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);
+}
+
+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
