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From:   Guo Ren <guoren@kernel.org>
Date:   Sun, 24 Oct 2021 17:01:28 +0800
Message-ID: <CAJF2gTTKJXY6DAq=-ajAiTEY7hpMT1bqnvNndW=5EnD5EEP-cw@mail.gmail.com>
Subject: Re: [PATCH V5 2/3] dt-bindings: update riscv plic compatible string
To:     Anup Patel <anup@brainfault.org>
Cc:     Atish Patra <atish.patra@wdc.com>, Marc Zyngier <maz@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        =?UTF-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>,
        Rob Herring <robh@kernel.org>,
        "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        Guo Ren <guoren@linux.alibaba.com>,
        Rob Herring <robh+dt@kernel.org>,
        Palmer Dabbelt <palmerdabbelt@google.com>
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On Sun, Oct 24, 2021 at 3:35 PM Anup Patel <anup@brainfault.org> wrote:
>
> On Sun, Oct 24, 2021 at 7:03 AM <guoren@kernel.org> wrote:
> >
> > From: Guo Ren <guoren@linux.alibaba.com>
> >
> > Add the compatible string "thead,c900-plic" to the riscv plic
> > bindings to support allwinner d1 SOC which contains c906 core.
> >
> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> > Cc: Anup Patel <anup@brainfault.org>
> > Cc: Atish Patra <atish.patra@wdc.com>
> > Cc: Heiko Stuebner <heiko@sntech.de>
> > Cc: Rob Herring <robh@kernel.org>
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Cc: Palmer Dabbelt <palmerdabbelt@google.com>
> >
> > ---
> >
> > Changes since V5:
> >  - Add DT list
> >  - Fixup compatible string
> >  - Remove allwinner-d1 compatible
> >  - make dt_binding_check
> >
> > Changes since V4:
> >  - Update description in errata style
> >  - Update enum suggested by Anup, Heiko, Samuel
> >
> > Changes since V3:
> >  - Rename "c9xx" to "c900"
> >  - Add thead,c900-plic in the description section
> > ---
> >  .../interrupt-controller/sifive,plic-1.0.0.yaml   | 15 ++++++++++++---
> >  1 file changed, 12 insertions(+), 3 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml
> > index 08d5a57ce00f..18b97bfd7954 100644
> > --- a/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml
> > +++ b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml
> > @@ -35,6 +35,10 @@ description:
> >    contains a specific memory layout, which is documented in chapter 8 of the
> >    SiFive U5 Coreplex Series Manual <https://static.dev.sifive.com/U54-MC-RVCoreIP.pdf>.
> >
> > +  The thead,c900-plic couldn't complete masked irq source which has been disabled in
> > +  enable register. Add thead_plic_chip which fix up c906-plic irq source completion
> > +  problem by unmask/mask wrapper.
> > +
>
> This is an incomplete description about how T-HEAD PLIC is different from
> RISC-V PLIC.
>
> I would suggest the following:
>
> The T-HEAD C9xx SoC implements a modified/custom T-HEAD PLIC specification
> which will mask current IRQ upon read to CLAIM register and will unmask the IRQ
> upon write to CLAIM register. The thead,c900-plic compatible string
> represents the
> custom T-HEAD PLIC specification.
The patch fixup the problem that when "thead,c900-plic" couldn't
complete masked irq source which has been disabled.

This patch is different from the last one in that there is no
relationship with the auto-mask feature.

>
> Regards,
> Anup
>
> >  maintainers:
> >    - Sagar Kadam <sagar.kadam@sifive.com>
> >    - Paul Walmsley  <paul.walmsley@sifive.com>
> > @@ -42,11 +46,16 @@ maintainers:
> >
> >  properties:
> >    compatible:
> > -    items:
> > +   oneOf:
> > +    - items:
> >        - enum:
> > -          - sifive,fu540-c000-plic
> > -          - canaan,k210-plic
> > +        - sifive,fu540-c000-plic
> > +        - canaan,k210-plic
> >        - const: sifive,plic-1.0.0
> > +    - items:
> > +      - enum:
> > +        - allwinner,sun20i-d1-plic
> > +      - const: thead,c900-plic
> >
> >    reg:
> >      maxItems: 1
> > --
> > 2.25.1
> >


-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/