[PATCH] huawei: fix ^ICCID parsing

[Ben Chan]

I tried a Huawei modem with Qualcomm chipset, and ^ICCID doesn't swap
the digits.  Perhaps newer models have this behavior.

On Wed, Sep 25, 2013 at 9:36 AM, Dan Williams <dcbw at redhat.com> wrote:
> On Wed, 2013-09-25 at 09:08 -0700, Ben Chan wrote:
>> On Wed, Sep 25, 2013 at 7:09 AM, Aleksander Morgado
>> <aleksander at lanedo.com> wrote:
>> > On 09/25/2013 02:56 PM, Dan Williams wrote:
>> >>> Seems like some modems swap digits in ^ICCID response and some don't.
>> >>> > We may need to compute the check digit to determine which format to
>> >>> > use.
>> >> Ben and I talked about this yesterday; every Huawei modem I have, from
>> >> the E160g (really old) to a new E397 (recent) swaps the digits in the
>> >> ^ICCID response.  These are all Qualcomm-based devices.
>> >>
>> >> But I think the E3xxx devices are HiSilicon-based devices, not Qualcomm
>> >> ones.  Which would mean completely different firmware, and probably a
>> >> completely different team, which probably interpreted the ICCID command
>> >> specs completely differently (if there were any).  Not sure about the
>> >> MU736 though.
>> >
>> > Using the checksum in the ICCID would be a good way, and easy to
>> > implement I guess. Another option would be to just check the first two
>> > digits to see if they're 89 or 98 :) '89' is the ISO 7812 Major Industry
>> > Identifier for telecomm purposes. Have you guys ever seen a ICCID in a
>> > SIM card not starting with 89?
>>
>> Dan, that's an interesting observation. All the modems I've tested so
>> far are non-Qualcomm based. I'll test a Qualcomm-based modem today.
>>
>> Regarding the check digit approach, it may depend on the SIM issuers.
>> Some ICCIDs have 19+1 digits or 18+1 digits. Some may not have the
>> check digit?
>
> As far as I know, they have to have the check digit...
>
> But here's why we want ^ICCID:
>
> at+CRSM=176,12258,0,0,10
> +CME ERROR: SIM PIN required
> at^iccid?
> ^iccid: "9810xxxxxxxxxxxxxxxx"
> OK
>
> Not having to unlock the modem before getting the ICCID means that
> userspace can use the SimIdentifier property to retrieve the right PIN
> for auto-unlock or other operations.
>
> Dan
>