[PATCH v6 1/3] dt-bindings: mtd: amlogic,meson-nand: support fields for boot ROM code

[Arseniy Krasnov]

Changelog:

v5 -> v6:

* Update description in 'yaml' and commit message by adding more details
  about such special Meson mode. R-b was removed so.

Thanks, Arseniy

On 08.05.2024 02:09, Arseniy Krasnov wrote:
> Boot ROM code on Meson requires that some pages on NAND must be written
> in special mode: "short" ECC mode where each block is 384 bytes and
> scrambling mode is on. Such pages are located on the chip in the
> following way (for example):
> 
> [ p0 ][ p1 ][ p2 ][ p3 ][ p4 ][ p5 ][ p6 ][ p7 ] ... [ pN ]
>   ^           ^           ^           ^
> 
> pX is page number "X". "^" means "special" page used by boot ROM - e.g.
> every 2nd page in the range of [0, 7]. Step (2 in example is set by
> 'amlogic,boot-page-step' field. Last page in range (7 in example) is
> set by 'amlogic,boot-pages' field.
> 
> Signed-off-by: Arseniy Krasnov <avkrasnov at salutedevices.com>
> ---
>  .../bindings/mtd/amlogic,meson-nand.yaml       | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml b/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml
> index 57b6957c8415..284f0f882c32 100644
> --- a/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml
> +++ b/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml
> @@ -64,11 +64,29 @@ patternProperties:
>          items:
>            maximum: 0
>  
> +      amlogic,boot-pages:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Number of pages starting from offset 0, where a special ECC
> +          configuration must be used because it is accessed by the ROM
> +          code. This ECC configuration uses 384 bytes data blocks.
> +          Also scrambling mode is enabled for such pages.
> +
> +      amlogic,boot-page-step:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Interval between pages, accessed by the ROM code. For example
> +          we have 8 pages [0, 7]. Pages 0,2,4,6 are accessed by the
> +          ROM code, so this field will be 2 (e.g. every 2nd page). Rest
> +          of pages - 1,3,5,7 are read/written without this mode.
> +
>      unevaluatedProperties: false
>  
>      dependencies:
>        nand-ecc-strength: [nand-ecc-step-size]
>        nand-ecc-step-size: [nand-ecc-strength]
> +      amlogic,boot-pages: [nand-is-boot-medium, "amlogic,boot-page-step"]
> +      amlogic,boot-page-step: [nand-is-boot-medium, "amlogic,boot-pages"]
>  
>  
>  required: