Re: [Qemu-devel] [Qemu-ppc] [PATCH v3 2/2] ppc: Add aCube Sam460ex board

[Thomas Huth <thuth@redhat.com>]

On 20.02.2018 12:16, BALATON Zoltan wrote:
> On Tue, 20 Feb 2018, Alexander Graf wrote:
>> On 02/20/2018 11:09 AM, BALATON Zoltan wrote:
>>> On Tue, 20 Feb 2018, David Gibson wrote:
>>>> On Mon, Feb 19, 2018 at 11:34:25AM +0100, BALATON Zoltan wrote:
>>>> 1;5002;0c> Add emulation of aCube Sam460ex board based on AMCC 460EX
>>>> embedded SoC.
>>>>> This is not a complete implementation yet with a lot of components
>>>>> still missing but enough for the U-Boot firmware to start and to boot
>>>>> a Linux kernel or AROS.
>>>>>
>>>>> Signed-off-by: François Revol <revol@free.fr>
>>>>> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
>>>>
>>>> I'm not thrilled with having a machine type that can't be used without
>>>> extracting a bootloader image from somewhere, but from the other
>>>> thread that's not easy to fix.
>>>
>>> This is not meant to be like that and I'd like to also submit the
>>> u-boot image once we figure out how to do it. Especially because the
>>> boot loader one can extract from the updater is buggy but here's a
>>> fixed binary that works here: http://zero.eik.bme.hu/~balaton/qemu/
>>>
>>> U-Boot is GPL so we would need to include the source as well (the
>>> README in the link above contain the source URL and the patches
>>> needed are there as well). If there's no easy way to host it in the
>>> QEMU repo I could put it in my own git repo and submit a patch to use
>>> that as a submodule if that's acceptable. It seems there are some
>>> firmware images that reference external git repos already but not
>>> sure what's the preferred way.
>>
>> IMHO the preferred way would be to integrate sam460ex support in
>> upstream U-Boot and just build it from there. We already mirror U-Boot
>> on git.qemu.org and package up that tree, so packaging up one more
>> target from there would be trivial.
> 
> As discussed in other thread that's not really feasible. Upstream U-Boot
> has removed support for this CPU and the board code was never upstreamed
> by the hardware vendor. I'm not willing to take the task of porting this
> to latest U-Boot, re-adding all necessary CPU support to latest U-Boot
> and then take on supporting all this in future versions. So it has to be
> a separate source or you'd have to downgrade U-Boot on git.qemu.org to
> the older version where the patch applies (but that's not desired as
> this old version has some bugs which are fixed in later U-Boot
> versions). We also cannot omit the vendor patches to U-Boot and use
> latest upstream U-Boot for this board because guests rely on these
> firmware modifications to boot. So I see no way to have one U-Boot
> version to be used by both e500 and sam460ex even if it means adding
> another U-Boot source (but this source is fairly static, I don't expect
> many changes to it so it won't diverge more than it is now and we mainly
> need to add it to satisfy GPL so we can bundle the binary).

Not sure, but would it maybe be possible to simply include a diff patch
file between the version of u-boot that we ship in QEMU and the version
that is required for the sam460ex in the roms/ directory?

 Thomas