xref: /netbsd-src/sys/dev/usb/umct.c (revision 53d1339bf7f9c7367b35a9e1ebe693f9b047a47b)
1 /*	$NetBSD: umct.c,v 1.42 2021/04/24 23:36:59 thorpej Exp $	*/
2 /*
3  * Copyright (c) 2001 The NetBSD Foundation, Inc.
4  * All rights reserved.
5  *
6  * This code is derived from software contributed to The NetBSD Foundation
7  * by Ichiro FUKUHARA (ichiro@ichiro.org).
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
22  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  * POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 /*
32  * MCT USB-RS232 Interface Controller
33  * http://www.mct.com.tw/prod/rs232.html
34  * http://www.dlink.com/products/usb/dsbs25
35  */
36 
37 #include <sys/cdefs.h>
38 __KERNEL_RCSID(0, "$NetBSD: umct.c,v 1.42 2021/04/24 23:36:59 thorpej Exp $");
39 
40 #ifdef _KERNEL_OPT
41 #include "opt_usb.h"
42 #endif
43 
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/ioctl.h>
48 #include <sys/conf.h>
49 #include <sys/tty.h>
50 #include <sys/file.h>
51 #include <sys/select.h>
52 #include <sys/proc.h>
53 #include <sys/vnode.h>
54 #include <sys/device.h>
55 #include <sys/poll.h>
56 
57 #include <dev/usb/usb.h>
58 #include <dev/usb/usbcdc.h>
59 
60 #include <dev/usb/usbdi.h>
61 #include <dev/usb/usbdi_util.h>
62 #include <dev/usb/usbdevs.h>
63 #include <dev/usb/usb_quirks.h>
64 
65 #include <dev/usb/ucomvar.h>
66 #include <dev/usb/umct.h>
67 
68 #ifdef UMCT_DEBUG
69 #define DPRINTFN(n, x)  if (umctdebug > (n)) printf x
70 int	umctdebug = 0;
71 #else
72 #define DPRINTFN(n, x)
73 #endif
74 #define DPRINTF(x) DPRINTFN(0, x)
75 
76 #define	UMCT_CONFIG_INDEX	0
77 #define	UMCT_IFACE_INDEX	0
78 
79 struct	umct_softc {
80 	device_t		sc_dev;		/* base device */
81 	struct usbd_device *	sc_udev;	/* USB device */
82 	struct usbd_interface *	sc_iface;	/* interface */
83 	int			sc_iface_number;	/* interface number */
84 	uint16_t		sc_product;
85 
86 	int			sc_intr_number;	/* interrupt number */
87 	struct usbd_pipe *	sc_intr_pipe;	/* interrupt pipe */
88 	u_char			*sc_intr_buf;	/* interrupt buffer */
89 	int			sc_isize;
90 
91 	usb_cdc_line_state_t	sc_line_state;	/* current line state */
92 	u_char			sc_dtr;		/* current DTR state */
93 	u_char			sc_rts;		/* current RTS state */
94 	u_char			sc_break;	/* set break */
95 
96 	u_char			sc_status;
97 
98 	device_t		sc_subdev;	/* ucom device */
99 
100 	bool			sc_dying;	/* disconnecting */
101 
102 	u_char			sc_lsr;		/* Local status register */
103 	u_char			sc_msr;		/* umct status register */
104 
105 	u_int			last_lcr;	/* keep lcr register */
106 };
107 
108 /*
109  * These are the maximum number of bytes transferred per frame.
110  * The output buffer size cannot be increased due to the size encoding.
111  */
112 #define UMCTIBUFSIZE 256
113 #define UMCTOBUFSIZE 256
114 
115 static	void umct_init(struct umct_softc *);
116 static	void umct_set_baudrate(struct umct_softc *, u_int);
117 static	void umct_set_lcr(struct umct_softc *, u_int);
118 static	void umct_intr(struct usbd_xfer *, void *, usbd_status);
119 
120 static	void umct_set(void *, int, int, int);
121 static	void umct_dtr(struct umct_softc *, int);
122 static	void umct_rts(struct umct_softc *, int);
123 static	void umct_break(struct umct_softc *, int);
124 static	void umct_set_line_state(struct umct_softc *);
125 static	void umct_get_status(void *, int, u_char *, u_char *);
126 static	int  umct_param(void *, int, struct termios *);
127 static	int  umct_open(void *, int);
128 static	void umct_close(void *, int);
129 
130 static const struct	ucom_methods umct_methods = {
131 	.ucom_get_status = umct_get_status,
132 	.ucom_set = umct_set,
133 	.ucom_param = umct_param,
134 	.ucom_open = umct_open,
135 	.ucom_close = umct_close,
136 };
137 
138 static const struct usb_devno umct_devs[] = {
139 	/* MCT USB-232 Interface Products */
140 	{ USB_VENDOR_MCT, USB_PRODUCT_MCT_USB232 },
141 	/* Sitecom USB-232 Products */
142 	{ USB_VENDOR_MCT, USB_PRODUCT_MCT_SITECOM_USB232 },
143 	/* D-Link DU-H3SP USB BAY Hub Products */
144 	{ USB_VENDOR_MCT, USB_PRODUCT_MCT_DU_H3SP_USB232 },
145 	/* BELKIN F5U109 */
146 	{ USB_VENDOR_BELKIN, USB_PRODUCT_BELKIN_F5U109 },
147 };
148 #define umct_lookup(v, p) usb_lookup(umct_devs, v, p)
149 
150 static int	umct_match(device_t, cfdata_t, void *);
151 static void	umct_attach(device_t, device_t, void *);
152 static void	umct_childdet(device_t, device_t);
153 static int	umct_detach(device_t, int);
154 
155 CFATTACH_DECL2_NEW(umct, sizeof(struct umct_softc), umct_match,
156     umct_attach, umct_detach, NULL, NULL, umct_childdet);
157 
158 static int
159 umct_match(device_t parent, cfdata_t match, void *aux)
160 {
161 	struct usb_attach_arg *uaa = aux;
162 
163 	return umct_lookup(uaa->uaa_vendor, uaa->uaa_product) != NULL ?
164 		UMATCH_VENDOR_PRODUCT : UMATCH_NONE;
165 }
166 
167 static void
168 umct_attach(device_t parent, device_t self, void *aux)
169 {
170 	struct umct_softc *sc = device_private(self);
171 	struct usb_attach_arg *uaa = aux;
172 	struct usbd_device *dev = uaa->uaa_device;
173 	usb_config_descriptor_t *cdesc;
174 	usb_interface_descriptor_t *id;
175 	usb_endpoint_descriptor_t *ed;
176 
177 	char *devinfop;
178 	usbd_status err;
179 	int i;
180 	struct ucom_attach_args ucaa;
181 
182 	sc->sc_dev = self;
183 	sc->sc_dying = false;
184 
185 	aprint_naive("\n");
186 	aprint_normal("\n");
187 
188 	devinfop = usbd_devinfo_alloc(dev, 0);
189 	aprint_normal_dev(self, "%s\n", devinfop);
190 	usbd_devinfo_free(devinfop);
191 
192 	sc->sc_udev = dev;
193 	sc->sc_product = uaa->uaa_product;
194 
195 	DPRINTF(("\n\numct attach: sc=%p\n", sc));
196 
197 	/* initialize endpoints */
198 	ucaa.ucaa_bulkin = ucaa.ucaa_bulkout = -1;
199 	sc->sc_intr_number = -1;
200 	sc->sc_intr_pipe = NULL;
201 
202 	/* Move the device into the configured state. */
203 	err = usbd_set_config_index(dev, UMCT_CONFIG_INDEX, 1);
204 	if (err) {
205 		aprint_error_dev(self, "failed to set configuration, err=%s\n",
206 		    usbd_errstr(err));
207 		sc->sc_dying = true;
208 		return;
209 	}
210 
211 	/* get the config descriptor */
212 	cdesc = usbd_get_config_descriptor(sc->sc_udev);
213 
214 	if (cdesc == NULL) {
215 		aprint_error_dev(self,
216 		    "failed to get configuration descriptor\n");
217 		sc->sc_dying = true;
218 		return;
219 	}
220 
221 	/* get the interface */
222 	err = usbd_device2interface_handle(dev, UMCT_IFACE_INDEX,
223 							&sc->sc_iface);
224 	if (err) {
225 		aprint_error_dev(self, "failed to get interface, err=%s\n",
226 		    usbd_errstr(err));
227 		sc->sc_dying = true;
228 		return;
229 	}
230 
231 	/* Find the bulk{in,out} and interrupt endpoints */
232 
233 	id = usbd_get_interface_descriptor(sc->sc_iface);
234 	sc->sc_iface_number = id->bInterfaceNumber;
235 
236 	for (i = 0; i < id->bNumEndpoints; i++) {
237 		ed = usbd_interface2endpoint_descriptor(sc->sc_iface, i);
238 		if (ed == NULL) {
239 			aprint_error_dev(self,
240 			    "no endpoint descriptor for %d\n", i);
241 			sc->sc_dying = true;
242 			return;
243 		}
244 
245 		/*
246 		 * The Bulkin endpoint is marked as an interrupt. Since
247 		 * we can't rely on the endpoint descriptor order, we'll
248 		 * check the wMaxPacketSize field to differentiate.
249 		 */
250 		if (UE_GET_DIR(ed->bEndpointAddress) == UE_DIR_IN &&
251 		    UE_GET_XFERTYPE(ed->bmAttributes) == UE_INTERRUPT &&
252 		    UGETW(ed->wMaxPacketSize) != 0x2) {
253 			ucaa.ucaa_bulkin = ed->bEndpointAddress;
254 		} else if (UE_GET_DIR(ed->bEndpointAddress) == UE_DIR_OUT &&
255 		    UE_GET_XFERTYPE(ed->bmAttributes) == UE_BULK) {
256 			ucaa.ucaa_bulkout = ed->bEndpointAddress;
257 		} else if (UE_GET_DIR(ed->bEndpointAddress) == UE_DIR_IN &&
258 		    UE_GET_XFERTYPE(ed->bmAttributes) == UE_INTERRUPT) {
259 			sc->sc_intr_number = ed->bEndpointAddress;
260 			sc->sc_isize = UGETW(ed->wMaxPacketSize);
261 		}
262 	}
263 
264 	if (ucaa.ucaa_bulkin == -1) {
265 		aprint_error_dev(self, "Could not find data bulk in\n");
266 		sc->sc_dying = true;
267 		return;
268 	}
269 
270 	if (ucaa.ucaa_bulkout == -1) {
271 		aprint_error_dev(self, "Could not find data bulk out\n");
272 		sc->sc_dying = true;
273 		return;
274 	}
275 
276 	if (sc->sc_intr_number == -1) {
277 		aprint_error_dev(self, "Could not find interrupt in\n");
278 		sc->sc_dying = true;
279 		return;
280 	}
281 
282 	sc->sc_dtr = sc->sc_rts = 0;
283 	ucaa.ucaa_portno = UCOM_UNK_PORTNO;
284 	/* ucaa_bulkin, ucaa_bulkout set above */
285 	ucaa.ucaa_ibufsize = UMCTIBUFSIZE;
286 	if (sc->sc_product == USB_PRODUCT_MCT_SITECOM_USB232)
287 		ucaa.ucaa_obufsize = 16; /* device is broken */
288 	else
289 		ucaa.ucaa_obufsize = UMCTOBUFSIZE;
290 	ucaa.ucaa_ibufsizepad = UMCTIBUFSIZE;
291 	ucaa.ucaa_opkthdrlen = 0;
292 	ucaa.ucaa_device = dev;
293 	ucaa.ucaa_iface = sc->sc_iface;
294 	ucaa.ucaa_methods = &umct_methods;
295 	ucaa.ucaa_arg = sc;
296 	ucaa.ucaa_info = NULL;
297 
298 	umct_init(sc);
299 
300 	usbd_add_drv_event(USB_EVENT_DRIVER_ATTACH, sc->sc_udev, sc->sc_dev);
301 
302 	DPRINTF(("umct: in=%#x out=%#x intr=%#x\n",
303 	    ucaa.ucaa_bulkin, ucaa.ucaa_bulkout, sc->sc_intr_number));
304 	sc->sc_subdev = config_found(self, &ucaa, ucomprint,
305 				     CFARG_SUBMATCH, ucomsubmatch,
306 				     CFARG_EOL);
307 
308 	return;
309 }
310 
311 static void
312 umct_childdet(device_t self, device_t child)
313 {
314 	struct umct_softc *sc = device_private(self);
315 
316 	KASSERT(sc->sc_subdev == child);
317 	sc->sc_subdev = NULL;
318 }
319 
320 static void
321 umct_close_pipe(struct umct_softc *sc)
322 {
323 
324 	if (sc->sc_intr_pipe != NULL) {
325 		usbd_abort_pipe(sc->sc_intr_pipe);
326 		usbd_close_pipe(sc->sc_intr_pipe);
327 		sc->sc_intr_pipe = NULL;
328 	}
329 	if (sc->sc_intr_buf != NULL) {
330 		kmem_free(sc->sc_intr_buf, sc->sc_isize);
331 		sc->sc_intr_buf = NULL;
332 	}
333 }
334 
335 static int
336 umct_detach(device_t self, int flags)
337 {
338 	struct umct_softc *sc = device_private(self);
339 	int rv = 0;
340 
341 	DPRINTF(("umct_detach: sc=%p flags=%d\n", sc, flags));
342 
343 	sc->sc_dying = true;
344 
345 	umct_close_pipe(sc);
346 
347 	if (sc->sc_subdev != NULL) {
348 		rv = config_detach(sc->sc_subdev, flags);
349 		sc->sc_subdev = NULL;
350 	}
351 
352 	usbd_add_drv_event(USB_EVENT_DRIVER_DETACH, sc->sc_udev, sc->sc_dev);
353 
354 	return rv;
355 }
356 
357 static void
358 umct_set_line_state(struct umct_softc *sc)
359 {
360 	usb_device_request_t req;
361 	uByte ls;
362 
363 	ls = (sc->sc_dtr ? MCR_DTR : 0) |
364 	     (sc->sc_rts ? MCR_RTS : 0);
365 
366 	DPRINTF(("umct_set_line_state: DTR=%d,RTS=%d,ls=%02x\n",
367 			sc->sc_dtr, sc->sc_rts, ls));
368 
369 	req.bmRequestType = UMCT_SET_REQUEST;
370 	req.bRequest = REQ_SET_MCR;
371 	USETW(req.wValue, 0);
372 	USETW(req.wIndex, sc->sc_iface_number);
373 	USETW(req.wLength, LENGTH_SET_MCR);
374 
375 	(void)usbd_do_request(sc->sc_udev, &req, &ls);
376 }
377 
378 static void
379 umct_set(void *addr, int portno, int reg, int onoff)
380 {
381 	struct umct_softc *sc = addr;
382 
383 	if (sc->sc_dying)
384 		return;
385 
386 	switch (reg) {
387 	case UCOM_SET_DTR:
388 		umct_dtr(sc, onoff);
389 		break;
390 	case UCOM_SET_RTS:
391 		umct_rts(sc, onoff);
392 		break;
393 	case UCOM_SET_BREAK:
394 		umct_break(sc, onoff);
395 		break;
396 	default:
397 		break;
398 	}
399 }
400 
401 void
402 umct_dtr(struct umct_softc *sc, int onoff)
403 {
404 
405 	DPRINTF(("umct_dtr: onoff=%d\n", onoff));
406 
407 	if (sc->sc_dtr == onoff)
408 		return;
409 	sc->sc_dtr = onoff;
410 
411 	umct_set_line_state(sc);
412 }
413 
414 void
415 umct_rts(struct umct_softc *sc, int onoff)
416 {
417 	DPRINTF(("umct_rts: onoff=%d\n", onoff));
418 
419 	if (sc->sc_rts == onoff)
420 		return;
421 	sc->sc_rts = onoff;
422 
423 	umct_set_line_state(sc);
424 }
425 
426 void
427 umct_break(struct umct_softc *sc, int onoff)
428 {
429 	DPRINTF(("umct_break: onoff=%d\n", onoff));
430 
431 	umct_set_lcr(sc, onoff ? sc->last_lcr | LCR_SET_BREAK :
432 		     sc->last_lcr);
433 }
434 
435 void
436 umct_set_lcr(struct umct_softc *sc, u_int data)
437 {
438 	usb_device_request_t req;
439 	uByte adata;
440 
441 	adata = data;
442 	req.bmRequestType = UMCT_SET_REQUEST;
443 	req.bRequest = REQ_SET_LCR;
444 	USETW(req.wValue, 0);
445 	USETW(req.wIndex, sc->sc_iface_number);
446 	USETW(req.wLength, LENGTH_SET_LCR);
447 
448 	(void)usbd_do_request(sc->sc_udev, &req, &adata); /* XXX should check */
449 }
450 
451 void
452 umct_set_baudrate(struct umct_softc *sc, u_int rate)
453 {
454 	usb_device_request_t req;
455 	uDWord arate;
456 	u_int val;
457 
458 	if (sc->sc_product == USB_PRODUCT_MCT_SITECOM_USB232 ||
459 	    sc->sc_product == USB_PRODUCT_BELKIN_F5U109) {
460 		switch (rate) {
461 		case    300: val = 0x01; break;
462 		case    600: val = 0x02; break;
463 		case   1200: val = 0x03; break;
464 		case   2400: val = 0x04; break;
465 		case   4800: val = 0x06; break;
466 		case   9600: val = 0x08; break;
467 		case  19200: val = 0x09; break;
468 		case  38400: val = 0x0a; break;
469 		case  57600: val = 0x0b; break;
470 		case 115200: val = 0x0c; break;
471 		default:     val = -1; break;
472 		}
473 	} else {
474 		val = UMCT_BAUD_RATE(rate);
475 	}
476 	USETDW(arate, val);
477 
478 	req.bmRequestType = UMCT_SET_REQUEST;
479 	req.bRequest = REQ_SET_BAUD_RATE;
480 	USETW(req.wValue, 0);
481 	USETW(req.wIndex, sc->sc_iface_number);
482 	USETW(req.wLength, LENGTH_BAUD_RATE);
483 
484 	(void)usbd_do_request(sc->sc_udev, &req, arate); /* XXX should check */
485 }
486 
487 static void
488 umct_init(struct umct_softc *sc)
489 {
490 	umct_set_baudrate(sc, 9600);
491 	umct_set_lcr(sc, LCR_DATA_BITS_8 | LCR_PARITY_NONE | LCR_STOP_BITS_1);
492 }
493 
494 static int
495 umct_param(void *addr, int portno, struct termios *t)
496 {
497 	struct umct_softc *sc = addr;
498 	u_int data = 0;
499 
500 	DPRINTF(("umct_param: sc=%p BAUDRATE=%d\n", sc, t->c_ospeed));
501 
502 	if (sc->sc_dying)
503 		return EIO;
504 
505 	if (ISSET(t->c_cflag, CSTOPB))
506 		data |= LCR_STOP_BITS_2;
507 	else
508 		data |= LCR_STOP_BITS_1;
509 	if (ISSET(t->c_cflag, PARENB)) {
510 		if (ISSET(t->c_cflag, PARODD))
511 			data |= LCR_PARITY_ODD;
512 		else
513 			data |= LCR_PARITY_EVEN;
514 	} else
515 		data |= LCR_PARITY_NONE;
516 	switch (ISSET(t->c_cflag, CSIZE)) {
517 	case CS5:
518 		data |= LCR_DATA_BITS_5;
519 		break;
520 	case CS6:
521 		data |= LCR_DATA_BITS_6;
522 		break;
523 	case CS7:
524 		data |= LCR_DATA_BITS_7;
525 		break;
526 	case CS8:
527 		data |= LCR_DATA_BITS_8;
528 		break;
529 	}
530 
531 	umct_set_baudrate(sc, t->c_ospeed);
532 
533 	sc->last_lcr = data;
534 	umct_set_lcr(sc, data);
535 
536 	return 0;
537 }
538 
539 int
540 umct_open(void *addr, int portno)
541 {
542 	struct umct_softc *sc = addr;
543 	int err, lcr_data;
544 
545 	DPRINTF(("umct_open: sc=%p\n", sc));
546 
547 	if (sc->sc_dying)
548 		return EIO;
549 
550 	/* initialize LCR */
551 	lcr_data = LCR_DATA_BITS_8 | LCR_PARITY_NONE |
552 	    LCR_STOP_BITS_1;
553 	umct_set_lcr(sc, lcr_data);
554 
555 	if (sc->sc_intr_number != -1 && sc->sc_intr_pipe == NULL) {
556 		sc->sc_status = 0; /* clear status bit */
557 		sc->sc_intr_buf = kmem_alloc(sc->sc_isize, KM_SLEEP);
558 		err = usbd_open_pipe_intr(sc->sc_iface, sc->sc_intr_number,
559 			USBD_SHORT_XFER_OK, &sc->sc_intr_pipe, sc,
560 			sc->sc_intr_buf, sc->sc_isize,
561 			umct_intr, USBD_DEFAULT_INTERVAL);
562 		if (err) {
563 			DPRINTF(("%s: cannot open interrupt pipe (addr %d)\n",
564 				device_xname(sc->sc_dev), sc->sc_intr_number));
565 			return EIO;
566 		}
567 	}
568 
569 	return 0;
570 }
571 
572 void
573 umct_close(void *addr, int portno)
574 {
575 	struct umct_softc *sc = addr;
576 
577 	DPRINTF(("umct_close: close\n"));
578 
579 	if (sc->sc_dying)
580 		return;
581 	umct_close_pipe(sc);
582 }
583 
584 void
585 umct_intr(struct usbd_xfer *xfer, void *priv,
586     usbd_status status)
587 {
588 	struct umct_softc *sc = priv;
589 	u_char *tbuf = sc->sc_intr_buf;
590 	u_char mstatus;
591 
592 	if (sc->sc_dying)
593 		return;
594 
595 	if (status != USBD_NORMAL_COMPLETION) {
596 		if (status == USBD_NOT_STARTED || status == USBD_CANCELLED)
597 			return;
598 
599 		DPRINTF(("%s: abnormal status: %s\n", device_xname(sc->sc_dev),
600 			usbd_errstr(status)));
601 		usbd_clear_endpoint_stall_async(sc->sc_intr_pipe);
602 		return;
603 	}
604 
605 	DPRINTF(("%s: umct status = MSR:%02x, LSR:%02x\n",
606 		 device_xname(sc->sc_dev), tbuf[0],tbuf[1]));
607 
608 	sc->sc_lsr = sc->sc_msr = 0;
609 	mstatus = tbuf[0];
610 	if (ISSET(mstatus, MSR_DSR))
611 		sc->sc_msr |= UMSR_DSR;
612 	if (ISSET(mstatus, MSR_DCD))
613 		sc->sc_msr |= UMSR_DCD;
614 	ucom_status_change(device_private(sc->sc_subdev));
615 }
616 
617 void
618 umct_get_status(void *addr, int portno, u_char *lsr, u_char *msr)
619 {
620 	struct umct_softc *sc = addr;
621 
622 	DPRINTF(("umct_get_status:\n"));
623 
624 	if (sc->sc_dying)
625 		return;
626 
627 	*lsr = sc->sc_lsr;
628 	*msr = sc->sc_msr;
629 }
630