Commit d8d42d47 authored by Simon Glass's avatar Simon Glass Committed by Miquel Raynal
Browse files

dt-bindings: mtd: fixed-partitions: Add alignment properties 



Add three properties for controlling alignment of partitions, aka
'entries' in fixed-partition.

For now there is no explicit mention of hierarchy, so a 'section' is
just the 'fixed-partitions' node.

These new properties are inputs to the Binman 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: default avatarSimon Glass <sjg@chromium.org>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20240412153249.100787-1-sjg@chromium.org
parent 3ef4600f

Documentation/devicetree/bindings/mtd/partitions/partition.yaml

+51 −0
Original line number Diff line number Diff line
@@ -57,6 +57,57 @@ properties: 
      user space from

    type: boolean



  align:

    $ref: /schemas/types.yaml#/definitions/uint32

    minimum: 2

    maximum: 0x80000000

    multipleOf: 2

    description:

      This sets the alignment of the entry in bytes.



      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 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

      must be a power of 2. If ‘align’ is not provided, no alignment is

      performed.



  align-size:

    $ref: /schemas/types.yaml#/definitions/uint32

    minimum: 2

    maximum: 0x80000000

    multipleOf: 2

    description:

      This sets the alignment of the entry size in bytes. It must be a power

      of 2.



      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 content of the

      entry 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

    minimum: 2

    maximum: 0x80000000

    multipleOf: 2

    description:

      This sets the alignment (in bytes) of the end of an entry with respect

      to the containing section. It must be a power of 2.



      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 content of the entry will still start at the beginning.

      But there may be padding at the end. While this does not affect the

      content of the entry 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.



if:

  not:

    required: [ reg ]