Re: [PATCH v2] arm64: defconfig: Enable QCOMTEE for Qualcomm SoCs

[Harshal Dev]

Hi Krzysztof,

On 12/5/2025 4:42 PM, Krzysztof Kozlowski wrote:
> On 05/12/2025 11:58, Harshal Dev wrote:
>> Hi Krzysztof
>>
>> On 12/5/2025 1:45 PM, Krzysztof Kozlowski wrote:
>>> On 05/12/2025 09:12, Harshal Dev wrote:
>>>> Enable config 'm' for the QCOMTEE driver to facilitate communication with
>>>> the Qualcomm Trusted Execution Environment (QTEE) on Qualcomm platforms.
>>>
>>> I can do it forever, but next time I will just NAK.
>>>
>>> Which platforms need this? Which platforms use this?
>>
>> Looks like I misunderstood your comment on the last patch regarding Qualcomm
>> platform support for this driver as more of a generic question instead of being
>> a hard request to update the commit message. 
>> https://lore.kernel.org/all/f20833a4-1571-41f8-875a-d27086be3090@xxxxxxxxxxxxxxxx/
>>
>> I will take care of this now, however I am still a bit confused regarding how many
>> platforms should I explicitly list out in the commit message. I took reference of
> 
> Just mention which UPSTREAM boards (which you called Qualcomm platforms)
> use this driver. It's enough to mention one, for justification of
> commit. You can mention two as well. Or three.
>

Thanks for this clarification Krzysztof, since the driver is related to SoC firmware and
not on the board, I will mention SM8650+ as the supported SoCs since we began enabling
the driver from that chip on-wards. I hope this reasoning is fine.

>> these below patches merged earlier in the defconfig for enabling the QCE crypto block driver,
>> Qualcomm Watchdog driver and Qualcomm RNG driver. And I did not see them listing out
>> any specific Qualcomm platforms which need/use these drivers. I understand that this is
>> because the drivers provide generic functionality applicable on all Qualcomm SoCs.
>> https://lore.kernel.org/all/20220921045602.1462007-5-bhupesh.sharma@xxxxxxxxxx/
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f27dbbda5900c20e07418c6893ca6e95b634f4ff
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2774e558151a6e325e1f9f278722479601319f78
> 
> :) unfortunately all poor examples. And from 2019! You can find many
> poor examples in the kernel - in commit msgs or code. You can find many
> obsolete drivers written in old, not updated style. These are not
> examples to be based on.
> 
> Usually it is the best to take LATEST reviewed code, not something 6
> years old, so the process would be:
> 
> tig -- arch/arm64/configs/defconfig
> /Qualcomm
> (or whatever search query you want)
> Which would give you commit c5d02bbaa217b2454ba1ce7528113aa2ecf14f3c
> from June for example. It even caries two review tags.
>

I appreciate you taking the time to provide this advice. Acknowledged. :)

>>
>> Similarly, all Qualcomm SoCs have ARM TrustZone support with a QTEE firmware OS running.
>> The version of the firmware might differ, but it is always there, and so the QCOMTEE driver is
>> applicable to all Qualcomm SoCs just like the Watchdog or RNG driver.
> 
> You can say that all Qualcomm platforms use it... but I would challange
> it, because not all platforms use watchdog or RNG.
>

Sure, let's not do a 1-1 comparison between watchdog/RNG anc QCOMTEE.

Regards,
Harshal
 
> Best regards,
> Krzysztof