Using Quectel EG25-G in ECM mode on PC

[Sebastian Sumpf]

Hi Pirmin,

On 9/2/22 10:59, Duss Pirmin wrote:
> Hi Sebastian
> 
> Thanks for you quick reply.
> 
> On 01.09.22 16:57, Sebastian Sumpf wrote:
> 
>> If the "AT" command gives you an "OK", you found the correct device. Note the 
>> modem exposes four UARTs. If this all is the case, a USB serial driver that 
>> exposes a terminal session  (like PL2303 [1]) is needed on Genode. I don't 
>> know exactly what kind of USB UART adapter the modem exposes right now. Maybe 
>> it's already PL2303. I will check.
> 
> Booting Ubuntu on the device (/dev/ttyUSB2) to be driven by the option serial 
> driver (drivers/usb/serial/option.c). I did not check, which other files are 
> required to create a working driver thou.
> 
> I will try to expand `usb_terminal` to support both types of serial ports.

On second thought: The 'usb_terminal' is a server. What you would need is a 
terminal client that writes received data from the UART to the terminal session 
and that writes received data from the terminal session to the UART. You can 
take 'ns16550' in the allwinner repo as a reference (main.cc).

As an afterthought: In case you need data connectivity only, you could try 
setting the modem into MBIM mode, since we have MBIM support in Genode's 'world' 
repo [1] and the USB-modem driver for that is already in place [2]:

The AT command to change the mode to MBIM is

! AT+QCFG="usbnet",2

and reboot the modem via

! AT+CFUN=1,1

in order to activate the change, which is permanent until you change the mode to 
something else.

Next you could try out the ''mbimcli.run' [3] script adjusting the following 
line to the correct values from your provider:

! <network apn="internet.eplus.de" user="eplus" password="eplus" pin="XXXX"/>

*pin is the pin of your SIM card

If you are lucky this might work out of the box, but it is uncharted territory 
so far ;) We have only tested this with Huawei's ME906s and Fibocom's 
L830-EB-00. It would be interesting if this works because MBIM is a generic 
protocol that should work with all MBIM supporting modems.

Cheers and let me know about the outcome,

Sebastian

[1] https://github.com/genodelabs/genode-world/tree/master/src/app/mbimcli
[2] 
https://github.com/genodelabs/genode/tree/master/repos/dde_linux/src/drivers/usb_modem 

[3] https://github.com/genodelabs/genode-world/blob/master/run/mbimcli.run

-- 
Sebastian Sumpf
Genode Labs

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