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From:   Emil Renner Berthing <emil.renner.berthing@canonical.com>
In-Reply-To: <20231026-cupcake-smashing-eb150e74a17c@spud>
References: <CAJM55Z8DXDs6LT0JrTyEMp8V6BHvsjUW7aJ8Gj+fRGsasHAi_A@mail.gmail.com>
 <20231026-cupcake-smashing-eb150e74a17c@spud>
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Date:   Thu, 26 Oct 2023 07:44:54 -0700
Message-ID: <CAJM55Z-NAuGjwGXT7vMg+BCofQ8yo7Q_481LQV4zjN3ByRNxBQ@mail.gmail.com>
Subject: Re: [PATCH 3/4] dt-bindings: cache: sifive,ccache0: Add
 sifive,cache-ops property
To:     Conor Dooley <conor@kernel.org>,
        Emil Renner Berthing <emil.renner.berthing@canonical.com>
Cc:     linux-riscv@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>
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Conor Dooley wrote:
> Hey Emil,
>
> On Wed, Oct 25, 2023 at 11:56:41AM -0700, Emil Renner Berthing wrote:
> > This cache controller also supports flushing cache lines by writing
> > their address to a register. This can be used for cache management on
> > SoCs with non-coherent DMAs that predate the RISC-V Zicbom extension
> > such as the StarFive JH7100 SoC.
>
> I'm not really sure why we need the flag, is it not sufficient to
> register the cache ops on a per-compatible basis? At least for the
> jh7110

-jh7110
+jh7100

> you're always going to want them, otherwise your system is going
> to be largely non-functional, right?

That's right. I'll do it that way for v2. I guess my thinking was that this
would be easier to just add to the device trees of other platforms that might
need it. Eg. mpfs pci and jh7110 graphics.

> >
> > Signed-off-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
> > ---
> >  Documentation/devicetree/bindings/cache/sifive,ccache0.yaml | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/cache/sifive,ccache0.yaml
> > b/Documentation/devicetree/bindings/cache/sifive,ccache0.yaml
> > index 7e8cebe21584..36ae6f48ce0b 100644
> > --- a/Documentation/devicetree/bindings/cache/sifive,ccache0.yaml
> > +++ b/Documentation/devicetree/bindings/cache/sifive,ccache0.yaml
> > @@ -81,6 +81,11 @@ properties:
> >        The reference to the reserved-memory for the L2 Loosely
> > Integrated Memory region.
> >        The reserved memory node should be defined as per the bindings
> > in reserved-memory.txt.
> >
> > +  sifive,cache-ops:
> > +    type: boolean
> > +    description: |
>
> and this | is not required btw, since there's no formatting here that
> would need to be preserved.

Ah, thanks.

/Emil