/* $NetBSD: refclock_ulink.c,v 1.6 2024/08/18 20:47:19 christos Exp $ */

/* $NetBSD: refclock_ulink.c,v 1.6 2024/08/18 20:47:19 christos Exp $ */

/*
* refclock_ulink - clock driver for Ultralink WWVB receiver
*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#if defined(REFCLOCK) && defined(CLOCK_ULINK)

#include <stdio.h>
#include <ctype.h>

#include "ntpd.h"
#include "ntp_io.h"
#include "ntp_refclock.h"
#include "ntp_stdlib.h"

/* This driver supports ultralink Model 320,325,330,331,332 WWVB radios
*
* this driver was based on the refclock_wwvb.c driver
* in the ntp distribution.
*
* Fudge Factors
*
* fudge flag1 0 don't poll clock
* 1 send poll character
*
* revision history:
* 99/9/09 j.c.lang original edit's
* 99/9/11 j.c.lang changed timecode parse to
* match what the radio actually
* sends.
* 99/10/11 j.c.lang added support for continous
* time code mode (dipsw2)
* 99/11/26 j.c.lang added support for 320 decoder
* (taken from Dave Strout's
* Model 320 driver)
* 99/11/29 j.c.lang added fudge flag 1 to control
* clock polling
* 99/12/15 j.c.lang fixed 320 quality flag
* 01/02/21 s.l.smith fixed 33x quality flag
* added more debugging stuff
* updated 33x time code explanation
* 04/01/23 frank migge added support for 325 decoder
* (tested with ULM325.F)
*
* Questions, bugs, ideas send to:
* Joseph C. Lang
* [email protected]
*
* Dave Strout
* [email protected]
*
* Frank Migge
* [email protected]
*
*
* on the Ultralink model 33X decoder Dip switch 2 controls
* polled or continous timecode
* set fudge flag1 if using polled (needed for model 320 and 325)
* dont set fudge flag1 if dip switch 2 is set on model 33x decoder
*/

/*
* Interface definitions
*/
#define DEVICE "/dev/wwvb%d" /* device name and unit */
#define SPEED232 B9600 /* uart speed (9600 baud) */
#define PRECISION (-10) /* precision assumed (about 10 ms) */
#define REFID "WWVB" /* reference ID */
#define DESCRIPTION "Ultralink WWVB Receiver" /* WRU */

#define LEN33X 32 /* timecode length Model 33X and 325 */
#define LEN320 24 /* timecode length Model 320 */

#define SIGLCHAR33x 'S' /* signal strength identifier char 325 */
#define SIGLCHAR325 'R' /* signal strength identifier char 33x */

/*
* unit control structure
*/
struct ulinkunit {
u_char tcswitch; /* timecode switch */
l_fp laststamp; /* last receive timestamp */
};

/*
* Function prototypes
*/
static int ulink_start (int, struct peer *);
static void ulink_shutdown (int, struct peer *);
static void ulink_receive (struct recvbuf *);
static void ulink_poll (int, struct peer *);

/*
* Transfer vector
*/
struct refclock refclock_ulink = {
ulink_start, /* start up driver */
ulink_shutdown, /* shut down driver */
ulink_poll, /* transmit poll message */
noentry, /* not used */
noentry, /* not used */
noentry, /* not used */
NOFLAGS
};

/*
* ulink_start - open the devices and initialize data for processing
*/
static int
ulink_start(
int unit,
struct peer *peer
)
{
register struct ulinkunit *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(sizeof(struct ulinkunit));
memset(up, 0, sizeof(struct ulinkunit));
pp = peer->procptr;
pp->io.clock_recv = ulink_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;

/*
* Initialize miscellaneous variables
*/
peer->precision = PRECISION;
pp->clockdesc = DESCRIPTION;
memcpy((char *)&pp->refid, REFID, 4);
return (1);
}

/*
* ulink_shutdown - shut down the clock
*/
static void
ulink_shutdown(
int unit,
struct peer *peer
)
{
register struct ulinkunit *up;
struct refclockproc *pp;

pp = peer->procptr;
up = pp->unitptr;
if (pp->io.fd != -1)
io_closeclock(&pp->io);
if (up != NULL)
free(up);
}

/*
* ulink_receive - receive data from the serial interface
*/
static void
ulink_receive(
struct recvbuf *rbufp
)
{
struct ulinkunit *up;
struct refclockproc *pp;
struct peer *peer;

l_fp trtmp; /* arrival timestamp */
int quality = INT_MAX; /* quality indicator */
int temp; /* int temp */
char syncchar; /* synchronization indicator */
char leapchar; /* leap indicator */
char modechar; /* model 320 mode flag */
char siglchar; /* model difference between 33x/325 */
char char_quality[2]; /* temp quality flag */

/*
* 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.
*/
if (temp == 0) {
if (up->tcswitch == 0) {
up->tcswitch = 1;
up->laststamp = trtmp;
} else
up->tcswitch = 0;
return;
}
pp->lencode = temp;
pp->lastrec = up->laststamp;
up->laststamp = trtmp;
up->tcswitch = 1;
#ifdef DEBUG
if (debug)
printf("ulink: timecode %d %s\n", pp->lencode,
pp->a_lastcode);
#endif

/*
* 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.
*/
syncchar = leapchar = modechar = siglchar = ' ';
switch (pp->lencode ) {
case LEN33X:

/*
* First we check if the format is 33x or 325:
* <CR><LF>S9+D 00 YYYY+DDDUTCS HH:MM:SSL+5 (33x)
* <CR><LF>R5_1C00LYYYY+DDDUTCS HH:MM:SSL+5 (325)
* simply by comparing if the signal level is 'S' or 'R'
*/

if (sscanf(pp->a_lastcode, "%c%*31c",
&siglchar) == 1) {

if(siglchar == SIGLCHAR325) {

/*
* decode for a Model 325 decoder.
* Timecode format from January 23, 2004 datasheet is:
*
* <CR><LF>R5_1C00LYYYY+DDDUTCS HH:MM:SSL+5
*
* R WWVB decodersignal readability R1 - R5
* 5 R1 is unreadable, R5 is best
* space a space (0x20)
* 1 Data bit 0, 1, M (pos mark), or ? (unknown).
* C Reception from either (C)olorado or (H)awaii
* 00 Hours since last good WWVB frame sync. Will
* be 00-99
* space Space char (0x20) or (0xa5) if locked to wwvb
* YYYY Current year, 2000-2099
* + Leap year indicator. '+' if a leap year,
* a space (0x20) if not.
* DDD Day of year, 000 - 365.
* UTC Timezone (always 'UTC').
* S Daylight savings indicator
* S - standard time (STD) in effect
* O - during STD to DST day 0000-2400
* D - daylight savings time (DST) in effect
* I - during DST to STD day 0000-2400
* space Space character (0x20)
* HH Hours 00-23
* : This is the REAL in sync indicator (: = insync)
* MM Minutes 00-59
* : : = in sync ? = NOT in sync
* SS Seconds 00-59
* L Leap second flag. Changes from space (0x20)
* to 'I' or 'D' during month preceding leap
* second adjustment. (I)nsert or (D)elete
* +5 UT1 correction (sign + digit ))
*/

if (sscanf(pp->a_lastcode,
"%*2c %*2c%2c%*c%4d%*c%3d%*4c %2d%c%2d:%2d%c%*2c",
char_quality, &pp->year, &pp->day,
&pp->hour, &syncchar, &pp->minute, &pp->second,
&leapchar) == 8) {

if (char_quality[0] == '0') {
quality = 0;
} else if (char_quality[0] == '0') {
quality = (char_quality[1] & 0x0f);
} else {
quality = 99;
}

if (leapchar == 'I' ) leapchar = '+';
if (leapchar == 'D' ) leapchar = '-';

/*
#ifdef DEBUG
if (debug) {
printf("ulink: char_quality %c %c\n",
char_quality[0], char_quality[1]);
printf("ulink: quality %d\n", quality);
printf("ulink: syncchar %x\n", syncchar);
printf("ulink: leapchar %x\n", leapchar);
}
#endif
*/

}

}
if(siglchar == SIGLCHAR33x) {

/*
* We got a Model 33X decoder.
* Timecode format from January 29, 2001 datasheet is:
* <CR><LF>S9+D 00 YYYY+DDDUTCS HH:MM:SSL+5
* S WWVB decoder sync indicator. S for in-sync(?)
* or N for noisy signal.
* 9+ RF signal level in S-units, 0-9 followed by
* a space (0x20). The space turns to '+' if the
* level is over 9.
* D Data bit 0, 1, 2 (position mark), or
* 3 (unknown).
* space Space character (0x20)
* 00 Hours since last good WWVB frame sync. Will
* be 00-23 hrs, or '1d' to '7d'. Will be 'Lk'
* if currently in sync.
* space Space character (0x20)
* YYYY Current year, 1990-2089
* + Leap year indicator. '+' if a leap year,
* a space (0x20) if not.
* DDD Day of year, 001 - 366.
* UTC Timezone (always 'UTC').
* S Daylight savings indicator
* S - standard time (STD) in effect
* O - during STD to DST day 0000-2400
* D - daylight savings time (DST) in effect
* I - during DST to STD day 0000-2400
* space Space character (0x20)
* HH Hours 00-23
* : This is the REAL in sync indicator (: = insync)
* MM Minutes 00-59
* : : = in sync ? = NOT in sync
* SS Seconds 00-59
* L Leap second flag. Changes from space (0x20)
* to '+' or '-' during month preceding leap
* second adjustment.
* +5 UT1 correction (sign + digit ))
*/

if (sscanf(pp->a_lastcode,
"%*4c %2c %4d%*c%3d%*4c %2d%c%2d:%2d%c%*2c",
char_quality, &pp->year, &pp->day,
&pp->hour, &syncchar, &pp->minute, &pp->second,
&leapchar) == 8) {

if (char_quality[0] == 'L') {
quality = 0;
} else if (char_quality[0] == '0') {
quality = (char_quality[1] & 0x0f);
} else {
quality = 99;
}

/*
#ifdef DEBUG
if (debug) {
printf("ulink: char_quality %c %c\n",
char_quality[0], char_quality[1]);
printf("ulink: quality %d\n", quality);
printf("ulink: syncchar %x\n", syncchar);
printf("ulink: leapchar %x\n", leapchar);
}
#endif
*/

}
}
break;
}
/*FALLTHROUGH*/

case LEN320:

/*
* Model 320 Decoder
* The timecode format is:
*
* <cr><lf>SQRYYYYDDD+HH:MM:SS.mmLT<cr>
*
* where:
*
* S = 'S' -- sync'd in last hour,
* '0'-'9' - hours x 10 since last update,
* '?' -- not in sync
* Q = Number of correlating time-frames, from 0 to 5
* R = 'R' -- reception in progress,
* 'N' -- Noisy reception,
* ' ' -- standby mode
* YYYY = year from 1990 to 2089
* DDD = current day from 1 to 366
* + = '+' if current year is a leap year, else ' '
* HH = UTC hour 0 to 23
* MM = Minutes of current hour from 0 to 59
* SS = Seconds of current minute from 0 to 59
* mm = 10's milliseconds of the current second from 00 to 99
* L = Leap second pending at end of month
* 'I' = insert, 'D'= delete
* T = DST <-> STD transition indicators
*
*/

if (sscanf(pp->a_lastcode, "%c%1d%c%4d%3d%*c%2d:%2d:%2d.%2ld%c",
&syncchar, &quality, &modechar, &pp->year, &pp->day,
&pp->hour, &pp->minute, &pp->second,
&pp->nsec, &leapchar) == 10) {
pp->nsec *= 10000000; /* M320 returns 10's of msecs */
if (leapchar == 'I' ) leapchar = '+';
if (leapchar == 'D' ) leapchar = '-';
if (syncchar != '?' ) syncchar = ':';
break;
}
/*FALLTHROUGH*/
default:
refclock_report(peer, CEVNT_BADREPLY);
return;
}

/*
* Decode quality indicator
* For the 325 & 33x series, the lower the number the "better"
* the time is. I used the dispersion as the measure of time
* quality. The quality indicator in the 320 is the number of
* correlating time frames (the more the better)
*/

/*
* The spec sheet for the 325 & 33x series states the clock will
* maintain +/-0.002 seconds accuracy when locked to WWVB. This
* is indicated by 'Lk' in the quality portion of the incoming
* string. When not in lock, a drift of +/-0.015 seconds should
* be allowed for.
* With the quality indicator decoding scheme above, the 'Lk'
* condition will produce a quality value of 0. If the quality
* indicator starts with '0' then the second character is the
* number of hours since we were last locked. If the first
* character is anything other than 'L' or '0' then we have been
* out of lock for more than 9 hours so we assume the worst and
* force a quality value that selects the 'default' maximum
* dispersion. The dispersion values below are what came with the
* driver. They're not unreasonable so they've not been changed.
*/

if (pp->lencode == LEN33X) {
switch (quality) {
case 0 :
pp->disp=.002;
break;
case 1 :
pp->disp=.02;
break;
case 2 :
pp->disp=.04;
break;
case 3 :
pp->disp=.08;
break;
default:
pp->disp=MAXDISPERSE;
break;
}
} else {
switch (quality) {
case 5 :
pp->disp=.002;
break;
case 4 :
pp->disp=.02;
break;
case 3 :
pp->disp=.04;
break;
case 2 :
pp->disp=.08;
break;
case 1 :
pp->disp=.16;
break;
default:
pp->disp=MAXDISPERSE;
break;
}

}

/*
* Decode synchronization, and leap characters. If
* unsynchronized, set the leap bits accordingly and exit.
* Otherwise, set the leap bits according to the leap character.
*/

if (syncchar != ':')
pp->leap = LEAP_NOTINSYNC;
else if (leapchar == '+')
pp->leap = LEAP_ADDSECOND;
else if (leapchar == '-')
pp->leap = LEAP_DELSECOND;
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);
}

}

/*
* ulink_poll - called by the transmit procedure
*/

static void
ulink_poll(
int unit,
struct peer *peer
)
{
struct refclockproc *pp;
char pollchar;

pp = peer->procptr;
pollchar = 'T';
if (pp->sloppyclockflag & CLK_FLAG1) {
if (write(pp->io.fd, &pollchar, 1) != 1)
refclock_report(peer, CEVNT_FAULT);
else
pp->polls++;
}
else
pp->polls++;

if (pp->coderecv == pp->codeproc) {
refclock_report(peer, CEVNT_TIMEOUT);
return;
}
pp->lastref = pp->lastrec;
refclock_receive(peer);
record_clock_stats(&peer->srcadr, pp->a_lastcode);

}

#else
NONEMPTY_TRANSLATION_UNIT
#endif /* REFCLOCK */