linux-kernel - Re: [PATCH v2 3/3] cpufreq: qcom-nvmem: add compatible fallback for ipq806x for no SMEM

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Message-ID: <6904c563.050a0220.a13ee.0212@mx.google.com>
Date: Fri, 31 Oct 2025 15:19:12 +0100
From: Christian Marangi <ansuelsmth@...il.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Ilia Lin <ilia.lin@...nel.org>, "Rafael J. Wysocki" <rafael@...nel.org>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konradybcio@...nel.org>,
	Arnd Bergmann <arnd@...db.de>, Raag Jadav <raag.jadav@...el.com>,
	linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/3] cpufreq: qcom-nvmem: add compatible fallback for
 ipq806x for no SMEM

On Fri, Oct 31, 2025 at 03:26:46PM +0200, Andy Shevchenko wrote:
> On Fri, Oct 31, 2025 at 02:08:34PM +0100, Christian Marangi wrote:
> > On some IPQ806x SoC SMEM might be not initialized by SBL. This is the
> > case for some Google devices (the OnHub family) that can't make use of
> > SMEM to detect the SoC ID.
> > 
> > To handle these specific case, check if the SMEM is not initialized (by
> > checking if the qcom_smem_get_soc_id returns -ENODEV) and fallback to
> > OF machine compatible checking to identify the SoC variant.
> > 
> > Notice that the checking order is important as the machine compatible
> > are normally defined with the specific one following the generic SoC
> > (for example compatible = "qcom,ipq8065", "qcom,ipq8064").
> 
> ...
> 
> > +		if (of_machine_is_compatible("qcom,ipq8062"))
> > +			msm_id = QCOM_ID_IPQ8062;
> > +		else if (of_machine_is_compatible("qcom,ipq8065") ||
> > +			 of_machine_is_compatible("qcom,ipq8069"))
> > +			msm_id = QCOM_ID_IPQ8065;
> > +		else if (of_machine_is_compatible("qcom,ipq8064") ||
> > +			 of_machine_is_compatible("qcom,ipq8066") ||
> > +			 of_machine_is_compatible("qcom,ipq8068"))
> > +			msm_id = QCOM_ID_IPQ8064;
> 
> A nit-pick (in case you need a new version of the series): I would expect
> the conditionals be sorted by assigned value.
> 
> 		if (of_machine_is_compatible("qcom,ipq8062"))
> 			msm_id = QCOM_ID_IPQ8062;
> 		else if (of_machine_is_compatible("qcom,ipq8064") ||
> 			 of_machine_is_compatible("qcom,ipq8066") ||
> 			 of_machine_is_compatible("qcom,ipq8068"))
> 			msm_id = QCOM_ID_IPQ8064;
> 		else if (of_machine_is_compatible("qcom,ipq8065") ||
> 			 of_machine_is_compatible("qcom,ipq8069"))
> 			msm_id = QCOM_ID_IPQ8065;
>

Hi as said in the commit, parsing 65/69 before 64 is needed as we might
have compatible like

"qcom,ipq8065","qcom,ipq8064" so we might incorrectly parse msm_id
ipq8064.

> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

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