Updates to Isolator class interfaces

Change-Id: I9c7abeba489507de9f4a2a075a5c94d7fcf25247
Signed-off-by: Zane Shelley <zshelle@us.ibm.com>
diff --git a/src/hei_return_code.hpp b/src/hei_return_code.hpp
index cdb1700..ce32468 100644
--- a/src/hei_return_code.hpp
+++ b/src/hei_return_code.hpp
@@ -59,7 +59,17 @@
 };
 
 /** Function returned successfully. */
-static constexpr ReturnCode RC_SUCCESS = ReturnCode();
+static constexpr ReturnCode RC_SUCCESS                 = ReturnCode();
 
-}; // end namespace libhei
+/** The given Chip Data File is malformed or unsupported. */
+static constexpr ReturnCode RC_CHIP_DATA_INVALID       = ReturnCode(0x00000001);
+
+/** The given Chip Data File contains a chip type that has already been
+ *  initialized. */
+static constexpr ReturnCode RC_CHIP_DATA_INITIALIZED   = ReturnCode(0x00000002);
+
+/** The given chip type has not been initialized. */
+static constexpr ReturnCode RC_CHIP_DATA_MISSING       = ReturnCode(0x00000003);
+
+} // end namespace libhei