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Commit 2b63b109 authored by Junjie Wu's avatar Junjie Wu
Browse files

qcom-cpufreq: Block hotplug until cpufreq is ready 



Hotplug before qcom-cpufreq is ready could lead to inconsistent CPU
clock state. Block hotplug by returning NOTIFY_BAD in hotplug callback
until qcom-cpufreq is probed.

Change-Id: I72a2f98c083c9b21b95ecafdb5a5be7a7682e842
Signed-off-by: default avatarJunjie Wu <junjiew@codeaurora.org>
parent 360013b1

drivers/cpufreq/qcom-cpufreq.c

+22 −3
Original line number Diff line number Diff line
@@ -294,6 +294,10 @@ static int msm_cpufreq_cpu_callback(struct notifier_block *nfb, 
	unsigned int cpu = (unsigned long)hcpu;

	int rc;



	/* Fail hotplug until this driver can get CPU clocks */

	if (!cpu_clk[0])

		return NOTIFY_BAD;



	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_ONLINE:

		per_cpu(cpufreq_suspend, cpu).device_suspended = 0;
@@ -587,18 +591,33 @@ static struct platform_driver msm_cpufreq_plat_driver = { 


static int __init msm_cpufreq_register(void)

{

	int cpu;

	int cpu, rc;



	for_each_possible_cpu(cpu) {

		mutex_init(&(per_cpu(cpufreq_suspend, cpu).suspend_mutex));

		per_cpu(cpufreq_suspend, cpu).device_suspended = 0;

	}



	platform_driver_probe(&msm_cpufreq_plat_driver, msm_cpufreq_probe);

	rc = platform_driver_probe(&msm_cpufreq_plat_driver,

				   msm_cpufreq_probe);

	if (rc < 0) {

		/* Unblock hotplug if msm-cpufreq probe fails */

		unregister_hotcpu_notifier(&msm_cpufreq_cpu_notifier);

		for_each_possible_cpu(cpu)

			mutex_destroy(&(per_cpu(cpufreq_suspend, cpu).

					suspend_mutex));

		return rc;

	}



	msm_cpufreq_wq = alloc_workqueue("msm-cpufreq", WQ_HIGHPRI, 0);

	register_hotcpu_notifier(&msm_cpufreq_cpu_notifier);

	register_pm_notifier(&msm_cpufreq_pm_notifier);

	return cpufreq_register_driver(&msm_cpufreq_driver);

}



subsys_initcall(msm_cpufreq_register);



static int __init msm_cpufreq_early_register(void)

{

	return register_hotcpu_notifier(&msm_cpufreq_cpu_notifier);

}

core_initcall(msm_cpufreq_early_register);