Re: [PATCH] hw/ppc: Deprecate the ref405ep and taihu machines and the 405 CPU models

[Peter Maydell <peter.maydell@linaro.org>]

On Fri, 1 Oct 2021 at 13:22, Thomas Huth <thuth@redhat.com> wrote:
>
> These machines need a firmware image called 'ppc405_rom.bin', and nobody
> seems to have such a firmware image left for testing, so the machines are
> currently unusable. There used to be support in U-Boot, but it has been
> removed a couple of year ago already.
> Thus let's mark these boards and the 405 CPU as deprecated now, so that we
> could remove them in a couple of releases (unless somebody speaks up and
> says that these are still usefull for them).
>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  docs/about/deprecated.rst | 15 +++++++++++++++
>  hw/ppc/ppc405_boards.c    |  2 ++
>  2 files changed, 17 insertions(+)
>
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index 2f7db9a98d..27c03ef624 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -238,6 +238,11 @@ The ``I7200`` guest CPU relies on the nanoMIPS ISA, which is deprecated
>  (the ISA has never been upstreamed to a compiler toolchain). Therefore
>  this CPU is also deprecated.
>
> +PPC 405 CPU models (since 6.2)
> +''''''''''''''''''''''''''''''
> +
> +The related boards ``ref405ep`` and ``taihu`` are marked as deprecated, too.
> +

What is this "too" a reference to? The immediately preceding section
in the document is about the MIPS I7200 CPU model.

The not-being-deprecated sam460ex board also uses the ppc405 CPU
I think, so I don't think we can drop the CPU models.

>  QEMU API (QAPI) events
>  ----------------------
> @@ -258,6 +263,16 @@ This machine is deprecated because we have enough AST2500 based OpenPOWER
>  machines. It can be easily replaced by the ``witherspoon-bmc`` or the
>  ``romulus-bmc`` machines.
>
> +``ref405ep`` and ``taihu`` machines (since 6.2)
> +'''''''''''''''''''''''''''''''''''''''''''''''
> +
> +These machines need a firmware image called 'ppc405_rom.bin', and nobody seems
> +to have a working copy of such a firmware image anymore. `Support in U-Boot

"any more".

> +<https://gitlab.com/qemu-project/u-boot/-/commit/98f705c9cefdfdba62c069>`__
> +has been removed a couple of years ago, too, so it is very unlikely that
> +anybody is still using this code at all.

(I'm not sure whether anybody ever actually successfully booted a
u-boot binary on QEMU's taihu/ref405ep boards.)

> +
> +
>  Backend options
>  ---------------
>
> diff --git a/hw/ppc/ppc405_boards.c b/hw/ppc/ppc405_boards.c
> index 972a7a4a3e..1578c0dac8 100644
> --- a/hw/ppc/ppc405_boards.c
> +++ b/hw/ppc/ppc405_boards.c
> @@ -317,6 +317,7 @@ static void ref405ep_class_init(ObjectClass *oc, void *data)
>      mc->init = ref405ep_init;
>      mc->default_ram_size = 0x08000000;
>      mc->default_ram_id = "ef405ep.ram";
> +    mc->deprecation_reason = "ppc405 CPU is deprecated";
>  }
>
>  static const TypeInfo ref405ep_type = {
> @@ -547,6 +548,7 @@ static void taihu_class_init(ObjectClass *oc, void *data)
>      mc->init = taihu_405ep_init;
>      mc->default_ram_size = 0x08000000;
>      mc->default_ram_id = "taihu_405ep.ram";
> +    mc->deprecation_reason = "ppc405 CPU is deprecated";
>  }

We're not deprecating the machine types because we're deprecating
the CPU types. We're deprecating them because we believe that
nobody's using them.

-- PMM