hardware */
239 static const bus_size_t com_std_map[COM_REGMAP_NENTRIES] = {
240 	[COM_REG_RXDATA]	=	com_data,
241 	[COM_REG_TXDATA]	=	com_data,
242 	[COM_REG_DLBL]		=	com_dlbl,
243 	[COM_REG_DLBH]		=	com_dlbh,
244 	[COM_REG_IER]		=	com_ier,
245 	[COM_REG_IIR]		=	com_iir,
246 	[COM_REG_FIFO]		=	com_fifo,
247 	[COM_REG_TCR]		=	com_fifo,
248 	[COM_REG_EFR]		=	com_efr,
249 	[COM_REG_TLR]		=	com_efr,
250 	[COM_REG_LCR]		=	com_lcr,
251 	[COM_REG_MCR]		=	com_mcr,
252 	[COM_REG_LSR]		=	com_lsr,
253 	[COM_REG_MSR]		=	com_msr,
254 	[COM_REG_USR]		=	com_usr,
255 	[COM_REG_TFL]		=	com_tfl,
256 	[COM_REG_RFL]		=	com_rfl,
257 	[COM_REG_HALT]		=	com_halt,
258 	[COM_REG_MDR1]		=	com_mdr1,
259 };
260 
261 #define	COMDIALOUT_MASK	TTDIALOUT_MASK
262 
263 #define	COMUNIT(x)	TTUNIT(x)
264 #define	COMDIALOUT(x)	TTDIALOUT(x)
265 
266 #define	COM_ISALIVE(sc)	((sc)->enabled != 0 && \
267 			 device_is_active((sc)->sc_dev))
268 
269 #define	BR	BUS_SPACE_BARRIER_READ
270 #define	BW	BUS_SPACE_BARRIER_WRITE
271 #define COM_BARRIER(r, f) \
272 	bus_space_barrier((r)->cr_iot, (r)->cr_ioh, 0, (r)->cr_nports, (f))
273 
274 /*
275  * com_init_regs --
276  *	Driver front-ends use this to initialize our register map
277  *	in the standard fashion.  They may then tailor the map to
278  *	their own particular requirements.
279  */
280 void
281 com_init_regs(struct com_regs *regs, bus_space_tag_t st, bus_space_handle_t sh,
282 	      bus_addr_t addr)
283 {
284 
285 	memset(regs, 0, sizeof(*regs));
286 	regs->cr_iot = st;
287 	regs->cr_ioh = sh;
288 	regs->cr_iobase = addr;
289 	regs->cr_nports = COM_NPORTS;
290 	memcpy(regs->cr_map, com_std_map, sizeof(regs->cr_map));
291 }
292 
293 /*
294  * com_init_regs_stride --
295  *	Convenience function for front-ends that have a stride between
296  *	registers.
297  */
298 void
299 com_init_regs_stride(struct com_regs *regs, bus_space_tag_t st,
300 		     bus_space_handle_t sh, bus_addr_t addr, u_int regshift)
301 {
302 
303 	com_init_regs(regs, st, sh, addr);
304 	for (size_t i = 0; i < __arraycount(regs->cr_map); i++) {
305 		regs->cr_map[i] <<= regshift;
306 	}
307 	regs->cr_nports <<= regshift;
308 }
309 
310 /*ARGSUSED*/
311 int
312 comspeed(long speed, long frequency, int type)
313 {
314 #define	divrnd(n, q)	(((n)*2/(q)+1)/2)	/* divide and round off */
315 
316 	int x, err;
317 	int divisor = 16;
318 
319 	if ((type == COM_TYPE_OMAP) && (speed > 230400)) {
320 	    divisor = 13;
321 	}
322 
323 	if (speed == 0)
324 		return (0);
325 	if (speed < 0)
326 		return (-1);
327 	x = divrnd(frequency / divisor, speed);
328 	if (x <= 0)
329 		return (-1);
330 	err = divrnd(((quad_t)frequency) * 1000 / divisor, speed * x) - 1000;
331 	if (err < 0)
332 		err = -err;
333 	if (err > COM_TOLERANCE)
334 		return (-1);
335 	return (x);
336 
337 #undef	divrnd
338 }
339 
340 #ifdef COM_DEBUG
341 int	com_debug = 0;
342 
343 void comstatus(struct com_softc *, const char *);
344 void
345 comstatus(struct com_softc *sc, const char *str)
346 {
347 	struct tty *tp = sc->sc_tty;
348 
349 	aprint_normal_dev(sc->sc_dev,
350 	    "%s %cclocal  %cdcd %cts_carr_on %cdtr %ctx_stopped\n",
351 	    str,
352 	    ISSET(tp->t_cflag, CLOCAL) ? '+' : '-',
353 	    ISSET(sc->sc_msr, MSR_DCD) ? '+' : '-',
354 	    ISSET(tp->t_state, TS_CARR_ON) ? '+' : '-',
355 	    ISSET(sc->sc_mcr, MCR_DTR) ? '+' : '-',
356 	    sc->sc_tx_stopped ? '+' : '-');
357 
358 	aprint_normal_dev(sc->sc_dev,
359 	    "%s %ccrtscts %ccts %cts_ttstop  %crts rx_flags=0x%x\n",
360 	    str,
361 	    ISSET(tp->t_cflag, CRTSCTS) ? '+' : '-',
362 	    ISSET(sc->sc_msr, MSR_CTS) ? '+' : '-',
363 	    ISSET(tp->t_state, TS_TTSTOP) ? '+' : '-',
364 	    ISSET(sc->sc_mcr, MCR_RTS) ? '+' : '-',
365 	    sc->sc_rx_flags);
366 }
367 #endif
368 
369 int
370 com_probe_subr(struct com_regs *regs)
371 {
372 
373 	/* force access to id reg */
374 	CSR_WRITE_1(regs, COM_REG_LCR, LCR_8BITS);
375 	CSR_WRITE_1(regs, COM_REG_IIR, 0);
376 	if ((CSR_READ_1(regs, COM_REG_LCR) != LCR_8BITS) ||
377 	    (CSR_READ_1(regs, COM_REG_IIR) & 0x38))
378 		return (0);
379 
380 	return (1);
381 }
382 
383 int
384 comprobe1(bus_space_tag_t iot, bus_space_handle_t ioh)
385 {
386 	struct com_regs	regs;
387 
388 	com_init_regs(&regs, iot, ioh, 0/*XXX*/);
389 
390 	return com_probe_subr(&regs);
391 }
392 
393 /*
394  * No locking in this routine; it is only called during attach,
395  * or with the port already locked.
396  */
397 static void
398 com_enable_debugport(struct com_softc *sc)
399 {
400 
401 	/* Turn on line break interrupt, set carrier. */
402 	sc->sc_ier = IER_ERLS;
403 	if (sc->sc_type == COM_TYPE_PXA2x0)
404 		sc->sc_ier |= IER_EUART | IER_ERXTOUT;
405 	if (sc->sc_type == COM_TYPE_INGENIC ||
406 	    sc->sc_type == COM_TYPE_TEGRA)
407 		sc->sc_ier |= IER_ERXTOUT;
408 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
409 	SET(sc->sc_mcr, MCR_DTR | MCR_RTS);
410 	CSR_WRITE_1(&sc->sc_regs, COM_REG_MCR, sc->sc_mcr);
411 }
412 
413 static void
414 com_intr_poll(void *arg)
415 {
416 	struct com_softc * const sc = arg;
417 
418 	comintr(sc);
419 
420 	callout_schedule(&sc->sc_poll_callout, 1);
421 }
422 
423 void
424 com_attach_subr(struct com_softc *sc)
425 {
426 	struct com_regs *regsp = &sc->sc_regs;
427 	struct tty *tp;
428 	u_int8_t lcr;
429 	const char *fifo_msg = NULL;
430 	prop_dictionary_t	dict;
431 	bool is_console = true;
432 	bool force_console = false;
433 
434 	aprint_naive("\n");
435 
436 	dict = device_properties(sc->sc_dev);
437 	prop_dictionary_get_bool(dict, "is_console", &is_console);
438 	prop_dictionary_get_bool(dict, "force_console", &force_console);
439 	callout_init(&sc->sc_diag_callout, 0);
440 	callout_init(&sc->sc_poll_callout, 0);
441 	callout_setfunc(&sc->sc_poll_callout, com_intr_poll, sc);
442 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_HIGH);
443 
444 #if defined(COM_16650)
445 	sc->sc_type = COM_TYPE_16650;
446 #elif defined(COM_16750)
447 	sc->sc_type = COM_TYPE_16750;
448 #elif defined(COM_HAYESP)
449 	sc->sc_type = COM_TYPE_HAYESP;
450 #elif defined(COM_PXA2X0)
451 	sc->sc_type = COM_TYPE_PXA2x0;
452 #endif
453 
454 	/* Disable interrupts before configuring the device. */
455 	if (sc->sc_type == COM_TYPE_PXA2x0)
456 		sc->sc_ier = IER_EUART;
457 	else
458 		sc->sc_ier = 0;
459 
460 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
461 
462 	if ((bus_space_is_equal(regsp->cr_iot, comcons_info.regs.cr_iot) &&
463 	    regsp->cr_iobase == comcons_info.regs.cr_iobase) || force_console) {
464 		comconsattached = 1;
465 
466 		if (force_console)
467 			memcpy(regsp, &comcons_info.regs, sizeof(*regsp));
468 
469 		if (cn_tab == NULL && comcnreattach() != 0) {
470 			printf("can't re-init serial console @%lx\n",
471 			    (u_long)comcons_info.regs.cr_iobase);
472 		}
473 
474 		switch (sc->sc_type) {
475 		case COM_TYPE_16750:
476 		case COM_TYPE_DW_APB:
477 			/* Use in comintr(). */
478  			sc->sc_lcr = cflag2lcr(comcons_info.cflag);
479 			break;
480 		}
481 
482 		/* Make sure the console is always "hardwired". */
483 		delay(10000);			/* wait for output to finish */
484 		if (is_console) {
485 			SET(sc->sc_hwflags, COM_HW_CONSOLE);
486 		}
487 
488 		SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
489 	}
490 
491 	/* Probe for FIFO */
492 	switch (sc->sc_type) {
493 	case COM_TYPE_HAYESP:
494 		goto fifodone;
495 
496 	case COM_TYPE_AU1x00:
497 		sc->sc_fifolen = 16;
498 		fifo_msg = "Au1X00 UART, working fifo";
499 		SET(sc->sc_hwflags, COM_HW_FIFO);
500 		goto fifodelay;
501 
502 	case COM_TYPE_16550_NOERS:
503 		sc->sc_fifolen = 16;
504 		fifo_msg = "ns16650, no ERS, working fifo";
505 		SET(sc->sc_hwflags, COM_HW_FIFO);
506 		goto fifodelay;
507 
508 	case COM_TYPE_OMAP:
509 		sc->sc_fifolen = 64;
510 		fifo_msg = "OMAP UART, working fifo";
511 		SET(sc->sc_hwflags, COM_HW_FIFO);
512 		goto fifodelay;
513 
514 	case COM_TYPE_INGENIC:
515 		sc->sc_fifolen = 16;
516 		fifo_msg = "Ingenic UART, working fifo";
517 		SET(sc->sc_hwflags, COM_HW_FIFO);
518 		SET(sc->sc_hwflags, COM_HW_NOIEN);
519 		goto fifodelay;
520 
521 	case COM_TYPE_TEGRA:
522 		sc->sc_fifolen = 8;
523 		fifo_msg = "Tegra UART, working fifo";
524 		SET(sc->sc_hwflags, COM_HW_FIFO);
525 		CSR_WRITE_1(regsp, COM_REG_FIFO,
526 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
527 		goto fifodelay;
528 
529 	case COM_TYPE_BCMAUXUART:
530 		sc->sc_fifolen = 1;
531 		fifo_msg = "BCM AUX UART, working fifo";
532 		SET(sc->sc_hwflags, COM_HW_FIFO);
533 		CSR_WRITE_1(regsp, COM_REG_FIFO,
534 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
535 		goto fifodelay;
536 	}
537 
538 	sc->sc_fifolen = 1;
539 	/* look for a NS 16550AF UART with FIFOs */
540 	if (sc->sc_type == COM_TYPE_INGENIC) {
541 		CSR_WRITE_1(regsp, COM_REG_FIFO,
542 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
543 		    FIFO_TRIGGER_14 | FIFO_UART_ON);
544 	} else
545 		CSR_WRITE_1(regsp, COM_REG_FIFO,
546 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_14);
547 	delay(100);
548 	if (ISSET(CSR_READ_1(regsp, COM_REG_IIR), IIR_FIFO_MASK)
549 	    == IIR_FIFO_MASK)
550 		if (ISSET(CSR_READ_1(regsp, COM_REG_FIFO), FIFO_TRIGGER_14)
551 		    == FIFO_TRIGGER_14) {
552 			SET(sc->sc_hwflags, COM_HW_FIFO);
553 
554 			fifo_msg = "ns16550a, working fifo";
555 
556 			/*
557 			 * IIR changes into the EFR if LCR is set to LCR_EERS
558 			 * on 16650s. We also know IIR != 0 at this point.
559 			 * Write 0 into the EFR, and read it. If the result
560 			 * is 0, we have a 16650.
561 			 *
562 			 * Older 16650s were broken; the test to detect them
563 			 * is taken from the Linux driver. Apparently
564 			 * setting DLAB enable gives access to the EFR on
565 			 * these chips.
566 			 */
567 			if (sc->sc_type == COM_TYPE_16650) {
568 				lcr = CSR_READ_1(regsp, COM_REG_LCR);
569 				CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
570 				CSR_WRITE_1(regsp, COM_REG_EFR, 0);
571 				if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
572 					CSR_WRITE_1(regsp, COM_REG_LCR,
573 					    lcr | LCR_DLAB);
574 					if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
575 						CLR(sc->sc_hwflags, COM_HW_FIFO);
576 						sc->sc_fifolen = 0;
577 					} else {
578 						SET(sc->sc_hwflags, COM_HW_FLOW);
579 						sc->sc_fifolen = 32;
580 					}
581 				} else
582 					sc->sc_fifolen = 16;
583 
584 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
585 				if (sc->sc_fifolen == 0)
586 					fifo_msg = "st16650, broken fifo";
587 				else if (sc->sc_fifolen == 32)
588 					fifo_msg = "st16650a, working fifo";
589 				else
590 					fifo_msg = "ns16550a, working fifo";
591 			}
592 
593 			/*
594 			 * TL16C750 can enable 64byte FIFO, only when DLAB
595 			 * is 1.  However, some 16750 may always enable.  For
596 			 * example, restrictions according to DLAB in a data
597 			 * sheet for SC16C750 were not described.
598 			 * Please enable 'options COM_16650', supposing you
599 			 * use SC16C750.  Probably 32 bytes of FIFO and HW FLOW
600 			 * should become effective.
601 			 */
602 			if (sc->sc_type == COM_TYPE_16750) {
603 				uint8_t iir1, iir2;
604 				uint8_t fcr = FIFO_ENABLE | FIFO_TRIGGER_14;
605 
606 				lcr = CSR_READ_1(regsp, COM_REG_LCR);
607 				CSR_WRITE_1(regsp, COM_REG_LCR,
608 				    lcr & ~LCR_DLAB);
609 				CSR_WRITE_1(regsp, COM_REG_FIFO,
610 				    fcr | FIFO_64B_ENABLE);
611 				iir1 = CSR_READ_1(regsp, COM_REG_IIR);
612 				CSR_WRITE_1(regsp, COM_REG_FIFO, fcr);
613 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr | LCR_DLAB);
614 				CSR_WRITE_1(regsp, COM_REG_FIFO,
615 				    fcr | FIFO_64B_ENABLE);
616 				iir2 = CSR_READ_1(regsp, COM_REG_IIR);
617 
618 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
619 
620 				if (!ISSET(iir1, IIR_64B_FIFO) &&
621 				    ISSET(iir2, IIR_64B_FIFO)) {
622 					/* It is TL16C750. */
623 					sc->sc_fifolen = 64;
624 					SET(sc->sc_hwflags, COM_HW_AFE);
625 				} else
626 					CSR_WRITE_1(regsp, COM_REG_FIFO, fcr);
627 
628 				if (sc->sc_fifolen == 64)
629 					fifo_msg = "tl16c750, working fifo";
630 				else
631 					fifo_msg = "ns16750, working fifo";
632 			}
633 		} else
634 			fifo_msg = "ns16550, broken fifo";
635 	else
636 		fifo_msg = "ns8250 or ns16450, no fifo";
637 	CSR_WRITE_1(regsp, COM_REG_FIFO, 0);
638 
639 fifodelay:
640 	/*
641 	 * Some chips will clear down both Tx and Rx FIFOs when zero is
642 	 * written to com_fifo. If this chip is the console, writing zero
643 	 * results in some of the chip/FIFO description being lost, so delay
644 	 * printing it until now.
645 	 */
646 	delay(10);
647 	aprint_normal(": %s\n", fifo_msg);
648 	if (ISSET(sc->sc_hwflags, COM_HW_TXFIFO_DISABLE)) {
649 		sc->sc_fifolen = 1;
650 		aprint_normal_dev(sc->sc_dev, "txfifo disabled\n");
651 	}
652 
653 fifodone:
654 
655 	tp = tty_alloc();
656 	tp->t_oproc = comstart;
657 	tp->t_param = comparam;
658 	tp->t_hwiflow = comhwiflow;
659 	tp->t_softc = sc;
660 
661 	sc->sc_tty = tp;
662 	sc->sc_rbuf = malloc(com_rbuf_size << 1, M_DEVBUF, M_NOWAIT);
663 	sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
664 	sc->sc_rbavail = com_rbuf_size;
665 	if (sc->sc_rbuf == NULL) {
666 		aprint_error_dev(sc->sc_dev,
667 		    "unable to allocate ring buffer\n");
668 		return;
669 	}
670 	sc->sc_ebuf = sc->sc_rbuf + (com_rbuf_size << 1);
671 
672 	tty_attach(tp);
673 
674 	if (!ISSET(sc->sc_hwflags, COM_HW_NOIEN))
675 		SET(sc->sc_mcr, MCR_IENABLE);
676 
677 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
678 		int maj;
679 
680 		/* locate the major number */
681 		maj = cdevsw_lookup_major(&com_cdevsw);
682 
683 		tp->t_dev = cn_tab->cn_dev = makedev(maj,
684 						     device_unit(sc->sc_dev));
685 
686 		aprint_normal_dev(sc->sc_dev, "console\n");
687 	}
688 
689 #ifdef KGDB
690 	/*
691 	 * Allow kgdb to "take over" this port.  If this is
692 	 * not the console and is the kgdb device, it has
693 	 * exclusive use.  If it's the console _and_ the
694 	 * kgdb device, it doesn't.
695 	 */
696 	if (bus_space_is_equal(regsp->cr_iot, comkgdbregs.cr_iot) &&
697 	    regsp->cr_iobase == comkgdbregs.cr_iobase) {
698 		if (!ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
699 			com_kgdb_attached = 1;
700 
701 			SET(sc->sc_hwflags, COM_HW_KGDB);
702 		}
703 		aprint_normal_dev(sc->sc_dev, "kgdb\n");
704 	}
705 #endif
706 
707 	sc->sc_si = softint_establish(SOFTINT_SERIAL, comsoft, sc);
708 
709 #ifdef RND_COM
710 	rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
711 			  RND_TYPE_TTY, RND_FLAG_DEFAULT);
712 #endif
713 
714 	/* if there are no enable/disable functions, assume the device
715 	   is always enabled */
716 	if (!sc->enable)
717 		sc->enabled = 1;
718 
719 	com_config(sc);
720 
721 	SET(sc->sc_hwflags, COM_HW_DEV_OK);
722 
723 	if (ISSET(sc->sc_hwflags, COM_HW_POLL))
724 		callout_schedule(&sc->sc_poll_callout, 1);
725 }
726 
727 void
728 com_config(struct com_softc *sc)
729 {
730 	struct com_regs *regsp = &sc->sc_regs;
731 
732 	/* Disable interrupts before configuring the device. */
733 	if (sc->sc_type == COM_TYPE_PXA2x0)
734 		sc->sc_ier = IER_EUART;
735 	else
736 		sc->sc_ier = 0;
737 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
738 	(void) CSR_READ_1(regsp, COM_REG_IIR);
739 
740 	/* Look for a Hayes ESP board. */
741 	if (sc->sc_type == COM_TYPE_HAYESP) {
742 
743 		/* Set 16550 compatibility mode */
744 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
745 				  HAYESP_SETMODE);
746 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
747 				  HAYESP_MODE_FIFO|HAYESP_MODE_RTS|
748 				  HAYESP_MODE_SCALE);
749 
750 		/* Set RTS/CTS flow control */
751 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
752 				  HAYESP_SETFLOWTYPE);
753 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
754 				  HAYESP_FLOW_RTS);
755 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
756 				  HAYESP_FLOW_CTS);
757 
758 		/* Set flow control levels */
759 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
760 				  HAYESP_SETRXFLOW);
761 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
762 				  HAYESP_HIBYTE(HAYESP_RXHIWMARK));
763 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
764 				  HAYESP_LOBYTE(HAYESP_RXHIWMARK));
765 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
766 				  HAYESP_HIBYTE(HAYESP_RXLOWMARK));
767 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
768 				  HAYESP_LOBYTE(HAYESP_RXLOWMARK));
769 	}
770 
771 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE|COM_HW_KGDB))
772 		com_enable_debugport(sc);
773 }
774 
775 #if 0
776 static int
777 comcngetc_detached(dev_t dev)
778 {
779 	return 0;
780 }
781 
782 static void
783 comcnputc_detached(dev_t dev, int c)
784 {
785 }
786 #endif
787 
788 int
789 com_detach(device_t self, int flags)
790 {
791 	struct com_softc *sc = device_private(self);
792 	int maj, mn;
793 
794 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
795 		return EBUSY;
796 
797 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE) &&
798 	    (flags & DETACH_SHUTDOWN) != 0)
799 		return EBUSY;
800 
801 	if (sc->disable != NULL && sc->enabled != 0) {
802 		(*sc->disable)(sc);
803 		sc->enabled = 0;
804 	}
805 
806 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
807 		comconsattached = 0;
808 		cn_tab = NULL;
809 	}
810 
811 	/* locate the major number */
812 	maj = cdevsw_lookup_major(&com_cdevsw);
813 
814 	/* Nuke the vnodes for any open instances. */
815 	mn = device_unit(self);
816 	vdevgone(maj, mn, mn, VCHR);
817 
818 	mn |= COMDIALOUT_MASK;
819 	vdevgone(maj, mn, mn, VCHR);
820 
821 	if (sc->sc_rbuf == NULL) {
822 		/*
823 		 * Ring buffer allocation failed in the com_attach_subr,
824 		 * only the tty is allocated, and nothing else.
825 		 */
826 		tty_free(sc->sc_tty);
827 		return 0;
828 	}
829 
830 	/* Free the receive buffer. */
831 	free(sc->sc_rbuf, M_DEVBUF);
832 
833 	/* Detach and free the tty. */
834 	tty_detach(sc->sc_tty);
835 	tty_free(sc->sc_tty);
836 
837 	/* Unhook the soft interrupt handler. */
838 	softint_disestablish(sc->sc_si);
839 
840 #ifdef RND_COM
841 	/* Unhook the entropy source. */
842 	rnd_detach_source(&sc->rnd_source);
843 #endif
844 	callout_destroy(&sc->sc_diag_callout);
845 
846 	/* Destroy the lock. */
847 	mutex_destroy(&sc->sc_lock);
848 
849 	return (0);
850 }
851 
852 void
853 com_shutdown(struct com_softc *sc)
854 {
855 	struct tty *tp = sc->sc_tty;
856 
857 	mutex_spin_enter(&sc->sc_lock);
858 
859 	/* If we were asserting flow control, then deassert it. */
860 	SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
861 	com_hwiflow(sc);
862 
863 	/* Clear any break condition set with TIOCSBRK. */
864 	com_break(sc, 0);
865 
866 	/*
867 	 * Hang up if necessary.  Wait a bit, so the other side has time to
868 	 * notice even if we immediately open the port again.
869 	 * Avoid tsleeping above splhigh().
870 	 */
871 	if (ISSET(tp->t_cflag, HUPCL)) {
872 		com_modem(sc, 0);
873 		mutex_spin_exit(&sc->sc_lock);
874 		/* XXX will only timeout */
875 		(void) kpause(ttclos, false, hz, NULL);
876 		mutex_spin_enter(&sc->sc_lock);
877 	}
878 
879 	/* Turn off interrupts. */
880 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
881 		sc->sc_ier = IER_ERLS; /* interrupt on line break */
882 		if ((sc->sc_type == COM_TYPE_PXA2x0) ||
883 		    (sc->sc_type == COM_TYPE_INGENIC) ||
884 		    (sc->sc_type == COM_TYPE_TEGRA))
885 			sc->sc_ier |= IER_ERXTOUT;
886 	} else
887 		sc->sc_ier = 0;
888 
889 	if (sc->sc_type == COM_TYPE_PXA2x0)
890 		sc->sc_ier |= IER_EUART;
891 
892 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
893 
894 	mutex_spin_exit(&sc->sc_lock);
895 
896 	if (sc->disable) {
897 #ifdef DIAGNOSTIC
898 		if (!sc->enabled)
899 			panic("com_shutdown: not enabled?");
900 #endif
901 		(*sc->disable)(sc);
902 		sc->enabled = 0;
903 	}
904 }
905 
906 int
907 comopen(dev_t dev, int flag, int mode, struct lwp *l)
908 {
909 	struct com_softc *sc;
910 	struct tty *tp;
911 	int s;
912 	int error;
913 
914 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
915 	if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK) ||
916 		sc->sc_rbuf == NULL)
917 		return (ENXIO);
918 
919 	if (!device_is_active(sc->sc_dev))
920 		return (ENXIO);
921 
922 #ifdef KGDB
923 	/*
924 	 * If this is the kgdb port, no other use is permitted.
925 	 */
926 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
927 		return (EBUSY);
928 #endif
929 
930 	tp = sc->sc_tty;
931 
932 	/*
933 	 * If the device is exclusively for kernel use, deny userland
934 	 * open.
935 	 */
936 	if (ISSET(tp->t_state, TS_KERN_ONLY))
937 		return (EBUSY);
938 
939 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
940 		return (EBUSY);
941 
942 	s = spltty();
943 
944 	/*
945 	 * Do the following iff this is a first open.
946 	 */
947 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
948 		struct termios t;
949 
950 		tp->t_dev = dev;
951 
952 		if (sc->enable) {
953 			if ((*sc->enable)(sc)) {
954 				splx(s);
955 				aprint_error_dev(sc->sc_dev,
956 				    "device enable failed\n");
957 				return (EIO);
958 			}
959 			mutex_spin_enter(&sc->sc_lock);
960 			sc->enabled = 1;
961 			com_config(sc);
962 		} else {
963 			mutex_spin_enter(&sc->sc_lock);
964 		}
965 
966 		/* Turn on interrupts. */
967 		sc->sc_ier = IER_ERXRDY | IER_ERLS;
968 		if (!ISSET(tp->t_cflag, CLOCAL))
969 			sc->sc_ier |= IER_EMSC;
970 
971 		if (sc->sc_type == COM_TYPE_PXA2x0)
972 			sc->sc_ier |= IER_EUART | IER_ERXTOUT;
973 		else if (sc->sc_type == COM_TYPE_INGENIC ||
974 			 sc->sc_type == COM_TYPE_TEGRA)
975 			sc->sc_ier |= IER_ERXTOUT;
976 		CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
977 
978 		/* Fetch the current modem control status, needed later. */
979 		sc->sc_msr = CSR_READ_1(&sc->sc_regs, COM_REG_MSR);
980 
981 		/* Clear PPS capture state on first open. */
982 		mutex_spin_enter(&timecounter_lock);
983 		memset(&sc->sc_pps_state, 0, sizeof(sc->sc_pps_state));
984 		sc->sc_pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
985 		pps_init(&sc->sc_pps_state);
986 		mutex_spin_exit(&timecounter_lock);
987 
988 		mutex_spin_exit(&sc->sc_lock);
989 
990 		/*
991 		 * Initialize the termios status to the defaults.  Add in the
992 		 * sticky bits from TIOCSFLAGS.
993 		 */
994 		if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
995 			t.c_ospeed = comcons_info.rate;
996 			t.c_cflag = comcons_info.cflag;
997 		} else {
998 			t.c_ospeed = TTYDEF_SPEED;
999 			t.c_cflag = TTYDEF_CFLAG;
1000 		}
1001 		t.c_ispeed = t.c_ospeed;
1002 		if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
1003 			SET(t.c_cflag, CLOCAL);
1004 		if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
1005 			SET(t.c_cflag, CRTSCTS);
1006 		if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
1007 			SET(t.c_cflag, MDMBUF);
1008 		/* Make sure comparam() will do something. */
1009 		tp->t_ospeed = 0;
1010 		(void) comparam(tp, &t);
1011 		tp->t_iflag = TTYDEF_IFLAG;
1012 		tp->t_oflag = TTYDEF_OFLAG;
1013 		tp->t_lflag = TTYDEF_LFLAG;
1014 		ttychars(tp);
1015 		ttsetwater(tp);
1016 
1017 		mutex_spin_enter(&sc->sc_lock);
1018 
1019 		/*
1020 		 * Turn on DTR.  We must always do this, even if carrier is not
1021 		 * present, because otherwise we'd have to use TIOCSDTR
1022 		 * immediately after setting CLOCAL, which applications do not
1023 		 * expect.  We always assert DTR while the device is open
1024 		 * unless explicitly requested to deassert it.
1025 		 */
1026 		com_modem(sc, 1);
1027 
1028 		/* Clear the input ring, and unblock. */
1029 		sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
1030 		sc->sc_rbavail = com_rbuf_size;
1031 		com_iflush(sc);
1032 		CLR(sc->sc_rx_flags, RX_ANY_BLOCK);
1033 		com_hwiflow(sc);
1034 
1035 #ifdef COM_DEBUG
1036 		if (com_debug)
1037 			comstatus(sc, "comopen  ");
1038 #endif
1039 
1040 		mutex_spin_exit(&sc->sc_lock);
1041 	}
1042 
1043 	splx(s);
1044 
1045 	error = ttyopen(tp, COMDIALOUT(dev), ISSET(flag, O_NONBLOCK));
1046 	if (error)
1047 		goto bad;
1048 
1049 	error = (*tp->t_linesw->l_open)(dev, tp);
1050 	if (error)
1051 		goto bad;
1052 
1053 	return (0);
1054 
1055 bad:
1056 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
1057 		/*
1058 		 * We failed to open the device, and nobody else had it opened.
1059 		 * Clean up the state as appropriate.
1060 		 */
1061 		com_shutdown(sc);
1062 	}
1063 
1064 	return (error);
1065 }
1066 
1067 int
1068 comclose(dev_t dev, int flag, int mode, struct lwp *l)
1069 {
1070 	struct com_softc *sc =
1071 	    device_lookup_private(&com_cd, COMUNIT(dev));
1072 	struct tty *tp = sc->sc_tty;
1073 
1074 	/* XXX This is for cons.c. */
1075 	if (!ISSET(tp->t_state, TS_ISOPEN))
1076 		return (0);
1077 	/*
1078 	 * If the device is exclusively for kernel use, deny userland
1079 	 * close.
1080 	 */
1081 	if (ISSET(tp->t_state, TS_KERN_ONLY))
1082 		return (0);
1083 
1084 	(*tp->t_linesw->l_close)(tp, flag);
1085 	ttyclose(tp);
1086 
1087 	if (COM_ISALIVE(sc) == 0)
1088 		return (0);
1089 
1090 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
1091 		/*
1092 		 * Although we got a last close, the device may still be in
1093 		 * use; e.g. if this was the dialout node, and there are still
1094 		 * processes waiting for carrier on the non-dialout node.
1095 		 */
1096 		com_shutdown(sc);
1097 	}
1098 
1099 	return (0);
1100 }
1101 
1102 int
1103 comread(dev_t dev, struct uio *uio, int flag)
1104 {
1105 	struct com_softc *sc =
1106 	    device_lookup_private(&com_cd, COMUNIT(dev));
1107 	struct tty *tp = sc->sc_tty;
1108 
1109 	if (COM_ISALIVE(sc) == 0)
1110 		return (EIO);
1111 
1112 	return ((*tp->t_linesw->l_read)(tp, uio, flag));
1113 }
1114 
1115 int
1116 comwrite(dev_t dev, struct uio *uio, int flag)
1117 {
1118 	struct com_softc *sc =
1119 	    device_lookup_private(&com_cd, COMUNIT(dev));
1120 	struct tty *tp = sc->sc_tty;
1121 
1122 	if (COM_ISALIVE(sc) == 0)
1123 		return (EIO);
1124 
1125 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
1126 }
1127 
1128 int
1129 compoll(dev_t dev, int events, struct lwp *l)
1130 {
1131 	struct com_softc *sc =
1132 	    device_lookup_private(&com_cd, COMUNIT(dev));
1133 	struct tty *tp = sc->sc_tty;
1134 
1135 	if (COM_ISALIVE(sc) == 0)
1136 		return (POLLHUP);
1137 
1138 	return ((*tp->t_linesw->l_poll)(tp, events, l));
1139 }
1140 
1141 struct tty *
1142 comtty(dev_t dev)
1143 {
1144 	struct com_softc *sc =
1145 	    device_lookup_private(&com_cd, COMUNIT(dev));
1146 	struct tty *tp = sc->sc_tty;
1147 
1148 	return (tp);
1149 }
1150 
1151 int
1152 comioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
1153 {
1154 	struct com_softc *sc;
1155 	struct tty *tp;
1156 	int error;
1157 
1158 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
1159 	if (sc == NULL)
1160 		return ENXIO;
1161 	if (COM_ISALIVE(sc) == 0)
1162 		return (EIO);
1163 
1164 	tp = sc->sc_tty;
1165 
1166 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
1167 	if (error != EPASSTHROUGH)
1168 		return (error);
1169 
1170 	error = ttioctl(tp, cmd, data, flag, l);
1171 	if (error != EPASSTHROUGH)
1172 		return (error);
1173 
1174 	error = 0;
1175 	switch (cmd) {
1176 	case TIOCSFLAGS:
1177 		error = kauth_authorize_device_tty(l->l_cred,
1178 		    KAUTH_DEVICE_TTY_PRIVSET, tp);
1179 		break;
1180 	default:
1181 		/* nothing */
1182 		break;
1183 	}
1184 	if (error) {
1185 		return error;
1186 	}
1187 
1188 	mutex_spin_enter(&sc->sc_lock);
1189 
1190 	switch (cmd) {
1191 	case TIOCSBRK:
1192 		com_break(sc, 1);
1193 		break;
1194 
1195 	case TIOCCBRK:
1196 		com_break(sc, 0);
1197 		break;
1198 
1199 	case TIOCSDTR:
1200 		com_modem(sc, 1);
1201 		break;
1202 
1203 	case TIOCCDTR:
1204 		com_modem(sc, 0);
1205 		break;
1206 
1207 	case TIOCGFLAGS:
1208 		*(int *)data = sc->sc_swflags;
1209 		break;
1210 
1211 	case TIOCSFLAGS:
1212 		sc->sc_swflags = *(int *)data;
1213 		break;
1214 
1215 	case TIOCMSET:
1216 	case TIOCMBIS:
1217 	case TIOCMBIC:
1218 		tiocm_to_com(sc, cmd, *(int *)data);
1219 		break;
1220 
1221 	case TIOCMGET:
1222 		*(int *)data = com_to_tiocm(sc);
1223 		break;
1224 
1225 	case PPS_IOC_CREATE:
1226 	case PPS_IOC_DESTROY:
1227 	case PPS_IOC_GETPARAMS:
1228 	case PPS_IOC_SETPARAMS:
1229 	case PPS_IOC_GETCAP:
1230 	case PPS_IOC_FETCH:
1231 #ifdef PPS_SYNC
1232 	case PPS_IOC_KCBIND:
1233 #endif
1234 		mutex_spin_enter(&timecounter_lock);
1235 		error = pps_ioctl(cmd, data, &sc->sc_pps_state);
1236 		mutex_spin_exit(&timecounter_lock);
1237 		break;
1238 
1239 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
1240 		mutex_spin_enter(&timecounter_lock);
1241 #ifndef PPS_TRAILING_EDGE
1242 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1243 		    &sc->sc_pps_state.ppsinfo.assert_timestamp);
1244 #else
1245 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
1246 		    &sc->sc_pps_state.ppsinfo.clear_timestamp);
1247 #endif
1248 		mutex_spin_exit(&timecounter_lock);
1249 		break;
1250 
1251 	default:
1252 		error = EPASSTHROUGH;
1253 		break;
1254 	}
1255 
1256 	mutex_spin_exit(&sc->sc_lock);
1257 
1258 #ifdef COM_DEBUG
1259 	if (com_debug)
1260 		comstatus(sc, "comioctl ");
1261 #endif
1262 
1263 	return (error);
1264 }
1265 
1266 integrate void
1267 com_schedrx(struct com_softc *sc)
1268 {
1269 
1270 	sc->sc_rx_ready = 1;
1271 
1272 	/* Wake up the poller. */
1273 	softint_schedule(sc->sc_si);
1274 }
1275 
1276 void
1277 com_break(struct com_softc *sc, int onoff)
1278 {
1279 
1280 	if (onoff)
1281 		SET(sc->sc_lcr, LCR_SBREAK);
1282 	else
1283 		CLR(sc->sc_lcr, LCR_SBREAK);
1284 
1285 	if (!sc->sc_heldchange) {
1286 		if (sc->sc_tx_busy) {
1287 			sc->sc_heldtbc = sc->sc_tbc;
1288 			sc->sc_tbc = 0;
1289 			sc->sc_heldchange = 1;
1290 		} else
1291 			com_loadchannelregs(sc);
1292 	}
1293 }
1294 
1295 void
1296 com_modem(struct com_softc *sc, int onoff)
1297 {
1298 
1299 	if (sc->sc_mcr_dtr == 0)
1300 		return;
1301 
1302 	if (onoff)
1303 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1304 	else
1305 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1306 
1307 	if (!sc->sc_heldchange) {
1308 		if (sc->sc_tx_busy) {
1309 			sc->sc_heldtbc = sc->sc_tbc;
1310 			sc->sc_tbc = 0;
1311 			sc->sc_heldchange = 1;
1312 		} else
1313 			com_loadchannelregs(sc);
1314 	}
1315 }
1316 
1317 void
1318 tiocm_to_com(struct com_softc *sc, u_long how, int ttybits)
1319 {
1320 	u_char combits;
1321 
1322 	combits = 0;
1323 	if (ISSET(ttybits, TIOCM_DTR))
1324 		SET(combits, MCR_DTR);
1325 	if (ISSET(ttybits, TIOCM_RTS))
1326 		SET(combits, MCR_RTS);
1327 
1328 	switch (how) {
1329 	case TIOCMBIC:
1330 		CLR(sc->sc_mcr, combits);
1331 		break;
1332 
1333 	case TIOCMBIS:
1334 		SET(sc->sc_mcr, combits);
1335 		break;
1336 
1337 	case TIOCMSET:
1338 		CLR(sc->sc_mcr, MCR_DTR | MCR_RTS);
1339 		SET(sc->sc_mcr, combits);
1340 		break;
1341 	}
1342 
1343 	if (!sc->sc_heldchange) {
1344 		if (sc->sc_tx_busy) {
1345 			sc->sc_heldtbc = sc->sc_tbc;
1346 			sc->sc_tbc = 0;
1347 			sc->sc_heldchange = 1;
1348 		} else
1349 			com_loadchannelregs(sc);
1350 	}
1351 }
1352 
1353 int
1354 com_to_tiocm(struct com_softc *sc)
1355 {
1356 	u_char combits;
1357 	int ttybits = 0;
1358 
1359 	combits = sc->sc_mcr;
1360 	if (ISSET(combits, MCR_DTR))
1361 		SET(ttybits, TIOCM_DTR);
1362 	if (ISSET(combits, MCR_RTS))
1363 		SET(ttybits, TIOCM_RTS);
1364 
1365 	combits = sc->sc_msr;
1366 	if (sc->sc_type == COM_TYPE_INGENIC) {
1367 		SET(ttybits, TIOCM_CD);
1368 	} else {
1369 		if (ISSET(combits, MSR_DCD))
1370 			SET(ttybits, TIOCM_CD);
1371 	}
1372 	if (ISSET(combits, MSR_CTS))
1373 		SET(ttybits, TIOCM_CTS);
1374 	if (ISSET(combits, MSR_DSR))
1375 		SET(ttybits, TIOCM_DSR);
1376 	if (ISSET(combits, MSR_RI | MSR_TERI))
1377 		SET(ttybits, TIOCM_RI);
1378 
1379 	if (ISSET(sc->sc_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS | IER_EMSC))
1380 		SET(ttybits, TIOCM_LE);
1381 
1382 	return (ttybits);
1383 }
1384 
1385 static u_char
1386 cflag2lcr(tcflag_t cflag)
1387 {
1388 	u_char lcr = 0;
1389 
1390 	switch (ISSET(cflag, CSIZE)) {
1391 	case CS5:
1392 		SET(lcr, LCR_5BITS);
1393 		break;
1394 	case CS6:
1395 		SET(lcr, LCR_6BITS);
1396 		break;
1397 	case CS7:
1398 		SET(lcr, LCR_7BITS);
1399 		break;
1400 	case CS8:
1401 		SET(lcr, LCR_8BITS);
1402 		break;
1403 	}
1404 	if (ISSET(cflag, PARENB)) {
1405 		SET(lcr, LCR_PENAB);
1406 		if (!ISSET(cflag, PARODD))
1407 			SET(lcr, LCR_PEVEN);
1408 	}
1409 	if (ISSET(cflag, CSTOPB))
1410 		SET(lcr, LCR_STOPB);
1411 
1412 	return (lcr);
1413 }
1414 
1415 int
1416 comparam(struct tty *tp, struct termios *t)
1417 {
1418 	struct com_softc *sc =
1419 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1420 	int ospeed;
1421 	u_char lcr;
1422 
1423 	if (COM_ISALIVE(sc) == 0)
1424 		return (EIO);
1425 
1426 	if (sc->sc_type == COM_TYPE_HAYESP) {
1427 		int prescaler, speed;
1428 
1429 		/*
1430 		 * Calculate UART clock prescaler.  It should be in
1431 		 * range of 0 .. 3.
1432 		 */
1433 		for (prescaler = 0, speed = t->c_ospeed; prescaler < 4;
1434 		    prescaler++, speed /= 2)
1435 			if ((ospeed = comspeed(speed, sc->sc_frequency,
1436 					       sc->sc_type)) > 0)
1437 				break;
1438 
1439 		if (prescaler == 4)
1440 			return (EINVAL);
1441 		sc->sc_prescaler = prescaler;
1442 	} else
1443 		ospeed = comspeed(t->c_ospeed, sc->sc_frequency, sc->sc_type);
1444 
1445 	/* Check requested parameters. */
1446 	if (ospeed < 0)
1447 		return (EINVAL);
1448 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
1449 		return (EINVAL);
1450 
1451 	/*
1452 	 * For the console, always force CLOCAL and !HUPCL, so that the port
1453 	 * is always active.
1454 	 */
1455 	if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
1456 	    ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
1457 		SET(t->c_cflag, CLOCAL);
1458 		CLR(t->c_cflag, HUPCL);
1459 	}
1460 
1461 	/*
1462 	 * If there were no changes, don't do anything.  This avoids dropping
1463 	 * input and improves performance when all we did was frob things like
1464 	 * VMIN and VTIME.
1465 	 */
1466 	if (tp->t_ospeed == t->c_ospeed &&
1467 	    tp->t_cflag == t->c_cflag)
1468 		return (0);
1469 
1470 	lcr = ISSET(sc->sc_lcr, LCR_SBREAK) | cflag2lcr(t->c_cflag);
1471 
1472 	mutex_spin_enter(&sc->sc_lock);
1473 
1474 	sc->sc_lcr = lcr;
1475 
1476 	/*
1477 	 * If we're not in a mode that assumes a connection is present, then
1478 	 * ignore carrier changes.
1479 	 */
1480 	if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
1481 		sc->sc_msr_dcd = 0;
1482 	else
1483 		sc->sc_msr_dcd = MSR_DCD;
1484 	/*
1485 	 * Set the flow control pins depending on the current flow control
1486 	 * mode.
1487 	 */
1488 	if (ISSET(t->c_cflag, CRTSCTS)) {
1489 		sc->sc_mcr_dtr = MCR_DTR;
1490 		sc->sc_mcr_rts = MCR_RTS;
1491 		sc->sc_msr_cts = MSR_CTS;
1492 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1493 			SET(sc->sc_mcr, MCR_AFE);
1494 		} else {
1495 			sc->sc_efr = EFR_AUTORTS | EFR_AUTOCTS;
1496 		}
1497 	} else if (ISSET(t->c_cflag, MDMBUF)) {
1498 		/*
1499 		 * For DTR/DCD flow control, make sure we don't toggle DTR for
1500 		 * carrier detection.
1501 		 */
1502 		sc->sc_mcr_dtr = 0;
1503 		sc->sc_mcr_rts = MCR_DTR;
1504 		sc->sc_msr_cts = MSR_DCD;
1505 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1506 			CLR(sc->sc_mcr, MCR_AFE);
1507 		} else {
1508 			sc->sc_efr = 0;
1509 		}
1510 	} else {
1511 		/*
1512 		 * If no flow control, then always set RTS.  This will make
1513 		 * the other side happy if it mistakenly thinks we're doing
1514 		 * RTS/CTS flow control.
1515 		 */
1516 		sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
1517 		sc->sc_mcr_rts = 0;
1518 		sc->sc_msr_cts = 0;
1519 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
1520 			CLR(sc->sc_mcr, MCR_AFE);
1521 		} else {
1522 			sc->sc_efr = 0;
1523 		}
1524 		if (ISSET(sc->sc_mcr, MCR_DTR))
1525 			SET(sc->sc_mcr, MCR_RTS);
1526 		else
1527 			CLR(sc->sc_mcr, MCR_RTS);
1528 	}
1529 	sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;
1530 
1531 	if (t->c_ospeed == 0 && tp->t_ospeed != 0)
1532 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
1533 	else if (t->c_ospeed != 0 && tp->t_ospeed == 0)
1534 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
1535 
1536 	sc->sc_dlbl = ospeed;
1537 	sc->sc_dlbh = ospeed >> 8;
1538 
1539 	/*
1540 	 * Set the FIFO threshold based on the receive speed.
1541 	 *
1542 	 *  * If it's a low speed, it's probably a mouse or some other
1543 	 *    interactive device, so set the threshold low.
1544 	 *  * If it's a high speed, trim the trigger level down to prevent
1545 	 *    overflows.
1546 	 *  * Otherwise set it a bit higher.
1547 	 */
1548 	if (sc->sc_type == COM_TYPE_HAYESP) {
1549 		sc->sc_fifo = FIFO_DMA_MODE | FIFO_ENABLE | FIFO_TRIGGER_8;
1550 	} else if (sc->sc_type == COM_TYPE_TEGRA) {
1551 		sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
1552 	} else if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
1553 		if (t->c_ospeed <= 1200)
1554 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
1555 		else if (t->c_ospeed <= 38400)
1556 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_8;
1557 		else
1558 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_4;
1559 	} else {
1560 		sc->sc_fifo = 0;
1561 	}
1562 
1563 	if (sc->sc_type == COM_TYPE_INGENIC)
1564 		sc->sc_fifo |= FIFO_UART_ON;
1565 
1566 	/* And copy to tty. */
1567 	tp->t_ispeed = t->c_ospeed;
1568 	tp->t_ospeed = t->c_ospeed;
1569 	tp->t_cflag = t->c_cflag;
1570 
1571 	if (!sc->sc_heldchange) {
1572 		if (sc->sc_tx_busy) {
1573 			sc->sc_heldtbc = sc->sc_tbc;
1574 			sc->sc_tbc = 0;
1575 			sc->sc_heldchange = 1;
1576 		} else
1577 			com_loadchannelregs(sc);
1578 	}
1579 
1580 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1581 		/* Disable the high water mark. */
1582 		sc->sc_r_hiwat = 0;
1583 		sc->sc_r_lowat = 0;
1584 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1585 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1586 			com_schedrx(sc);
1587 		}
1588 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
1589 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
1590 			com_hwiflow(sc);
1591 		}
1592 	} else {
1593 		sc->sc_r_hiwat = com_rbuf_hiwat;
1594 		sc->sc_r_lowat = com_rbuf_lowat;
1595 	}
1596 
1597 	mutex_spin_exit(&sc->sc_lock);
1598 
1599 	/*
1600 	 * Update the tty layer's idea of the carrier bit, in case we changed
1601 	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
1602 	 * explicit request.
1603 	 */
1604 	if (sc->sc_type == COM_TYPE_INGENIC) {
1605 		/* no DCD here */
1606 		(void) (*tp->t_linesw->l_modem)(tp, 1);
1607 	} else
1608 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, MSR_DCD));
1609 
1610 #ifdef COM_DEBUG
1611 	if (com_debug)
1612 		comstatus(sc, "comparam ");
1613 #endif
1614 
1615 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1616 		if (sc->sc_tx_stopped) {
1617 			sc->sc_tx_stopped = 0;
1618 			comstart(tp);
1619 		}
1620 	}
1621 
1622 	return (0);
1623 }
1624 
1625 void
1626 com_iflush(struct com_softc *sc)
1627 {
1628 	struct com_regs	*regsp = &sc->sc_regs;
1629 	uint8_t fifo;
1630 #ifdef DIAGNOSTIC
1631 	int reg;
1632 #endif
1633 	int timo;
1634 
1635 #ifdef DIAGNOSTIC
1636 	reg = 0xffff;
1637 #endif
1638 	timo = 50000;
1639 	/* flush any pending I/O */
1640 	while (ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)
1641 	    && --timo)
1642 #ifdef DIAGNOSTIC
1643 		reg =
1644 #else
1645 		    (void)
1646 #endif
1647 		    CSR_READ_1(regsp, COM_REG_RXDATA);
1648 #ifdef DIAGNOSTIC
1649 	if (!timo)
1650 		aprint_error_dev(sc->sc_dev, "com_iflush timeout %02x\n", reg);
1651 #endif
1652 
1653 	switch (sc->sc_type) {
1654 	case COM_TYPE_16750:
1655 	case COM_TYPE_DW_APB:
1656 		/*
1657 		 * Reset all Rx/Tx FIFO, preserve current FIFO length.
1658 		 * This should prevent triggering busy interrupt while
1659 		 * manipulating divisors.
1660 		 */
1661 		fifo = CSR_READ_1(regsp, COM_REG_FIFO) & (FIFO_TRIGGER_1 |
1662 		    FIFO_TRIGGER_4 | FIFO_TRIGGER_8 | FIFO_TRIGGER_14);
1663 		CSR_WRITE_1(regsp, COM_REG_FIFO,
1664 		    fifo | FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST);
1665 		delay(100);
1666 		break;
1667 	}
1668 }
1669 
1670 void
1671 com_loadchannelregs(struct com_softc *sc)
1672 {
1673 	struct com_regs *regsp = &sc->sc_regs;
1674 
1675 	/* XXXXX necessary? */
1676 	com_iflush(sc);
1677 
1678 	if (sc->sc_type == COM_TYPE_PXA2x0)
1679 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
1680 	else
1681 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
1682 
1683 	if (sc->sc_type == COM_TYPE_OMAP) {
1684 		/* disable before changing settings */
1685 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
1686 	}
1687 
1688 	if (ISSET(sc->sc_hwflags, COM_HW_FLOW)) {
1689 		KASSERT(sc->sc_type != COM_TYPE_AU1x00);
1690 		KASSERT(sc->sc_type != COM_TYPE_16550_NOERS);
1691 		/* no EFR on alchemy */
1692 		CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
1693 		CSR_WRITE_1(regsp, COM_REG_EFR, sc->sc_efr);
1694 	}
1695 	if (sc->sc_type == COM_TYPE_AU1x00) {
1696 		/* alchemy has single separate 16-bit clock divisor register */
1697 		CSR_WRITE_2(regsp, COM_REG_DLBL, sc->sc_dlbl +
1698 		    (sc->sc_dlbh << 8));
1699 	} else {
1700 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
1701 		CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
1702 		CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
1703 	}
1704 	CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
1705 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active = sc->sc_mcr);
1706 	CSR_WRITE_1(regsp, COM_REG_FIFO, sc->sc_fifo);
1707 	if (sc->sc_type == COM_TYPE_HAYESP) {
1708 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
1709 		    HAYESP_SETPRESCALER);
1710 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
1711 		    sc->sc_prescaler);
1712 	}
1713 	if (sc->sc_type == COM_TYPE_OMAP) {
1714 		/* setup the fifos.  the FCR value is not used as long
1715 		   as SCR[6] and SCR[7] are 0, which they are at reset
1716 		   and we never touch the SCR register */
1717 		uint8_t rx_fifo_trig = 40;
1718 		uint8_t tx_fifo_trig = 60;
1719 		uint8_t rx_start = 8;
1720 		uint8_t rx_halt = 60;
1721 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
1722 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
1723 
1724 		/* enable access to TCR & TLR */
1725 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr | MCR_TCR_TLR);
1726 
1727 		/* write tcr and tlr values */
1728 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
1729 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
1730 
1731 		/* disable access to TCR & TLR */
1732 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr);
1733 
1734 		/* enable again, but mode is based on speed */
1735 		if (sc->sc_tty->t_termios.c_ospeed > 230400) {
1736 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
1737 		} else {
1738 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
1739 		}
1740 	}
1741 
1742 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1743 }
1744 
1745 int
1746 comhwiflow(struct tty *tp, int block)
1747 {
1748 	struct com_softc *sc =
1749 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1750 
1751 	if (COM_ISALIVE(sc) == 0)
1752 		return (0);
1753 
1754 	if (sc->sc_mcr_rts == 0)
1755 		return (0);
1756 
1757 	mutex_spin_enter(&sc->sc_lock);
1758 
1759 	if (block) {
1760 		if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1761 			SET(sc->sc_rx_flags, RX_TTY_BLOCKED);
1762 			com_hwiflow(sc);
1763 		}
1764 	} else {
1765 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
1766 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1767 			com_schedrx(sc);
1768 		}
1769 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1770 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED);
1771 			com_hwiflow(sc);
1772 		}
1773 	}
1774 
1775 	mutex_spin_exit(&sc->sc_lock);
1776 	return (1);
1777 }
1778 
1779 /*
1780  * (un)block input via hw flowcontrol
1781  */
1782 void
1783 com_hwiflow(struct com_softc *sc)
1784 {
1785 	struct com_regs *regsp= &sc->sc_regs;
1786 
1787 	if (sc->sc_mcr_rts == 0)
1788 		return;
1789 
1790 	if (ISSET(sc->sc_rx_flags, RX_ANY_BLOCK)) {
1791 		CLR(sc->sc_mcr, sc->sc_mcr_rts);
1792 		CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
1793 	} else {
1794 		SET(sc->sc_mcr, sc->sc_mcr_rts);
1795 		SET(sc->sc_mcr_active, sc->sc_mcr_rts);
1796 	}
1797 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active);
1798 }
1799 
1800 
1801 void
1802 comstart(struct tty *tp)
1803 {
1804 	struct com_softc *sc =
1805 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1806 	struct com_regs *regsp = &sc->sc_regs;
1807 	int s;
1808 
1809 	if (COM_ISALIVE(sc) == 0)
1810 		return;
1811 
1812 	s = spltty();
1813 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
1814 		goto out;
1815 	if (sc->sc_tx_stopped)
1816 		goto out;
1817 	if (!ttypull(tp))
1818 		goto out;
1819 
1820 	/* Grab the first contiguous region of buffer space. */
1821 	{
1822 		u_char *tba;
1823 		int tbc;
1824 
1825 		tba = tp->t_outq.c_cf;
1826 		tbc = ndqb(&tp->t_outq, 0);
1827 
1828 		mutex_spin_enter(&sc->sc_lock);
1829 
1830 		sc->sc_tba = tba;
1831 		sc->sc_tbc = tbc;
1832 	}
1833 
1834 	SET(tp->t_state, TS_BUSY);
1835 	sc->sc_tx_busy = 1;
1836 
1837 	/* Enable transmit completion interrupts if necessary. */
1838 	if (!ISSET(sc->sc_ier, IER_ETXRDY)) {
1839 		SET(sc->sc_ier, IER_ETXRDY);
1840 		CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
1841 	}
1842 
1843 	/* Output the first chunk of the contiguous buffer. */
1844 	if (!ISSET(sc->sc_hwflags, COM_HW_NO_TXPRELOAD)) {
1845 		u_int n;
1846 
1847 		n = sc->sc_tbc;
1848 		if (n > sc->sc_fifolen)
1849 			n = sc->sc_fifolen;
1850 		CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
1851 		sc->sc_tbc -= n;
1852 		sc->sc_tba += n;
1853 	}
1854 
1855 	mutex_spin_exit(&sc->sc_lock);
1856 out:
1857 	splx(s);
1858 	return;
1859 }
1860 
1861 /*
1862  * Stop output on a line.
1863  */
1864 void
1865 comstop(struct tty *tp, int flag)
1866 {
1867 	struct com_softc *sc =
1868 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
1869 
1870 	mutex_spin_enter(&sc->sc_lock);
1871 	if (ISSET(tp->t_state, TS_BUSY)) {
1872 		/* Stop transmitting at the next chunk. */
1873 		sc->sc_tbc = 0;
1874 		sc->sc_heldtbc = 0;
1875 		if (!ISSET(tp->t_state, TS_TTSTOP))
1876 			SET(tp->t_state, TS_FLUSH);
1877 	}
1878 	mutex_spin_exit(&sc->sc_lock);
1879 }
1880 
1881 void
1882 comdiag(void *arg)
1883 {
1884 	struct com_softc *sc = arg;
1885 	int overflows, floods;
1886 
1887 	mutex_spin_enter(&sc->sc_lock);
1888 	overflows = sc->sc_overflows;
1889 	sc->sc_overflows = 0;
1890 	floods = sc->sc_floods;
1891 	sc->sc_floods = 0;
1892 	sc->sc_errors = 0;
1893 	mutex_spin_exit(&sc->sc_lock);
1894 
1895 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
1896 	    device_xname(sc->sc_dev),
1897 	    overflows, overflows == 1 ? "" : "s",
1898 	    floods, floods == 1 ? "" : "s");
1899 }
1900 
1901 integrate void
1902 com_rxsoft(struct com_softc *sc, struct tty *tp)
1903 {
1904 	int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
1905 	u_char *get, *end;
1906 	u_int cc, scc;
1907 	u_char lsr;
1908 	int code;
1909 
1910 	end = sc->sc_ebuf;
1911 	get = sc->sc_rbget;
1912 	scc = cc = com_rbuf_size - sc->sc_rbavail;
1913 
1914 	if (cc == com_rbuf_size) {
1915 		sc->sc_floods++;
1916 		if (sc->sc_errors++ == 0)
1917 			callout_reset(&sc->sc_diag_callout, 60 * hz,
1918 			    comdiag, sc);
1919 	}
1920 
1921 	/* If not yet open, drop the entire buffer content here */
1922 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
1923 		get += cc << 1;
1924 		if (get >= end)
1925 			get -= com_rbuf_size << 1;
1926 		cc = 0;
1927 	}
1928 	while (cc) {
1929 		code = get[0];
1930 		lsr = get[1];
1931 		if (ISSET(lsr, LSR_OE | LSR_BI | LSR_FE | LSR_PE)) {
1932 			if (ISSET(lsr, LSR_OE)) {
1933 				sc->sc_overflows++;
1934 				if (sc->sc_errors++ == 0)
1935 					callout_reset(&sc->sc_diag_callout,
1936 					    60 * hz, comdiag, sc);
1937 			}
1938 			if (ISSET(lsr, LSR_BI | LSR_FE))
1939 				SET(code, TTY_FE);
1940 			if (ISSET(lsr, LSR_PE))
1941 				SET(code, TTY_PE);
1942 		}
1943 		if ((*rint)(code, tp) == -1) {
1944 			/*
1945 			 * The line discipline's buffer is out of space.
1946 			 */
1947 			if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
1948 				/*
1949 				 * We're either not using flow control, or the
1950 				 * line discipline didn't tell us to block for
1951 				 * some reason.  Either way, we have no way to
1952 				 * know when there's more space available, so
1953 				 * just drop the rest of the data.
1954 				 */
1955 				get += cc << 1;
1956 				if (get >= end)
1957 					get -= com_rbuf_size << 1;
1958 				cc = 0;
1959 			} else {
1960 				/*
1961 				 * Don't schedule any more receive processing
1962 				 * until the line discipline tells us there's
1963 				 * space available (through comhwiflow()).
1964 				 * Leave the rest of the data in the input
1965 				 * buffer.
1966 				 */
1967 				SET(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
1968 			}
1969 			break;
1970 		}
1971 		get += 2;
1972 		if (get >= end)
1973 			get = sc->sc_rbuf;
1974 		cc--;
1975 	}
1976 
1977 	if (cc != scc) {
1978 		sc->sc_rbget = get;
1979 		mutex_spin_enter(&sc->sc_lock);
1980 
1981 		cc = sc->sc_rbavail += scc - cc;
1982 		/* Buffers should be ok again, release possible block. */
1983 		if (cc >= sc->sc_r_lowat) {
1984 			if (ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
1985 				CLR(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
1986 				SET(sc->sc_ier, IER_ERXRDY);
1987 				if (sc->sc_type == COM_TYPE_PXA2x0)
1988 					SET(sc->sc_ier, IER_ERXTOUT);
1989 				if (sc->sc_type == COM_TYPE_INGENIC ||
1990 				    sc->sc_type == COM_TYPE_TEGRA)
1991 					SET(sc->sc_ier, IER_ERXTOUT);
1992 
1993 				CSR_WRITE_1(&sc->sc_regs, COM_REG_IER,
1994 				    sc->sc_ier);
1995 			}
1996 			if (ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED)) {
1997 				CLR(sc->sc_rx_flags, RX_IBUF_BLOCKED);
1998 				com_hwiflow(sc);
1999 			}
2000 		}
2001 		mutex_spin_exit(&sc->sc_lock);
2002 	}
2003 }
2004 
2005 integrate void
2006 com_txsoft(struct com_softc *sc, struct tty *tp)
2007 {
2008 
2009 	CLR(tp->t_state, TS_BUSY);
2010 	if (ISSET(tp->t_state, TS_FLUSH))
2011 		CLR(tp->t_state, TS_FLUSH);
2012 	else
2013 		ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
2014 	(*tp->t_linesw->l_start)(tp);
2015 }
2016 
2017 integrate void
2018 com_stsoft(struct com_softc *sc, struct tty *tp)
2019 {
2020 	u_char msr, delta;
2021 
2022 	mutex_spin_enter(&sc->sc_lock);
2023 	msr = sc->sc_msr;
2024 	delta = sc->sc_msr_delta;
2025 	sc->sc_msr_delta = 0;
2026 	mutex_spin_exit(&sc->sc_lock);
2027 
2028 	if (ISSET(delta, sc->sc_msr_dcd)) {
2029 		/*
2030 		 * Inform the tty layer that carrier detect changed.
2031 		 */
2032 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(msr, MSR_DCD));
2033 	}
2034 
2035 	if (ISSET(delta, sc->sc_msr_cts)) {
2036 		/* Block or unblock output according to flow control. */
2037 		if (ISSET(msr, sc->sc_msr_cts)) {
2038 			sc->sc_tx_stopped = 0;
2039 			(*tp->t_linesw->l_start)(tp);
2040 		} else {
2041 			sc->sc_tx_stopped = 1;
2042 		}
2043 	}
2044 
2045 #ifdef COM_DEBUG
2046 	if (com_debug)
2047 		comstatus(sc, "com_stsoft");
2048 #endif
2049 }
2050 
2051 void
2052 comsoft(void *arg)
2053 {
2054 	struct com_softc *sc = arg;
2055 	struct tty *tp;
2056 
2057 	if (COM_ISALIVE(sc) == 0)
2058 		return;
2059 
2060 	tp = sc->sc_tty;
2061 
2062 	if (sc->sc_rx_ready) {
2063 		sc->sc_rx_ready = 0;
2064 		com_rxsoft(sc, tp);
2065 	}
2066 
2067 	if (sc->sc_st_check) {
2068 		sc->sc_st_check = 0;
2069 		com_stsoft(sc, tp);
2070 	}
2071 
2072 	if (sc->sc_tx_done) {
2073 		sc->sc_tx_done = 0;
2074 		com_txsoft(sc, tp);
2075 	}
2076 }
2077 
2078 int
2079 comintr(void *arg)
2080 {
2081 	struct com_softc *sc = arg;
2082 	struct com_regs *regsp = &sc->sc_regs;
2083 
2084 	u_char *put, *end;
2085 	u_int cc;
2086 	u_char lsr, iir;
2087 
2088 	if (COM_ISALIVE(sc) == 0)
2089 		return (0);
2090 
2091 	KASSERT(regsp != NULL);
2092 
2093 	mutex_spin_enter(&sc->sc_lock);
2094 	iir = CSR_READ_1(regsp, COM_REG_IIR);
2095 
2096 	/* Handle ns16750-specific busy interrupt. */
2097 	if (sc->sc_type == COM_TYPE_16750 &&
2098 	    (iir & IIR_BUSY) == IIR_BUSY) {
2099 		for (int timeout = 10000;
2100 		    (CSR_READ_1(regsp, COM_REG_USR) & 0x1) != 0; timeout--)
2101 			if (timeout <= 0) {
2102 				aprint_error_dev(sc->sc_dev,
2103 				    "timeout while waiting for BUSY interrupt "
2104 				    "acknowledge\n");
2105 				mutex_spin_exit(&sc->sc_lock);
2106 				return (0);
2107 			}
2108 
2109 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2110 		iir = CSR_READ_1(regsp, COM_REG_IIR);
2111 	}
2112 
2113 	/* DesignWare APB UART BUSY interrupt */
2114 	if (sc->sc_type == COM_TYPE_DW_APB &&
2115 	    (iir & IIR_BUSY) == IIR_BUSY) {
2116 		if ((CSR_READ_1(regsp, COM_REG_USR) & 0x1) != 0) {
2117 			CSR_WRITE_1(regsp, COM_REG_HALT, HALT_CHCFG_EN);
2118 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
2119 			CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
2120 			CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
2121 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2122 			CSR_WRITE_1(regsp, COM_REG_HALT,
2123 			    HALT_CHCFG_EN | HALT_CHCFG_UD);
2124 			for (int timeout = 10000000;
2125 			    (CSR_READ_1(regsp, COM_REG_HALT) & HALT_CHCFG_UD) != 0;
2126 			    timeout--) {
2127 				if (timeout <= 0) {
2128 					aprint_error_dev(sc->sc_dev,
2129 					    "timeout while waiting for HALT "
2130 					    "update acknowledge 0x%x 0x%x\n",
2131 					    CSR_READ_1(regsp, COM_REG_HALT),
2132 					    CSR_READ_1(regsp, COM_REG_USR));
2133 					break;
2134 				}
2135 			}
2136 			CSR_WRITE_1(regsp, COM_REG_HALT, 0);
2137 			(void)CSR_READ_1(regsp, COM_REG_USR);
2138 		} else {
2139 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
2140 			CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
2141 			CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
2142 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
2143 		}
2144 	}
2145 
2146 	if (ISSET(iir, IIR_NOPEND)) {
2147 		mutex_spin_exit(&sc->sc_lock);
2148 		return (0);
2149 	}
2150 
2151 	end = sc->sc_ebuf;
2152 	put = sc->sc_rbput;
2153 	cc = sc->sc_rbavail;
2154 
2155 again:	do {
2156 		u_char	msr, delta;
2157 
2158 		lsr = CSR_READ_1(regsp, COM_REG_LSR);
2159 		if (ISSET(lsr, LSR_BI)) {
2160 			int cn_trapped = 0; /* see above: cn_trap() */
2161 
2162 			cn_check_magic(sc->sc_tty->t_dev,
2163 				       CNC_BREAK, com_cnm_state);
2164 			if (cn_trapped)
2165 				continue;
2166 #if defined(KGDB) && !defined(DDB)
2167 			if (ISSET(sc->sc_hwflags, COM_HW_KGDB)) {
2168 				kgdb_connect(1);
2169 				continue;
2170 			}
2171 #endif
2172 		}
2173 
2174 		if (sc->sc_type == COM_TYPE_BCMAUXUART && ISSET(iir, IIR_RXRDY))
2175 			lsr |= LSR_RXRDY;
2176 
2177 		if (ISSET(lsr, LSR_RCV_MASK) &&
2178 		    !ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
2179 			while (cc > 0) {
2180 				int cn_trapped = 0;
2181 				put[0] = CSR_READ_1(regsp, COM_REG_RXDATA);
2182 				put[1] = lsr;
2183 				cn_check_magic(sc->sc_tty->t_dev,
2184 					       put[0], com_cnm_state);
2185 				if (cn_trapped)
2186 					goto next;
2187 				put += 2;
2188 				if (put >= end)
2189 					put = sc->sc_rbuf;
2190 				cc--;
2191 			next:
2192 				lsr = CSR_READ_1(regsp, COM_REG_LSR);
2193 				if (!ISSET(lsr, LSR_RCV_MASK))
2194 					break;
2195 			}
2196 
2197 			/*
2198 			 * Current string of incoming characters ended because
2199 			 * no more data was available or we ran out of space.
2200 			 * Schedule a receive event if any data was received.
2201 			 * If we're out of space, turn off receive interrupts.
2202 			 */
2203 			sc->sc_rbput = put;
2204 			sc->sc_rbavail = cc;
2205 			if (!ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED))
2206 				sc->sc_rx_ready = 1;
2207 
2208 			/*
2209 			 * See if we are in danger of overflowing a buffer. If
2210 			 * so, use hardware flow control to ease the pressure.
2211 			 */
2212 			if (!ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED) &&
2213 			    cc < sc->sc_r_hiwat) {
2214 				SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
2215 				com_hwiflow(sc);
2216 			}
2217 
2218 			/*
2219 			 * If we're out of space, disable receive interrupts
2220 			 * until the queue has drained a bit.
2221 			 */
2222 			if (!cc) {
2223 				SET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
2224 				switch (sc->sc_type) {
2225 				case COM_TYPE_PXA2x0:
2226 					CLR(sc->sc_ier, IER_ERXRDY|IER_ERXTOUT);
2227 					break;
2228 				case COM_TYPE_INGENIC:
2229 				case COM_TYPE_TEGRA:
2230 					CLR(sc->sc_ier,
2231 					    IER_ERXRDY | IER_ERXTOUT);
2232 					break;
2233 				default:
2234 					CLR(sc->sc_ier, IER_ERXRDY);
2235 					break;
2236 				}
2237 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
2238 			}
2239 		} else {
2240 			if ((iir & (IIR_RXRDY|IIR_TXRDY)) == IIR_RXRDY) {
2241 				(void) CSR_READ_1(regsp, COM_REG_RXDATA);
2242 				continue;
2243 			}
2244 		}
2245 
2246 		msr = CSR_READ_1(regsp, COM_REG_MSR);
2247 		delta = msr ^ sc->sc_msr;
2248 		sc->sc_msr = msr;
2249 		if ((sc->sc_pps_state.ppsparam.mode & PPS_CAPTUREBOTH) &&
2250 		    (delta & MSR_DCD)) {
2251 			mutex_spin_enter(&timecounter_lock);
2252 			pps_capture(&sc->sc_pps_state);
2253 			pps_event(&sc->sc_pps_state,
2254 			    (msr & MSR_DCD) ?
2255 			    PPS_CAPTUREASSERT :
2256 			    PPS_CAPTURECLEAR);
2257 			mutex_spin_exit(&timecounter_lock);
2258 		}
2259 
2260 		/*
2261 		 * Process normal status changes
2262 		 */
2263 		if (ISSET(delta, sc->sc_msr_mask)) {
2264 			SET(sc->sc_msr_delta, delta);
2265 
2266 			/*
2267 			 * Stop output immediately if we lose the output
2268 			 * flow control signal or carrier detect.
2269 			 */
2270 			if (ISSET(~msr, sc->sc_msr_mask)) {
2271 				sc->sc_tbc = 0;
2272 				sc->sc_heldtbc = 0;
2273 #ifdef COM_DEBUG
2274 				if (com_debug)
2275 					comstatus(sc, "comintr  ");
2276 #endif
2277 			}
2278 
2279 			sc->sc_st_check = 1;
2280 		}
2281 	} while (!ISSET((iir =
2282 	    CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND) &&
2283 	    /*
2284 	     * Since some device (e.g., ST16C1550) doesn't clear IIR_TXRDY
2285 	     * by IIR read, so we can't do this way: `process all interrupts,
2286 	     * then do TX if possible'.
2287 	     */
2288 	    (iir & IIR_IMASK) != IIR_TXRDY);
2289 
2290 	/*
2291 	 * Read LSR again, since there may be an interrupt between
2292 	 * the last LSR read and IIR read above.
2293 	 */
2294 	lsr = CSR_READ_1(regsp, COM_REG_LSR);
2295 
2296 	/*
2297 	 * See if data can be transmitted as well.
2298 	 * Schedule tx done event if no data left
2299 	 * and tty was marked busy.
2300 	 */
2301 	if (ISSET(lsr, LSR_TXRDY)) {
2302 		/*
2303 		 * If we've delayed a parameter change, do it now, and restart
2304 		 * output.
2305 		 */
2306 		if (sc->sc_heldchange) {
2307 			com_loadchannelregs(sc);
2308 			sc->sc_heldchange = 0;
2309 			sc->sc_tbc = sc->sc_heldtbc;
2310 			sc->sc_heldtbc = 0;
2311 		}
2312 
2313 		/* Output the next chunk of the contiguous buffer, if any. */
2314 		if (sc->sc_tbc > 0) {
2315 			u_int n;
2316 
2317 			n = sc->sc_tbc;
2318 			if (n > sc->sc_fifolen)
2319 				n = sc->sc_fifolen;
2320 			CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
2321 			sc->sc_tbc -= n;
2322 			sc->sc_tba += n;
2323 		} else {
2324 			/* Disable transmit completion interrupts if necessary. */
2325 			if (ISSET(sc->sc_ier, IER_ETXRDY)) {
2326 				CLR(sc->sc_ier, IER_ETXRDY);
2327 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
2328 			}
2329 			if (sc->sc_tx_busy) {
2330 				sc->sc_tx_busy = 0;
2331 				sc->sc_tx_done = 1;
2332 			}
2333 		}
2334 	}
2335 
2336 	if (!ISSET((iir = CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND))
2337 		goto again;
2338 
2339 	mutex_spin_exit(&sc->sc_lock);
2340 
2341 	/* Wake up the poller. */
2342 	softint_schedule(sc->sc_si);
2343 
2344 #ifdef RND_COM
2345 	rnd_add_uint32(&sc->rnd_source, iir | lsr);
2346 #endif
2347 
2348 	return (1);
2349 }
2350 
2351 /*
2352  * The following functions are polled getc and putc routines, shared
2353  * by the console and kgdb glue.
2354  *
2355  * The read-ahead code is so that you can detect pending in-band
2356  * cn_magic in polled mode while doing output rather than having to
2357  * wait until the kernel decides it needs input.
2358  */
2359 
2360 #define MAX_READAHEAD	20
2361 static int com_readahead[MAX_READAHEAD];
2362 static int com_readaheadcount = 0;
2363 
2364 int
2365 com_common_getc(dev_t dev, struct com_regs *regsp)
2366 {
2367 	int s = splserial();
2368 	u_char stat, c;
2369 
2370 	/* got a character from reading things earlier */
2371 	if (com_readaheadcount > 0) {
2372 		int i;
2373 
2374 		c = com_readahead[0];
2375 		for (i = 1; i < com_readaheadcount; i++) {
2376 			com_readahead[i-1] = com_readahead[i];
2377 		}
2378 		com_readaheadcount--;
2379 		splx(s);
2380 		return (c);
2381 	}
2382 
2383 	/* don't block until a character becomes available */
2384 	if (!ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
2385 		splx(s);
2386 		return -1;
2387 	}
2388 
2389 	c = CSR_READ_1(regsp, COM_REG_RXDATA);
2390 	stat = CSR_READ_1(regsp, COM_REG_IIR);
2391 	{
2392 		int cn_trapped = 0;	/* required by cn_trap, see above */
2393 #ifdef DDB
2394 		extern int db_active;
2395 		if (!db_active)
2396 #endif
2397 			cn_check_magic(dev, c, com_cnm_state);
2398 	}
2399 	splx(s);
2400 	return (c);
2401 }
2402 
2403 static void
2404 com_common_putc(dev_t dev, struct com_regs *regsp, int c)
2405 {
2406 	int s = splserial();
2407 	int cin, stat, timo;
2408 
2409 	if (com_readaheadcount < MAX_READAHEAD
2410 	     && ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
2411 		int cn_trapped = 0;
2412 		cin = CSR_READ_1(regsp, COM_REG_RXDATA);
2413 		stat = CSR_READ_1(regsp, COM_REG_IIR);
2414 		cn_check_magic(dev, cin, com_cnm_state);
2415 		com_readahead[com_readaheadcount++] = cin;
2416 	}
2417 
2418 	/* wait for any pending transmission to finish */
2419 	timo = 150000;
2420 	while (!ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_TXRDY) && --timo)
2421 		continue;
2422 
2423 	CSR_WRITE_1(regsp, COM_REG_TXDATA, c);
2424 	COM_BARRIER(regsp, BR | BW);
2425 
2426 	splx(s);
2427 }
2428 
2429 /*
2430  * Initialize UART for use as console or KGDB line.
2431  */
2432 int
2433 cominit(struct com_regs *regsp, int rate, int frequency, int type,
2434     tcflag_t cflag)
2435 {
2436 
2437 	if (bus_space_map(regsp->cr_iot, regsp->cr_iobase, regsp->cr_nports, 0,
2438 		&regsp->cr_ioh))
2439 		return (ENOMEM); /* ??? */
2440 
2441 	if (type == COM_TYPE_OMAP) {
2442 		/* disable before changing settings */
2443 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
2444 	}
2445 
2446 	rate = comspeed(rate, frequency, type);
2447 	if (__predict_true(rate != -1)) {
2448 		if (type == COM_TYPE_AU1x00) {
2449 			CSR_WRITE_2(regsp, COM_REG_DLBL, rate);
2450 		} else {
2451 			/* no EFR on alchemy */
2452 			if ((type != COM_TYPE_16550_NOERS) &&
2453 			    (type != COM_TYPE_INGENIC)) {
2454 				CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
2455 				CSR_WRITE_1(regsp, COM_REG_EFR, 0);
2456 			}
2457 			CSR_WRITE_1(regsp, COM_REG_LCR, LCR_DLAB);
2458 			CSR_WRITE_1(regsp, COM_REG_DLBL, rate & 0xff);
2459 			CSR_WRITE_1(regsp, COM_REG_DLBH, rate >> 8);
2460 		}
2461 	}
2462 	CSR_WRITE_1(regsp, COM_REG_LCR, cflag2lcr(cflag));
2463 	CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2464 
2465 	if (type == COM_TYPE_INGENIC) {
2466 		CSR_WRITE_1(regsp, COM_REG_FIFO,
2467 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
2468 		    FIFO_TRIGGER_1 | FIFO_UART_ON);
2469 	} else {
2470 		CSR_WRITE_1(regsp, COM_REG_FIFO,
2471 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
2472 		    FIFO_TRIGGER_1);
2473 	}
2474 
2475 	if (type == COM_TYPE_OMAP) {
2476 		/* setup the fifos.  the FCR value is not used as long
2477 		   as SCR[6] and SCR[7] are 0, which they are at reset
2478 		   and we never touch the SCR register */
2479 		uint8_t rx_fifo_trig = 40;
2480 		uint8_t tx_fifo_trig = 60;
2481 		uint8_t rx_start = 8;
2482 		uint8_t rx_halt = 60;
2483 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
2484 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
2485 
2486 		/* enable access to TCR & TLR */
2487 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS | MCR_TCR_TLR);
2488 
2489 		/* write tcr and tlr values */
2490 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
2491 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
2492 
2493 		/* disable access to TCR & TLR */
2494 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
2495 
2496 		/* enable again, but mode is based on speed */
2497 		if (rate > 230400) {
2498 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
2499 		} else {
2500 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
2501 		}
2502 	}
2503 
2504 	if (type == COM_TYPE_PXA2x0)
2505 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
2506 	else
2507 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
2508 
2509 	return (0);
2510 }
2511 
2512 int
2513 comcnattach1(struct com_regs *regsp, int rate, int frequency, int type,
2514     tcflag_t cflag)
2515 {
2516 	int res;
2517 
2518 	comcons_info.regs = *regsp;
2519 
2520 	res = cominit(&comcons_info.regs, rate, frequency, type, cflag);
2521 	if (res)
2522 		return (res);
2523 
2524 	cn_tab = &comcons;
2525 	cn_init_magic(&com_cnm_state);
2526 	cn_set_magic("\047\001"); /* default magic is BREAK */
2527 
2528 	comcons_info.frequency = frequency;
2529 	comcons_info.type = type;
2530 	comcons_info.rate = rate;
2531 	comcons_info.cflag = cflag;
2532 
2533 	return (0);
2534 }
2535 
2536 int
2537 comcnattach(bus_space_tag_t iot, bus_addr_t iobase, int rate, int frequency,
2538     int type, tcflag_t cflag)
2539 {
2540 	struct com_regs	regs;
2541 
2542 	/*XXX*/
2543 	bus_space_handle_t dummy_bsh;
2544 	memset(&dummy_bsh, 0, sizeof(dummy_bsh));
2545 
2546 	/*
2547 	 * dummy_bsh required because com_init_regs() wants it.  A
2548 	 * real bus_space_handle will be filled in by cominit() later.
2549 	 * XXXJRT Detangle this mess eventually, plz.
2550 	 */
2551 	com_init_regs(&regs, iot, dummy_bsh/*XXX*/, iobase);
2552 
2553 	return comcnattach1(&regs, rate, frequency, type, cflag);
2554 }
2555 
2556 static int
2557 comcnreattach(void)
2558 {
2559 	return comcnattach1(&comcons_info.regs, comcons_info.rate,
2560 	    comcons_info.frequency, comcons_info.type, comcons_info.cflag);
2561 }
2562 
2563 int
2564 comcngetc(dev_t dev)
2565 {
2566 
2567 	return (com_common_getc(dev, &comcons_info.regs));
2568 }
2569 
2570 /*
2571  * Console kernel output character routine.
2572  */
2573 void
2574 comcnputc(dev_t dev, int c)
2575 {
2576 
2577 	com_common_putc(dev, &comcons_info.regs, c);
2578 }
2579 
2580 void
2581 comcnpollc(dev_t dev, int on)
2582 {
2583 
2584 	com_readaheadcount = 0;
2585 }
2586 
2587 #ifdef KGDB
2588 int
2589 com_kgdb_attach1(struct com_regs *regsp, int rate, int frequency, int type,
2590     tcflag_t cflag)
2591 {
2592 	int res;
2593 
2594 	if (bus_space_is_equal(regsp->cr_iot, comcons_info.regs.cr_iot) &&
2595 	    regsp->cr_iobase == comcons_info.regs.cr_iobase) {
2596 #if !defined(DDB)
2597 		return (EBUSY); /* cannot share with console */
2598 #else
2599 		comkgdbregs = *regsp;
2600 		comkgdbregs.cr_ioh = comcons_info.regs.cr_ioh;
2601 #endif
2602 	} else {
2603 		comkgdbregs = *regsp;
2604 		res = cominit(&comkgdbregs, rate, frequency, type, cflag);
2605 		if (res)
2606 			return (res);
2607 
2608 		/*
2609 		 * XXXfvdl this shouldn't be needed, but the cn_magic goo
2610 		 * expects this to be initialized
2611 		 */
2612 		cn_init_magic(&com_cnm_state);
2613 		cn_set_magic("\047\001");
2614 	}
2615 
2616 	kgdb_attach(com_kgdb_getc, com_kgdb_putc, NULL);
2617 	kgdb_dev = 123; /* unneeded, only to satisfy some tests */
2618 
2619 	return (0);
2620 }
2621 
2622 int
2623 com_kgdb_attach(bus_space_tag_t iot, bus_addr_t iobase, int rate,
2624     int frequency, int type, tcflag_t cflag)
2625 {
2626 	struct com_regs regs;
2627 
2628 	com_init_regs(&regs, iot, (bus_space_handle_t)0/*XXX*/, iobase);
2629 
2630 	return com_kgdb_attach1(&regs, rate, frequency, type, cflag);
2631 }
2632 
2633 /* ARGSUSED */
2634 int
2635 com_kgdb_getc(void *arg)
2636 {
2637 
2638 	return (com_common_getc(NODEV, &comkgdbregs));
2639 }
2640 
2641 /* ARGSUSED */
2642 void
2643 com_kgdb_putc(void *arg, int c)
2644 {
2645 
2646 	com_common_putc(NODEV, &comkgdbregs, c);
2647 }
2648 #endif /* KGDB */
2649 
2650 /* helper function to identify the com ports used by
2651  console or KGDB (and not yet autoconf attached) */
2652 int
2653 com_is_console(bus_space_tag_t iot, bus_addr_t iobase, bus_space_handle_t *ioh)
2654 {
2655 	bus_space_handle_t help;
2656 
2657 	if (!comconsattached &&
2658 	    bus_space_is_equal(iot, comcons_info.regs.cr_iot) &&
2659 	    iobase == comcons_info.regs.cr_iobase)
2660 		help = comcons_info.regs.cr_ioh;
2661 #ifdef KGDB
2662 	else if (!com_kgdb_attached &&
2663 	    bus_space_is_equal(iot, comkgdbregs.cr_iot) &&
2664 	    iobase == comkgdbregs.cr_iobase)
2665 		help = comkgdbregs.cr_ioh;
2666 #endif
2667 	else
2668 		return (0);
2669 
2670 	if (ioh)
2671 		*ioh = help;
2672 	return (1);
2673 }
2674 
2675 /*
2676  * this routine exists to serve as a shutdown hook for systems that
2677  * have firmware which doesn't interact properly with a com device in
2678  * FIFO mode.
2679  */
2680 bool
2681 com_cleanup(device_t self, int how)
2682 {
2683 	struct com_softc *sc = device_private(self);
2684 
2685 	if (ISSET(sc->sc_hwflags, COM_HW_FIFO))
2686 		CSR_WRITE_1(&sc->sc_regs, COM_REG_FIFO, 0);
2687 
2688 	return true;
2689 }
2690 
2691 bool
2692 com_suspend(device_t self, const pmf_qual_t *qual)
2693 {
2694 	struct com_softc *sc = device_private(self);
2695 
2696 #if 0
2697 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE) && cn_tab == &comcons)
2698 		cn_tab = &comcons_suspend;
2699 #endif
2700 
2701 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, 0);
2702 	(void)CSR_READ_1(&sc->sc_regs, COM_REG_IIR);
2703 
2704 	return true;
2705 }
2706 
2707 bool
2708 com_resume(device_t self, const pmf_qual_t *qual)
2709 {
2710 	struct com_softc *sc = device_private(self);
2711 
2712 	mutex_spin_enter(&sc->sc_lock);
2713 	com_loadchannelregs(sc);
2714 	mutex_spin_exit(&sc->sc_lock);
2715 
2716 	return true;
2717 }
2718