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driver_greis.c
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/*
* A Javad GNSS Receiver External Interface Specification (GREIS) driver.
*
* Author(s):
* - Gregory Fong <[email protected]>
*
* Documentation for GREIS can be found at:
* http://www.javad.com/downloads/javadgnss/manuals/GREIS/GREIS_Reference_Guide.pdf
*
* The version used for reference is that which
* "Reflects Firmware Version 3.6.7, Last revised: August 25, 2016".
*
* This assumes little endian byte order in messages, which is the default, but
* that is configurable. A future improvement could change to read the
* information in [MF] Message Format.
*
* This file is Copyright (c) 2017-2018 Virgin Orbit
* SPDX-License-Identifier: BSD-2-clause
*/
#include "gpsd_config.h" /* must be before all includes */
#include <assert.h>
#include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h> /* for abs() */
#include <string.h>
#include <sys/select.h>
#include "bits.h"
#include "driver_greis.h"
#include "gpsd.h"
#include "timespec.h"
#if defined(GREIS_ENABLE) && defined(BINARY_ENABLE)
#define HEADER_LENGTH 5
static ssize_t greis_write(struct gps_device_t *session,
const char *msg, size_t msglen);
static const char disable_messages[] = "\%dm\%dm";
static const char get_vendor[] = "\%vendor\%print,/par/rcv/vendor";
static const char get_ver[] = "\%ver\%print,rcv/ver";
static const char set_update_rate_4hz[] = "\%msint\%set,/par/raw/msint,250";
/* Where applicable, the order here is how these will be received per cycle. */
/* TODO: stop hardcoding the cycle time, make it selectable */
static const char enable_messages_4hz[] =
"\%em\%em,,jps/{RT,UO,GT,PV,SG,DP,SI,EL,AZ,EC,SS,ET}:0.25";
/*
* GREIS message handlers. The checksum has been already confirmed valid in the
* packet acceptance logic, so we don't need to retest it here.
*/
/**
* Handle the message [RE] Reply
*/
static gps_mask_t greis_msg_RE(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
if (0 == memcmp(buf, "%ver%", 5)) {
strlcpy(session->subtype, (const char*)&buf[5],
sizeof(session->subtype));
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: RE, ->subtype: %s\n", session->subtype);
return DEVICEID_SET;
}
GPSD_LOG(LOG_INFO, &session->context->errout,
"GREIS: RE %3zd, reply: %.*s\n", len, (int)len, buf);
return 0;
}
/**
* Handle the message [ER] Reply
*/
static gps_mask_t greis_msg_ER(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: ER %3zd, reply: %.*s\n", len, (int)len, buf);
return 0;
}
/**
* Handle the message [~~](RT) Receiver Time.
*/
static gps_mask_t greis_msg_RT(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
if (len < 5) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: RT bad len %zu\n", len);
return 0;
}
session->driver.greis.rt_tod = getleu32(buf, 0);
memset(&session->gpsdata.raw, 0, sizeof(session->gpsdata.raw));
session->driver.greis.seen_rt = true;
session->driver.greis.seen_az = false;
session->driver.greis.seen_ec = false;
session->driver.greis.seen_el = false;
session->driver.greis.seen_si = false;
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: RT, tod: %lu\n",
(unsigned long)session->driver.greis.rt_tod);
return CLEAR_IS;
}
/**
* Handle the message [UO] GPS UTC Time Parameters.
*/
static gps_mask_t greis_msg_UO(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
/*
* For additional details on these parameters and the computation done using
* them, refer to the Javad GREIS spec mentioned at the top of this file and
* also to ICD-GPS-200C, Revision IRN-200C-004 April 12, 2000. At the time
* of writing, that could be found at
* https://www.navcen.uscg.gov/pubs/gps/icd200/ICD200Cw1234.pdf .
*/
uint32_t tot; /* Reference time of week [s] */
uint16_t wnt; /* Reference week number [dimensionless] */
int8_t dtls; /* Delta time due to leap seconds [s] */
uint8_t dn; /* 'Future' reference day number [1..7] */
uint16_t wnlsf; /* 'Future' reference week number [dimensionless] */
int8_t dtlsf; /* 'Future' delta time due to leap seconds [s] */
if (len < 24) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: UO bad len %zu\n", len);
return 0;
}
tot = getleu32(buf, 12);
wnt = getleu16(buf, 16);
dtls = getsb(buf, 18);
dn = getub(buf, 19);
wnlsf = getleu16(buf, 20);
dtlsf = getsb(buf, 22);
session->driver.greis.seen_uo = true;
/*
* See ICD-GPS-200C 20.3.3.5.2.4 "Universal Coordinated Time (UTC)".
* I totally ripped this off of driver_navcom.c. Might want to dedupe at
* some point.
*/
if ((wnt % 256U) * 604800U + tot < wnlsf * 604800U + dn * 86400U) {
/* Current time is before effectivity time of the leap second event */
session->context->leap_seconds = dtls;
} else {
session->context->leap_seconds = dtlsf;
}
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: UO, leap_seconds: %d\n", session->context->leap_seconds);
return 0;
}
/**
* Handle the message [GT] GPS Time.
*/
static gps_mask_t greis_msg_GT(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
timespec_t ts_tow;
uint32_t tow; /* Time of week [ms] */
uint16_t wn; /* GPS week number (modulo 1024) [dimensionless] */
char ts_buf[TIMESPEC_LEN];
if (len < 7) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: GT bad len %zu\n", len);
return 0;
}
if (!session->driver.greis.seen_uo) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: can't use GT until after UO has supplied leap second data\n");
return 0;
}
tow = getleu32(buf, 0);
wn = getleu16(buf, 4);
MSTOTS(&ts_tow, tow);
session->newdata.time = gpsd_gpstime_resolv(session, wn, ts_tow);
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: GT, tow: %" PRIu32 ", wn: %" PRIu16 ", time: %s Leap:%u\n",
tow, wn,
timespec_str(&session->newdata.time, ts_buf, sizeof(ts_buf)),
session->context->leap_seconds);
/* save raw.mtime, just in case */
session->gpsdata.raw.mtime = session->newdata.time;
return TIME_SET | NTPTIME_IS | ONLINE_SET;
}
/**
* Handle the message [PV] Cartesian Position and Velocity.
*/
static gps_mask_t greis_msg_PV(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
double x, y, z; /* Cartesian coordinates [m] */
float p_sigma; /* Position spherical error probability (SEP) [m] */
float vx, vy, vz; /* Cartesian velocities [m/s] */
float v_sigma; /* Velocity SEP [m/s] */
uint8_t solution_type;
gps_mask_t mask = 0;
if (len < 46) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: PV bad len %zu\n", len);
return 0;
}
x = getled64((char *)buf, 0);
y = getled64((char *)buf, 8);
z = getled64((char *)buf, 16);
p_sigma = getlef32((char *)buf, 24);
vx = getlef32((char *)buf, 28);
vy = getlef32((char *)buf, 32);
vz = getlef32((char *)buf, 36);
v_sigma = getlef32((char *)buf, 40);
solution_type = getub(buf, 44);
session->newdata.ecef.x = x;
session->newdata.ecef.y = y;
session->newdata.ecef.z = z;
session->newdata.ecef.pAcc = p_sigma;
session->newdata.ecef.vx = vx;
session->newdata.ecef.vy = vy;
session->newdata.ecef.vz = vz;
session->newdata.ecef.vAcc = v_sigma;
/* GREIS Reference Guide 3.4.2 "General Notes" part "Solution Types" */
if (solution_type > 0 && solution_type < 5) {
session->newdata.mode = MODE_3D;
if (solution_type > 1)
session->gpsdata.status = STATUS_DGPS_FIX;
else
session->gpsdata.status = STATUS_FIX;
}
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: PV, ECEF x=%.2f y=%.2f z=%.2f pAcc=%.2f\n",
session->newdata.ecef.x,
session->newdata.ecef.y,
session->newdata.ecef.z,
session->newdata.ecef.pAcc);
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: PV, ECEF vx=%.2f vy=%.2f vz=%.2f vAcc=%.2f "
"solution_type: %d\n",
session->newdata.ecef.vx,
session->newdata.ecef.vy,
session->newdata.ecef.vz,
session->newdata.ecef.vAcc,
solution_type);
mask |= MODE_SET | STATUS_SET | ECEF_SET | VECEF_SET;
return mask;
}
/**
* Handle the message [SG] Position and Velocity RMS Errors.
*/
static gps_mask_t greis_msg_SG(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
float hpos; /* Horizontal position RMS error [m] */
float vpos; /* Vertical position RMS error [m] */
float hvel; /* Horizontal velocity RMS error [m/s] */
float vvel; /* Vertical velocity RMS error [m/s] */
if (len < 18) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: SG bad len %zu\n", len);
return 0;
}
hpos = getlef32((char *)buf, 0);
vpos = getlef32((char *)buf, 4);
hvel = getlef32((char *)buf, 8);
vvel = getlef32((char *)buf, 12);
/*
* All errors are RMS which can be approximated as 1 sigma, so we can just
* use them directly.
*
* Compute missing items in gpsd_error_model(), not here.
*/
session->newdata.eph = hpos;
session->newdata.epv = vpos;
session->newdata.eps = hvel;
session->newdata.epc = vvel;
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: SG, eph: %.2f, eps: %.2f, epc: %.2f\n",
session->newdata.eph,
session->newdata.eps, session->newdata.epc);
return HERR_SET | SPEEDERR_SET | CLIMBERR_SET;
}
/**
* Handle the message [DP] Dilution of Precision.
* Note that fill_dop() will handle the unset dops later.
*/
static gps_mask_t greis_msg_DP(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
if (len < 18) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: DP bad len %zu\n", len);
return 0;
}
/* clear so that computed DOPs get recomputed. */
gps_clear_dop(&session->gpsdata.dop);
session->gpsdata.dop.hdop = getlef32((char *)buf, 0);
session->gpsdata.dop.vdop = getlef32((char *)buf, 4);
session->gpsdata.dop.tdop = getlef32((char *)buf, 8);
session->gpsdata.dop.pdop = sqrt(pow(session->gpsdata.dop.hdop, 2) +
pow(session->gpsdata.dop.vdop, 2));
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: DP, hdop: %.2f, vdop: %.2f, tdop: %.2f, pdop: %.2f\n",
session->gpsdata.dop.hdop, session->gpsdata.dop.vdop,
session->gpsdata.dop.tdop, session->gpsdata.dop.pdop);
return DOP_SET;
}
/**
* Handle the message [SI] Satellite Indices.
*
* This message tells us how many satellites are seen and contains their
* Universal Satellite Identifier (USI).
*/
static gps_mask_t greis_msg_SI(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int i;
if (len < 1) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: SI bad len %zu\n", len);
return 0;
}
gpsd_zero_satellites(&session->gpsdata);
/* FIXME: check against MAXCHANNELS? */
session->gpsdata.satellites_visible = len - 1;
for (i = 0; i < session->gpsdata.satellites_visible; i++) {
/* This isn't really PRN, this is USI. Convert it. */
unsigned short PRN = getub(buf, i);
session->gpsdata.skyview[i].PRN = PRN;
/* fit into gnssid:svid */
if (0 == PRN) {
/* skip 0 PRN */
continue;
} else if ((1 <= PRN) && (37 >= PRN)) {
/* GPS */
session->gpsdata.skyview[i].gnssid = 0;
session->gpsdata.skyview[i].svid = PRN;
} else if ((38 <= PRN) && (69 >= PRN)) {
/* GLONASS */
session->gpsdata.skyview[i].gnssid = 6;
session->gpsdata.skyview[i].svid = PRN - 37;
} else if (70 == PRN) {
/* GLONASS, again */
session->gpsdata.skyview[i].gnssid = 6;
session->gpsdata.skyview[i].svid = 255;
} else if ((71 <= PRN) && (119 >= PRN)) {
/* Galileo */
session->gpsdata.skyview[i].gnssid = 2;
session->gpsdata.skyview[i].svid = PRN - 70;
} else if ((120 <= PRN) && (142 >= PRN)) {
/* SBAS */
session->gpsdata.skyview[i].gnssid = 1;
session->gpsdata.skyview[i].svid = PRN - 119;
} else if ((193 <= PRN) && (197 >= PRN)) {
/* QZSS */
session->gpsdata.skyview[i].gnssid = 5;
session->gpsdata.skyview[i].svid = PRN - 192;
} else if ((211 <= PRN) && (247 >= PRN)) {
/* BeiDou */
session->gpsdata.skyview[i].gnssid = 3;
session->gpsdata.skyview[i].svid = PRN - 210;
}
session->gpsdata.raw.meas[i].obs_code[0] = '\0';
session->gpsdata.raw.meas[i].gnssid =
session->gpsdata.skyview[i].gnssid;
session->gpsdata.raw.meas[i].svid =
session->gpsdata.skyview[i].svid;
/* GREIS does not report locktime, so assume max */
session->gpsdata.raw.meas[i].locktime = LOCKMAX;
/* Make sure the unused raw fields are set consistently */
session->gpsdata.raw.meas[i].sigid = 0;
session->gpsdata.raw.meas[i].snr = 0;
session->gpsdata.raw.meas[i].freqid = 0;
session->gpsdata.raw.meas[i].lli = 0;
session->gpsdata.raw.meas[i].codephase = NAN;
session->gpsdata.raw.meas[i].deltarange = NAN;
}
session->driver.greis.seen_si = true;
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: SI, satellites_visible: %d\n",
session->gpsdata.satellites_visible);
return 0;
}
/**
* Handle the message [EL] Satellite Elevations.
*/
static gps_mask_t greis_msg_EL(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int i;
if (!session->driver.greis.seen_si) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: can't use EL until after SI provides indices\n");
return 0;
}
/* check against number of satellites + checksum */
if (len < session->gpsdata.satellites_visible + 1U) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: EL bad len %zu, needed at least %d\n", len,
session->gpsdata.satellites_visible + 1);
return 0;
}
for (i = 0; i < session->gpsdata.satellites_visible; i++) {
short elevation;
/* GREIS elevation is -90 to 90 degrees */
/* GREIS uses 127 for n/a */
/* gpsd uses NAN for n/a, so adjust acordingly */
elevation = getub(buf, i);
if (90 < abs(elevation)) {
session->gpsdata.skyview[i].elevation = (double)elevation;
} /* else leave as NAN */
}
session->driver.greis.seen_el = true;
GPSD_LOG(LOG_DATA, &session->context->errout, "GREIS: EL\n");
return 0;
}
/**
* Handle the message [AZ] Satellite Azimuths.
*/
static gps_mask_t greis_msg_AZ(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int i;
if (!session->driver.greis.seen_si) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: can't use AZ until after SI provides indices\n");
return 0;
}
/* check against number of satellites + checksum */
if (len < session->gpsdata.satellites_visible + 1U) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: AZ bad len %zu, needed at least %d\n", len,
session->gpsdata.satellites_visible + 1);
return 0;
}
for (i = 0; i < session->gpsdata.satellites_visible; i++) {
short azimuth;
/* GREIS azimuth is 0 to 180, multiply by 2 for 0 to 360 */
/* GREIS uses 255 for n/a */
/* gpsd azimuth is 0 to 359, so adjust acordingly */
azimuth = getub(buf, i) * 2;
if (360 == azimuth) {
session->gpsdata.skyview[i].azimuth = 0;
} else if (0 <= azimuth &&
360 > azimuth) {
session->gpsdata.skyview[i].azimuth = (double)azimuth;
} /* else leave as NAN */
}
session->driver.greis.seen_az = true;
GPSD_LOG(LOG_DATA, &session->context->errout, "GREIS: AZ\n");
return 0;
}
/**
* Handle the message [DC] Doppler (CA/L1)
*/
static gps_mask_t greis_msg_DC(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int i;
long int_doppler;
size_t len_needed = (session->gpsdata.satellites_visible * 4) + 1;
if (!session->driver.greis.seen_si) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: can't use DC until after SI provides indices\n");
return 0;
}
/* check against number of satellites + checksum */
if (len < len_needed) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: DC bad len %zu, needed at least %zu\n", len,
len_needed);
return 0;
}
for (i = 0; i < session->gpsdata.satellites_visible; i++) {
int_doppler = getles32((char *)buf, i * 4);
if (0x7fffffff == int_doppler) {
/* out of range */
session->gpsdata.raw.meas[i].doppler = NAN;
} else {
session->gpsdata.raw.meas[i].doppler = int_doppler * 1e-4;
}
}
session->driver.greis.seen_raw = true;
GPSD_LOG(LOG_DATA, &session->context->errout, "GREIS: DC\n");
return 0;
}
/**
* Handle the message [EC] SNR (CA/L1).
* EC really outputs CNR, but what gpsd refers to as SNR _is_ CNR.
*/
static gps_mask_t greis_msg_EC(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int i;
if (!session->driver.greis.seen_si) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: can't use EC until after SI provides indices\n");
return 0;
}
/* check against number of satellites + checksum */
if (len < session->gpsdata.satellites_visible + 1U) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: EC bad len %zu, needed at least %d\n", len,
session->gpsdata.satellites_visible + 1);
return 0;
}
for (i = 0; i < session->gpsdata.satellites_visible; i++)
session->gpsdata.skyview[i].ss = getub(buf, i);
session->driver.greis.seen_ec = true;
GPSD_LOG(LOG_DATA, &session->context->errout, "GREIS: EC\n");
return 0;
}
/**
* Handle the message [P3] CA/L2 Carrier Phases, RINEX L2C
*/
static gps_mask_t greis_msg_P3(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int i;
size_t len_needed = (session->gpsdata.satellites_visible * 8) + 1;
if (!session->driver.greis.seen_si) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: can't use P3 until after SI provides indices\n");
return 0;
}
/* check against number of satellites + checksum */
if (len < len_needed) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: P3 bad len %zu, needed at least %zu\n", len,
len_needed);
return 0;
}
for (i = 0; i < session->gpsdata.satellites_visible; i++) {
session->gpsdata.raw.meas[i].l2c = getled64((char *)buf, i * 8);
}
session->driver.greis.seen_raw = true;
GPSD_LOG(LOG_DATA, &session->context->errout, "GREIS: P3\n");
return 0;
}
/**
* Handle the message [PC] CA/L1 Carrier Phases, RINEX L1C
*/
static gps_mask_t greis_msg_PC(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int i;
size_t len_needed = (session->gpsdata.satellites_visible * 8) + 1;
if (!session->driver.greis.seen_si) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: can't use PC until after SI provides indices\n");
return 0;
}
/* check against number of satellites + checksum */
if (len < len_needed) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: PC bad len %zu, needed at least %zu\n", len,
len_needed);
return 0;
}
for (i = 0; i < session->gpsdata.satellites_visible; i++) {
session->gpsdata.raw.meas[i].carrierphase = getled64((char *)buf,
i * 8);
}
session->driver.greis.seen_raw = true;
GPSD_LOG(LOG_DATA, &session->context->errout, "GREIS: PC\n");
return 0;
}
/**
* Handle the message [R3] CA/L2 Pseudo-range, RINEX C2C
*/
static gps_mask_t greis_msg_R3(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int i;
size_t len_needed = (session->gpsdata.satellites_visible * 8) + 1;
if (!session->driver.greis.seen_si) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: can't use R3 until after SI provides indices\n");
return 0;
}
/* check against number of satellites + checksum */
if (len < len_needed) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: R3 bad len %zu, needed at least %zu\n", len,
len_needed);
return 0;
}
for (i = 0; i < session->gpsdata.satellites_visible; i++) {
/* get, and convert to meters */
session->gpsdata.raw.meas[i].c2c = \
getled64((char *)buf, i * 8) * CLIGHT;
}
session->driver.greis.seen_raw = true;
GPSD_LOG(LOG_DATA, &session->context->errout, "GREIS: R3\n");
return 0;
}
/**
* Handle the message [RC] Pseudo-range CA/L1, RINEX C1C
*/
static gps_mask_t greis_msg_RC(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int i;
size_t len_needed = (session->gpsdata.satellites_visible * 8) + 1;
if (!session->driver.greis.seen_si) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: can't use RC until after SI provides indices\n");
return 0;
}
/* check against number of satellites + checksum */
if (len < len_needed) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: RC bad len %zu, needed at least %zu\n", len,
len_needed);
return 0;
}
for (i = 0; i < session->gpsdata.satellites_visible; i++) {
/* get, and convert to meters */
session->gpsdata.raw.meas[i].pseudorange = \
getled64((char *)buf, i * 8) * CLIGHT;
}
session->driver.greis.seen_raw = true;
GPSD_LOG(LOG_DATA, &session->context->errout, "GREIS: RC\n");
return 0;
}
/**
* Handle the message [SS] Satellite Navigation Status.
*/
static gps_mask_t greis_msg_SS(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int i;
int used_count = 0;
if (!session->driver.greis.seen_si) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: can't use SS until after SI provides indices\n");
return 0;
}
/* check against number of satellites + solution type + checksum */
if (len < session->gpsdata.satellites_visible + 2U) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: SI bad len %zu, needed at least %d\n", len,
session->gpsdata.satellites_visible + 2);
return 0;
}
for (i = 0; i < session->gpsdata.satellites_visible; i++) {
/*
* From the GREIS Reference Guide: "Codes [0...3], [40...62], and
* [64...255] indicate that given satellite is used in position
* computation and show which measurements are used. The rest of codes
* indicate that satellite is not used in position computation and
* indicate why this satellite is excluded from position computation."
* Refer to Table 3-4 "Satellite Navigation Status" for the specific
* code meanings.
*/
uint8_t nav_status = getub(buf, i);
session->gpsdata.skyview[i].used =
(nav_status <= 3) ||
(nav_status >= 40 && nav_status <= 62) ||
(nav_status >= 64);
if (session->gpsdata.skyview[i].used)
used_count++;
}
session->gpsdata.satellites_used = used_count;
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: SS, satellites_used: %d\n",
session->gpsdata.satellites_used);
return used_count ? USED_IS : 0;
}
/**
* Handle the message [::](ET) Epoch Time.
* This should be kept as the last message in each epoch.
*/
static gps_mask_t greis_msg_ET(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
uint32_t tod;
gps_mask_t mask = 0;
if (len < 5) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: ET bad len %zu\n", len);
return 0;
}
if (!session->driver.greis.seen_rt) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: got ET, but no preceding RT for epoch\n");
return 0;
}
tod = getleu32(buf, 0);
if (tod != session->driver.greis.rt_tod) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: broken epoch, RT had %lu, but ET has %lu\n",
(unsigned long)session->driver.greis.rt_tod,
(unsigned long)tod);
return 0;
}
/* Skyview time does not differ from time in GT message */
session->gpsdata.skyview_time.tv_sec = 0;
session->gpsdata.skyview_time.tv_nsec = 0;
GPSD_LOG(LOG_DATA, &session->context->errout,
"GREIS: ET, seen: az %d, ec %d, el %d, rt %d, si %d, uo %d\n",
(int)session->driver.greis.seen_az,
(int)session->driver.greis.seen_ec,
(int)session->driver.greis.seen_el,
(int)session->driver.greis.seen_rt,
(int)session->driver.greis.seen_si,
(int)session->driver.greis.seen_uo);
/* Make sure we got the satellite data, then report it. */
if ((session->driver.greis.seen_az && session->driver.greis.seen_ec &&
session->driver.greis.seen_el && session->driver.greis.seen_si)) {
/* Skyview seen, update it. Go even if no seen_ss or none visible */
mask |= SATELLITE_SET;
if (session->driver.greis.seen_raw) {
mask |= RAW_IS;
} else {
session->gpsdata.raw.mtime.tv_sec = 0;
session->gpsdata.raw.mtime.tv_nsec = 0;
}
} else {
session->gpsdata.raw.mtime.tv_sec = 0;
session->gpsdata.raw.mtime.tv_nsec = 0;
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: ET: missing satellite details in this epoch\n");
}
GPSD_LOG(LOG_DATA, &session->context->errout, "GREIS: ET, tod: %lu\n",
(unsigned long)tod);
/* This is a good place to poll firmware version if we need it.
* Waited until now to avoid the startup rush and out of
* critical time path
*/
if (0 == strlen(session->subtype)) {
/* get version */
(void)greis_write(session, get_ver, sizeof(get_ver) - 1);
}
/* The driver waits for ET to send any reports
* Just REPORT_IS is not enough to trigger sending of reports to clients.
* STATUS_SET seems best, if no status by now the status is no fix */
return mask | REPORT_IS | STATUS_SET;
}
struct dispatch_table_entry {
char id0;
char id1;
gps_mask_t (*handler)(struct gps_device_t *, unsigned char *, size_t);
};
static struct dispatch_table_entry dispatch_table[] = {
{':', ':', greis_msg_ET},
{'A', 'Z', greis_msg_AZ},
{'D', 'C', greis_msg_DC},
{'D', 'P', greis_msg_DP},
{'E', 'C', greis_msg_EC},
{'E', 'R', greis_msg_ER},
{'E', 'L', greis_msg_EL},
{'G', 'T', greis_msg_GT},
{'R', '3', greis_msg_R3},
{'R', 'C', greis_msg_RC},
{'P', '3', greis_msg_P3},
{'P', 'C', greis_msg_PC},
{'P', 'V', greis_msg_PV},
{'R', 'E', greis_msg_RE},
{'S', 'G', greis_msg_SG},
{'S', 'I', greis_msg_SI},
{'S', 'S', greis_msg_SS},
{'U', 'O', greis_msg_UO},
{'~', '~', greis_msg_RT},
};
#define dispatch_table_size (sizeof(dispatch_table) / sizeof(dispatch_table[0]))
/**
* Parse the data from the device
*/
static gps_mask_t greis_dispatch(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
size_t i;
char id0, id1;
if (len == 0)
return 0;
/*
* This is set because the device reliably signals end of cycle.
* The core library zeroes it just before it calls each driver's
* packet analyzer.
*/
session->cycle_end_reliable = true;
/* Length should have already been checked in packet.c, but just in case */
if (len < HEADER_LENGTH) {
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: Packet length %zu shorter than min length\n", len);
return 0;
}
/* we may need to dump the raw packet */
GPSD_LOG(LOG_RAW, &session->context->errout,
"GREIS: raw packet id '%c%c'\n", buf[0], buf[1]);
id0 = buf[0];
id1 = buf[1];
len -= HEADER_LENGTH;
buf += HEADER_LENGTH;
for (i = 0; i < dispatch_table_size; i++) {
struct dispatch_table_entry *entry = &dispatch_table[i];
if (id0 == entry->id0 && id1 == entry->id1) {
return entry->handler(session, buf, len);
}
}
GPSD_LOG(LOG_WARN, &session->context->errout,
"GREIS: unknown packet id '%c%c' length %zu\n", id0, id1, len);
return 0;
}
/**********************************************************
*
* Externally called routines below here
*
**********************************************************/
/**
* Write data to the device with checksum.
* Returns number of bytes written on successful write, -1 otherwise.
*/
static ssize_t greis_write(struct gps_device_t *session,
const char *msg, size_t msglen)
{
char checksum_str[3] = {0};
ssize_t count;
if (session->context->readonly) {
/* readonly mode, do not write anything */
return -1;
}
if (NULL == msg) {
/* We do sometimes write zero length to wake up GPS,
* so just test for NULL msg, not zero length message */
GPSD_LOG(LOG_ERROR, &session->context->errout,
"GREIS: nothing to write\n");
return -1;
}
/* Account for length + checksum marker + checksum + \r + \n + \0 */
if (msglen + 6 > sizeof(session->msgbuf)) {
GPSD_LOG(LOG_ERROR, &session->context->errout,
"GREIS: msgbuf is smaller than write length %zu\n", msglen);
return -1;
}
if (msg != NULL)
memcpy(&session->msgbuf[0], msg, msglen);
if (msglen == 0) {
/* This is a dummy write, don't give a checksum. */
session->msgbuf[0] = '\n';
session->msgbuflen = 1;
GPSD_LOG(LOG_PROG, &session->context->errout,
"GREIS: Dummy write\n");
} else {
unsigned char checksum;
session->msgbuflen = msglen;
session->msgbuf[session->msgbuflen++] = '@'; /* checksum marker */
/* calculate checksum with @, place at end, and set length to write */
checksum = greis_checksum((unsigned char *)session->msgbuf,
session->msgbuflen);
(void)snprintf(checksum_str, sizeof(checksum_str), "%02X", checksum);
session->msgbuf[session->msgbuflen++] = checksum_str[0];
session->msgbuf[session->msgbuflen++] = checksum_str[1];
session->msgbuf[session->msgbuflen++] = '\r';
session->msgbuf[session->msgbuflen++] = '\n';
GPSD_LOG(LOG_PROG, &session->context->errout,
"GREIS: Writing command '%.*s', checksum: %s\n",
(int)msglen, msg, checksum_str);
}
session->msgbuf[session->msgbuflen] = '\0';
count = gpsd_write(session, session->msgbuf, session->msgbuflen);
if (count != (ssize_t)session->msgbuflen)