SW427193 / HW461448: Enable memory controller wat

Change-Id: I2fc4cf0dda43d4eba543024605c8f358e22e1bae
CQ:SW427193
CQ:HW461448
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/65476
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: HWSV CI <hwsv-ci+hostboot@us.ibm.com>
Reviewed-by: Adam S. Hale <adam.samuel.hale@ibm.com>
Tested-by: PPE CI <ppe-ci+hostboot@us.ibm.com>
Tested-by: Hostboot CI <hostboot-ci+hostboot@us.ibm.com>
Reviewed-by: Thi N. Tran <thi@us.ibm.com>
Reviewed-by: Joseph J. McGill <jmcgill@us.ibm.com>
Reviewed-by: Jennifer A. Stofer <stofer@us.ibm.com>
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/65508
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Sachin Gupta <sgupta2m@in.ibm.com>

src/import/chips/p9/procedures/xml/attribute_info/chip_ec_attributes.xml

@@ -7841,6 +7841,27 @@
     </chipEcFeature>
   </attribute>
   <!-- ******************************************************************** -->
+  <attribute>
+    <id>ATTR_CHIP_EC_FEATURE_HW461448</id>
+    <targetType>TARGET_TYPE_PROC_CHIP</targetType>
+    <description>
+        Enable MC WAT to hold off incoming commands to the memory controller after
+        a certain fullness level. Currently configured to hold off for 75 counts
+        after reaching 16 entries in the write buffers. This will allow existing
+        entries in queue to make forward progress before commiting more into the
+        queues.
+    </description>
+    <chipEcFeature>
+      <chip>
+        <name>ENUM_ATTR_NAME_CUMULUS</name>
+        <ec>
+          <value>0x10</value>
+          <test>GREATER_THAN_OR_EQUAL</test>
+        </ec>
+      </chip>
+    </chipEcFeature>
+  </attribute>
+  <!-- ******************************************************************** -->
   <attribute>
     <id>ATTR_CHIP_EC_FEATURE_SYNC_SS_PLL_SPREAD</id>
     <targetType>TARGET_TYPE_PROC_CHIP</targetType>