Re: [PATCH v6 1/3] dt-bindings: mtd: partitions: Add binman compatible

[Rob Herring <robh@kernel.org>]

On Thu, Nov 16, 2023 at 10:28:50AM -0700, Simon Glass wrote:
> Add a compatible string for binman, so we can extend fixed-partitions
> in various ways.
> 
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
> 
> (no changes since v5)
> 
> Changes in v5:
> - Add #address/size-cells and parternProperties
> - Drop $ref to fixed-partitions.yaml
> - Drop 'select: false'
> 
> Changes in v4:
> - Change subject line
> 
> Changes in v3:
> - Drop fixed-partition additional compatible string
> - Drop fixed-partitions from the example
> - Mention use of compatible instead of label
> 
> Changes in v2:
> - Drop mention of 'enhanced features' in fixed-partitions.yaml
> - Mention Binman input and output properties
> - Use plain partition@xxx for the node name
> 
>  .../bindings/mtd/partitions/binman.yaml       | 68 +++++++++++++++++++
>  .../bindings/mtd/partitions/partitions.yaml   |  1 +
>  MAINTAINERS                                   |  5 ++
>  3 files changed, 74 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mtd/partitions/binman.yaml
> 
> diff --git a/Documentation/devicetree/bindings/mtd/partitions/binman.yaml b/Documentation/devicetree/bindings/mtd/partitions/binman.yaml
> new file mode 100644
> index 000000000000..329217550a98
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/partitions/binman.yaml
> @@ -0,0 +1,68 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright 2023 Google LLC
> +
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mtd/partitions/binman.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Binman firmware layout
> +
> +maintainers:
> +  - Simon Glass <sjg@chromium.org>
> +
> +description: |
> +  The binman node provides a layout for firmware, used when packaging firmware
> +  from multiple projects. It is based on fixed-partitions, with some
> +  extensions, but uses 'compatible' to indicate the contents of the node, to
> +  avoid perturbing or confusing existing installations which use 'label' for a
> +  particular purpose.
> +
> +  Binman supports properties used as inputs to the firmware-packaging process,
> +  such as those which control alignment of partitions. This binding addresses
> +  these 'input' properties. For example, it is common for the 'reg' property
> +  (an 'output' property) to be set by Binman, based on the alignment requested
> +  in the input.
> +
> +  Once processing is complete, input properties have mostly served their
> +  purpose, at least until the firmware is repacked later, e.g. due to a
> +  firmware update. The 'fixed-partitions' binding should provide enough
> +  information to read the firmware at runtime, including decompression if
> +  needed.

How is this going to work exactly? binman reads these nodes and then 
writes out 'fixed-partitions' nodes. But then you've lost the binman 
specifc parts needed for repacking.

Rob