Commit 67fc209b authored by Shawn Guo's avatar Shawn Guo Committed by Viresh Kumar
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cpufreq: qcom-hw: drop devm_xxx() calls from init/exit hooks 



Commit f17b3e44 ("cpufreq: qcom-hw: Use
devm_platform_ioremap_resource() to simplify code") introduces
a regression on platforms using the driver, by failing to initialise
a policy, when one is created post hotplug.

When all the CPUs of a policy are hoptplugged out, the call to .exit()
and later to devm_iounmap() does not release the memory region that was
requested during devm_platform_ioremap_resource().  Therefore,
a subsequent call to .init() will result in the following error, which
will prevent a new policy to be initialised:

[ 3395.915416] CPU4: shutdown
[ 3395.938185] psci: CPU4 killed (polled 0 ms)
[ 3399.071424] CPU5: shutdown
[ 3399.094316] psci: CPU5 killed (polled 0 ms)
[ 3402.139358] CPU6: shutdown
[ 3402.161705] psci: CPU6 killed (polled 0 ms)
[ 3404.742939] CPU7: shutdown
[ 3404.765592] psci: CPU7 killed (polled 0 ms)
[ 3411.492274] Detected VIPT I-cache on CPU4
[ 3411.492337] GICv3: CPU4: found redistributor 400 region 0:0x0000000017ae0000
[ 3411.492448] CPU4: Booted secondary processor 0x0000000400 [0x516f802d]
[ 3411.503654] qcom-cpufreq-hw 17d43000.cpufreq: can't request region for resource [mem 0x17d45800-0x17d46bff]

With that being said, the original code was tricky and skipping memory
region request intentionally to hide this issue.  The true cause is that
those devm_xxx() device managed functions shouldn't be used for cpufreq
init/exit hooks, because &pdev->dev is alive across the hooks and will
not trigger auto resource free-up.  Let's drop the use of device managed
functions and manually allocate/free resources, so that the issue can be
fixed properly.

Cc: v5.10+ <stable@vger.kernel.org> # v5.10+
Fixes: f17b3e44 ("cpufreq: qcom-hw: Use devm_platform_ioremap_resource() to simplify code")
Suggested-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
parent 7114ebff

drivers/cpufreq/qcom-cpufreq-hw.c

+32 −8
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ struct qcom_cpufreq_soc_data { 


struct qcom_cpufreq_data {

	void __iomem *base;

	struct resource *res;

	const struct qcom_cpufreq_soc_data *soc_data;

};
@@ -280,6 +281,7 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy) 
	struct of_phandle_args args;

	struct device_node *cpu_np;

	struct device *cpu_dev;

	struct resource *res;

	void __iomem *base;

	struct qcom_cpufreq_data *data;

	int ret, index;
@@ -303,18 +305,33 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy) 


	index = args.args[0];



	base = devm_platform_ioremap_resource(pdev, index);

	if (IS_ERR(base))

		return PTR_ERR(base);

	res = platform_get_resource(pdev, IORESOURCE_MEM, index);

	if (!res) {

		dev_err(dev, "failed to get mem resource %d\n", index);

		return -ENODEV;

	}



	if (!request_mem_region(res->start, resource_size(res), res->name)) {

		dev_err(dev, "failed to request resource %pR\n", res);

		return -EBUSY;

	}



	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);

	base = ioremap(res->start, resource_size(res));

	if (IS_ERR(base)) {

		dev_err(dev, "failed to map resource %pR\n", res);

		ret = PTR_ERR(base);

		goto release_region;

	}



	data = kzalloc(sizeof(*data), GFP_KERNEL);

	if (!data) {

		ret = -ENOMEM;

		goto error;

		goto unmap_base;

	}



	data->soc_data = of_device_get_match_data(&pdev->dev);

	data->base = base;

	data->res = res;



	/* HW should be in enabled state to proceed */

	if (!(readl_relaxed(base + data->soc_data->reg_enable) & 0x1)) {
@@ -355,7 +372,11 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy) 


	return 0;

error:

	devm_iounmap(dev, base);

	kfree(data);

unmap_base:

	iounmap(data->base);

release_region:

	release_mem_region(res->start, resource_size(res));

	return ret;

}
@@ -363,12 +384,15 @@ static int qcom_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy) 
{

	struct device *cpu_dev = get_cpu_device(policy->cpu);

	struct qcom_cpufreq_data *data = policy->driver_data;

	struct platform_device *pdev = cpufreq_get_driver_data();

	struct resource *res = data->res;

	void __iomem *base = data->base;



	dev_pm_opp_remove_all_dynamic(cpu_dev);

	dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);

	kfree(policy->freq_table);

	devm_iounmap(&pdev->dev, data->base);

	kfree(data);

	iounmap(base);

	release_mem_region(res->start, resource_size(res));



	return 0;

}