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From:   Saravana Kannan <saravanak@google.com>
Date:   Thu, 4 Feb 2021 13:31:13 -0800
Message-ID: <CAGETcx_KDA55Ti=5CHw48BP1L2Xo64=AFFe+17g27n=P-KUrow@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] of: property: Add fw_devlink support for interrupts
To:     Marek Szyprowski <m.szyprowski@samsung.com>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-tegra <linux-tegra@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Jon Hunter <jonathanh@nvidia.com>,
        Marc Zyngier <maz@kernel.org>,
        Kevin Hilman <khilman@baylibre.com>,
        Android Kernel Team <kernel-team@android.com>,
        Rob Herring <robh@kernel.org>,
        Thierry Reding <treding@nvidia.com>
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On Thu, Feb 4, 2021 at 3:52 AM Marek Szyprowski
<m.szyprowski@samsung.com> wrote:
>
> Hi Saravana,
>
> On 21.01.2021 23:57, Saravana Kannan wrote:
> > This allows fw_devlink to create device links between consumers of an
> > interrupt and the supplier of the interrupt.
> >
> > Cc: Marc Zyngier <maz@kernel.org>
> > Cc: Kevin Hilman <khilman@baylibre.com>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Reviewed-by: Rob Herring <robh@kernel.org>
> > Reviewed-by: Thierry Reding <treding@nvidia.com>
> > Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> > Signed-off-by: Saravana Kannan <saravanak@google.com>
>
> This patch landed some time ago in linux-next as commit 4104ca776ba3
> ("of: property: Add fw_devlink support for interrupts"). It breaks MMC
> host controller operation on ARM Juno R1 board (the mmci@50000 device
> defined in arch/arm64/boot/dts/arm/juno-motherboard.dtsi). I didn't

I grepped around and it looks like the final board file is this or
whatever includes it?
arch/arm64/boot/dts/arm/juno-base.dtsi

This patch just finds the interrupt-parent and then tries to use that
as a supplier if "interrupts" property is listed. But the only
interrupt parent I can see is:
        gic: interrupt-controller@2c010000 {
                compatible = "arm,gic-400", "arm,cortex-a15-gic";

And the driver uses IRQCHIP_DECLARE() and hence should be pretty much
a NOP since those suppliers are never devices and are ignored.
$ git grep "arm,gic-400" -- drivers/
drivers/irqchip/irq-gic.c:IRQCHIP_DECLARE(gic_400, "arm,gic-400", gic_of_init);

This doesn't make any sense. Am I looking at the right files? Am I
missing something?

-Saravana