[U-Boot] imx7d: CPU core issue in secure mode

[Igor Opaniuk]

+ Peng

Hi Tobias, Peng,

On Thu, Jul 4, 2019 at 2:20 PM Tobias Junghans <tobias.junghans at veyon.io> wrote:
>
> Hi,
>
> I'm trying to get an imx7d-based Colibris board running in secure mode in
> order to be able to use the CAAM, especially the HWRNG. However it seems like
> it's currently not possible to boot a mainline kernel (4.19) in secure mode
> with both CPU cores powered up, likely due to the missing PSCI firmware in
> secure mode. When booting in nonsecure mode the kernel recognizes both CPU
> cores while CAAM isn't working. Basically it's the same issue as discussed at
>
> https://www.spinics.net/lists/u-boot-v2/msg33873.html
>
> I'm using the latest mainline U-Boot (2019.07-rc4) with
> CONFIG_ARMV7_BOOT_SEC_DEFAULT=y. Is there anything I can do about this issue?
>
> Thank you and best regards
>
> Tobias
>
>
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I might be mistaken, but AFAIK there was on-going work done by Peng
Fan regarding
proper CAAM initialization in the OP-TEE and further usage in the
mainline kernel.

As I understood, the initial initialization of the jobrings is done in OP-TEE
(which is booted before U-boot) in secure world, and then linux kernel,
running in normal world, should be able to use it.
Regarding PSCI, frankly, I have no idea who particularly should provide it's
support here: U-boot or OP-TEE (taking into account that in this setup
U-boot is booted in non-secure PL2, so OP-TEE is the only one, who is
able to provide secure
runtime services, so-called secure monitor).

BTW, I also saw some setups, where similar things to do the same in
U-boot (when it's booted in secure mode),
which also does have it's own implementation of secure
monitor(subsequently PSCI) and CAAM driver,
which probably does the same type of initialization, as in OP-TEE.


Peng,
Could you please provide some comments regarding this? Thanks!

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Igor Opaniuk

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