On Mon, Oct 09, 2023 at 04:04:15PM -0600, Simon Glass wrote:
> Add three properties for controlling alignment of partitions, aka
> 'entries' in binman.
>
> For now there is no explicit mention of hierarchy, so a 'section' is
> just the 'binman' node.
>
> These new properties are inputs to the packaging process, but are also
> needed if the firmware is repacked, to ensure that alignment
> constraints are not violated. Therefore they are provided as part of
> the schema.
>
> Signed-off-by: Simon Glass <s...@chromium.org>
> ---
>
> (no changes since v2)
>
> Changes in v2:
> - Fix 'a' typo in commit message
>
> .../mtd/partitions/binman-partition.yaml | 39 +++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git
> a/Documentation/devicetree/bindings/mtd/partitions/binman-partition.yaml
> b/Documentation/devicetree/bindings/mtd/partitions/binman-partition.yaml
> index 35a320359ec1..8e8a3b6d4d14 100644
> --- a/Documentation/devicetree/bindings/mtd/partitions/binman-partition.yaml
> +++ b/Documentation/devicetree/bindings/mtd/partitions/binman-partition.yaml
> @@ -28,6 +28,42 @@ properties:
> - const: u-boot # u-boot.bin from U-Boot project
> - const: atf-bl31 # bl31.bin or bl31.elf from TF-A project
>
> + align:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description:
> + This sets the alignment of the entry. The entry offset is adjusted
> + so that the entry starts on an aligned boundary within the containing
> + section or image. For example ‘align = <16>’ means that the entry will
> + start on a 16-byte boundary. This may mean that padding is added before
Only your example defines that alignment is in bytes.
> + the entry. The padding is part of the containing section but is not
> + included in the entry, meaning that an empty space may be created
> before
> + the entry starts. Alignment should be a power of 2. If ‘align’ is not
> + provided, no alignment is performed.
Would be nice to have some constraints. Unfortunately, no way to say
'power of 2' in json-schema (we could add something possibly), so the
only way is:
enum: [ 2, 4, 8, 16, 32, 64, ... ]
Kind of verbose if we add all 31 possibilities...
Could also do this:
minium: 2
maximum: 0x80000000
multipleOf: 2
> +
> + align-size:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description:
> + This sets the alignment of the entry size. For example, to ensure
> + that the size of an entry is a multiple of 64 bytes, set this to 64.
> + While this does not affect the contents of the entry within binman
> + itself (the padding is performed only when its parent section is
> + assembled), the end result is that the entry ends with the padding
> + bytes, so may grow. If ‘align-size’ is not provided, no alignment is
> + performed.
> +
> + align-end:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description:
> + This sets the alignment of the end of an entry with respect to the
> + containing section. Some entries require that they end on an alignment
> + boundary, regardless of where they start. This does not move the start
> + of the entry, so the contents of the entry will still start at the
> + beginning. But there may be padding at the end. While this does not
> + affect the contents of the entry within binman itself (the padding is
> + performed only when its parent section is assembled), the end result is
> + that the entry ends with the padding bytes, so may grow. If ‘align-end’
> + is not provided, no alignment is performed.
> +
> additionalProperties: false
>
> examples:
> @@ -40,10 +76,13 @@ examples:
> partition@100000 {
> compatible = "u-boot";
> reg = <0x100000 0xf00000>;
> + align-size = <0x1000>;
> + align-end = <0x10000>;
> };
>
> partition@200000 {
> compatible = "atf-bl31";
> reg = <0x200000 0x100000>;
> + align = <0x4000>;
> };
> };
> --
> 2.42.0.609.gbb76f46606-goog
>
