RE: [RESEND PATCH v2 1/1] dt-bindings: riscv: sifive-l2-cache: convert bindings to json-schema

[Sagar Kadam]

Hello Rob,

> -----Original Message-----
> From: Rob Herring <robh@xxxxxxxxxx>
> Sent: Monday, September 14, 2020 11:30 PM
> To: Sagar Kadam <sagar.kadam@xxxxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-riscv@xxxxxxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; Paul Walmsley ( Sifive)
> <paul.walmsley@xxxxxxxxxx>; palmer@xxxxxxxxxxx;
> aou@xxxxxxxxxxxxxxxxx; Yash Shah <yash.shah@xxxxxxxxxxxx>
> Subject: Re: [RESEND PATCH v2 1/1] dt-bindings: riscv: sifive-l2-cache:
> convert bindings to json-schema
> 
> [External Email] Do not click links or attachments unless you recognize the
> sender and know the content is safe
> 
> On Fri, Aug 28, 2020 at 10:25:43PM +0530, Sagar Kadam wrote:
> > Convert the device tree bindings for the SiFive's FU540-C000 SoC's L2
> Cache
> > controller to YAML format.
> >
> > Signed-off-by: Sagar Kadam <sagar.kadam@xxxxxxxxxx>
> > ---
> >  .../devicetree/bindings/riscv/sifive-l2-cache.txt  | 51 ------------
> >  .../devicetree/bindings/riscv/sifive-l2-cache.yaml | 92
> ++++++++++++++++++++++
> >  2 files changed, 92 insertions(+), 51 deletions(-)
> >  delete mode 100644 Documentation/devicetree/bindings/riscv/sifive-l2-
> cache.txt
> >  create mode 100644 Documentation/devicetree/bindings/riscv/sifive-l2-
> cache.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/riscv/sifive-l2-cache.txt
> b/Documentation/devicetree/bindings/riscv/sifive-l2-cache.txt
> > deleted file mode 100644
> > index 73d8f19..0000000
> > --- a/Documentation/devicetree/bindings/riscv/sifive-l2-cache.txt
> > +++ /dev/null
> > @@ -1,51 +0,0 @@
> > -SiFive L2 Cache Controller
> > ---------------------------
> > -The SiFive Level 2 Cache Controller is used to provide access to fast
> copies
> > -of memory for masters in a Core Complex. The Level 2 Cache Controller
> also
> > -acts as directory-based coherency manager.
> > -All the properties in ePAPR/DeviceTree specification applies for this
> platform
> > -
> > -Required Properties:
> > ---------------------
> > -- compatible: Should be "sifive,fu540-c000-ccache" and "cache"
> > -
> > -- cache-block-size: Specifies the block size in bytes of the cache.
> > -  Should be 64
> > -
> > -- cache-level: Should be set to 2 for a level 2 cache
> > -
> > -- cache-sets: Specifies the number of associativity sets of the cache.
> > -  Should be 1024
> > -
> > -- cache-size: Specifies the size in bytes of the cache. Should be 2097152
> > -
> > -- cache-unified: Specifies the cache is a unified cache
> > -
> > -- interrupts: Must contain 3 entries (DirError, DataError and DataFail
> signals)
> > -
> > -- reg: Physical base address and size of L2 cache controller registers map
> > -
> > -Optional Properties:
> > ---------------------
> > -- next-level-cache: phandle to the next level cache if present.
> > -
> > -- memory-region: 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
> > -
> > -
> > -Example:
> > -
> > -     cache-controller@2010000 {
> > -             compatible = "sifive,fu540-c000-ccache", "cache";
> > -             cache-block-size = <64>;
> > -             cache-level = <2>;
> > -             cache-sets = <1024>;
> > -             cache-size = <2097152>;
> > -             cache-unified;
> > -             interrupt-parent = <&plic0>;
> > -             interrupts = <1 2 3>;
> > -             reg = <0x0 0x2010000 0x0 0x1000>;
> > -             next-level-cache = <&L25 &L40 &L36>;
> > -             memory-region = <&l2_lim>;
> > -     };
> > diff --git a/Documentation/devicetree/bindings/riscv/sifive-l2-cache.yaml
> b/Documentation/devicetree/bindings/riscv/sifive-l2-cache.yaml
> > new file mode 100644
> > index 0000000..e14c8c6
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/riscv/sifive-l2-cache.yaml
> > @@ -0,0 +1,92 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +# Copyright (C) 2020 SiFive, Inc.
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/riscv/sifive-l2-cache.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: SiFive L2 Cache Controller
> > +
> > +maintainers:
> > +  - Sagar Kadam <sagar.kadam@xxxxxxxxxx>
> > +  - Yash Shah <yash.shah@xxxxxxxxxx>
> > +  - Paul Walmsley  <paul.walmsley@xxxxxxxxxx>
> > +
> > +description:
> > +  The SiFive Level 2 Cache Controller is used to provide access to fast
> copies
> > +  of memory for masters in a Core Complex. The Level 2 Cache Controller
> also
> > +  acts as directory-based coherency manager.
> > +  All the properties in ePAPR/DeviceTree specification applies for this
> platform.
> > +
> > +allOf:
> > +  - $ref: /schemas/cache-controller.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +     - enum:
> > +        - sifive,fu540-c000-ccache
> > +    description: |
> > +      Should have "sifive,<soc>-cache" and "cache".
> 
> That's not what the schema describes or the example has (the 'cache'
> fallback).
> 
Thanks for your suggestions. 
I see that if we include the standard 'cache' property here, it injects  error's in other yaml's as reported here [1]
In plain txt format of this binding the standard "cache" property is mentioned to be also included along with soc specific compatible string.

Please correct me if I am wrong here:
So in order to retain the earlier description as Should have "sifive,<soc>-cache" and "cache",  I excluded "cache" property from example
as I assumed it is implied for cacheinfo infrastructure to work properly.
I will retain the earlier description (from.txt) which was "sifive,fu540-c000-ccache" and "cache"
[1] https://patchwork.ozlabs.org/patch/1350111

> > +
> > +  cache-block-size:
> > +    const: 64
> > +
> > +  cache-level:
> > +    const: 2
> > +
> > +  cache-sets:
> > +    const: 1024
> > +
> > +  cache-size:
> > +    const: 2097152
> > +
> > +  cache-unified: true
> > +
> > +  interrupts:
> > +    description: |
> > +      Must contain entries for DirError, DataError and DataFail signals.
> > +    minItems: 1
> 
> The old doc said must have 3 entries.
Will rectify.
> 
> > +    maxItems: 3
> > +
> > +  reg:
> > +    maxItems: 1
> > +    description: address of cache controller's registers.
> 
> Drop this.
> 
Will drop the reg description in next version.
> > +
> > +
> 
> One blank line please.
> 
Will address this as well.

> > +  next-level-cache:
> > +    description: |
> > +      Phandle to the next level cache if present.
> 
> No need to re-describe common properties unless you have something
> unique to this device to say. Just:
> 
> 'next-level-cache: true'
> 

Ok. I will remove un-necessary description.

Thanks & BR,
Sagar

> > +
> > +  memory-region:
> > +    description: |
> > +      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.
> > +
> > +additionalProperties: false
> > +
> > +required:
> > +  - compatible
> > +  - cache-block-size
> > +  - cache-level
> > +  - cache-sets
> > +  - cache-size
> > +  - cache-unified
> > +  - interrupts
> > +  - reg
> > +
> > +examples:
> > +  - |
> > +    cache-controller@2010000 {
> > +        compatible = "sifive,fu540-c000-ccache";
> > +        cache-block-size = <64>;
> > +        cache-level = <2>;
> > +        cache-sets = <1024>;
> > +        cache-size = <2097152>;
> > +        cache-unified;
> > +        reg = <0x2010000 0x1000>;
> > +        interrupt-parent = <&plic0>;
> > +        interrupts = <1 2 3>;
> > +        next-level-cache = <&L25>;
> > +        memory-region = <&l2_lim>;
> > +    };
> > --
> > 2.7.4
> >