linux-kernel - Re: [PATCH v2 1/3] PM/OPP: Support to match OPP based on both frequency and level.

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Message-ID: <20250818085517.dj2nk4jeex263hvj@vireshk-i7>
Date: Mon, 18 Aug 2025 14:25:17 +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 v2 1/3] PM/OPP: Support to match OPP based on both
 frequency and level.

On 18-08-25, 13:52, Krishna Chaitanya Chundru wrote:
> +static bool _compare_opp_key_exact(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
> +				   struct dev_pm_opp_key opp_key, struct dev_pm_opp_key key)
> +{
> +	bool freq_match = (opp_key.freq == 0 || key.freq == 0 || opp_key.freq == key.freq);

Why !opp_key.freq is okay ? If the user has provided a freq value,
then it must match. Isn't it ?

> +	bool level_match = (opp_key.level == OPP_LEVEL_UNSET ||
> +			    key.level == OPP_LEVEL_UNSET || opp_key.level == key.level);

We should compare bw too I guess in the same routine.

> +	if (freq_match && level_match) {
> +		*opp = temp_opp;
> +		return true;
> +	}
> +
> +	return false;
> +}
> +/**
> + * dev_pm_opp_find_freq_level_exact() - Search for an exact frequency and level

Instead dev_pm_opp_find_key_exact() and let the user pass the key
struct itself.

> +struct dev_pm_opp *dev_pm_opp_find_freq_level_exact(struct device *dev,
> +						    unsigned long freq,
> +						    unsigned int level,
> +						    bool available)
> +{
> +	struct opp_table *opp_table __free(put_opp_table);

The constructor here must be real, i.e. initialize opp_table here
itself. This is well documented in cleanup.h. Yes there are examples
like this in the OPP core which are required to be fixed too.

-- 
viresh