[PATCH 1/2] arc: Rework Kconfig choice menus

[Tom Rini]

On Tue, Mar 18, 2025 at 08:32:10PM +0000, Alexey Brodkin wrote:
> Hi Tom,
> 
> > Currently we get a number of warnings about using "select" statements
> > on "choice" options and that this as no effect. Rework some of these so
> > that we use "depends on" rather than select for the CPU, and have the
> > CPU select the MMU version. The MMU version is no longer prompted for.
> 
> Thanks a lot for these fixes.
> 
> I'm wondering though if these warnings only have started to appear recently,
> i.e. how come we haven't notice them before?

They've always existed, it's just that you need to run a Kconfig linting
tool to get them. We have one (which can be invoked two ways) and it's a
bit verbose and notes many things as possible issues, rather than
definitively something as an issue.

> > Signed-off-by: Tom Rini <trini at konsulko.com>
> > ---
> > Cc: Alexey Brodkin <alexey.brodkin at synopsys.com>
> > Cc: Eugeniy Paltsev <Eugeniy.Paltsev at synopsys.com>
> > Cc: uboot-snps-arc at synopsys.com
> > ---
> >  arch/arc/Kconfig | 22 ++++++----------------
> >  1 file changed, 6 insertions(+), 16 deletions(-)
> >
> > diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
> > index 6ae66bb163c0..be9774dc2896 100644
> > --- a/arch/arc/Kconfig
> > +++ b/arch/arc/Kconfig
> > @@ -66,28 +66,20 @@ config CPU_ARCHS38
> >
> >  endchoice
> >
> > -choice
> > -       prompt "MMU Version"
> > -       default ARC_MMU_V3 if CPU_ARC770D
> > -       default ARC_MMU_V2 if CPU_ARC750D
> > -       default ARC_MMU_ABSENT if CPU_ARCEM6
> > -       default ARC_MMU_ABSENT if CPU_ARCHS36
> > -       default ARC_MMU_V4 if CPU_ARCHS38
> 
> Well, here the idea was that some users may want to override
> MMU settings for their particular SoC/design. See ARC cores are very
> configurable and it's possible to mix and match certain components.
> 
> For example, it's possible to start from a full-blown ARC770 and
> deconfigure MMU from it, effectively getting something like ARC725,
> but not exactly as some other properties of ARC770 will still be in place
> as opposed to a true ARC725.
> 
> Thus we used to have a "default" which comes with a particular template
> (ARC770D for example) with ability to override it.
> 
> >  config ARC_MMU_ABSENT
> > -       bool "No MMU"
> > +       bool
> 
> I thought that comment of these "bool" values will be seen in "menuconfig" GUI
> helping a user to see what's that...
> 
> [snip]
> 
> >  config ARC_MMU_VER
> >          int
> >          default 0 if ARC_MMU_ABSENT
> > @@ -172,14 +162,14 @@ config TARGET_AXS103
> >
> >  config TARGET_EMSDP
> >          bool "Synopsys EM Software Development Platform"
> > -       select CPU_ARCEM6
> > +       depends on CPU_ARCEM6
> 
> Here we had "select" because this particualr board (EM Software Development Platform)
> does come with ARC EM6 CPU, and so I though that selection of the board enforces use
> of the processor. But maybe I'm wrong here i nhow that's meant to be implemented
> properly.

So, with more details on what the intention was I need to think
harder about what to suggest as a fix. The good news at least is that
for this patch, doing nothing won't change the behavior we have today.

It might just be that we drop the select/imply statements, except for
TARGET_EMSDP which requires thinking harder still, and expand the help
texts.

-- 
Tom
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