Hi Manivannan,

Manivannan Sadhasivam [off-list ref] wrote on Tue,
23 Feb 2021 23:15:46 +0530:

Hi Miquel,

On Tue, Feb 23, 2021 at 05:49:22PM +0100, Miquel Raynal wrote:

quoted

Hi Manivannan,

Manivannan Sadhasivam [off-list ref] wrote on Mon,
22 Feb 2021 17:32:58 +0530:
  

quoted

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 <redacted>
---
 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
+        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).  

What does this "(optional)" means? If you mean the property is optional
then it should be described accordingly in the yaml file, or am I
missing something?
  

IIUC, if a property is not listed under "required" section then it is
optional. But I've added the quote here to just make it explicit.

Absolutely, I was just wondering why you mentioned it here. I don't
think it's useful, you can drop it.

quoted

I wonder if it wouldn't be better to make this a NAND chip node
property. I don't think a qcom prefix is needed as potentially many
other SoCs might have the same "feature".

I'm fine adding support for it in the qcom driver only though.
  

Hmm, sounds good to me.

Thanks,
Mani

quoted

quoted

+
 allOf:
   - $ref: "nand-controller.yaml#"
   

Thanks,
Miquèl  

Thanks,
Miquèl