Re: [PATCH 2/3] dt-bindings: mtd: Add a property to declare secure regions in Qcom NANDc

[Rob Herring]

On Mon, Feb 22, 2021 at 05:32:58PM +0530, Manivannan Sadhasivam wrote:
> On a typical end product, a vendor may choose to secure some regions in
> the NAND memory which are supposed to stay intact between FW upgrades.
> The access to those regions will be blocked by a secure element like
> Trustzone. So the normal world software like Linux kernel should not
> touch these regions (including reading).
> 
> So let's add a property for declaring such secure regions so that the
> driver can skip touching them.
> 
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> ---
>  Documentation/devicetree/bindings/mtd/qcom,nandc.yaml | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mtd/qcom,nandc.yaml b/Documentation/devicetree/bindings/mtd/qcom,nandc.yaml
> index 84ad7ff30121..7500e20da9c1 100644
> --- a/Documentation/devicetree/bindings/mtd/qcom,nandc.yaml
> +++ b/Documentation/devicetree/bindings/mtd/qcom,nandc.yaml
> @@ -48,6 +48,13 @@ patternProperties:
>          enum:
>            - 512
>  
> +      qcom,secure-regions:
> +        $ref: /schemas/types.yaml#/definitions/uint32-array

Don't you need 64-bit regions potentially? Though 4GB should be enough 
for anyone.

If more than one addr+size, then you need a matrix.

> +        description:
> +          Regions in the NAND memory which are protected using a secure element
> +          like Trustzone. This property contains the start address and size of
> +          the secure regions present (optional).
> +
>  allOf:
>    - $ref: "nand-controller.yaml#"
>  
> -- 
> 2.25.1
>