GNSS support for Qualcomm PCIe modem device

GNSS support for Qualcomm PCIe modem device

[Slark Xiao]

Hi Sergey, Muhammad,
This is Slark. We have a discussion about the feature of GNSS/NMEA over QC PCIe modem 
device since 2024/12.May I know if we have any progress on this feature? 

It's really a common requirement for modem device since we have received some complaint
from our customer. Please help provide your advice.


Thank you in advance!

Re: GNSS support for Qualcomm PCIe modem device

[Muhammad Nuzaihan]

Hi Slark,

I just implemented it in the wwan subsystem since it works for me (even 
without flow control). I wanted to port it to use GPS subsystem, 
however, debugging in GPS subsystem is too troublesome, especially when 
the driver crashes.

Unless i can have some VM with direct access to the Quectel hardware so 
i don't need to keep rebooting my machine if it crashes.

For now, i am getting GNSS/NMEA data from Quectel with MHI wwan 
modifications.

Regards,
Zaihan


On Thu, Apr 3 2025 at 04:02:01 PM +0800, Muhammad Nuzaihan 
<zaihan@unrealasia.net> wrote:
> Hi Slark,
> 
> I just implemented it in the wwan subsystem since it works for me 
> (even without flow control). I wanted to port it to use GPS 
> subsystem, however, debugging in GPS subsystem is too troublesome, 
> especially when the driver crashes.
> 
> Unless i can have some VM with direct access to the Quectel hardware 
> so i don't need to keep rebooting my machine if it crashes.
> 
> For now, i am getting GNSS/NMEA data from Quectel with MHI wwan 
> modifications.
> 
> Regards,
> Zaihan
> 
> On Thu, Apr 3 2025 at 02:06:52 PM +0800, Slark Xiao 
> <slark_xiao@163.com> wrote:
>> 
>> Hi Sergey, Muhammad,
>> This is Slark. We have a discussion about the feature of GNSS/NMEA 
>> over QC PCIe modem
>> device since 2024/12.May I know if we have any progress on this 
>> feature?
>> 
>> It's really a common requirement for modem device since we have 
>> received some complaint
>> from our customer. Please help provide your advice.
>> 
>> 
>> Thank you in advance!
>> 

Re: GNSS support for Qualcomm PCIe modem device

[Sergey Ryazanov]

Hi Slark, Zaihan,

Zaihn, congratulations with the progress, curious to see the result.

Slark, thank you for remind me. It's a good moment. Lets see how we can 
prototype it. Will try to do it this weekend and send some RFC next week.

On 03.04.2025 11:42, Muhammad Nuzaihan wrote:
> Hi Slark,
> 
> I just implemented it in the wwan subsystem since it works for me (even 
> without flow control). I wanted to port it to use GPS subsystem, 
> however, debugging in GPS subsystem is too troublesome, especially when 
> the driver crashes.
> 
> Unless i can have some VM with direct access to the Quectel hardware so 
> i don't need to keep rebooting my machine if it crashes.
> 
> For now, i am getting GNSS/NMEA data from Quectel with MHI wwan 
> modifications.
> 
> Regards,
> Zaihan
> 
> 
> On Thu, Apr 3 2025 at 04:02:01 PM +0800, Muhammad Nuzaihan 
> <zaihan@unrealasia.net> wrote:
>> Hi Slark,
>>
>> I just implemented it in the wwan subsystem since it works for me 
>> (even without flow control). I wanted to port it to use GPS subsystem, 
>> however, debugging in GPS subsystem is too troublesome, especially 
>> when the driver crashes.
>>
>> Unless i can have some VM with direct access to the Quectel hardware 
>> so i don't need to keep rebooting my machine if it crashes.
>>
>> For now, i am getting GNSS/NMEA data from Quectel with MHI wwan 
>> modifications.
>>
>> Regards,
>> Zaihan
>>
>> On Thu, Apr 3 2025 at 02:06:52 PM +0800, Slark Xiao 
>> <slark_xiao@163.com> wrote:
>>>
>>> Hi Sergey, Muhammad,
>>> This is Slark. We have a discussion about the feature of GNSS/NMEA 
>>> over QC PCIe modem
>>> device since 2024/12.May I know if we have any progress on this feature?
>>>
>>> It's really a common requirement for modem device since we have 
>>> received some complaint
>>> from our customer. Please help provide your advice.

--
Sergey

Re: GNSS support for Qualcomm PCIe modem device

[Muhammad Nuzaihan]

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Hi Sergey, Slark,

Using wwan subsystem and it works without issues, maybe i might miss
something, perhaps the flow control but i never have any problems even
without flow control.

I am using gpsd + cgps and xgps with a small modification to Linux
kernel's wwan subsystem in the kernel to get NMEA data.

I had posted the patch previously and i can post the patch again if you like.

Attached in this email is the screenshot of cgps + gpsd.

Maybe it should be in GPS subsystem but it's working for me even using
wwan subsystem for months now.

Regards,
Zaihan
On Fri, Apr 4, 2025 at 5:46 AM Sergey Ryazanov <ryazanov.s.a@gmail.com> wrote:
>
> Hi Slark, Zaihan,
>
> Zaihn, congratulations with the progress, curious to see the result.
>
> Slark, thank you for remind me. It's a good moment. Lets see how we can
> prototype it. Will try to do it this weekend and send some RFC next week.
>
> On 03.04.2025 11:42, Muhammad Nuzaihan wrote:
> > Hi Slark,
> >
> > I just implemented it in the wwan subsystem since it works for me (even
> > without flow control). I wanted to port it to use GPS subsystem,
> > however, debugging in GPS subsystem is too troublesome, especially when
> > the driver crashes.
> >
> > Unless i can have some VM with direct access to the Quectel hardware so
> > i don't need to keep rebooting my machine if it crashes.
> >
> > For now, i am getting GNSS/NMEA data from Quectel with MHI wwan
> > modifications.
> >
> > Regards,
> > Zaihan
> >
> >
> > On Thu, Apr 3 2025 at 04:02:01 PM +0800, Muhammad Nuzaihan
> > <zaihan@unrealasia.net> wrote:
> >> Hi Slark,
> >>
> >> I just implemented it in the wwan subsystem since it works for me
> >> (even without flow control). I wanted to port it to use GPS subsystem,
> >> however, debugging in GPS subsystem is too troublesome, especially
> >> when the driver crashes.
> >>
> >> Unless i can have some VM with direct access to the Quectel hardware
> >> so i don't need to keep rebooting my machine if it crashes.
> >>
> >> For now, i am getting GNSS/NMEA data from Quectel with MHI wwan
> >> modifications.
> >>
> >> Regards,
> >> Zaihan
> >>
> >> On Thu, Apr 3 2025 at 02:06:52 PM +0800, Slark Xiao
> >> <slark_xiao@163.com> wrote:
> >>>
> >>> Hi Sergey, Muhammad,
> >>> This is Slark. We have a discussion about the feature of GNSS/NMEA
> >>> over QC PCIe modem
> >>> device since 2024/12.May I know if we have any progress on this feature?
> >>>
> >>> It's really a common requirement for modem device since we have
> >>> received some complaint
> >>> from our customer. Please help provide your advice.
>
> --
> Sergey

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Re: GNSS support for Qualcomm PCIe modem device

[Loic Poulain]

Hi Zhaihan, Sergey.

On Fri, Apr 4, 2025 at 7:42 AM Muhammad Nuzaihan <zaihan@unrealasia.net> wrote:
>
> Hi Sergey, Slark,
>
> Using wwan subsystem and it works without issues, maybe i might miss
> something, perhaps the flow control but i never have any problems even
> without flow control.
>
> I am using gpsd + cgps and xgps with a small modification to Linux
> kernel's wwan subsystem in the kernel to get NMEA data.
>
> I had posted the patch previously and i can post the patch again if you like.
>
> Attached in this email is the screenshot of cgps + gpsd.
>
> Maybe it should be in GPS subsystem but it's working for me even using
> wwan subsystem for months now.

Yes, I would strongly recommend doing the extra step of making it
registered to the GNSS subsystem so that device is exposed with the
correct class.
From WWAN driver perspective, it will not change anything, as we could
have the WWAN framework handling this properly (bridging to gnss
intead of exposing the port as wwan character device).
Sergey, is it your plan?

Regards,
Loic

Re: GNSS support for Qualcomm PCIe modem device

[Sergey Ryazanov]

On April 8, 2025 12:13:17 PM GMT+03:00, Loic Poulain <loic.poulain@oss.qualcomm.com> wrote:
>Hi Zhaihan, Sergey.
>
>On Fri, Apr 4, 2025 at 7:42 AM Muhammad Nuzaihan <zaihan@unrealasia.net> wrote:
>>
>> Hi Sergey, Slark,
>>
>> Using wwan subsystem and it works without issues, maybe i might miss
>> something, perhaps the flow control but i never have any problems even
>> without flow control.
>>
>> I am using gpsd + cgps and xgps with a small modification to Linux
>> kernel's wwan subsystem in the kernel to get NMEA data.
>>
>> I had posted the patch previously and i can post the patch again if you like.
>>
>> Attached in this email is the screenshot of cgps + gpsd.
>>
>> Maybe it should be in GPS subsystem but it's working for me even using
>> wwan subsystem for months now.
>
>Yes, I would strongly recommend doing the extra step of making it
>registered to the GNSS subsystem so that device is exposed with the
>correct class.
>From WWAN driver perspective, it will not change anything, as we could
>have the WWAN framework handling this properly (bridging to gnss
>intead of exposing the port as wwan character device).
>Sergey, is it your plan?

Yep. I made the prototype exactly in this way. So a modem driver should not care about the port type. Just call WWAN core and it will do the job for the driver.

The prototype is done. Needs some polishing, proper description, and probably, today night I'm going to publish  the RFC.
Hi Loic,

Re: GNSS support for Qualcomm PCIe modem device

[Muhammad Nuzaihan]

Hi Loic, Sergey,

Thank you Sergey for your time for the prototype.

Looking forward for the code (and coding help if necessary) and help
to test it on my machine.

Zaihan

On Tue, Apr 8, 2025 at 6:27 PM Sergey Ryazanov <ryazanov.s.a@gmail.com> wrote:
>
> On April 8, 2025 12:13:17 PM GMT+03:00, Loic Poulain <loic.poulain@oss.qualcomm.com> wrote:
> >Hi Zhaihan, Sergey.
> >
> >On Fri, Apr 4, 2025 at 7:42 AM Muhammad Nuzaihan <zaihan@unrealasia.net> wrote:
> >>
> >> Hi Sergey, Slark,
> >>
> >> Using wwan subsystem and it works without issues, maybe i might miss
> >> something, perhaps the flow control but i never have any problems even
> >> without flow control.
> >>
> >> I am using gpsd + cgps and xgps with a small modification to Linux
> >> kernel's wwan subsystem in the kernel to get NMEA data.
> >>
> >> I had posted the patch previously and i can post the patch again if you like.
> >>
> >> Attached in this email is the screenshot of cgps + gpsd.
> >>
> >> Maybe it should be in GPS subsystem but it's working for me even using
> >> wwan subsystem for months now.
> >
> >Yes, I would strongly recommend doing the extra step of making it
> >registered to the GNSS subsystem so that device is exposed with the
> >correct class.
> >From WWAN driver perspective, it will not change anything, as we could
> >have the WWAN framework handling this properly (bridging to gnss
> >intead of exposing the port as wwan character device).
> >Sergey, is it your plan?
>
> Yep. I made the prototype exactly in this way. So a modem driver should not care about the port type. Just call WWAN core and it will do the job for the driver.
>
> The prototype is done. Needs some polishing, proper description, and probably, today night I'm going to publish  the RFC.
> Hi Loic,