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

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Date:   Mon, 26 Oct 2020 01:16:51 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Georgi Djakov <georgi.djakov@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Mikko Perttunen <cyndis@...si.fi>,
        Viresh Kumar <vireshk@...nel.org>,
        Peter Geis <pgwipeout@...il.com>,
        Nicolas Chauvet <kwizart@...il.com>,
        Krzysztof Kozlowski <krzk@...nel.org>
Cc:     linux-tegra@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        devicetree@...r.kernel.org
Subject: [PATCH v6 08/52] dt-bindings: memory: tegra20: emc: Document mfd-simple compatible and statistics sub-device

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@...il.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@...00000 {
+			opp-hz = /bits/ 64 <36000000>;
+			opp-peak-kBps = <144000>;
+		};
+		...
+	};
+
 	memory-controller@...0f400 {
 		#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