feat(mpmm): add support for MPMM
MPMM - the Maximum Power Mitigation Mechanism - is an optional
microarchitectural feature present on some Armv9-A cores, introduced
with the Cortex-X2, Cortex-A710 and Cortex-A510 cores.
MPMM allows the SoC firmware to detect and limit high activity events
to assist in SoC processor power domain dynamic power budgeting and
limit the triggering of whole-rail (i.e. clock chopping) responses to
overcurrent conditions.
This feature is enabled via the `ENABLE_MPMM` build option.
Configuration can be done via FCONF by enabling `ENABLE_MPMM_FCONF`, or
by via the plaform-implemented `plat_mpmm_topology` function.
Change-Id: I77da82808ad4744ece8263f0bf215c5a091c3167
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/docs/components/fconf/index.rst b/docs/components/fconf/index.rst
index 00a4e29..029f324 100644
--- a/docs/components/fconf/index.rst
+++ b/docs/components/fconf/index.rst
@@ -146,3 +146,4 @@
fconf_properties
amu-bindings
+ mpmm-bindings
diff --git a/docs/components/fconf/mpmm-bindings.rst b/docs/components/fconf/mpmm-bindings.rst
new file mode 100644
index 0000000..d3cc857
--- /dev/null
+++ b/docs/components/fconf/mpmm-bindings.rst
@@ -0,0 +1,48 @@
+Maximum Power Mitigation Mechanism (MPMM) Bindings
+==================================================
+
+|MPMM| support cannot be determined at runtime by the firmware. Instead, these
+DTB bindings allow the platform to communicate per-core support for |MPMM| via
+the ``HW_CONFIG`` device tree blob.
+
+Bindings
+^^^^^^^^
+
+.. contents::
+ :local:
+
+``/cpus/cpus/cpu*`` node properties
+"""""""""""""""""""""""""""""""""""
+
+The ``cpu`` node has been augmented to allow the platform to indicate support
+for |MPMM| on a given core.
+
++-------------------+-------+-------------+------------------------------------+
+| Property name | Usage | Value type | Description |
++===================+=======+=============+====================================+
+| ``supports-mpmm`` | O | ``<empty>`` | If present, indicates that |MPMM| |
+| | | | is available on this core. |
++-------------------+-------+-------------+------------------------------------+
+
+Example
+^^^^^^^
+
+An example system offering two cores, one with support for |MPMM| and one
+without, can be described as follows:
+
+.. code-block::
+
+ cpus {
+ #address-cells = <2>;
+ #size-cells = <0>;
+
+ cpu0@00000 {
+ ...
+
+ supports-mpmm;
+ };
+
+ cpu1@00100 {
+ ...
+ };
+ }