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Commit a82fab29 authored by Srivatsa S. Bhat's avatar Srivatsa S. Bhat Committed by Rafael J. Wysocki
Browse files

cpufreq: Introduce a flag ('frozen') to separate full vs temporary init/teardown 



During suspend/resume we would like to do a light-weight init/teardown of
CPUs in the cpufreq subsystem and preserve certain things such as sysfs files
etc across suspend/resume transitions. Add a flag called 'frozen' to help
distinguish the full init/teardown sequence from the light-weight one.

Signed-off-by: default avatarSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent f9ba680d

drivers/cpufreq/cpufreq.c

+49 −27
Original line number Diff line number Diff line
@@ -903,7 +903,7 @@ static void cpufreq_init_policy(struct cpufreq_policy *policy) 


#ifdef CONFIG_HOTPLUG_CPU

static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,

				  struct device *dev)

				  struct device *dev, bool frozen)

{

	struct cpufreq_policy *policy;

	int ret = 0, has_target = !!cpufreq_driver->target;
@@ -931,13 +931,18 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, 
		__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);

	}



	ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");

	if (ret) {

	/* Don't touch sysfs links during light-weight init */

	if (frozen) {

		/* Drop the extra refcount that we took above */

		cpufreq_cpu_put(policy);

		return ret;

		return 0;

	}



	return 0;

	ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");

	if (ret)

		cpufreq_cpu_put(policy);



	return ret;

}

#endif
@@ -972,16 +977,8 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) 
	kfree(policy);

}



/**

 * cpufreq_add_dev - add a CPU device

 *

 * Adds the cpufreq interface for a CPU device.

 *

 * The Oracle says: try running cpufreq registration/unregistration concurrently

 * with with cpu hotplugging and all hell will break loose. Tried to clean this

 * mess up, but more thorough testing is needed. - Mathieu

 */

static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)

static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,

			     bool frozen)

{

	unsigned int j, cpu = dev->id;

	int ret = -ENOMEM;
@@ -1013,7 +1010,8 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 
		struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);

		if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) {

			read_unlock_irqrestore(&cpufreq_driver_lock, flags);

			return cpufreq_add_policy_cpu(cpu, sibling, dev);

			return cpufreq_add_policy_cpu(cpu, sibling, dev,

						      frozen);

		}

	}

	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
@@ -1079,9 +1077,11 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 
	}

	write_unlock_irqrestore(&cpufreq_driver_lock, flags);



	if (!frozen) {

		ret = cpufreq_add_dev_interface(cpu, policy, dev);

		if (ret)

			goto err_out_unregister;

	}



	cpufreq_init_policy(policy);
@@ -1112,6 +1112,20 @@ module_out: 
	return ret;

}



/**

 * cpufreq_add_dev - add a CPU device

 *

 * Adds the cpufreq interface for a CPU device.

 *

 * The Oracle says: try running cpufreq registration/unregistration concurrently

 * with with cpu hotplugging and all hell will break loose. Tried to clean this

 * mess up, but more thorough testing is needed. - Mathieu

 */

static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)

{

	return __cpufreq_add_dev(dev, sif, false);

}



static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)

{

	int j;
@@ -1130,7 +1144,7 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) 
}



static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data,

					   unsigned int old_cpu)

					   unsigned int old_cpu, bool frozen)

{

	struct device *cpu_dev;

	unsigned long flags;
@@ -1138,6 +1152,11 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data, 


	/* first sibling now owns the new sysfs dir */

	cpu_dev = get_cpu_device(cpumask_first(data->cpus));



	/* Don't touch sysfs files during light-weight tear-down */

	if (frozen)

		return cpu_dev->id;



	sysfs_remove_link(&cpu_dev->kobj, "cpufreq");

	ret = kobject_move(&data->kobj, &cpu_dev->kobj);

	if (ret) {
@@ -1169,7 +1188,7 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data, 
 * This routine frees the rwsem before returning.

 */

static int __cpufreq_remove_dev(struct device *dev,

		struct subsys_interface *sif)

				struct subsys_interface *sif, bool frozen)

{

	unsigned int cpu = dev->id, cpus;

	int new_cpu;
@@ -1208,19 +1227,22 @@ static int __cpufreq_remove_dev(struct device *dev, 
		cpumask_clear_cpu(cpu, data->cpus);

	unlock_policy_rwsem_write(cpu);



	if (cpu != data->cpu) {

	if (cpu != data->cpu && !frozen) {

		sysfs_remove_link(&dev->kobj, "cpufreq");

	} else if (cpus > 1) {



		new_cpu = cpufreq_nominate_new_policy_cpu(data, cpu);

		new_cpu = cpufreq_nominate_new_policy_cpu(data, cpu, frozen);

		if (new_cpu >= 0) {

			WARN_ON(lock_policy_rwsem_write(cpu));

			update_policy_cpu(data, new_cpu);

			unlock_policy_rwsem_write(cpu);



			if (!frozen) {

				pr_debug("%s: policy Kobject moved to cpu: %d "

					 "from: %d\n",__func__, new_cpu, cpu);

			}

		}

	}



	/* If cpu is last user of policy, free policy */

	if (cpus == 1) {
@@ -1266,7 +1288,7 @@ static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) 
	if (cpu_is_offline(cpu))

		return 0;



	retval = __cpufreq_remove_dev(dev, sif);

	retval = __cpufreq_remove_dev(dev, sif, false);

	return retval;

}
@@ -1992,7 +2014,7 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, 
			break;

		case CPU_DOWN_PREPARE:

		case CPU_DOWN_PREPARE_FROZEN:

			__cpufreq_remove_dev(dev, NULL);

			__cpufreq_remove_dev(dev, NULL, false);

			break;

		case CPU_DOWN_FAILED:

		case CPU_DOWN_FAILED_FROZEN: