1*54fd6939SJiyong ParkMaximum Power Mitigation Mechanism (MPMM) 2*54fd6939SJiyong Park^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 3*54fd6939SJiyong Park 4*54fd6939SJiyong Park|MPMM| is an optional microarchitectural power management mechanism supported by 5*54fd6939SJiyong Parksome Arm Armv9-A cores, beginning with the Cortex-X2, Cortex-A710 and 6*54fd6939SJiyong ParkCortex-A510 cores. This mechanism detects and limits high-activity events to 7*54fd6939SJiyong Parkassist in |SoC| processor power domain dynamic power budgeting and limit the 8*54fd6939SJiyong Parktriggering of whole-rail (i.e. clock chopping) responses to overcurrent 9*54fd6939SJiyong Parkconditions. 10*54fd6939SJiyong Park 11*54fd6939SJiyong Park|MPMM| is enabled on a per-core basis by the EL3 runtime firmware. The presence 12*54fd6939SJiyong Parkof |MPMM| cannot be determined at runtime by the firmware, and therefore the 13*54fd6939SJiyong Parkplatform must expose this information through one of two possible mechanisms: 14*54fd6939SJiyong Park 15*54fd6939SJiyong Park- |FCONF|, controlled by the ``ENABLE_MPMM_FCONF`` build option. 16*54fd6939SJiyong Park- A platform implementation of the ``plat_mpmm_topology`` function (the 17*54fd6939SJiyong Park default). 18*54fd6939SJiyong Park 19*54fd6939SJiyong ParkSee :ref:`Maximum Power Mitigation Mechanism (MPMM) Bindings` for documentation 20*54fd6939SJiyong Parkon the |FCONF| device tree bindings. 21*54fd6939SJiyong Park 22*54fd6939SJiyong Park.. warning:: 23*54fd6939SJiyong Park 24*54fd6939SJiyong Park |MPMM| exposes gear metrics through the auxiliary |AMU| counters. An 25*54fd6939SJiyong Park external power controller can use these metrics to budget SoC power by 26*54fd6939SJiyong Park limiting the number of cores that can execute higher-activity workloads or 27*54fd6939SJiyong Park switching to a different DVFS operating point. When this is the case, the 28*54fd6939SJiyong Park |AMU| counters that make up the |MPMM| gears must be enabled by the EL3 29*54fd6939SJiyong Park runtime firmware - please see :ref:`Activity Monitor Auxiliary Counters` for 30*54fd6939SJiyong Park documentation on enabling auxiliary |AMU| counters. 31