Add MRW XML requirements document.

This document lists the MRW data required by the
OpenBMC code.  This allows the MRW owner to know what
to put in.

Change-Id: I05b41a0c4f7519d6d7b358a54b0ad454b6863924
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/docs/mrw-xml-requirements.md b/docs/mrw-xml-requirements.md
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+# OpenBMC MRW Requirements
+
+This document describes the data requirements that OpenBMC has on the machine
+readable workbook XML generated by [Serverwiz2](https://www.github.com/open-power/serverwiz).
+The requirements in this document are broken up by the OpenBMC functions that
+use them.
+
+If a particular OpenBMC implementation doesn't use a certain function,
+then that MRW data isn't required.
+
+## System Inventory
+
+The system inventory can be generated from the MRW XML.  The inventory
+typically contains all FRUs (field replaceable units), along with a few
+non-FRU entities, like the BMC chip and processor cores.
+
+To specify a target in the MRW should be in the inventory:
+
+* Set the FRU\_NAME attribute of that target.
+
+**Note**: The BMC and cores will be automatically added without the need to
+set FRU\_NAME.