Establish Base Support For Sending Mailbox Messages Across XBUS/ABUS

This commit establishes base support for Secure Node Communications.
It creates a new device driver to operate the XBUS and ABUS Link
Mailboxes and adds base support for using these device drivers to
send and receive messages.  It also adds a test to perform a 2-chip
XBUS Link Mailbox operation.

Change-Id: I19510888c0922e5bb857cffc9426399e79e113ba
RTC:191008
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/58376
Reviewed-by: Nicholas E. Bofferding <bofferdn@us.ibm.com>
Reviewed-by: ILYA SMIRNOV <ismirno@us.ibm.com>
Reviewed-by: Marshall J. Wilks <mjwilks@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: William G. Hoffa <wghoffa@us.ibm.com>

14 files changed, 1666 insertions, 4 deletions

diff --git a/src/include/usr/devicefw/userif.H b/src/include/usr/devicefw/userif.H
index 286deabb1..4df37c8a8 100644
--- a/src/include/usr/devicefw/userif.H
+++ b/src/include/usr/devicefw/userif.H
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2011,2017                        */
+/* Contributors Listed Below - COPYRIGHT 2011,2018                        */
 /* [+] Google Inc.                                                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
@@ -68,6 +68,7 @@ namespace DeviceFW
         AHB_SIO,
         DVPD,      // Direct access memory VPD
         MEMD_VPD,
+        NODECOMM,
 
         LAST_ACCESS_TYPE,
     };
@@ -371,6 +372,26 @@ namespace DeviceFW
             static_cast<uint64_t>(( i_gpio_portAddr ))
 
     /**
+     * Construct the device addressing parameters for the Node Comm device ops.
+     * @param[in] i_mode        Either ABUS or XBUS mode - see node_comm_modes_t
+     *                          enum defined in nodecommif.H.
+     * @param[in] i_link_id     The Link Id used for routing the message.
+     *                          MAX values for ABUS and XBUS mode are defined in
+     *                          nodecommif.H.
+     * @param[in] i_mailbox_id  Tha Mailbox Id used for routing the message.
+     *                          NOTE: Only "0" or "1" are supported.
+     *
+     * @note      This interface only supports the reading and writing of
+     *            8 bytes (64 bits) per operation. Anything else will fail.
+     */
+    #define DEVICE_NODECOMM_ADDRESS( i_mode, i_link_id, i_mailbox_id )  \
+        DeviceFW::NODECOMM,\
+            static_cast<uint64_t>(( i_mode )),\
+            static_cast<uint64_t>(( i_link_id )),\
+            static_cast<uint64_t>(( i_mailbox_id ))
+
+
+    /**
      *  @brief Perform a hardware read operation.
      *
      *  @param[in]     i_target     Device target to operate on.
diff --git a/src/include/usr/isteps/istep09list.H b/src/include/usr/isteps/istep09list.H
index 4adcc0810..6917499af 100644
--- a/src/include/usr/isteps/istep09list.H
+++ b/src/include/usr/isteps/istep09list.H
@@ -232,6 +232,7 @@ const DepModInfo  g_istep09Dependancies = {
         DEP_LIB(libnestmemutils.so),
         DEP_LIB(libfab_iovalid.so),
         DEP_LIB(libimageprocs.so),
+        DEP_LIB(libnode_comm.so),
         NULL
     }
 };
diff --git a/src/include/usr/secureboot/nodecommif.H b/src/include/usr/secureboot/nodecommif.H
new file mode 100644
index 000000000..6787c99ea
--- /dev/null
+++ b/src/include/usr/secureboot/nodecommif.H
@@ -0,0 +1,76 @@
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: src/include/usr/secureboot/nodecommif.H $                     */
+/*                                                                        */
+/* OpenPOWER HostBoot Project                                             */
+/*                                                                        */
+/* Contributors Listed Below - COPYRIGHT 2018                             */
+/* [+] International Business Machines Corp.                              */
+/*                                                                        */
+/*                                                                        */
+/* Licensed under the Apache License, Version 2.0 (the "License");        */
+/* you may not use this file except in compliance with the License.       */
+/* You may obtain a copy of the License at                                */
+/*                                                                        */
+/*     http://www.apache.org/licenses/LICENSE-2.0                         */
+/*                                                                        */
+/* Unless required by applicable law or agreed to in writing, software    */
+/* distributed under the License is distributed on an "AS IS" BASIS,      */
+/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or        */
+/* implied. See the License for the specific language governing           */
+/* permissions and limitations under the License.                         */
+/*                                                                        */
+/* IBM_PROLOG_END_TAG                                                     */
+#ifndef __NODECOMMIF_H
+#define __NODECOMMIF_H
+
+#include <initservice/mboxRegs.H>
+#include <config.h>
+#include <errl/errlentry.H>
+
+namespace SECUREBOOT
+{
+
+namespace NODECOMM
+{
+
+/*
+ * @brief The Node Communications Device Driver can *only* support ABUS or
+ *        XBUS operations.  This enum will be passed in by callers and it
+ *        will be verified that only the XBUS or ABUS values were passed in.
+ */
+enum node_comm_modes_t
+{
+    NCDD_MODE_XBUS    = 0,
+    NCDD_MODE_ABUS    = 1,
+
+    // INVALID value and will be used for checks and asserts, like:
+    // assert(mode < NCDD_MODE_INVALID)
+    NCDD_MODE_INVALID = 2,
+};
+
+enum node_comm_link_mbox_info_t
+{
+    NCDD_MAX_ABUS_LINK_ID  = 7,
+    NCDD_MAX_XBUS_LINK_ID  = 5,
+    NCDD_MAX_MBOX_ID       = 1,
+    NCDD_INVALID_LINK_MBOX = 0xFF,
+};
+
+/**
+ *  @brief Execute a single transmission from one proc to another
+ *         over the XBUS Link Mailbox facility
+ *
+ *  @return errHndl_t Error log handle indicating success or failure
+ *  @retval nullptr  Test completed successfully
+ *  @retval !nullptr Error log providing failure details
+ */
+errlHndl_t nodeCommXbus2ProcTest(void);
+
+} // End NODECOMM namespace
+
+} // End SECUREBOOT namespace
+
+#endif // End __NODECOMMIF_H
+
diff --git a/src/include/usr/secureboot/secure_reasoncodes.H b/src/include/usr/secureboot/secure_reasoncodes.H
index 5dcb4bf5a..f692d4753 100644
--- a/src/include/usr/secureboot/secure_reasoncodes.H
+++ b/src/include/usr/secureboot/secure_reasoncodes.H
@@ -48,6 +48,13 @@ namespace SECUREBOOT
         MOD_SECURE_GET_ALL_SEC_REGS     = 0x0E,
         MOD_SECURE_LOAD_HEADER          = 0x0F,
         MOD_SECURE_VALIDATE_ECID_COUNT  = 0x10,
+
+        // Use 0x20-0x2F range for Node Communications
+        MOD_NCDD_CHECK_FOR_ERRORS       = 0x20,
+        MOD_NCDD_WAIT_FOR_CMD_COMP      = 0x21,
+        MOD_NC_XBUS_TEST                = 0x22,
+        MOD_NC_MAP_ATTN                 = 0x23,
+        MOD_NCDD_PERFORM_OP             = 0x24,
    };
 
     enum SECUREReasonCode
@@ -72,6 +79,15 @@ namespace SECUREBOOT
         RC_DEVICE_READ_ERR              = SECURE_COMP_ID | 0x11,
         RC_INVALID_BASE_HEADER          = SECURE_COMP_ID | 0x12,
         RC_INVALID_ECID_COUNT           = SECURE_COMP_ID | 0x13,
+
+        // Use 0x20-0x2F range for Node Communications
+        RC_NCDD_HW_ERROR_FOUND          = SECURE_COMP_ID | 0x20,
+        RC_NCDD_CMD_COMP_TIMEOUT        = SECURE_COMP_ID | 0x21,
+        RC_NC_DATA_MISCOMPARE           = SECURE_COMP_ID | 0x22,
+        RC_NC_NO_ATTN_FOUND             = SECURE_COMP_ID | 0x23,
+        RC_NC_TOO_MANY_ATTNS_FOUND      = SECURE_COMP_ID | 0x24,
+        RC_NCDD_INVALID_ARGS            = SECURE_COMP_ID | 0x25,
+
         // Reason codes 0xA0 - 0xEF reserved for trustedboot_reasoncodes.H
     };
 
diff --git a/src/makefile b/src/makefile
index e25729575..f2b570dcc 100644
--- a/src/makefile
+++ b/src/makefile
@@ -208,6 +208,7 @@ EXTENDED_MODULES += nestmemutils
 EXTENDED_MODULES += fab_iovalid
 EXTENDED_MODULES += isteps_nest
 EXTENDED_MODULES += isteps_io
+EXTENDED_MODULES += node_comm
 
 #***************************************
 # Working test modules
diff --git a/src/usr/initservice/extinitsvc/extinitsvctasks.H b/src/usr/initservice/extinitsvc/extinitsvctasks.H
index 49c76400a..04798d791 100644
--- a/src/usr/initservice/extinitsvc/extinitsvctasks.H
+++ b/src/usr/initservice/extinitsvc/extinitsvctasks.H
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2011,2017                        */
+/* Contributors Listed Below - COPYRIGHT 2011,2018                        */
 /* [+] Google Inc.                                                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
@@ -368,6 +368,18 @@ const TaskInfo g_exttaskinfolist[]   =   {
 #endif
 
         /**
+         * @brief   Node Communications Device Driver library
+         */
+        {
+            "libnode_comm.so" ,                 // taskname
+            NULL,                               // no pointer to fn
+            {
+                INIT_TASK,                      // task type
+                EXT_IMAGE,                      // Extended Module
+            }
+        },
+
+        /**
          * @brief   Common istep functions
          *
          *
diff --git a/src/usr/isteps/istep09/call_proc_smp_link_layer.C b/src/usr/isteps/istep09/call_proc_smp_link_layer.C
index 07d970636..06b7ac613 100644
--- a/src/usr/isteps/istep09/call_proc_smp_link_layer.C
+++ b/src/usr/isteps/istep09/call_proc_smp_link_layer.C
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2015,2016                        */
+/* Contributors Listed Below - COPYRIGHT 2015,2018                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
 /*                                                                        */
@@ -51,6 +51,7 @@
 #include    <hwas/common/hwasCommon.H>
 
 #include    <sbe/sbeif.H>
+#include    <secureboot/nodecommif.H>
 
 //  targeting support
 #include    <targeting/common/commontargeting.H>
@@ -80,10 +81,14 @@ void*   call_proc_smp_link_layer( void    *io_pArgs )
 {
     errlHndl_t  l_errl  =   NULL;
     IStepError  l_StepError;
+    bool l_run_xbus_test = true;
 
     TRACFCOMP( ISTEPS_TRACE::g_trac_isteps_trace,
                "call_proc_smp_link_layer entry" );
 
+    do
+    {
+
     //
     //  get a list of all the procs in the system
     //
@@ -111,9 +116,26 @@ void*   call_proc_smp_link_layer( void    *io_pArgs )
                      TARGETING::get_huid(l_cpu_target) );
             l_StepError.addErrorDetails(l_errl);
             errlCommit(l_errl, HWPF_COMP_ID);
+            l_run_xbus_test = false;
         }
     }
 
+    // Test sending messages between procs via XBUS mailbox
+    if (l_run_xbus_test)
+    {
+        l_errl = SECUREBOOT::NODECOMM::nodeCommXbus2ProcTest();
+        if(l_errl)
+        {
+            TRACFCOMP( ISTEPS_TRACE::g_trac_isteps_trace,ERR_MRK
+                       "call_proc_smp_link_layer> "
+                       "nodeCommXbus2ProcTest Failed!");
+            l_StepError.addErrorDetails(l_errl);
+            errlCommit(l_errl, HWPF_COMP_ID);
+        }
+    }
+
+    } while(0);
+
     TRACFCOMP( ISTEPS_TRACE::g_trac_isteps_trace,
                "call_proc_smp_link_layer exit" );
 
diff --git a/src/usr/secureboot/makefile b/src/usr/secureboot/makefile
index 5ac61aba7..c9a6a91b8 100644
--- a/src/usr/secureboot/makefile
+++ b/src/usr/secureboot/makefile
@@ -5,7 +5,7 @@
 #
 # OpenPOWER HostBoot Project
 #
-# Contributors Listed Below - COPYRIGHT 2013,2016
+# Contributors Listed Below - COPYRIGHT 2013,2018
 # [+] International Business Machines Corp.
 #
 #
@@ -28,5 +28,6 @@ SUBDIRS += base.d
 SUBDIRS += ext.d
 SUBDIRS += trusted.d
 SUBDIRS += runtime.d
+SUBDIRS += node_comm.d
 
 include ${ROOTPATH}/config.mk
diff --git a/src/usr/secureboot/node_comm/makefile b/src/usr/secureboot/node_comm/makefile
new file mode 100644
index 000000000..d41851e71
--- /dev/null
+++ b/src/usr/secureboot/node_comm/makefile
@@ -0,0 +1,38 @@
+# IBM_PROLOG_BEGIN_TAG
+# This is an automatically generated prolog.
+#
+# $Source: src/usr/secureboot/node_comm/makefile $
+#
+# OpenPOWER HostBoot Project
+#
+# Contributors Listed Below - COPYRIGHT 2018
+# [+] International Business Machines Corp.
+#
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied. See the License for the specific language governing
+# permissions and limitations under the License.
+#
+# IBM_PROLOG_END_TAG
+ROOTPATH = ../../../..
+MODULE = node_comm
+include ../common/common.mk
+#SUBDIRS += test.d
+
+OBJS += node_comm_dd.o
+OBJS += node_comm_test.o
+OBJS += node_comm.o
+
+VPATH += $(ROOTPATH)/src/usr/targeting/common
+EXTRAINCDIR += $(ROOTPATH)/src/include/usr
+
+CFLAGS += -iquote ../
+include ${ROOTPATH}/config.mk
diff --git a/src/usr/secureboot/node_comm/node_comm.C b/src/usr/secureboot/node_comm/node_comm.C
new file mode 100644
index 000000000..b47f78273
--- /dev/null
+++ b/src/usr/secureboot/node_comm/node_comm.C
@@ -0,0 +1,200 @@
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: src/usr/secureboot/node_comm/node_comm.C $                    */
+/*                                                                        */
+/* OpenPOWER HostBoot Project                                             */
+/*                                                                        */
+/* Contributors Listed Below - COPYRIGHT 2018                             */
+/* [+] International Business Machines Corp.                              */
+/*                                                                        */
+/*                                                                        */
+/* Licensed under the Apache License, Version 2.0 (the "License");        */
+/* you may not use this file except in compliance with the License.       */
+/* You may obtain a copy of the License at                                */
+/*                                                                        */
+/*     http://www.apache.org/licenses/LICENSE-2.0                         */
+/*                                                                        */
+/* Unless required by applicable law or agreed to in writing, software    */
+/* distributed under the License is distributed on an "AS IS" BASIS,      */
+/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or        */
+/* implied. See the License for the specific language governing           */
+/* permissions and limitations under the License.                         */
+/*                                                                        */
+/* IBM_PROLOG_END_TAG                                                     */
+/**
+ * @file node_comm.C
+ *
+ * @brief Implementation of the Secure Node Communications Functions
+ *
+ */
+
+// ----------------------------------------------
+// Includes
+// ----------------------------------------------
+#include <string.h>
+#include <errl/errlentry.H>
+#include <errl/errlmanager.H>
+#include <errl/errludtarget.H>
+#include <targeting/common/targetservice.H>
+#include <devicefw/userif.H>
+#include <devicefw/driverif.H>
+#include <secureboot/secure_reasoncodes.H>
+#include <secureboot/nodecommif.H>
+#include <targeting/common/commontargeting.H>
+#include <targeting/common/utilFilter.H>
+
+#include "node_comm.H"
+
+
+using   namespace   TARGETING;
+
+namespace SECUREBOOT
+{
+
+namespace NODECOMM
+{
+
+/**
+ *  @brief Map Attention Bits in FIR Register to specific Link Mailbox
+ */
+errlHndl_t nodeCommMapAttn(TARGETING::Target* i_pProc,
+                           const node_comm_modes_t i_mode,
+                           bool & o_attn_found,
+                           uint64_t & o_linkId,
+                           uint64_t & o_mboxId)
+{
+    errlHndl_t err = nullptr;
+    uint64_t fir_data = 0x0;
+    uint64_t fir_data_with_mask = 0x0;
+    o_attn_found = false;
+
+    assert(i_mode < NCDD_MODE_INVALID,"nodeCommMapAttn: Invalid mode: %d",
+           i_mode);
+
+    const uint64_t fir_mask = (i_mode == NCDD_MODE_ABUS)
+                              ? NCDD_ABUS_FIR_ATTN_MASK
+                              : NCDD_XBUS_FIR_ATTN_MASK;
+
+    const uint64_t fir_addr = (i_mode == NCDD_MODE_ABUS)
+                              ? NCDD_REG_FIR + NCDD_ABUS_REG_OFFSET
+                              : NCDD_REG_FIR;
+
+    const size_t expSize = sizeof(fir_data);
+
+    TRACFCOMP(g_trac_nc,ENTER_MRK
+              "nodeCommMapAttn: tgt=0x%X, mode=%s, fir_addr=0x%.16llX",
+              get_huid(i_pProc),
+              (i_mode == NCDD_MODE_ABUS)
+                ? NCDD_ABUS_STRING : NCDD_XBUS_STRING,
+              fir_addr);
+
+
+    do
+    {
+    // Read the FIR reg
+    auto reqSize = expSize;
+    err = DeviceFW::deviceRead(i_pProc,
+                               &fir_data,
+                               reqSize,
+                               DEVICE_SCOM_ADDRESS(fir_addr));
+
+    if(err)
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"nodeCommMapAttn Read Fail! (%s): "
+                  " tgt=0x%X, reg_addr=0x%.16llX, data=0x%.16llX "
+                  TRACE_ERR_FMT,
+                  (i_mode == NCDD_MODE_ABUS)
+                    ? NCDD_ABUS_STRING : NCDD_XBUS_STRING,
+                  TARGETING::get_huid(i_pProc),
+                  fir_addr, fir_data,
+                  TRACE_ERR_ARGS(err));
+        break;
+    }
+    assert(reqSize==expSize,"nodeCommMapAttn: SCOM deviceRead didn't return expected data size of %d (it was %d)",
+           expSize,reqSize);
+
+    // Map Attention bits in the FIR
+    fir_data_with_mask = fir_data & fir_mask;
+    const int bit_count = __builtin_popcount(fir_data_with_mask);
+    TRACUCOMP(g_trac_nc,"nodeCommMapAttn: FIR data = 0x%.16llX, "
+              "mask=0x%.16llX, data+mask=0x%.16llX, count=%d",
+              fir_data, fir_mask, fir_data_with_mask, bit_count);
+
+    if (bit_count == 0)
+    {
+        TRACFCOMP(g_trac_nc,INFO_MRK"nodeCommMapAttn: no attentions found");
+        break;
+    }
+    else if (bit_count > 1)
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"nodeCommMapAttn: "
+                  "Too many attentions found (%d) in fir: data=0x%.16llX, "
+                  "data+mask=0x%.16llX, fir_addr=0x%.16llX",
+                  bit_count, fir_data, fir_data_with_mask, fir_addr);
+
+        /*@
+         * @errortype
+         * @reasoncode       RC_NC_TOO_MANY_ATTNS_FOUND
+         * @moduleid         MOD_NC_MAP_ATTN
+         * @userdata1        Raw FIR Data
+         * @userdata2[0:31]  Number of Attentions found
+         * @userdata2[32:63] Target HUID FIR was read from
+         * @devdesc          Too many attentions were found in
+         *                   the Node Comm FIR Register
+         * @custdesc         Secure Boot failure
+         */
+        err = new ERRORLOG::ErrlEntry( ERRORLOG::ERRL_SEV_UNRECOVERABLE,
+                                       MOD_NC_MAP_ATTN,
+                                       RC_NC_TOO_MANY_ATTNS_FOUND,
+                                       fir_data,
+                                       TWO_UINT32_TO_UINT64(
+                                         bit_count,
+                                         get_huid(i_pProc)));
+
+        // Likely HB code failed to do the procedure correctly
+        err->addProcedureCallout(HWAS::EPUB_PRC_HB_CODE,
+                                 HWAS::SRCI_PRIORITY_HIGH);
+
+        // Or unlikely an issue with Processor or its bus
+        err->addHwCallout( i_pProc,
+                           HWAS::SRCI_PRIORITY_LOW,
+                           HWAS::NO_DECONFIG,
+                           HWAS::GARD_NULL );
+
+        err->collectTrace(SECURE_COMP_NAME);
+        err->collectTrace(NODECOMM_TRACE_NAME);
+
+        break;
+    }
+
+    int bit = 0;
+    const int possible_attn_bits = __builtin_popcount(fir_mask);
+    for ( ; bit < possible_attn_bits ; ++bit)
+    {
+        // Start at first bit and shift right to find an attention
+        if ( fir_data & (NCDD_START_OF_ATTN_BITS >> bit))
+        {
+            o_attn_found = true;
+            o_linkId = (bit / 2);
+            o_mboxId = (bit % 2);
+            break;
+        }
+    }
+
+    } while( 0 );
+
+    TRACFCOMP(g_trac_nc,EXIT_MRK"nodeCommMapAttn: tgt=0x%X: "
+              "o_attn_found=%d, o_linkId=%d, mboxId=%d, "
+              TRACE_ERR_FMT,
+              get_huid(i_pProc), o_attn_found, o_linkId, o_mboxId,
+              TRACE_ERR_ARGS(err));
+
+    return err;
+
+} // end of nodeCommMapAttn
+
+} // End NODECOMM namespace
+
+} // End SECUREBOOT namespace
+
diff --git a/src/usr/secureboot/node_comm/node_comm.H b/src/usr/secureboot/node_comm/node_comm.H
new file mode 100644
index 000000000..60a6dcae7
--- /dev/null
+++ b/src/usr/secureboot/node_comm/node_comm.H
@@ -0,0 +1,162 @@
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: src/usr/secureboot/node_comm/node_comm.H $                    */
+/*                                                                        */
+/* OpenPOWER HostBoot Project                                             */
+/*                                                                        */
+/* Contributors Listed Below - COPYRIGHT 2018                             */
+/* [+] International Business Machines Corp.                              */
+/*                                                                        */
+/*                                                                        */
+/* Licensed under the Apache License, Version 2.0 (the "License");        */
+/* you may not use this file except in compliance with the License.       */
+/* You may obtain a copy of the License at                                */
+/*                                                                        */
+/*     http://www.apache.org/licenses/LICENSE-2.0                         */
+/*                                                                        */
+/* Unless required by applicable law or agreed to in writing, software    */
+/* distributed under the License is distributed on an "AS IS" BASIS,      */
+/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or        */
+/* implied. See the License for the specific language governing           */
+/* permissions and limitations under the License.                         */
+/*                                                                        */
+/* IBM_PROLOG_END_TAG                                                     */
+#ifndef __NODE_COMM_H
+#define __NODE_COMM_H
+
+// ----------------------------------------------
+// Includes
+// ----------------------------------------------
+#include <config.h>
+#include <devicefw/userif.H>
+#include <trace/interface.H>
+#include <scom/centaurScomCache.H> // for TRACE_ERR_FMT, TRACE_ERR_ARGS
+#include <secureboot/nodecommif.H>
+// ----------------------------------------------
+// Defines
+// ----------------------------------------------
+#define NODECOMM_TRACE_NAME "NODECOMM"
+extern trace_desc_t* g_trac_nc;
+
+// Easy macro replace for unit testing - TRACD vs TRACF
+#define TRACUCOMP(args...) TRACFCOMP(args)
+
+namespace SECUREBOOT
+{
+
+namespace NODECOMM
+{
+
+/*****************************************************************************/
+/* Node Comm Registers Decription
+ *
+ * There is a set offset between the equivalent XBUS and ABUS registers such
+ * that in all cases ABUS Register Address = XBUS Register Address + 0x400.
+ * The offset of 0x400 will be applied if the operation is in ABUS mode.
+ */
+/*****************************************************************************/
+#define NCDD_ABUS_REG_OFFSET 0x400
+#define NCDD_ABUS_STRING "ABUS"
+#define NCDD_XBUS_STRING "XBUS"
+
+
+/*
+ * @brief Node Comm Registers - see above for description
+ */
+enum node_comm_registers_t : uint64_t
+{
+                             // XBUS values are default values
+                             // NCDD_ABUS_REG_OFFSET added if in ABUS mode
+    NCDD_REG_FIR          =  0x5013400,
+    NCDD_REG_CTRL         =  0x501342E,
+    NCDD_REG_DATA         =  0x501342F,
+
+   //MailBox Registers:
+   NCDD_REG_LINK_MBOX_00  =  0x5013430, //(secure)
+
+/* These registers are calculated by getLinkMboxReg() below
+   NCDD_REG_LINK_MBOX_01  =  0x5013431,
+   NCDD_REG_LINK_MBOX_10  =  0x5013432,
+   NCDD_REG_LINK_MBOX_11  =  0x5013433,
+   NCDD_REG_LINK_MBOX_20  =  0x5013434, //(secure)
+   NCDD_REG_LINK_MBOX_21  =  0x5013435,
+   NCDD_REG_LINK_MBOX_30  =  0x5013436,
+   NCDD_REG_LINK_MBOX_31  =  0x5013437,
+   NCDD_REG_LINK_MBOX_40  =  0x5013438, //(secure)
+   NCDD_REG_LINK_MBOX_41  =  0x5013439,
+   NCDD_REG_LINK_MBOX_50  =  0x501343A,
+   NCDD_REG_LINK_MBOX_51  =  0x501343B,
+
+   ABUS-Only: (but still use theoretical XBUS value and in NCDD_ABUS_REG_OFFSET)
+   NCDD_REG_LINK_MBOX_60  =  0x501343A, //(secure)
+   NCDD_REG_LINK_MBOX_61  =  0x501343B,
+   NCDD_REG_LINK_MBOX_70  =  0x501343A,
+   NCDD_REG_LINK_MBOX_71  =  0x501343B,
+*/
+};
+
+/**
+ *  @brief Calculate Link Mailbox Register Address based on mode (XBUS or ABUS)
+ *
+ *  @param[in] i_reg  - Register Base Address - see node_comm_registers_t
+ *  @param[in] i_mode - Indicates if the address is for a ABUS or XBUS operation
+ *
+ *  @return uint64_t - Calculated Link Mailbox Register Address
+ */
+inline uint64_t getLinkMboxRegAddr(uint64_t i_reg,
+                                   node_comm_modes_t i_mode)
+{
+    return (i_mode == NCDD_MODE_ABUS)
+              ? (i_reg + NCDD_ABUS_REG_OFFSET)
+              : i_reg;
+}
+
+/**
+ *  @brief Calculate Link Mailbox Base Register based on linkId and mboxId
+ *
+ *  @param[in] i_linkId - Link Id of the operation
+ *  @param[in] i_mboxId - Mailbox Id of the operation
+ *
+ *  @return uint64_t - Calculated Link Mailbox Register Base Address
+ *  @note   Returned value is Base/XBUS Address - see node_comm_registers_t
+ */
+inline uint64_t getLinkMboxReg(uint8_t i_linkId, uint8_t i_mboxId)
+{
+    return NCDD_REG_LINK_MBOX_00 + (2*i_linkId) + i_mboxId;
+}
+
+enum node_comm_fir_reg_helpers_t : uint64_t
+{
+    NCDD_ABUS_FIR_ATTN_MASK = 0x000000000FFFF000,
+    NCDD_XBUS_FIR_ATTN_MASK = 0x000000000FFF0000,
+    NCDD_START_OF_ATTN_BITS = 0x0000000008000000,
+};
+
+/**
+ *  @brief Map Attention Bits in XBUS/ABUS FIR Register to specific Link Mailbox
+ *
+ *  @param[in] i_pProc      Processor target to look for attentions on
+ *                          Can't be nullptr
+ *  @param[in] i_mode       Indicates to look for ABUS or XBUS attentions
+ *  @param[in] o_attn_found Returns true if attention was found; otherwise false
+ *  @param[in] o_linkId     Link Id attention was found on
+ *  @param[in] o_mboxId     Mbox Id attention was found on
+ *  @note - o_linkId and o_mboxId are only set/valid if o_attn_found is true
+ *
+ *  @return errlHndl_t Error log handle
+ *  @retval nullptr Operation was successful
+ *  @retval !nullptr Operation failed with valid error log
+ */
+errlHndl_t nodeCommMapAttn(TARGETING::Target* i_pProc,
+                           node_comm_modes_t i_mode,
+                           bool & o_attn_found,
+                           uint64_t & o_linkId,
+                           uint64_t & o_mboxId);
+
+} // end NODECOMM namespace
+
+} // end SECUREBOOT namespace
+
+#endif // End __NODE_COMM_H
+
diff --git a/src/usr/secureboot/node_comm/node_comm_dd.C b/src/usr/secureboot/node_comm/node_comm_dd.C
new file mode 100644
index 000000000..5029068fc
--- /dev/null
+++ b/src/usr/secureboot/node_comm/node_comm_dd.C
@@ -0,0 +1,596 @@
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: src/usr/secureboot/node_comm/node_comm_dd.C $                 */
+/*                                                                        */
+/* OpenPOWER HostBoot Project                                             */
+/*                                                                        */
+/* Contributors Listed Below - COPYRIGHT 2018                             */
+/* [+] International Business Machines Corp.                              */
+/*                                                                        */
+/*                                                                        */
+/* Licensed under the Apache License, Version 2.0 (the "License");        */
+/* you may not use this file except in compliance with the License.       */
+/* You may obtain a copy of the License at                                */
+/*                                                                        */
+/*     http://www.apache.org/licenses/LICENSE-2.0                         */
+/*                                                                        */
+/* Unless required by applicable law or agreed to in writing, software    */
+/* distributed under the License is distributed on an "AS IS" BASIS,      */
+/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or        */
+/* implied. See the License for the specific language governing           */
+/* permissions and limitations under the License.                         */
+/*                                                                        */
+/* IBM_PROLOG_END_TAG                                                     */
+/**
+ * @file node_comm_dd.C
+ *
+ * @brief Implementation of the Secure Node Communications device driver
+ *
+ */
+
+// ----------------------------------------------
+// Includes
+// ----------------------------------------------
+#include <string.h>
+#include <sys/time.h>
+#include <trace/interface.H>
+#include <errl/errlentry.H>
+#include <errl/errlmanager.H>
+#include <errl/errludtarget.H>
+#include <targeting/common/targetservice.H>
+#include <devicefw/userif.H>
+#include <devicefw/driverif.H>
+#include <secureboot/secure_reasoncodes.H>
+#include "node_comm_dd.H"
+#include "node_comm.H"
+
+// ----------------------------------------------
+// Globals
+// ----------------------------------------------
+
+// ----------------------------------------------
+// Trace definitions
+// ----------------------------------------------
+trace_desc_t* g_trac_nc = nullptr;
+TRAC_INIT( & g_trac_nc, NODECOMM_TRACE_NAME, KILOBYTE );
+
+
+// ----------------------------------------------
+// Defines
+// ----------------------------------------------
+// If the link(s) are up the operation should complete right away
+// so there will only be a short polling window
+#define NODE_COMM_POLL_DELAY_NS 1   // Sleep for 1ns per poll
+#define NODE_COMM_POLL_DELAY_TOTAL_NS 10 // Total time to poll
+
+
+using namespace TARGETING;
+
+namespace SECUREBOOT
+{
+
+namespace NODECOMM
+{
+
+// Register the generic I2C perform Op with the routing code for Procs.
+DEVICE_REGISTER_ROUTE( DeviceFW::WILDCARD,
+                       DeviceFW::NODECOMM,
+                       TARGETING::TYPE_PROC,
+                       nodeCommPerformOp );
+
+errlHndl_t nodeCommPerformOp( DeviceFW::OperationType i_opType,
+                         TARGETING::Target * i_target,
+                         void * io_buffer,
+                         size_t & io_buflen,
+                         int64_t i_accessType,
+                         va_list i_args )
+{
+    errlHndl_t err = nullptr;
+    node_comm_args_t node_comm_args;
+
+    uint64_t mode = va_arg( i_args, uint64_t );
+    node_comm_args.mode = static_cast<node_comm_modes_t>(mode);
+
+    uint64_t linkId = va_arg( i_args, uint64_t );
+    node_comm_args.linkId = static_cast<uint8_t>(linkId);
+
+    uint64_t mboxId = va_arg( i_args, uint64_t );
+    node_comm_args.mboxId = static_cast<uint8_t>(mboxId);
+
+    node_comm_args.data_ptr = reinterpret_cast<uint64_t*>(io_buffer);
+    node_comm_args.tgt = i_target;
+    node_comm_args.tgt_huid = TARGETING::get_huid(i_target);
+
+    do
+    {
+
+    // Check other input parameters
+    const auto max_linkId = (mode==NCDD_MODE_ABUS)
+                              ? NCDD_MAX_ABUS_LINK_ID
+                              : NCDD_MAX_XBUS_LINK_ID;
+
+    if (    (node_comm_args.mode >= NCDD_MODE_INVALID)
+         || (node_comm_args.linkId > max_linkId)
+         || (node_comm_args.mboxId > NCDD_MAX_MBOX_ID)
+         || (node_comm_args.data_ptr == nullptr)
+       )
+    {
+        TRACFCOMP( g_trac_nc,ERR_MRK"nodeCommPerformOp: Invalid Input Args!"
+                   " mode=%d, linkId=0x%X (max=0x%X), mboxId=0x%X, "
+                   " data_ptr=%p",
+                   node_comm_args.mode, node_comm_args.linkId,
+                   max_linkId, node_comm_args.mboxId,
+                   node_comm_args.data_ptr);
+
+        /*@
+         * @errortype
+         * @reasoncode       RC_NCDD_INVALID_ARGS
+         * @moduleid         MOD_NCDD_PERFORM_OP
+         * @userdata1[0:15]  BUS Mode Enum Value
+         * @userdata1[16:31] LinkId Value
+         * @userdata1[32:47] MAX possile LinkId Value based on Mode
+         * @userdata1[48:63] MailboxId Value
+         * @userdata2        Input Data Pointer
+         * @devdesc          Invalid Input Args for Node Comm DD call
+         * @custdesc         Secure Boot failure
+         */
+        err = new ERRORLOG::ErrlEntry( ERRORLOG::ERRL_SEV_UNRECOVERABLE,
+                                       MOD_NCDD_PERFORM_OP,
+                                       RC_NCDD_INVALID_ARGS,
+                                       FOUR_UINT16_TO_UINT64(
+                                         node_comm_args.mode,
+                                         node_comm_args.linkId,
+                                         max_linkId,
+                                         node_comm_args.mboxId),
+                                       reinterpret_cast<uint64_t>(
+                                         node_comm_args.data_ptr),
+                                       true /*Add HB SW Callout*/ );
+        break;
+    }
+
+    TRACUCOMP(g_trac_nc,ENTER_MRK"nodeCommPerformOp: %s: %s: "
+              "tgt=0x%X, LinkId=%d, MboxId=%d, data=0x%.16llX",
+              (node_comm_args.mode == NCDD_MODE_ABUS)
+              ? NCDD_ABUS_STRING : NCDD_XBUS_STRING,
+              ( i_opType == DeviceFW::READ ) ? "read" : "write",
+              node_comm_args.tgt_huid, node_comm_args.linkId,
+              node_comm_args.mboxId, (*node_comm_args.data_ptr));
+
+    // Mutex Lock
+    // @TODO RTC:191008 Support mutex
+
+    /***********************************************/
+    /* Node Comm Read                              */
+    /***********************************************/
+    if ( i_opType == DeviceFW::READ )
+    {
+        err = ncddRead( node_comm_args );
+    }
+
+    /***********************************************/
+    /* Node Comm Write                             */
+    /***********************************************/
+    else if( i_opType == DeviceFW::WRITE )
+    {
+        err = ncddWrite( node_comm_args);
+    }
+
+    // Handle Error from Operation (like a reset, if necessary)
+    if( err )
+    {
+
+        ncddHandleError( err,
+                         node_comm_args );
+        break;
+    }
+
+    }
+    while (0);
+
+    // Mutex Unlock
+    // @TODO RTC:191008 Support mutex
+
+    // If err, add trace and FFDC to log
+    if (err)
+    {
+        err->collectTrace(SECURE_COMP_NAME);
+        err->collectTrace(NODECOMM_TRACE_NAME);
+
+        // @TODO RTC:191008 Add FFDC - call to new UserDetails Section
+    }
+
+    TRACFCOMP (g_trac_nc, EXIT_MRK"nodeCommPerformOp: %s: %s: "
+               "tgt=0x%X, LinkId=%d, MboxId=%d, data=0x%.16llX. "
+               TRACE_ERR_FMT,
+               (node_comm_args.mode == NCDD_MODE_ABUS)
+                 ? NCDD_ABUS_STRING : NCDD_XBUS_STRING,
+               ( i_opType == DeviceFW::READ ) ? "read" : "write",
+               node_comm_args.tgt_huid,
+               node_comm_args.linkId, node_comm_args.mboxId,
+               (node_comm_args.data_ptr != nullptr)
+                ? (*node_comm_args.data_ptr) : 0,
+               TRACE_ERR_ARGS(err));
+
+    return err;
+} // end nodeCommPerformOp
+
+errlHndl_t ncddRead(node_comm_args_t & i_args)
+{
+    errlHndl_t err = nullptr;
+
+    do
+    {
+    // Determine correct Link Mailbox Register based on inputs
+    const uint64_t link_mbox_reg = getLinkMboxReg(i_args.linkId, i_args.mboxId);
+
+    // Read data from the correct LinkId/Mailbox Register
+    err = ncddRegisterOp( DeviceFW::READ,
+                          i_args.data_ptr,
+                          link_mbox_reg,
+                          i_args );
+
+    if(err)
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"ncddRead: SCOM deviceRead call "
+            "failed for Target HUID 0x%08X and address 0x%016llX. "
+            TRACE_ERR_FMT,
+            i_args.tgt_huid,
+            link_mbox_reg,
+            TRACE_ERR_ARGS(err));
+        break;
+    }
+
+    } while( 0 );
+
+    TRACUCOMP( g_trac_nc,EXIT_MRK"ncddRead: "
+               TRACE_ERR_FMT,
+               TRACE_ERR_ARGS(err));
+
+    return err;
+
+} // end ncddRead
+
+errlHndl_t ncddWrite (node_comm_args_t & i_args)
+{
+    errlHndl_t err = nullptr;
+
+    do
+    {
+    // Write data to data movement register
+    err = ncddRegisterOp( DeviceFW::WRITE,
+                          i_args.data_ptr,
+                          NCDD_REG_DATA,
+                          i_args );
+
+    if(err)
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"ncddWrite: SCOM deviceWrite call "
+            "failed for Target HUID 0x%08X and address 0x%016llX. "
+            TRACE_ERR_FMT,
+            i_args.tgt_huid,
+            NCDD_REG_DATA,
+            TRACE_ERR_ARGS(err));
+        break;
+    }
+
+
+    // Write Control Reg to send the data
+    ctrl_reg_t ctrl_reg_cmd;
+    ctrl_reg_cmd.value = 0x0;
+
+    ctrl_reg_cmd.start_stop = 1; // to start the command
+    ctrl_reg_cmd.write_not_read = 1;  // write command
+    ctrl_reg_cmd.mbox_id = i_args.mboxId;
+    ctrl_reg_cmd.link_id = i_args.linkId;
+
+
+   err = ncddRegisterOp( DeviceFW::WRITE,
+                          &ctrl_reg_cmd.value,
+                          NCDD_REG_CTRL,
+                          i_args );
+
+    if(err)
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"ncddWrite: SCOM deviceWrite call "
+            "failed for Target HUID 0x%08X and address 0x%016llX. "
+            TRACE_ERR_FMT,
+            i_args.tgt_huid,
+            NCDD_REG_CTRL,
+            TRACE_ERR_ARGS(err));
+        break;
+    }
+
+    // Wait for command to be complete
+    err = ncddWaitForCmdComp(i_args);
+    if(err)
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"ncddWrite: Wait For Cmd Complete "
+            "failed for Target HUID 0x%08X. "
+            TRACE_ERR_FMT,
+            i_args.tgt_huid,
+            TRACE_ERR_ARGS(err));
+        break;
+    }
+
+    // @TODO RTC 191008 - have ncddWaitForCmdComp return status to
+    // check for 'write' bit being set
+
+    } while( 0 );
+
+    TRACUCOMP( g_trac_nc,EXIT_MRK"ncddWrite: "
+               TRACE_ERR_FMT,
+               TRACE_ERR_ARGS(err));
+
+    return err;
+
+} // end ncddWrite
+
+
+errlHndl_t ncddCheckStatus (node_comm_args_t & i_args,
+                            const ctrl_reg_t i_statusVal )
+{
+    errlHndl_t err = nullptr;
+    bool errorFound = false;
+
+    TRACUCOMP( g_trac_nc,
+               ENTER_MRK"ncddCheckStatus(): Tgt=0x%X: 0x%.16llX",
+               i_args.tgt_huid,
+               i_statusVal.value );
+
+    do
+    {
+        if( 1 == i_statusVal.bad_addr )
+        {
+            errorFound = true;
+            TRACFCOMP(g_trac_nc,ERR_MRK
+                      "Node Comm DD: Bad Address! - status reg: 0x%016llx",
+                      i_statusVal.value );
+        }
+
+        if( 1 == i_statusVal.link_down )
+        {
+            errorFound = true;
+            TRACFCOMP(g_trac_nc,ERR_MRK
+                      "Node Comm DD: Link Down! - status reg: 0x%016llx",
+                      i_statusVal.value );
+        }
+
+        if( 1 == i_statusVal.corrupt )
+        {
+            errorFound = true;
+            TRACFCOMP(g_trac_nc,ERR_MRK
+                      "Node Comm DD: Corrupt! - status reg: 0x%016llx",
+                      i_statusVal.value );
+        }
+
+        if( 1 == i_statusVal.bad_write )
+        {
+            errorFound = true;
+            TRACFCOMP(g_trac_nc,ERR_MRK
+                      "Node Comm DD: Bad Write! - status reg: 0x%016llx",
+                      i_statusVal.value );
+        }
+
+        // Create Error Log
+        if( errorFound )
+        {
+            TRACFCOMP( g_trac_nc,
+                       ERR_MRK"ncddCheckStatus() - Error(s) found on "
+                       "Target 0x%X",
+                       i_args.tgt_huid );
+
+            /*@
+             * @errortype
+             * @reasoncode       RC_NCDD_HW_ERROR_FOUND
+             * @moduleid         MOD_NCDD_CHECK_FOR_ERRORS
+             * @userdata1        Status Register Value
+             * @userdata2        Target HUID
+             * @devdesc          Error found in Node Comm status/ctrl register
+             * @custdesc         Secure Boot failure
+             */
+            err = new ERRORLOG::ErrlEntry( ERRORLOG::ERRL_SEV_UNRECOVERABLE,
+                                           MOD_NCDD_CHECK_FOR_ERRORS,
+                                           RC_NCDD_HW_ERROR_FOUND,
+                                           i_statusVal.value,
+                                           i_args.tgt_huid);
+
+            // Likely an issue with Processor or its bus
+            err->addHwCallout( i_args.tgt,
+                               HWAS::SRCI_PRIORITY_HIGH,
+                               HWAS::DELAYED_DECONFIG,
+                               HWAS::GARD_NULL );
+
+            // Or HB code failed to do the procedure correctly
+            err->addProcedureCallout(HWAS::EPUB_PRC_HB_CODE,
+                                     HWAS::SRCI_PRIORITY_MED);
+
+            // @TODO RTC 184518 - Look into bus callouts
+
+           break;
+        }
+
+
+    } while( 0 );
+
+    TRACUCOMP( g_trac_nc,EXIT_MRK"ncddCheckStatus: "
+               TRACE_ERR_FMT,
+               TRACE_ERR_ARGS(err));
+
+    return err;
+
+} // end ncddCheckStatus
+
+
+errlHndl_t ncddWaitForCmdComp (node_comm_args_t & i_args)
+{
+    errlHndl_t err = nullptr;
+    uint64_t interval_ns  = NODE_COMM_POLL_DELAY_NS;
+    int timeout_ns = NODE_COMM_POLL_DELAY_TOTAL_NS;
+    ctrl_reg_t ctrl_reg_status;
+
+
+    TRACUCOMP(g_trac_nc, "ncddWaitForCmdComp(): timeout_ns=%d, "
+              "interval_ns=%d", timeout_ns, interval_ns);
+
+    do
+    {
+        do
+        {
+            // Read Control Reg to check for status
+            ctrl_reg_status.value = 0x0;
+
+            err = ncddRegisterOp( DeviceFW::READ,
+                                  &ctrl_reg_status.value,
+                                  NCDD_REG_CTRL,
+                                  i_args );
+            if(err)
+            {
+                TRACFCOMP(g_trac_nc,ERR_MRK"ncddWaitForCmdComp: ncddRegisterOp "
+                          "failed for Target HUID 0x%08X and address 0x%016llX. "
+                          TRACE_ERR_FMT,
+                          i_args.tgt_huid,
+                          NCDD_REG_CTRL,
+                          TRACE_ERR_ARGS(err));
+                break;
+            }
+
+            // Check For Errors
+            err = ncddCheckStatus(i_args, ctrl_reg_status);
+            if(err)
+            {
+                TRACFCOMP(g_trac_nc,ERR_MRK"ncddWaitForCmdComp: ncddCheckStatus"
+                          " failed for Target HUID 0x%08X, address 0x%016llX. "
+                          TRACE_ERR_FMT,
+                          i_args.tgt_huid,
+                          NCDD_REG_CTRL,
+                          TRACE_ERR_ARGS(err));
+                break;
+            }
+
+            // Check if we have more time to poll
+            if (timeout_ns < 0)
+            {
+                TRACFCOMP(g_trac_nc,
+                          ERR_MRK"ncddWaitForCmdComp() - "
+                          "Timed out waiting for Command Complete! "
+                          "status=0x%016llX from reg=0x%016llX",
+                          ctrl_reg_status.value, NCDD_REG_CTRL);
+
+                /*@
+                 * @errortype
+                 * @reasoncode       RC_NCDD_CMD_COMP_TIMEOUT
+                 * @moduleid         MOD_NCDD_WAIT_FOR_CMD_COMP
+                 * @userdata1        Status Register Value
+                 * @userdata2[0:31]  Status/Control Register Address
+                 * @userdata2[32:63] Target HUID
+                 * @devdesc          Timed out waiting for command complete.
+                 * @custdesc         Secure Boot failure
+                 */
+                err = new ERRORLOG::ErrlEntry(ERRORLOG::ERRL_SEV_UNRECOVERABLE,
+                                              MOD_NCDD_WAIT_FOR_CMD_COMP,
+                                              RC_NCDD_CMD_COMP_TIMEOUT,
+                                              ctrl_reg_status.value,
+                                              TWO_UINT32_TO_UINT64(
+                                                NCDD_REG_CTRL,
+                                                i_args.tgt_huid));
+
+                // Likely an issue with Processor or its bus
+                err->addHwCallout(i_args.tgt,
+                                  HWAS::SRCI_PRIORITY_HIGH,
+                                  HWAS::DELAYED_DECONFIG,
+                                  HWAS::GARD_NULL);
+
+                // Or HB code failed to do the procedure correctly
+                err->addProcedureCallout(HWAS::EPUB_PRC_HB_CODE,
+                                         HWAS::SRCI_PRIORITY_MED);
+
+                // @TODO RTC 184518 - Look into bus callouts
+
+                break;
+            }
+
+            // Sleep before polling again
+            nanosleep( 0, interval_ns );
+            timeout_ns -= interval_ns;
+
+         } while( 1 == ctrl_reg_status.start_stop ); /* Cmd Complete when ==0 */
+
+         if (err)
+         {
+             break;
+         }
+
+    } while (0);
+
+    TRACUCOMP( g_trac_nc,EXIT_MRK"ncddWaitForCmdComp: "
+               TRACE_ERR_FMT,
+               TRACE_ERR_ARGS(err));
+
+    return err;
+
+} // end ncddWaitForCmdComp
+
+errlHndl_t ncddRegisterOp ( DeviceFW::OperationType i_opType,
+                            uint64_t * io_data_64,
+                            uint64_t i_reg,
+                            node_comm_args_t & i_args )
+{
+    errlHndl_t err = nullptr;
+    const size_t expSize = sizeof(i_reg);
+    uint64_t l_reg = getLinkMboxRegAddr(i_reg, i_args.mode);
+
+    TRACUCOMP(g_trac_nc,ENTER_MRK"ncddRegisterOp: %s: %s: "
+              "tgt=0x%X, reg_addr=0x%.16llX, data=0x%.16llX",
+              (i_args.mode == NCDD_MODE_ABUS)
+                ? NCDD_ABUS_STRING : NCDD_XBUS_STRING,
+              ( i_opType == DeviceFW::READ ) ? "read" : "write",
+              i_args.tgt_huid,
+              l_reg, (*io_data_64)) ;
+
+    do
+    {
+    uint64_t reqSize = expSize;
+    err = DeviceFW::deviceOp( i_opType,
+                              i_args.tgt,
+                              io_data_64,
+                              reqSize,
+                              DEVICE_SCOM_ADDRESS(l_reg));
+
+    if(err)
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"ncddRegisterOp %s %s Fail! "
+                  TRACE_ERR_FMT
+                  " tgt=0x%X, reg_addr=0x%.8X, data=0x%.16X",
+                  (i_args.mode == NCDD_MODE_ABUS)
+                    ? NCDD_ABUS_STRING : NCDD_XBUS_STRING,
+                  ( i_opType == DeviceFW::READ ) ? "read" : "write",
+                  TRACE_ERR_ARGS(err),
+                  i_args.tgt_huid,
+                  l_reg, (*io_data_64) );
+            break;
+        }
+    assert(reqSize==expSize,"ncddRegisterOp: SCOM deviceRead didn't return expected data size of %d (it was %d)",
+           expSize,reqSize);
+
+    } while (0);
+
+    TRACUCOMP(g_trac_nc,EXIT_MRK"ncddRegisterOp: %s: %s: "
+              "tgt=0x%X, reg_addr=0x%.16llX, data=0x%.16llX. "
+              TRACE_ERR_FMT,
+              (i_args.mode == NCDD_MODE_ABUS)
+                ? NCDD_ABUS_STRING : NCDD_XBUS_STRING,
+              ( i_opType == DeviceFW::READ ) ? "read" : "write",
+              i_args.tgt_huid,
+              l_reg, (*io_data_64),
+              TRACE_ERR_ARGS(err));
+
+    return err;
+
+} // end ncddRegisterOp
+
+
+} // end NODECOMM namespace
+
+} // end SECUREBOOT namespace
+
diff --git a/src/usr/secureboot/node_comm/node_comm_dd.H b/src/usr/secureboot/node_comm/node_comm_dd.H
new file mode 100644
index 000000000..a42ce7fd0
--- /dev/null
+++ b/src/usr/secureboot/node_comm/node_comm_dd.H
@@ -0,0 +1,220 @@
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: src/usr/secureboot/node_comm/node_comm_dd.H $                 */
+/*                                                                        */
+/* OpenPOWER HostBoot Project                                             */
+/*                                                                        */
+/* Contributors Listed Below - COPYRIGHT 2018                             */
+/* [+] International Business Machines Corp.                              */
+/*                                                                        */
+/*                                                                        */
+/* Licensed under the Apache License, Version 2.0 (the "License");        */
+/* you may not use this file except in compliance with the License.       */
+/* You may obtain a copy of the License at                                */
+/*                                                                        */
+/*     http://www.apache.org/licenses/LICENSE-2.0                         */
+/*                                                                        */
+/* Unless required by applicable law or agreed to in writing, software    */
+/* distributed under the License is distributed on an "AS IS" BASIS,      */
+/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or        */
+/* implied. See the License for the specific language governing           */
+/* permissions and limitations under the License.                         */
+/*                                                                        */
+/* IBM_PROLOG_END_TAG                                                     */
+#ifndef __NODE_COMM_DD_H
+#define __NODE_COMM_DD_H
+
+// ----------------------------------------------
+// Includes
+// ----------------------------------------------
+#include <config.h>
+#include <devicefw/userif.H>
+#include <secureboot/nodecommif.H>
+
+namespace SECUREBOOT
+{
+
+namespace NODECOMM
+{
+
+/**
+ * @brief Struct used to pass basic Node Communication operations
+ *        information between functions
+ */
+struct node_comm_args_t
+{
+    TARGETING::Target* tgt;
+    uint32_t tgt_huid;
+    node_comm_modes_t mode;
+    uint8_t linkId;
+    uint8_t mboxId;
+    uint64_t* data_ptr;
+
+    node_comm_args_t():tgt(nullptr),
+                       tgt_huid(0x0),
+                       mode(NCDD_MODE_INVALID),
+                       linkId(NCDD_INVALID_LINK_MBOX),
+                       mboxId(NCDD_INVALID_LINK_MBOX),
+                       data_ptr(nullptr){};
+};
+
+
+/**
+ * @brief Node Comm Contol (and Status) Register Definition
+ *
+ * @note  Certain bits are used to start an operation, provide status of the
+ *        operation, and flag errors in the operation.
+ */
+union ctrl_reg_t
+{
+    uint64_t value;
+    struct
+    {
+        uint64_t start_stop : 1;  // set to start op; HW sets to 0 when op done
+        uint64_t write_not_read : 1;
+        uint64_t bad_addr : 1;
+        uint64_t link_down : 1;
+        uint64_t corrupt : 1;
+        uint64_t sent : 1;
+        uint64_t bad_write : 1;
+        uint64_t reset : 1;
+        uint64_t mbox_id : 1;
+        uint64_t link_id : 3;
+        uint64_t reserved : 52;
+
+    } PACKED;
+};
+
+
+/**
+*
+* @brief Perform a Node Comm operation.  It follows a pre-defined
+*       prototype function in order to be registered with the device
+*       driver framework.
+*
+* @param[in] i_opType - Operation Type - See DeviceFW::OperationType in
+*       driverif.H
+*
+* @param[in] i_target - Processor Target
+*                       Code will fail if nullptr or not TYPE_PROC
+*
+* @param [in/out] io_buffer
+*       INPUT: Pointer to the data that will be  written to the target device
+*       OUTPUT: Pointer to the data that was read from the target device
+*
+* @param [in/out] io_buflen
+*       INPUT: Length of the buffer to be written to target device
+*       OUTPUT: Length of buffer that was written, or length of buffer
+*           to be read from target device
+*       NOTE:  For Both INPUT and OUTPUT this should be 8-bytes (64-bits)
+*
+* @param [in] i_accessType - Access Type - See DeviceFW::AccessType in
+*       userif.H
+*
+* @param [in] i_args - This is an argument list for the device driver
+*       framework.  This list of arguments is documented in userif.H.
+*
+* @return errlHndl_t - NULL if successful, otherwise a pointer to the
+*       error log.
+*
+*/
+errlHndl_t nodeCommPerformOp( DeviceFW::OperationType i_opType,
+                         TARGETING::Target * i_target,
+                         void * io_buffer,
+                         size_t & io_buflen,
+                         int64_t i_accessType,
+                         va_list i_args );
+
+/**
+ * @brief Reads data From ABUS/XBUS Link Mailbox Register
+ *
+ * @param[in/out] io_args - Structure containing arguments needed for a command
+ *                          transaction and it holds the resulting data
+ *
+ * @return errlHndl_t - nullptr if successful, otherwise a pointer to
+ *                      the error log.
+ */
+errlHndl_t ncddRead (node_comm_args_t & io_args);
+
+/**
+ * @brief Writes data to ABUS/XBUS Link Mailbox Data Movement Register and then
+ *        sends data via Link Bus Mailbox capability
+ *
+ * @param[in] i_args - Structure containing arguments needed for a command
+ *                     transaction.
+ *
+ * @return errlHndl_t - nullptr if successful, otherwise a pointer to
+ *                      the error log.
+ */
+errlHndl_t ncddWrite (node_comm_args_t & i_args);
+
+/**
+ * @brief Checks the status in the ABUS/XBUS Link Mailbox Control Register
+ *
+ * @param[in] i_args - Structure containing arguments needed for a command
+ *                     transaction.
+ *
+ * @param[in] i_statusVal - Control Register value to be checked
+ *
+ * @return errlHndl_t - nullptr if successful and the command is complete;
+ *                      otherwise a pointer to the error log.
+ */
+errlHndl_t ncddCheckForErrors (node_comm_args_t & i_args,
+                               ctrl_reg_t i_statusVal );
+
+/**
+ * @brief Waits for the operation to complete or timeout while
+ *        periodically checking the status for errors
+ *
+ * @param[in] i_args - Structure containing arguments needed for a command
+ *                     transaction.
+ *
+ * @return errlHndl_t - nullptr if successful and the command is complete;
+ *                      otherwise a pointer to the error log.
+ */
+errlHndl_t ncddWaitForCmdComp (node_comm_args_t & i_args);
+
+/**
+ * @brief Analyzes an error handle object and performs any
+ *        reset activity, if necessary
+ *
+ * @param[in] i_err - The error to analyze
+ * @param[in] i_args - miscellaneous arguments
+ *
+ * @return void
+ */
+// @TODO RTC:191008 Implement simple reset functionality
+void ncddHandleError( errlHndl_t & i_err,
+                      node_comm_args_t & i_args ){};
+
+
+/**
+ * @brief This function handles all Node Communications-related SCOM operations
+ *
+ * @param[in] i_opType - Operation Type - See DeviceFW::OperationType in
+ *       driververif.H
+ *
+ * @param [in/out] io_buffer_64
+ *       INPUT: Pointer to 64 bits of data to be  written to the target
+ *       OUTPUT: Pointer to the 64 bits of data that was read from the target
+ *
+ * @param[in] i_reg - The SCOM register of the operation
+ *
+ * @param[in/out] i_args - Structure containing arguments needed for a command
+ *                         transaction and holds resulting data, if applicable
+ *
+ * @return errHndl_t - NULL if successful, otherwise a pointer to
+ *                     the error log.
+ */
+errlHndl_t ncddRegisterOp ( DeviceFW::OperationType i_opType,
+                            uint64_t * io_data_64,
+                            uint64_t i_reg,
+                            node_comm_args_t & i_args );
+
+} // end NODECOMM namespace
+
+} // end SECUREBOOT namespace
+
+#endif // End __NODE_COMM_DD_H
+
diff --git a/src/usr/secureboot/node_comm/node_comm_test.C b/src/usr/secureboot/node_comm/node_comm_test.C
new file mode 100644
index 000000000..6b034361a
--- /dev/null
+++ b/src/usr/secureboot/node_comm/node_comm_test.C
@@ -0,0 +1,296 @@
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: src/usr/secureboot/node_comm/node_comm_test.C $               */
+/*                                                                        */
+/* OpenPOWER HostBoot Project                                             */
+/*                                                                        */
+/* Contributors Listed Below - COPYRIGHT 2018                             */
+/* [+] International Business Machines Corp.                              */
+/*                                                                        */
+/*                                                                        */
+/* Licensed under the Apache License, Version 2.0 (the "License");        */
+/* you may not use this file except in compliance with the License.       */
+/* You may obtain a copy of the License at                                */
+/*                                                                        */
+/*     http://www.apache.org/licenses/LICENSE-2.0                         */
+/*                                                                        */
+/* Unless required by applicable law or agreed to in writing, software    */
+/* distributed under the License is distributed on an "AS IS" BASIS,      */
+/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or        */
+/* implied. See the License for the specific language governing           */
+/* permissions and limitations under the License.                         */
+/*                                                                        */
+/* IBM_PROLOG_END_TAG                                                     */
+/**
+ * @file node_comm_test.C
+ *
+ * @brief Implementation of the Secure Node Communications Tests
+ *
+ */
+
+// ----------------------------------------------
+// Includes
+// ----------------------------------------------
+#include <string.h>
+#include <trace/interface.H>
+#include <errl/errlentry.H>
+#include <errl/errlmanager.H>
+#include <errl/errludtarget.H>
+#include <targeting/common/targetservice.H>
+#include <devicefw/userif.H>
+#include <devicefw/driverif.H>
+#include <secureboot/secure_reasoncodes.H>
+#include <secureboot/nodecommif.H>
+#include <targeting/common/commontargeting.H>
+#include <targeting/common/utilFilter.H>
+
+#include "node_comm.H"
+
+
+using   namespace   TARGETING;
+
+namespace SECUREBOOT
+{
+
+namespace NODECOMM
+{
+
+/**
+ *  @brief Execute A Single Transmission from one proc to another over Xbus
+ */
+errlHndl_t nodeCommXbus2ProcTest(void)
+{
+    errlHndl_t err = nullptr;
+    const uint64_t gold_data = 0xFEEDB0B0DEADBEEF;
+    uint64_t sent_data = gold_data;
+    uint64_t read_data = 0;
+    Target* read_tgt = nullptr;
+    node_comm_modes_t mode = NCDD_MODE_XBUS;
+    uint64_t linkId = 0;
+    uint64_t mboxId = 0;
+    bool attn_found = false;
+
+    do
+    {
+
+    // Get a list of all the procs in the system
+    TARGETING::TargetHandleList l_cpuTargetList;
+    getAllChips(l_cpuTargetList, TYPE_PROC);
+
+    // Need at least 2 procs for this test
+    if ( l_cpuTargetList.size() < 2 )
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"nodeCommXbus2ProcTest: need at least "
+                  "2 procs - only have %d",
+                  l_cpuTargetList.size());
+
+        break;
+    }
+
+    TRACUCOMP(g_trac_nc,ENTER_MRK"nodeCommXbus2ProcTest: Running with %d procs",
+              l_cpuTargetList.size());
+
+    // 1) Send Data Out of First Proc Xbus Link Mailbox
+    // @TODO RTC 184516 revisit this when PEER_PATH attribute is being used
+    if ( l_cpuTargetList.size() != 4)
+    {
+        linkId = 4;
+        mboxId = 0;
+    }
+    else
+    {
+        linkId = 0;
+        mboxId = 0;
+    }
+    TARGETING::Target* proc0 = (l_cpuTargetList[0]);
+    size_t size=sizeof(sent_data);
+
+    TRACFCOMP(g_trac_nc,"nodeCommXbus2ProcTest: "
+              "Sending 0x%016llX to L%d/M%d Using proc0=0x%X",
+              sent_data, linkId, mboxId, TARGETING::get_huid(proc0));
+
+    err = DeviceFW::deviceWrite(proc0,
+                                &sent_data,
+                                size,
+                                DEVICE_NODECOMM_ADDRESS(mode, linkId, mboxId));
+
+    if (err)
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"nodeCommXbus2ProcTest: Error Back From "
+                  "Xbus MBox Send: Tgt=0x%X, link=%d, mbox=%d: "
+                  TRACE_ERR_FMT,
+                  get_huid(proc0), linkId, mboxId,
+                  TRACE_ERR_ARGS(err));
+        break;
+    }
+
+    // 2) Loop through targets to see which of them had an attention
+    for (const auto & l_cpu_target: l_cpuTargetList)
+    {
+        attn_found = false;
+        read_tgt = l_cpu_target;
+
+        err = nodeCommMapAttn(read_tgt, mode, attn_found, linkId, mboxId);
+        if (err)
+        {
+            TRACFCOMP(g_trac_nc,ERR_MRK"nodeCommXbus2ProcTest: Error Back From "
+                      "Map Attn: Tgt=0x%X, attn_found=%d, link=%d, mbox=%d: "
+                      TRACE_ERR_FMT,
+                      get_huid(read_tgt), attn_found, linkId, mboxId,
+                      TRACE_ERR_ARGS(err));
+            break;
+        }
+        if (attn_found == true)
+        {
+            break;
+        }
+    }
+    if(err)
+    {
+        break;
+    }
+
+    if (attn_found == false)
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"nodeCommXbus2ProcTest: "
+                  "No attentions were found! (%d)",
+                  attn_found);
+
+        /*@
+         * @errortype
+         * @reasoncode       RC_NC_NO_ATTN_FOUND
+         * @moduleid         MOD_NC_XBUS_TEST
+         * @userdata1        Data Sent
+         * @userdata2[0:15]  LinkId data was sent from
+         * @userdata2[16:31] MboxId data was sent from
+         * @userdata2[32:63] Target HUID data was sent from
+         * @devdesc          No Attention was found after sending data in
+         *                   XBUS Node Comm Test
+         * @custdesc         Secure Boot failure
+         */
+        err = new ERRORLOG::ErrlEntry( ERRORLOG::ERRL_SEV_UNRECOVERABLE,
+                                       MOD_NC_XBUS_TEST,
+                                       RC_NC_NO_ATTN_FOUND,
+                                       sent_data,
+                                       TWO_UINT16_ONE_UINT32_TO_UINT64(
+                                         linkId,
+                                         mboxId,
+                                         get_huid(proc0)));
+
+        // Likely HB code failed to do the procedure correctly
+        err->addProcedureCallout(HWAS::EPUB_PRC_HB_CODE,
+                                 HWAS::SRCI_PRIORITY_HIGH);
+
+        // Or unlikely an issue with Processor or its bus
+        err->addHwCallout( proc0,
+                           HWAS::SRCI_PRIORITY_LOW,
+                           HWAS::NO_DECONFIG,
+                           HWAS::GARD_NULL );
+        break;
+    }
+    else
+    {
+        TRACUCOMP(g_trac_nc,INFO_MRK"nodeCommXbus2ProcTest: "
+                  "Attention was found (%d) on tgt=0x%.08X",
+                  attn_found, get_huid(read_tgt));
+    }
+
+
+    // 3) Read message on proc with Link Mailbox found above
+    TRACFCOMP(g_trac_nc,"nodeCommXbus2ProcTest: Attention Found on"
+              "proc=0x%X for L%d/M%d ",
+              TARGETING::get_huid(read_tgt), linkId, mboxId);
+
+    err = DeviceFW::deviceRead(read_tgt,
+                               &read_data,
+                               size,
+                               DEVICE_NODECOMM_ADDRESS(mode, linkId, mboxId));
+    if (err)
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"nodeCommXbus2ProcTest: Error Back From "
+                  "Xbus MBox Read: Tgt=0x%X, link=%d, mbox=%d: "
+                  TRACE_ERR_FMT,
+                  get_huid(read_tgt), linkId, mboxId,
+                  TRACE_ERR_ARGS(err));
+        break;
+    }
+
+    // 4) Compare values
+    if (read_data == gold_data)
+    {
+        TRACFCOMP(g_trac_nc,INFO_MRK"nodeCommXbus2ProcTest: "
+                  "DATA SUCCESSFULLY READ BACK = 0x%.16llx from "
+                  "proc=0x%X's L%d/M%d Mailbox"
+                  "L%d/M%d using proc=0x%X",
+                  read_data, TARGETING::get_huid(read_tgt), linkId, mboxId);
+    }
+    else
+    {
+        TRACFCOMP(g_trac_nc,ERR_MRK"nodeCommXbus2ProcTest: "
+                  "DATA NOT READ BACK! Got 0x%.16llx; should be 0x%.16llX. "
+                  "Read from proc=0x%X's L%d/M%d Mailbox",
+                  read_data, gold_data, TARGETING::get_huid(read_tgt), linkId, mboxId);
+
+        /*@
+         * @errortype
+         * @reasoncode       RC_NC_DATA_MISCOMPARE
+         * @moduleid         MOD_NC_XBUS_TEST
+         * @userdata1        Data Read Back
+         * @userdata2[0:15]  LinkId data was read from
+         * @userdata2[16:31] MboxId data was read from
+         * @userdata2[32:63] Target HUID data was read from
+         * @devdesc          No Attention was found after sending data in
+         *                   Xbus Node Comm Test
+         * @custdesc         Secure Boot failure
+         */
+        err = new ERRORLOG::ErrlEntry( ERRORLOG::ERRL_SEV_UNRECOVERABLE,
+                                       MOD_NC_XBUS_TEST,
+                                       RC_NC_DATA_MISCOMPARE,
+                                       read_data,
+                                       TWO_UINT16_ONE_UINT32_TO_UINT64(
+                                         linkId,
+                                         mboxId,
+                                         get_huid(read_tgt)));
+
+        // Likely HB code failed to do the procedure correctly
+        err->addProcedureCallout(HWAS::EPUB_PRC_HB_CODE,
+                                 HWAS::SRCI_PRIORITY_HIGH);
+
+        // Or unlikely an issue with Processor or its bus
+        err->addHwCallout( read_tgt,
+                           HWAS::SRCI_PRIORITY_LOW,
+                           HWAS::NO_DECONFIG,
+                           HWAS::GARD_NULL );
+
+    }
+
+    } while( 0 );
+
+    TRACFCOMP(g_trac_nc,EXIT_MRK"nodeCommXbus2ProcTest: "
+              TRACE_ERR_FMT
+              "Tgt=0x%X, attn_found=%d, link=%d, mbox=%d",
+              TRACE_ERR_ARGS(err),
+              get_huid(read_tgt), attn_found, linkId, mboxId);
+
+    if (err)
+    {
+        err->collectTrace(SECURE_COMP_NAME);
+        err->collectTrace(NODECOMM_TRACE_NAME);
+
+        // @TODO RTC:191008 Delete for now as it will fail in simics and
+        // cause a processor deconfig.
+        delete err;
+        err = nullptr;
+    }
+
+    return err;
+
+} // end of nodeCommXbus2ProcTest
+
+} // End NODECOMM namespace
+
+} // End SECUREBOOT namespace
+
+
+