[PATCH 1/2] dt-bindings: nvmem: add "data-size" property

[PATCH 1/2] dt-bindings: nvmem: add "data-size" property

[Rafał Miłecki]

From: Rafał Miłecki <rafal@milecki.pl>

Allow specifying NVMEM device content size in case it differs from
device total size.

Cc: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
 Documentation/devicetree/bindings/nvmem/nvmem.yaml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/nvmem/nvmem.yaml b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
index 4fd015d402ce..095aed4250de 100644
--- a/Documentation/devicetree/bindings/nvmem/nvmem.yaml
+++ b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
@@ -26,6 +26,13 @@ properties:
   "#size-cells":
     const: 1
 
+  data-size:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      NVMEM device actual data (content) size. It may be need to be specified
+      if it differs by design from the total NVMEM device size and it's
+      impossible to determine it on runtime.
+
   read-only:
     $ref: /schemas/types.yaml#/definitions/flag
     description:
-- 
2.35.3


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[PATCH 2/2] dt-bindings: nvmem: u-boot,env: describe "data-size" property

[Rafał Miłecki]

From: Rafał Miłecki <rafal@milecki.pl>

Describe what "data-size" means in U-Boot env context and why it may be
needed. It's a generic property but giving it some extra meaning in
U-Boot context may be helpful.

Cc: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
 .../devicetree/bindings/nvmem/u-boot,env.yaml          | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/devicetree/bindings/nvmem/u-boot,env.yaml b/Documentation/devicetree/bindings/nvmem/u-boot,env.yaml
index 9c36afc7084b..0006f022d0af 100644
--- a/Documentation/devicetree/bindings/nvmem/u-boot,env.yaml
+++ b/Documentation/devicetree/bindings/nvmem/u-boot,env.yaml
@@ -44,6 +44,15 @@ properties:
   reg:
     maxItems: 1
 
+  data-size:
+    description:
+      U-Boot environment data size is set and hardcoded during compilation using
+      CONFIG_ENV_SIZE. Knowing it is critical for CRC32 checksum calculation.
+
+      This property allows specifying it in case it differs from NVMEM device
+      size. It may happen if device partitioning was designed with different
+      concepts in mind (like block alignment or future-proof size).
+
   bootcmd:
     type: object
     description: Command to use for automatic booting
@@ -76,6 +85,7 @@ examples:
         env: partition@40000 {
             compatible = "u-boot,env";
             reg = <0x40000 0x10000>;
+            data-size = <0x4000>;
 
             mac: ethaddr {
                 #nvmem-cell-cells = <1>;
-- 
2.35.3


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Re: [PATCH 1/2] dt-bindings: nvmem: add "data-size" property

[Rafał Miłecki]

On 13.12.2023 16:47, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@milecki.pl>
> 
> Allow specifying NVMEM device content size in case it differs from
> device total size.
> 
> Cc: Christian Marangi <ansuelsmth@gmail.com>
> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

I forgot to link Rob's comment where he suggested we may need such a property:
https://patchwork.ozlabs.org/comment/3154781/

Let's now see if I got it right.


> ---
>   Documentation/devicetree/bindings/nvmem/nvmem.yaml | 7 +++++++
>   1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/nvmem/nvmem.yaml b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
> index 4fd015d402ce..095aed4250de 100644
> --- a/Documentation/devicetree/bindings/nvmem/nvmem.yaml
> +++ b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
> @@ -26,6 +26,13 @@ properties:
>     "#size-cells":
>       const: 1
>   
> +  data-size:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      NVMEM device actual data (content) size. It may be need to be specified
> +      if it differs by design from the total NVMEM device size and it's
> +      impossible to determine it on runtime.
> +
>     read-only:
>       $ref: /schemas/types.yaml#/definitions/flag
>       description:


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Re: [PATCH 1/2] dt-bindings: nvmem: add "data-size" property

[Rob Herring]

On Wed, Dec 13, 2023 at 04:47:20PM +0100, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@milecki.pl>
> 
> Allow specifying NVMEM device content size in case it differs from
> device total size.
> 
> Cc: Christian Marangi <ansuelsmth@gmail.com>
> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
> ---
>  Documentation/devicetree/bindings/nvmem/nvmem.yaml | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/nvmem/nvmem.yaml b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
> index 4fd015d402ce..095aed4250de 100644
> --- a/Documentation/devicetree/bindings/nvmem/nvmem.yaml
> +++ b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
> @@ -26,6 +26,13 @@ properties:
>    "#size-cells":
>      const: 1
>  
> +  data-size:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      NVMEM device actual data (content) size. It may be need to be specified
> +      if it differs by design from the total NVMEM device size and it's
> +      impossible to determine it on runtime.

'data-size' is already defined in 
Documentation/devicetree/bindings/eeprom/microchip,93lc46b.yaml.

That would be fine, but it's defining bits per word. So I think it's 
better if we call this something else. 'total-data-size' or 
'actual-data-size'?

I think Simon had something similar for binman.

Rob

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