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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Fri, 3 Aug 2018 11:26:41 +0200
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Subject: Re: [Qemu-devel] [PATCH v2 2/2] hw/arm: Add Arm Enterprise machine
 type
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Hongbo Zhang <hongbo.zhang@linaro.org>, Andrew Jones <drjones@redhat.com>, Radoslaw Biernacki <radoslaw.biernacki@linaro.org>, QEMU Developers <qemu-devel@nongnu.org>, Leif Lindholm <leif.lindholm@linaro.org>, qemu-arm <qemu-arm@nongnu.org>, =?UTF-8?B?QWxleCBCZW5uw6ll?= <alex.bennee@linaro.org>

On 3 August 2018 at 11:23, Peter Maydell <peter.maydell@linaro.org> wrote:
> On 3 August 2018 at 10:21, Hongbo Zhang <hongbo.zhang@linaro.org> 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.