On Tue, Mar 09, 2021 at 07:32:28PM -0700, Rob Herring wrote:

On Sun, Mar 7, 2021 at 10:31 PM Manivannan Sadhasivam
[off-list ref] wrote:

quoted

On Fri, Mar 05, 2021 at 05:36:57PM -0600, Rob Herring wrote:

quoted

On Mon, Feb 22, 2021 at 05:32:58PM +0530, Manivannan Sadhasivam wrote:

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

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

Yes, given the size of current NAND based systems around, I thought 32 bit is
enough.

Huh!? I was joking. 4GB is small nowadays. Make this 64-bit.

Well I was speaking in the context of Qcom chipsets making use of NAND. Mostly
the Qcom modem chipsets have <4GB of memory. But since this property is now not
specific to Qcom, I agree with you and will make it 64 bit.

Thanks,
Mani

Rob