MC7455: Start and mantain a connection in an embedded system

IoT Modules MC/EM Series
1

Hello,

I’m developing an automotive embedded system with a custom distro (Yocto Project) and the official QMI GobiNet and GobiSerial drivers (MC7455). I want to make the 4G interface available as soon as possible thus I wrote an initscript that sends the modem the necessary AT commands via microcom and then runs a dhclient on the resulting interface. Nevertheless, this method is far from being flawless; due to the nature of my device (garage, rural area, mountain…), sometimes, there’s not (enough) signal coverage at boot and consequently the connection establishment fails and the interface keeps down forever. The same happens if the APN closes the connection/the coverage is lost; the connection never goes up again.

So, the question is: Which is the proper method of managing (connect, disconnect, reconnect and check status) the connection in theses situations? Is there any official (or not) tool that would do the trick?

As far as I know, Gobi drivers are not supported by NM (nor MM) or libqmi.

Thank you in advance!

Regards
Daniel

2

probably you need to write a script to check AT!GSTATUS? if it is attached after boot up.
After that you can use AT!SCACT=1,1 to establish the data connection.