Re: [PATCH v6 08/52] dt-bindings: memory: tegra20: emc: Document mfd-simple compatible and statistics sub-device

Rob Herring
2020-10-29T01:04:38Z

On Mon, Oct 26, 2020 at 01:16:51AM +0300, Dmitry Osipenko wrote:
> External Memory Controller can gather various hardware statistics that
> are intended to be used for debugging purposes and for dynamic frequency
> scaling of memory bus.
>
> Document the new mfd-simple compatible and EMC statistics sub-device.

It's simple-mfd.

That should only be used if the child has no dependencies on the parent
node (and driver).

> The subdev contains EMC DFS OPP table and interconnect paths to be used
> for dynamic scaling of system's memory bandwidth based on EMC utilization
> statistics.
>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> .../memory-controllers/nvidia,tegra20-emc.txt | 43 +++++++++++++++++--
> 1 file changed, 40 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> index 8d09b228ac42..382aabcd6952 100644
> --- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> @@ -4,7 +4,7 @@ Properties:
> - name : Should be emc
> - #address-cells : Should be 1
> - #size-cells : Should be 0
> -- compatible : Should contain "nvidia,tegra20-emc".
> +- compatible : Should contain "nvidia,tegra20-emc" and "simple-mfd".
> - reg : Offset and length of the register set for the device
> - nvidia,use-ram-code : If present, the sub-nodes will be addressed
> and chosen using the ramcode board selector. If omitted, only one
> @@ -17,7 +17,8 @@ Properties:
> - core-supply: Phandle of voltage regulator of the SoC "core" power domain.
> - operating-points-v2: See ../bindings/opp/opp.txt for details.
>
> -Child device nodes describe the memory settings for different configurations and clock rates.
> +Child device nodes describe the memory settings for different configurations and clock rates,
> +as well as EMC activity statistics collection sub-device.
>
> Example:
>
> @@ -31,17 +32,34 @@ Example:
> ...
> };
>
> + emc_bw_dfs_opp_table: emc_opp_table1 {
> + compatible = "operating-points-v2";
> +
> + opp@36000000 {
> + opp-hz = /bits/ 64 <36000000>;
> + opp-peak-kBps = <144000>;
> + };
> + ...
> + };
> +
> memory-controller@7000f400 {
> #address-cells = < 1 >;
> #size-cells = < 0 >;
> #interconnect-cells = < 0 >;
> - compatible = "nvidia,tegra20-emc";
> + compatible = "nvidia,tegra20-emc", "simple-mfd";
> reg = <0x7000f400 0x400>;
> interrupts = <0 78 0x04>;
> clocks = <&tegra_car TEGRA20_CLK_EMC>;
> nvidia,memory-controller = <&mc>;
> core-supply = <&core_vdd_reg>;
> operating-points-v2 = <&emc_icc_dvfs_opp_table>;
> +
> + emc-stats {
> + compatible = "nvidia,tegra20-emc-statistics";
> + operating-points-v2 = <&emc_bw_dfs_opp_table>;
> + interconnects = <&mc TEGRA20_MC_MPCORER &emc>;
> + interconnect-names = "cpu";
> + };
> }
>
>
> @@ -120,3 +138,22 @@ Properties:
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> 0 0 0 0 >;
> };
> +
> +
> +
> +Embedded Memory Controller statistics gathering sub-device
> +
> +EMC statistics subdev gathers information about hardware utilization
> +which is intended to be used for debugging purposes and for dynamic
> +frequency scaling based on the collected stats.
> +
> +Properties:
> +- name : Should be emc-stats.
> +- compatible : Should contain "nvidia,tegra20-emc-statistics".
> +- operating-points-v2: See ../bindings/opp/opp.txt for details.
> +- interconnects: Should contain entries for memory clients sitting on
> + MC->EMC memory interconnect path.
> +- interconnect-names: Should include name of the interconnect path for each
> + interconnect entry. Consult TRM documentation for
> + information about available memory clients, see MEMORY
> + CONTROLLER section.
> --
> 2.27.0
>