Merge back cpufreq material for 6.3-rc1.

2 files changed, 79 insertions, 2 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6cfa6e3996cf..e3618dfdb36a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -7020,3 +7020,10 @@
 			  management firmware translates the requests into actual
 			  hardware states (core frequency, data fabric and memory
 			  clocks etc.)
+			active
+			  Use amd_pstate_epp driver instance as the scaling driver,
+			  driver provides a hint to the hardware if software wants
+			  to bias toward performance (0x0) or energy efficiency (0xff)
+			  to the CPPC firmware. then CPPC power algorithm will
+			  calculate the runtime workload and adjust the realtime cores
+			  frequency.
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 5376d53faaa8..5304adf2fc2f 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -262,6 +262,25 @@ lowest non-linear performance in `AMD CPPC Performance Capability
 <perf_cap_>`_.)
 This attribute is read-only.
 
+``energy_performance_available_preferences``
+
+A list of all the supported EPP preferences that could be used for
+``energy_performance_preference`` on this system.
+These profiles represent different hints that are provided
+to the low-level firmware about the user's desired energy vs efficiency
+tradeoff.  ``default`` represents the epp value is set by platform
+firmware. This attribute is read-only.
+
+``energy_performance_preference``
+
+The current energy performance preference can be read from this attribute.
+and user can change current preference according to energy or performance needs
+Please get all support profiles list from
+``energy_performance_available_preferences`` attribute, all the profiles are
+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.
+
 Other performance and frequency values can be read back from
 ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
 
@@ -280,8 +299,30 @@ module which supports the new AMD P-States mechanism on most of the future AMD
 platforms. The AMD P-States mechanism is the more performance and energy
 efficiency frequency management method on AMD processors.
 
-Kernel Module Options for ``amd-pstate``
-=========================================
+
+AMD Pstate Driver Operation Modes
+=================================
+
+``amd_pstate`` CPPC has two operation modes: CPPC Autonomous(active) mode and
+CPPC non-autonomous(passive) mode.
+active mode and passive mode can be chosen by different kernel parameters.
+When in Autonomous mode, CPPC ignores requests done in the Desired Performance
+Target register and takes into account only the values set to the Minimum requested
+performance, Maximum requested performance, and Energy Performance Preference
+registers. When Autonomous is disabled, it only considers the Desired Performance Target.
+
+Active Mode
+------------
+
+``amd_pstate=active``
+
+This is the low-level firmware control mode which is implemented by ``amd_pstate_epp``
+driver with ``amd_pstate=active`` passed to the kernel in the command line.
+In this mode, ``amd_pstate_epp`` driver provides a hint to the hardware if software
+wants to bias toward performance (0x0) or energy efficiency (0xff) to the CPPC firmware.
+then CPPC power algorithm will calculate the runtime workload and adjust the realtime
+cores frequency according to the power supply and thermal, core voltage and some other
+hardware conditions.
 
 Passive Mode
 ------------
@@ -298,6 +339,35 @@ processor must provide at least nominal performance requested and go higher if c
 operating conditions allow.
 
 
+User Space Interface in ``sysfs``
+=================================
+
+Global Attributes
+-----------------
+
+``amd-pstate`` exposes several global attributes (files) in ``sysfs`` to
+control its functionality at the system level.  They are located in the
+``/sys/devices/system/cpu/amd-pstate/`` directory and affect all CPUs.
+
+``status``
+	Operation mode of the driver: "active", "passive" or "disable".
+
+	"active"
+		The driver is functional and in the ``active mode``
+
+	"passive"
+		The driver is functional and in the ``passive mode``
+
+	"disable"
+		The driver is unregistered and not functional now.
+
+        This attribute can be written to in order to change the driver's
+        operation mode or to unregister it.  The string written to it must be
+        one of the possible values of it and, if successful, writing one of
+        these values to the sysfs file will cause the driver to switch over
+        to the operation mode represented by that string - or to be
+        unregistered in the "disable" case.
+
 ``cpupower`` tool support for ``amd-pstate``
 ===============================================