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From:   Simon Glass <sjg@chromium.org>
Date:   Fri, 8 Dec 2023 10:46:51 -0700
Message-ID: <CAPnjgZ2i4gvgiUeHPOfHuOdBooV4e=QQEq6iMo0JbDwOS6dCwA@mail.gmail.com>
Subject: Re: [PATCH v6 1/3] dt-bindings: mtd: partitions: Add binman compatible
To:     Rob Herring <robh@kernel.org>
Cc:     devicetree@vger.kernel.org,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        linux-mtd@lists.infradead.org, Tom Rini <trini@konsulko.com>,
        Michael Walle <mwalle@kernel.org>,
        U-Boot Mailing List <u-boot@lists.denx.de>,
        Conor Dooley <conor+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Pratyush Yadav <ptyadav@amazon.de>,
        =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= <rafal@milecki.pl>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-kernel@vger.kernel.org
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Hi Rob,

On Fri, 8 Dec 2023 at 08:00, Rob Herring <robh@kernel.org> wrote:
>
> 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.

No, they are the same node. I do want the extra information to stick
around. So long as it is compatible with fixed-partition as well, this
should work OK.

Regards,
SImon