Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 262 insertions, 0 deletions

diff --git a/Documentation/power/powercap/powercap.rst b/Documentation/power/powercap/powercap.rst
new file mode 100644
index 000000000..e75d12596
--- /dev/null
+++ b/Documentation/power/powercap/powercap.rst
@@ -0,0 +1,262 @@
+=======================
+Power Capping Framework
+=======================
+
+The power capping framework provides a consistent interface between the kernel
+and the user space that allows power capping drivers to expose the settings to
+user space in a uniform way.
+
+Terminology
+===========
+
+The framework exposes power capping devices to user space via sysfs in the
+form of a tree of objects. The objects at the root level of the tree represent
+'control types', which correspond to different methods of power capping.  For
+example, the intel-rapl control type represents the Intel "Running Average
+Power Limit" (RAPL) technology, whereas the 'idle-injection' control type
+corresponds to the use of idle injection for controlling power.
+
+Power zones represent different parts of the system, which can be controlled and
+monitored using the power capping method determined by the control type the
+given zone belongs to. They each contain attributes for monitoring power, as
+well as controls represented in the form of power constraints.  If the parts of
+the system represented by different power zones are hierarchical (that is, one
+bigger part consists of multiple smaller parts that each have their own power
+controls), those power zones may also be organized in a hierarchy with one
+parent power zone containing multiple subzones and so on to reflect the power
+control topology of the system.  In that case, it is possible to apply power
+capping to a set of devices together using the parent power zone and if more
+fine grained control is required, it can be applied through the subzones.
+
+
+Example sysfs interface tree::
+
+  /sys/devices/virtual/powercap
+  └──intel-rapl
+      ├──intel-rapl:0
+      │   ├──constraint_0_name
+      │   ├──constraint_0_power_limit_uw
+      │   ├──constraint_0_time_window_us
+      │   ├──constraint_1_name
+      │   ├──constraint_1_power_limit_uw
+      │   ├──constraint_1_time_window_us
+      │   ├──device -> ../../intel-rapl
+      │   ├──energy_uj
+      │   ├──intel-rapl:0:0
+      │   │   ├──constraint_0_name
+      │   │   ├──constraint_0_power_limit_uw
+      │   │   ├──constraint_0_time_window_us
+      │   │   ├──constraint_1_name
+      │   │   ├──constraint_1_power_limit_uw
+      │   │   ├──constraint_1_time_window_us
+      │   │   ├──device -> ../../intel-rapl:0
+      │   │   ├──energy_uj
+      │   │   ├──max_energy_range_uj
+      │   │   ├──name
+      │   │   ├──enabled
+      │   │   ├──power
+      │   │   │   ├──async
+      │   │   │   []
+      │   │   ├──subsystem -> ../../../../../../class/power_cap
+      │   │   └──uevent
+      │   ├──intel-rapl:0:1
+      │   │   ├──constraint_0_name
+      │   │   ├──constraint_0_power_limit_uw
+      │   │   ├──constraint_0_time_window_us
+      │   │   ├──constraint_1_name
+      │   │   ├──constraint_1_power_limit_uw
+      │   │   ├──constraint_1_time_window_us
+      │   │   ├──device -> ../../intel-rapl:0
+      │   │   ├──energy_uj
+      │   │   ├──max_energy_range_uj
+      │   │   ├──name
+      │   │   ├──enabled
+      │   │   ├──power
+      │   │   │   ├──async
+      │   │   │   []
+      │   │   ├──subsystem -> ../../../../../../class/power_cap
+      │   │   └──uevent
+      │   ├──max_energy_range_uj
+      │   ├──max_power_range_uw
+      │   ├──name
+      │   ├──enabled
+      │   ├──power
+      │   │   ├──async
+      │   │   []
+      │   ├──subsystem -> ../../../../../class/power_cap
+      │   ├──enabled
+      │   ├──uevent
+      ├──intel-rapl:1
+      │   ├──constraint_0_name
+      │   ├──constraint_0_power_limit_uw
+      │   ├──constraint_0_time_window_us
+      │   ├──constraint_1_name
+      │   ├──constraint_1_power_limit_uw
+      │   ├──constraint_1_time_window_us
+      │   ├──device -> ../../intel-rapl
+      │   ├──energy_uj
+      │   ├──intel-rapl:1:0
+      │   │   ├──constraint_0_name
+      │   │   ├──constraint_0_power_limit_uw
+      │   │   ├──constraint_0_time_window_us
+      │   │   ├──constraint_1_name
+      │   │   ├──constraint_1_power_limit_uw
+      │   │   ├──constraint_1_time_window_us
+      │   │   ├──device -> ../../intel-rapl:1
+      │   │   ├──energy_uj
+      │   │   ├──max_energy_range_uj
+      │   │   ├──name
+      │   │   ├──enabled
+      │   │   ├──power
+      │   │   │   ├──async
+      │   │   │   []
+      │   │   ├──subsystem -> ../../../../../../class/power_cap
+      │   │   └──uevent
+      │   ├──intel-rapl:1:1
+      │   │   ├──constraint_0_name
+      │   │   ├──constraint_0_power_limit_uw
+      │   │   ├──constraint_0_time_window_us
+      │   │   ├──constraint_1_name
+      │   │   ├──constraint_1_power_limit_uw
+      │   │   ├──constraint_1_time_window_us
+      │   │   ├──device -> ../../intel-rapl:1
+      │   │   ├──energy_uj
+      │   │   ├──max_energy_range_uj
+      │   │   ├──name
+      │   │   ├──enabled
+      │   │   ├──power
+      │   │   │   ├──async
+      │   │   │   []
+      │   │   ├──subsystem -> ../../../../../../class/power_cap
+      │   │   └──uevent
+      │   ├──max_energy_range_uj
+      │   ├──max_power_range_uw
+      │   ├──name
+      │   ├──enabled
+      │   ├──power
+      │   │   ├──async
+      │   │   []
+      │   ├──subsystem -> ../../../../../class/power_cap
+      │   ├──uevent
+      ├──power
+      │   ├──async
+      │   []
+      ├──subsystem -> ../../../../class/power_cap
+      ├──enabled
+      └──uevent
+
+The above example illustrates a case in which the Intel RAPL technology,
+available in Intel® IA-64 and IA-32 Processor Architectures, is used. There is one
+control type called intel-rapl which contains two power zones, intel-rapl:0 and
+intel-rapl:1, representing CPU packages.  Each of these power zones contains
+two subzones, intel-rapl:j:0 and intel-rapl:j:1 (j = 0, 1), representing the
+"core" and the "uncore" parts of the given CPU package, respectively.  All of
+the zones and subzones contain energy monitoring attributes (energy_uj,
+max_energy_range_uj) and constraint attributes (constraint_*) allowing controls
+to be applied (the constraints in the 'package' power zones apply to the whole
+CPU packages and the subzone constraints only apply to the respective parts of
+the given package individually). Since Intel RAPL doesn't provide instantaneous
+power value, there is no power_uw attribute.
+
+In addition to that, each power zone contains a name attribute, allowing the
+part of the system represented by that zone to be identified.
+For example::
+
+	cat /sys/class/power_cap/intel-rapl/intel-rapl:0/name
+
+package-0
+---------
+
+Depending on different power zones, the Intel RAPL technology allows
+one or multiple constraints like short term, long term and peak power,
+with different time windows to be applied to each power zone.
+All the zones contain attributes representing the constraint names,
+power limits and the sizes of the time windows. Note that time window
+is not applicable to peak power. Here, constraint_j_* attributes
+correspond to the jth constraint (j = 0,1,2).
+
+For example::
+
+	constraint_0_name
+	constraint_0_power_limit_uw
+	constraint_0_time_window_us
+	constraint_1_name
+	constraint_1_power_limit_uw
+	constraint_1_time_window_us
+	constraint_2_name
+	constraint_2_power_limit_uw
+	constraint_2_time_window_us
+
+Power Zone Attributes
+=====================
+
+Monitoring attributes
+---------------------
+
+energy_uj (rw)
+	Current energy counter in micro joules. Write "0" to reset.
+	If the counter can not be reset, then this attribute is read only.
+
+max_energy_range_uj (ro)
+	Range of the above energy counter in micro-joules.
+
+power_uw (ro)
+	Current power in micro watts.
+
+max_power_range_uw (ro)
+	Range of the above power value in micro-watts.
+
+name (ro)
+	Name of this power zone.
+
+It is possible that some domains have both power ranges and energy counter ranges;
+however, only one is mandatory.
+
+Constraints
+-----------
+
+constraint_X_power_limit_uw (rw)
+	Power limit in micro watts, which should be applicable for the
+	time window specified by "constraint_X_time_window_us".
+
+constraint_X_time_window_us (rw)
+	Time window in micro seconds.
+
+constraint_X_name (ro)
+	An optional name of the constraint
+
+constraint_X_max_power_uw(ro)
+	Maximum allowed power in micro watts.
+
+constraint_X_min_power_uw(ro)
+	Minimum allowed power in micro watts.
+
+constraint_X_max_time_window_us(ro)
+	Maximum allowed time window in micro seconds.
+
+constraint_X_min_time_window_us(ro)
+	Minimum allowed time window in micro seconds.
+
+Except power_limit_uw and time_window_us other fields are optional.
+
+Common zone and control type attributes
+---------------------------------------
+
+enabled (rw): Enable/Disable controls at zone level or for all zones using
+a control type.
+
+Power Cap Client Driver Interface
+=================================
+
+The API summary:
+
+Call powercap_register_control_type() to register control type object.
+Call powercap_register_zone() to register a power zone (under a given
+control type), either as a top-level power zone or as a subzone of another
+power zone registered earlier.
+The number of constraints in a power zone and the corresponding callbacks have
+to be defined prior to calling powercap_register_zone() to register that zone.
+
+To Free a power zone call powercap_unregister_zone().
+To free a control type object call powercap_unregister_control_type().
+Detailed API can be generated using kernel-doc on include/linux/powercap.h.