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

[Harshal Dev]

Hi Krzysztof,

On 12/2/2025 3:13 PM, Krzysztof Kozlowski wrote:
> On 02/12/2025 10:37, Harshal Dev wrote:
>> Enable config for the QCOMTEE driver to facilitate communication with the
>> Qualcomm Trusted Execution Environment (QTEE) on Qualcomm platforms.
> 
> Which platforms use it?

The Qualcomm Trusted Execution Environment (QTEE) firmware is available on all
Qualcomm platforms. However, certain platforms like db410c (APQ8016), where QTEE
does not support Object-IPC (the communication protocol implemented by QCOMTEE driver)
a graceful -EIO is returned by qcom_scm_qtee_init() which is in-charge of dynamically
registering the QCOMTEE driver as a platform driver during qcom_scm_probe().
More details available here: https://lore.kernel.org/op-tee/20250820-qcom-tee-using-tee-ss-without-mem-obj-v8-0-7066680f138a@xxxxxxxxxxxxxxxx/T/#m1eba97cb921c958034ffe7e2bfb776177ba48eb6

And so, the QCOMTEE driver can be safely enabled on all Qualcomm platforms regardless
of QTEE firmware version.

> Why this cannot be a module?

Upon a bit of reflection, I have realized that it is completely fine to have this driver
built as an in-tree module. I have also validated that this presents no issues during
loading/unloading of the driver.

I will send a new patch and update the CONFIG_QCOMTEE flag to m.

Regards,
Harshal

>
>>
>> Signed-off-by: Harshal Dev <harshal.dev@xxxxxxxxxxxxxxxx>
>> ---
>>  arch/arm64/configs/defconfig | 1 +
>>  1 file changed, 1 insertion(+)
>>
> Best regards,
> Krzysztof