GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

2026-09-06 03:52:57 +08:00
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+Activity Monitor Unit (AMU) Bindings
+====================================
+
+To support platform-defined Activity Monitor Unit (|AMU|) auxiliary counters
+through FCONF, the ``HW_CONFIG`` device tree accepts several |AMU|-specific
+nodes and properties.
+
+Bindings
+^^^^^^^^
+
+.. contents::
+    :local:
+
+``/cpus/cpus/cpu*`` node properties
+"""""""""""""""""""""""""""""""""""
+
+The ``cpu`` node has been augmented to support a handle to an associated |AMU|
+view, which should describe the counters offered by the core.
+
+---------------+-------+---------------+-------------------------------------+
+| Property name | Usage | Value type    | Description                         |
+===============+=======+===============+=====================================+
+| ``amu``       | O     | ``<phandle>`` | If present, indicates that an |AMU| |
+|               |       |               | is available and its counters are   |
+|               |       |               | described by the node provided.     |
+---------------+-------+---------------+-------------------------------------+
+
+``/cpus/amus`` node properties
+""""""""""""""""""""""""""""""
+
+The ``amus`` node describes the |AMUs| implemented by the cores in the system.
+This node does not have any properties.
+
+``/cpus/amus/amu*`` node properties
+"""""""""""""""""""""""""""""""""""
+
+An ``amu`` node describes the layout and meaning of the auxiliary counter
+registers of one or more |AMUs|, and may be shared by multiple cores.
+
+--------------------+-------+------------+------------------------------------+
+| Property name      | Usage | Value type | Description                        |
+====================+=======+============+====================================+
+| ``#address-cells`` | R     | ``<u32>``  | Value shall be 1. Specifies that   |
+|                    |       |            | the ``reg`` property array of      |
+|                    |       |            | children of this node uses a       |
+|                    |       |            | single cell.                       |
+--------------------+-------+------------+------------------------------------+
+| ``#size-cells``    | R     | ``<u32>``  | Value shall be 0. Specifies that   |
+|                    |       |            | no size is required in the ``reg`` |
+|                    |       |            | property in children of this node. |
+--------------------+-------+------------+------------------------------------+
+
+``/cpus/amus/amu*/counter*`` node properties
+""""""""""""""""""""""""""""""""""""""""""""
+
+A ``counter`` node describes an auxiliary counter belonging to the parent |AMU|
+view.
+
+-------------------+-------+-------------+------------------------------------+
+| Property name     | Usage | Value type  | Description                        |
+===================+=======+=============+====================================+
+| ``reg``           | R     | array       | Represents the counter register    |
+|                   |       |             | index, and must be a single cell.  |
+-------------------+-------+-------------+------------------------------------+
+| ``enable-at-el3`` | O     | ``<empty>`` | The presence of this property      |
+|                   |       |             | indicates that this counter should |
+|                   |       |             | be enabled prior to EL3 exit.      |
+-------------------+-------+-------------+------------------------------------+
+
+Example
+^^^^^^^
+
+An example system offering four cores made up of two clusters, where the cores
+of each cluster share different |AMUs|, may use something like the following:
+
+.. code-block::
+
+    cpus {
+        #address-cells = <2>;
+        #size-cells = <0>;
+
+        amus {
+            amu0: amu-0 {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                counterX: counter@0 {
+                    reg = <0>;
+
+                    enable-at-el3;
+                };
+
+                counterY: counter@1 {
+                    reg = <1>;
+
+                    enable-at-el3;
+                };
+            };
+
+            amu1: amu-1 {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                counterZ: counter@0 {
+                    reg = <0>;
+
+                    enable-at-el3;
+                };
+            };
+        };
+
+        cpu0@00000 {
+            ...
+
+            amu = <&amu0>;
+        };
+
+        cpu1@00100 {
+            ...
+
+            amu = <&amu0>;
+        };
+
+        cpu2@10000 {
+            ...
+
+            amu = <&amu1>;
+        };
+
+        cpu3@10100 {
+            ...
+
+            amu = <&amu1>;
+        };
+    }
+
+In this situation, ``cpu0`` and ``cpu1`` (the two cores in the first cluster),
+share the view of their AMUs defined by ``amu0``. Likewise, ``cpu2`` and
+``cpu3`` (the two cores in the second cluster), share the view of their |AMUs|
+defined by ``amu1``. This will cause ``counterX`` and ``counterY`` to be enabled
+for both ``cpu0`` and ``cpu1``, and ``counterZ`` to be enabled for both ``cpu2``
+and ``cpu3``.