Re: [PATCH 4/4] dt-bindings: firmware: Add Qualcomm UEFI Secure Application client

Ilias Apalodimas
2022-07-28T12:25:02Z

On Thu, 28 Jul 2022 at 14:33, Sudeep Holla <sudeep.holla@arm.com> wrote:
>
> On Thu, Jul 28, 2022 at 12:48:19PM +0200, Maximilian Luz wrote:
>
> [...]
>
> >
> > I would very much like to avoid the need for special bootloaders. The
> > devices we're talking about are WoA devices, meaning they _should_
> > ideally boot just fine with EFI and ACPI.
> >
>
> Completely agreed.

This is not a special bootloader though. Quite the opposite. It's a
standard UEFI compliant bootloader, which uses the fact that EFI is
supposed to be extensible. It installs a linux specific config table,
similar to how we install a linux specific protocol to load our initrd
and it's certainly lot more scalable than adding new stuff to the
device tree.

>
> > From an end-user perspective, it's annoying enough that we'll have to
> > stick with DTs for the time being due to the use of PEPs in ACPI.
>
> But have we explored or investigated what it takes to rewrite ACPI f/w
> to just use standard methods ? Does it require more firmware changes or
> new firmware entities or impossible at any cost ?
>
> For me that is more important than just getting this one on DT. Because
> if you take that path, we will have to keep doing that, with loads of
> unnecessary drivers if they are not shared with any other SoC with DT
> support upstream. We might also miss chance to get things added to the ACPI
> spec as we don't care which means that we never be able to use ACPI on
> similar future platforms even though they get shipped with ACPI.
>
> It will be a loop where we constantly keep converting this ACPI shipped
> platform into DT upstream. IMHO we don't want to be there.
>
> --
> Regards,
> Sudeep

Regards
/Ilias