Re: [PATCH 11/13] arm: npcm: drop selecting non-existing ARM_ERRATA_794072

[Lukas Bulwahn]

On Fri, Oct 29, 2021 at 8:36 AM Joel Stanley <joel@xxxxxxxxx> wrote:
>
> On Thu, 28 Oct 2021 at 14:57, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> >
> > On Thu, Oct 28, 2021 at 4:19 PM Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx> wrote:
> > >
> > > There is no and never was a Kconfig for ARM_ERRATA_794072 in the kernel
> > > tree. So, there is no need to select ARM_ERRATA_794072 in
> > > ./arch/arm/mach-npcm/Kconfig.
> > >
> > > Simply drop selecting the non-existing ARM_ERRATA_794072.
> > >
> > > This issue was discovered with ./scripts/checkkconfigsymbols.py.
> > >
> > > Signed-off-by: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>
> > > ---
> >
> > Could this be a typo? Maybe we need to enable a different errata workaround
> > here, or maybe that code is actually needed and has to get sent.
>
> Doing some searching, u-boot had a workaround for something called
> ARM_ERRATA_794072.
>
> https://github.com/u-boot/u-boot/commit/f71cbfe3ca5d2ad20159871700e8e248c8818ba8
>
> Lore has the review history for that patch:
>
> https://lore.kernel.org/all/6be32e0b5b454ed7b609317266a8e798@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
>
> It looks like it's the same workaround as ARM_ERRATA_742230, which the
> kernel does implement.
>
> It would be good to hear from the Nuvoton people, or an Arm person.
>

I will happily update the patch to select ARM_ERRATA_742230 instead of
the dead non-existing ARM_ERRATA_794072.

In contrast to the current patch that basically only cleans up "dead
config" and has no effective functional change, the new patch would
change the behaviour. I cannot test this patch (beyond some basic
compile test) on the hardware; so, we certainly need someone to have
that hardware, knows how to test it or confirm otherwise that we
should select the ARM_ERRATA_742230 fix for this hardware.

The current patch should be subsumed by the new patch; the submission
of the new patch is deferred until that person shows up. Let's see.

Lukas