Phase 1 GPS driver
This article describes problems and solutions that were extremely important in the past but seems obsolete now. This content is kept mainly to reflect the history of the project.
In the very early shipment to 50 Phase 1 developers, a binary-only program for talking to the the GPS was accidentally included in /home/root/DM2/gps, (and presumably, the same binary would function on a P0 device). It was compiled to OABI format which now is obsolete as OM2007.2 builds are in EABI format, but developers suggested tricks to run it with chroot. These approaches seem now obsolete and the old binary seems even no longer easily available.
Binary Daemon GLLIN
For those few with the binary driver in the meantime, Pavel Machek provides the following script for recording an NMEA stream from the binary program.
#!/bin/sh echo 1 > /sys/class/leds/gta01\:vibrator/brightness killall gllin cat sleep 1 echo 0 > /sys/class/leds/gta01\:vibrator/brightness mknod /tmp/nmeaNP p cat /tmp/nmeaNP >> /tmp/gps.nmea & /home/root/DM2/gps/gllin -low 5 /home/root/DM2/gps/gllin -periodic 3
The binary program was compiled to OABI format which now is obsolete as OM2007.2 builds are in EABI format. You can still run the binary with chroot. Bartek Zdanowski wrote an aticle how to run GPS receiver. Alternatively ld-linux can be used to do the trick:
The ld-linux trick
You need the following files:
bin/gllin bin/gllin.sh lib/ld-linux.so.2 lib/libc.so.6 lib/libgcc_s.so.1 lib/libm.so.6 lib/libnss_dns.so.2 lib/libnss_files.so.2 lib/libpthread.so.0 lib/libresolv.so.2 lib/librt.so.1 lib/libstdc++.so.6 lib/libutil.so.1
The file bin/gllin.sh contains:
#!/bin/sh `pwd`/lib/ld-linux.so.2 --library-path `pwd`/lib `pwd`/bin/gllin -low 5 test -p /tmp/nmeaNP || ( rm -f /tmp/nmeaNP && mknod /tmp/nmeaNP p ) `pwd`/lib/ld-linux.so.2 --library-path `pwd`/lib `pwd`/bin/gllin -periodic 3
Be sure to start at least a `cat /tmp/nmeaNP` somewhere.
Another approach (chroot) is described in Gllin - here is also a link to an archive with all needed shared libraries in the right format.
Stack size 8864 bytes (9 KB)
means, nobody is reading on the pipe /tmp/nmeaNP, you probably forgot to start the `cat ...`.
gllin: early exit(3) in halInit()/681
is issued by the low-level hardware test but gllin works fine afterwards.
Do not use the option
because gllin then writes all data to file in /tmp which is a bad idea because /tmp is in kept in RAM so it's lost on reset. Also since the RAM is limited the logfile will eat up your memory.