Re: [PATCH 02/12] dt-bindings: arm: msm: Fix register regions used for LLCC banks

From: Bjorn Andersson <andersson@kernel.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
	bp@alien8.de, tony.luck@intel.com, quic_saipraka@quicinc.com,
	konrad.dybcio@linaro.org, linux-arm-msm@vger.kernel.org,
	linux-kernel@vger.kernel.org, james.morse@arm.com,
	mchehab@kernel.org, rric@kernel.org, linux-edac@vger.kernel.org,
	quic_ppareek@quicinc.com, stable@vger.kernel.org
Subject: Re: [PATCH 02/12] dt-bindings: arm: msm: Fix register regions used for LLCC banks
Date: Wed, 7 Dec 2022 10:08:25 -0600	[thread overview]
Message-ID: <20221207160825.nafywxehxjx42kww@builder.lan> (raw)
In-Reply-To: <20221207135922.314827-3-manivannan.sadhasivam@linaro.org>

On Wed, Dec 07, 2022 at 07:29:11PM +0530, Manivannan Sadhasivam wrote:
> Register regions of the LLCC banks are located at separate addresses.
> Currently, the binding just lists the LLCC0 base address and specifies
> the size to cover all banks. This is not the correct approach since,
> there are holes and other registers located in between.
> 
> So let's specify the base address of each LLCC bank. It should be noted
> that the bank count differs for each SoC, so that also needs to be taken
> into account in the binding.
> 
> Cc: <stable@vger.kernel.org> # 4.19
> Fixes: 7e5700ae64f6 ("dt-bindings: Documentation for qcom, llcc")
> Reported-by: Parikshit Pareek <quic_ppareek@quicinc.com>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>  .../bindings/arm/msm/qcom,llcc.yaml           | 125 ++++++++++++++++--
>  1 file changed, 114 insertions(+), 11 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,llcc.yaml b/Documentation/devicetree/bindings/arm/msm/qcom,llcc.yaml
> index d1df49ffcc1b..7f694baa017c 100644
> --- a/Documentation/devicetree/bindings/arm/msm/qcom,llcc.yaml
> +++ b/Documentation/devicetree/bindings/arm/msm/qcom,llcc.yaml
> @@ -33,14 +33,12 @@ properties:
>        - qcom,sm8550-llcc
>  
>    reg:
> -    items:
> -      - description: LLCC base register region
> -      - description: LLCC broadcast base register region
> +    minItems: 2
> +    maxItems: 9
>  
>    reg-names:
> -    items:
> -      - const: llcc_base
> -      - const: llcc_broadcast_base
> +    minItems: 2
> +    maxItems: 9

Afaict changing llcc_base to llcc0_base would not allow the
implementation to find the llcc_base region with an older DTB.

But if you instead modify the driver to pick up N-1 regions for base and
the last for broadcast, by index. This should continue to work for the
platforms where it actually worked.

Based on that I suggest that you just remove reg-names from the binding.
It will clean up the binding and we won't have reg-names containing
"llcc" or "base" :)

Regards,
Bjorn

>  
>    interrupts:
>      maxItems: 1
> @@ -50,15 +48,120 @@ required:
>    - reg
>    - reg-names
>  
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - qcom,sc7180-llcc
> +              - qcom,sm6350-llcc
> +    then:
> +      properties:
> +        reg:
> +          items:
> +            - description: LLCC0 base register region
> +            - description: LLCC broadcast base register region
> +        reg-names:
> +          items:
> +            - const: llcc0_base
> +            - const: llcc_broadcast_base
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - qcom,sc7280-llcc
> +    then:
> +      properties:
> +        reg:
> +          items:
> +            - description: LLCC0 base register region
> +            - description: LLCC1 base register region
> +            - description: LLCC broadcast base register region
> +        reg-names:
> +          items:
> +            - const: llcc0_base
> +            - const: llcc1_base
> +            - const: llcc_broadcast_base
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - qcom,sc8180x-llcc
> +              - qcom,sc8280xp-llcc
> +    then:
> +      properties:
> +        reg:
> +          items:
> +            - description: LLCC0 base register region
> +            - description: LLCC1 base register region
> +            - description: LLCC2 base register region
> +            - description: LLCC3 base register region
> +            - description: LLCC4 base register region
> +            - description: LLCC5 base register region
> +            - description: LLCC6 base register region
> +            - description: LLCC7 base register region
> +            - description: LLCC broadcast base register region
> +        reg-names:
> +          items:
> +            - const: llcc0_base
> +            - const: llcc1_base
> +            - const: llcc2_base
> +            - const: llcc3_base
> +            - const: llcc4_base
> +            - const: llcc5_base
> +            - const: llcc6_base
> +            - const: llcc7_base
> +            - const: llcc_broadcast_base
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - qcom,sdm845-llcc
> +              - qcom,sm8150-llcc
> +              - qcom,sm8250-llcc
> +              - qcom,sm8350-llcc
> +              - qcom,sm8450-llcc
> +    then:
> +      properties:
> +        reg:
> +          items:
> +            - description: LLCC0 base register region
> +            - description: LLCC1 base register region
> +            - description: LLCC2 base register region
> +            - description: LLCC3 base register region
> +            - description: LLCC broadcast base register region
> +        reg-names:
> +          items:
> +            - const: llcc0_base
> +            - const: llcc1_base
> +            - const: llcc2_base
> +            - const: llcc3_base
> +            - const: llcc_broadcast_base
> +
>  additionalProperties: false
>  
>  examples:
>    - |
>      #include <dt-bindings/interrupt-controller/arm-gic.h>
>  
> -    system-cache-controller@1100000 {
> -      compatible = "qcom,sdm845-llcc";
> -      reg = <0x1100000 0x200000>, <0x1300000 0x50000> ;
> -      reg-names = "llcc_base", "llcc_broadcast_base";
> -      interrupts = <GIC_SPI 582 IRQ_TYPE_LEVEL_HIGH>;
> +    soc {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +
> +        system-cache-controller@1100000 {
> +          compatible = "qcom,sdm845-llcc";
> +          reg = <0 0x01100000 0 0x50000>, <0 0x01180000 0 0x50000>,
> +                <0 0x01200000 0 0x50000>, <0 0x01280000 0 0x50000>,
> +                <0 0x01300000 0 0x50000>;
> +          reg-names = "llcc0_base", "llcc1_base", "llcc2_base",
> +                "llcc3_base", "llcc_broadcast_base";
> +          interrupts = <GIC_SPI 582 IRQ_TYPE_LEVEL_HIGH>;
> +        };
>      };
> -- 
> 2.25.1
> 