Re: [PATCH v5 2/4] devicetree: bindings: Document Krait CPU/L1 EDAC

[Lorenzo Pieralisi]

On Thu, Jan 16, 2014 at 01:38:40AM +0000, Stephen Boyd wrote:
> On 01/15, Stephen Boyd wrote:
> > 
> > Ah sorry, I forgot to put the compatible property here like in
> > the dts change. I'll do that in the next revision. Yes we need a
> > compatible property here to match the platform driver.
> > 
> 
> This is the replacement patch
> 
> -----8<------
> From: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
> Subject: [PATCH v9] devicetree: bindings: Document Krait CPU/L1 EDAC
> 
> The Krait CPU/L1 error reporting device is made up a per-CPU
> interrupt. While we're here, document the next-level-cache
> property that's used by the Krait EDAC driver.
> 
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Kumar Gala <galak@xxxxxxxxxxxxxx>
> Cc: <devicetree@xxxxxxxxxxxxxxx>
> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
> ---
>  Documentation/devicetree/bindings/arm/cpus.txt | 58 ++++++++++++++++++++++++++
>  1 file changed, 58 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt
> index 91304353eea4..03a529e791c4 100644
> --- a/Documentation/devicetree/bindings/arm/cpus.txt
> +++ b/Documentation/devicetree/bindings/arm/cpus.txt
> @@ -62,6 +62,20 @@ nodes to be present and contain the properties described below.
>  		Value type: <u32>
>  		Definition: must be set to 0
>  
> +	- compatible
> +		Usage: optional
> +		Value type: <string>
> +		Definition: should be one of the compatible strings listed
> +			    in the cpu node compatible property. This property
> +			    shall only be present if all the cpu nodes have the
> +			    same compatible property.

Do we really want to do that ? I am not sure. A cpus node is supposed to
be a container node, we should not define this binding just because we
know the kernel creates a platform device for it then.

interrupts is a cpu node property and I think it should be kept as such.

I know it will be duplicated and I know you can't rely on a platform
device for probing (since if I am not mistaken, removing a compatible
string from cpus prevents its platform device creation), but that's an issue
related to how the kernel works, you should not define DT bindings to solve
that IMHO.

Lorenzo

> +
> +	- interrupts
> +		Usage: required when node contains cpus with compatible
> +		       string "qcom,krait".
> +		Value type: <prop-encoded-array>
> +		Definition: L1/CPU error interrupt
> +
>  - cpu node
>  
>  	Description: Describes a CPU in an ARM based system
> @@ -191,6 +205,11 @@ nodes to be present and contain the properties described below.
>  			  property identifying a 64-bit zero-initialised
>  			  memory location.
>  
> +	- next-level-cache
> +		Usage: optional
> +		Value type: <phandle>
> +		Definition: phandle pointing to the next level cache
> +
>  Example 1 (dual-cluster big.LITTLE system 32-bit):
>  
>  	cpus {
> @@ -382,3 +401,42 @@ cpus {
>  		cpu-release-addr = <0 0x20000000>;
>  	};
>  };
> +
> +
> +Example 5 (Krait 32-bit system):
> +
> +cpus {
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +	interrupts = <1 9 0xf04>;
> +	compatible = "qcom,krait";
> +
> +	cpu@0 {
> +		device_type = "cpu";
> +		reg = <0>;
> +		next-level-cache = <&L2>;
> +	};
> +
> +	cpu@1 {
> +		device_type = "cpu";
> +		reg = <1>;
> +		next-level-cache = <&L2>;
> +	};
> +
> +	cpu@2 {
> +		device_type = "cpu";
> +		reg = <2>;
> +		next-level-cache = <&L2>;
> +	};
> +
> +	cpu@3 {
> +		device_type = "cpu";
> +		reg = <3>;
> +		next-level-cache = <&L2>;
> +	};
> +
> +	L2: l2-cache {
> +		compatible = "cache";
> +		interrupts = <0 2 0x4>;
> +	};
> +};
> -- 
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> hosted by The Linux Foundation
> 

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