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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Tue, 16 Feb 2021 13:58:37 +0100
Message-ID: <CAMuHMdULCQrjba0sM3wUFdPDTB4Txh3LVY-8ACq6P_vFJvk+SA@mail.gmail.com>
Subject: Re: [PATCH v4 0/8] Make fw_devlink=on more forgiving
To:     Saravana Kannan <saravanak@google.com>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Kevin Hilman <khilman@kernel.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Len Brown <len.brown@intel.com>, Len Brown <lenb@kernel.org>,
        Pavel Machek <pavel@ucw.cz>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Marc Zyngier <maz@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux PM list <linux-pm@vger.kernel.org>,
        linux-clk <linux-clk@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Android Kernel Team <kernel-team@android.com>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>
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Hi Saravana,

On Mon, Feb 15, 2021 at 10:57 PM Saravana Kannan <saravanak@google.com> wrote:
> On Mon, Feb 15, 2021 at 7:16 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Fri, Feb 12, 2021 at 4:00 AM Saravana Kannan <saravanak@google.com> wrote:
> > > On Thu, Feb 11, 2021 at 5:00 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > >   1. R-Car Gen2 (Koelsch), R-Car Gen3 (Salvator-X(S), Ebisu).
> > > >
> > > >       - Commit 2dfc564bda4a31bc ("soc: renesas: rcar-sysc: Mark device
> > > >         node OF_POPULATED after init") is no longer needed (but already
> > > >         queued for v5.12 anyway)
> > >
> > > Rob doesn't like the proliferation of OF_POPULATED and we don't need
> > > it anymore, so maybe work it out with him? It's a balance between some
> > > wasted memory (struct device(s)) vs not proliferating OF_POPULATED.
> >
> > > >   2. SH/R-Mobile AG5 (kzm9g), APE6 (ape6evm), A1 (armadillo800-eva)
> > > >
> > > >       - "PATCH] soc: renesas: rmobile-sysc: Set OF_POPULATED and absorb
> > > >         reset handling" is no longer needed
> > > >         https://lore.kernel.org/linux-arm-kernel/20210205133319.1921108-1-geert+renesas@glider.be/
> > >
> > > Good to see more evidence that this series is fixing things at a more
> > > generic level.
> >
> > I spoke too soon: if CONFIG_POWER_RESET_RMOBILE=n,
> > booting fails again, as everything is waiting on the system controller,
> > which never becomes available.
> > Rcar-sysc doesn't suffer from this problem, cfr. above.
> > Perhaps because the rmobile-sysc bindings use a hierarchical instead
> > of a linear PM domain description, and thus consumers point to the
> > children of the system controller node?
> > Cfr. system-controller@e6180000 in arch/arm/boot/dts/r8a7740.dtsi.
>
> Ok, I see what's going on. The problem is that the "power domain"
> fwnode being registered is not the node that contains the "compatible"
> property and becomes a device. So this patch[1] is not helping here.
> Fix is to do something like this (to avoid using OF_POPULATED flag and
> breaking reset):
>
> diff --git a/drivers/soc/renesas/rmobile-sysc.c
> b/drivers/soc/renesas/rmobile-sysc.c
> index 9046b8c933cb..b7e66139ef7d 100644
> --- a/drivers/soc/renesas/rmobile-sysc.c
> +++ b/drivers/soc/renesas/rmobile-sysc.c
> @@ -344,6 +344,7 @@ static int __init rmobile_init_pm_domains(void)
>                         of_node_put(np);
>                         break;
>                 }
> +               fwnode_dev_initialized(&np->fwnode, true);
>         }
>
>         put_special_pds();
>
> Can you give it a shot?

Thanks, works.  Patch sent
"[PATCH v2] soc: renesas: rmobile-sysc: Mark fwnode when PM domain is added"
https://lore.kernel.org/linux-arm-kernel/20210216123958.3180014-1-geert+renesas@glider.be/

Gr{oetje,eeting}s,

                        Geert

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

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds