Re: [PATCH 16/21] dt-bindings: reserved-memory: introduce designated-movable-block

[Doug Berger]

On 9/14/2022 7:55 AM, Rob Herring wrote:
> On Tue, Sep 13, 2022 at 12:55:03PM -0700, Doug Berger wrote:
> > Introduce designated-movable-block.yaml to document the
> > devicetree binding for Designated Movable Block children of the
> > reserved-memory node.
>
> What is a Designated Movable Block? This patch needs to stand on its
> own.
As noted in my reply to your [PATCH 00/21] comment, my intention in 
submitting the entire patch set (and specifically PATCH 00/21]) was to 
communicate this context. Now that I believe I understand that only this 
patch should have been submitted to the devicetree-spec mailing list, I 
will strive harder to make it more self contained.

> Why does this belong or need to be in DT?
While my preferred method of declaring Designated Movable Blocks is 
through the movablecore kernel parameter, I can conceive that others may 
wish to take advantage of the reserved-memory DT nodes. In particular, 
it has the advantage that a device can claim ownership of the 
reserved-memory via device tree, which is something that has yet to be 
implemented for DMBs defined with movablecore.

> > Signed-off-by: Doug Berger <opendmb@xxxxxxxxx>
> > ---
> >   .../designated-movable-block.yaml             | 51 +++++++++++++++++++
> >   1 file changed, 51 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/reserved-memory/designated-movable-block.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/reserved-memory/designated-movable-block.yaml b/Documentation/devicetree/bindings/reserved-memory/designated-movable-block.yaml
> > new file mode 100644
> > index 000000000000..42f846069a2e
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/reserved-memory/designated-movable-block.yaml
> > @@ -0,0 +1,51 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/reserved-memory/designated-movable-block.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: /reserved-memory Designated Movable Block node binding
> > +
> > +maintainers:
> > +  - devicetree-spec@xxxxxxxxxxxxxxx
> > +
> > +allOf:
> > +  - $ref: "reserved-memory.yaml"
> > +
> > +properties:
> > +  compatible:
> > +    const: designated-movable-block
> > +    description:
> > +      This indicates a region of memory meant to be placed into
> > +      ZONE_MOVABLE.
>
> Don't put Linuxisms into bindings.
I will avoid ZONE_MOVABLE if this commit is included in V2 of this patch 
set.
> > +
> > +unevaluatedProperties: false
> > +
> > +required:
> > +  - compatible
> > +  - reusable
> > +
> > +examples:
> > +  - |
> > +      reserved-memory {
> > +          #address-cells = <0x2>;
> > +          #size-cells = <0x2>;
> > +
> > +          DMB0@10800000 {
> > +               compatible = "designated-movable-block";
> > +               reusable;
> > +               reg = <0x0 0x10800000 0x0 0x2d800000>;
> > +          };
> > +
> > +          DMB1@40000000 {
> > +               compatible = "designated-movable-block";
> > +               reusable;
> > +               reg = <0x0 0x40000000 0x0 0x30000000>;
> > +          };
> > +
> > +          DMB2@80000000 {
> > +               compatible = "designated-movable-block";
> > +               reusable;
> > +               reg = <0x0 0x80000000 0x0 0x2fc00000>;
> > +          };
> > +      };
> > --
> > 2.25.1
Thank you for the review!
-Doug