Re: [PATCH v10 08/12] cpufreq: amd-pstate: add driver working mode switch support

Wyes Karny
2023-01-18T07:08:23Z

Hi Ray, Perry,

On 1/17/2023 7:26 PM, Huang Rui wrote:
> On Fri, Jan 06, 2023 at 02:14:16PM +0800, Yuan, Perry wrote:
>> From: Perry Yuan <Perry.Yuan@amd.com>
>>
>> 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"
>>
>> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
>> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
>
> Patch is Acked-by: Huang Rui <ray.huang@amd.com>
>
> Wyes, may we have a ack or any comment from you of this patch, as you are
> working on the new guided autonomous mode?

This looks good to me.

Reviewed-by: Wyes Karny <wyes.karny@amd.com>

>
> Thanks,
> Ray
>
>> ---
>> drivers/cpufreq/amd-pstate.c | 118 +++++++++++++++++++++++++++++++++++
>> 1 file changed, 118 insertions(+)
>>
>> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
>> index 2c8b126cec5a..d3f4cdd803f3 100644
>> --- a/drivers/cpufreq/amd-pstate.c
>> +++ b/drivers/cpufreq/amd-pstate.c
>> @@ -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;
>>
>> static inline int get_mode_idx_from_str(const char *str, size_t size)
>> {
>> @@ -631,6 +632,8 @@ 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;
>>
>> @@ -771,12 +774,99 @@ 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,
>> @@ -794,6 +884,15 @@ 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;
>> @@ -1153,6 +1252,25 @@ 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);
>> --
>> 2.34.1
>>

--
Thanks & Regards,
Wyes