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From:   Rob Herring <robh@kernel.org>
Date:   Mon, 6 Dec 2021 12:59:48 -0600
Message-ID: <CAL_JsqJd4tgTGGypA+Zj4VEoXthFksSHhmyc_MSEZzdTvHVT4A@mail.gmail.com>
Subject: Re: [PATCH] of/irq: Add a quirk for controllers with their own
 definition of interrupt-map
To:     "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Cc:     Marc Zyngier <maz@kernel.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "kernel-team@android.com" <kernel-team@android.com>,
        John Crispin <john@phrozen.org>, Biwen Li <biwen.li@nxp.com>,
        Chris Brandt <Chris.Brandt@renesas.com>,
        "linux-renesas-soc@vger.kernel.org" 
        <linux-renesas-soc@vger.kernel.org>
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On Mon, Dec 6, 2021 at 10:55 AM Lad, Prabhakar
<prabhakar.csengg@gmail.com> wrote:
>
> On Mon, Dec 6, 2021 at 10:26 AM Marc Zyngier <maz@kernel.org> wrote:
> >
> > On Sun, 05 Dec 2021 22:27:35 +0000,
> > "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote:
> > >
> > > On Wed, Dec 1, 2021 at 4:16 PM Lad, Prabhakar
> > > <prabhakar.csengg@gmail.com> wrote:
> > > >
> > > > On Wed, Dec 1, 2021 at 2:36 PM Rob Herring <robh@kernel.org> wrote:
> > > > >
> > > > > On Wed, Dec 1, 2021 at 7:37 AM Lad, Prabhakar
> > > > > <prabhakar.csengg@gmail.com> wrote:
> > > > > >
> > > > > > Hi Marc/Rob,
> > > > > >
> > > > > > On Tue, Nov 30, 2021 at 6:37 PM Marc Zyngier <maz@kernel.org> wrote:
> > > > > > >
> > > > > > > On Tue, 30 Nov 2021 12:52:21 +0000,
> > > > > > > "Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote:
> > > > > > > >
> > > > > > > > On Mon, Nov 29, 2021 at 6:33 PM Rob Herring <robh@kernel.org> wrote:
> > > > > > > > >
> > > > > > > > > interrupts would work just fine here:
> > > > > > > > >
> > > > > > > > > interrupts = <GIC_SPI 4 IRQ_TYPE_LEVEL_HIGH>,
> > > > > > > > >   <GIC_SPI 5 IRQ_TYPE_LEVEL_HIGH>,
> > > > > > > > >   <GIC_SPI 6 IRQ_TYPE_LEVEL_HIGH>,
> > > > > > > > >   <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
> > > > > > > > >   <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
> > > > > > > > >   <GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>,
> > > > > > > > >   <GIC_SPI 10 IRQ_TYPE_LEVEL_HIGH>,
> > > > > > > > >   <GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>;
> > > > > > > > >
> > > > > > > > > We don't need a different solution for N:1 interrupts from N:M. Sure,
> > > > > > > > > that could become unweldy if there are a lot of interrupts (just like
> > > > > > > > > interrupt-map), but is that an immediate problem?
> > > > > > > > >
> > > > > > > > It's just that with this approach the driver will have to index the
> > > > > > > > interrupts instead of reading from DT.
> > > > > > > >
> > > > > > > > Marc - is it OK with the above approach?
> > > > > > >
> > > > > > > Anything that uses standard properties in a standard way works for me.
> > > > > > >
> > > > > > I added interrupts property now instead of interrupt-map as below:
> > > > > >
> > > > > > irqc: interrupt-controller@110a0000 {
> > > > > >       compatible = "renesas,r9a07g044-irqc", "renesas,rzg2l-irqc";
> > > > > >        #address-cells = <0>;
> > > > > >        interrupt-parent = <&gic>;
> > > > > >        interrupt-controller;
> > > > > >        reg = <0 0x110a0000 0 0x10000>;
> > > > > >        interrupts =
> > > > > >                       <GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 4 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 5 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 6 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 444 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 445 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 446 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 447 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 448 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 449 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 450 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 451 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 452 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 453 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 454 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 455 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 456 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 457 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 458 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 459 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 460 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 461 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 462 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 463 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 464 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 465 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 466 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 467 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 468 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 469 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 470 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 471 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 472 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 473 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                       <GIC_SPI 474 IRQ_TYPE_LEVEL_HIGH>,
> > > > > >                      <GIC_SPI 475 IRQ_TYPE_LEVEL_HIGH>;
> > > > > >          clocks = <&cpg CPG_MOD R9A07G044_IA55_CLK>,
> > > > > >                        <&cpg CPG_MOD R9A07G044_IA55_PCLK>;
> > > > > >           clock-names = "clk", "pclk";
> > > > > >           power-domains = <&cpg>;
> > > > > >           resets = <&cpg R9A07G044_IA55_RESETN>;
> > > > > > };
> > > > > >
> > > > > >
> > > > > > In the hierarchal interrupt code its parsed as below:
> > > > > > on probe fetch the details:
> > > > > > range = of_get_property(np, "interrupts", &len);
> > > > > > if (!range)
> > > > > >       return -EINVAL;
> > > > > >
> > > > > > for (len /= sizeof(*range), j = 0; len >= 3; len -= 3) {
> > > > > >       if (j >= IRQC_NUM_IRQ)
> > > > > >             return -EINVAL;
> > > > > >
> > > > > >       priv->map[j].args[0] = be32_to_cpu(*range++);
> > > > > >       priv->map[j].args[1] = be32_to_cpu(*range++);
> > > > > >       priv->map[j].args[2] = be32_to_cpu(*range++);
> > > > > >       priv->map[j].args_count = 3;
> > > > > >       j++;
> > > > >
> > > > > Not sure what's wrong, but you shouldn't be doing your own parsing.
> > > > > The setup shouldn't look much different than a GPIO controller
> > > > > interrupts except you have multiple parent interrupts.
> > > > >
> > > > Sorry does that mean the IRQ domain should be chained handler and not
> > > > hierarchical? Or is it I have miss-understood.
> >
> > I guess the core DT code allocates the interrupts itself, as if the
> > interrupt controller was the interrupt producer itself (which isn't
> > the case here), bypassing the hierarchical setup altogether.
> >
> > We solved it on the MSI side by not using 'interrupts'. Either we
> > adopt a similar solution for wired interrupts, or we fix the core DT
> > code.
> >
> So maybe for now we go with your earlier suggestion of using
> "interrupt-range"? (And address the core DT in near future)
>
> Rob, is that OK with you?

No. The existing bindings are sufficient for describing what you need
to describe. If the kernel can't handle that, that's no reason for a
new binding.

The core code needs to handle all this whether it's 'interrupts' or
'interrupt-range' you are parsing. Sorry, but I really don't
understand the hierarchical stuff to provide better guidance.

Rob