Re: [PATCH 4/4] dt-bindings: cache: Add docs for StarFive StarLink-500 cache controller

From: Conor Dooley
Date: Sun Mar 17 2024 - 10:59:32 EST


On Fri, Mar 15, 2024 at 10:36:07AM -0600, Rob Herring wrote:
> On Thu, Mar 14, 2024 at 02:12:05PM +0800, Joshua Yeong wrote:
> > Add DT binding documentation used by StarFive's
> > Starlink-500 cache controller.
> >
> > Signed-off-by: Joshua Yeong <joshua.yeong@xxxxxxxxxxxxxxxx>
> > ---
> > .../cache/starfive,starlink-500-cache.yaml | 62 +++++++++++++++++++
> > 1 file changed, 62 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/cache/starfive,starlink-500-cache.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/cache/starfive,starlink-500-cache.yaml b/Documentation/devicetree/bindings/cache/starfive,starlink-500-cache.yaml
> > new file mode 100644
> > index 000000000000..97ddf7db39e9
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/cache/starfive,starlink-500-cache.yaml
> > @@ -0,0 +1,62 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/cache/starfive,starlink-500-cache.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: StarFive StarLink-500 Cache Controller
> > +
> > +maintainers:
> > + - Joshua Yeong <joshua.yeong@xxxxxxxxxxxxxxxx>
> > +
> > +description:
> > + StarFive's StarLink-500 controller manages cache shared between clusters of
> > + CPU cores. The cache driver provides mechanism to perform invalidate and write
> > + back functionality to the shared memory.
>
> What a driver does is not relevant to the binding. You could describe
> what the registers control though.
>
> > +
> > +allOf:
> > + - $ref: /schemas/cache-controller.yaml#
> > +
> > +# We need a select here so we don't match all nodes with 'cache'
> > +select:
> > + properties:
> > + compatible:
> > + contains:
> > + enum:
> > + - starfive,starlink-500-cache
> > +
> > + required:
> > + - compatible
> > +
> > +properties:
> > + compatible:
> > + items:
> > + - const: starfive,starlink-500-cache
> > + - const: cache

You're also missing a soc-specific compatible here as far as I can tell,
as one of the other patches in this series specifically calls out the
JH8100 as where this cache controller is. AFAICT, "starlink-500" is the
name of the IP or of the coreplex - it's not the name of the SoC.

> > +
> > + reg:
> > + maxItems: 1
> > +
> > + cache-size: true
> > + cache-sets: true
> > + cache-block-size: true
> > + cache-level: true
> > + cache-unified: true
>
> Drop these and...
>
> > +
> > +additionalProperties: false
>
> ... use 'unevaluatedProperties' instead.
>
> > +
> > +required:
> > + - compatible
> > + - reg
>
> cache-unified should be required as I imagine the cache is always
> unified. Perhaps other properties too (cache-level already is)?

And I also suspect that a load of the values can be restricted to
specific values for that jh8100 compatible.

>
> > +
> > +examples:
> > + - |
> > + cache-controller@15000000 {
> > + compatible = "starfive,starlink-500-cache", "cache";
> > + reg = <0x15000000 0x278>;
> > + cache-block-size = <64>;
> > + cache-level = <3>;
> > + cache-sets = <8192>;
> > + cache-size = <0x400000>;
> > + cache-unified;
> > + };
> > --
> > 2.25.1
> >

Attachment: signature.asc
Description: PGP signature