linux-kernel - Re: [PATCH v2 2/3] arm64: dts: qcom: sm8450: Add opp-level to indicate PCIe data rates

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Message-ID: <5f3261c3-3e44-42a5-bac7-624ce4e7041f@oss.qualcomm.com>
Date: Mon, 18 Aug 2025 14:37:03 +0530
From: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
To: Viresh Kumar <viresh.kumar@...aro.org>
Cc: Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Manivannan Sadhasivam <mani@...nel.org>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Krzysztof Wilczyński <kwilczynski@...nel.org>,
        Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
 <conor+dt@...nel.org>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v2 2/3] arm64: dts: qcom: sm8450: Add opp-level to
 indicate PCIe data rates



On 8/18/2025 2:32 PM, Viresh Kumar wrote:
> On 18-08-25, 13:52, Krishna Chaitanya Chundru wrote:
>> @@ -2210,45 +2213,67 @@ pcie1_opp_table: opp-table {
>>   				compatible = "operating-points-v2";
>>   
>>   				/* GEN 1 x1 */
>> -				opp-2500000 {
>> +				opp-2500000-1 {
> 
> Why mention -1 here when there is only one entry with this freq value
> ?
> 
>>   					opp-hz = /bits/ 64 <2500000>;
>>   					required-opps = <&rpmhpd_opp_low_svs>;
>>   					opp-peak-kBps = <250000 1>;
>> +					opp-level = <1>;
>>   				};
>>   
>> -				/* GEN 1 x2 and GEN 2 x1 */
>> -				opp-5000000 {
>> +				/* GEN 1 x2 */
>> +				opp-5000000-1 {
>> +					opp-hz = /bits/ 64 <5000000>;
>> +					required-opps = <&rpmhpd_opp_low_svs>;
>> +					opp-peak-kBps = <500000 1>;
>> +					opp-level = <1>;
>> +				};
>> +
>> +				/* GEN 2 x1 */
>> +				opp-5000000-2 {
>>   					opp-hz = /bits/ 64 <5000000>;
>>   					required-opps = <&rpmhpd_opp_low_svs>;
>>   					opp-peak-kBps = <500000 1>;
>> +					opp-level = <2>;
>>   				};
> 
> This looks okay.
> 
>>   
>>   				/* GEN 2 x2 */
>> -				opp-10000000 {
>> +				opp-10000000-2 {
> 
> Why -2 here ?
> 
>>   					opp-hz = /bits/ 64 <10000000>;
>>   					required-opps = <&rpmhpd_opp_low_svs>;
>>   					opp-peak-kBps = <1000000 1>;
>> +					opp-level = <2>;
>>   				};
>>   
>>   				/* GEN 3 x1 */
>> -				opp-8000000 {
>> +				opp-8000000-3 {
> 
> same.
> 
>>   					opp-hz = /bits/ 64 <8000000>;
>>   					required-opps = <&rpmhpd_opp_nom>;
>>   					opp-peak-kBps = <984500 1>;
>> +					opp-level = <3>;
>> +				};
>> +
>> +				/* GEN 3 x2 */
>> +				opp-16000000-3 {
> 
> Shouldn't this be opp-16000000-1 only ? This is the first occurrence
> 16000000.
> 
>> +					opp-hz = /bits/ 64 <16000000>;
>> +					required-opps = <&rpmhpd_opp_nom>;
>> +					opp-peak-kBps = <1969000 1>;
>> +					opp-level = <3>;
>>   				};
>>   
>> -				/* GEN 3 x2 and GEN 4 x1 */
>> -				opp-16000000 {
>> +				/* GEN 4 x1 */
>> +				opp-16000000-4 {
> 
> opp-16000000-2 ?
I tried to add the level as prefix as that will indicate the PCIe date
rate also instead of 1, 2 to make more aligned with the PCIe 
representations. I will update this in the commit text in my next
series.

- Krishna Chaitanya.
>