/*
* This driver supports the Austron 2200A/2201A GPS Receiver with
* Buffered RS-232-C Interface Module. Note that the original 2200/2201
* receivers will not work reliably with this driver, since the older
* design cannot accept input commands at any reasonable data rate.
*
* The program sends a "*toc\r" to the radio and expects a response of
* the form "yy:ddd:hh:mm:ss.mmm\r" where yy = year of century, ddd =
* day of year, hh:mm:ss = second of day and mmm = millisecond of
* second. Then, it sends statistics commands to the radio and expects
* a multi-line reply showing the corresponding statistics or other
* selected data. Statistics commands are sent in order as determined by
* a vector of commands; these might have to be changed with different
* radio options. If flag4 of the fudge configuration command is set to
* 1, the statistics data are written to the clockstats file for later
* processing.
*
* In order for this code to work, the radio must be placed in non-
* interactive mode using the "off" command and with a single <cr>
* response using the "term cr" command. The setting of the "echo"
* and "df" commands does not matter. The radio should select UTC
* timescale using the "ts utc" command.
*
* There are two modes of operation for this driver. The first with
* default configuration is used with stock kernels and serial-line
* drivers and works with almost any machine. In this mode the driver
* assumes the radio captures a timestamp upon receipt of the "*" that
* begins the driver query. Accuracies in this mode are in the order of
* a millisecond or two and the receiver can be connected to only one
* host.
*
* The second mode of operation can be used for SunOS kernels that have
* been modified with the ppsclock streams module included in this
* distribution. The mode is enabled if flag3 of the fudge configuration
* command has been set to 1. In this mode a precise timestamp is
* available using a gadget box and 1-pps signal from the receiver. This
* improves the accuracy to the order of a few tens of microseconds. In
* addition, the serial output and 1-pps signal can be bussed to more
* than one hosts, but only one of them should be connected to the
* radio input data line.
*/
/*
* AS2201 unit control structure.
*/
struct as2201unit {
char *lastptr; /* statistics buffer pointer */
char stats[SMAX]; /* statistics buffer */
int linect; /* count of lines remaining */
int index; /* current statistics command */
};
/*
* Radio commands to extract statitistics
*
* A command consists of an ASCII string terminated by a <cr> (\r). The
* command list consist of a sequence of commands terminated by a null
* string ("\0"). One command from the list is sent immediately
* following each received timecode (*toc\r command) and the ASCII
* strings received from the radio are saved along with the timecode in
* the clockstats file. Subsequent commands are sent at each timecode,
* with the last one in the list followed by the first one. The data
* received from the radio consist of ASCII strings, each terminated by
* a <cr> (\r) character. The number of strings for each command is
* specified as the first line of output as an ASCII-encode number. Note
* that the ETF command requires the Input Buffer Module and the LORAN
* commands require the LORAN Assist Module. However, if these modules
* are not installed, the radio and this driver will continue to operate
* successfuly, but no data will be captured for these commands.
*/
static char stat_command[][30] = {
"ITF\r", /* internal time/frequency */
"ETF\r", /* external time/frequency */
"LORAN ENSEMBLE\r", /* GPS/LORAN ensemble statistics */
"LORAN TDATA\r", /* LORAN signal data */
"ID;OPT;VER\r", /* model; options; software version */
/*
* Transfer vector
*/
struct refclock refclock_as2201 = {
as2201_start, /* start up driver */
as2201_shutdown, /* shut down driver */
as2201_poll, /* transmit poll message */
noentry, /* not used (old as2201_control) */
noentry, /* initialize driver (not used) */
noentry, /* not used (old as2201_buginfo) */
NOFLAGS /* not used */
};
/*
* as2201_start - open the devices and initialize data for processing
*/
static int
as2201_start(
int unit,
struct peer *peer
)
{
register struct as2201unit *up;
struct refclockproc *pp;
int fd;
char gpsdev[20];
/*
* Open serial port. Use CLK line discipline, if available.
*/
snprintf(gpsdev, sizeof(gpsdev), DEVICE, unit);
fd = refclock_open(&peer->srcadr, gpsdev, 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 = as2201_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;
/*
* as2201_shutdown - shut down the clock
*/
static void
as2201_shutdown(
int unit,
struct peer *peer
)
{
register struct as2201unit *up;
struct refclockproc *pp;
pp = peer->procptr;
up = pp->unitptr;
if (-1 != pp->io.fd)
io_closeclock(&pp->io);
if (NULL != up)
free(up);
}
/*
* as2201__receive - receive data from the serial interface
*/
static void
as2201_receive(
struct recvbuf *rbufp
)
{
register struct as2201unit *up;
struct refclockproc *pp;
struct peer *peer;
l_fp trtmp;
size_t octets;
/*
* Initialize pointers and read the timecode and timestamp.
*/
peer = rbufp->recv_peer;
pp = peer->procptr;
up = pp->unitptr;
pp->lencode = refclock_gtlin(rbufp, pp->a_lastcode, BMAX, &trtmp);
#ifdef DEBUG
if (debug)
printf("gps: timecode %d %d %s\n",
up->linect, pp->lencode, pp->a_lastcode);
#endif
if (pp->lencode == 0)
return;
/*
* If linect is greater than zero, we must be in the middle of a
* statistics operation, so simply tack the received data at the
* end of the statistics string. If not, we could either have
* just received the timecode itself or a decimal number
* indicating the number of following lines of the statistics
* reply. In the former case, write the accumulated statistics
* data to the clockstats file and continue onward to process
* the timecode; in the later case, save the number of lines and
* quietly return.
*/
if (pp->sloppyclockflag & CLK_FLAG2)
pp->lastrec = trtmp;
if (up->linect > 0) {
up->linect--;
if ((int)(up->lastptr - up->stats + pp->lencode) > SMAX - 2)
return;
*up->lastptr++ = ' ';
memcpy(up->lastptr, pp->a_lastcode, 1 + pp->lencode);
up->lastptr += pp->lencode;
return;
} else {
if (pp->lencode == 1) {
up->linect = atoi(pp->a_lastcode);
return;
} else {
record_clock_stats(&peer->srcadr, up->stats);
#ifdef DEBUG
if (debug)
printf("gps: stat %s\n", up->stats);
#endif
}
}
up->lastptr = up->stats;
*up->lastptr = '\0';
/*
* We get down to business, check the timecode format and decode
* its contents. If the timecode has invalid length or is not in
* proper format, we declare bad format and exit.
*/
if (pp->lencode < LENTOC) {
refclock_report(peer, CEVNT_BADREPLY);
return;
}
/*
* Test for synchronization (this is a temporary crock).
*/
if (pp->a_lastcode[2] != ':')
pp->leap = LEAP_NOTINSYNC;
else
pp->leap = LEAP_NOWARNING;
/*
* Process the new sample in the median filter and determine the
* timecode timestamp.
*/
if (!refclock_process(pp)) {
refclock_report(peer, CEVNT_BADTIME);
return;
}
/*
* If CLK_FLAG4 is set, initialize the statistics buffer and
* send the next command. If not, simply write the timecode to
* the clockstats file.
*/
if ((int)(up->lastptr - up->stats + pp->lencode) > SMAX - 2)
return;
memcpy(up->lastptr, pp->a_lastcode, pp->lencode);
up->lastptr += pp->lencode;
if (pp->sloppyclockflag & CLK_FLAG4) {
octets = strlen(stat_command[up->index]);
if ((int)(up->lastptr - up->stats + 1 + octets) > SMAX - 2)
return;
*up->lastptr++ = ' ';
memcpy(up->lastptr, stat_command[up->index], octets);
up->lastptr += octets - 1;
*up->lastptr = '\0';
refclock_write(peer, stat_command[up->index],
strlen(stat_command[up->index]),
"command");
up->index++;
if (*stat_command[up->index] == '\0')
up->index = 0;
}
}
/*
* as2201_poll - called by the transmit procedure
*
* We go to great pains to avoid changing state here, since there may be
* more than one eavesdropper receiving the same timecode.
*/
static void
as2201_poll(
int unit,
struct peer *peer
)
{
struct refclockproc *pp;
/*
* Send a "\r*toc\r" to get things going. We go to great pains
* to avoid changing state, since there may be more than one
* eavesdropper watching the radio.
*/
pp = peer->procptr;
if (write(pp->io.fd, "\r*toc\r", 6) != 6) {
refclock_report(peer, CEVNT_FAULT);
} else {
pp->polls++;
if (!(pp->sloppyclockflag & CLK_FLAG2))
get_systime(&pp->lastrec);
}
if (pp->coderecv == pp->codeproc) {
refclock_report(peer, CEVNT_TIMEOUT);
return;
}
refclock_receive(peer);
}
