From be58c81aff4cd4c0ccf43dbd7998da4a6a08c03b Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 21 Apr 2024 19:43:51 +0200 Subject: Adding upstream version 2.10.0+dfsg. Signed-off-by: Daniel Baumann --- docs/components/fconf/amu-bindings.rst | 142 +++++++++++++++++++++++++++++++++ 1 file changed, 142 insertions(+) create mode 100644 docs/components/fconf/amu-bindings.rst (limited to 'docs/components/fconf/amu-bindings.rst') diff --git a/docs/components/fconf/amu-bindings.rst b/docs/components/fconf/amu-bindings.rst new file mode 100644 index 0000000..047f75e --- /dev/null +++ b/docs/components/fconf/amu-bindings.rst @@ -0,0 +1,142 @@ +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 | ```` | 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 | ```` | Value shall be 1. Specifies that | +| | | | the ``reg`` property array of | +| | | | children of this node uses a | +| | | | single cell. | ++--------------------+-------+------------+------------------------------------+ +| ``#size-cells`` | R | ```` | 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 | ```` | 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``. -- cgit v1.2.3