Re: [PATCH v2 4/6] tee: optee: Register TEE devices on the platform bus

[Harshal Dev <harshal.dev@oss.qualcomm.com>]

Hi,

On 11-11-2026 08:27 pm, Harshal Dev wrote:
> + op-tee@lists.trustedfirmware.org, Jens Wiklander <jens.wiklander@oss.qualcomm.com>
> 
> On 11-11-2026 07:47 pm, Harshal Dev wrote:
>> The Qualcomm Inline Crypto Engine (ICE) driver is an independent platform
>> driver which polls on availability of a TEE interface (SCM driver) before
>> checking if the ICE secure service is supported by QTEE by querying the
>> qcom_scm_ice_available() API.
>>
>> The TEE subsystem currently does not provide any way to notify regarding
>> the availability of a TEE interface, i.e. whether QCOMTEE or OPTEE have
>> probed. And so when migrating to the TEE subsystem via an ICE TEE client
>> driver, ICE needs to defer probe until the OPTEE ICE Pseudo TA becomes
>> available on the TEE bus. This means that for OPTEE builds without the
>> ICE PTA, the ICE driver would indefintely defer probe and the dependent
>> UFS/SDHC storage driver will fail to come online.
>>
>> Add support for optionally registering the back-end TEE devices which
>> represent a particular TEE (say OPTEE) on the platform bus via the
>> tee_platform_device_register() API. 

I've been thinking a bit more about this. Instead of introducing a new
API on the TEE subsystem for re-registering the back-end TEE device on a
platform/auxiliary bus, can we just register the (OP)TEE device on the TEE
bus itself once all the Pseudo TAs have been enumerated?

This could be a reserved device with a reserved UUID that the client drivers
cannot interact with via the usual tee_open_session() function, and would be
returned an error.

A TEE client driver who wants to be notified once all the PTAs have been
enumerated on the TEE bus can register for this reserved OPTEE UUID and be
informed of this event via its registered probe() function for this device.

The TEE back-end device would be a sort of "end-of-line" marker for all the
PTAs on the TEE bus.

Let me know your thoughts.

Regards,
Harshal

>> This allows drivers which poll on
>> TEE secure interface availability to be notified even if the TEE service
>> itself is not supported.
>>
>> Signed-off-by: Harshal Dev <harshal.dev@oss.qualcomm.com>
>> ---