linux-kernel - Re: [PATCH 0/3] opp: Add bw_factor support to adjust bandwidth dynamically

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250811101729.vwrtqg33lusk7h6p@vireshk-i7>
Date: Mon, 11 Aug 2025 15:47:29 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
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 0/3] opp: Add bw_factor support to adjust bandwidth
 dynamically

On 11-08-25, 15:35, Krishna Chaitanya Chundru wrote:
> Thanks Viresh for the suggestion. We will try this.
> Can you confirm this is what you are expecting.
> 
> dt change
> --- a/arch/arm64/boot/dts/qcom/sm8450.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sm8450.dtsi
> @@ -2214,13 +2214,23 @@ opp-2500000 {
>                                         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 */
> +                               /* GEN 1 x2 */
>                                 opp-5000000 {
>                                         opp-hz = /bits/ 64 <5000000>;
>                                         required-opps =
> <&rpmhpd_opp_low_svs>;
>                                         opp-peak-kBps = <500000 1>;
> +                                       opp-level = <1>;
> +                               };
> +
> +                               /* GEN 2 x1 */
> +                               opp-5000000 {

The node-name has to be different, but freq can be same. Something
like opp-5000000-N, where N = 1, 2, 3.

> +                                       opp-hz = /bits/ 64 <5000000>;
> +                                       required-opps =
> <&rpmhpd_opp_low_svs>;
> +                                       opp-peak-kBps = <500000 1>;
> +                                       opp-level = <2>;
>                                 };

> And in the driver I need to have a change in OPP framework which
> returns OPP based on both frequency and level something like
> dev_pm_opp_find_level_freq_exact(struct device *dev,
> unsigned int level, unsigned int freq);

I thought you wanted OPP based on freq and bandwidth ? But yeah, a new
OPP API like: dev_pm_opp_find_key_exact(dev, *key);

where,

struct dev_pm_opp_key {
        unsigned long *freq;
        unsigned int *level;
        unsigned int *bw;
}

and match all non-NULL values only to begin with.

-- 
viresh