Re: The way to install proper driver for 3G dongle in oFono

[Guillaume Zajac <guillaume.zajac@linux.intel.com>]

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Hi Marcel,

On 04/01/2012 17:12, Marcel Holtmann wrote:
> Hi Guillaume,
>
>>>>>>>>>> and what about the case when the SIM card is present, but PIN locked?
>>>>>>>>>>
>>>>>>>>>>> According to the result, it might be interesting to send ATI when the
>>>>>>>>>>> constructor plugin is probe by oFono.
>>>>>>>>>>> Thus with +GCAP info we can decide which driver to use.
>>>>>>>>>> Is sending +GCAP after ATI really a standard? Have we tried anything
>>>>>>>>>> else besides Huawei or ZTE?
>>>>>>>>> I tried with more dongles from different vendors, as attached table.
>>>>>>>>> The scenarios include:
>>>>>>>>> With valid sim card, sim card PIN locked, no sim card, sim card locked.
>>>>>>>>> N(ROM) in table indicates the SIM in ROM already.
>>>>>>>>> ATI command can always return GCAP content in all tests.
>>>>>>>> and what about other manufactures other than Huawei, ZTE and SpeedUp?
>>>>>>>> What about Sierra, Ericsson etc.?
>>>>>>> Just checked Dell 5530 with Ericsson module,
>>>>>>> With SIM card or not, at+gcap can return +GCAP:+CGSM, +DS
>>>>>>> But the ATI only returns: D5530
>>>>>> I think it is clear that we need to do our homework here and properly
>>>>>> document the different manufacturers. Someone sending patches for our
>>>>>> doc/ directory?
>>>>> There're many vendors of 3G dongle..
>>>>> Huawei, ZTE (they share 70%+ of global market), Longcheer, Haier, Sentar, Viton, D-link, SCV, BandRich, Strongrising.. (more than 30 vendors in China)
>>>>> Sierra, Sony-Ericsson, Option, Novatel, Alcatel, Samsung, LG, AnyData, C-motech, Micromax...
>>>>> We can try with them step by step, but can we work out the 2 biggest firstly?
>>>>> Looks ATI command can work for both Huawei and ZTE dongles.
>>>>>
>>>> I agree here, the work to be done over all manufacturers will be
>>>> fastidious and might require a lot of dongles that we don't have currently.
>>>> Maybe we could do as Ying An proposed as we are sure ATI works for
>>>> Huawei and ZTE (at least the ones we have).
>>>> However, conerning ZTE I haven't seen any CDMA dongle for the moment.
>>>>
>>>>>>>>>> Also you do realize that the GAtChat object and thus the file descriptor
>>>>>>>>>> is owned by the modem plugin. The plugin itself is the only one that
>>>>>>>>>> should do any kind of IO.
>>>>>>>>>>
>>>>>>>>>> So if we require to run ATI first to identify if we are GSM or CDMA,
>>>>>>>>>> then this is a per modem manufacture specific detail. And we rather add
>>>>>>>>>> a helper function like we did for CPIN polling that makes this easier.
>>>>>>>>>>
>>>>>>>>> In current code the 'driver' is hardcoded by comparing with vendor_list[].
>>>>>>>>> So if it possible to break the step into several:
>>>>>>>>> vendor_list[] in udevng just cares about vendor - by comparing vendor ID
>>>>>> only,
>>>>>>>>> and add all possible drivers according to that vendor - (for example add
>>>>>>>>> WCDMA, CDMA2k, TDSCDMA, LTE ...drivers if Huawei dongle is plugged
>>>>>> in),
>>>>>>>>> and the probe interface in each driver does real probe work as to issue
>>>>>>>>> ATI command to ensure only correct driver will be loaded?
>>>>>>>> As I said before, the only time IO can be started is when the ->enable()
>>>>>>>> callback of the modem plugin is called. Not a second earlier.
>>>>>>> But if done after enable() called, from semantic aspect the correct driver has
>>>>>> been
>>>>>>> chosen. Indeed the probe() interface in each driver is not doing something to
>>>>>> probe,
>>>>>>> then can the work be done in probe()? As set CFUN=1 then doing some dongle
>>>>>> vendor
>>>>>>> specific work as query model or network mode by ATI, AT+GCAP command,
>>>>>> etc..? After
>>>>>>> that disable dongle when quit probe()?
>>>>>> The probe() callback is for accepting the driver and allocating required
>>>>>> local data structures. It is not for IO. And as you can see it has no
>>>>>> callback handling like enable() with set_powered().
>>>>>>
>>>>>> As I said before, no AT commands before enable() has been called. That
>>>>>> is how it is suppose to be. We are not changing this.
>>>> First, ATI command is working without sending AT+CFUN=1, we could keep
>>>> CFUN=1 into enable() as we do some vendor/modem type specific job there.
>>>>
>>>> Then vendor plugin can be chosen using udevng using Vendor ID, however
>>>> driver type (CDMA/GSM) can't lie on the Product ID. So it will be hard
>>>> to chose the right vendor plugin with right type.
>>>> And if we can't send AT command before enable() time we will face to bag
>>>> end e.g. :
>>>> For huawei plugin we send GSM specific AT command (AT^RFSWITCH) during
>>>> the enable() time.
>>>> We are also querying the sim state using polling mechanism that might
>>>> fail for CDMA modems that is not using SIM.
>>>> What would you suggest here?
>>> as I said before, no AT commands before ->enable() callback from the
>>> core.
>>>
>>> The callback ->probe() is for accepting the modem driver binding and
>>> allocating modem specific data memory. The callback ->remove() is for
>>> cleanup.
>>>
>>> The callbacks ->enable(), ->disable() and ->set_online() are the only IO
>>> entry points for every modem driver. And we need to keep it like this.
>> Ok, so I suggest to do the ATI at the very beginning of ->enable() callback.
> the first command has to be always ATE0 +CMEE=1 since otherwise you a)
> can not use the permissive syntax parser and b) your error values will
> be useless.
>
> But yes, after that it is fine to send ATI.
>

Ok

>> Then depending on the ATI answer:
>>       - tag the huawei modem data with GSM / CDMA type.
>>       - send the GSM / CDMA specific AT commands followed by AT+CFUN=1.
> What different commands depending on GSM or CDMA do you actually have?
>
> The AT^RFSWITCH=? is exactly designed to handle if that command is
> supported or not. There are plenty of GSM versions of the Huawei that do
> not support AT^RFSWITCH. You do need to know if this is supported or
> not.

I see, so we can send AT^RFSWITCH for both type. If it is not supported, 
it will be ignored using terminator and then use
default AT+CFUN=5.

> Also we do not send AT+CFUN=1 in ->enable() callback. We bring the modem
> into offline mode. The only time you send AT+CFUN=1 is if you have
> hardware that does not support online/offline distinction. So if this is
> true for Huawei CDMA modems, then the obvious questions is why that is
> the case? Or is this a bug with our CDMA support not supporting offline
> mode.
>

For the moment, CDMA modems are not using ->set_online() callback (it is 
automatically set online into modem.c).
We will have to make some test to check AT+CFUN=5 is working on CDMA modems.

>> We should not longer make the difference between "huawei" and
>> "huaweicdma" into udevng.
>> It also means there is one unified plugin.
> That is totally fine.
>
>>> The callback ->pre_sim(), ->post_sim() and ->post_online() are the entry
>>> points for selecting atom drivers. These are not allowed to do IO
>>> directly either.
>> Here, using the tagged type, the plugin can decide which driver to use
>> to create atom.
>> Does it sound ok to you?
> Fine with me.
>
> Regards
>
> Marcel

Kind regards,
Guillaume