linux-kernel - Re: [PATCH v12 2/4] dt-bindings: remoteproc: add Tightly Coupled Memory (TCM) bindings

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Message-ID: <fb78bdda-2ec7-4fcc-888e-233905a9386c@linaro.org>
Date: Sat, 9 Mar 2024 14:25:25 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Tanmay Shah <tanmay.shah@....com>, andersson@...nel.org,
 mathieu.poirier@...aro.org, robh+dt@...nel.org,
 krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
 michal.simek@....com, ben.levinsky@....com
Cc: linux-remoteproc@...r.kernel.org, devicetree@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 Radhey Shyam Pandey <radhey.shyam.pandey@....com>
Subject: Re: [PATCH v12 2/4] dt-bindings: remoteproc: add Tightly Coupled
 Memory (TCM) bindings

On 01/03/2024 19:16, Tanmay Shah wrote:
> From: Radhey Shyam Pandey <radhey.shyam.pandey@....com>
> 
> Introduce bindings for TCM memory address space on AMD-xilinx Zynq
> UltraScale+ platform. It will help in defining TCM in device-tree
> and make it's access platform agnostic and data-driven.
> 
> Tightly-coupled memories(TCMs) are low-latency memory that provides
> predictable instruction execution and predictable data load/store
> timing. Each Cortex-R5F processor contains two 64-bit wide 64 KB memory
> banks on the ATCM and BTCM ports, for a total of 128 KB of memory.
> 
> The TCM resources(reg, reg-names and power-domain) are documented for
> each TCM in the R5 node. The reg and reg-names are made as required
> properties as we don't want to hardcode TCM addresses for future
> platforms and for zu+ legacy implementation will ensure that the
> old dts w/o reg/reg-names works and stable ABI is maintained.
> 
> It also extends the examples for TCM split and lockstep modes.
> 
> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@....com>
> Signed-off-by: Tanmay Shah <tanmay.shah@....com>
> ---
> 
> Changes in v12:
>   - add "reg", "reg-names" and "power-domains" in pattern properties
>   - add "reg" and "reg-names" in required list
>   - keep "power-domains" in required list as it was before the change
> 
> Changes in v11:
>   - Fix yamllint warning and reduce indentation as needed
> 
>  .../remoteproc/xlnx,zynqmp-r5fss.yaml         | 188 ++++++++++++++++--
>  1 file changed, 168 insertions(+), 20 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/remoteproc/xlnx,zynqmp-r5fss.yaml b/Documentation/devicetree/bindings/remoteproc/xlnx,zynqmp-r5fss.yaml
> index 78aac69f1060..dc6ce308688f 100644
> --- a/Documentation/devicetree/bindings/remoteproc/xlnx,zynqmp-r5fss.yaml
> +++ b/Documentation/devicetree/bindings/remoteproc/xlnx,zynqmp-r5fss.yaml
> @@ -20,9 +20,21 @@ properties:
>    compatible:
>      const: xlnx,zynqmp-r5fss
>  
> +  "#address-cells":
> +    const: 2
> +
> +  "#size-cells":
> +    const: 2
> +
> +  ranges:
> +    description: |
> +      Standard ranges definition providing address translations for
> +      local R5F TCM address spaces to bus addresses.
> +
>    xlnx,cluster-mode:
>      $ref: /schemas/types.yaml#/definitions/uint32
>      enum: [0, 1, 2]
> +    default: 1
>      description: |
>        The RPU MPCore can operate in split mode (Dual-processor performance), Safety
>        lock-step mode(Both RPU cores execute the same code in lock-step,
> @@ -37,7 +49,7 @@ properties:
>        2: single cpu mode
>  
>  patternProperties:
> -  "^r5f-[a-f0-9]+$":
> +  "^r5f@[0-9a-f]+$":
>      type: object
>      description: |
>        The RPU is located in the Low Power Domain of the Processor Subsystem.
> @@ -54,8 +66,17 @@ patternProperties:
>        compatible:
>          const: xlnx,zynqmp-r5f
>  
> +      reg:
> +        minItems: 1
> +        maxItems: 4
> +
> +      reg-names:
> +        minItems: 1
> +        maxItems: 4
> +
>        power-domains:
> -        maxItems: 1
> +        minItems: 2
> +        maxItems: 5
>  
>        mboxes:
>          minItems: 1
> @@ -101,35 +122,162 @@ patternProperties:
>  
>      required:
>        - compatible
> +      - reg
> +      - reg-names
>        - power-domains
>  
> -    unevaluatedProperties: false
> -
>  required:
>    - compatible
> +  - "#address-cells"
> +  - "#size-cells"
> +  - ranges
> +
> +allOf:
> +  - if:
> +      properties:
> +        xlnx,cluster-mode:
> +          enum:
> +            - 1
> +    then:
> +      patternProperties:
> +        "^r5f@[0-9a-f]+$":
> +          type: object
> +
> +          properties:
> +            reg:
> +              minItems: 1
> +              items:
> +                - description: ATCM internal memory
> +                - description: BTCM internal memory
> +                - description: extra ATCM memory in lockstep mode
> +                - description: extra BTCM memory in lockstep mode
> +
> +            reg-names:
> +              minItems: 1
> +              items:
> +                - const: atcm0
> +                - const: btcm0
> +                - const: atcm1
> +                - const: btcm1

Why power domains are flexible?

> +
> +    else:
> +      patternProperties:
> +        "^r5f@[0-9a-f]+$":
> +          type: object
> +
> +          properties:
> +            reg:
> +              minItems: 1
> +              items:
> +                - description: ATCM internal memory
> +                - description: BTCM internal memory
> +
> +            reg-names:
> +              minItems: 1
> +              items:
> +                - const: atcm0
> +                - const: btcm0
> +
> +            power-domains:
> +              maxItems: 3

Please list power domains.

>  
>  additionalProperties: false


Best regards,
Krzysztof