xref: /freebsd/sys/dev/dcons/dcons_os.c (revision f0a75d274af375d15b97b830966b99a02b7db911)
1 /*-
2  * Copyright (C) 2003,2004
3  * 	Hidetoshi Shimokawa. All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *
16  *	This product includes software developed by Hidetoshi Shimokawa.
17  *
18  * 4. Neither the name of the author nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * $FreeBSD$
35  */
36 
37 #include <sys/param.h>
38 #if __FreeBSD_version >= 502122
39 #include <sys/kdb.h>
40 #include <gdb/gdb.h>
41 #endif
42 #include <sys/kernel.h>
43 #include <sys/module.h>
44 #include <sys/systm.h>
45 #include <sys/types.h>
46 #include <sys/conf.h>
47 #include <sys/cons.h>
48 #include <sys/consio.h>
49 #include <sys/tty.h>
50 #include <sys/malloc.h>
51 #include <sys/priv.h>
52 #include <sys/proc.h>
53 #include <sys/ucred.h>
54 
55 #include <machine/bus.h>
56 
57 #ifdef __DragonFly__
58 #include "dcons.h"
59 #include "dcons_os.h"
60 #else
61 #include <dev/dcons/dcons.h>
62 #include <dev/dcons/dcons_os.h>
63 #endif
64 
65 #include <ddb/ddb.h>
66 #include <sys/reboot.h>
67 
68 #include <sys/sysctl.h>
69 
70 #include <vm/vm.h>
71 #include <vm/vm_param.h>
72 #include <vm/pmap.h>
73 
74 #include "opt_ddb.h"
75 #include "opt_comconsole.h"
76 #include "opt_dcons.h"
77 
78 #ifndef DCONS_POLL_HZ
79 #define DCONS_POLL_HZ	100
80 #endif
81 
82 #ifndef DCONS_BUF_SIZE
83 #define DCONS_BUF_SIZE (16*1024)
84 #endif
85 
86 #ifndef DCONS_FORCE_CONSOLE
87 #define DCONS_FORCE_CONSOLE	0	/* Mostly for FreeBSD-4/DragonFly */
88 #endif
89 
90 #ifndef DCONS_FORCE_GDB
91 #define DCONS_FORCE_GDB	1
92 #endif
93 
94 #if __FreeBSD_version >= 500101
95 #define CONS_NODEV	1
96 #if __FreeBSD_version < 502122
97 static struct consdev gdbconsdev;
98 #endif
99 #endif
100 
101 static d_open_t		dcons_open;
102 static d_close_t	dcons_close;
103 #if defined(__DragonFly__) || __FreeBSD_version < 500104
104 static d_ioctl_t	dcons_ioctl;
105 #endif
106 
107 static struct cdevsw dcons_cdevsw = {
108 #ifdef __DragonFly__
109 #define CDEV_MAJOR      184
110 	"dcons", CDEV_MAJOR, D_TTY, NULL, 0,
111 	dcons_open, dcons_close, ttyread, ttywrite, dcons_ioctl,
112 	ttypoll, nommap, nostrategy, nodump, nopsize,
113 #elif __FreeBSD_version >= 500104
114 	.d_version =	D_VERSION,
115 	.d_open =	dcons_open,
116 	.d_close =	dcons_close,
117 	.d_name =	"dcons",
118 	.d_flags =	D_TTY | D_NEEDGIANT,
119 #else
120 #define CDEV_MAJOR      184
121 	/* open */	dcons_open,
122 	/* close */	dcons_close,
123 	/* read */	ttyread,
124 	/* write */	ttywrite,
125 	/* ioctl */	dcons_ioctl,
126 	/* poll */	ttypoll,
127 	/* mmap */	nommap,
128 	/* strategy */	nostrategy,
129 	/* name */	"dcons",
130 	/* major */	CDEV_MAJOR,
131 	/* dump */	nodump,
132 	/* psize */	nopsize,
133 	/* flags */	D_TTY,
134 #endif
135 };
136 
137 #ifndef KLD_MODULE
138 static char bssbuf[DCONS_BUF_SIZE];	/* buf in bss */
139 #endif
140 
141 /* global data */
142 static struct dcons_global dg;
143 struct dcons_global *dcons_conf;
144 static int poll_hz = DCONS_POLL_HZ;
145 
146 static struct dcons_softc sc[DCONS_NPORT];
147 
148 SYSCTL_NODE(_kern, OID_AUTO, dcons, CTLFLAG_RD, 0, "Dumb Console");
149 SYSCTL_INT(_kern_dcons, OID_AUTO, poll_hz, CTLFLAG_RW, &poll_hz, 0,
150 				"dcons polling rate");
151 
152 static int drv_init = 0;
153 static struct callout dcons_callout;
154 struct dcons_buf *dcons_buf;		/* for local dconschat */
155 
156 #ifdef __DragonFly__
157 #define DEV	dev_t
158 #define THREAD	d_thread_t
159 #elif __FreeBSD_version < 500000
160 #define DEV	dev_t
161 #define THREAD	struct proc
162 #else
163 #define DEV	struct cdev *
164 #define THREAD	struct thread
165 #endif
166 
167 
168 static void	dcons_tty_start(struct tty *);
169 static int	dcons_tty_param(struct tty *, struct termios *);
170 static void	dcons_timeout(void *);
171 static int	dcons_drv_init(int);
172 
173 static cn_probe_t	dcons_cnprobe;
174 static cn_init_t	dcons_cninit;
175 static cn_term_t	dcons_cnterm;
176 static cn_getc_t	dcons_cngetc;
177 static cn_putc_t	dcons_cnputc;
178 
179 CONSOLE_DRIVER(dcons);
180 
181 #if __FreeBSD_version >= 502122
182 static gdb_probe_f dcons_dbg_probe;
183 static gdb_init_f dcons_dbg_init;
184 static gdb_term_f dcons_dbg_term;
185 static gdb_getc_f dcons_dbg_getc;
186 static gdb_putc_f dcons_dbg_putc;
187 
188 GDB_DBGPORT(dcons, dcons_dbg_probe, dcons_dbg_init, dcons_dbg_term,
189     dcons_dbg_getc, dcons_dbg_putc);
190 
191 extern struct gdb_dbgport *gdb_cur;
192 #endif
193 
194 #if (defined(KDB) || defined(DDB)) && defined(ALT_BREAK_TO_DEBUGGER)
195 static int
196 dcons_check_break(struct dcons_softc *dc, int c)
197 {
198 	if (c < 0)
199 		return (c);
200 
201 #if __FreeBSD_version >= 502122
202 	if (kdb_alt_break(c, &dc->brk_state)) {
203 		if ((dc->flags & DC_GDB) != 0) {
204 			if (gdb_cur == &dcons_gdb_dbgport) {
205 				kdb_dbbe_select("gdb");
206 				breakpoint();
207 			}
208 		} else
209 			breakpoint();
210 	}
211 #else
212 	switch (dc->brk_state) {
213 	case STATE1:
214 		if (c == KEY_TILDE)
215 			dc->brk_state = STATE2;
216 		else
217 			dc->brk_state = STATE0;
218 		break;
219 	case STATE2:
220 		dc->brk_state = STATE0;
221 		if (c == KEY_CTRLB) {
222 #if DCONS_FORCE_GDB
223 			if (dc->flags & DC_GDB)
224 				boothowto |= RB_GDB;
225 #endif
226 			breakpoint();
227 		}
228 	}
229 	if (c == KEY_CR)
230 		dc->brk_state = STATE1;
231 #endif
232 	return (c);
233 }
234 #else
235 #define	dcons_check_break(dc, c)	(c)
236 #endif
237 
238 static int
239 dcons_os_checkc(struct dcons_softc *dc)
240 {
241 	int c;
242 
243 	if (dg.dma_tag != NULL)
244 		bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_POSTREAD);
245 
246 	c = dcons_check_break(dc, dcons_checkc(dc));
247 
248 	if (dg.dma_tag != NULL)
249 		bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_PREREAD);
250 
251 	return (c);
252 }
253 
254 static int
255 dcons_os_getc(struct dcons_softc *dc)
256 {
257 	int c;
258 
259 	while ((c = dcons_os_checkc(dc)) == -1);
260 
261 	return (c & 0xff);
262 }
263 
264 static void
265 dcons_os_putc(struct dcons_softc *dc, int c)
266 {
267 	if (dg.dma_tag != NULL)
268 		bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_POSTWRITE);
269 
270 	dcons_putc(dc, c);
271 
272 	if (dg.dma_tag != NULL)
273 		bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_PREWRITE);
274 }
275 static int
276 dcons_open(DEV dev, int flag, int mode, THREAD *td)
277 {
278 	struct tty *tp;
279 	int unit, error, s;
280 
281 	unit = minor(dev);
282 	if (unit != 0)
283 		return (ENXIO);
284 
285 	tp = dev->si_tty;
286 	tp->t_oproc = dcons_tty_start;
287 	tp->t_param = dcons_tty_param;
288 	tp->t_stop = nottystop;
289 	tp->t_dev = dev;
290 
291 	error = 0;
292 
293 	s = spltty();
294 	if ((tp->t_state & TS_ISOPEN) == 0) {
295 		tp->t_state |= TS_CARR_ON;
296 		ttyconsolemode(tp, 0);
297 	} else if ((tp->t_state & TS_XCLUDE) &&
298 	    priv_check(td, PRIV_TTY_EXCLUSIVE)) {
299 		splx(s);
300 		return (EBUSY);
301 	}
302 	splx(s);
303 
304 #if __FreeBSD_version < 502113
305 	error = (*linesw[tp->t_line].l_open)(dev, tp);
306 #else
307 	error = ttyld_open(tp, dev);
308 #endif
309 
310 	return (error);
311 }
312 
313 static int
314 dcons_close(DEV dev, int flag, int mode, THREAD *td)
315 {
316 	int	unit;
317 	struct	tty *tp;
318 
319 	unit = minor(dev);
320 	if (unit != 0)
321 		return (ENXIO);
322 
323 	tp = dev->si_tty;
324 	if (tp->t_state & TS_ISOPEN) {
325 #if __FreeBSD_version < 502113
326 		(*linesw[tp->t_line].l_close)(tp, flag);
327 		ttyclose(tp);
328 #else
329 		ttyld_close(tp, flag);
330 		tty_close(tp);
331 #endif
332 	}
333 
334 	return (0);
335 }
336 
337 #if defined(__DragonFly__) || __FreeBSD_version < 500104
338 static int
339 dcons_ioctl(DEV dev, u_long cmd, caddr_t data, int flag, THREAD *td)
340 {
341 	int	unit;
342 	struct	tty *tp;
343 	int	error;
344 
345 	unit = minor(dev);
346 	if (unit != 0)
347 		return (ENXIO);
348 
349 	tp = dev->si_tty;
350 	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, td);
351 	if (error != ENOIOCTL)
352 		return (error);
353 
354 	error = ttioctl(tp, cmd, data, flag);
355 	if (error != ENOIOCTL)
356 		return (error);
357 
358 	return (ENOTTY);
359 }
360 #endif
361 
362 static int
363 dcons_tty_param(struct tty *tp, struct termios *t)
364 {
365 	tp->t_ispeed = t->c_ispeed;
366 	tp->t_ospeed = t->c_ospeed;
367 	tp->t_cflag = t->c_cflag;
368 	return 0;
369 }
370 
371 static void
372 dcons_tty_start(struct tty *tp)
373 {
374 	struct dcons_softc *dc;
375 	int s;
376 
377 	dc = (struct dcons_softc *)tp->t_dev->si_drv1;
378 	s = spltty();
379 	if (tp->t_state & (TS_TIMEOUT | TS_TTSTOP)) {
380 		ttwwakeup(tp);
381 		return;
382 	}
383 
384 	tp->t_state |= TS_BUSY;
385 	while (tp->t_outq.c_cc != 0)
386 		dcons_os_putc(dc, getc(&tp->t_outq));
387 	tp->t_state &= ~TS_BUSY;
388 
389 	ttwwakeup(tp);
390 	splx(s);
391 }
392 
393 static void
394 dcons_timeout(void *v)
395 {
396 	struct	tty *tp;
397 	struct dcons_softc *dc;
398 	int i, c, polltime;
399 
400 	for (i = 0; i < DCONS_NPORT; i ++) {
401 		dc = &sc[i];
402 		tp = ((DEV)dc->dev)->si_tty;
403 		while ((c = dcons_os_checkc(dc)) != -1)
404 			if (tp->t_state & TS_ISOPEN)
405 #if __FreeBSD_version < 502113
406 				(*linesw[tp->t_line].l_rint)(c, tp);
407 #else
408 				ttyld_rint(tp, c);
409 #endif
410 	}
411 	polltime = hz / poll_hz;
412 	if (polltime < 1)
413 		polltime = 1;
414 	callout_reset(&dcons_callout, polltime, dcons_timeout, tp);
415 }
416 
417 static void
418 dcons_cnprobe(struct consdev *cp)
419 {
420 #ifdef __DragonFly__
421 	cp->cn_dev = make_dev(&dcons_cdevsw, DCONS_CON,
422 	    UID_ROOT, GID_WHEEL, 0600, "dcons");
423 #elif __FreeBSD_version >= 501109
424 	sprintf(cp->cn_name, "dcons");
425 #else
426 	cp->cn_dev = makedev(CDEV_MAJOR, DCONS_CON);
427 #endif
428 #if DCONS_FORCE_CONSOLE
429 	cp->cn_pri = CN_REMOTE;
430 #else
431 	cp->cn_pri = CN_NORMAL;
432 #endif
433 }
434 
435 static void
436 dcons_cninit(struct consdev *cp)
437 {
438 	dcons_drv_init(0);
439 #if CONS_NODEV
440 	cp->cn_arg
441 #else
442 	cp->cn_dev->si_drv1
443 #endif
444 		= (void *)&sc[DCONS_CON]; /* share port0 with unit0 */
445 }
446 
447 static void
448 dcons_cnterm(struct consdev *cp)
449 {
450 }
451 
452 #if CONS_NODEV
453 static int
454 dcons_cngetc(struct consdev *cp)
455 {
456 	struct dcons_softc *dc = (struct dcons_softc *)cp->cn_arg;
457 	return (dcons_os_checkc(dc));
458 }
459 static void
460 dcons_cnputc(struct consdev *cp, int c)
461 {
462 	struct dcons_softc *dc = (struct dcons_softc *)cp->cn_arg;
463 	dcons_os_putc(dc, c);
464 }
465 #else
466 static int
467 dcons_cngetc(DEV dev)
468 {
469 	struct dcons_softc *dc = (struct dcons_softc *)dev->si_drv1;
470 	return (dcons_os_getc(dc));
471 }
472 static int
473 dcons_cncheckc(DEV dev)
474 {
475 	struct dcons_softc *dc = (struct dcons_softc *)dev->si_drv1;
476 	return (dcons_os_checkc(dc));
477 }
478 static void
479 dcons_cnputc(DEV dev, int c)
480 {
481 	struct dcons_softc *dc = (struct dcons_softc *)dev->si_drv1;
482 	dcons_os_putc(dc, c);
483 }
484 #endif
485 
486 static int
487 dcons_drv_init(int stage)
488 {
489 #if defined(__i386__) || defined(__amd64__)
490 	quad_t addr, size;
491 #endif
492 
493 	if (drv_init)
494 		return(drv_init);
495 
496 	drv_init = -1;
497 
498 	bzero(&dg, sizeof(dg));
499 	dcons_conf = &dg;
500 	dg.cdev = &dcons_consdev;
501 	dg.buf = NULL;
502 	dg.size = DCONS_BUF_SIZE;
503 
504 #if defined(__i386__) || defined(__amd64__)
505 	if (getenv_quad("dcons.addr", &addr) > 0 &&
506 	    getenv_quad("dcons.size", &size) > 0) {
507 #ifdef __i386__
508 		vm_paddr_t pa;
509 		/*
510 		 * Allow read/write access to dcons buffer.
511 		 */
512 		for (pa = trunc_page(addr); pa < addr + size; pa += PAGE_SIZE)
513 			*vtopte(KERNBASE + pa) |= PG_RW;
514 		invltlb();
515 #endif
516 		/* XXX P to V */
517 		dg.buf = (struct dcons_buf *)(vm_offset_t)(KERNBASE + addr);
518 		dg.size = size;
519 		if (dcons_load_buffer(dg.buf, dg.size, sc) < 0)
520 			dg.buf = NULL;
521 	}
522 #endif
523 	if (dg.buf != NULL)
524 		goto ok;
525 
526 #ifndef KLD_MODULE
527 	if (stage == 0) { /* XXX or cold */
528 		/*
529 		 * DCONS_FORCE_CONSOLE == 1 and statically linked.
530 		 * called from cninit(). can't use contigmalloc yet .
531 		 */
532 		dg.buf = (struct dcons_buf *) bssbuf;
533 		dcons_init(dg.buf, dg.size, sc);
534 	} else
535 #endif
536 	{
537 		/*
538 		 * DCONS_FORCE_CONSOLE == 0 or kernel module case.
539 		 * if the module is loaded after boot,
540 		 * bssbuf could be non-continuous.
541 		 */
542 		dg.buf = (struct dcons_buf *) contigmalloc(dg.size,
543 			M_DEVBUF, 0, 0x10000, 0xffffffff, PAGE_SIZE, 0ul);
544 		dcons_init(dg.buf, dg.size, sc);
545 	}
546 
547 ok:
548 	dcons_buf = dg.buf;
549 
550 #if __FreeBSD_version < 502122
551 #if defined(DDB) && DCONS_FORCE_GDB
552 #if CONS_NODEV
553 	gdbconsdev.cn_arg = (void *)&sc[DCONS_GDB];
554 #if __FreeBSD_version >= 501109
555 	sprintf(gdbconsdev.cn_name, "dgdb");
556 #endif
557 	gdb_arg = &gdbconsdev;
558 #elif defined(__DragonFly__)
559 	gdbdev = make_dev(&dcons_cdevsw, DCONS_GDB,
560 	    UID_ROOT, GID_WHEEL, 0600, "dgdb");
561 #else
562 	gdbdev = makedev(CDEV_MAJOR, DCONS_GDB);
563 #endif
564 	gdb_getc = dcons_cngetc;
565 	gdb_putc = dcons_cnputc;
566 #endif
567 #endif
568 	drv_init = 1;
569 
570 	return 0;
571 }
572 
573 
574 static int
575 dcons_attach_port(int port, char *name, int flags)
576 {
577 	struct dcons_softc *dc;
578 	struct tty *tp;
579 	DEV dev;
580 
581 	dc = &sc[port];
582 	dc->flags = flags;
583 	dev = make_dev(&dcons_cdevsw, port,
584 			UID_ROOT, GID_WHEEL, 0600, name);
585 	dc->dev = (void *)dev;
586 	tp = ttyalloc();
587 
588 	dev->si_drv1 = (void *)dc;
589 	dev->si_tty = tp;
590 
591 	tp->t_oproc = dcons_tty_start;
592 	tp->t_param = dcons_tty_param;
593 	tp->t_stop = nottystop;
594 	tp->t_dev = dc->dev;
595 
596 	return(0);
597 }
598 
599 static int
600 dcons_attach(void)
601 {
602 	int polltime;
603 
604 #ifdef __DragonFly__
605 	cdevsw_add(&dcons_cdevsw, -1, 0);
606 #endif
607 	dcons_attach_port(DCONS_CON, "dcons", 0);
608 	dcons_attach_port(DCONS_GDB, "dgdb", DC_GDB);
609 #if __FreeBSD_version < 500000
610 	callout_init(&dcons_callout);
611 #else
612 	callout_init(&dcons_callout, 0);
613 #endif
614 	polltime = hz / poll_hz;
615 	if (polltime < 1)
616 		polltime = 1;
617 	callout_reset(&dcons_callout, polltime, dcons_timeout, NULL);
618 	return(0);
619 }
620 
621 static int
622 dcons_detach(int port)
623 {
624 	struct	tty *tp;
625 	struct dcons_softc *dc;
626 
627 	dc = &sc[port];
628 
629 	tp = ((DEV)dc->dev)->si_tty;
630 
631 	if (tp->t_state & TS_ISOPEN) {
632 		printf("dcons: still opened\n");
633 #if __FreeBSD_version < 502113
634 		(*linesw[tp->t_line].l_close)(tp, 0);
635 		tp->t_gen++;
636 		ttyclose(tp);
637 		ttwakeup(tp);
638 		ttwwakeup(tp);
639 #else
640 		ttyld_close(tp, 0);
641 		tty_close(tp);
642 #endif
643 	}
644 	/* XXX
645 	 * must wait until all device are closed.
646 	 */
647 #ifdef __DragonFly__
648 	tsleep((void *)dc, 0, "dcodtc", hz/4);
649 #else
650 	tsleep((void *)dc, PWAIT, "dcodtc", hz/4);
651 #endif
652 	destroy_dev(dc->dev);
653 
654 	return(0);
655 }
656 
657 
658 /* cnXXX works only for FreeBSD-5 */
659 static int
660 dcons_modevent(module_t mode, int type, void *data)
661 {
662 	int err = 0, ret;
663 
664 	switch (type) {
665 	case MOD_LOAD:
666 		ret = dcons_drv_init(1);
667 		dcons_attach();
668 #if __FreeBSD_version >= 500000
669 		if (ret == 0) {
670 			dcons_cnprobe(&dcons_consdev);
671 			dcons_cninit(&dcons_consdev);
672 			cnadd(&dcons_consdev);
673 		}
674 #endif
675 		break;
676 	case MOD_UNLOAD:
677 		printf("dcons: unload\n");
678 		callout_stop(&dcons_callout);
679 #if __FreeBSD_version < 502122
680 #if defined(DDB) && DCONS_FORCE_GDB
681 #if CONS_NODEV
682 		gdb_arg = NULL;
683 #else
684 		gdbdev = NULL;
685 #endif
686 #endif
687 #endif
688 #if __FreeBSD_version >= 500000
689 		cnremove(&dcons_consdev);
690 #endif
691 		dcons_detach(DCONS_CON);
692 		dcons_detach(DCONS_GDB);
693 		dg.buf->magic = 0;
694 
695 		contigfree(dg.buf, DCONS_BUF_SIZE, M_DEVBUF);
696 
697 		break;
698 	case MOD_SHUTDOWN:
699 		dg.buf->magic = 0;
700 		break;
701 	default:
702 		err = EOPNOTSUPP;
703 		break;
704 	}
705 	return(err);
706 }
707 
708 #if __FreeBSD_version >= 502122
709 /* Debugger interface */
710 
711 static int
712 dcons_dbg_probe(void)
713 {
714 	return(DCONS_FORCE_GDB);
715 }
716 
717 static void
718 dcons_dbg_init(void)
719 {
720 }
721 
722 static void
723 dcons_dbg_term(void)
724 {
725 }
726 
727 static void
728 dcons_dbg_putc(int c)
729 {
730 	struct dcons_softc *dc = &sc[DCONS_GDB];
731 	dcons_os_putc(dc, c);
732 }
733 
734 static int
735 dcons_dbg_getc(void)
736 {
737 	struct dcons_softc *dc = &sc[DCONS_GDB];
738 	return (dcons_os_getc(dc));
739 }
740 #endif
741 
742 DEV_MODULE(dcons, dcons_modevent, NULL);
743 MODULE_VERSION(dcons, DCONS_VERSION);
744