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

[Krzysztof Kozlowski <krzk@kernel.org>]

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@oss.qualcomm.com/
> 
> 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.

> 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@linaro.org/
> 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.

> 
> 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.

Best regards,
Krzysztof