Re: [PATCH] cpufreq: qcom-hw: Fix reading "reg" with address/size-cells != 2

[Viresh Kumar]

On 09-12-22, 16:07, Konrad Dybcio wrote:
> Commit 054a3ef683a1 ("cpufreq: qcom-hw: Allocate qcom_cpufreq_data during
> probe") assumed that every reg variable is 4*u32 wide (as most new qcom

                                                        corresponding ")" is missing.

> SoCs set #address- and #size-cells to <2>. That is not the case for all of
> them though. Check the cells values dynamically to ensure the proper
> region of the DTB is being read.
> 
> Fixes: 054a3ef683a1 ("cpufreq: qcom-hw: Allocate qcom_cpufreq_data during probe")
> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
> ---
>  drivers/cpufreq/qcom-cpufreq-hw.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index 340fed35e45d..22f48f789557 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -649,9 +649,10 @@ static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
>  {
>  	struct clk_hw_onecell_data *clk_data;
>  	struct device *dev = &pdev->dev;
> +	struct device_node *soc_node;
>  	struct device *cpu_dev;
>  	struct clk *clk;
> -	int ret, i, num_domains;
> +	int ret, i, num_domains, reg_sz;
>  
>  	clk = clk_get(dev, "xo");
>  	if (IS_ERR(clk))
> @@ -679,7 +680,22 @@ static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
>  		return ret;
>  
>  	/* Allocate qcom_cpufreq_data based on the available frequency domains in DT */
> -	num_domains = of_property_count_elems_of_size(dev->of_node, "reg", sizeof(u32) * 4);
> +	soc_node = of_get_parent(dev->of_node);

This must be dropped on failures later ?

> +	if (!soc_node)
> +		return -EINVAL;
> +
> +	ret = of_property_read_u32(soc_node, "#address-cells", &reg_sz);
> +	if (ret)
> +		return ret;
> +
> +	/* Reuse 'i', as it's only used later in the loop */

This can be dropped in my opinion.

> +	ret = of_property_read_u32(soc_node, "#size-cells", &i);

Should i be initialized ?

> +	if (ret)
> +		return ret;
> +
> +	reg_sz += i;
> +
> +	num_domains = of_property_count_elems_of_size(dev->of_node, "reg", sizeof(u32) * reg_sz);
>  	if (num_domains <= 0)
>  		return num_domains;
>  
> -- 
> 2.38.1

-- 
viresh