[Skiboot] [PATCH v4 7/8] skiboot: Add documentation for the Core IMC opal call

[Hemant Kumar]

Adds documentation for the opal_core_imc_counters_control() interface.
---
 doc/opal-api/opal-core-imc-counters.rst | 40 +++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 doc/opal-api/opal-core-imc-counters.rst

diff --git a/doc/opal-api/opal-core-imc-counters.rst b/doc/opal-api/opal-core-imc-counters.rst
new file mode 100644
index 0000000..59ee8fa
--- /dev/null
+++ b/doc/opal-api/opal-core-imc-counters.rst
@@ -0,0 +1,40 @@
+OPAL_CORE_IMC_COUNTERS_CONTROL
+==============================
+
+OPAL call interface for per-core IMC instrumentation support.
+Currently, the interface supports initializing, enabling and disabling
+the core IMC engine from the Host OS.
+
+The interface can be extended to include more modes and operations
+available in core IMC.
+
+Parameters
+----------
+``uint64_t operation``
+  3 operations are supported for now (include/opal-api.h) :
+  - OPAL_CORE_IMC_DISABLE -- disable or stop the counters
+  - OPAL_CORE_IMC_ENABLE -- enable/resume the counters
+  - OPAL_CORE_IMC_INIT -- Initialize and enable the counters.
+
+``uint64_t addr``
+  For OPAL_CORE_IMC_INIT, this parameter must have a non-zero value.
+  This value must be a per-core physical address.
+  For other operations, this value is undefined and must be zero.
+
+``uint64_t value_1``
+  - This parameter is undefined for now and must be zero.
+
+``uint64_t value_2``
+  - This parameter is undefined for now and must be zero.
+
+Returns
+-------
+OPAL_PARAMETER
+  In any one/some/all of the following cases :
+  - Unsupported ``operation``
+  - Wrong ``addr`` for the given ``operation``
+  - Non-zero ``value_1`` or ``value_2``
+OPAL_HARDWARE
+   If xscom_write fails.
+OPAL_SUCCESS
+   On successful execution of the ``operation``.
-- 
2.7.4