Re: [PATCH v2 0/3] Add TPM support via Qualcomm TEE TPM TA

[Kuldeep Singh <kuldeep.singh@oss.qualcomm.com>]

On 01-10-2026 11:20, zeroknots wrote:
> Hi Kuldeep,
> 
> A data point from retail hardware, in case it is useful for this
> series: on an ASUS Zenbook A14 UX3407NA (Glymur, X2E-88-100, BIOS
> UX3407NA.315) the TPM TA is not reachable as QTEE service 81, but it
> is present as the QSEECOM application "qcom.tz.tpm".

Thanks for reaching out, Kindly check below.

> With the qcomtee driver on a 7.3-rc3 based kernel, QTEE reports
> version 5.2.0, and service discovery finds neither 81 (TPM) nor 413
> (UEFI secure app). On the same boot, qseecom (version 0x1402000) works
> and backs efivars through "qcom.tz.uefisecapp" (app id 7). An app-id
> lookup for "qcom.tz.tpm" returns app id 1; a made-up name returns
> -ENOENT.
> 
> The Windows driver for this machine agrees: QcTrEE8480.inf configures
> the TPM service with AppName="qcom.tz.tpm", SecureApp=1, LoadApp=0
> (preloaded by firmware). The EFI configuration table carries the
> TPMEventLog and TPMFinalLog entries, so the firmware TPM is active.
> 
> Through that app, using a QSEECOM transport (based on Xilin Wu's
> out-of-tree SC8280XP driver: QUERY_INFO_2 / SEND_COMMAND with a
> CRB-style control area, here at 0x81d10000), /dev/tpm0 works: TPM 2.0,
> manufacturer QCOM, vendor string "xCG fTPM", firmware 0x40000, real
> PCR 0-7 values, GetRandom, ECC and RSA-2048 primaries, sign and
> verify, and a sealed object that persists across reboots.
> 
> So, as far as I can tell, retail Glymur laptops may ship firmware on
> which this driver finds no TPM, while the same TA is available over
> QSEECOM.
> 
> The same applies to the prerequisite series that moves uefisecapp to
> QCOMTEE [1]: on this firmware service 413 is absent and EFI variables
> work only through the QSEECOM uefisecapp. If the QSEECOM path were
> dropped for Glymur, efivars would stop working on this machine, so it
> would be good to keep it as a fallback when the QTEE service is not
> found.
> 
> Two questions:
> 
>  - Is service 81 expected to appear on retail firmware through an
>    update, or is it specific to the CRD firmware?

Yes, there's spinor update(bootfw2.mbn) needed which is in progress to
publish as QTEE side changes were already merged long back.
Roughly it takes ~1month(ideal scenario) to get firmware changes
available but somehow it's taking more this time.

I think i should have captured this dependency info in my series cover
letter to avoid any confusion.

With the changes, service uid 81 will be available and won't see qcomtee
driver issue log there.

>  - Would you consider a QSEECOM-based path for such firmware? I am
>    happy to test this series, or any other service UID you would like
>    checked, on this machine, and to share the transport code.
> 

Qseecom-based firmware path is not recommend approach as it's not
generic and less scalable leaving less room for expanding featuresets.
qcomtee uses mink-ipc based model which does all interaction with TA
with just 2 scm calls and is very much scalable compared to qseecom.

So, we are planning to use mink-ipc based qcomtee path only and I'll
drop an update once QTEE firmware changes are available in meta builds.
I'd be happy you to try it out and give any suggestions!

-- 
Regards
Kuldeep