Re: [RFC PATCH v3 25/35] Documentation/devicetree/bindings/sh/cpus.yaml: Add SH CPU.

[Yoshinori Sato <ysato@users.sourceforge.jp>]

On Wed, 25 Oct 2023 20:33:07 +0900,
D. Jeff Dionne wrote:
> 
> Hi Sato-san,
> 
> We must not imply that Renesas is responsible for J2, or that it is a sanctioned SH core.
> 
> J-Core has the responsibility for maintenance of those SH ISA compatible cores.
>

Yes. I know.
I intended to write about ISA compatibility.

> J.
> 
> > On Oct 25, 2023, at 20:14, Yoshinori Sato <ysato@users.sourceforge.jp> wrote:
> > 
> > On Wed, 18 Oct 2023 23:27:43 +0900,
> > Geert Uytterhoeven wrote:
> >> 
> >> Hi Sato-san,
> >> 
> >> On Sat, Oct 14, 2023 at 4:54 PM Yoshinori Sato
> >> <ysato@users.sourceforge.jp> wrote:
> >>> Renesas SuperH binding definition.
> >>> 
> >>> Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
> >> 
> >> Thanks for your patch!
> >> 
> >>> --- /dev/null
> >>> +++ b/Documentation/devicetree/bindings/sh/cpus.yaml
> >>> @@ -0,0 +1,45 @@
> >>> +# SPDX-License-Identifier: GPL-2.0
> >>> +%YAML 1.2
> >>> +---
> >>> +$id: http://devicetree.org/schemas/sh/cpus.yaml#
> >>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >>> +
> >>> +title: Renesas SuperH CPUs
> >>> +
> >>> +maintainers:
> >>> +  - Yoshinori Sato <ysato@users.sourceforge.jp>
> >>> +
> >>> +description: |+
> >>> +  The device tree allows to describe the layout of CPUs in a system through
> >>> +  the "cpus" node, which in turn contains a number of subnodes (ie "cpu")
> >>> +  defining properties for every cpu.
> >>> +
> >>> +  Bindings for CPU nodes follow the Devicetree Specification, available from:
> >>> +
> >>> +  https://www.devicetree.org/specifications/
> >>> +
> >>> +properties:
> >>> +  compatible:
> >>> +    items:
> >>> +      - enum:
> >> 
> >> Missing
> >> 
> >>    - jcore,j2
> >> 
> >>> +          - renesas,sh4
> >> 
> >> 
> >>> +      - const: renesas,sh
> >> 
> >> I see arch/sh/boot/dts/j2_mimas_v2.dts lacks the fallback to
> >> "renesas,sh", though.
> >> Is there a common base of instructions that are available on all SH cores?
> > 
> > The base instruction set is sh2.
> > Before that, there is sh1, but this is not compatible with Linux.
> > I think it would be a good idea to change this to "renesas,sh2",
> > but the SH7619 (SH2 CPU) would look like the following.
> > cpus {
> > 	cpu: cpu@0 {
> >        	compatible = "renesas,sh2", "renesas,sh2";
> >        };
> > };
> > 
> >> Missing reg property.
> >> Missing "device_type: true".
> >> 
> >>> +
> >>> +  clock-frequency:
> >>> +    $ref: /schemas/types.yaml#/definitions/uint32
> >>> +    description: |
> >>> +      CPU core clock freqency.
> >> 
> >> Perhaps a "clocks" property instead, or as an alternative?
> >> 
> >> On sh7750, you do have
> >> 
> >>    clocks = <&cpg SH7750_CPG_ICK>;
> >> 
> >>> +
> >>> +required:
> >>> +  - compatible
> >>> +
> >>> +additionalProperties: true
> >>> +
> >>> +examples:
> >>> +  - |
> >>> +        cpus {
> >> 
> >> make dt_binding_check
> >> DT_SCHEMA_FILES=Documentation/devicetree/bindings/sh/cpus.yaml:
> >> 
> >> Documentation/devicetree/bindings/sh/cpus.example.dtb: cpus:
> >> '#address-cells' is a required property
> >>        from schema $id: http://devicetree.org/schemas/cpus.yaml#
> >>        Documentation/devicetree/bindings/sh/cpus.example.dtb: cpus:
> >> '#size-cells' is a required property
> >> from schema $id: http://devicetree.org/schemas/cpus.yaml#
> >> 
> >>> +                cpu: cpu@0 {
> >>> +                      compatible = "renesas,sh4", "renesas,sh";
> >> 
> >> Documentation/devicetree/bindings/sh/cpus.example.dts:19.28-21.19:
> >> Warning (unit_address_vs_reg): /example-0/cpus/cpu@0: node has a unit
> >> name, but no reg or ranges property
> >> Documentation/devicetree/bindings/sh/cpus.example.dtb: cpus: cpu@0:
> >> 'cache-level' is a required property
> >>        from schema $id: http://devicetree.org/schemas/cpus.yaml#
> >> 
> >>> +                };
> >>> +        };
> >>> +...
> >> 
> >> Gr{oetje,eeting}s,
> >> 
> >>                        Geert
> >> 
> >> -- 
> >> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> >> 
> >> In personal conversations with technical people, I call myself a hacker. But
> >> when I'm talking to journalists I just say "programmer" or something like that.
> >>                                -- Linus Torvalds
> > 
> > -- 
> > Yosinori Sato
> 

-- 
Yosinori Sato