[PATCH] dt-bindings: riscv: firmware: Add OpenSBI configuration binding

[Conor Dooley]

On Wed, Aug 19, 2026 at 06:03:12PM +0100, Conor Dooley wrote:
> On Wed, Aug 19, 2026 at 05:04:11PM +0800, Yaxing Guo wrote:
> > From: yangyinglu <yangyinglu at bosc.cn>
> > 
> > Add a Devicetree binding for OpenSBI configuration data in the
> > chosen node, including the cold-boot-harts property.
> > 
> > OpenSBI supports describing certain Generic Platform configurations in
> > the device tree passed by the previous boot stage. The OpenSBI source
> > tree documents the `opensbi,config` node and provides the corresponding
> > device tree parsing flow.
> > 
> > The `/chosen/opensbi-config` node can be used to configure OpenSBI,
> > including the set of harts permitted to perform a cold boot through the
> > `cold-boot-harts` property. OpenSBI parses this node during the boot
> > phase and removes it from the device tree after cold boot.
> > 
> > Add the Devicetree binding for this OpenSBI configuration node to
> > document the supported `compatible` and `cold-boot-harts` properties.
> > 
> > Signed-off-by: yangyinglu <yangyinglu at bosc.cn>
> > ---
> >  .../bindings/firmware/opensbi,config.yaml     | 38 +++++++++++++++++++
> >  1 file changed, 38 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/firmware/opensbi,config.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/firmware/opensbi,config.yaml b/Documentation/devicetree/bindings/firmware/opensbi,config.yaml
> > new file mode 100644
> > index 000000000000..86b1e1e673a8
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/firmware/opensbi,config.yaml
> > @@ -0,0 +1,38 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/firmware/opensbi,config.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: OpenSBI Firmware Configuration
> > +
> > +maintainers:
> 
> You probably should've waited for a response to your question about who
> should maintain it before sending, becuase I am not entirely sure this
> software configuration node should be documented or if the maintainers
> of opensbi would want it to be.

And to quote Anup:
| The opensbi configuration is all under "/chosen" DT node so I am
| not sure if we should have related bindings under Linux sources.
| 
| Other projects (such as U-boot or Xen) who use "/chosen" DT node
| also don't have their bindings under Linux sources.

So this is a nack from me on that basis, sorry. Did you have some user
for this that could change my mind?

Thanks,
Conor.

> 
> Cheers,
> Conor.
> 
> > +
> > +description: |
> > +  OpenSBI configuration data passed in the chosen node.
> > +
> > +properties:
> > +  compatible:
> > +    const: opensbi,config
> > +
> > +  cold-boot-harts:
> > +    $ref: /schemas/types.yaml#/definitions/phandle-array
> > +    description:
> > +      List of hart CPU nodes selected as cold boot harts by OpenSBI.
> > +
> > +required:
> > +  - compatible
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    / {
> > +        chosen {
> > +            opensbi-config {
> > +                compatible = "opensbi,config";
> > +                cold-boot-harts = <&cpu0>;
> > +            };
> > +        };
> > +    };
> > +...
> > -- 
> > 2.43.0
> > 


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