Re: Deprecate the ppc405 boards in QEMU? (was: [PATCH v3 4/7] MAINTAINERS: Orphan obscure ppc platforms)

[Thomas Huth]

On 05/10/2021 08.18, Alexey Kardashevskiy wrote:
> On 05/10/2021 15:44, Christophe Leroy wrote:
> > Le 05/10/2021 à 02:48, David Gibson a écrit :
> > > On Fri, Oct 01, 2021 at 04:18:49PM +0200, Thomas Huth wrote:
> > > > On 01/10/2021 15.04, Christophe Leroy wrote:
> > > > > Le 01/10/2021 à 14:04, Thomas Huth a écrit :
> > > > > > On 01/10/2021 13.12, Peter Maydell wrote:
> > > > > > > On Fri, 1 Oct 2021 at 10:43, Thomas Huth <thuth@redhat.com> wrote:
> > > > > > > > Nevertheless, as long as nobody has a hint where to find that
> > > > > > > > ppc405_rom.bin, I think both boards are pretty useless in QEMU (as 
> > > > > > > > far as I
> > > > > > > > can see, they do not work without the bios at all, so it's
> > > > > > > > also not possible
> > > > > > > > to use a Linux image with the "-kernel" CLI option directly).
> > > > > > >
> > > > > > > It is at least in theory possible to run bare-metal code on
> > > > > > > either board, by passing either a pflash or a bios argument.
> > > > > >
> > > > > > True. I did some more research, and seems like there was once
> > > > > > support for those boards in u-boot, but it got removed there a
> > > > > > couple of years ago already:
> > > > > >
> > > > > > https://gitlab.com/qemu-project/u-boot/-/commit/98f705c9cefdf
> > > > > >
> > > > > > https://gitlab.com/qemu-project/u-boot/-/commit/b147ff2f37d5b
> > > > > >
> > > > > > https://gitlab.com/qemu-project/u-boot/-/commit/7514037bcdc37
> > > > > >
> > > > > > > But I agree that there seem to be no signs of anybody actually
> > > > > > > successfully using these boards for anything, so we should
> > > > > > > deprecate-and-delete them.
> > > > > >
> > > > > > Yes, let's mark them as deprecated now ... if someone still uses
> > > > > > them and speaks up, we can still revert the deprecation again.
> > > > >
> > > > > I really would like to be able to use them to validate Linux Kernel
> > > > > changes, hence looking for that missing BIOS.
> > > > >
> > > > > If we remove ppc405 from QEMU, we won't be able to do any regression
> > > > > tests of Linux Kernel on those processors.
> > > >
> > > > If you/someone managed to compile an old version of u-boot for one of these
> > > > two boards, so that we would finally have something for regression testing,
> > > > we can of course also keep the boards in QEMU...
> > >
> > > I can see that it would be usefor for some cases, but unless someone
> > > volunteers to track down the necessary firmware and look after it, I
> > > think we do need to deprecate it - I certainly don't have the capacity
> > > to look into this.
> >
> > I will look at it, please allow me a few weeks though.
>
> Well, building it was not hard but now I'd like to know what board QEMU 
> actually emulates, there are way too many codenames and PVRs.
>
> Here is what I was building:
> https://github.com/aik/u-boot/tree/ppc4xx-qemu
>
> CONFIG_SYS_ARCH="powerpc"
> CONFIG_SYS_CPU="ppc4xx"
> CONFIG_SYS_VENDOR="esd"
> CONFIG_SYS_BOARD="pmc405de"
> CONFIG_SYS_CONFIG_NAME="PMC405DE"
>
> Is this any use?

If I've got u-boot commit 98f705c9cefdfdba62c069821bbba10273a0a8
right, there used to be SYS_BOARD="405ep" config before that removal, so 
that sounds like a promising match for the ref405ep of QEMU?

The support for "taihu" even got removed earlier, in u-boot commit 
123b6cd7a4f75536734a7bff97db6eebce614bd1 , and the commit message says that 
it did not compile anymore at the end, so you might need to check out an 
even older version for that one.

 Thomas