Commit abd61c08 authored by Perry Yuan's avatar Perry Yuan Committed by Rafael J. Wysocki
Browse files

cpufreq: amd-pstate: add driver working mode switch support 



While amd-pstate driver was loaded with specific driver mode, it will
need to check which mode is enabled for the pstate driver,add this sysfs
entry to show the current status

$ cat /sys/devices/system/cpu/amd-pstate/status
active

Meanwhile, user can switch the pstate driver mode with writing mode
string to sysfs entry as below.

Enable passive mode:
$ sudo bash -c "echo passive >  /sys/devices/system/cpu/amd-pstate/status"

Enable active mode (EPP driver mode):
$ sudo bash -c "echo active > /sys/devices/system/cpu/amd-pstate/status"

Acked-by: default avatarHuang Rui <ray.huang@amd.com>
Reviewed-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Reviewed-by: default avatarWyes Karny <wyes.karny@amd.com>
Tested-by: default avatarWyes Karny <wyes.karny@amd.com>
Signed-off-by: default avatarPerry Yuan <Perry.Yuan@amd.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 50ddd2f7

drivers/cpufreq/amd-pstate.c

+118 −0
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ static struct cpufreq_driver *current_pstate_driver; 
static struct cpufreq_driver amd_pstate_driver;

static struct cpufreq_driver amd_pstate_epp_driver;

static int cppc_state = AMD_PSTATE_DISABLE;

struct kobject *amd_pstate_kobj;



/*

 * AMD Energy Preference Performance (EPP)
@@ -673,6 +674,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy) 
	policy->driver_data = cpudata;



	amd_pstate_boost_init(cpudata);

	if (!current_pstate_driver->adjust_perf)

		current_pstate_driver->adjust_perf = amd_pstate_adjust_perf;



	return 0;
@@ -813,12 +816,99 @@ static ssize_t show_energy_performance_preference( 
	return sysfs_emit(buf, "%s\n", energy_perf_strings[preference]);

}



static ssize_t amd_pstate_show_status(char *buf)

{

	if (!current_pstate_driver)

		return sysfs_emit(buf, "disable\n");



	return sysfs_emit(buf, "%s\n", amd_pstate_mode_string[cppc_state]);

}



static void amd_pstate_driver_cleanup(void)

{

	current_pstate_driver = NULL;

}



static int amd_pstate_update_status(const char *buf, size_t size)

{

	int ret;

	int mode_idx;



	if (size > 7 || size < 6)

		return -EINVAL;

	mode_idx = get_mode_idx_from_str(buf, size);



	switch(mode_idx) {

	case AMD_PSTATE_DISABLE:

		if (!current_pstate_driver)

			return -EINVAL;

		if (cppc_state == AMD_PSTATE_ACTIVE)

			return -EBUSY;

		ret = cpufreq_unregister_driver(current_pstate_driver);

		amd_pstate_driver_cleanup();

		break;

	case AMD_PSTATE_PASSIVE:

		if (current_pstate_driver) {

			if (current_pstate_driver == &amd_pstate_driver)

				return 0;

			cpufreq_unregister_driver(current_pstate_driver);

			cppc_state = AMD_PSTATE_PASSIVE;

			current_pstate_driver = &amd_pstate_driver;

		}



		ret = cpufreq_register_driver(current_pstate_driver);

		break;

	case AMD_PSTATE_ACTIVE:

		if (current_pstate_driver) {

			if (current_pstate_driver == &amd_pstate_epp_driver)

				return 0;

			cpufreq_unregister_driver(current_pstate_driver);

			current_pstate_driver = &amd_pstate_epp_driver;

			cppc_state = AMD_PSTATE_ACTIVE;

		}



		ret = cpufreq_register_driver(current_pstate_driver);

		break;

	default:

		ret = -EINVAL;

		break;

	}



	return ret;

}



static ssize_t show_status(struct kobject *kobj,

			   struct kobj_attribute *attr, char *buf)

{

	ssize_t ret;



	mutex_lock(&amd_pstate_driver_lock);

	ret = amd_pstate_show_status(buf);

	mutex_unlock(&amd_pstate_driver_lock);



	return ret;

}



static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,

			    const char *buf, size_t count)

{

	char *p = memchr(buf, '\n', count);

	int ret;



	mutex_lock(&amd_pstate_driver_lock);

	ret = amd_pstate_update_status(buf, p ? p - buf : count);

	mutex_unlock(&amd_pstate_driver_lock);



	return ret < 0 ? ret : count;

}



cpufreq_freq_attr_ro(amd_pstate_max_freq);

cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);



cpufreq_freq_attr_ro(amd_pstate_highest_perf);

cpufreq_freq_attr_rw(energy_performance_preference);

cpufreq_freq_attr_ro(energy_performance_available_preferences);

define_one_global_rw(status);



static struct freq_attr *amd_pstate_attr[] = {

	&amd_pstate_max_freq,
@@ -836,6 +926,15 @@ static struct freq_attr *amd_pstate_epp_attr[] = { 
	NULL,

};



static struct attribute *pstate_global_attributes[] = {

	&status.attr,

	NULL

};



static const struct attribute_group amd_pstate_global_attr_group = {

	.attrs = pstate_global_attributes,

};



static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)

{

	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
@@ -1200,6 +1299,25 @@ static int __init amd_pstate_init(void) 
	if (ret)

		pr_err("failed to register with return %d\n", ret);



	amd_pstate_kobj = kobject_create_and_add("amd_pstate", &cpu_subsys.dev_root->kobj);

	if (!amd_pstate_kobj) {

		ret = -EINVAL;

		pr_err("global sysfs registration failed.\n");

		goto kobject_free;

	}



	ret = sysfs_create_group(amd_pstate_kobj, &amd_pstate_global_attr_group);

	if (ret) {

		pr_err("sysfs attribute export failed with error %d.\n", ret);

		goto global_attr_free;

	}



	return ret;



global_attr_free:

	kobject_put(amd_pstate_kobj);

kobject_free:

	cpufreq_unregister_driver(current_pstate_driver);

	return ret;

}

device_initcall(amd_pstate_init);