2019-10-09 23:48:02

by Rob Herring (Arm)

[permalink] [raw]
Subject: [PATCH v2] dt-bindings: riscv: Fix CPU schema errors

Fix the errors in the RiscV CPU DT schema:

Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: 'timebase-frequency' is a required property
Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@1: 'timebase-frequency' is a required property
Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: compatible:0: 'riscv' is not one of ['sifive,rocket0', 'sifive,e5', 'sifive,e51', 'sifive,u54-mc', 'sifive,u54', 'sifive,u5']
Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: compatible: ['riscv'] is too short
Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: 'timebase-frequency' is a required property

The DT spec allows for 'timebase-frequency' to be in 'cpu' or 'cpus' node
and RiscV is doing nothing special with it, so just drop the definition
here and don't make it required.

Fixes: 4fd669a8c487 ("dt-bindings: riscv: convert cpu binding to json-schema")
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: [email protected]
Signed-off-by: Rob Herring <[email protected]>
---
.../devicetree/bindings/riscv/cpus.yaml | 28 ++++++++-----------
1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/Documentation/devicetree/bindings/riscv/cpus.yaml b/Documentation/devicetree/bindings/riscv/cpus.yaml
index b261a3015f84..925b531767bf 100644
--- a/Documentation/devicetree/bindings/riscv/cpus.yaml
+++ b/Documentation/devicetree/bindings/riscv/cpus.yaml
@@ -24,15 +24,17 @@ description: |

properties:
compatible:
- items:
- - enum:
- - sifive,rocket0
- - sifive,e5
- - sifive,e51
- - sifive,u54-mc
- - sifive,u54
- - sifive,u5
- - const: riscv
+ oneOf:
+ - items:
+ - enum:
+ - sifive,rocket0
+ - sifive,e5
+ - sifive,e51
+ - sifive,u54-mc
+ - sifive,u54
+ - sifive,u5
+ - const: riscv
+ - const: riscv # Simulator only
description:
Identifies that the hart uses the RISC-V instruction set
and identifies the type of the hart.
@@ -66,13 +68,6 @@ properties:
insensitive, letters in the riscv,isa string must be all
lowercase to simplify parsing.

- timebase-frequency:
- type: integer
- minimum: 1
- description:
- Specifies the clock frequency of the system timer in Hz.
- This value is common to all harts on a single system image.
-
interrupt-controller:
type: object
description: Describes the CPU's local interrupt controller
@@ -93,7 +88,6 @@ properties:

required:
- riscv,isa
- - timebase-frequency
- interrupt-controller

examples:
--
2.20.1


2019-10-10 00:10:06

by Paul Walmsley

[permalink] [raw]
Subject: Re: [PATCH v2] dt-bindings: riscv: Fix CPU schema errors

On Wed, 9 Oct 2019, Rob Herring wrote:

> Fix the errors in the RiscV CPU DT schema:
>
> Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: 'timebase-frequency' is a required property
> Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@1: 'timebase-frequency' is a required property
> Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: compatible:0: 'riscv' is not one of ['sifive,rocket0', 'sifive,e5', 'sifive,e51', 'sifive,u54-mc', 'sifive,u54', 'sifive,u5']
> Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: compatible: ['riscv'] is too short
> Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: 'timebase-frequency' is a required property
>
> The DT spec allows for 'timebase-frequency' to be in 'cpu' or 'cpus' node
> and RiscV is doing nothing special with it, so just drop the definition
> here and don't make it required.

The RISC-V kernel code does in fact parse it and use it, and we currently
rely on it being under /cpus:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/riscv/kernel/time.c#n19

The RISC-V user ISA specification also constrains the timebase-frequency
to be the same across all CPUs, in section 10.1:

https://github.com/riscv/riscv-isa-manual/releases/download/draft-20190608-f467e5d/riscv-spec.pdf

So the right thing is to require 'timebase-frequency' at /cpus, and forbid
it in the individual CPU nodes.

>
> Fixes: 4fd669a8c487 ("dt-bindings: riscv: convert cpu binding to json-schema")
> Cc: Paul Walmsley <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>
> Cc: Albert Ou <[email protected]>
> Cc: [email protected]
> Signed-off-by: Rob Herring <[email protected]>
> ---
> .../devicetree/bindings/riscv/cpus.yaml | 28 ++++++++-----------
> 1 file changed, 11 insertions(+), 17 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/riscv/cpus.yaml b/Documentation/devicetree/bindings/riscv/cpus.yaml
> index b261a3015f84..925b531767bf 100644
> --- a/Documentation/devicetree/bindings/riscv/cpus.yaml
> +++ b/Documentation/devicetree/bindings/riscv/cpus.yaml
> @@ -24,15 +24,17 @@ description: |
>
> properties:
> compatible:
> - items:
> - - enum:
> - - sifive,rocket0
> - - sifive,e5
> - - sifive,e51
> - - sifive,u54-mc
> - - sifive,u54
> - - sifive,u5
> - - const: riscv
> + oneOf:
> + - items:
> + - enum:
> + - sifive,rocket0
> + - sifive,e5
> + - sifive,e51
> + - sifive,u54-mc
> + - sifive,u54
> + - sifive,u5
> + - const: riscv
> + - const: riscv # Simulator only
> description:
> Identifies that the hart uses the RISC-V instruction set
> and identifies the type of the hart.
> @@ -66,13 +68,6 @@ properties:
> insensitive, letters in the riscv,isa string must be all
> lowercase to simplify parsing.
>
> - timebase-frequency:
> - type: integer
> - minimum: 1
> - description:
> - Specifies the clock frequency of the system timer in Hz.
> - This value is common to all harts on a single system image.
> -
> interrupt-controller:
> type: object
> description: Describes the CPU's local interrupt controller
> @@ -93,7 +88,6 @@ properties:
>
> required:
> - riscv,isa
> - - timebase-frequency
> - interrupt-controller
>
> examples:
> --
> 2.20.1
>
>


- Paul

2019-10-10 12:48:21

by Rob Herring (Arm)

[permalink] [raw]
Subject: Re: [PATCH v2] dt-bindings: riscv: Fix CPU schema errors

On Wed, Oct 9, 2019 at 7:08 PM Paul Walmsley <[email protected]> wrote:
>
> On Wed, 9 Oct 2019, Rob Herring wrote:
>
> > Fix the errors in the RiscV CPU DT schema:
> >
> > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: 'timebase-frequency' is a required property
> > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@1: 'timebase-frequency' is a required property
> > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: compatible:0: 'riscv' is not one of ['sifive,rocket0', 'sifive,e5', 'sifive,e51', 'sifive,u54-mc', 'sifive,u54', 'sifive,u5']
> > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: compatible: ['riscv'] is too short
> > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: 'timebase-frequency' is a required property
> >
> > The DT spec allows for 'timebase-frequency' to be in 'cpu' or 'cpus' node
> > and RiscV is doing nothing special with it, so just drop the definition
> > here and don't make it required.
>
> The RISC-V kernel code does in fact parse it and use it, and we currently
> rely on it being under /cpus:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/riscv/kernel/time.c#n19
>
> The RISC-V user ISA specification also constrains the timebase-frequency
> to be the same across all CPUs, in section 10.1:
>
> https://github.com/riscv/riscv-isa-manual/releases/download/draft-20190608-f467e5d/riscv-spec.pdf
>
> So the right thing is to require 'timebase-frequency' at /cpus, and forbid
> it in the individual CPU nodes.

Yes, but this schema only deals with 'cpu' nodes and we can't check
/cpus here. We'd need to write another schema matching on a child cpu
node having a RiscV compatible.

I can change this to 'timebase-frequency: false' to ban it here. That
doesn't add too much as any undefined name is still allowed such as
'timbase-frequency'. There's a way to address this in json-schema
draft8 with 'unevaluatedProperties', but that's not ready yet.

Rob

2019-10-10 18:35:59

by Paul Walmsley

[permalink] [raw]
Subject: Re: [PATCH v2] dt-bindings: riscv: Fix CPU schema errors

On Thu, 10 Oct 2019, Rob Herring wrote:

> On Wed, Oct 9, 2019 at 7:08 PM Paul Walmsley <[email protected]> wrote:
> >
> > On Wed, 9 Oct 2019, Rob Herring wrote:
> >
> > > Fix the errors in the RiscV CPU DT schema:
> > >
> > > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: 'timebase-frequency' is a required property
> > > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@1: 'timebase-frequency' is a required property
> > > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: compatible:0: 'riscv' is not one of ['sifive,rocket0', 'sifive,e5', 'sifive,e51', 'sifive,u54-mc', 'sifive,u54', 'sifive,u5']
> > > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: compatible: ['riscv'] is too short
> > > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: 'timebase-frequency' is a required property
> > >
> > > The DT spec allows for 'timebase-frequency' to be in 'cpu' or 'cpus' node
> > > and RiscV is doing nothing special with it, so just drop the definition
> > > here and don't make it required.
> >
> > The RISC-V kernel code does in fact parse it and use it, and we currently
> > rely on it being under /cpus:
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/riscv/kernel/time.c#n19
> >
> > The RISC-V user ISA specification also constrains the timebase-frequency
> > to be the same across all CPUs, in section 10.1:
> >
> > https://github.com/riscv/riscv-isa-manual/releases/download/draft-20190608-f467e5d/riscv-spec.pdf
> >
> > So the right thing is to require 'timebase-frequency' at /cpus, and forbid
> > it in the individual CPU nodes.
>
> Yes, but this schema only deals with 'cpu' nodes and we can't check
> /cpus here. We'd need to write another schema matching on a child cpu
> node having a RiscV compatible.
>
> I can change this to 'timebase-frequency: false' to ban it here.

Sounds good to me. (Might catch the occasional mistake.) With that
change, the resulting patch would be

Acked-by: Paul Walmsley <[email protected]> # for arch/riscv

and thanks indeed for cleaning this up.

> That doesn't add too much as any undefined name is still allowed such as
> 'timbase-frequency'. There's a way to address this in json-schema draft8
> with 'unevaluatedProperties', but that's not ready yet.

OK


- Paul