Add basic NMEA0183 support as a tty line discipline. The line discipline

decodes NMEA messages completely transparent to userland applications, i.e.
userland can still use the NMEA stream and talk to the device.  If data
is received, a timedelta sensor suitable for ntpd is created.  The timestamp
is not very precise at the moment, use of this is experimental at best.

"get it in or we see how well the swiss people can swim" deraadt@

4 files changed, 428 insertions, 3 deletions

diff --git a/sys/conf/files b/sys/conf/files
index 1ce78a06430..07e885ed356 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1,4 +1,4 @@
-#	$OpenBSD: files,v 1.374 2006/05/28 17:21:14 uwe Exp $
+#	$OpenBSD: files,v 1.375 2006/06/01 20:10:28 mbalmer Exp $
 #	$NetBSD: files,v 1.87 1996/05/19 17:17:50 jonathan Exp $
 
 #	@(#)files.newconf	7.5 (Berkeley) 5/10/93
@@ -935,3 +935,7 @@ file net/pfkey.c			key | ipsec | tcp_signature
 file net/pfkeyv2.c			key | ipsec | tcp_signature
 file net/pfkeyv2_parsemessage.c		key | ipsec | tcp_signature
 file net/pfkeyv2_convert.c		key | ipsec | tcp_signature
+
+# NMEA0183 support
+pseudo-device nmea: tty
+file	kern/tty_nmea.c			nmea needs-flag
diff --git a/sys/kern/tty_conf.c b/sys/kern/tty_conf.c
index e5ab5c36215..5ddcc090f39 100644
--- a/sys/kern/tty_conf.c
+++ b/sys/kern/tty_conf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tty_conf.c,v 1.9 2005/12/21 12:43:49 jsg Exp $	*/
+/*	$OpenBSD: tty_conf.c,v 1.10 2006/06/01 20:10:28 mbalmer Exp $	*/
 /*	$NetBSD: tty_conf.c,v 1.18 1996/05/19 17:17:55 jonathan Exp $	*/
 
 /*-
@@ -94,6 +94,13 @@ int	stripinput(int c, struct tty *tp);
 int	stripstart(struct tty *tp);
 #endif
 
+#include "nmea.h"
+#if NNMEA > 0
+int	nmeaopen(dev_t, struct tty *);
+int	nmeaclose(struct tty *, int);
+int	nmeainput(int, struct tty *);
+#endif
+
 struct	linesw linesw[] =
 {
 	{ ttyopen, ttylclose, ttread, ttwrite, nullioctl,
@@ -141,6 +148,14 @@ struct	linesw linesw[] =
 	{ ttynodisc, ttyerrclose, ttyerrio, ttyerrio, nullioctl,
 	  ttyerrinput, ttyerrstart, nullmodem },
 #endif
+
+#if NNMEA > 0
+	{ nmeaopen, nmeaclose, ttread, ttwrite, nullioctl,
+	  nmeainput, ttstart, ttymodem },		/* 7- NMEADISC */
+#else
+	{ ttynodisc, ttyerrclose, ttyerrio, ttyerrio, nullioctl,
+	  ttyerrinput, ttyerrstart, nullmodem },
+#endif
 };
 
 int	nlinesw = sizeof (linesw) / sizeof (linesw[0]);
diff --git a/sys/kern/tty_nmea.c b/sys/kern/tty_nmea.c
new file mode 100644
index 00000000000..a6215bf3b31
--- /dev/null
+++ b/sys/kern/tty_nmea.c
@@ -0,0 +1,405 @@
+/*	$OpenBSD $*/
+
+/*
+ * Copyright (c) 2006 Marc Balmer <mbalmer@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* line discipline to decode NMEA0183 data */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/queue.h>
+#include <sys/malloc.h>
+#include <sys/sensors.h>
+#include <sys/tty.h>
+#include <sys/conf.h>
+
+#include <dev/clock_subr.h>	/* clock_subr not avail on all arches */
+
+#ifdef NMEA_DEBUG
+#define DPRINTFN(n, x)	do { if (nmeadebug > (n)) printf x; } while (0)
+int nmeadebug = 0;
+#else
+#define DPRINTFN(n, x)
+#endif
+#define DPRINTF(x)	DPRINTFN(0, x)
+
+int	nmeaopen(dev_t, struct tty *);
+int	nmeaclose(struct tty *, int);
+int	nmeainput(int, struct tty *);
+void	nmeaattach(int);
+
+#define NMEAMAX	82
+#define MAXFLDS	12
+
+/* NMEA talker identifiers */
+
+#define TI_UNK	0
+#define TI_GPS	1
+#define TI_LORC	2
+
+/* NMEA message types */
+
+#define MSG_RMC	5393731	/* recommended minimum sentence C */
+#define MSG_GGA	4671297
+#define MSG_GSA	4674369	/* satellites active */
+#define MSG_GSV	4674390	/* satellites in view */
+#define MSG_VTG	5657671	/* velocity, direction, speed */
+
+int nmea_count = 0;
+time_t nmea_last = 0;
+
+struct nmea {
+	char		cbuf[NMEAMAX];
+	struct sensor	time;
+	struct timeval	tv;			/* soft timestamp */
+	struct timespec	ts;
+	int		state;			/* state we're in */
+	int		pos;
+	int		fpos[MAXFLDS];
+	int		flds;			/* expect nr of fields */
+	int		fldcnt;			/* actual count of fields */
+	int		cksum;			/* calculated checksum */
+	int		msgcksum;		/* received cksum */
+	int		ti;			/* talker identifier */
+	int		msg;			/* NMEA msg type */
+};
+
+/* NMEA protocol state machine */
+
+void	nmea_hdlr(struct nmea *, int c);
+
+/* NMEA decoding */
+
+void	nmea_decode(struct nmea *);
+void	nmea_rmc(struct nmea *);
+
+/* helper functions */
+
+int	nmea_atoi(char *, int *);
+void	nmea_bufadd(struct nmea *, int);
+
+enum states {
+	S_SYNC = 0,
+	S_TI_1,
+	S_TI_2,
+	S_MSG,
+	S_DATA,
+	S_CKSUM
+};
+
+int
+nmeaopen(dev_t dev, struct tty *tp)
+{
+	struct nmea *np;
+
+	if (tp->t_line != NMEADISC) {
+		np = malloc(sizeof(struct nmea), M_WAITOK, M_DEVBUF);
+		tp->t_sc = (caddr_t)np;
+
+		snprintf(np->time.device, sizeof(np->time.device), "nmea%d",
+		    nmea_count++);
+		np->time.status = SENSOR_S_UNKNOWN;
+		np->time.type = SENSOR_TIMEDELTA;
+		np->time.value = 0LL;
+		np->time.rfact = 0;
+		np->time.flags = 0;
+		np->state = S_SYNC;
+	}
+
+	return linesw[0].l_open(dev, tp);
+}
+
+int
+nmeaclose(struct tty *tp, int flags)
+{
+	struct nmea *np = (struct nmea *)tp->t_sc;
+
+	tp->t_line = 0;	/* switch back to termios */
+	if (np->time.status != SENSOR_S_UNKNOWN)
+		sensor_del(&np->time);
+	free(np, M_DEVBUF);
+	nmea_count--;
+	return linesw[0].l_close(tp, flags);
+}
+
+/* scan input from tty for NMEA telegrams */
+int
+nmeainput(int c, struct tty *tp)
+{
+	struct nmea *np = (struct nmea *)tp->t_sc;
+
+	nmea_hdlr(np, c);
+
+	/* pass data to termios */
+	return linesw[0].l_rint(c, tp);
+}
+
+void
+nmeaattach(int dummy)
+{
+}
+
+/* NMEA state machine */
+void
+nmea_hdlr(struct nmea *np, int c)
+{
+	switch (np->state) {
+	case S_SYNC:
+		switch (c) {
+		case '$':
+			/* timestamp and delta refs now */
+			microtime(&np->tv);
+			nanotime(&np->ts);
+			np->pos = 0;
+			np->fldcnt = 0;
+			np->flds = 0;
+			np->cbuf[np->pos++] = c;
+			np->cksum = 0;
+			np->msgcksum = -1;
+			np->ti = TI_UNK;
+			np->state = S_TI_1;
+		}
+		break;
+	case S_TI_1:
+		nmea_bufadd(np, c);
+		np->state = S_TI_2;
+		switch (c) {
+		case 'G':
+			np->ti = TI_GPS;
+			break;
+		case 'L':
+			np->ti = TI_LORC;
+			break;
+		default:
+			np->state = S_SYNC;
+		}
+		break;
+	case S_TI_2:
+		nmea_bufadd(np, c);
+		np->state = S_SYNC;
+		switch (c) {
+		case 'P':
+			if (np->ti == TI_GPS)
+				np->state = S_MSG;
+			break;
+		case 'C':
+			if (np->ti == TI_LORC)
+				np->state = S_MSG;
+			break;
+		}
+		break;
+	case S_MSG:
+		nmea_bufadd(np, c);
+		if (np->pos == 6) {
+			np->msg = (np->cbuf[3] << 16) + (np->cbuf[4] << 8) +
+			    np->cbuf[5];
+			switch (np->msg) {
+			case MSG_RMC:
+				np->flds = 12;
+				np->state = S_DATA;
+				break;
+			default:
+				np->state = S_SYNC;
+			}
+		}
+		break;
+	case S_DATA:
+		switch (c) {
+		case '\n':
+			np->cbuf[np->pos] = '\0';
+			nmea_decode(np);
+			np->state = S_SYNC;
+			break;
+		case '*':
+			np->cbuf[np->pos++] = c;
+			np->msgcksum = 0;
+			np->state = S_CKSUM;
+			break;
+		case ',':
+			np->fpos[np->fldcnt++] = np->pos + 1;
+		default:
+			if (np->pos < NMEAMAX)
+				nmea_bufadd(np, c);
+			else
+				np->state = S_SYNC;
+		}
+		break;
+	case S_CKSUM:
+		switch (c) {
+		case '\r':
+		case '\n':
+			np->cbuf[np->pos] = '\0';
+			nmea_decode(np);
+			np->state = S_SYNC;
+			break;
+		default:
+			if (np->pos < NMEAMAX && ((c >= '0' && c<= '9') ||
+			    (c >= 'A' && c <= 'F'))) {
+				np->cbuf[np->pos++] = c;
+				if (np->msgcksum)
+					np->msgcksum <<= 4;
+				if (c >= '0' && c<= '9')
+					np->msgcksum += c - '0';
+				else if (c >= 'A' && c <= 'F')
+					np->msgcksum += 10 + c - 'A';
+			} else
+				np->state = S_SYNC;
+		}
+		break;
+	}
+}
+
+/* add a character to the buffer and update the checksum */
+void
+nmea_bufadd(struct nmea *np, int c)
+{
+	np->cbuf[np->pos++] = c;
+	np->cksum ^= c;
+}
+
+/*
+ * convert a string to a number, stop at the first non-numerical
+ * character or the end of the string.  any non-numerical character
+ * following the number other than ',' is considered an error.
+ */
+int
+nmea_atoi(char *s, int *num)
+{
+	int n;
+
+	for (n = 0; *s && *s >= '0' && *s <= '9'; s++) {
+		if (n)
+			n *= 10;
+		n += *s - '0';
+	}
+
+	if (*s && *s != ',')	/* no numeric character */
+		return (-1);
+
+	*num = n;
+	return (0);
+}
+
+void
+nmea_decode(struct nmea *np)
+{
+	switch (np->msg) {
+	case MSG_RMC:
+		nmea_rmc(np);
+		break;
+	}
+}
+
+/* Decode the minimum recommended nav info sentence (RMC) */
+void
+nmea_rmc(struct nmea *np)
+{
+	struct clock_ymdhms ymdhms;
+	time_t nmea_now;
+	int n;
+
+	if (np->fldcnt != np->flds) {
+		DPRINTF("field count mismatch\n");
+		return;
+	}
+	if (np->msgcksum >= 0 && np->cksum != np->msgcksum) {
+		DPRINTF("checksum error");
+		return;
+	}
+	np->cbuf[13] = '\0';
+	if (nmea_atoi(&np->cbuf[11], &n)) {
+		DPRINTF("error in sec\n");
+		return;
+	}
+	ymdhms.dt_sec = n;
+	np->cbuf[11] = 0;
+	if (nmea_atoi(&np->cbuf[9], &n)) {
+		DPRINTF("error in min\n");
+		return;
+	}
+	ymdhms.dt_min = n;
+	np->cbuf[9] = 0;
+	if (nmea_atoi(&np->cbuf[7], &n)) {
+		DPRINTF("error in hour\n");
+		return;
+	}
+	ymdhms.dt_hour = n;
+	if (nmea_atoi(&np->cbuf[np->fpos[8] + 4], &n)) {
+		DPRINTF("error in year\n");
+		return;
+	}
+	ymdhms.dt_year = 2000 + n;
+	np->cbuf[np->fpos[8] + 4] = '\0';
+	if (nmea_atoi(&np->cbuf[np->fpos[8] + 2], &n)) {
+		DPRINTF("error in month\n");
+		return;
+	}
+	ymdhms.dt_mon = n;
+	np->cbuf[np->fpos[8] + 2] = '\0';
+	if (nmea_atoi(&np->cbuf[np->fpos[8]], &n)) {
+		DPRINTF("error in day\n");
+		return;
+	}
+	ymdhms.dt_day = n;
+	nmea_now = clock_ymdhms_to_secs(&ymdhms);
+	if (nmea_now <= nmea_last) {
+		DPRINTF("time not monotonically increasing\n");
+		return;
+	}
+	nmea_last = nmea_now;
+	np->time.value = (np->ts.tv_sec - nmea_now)
+	    * 1000000000 + np->ts.tv_nsec;
+	np->time.tv.tv_sec = np->tv.tv_sec;
+	np->time.tv.tv_usec = np->tv.tv_usec;
+	if (np->time.status == SENSOR_S_UNKNOWN) {
+		strlcpy(np->time.desc, np->ti == TI_GPS ? "GPS  GPS" :
+		    "LORC Loran-C", sizeof(np->time.desc));
+		switch (np->cbuf[np->fpos[11]]) {
+		case 'S':
+			strlcat(np->time.desc, " simulated",
+			    sizeof(np->time.desc));
+			break;
+		case 'E':
+			strlcat(np->time.desc, " estimated",
+			    sizeof(np->time.desc));
+			break;
+		case 'A':
+			strlcat(np->time.desc, " autonomous",
+			    sizeof(np->time.desc));
+			break;
+		case 'D':
+			strlcat(np->time.desc, " differential",
+			    sizeof(np->time.desc));
+			break;
+		case 'N':
+			strlcat(np->time.desc, " not valid",
+			    sizeof(np->time.desc));
+			break;
+		}
+		np->time.status = SENSOR_S_OK;
+		sensor_add(&np->time);
+	}
+	switch (np->cbuf[np->fpos[1]]) {
+	case 'A':
+		np->time.status = SENSOR_S_OK;
+		break;
+	case 'V':
+		np->time.status = SENSOR_S_WARN;
+		break;
+	default:
+		DPRINTF("unknown warning indication\n");
+	}
+}
diff --git a/sys/sys/ttycom.h b/sys/sys/ttycom.h
index ad0f3579d1e..0d8e4ba4d10 100644
--- a/sys/sys/ttycom.h
+++ b/sys/sys/ttycom.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ttycom.h,v 1.7 2006/04/27 19:30:28 deraadt Exp $	*/
+/*	$OpenBSD: ttycom.h,v 1.8 2006/06/01 20:10:28 mbalmer Exp $	*/
 /*	$NetBSD: ttycom.h,v 1.4 1996/05/19 17:17:53 jonathan Exp $	*/
 
 /*-
@@ -142,5 +142,6 @@ struct tstamps {
 #define	SLIPDISC	4		/* serial IP discipline */
 #define	PPPDISC		5		/* ppp discipline */
 #define	STRIPDISC	6		/* metricom wireless IP discipline */
+#define	NMEADISC	7		/* NMEA0183 discipline */
 
 #endif /* !_SYS_TTYCOM_H_ */