/*
* This driver supports the Spectracom Model 8170 and Netclock/2 WWVB
* Synchronized Clocks and the Netclock/GPS Master Clock. Both the WWVB
* and GPS clocks have proven reliable sources of time; however, the
* WWVB clocks have proven vulnerable to high ambient conductive RF
* interference. The claimed accuracy of the WWVB clocks is 100 us
* relative to the broadcast signal, while the claimed accuracy of the
* GPS clock is 50 ns; however, in most cases the actual accuracy is
* limited by the resolution of the timecode and the latencies of the
* serial interface and operating system.
*
* The WWVB and GPS clocks should be configured for 24-hour display,
* AUTO DST off, time zone 0 (UTC), data format 0 or 2 (see below) and
* baud rate 9600. If the clock is to used as the source for the IRIG
* Audio Decoder (refclock_irig.c in this distribution), it should be
* configured for AM IRIG output and IRIG format 1 (IRIG B with
* signature control). The GPS clock can be configured either to respond
* to a 'T' poll character or left running continuously.
*
* There are two timecode formats used by these clocks. Format 0, which
* is available with both the Netclock/2 and 8170, and format 2, which
* is available only with the Netclock/2, specially modified 8170 and
* GPS.
*
* Format 0 (22 ASCII printing characters):
*
* <cr><lf>i ddd hh:mm:ss TZ=zz<cr><lf>
*
* on-time = first <cr>
* hh:mm:ss = hours, minutes, seconds
* i = synchronization flag (' ' = in synch, '?' = out of synch)
*
* The alarm condition is indicated by other than ' ' at i, which occurs
* during initial synchronization and when received signal is lost for
* about ten hours.
*
* Format 2 (24 ASCII printing characters):
*
* <cr><lf>iqyy ddd hh:mm:ss.fff ld
*
* on-time = <cr>
* i = synchronization flag (' ' = in synch, '?' = out of synch)
* q = quality indicator (' ' = locked, 'A'...'D' = unlocked)
* yy = year (as broadcast)
* ddd = day of year
* hh:mm:ss.fff = hours, minutes, seconds, milliseconds
*
* The alarm condition is indicated by other than ' ' at i, which occurs
* during initial synchronization and when received signal is lost for
* about ten hours. The unlock condition is indicated by other than ' '
* at q.
*
* The q is normally ' ' when the time error is less than 1 ms and a
* character in the set 'A'...'D' when the time error is less than 10,
* 100, 500 and greater than 500 ms respectively. The l is normally ' ',
* but is set to 'L' early in the month of an upcoming UTC leap second
* and reset to ' ' on the first day of the following month. The d is
* set to 'S' for standard time 'I' on the day preceding a switch to
* daylight time, 'D' for daylight time and 'O' on the day preceding a
* switch to standard time. The start bit of the first <cr> is
* synchronized to the indicated time as returned.
*
* This driver does not need to be told which format is in use - it
* figures out which one from the length of the message. The driver
* makes no attempt to correct for the intrinsic jitter of the radio
* itself, which is a known problem with the older radios.
*
* PPS Signal Processing
*
* When PPS signal processing is enabled, and when the system clock has
* been set by this or another driver and the PPS signal offset is
* within 0.4 s of the system clock offset, the PPS signal replaces the
* timecode for as long as the PPS signal is active. If for some reason
* the PPS signal fails for one or more poll intervals, the driver
* reverts to the timecode. If the timecode fails for one or more poll
* intervals, the PPS signal is disconnected.
*
* Fudge Factors
*
* This driver can retrieve a table of quality data maintained
* internally by the Netclock/2 clock. If flag4 of the fudge
* configuration command is set to 1, the driver will retrieve this
* table and write it to the clockstats file when the first timecode
* message of a new day is received.
*
* PPS calibration fudge time 1: format 0 .003134, format 2 .004034
*/
/*
* Interface definitions
*/
#define DEVICE "/dev/wwvb%d" /* device name and unit */
#define SPEED232 B9600 /* uart speed (9600 baud) */
#define PRECISION (-13) /* precision assumed (about 100 us) */
#define PPS_PRECISION (-13) /* precision assumed (about 100 us) */
#define REFID "WWVB" /* reference ID */
#define DESCRIPTION "Spectracom WWVB/GPS Receiver" /* WRU */
#define LENWWVB0 22 /* format 0 timecode length */
#define LENWWVB2 24 /* format 2 timecode length */
#define LENWWVB3 29 /* format 3 timecode length */
#define MONLIN 15 /* number of monitoring lines */
/*
* WWVB unit control structure
*/
struct wwvbunit {
#ifdef HAVE_PPSAPI
struct refclock_atom atom; /* PPSAPI structure */
int ppsapi_tried; /* attempt PPSAPI once */
int ppsapi_lit; /* time_pps_create() worked */
int tcount; /* timecode sample counter */
int pcount; /* PPS sample counter */
#endif /* HAVE_PPSAPI */
l_fp laststamp; /* last <CR> timestamp */
int prev_eol_cr; /* was last EOL <CR> (not <LF>)? */
u_char lasthour; /* last hour (for monitor) */
u_char linect; /* count ignored lines (for monitor */
};
/*
* Transfer vector
*/
struct refclock refclock_wwvb = {
wwvb_start, /* start up driver */
wwvb_shutdown, /* shut down driver */
wwvb_poll, /* transmit poll message */
WWVB_CONTROL, /* fudge set/change notification */
noentry, /* initialize driver (not used) */
noentry, /* not used (old wwvb_buginfo) */
wwvb_timer /* called once per second */
};
/*
* wwvb_start - open the devices and initialize data for processing
*/
static int
wwvb_start(
int unit,
struct peer *peer
)
{
register struct wwvbunit *up;
struct refclockproc *pp;
int fd;
char device[20];
/*
* Open serial port. Use CLK line discipline, if available.
*/
snprintf(device, sizeof(device), DEVICE, unit);
fd = refclock_open(&peer->srcadr, device, SPEED232, LDISC_CLK);
if (fd <= 0)
return (0);
/*
* Allocate and initialize unit structure
*/
up = emalloc_zero(sizeof(*up));
pp = peer->procptr;
pp->io.clock_recv = wwvb_receive;
pp->io.srcclock = peer;
pp->io.datalen = 0;
pp->io.fd = fd;
if (!io_addclock(&pp->io)) {
close(fd);
pp->io.fd = -1;
free(up);
return (0);
}
pp->unitptr = up;
/*
* wwvb_shutdown - shut down the clock
*/
static void
wwvb_shutdown(
int unit,
struct peer *peer
)
{
struct refclockproc * pp;
struct wwvbunit * up;
pp = peer->procptr;
up = pp->unitptr;
if (-1 != pp->io.fd)
io_closeclock(&pp->io);
if (NULL != up)
free(up);
}
/*
* wwvb_receive - receive data from the serial interface
*/
static void
wwvb_receive(
struct recvbuf *rbufp
)
{
struct wwvbunit *up;
struct refclockproc *pp;
struct peer *peer;
l_fp trtmp; /* arrival timestamp */
int tz; /* time zone */
int day, month; /* ddd conversion */
int temp; /* int temp */
char syncchar; /* synchronization indicator */
char qualchar; /* quality indicator */
char leapchar; /* leap indicator */
char dstchar; /* daylight/standard indicator */
char tmpchar; /* trashbin */
/*
* Initialize pointers and read the timecode and timestamp
*/
peer = rbufp->recv_peer;
pp = peer->procptr;
up = pp->unitptr;
temp = refclock_gtlin(rbufp, pp->a_lastcode, BMAX, &trtmp);
/*
* Note we get a buffer and timestamp for both a <cr> and <lf>,
* but only the <cr> timestamp is retained. Note: in format 0 on
* a Netclock/2 or upgraded 8170 the start bit is delayed 100
* +-50 us relative to the pps; however, on an unmodified 8170
* the start bit can be delayed up to 10 ms. In format 2 the
* reading precision is only to the millisecond. Thus, unless
* you have a PPS gadget and don't have to have the year, format
* 0 provides the lowest jitter.
* Save the timestamp of each <CR> in up->laststamp. Lines with
* no characters occur for every <LF>, and for some <CR>s when
* format 0 is used. Format 0 starts and ends each cycle with a
* <CR><LF> pair, format 2 starts each cycle with its only pair.
* The preceding <CR> is the on-time character for both formats.
* The timestamp provided with non-empty lines corresponds to
* the <CR> following the timecode, which is ultimately not used
* with format 0 and is used for the following timecode for
* format 2.
*/
if (temp == 0) {
if (up->prev_eol_cr) {
DPRINTF(2, ("wwvb: <LF> @ %s\n",
prettydate(&trtmp)));
} else {
up->laststamp = trtmp;
DPRINTF(2, ("wwvb: <CR> @ %s\n",
prettydate(&trtmp)));
}
up->prev_eol_cr = !up->prev_eol_cr;
return;
}
pp->lencode = temp;
pp->lastrec = up->laststamp;
up->laststamp = trtmp;
up->prev_eol_cr = TRUE;
DPRINTF(2, ("wwvb: code @ %s\n"
" using %s minus one char\n",
prettydate(&trtmp), prettydate(&pp->lastrec)));
if (L_ISZERO(&pp->lastrec))
return;
/*
* We get down to business, check the timecode format and decode
* its contents. This code uses the timecode length to determine
* format 0, 2 or 3. If the timecode has invalid length or is
* not in proper format, we declare bad format and exit.
*/
syncchar = qualchar = leapchar = dstchar = ' ';
tz = 0;
switch (pp->lencode) {
/*
* Timecode format 3: "0003I yyyymmdd hhmmss+0000SL#"
* WARNING: Undocumented, and the on-time character # is
* not yet handled correctly by this driver. It may be
* as simple as compensating for an additional 1/960 s.
*/
if (sscanf(pp->a_lastcode,
"0003%c %4d%2d%2d %2d%2d%2d+0000%c%c",
&syncchar, &pp->year, &month, &day, &pp->hour,
&pp->minute, &pp->second, &dstchar, &leapchar) == 8)
{
pp->day = ymd2yd(pp->year, month, day);
pp->nsec = 0;
break;
}
goto bad_format;
default:
bad_format:
/*
* Unknown format: If dumping internal table, record
* stats; otherwise, declare bad format.
*/
if (up->linect > 0) {
up->linect--;
record_clock_stats(&peer->srcadr,
pp->a_lastcode);
} else {
refclock_report(peer, CEVNT_BADREPLY);
}
return;
}
/*
* Decode synchronization, quality and leap characters. If
* unsynchronized, set the leap bits accordingly and exit.
* Otherwise, set the leap bits according to the leap character.
* Once synchronized, the dispersion depends only on the
* quality character.
*/
switch (qualchar) {
case ' ':
pp->disp = .001;
pp->lastref = pp->lastrec;
break;
/*
* Process the new sample in the median filter and determine the
* timecode timestamp, but only if the PPS is not in control.
*/
#ifdef HAVE_PPSAPI
up->tcount++;
if (peer->flags & FLAG_PPS)
return;
#endif /* HAVE_PPSAPI */
if (!refclock_process_f(pp, pp->fudgetime2))
refclock_report(peer, CEVNT_BADTIME);
}
/*
* wwvb_timer - called once per second by the transmit procedure
*/
static void
wwvb_timer(
int unit,
struct peer *peer
)
{
register struct wwvbunit *up;
struct refclockproc *pp;
char pollchar; /* character sent to clock */
#ifdef DEBUG
l_fp now;
#endif
/*
* Time to poll the clock. The Spectracom clock responds to a
* 'T' by returning a timecode in the format(s) specified above.
* Note there is no checking on state, since this may not be the
* only customer reading the clock. Only one customer need poll
* the clock; all others just listen in.
*/
pp = peer->procptr;
up = pp->unitptr;
if (up->linect > 0)
pollchar = 'R';
else
pollchar = 'T';
if (write(pp->io.fd, &pollchar, 1) != 1)
refclock_report(peer, CEVNT_FAULT);
#ifdef DEBUG
get_systime(&now);
if (debug)
printf("%c poll at %s\n", pollchar, prettydate(&now));
#endif
#ifdef HAVE_PPSAPI
if (up->ppsapi_lit &&
refclock_pps(peer, &up->atom, pp->sloppyclockflag) > 0) {
up->pcount++,
peer->flags |= FLAG_PPS;
peer->precision = PPS_PRECISION;
}
#endif /* HAVE_PPSAPI */
}
/*
* wwvb_poll - called by the transmit procedure
*/
static void
wwvb_poll(
int unit,
struct peer *peer
)
{
register struct wwvbunit *up;
struct refclockproc *pp;
/*
* Sweep up the samples received since the last poll. If none
* are received, declare a timeout and keep going.
*/
pp = peer->procptr;
up = pp->unitptr;
pp->polls++;
/*
* If the monitor flag is set (flag4), we dump the internal
* quality table at the first timecode beginning the day.
*/
if (pp->sloppyclockflag & CLK_FLAG4 && pp->hour <
(int)up->lasthour)
up->linect = MONLIN;
up->lasthour = (u_char)pp->hour;
/*
* Process median filter samples. If none received, declare a
* timeout and keep going.
*/
#ifdef HAVE_PPSAPI
if (up->pcount == 0) {
peer->flags &= ~FLAG_PPS;
peer->precision = PRECISION;
}
if (up->tcount == 0) {
pp->coderecv = pp->codeproc;
refclock_report(peer, CEVNT_TIMEOUT);
return;
}
up->pcount = up->tcount = 0;
#else /* HAVE_PPSAPI */
if (pp->coderecv == pp->codeproc) {
refclock_report(peer, CEVNT_TIMEOUT);
return;
}
#endif /* HAVE_PPSAPI */
refclock_receive(peer);
record_clock_stats(&peer->srcadr, pp->a_lastcode);
#ifdef DEBUG
if (debug)
printf("wwvb: timecode %d %s\n", pp->lencode,
pp->a_lastcode);
#endif
}
/*
* wwvb_control - fudge parameters have been set or changed
*/
#ifdef HAVE_PPSAPI
static void
wwvb_control(
int unit,
const struct refclockstat *in_st,
struct refclockstat *out_st,
struct peer *peer
)
{
register struct wwvbunit *up;
struct refclockproc *pp;
pp = peer->procptr;
up = pp->unitptr;
if (!(pp->sloppyclockflag & CLK_FLAG1)) {
if (!up->ppsapi_tried)
return;
up->ppsapi_tried = 0;
if (!up->ppsapi_lit)
return;
peer->flags &= ~FLAG_PPS;
peer->precision = PRECISION;
time_pps_destroy(up->atom.handle);
up->atom.handle = 0;
up->ppsapi_lit = 0;
return;
}
if (up->ppsapi_tried)
return;
/*
* Light up the PPSAPI interface.
*/
up->ppsapi_tried = 1;
if (refclock_ppsapi(pp->io.fd, &up->atom)) {
up->ppsapi_lit = 1;
return;
}
