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

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