On Thu, Jun 29, 2023 at 09:54:54PM +0800, Limonciello, Mario wrote:
> Some applications may want to query the base frequency to tell when
> a processor is operating in boost.
>
> Tested-by: Wyes Karny <wyes.karny@xxxxxxx>
> Reviewed-by: Wyes Karny <wyes.karny@xxxxxxx>
> Co-developed-by: Perry Yuan <perry.yuan@xxxxxxx>
> Signed-off-by: Perry Yuan <perry.yuan@xxxxxxx>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> ---
> Documentation/admin-guide/pm/amd-pstate.rst | 4 ++++
> drivers/cpufreq/amd-pstate.c | 15 +++++++++++++++
> 2 files changed, 19 insertions(+)
>
> diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
> index 1cf40f69278cd..e68267857e859 100644
> --- a/Documentation/admin-guide/pm/amd-pstate.rst
> +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> @@ -281,6 +281,10 @@ integer values defined between 0 to 255 when EPP feature is enabled by platform
> firmware, if EPP feature is disabled, driver will ignore the written value
> This attribute is read-write.
>
> +``base_frequency``
> + Shows the base frequency of the CPU. Frequencies above this will be in the
> + ``boost`` range. This attribute is read-only.
> +
> Other performance and frequency values can be read back from
> ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 81fba0dcbee99..0fec66b3f7241 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -1037,6 +1037,19 @@ static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
> return ret < 0 ? ret : count;
> }
>
> +static ssize_t show_base_frequency(struct cpufreq_policy *policy, char *buf)
> +{
> + struct amd_cpudata *cpudata = policy->driver_data;
> + u32 nominal_freq;
> +
> + nominal_freq = amd_get_nominal_freq(cpudata);
> + if (nominal_freq < 0)
> + return nominal_freq;
> +
> + return sysfs_emit(buf, "%d\n", nominal_freq);
> +}
User can get it from nominal_freq at drivers/acpi/cppc_acpi.c:
show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq);
Thanks,
Ray
> +
> +cpufreq_freq_attr_ro(base_frequency);
> cpufreq_freq_attr_ro(amd_pstate_max_freq);
> cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>
> @@ -1049,6 +1062,7 @@ static struct freq_attr *amd_pstate_attr[] = {
> &amd_pstate_max_freq,
> &amd_pstate_lowest_nonlinear_freq,
> &amd_pstate_highest_perf,
> + &base_frequency,
> NULL,
> };
>
> @@ -1058,6 +1072,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
> &amd_pstate_highest_perf,
> &energy_performance_preference,
> &energy_performance_available_preferences,
> + &base_frequency,
> NULL,
> };
>
> --
> 2.34.1
>
