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

[Thomas Huth <thuth@redhat.com>]

On 05/10/2021 10.05, Alexey Kardashevskiy wrote:
> 
> 
> On 05/10/2021 17:42, Thomas Huth wrote:
>> 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?
> 
> Tricky. The board can be 405ep if 
> TARGET_IO/TARGET_DLVISION/TARGET_DLVISION_10G selected. Neither compiles at 
> 98f705c9cefdfdba62c^ due to missing CONFIG_SYS_PCI_PTM1PCI :-/
> 
>>
>> 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.
> 
> 
> What is so special about taihu?

taihu is the other 405 board defined in hw/ppc/ppc405_boards.c (which I 
suggested to deprecate now)

  Thomas