[PowerPC] [PASEMI] Issue with the identification of ATA drives after the of/irq updates 2024-05-29

[Rob Herring]

On Tue, Jul 2, 2024 at 10:54 AM Marc Zyngier <maz at kernel.org> wrote:
>
> On Sun, 30 Jun 2024 11:21:55 +0100,
> Christian Zigotzky <chzigotzky at xenosoft.de> wrote:
> >
> > Hello,
> >
> > There is an issue with the identification of ATA drives with our
> > P.A. Semi Nemo boards [1] after the
> > commit "of/irq: Factor out parsing of interrupt-map parent
> > phandle+args from of_irq_parse_raw()" [2].
>
> [snip]
>
> My earlier request for valuable debug information still stands. But
> while you're at it, can you please give the following hack a go?
>
>         M.
>
> --- a/drivers/of/irq.c
> +++ b/drivers/of/irq.c
> @@ -282,8 +282,10 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
>
>                         oldimap = imap;
>                         imap = of_irq_parse_imap_parent(oldimap, imaplen, out_irq);
> -                       if (!imap)
> -                               goto fail;
> +                       if (!imap) {
> +                               match = 0;
> +                               break;
> +                       }

AFAICT reading the DT, I don't think this would fix it. imap should
only be null if malformed. This case to me looks like interrupt-map
has the correct cell sizes, but just never matches to do the mapping.
So maybe imaplen is off and that causes us to end up here, but if
there's an error I don't see it. A boot with DEBUG enabled in
drivers/of/irq.c would help.

>
>                         match &= of_device_is_available(out_irq->np);
>                         if (match)
>
> This may not be the final workaround even if it solves your boot
> problem, but will at least give us a hint at what is going wrong.
>
> I have the fuzzy feeling that we may be able to lob this broken system
> as part of the of_irq_imap_abusers[] array, which would solve things
> pretty "neatly".

I think this would work and would consolidate the work-arounds. It
would need either "pasemi,rootbus" or "pa-pxp" added to the list.

Rob