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SubjectRe: [PATCH v4 1/2] Documentation: Documentation for qcom, llcc
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@codeaurora.org>
> Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
> ---
> .../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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> a Linux Foundation Collaborative Project
>
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