[U-Boot] [PATCH 3/3] image: fdt: copy possible optee nodes to a loaded devicetree

[Heiko Stübner]

Hi Simon,

Am Dienstag, 22. Oktober 2019, 02:17:00 CEST schrieb Simon Glass:
> On Mon, 7 Oct 2019 at 18:22, Heiko Stuebner <heiko at sntech.de> wrote:
> >
> > The loading convention for optee or any other tee on arm64 is as bl32
> > parameter to the trusted-firmware. So TF-A gets invoked with the TEE as
> > bl32 and main u-boot as bl33. Once it has done its startup TF-A jumps
> > into the bl32 for the TEE startup, returns to TF-A and then jumps to bl33.
> >
> > All of them get passed a devicetree as parameter and all components often
> > get loaded from a FIT image.
> >
> > OP-TEE will create additional nodes in that devicetree namely a firmware
> > node and possibly multiple reserved-memory nodes.
> >
> > While this devicetree is used in main u-boot, in most cases it won't be
> > the one passed to the actual kernel. Instead most boot commands will load
> > a new devicetree from somewhere like mass storage of the network, so if
> > that happens u-boot should transfer the optee nodes to that new devicetree.
> >
> > To make that happen introduce optee_copy_fdt_nodes() called from the dt
> > setup function in image-fdt which after checking for the optee presence
> > in the u-boot dt will make sure a optee node is present in the kernel dt
> > and transfer any reserved-memory regions it can find.
> >
> > Signed-off-by: Heiko Stuebner <heiko at sntech.de>
> > ---
> > This goes together with my bl32 work for the spl_atf loader in
> > https://patchwork.ozlabs.org/patch/1172565/
> >
> >  common/image-fdt.c  |   8 ++++
> >  include/tee/optee.h |   9 ++++
> >  lib/optee/optee.c   | 112 ++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 129 insertions(+)
> 
> Could we please get a test for this new functionality?

We can try ;-) , but I think I'll need some pointers how this should be done.

On first glance, test/overlay/* seems to be a good inspiration. Aka the new
function relies on an opaque OP-TEE binary modifying the .itb's dt-blob
between SPL and main-U-Boot, so working with stub devicetrees for
testing seems reasonable.

Aka checking cases of optee-nodes in old_fdt and not having them.

Looking at the README though points me to "TODO: convert to pytest" it
seems. Though that README.md only talks about interacting with the
u-boot console, so I'm not sure how that should work.


Thanks
Heiko