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From:   Rob Herring <robh+dt@kernel.org>
Date:   Mon, 13 Sep 2021 16:13:26 -0500
Message-ID: <CAL_Jsq+OuYfuNM4pNL7aZ4tTHGTXzYcH1W-8xi=eEe2zOoq6nw@mail.gmail.com>
Subject: Re: [PATCH v3 02/10] of/irq: Allow matching of an interrupt-map local
 to an interrupt controller
To:     Marc Zyngier <maz@kernel.org>
Cc:     devicetree@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        PCI <linux-pci@vger.kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= <kw@linux.com>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        Stan Skowronek <stan@corellium.com>,
        Mark Kettenis <kettenis@openbsd.org>,
        Sven Peter <sven@svenpeter.dev>,
        Hector Martin <marcan@marcan.st>,
        Robin Murphy <Robin.Murphy@arm.com>,
        Android Kernel Team <kernel-team@android.com>
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On Mon, Sep 13, 2021 at 1:26 PM Marc Zyngier <maz@kernel.org> wrote:
>
> of_irq_parse_raw() has a baked assumption that if a node has an
> interrupt-controller property, it cannot possibly also have an
> interrupt-map property (the latter being ignored).
>
> This seems to be an odd behaviour, and there are no reason why

s/are/is/

> we should avoid supporting this use case. This is specially
> useful when a PCI root port acts as an interrupt controller for
> PCI endpoints, such as this:
>
> pcie0: pcie@690000000 {
>         [...]
>         port00: pci@0,0 {
>                 device_type = "pci";
>                 [...]
>                 #address-cells = <3>;
>
>                 interrupt-controller;
>                 #interrupt-cells = <1>;
>
>                 interrupt-map-mask = <0 0 0 7>;
>                 interrupt-map = <0 0 0 1 &port00 0 0 0 0>,
>                                 <0 0 0 2 &port00 0 0 0 1>,
>                                 <0 0 0 3 &port00 0 0 0 2>,
>                                 <0 0 0 4 &port00 0 0 0 3>;
>         };
> };
>
> Handle it by detecting that we have an interrupt-map early in the
> parsing, and special case the situation where the phandle in the
> interrupt map refers to the current node (which is the interesting
> case here).
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  drivers/of/irq.c | 17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)

Reviewed-by: Rob Herring <robh@kernel.org>