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gps.c
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/*
** Copyright 2006, The Android Open Source Project
** Copyright 2009, Michael Trimarchi <[email protected]>
** Copyright 2015, Keith Conger <[email protected]>
**
** This program is free software; you can redistribute it and/or modify it under
** the terms of the GNU General Public License as published by the Free
** Software Foundation; either version 2, or (at your option) any later
** version.
**
** This program is distributed in the hope that it will be useful, but WITHOUT
** ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
** FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
** more details.
**
** You should have received a copy of the GNU General Public License along with
** this program; if not, write to the Free Software Foundation, Inc., 59
** Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**/
#include <errno.h>
#include <pthread.h>
#include <termios.h>
#include <fcntl.h>
#include <sys/epoll.h>
#include <math.h>
#include <time.h>
#include <signal.h>
#include <unistd.h>
#define LOG_TAG "gps_serial"
#include <cutils/log.h>
#include <cutils/sockets.h>
#include <cutils/properties.h>
#include <hardware/gps.h>
#if (12 <= __ANDROID_API__) || defined(_BSD_SOURCE) || defined(_SVID_SOURCE) || defined(_DEFAULT_SOURCE)
#define _USE_TIMEGM
#endif
/* this is the state of our connection to the qemu_gpsd daemon */
typedef struct {
int init;
int fd;
GpsCallbacks *callbacks;
GpsStatus status;
pthread_t thread;
int control[2];
} GpsState;
static GpsState _gps_state[1];
static int id_in_fixed[12];
static unsigned short period_in_ms;
static long time_sync;
//#define GPS_DEBUG 1
#define DFR(...) ALOGD(__VA_ARGS__)
#if GPS_DEBUG
# define D(...) ALOGD(__VA_ARGS__)
#else
# define D(...) ((void)0)
#endif
#define GPS_DEV_SLOW_UPDATE_RATE (10)
#define GPS_DEV_HIGH_UPDATE_RATE (1)
static void gps_dev_set_meas_rate(int fd, unsigned short period_ms);
/*****************************************************************/
/*****************************************************************/
/***** *****/
/***** N M E A T O K E N I Z E R *****/
/***** *****/
/*****************************************************************/
/*****************************************************************/
#define MAX_NMEA_TOKENS 32
typedef struct {
const char* p;
const char* end;
} Token;
typedef struct {
int count;
Token tokens[ MAX_NMEA_TOKENS ];
} NmeaTokenizer;
static int
nmea_tokenizer_init( NmeaTokenizer* t, const char* p, const char* end )
{
int count = 0;
//char* q;
// the initial '$' is optional
if (p < end && p[0] == '$')
p += 1;
// remove trailing newline
if (end > p && end[-1] == '\n') {
end -= 1;
if (end > p && end[-1] == '\r')
end -= 1;
}
// get rid of checksum at the end of the sentence
if (end >= p+3 && end[-3] == '*') {
end -= 3;
}
while (p < end) {
const char* q = p;
q = memchr(p, ',', end-p);
if (q == NULL)
q = end;
if (count < MAX_NMEA_TOKENS) {
t->tokens[count].p = p;
t->tokens[count].end = q;
count += 1;
}
if (q < end)
q += 1;
p = q;
}
t->count = count;
return count;
}
static Token
nmea_tokenizer_get( NmeaTokenizer* t, int index )
{
Token tok;
if (index < 0 || index >= t->count || index >= MAX_NMEA_TOKENS)
tok.p = tok.end = "";
else
tok = t->tokens[index];
return tok;
}
static int
str2int( const char* p, const char* end )
{
int result = 0;
int len = end - p;
for ( ; len > 0; len--, p++ ) {
int c;
if (p >= end)
goto Fail;
c = *p - '0';
if ((unsigned)c >= 10)
goto Fail;
result = result*10 + c;
}
return result;
Fail:
return -1;
}
static double
str2float( const char* p, const char* end )
{
size_t len = end - p;
char temp[16];
if (len >= sizeof(temp))
return 0.;
memcpy( temp, p, len );
temp[len] = '\0';
return strtod( temp, NULL );
}
/*****************************************************************/
/*****************************************************************/
/***** *****/
/***** N M E A P A R S E R *****/
/***** *****/
/*****************************************************************/
/*****************************************************************/
#define NMEA_MAX_SIZE 255
typedef struct {
int pos;
int overflow;
int utc_year;
int utc_mon;
int utc_day;
//time_t utc_diff;
bool gsa; // TRUE if GSA sentence was detected
GpsLocation fix;
GpsSvStatus sv_status;
gps_location_callback callback;
char in[ NMEA_MAX_SIZE+1 ];
} NmeaReader;
void update_gps_status(GpsStatusValue val)
{
GpsState* state = _gps_state;
//Should be made thread safe...
state->status.status=val;
if (state->callbacks->status_cb)
state->callbacks->status_cb(&state->status);
}
void update_gps_svstatus(GpsSvStatus *val)
{
GpsState* state = _gps_state;
//Should be made thread safe...
if (state->callbacks->sv_status_cb)
state->callbacks->sv_status_cb(val);
}
void update_gps_location(GpsLocation *fix)
{
GpsState* state = _gps_state;
//Should be made thread safe...
if (state->callbacks->location_cb)
state->callbacks->location_cb(fix);
}
#ifndef _USE_TIMEGM
static time_t get_utc_diff()
{
// 3rd January, 1970, Time: 00:00:00
static struct tm tm = { 0, 0, 0, 3, 0, 70, 0, 0, -1 };
return (2 * 24 * 3600) - mktime(&tm);
}
#endif // _USE_TIMEGM
static void
nmea_reader_init( NmeaReader* r )
{
memset( r, 0, sizeof(*r) );
r->pos = 0;
r->overflow = 0;
r->utc_year = -1;
r->utc_mon = -1;
r->utc_day = -1;
r->gsa = false;
r->callback = NULL;
r->fix.size = sizeof(r->fix);
//nmea_reader_update_utc_diff( r );
}
static int
nmea_reader_update_time( NmeaReader* r, Token tok, time_t *gmt )
{
int hour, minute;
double seconds;
struct tm tm;
if (tok.p + 6 > tok.end)
return -1;
if (r->utc_year < 0) {
// no date yet, get current one
time_t now = time(NULL);
gmtime_r( &now, &tm );
r->utc_year = tm.tm_year + 1900;
r->utc_mon = tm.tm_mon + 1;
r->utc_day = tm.tm_mday;
}
tm.tm_hour = str2int(tok.p, tok.p+2);
tm.tm_min = str2int(tok.p+2, tok.p+4);
tm.tm_sec = (int) str2float(tok.p+4, tok.end);
tm.tm_year = r->utc_year - 1900;
tm.tm_mon = r->utc_mon - 1;
tm.tm_mday = r->utc_day;
tm.tm_isdst = -1;
#ifdef _USE_TIMEGM
*gmt = timegm( &tm );
#else
*gmt = mktime( &tm ) + get_utc_diff();
#endif
r->fix.timestamp = (long long) *gmt * 1000;
return 0;
}
static int
nmea_reader_update_date( NmeaReader* r, Token date_tok, Token time_tok )
{
Token tok = date_tok;
int day, mon, year;
if (tok.p + 6 != tok.end) {
D("Date not properly formatted: '%.*s'", tok.end-tok.p, tok.p);
return -1;
}
day = str2int(tok.p, tok.p+2);
mon = str2int(tok.p+2, tok.p+4);
year = str2int(tok.p+4, tok.p+6) + 2000;
if ((day|mon|year) < 0) {
D("Date not properly formatted: '%.*s'", tok.end-tok.p, tok.p);
return -1;
}
r->utc_year = year;
r->utc_mon = mon;
r->utc_day = day;
time_t gmt;
int result = nmea_reader_update_time( r, time_tok, &gmt );
if (0 < time_sync)
{
long dif = (long) (time(NULL) - gmt);
if (dif < -time_sync || time_sync < dif)
{
D("System time synchronized with the GPS");
struct timeval tv = { gmt, 0 };
settimeofday(&tv, NULL);
}
}
return result;
}
static double
convert_from_hhmm( Token tok )
{
double val = str2float(tok.p, tok.end);
int degrees = (int)(floor(val) / 100);
double minutes = val - degrees*100.;
double dcoord = degrees + minutes / 60.0;
return dcoord;
}
static int
nmea_reader_update_latlong( NmeaReader* r,
Token latitude,
char latitudeHemi,
Token longitude,
char longitudeHemi )
{
double lat, lon;
Token tok;
tok = latitude;
if (tok.p + 6 > tok.end) {
D("Latitude is too short: '%.*s'", tok.end-tok.p, tok.p);
return -1;
}
lat = convert_from_hhmm(tok);
if (latitudeHemi == 'S')
lat = -lat;
tok = longitude;
if (tok.p + 6 > tok.end) {
D("Longitude is too short: '%.*s'", tok.end-tok.p, tok.p);
return -1;
}
lon = convert_from_hhmm(tok);
if (longitudeHemi == 'W')
lon = -lon;
r->fix.flags |= GPS_LOCATION_HAS_LAT_LONG;
r->fix.latitude = lat;
r->fix.longitude = lon;
return 0;
}
static int
nmea_reader_update_altitude( NmeaReader* r,
Token altitude,
Token units )
{
//double alt;
Token tok = altitude;
if (tok.p >= tok.end)
return -1;
r->fix.flags |= GPS_LOCATION_HAS_ALTITUDE;
r->fix.altitude = str2float(tok.p, tok.end);
return 0;
}
static int nmea_reader_update_accuracy(NmeaReader* r, Token accuracy, bool is_fix)
{
//double acc;
Token tok = accuracy;
if (tok.p >= tok.end)
return -1;
r->fix.accuracy = (float) str2float(tok.p, tok.end);
if (99.0f < r->fix.accuracy)
return 0;
if (is_fix)
r->fix.flags |= GPS_LOCATION_HAS_ACCURACY;
return 0;
}
static int
nmea_reader_update_bearing( NmeaReader* r,
Token bearing )
{
//double alt;
Token tok = bearing;
if (tok.p >= tok.end)
return -1;
r->fix.flags |= GPS_LOCATION_HAS_BEARING;
r->fix.bearing = str2float(tok.p, tok.end);
return 0;
}
static int
nmea_reader_update_speed( NmeaReader* r,
Token speed )
{
//double alt;
Token tok = speed;
if (tok.p >= tok.end)
return -1;
r->fix.flags |= GPS_LOCATION_HAS_SPEED;
r->fix.speed = (float) (str2float(tok.p, tok.end) * (1.852 / 3.6));
return 0;
}
static int
nmea_reader_update_svs( NmeaReader* r, int inview, int num, int i, Token prn, Token elevation, Token azimuth, Token snr )
{
int o;
int prnid;
i = (num - 1)*4 + i;
if (i < inview) {
r->sv_status.sv_list[i].prn=str2int(prn.p,prn.end);
r->sv_status.sv_list[i].elevation=str2int(elevation.p,elevation.end);
r->sv_status.sv_list[i].azimuth=str2int(azimuth.p,azimuth.end);
r->sv_status.sv_list[i].snr=str2int(snr.p,snr.end);
for (o=0;o<12;o++){
if (id_in_fixed[o]==str2int(prn.p,prn.end)){
prnid = str2int(prn.p, prn.end);
r->sv_status.used_in_fix_mask |= (1ul << (prnid-1));
}
}
}
return 0;
}
static void
nmea_reader_parse( NmeaReader* r )
{
/* we received a complete sentence, now parse it to generate
* a new GPS fix...
*/
NmeaTokenizer tzer[1];
Token tok;
struct timeval tv;
D("Received: '%.*s'", r->pos, r->in);
if (r->pos < 9) {
D("Too short. discarded.");
return;
}
r->in[r->pos] = 0;
gettimeofday(&tv, NULL);
if (_gps_state->init)
_gps_state->callbacks->nmea_cb(tv.tv_sec*1000+tv.tv_usec/1000, r->in, r->pos);
nmea_tokenizer_init(tzer, r->in, r->in + r->pos);
#if GPS_DEBUG
{
int n;
D("Found %d tokens", tzer->count);
for (n = 0; n < tzer->count; n++) {
Token tok = nmea_tokenizer_get(tzer,n);
D("%2d: '%.*s'", n, tok.end-tok.p, tok.p);
}
}
#endif
tok = nmea_tokenizer_get(tzer, 0);
if (tok.p + 5 > tok.end) {
D("Sentence id '%.*s' too short, ignored.", tok.end-tok.p, tok.p);
return;
}
// ignore first two characters.
tok.p += 2;
bool send_msg = false;
if ( !memcmp(tok.p, "GGA", 3) ) {
// GPS fix
Token tok_time = nmea_tokenizer_get(tzer,1);
Token tok_latitude = nmea_tokenizer_get(tzer,2);
Token tok_latitudeHemi = nmea_tokenizer_get(tzer,3);
Token tok_longitude = nmea_tokenizer_get(tzer,4);
Token tok_longitudeHemi = nmea_tokenizer_get(tzer,5);
Token tok_fix = nmea_tokenizer_get(tzer,6);
Token tok_accuracy = nmea_tokenizer_get(tzer,8);
Token tok_altitude = nmea_tokenizer_get(tzer,9);
Token tok_altitudeUnits = nmea_tokenizer_get(tzer,10);
int fix = str2int(tok_fix.p, tok_fix.end);
if (0 < fix)
{
time_t gmt;
nmea_reader_update_time(r, tok_time, &gmt);
nmea_reader_update_latlong(r, tok_latitude, tok_latitudeHemi.p[0], tok_longitude, tok_longitudeHemi.p[0]);
nmea_reader_update_altitude(r, tok_altitude, tok_altitudeUnits);
}
if (!r->gsa)
{
nmea_reader_update_accuracy(r, tok_accuracy, 0 < fix);
send_msg = true;
}
} else if ( !memcmp(tok.p, "GSA", 3) ) {
/*
1 = Mode:
M=Manual, forced to operate in 2D or 3D
A=Automatic, 3D/2D
2 = Mode:
1=Fix not available
2=2D
3=3D
3-14 = IDs of SVs used in position fix (null for unused fields)
15 = PDOP
16 = HDOP
17 = VDOP
*/
if (r->gsa)
{
//Token tok_mode = nmea_tokenizer_get(tzer,1);
Token tok_fix = nmea_tokenizer_get(tzer,2);
//Token tok_id = nmea_tokenizer_get(tzer,3);
//Token tok_pdop = nmea_tokenizer_get(tzer,15);
Token tok_hdop = nmea_tokenizer_get(tzer,16);
//Token tok_vdop = nmea_tokenizer_get(tzer,17);
int fix = str2int(tok_fix.p, tok_fix.end);
if (fix == 2)
r->fix.flags &= ~GPS_LOCATION_HAS_ALTITUDE;
nmea_reader_update_accuracy(r, tok_hdop, 1 < fix);
send_msg = true;
int i;
for (i = 0; i < 12; i++) {
Token tok_id = nmea_tokenizer_get(tzer, 3 + i);
if (tok_id.end > tok_id.p) {
id_in_fixed[i] = str2int(tok_id.p, tok_id.end);
D("Satellite used '%.*s'", tok_id.end - tok_id.p, tok_id.p);
}
}
}
r->gsa = true;
} else if ( !memcmp(tok.p, "GSV", 3) ) {
/*
1 = Total number of messages of this type in this cycle
2 = Message number
3 = Total number of SVs in view
4 = SV PRN number
5 = Elevation in degrees, 90 maximum
6 = Azimuth, degrees from true north, 000 to 359
7 = SNR, 00-99 dB (null when not tracking)
8-11 = Information about second SV, same as field 4-7
12-15= Information about third SV, same as field 4-7
16-19= Information about fourth SV, same as field 4-7
*/
//Satellites are handled by RPC-side code.
Token tok_num_messages = nmea_tokenizer_get(tzer,1);
Token tok_msg_number = nmea_tokenizer_get(tzer,2);
Token tok_svs_inview = nmea_tokenizer_get(tzer,3);
Token tok_sv1_prn_num = nmea_tokenizer_get(tzer,4);
Token tok_sv1_elevation = nmea_tokenizer_get(tzer,5);
Token tok_sv1_azimuth = nmea_tokenizer_get(tzer,6);
Token tok_sv1_snr = nmea_tokenizer_get(tzer,7);
Token tok_sv2_prn_num = nmea_tokenizer_get(tzer,8);
Token tok_sv2_elevation = nmea_tokenizer_get(tzer,9);
Token tok_sv2_azimuth = nmea_tokenizer_get(tzer,10);
Token tok_sv2_snr = nmea_tokenizer_get(tzer,11);
Token tok_sv3_prn_num = nmea_tokenizer_get(tzer,12);
Token tok_sv3_elevation = nmea_tokenizer_get(tzer,13);
Token tok_sv3_azimuth = nmea_tokenizer_get(tzer,14);
Token tok_sv3_snr = nmea_tokenizer_get(tzer,15);
Token tok_sv4_prn_num = nmea_tokenizer_get(tzer,16);
Token tok_sv4_elevation = nmea_tokenizer_get(tzer,17);
Token tok_sv4_azimuth = nmea_tokenizer_get(tzer,18);
Token tok_sv4_snr = nmea_tokenizer_get(tzer,19);
int num_messages = str2int(tok_num_messages.p,tok_num_messages.end);
int msg_number = str2int(tok_msg_number.p,tok_msg_number.end);
int svs_inview = str2int(tok_svs_inview.p,tok_svs_inview.end);
D("GSV %d %d %d", num_messages, msg_number, svs_inview );
if (msg_number==1){
r->sv_status.used_in_fix_mask = 0ul;
}
nmea_reader_update_svs( r, svs_inview, msg_number, 0, tok_sv1_prn_num, tok_sv1_elevation, tok_sv1_azimuth, tok_sv1_snr );
nmea_reader_update_svs( r, svs_inview, msg_number, 1, tok_sv2_prn_num, tok_sv2_elevation, tok_sv2_azimuth, tok_sv2_snr );
nmea_reader_update_svs( r, svs_inview, msg_number, 2, tok_sv3_prn_num, tok_sv3_elevation, tok_sv3_azimuth, tok_sv3_snr );
nmea_reader_update_svs( r, svs_inview, msg_number, 3, tok_sv4_prn_num, tok_sv4_elevation, tok_sv4_azimuth, tok_sv4_snr );
r->sv_status.num_svs=svs_inview;
if (num_messages==msg_number)
update_gps_svstatus(&r->sv_status);
} else if ( !memcmp(tok.p, "RMC", 3) ) {
Token tok_time = nmea_tokenizer_get(tzer,1);
Token tok_fixStatus = nmea_tokenizer_get(tzer,2);
Token tok_latitude = nmea_tokenizer_get(tzer,3);
Token tok_latitudeHemi = nmea_tokenizer_get(tzer,4);
Token tok_longitude = nmea_tokenizer_get(tzer,5);
Token tok_longitudeHemi = nmea_tokenizer_get(tzer,6);
Token tok_speed = nmea_tokenizer_get(tzer,7);
Token tok_bearing = nmea_tokenizer_get(tzer,8);
Token tok_date = nmea_tokenizer_get(tzer,9);
D("in RMC, fixStatus=%c", tok_fixStatus.p[0]);
if (tok_fixStatus.p[0] == 'A') {
nmea_reader_update_date( r, tok_date, tok_time );
nmea_reader_update_latlong( r, tok_latitude,
tok_latitudeHemi.p[0],
tok_longitude,
tok_longitudeHemi.p[0] );
nmea_reader_update_bearing( r, tok_bearing );
nmea_reader_update_speed ( r, tok_speed );
}
} else if ( !memcmp(tok.p, "VTG", 3) ) {
Token tok_fixStatus = nmea_tokenizer_get(tzer,9);
if (tok_fixStatus.p[0] != '\0' && tok_fixStatus.p[0] != 'N') {
Token tok_bearing = nmea_tokenizer_get(tzer,1);
Token tok_speed = nmea_tokenizer_get(tzer,5);
nmea_reader_update_bearing( r, tok_bearing );
nmea_reader_update_speed ( r, tok_speed );
}
} else {
tok.p -= 2;
D("Unknown sentence '%.*s", tok.end-tok.p, tok.p);
}
#if GPS_DEBUG
if (r->fix.flags) {
char temp[256];
char* p = temp;
char* end = p + sizeof(temp);
struct tm utc;
p += snprintf( p, end-p, "Sending fix" );
if (r->fix.flags & GPS_LOCATION_HAS_LAT_LONG) {
p += snprintf(p, end-p, " lat=%g lon=%g", r->fix.latitude, r->fix.longitude);
}
if (r->fix.flags & GPS_LOCATION_HAS_ALTITUDE) {
p += snprintf(p, end-p, " altitude=%g", r->fix.altitude);
}
if (r->fix.flags & GPS_LOCATION_HAS_SPEED) {
p += snprintf(p, end-p, " speed=%g", r->fix.speed);
}
if (r->fix.flags & GPS_LOCATION_HAS_BEARING) {
p += snprintf(p, end-p, " bearing=%g", r->fix.bearing);
}
if (r->fix.flags & GPS_LOCATION_HAS_ACCURACY) {
p += snprintf(p,end-p, " accuracy=%g", r->fix.accuracy);
}
gmtime_r( (time_t*) &r->fix.timestamp, &utc );
p += snprintf(p, end-p, " time=%s", asctime( &utc ) );
D("%s\n", temp);
}
#endif
if (send_msg)
{
if (_gps_state->callbacks->location_cb)
{
_gps_state->callbacks->location_cb(&r->fix);
r->fix.flags = 0;
}
else
{
D("No callback, keeping data until needed !");
}
}
}
static void
nmea_reader_addc( NmeaReader* r, int c )
{
if (r->overflow) {
r->overflow = (c != '\n');
return;
}
if (r->pos >= (int) sizeof(r->in)-1 ) {
r->overflow = 1;
r->pos = 0;
return;
}
r->in[r->pos] = (char)c;
r->pos += 1;
if (c == '\n') {
nmea_reader_parse( r );
r->pos = 0;
}
}
/*****************************************************************/
/*****************************************************************/
/***** *****/
/***** C O N N E C T I O N S T A T E *****/
/***** *****/
/*****************************************************************/
/*****************************************************************/
/* commands sent to the gps thread */
enum {
CMD_QUIT = 0,
CMD_START = 1,
CMD_STOP = 2
};
static void
gps_state_done( GpsState* s )
{
// tell the thread to quit, and wait for it
char cmd = CMD_QUIT;
void* dummy;
write( s->control[0], &cmd, 1 );
pthread_join(s->thread, &dummy);
// close the control socket pair
close( s->control[0] ); s->control[0] = -1;
close( s->control[1] ); s->control[1] = -1;
// close connection to the QEMU GPS daemon
close( s->fd ); s->fd = -1;
s->init = 0;
}
static void
gps_state_start( GpsState* s )
{
char cmd = CMD_START;
int ret;
do {
ret = write( s->control[0], &cmd, 1 );
} while (ret < 0 && errno == EINTR);
if (ret != 1)
D("%s: could not send CMD_START command: ret=%d: %s",
__FUNCTION__, ret, strerror(errno));
}
static void
gps_state_stop( GpsState* s )
{
char cmd = CMD_STOP;
int ret;
do { ret=write( s->control[0], &cmd, 1 ); }
while (ret < 0 && errno == EINTR);
if (ret != 1)
D("%s: could not send CMD_STOP command: ret=%d: %s",
__FUNCTION__, ret, strerror(errno));
}
static int
epoll_register( int epoll_fd, int fd )
{
struct epoll_event ev;
int ret, flags;
/* important: make the fd non-blocking */
flags = fcntl(fd, F_GETFL);
fcntl(fd, F_SETFL, flags | O_NONBLOCK);
ev.events = EPOLLIN;
ev.data.fd = fd;
do {
ret = epoll_ctl( epoll_fd, EPOLL_CTL_ADD, fd, &ev );
} while (ret < 0 && errno == EINTR);
return ret;
}
/* this is the main thread, it waits for commands from gps_state_start/stop and,
* when started, messages from the QEMU GPS daemon. these are simple NMEA sentences
* that must be parsed to be converted into GPS fixes sent to the framework
*/
static void
gps_state_thread( void* arg )
{
GpsState* state = (GpsState*) arg;
NmeaReader reader[1];
int epoll_fd = epoll_create(2);
int started = 0;
int gps_fd = state->fd;
int control_fd = state->control[1];
nmea_reader_init( reader );
// register control file descriptors for polling
epoll_register( epoll_fd, control_fd );
epoll_register( epoll_fd, gps_fd );
D("GPS thread running");
// now loop
for (;;) {
struct epoll_event events[2];
int ne, nevents;
nevents = epoll_wait( epoll_fd, events, 2, -1 );
if (nevents < 0) {
if (errno != EINTR)
ALOGE("epoll_wait() unexpected error: %s", strerror(errno));
continue;
}
for (ne = 0; ne < nevents; ne++) {
if ((events[ne].events & (EPOLLERR|EPOLLHUP)) != 0) {
ALOGE("EPOLLERR or EPOLLHUP after epoll_wait() !?");
return;
}
if ((events[ne].events & EPOLLIN) != 0) {
int fd = events[ne].data.fd;
if (fd == control_fd) {
char cmd = 255;
int ret;
D("GPS control fd event");
do {
ret = read( fd, &cmd, 1 );
} while (ret < 0 && errno == EINTR);
if (cmd == CMD_QUIT) {
D("GPS thread quitting on demand");
return;
} else if (cmd == CMD_START) {
if (!started) {
D("GPS thread starting location_cb=%p", state->callbacks->location_cb);
started = 1;
update_gps_status(GPS_STATUS_SESSION_BEGIN);
gps_dev_set_meas_rate(state->fd, period_in_ms);
}
} else if (cmd == CMD_STOP) {
if (started) {
D("GPS thread stopping");
started = 0;
update_gps_status(GPS_STATUS_SESSION_END);
gps_dev_set_meas_rate(state->fd, GPS_DEV_SLOW_UPDATE_RATE * 1000);
}
}
} else if (fd == gps_fd) {
char buff[32];
for (;;) {
int nn, ret;
ret = read( fd, buff, sizeof(buff) );
if (ret < 0) {
if (errno == EINTR)
continue;
if (errno != EWOULDBLOCK)
ALOGE("Error while reading from GPS daemon socket: %s:", strerror(errno));
break;
}
for (nn = 0; nn < ret; nn++)
nmea_reader_addc( reader, buff[nn] );
}
} else {
ALOGE("epoll_wait() returned unkown fd %d ?", fd);
}
}
}
}
}
static void
gps_state_init( GpsState* state, GpsCallbacks* callbacks )
{
char prop[PROPERTY_VALUE_MAX];
char device[256];
int ret;
int done = 0;
struct sigevent tmr_event;
state->init = 1;
state->control[0] = -1;
state->control[1] = -1;
state->fd = -1;
state->callbacks = callbacks;
D("gps_state_init");
// Look for a kernel-provided device name
if (property_get("ro.kernel.android.gps",prop,"") == 0) {
D("no kernel-provided gps device name");
return;
}
snprintf(device, sizeof(device), "/dev/%s",prop);
do {
state->fd = open( device, O_RDWR );
} while (state->fd < 0 && errno == EINTR);
if (state->fd < 0) {
ALOGE("could not open gps serial device %s: %s", device, strerror(errno) );
return;
}
D("GPS will read from %s", device);
period_in_ms = GPS_DEV_HIGH_UPDATE_RATE * 1000;
if (property_get("ro.kernel.android.gps.max_rate", prop, "") != 0)
{
unsigned long rate = strtoul(prop, NULL, 10);
if (0 < rate && rate < 66)
period_in_ms = (unsigned short) (rate * 1000);
else if (250 <= rate && rate < 65536)
period_in_ms = (unsigned short) rate;
}
D("measure rate is set to %u ms", period_in_ms);
time_sync = false;
if (property_get("ro.kernel.android.gps.time_sync", prop, "") != 0)
{
time_sync = atol(prop);
}
D("time_sync is %s", (time_sync) ? "enabled" : "disabled");
// Disable echo on serial lines
if ( isatty( state->fd ) ) {
struct termios ios;
tcgetattr( state->fd, &ios );
ios.c_lflag = 0; /* disable ECHO, ICANON, etc... */
ios.c_oflag &= (~ONLCR); /* Stop \n -> \r\n translation on output */
ios.c_iflag &= (~(ICRNL | INLCR)); /* Stop \r -> \n & \n -> \r translation on input */
ios.c_iflag |= (IGNCR | IXOFF); /* Ignore \r & XON/XOFF on input */
// Set baud rate and other flags
property_get("ro.kernel.android.gpsttybaud",prop,"9600");
if (strcmp(prop, "4800") == 0) {
ALOGE("Setting gps baud rate to 4800");
ios.c_cflag = B4800 | CRTSCTS | CS8 | CLOCAL | CREAD;
} else if (strcmp(prop, "9600") == 0) {