xref: /rk3399_ARM-atf/docs/components/mpmm.rst (revision 2e0354f58834219c65b1d44447b8510f3983a5ba)
1Maximum Power Mitigation Mechanism (MPMM)
2^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
3
4|MPMM| is an optional microarchitectural power management mechanism supported by
5some Arm Armv9-A cores, beginning with the Cortex-X2, Cortex-A710 and
6Cortex-A510 cores. This mechanism detects and limits high-activity events to
7assist in |SoC| processor power domain dynamic power budgeting and limit the
8triggering of whole-rail (i.e. clock chopping) responses to overcurrent
9conditions.
10
11|MPMM| is enabled on a per-core basis by the EL3 runtime firmware.
12
13.. warning::
14
15    |MPMM| exposes gear metrics through the auxiliary |AMU| counters. An
16    external power controller can use these metrics to budget SoC power by
17    limiting the number of cores that can execute higher-activity workloads or
18    switching to a different DVFS operating point. When this is the case, the
19    |AMU| counters that make up the |MPMM| gears must be enabled by the EL3
20    runtime firmware - please see :ref:`Activity Monitor Auxiliary Counters` for
21    documentation on enabling auxiliary |AMU| counters.
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