xref: /netbsd-src/sys/dev/usb/ucom.c (revision 627f7eb200a4419d89b531d55fccd2ee3ffdcde0)
1 /*	$NetBSD: ucom.c,v 1.128 2020/10/26 12:24:10 mrg Exp $	*/
2 
3 /*
4  * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Lennart Augustsson (lennart@augustsson.net) at
9  * Carlstedt Research & Technology.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 /*
33  * This code is very heavily based on the 16550 driver, com.c.
34  */
35 
36 #include <sys/cdefs.h>
37 __KERNEL_RCSID(0, "$NetBSD: ucom.c,v 1.128 2020/10/26 12:24:10 mrg Exp $");
38 
39 #ifdef _KERNEL_OPT
40 #include "opt_usb.h"
41 #endif
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
46 #include <sys/ioctl.h>
47 #include <sys/conf.h>
48 #include <sys/tty.h>
49 #include <sys/file.h>
50 #include <sys/select.h>
51 #include <sys/proc.h>
52 #include <sys/vnode.h>
53 #include <sys/device.h>
54 #include <sys/poll.h>
55 #include <sys/queue.h>
56 #include <sys/kauth.h>
57 #include <sys/sysctl.h>
58 #include <sys/timepps.h>
59 #include <sys/rndsource.h>
60 
61 #include <dev/usb/usb.h>
62 
63 #include <dev/usb/usbdi.h>
64 #include <dev/usb/usbdi_util.h>
65 #include <dev/usb/usbdevs.h>
66 #include <dev/usb/usb_quirks.h>
67 #include <dev/usb/usbhist.h>
68 
69 #include <dev/usb/ucomvar.h>
70 
71 #include "ucom.h"
72 #include "locators.h"
73 #include "ioconf.h"
74 
75 #if NUCOM > 0
76 
77 #ifdef USB_DEBUG
78 #ifndef UCOM_DEBUG
79 #define ucomdebug 0
80 #else
81 int ucomdebug = 0;
82 
83 SYSCTL_SETUP(sysctl_hw_ucom_setup, "sysctl hw.ucom setup")
84 {
85 	int err;
86 	const struct sysctlnode *rnode;
87 	const struct sysctlnode *cnode;
88 
89 	err = sysctl_createv(clog, 0, NULL, &rnode,
90 	    CTLFLAG_PERMANENT, CTLTYPE_NODE, "ucom",
91 	    SYSCTL_DESCR("ucom global controls"),
92 	    NULL, 0, NULL, 0, CTL_HW, CTL_CREATE, CTL_EOL);
93 
94 	if (err)
95 		goto fail;
96 
97 	/* control debugging printfs */
98 	err = sysctl_createv(clog, 0, &rnode, &cnode,
99 	    CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT,
100 	    "debug", SYSCTL_DESCR("Enable debugging output"),
101 	    NULL, 0, &ucomdebug, sizeof(ucomdebug), CTL_CREATE, CTL_EOL);
102 	if (err)
103 		goto fail;
104 
105 	return;
106 fail:
107 	aprint_error("%s: sysctl_createv failed (err = %d)\n", __func__, err);
108 }
109 
110 #endif /* UCOM_DEBUG */
111 #endif /* USB_DEBUG */
112 
113 #define DPRINTF(FMT,A,B,C,D)    USBHIST_LOGN(ucomdebug,1,FMT,A,B,C,D)
114 #define DPRINTFN(N,FMT,A,B,C,D) USBHIST_LOGN(ucomdebug,N,FMT,A,B,C,D)
115 #define UCOMHIST_FUNC()         USBHIST_FUNC()
116 #define UCOMHIST_CALLED(name)   USBHIST_CALLED(ucomdebug)
117 
118 #define	UCOMCALLUNIT_MASK	TTCALLUNIT_MASK
119 #define	UCOMUNIT_MASK		TTUNIT_MASK
120 #define	UCOMDIALOUT_MASK	TTDIALOUT_MASK
121 
122 #define	UCOMCALLUNIT(x)		TTCALLUNIT(x)
123 #define	UCOMUNIT(x)		TTUNIT(x)
124 #define	UCOMDIALOUT(x)		TTDIALOUT(x)
125 
126 /*
127  * XXX: We can submit multiple input/output buffers to the usb stack
128  * to improve throughput, but the usb stack is too lame to deal with this
129  * in a number of places.
130  */
131 #define	UCOM_IN_BUFFS	1
132 #define	UCOM_OUT_BUFFS	1
133 
134 struct ucom_buffer {
135 	SIMPLEQ_ENTRY(ucom_buffer) ub_link;
136 	struct usbd_xfer *ub_xfer;
137 	u_char *ub_data;
138 	u_int ub_len;
139 	u_int ub_index;
140 };
141 
142 struct ucom_softc {
143 	device_t		sc_dev;		/* base device */
144 
145 	struct usbd_device *	sc_udev;	/* USB device */
146 	struct usbd_interface *	sc_iface;	/* data interface */
147 
148 	int			sc_bulkin_no;	/* bulk in endpoint address */
149 	struct usbd_pipe *	sc_bulkin_pipe;/* bulk in pipe */
150 	u_int			sc_ibufsize;	/* read buffer size */
151 	u_int			sc_ibufsizepad;	/* read buffer size padded */
152 	struct ucom_buffer	sc_ibuff[UCOM_IN_BUFFS];
153 	SIMPLEQ_HEAD(, ucom_buffer) sc_ibuff_empty;
154 	SIMPLEQ_HEAD(, ucom_buffer) sc_ibuff_full;
155 
156 	int			sc_bulkout_no;	/* bulk out endpoint address */
157 	struct usbd_pipe *	sc_bulkout_pipe;/* bulk out pipe */
158 	u_int			sc_obufsize;	/* write buffer size */
159 	u_int			sc_opkthdrlen;	/* header length of */
160 	struct ucom_buffer	sc_obuff[UCOM_OUT_BUFFS];
161 	SIMPLEQ_HEAD(, ucom_buffer) sc_obuff_free;
162 	SIMPLEQ_HEAD(, ucom_buffer) sc_obuff_full;
163 
164 	void			*sc_si;
165 
166 	const struct ucom_methods *sc_methods;
167 	void                    *sc_parent;
168 	int			sc_portno;
169 
170 	struct tty		*sc_tty;	/* our tty */
171 	u_char			sc_lsr;
172 	u_char			sc_msr;
173 	u_char			sc_mcr;
174 	volatile u_char		sc_rx_stopped;
175 	u_char			sc_rx_unblock;
176 	u_char			sc_tx_stopped;
177 	int			sc_swflags;
178 
179 	enum ucom_state {
180 	    UCOM_DEAD,
181 	    UCOM_ATTACHED,
182 	    UCOM_OPENING,
183 	    UCOM_CLOSING,
184 	    UCOM_OPEN
185 	}			sc_state;
186 	int			sc_refcnt;
187 	bool			sc_dying;	/* disconnecting */
188 
189 	struct pps_state	sc_pps_state;	/* pps state */
190 
191 	krndsource_t		sc_rndsource;	/* random source */
192 
193 	kmutex_t		sc_lock;
194 	kcondvar_t		sc_statecv;
195 	kcondvar_t		sc_detachcv;
196 };
197 
198 dev_type_open(ucomopen);
199 dev_type_close(ucomclose);
200 dev_type_read(ucomread);
201 dev_type_write(ucomwrite);
202 dev_type_ioctl(ucomioctl);
203 dev_type_stop(ucomstop);
204 dev_type_tty(ucomtty);
205 dev_type_poll(ucompoll);
206 
207 const struct cdevsw ucom_cdevsw = {
208 	.d_open = ucomopen,
209 	.d_close = ucomclose,
210 	.d_read = ucomread,
211 	.d_write = ucomwrite,
212 	.d_ioctl = ucomioctl,
213 	.d_stop = ucomstop,
214 	.d_tty = ucomtty,
215 	.d_poll = ucompoll,
216 	.d_mmap = nommap,
217 	.d_kqfilter = ttykqfilter,
218 	.d_discard = nodiscard,
219 	.d_flag = D_TTY | D_MPSAFE
220 };
221 
222 static void	ucom_cleanup(struct ucom_softc *);
223 static int	ucomparam(struct tty *, struct termios *);
224 static int	ucomhwiflow(struct tty *, int);
225 static void	ucomstart(struct tty *);
226 static void	ucom_shutdown(struct ucom_softc *);
227 static int	ucom_do_ioctl(struct ucom_softc *, u_long, void *,
228 			      int, struct lwp *);
229 static void	ucom_dtr(struct ucom_softc *, int);
230 static void	ucom_rts(struct ucom_softc *, int);
231 static void	ucom_break(struct ucom_softc *, int);
232 static void	tiocm_to_ucom(struct ucom_softc *, u_long, int);
233 static int	ucom_to_tiocm(struct ucom_softc *);
234 
235 static void	ucomreadcb(struct usbd_xfer *, void *, usbd_status);
236 static void	ucom_submit_write(struct ucom_softc *, struct ucom_buffer *);
237 static void	ucom_write_status(struct ucom_softc *, struct ucom_buffer *,
238 		    usbd_status);
239 
240 static void	ucomwritecb(struct usbd_xfer *, void *, usbd_status);
241 static void	ucom_read_complete(struct ucom_softc *);
242 static int	ucomsubmitread(struct ucom_softc *, struct ucom_buffer *);
243 static void	ucom_softintr(void *);
244 
245 int ucom_match(device_t, cfdata_t, void *);
246 void ucom_attach(device_t, device_t, void *);
247 int ucom_detach(device_t, int);
248 
249 CFATTACH_DECL_NEW(ucom, sizeof(struct ucom_softc), ucom_match, ucom_attach,
250     ucom_detach, NULL);
251 
252 int
253 ucom_match(device_t parent, cfdata_t match, void *aux)
254 {
255 	return 1;
256 }
257 
258 void
259 ucom_attach(device_t parent, device_t self, void *aux)
260 {
261 	struct ucom_softc *sc = device_private(self);
262 	struct ucom_attach_args *ucaa = aux;
263 
264 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
265 
266 	if (ucaa->ucaa_info != NULL)
267 		aprint_normal(": %s", ucaa->ucaa_info);
268 	aprint_normal("\n");
269 
270 	prop_dictionary_set_int32(device_properties(self), "port",
271 	    ucaa->ucaa_portno);
272 
273 	sc->sc_dev = self;
274 	sc->sc_udev = ucaa->ucaa_device;
275 	sc->sc_iface = ucaa->ucaa_iface;
276 	sc->sc_bulkout_no = ucaa->ucaa_bulkout;
277 	sc->sc_bulkin_no = ucaa->ucaa_bulkin;
278 	sc->sc_ibufsize = ucaa->ucaa_ibufsize;
279 	sc->sc_ibufsizepad = ucaa->ucaa_ibufsizepad;
280 	sc->sc_obufsize = ucaa->ucaa_obufsize;
281 	sc->sc_opkthdrlen = ucaa->ucaa_opkthdrlen;
282 	sc->sc_methods = ucaa->ucaa_methods;
283 	sc->sc_parent = ucaa->ucaa_arg;
284 	sc->sc_portno = ucaa->ucaa_portno;
285 
286 	sc->sc_lsr = 0;
287 	sc->sc_msr = 0;
288 	sc->sc_mcr = 0;
289 	sc->sc_tx_stopped = 0;
290 	sc->sc_swflags = 0;
291 	sc->sc_refcnt = 0;
292 	sc->sc_dying = false;
293 	sc->sc_state = UCOM_DEAD;
294 
295 	sc->sc_si = softint_establish(SOFTINT_USB, ucom_softintr, sc);
296 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_SOFTUSB);
297 	cv_init(&sc->sc_statecv, "ucomstate");
298 	cv_init(&sc->sc_detachcv, "ucomdtch");
299 
300 	SIMPLEQ_INIT(&sc->sc_ibuff_empty);
301 	SIMPLEQ_INIT(&sc->sc_ibuff_full);
302 	SIMPLEQ_INIT(&sc->sc_obuff_free);
303 	SIMPLEQ_INIT(&sc->sc_obuff_full);
304 
305 	memset(sc->sc_ibuff, 0, sizeof(sc->sc_ibuff));
306 	memset(sc->sc_obuff, 0, sizeof(sc->sc_obuff));
307 
308 	DPRINTF("open pipes in=%jd out=%jd",
309 	    sc->sc_bulkin_no, sc->sc_bulkout_no, 0, 0);
310 
311 	struct ucom_buffer *ub;
312 	usbd_status err;
313 	int error;
314 
315 	/* Open the bulk pipes */
316 	err = usbd_open_pipe(sc->sc_iface, sc->sc_bulkin_no,
317 	    USBD_EXCLUSIVE_USE, &sc->sc_bulkin_pipe);
318 	if (err) {
319 		DPRINTF("open bulk in error (addr %jd), err=%jd",
320 		    sc->sc_bulkin_no, err, 0, 0);
321 		error = EIO;
322 		goto fail_0;
323 	}
324 	/* Allocate input buffers */
325 	for (ub = &sc->sc_ibuff[0]; ub != &sc->sc_ibuff[UCOM_IN_BUFFS];
326 	    ub++) {
327 		error = usbd_create_xfer(sc->sc_bulkin_pipe,
328 		    sc->sc_ibufsizepad, 0, 0,
329 		    &ub->ub_xfer);
330 		if (error)
331 			goto fail_1;
332 		ub->ub_data = usbd_get_buffer(ub->ub_xfer);
333 	}
334 
335 	err = usbd_open_pipe(sc->sc_iface, sc->sc_bulkout_no,
336 	    USBD_EXCLUSIVE_USE, &sc->sc_bulkout_pipe);
337 	if (err) {
338 		DPRINTF("open bulk out error (addr %jd), err=%jd",
339 		    sc->sc_bulkout_no, err, 0, 0);
340 		error = EIO;
341 		goto fail_1;
342 	}
343 	for (ub = &sc->sc_obuff[0]; ub != &sc->sc_obuff[UCOM_OUT_BUFFS];
344 	    ub++) {
345 		error = usbd_create_xfer(sc->sc_bulkout_pipe,
346 		    sc->sc_obufsize, 0, 0, &ub->ub_xfer);
347 		if (error)
348 			goto fail_2;
349 		ub->ub_data = usbd_get_buffer(ub->ub_xfer);
350 		SIMPLEQ_INSERT_TAIL(&sc->sc_obuff_free, ub, ub_link);
351 	}
352 
353 	struct tty *tp = tty_alloc();
354 	tp->t_oproc = ucomstart;
355 	tp->t_param = ucomparam;
356 	tp->t_hwiflow = ucomhwiflow;
357 	sc->sc_tty = tp;
358 
359 	DPRINTF("tty_attach %#jx", (uintptr_t)tp, 0, 0, 0);
360 	tty_attach(tp);
361 
362 	rnd_attach_source(&sc->sc_rndsource, device_xname(sc->sc_dev),
363 			  RND_TYPE_TTY, RND_FLAG_DEFAULT);
364 
365 	if (!pmf_device_register(self, NULL, NULL))
366 		aprint_error_dev(self, "couldn't establish power handler\n");
367 
368 	sc->sc_state = UCOM_ATTACHED;
369 
370 	return;
371 
372 fail_2:
373 	for (ub = &sc->sc_obuff[0]; ub != &sc->sc_obuff[UCOM_OUT_BUFFS];
374 	    ub++) {
375 		if (ub->ub_xfer)
376 			usbd_destroy_xfer(ub->ub_xfer);
377 	}
378 
379 	usbd_close_pipe(sc->sc_bulkout_pipe);
380 
381 fail_1:
382 	for (ub = &sc->sc_ibuff[0]; ub != &sc->sc_ibuff[UCOM_IN_BUFFS];
383 	    ub++) {
384 		if (ub->ub_xfer)
385 			usbd_destroy_xfer(ub->ub_xfer);
386 	}
387 	usbd_close_pipe(sc->sc_bulkin_pipe);
388 
389 fail_0:
390 	aprint_error_dev(self, "attach failed, error=%d\n", error);
391 
392 	return;
393 }
394 
395 int
396 ucom_detach(device_t self, int flags)
397 {
398 	struct ucom_softc *sc = device_private(self);
399 	struct tty *tp = sc->sc_tty;
400 	int maj, mn;
401 	int i;
402 
403 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
404 
405 	DPRINTF("sc=%#jx flags=%jd tp=%#jx", (uintptr_t)sc, flags,
406 	    (uintptr_t)tp, 0);
407 	DPRINTF("... pipe=%jd,%jd", sc->sc_bulkin_no, sc->sc_bulkout_no, 0, 0);
408 
409 	mutex_enter(&sc->sc_lock);
410 	sc->sc_dying = true;
411 	mutex_exit(&sc->sc_lock);
412 
413 	pmf_device_deregister(self);
414 
415 	if (sc->sc_bulkin_pipe != NULL) {
416 		usbd_abort_pipe(sc->sc_bulkin_pipe);
417 		sc->sc_bulkin_pipe = NULL;
418 	}
419 	if (sc->sc_bulkout_pipe != NULL) {
420 		usbd_abort_pipe(sc->sc_bulkout_pipe);
421 		sc->sc_bulkout_pipe = NULL;
422 	}
423 
424 	mutex_enter(&sc->sc_lock);
425 
426 	/* wait for open/close to finish */
427 	while (sc->sc_state == UCOM_OPENING || sc->sc_state == UCOM_CLOSING) {
428 		int error = cv_wait_sig(&sc->sc_statecv, &sc->sc_lock);
429 
430 		if (error) {
431 			mutex_exit(&sc->sc_lock);
432 			return error;
433 		}
434 	}
435 
436 	sc->sc_refcnt--;
437 	while (sc->sc_refcnt >= 0) {
438 		/* Wake up anyone waiting */
439 		if (tp != NULL) {
440 			mutex_spin_enter(&tty_lock);
441 			CLR(tp->t_state, TS_CARR_ON);
442 			CLR(tp->t_cflag, CLOCAL | MDMBUF);
443 			ttyflush(tp, FREAD|FWRITE);
444 			mutex_spin_exit(&tty_lock);
445 		}
446 		/* Wait for processes to go away. */
447 		if (cv_timedwait(&sc->sc_detachcv, &sc->sc_lock, hz * 60))
448 			aprint_error_dev(self, ": didn't detach\n");
449 	}
450 
451 	softint_disestablish(sc->sc_si);
452 	mutex_exit(&sc->sc_lock);
453 
454 	/* locate the major number */
455 	maj = cdevsw_lookup_major(&ucom_cdevsw);
456 
457 	/* Nuke the vnodes for any open instances. */
458 	mn = device_unit(self);
459 	DPRINTF("maj=%jd mn=%jd", maj, mn, 0, 0);
460 	vdevgone(maj, mn, mn, VCHR);
461 	vdevgone(maj, mn | UCOMDIALOUT_MASK, mn | UCOMDIALOUT_MASK, VCHR);
462 	vdevgone(maj, mn | UCOMCALLUNIT_MASK, mn | UCOMCALLUNIT_MASK, VCHR);
463 
464 	/* Detach and free the tty. */
465 	if (tp != NULL) {
466 		tty_detach(tp);
467 		tty_free(tp);
468 		sc->sc_tty = NULL;
469 	}
470 
471 	for (i = 0; i < UCOM_IN_BUFFS; i++) {
472 		if (sc->sc_ibuff[i].ub_xfer != NULL)
473 			usbd_destroy_xfer(sc->sc_ibuff[i].ub_xfer);
474 	}
475 
476 	for (i = 0; i < UCOM_OUT_BUFFS; i++) {
477 		if (sc->sc_obuff[i].ub_xfer != NULL)
478 			usbd_destroy_xfer(sc->sc_obuff[i].ub_xfer);
479 	}
480 
481 	if (sc->sc_bulkin_pipe != NULL) {
482 		usbd_close_pipe(sc->sc_bulkin_pipe);
483 		sc->sc_bulkin_pipe = NULL;
484 	}
485 
486 	if (sc->sc_bulkout_pipe != NULL) {
487 		usbd_close_pipe(sc->sc_bulkout_pipe);
488 		sc->sc_bulkout_pipe = NULL;
489 	}
490 
491 	/* Detach the random source */
492 	rnd_detach_source(&sc->sc_rndsource);
493 
494 	mutex_destroy(&sc->sc_lock);
495 	cv_destroy(&sc->sc_statecv);
496 	cv_destroy(&sc->sc_detachcv);
497 
498 	return 0;
499 }
500 
501 void
502 ucom_shutdown(struct ucom_softc *sc)
503 {
504 	struct tty *tp = sc->sc_tty;
505 
506 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
507 
508 	/*
509 	 * Hang up if necessary.  Wait a bit, so the other side has time to
510 	 * notice even if we immediately open the port again.
511 	 */
512 	if (ISSET(tp->t_cflag, HUPCL)) {
513 		ucom_dtr(sc, 0);
514 		/* XXX will only timeout */
515 		(void) kpause(ttclos, false, hz, NULL);
516 	}
517 }
518 
519 int
520 ucomopen(dev_t dev, int flag, int mode, struct lwp *l)
521 {
522 	const int unit = UCOMUNIT(dev);
523 	struct ucom_softc * const sc = device_lookup_private(&ucom_cd, unit);
524 	int error = 0;
525 
526 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
527 
528 	if (sc == NULL)
529 		return ENXIO;
530 
531 	mutex_enter(&sc->sc_lock);
532 	if (sc->sc_dying) {
533 		DPRINTF("... dying", 0, 0, 0, 0);
534 		mutex_exit(&sc->sc_lock);
535 		return EIO;
536 	}
537 
538 	if (!device_is_active(sc->sc_dev)) {
539 		mutex_exit(&sc->sc_lock);
540 		return ENXIO;
541 	}
542 
543 	struct tty *tp = sc->sc_tty;
544 
545 	DPRINTF("unit=%jd, tp=%#jx", unit, (uintptr_t)tp, 0, 0);
546 
547 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp)) {
548 		mutex_exit(&sc->sc_lock);
549 		return EBUSY;
550 	}
551 
552 	/*
553 	 * Wait while the device is initialized by the
554 	 * first opener or cleaned up by the last closer.
555 	 */
556 	while (sc->sc_state == UCOM_OPENING || sc->sc_state == UCOM_CLOSING) {
557 		error = cv_wait_sig(&sc->sc_statecv, &sc->sc_lock);
558 
559 		if (sc->sc_dying)
560 			error = EIO;
561 
562 		if (error) {
563 			mutex_exit(&sc->sc_lock);
564 			return error;
565 		}
566 	}
567 	enum ucom_state state = sc->sc_state;
568 
569 	KASSERTMSG(state == UCOM_OPEN || state == UCOM_ATTACHED,
570 	    "state is %d", state);
571 
572 	bool cleanup = false;
573 	/* If this is the first open then perform the initialisation */
574 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
575 		KASSERT(state == UCOM_ATTACHED);
576 		tp->t_dev = dev;
577 		cleanup = true;
578 		sc->sc_state = UCOM_OPENING;
579 
580 		mutex_exit(&sc->sc_lock);
581 		if (sc->sc_methods->ucom_open != NULL) {
582 			error = sc->sc_methods->ucom_open(sc->sc_parent,
583 			    sc->sc_portno);
584 			if (error) {
585 				goto fail_2;
586 			}
587 		}
588 
589 		ucom_status_change(sc);
590 
591 		/* Clear PPS capture state on first open. */
592 		mutex_spin_enter(&timecounter_lock);
593 		memset(&sc->sc_pps_state, 0, sizeof(sc->sc_pps_state));
594 		sc->sc_pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
595 		pps_init(&sc->sc_pps_state);
596 		mutex_spin_exit(&timecounter_lock);
597 
598 		/*
599 		 * Initialize the termios status to the defaults.  Add in the
600 		 * sticky bits from TIOCSFLAGS.
601 		 */
602 		struct termios t;
603 
604 		t.c_ispeed = 0;
605 		t.c_ospeed = TTYDEF_SPEED;
606 		t.c_cflag = TTYDEF_CFLAG;
607 		if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
608 			SET(t.c_cflag, CLOCAL);
609 		if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
610 			SET(t.c_cflag, CRTSCTS);
611 		if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
612 			SET(t.c_cflag, MDMBUF);
613 		/* Make sure ucomparam() will do something. */
614 		tp->t_ospeed = 0;
615 		(void) ucomparam(tp, &t);
616 		tp->t_iflag = TTYDEF_IFLAG;
617 		tp->t_oflag = TTYDEF_OFLAG;
618 		tp->t_lflag = TTYDEF_LFLAG;
619 		ttychars(tp);
620 		ttsetwater(tp);
621 
622 		/*
623 		 * Turn on DTR.  We must always do this, even if carrier is not
624 		 * present, because otherwise we'd have to use TIOCSDTR
625 		 * immediately after setting CLOCAL, which applications do not
626 		 * expect.  We always assert DTR while the device is open
627 		 * unless explicitly requested to deassert it.  Ditto RTS.
628 		 */
629 		ucom_dtr(sc, 1);
630 		ucom_rts(sc, 1);
631 
632 		mutex_enter(&sc->sc_lock);
633 		if (sc->sc_dying) {
634 			DPRINTF("... dying", 0, 0, 0, 0);
635 			error = EIO;
636 			goto fail_1;
637 		}
638 
639 		sc->sc_rx_unblock = 0;
640 		sc->sc_rx_stopped = 0;
641 		sc->sc_tx_stopped = 0;
642 
643 		for (size_t i = 0; i < UCOM_IN_BUFFS; i++) {
644 			struct ucom_buffer *ub = &sc->sc_ibuff[i];
645 			error = ucomsubmitread(sc, ub);
646 			if (error) {
647 		    		mutex_exit(&sc->sc_lock);
648 				goto fail_2;
649 			}
650 		}
651 	}
652 	sc->sc_state = UCOM_OPEN;
653 	cv_signal(&sc->sc_statecv);
654 	mutex_exit(&sc->sc_lock);
655 
656 	DPRINTF("unit=%jd, tp=%#jx dialout %jd nonblock %jd", unit,
657 	    (uintptr_t)tp, !!UCOMDIALOUT(dev), !!ISSET(flag, O_NONBLOCK));
658 	error = ttyopen(tp, UCOMDIALOUT(dev), ISSET(flag, O_NONBLOCK));
659 	if (error)
660 		goto bad;
661 
662 	error = (*tp->t_linesw->l_open)(dev, tp);
663 	if (error)
664 		goto bad;
665 
666 	return 0;
667 
668 bad:
669 	cleanup = !ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0;
670 
671 fail_2:
672 	if (cleanup) {
673 		/*
674 		 * We failed to open the device, and nobody else had
675 		 * it opened.  Clean up the state as appropriate.
676 		 */
677 		ucom_cleanup(sc);
678 	}
679 
680 	mutex_enter(&sc->sc_lock);
681 
682 fail_1:
683 	sc->sc_state = state;
684 	cv_signal(&sc->sc_statecv);
685 	mutex_exit(&sc->sc_lock);
686 
687 	return error;
688 }
689 
690 int
691 ucomclose(dev_t dev, int flag, int mode, struct lwp *l)
692 {
693 	const int unit = UCOMUNIT(dev);
694 	struct ucom_softc *sc = device_lookup_private(&ucom_cd, unit);
695 	int error = 0;
696 
697 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
698 
699 	DPRINTF("unit=%jd", UCOMUNIT(dev), 0, 0, 0);
700 
701 	if (sc == NULL)
702 		return 0;
703 
704 	mutex_enter(&sc->sc_lock);
705 	if (sc->sc_dying) {
706 		DPRINTF("... dying", 0, 0, 0, 0);
707 		mutex_exit(&sc->sc_lock);
708 		return ENXIO;
709 	}
710 
711 	/*
712 	 * Wait until any opens/closes have finished
713 	 */
714 	while (sc->sc_state == UCOM_OPENING || sc->sc_state == UCOM_CLOSING) {
715 		error = cv_wait_sig(&sc->sc_statecv, &sc->sc_lock);
716 
717 		if (sc->sc_dying)
718 			error = EIO;
719 
720 		if (error) {
721 			mutex_exit(&sc->sc_lock);
722 			return error;
723 		}
724 	}
725 
726 	struct tty *tp = sc->sc_tty;
727 
728 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
729 		KASSERT(sc->sc_state == UCOM_ATTACHED);
730 		mutex_exit(&sc->sc_lock);
731 		return 0;
732 	}
733 
734 	KASSERT(sc->sc_state == UCOM_OPEN);
735 	sc->sc_state = UCOM_CLOSING;
736 	mutex_exit(&sc->sc_lock);
737 
738 	(*tp->t_linesw->l_close)(tp, flag);
739 	ttyclose(tp);
740 
741 	/* state when we're done - default to open */
742 	enum ucom_state state = UCOM_OPEN;
743 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
744 		/*
745 		 * Although we got a last close, the device may still be in
746 		 * use; e.g. if this was the dialout node, and there are still
747 		 * processes waiting for carrier on the non-dialout node.
748 		 */
749 		ucom_cleanup(sc);
750 		if (sc->sc_methods->ucom_close != NULL)
751 			sc->sc_methods->ucom_close(sc->sc_parent,
752 			    sc->sc_portno);
753 		state = UCOM_ATTACHED;
754 	}
755 
756 	mutex_enter(&sc->sc_lock);
757 	sc->sc_state = state;
758 	cv_signal(&sc->sc_statecv);
759 	mutex_exit(&sc->sc_lock);
760 
761 	return error;
762 }
763 
764 int
765 ucomread(dev_t dev, struct uio *uio, int flag)
766 {
767 	const int unit = UCOMUNIT(dev);
768 	struct ucom_softc * const sc = device_lookup_private(&ucom_cd, unit);
769 	int error;
770 
771 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
772 
773 	if (sc == NULL)
774 		return EIO;
775 
776 	mutex_enter(&sc->sc_lock);
777 	if (sc->sc_dying) {
778 		DPRINTF("... dying", 0, 0, 0, 0);
779 		mutex_exit(&sc->sc_lock);
780 		return EIO;
781 	}
782 
783 	struct tty *tp = sc->sc_tty;
784 
785 	sc->sc_refcnt++;
786 	mutex_exit(&sc->sc_lock);
787 
788 	error = ((*tp->t_linesw->l_read)(tp, uio, flag));
789 
790 	mutex_enter(&sc->sc_lock);
791 	if (--sc->sc_refcnt < 0)
792 		cv_broadcast(&sc->sc_detachcv);
793 	DPRINTF("unit=%jd refcnt %jd", UCOMUNIT(dev), sc->sc_refcnt, 0, 0);
794 	mutex_exit(&sc->sc_lock);
795 
796 	return error;
797 }
798 
799 int
800 ucomwrite(dev_t dev, struct uio *uio, int flag)
801 {
802 	const int unit = UCOMUNIT(dev);
803 	struct ucom_softc * const sc = device_lookup_private(&ucom_cd, unit);
804 	int error;
805 
806 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
807 
808 	if (sc == NULL)
809 		return EIO;
810 
811 	mutex_enter(&sc->sc_lock);
812 	if (sc->sc_dying) {
813 		DPRINTF("... dying", 0, 0, 0, 0);
814 		mutex_exit(&sc->sc_lock);
815 		return EIO;
816 	}
817 
818 	struct tty *tp = sc->sc_tty;
819 
820 	sc->sc_refcnt++;
821 	mutex_exit(&sc->sc_lock);
822 
823 	error = ((*tp->t_linesw->l_write)(tp, uio, flag));
824 
825 	mutex_enter(&sc->sc_lock);
826 	if (--sc->sc_refcnt < 0)
827 		cv_broadcast(&sc->sc_detachcv);
828 	DPRINTF("unit=%jd refcnt %jd", UCOMUNIT(dev), sc->sc_refcnt, 0, 0);
829 	mutex_exit(&sc->sc_lock);
830 
831 	return error;
832 }
833 
834 int
835 ucompoll(dev_t dev, int events, struct lwp *l)
836 {
837 	const int unit = UCOMUNIT(dev);
838 	struct ucom_softc * const sc = device_lookup_private(&ucom_cd, unit);
839 
840 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
841 
842 	if (sc == NULL)
843 		return POLLHUP;
844 
845 	mutex_enter(&sc->sc_lock);
846 	if (sc->sc_dying) {
847 		DPRINTF("... dying", 0, 0, 0, 0);
848 		mutex_exit(&sc->sc_lock);
849 		return POLLHUP;
850 	}
851 	struct tty *tp = sc->sc_tty;
852 
853 	sc->sc_refcnt++;
854 	mutex_exit(&sc->sc_lock);
855 
856 	int revents = ((*tp->t_linesw->l_poll)(tp, events, l));
857 
858 	mutex_enter(&sc->sc_lock);
859 	if (--sc->sc_refcnt < 0)
860 		cv_broadcast(&sc->sc_detachcv);
861 	DPRINTF("unit=%jd refcnt %jd", UCOMUNIT(dev), sc->sc_refcnt, 0, 0);
862 	mutex_exit(&sc->sc_lock);
863 
864 	return revents;
865 }
866 
867 struct tty *
868 ucomtty(dev_t dev)
869 {
870 	const int unit = UCOMUNIT(dev);
871 	struct ucom_softc * const sc = device_lookup_private(&ucom_cd, unit);
872 
873 	return sc != NULL ? sc->sc_tty : NULL;
874 }
875 
876 int
877 ucomioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
878 {
879 	const int unit = UCOMUNIT(dev);
880 	struct ucom_softc * const sc = device_lookup_private(&ucom_cd, unit);
881 	int error;
882 
883 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
884 
885 	if (sc == NULL)
886 		return EIO;
887 
888 	mutex_enter(&sc->sc_lock);
889 	if (sc->sc_dying) {
890 		DPRINTF("... dying", 0, 0, 0, 0);
891 		mutex_exit(&sc->sc_lock);
892 		return EIO;
893 	}
894 
895 	sc->sc_refcnt++;
896 	mutex_exit(&sc->sc_lock);
897 
898 	error = ucom_do_ioctl(sc, cmd, data, flag, l);
899 
900 	mutex_enter(&sc->sc_lock);
901 	if (--sc->sc_refcnt < 0)
902 		cv_broadcast(&sc->sc_detachcv);
903 	DPRINTF("unit=%jd refcnt %jd", UCOMUNIT(dev), sc->sc_refcnt, 0, 0);
904 	mutex_exit(&sc->sc_lock);
905 
906 	return error;
907 }
908 
909 static int
910 ucom_do_ioctl(struct ucom_softc *sc, u_long cmd, void *data, int flag,
911     struct lwp *l)
912 {
913 	struct tty *tp = sc->sc_tty;
914 	int error;
915 
916 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
917 
918 	DPRINTF("cmd=0x%08jx", cmd, 0, 0, 0);
919 
920 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
921 	if (error != EPASSTHROUGH)
922 		return error;
923 
924 	error = ttioctl(tp, cmd, data, flag, l);
925 	if (error != EPASSTHROUGH)
926 		return error;
927 
928 	if (sc->sc_methods->ucom_ioctl != NULL) {
929 		error = sc->sc_methods->ucom_ioctl(sc->sc_parent,
930 		    sc->sc_portno, cmd, data, flag, l->l_proc);
931 		if (error != EPASSTHROUGH)
932 			return error;
933 	}
934 
935 	error = 0;
936 
937 	DPRINTF("our cmd=0x%08jx", cmd, 0, 0, 0);
938 
939 	switch (cmd) {
940 	case TIOCSBRK:
941 		ucom_break(sc, 1);
942 		break;
943 
944 	case TIOCCBRK:
945 		ucom_break(sc, 0);
946 		break;
947 
948 	case TIOCSDTR:
949 		ucom_dtr(sc, 1);
950 		break;
951 
952 	case TIOCCDTR:
953 		ucom_dtr(sc, 0);
954 		break;
955 
956 	case TIOCGFLAGS:
957 		mutex_enter(&sc->sc_lock);
958 		*(int *)data = sc->sc_swflags;
959 		mutex_exit(&sc->sc_lock);
960 		break;
961 
962 	case TIOCSFLAGS:
963 		error = kauth_authorize_device_tty(l->l_cred,
964 		    KAUTH_DEVICE_TTY_PRIVSET, tp);
965 		if (error)
966 			break;
967 		mutex_enter(&sc->sc_lock);
968 		sc->sc_swflags = *(int *)data;
969 		mutex_exit(&sc->sc_lock);
970 		break;
971 
972 	case TIOCMSET:
973 	case TIOCMBIS:
974 	case TIOCMBIC:
975 		tiocm_to_ucom(sc, cmd, *(int *)data);
976 		break;
977 
978 	case TIOCMGET:
979 		*(int *)data = ucom_to_tiocm(sc);
980 		break;
981 
982 	case PPS_IOC_CREATE:
983 	case PPS_IOC_DESTROY:
984 	case PPS_IOC_GETPARAMS:
985 	case PPS_IOC_SETPARAMS:
986 	case PPS_IOC_GETCAP:
987 	case PPS_IOC_FETCH:
988 #ifdef PPS_SYNC
989 	case PPS_IOC_KCBIND:
990 #endif
991 		mutex_spin_enter(&timecounter_lock);
992 		error = pps_ioctl(cmd, data, &sc->sc_pps_state);
993 		mutex_spin_exit(&timecounter_lock);
994 		break;
995 
996 	default:
997 		error = EPASSTHROUGH;
998 		break;
999 	}
1000 
1001 	return error;
1002 }
1003 
1004 static void
1005 tiocm_to_ucom(struct ucom_softc *sc, u_long how, int ttybits)
1006 {
1007 	u_char combits;
1008 
1009 	combits = 0;
1010 	if (ISSET(ttybits, TIOCM_DTR))
1011 		SET(combits, UMCR_DTR);
1012 	if (ISSET(ttybits, TIOCM_RTS))
1013 		SET(combits, UMCR_RTS);
1014 
1015 	mutex_enter(&sc->sc_lock);
1016 	switch (how) {
1017 	case TIOCMBIC:
1018 		CLR(sc->sc_mcr, combits);
1019 		break;
1020 
1021 	case TIOCMBIS:
1022 		SET(sc->sc_mcr, combits);
1023 		break;
1024 
1025 	case TIOCMSET:
1026 		CLR(sc->sc_mcr, UMCR_DTR | UMCR_RTS);
1027 		SET(sc->sc_mcr, combits);
1028 		break;
1029 	}
1030 	u_char mcr = sc->sc_mcr;
1031 	mutex_exit(&sc->sc_lock);
1032 
1033 	if (how == TIOCMSET || ISSET(combits, UMCR_DTR))
1034 		ucom_dtr(sc, (mcr & UMCR_DTR) != 0);
1035 	if (how == TIOCMSET || ISSET(combits, UMCR_RTS))
1036 		ucom_rts(sc, (mcr & UMCR_RTS) != 0);
1037 }
1038 
1039 static int
1040 ucom_to_tiocm(struct ucom_softc *sc)
1041 {
1042 	u_char combits;
1043 	int ttybits = 0;
1044 
1045 	mutex_enter(&sc->sc_lock);
1046 	combits = sc->sc_mcr;
1047 	if (ISSET(combits, UMCR_DTR))
1048 		SET(ttybits, TIOCM_DTR);
1049 	if (ISSET(combits, UMCR_RTS))
1050 		SET(ttybits, TIOCM_RTS);
1051 
1052 	combits = sc->sc_msr;
1053 	if (ISSET(combits, UMSR_DCD))
1054 		SET(ttybits, TIOCM_CD);
1055 	if (ISSET(combits, UMSR_CTS))
1056 		SET(ttybits, TIOCM_CTS);
1057 	if (ISSET(combits, UMSR_DSR))
1058 		SET(ttybits, TIOCM_DSR);
1059 	if (ISSET(combits, UMSR_RI | UMSR_TERI))
1060 		SET(ttybits, TIOCM_RI);
1061 
1062 #if 0
1063 XXX;
1064 	if (sc->sc_ier != 0)
1065 		SET(ttybits, TIOCM_LE);
1066 #endif
1067 	mutex_exit(&sc->sc_lock);
1068 
1069 	return ttybits;
1070 }
1071 
1072 static void
1073 ucom_break(struct ucom_softc *sc, int onoff)
1074 {
1075 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
1076 
1077 	DPRINTF("onoff=%jd", onoff, 0, 0, 0);
1078 
1079 	if (sc->sc_methods->ucom_set != NULL)
1080 		sc->sc_methods->ucom_set(sc->sc_parent, sc->sc_portno,
1081 		    UCOM_SET_BREAK, onoff);
1082 }
1083 
1084 static void
1085 ucom_dtr(struct ucom_softc *sc, int onoff)
1086 {
1087 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
1088 
1089 	DPRINTF("onoff=%jd", onoff, 0, 0, 0);
1090 
1091 	if (sc->sc_methods->ucom_set != NULL)
1092 		sc->sc_methods->ucom_set(sc->sc_parent, sc->sc_portno,
1093 		    UCOM_SET_DTR, onoff);
1094 }
1095 
1096 static void
1097 ucom_rts(struct ucom_softc *sc, int onoff)
1098 {
1099 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
1100 
1101 	DPRINTF("onoff=%jd", onoff, 0, 0, 0);
1102 
1103 	if (sc->sc_methods->ucom_set != NULL)
1104 		sc->sc_methods->ucom_set(sc->sc_parent, sc->sc_portno,
1105 		    UCOM_SET_RTS, onoff);
1106 }
1107 
1108 void
1109 ucom_status_change(struct ucom_softc *sc)
1110 {
1111 	struct tty *tp = sc->sc_tty;
1112 
1113 	if (sc->sc_methods->ucom_get_status != NULL) {
1114 		u_char msr, lsr;
1115 
1116 		sc->sc_methods->ucom_get_status(sc->sc_parent, sc->sc_portno,
1117 		    &lsr, &msr);
1118 		mutex_enter(&sc->sc_lock);
1119 		u_char old_msr = sc->sc_msr;
1120 
1121 		sc->sc_lsr = lsr;
1122 		sc->sc_msr = msr;
1123 		mutex_exit(&sc->sc_lock);
1124 
1125 		if (ISSET((msr ^ old_msr), UMSR_DCD)) {
1126 			mutex_spin_enter(&timecounter_lock);
1127 			pps_capture(&sc->sc_pps_state);
1128 			pps_event(&sc->sc_pps_state,
1129 			    (sc->sc_msr & UMSR_DCD) ?
1130 			    PPS_CAPTUREASSERT :
1131 			    PPS_CAPTURECLEAR);
1132 			mutex_spin_exit(&timecounter_lock);
1133 
1134 			(*tp->t_linesw->l_modem)(tp, ISSET(msr, UMSR_DCD));
1135 		}
1136 	} else {
1137 		mutex_enter(&sc->sc_lock);
1138 		sc->sc_lsr = 0;
1139 		/* Assume DCD is present, if we have no chance to check it. */
1140 		sc->sc_msr = UMSR_DCD;
1141 		mutex_exit(&sc->sc_lock);
1142 	}
1143 }
1144 
1145 static int
1146 ucomparam(struct tty *tp, struct termios *t)
1147 {
1148 	const int unit = UCOMUNIT(tp->t_dev);
1149 	struct ucom_softc * const sc = device_lookup_private(&ucom_cd, unit);
1150 	int error = 0;
1151 
1152 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
1153 
1154 	if (sc == NULL)
1155 		return EIO;
1156 
1157 	mutex_enter(&sc->sc_lock);
1158 	if (sc->sc_dying) {
1159 		DPRINTF("... dying", 0, 0, 0, 0);
1160 		mutex_exit(&sc->sc_lock);
1161 		return EIO;
1162 	}
1163 
1164 	sc->sc_refcnt++;
1165 	mutex_exit(&sc->sc_lock);
1166 
1167 	/* Check requested parameters. */
1168 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed) {
1169 		error = EINVAL;
1170 		goto out;
1171 	}
1172 
1173 	/*
1174 	 * For the console, always force CLOCAL and !HUPCL, so that the port
1175 	 * is always active.
1176 	 */
1177 	if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR)) {
1178 		SET(t->c_cflag, CLOCAL);
1179 		CLR(t->c_cflag, HUPCL);
1180 	}
1181 
1182 	/*
1183 	 * If there were no changes, don't do anything.  This avoids dropping
1184 	 * input and improves performance when all we did was frob things like
1185 	 * VMIN and VTIME.
1186 	 */
1187 	if (tp->t_ospeed == t->c_ospeed &&
1188 	    tp->t_cflag == t->c_cflag) {
1189 		goto out;
1190 	}
1191 
1192 	/* XXX lcr = ISSET(sc->sc_lcr, LCR_SBREAK) | cflag2lcr(t->c_cflag); */
1193 
1194 	/* And copy to tty. */
1195 	tp->t_ispeed = 0;
1196 	tp->t_ospeed = t->c_ospeed;
1197 	tp->t_cflag = t->c_cflag;
1198 
1199 	if (sc->sc_methods->ucom_param != NULL) {
1200 		error = sc->sc_methods->ucom_param(sc->sc_parent, sc->sc_portno,
1201 		    t);
1202 		if (error)
1203 			goto out;
1204 	}
1205 
1206 	/* XXX worry about CHWFLOW */
1207 
1208 	/*
1209 	 * Update the tty layer's idea of the carrier bit, in case we changed
1210 	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
1211 	 * explicit request.
1212 	 */
1213 	DPRINTF("l_modem", 0, 0, 0, 0);
1214 	(void) (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, UMSR_DCD));
1215 
1216 #if 0
1217 XXX what if the hardware is not open
1218 	if (!ISSET(t->c_cflag, CHWFLOW)) {
1219 		if (sc->sc_tx_stopped) {
1220 			sc->sc_tx_stopped = 0;
1221 			ucomstart(tp);
1222 		}
1223 	}
1224 #endif
1225 out:
1226 	mutex_enter(&sc->sc_lock);
1227 	if (--sc->sc_refcnt < 0)
1228 		cv_broadcast(&sc->sc_detachcv);
1229 	DPRINTF("unit=%jd refcnt %jd", UCOMUNIT(tp->t_dev), sc->sc_refcnt,
1230 	    0, 0);
1231 
1232 	mutex_exit(&sc->sc_lock);
1233 
1234 	return error;
1235 }
1236 
1237 static int
1238 ucomhwiflow(struct tty *tp, int block)
1239 {
1240 	const int unit = UCOMUNIT(tp->t_dev);
1241 	struct ucom_softc * const sc = device_lookup_private(&ucom_cd, unit);
1242 	int old;
1243 
1244 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
1245 
1246 	if (sc == NULL)
1247 		return 0;
1248 
1249 	KASSERT(&sc->sc_lock);
1250 	KASSERT(mutex_owned(&tty_lock));
1251 
1252 	old = sc->sc_rx_stopped;
1253 	sc->sc_rx_stopped = (u_char)block;
1254 
1255 	if (old && !block) {
1256 		sc->sc_rx_unblock = 1;
1257 		kpreempt_disable();
1258 		softint_schedule(sc->sc_si);
1259 		kpreempt_enable();
1260 	}
1261 
1262 	return 1;
1263 }
1264 
1265 static void
1266 ucomstart(struct tty *tp)
1267 {
1268 	const int unit = UCOMUNIT(tp->t_dev);
1269 	struct ucom_softc * const sc = device_lookup_private(&ucom_cd, unit);
1270 	struct ucom_buffer *ub;
1271 	u_char *data;
1272 	int cnt;
1273 
1274 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
1275 
1276 	if (sc == NULL)
1277 		return;
1278 
1279 	KASSERT(&sc->sc_lock);
1280 	KASSERT(mutex_owned(&tty_lock));
1281 	if (sc->sc_dying) {
1282 		DPRINTF("... dying", 0, 0, 0, 0);
1283 		return;
1284 	}
1285 
1286 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
1287 		goto out;
1288 	if (sc->sc_tx_stopped)
1289 		goto out;
1290 
1291 	if (!ttypull(tp))
1292 		goto out;
1293 
1294 	/* Grab the first contiguous region of buffer space. */
1295 	data = tp->t_outq.c_cf;
1296 	cnt = ndqb(&tp->t_outq, 0);
1297 
1298 	if (cnt == 0)
1299 		goto out;
1300 
1301 	ub = SIMPLEQ_FIRST(&sc->sc_obuff_free);
1302 	if (ub == NULL) {
1303 		SET(tp->t_state, TS_BUSY);
1304 		goto out;
1305 	}
1306 
1307 	SIMPLEQ_REMOVE_HEAD(&sc->sc_obuff_free, ub_link);
1308 
1309 	if (SIMPLEQ_FIRST(&sc->sc_obuff_free) == NULL)
1310 		SET(tp->t_state, TS_BUSY);
1311 
1312 	if (cnt > sc->sc_obufsize)
1313 		cnt = sc->sc_obufsize;
1314 
1315 	if (sc->sc_methods->ucom_write != NULL)
1316 		sc->sc_methods->ucom_write(sc->sc_parent, sc->sc_portno,
1317 		    ub->ub_data, data, &cnt);
1318 	else
1319 		memcpy(ub->ub_data, data, cnt);
1320 
1321 	ub->ub_len = cnt;
1322 	ub->ub_index = 0;
1323 
1324 	SIMPLEQ_INSERT_TAIL(&sc->sc_obuff_full, ub, ub_link);
1325 
1326 	kpreempt_disable();
1327 	softint_schedule(sc->sc_si);
1328 	kpreempt_enable();
1329 
1330  out:
1331 	DPRINTF("... done", 0, 0, 0, 0);
1332 	return;
1333 }
1334 
1335 void
1336 ucomstop(struct tty *tp, int flag)
1337 {
1338 #if 0
1339 	const int unit = UCOMUNIT(tp->t_dev);
1340 	struct ucom_softc * const sc = device_lookup_private(&ucom_cd, unit);
1341 
1342 	mutex_enter(&sc->sc_lock);
1343 	mutex_spin_enter(&tty_lock);
1344 	if (ISSET(tp->t_state, TS_BUSY)) {
1345 		/* obuff_full -> obuff_free? */
1346 		/* sc->sc_tx_stopped = 1; */
1347 		if (!ISSET(tp->t_state, TS_TTSTOP))
1348 			SET(tp->t_state, TS_FLUSH);
1349 	}
1350 	mutex_spin_exit(&tty_lock);
1351 	mutex_exit(&sc->sc_lock);
1352 #endif
1353 }
1354 
1355 static void
1356 ucom_write_status(struct ucom_softc *sc, struct ucom_buffer *ub,
1357     usbd_status err)
1358 {
1359 	struct tty *tp = sc->sc_tty;
1360 	uint32_t cc = ub->ub_len;
1361 
1362 	KASSERT(mutex_owned(&sc->sc_lock));
1363 
1364 	switch (err) {
1365 	case USBD_IN_PROGRESS:
1366 		ub->ub_index = ub->ub_len;
1367 		break;
1368 	case USBD_STALLED:
1369 		ub->ub_index = 0;
1370 		kpreempt_disable();
1371 		softint_schedule(sc->sc_si);
1372 		kpreempt_enable();
1373 		break;
1374 	case USBD_NORMAL_COMPLETION:
1375 		usbd_get_xfer_status(ub->ub_xfer, NULL, NULL, &cc, NULL);
1376 		rnd_add_uint32(&sc->sc_rndsource, cc);
1377 		/*FALLTHROUGH*/
1378 	default:
1379 		SIMPLEQ_REMOVE_HEAD(&sc->sc_obuff_full, ub_link);
1380 		SIMPLEQ_INSERT_TAIL(&sc->sc_obuff_free, ub, ub_link);
1381 		cc -= sc->sc_opkthdrlen;
1382 
1383 		mutex_spin_enter(&tty_lock);
1384 		CLR(tp->t_state, TS_BUSY);
1385 		if (ISSET(tp->t_state, TS_FLUSH))
1386 			CLR(tp->t_state, TS_FLUSH);
1387 		else
1388 			ndflush(&tp->t_outq, cc);
1389 		mutex_spin_exit(&tty_lock);
1390 
1391 		if (err != USBD_CANCELLED && err != USBD_IOERROR &&
1392 		    !sc->sc_dying) {
1393 			if ((ub = SIMPLEQ_FIRST(&sc->sc_obuff_full)) != NULL)
1394 				ucom_submit_write(sc, ub);
1395 
1396 			mutex_spin_enter(&tty_lock);
1397 			(*tp->t_linesw->l_start)(tp);
1398 			mutex_spin_exit(&tty_lock);
1399 		}
1400 		break;
1401 	}
1402 }
1403 
1404 static void
1405 ucom_submit_write(struct ucom_softc *sc, struct ucom_buffer *ub)
1406 {
1407 
1408 	KASSERT(mutex_owned(&sc->sc_lock));
1409 
1410 	usbd_setup_xfer(ub->ub_xfer, sc, ub->ub_data, ub->ub_len,
1411 	    0, USBD_NO_TIMEOUT, ucomwritecb);
1412 
1413 	ucom_write_status(sc, ub, usbd_transfer(ub->ub_xfer));
1414 }
1415 
1416 static void
1417 ucomwritecb(struct usbd_xfer *xfer, void *p, usbd_status status)
1418 {
1419 	struct ucom_softc *sc = (struct ucom_softc *)p;
1420 
1421 	mutex_enter(&sc->sc_lock);
1422 	ucom_write_status(sc, SIMPLEQ_FIRST(&sc->sc_obuff_full), status);
1423 	mutex_exit(&sc->sc_lock);
1424 
1425 }
1426 
1427 static void
1428 ucom_softintr(void *arg)
1429 {
1430 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
1431 
1432 	struct ucom_softc *sc = arg;
1433 
1434 	mutex_enter(&sc->sc_lock);
1435 	if (sc->sc_dying) {
1436 		DPRINTF("... dying", 0, 0, 0, 0);
1437 		mutex_exit(&sc->sc_lock);
1438 		return;
1439 	}
1440 
1441 	struct tty *tp = sc->sc_tty;
1442 	mutex_enter(&tty_lock);
1443 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
1444 		mutex_exit(&tty_lock);
1445 		mutex_exit(&sc->sc_lock);
1446 		return;
1447 	}
1448 	mutex_exit(&tty_lock);
1449 
1450 	struct ucom_buffer *ub = SIMPLEQ_FIRST(&sc->sc_obuff_full);
1451 
1452 	if (ub != NULL && ub->ub_index == 0)
1453 		ucom_submit_write(sc, ub);
1454 
1455 	if (sc->sc_rx_unblock)
1456 		ucom_read_complete(sc);
1457 
1458 	mutex_exit(&sc->sc_lock);
1459 }
1460 
1461 static void
1462 ucom_read_complete(struct ucom_softc *sc)
1463 {
1464 	int (*rint)(int, struct tty *);
1465 	struct ucom_buffer *ub;
1466 	struct tty *tp;
1467 
1468 	KASSERT(mutex_owned(&sc->sc_lock));
1469 
1470 	tp = sc->sc_tty;
1471 	rint = tp->t_linesw->l_rint;
1472 	ub = SIMPLEQ_FIRST(&sc->sc_ibuff_full);
1473 
1474 	while (ub != NULL && !sc->sc_rx_stopped) {
1475 
1476 		/* XXX ttyinput takes tty_lock */
1477 		while (ub->ub_index < ub->ub_len && !sc->sc_rx_stopped) {
1478 			/* Give characters to tty layer. */
1479 			if ((*rint)(ub->ub_data[ub->ub_index], tp) == -1) {
1480 				/* Overflow: drop remainder */
1481 				ub->ub_index = ub->ub_len;
1482 			} else
1483 				ub->ub_index++;
1484 		}
1485 
1486 		if (ub->ub_index == ub->ub_len) {
1487 			SIMPLEQ_REMOVE_HEAD(&sc->sc_ibuff_full, ub_link);
1488 
1489 			sc->sc_refcnt--;
1490 			/* increments sc_refcnt */
1491 			ucomsubmitread(sc, ub);
1492 
1493 			ub = SIMPLEQ_FIRST(&sc->sc_ibuff_full);
1494 		}
1495 	}
1496 
1497 	sc->sc_rx_unblock = (ub != NULL);
1498 }
1499 
1500 static int
1501 ucomsubmitread(struct ucom_softc *sc, struct ucom_buffer *ub)
1502 {
1503 	usbd_status err;
1504 
1505 	KASSERT(mutex_owned(&sc->sc_lock));
1506 
1507 	usbd_setup_xfer(ub->ub_xfer, sc, ub->ub_data, sc->sc_ibufsize,
1508 	    USBD_SHORT_XFER_OK, USBD_NO_TIMEOUT, ucomreadcb);
1509 
1510 	if ((err = usbd_transfer(ub->ub_xfer)) != USBD_IN_PROGRESS) {
1511 		/* XXX: Recover from this, please! */
1512 		printf("%s: err=%s\n", __func__, usbd_errstr(err));
1513 		return EIO;
1514 	}
1515 
1516 	sc->sc_refcnt++;
1517 
1518 	SIMPLEQ_INSERT_TAIL(&sc->sc_ibuff_empty, ub, ub_link);
1519 
1520 	return 0;
1521 }
1522 
1523 static void
1524 ucomreadcb(struct usbd_xfer *xfer, void *p, usbd_status status)
1525 {
1526 	struct ucom_softc *sc = (struct ucom_softc *)p;
1527 	struct ucom_buffer *ub;
1528 	uint32_t cc;
1529 	u_char *cp;
1530 
1531 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
1532 
1533 	mutex_enter(&sc->sc_lock);
1534 
1535 	struct tty *tp = sc->sc_tty;
1536 
1537 	if (status == USBD_CANCELLED || status == USBD_IOERROR ||
1538 	    sc->sc_dying) {
1539 
1540 		DPRINTF("... done (status %jd dying %jd)", status, sc->sc_dying,
1541 		    0, 0);
1542 
1543 		if (status == USBD_IOERROR || sc->sc_dying) {
1544 			/* Send something to wake upper layer */
1545 			(tp->t_linesw->l_rint)('\n', tp);
1546 			mutex_spin_enter(&tty_lock);	/* XXX */
1547 			ttwakeup(tp);
1548 			mutex_spin_exit(&tty_lock);	/* XXX */
1549 		}
1550 
1551 		if (--sc->sc_refcnt < 0)
1552 			cv_broadcast(&sc->sc_detachcv);
1553 		DPRINTF("unit=%jd refcnt %jd", UCOMUNIT(tp->t_dev),
1554 		    sc->sc_refcnt, 0, 0);
1555 		mutex_exit(&sc->sc_lock);
1556 
1557 		return;
1558 	}
1559 
1560 	ub = SIMPLEQ_FIRST(&sc->sc_ibuff_empty);
1561 	SIMPLEQ_REMOVE_HEAD(&sc->sc_ibuff_empty, ub_link);
1562 
1563 	if (status != USBD_NORMAL_COMPLETION) {
1564 		if (status == USBD_STALLED) {
1565 			usbd_clear_endpoint_stall_async(sc->sc_bulkin_pipe);
1566 		} else {
1567 			printf("ucomreadcb: wonky status=%s\n",
1568 			    usbd_errstr(status));
1569 		}
1570 
1571 		DPRINTF("... done (status %jd)", status, 0, 0, 0);
1572 		sc->sc_refcnt--;
1573 		/* re-adds ub to sc_ibuff_empty and increments sc_refcnt */
1574 		ucomsubmitread(sc, ub);
1575 		mutex_exit(&sc->sc_lock);
1576 		return;
1577 	}
1578 
1579 	usbd_get_xfer_status(xfer, NULL, (void *)&cp, &cc, NULL);
1580 
1581 #ifdef UCOM_DEBUG
1582 	/* This is triggered by uslsa(4) occasionally. */
1583 	if ((ucomdebug > 0) && (cc == 0)) {
1584 		device_printf(sc->sc_dev, "ucomreadcb: zero length xfer!\n");
1585 	}
1586 #endif
1587 	KDASSERT(cp == ub->ub_data);
1588 
1589 	rnd_add_uint32(&sc->sc_rndsource, cc);
1590 
1591 	if (sc->sc_state != UCOM_OPEN) {
1592 		/* Go around again - we're not quite ready */
1593 		sc->sc_refcnt--;
1594 		/* re-adds ub to sc_ibuff_empty and increments sc_refcnt */
1595 		ucomsubmitread(sc, ub);
1596 		mutex_exit(&sc->sc_lock);
1597 		DPRINTF("... done (not open)", 0, 0, 0, 0);
1598 		return;
1599 	}
1600 
1601 	mutex_exit(&sc->sc_lock);
1602 	if (sc->sc_methods->ucom_read != NULL) {
1603 		sc->sc_methods->ucom_read(sc->sc_parent, sc->sc_portno,
1604 		    &cp, &cc);
1605 		ub->ub_index = (u_int)(cp - ub->ub_data);
1606 	} else
1607 		ub->ub_index = 0;
1608 
1609 	ub->ub_len = cc;
1610 
1611 	mutex_enter(&sc->sc_lock);
1612 	if (sc->sc_dying) {
1613 		if (--sc->sc_refcnt < 0)
1614 			cv_broadcast(&sc->sc_detachcv);
1615 		mutex_exit(&sc->sc_lock);
1616 		DPRINTF("... dying", 0, 0, 0, 0);
1617 		return;
1618 	}
1619 
1620 	SIMPLEQ_INSERT_TAIL(&sc->sc_ibuff_full, ub, ub_link);
1621 
1622 	ucom_read_complete(sc);
1623 	mutex_exit(&sc->sc_lock);
1624 
1625 	DPRINTF("... done", 0, 0, 0, 0);
1626 }
1627 
1628 static void
1629 ucom_cleanup(struct ucom_softc *sc)
1630 {
1631 
1632 	UCOMHIST_FUNC(); UCOMHIST_CALLED();
1633 
1634 	DPRINTF("aborting pipes", 0, 0, 0, 0);
1635 
1636 	mutex_enter(&sc->sc_lock);
1637 
1638 	/* If we're dying then the detach routine will abort our pipes, etc */
1639 	if (sc->sc_dying) {
1640 		DPRINTF("... dying", 0, 0, 0, 0);
1641 
1642 		mutex_exit(&sc->sc_lock);
1643 		return;
1644 	}
1645 
1646 	mutex_exit(&sc->sc_lock);
1647 
1648 	ucom_shutdown(sc);
1649 
1650 	if (sc->sc_bulkin_pipe != NULL) {
1651 		usbd_abort_pipe(sc->sc_bulkin_pipe);
1652 	}
1653 	if (sc->sc_bulkout_pipe != NULL) {
1654 		usbd_abort_pipe(sc->sc_bulkout_pipe);
1655 	}
1656 }
1657 
1658 #endif /* NUCOM > 0 */
1659 
1660 int
1661 ucomprint(void *aux, const char *pnp)
1662 {
1663 	struct ucom_attach_args *ucaa = aux;
1664 
1665 	if (pnp)
1666 		aprint_normal("ucom at %s", pnp);
1667 	if (ucaa->ucaa_portno != UCOM_UNK_PORTNO)
1668 		aprint_normal(" portno %d", ucaa->ucaa_portno);
1669 	return UNCONF;
1670 }
1671 
1672 int
1673 ucomsubmatch(device_t parent, cfdata_t cf,
1674 	     const int *ldesc, void *aux)
1675 {
1676 	struct ucom_attach_args *ucaa = aux;
1677 
1678 	if (ucaa->ucaa_portno != UCOM_UNK_PORTNO &&
1679 	    cf->cf_loc[UCOMBUSCF_PORTNO] != UCOMBUSCF_PORTNO_DEFAULT &&
1680 	    cf->cf_loc[UCOMBUSCF_PORTNO] != ucaa->ucaa_portno)
1681 		return 0;
1682 	return config_match(parent, cf, aux);
1683 }
1684