xref: /dflybsd-src/sys/dev/misc/dcons/dcons_os.c (revision 744c01d0dc2aa1481a40e5b0988d15691602f5c9)
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: src/sys/dev/dcons/dcons_os.c,v 1.4 2004/10/24 12:41:04 simokawa Exp $
35  * $DragonFly: src/sys/dev/misc/dcons/dcons_os.c,v 1.10 2007/01/06 08:34:51 dillon Exp $
36  */
37 
38 #include <sys/param.h>
39 #if __FreeBSD_version >= 502122
40 #include <sys/kdb.h>
41 #include <gdb/gdb.h>
42 #endif
43 #include <sys/kernel.h>
44 #include <sys/module.h>
45 #include <sys/systm.h>
46 #include <sys/types.h>
47 #include <sys/conf.h>
48 #include <sys/cons.h>
49 #include <sys/consio.h>
50 #include <sys/tty.h>
51 #include <sys/malloc.h>
52 #include <sys/proc.h>
53 #include <sys/thread2.h>
54 #include <sys/ucred.h>
55 #include <sys/bus.h>
56 
57 #include "dcons.h"
58 #include "dcons_os.h"
59 
60 #include <ddb/ddb.h>
61 #include <sys/reboot.h>
62 
63 #include <sys/sysctl.h>
64 
65 #include <vm/vm.h>
66 #include <vm/vm_param.h>
67 #include <vm/pmap.h>
68 
69 #include "opt_ddb.h"
70 #include "opt_comconsole.h"
71 #include "opt_dcons.h"
72 
73 #ifndef DCONS_POLL_HZ
74 #define DCONS_POLL_HZ	100
75 #endif
76 
77 #ifndef DCONS_BUF_SIZE
78 #define DCONS_BUF_SIZE (16*1024)
79 #endif
80 
81 #ifndef DCONS_FORCE_CONSOLE
82 #define DCONS_FORCE_CONSOLE	0	/* Mostly for FreeBSD-4/DragonFly */
83 #endif
84 
85 #ifndef DCONS_FORCE_GDB
86 #define DCONS_FORCE_GDB	1
87 #endif
88 
89 #if __FreeBSD_version >= 500101
90 #define CONS_NODEV	1
91 #if __FreeBSD_version < 502122
92 static struct consdev gdbconsdev;
93 #endif
94 #endif
95 
96 #define CDEV_MAJOR      184
97 
98 static d_open_t		dcons_open;
99 static d_close_t	dcons_close;
100 static d_ioctl_t	dcons_ioctl;
101 
102 static struct dev_ops dcons_ops = {
103 	{ "dcons", CDEV_MAJOR, D_TTY },
104 	.d_open =	dcons_open,
105 	.d_close =	dcons_close,
106 	.d_read =	ttyread,
107 	.d_write =	ttywrite,
108 	.d_ioctl =	dcons_ioctl,
109 	.d_poll =	ttypoll,
110 };
111 
112 #ifndef KLD_MODULE
113 static char bssbuf[DCONS_BUF_SIZE];	/* buf in bss */
114 #endif
115 
116 /* global data */
117 static struct dcons_global dg;
118 struct dcons_global *dcons_conf;
119 static int poll_hz = DCONS_POLL_HZ;
120 
121 static struct dcons_softc sc[DCONS_NPORT];
122 
123 SYSCTL_NODE(_kern, OID_AUTO, dcons, CTLFLAG_RD, 0, "Dumb Console");
124 SYSCTL_INT(_kern_dcons, OID_AUTO, poll_hz, CTLFLAG_RW, &poll_hz, 0,
125 				"dcons polling rate");
126 
127 static int drv_init = 0;
128 static struct callout dcons_callout;
129 struct dcons_buf *dcons_buf;		/* for local dconschat */
130 
131 #ifdef __DragonFly__
132 #define DEV	cdev_t
133 #define THREAD	d_thread_t
134 #elif __FreeBSD_version < 500000
135 #define DEV	cdev_t
136 #define THREAD	struct proc
137 #else
138 #define DEV	struct cdev *
139 #define THREAD	struct thread
140 #endif
141 
142 
143 static void	dcons_tty_start(struct tty *);
144 static int	dcons_tty_param(struct tty *, struct termios *);
145 static void	dcons_timeout(void *);
146 static int	dcons_drv_init(int);
147 
148 static cn_probe_t	dcons_cnprobe;
149 static cn_init_t	dcons_cninit;
150 static cn_getc_t	dcons_cngetc;
151 static cn_checkc_t 	dcons_cncheckc;
152 static cn_putc_t	dcons_cnputc;
153 
154 CONS_DRIVER(dcons, dcons_cnprobe, dcons_cninit, NULL, dcons_cngetc,
155     dcons_cncheckc, dcons_cnputc, NULL);
156 
157 #if __FreeBSD_version >= 502122
158 static gdb_probe_f dcons_dbg_probe;
159 static gdb_init_f dcons_dbg_init;
160 static gdb_term_f dcons_dbg_term;
161 static gdb_getc_f dcons_dbg_getc;
162 static gdb_checkc_f dcons_dbg_checkc;
163 static gdb_putc_f dcons_dbg_putc;
164 
165 GDB_DBGPORT(dcons, dcons_dbg_probe, dcons_dbg_init, dcons_dbg_term,
166     dcons_dbg_checkc, dcons_dbg_getc, dcons_dbg_putc);
167 
168 extern struct gdb_dbgport *gdb_cur;
169 #endif
170 
171 #if (KDB || DDB) && ALT_BREAK_TO_DEBUGGER
172 static int
173 dcons_check_break(struct dcons_softc *dc, int c)
174 {
175 	if (c < 0)
176 		return (c);
177 
178 #if __FreeBSD_version >= 502122
179 	if (kdb_alt_break(c, &dc->brk_state)) {
180 		if ((dc->flags & DC_GDB) != 0) {
181 			if (gdb_cur == &dcons_gdb_dbgport) {
182 				kdb_dbbe_select("gdb");
183 				breakpoint();
184 			}
185 		} else
186 			breakpoint();
187 	}
188 #else
189 	switch (dc->brk_state) {
190 	case STATE1:
191 		if (c == KEY_TILDE)
192 			dc->brk_state = STATE2;
193 		else
194 			dc->brk_state = STATE0;
195 		break;
196 	case STATE2:
197 		dc->brk_state = STATE0;
198 		if (c == KEY_CTRLB) {
199 #if DCONS_FORCE_GDB
200 			if (dc->flags & DC_GDB)
201 				boothowto |= RB_GDB;
202 #endif
203 			breakpoint();
204 		}
205 	}
206 	if (c == KEY_CR)
207 		dc->brk_state = STATE1;
208 #endif
209 	return (c);
210 }
211 #else
212 #define	dcons_check_break(dc, c)	(c)
213 #endif
214 
215 static int
216 dcons_os_checkc(struct dcons_softc *dc)
217 {
218 	int c;
219 
220 	if (dg.dma_tag != NULL)
221 		bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_POSTREAD);
222 
223 	c = dcons_check_break(dc, dcons_checkc(dc));
224 
225 	if (dg.dma_tag != NULL)
226 		bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_PREREAD);
227 
228 	return (c);
229 }
230 
231 static int
232 dcons_os_getc(struct dcons_softc *dc)
233 {
234 	int c;
235 
236 	while ((c = dcons_os_checkc(dc)) == -1);
237 
238 	return (c & 0xff);
239 }
240 
241 static void
242 dcons_os_putc(struct dcons_softc *dc, int c)
243 {
244 	if (dg.dma_tag != NULL)
245 		bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_POSTWRITE);
246 
247 	dcons_putc(dc, c);
248 
249 	if (dg.dma_tag != NULL)
250 		bus_dmamap_sync(dg.dma_tag, dg.dma_map, BUS_DMASYNC_PREWRITE);
251 }
252 static int
253 dcons_open(struct dev_open_args *ap)
254 {
255 	cdev_t dev = ap->a_head.a_dev;
256 	struct tty *tp;
257 	int unit, error;
258 
259 	unit = minor(dev);
260 	if (unit != 0)
261 		return (ENXIO);
262 
263 	tp = dev->si_tty = ttymalloc(dev->si_tty);
264 	tp->t_oproc = dcons_tty_start;
265 	tp->t_param = dcons_tty_param;
266 	tp->t_stop = nottystop;
267 	tp->t_dev = dev;
268 
269 	error = 0;
270 
271 	crit_enter();
272 	if ((tp->t_state & TS_ISOPEN) == 0) {
273 		tp->t_state |= TS_CARR_ON;
274 		ttychars(tp);
275 		tp->t_iflag = TTYDEF_IFLAG;
276 		tp->t_oflag = TTYDEF_OFLAG;
277 		tp->t_cflag = TTYDEF_CFLAG|CLOCAL;
278 		tp->t_lflag = TTYDEF_LFLAG;
279 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
280 		ttsetwater(tp);
281 	} else if ((tp->t_state & TS_XCLUDE) && suser_cred(ap->a_cred, 0)) {
282 		crit_exit();
283 		return (EBUSY);
284 	}
285 	crit_exit();
286 
287 #if __FreeBSD_version < 502113
288 	error = (*linesw[tp->t_line].l_open)(dev, tp);
289 #else
290 	error = ttyld_open(tp, dev);
291 #endif
292 
293 	return (error);
294 }
295 
296 static int
297 dcons_close(struct dev_close_args *ap)
298 {
299 	cdev_t dev = ap->a_head.a_dev;
300 	int	unit;
301 	struct	tty *tp;
302 
303 	unit = minor(dev);
304 	if (unit != 0)
305 		return (ENXIO);
306 
307 	tp = dev->si_tty;
308 	if (tp->t_state & TS_ISOPEN) {
309 		(*linesw[tp->t_line].l_close)(tp, ap->a_fflag);
310 		ttyclose(tp);
311 	}
312 
313 	return (0);
314 }
315 
316 static int
317 dcons_ioctl(struct dev_ioctl_args *ap)
318 {
319 	cdev_t dev = ap->a_head.a_dev;
320 	int	unit;
321 	struct	tty *tp;
322 	int	error;
323 
324 	unit = minor(dev);
325 	if (unit != 0)
326 		return (ENXIO);
327 
328 	tp = dev->si_tty;
329 	error = (*linesw[tp->t_line].l_ioctl)(tp, ap->a_cmd, ap->a_data, ap->a_fflag, ap->a_cred);
330 	if (error != ENOIOCTL)
331 		return (error);
332 
333 	error = ttioctl(tp, ap->a_cmd, ap->a_data, ap->a_fflag);
334 	if (error != ENOIOCTL)
335 		return (error);
336 
337 	return (ENOTTY);
338 }
339 
340 static int
341 dcons_tty_param(struct tty *tp, struct termios *t)
342 {
343 	tp->t_ispeed = t->c_ispeed;
344 	tp->t_ospeed = t->c_ospeed;
345 	tp->t_cflag = t->c_cflag;
346 	return 0;
347 }
348 
349 static void
350 dcons_tty_start(struct tty *tp)
351 {
352 	struct dcons_softc *dc;
353 
354 	dc = (struct dcons_softc *)tp->t_dev->si_drv1;
355 	crit_enter();
356 	if (tp->t_state & (TS_TIMEOUT | TS_TTSTOP)) {
357 		ttwwakeup(tp);
358 		return;
359 	}
360 
361 	tp->t_state |= TS_BUSY;
362 	while (tp->t_outq.c_cc != 0)
363 		dcons_os_putc(dc, clist_getc(&tp->t_outq));
364 	tp->t_state &= ~TS_BUSY;
365 
366 	ttwwakeup(tp);
367 	crit_exit();
368 }
369 
370 static void
371 dcons_timeout(void *v)
372 {
373 	struct	tty *tp;
374 	struct dcons_softc *dc;
375 	int i, c, polltime;
376 
377 	for (i = 0; i < DCONS_NPORT; i ++) {
378 		dc = &sc[i];
379 		tp = ((DEV)dc->dev)->si_tty;
380 		while ((c = dcons_os_checkc(dc)) != -1)
381 			if (tp->t_state & TS_ISOPEN)
382 #if __FreeBSD_version < 502113
383 				(*linesw[tp->t_line].l_rint)(c, tp);
384 #else
385 				ttyld_rint(tp, c);
386 #endif
387 	}
388 	polltime = hz / poll_hz;
389 	if (polltime < 1)
390 		polltime = 1;
391 	callout_reset(&dcons_callout, polltime, dcons_timeout, tp);
392 }
393 
394 static void
395 dcons_cnprobe(struct consdev *cp)
396 {
397 #ifdef __DragonFly__
398 	cp->cn_dev = make_dev(&dcons_ops, DCONS_CON,
399 	    UID_ROOT, GID_WHEEL, 0600, "dcons");
400 #elif __FreeBSD_version >= 501109
401 	ksprintf(cp->cn_name, "dcons");
402 #else
403 	cp->cn_dev = makedev(CDEV_MAJOR, DCONS_CON);
404 #endif
405 #if DCONS_FORCE_CONSOLE
406 	cp->cn_pri = CN_REMOTE;
407 #else
408 	cp->cn_pri = CN_NORMAL;
409 #endif
410 }
411 
412 static void
413 dcons_cninit(struct consdev *cp)
414 {
415 	dcons_drv_init(0);
416 #if CONS_NODEV
417 	cp->cn_arg
418 #else
419 	cp->cn_dev->si_drv1
420 #endif
421 		= (void *)&sc[DCONS_CON]; /* share port0 with unit0 */
422 }
423 
424 #if CONS_NODEV
425 static int
426 dcons_cngetc(struct consdev *cp)
427 {
428 	struct dcons_softc *dc = (struct dcons_softc *)cp->cn_arg;
429 	return (dcons_os_getc(dc));
430 }
431 static int
432 dcons_cncheckc(struct consdev *cp)
433 {
434 	struct dcons_softc *dc = (struct dcons_softc *)cp->cn_arg;
435 	return (dcons_os_checkc(dc));
436 }
437 static void
438 dcons_cnputc(struct consdev *cp, int c)
439 {
440 	struct dcons_softc *dc = (struct dcons_softc *)cp->cn_arg;
441 	dcons_os_putc(dc, c);
442 }
443 #else
444 static int
445 dcons_cngetc(DEV dev)
446 {
447 	struct dcons_softc *dc = (struct dcons_softc *)dev->si_drv1;
448 	return (dcons_os_getc(dc));
449 }
450 static int
451 dcons_cncheckc(DEV dev)
452 {
453 	struct dcons_softc *dc = (struct dcons_softc *)dev->si_drv1;
454 	return (dcons_os_checkc(dc));
455 }
456 static void
457 dcons_cnputc(DEV dev, int c)
458 {
459 	struct dcons_softc *dc = (struct dcons_softc *)dev->si_drv1;
460 	dcons_os_putc(dc, c);
461 }
462 #endif
463 
464 static int
465 dcons_drv_init(int stage)
466 {
467 #ifdef __i386__
468 	quad_t addr, size;
469 #endif
470 
471 	if (drv_init)
472 		return(drv_init);
473 
474 	drv_init = -1;
475 
476 	bzero(&dg, sizeof(dg));
477 	dcons_conf = &dg;
478 	dg.cdev = &dcons_consdev;
479 	dg.buf = NULL;
480 	dg.size = DCONS_BUF_SIZE;
481 
482 #ifdef __i386__
483 	if (kgetenv_quad("dcons.addr", &addr) > 0 &&
484 	    kgetenv_quad("dcons.size", &size) > 0) {
485 		vm_paddr_t pa;
486 		/*
487 		 * Allow read/write access to dcons buffer.
488 		 */
489 		for (pa = trunc_page(addr); pa < addr + size; pa += PAGE_SIZE)
490 			pmap_kmodify_rw((vm_offset_t)(KERNBASE + pa));
491 		cpu_invltlb();
492 		/* XXX P to V */
493 		dg.buf = (struct dcons_buf *)(vm_offset_t)(KERNBASE + addr);
494 		dg.size = size;
495 		if (dcons_load_buffer(dg.buf, dg.size, sc) < 0)
496 			dg.buf = NULL;
497 	}
498 #endif
499 	if (dg.buf != NULL)
500 		goto ok;
501 
502 #ifndef KLD_MODULE
503 	if (stage == 0) { /* XXX or cold */
504 		/*
505 		 * DCONS_FORCE_CONSOLE == 1 and statically linked.
506 		 * called from cninit(). can't use contigmalloc yet .
507 		 */
508 		dg.buf = (struct dcons_buf *) bssbuf;
509 		dcons_init(dg.buf, dg.size, sc);
510 	} else
511 #endif
512 	{
513 		/*
514 		 * DCONS_FORCE_CONSOLE == 0 or kernel module case.
515 		 * if the module is loaded after boot,
516 		 * bssbuf could be non-continuous.
517 		 */
518 		dg.buf = (struct dcons_buf *) contigmalloc(dg.size,
519 			M_DEVBUF, 0, 0x10000, 0xffffffff, PAGE_SIZE, 0ul);
520 		dcons_init(dg.buf, dg.size, sc);
521 	}
522 
523 ok:
524 	dcons_buf = dg.buf;
525 
526 #if __FreeBSD_version < 502122
527 #if DDB && DCONS_FORCE_GDB
528 #if CONS_NODEV
529 	gdbconsdev.cn_arg = (void *)&sc[DCONS_GDB];
530 #if __FreeBSD_version >= 501109
531 	ksprintf(gdbconsdev.cn_name, "dgdb");
532 #endif
533 	gdb_arg = &gdbconsdev;
534 #elif defined(__DragonFly__)
535 	gdbdev = make_dev(&dcons_ops, DCONS_GDB,
536 	    UID_ROOT, GID_WHEEL, 0600, "dgdb");
537 #else
538 	gdbdev = makedev(CDEV_MAJOR, DCONS_GDB);
539 #endif
540 	gdb_getc = dcons_cngetc;
541 	gdb_putc = dcons_cnputc;
542 #endif
543 #endif
544 	drv_init = 1;
545 
546 	return 0;
547 }
548 
549 
550 static int
551 dcons_attach_port(int port, char *name, int flags)
552 {
553 	struct dcons_softc *dc;
554 	struct tty *tp;
555 	DEV dev;
556 
557 	dc = &sc[port];
558 	dc->flags = flags;
559 	dev = make_dev(&dcons_ops, port,
560 			UID_ROOT, GID_WHEEL, 0600, name);
561 	dc->dev = (void *)dev;
562 	tp = ttymalloc(NULL);
563 
564 	dev->si_drv1 = (void *)dc;
565 	dev->si_tty = tp;
566 
567 	tp->t_oproc = dcons_tty_start;
568 	tp->t_param = dcons_tty_param;
569 	tp->t_stop = nottystop;
570 	tp->t_dev = dc->dev;
571 
572 	return(0);
573 }
574 
575 static int
576 dcons_attach(void)
577 {
578 	int polltime;
579 
580 #ifdef __DragonFly__
581 	dev_ops_add(&dcons_ops, -1, 0);
582 #endif
583 	dcons_attach_port(DCONS_CON, "dcons", 0);
584 	dcons_attach_port(DCONS_GDB, "dgdb", DC_GDB);
585 #if __FreeBSD_version < 500000
586 	callout_init(&dcons_callout);
587 #else
588 	callout_init(&dcons_callout, 0);
589 #endif
590 	polltime = hz / poll_hz;
591 	if (polltime < 1)
592 		polltime = 1;
593 	callout_reset(&dcons_callout, polltime, dcons_timeout, NULL);
594 	return(0);
595 }
596 
597 static int
598 dcons_detach(int port)
599 {
600 	struct	tty *tp;
601 	struct dcons_softc *dc;
602 
603 	dc = &sc[port];
604 
605 	tp = ((DEV)dc->dev)->si_tty;
606 
607 	if (tp->t_state & TS_ISOPEN) {
608 		kprintf("dcons: still opened\n");
609 #if __FreeBSD_version < 502113
610 		(*linesw[tp->t_line].l_close)(tp, 0);
611 		tp->t_gen++;
612 		ttyclose(tp);
613 		ttwakeup(tp);
614 		ttwwakeup(tp);
615 #else
616 		ttyld_close(tp, 0);
617 		tty_close(tp);
618 #endif
619 	}
620 	/* XXX
621 	 * must wait until all device are closed.
622 	 */
623 #ifdef __DragonFly__
624 	tsleep((void *)dc, 0, "dcodtc", hz/4);
625 #else
626 	tsleep((void *)dc, PWAIT, "dcodtc", hz/4);
627 #endif
628 	destroy_dev(dc->dev);
629 
630 	return(0);
631 }
632 
633 
634 /* cnXXX works only for FreeBSD-5 */
635 static int
636 dcons_modevent(module_t mode, int type, void *data)
637 {
638 	int err = 0, ret;
639 
640 	switch (type) {
641 	case MOD_LOAD:
642 		ret = dcons_drv_init(1);
643 		dcons_attach();
644 #if __FreeBSD_version >= 500000
645 		if (ret == 0) {
646 			dcons_cnprobe(&dcons_consdev);
647 			dcons_cninit(&dcons_consdev);
648 			cnadd(&dcons_consdev);
649 		}
650 #endif
651 		break;
652 	case MOD_UNLOAD:
653 		kprintf("dcons: unload\n");
654 		callout_stop(&dcons_callout);
655 #if __FreeBSD_version < 502122
656 #if DDB && DCONS_FORCE_GDB
657 #if CONS_NODEV
658 		gdb_arg = NULL;
659 #else
660 		gdbdev = NULL;
661 #endif
662 #endif
663 #endif
664 #if __FreeBSD_version >= 500000
665 		cnremove(&dcons_consdev);
666 #endif
667 		dcons_detach(DCONS_CON);
668 		dcons_detach(DCONS_GDB);
669 		dg.buf->magic = 0;
670 
671 		contigfree(dg.buf, DCONS_BUF_SIZE, M_DEVBUF);
672 
673 		break;
674 	case MOD_SHUTDOWN:
675 		dg.buf->magic = 0;
676 		break;
677 	default:
678 		err = EOPNOTSUPP;
679 		break;
680 	}
681 	return(err);
682 }
683 
684 #if __FreeBSD_version >= 502122
685 /* Debugger interface */
686 
687 static int
688 dcons_dbg_probe(void)
689 {
690 	return(DCONS_FORCE_GDB);
691 }
692 
693 static void
694 dcons_dbg_init(void)
695 {
696 }
697 
698 static void
699 dcons_dbg_term(void)
700 {
701 }
702 
703 static void
704 dcons_dbg_putc(int c)
705 {
706 	struct dcons_softc *dc = &sc[DCONS_GDB];
707 	dcons_os_putc(dc, c);
708 }
709 
710 static int
711 dcons_dbg_checkc(void)
712 {
713 	struct dcons_softc *dc = &sc[DCONS_GDB];
714 	return (dcons_os_checkc(dc));
715 }
716 
717 static int
718 dcons_dbg_getc(void)
719 {
720 	struct dcons_softc *dc = &sc[DCONS_GDB];
721 	return (dcons_os_getc(dc));
722 }
723 #endif
724 
725 DEV_MODULE(dcons, dcons_modevent, NULL);
726 MODULE_VERSION(dcons, DCONS_VERSION);
727