2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
16 * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
23 #include <sys/types.h>
25 #include <sys/ioctl.h>
38 #include <libubox/utils.h>
43 #define MAX_NMEA_PARAM 20
44 #define MAX_TIME_OFFSET 2
45 #define MAX_BAD_TIME 3
50 } nmea_params
[MAX_NMEA_PARAM
];
52 static int nmea_bad_time
;
53 char longitude
[32] = { 0 }, latitude
[32] = { 0 }, course
[16] = { 0 }, speed
[16] = { 0 }, elivation
[16] = { 0 };
59 char *ids
[] = { "ERROR", "WARNING", "NOTICE", };
61 if (nmea_params
[3].num
< 0 || nmea_params
[3].num
> 2)
62 nmea_params
[3].num
= 0;
64 DEBUG(3, "%s: %s\n", ids
[nmea_params
[3].num
], nmea_params
[4].str
);
73 if (*nmea_params
[2].str
!= 'A') {
75 DEBUG(4, "waiting for valid signal\n");
80 memset(&tm
, 0, sizeof(tm
));
83 if (!strptime(nmea_params
[1].str
, "%H%M%S", &tm
))
84 ERROR("failed to parse time\n");
85 else if (!strptime(nmea_params
[9].str
, "%d%m%y", &tm
))
86 ERROR("failed to parse date\n");
88 /* is there a libc api for the tz adjustment ? */
89 struct timeval tv
= { mktime(&tm
), 0 };
92 strftime(tmp
, 256, "%D %02H:%02M:%02S", &tm
);
93 DEBUG(3, "date: %s UTC\n", tmp
);
95 tv
.tv_sec
-= timezone
;
99 gettimeofday(&cur
, NULL
);
101 if (abs(cur
.tv_sec
- tv
.tv_sec
) > MAX_TIME_OFFSET
) {
102 if (++nmea_bad_time
> MAX_BAD_TIME
) {
103 LOG("system time differs from GPS time by more than %d seconds. Using %s UTC as the new time\n", MAX_TIME_OFFSET
, tmp
);
104 settimeofday(&tv
, NULL
);
111 if (strlen(nmea_params
[3].str
) != 9 || strlen(nmea_params
[5].str
) != 10) {
112 ERROR("lat/lng have invalid string length\n");
114 int latd
, latm
, lats
;
115 int lngd
, lngm
, lngs
;
117 DEBUG(4, "position: %s, %s\n",
118 nmea_params
[3].str
, nmea_params
[5].str
);
119 latm
= atoi(&nmea_params
[3].str
[2]);
120 nmea_params
[3].str
[2] = '\0';
121 latd
= atoi(nmea_params
[3].str
);
122 lats
= atoi(&nmea_params
[3].str
[5]);
123 if (*nmea_params
[4].str
!= 'N')
126 lngm
= atoi(&nmea_params
[5].str
[3]);
127 nmea_params
[5].str
[3] = '\0';
128 lngd
= atoi(nmea_params
[5].str
);
129 lngs
= atoi(&nmea_params
[5].str
[6]);
130 if (*nmea_params
[6].str
!= 'E')
141 #define ms_to_deg(x, y) (((x * 10000) + y) / 60)
143 DEBUG(4, "position: %d°%d.%04d, %d°%d.%04d\n",
144 latd
, latm
, lats
, lngd
, lngm
, lngs
);
145 DEBUG(4, "position: %d°%d'%.1f\" %d°%d'%.1f\"\n",
146 latd
, latm
, flats
, lngd
, lngm
, flngs
);
148 snprintf(latitude
, sizeof(latitude
), "%d.%04d", latd
, ms_to_deg(latm
, lats
));
149 snprintf(longitude
, sizeof(longitude
), "%d.%04d", lngd
, ms_to_deg(lngm
, lngs
));
150 DEBUG(3, "position: %s %s\n", latitude
, longitude
);
160 strncpy(elivation
, nmea_params
[9].str
, sizeof(elivation
));
161 DEBUG(4, "height: %s\n", elivation
);
169 strncpy(course
, nmea_params
[1].str
, sizeof(course
));
170 strncpy(speed
, nmea_params
[6].str
, sizeof(speed
));
171 DEBUG(4, "course: %s\n", course
);
172 DEBUG(4, "speed: %s\n", speed
);
175 static struct nmea_msg
{
178 void (*handler
) (void);
183 .handler
= nmea_txt_cb
,
187 .handler
= nmea_rmc_cb
,
191 .handler
= nmea_gga_cb
,
195 .handler
= nmea_vtg_cb
,
200 nmea_verify_checksum(char *s
)
202 char *csum
= strrchr(s
, '*');
210 isum
= strtol(csum
, NULL
, 16);
222 nmea_tokenize(char *msg
)
225 char *tok
= strsep(&msg
, ",");
227 while (tok
&& cnt
< MAX_NMEA_PARAM
) {
228 nmea_params
[cnt
].str
= tok
;
229 nmea_params
[cnt
].num
= atoi(tok
);
231 tok
= strsep(&msg
, ",");
238 nmea_process(char *a
)
243 if (strncmp(a
, "$GP", 3))
247 csum
= strrchr(a
, '*');
251 if (nmea_verify_checksum(a
)) {
252 ERROR("nmea message has invalid checksum\n");
256 cnt
= nmea_tokenize(&a
[2]);
258 ERROR("failed to tokenize %s\n", a
);\
262 for (i
= 0; i
< ARRAY_SIZE(nmea_msgs
); i
++) {
263 if (strcmp(nmea_params
[0].str
, nmea_msgs
[i
].msg
))
265 if (nmea_msgs
[i
].cnt
<= cnt
)
266 nmea_msgs
[i
].handler();
268 ERROR("%s datagram has wrong parameter count got %d but expected %d\n", nmea_msgs
[i
].msg
, cnt
, nmea_msgs
[i
].cnt
);
274 nmea_consume(struct ustream
*s
, char **a
)
276 char *eol
= strstr(*a
, "\n");
285 ustream_consume(s
, eol
- *a
);
292 nmea_msg_cb(struct ustream
*s
, int bytes
)
295 char *a
= ustream_get_read_buf(s
, &len
);
297 while (!nmea_consume(s
, &a
))
301 static void nmea_notify_cb(struct ustream
*s
)
306 ERROR("tty error, shutting down\n");
311 nmea_open(char *dev
, struct ustream_fd
*s
, speed_t speed
)
316 tty
= open(dev
, O_RDWR
| O_NOCTTY
| O_NONBLOCK
);
318 ERROR("%s: device open failed: %s\n", dev
, strerror(errno
));
322 tcgetattr(tty
, &tio
);
323 tio
.c_cflag
|= CREAD
;
325 tio
.c_iflag
|= IGNPAR
;
326 tio
.c_lflag
&= ~(ICANON
);
327 tio
.c_lflag
&= ~(ECHO
);
328 tio
.c_lflag
&= ~(ECHOE
);
329 tio
.c_lflag
&= ~(ISIG
);
332 cfsetispeed(&tio
, speed
);
333 cfsetospeed(&tio
, speed
);
334 tcsetattr(tty
, TCSANOW
, &tio
);
336 s
->stream
.string_data
= true;
337 s
->stream
.notify_read
= nmea_msg_cb
;
338 s
->stream
.notify_state
= nmea_notify_cb
;
340 ustream_fd_init(s
, tty
);
342 tcflush(tty
, TCIFLUSH
);