Re: [PATCH v5 4/4] arm64: dts: qcom: sdm845: Add CPU BWMON

From: Rajendra Nayak
Date: Wed Jun 29 2022 - 07:23:06 EST




On 6/29/2022 1:22 PM, Krzysztof Kozlowski wrote:
Add device node for CPU-memory BWMON device (bandwidth monitoring) on
SDM845 measuring bandwidth between CPU (gladiator_noc) and Last Level
Cache (memnoc). Usage of this BWMON allows to remove fixed bandwidth
votes from cpufreq (CPU nodes) thus achieve high memory throughput even
with lower CPU frequencies.

Co-developed-by: Thara Gopinath <thara.gopinath@xxxxxxxxx>
Signed-off-by: Thara Gopinath <thara.gopinath@xxxxxxxxx>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
---
arch/arm64/boot/dts/qcom/sdm845.dtsi | 38 ++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
index 83e8b63f0910..e0f088996390 100644
--- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
@@ -2026,6 +2026,44 @@ llcc: system-cache-controller@1100000 {
interrupts = <GIC_SPI 582 IRQ_TYPE_LEVEL_HIGH>;
};
+ pmu@1436400 {
+ compatible = "qcom,sdm845-cpu-bwmon", "qcom,msm8998-cpu-bwmon";
+ reg = <0 0x01436400 0 0x600>;
+ interrupts = <GIC_SPI 581 IRQ_TYPE_LEVEL_HIGH>;
+ interconnects = <&gladiator_noc MASTER_APPSS_PROC 3 &mem_noc SLAVE_LLCC 3>;
+
+ operating-points-v2 = <&cpu_bwmon_opp_table>;
+
+ cpu_bwmon_opp_table: opp-table {
+ compatible = "operating-points-v2";
+
+ /*
+ * The interconnect paths bandwidths taken from
+ * cpu4_opp_table bandwidth.
+ * They also match different tables from
+ * msm-4.9 downstream kernel:
+ * - the OSM L3 from bandwidth table of
+ * qcom,cpu4-l3lat-mon (qcom,core-dev-table);
+ * bus width: 16 bytes;
+ */

Maybe the comment needs an update?

+ opp-0 {
+ opp-peak-kBps = <4800000>;
+ };
+ opp-1 {
+ opp-peak-kBps = <9216000>;
+ };
+ opp-2 {
+ opp-peak-kBps = <15052800>;
+ };
+ opp-3 {
+ opp-peak-kBps = <20889600>;
+ };
+ opp-4 {
+ opp-peak-kBps = <25497600>;
+ };
+ };
+ };
+
pcie0: pci@1c00000 {
compatible = "qcom,pcie-sdm845";
reg = <0 0x01c00000 0 0x2000>,