CDMA modems and oFono

Hi Denis,

I have sent some patches concerning UIM for CDMA modem but I think I am missing something around modem.c so you can give them up :)

For the moment, "modem.c" is designed for GSM modem, SIM atom is watched to add a state watch to make modem progressing into pre_sim post_sim online states etc...
However in the case of a CDMA modem we will have to watch another type of atom (UIM for instance) and make the modem progressing into the following states: pre_uim post_uim etc...

So what would you suggest to introduce CDMA modem into oFono? Should we create another src/cdma_modem.c with its own watches, states and cdma_atoms?
Or should we keep the current naming (e.g. pre_sim post_sim etc...) and change current api to create cdma modem?
Something like: ofono_modem_create(cdma=true/false) that is called from udevng. Then this new modem would be tagged as cdma and we would look for UIM atom intstead of SIM atom in case of cdma modem.

What do you think about it?

Kind regards,
Guillaume

Hi Guillaume,

I think we need to understand in what ways UIM and SIMs are different. E.g. is it a manner of different EFs being present and their read order or something more fundamental. To my understanding 3GPP just recycled the SIM specs from ETSI, so the fundamentals should be the same.

I think we need to learn a bit more about UIMs first. Ideally I'd like to handle both in the sim atom if possible. At least that would make sense from dual-mode device standpoint (e.g. something than can use CDMA and LTE)

Regards,
-Denis

Hi Denis,

Looking to the R-UIM 3GPP2 specification (C.S0023), we can understand indeed that R-UIM can be considered as an extension of SIM. In practice, we can retrieve the same information as for SIM, based obviously on different file ids (Emergency codes, preferred language, service table, etc...)

So far, we could imagine to extend the SIM atom to support also R-UIM architecture but what could be the purpose of this extension? Here, the UIM atom is introduced originally to collect a subscriber identifier (MIN or True IMSI) in order to identify uniquely the cdma-connman interface.
But you seems to look for a more global solution. Are we looking to support also cdma for voice? cdma for card application tool kit?

Now, if we just need to collect this CDMA subscriber identifier, I think also excessive to introduce a specific atom for that.

Regards,

Philippe.

Hi Philippe,

Of course we do. We want a fully functional CDMA stack at some point, with support for UIM, STK, voice, etc. This is the reason why we defined the voice APIs for CDMA so early.

While I'm not completely certain about using a unified Sim atom (CDMA experts feel free to chime in), I think fundamentally CDMA/GSM are very similar. As you mention it is a matter of reading different EFs, while CHV/PIN handling, BDN, FDN, etc are the same.

So ideally I'd like to figure out what parts are common, what parts are different and how do these parts overlap. For example, the EFecc file is read by the voicecall atom in GSM. The CDMA equivalent EFecc can be read by the cdma-voicecall atom, hence there's no real work to unify these.

If it is not infeasible to unify these, then that is what I would like to do. Same goes for other atoms that might be similar enough, e.g. Phonebook.

Sure, but unfortunately that is not the only thing you need. Think about pin entry, puk entry, pin lock, unlock, retries, pin2 handling. Maybe you can get by without these, but then the user has to know all of these details; definitely not an attribute of a quality product ;)

Regards,
-Denis