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  3. [PATCH v2 0/3] MTD physmap: Adding reserved RAM support and fixing reserved_mem limitations
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[PATCH v2 2/3] dt-bindings: mtd: physmap: Allow using memory-region to access memory resources

Gregory CLEMENT posted 3 patches 1 week, 3 days ago
[PATCH v2 2/3] dt-bindings: mtd: physmap: Allow using memory-region to access memory resources
Posted by Gregory CLEMENT 1 week, 3 days ago 
Enable access to memory resources not only via I/O address using reg,
but also through a portion of main memory using memory-region. To
achieve this, new compatible strings have been introduced: mtd-mem and
mtd-memro.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 .../devicetree/bindings/mtd/mtd-physmap.yaml       | 59 +++++++++++++++-------
 1 file changed, 40 insertions(+), 19 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/mtd-physmap.yaml b/Documentation/devicetree/bindings/mtd/mtd-physmap.yaml
index 1b375dee83b0c..323e89aacaacd 100644
--- a/Documentation/devicetree/bindings/mtd/mtd-physmap.yaml
+++ b/Documentation/devicetree/bindings/mtd/mtd-physmap.yaml
@@ -13,10 +13,6 @@ description: |
   Flash chips (Memory Technology Devices) are often used for solid state
   file systems on embedded devices.
 
-allOf:
-  - $ref: mtd.yaml#
-  - $ref: /schemas/memory-controllers/mc-peripheral-props.yaml#
-
 properties:
   compatible:
     oneOf:
@@ -61,6 +57,8 @@ properties:
           - jedec-flash
           - mtd-ram
           - mtd-rom
+          - mtd-mem
+          - mtd-memro
 
   reg:
     description: |
@@ -116,6 +114,10 @@ properties:
     minItems: 1
     maxItems: 8
 
+  memory-region:
+    items:
+      - description: Memory regions to map into mtd
+
   '#address-cells':
     const: 1
 
@@ -129,21 +131,25 @@ properties:
 
 required:
   - compatible
-  - reg
-
-if:
-  properties:
-    compatible:
-      contains:
-        const: cortina,gemini-flash
-then:
-  properties:
-    syscon:
-      $ref: /schemas/types.yaml#/definitions/phandle
-      description:
-        Phandle to the syscon controller
-  required:
-    - syscon
+
+allOf:
+  - $ref: mtd.yaml#
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - mtd-mem
+              - mtd-memro
+    then:
+      required:
+        - memory-region
+      properties:
+        addr-gpios: false
+    else:
+      $ref: /schemas/memory-controllers/mc-peripheral-props.yaml#
+      required:
+        - reg
 
 unevaluatedProperties: false
 
@@ -223,4 +229,19 @@ examples:
             reg = <0 0x04000000>;
         };
     };
+
+  - |
+    /* An example using mtd-mem */
+    mem_logs: mem_logs@10000800 {
+        reg = <0x1 0x0000800 0x0 0x000f800>;
+        no-map;
+    };
+
+    memlog {
+        compatible = "mtd-mem";
+        memory-region = <&mem_log>;
+        bank-width = <4>;
+        device-width = <1>;
+    };
+
 ...

-- 
2.51.0
Re: [PATCH v2 2/3] dt-bindings: mtd: physmap: Allow using memory-region to access memory resources
Posted by Rob Herring 6 days, 21 hours ago 
On Fri, Nov 21, 2025 at 04:42:36PM +0100, Gregory CLEMENT wrote:
> Enable access to memory resources not only via I/O address using reg,
> but also through a portion of main memory using memory-region. To
> achieve this, new compatible strings have been introduced: mtd-mem and
> mtd-memro.
> 
> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
> ---
>  .../devicetree/bindings/mtd/mtd-physmap.yaml       | 59 +++++++++++++++-------
>  1 file changed, 40 insertions(+), 19 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mtd/mtd-physmap.yaml b/Documentation/devicetree/bindings/mtd/mtd-physmap.yaml
> index 1b375dee83b0c..323e89aacaacd 100644
> --- a/Documentation/devicetree/bindings/mtd/mtd-physmap.yaml
> +++ b/Documentation/devicetree/bindings/mtd/mtd-physmap.yaml
> @@ -13,10 +13,6 @@ description: |
>    Flash chips (Memory Technology Devices) are often used for solid state
>    file systems on embedded devices.
>  
> -allOf:
> -  - $ref: mtd.yaml#
> -  - $ref: /schemas/memory-controllers/mc-peripheral-props.yaml#
> -
>  properties:
>    compatible:
>      oneOf:
> @@ -61,6 +57,8 @@ properties:
>            - jedec-flash
>            - mtd-ram
>            - mtd-rom
> +          - mtd-mem
> +          - mtd-memro
>  
>    reg:
>      description: |
> @@ -116,6 +114,10 @@ properties:
>      minItems: 1
>      maxItems: 8
>  
> +  memory-region:
> +    items:
> +      - description: Memory regions to map into mtd
> +
>    '#address-cells':
>      const: 1
>  
> @@ -129,21 +131,25 @@ properties:
>  
>  required:
>    - compatible
> -  - reg
> -
> -if:
> -  properties:
> -    compatible:
> -      contains:
> -        const: cortina,gemini-flash
> -then:
> -  properties:
> -    syscon:
> -      $ref: /schemas/types.yaml#/definitions/phandle
> -      description:
> -        Phandle to the syscon controller
> -  required:
> -    - syscon
> +
> +allOf:
> +  - $ref: mtd.yaml#
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - mtd-mem
> +              - mtd-memro
> +    then:
> +      required:
> +        - memory-region
> +      properties:
> +        addr-gpios: false
> +    else:
> +      $ref: /schemas/memory-controllers/mc-peripheral-props.yaml#
> +      required:
> +        - reg
>  
>  unevaluatedProperties: false
>  
> @@ -223,4 +229,19 @@ examples:
>              reg = <0 0x04000000>;
>          };
>      };
> +
> +  - |
> +    /* An example using mtd-mem */
> +    mem_logs: mem_logs@10000800 {
> +        reg = <0x1 0x0000800 0x0 0x000f800>;
> +        no-map;
> +    };
> +
> +    memlog {
> +        compatible = "mtd-mem";
> +        memory-region = <&mem_log>;
> +        bank-width = <4>;
> +        device-width = <1>;
> +    };

To repeat v1 comment:

> If we do keep this, I'd rather just add the properties below into the
> /reserved-memory node itself. Devices are created for those nodes if
> they have 'compatible'.

To put it another way, see the ramoops binding and copy that.

Rob
Re: [PATCH v2 2/3] dt-bindings: mtd: physmap: Allow using memory-region to access memory resources
Posted by Rob Herring (Arm) 1 week, 3 days ago 
On Fri, 21 Nov 2025 16:42:36 +0100, Gregory CLEMENT wrote:
> Enable access to memory resources not only via I/O address using reg,
> but also through a portion of main memory using memory-region. To
> achieve this, new compatible strings have been introduced: mtd-mem and
> mtd-memro.
> 
> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
> ---
>  .../devicetree/bindings/mtd/mtd-physmap.yaml       | 59 +++++++++++++++-------
>  1 file changed, 40 insertions(+), 19 deletions(-)
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/mtd/mtd-physmap.example.dtb: memlog (mtd-mem): $nodename:0: 'memlog' does not match '^(flash|.*sram|nand)(@.*)?$'
	from schema $id: http://devicetree.org/schemas/mtd/mtd-physmap.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20251121-mtd-memregion-v2-2-c5535fdcebe4@bootlin.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Patchew 2.1-devel-b67e4c2

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