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

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Message-ID: <479a021a-36eb-7b44-9e14-51e16d1b64fb@linaro.org>
Date:   Wed, 29 Jun 2022 13:32:02 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Rajendra Nayak <quic_rjendra@...cinc.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Georgi Djakov <djakov@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, linux-arm-msm@...r.kernel.org,
        linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:     Thara Gopinath <thara.gopinath@...il.com>
Subject: Re: [PATCH v5 4/4] arm64: dts: qcom: sdm845: Add CPU BWMON

On 29/06/2022 13:22, Rajendra Nayak wrote:
> 
> 
> 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@...il.com>
>> Signed-off-by: Thara Gopinath <thara.gopinath@...il.com>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>> ---
>>   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@...0000 {
>>   			interrupts = <GIC_SPI 582 IRQ_TYPE_LEVEL_HIGH>;
>>   		};
>>   
>> +		pmu@...6400 {
>> +			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?

Yes, a bit.

Best regards,
Krzysztof