[LinuxPPS] another refclock_nmea patch ([Bug 610] Generic NMEA GPS Receiver driver w/ PPS expects PPS after NMEA data)

[Udo van den Heuvel]

Hello,

I got this feedback from Frank:

I looked at the path and wonder if the leap frogging goto's could be
avoided.
Maybe a structure like:

 set ppshandle invalid
 open(PPSDEVICE
 if (ok) {
   if (create..(ppsfd...) == ok) {
     log success for PPS device
   } else {
     close device
   }
 }

 if (handle (still) invalid) {
     if (create..(main device == ok) {
       log success for main device
     } else {
       log failure for PPS support
     }
 }

I think this is easier to follow than leapfrogging gotos.



So I changed the code once more. See the attachment. Does it look OK?


Udo
-------------- next part --------------
--- org.ntp-4.2.4p2/ntpd/refclock_nmea.c	2006-06-06 22:16:53.000000000 +0200
+++ ntp-4.2.4p2/ntpd/refclock_nmea.c	2007-11-03 15:06:04.000000000 +0100
@@ -61,6 +61,7 @@
 # define DEVICE "COM%d:" 	/* COM 1 - 3 supported */
 #else
 # define DEVICE	"/dev/gps%d"	/* name of radio device */
+# define DEVICEPPS "/dev/gpspps%d" /* name of alternate PPS radio device */
 #endif
 #define	SPEED232	B4800	/* uart speed (4800 bps) */
 #define	PRECISION	(-9)	/* precision assumed (about 2 ms) */
@@ -71,6 +72,7 @@
 #define RANGEGATE	500000	/* range gate (ns) */
 
 #define LENNMEA		75	/* min timecode length */
+#define LENPPS		PPS_MAX_NAME_LEN
 
 /*
  * Tables to compute the ddd of year form icky dd/mm timecode. Viva la
@@ -230,13 +232,33 @@
 	 * Start the PPSAPI interface if it is there. Default to use
 	 * the assert edge and do not enable the kernel hardpps.
 	 */
-	if (time_pps_create(fd, &up->handle) < 0) {
-		up->handle = 0;
-		msyslog(LOG_ERR,
-		    "refclock_nmea: time_pps_create failed: %m");
-		return (1);
+	msyslog(LOG_ERR, "refclock_nmea: found GPS source \"%s\"", device);
+ 	fd = -1;
+	(void) sprintf(device, DEVICEPPS, unit);
+        fd = open(device, O_RDWR);
+        if (fd > 0) {	/* /dev/gpspps0 exists */
+		msyslog(LOG_ERR, "refclock_nmea: try \"%s\" for PPS", device);
+		if (time_pps_create(fd, &up->handle) == 0) {
+			msyslog(LOG_INFO, "refclock_nmea: found PPS source \"%s\"", device);
+			return(nmea_ppsapi(peer, 0, 0));
+		}
+		else close(fd);
 	}
-	return(nmea_ppsapi(peer, 0, 0));
+
+	if (fd < 0) {
+		(void) sprintf(device, DEVICE, unit);
+		msyslog(LOG_ERR, "refclock_nmea: try GPS device \"%s\" for PPS", device);
+		if (time_pps_create(pp->io.fd, &up->handle) == 0) {
+			msyslog(LOG_INFO, "refclock_nmea: found PPS source \"%s\"", device);
+			return(nmea_ppsapi(peer, 0, 0));
+		}
+	}
+
+	/* No luck, no PPS unit available! */
+	up->handle = -1;
+	msyslog(LOG_ERR, "refclock_nmea: no PPS devices found at " DEVICE " nor " 
+		DEVICEPPS ": %m", unit, unit);
+	return (1);
 #else
 	return (1);
 #endif /* HAVE_PPSAPI */
@@ -257,8 +279,7 @@
 	pp = peer->procptr;
 	up = (struct nmeaunit *)pp->unitptr;
 #ifdef HAVE_PPSAPI
-	if (up->handle != 0)
-		time_pps_destroy(up->handle);
+	time_pps_destroy(up->handle);
 #endif /* HAVE_PPSAPI */
 	io_closeclock(&pp->io);
 	free(up);
@@ -366,7 +387,7 @@
 	/*
 	 * Convert the timespec nanoseconds field to ntp l_fp units.
 	 */ 
-	if (up->handle == 0)
+	if (up->handle == -1)
 		return (0);
 	timeout.tv_sec = 0;
 	timeout.tv_nsec = 0;