Re: [Qemu-arm] [Qemu-devel] [PATCH v2 2/2] hw/arm: Add Arm Enterprise machine type

[Andrew Jones]

On Fri, Aug 03, 2018 at 11:26:41AM +0200, Ard Biesheuvel wrote:
> On 3 August 2018 at 11:23, Peter Maydell <address@hidden> wrote:
> > On 3 August 2018 at 10:21, Hongbo Zhang <address@hidden> wrote:
> >> The 'sbsa' machine won't consume QEMU generated ACPI, so it won't
> >> touch or add new ACPI tables.
> >>
> >> UEFI relies on its ACPI to load OS, but currently it still needs DT
> >> from QEMU to pass some info, one example is CPU number.
> >>
> >> So, the 'sbsa' code implementation should be like this:
> >> A separate file, no ACPI codes, a little necessary DT codes.
> >>
> >> "Necessary DT codes" doesn't include so many peripheral devices nodes,
> >> so the code overlap with virt won't be so much (contrary to sbsa.c
> >> with all the DT codes), then no need to separate the common part to a
> >> third file, and virt.c can be untouched or only a minor change with
> >> few lines.
> >
> > Would the real hardware you are trying to be an example
> > for use DT for this? It seems a bit unlikely to me.
> >
> 
> Yes, as a matter of fact. There is work underway both on the EDK2 and
> the ARM-TF side to rely less on static descriptions, and more on DT to
> instantiate drivers and ACPI tables at runtime rather than at build
> time.

Hi Ard,

(A bit off-topic, but related to your comment above.)

I started poking at teaching ArmVirtQemu how to get the base of RAM
from the DTB, where the DTB is passed to it through x1 (QEMU needed a
few new lines to ensure x1 had it in the firmware=y,-kernel=no case
too). I have the assembler written, but I got hung up on the integration
with edk2, because I don't understand the build files well enough yet to
swap in ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S for the ArmVirtQemu
platform. I would also need to clean up the assembler a bit before
posting. I'll be out-of-office for all next week, but if you send me
some edk2 pointers in the meantime, then I should be able to post an
RFC the following week.

Thanks,
drew