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

Dmitry Osipenko
2020-10-25T22:18:13Z

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.
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