[RFC PATCH v3 1/2] dt-bindings: cache: r9a07g043f-l2-cache: Add DT binding documentation for L2 cache controller

[Lad, Prabhakar]

Hi Rob,

Thank you for the review.

On Fri, Oct 21, 2022 at 3:10 AM Rob Herring <robh at kernel.org> wrote:
>
> On Wed, Oct 19, 2022 at 11:02:41PM +0100, Prabhakar wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>
> >
> > Add DT binding documentation for L2 cache controller found on RZ/Five SoC.
> >
> > The Renesas RZ/Five microprocessor includes a RISC-V CPU Core (AX45MP
> > Single) from Andes. The AX45MP core has an L2 cache controller, this patch
> > describes the L2 cache block.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>
> > ---
> >  .../cache/andestech,ax45mp-cache.yaml         | 125 ++++++++++++++++++
> >  .../cache/andestech,ax45mp-cache.h            |  38 ++++++
> >  2 files changed, 163 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/cache/andestech,ax45mp-cache.yaml
> >  create mode 100644 include/dt-bindings/cache/andestech,ax45mp-cache.h
> >
> > diff --git a/Documentation/devicetree/bindings/cache/andestech,ax45mp-cache.yaml b/Documentation/devicetree/bindings/cache/andestech,ax45mp-cache.yaml
> > new file mode 100644
> > index 000000000000..4c86a15bda5f
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/cache/andestech,ax45mp-cache.yaml
> > @@ -0,0 +1,125 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +# Copyright (C) 2022 Renesas Electronics Corp.
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/cache/andestech,ax45mp-cache.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Andestech AX45MP L2 Cache Controller
> > +
> > +maintainers:
> > +  - Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>
> > +
> > +description:
> > +  A level-2 cache (L2C) is used to improve the system performance by providing
> > +  a larger amount of cache line entries and reasonable access delays. The L2C
> > +  is shared between cores, and a non-inclusive non-exclusive policy is used.
> > +
> > +select:
> > +  properties:
> > +    compatible:
> > +      contains:
> > +        enum:
> > +          - andestech,ax45mp-cache
> > +
> > +  required:
> > +    - compatible
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +      - const: andestech,ax45mp-cache
> > +      - const: cache
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  cache-line-size:
> > +    const: 64
> > +
> > +  cache-level:
> > +    const: 2
> > +
> > +  cache-sets:
> > +    const: 1024
> > +
> > +  cache-size:
> > +    enum: [131072, 262144, 524288, 1048576, 2097152]
> > +
> > +  cache-unified: true
> > +
> > +  next-level-cache: true
> > +
> > +  andestech,pma-regions:
> > +    $ref: /schemas/types.yaml#/definitions/uint32-matrix
> > +    minItems: 1
> > +    maxItems: 16
>
> What is the inner dimension of the matrix?
>
> items:
>   minItems: ?
>   maxItems: ?
>
minItems = maxItems = 6

i.e. the first two entries are the address, next two is the size and
last two is the flag.
<0x0 0x58000000 0x0 0x08000000 0x0 (AX45MP_PMACFG_ETYP_NAPOT |
AX45MP_PMACFG_MTYP_MEM_NON_CACHE_BUF)>;
                                                          ^^ This is
dummy and always be 0x0

Is the above OK?

> > +    description: Optional array of memory regions to be set as non-cacheable
> > +                 bufferable regions which will be setup in the PMA.
> > +
> > +  andestech,inst-prefetch:
> > +    description: Instruction prefetch depth
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    enum: [ 0, 1, 2, 3 ]
> > +
> > +  andestech,data-prefetch:
> > +    description: Data prefetch depth
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    enum: [ 0, 1, 2, 3 ]
> > +
> > +  andestech,tag-ram-ctl:
> > +    description: Tag RAM output cycle. First tuple indicates output cycle and the
> > +      second tuple indicates setup cycle.
> > +    $ref: /schemas/types.yaml#/definitions/uint8-array
> > +    items:
> > +      - minimum: 0
> > +        maximum: 2
> > +      - minimum: 0
> > +        maximum: 2
>
> maxItems: 2
> items:
>   maximum: 2
>
> 'items' without the '-' applies to all items.
>
> And the minimum is already 0.
>
Thanks for the suggestion, I'll fix it in the next version.

> > +
> > +  andestech,data-ram-ctl:
> > +    description: Data RAM output cycle. First tuple indicates output cycle and the
> > +      second tuple indicates setup cycle.
> > +    $ref: /schemas/types.yaml#/definitions/uint8-array
> > +    items:
> > +      - minimum: 0
> > +        maximum: 2
> > +      - minimum: 0
> > +        maximum: 2
>
> Same here.
>
Ditto.

Cheers,
Prabhakar