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

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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: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Perry Yuan 2023-01-31 17:00:12 +08:00 committed by Rafael J. Wysocki
parent 50ddd2f782
commit abd61c08ef
1 changed files with 118 additions and 0 deletions
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118
drivers/cpufreq/amd-pstate.c
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@ -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);