[RFC] PCI: add CONFIG_MMU dependency

[Geert Uytterhoeven]

Hi Arnd,

CC Gerg

On Mon, 7 Apr 2025 at 12:40, Arnd Bergmann <arnd at kernel.org> wrote:
> From: Arnd Bergmann <arnd at arndb.de>
>
> It turns out that there are no platforms that have PCI but don't have an MMU,
> so adding a Kconfig dependency on CONFIG_PCI simplifies build testing kernels
> for those platforms a lot, and avoids a lot of inadvertent build regressions.
>
> Add a dependency for CONFIG_PCI and remove all the ones for PCI specific
> device drivers that are currently marked not having it.
>
> Link: https://lore.kernel.org/lkml/a41f1b20-a76c-43d8-8c36-f12744327a54@app.fastmail.com/
> Signed-off-by: Arnd Bergmann <arnd at arndb.de>

Thanks for your patch!

> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -21,6 +21,7 @@ config GENERIC_PCI_IOMAP
>  menuconfig PCI
>         bool "PCI support"
>         depends on HAVE_PCI
> +       depends on MMU
>         help
>           This option enables support for the PCI local bus, including
>           support for PCI-X and the foundations for PCI Express support.

While having an MMU is a hardware feature, I consider disabling MMU
support software configuration.  So this change prevents people from
disabling MMU support on a system that has both a PCI bus and an MMU.
But other people may not agree, or care?

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

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                                -- Linus Torvalds