xref: /openbsd/sys/dev/usb/udcf.c (revision 5dea098c)
1 /*	$OpenBSD: udcf.c,v 1.65 2022/07/02 08:50:42 visa Exp $ */
2 
3 /*
4  * Copyright (c) 2006, 2007, 2008 Marc Balmer <mbalmer@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/param.h>
20 #include <sys/systm.h>
21 #include <sys/kernel.h>
22 #include <sys/device.h>
23 #include <sys/time.h>
24 #include <sys/sensors.h>
25 #include <sys/timeout.h>
26 
27 #include <dev/usb/usb.h>
28 #include <dev/usb/usbdi.h>
29 #include <dev/usb/usbdi_util.h>
30 #include <dev/usb/usbdevs.h>
31 
32 #ifdef UDCF_DEBUG
33 #define DPRINTFN(n, x)	do { if (udcfdebug > (n)) printf x; } while (0)
34 int udcfdebug = 0;
35 #else
36 #define DPRINTFN(n, x)
37 #endif
38 #define DPRINTF(x)	DPRINTFN(0, x)
39 
40 #define UDCF_READ_IDX	0x1f
41 
42 #define UDCF_CTRL_IDX	0x33
43 #define UDCF_CTRL_VAL	0x98
44 
45 #define FT232R_RESET	0x00	/* reset USB request */
46 #define FT232R_STATUS	0x05	/* get modem status USB request */
47 #define FT232R_RI	0x40	/* ring indicator */
48 
49 /* max. skew of received time diff vs. measured time diff in percent. */
50 #define MAX_SKEW	5
51 
52 #define CLOCK_DCF77	"DCF77"
53 
54 struct udcf_softc {
55 	struct device		sc_dev;		/* base device */
56 	struct usbd_device	*sc_udev;	/* USB device */
57 	struct usbd_interface	*sc_iface;	/* data interface */
58 
59 	struct timeout		sc_to;
60 	struct usb_task		sc_task;
61 
62 	struct timeout		sc_bv_to;	/* bit-value detect */
63 	struct timeout		sc_db_to;	/* debounce */
64 	struct timeout		sc_mg_to;	/* minute-gap detect */
65 	struct timeout		sc_sl_to;	/* signal-loss detect */
66 	struct timeout		sc_it_to;	/* invalidate time */
67 	struct usb_task		sc_bv_task;
68 	struct usb_task		sc_mg_task;
69 	struct usb_task		sc_sl_task;
70 
71 	usb_device_request_t	sc_req;
72 
73 	int			sc_sync;	/* 1 during sync */
74 	u_int64_t		sc_mask;	/* 64 bit mask */
75 	u_int64_t		sc_tbits;	/* Time bits */
76 	int			sc_minute;
77 	int			sc_level;
78 	time_t			sc_last_mg;
79 	int			(*sc_signal)(struct udcf_softc *);
80 
81 	time_t			sc_current;	/* current time */
82 	time_t			sc_next;	/* time to become valid next */
83 	time_t			sc_last;
84 	int			sc_nrecv;	/* consecutive valid times */
85 	struct timeval		sc_last_tv;	/* uptime of last valid time */
86 	struct ksensor		sc_sensor;
87 #ifdef UDCF_DEBUG
88 	struct ksensor		sc_skew;	/* recv vs local skew */
89 #endif
90 	struct ksensordev	sc_sensordev;
91 };
92 
93 /* timeouts in milliseconds: */
94 #define	T_BV		150	/* bit value detection (150ms) */
95 #define	T_SYNC		950	/* sync (950ms) */
96 #define	T_MG		1500	/* minute gap detection (1500ms) */
97 #define	T_MGSYNC	450	/* resync after a minute gap (450ms) */
98 #define	T_SL		3000	/* detect signal loss (3sec) */
99 #define	T_WAIT		5000	/* wait (5sec) */
100 #define	T_WARN		300000	/* degrade sensor status to warning (5min) */
101 #define	T_CRIT		900000	/* degrade sensor status to critical (15min) */
102 
103 void	udcf_intr(void *);
104 void	udcf_probe(void *);
105 
106 void	udcf_bv_intr(void *);
107 void	udcf_mg_intr(void *);
108 void	udcf_sl_intr(void *);
109 void	udcf_it_intr(void *);
110 void	udcf_bv_probe(void *);
111 void	udcf_mg_probe(void *);
112 void	udcf_sl_probe(void *);
113 
114 int udcf_match(struct device *, void *, void *);
115 void udcf_attach(struct device *, struct device *, void *);
116 int udcf_detach(struct device *, int);
117 
118 int udcf_nc_signal(struct udcf_softc *);
119 int udcf_nc_init_hw(struct udcf_softc *);
120 int udcf_ft232r_signal(struct udcf_softc *);
121 int udcf_ft232r_init_hw(struct udcf_softc *);
122 
123 struct cfdriver udcf_cd = {
124 	NULL, "udcf", DV_DULL
125 };
126 
127 const struct cfattach udcf_ca = {
128 	sizeof(struct udcf_softc), udcf_match, udcf_attach, udcf_detach,
129 };
130 
131 static const struct usb_devno udcf_devs[] = {
132 	{ USB_VENDOR_GUDE, USB_PRODUCT_GUDE_DCF },
133 	{ USB_VENDOR_FTDI, USB_PRODUCT_FTDI_DCF }
134 };
135 
136 int
137 udcf_match(struct device *parent, void *match, void *aux)
138 {
139 	struct usb_attach_arg		*uaa = aux;
140 
141 	if (uaa->iface == NULL)
142 		return UMATCH_NONE;
143 
144 	return (usb_lookup(udcf_devs, uaa->vendor, uaa->product) != NULL ?
145 	    UMATCH_VENDOR_PRODUCT : UMATCH_NONE);
146 }
147 
148 void
149 udcf_attach(struct device *parent, struct device *self, void *aux)
150 {
151 	struct udcf_softc		*sc = (struct udcf_softc *)self;
152 	struct usb_attach_arg		*uaa = aux;
153 	struct usbd_device		*dev = uaa->device;
154 	struct usbd_interface		*iface;
155 	usbd_status			 err;
156 
157 	switch (uaa->product) {
158 	case USB_PRODUCT_GUDE_DCF:
159 		sc->sc_signal = udcf_nc_signal;
160 		strlcpy(sc->sc_sensor.desc, "DCF77",
161 		    sizeof(sc->sc_sensor.desc));
162 		break;
163 	case USB_PRODUCT_FTDI_DCF:
164 		sc->sc_signal = udcf_ft232r_signal;
165 		strlcpy(sc->sc_sensor.desc, "DCF77",
166 		    sizeof(sc->sc_sensor.desc));
167 		break;
168 	}
169 
170 	usb_init_task(&sc->sc_task, udcf_probe, sc, USB_TASK_TYPE_GENERIC);
171 	usb_init_task(&sc->sc_bv_task, udcf_bv_probe, sc, USB_TASK_TYPE_GENERIC);
172 	usb_init_task(&sc->sc_mg_task, udcf_mg_probe, sc, USB_TASK_TYPE_GENERIC);
173 	usb_init_task(&sc->sc_sl_task, udcf_sl_probe, sc, USB_TASK_TYPE_GENERIC);
174 
175 	timeout_set(&sc->sc_to, udcf_intr, sc);
176 	timeout_set(&sc->sc_bv_to, udcf_bv_intr, sc);
177 	timeout_set(&sc->sc_mg_to, udcf_mg_intr, sc);
178 	timeout_set(&sc->sc_sl_to, udcf_sl_intr, sc);
179 	timeout_set(&sc->sc_it_to, udcf_it_intr, sc);
180 
181 	strlcpy(sc->sc_sensordev.xname, sc->sc_dev.dv_xname,
182 	    sizeof(sc->sc_sensordev.xname));
183 
184 	sc->sc_sensor.type = SENSOR_TIMEDELTA;
185 	sc->sc_sensor.status = SENSOR_S_UNKNOWN;
186 	sensor_attach(&sc->sc_sensordev, &sc->sc_sensor);
187 
188 #ifdef UDCF_DEBUG
189 	sc->sc_skew.type = SENSOR_TIMEDELTA;
190 	sc->sc_skew.status = SENSOR_S_UNKNOWN;
191 	strlcpy(sc->sc_skew.desc, "local clock skew",
192 	    sizeof(sc->sc_skew.desc));
193 	sensor_attach(&sc->sc_sensordev, &sc->sc_skew);
194 #endif
195 	sensordev_install(&sc->sc_sensordev);
196 
197 	sc->sc_udev = dev;
198 	if ((err = usbd_device2interface_handle(dev, 0, &iface))) {
199 		DPRINTF(("%s: failed to get interface, err=%s\n",
200 		    sc->sc_dev.dv_xname, usbd_errstr(err)));
201 		goto fishy;
202 	}
203 
204 	sc->sc_iface = iface;
205 
206 	sc->sc_level = 0;
207 	sc->sc_minute = 0;
208 	sc->sc_last_mg = 0L;
209 
210 	sc->sc_sync = 1;
211 
212 	sc->sc_current = 0L;
213 	sc->sc_next = 0L;
214 	sc->sc_nrecv = 0;
215 	sc->sc_last = 0L;
216 	sc->sc_last_tv.tv_sec = 0L;
217 
218 	switch (uaa->product) {
219 	case USB_PRODUCT_GUDE_DCF:
220 		if (udcf_nc_init_hw(sc))
221 			goto fishy;
222 		break;
223 	case USB_PRODUCT_FTDI_DCF:
224 		if (udcf_ft232r_init_hw(sc))
225 			goto fishy;
226 		break;
227 	}
228 
229 	/* Give the receiver some slack to stabilize */
230 	timeout_add_msec(&sc->sc_to, T_WAIT);
231 
232 	/* Detect signal loss */
233 	timeout_add_msec(&sc->sc_sl_to, T_WAIT + T_SL);
234 
235 	DPRINTF(("synchronizing\n"));
236 	return;
237 
238 fishy:
239 	DPRINTF(("udcf_attach failed\n"));
240 	usbd_deactivate(sc->sc_udev);
241 }
242 
243 int
244 udcf_detach(struct device *self, int flags)
245 {
246 	struct udcf_softc	*sc = (struct udcf_softc *)self;
247 
248 	if (timeout_initialized(&sc->sc_to))
249 		timeout_del(&sc->sc_to);
250 	if (timeout_initialized(&sc->sc_bv_to))
251 		timeout_del(&sc->sc_bv_to);
252 	if (timeout_initialized(&sc->sc_mg_to))
253 		timeout_del(&sc->sc_mg_to);
254 	if (timeout_initialized(&sc->sc_sl_to))
255 		timeout_del(&sc->sc_sl_to);
256 	if (timeout_initialized(&sc->sc_it_to))
257 		timeout_del(&sc->sc_it_to);
258 
259 	/* Unregister the clock with the kernel */
260 	sensordev_deinstall(&sc->sc_sensordev);
261 	usb_rem_task(sc->sc_udev, &sc->sc_task);
262 	usb_rem_task(sc->sc_udev, &sc->sc_bv_task);
263 	usb_rem_task(sc->sc_udev, &sc->sc_mg_task);
264 	usb_rem_task(sc->sc_udev, &sc->sc_sl_task);
265 
266 	return 0;
267 }
268 
269 /* udcf_intr runs in an interrupt context */
270 void
271 udcf_intr(void *xsc)
272 {
273 	struct udcf_softc *sc = xsc;
274 	usb_add_task(sc->sc_udev, &sc->sc_task);
275 }
276 
277 /* bit value detection */
278 void
279 udcf_bv_intr(void *xsc)
280 {
281 	struct udcf_softc *sc = xsc;
282 	usb_add_task(sc->sc_udev, &sc->sc_bv_task);
283 }
284 
285 /* minute gap detection */
286 void
287 udcf_mg_intr(void *xsc)
288 {
289 	struct udcf_softc *sc = xsc;
290 	usb_add_task(sc->sc_udev, &sc->sc_mg_task);
291 }
292 
293 /* signal loss detection */
294 void
295 udcf_sl_intr(void *xsc)
296 {
297 	struct udcf_softc *sc = xsc;
298 	usb_add_task(sc->sc_udev, &sc->sc_sl_task);
299 }
300 
301 /*
302  * initialize the Expert mouseCLOCK USB devices, they use a NetCologne
303  * chip to interface the receiver.  Power must be supplied to the
304  * receiver and the receiver must be turned on.
305  */
306 int
307 udcf_nc_init_hw(struct udcf_softc *sc)
308 {
309 	usbd_status			 err;
310 	usb_device_request_t		 req;
311 	uWord				 result;
312 	int				 actlen;
313 
314 	/* Prepare the USB request to probe the value */
315 	sc->sc_req.bmRequestType = UT_READ_VENDOR_DEVICE;
316 	sc->sc_req.bRequest = 1;
317 	USETW(sc->sc_req.wValue, 0);
318 	USETW(sc->sc_req.wIndex, UDCF_READ_IDX);
319 	USETW(sc->sc_req.wLength, 1);
320 
321 	req.bmRequestType = UT_WRITE_VENDOR_DEVICE;
322 	req.bRequest = 0;
323 	USETW(req.wValue, 0);
324 	USETW(req.wIndex, 0);
325 	USETW(req.wLength, 0);
326 	if ((err = usbd_do_request_flags(sc->sc_udev, &req, &result,
327 	    USBD_SHORT_XFER_OK, &actlen, USBD_DEFAULT_TIMEOUT))) {
328 		DPRINTF(("failed to turn on power for receiver\n"));
329 		return -1;
330 	}
331 
332 	req.bmRequestType = UT_WRITE_VENDOR_DEVICE;
333 	req.bRequest = 0;
334 	USETW(req.wValue, UDCF_CTRL_VAL);
335 	USETW(req.wIndex, UDCF_CTRL_IDX);
336 	USETW(req.wLength, 0);
337 	if ((err = usbd_do_request_flags(sc->sc_udev, &req, &result,
338 	    USBD_SHORT_XFER_OK, &actlen, USBD_DEFAULT_TIMEOUT))) {
339 		DPRINTF(("failed to turn on receiver\n"));
340 		return -1;
341 	}
342 	return 0;
343 }
344 
345 /*
346  * initialize the Expert mouseCLOCK USB II devices, they use an FTDI
347  * FT232R chip to interface the receiver.  Only reset the chip.
348  */
349 int
350 udcf_ft232r_init_hw(struct udcf_softc *sc)
351 {
352 	usbd_status		err;
353 	usb_device_request_t	req;
354 
355 	req.bmRequestType = UT_WRITE_VENDOR_DEVICE;
356 	req.bRequest = FT232R_RESET;
357 	/* 0 resets the SIO */
358 	USETW(req.wValue,FT232R_RESET);
359 	USETW(req.wIndex, 0);
360 	USETW(req.wLength, 0);
361 	err = usbd_do_request(sc->sc_udev, &req, NULL);
362 	if (err) {
363 		DPRINTF(("failed to reset ftdi\n"));
364 		return -1;
365 	}
366 	return 0;
367 }
368 
369 /*
370  * return 1 during high-power-, 0 during low-power-emission
371  * If bit 0 is set, the transmitter emits at full power.
372  * During the low-power emission we decode a zero bit.
373  */
374 int
375 udcf_nc_signal(struct udcf_softc *sc)
376 {
377 	int		actlen;
378 	unsigned char	data;
379 
380 	if (usbd_do_request_flags(sc->sc_udev, &sc->sc_req, &data,
381 	    USBD_SHORT_XFER_OK, &actlen, USBD_DEFAULT_TIMEOUT))
382 		/* This happens if we pull the receiver */
383 		return -1;
384 	return data & 0x01;
385 }
386 
387 /* pick up the signal level through the FTDI FT232R chip */
388 int
389 udcf_ft232r_signal(struct udcf_softc *sc)
390 {
391 	usb_device_request_t	req;
392 	int			actlen;
393 	u_int16_t		data;
394 
395 	req.bmRequestType = UT_READ_VENDOR_DEVICE;
396 	req.bRequest = FT232R_STATUS;
397 	USETW(req.wValue, 0);
398 	USETW(req.wIndex, 0);
399 	USETW(req.wLength, 2);
400 	if (usbd_do_request_flags(sc->sc_udev, &req, &data,
401 	    USBD_SHORT_XFER_OK, &actlen, USBD_DEFAULT_TIMEOUT)) {
402 		DPRINTFN(2, ("error reading ftdi modem status\n"));
403 		return -1;
404 	}
405 	DPRINTFN(2, ("ftdi status 0x%04x\n", data));
406 	return data & FT232R_RI ? 0 : 1;
407 }
408 
409 /* udcf_probe runs in a process context. */
410 void
411 udcf_probe(void *xsc)
412 {
413 	struct udcf_softc	*sc = xsc;
414 	struct timespec		 now;
415 	int			 data;
416 
417 	if (usbd_is_dying(sc->sc_udev))
418 		return;
419 
420 	data = sc->sc_signal(sc);
421 	if (data == -1)
422 		return;
423 
424 	if (data) {
425 		sc->sc_level = 1;
426 		timeout_add(&sc->sc_to, 1);
427 		return;
428 	}
429 
430 	if (sc->sc_level == 0)
431 		return;
432 
433 	/* the beginning of a second */
434 	sc->sc_level = 0;
435 	if (sc->sc_minute == 1) {
436 		if (sc->sc_sync) {
437 			DPRINTF(("start collecting bits\n"));
438 			sc->sc_sync = 0;
439 		} else {
440 			/* provide the timedelta */
441 			microtime(&sc->sc_sensor.tv);
442 			nanotime(&now);
443 			sc->sc_current = sc->sc_next;
444 			sc->sc_sensor.value = (int64_t)(now.tv_sec -
445 			    sc->sc_current) * 1000000000LL + now.tv_nsec;
446 
447 			sc->sc_sensor.status = SENSOR_S_OK;
448 
449 			/*
450 			 * if no valid time information is received
451 			 * during the next 5 minutes, the sensor state
452 			 * will be degraded to SENSOR_S_WARN
453 			 */
454 			timeout_add_msec(&sc->sc_it_to, T_WARN);
455 		}
456 		sc->sc_minute = 0;
457 	}
458 
459 	timeout_add_msec(&sc->sc_to, T_SYNC);	/* resync in 950 ms */
460 
461 	/* no clock and bit detection during sync */
462 	if (!sc->sc_sync) {
463 		/* detect bit value */
464 		timeout_add_msec(&sc->sc_bv_to, T_BV);
465 	}
466 	timeout_add_msec(&sc->sc_mg_to, T_MG);	/* detect minute gap */
467 	timeout_add_msec(&sc->sc_sl_to, T_SL);	/* detect signal loss */
468 }
469 
470 /* detect the bit value */
471 void
472 udcf_bv_probe(void *xsc)
473 {
474 	struct udcf_softc	*sc = xsc;
475 	int			 data;
476 
477 	if (usbd_is_dying(sc->sc_udev))
478 		return;
479 
480 	data = sc->sc_signal(sc);
481 	if (data == -1) {
482 		DPRINTF(("bit detection failed\n"));
483 		return;
484 	}
485 
486 	DPRINTFN(1, (data ? "0" : "1"));
487 	if (!(data))
488 		sc->sc_tbits |= sc->sc_mask;
489 	sc->sc_mask <<= 1;
490 }
491 
492 /* detect the minute gap */
493 void
494 udcf_mg_probe(void *xsc)
495 {
496 	struct udcf_softc	*sc = xsc;
497 	struct clock_ymdhms	 ymdhm;
498 	struct timeval		 monotime;
499 	int			 tdiff_recv, tdiff_local;
500 	int			 skew;
501 	int			 minute_bits, hour_bits, day_bits;
502 	int			 month_bits, year_bits, wday;
503 	int			 p1, p2, p3;
504 	int			 p1_bit, p2_bit, p3_bit;
505 	int			 r_bit, a1_bit, a2_bit, z1_bit, z2_bit;
506 	int			 s_bit, m_bit;
507 	u_int32_t		 parity = 0x6996;
508 
509 	if (sc->sc_sync) {
510 		sc->sc_minute = 1;
511 		goto cleanbits;
512 	}
513 
514 	if (gettime() - sc->sc_last_mg < 57) {
515 		DPRINTF(("\nunexpected gap, resync\n"));
516 		sc->sc_sync = sc->sc_minute = 1;
517 		goto cleanbits;
518 	}
519 
520 	/* extract bits w/o parity */
521 	m_bit = sc->sc_tbits & 1;
522 	r_bit = sc->sc_tbits >> 15 & 1;
523 	a1_bit = sc->sc_tbits >> 16 & 1;
524 	z1_bit = sc->sc_tbits >> 17 & 1;
525 	z2_bit = sc->sc_tbits >> 18 & 1;
526 	a2_bit = sc->sc_tbits >> 19 & 1;
527 	s_bit = sc->sc_tbits >> 20 & 1;
528 	p1_bit = sc->sc_tbits >> 28 & 1;
529 	p2_bit = sc->sc_tbits >> 35 & 1;
530 	p3_bit = sc->sc_tbits >> 58 & 1;
531 
532 	minute_bits = sc->sc_tbits >> 21 & 0x7f;
533 	hour_bits = sc->sc_tbits >> 29 & 0x3f;
534 	day_bits = sc->sc_tbits >> 36 & 0x3f;
535 	wday = (sc->sc_tbits >> 42) & 0x07;
536 	month_bits = sc->sc_tbits >> 45 & 0x1f;
537 	year_bits = sc->sc_tbits >> 50 & 0xff;
538 
539 	/* validate time information */
540 	p1 = (parity >> (minute_bits & 0x0f) & 1) ^
541 	    (parity >> (minute_bits >> 4) & 1);
542 
543 	p2 = (parity >> (hour_bits & 0x0f) & 1) ^
544 	    (parity >> (hour_bits >> 4) & 1);
545 
546 	p3 = (parity >> (day_bits & 0x0f) & 1) ^
547 	    (parity >> (day_bits >> 4) & 1) ^
548 	    ((parity >> wday) & 1) ^ (parity >> (month_bits & 0x0f) & 1) ^
549 	    (parity >> (month_bits >> 4) & 1) ^
550 	    (parity >> (year_bits & 0x0f) & 1) ^
551 	    (parity >> (year_bits >> 4) & 1);
552 
553 	if (m_bit == 0 && s_bit == 1 && p1 == p1_bit && p2 == p2_bit &&
554 	    p3 == p3_bit && (z1_bit ^ z2_bit)) {
555 
556 		/* Decode time */
557 		if ((ymdhm.dt_year = 2000 + FROMBCD(year_bits)) > 2037) {
558 			DPRINTF(("year out of range, resync\n"));
559 			sc->sc_sync = 1;
560 			goto cleanbits;
561 		}
562 		ymdhm.dt_min = FROMBCD(minute_bits);
563 		ymdhm.dt_hour = FROMBCD(hour_bits);
564 		ymdhm.dt_day = FROMBCD(day_bits);
565 		ymdhm.dt_mon = FROMBCD(month_bits);
566 		ymdhm.dt_sec = 0;
567 
568 		sc->sc_next = clock_ymdhms_to_secs(&ymdhm);
569 		getmicrouptime(&monotime);
570 
571 		/* convert to coordinated universal time */
572 		sc->sc_next -= z1_bit ? 7200 : 3600;
573 
574 		DPRINTF(("\n%02d.%02d.%04d %02d:%02d:00 %s",
575 		    ymdhm.dt_day, ymdhm.dt_mon, ymdhm.dt_year,
576 		    ymdhm.dt_hour, ymdhm.dt_min, z1_bit ? "CEST" : "CET"));
577 		DPRINTF((r_bit ? ", call bit" : ""));
578 		DPRINTF((a1_bit ? ", dst chg ann." : ""));
579 		DPRINTF((a2_bit ? ", leap sec ann." : ""));
580 		DPRINTF(("\n"));
581 
582 		if (sc->sc_last) {
583 			tdiff_recv = sc->sc_next - sc->sc_last;
584 			tdiff_local = monotime.tv_sec - sc->sc_last_tv.tv_sec;
585 			skew = abs(tdiff_local - tdiff_recv);
586 #ifdef UDCF_DEBUG
587 			if (sc->sc_skew.status == SENSOR_S_UNKNOWN)
588 				sc->sc_skew.status = SENSOR_S_CRIT;
589 			sc->sc_skew.value = skew * 1000000000LL;
590 			getmicrotime(&sc->sc_skew.tv);
591 #endif
592 			DPRINTF(("local = %d, recv = %d, skew = %d\n",
593 			    tdiff_local, tdiff_recv, skew));
594 
595 			if (skew && skew * 100LL / tdiff_local > MAX_SKEW) {
596 				DPRINTF(("skew out of tolerated range\n"));
597 				goto cleanbits;
598 			} else {
599 				if (sc->sc_nrecv < 2) {
600 					sc->sc_nrecv++;
601 					DPRINTF(("got frame %d\n",
602 					    sc->sc_nrecv));
603 				} else {
604 					DPRINTF(("data is valid\n"));
605 					sc->sc_minute = 1;
606 				}
607 			}
608 		} else {
609 			DPRINTF(("received the first frame\n"));
610 			sc->sc_nrecv = 1;
611 		}
612 
613 		/* record the time received and when it was received */
614 		sc->sc_last = sc->sc_next;
615 		sc->sc_last_tv.tv_sec = monotime.tv_sec;
616 	} else {
617 		DPRINTF(("\nparity error, resync\n"));
618 		sc->sc_sync = sc->sc_minute = 1;
619 	}
620 
621 cleanbits:
622 	timeout_add_msec(&sc->sc_to, T_MGSYNC);	/* re-sync in 450 ms */
623 	sc->sc_last_mg = gettime();
624 	sc->sc_tbits = 0LL;
625 	sc->sc_mask = 1LL;
626 }
627 
628 /* detect signal loss */
629 void
630 udcf_sl_probe(void *xsc)
631 {
632 	struct udcf_softc *sc = xsc;
633 
634 	if (usbd_is_dying(sc->sc_udev))
635 		return;
636 
637 	DPRINTF(("no signal\n"));
638 	sc->sc_sync = 1;
639 	timeout_add_msec(&sc->sc_to, T_WAIT);
640 	timeout_add_msec(&sc->sc_sl_to, T_WAIT + T_SL);
641 }
642 
643 /* invalidate timedelta (called in an interrupt context) */
644 void
645 udcf_it_intr(void *xsc)
646 {
647 	struct udcf_softc *sc = xsc;
648 
649 	if (usbd_is_dying(sc->sc_udev))
650 		return;
651 
652 	if (sc->sc_sensor.status == SENSOR_S_OK) {
653 		sc->sc_sensor.status = SENSOR_S_WARN;
654 		/*
655 		 * further degrade in 15 minutes if we dont receive any new
656 		 * time information
657 		 */
658 		timeout_add_msec(&sc->sc_it_to, T_CRIT);
659 	} else {
660 		sc->sc_sensor.status = SENSOR_S_CRIT;
661 		sc->sc_nrecv = 0;
662 	}
663 }
664