Hi Alper,
On Thu, 3 Aug 2023 at 14:29, Alper Nebi Yasak <alpernebiya...@gmail.com>
wrote:
>
> On 2023-07-20 22:56 +03:00, Simon Glass wrote:
> > With this version I have done with a generic name, in this case 'data',
> > as suggested by Alper Nebi Yasak. This may be controversial, but we may
> > as well have the dicussion now. I assume that there are no other
> > ongoing attempts to define the layout of firmware in devicetree.
> >
> > Signed-off-by: Simon Glass <s...@chromium.org>
> > ---
> >
> > Changes in v2:
> > - Reworked significantly based on Alper's comments
> >
> > dtschema/schemas/firmware/binman/entry.yaml | 80 +++++++++++++++++++++
> > dtschema/schemas/firmware/image.yaml | 77 ++++++++++++++++++++
> > 2 files changed, 157 insertions(+)
> > create mode 100644 dtschema/schemas/firmware/binman/entry.yaml
> > create mode 100644 dtschema/schemas/firmware/image.yaml
> >
> > diff --git a/dtschema/schemas/firmware/binman/entry.yaml
b/dtschema/schemas/firmware/binman/entry.yaml
> > new file mode 100644
> > index 0000000..d50f96d
> > --- /dev/null
> > +++ b/dtschema/schemas/firmware/binman/entry.yaml
> > @@ -0,0 +1,80 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +# Copyright 2023 Google LLC
> > +
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/firmware/image/entry.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Image entry
> > +
> > +maintainers:
> > + - Simon Glass <s...@chromium.org>
> > +
> > +description: |
> > + The entry node specifies a single entry in the firmware image.
> > +
> > + Entries have a specific type, such as "u-boot" or "atf-bl31". This
is provided
> > + using compatible = "data,<type>".
> > +
> > + Note: This definition is intended to be hierarchical, so that
entries can
> > + appear in other entries. Schema for that is TBD.
> > +
> > +properties:
> > + $nodename:
> > + pattern: "^[-a-z]+(-[0-9]+)?$"
> > +
> > + compatible:
> > + $ref: /schemas/types.yaml#/definitions/string
> > +
> > + offset:
> > + $ref: /schemas/types.yaml#/definitions/uint32
> > + description: |
> > + Provides the offset of this entry from the start of its parent
section.
> > +
> > + This may be omitted in the description provided by Binman, in
which case
> > + the value is calculated as part of image packing.
> > +
> > + size:
> > + $ref: /schemas/types.yaml#/definitions/uint32
> > + description: |
> > + Provides the size of this entry in bytes.
> > +
> > + This may be omitted in the description provided by Binman, in
which case
> > + the value is calculated as part of image packing.
>
> So AFAIU, binman will take none/one/both of "offset" and "size" as
> inputs and will pass them to the output unmodified, instead adding a
> "reg" pair of their calculated final values?
>
> Is there a schema-computational way to ensure that "reg" has to contain
> the same values as "offset" and "size"? Or is that not a restriction at
> all and "reg" overrides the others?
Probably we can do that in Python. But I don't expect people would use
'reg' in the image description as it is a pain.
>
> > +
> > + reg:
> > + description: |
> > + Defines the offset and size of this entry, with reference to its
parent
> > + image / section.
> > +
> > + Note This is typically omitted in the description provided to
Binman,
> > + since the value is calculated as part of image packing. Separate
> > + properties are provided for the size and offset of an entry, so
that it is
> > + easy to specify none, one or both. The `reg` property is the
only one that
> > + needs to be looked at once the image has been built.
> > +
>
> Do we not need a $ref for "reg"? Is there anything applicable?
Not from what I can tell. I think it is special?
>
> BTW, I'm not that familiar with device-tree interpretation, I
> occasionally saw 'reg' being used as an <offset size> pair, and was
> mostly just asking if it's appropriate.
>
> (Also TIL "ranges", and I'm imagining ranges = <0 $size 4G-$size 4G>; as
> an end-at-4gb replacement/generalization :P, but I know, later, later.)
Right, that is an x86-ism but is pretty helpful as it is otherwise widely
confusing to deal with these addresses.
>
> > +required:
> > + - compatible
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > + firmware {
> > + image {
> > + compatible = "data,image";
> > + #address-cells = <1>;
> > + $size-cells = <1>;
> > +
> > + u-boot@0 {
> > + compatible = "data,u-boot";
> > + reg = <0 0xa0000>;
> > + };
> > +
> > + atf-bl31@0x100000 {
> > + compatible = "data,atf-bl31";
> > + reg = <0x100000 0x20000>;
> > + };
> > + };
> > + };
> > diff --git a/dtschema/schemas/firmware/image.yaml
b/dtschema/schemas/firmware/image.yaml
> > new file mode 100644
> > index 0000000..949b067
> > --- /dev/null
> > +++ b/dtschema/schemas/firmware/image.yaml
> > @@ -0,0 +1,77 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +# Copyright 2023 Google LLC
> > +
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/firmware/image.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Binman firmware layout
> > +
> > +maintainers:
> > + - Simon Glass <s...@chromium.org>
> > +
> > +description: |
> > + The image node provides a layout for firmware, used when packaging
firmware
> > + from multiple projects. For now it just supports a very simple set of
> > + features, as a starting point for discussion.
> > +
> > + The Binman tool processes this node to produce a final image which
can be
> > + loaded into suitable storage device. Documentation is at:
> > +
> > + https://u-boot.readthedocs.io/en/latest/develop/package/binman.html
> > +
> > + The current image-description format is here:
> > +
> > +
https://u-boot.readthedocs.io/en/latest/develop/package/binman.html#image-description-format
> > +
> > + It is desirable to reference the image from the storage-device node,
perhaps
> > + using an image-desc property:
> > +
> > + spiflash@0 {
> > + compatible = "spidev", "jedec,spi-nor";
> > + image-desc = <&image>;
>
> Bikeshedding, but maybe "layout" or "data,layout" would be nicer.
OK
>
> > + };
> > +
> > + Note that the intention is to change Binman to use whatever schema
is agreed
> > + here.
> > +
> > +properties:
> > + $nodename:
> > + const: binman
>
> Doesn't match the example, and I guess you mean "^[-a-z]+(-[0-9]+)?$"
> like the entry one.
Right.
>
> > +
> > + compatible:
> > + const: data,image
> > +
> > + "#address-cells":
> > + const: 1
> > +
> > + "#size-cells":
> > + const: 1
> > +
> > +required:
> > + - compatible
> > + - "#address-cell"
> > + - "#size-cells"
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > + firmware {
> > + image {
> > + compatible = "data,image";
> > + #address-cells = <1>;
> > + $size-cells = <1>;
> > +
> > + u-boot@0 {
> > + compatible = "data,u-boot";
> > + reg = <0 0xa0000>;
> > + };
> > +
> > + atf-bl31@0x100000 {
> > + compatible = "data,atf-bl31";
> > + reg = <0x100000 0x20000>;
> > + };
> > + };
> > + };
Regards,
Simon
