Re: [PATCH v4 1/2] Documentation: Documentation for qcom, llcc

[Rob Herring]

On Tue, Apr 10, 2018 at 01:08:12PM -0700, Rishabh Bhatnagar wrote:
> Documentation for last level cache controller device tree bindings,
> client bindings usage examples.

"Documentation: Documentation ..."? That wastes a lot of the subject 
line... The preferred prefix is "dt-bindings: ..."

> 
> Signed-off-by: Channagoud Kadabi <ckadabi@xxxxxxxxxxxxxx>
> Signed-off-by: Rishabh Bhatnagar <rishabhb@xxxxxxxxxxxxxx>
> ---
>  .../devicetree/bindings/arm/msm/qcom,llcc.txt      | 58 ++++++++++++++++++++++
>  1 file changed, 58 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/arm/msm/qcom,llcc.txt
> 
> diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,llcc.txt b/Documentation/devicetree/bindings/arm/msm/qcom,llcc.txt
> new file mode 100644
> index 0000000..497cf0f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/msm/qcom,llcc.txt
> @@ -0,0 +1,58 @@
> +== Introduction==
> +
> +LLCC (Last Level Cache Controller) provides last level of cache memory in SOC,
> +that can be shared by multiple clients. Clients here are different cores in the
> +SOC, the idea is to minimize the local caches at the clients and migrate to
> +common pool of memory
> +
> +Properties:
> +- compatible:
> +	 Usage: required
> +	 Value type: <string>
> +	 Definition: must be "qcom,sdm845-llcc"
> +
> +- reg:
> +	 Usage: required
> +	 Value Type: <prop-encoded-array>
> +	 Definition: must be addresses and sizes of the LLCC registers

How many address ranges?

> +
> +- #cache-cells:

This is all written as it is a common binding, but it is not one.

You already have most of the configuration data for each client in the 
driver, I think I'd just put the client connection there too. Is there 
any variation of this for a given SoC?

> +	 Usage: required
> +	 Value Type: <u32>
> +	 Definition: Number of cache cells, must be 1
> +
> +- max-slices:
> +	 usage: required
> +	 Value Type: <u32>
> +	 Definition: Number of cache slices supported by hardware

What's a slice?

> +
> +Example:
> +
> +	llcc: qcom,llcc@1100000 {
> +		compatible = "qcom,sdm845-llcc";
> +		reg = <0x1100000 0x250000>;
> +		#cache-cells = <1>;
> +		max-slices = <32>;
> +	};
> +
> +== Client ==
> +
> +Properties:
> +- cache-slice-names:
> +	 Usage: required
> +	 Value type: <stringlist>
> +	 Definition: A set of names that identify the usecase names of a
> +			client that uses cache slice. These strings are
> +			used to look up the cache slice entries by name.
> +
> +- cache-slices:
> +	 Usage: required
> +	 Value type: <prop-encoded-array>
> +	 Definition: The tuple has phandle to llcc device as the first
> +			argument and the second argument is the usecase
> +			id of the client.
> +For Example:
> +	venus {
> +		cache-slice-names = "vidsc0", "vidsc1";
> +	 	cache-slices = <&llcc VIDSC0_ID>, <&llcc VIDSC1_ID>;
> +	};
> --
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