Hi Dan,

Thanks for your reply.

I thought option2 maybe a good choice, but ARMv7 does not have EL3 as v8, so needs a tight coupling between U-Boot and TEE which is not good.

We want to make TEE an optional component in our software,  but seems only option3 is acceptable now.

Thanks,

Peng.

From: Tee-dev [mailto:tee-dev-bounces@lists.linaro.org] On Behalf Of Dan Handley
Sent: Tuesday, November 15, 2016 3:49 AM
To: tee-dev@lists.linaro.org
Subject: Re: [Tee-dev] Introduce PSCI for OP-TEE ARM32

Hi Peng

I've just joined this mailing list after being pointed to this thread.

As ARM Trusted Firmware (TF) tech lead, I strongly encourage option 3, assuming you mean using the standalone AArch32 PSCI library provided in the upstream TF code base.

If by Option 1 you mean a full port of TF to AArch32, we consider this not feasible due to the architectural limitations that Jens described in his mail earlier. These limitations are also described in the presentation I gave at the last Linaro Connect in Las Vegas.

Option 2 is going to be equally challenging. Apart from being very difficult, there would be very tight coupling between U-Boot and OP-TEE, which may not be desirable for OP-TEE.

It's true that TF AArch32 support is currently focussed on ARMv8-A AArch32 support, but adding support for ARMv7-A is not a major task. We just need some help from the TF community to implement this.

In terms of implementing Option 3, Joakim mentioned looking into this early next year. We too were thinking of looking into this around the same time. I echo his comments around you helping with this if you want. We (ARM) are happy to provide consultancy.

In any case, we should agree among ourselves what the plan is before anyone embarks on this work!

Regards

Dan.

On 11 November 2016 at 10:21, Peng Fan <peng.fan at nxp.com> wrote:

> Hi,

>

>

> I am trying to implement TEE and support Linux power features.

>

>

>

> There are several options to include power features and TEE

>

> 1. ATFW for ARM32.

>

> 2. Develop runtime service code in U-Boot like ATFW.

>

> 3. Integrate PSCI ARM32 in OP-TEE.

>

>

>

> Option1, ATFW seems not support ARM32, such as A9/A7. And the AArch32

> support, I think(not sure), is not for legacy ARM32 cores.

>

> Option2, requires some efforts. And needs some wrap code between uboot

> monitor code and TEE and Linux.

>

> Actually I prefer option3, and secondary cores can be booted up with psci in

> OP-TEE. Before I

>

> put more efforts, I would like to ask whether this is acceptable from OP-TEE

> community.

>

>

>

> Thanks,

>

> Peng.

>

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