linux-kernel - Re: [PATCH v3 1/1] cpufreq: qcom-nvmem: add compatible fallback for ipq806x for no SMEM

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Message-ID: <d3f2810f-7361-4a23-adb3-32a73ad50519@kernel.org>
Date: Wed, 5 Nov 2025 09:05:57 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Christian Marangi <ansuelsmth@...il.com>, Ilia Lin <ilia.lin@...nel.org>,
 "Rafael J. Wysocki" <rafael@...nel.org>,
 Viresh Kumar <viresh.kumar@...aro.org>, linux-pm@...r.kernel.org,
 linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Subject: Re: [PATCH v3 1/1] cpufreq: qcom-nvmem: add compatible fallback for
 ipq806x for no SMEM

On 04/11/2025 15:06, 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.
> 
> Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
> Signed-off-by: Christian Marangi <ansuelsmth@...il.com>
> ---
>  drivers/cpufreq/qcom-cpufreq-nvmem.c | 35 ++++++++++++++++++++++++++--
>  1 file changed, 33 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/qcom-cpufreq-nvmem.c b/drivers/cpufreq/qcom-cpufreq-nvmem.c
> index 3a8ed723a23e..17c79955ff2f 100644
> --- a/drivers/cpufreq/qcom-cpufreq-nvmem.c
> +++ b/drivers/cpufreq/qcom-cpufreq-nvmem.c
> @@ -252,13 +252,22 @@ static int qcom_cpufreq_krait_name_version(struct device *cpu_dev,
>  	return ret;
>  }
>  
> +static const struct of_device_id qcom_cpufreq_ipq806x_match_list[] = {
> +	{ .compatible = "qcom,ipq8062", .data = (const void *)QCOM_ID_IPQ8062 },
> +	{ .compatible = "qcom,ipq8064", .data = (const void *)QCOM_ID_IPQ8064 },
> +	{ .compatible = "qcom,ipq8065", .data = (const void *)QCOM_ID_IPQ8065 },
> +	{ .compatible = "qcom,ipq8066", .data = (const void *)QCOM_ID_IPQ8066 },
> +	{ .compatible = "qcom,ipq8068", .data = (const void *)QCOM_ID_IPQ8068 },
> +	{ .compatible = "qcom,ipq8069", .data = (const void *)QCOM_ID_IPQ8069 },
> +};
> +
>  static int qcom_cpufreq_ipq8064_name_version(struct device *cpu_dev,
>  					     struct nvmem_cell *speedbin_nvmem,
>  					     char **pvs_name,
>  					     struct qcom_cpufreq_drv *drv)
>  {
> +	int msm_id = -1, ret = 0;
>  	int speed = 0, pvs = 0;
> -	int msm_id, ret = 0;
>  	u8 *speedbin;
>  	size_t len;
>  
> @@ -275,8 +284,30 @@ static int qcom_cpufreq_ipq8064_name_version(struct device *cpu_dev,
>  	get_krait_bin_format_a(cpu_dev, &speed, &pvs, speedbin);
>  
>  	ret = qcom_smem_get_soc_id(&msm_id);
> -	if (ret)
> +	if (ret == -ENODEV) {
> +		const struct of_device_id *match;
> +		struct device_node *root;
> +
> +		root = of_find_node_by_path("/");
> +		if (!root) {
> +			ret = -ENODEV;
> +			goto exit;
> +		}
> +
> +		/* Fallback to compatible match with no SMEM initialized */
> +		match = of_match_node(qcom_cpufreq_ipq806x_match_list, root);

Aren't you re-implementing matching machine? Or actually - the socinfo
driver? You are doing the matching of compatible into SOC ID second
time. Just do it once - via socinfo driver.

Best regards,
Krzysztof