Re: Add Support for Sierra MC73xx

[Martin Chaplet <m.chaplet@kerlink.fr>]

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Hi Denis

On 29/04/2016 18:01, Denis Kenzior wrote:
> Hi Martin,
>
> On 04/29/2016 10:53 AM, Martin Chaplet wrote:
>>
>>
>> On 29/04/2016 17:44, Denis Kenzior wrote:
>>>
>>>>
>>>> This card is mainly QMI but also have Diag, NMEA and AT interfaces
>>>> (ttyUSB). I think that's why he did it in setup_sierra.
>>>>
>>>
>>> What is the AT interface capable of?  Can this modem be driven using
>>> AT commands instead?  Would certainly be easier to debug.
>>
>> All main commands are available ( ETSI) but I don't think PPP can be
>> used.
>> Additionnaly, it's a 4G modem, using PPP layer instead QMI will reduce
>> performances, isn't it ?
>
> You definitely don't want ppp.  Besides, ppp requires 2 functional AT
> ports, and it looks like this card has just one.
>
> Does Sierra provide network management via vendor AT commands?

As the modem support FOTA auto update feature, I assume they must exist.
I will take a look at the manuals.

>
>>
>> Do you mean I can use an "hybrid" mode using modem management through AT
>> and network through QMI ?
>
> This is quite possible as well.
>
>>
>>>
>>>>>
>>>>> Your modem doesn't seem to want to read anything from the SIM.  So
>>>>> that is why your gprs isn't showing up.
>>>>>
>>>>> Do you have a SIM in there or a PIN set?
>>>>
>>>>
>>>> OK, so I understand that Data feature is detected by scanning SIM
>>>> capabilities + chip capabilities (UMTS, LTE, ...)
>>>> Am I right ?
>>>
>>> Sort of.  oFono is a full telephony stack, so we expect the basics to
>>> be provided.  IMSI availability tells us that the SIM has been
>>> initialized to the point that it is useable.  E.g. PIN has been
>>> unlocked/entered.
>>>
>> OK, I see.
>>>>
>>>> My SIM doesn't have PIN and I can use Standard QMI tools (libqmi) to
>>>> bring up a connection.
>>>> I will so investigate around SIM QMI requests / replies.
>>>
>>> Are sim operations supported / working on this modem with libqmi?
>> Yes.
>> Please find few tests below
>>
>> $ qmicli -d /dev/cdc-wdm0 --dms-uim-get-imsi
>> [/dev/cdc-wdm0] UIM IMSI retrieved:
>>          IMSI: '208103790757141'
>>
>> $ qmicli -d /dev/cdc-wdm0 --dms-uim-get-state
>> [/dev/cdc-wdm0] UIM state retrieved:
>>          State: 'initialization-completed'
>>
>> $ qmicli -d /dev/cdc-wdm0 --dms-uim-get-pin-status
>> [/dev/cdc-wdm0] PIN status retrieved successfully
>> [/dev/cdc-wdm0] PIN1:
>>          Status: disabled
>>          Verify: 3
>>          Unblock: 10
>> [/dev/cdc-wdm0] PIN2:
>>          Status: enabled-not-verified
>>          Verify: 2
>>          Unblock: 10
>>
>
> This looks to be in agreement with what oFono is obtaining from the
> drivers/qmimodem/sim.c driver.  However, qmi_read_transparent and
> qmi_read_record don't seem to be reporting proper values.
>
> Does libqmi actually have low-level sim read capability?

Yes, it seems so :

$ qmicli -d /dev/cdc-wdm0 --help-uim
UIM options
 
--uim-read-transparent=[0xNNNN,0xNNNN,...]                                           
Read a transparent file given the file path
 
--uim-get-file-attributes=[0xNNNN,0xNNNN,...]                                        
Get the attributes of a given file
 
--uim-get-card-status                                                                
Get card status
 
--uim-reset                                                                          
Reset the service state
  --uim-noop   

I'm not used to QMI but I will try to compare libqmi and ofono's
read_transparent implementations.

>
> Another thing to try would be to implement read_imsi() method for
> drivers/qmimodem/sim.c.  This should get you to the point where gprs
> is initialized even if all low-level reads from the SIM fail.

It seems a great idea.

Thanks a lot for you help Denis,

Best regards,

Martin


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