[layer23] Completed GPS reading process

This includes "double" values of logitude and latitude, as well as time
stamp, and if the values are valid or not (GPS fix).

3 files changed, 87 insertions, 6 deletions

diff --git a/src/host/layer23/include/osmocom/bb/common/logging.h b/src/host/layer23/include/osmocom/bb/common/logging.h
index 683c6858..eb9f4821 100644
--- a/src/host/layer23/include/osmocom/bb/common/logging.h
+++ b/src/host/layer23/include/osmocom/bb/common/logging.h
@@ -20,6 +20,7 @@ enum {
 	DSAP,
 	DSUM,
 	DSIM,
+	DGPS,
 };
 
 extern const struct log_info log_info;
diff --git a/src/host/layer23/include/osmocom/bb/mobile/gps.h b/src/host/layer23/include/osmocom/bb/mobile/gps.h
index a62eab77..b3b43351 100644
--- a/src/host/layer23/include/osmocom/bb/mobile/gps.h
+++ b/src/host/layer23/include/osmocom/bb/mobile/gps.h
@@ -20,9 +20,15 @@
  */
 
 struct gps {
-	uint8_t enable;
-	char device[32];
-	uint32_t baud;
+	/* GPS device */
+	uint8_t		enable;
+	char		device[32];
+	uint32_t	baud;
+
+	/* current data */
+	uint8_t		valid; /* we have a fix */
+	time_t		gmt; /* GMT time when position was received */
+	double		latitude, longitude;
 };
 
 extern struct gps gps;
diff --git a/src/host/layer23/src/mobile/gps.c b/src/host/layer23/src/mobile/gps.c
index 520aff82..c66da6db 100644
--- a/src/host/layer23/src/mobile/gps.c
+++ b/src/host/layer23/src/mobile/gps.c
@@ -25,16 +25,22 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <errno.h>
+#include <time.h>
 
 #include <osmocore/utils.h>
 
 #include <osmocom/bb/common/osmocom_data.h>
+#include <osmocom/bb/common/logging.h>
 #include <osmocom/bb/mobile/gps.h>
 
 struct gps gps = {
 	0,
 	"/dev/ttyACM0",
-	0
+	0,
+
+	0,
+	0,
+	0,0,
 };
 
 static struct bsc_fd gps_bfd;
@@ -42,6 +48,11 @@ static struct termios gps_termios, gps_old_termios;
 
 static int gps_line(char *line)
 {
+	time_t gps_now, host_now;
+	struct tm *tm;
+	int32_t diff;
+	double latitude, longitude;
+
 	if (!!strncmp(line, "$GPGLL", 6))
 		return 0;
 	line += 7;
@@ -50,8 +61,66 @@ static int gps_line(char *line)
 	line[37] = '\0';
 	/* ddmm.mmmm,N,dddmm.mmmm,E,hhmmss.mmm,A */
 
-	printf("'%s'\n", line);
-
+	/* valid position */
+	if (line[36] != 'A') {
+		LOGP(DGPS, LOGL_INFO, "%s (invalid)\n", line);
+		gps.valid = 0;
+	}
+	gps.valid = 1;
+
+	/* time stamp */
+	gps_now = line[30] - '0';
+	gps_now += (line[29] - '0') * 10;
+	gps_now += (line[28] - '0') * 60;
+	gps_now += (line[27] - '0') * 600;
+	gps_now += (line[26] - '0') * 3600;
+	gps_now += (line[25] - '0') * 36000;
+	time(&host_now);
+	/* calculate the number of seconds the host differs from GPS */
+	diff = host_now % 86400 - gps_now;
+	if (diff < 0)
+		diff += 86400;
+	if (diff >= 43200)
+		diff -= 86400;
+	/* apply the "date" part to the GPS time */
+	gps_now = host_now - diff;
+	gps.gmt = gps_now;
+	tm = localtime(&gps_now);
+
+	/* position */
+	latitude = (double)(line[0] - '0') * 10.0;
+	latitude += (double)(line[1] - '0');
+	latitude += (double)(line[2] - '0') / 6.0;
+	latitude += (double)(line[3] - '0') / 60.0;
+	latitude += (double)(line[5] - '0') / 600.0;
+	latitude += (double)(line[6] - '0') / 6000.0;
+	latitude += (double)(line[7] - '0') / 60000.0;
+	latitude += (double)(line[8] - '0') / 600000.0;
+	if (line[10] == 'S')
+		latitude = 0.0 - latitude;
+	gps.latitude = latitude;
+	longitude = (double)(line[12] - '0') * 100.0;
+	longitude += (double)(line[13] - '0') * 10.0;
+	longitude += (double)(line[14] - '0');
+	longitude += (double)(line[15] - '0') / 6.0;
+	longitude += (double)(line[16] - '0') / 60.0;
+	longitude += (double)(line[18] - '0') / 600.0;
+	longitude += (double)(line[19] - '0') / 6000.0;
+	longitude += (double)(line[20] - '0') / 60000.0;
+	longitude += (double)(line[21] - '0') / 600000.0;
+	if (line[23] == 'W')
+		longitude = 360.0 - longitude;
+	gps.longitude = longitude;
+	
+	LOGP(DGPS, LOGL_INFO, "%s\n", line);
+	LOGP(DGPS, LOGL_INFO, " time=%02d:%02d:%02d %04d-%02d-%02d, "
+		"diff-to-host=%d, latitude=%do%.4f, longitude=%do%.4f\n",
+		tm->tm_hour, tm->tm_min, tm->tm_sec, tm->tm_year + 1900,
+		tm->tm_mday, tm->tm_mon + 1, diff,
+		(int)gps.latitude,
+		(gps.latitude - ((int)gps.latitude)) * 60.0,
+		(int)gps.longitude,
+		(gps.longitude - ((int)gps.longitude)) * 60.0);
 	return 0;
 }
 
@@ -112,6 +181,9 @@ int gps_open(void)
 
 	if (gps_bfd.fd > 0)
 		return 0;
+
+	LOGP(DGPS, LOGL_INFO, "Open GPS device '%s'\n", gps.device);
+
 	gps_bfd.data = NULL;
 	gps_bfd.when = BSC_FD_READ;
 	gps_bfd.cb = gps_cb;
@@ -159,6 +231,8 @@ void gps_close(void)
 	if (gps_bfd.fd <= 0)
 		return;
 
+	LOGP(DGPS, LOGL_INFO, "Close GPS device\n");
+
 	bsc_unregister_fd(&gps_bfd);
 
 	if (isatty(gps_bfd.fd))