On Mon, Jul 24, 2023 at 10:26:30AM +0200, Christian Marangi wrote:
> Add support for u-boot,env-size new property.
>
> Permit to declare a custom size of the U-Boot env that differs than the
> partition size where the U-Boot env is located.
>
> U-Boot env is validated by calculating the CRC32 on the entire env
> and in some specific case, the env size might differ from the partition
> size resulting in wrong CRC32 calculation than the expected one saved at
> the start of the partition.
Why can't you just change the partition size? There is no size really
because it is just defined in DT.
>
> This happens when U-Boot is compiled by hardcoding a specific env size
> but the env is actually placed in a bigger partition, resulting in needing
> to provide a custom value.
If u-boot is compiled that way, then shouldn't it have that size
contained within it? What happens when the DT doesn't match?
>
> Declaring this property, this value will be used for NVMEM size instead of
> the mtd partition.
>
> Add also an example to make it clear the scenario of mismatched
> partition size and actual U-Boot env.
If we do have this, then perhaps there is a generic need for a data
size property.
>
> Signed-off-by: Christian Marangi <ansuelsmth@xxxxxxxxx>
> ---
> .../devicetree/bindings/nvmem/u-boot,env.yaml | 47 +++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/nvmem/u-boot,env.yaml b/Documentation/devicetree/bindings/nvmem/u-boot,env.yaml
> index 36d97fb87865..3970725a2c57 100644
> --- a/Documentation/devicetree/bindings/nvmem/u-boot,env.yaml
> +++ b/Documentation/devicetree/bindings/nvmem/u-boot,env.yaml
> @@ -44,6 +44,24 @@ properties:
> reg:
> maxItems: 1
>
> + u-boot,env-size:
> + description: |
> + Permit to declare a custom size of the U-Boot env that differs than the
> + partition size where the U-Boot env is located.
> +
> + U-Boot env is validated by calculating the CRC32 on the entire env
> + and in some specific case, the env size might differ from the partition
> + size resulting in wrong CRC32 calculation than the expected one saved at
> + the start of the partition.
> +
> + This happens when U-Boot is compiled by hardcoding a specific env size
> + but the env is actually placed in a bigger partition, resulting in needing
> + to provide a custom value.
> +
> + Declaring this property, this value will be used for NVMEM size instead of
> + the mtd partition.
> + $ref: /schemas/types.yaml#/definitions/uint32
> +
> bootcmd:
> type: object
> description: Command to use for automatic booting
> @@ -99,3 +117,32 @@ examples:
> };
> };
> };
> + - |
> + partitions {
> + compatible = "fixed-partitions";
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + partition@0 {
> + reg = <0x0 0xc80000>;
> + label = "qcadata";
> + read-only;
> + };
> +
> + partition@c80000 {
> + label = "APPSBL";
> + reg = <0xc80000 0x500000>;
> + read-only;
> + };
> +
> + partition@1180000 {
> + compatible = "u-boot,env";
> + reg = <0x1180000 0x80000>;
> +
> + u-boot,env-size = <0x40000>;
> +
> + mac1: ethaddr {
> + #nvmem-cell-cells = <1>;
> + };
> + };
> + };
> --
> 2.40.1
>
