[U-Boot] [PATCH v4 08/12] doc: TEE: Add documentation describing TEE in u-boot

[Andrew F. Davis]

On 02/26/2018 09:06 AM, Bryan O'Donoghue wrote:
> 
> 
> On 26/02/18 14:56, Dr. Philipp Tomsich wrote:
>> Now, I am confused.
> 
> Fair enough.
> 
> In my view there are really only two required paths i.e. kever's stuff
> can use the existing "tee" type, let's not discuss a third option further.
> 
> So for clarity the proposal is
> 
> 1. Maintain the existing "tee" as is.
> 
>    As regards changing the name of "tee" to "tee-standalone" I'd like
>    to get Tom or Andrew (both) to say that's what is wanted.
> 
>    Since it's TI boards that are using the "tee" name in mkimage
>    upstream the name-change is churn there.
> 
>    Andrew, Tom ?
> 

I wouldn't be too opposed to the name change if we decide to go down
this two type path, but I'm still not convinced we are doing the right
thing here.

Lets look at u-boot/include/image.h for a moment, the table of IH_TYPE_*
already has a type for what we are trying to do here: IH_TYPE_KERNEL.
The comment on this table describes "OS Kernel Images" as exactly what
you are doing with your TEE image.

To me what you really want to do is add a new IH_OS_*, which are defined
in a different table above (I see this is already done for ATF
(IH_OS_ARM_TRUSTED_FIRMWARE) which shares a similar “boot-through” flow
like Philipp pointed out).

So I'm still not sure what the technical reason you need a new "type" of
image, when adding your hooks to the existing IH_TYPE_KERNEL path in
U-Boot could be made to do the same thing when it encounters a IH_OS_TEE
OS image.

Andrew

> 2. Add a new bootable type
>    The set of names we have for that is
> 
>    {tee-bootable, tee-chainload, tee-with-payload}
> 
>    I have no strong feelings about the name for the new type either way
> 
>    :)