Re: [PATCH v4 3/3] dt-bindings: mtd: binman-partitions: Add alignment properties

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 sjg@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