Copied PRD register access code from Hostboot project

This is just a straight copy from the Hostboot project. No modifications
have been made. Those will come in later commits.

Change-Id: Id9985f5542944ba88498b348b24b711fe2c30704
Signed-off-by: Zane Shelley <zshelle@us.ibm.com>
diff --git a/src/register/prdfHomRegisterAccess.H b/src/register/prdfHomRegisterAccess.H
new file mode 100755
index 0000000..6426b4a
--- /dev/null
+++ b/src/register/prdfHomRegisterAccess.H
@@ -0,0 +1,159 @@
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: src/usr/diag/prdf/common/framework/register/prdfHomRegisterAccess.H $ */
+/*                                                                        */
+/* OpenPOWER HostBoot Project                                             */
+/*                                                                        */
+/* Contributors Listed Below - COPYRIGHT 2012,2017                        */
+/* [+] 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 PRDFHOMREGISTERACCESS_H
+#define PRDFHOMREGISTERACCESS_H
+/**
+   @file prdfHomRegisterAccess.H
+   @brief Provide access to scan & scan com registers via the HOM
+*/
+
+
+//--------------------------------------------------------------------
+// Includes
+//--------------------------------------------------------------------
+
+#include <iipMopRegisterAccess.h>
+#include <vector>
+#include <prdfPlatServices.H>
+#include <prdfErrlUtil.H>
+#include <prdfGlobal.H>
+//--------------------------------------------------------------------
+//  Forward References
+//--------------------------------------------------------------------
+
+namespace PRDF
+{
+
+class ScomAccessor
+{
+  public:
+
+    /**
+     * @brief ctor
+     */
+    inline ScomAccessor() {}
+
+    /**
+     * @brief dtor
+     */
+    inline virtual ~ScomAccessor() {}
+
+    /**
+     * @brief Access the scan com register
+     * @param i_target    Target to access the register
+     * @param bs holds    data read or to write
+     * @param registerId  register address
+     * @param operation   [READ|WRITE]
+     * @returns SUCCESS or PRD_SCANCOM_FAILURE
+     * @pre bs.Length() must be size of register data to read/write
+     * @post For read operation, bs is modified to reflect hardware
+     *       register state
+     */
+    virtual uint32_t Access( TARGETING::TargetHandle_t i_target,
+                             BitString & bs,
+                             uint64_t registerId,
+                             MopRegisterAccess::Operation operation) const;
+
+  private:
+
+    /**
+     * @brief disable copy
+     */
+    ScomAccessor(const ScomAccessor &);
+
+    /**
+     * @brief disable assignment
+     */
+    ScomAccessor & operator=(const ScomAccessor &);
+
+};
+
+/**
+ *  @brief Singleton to access the only ScomService
+ */
+class ScomService;
+PRDF_DECLARE_SINGLETON(ScomService, theScomService);
+
+/**
+ *  @brief Returns a reference to the ScomService singleton
+ *
+ *  @return Reference to the ScomService
+ */
+ScomService& getScomService();
+
+/**
+ *  @brief ScomService class
+ */
+class ScomService
+{
+  public:
+
+    /**
+     *  @brief Construct ScomService
+     */
+    ScomService();
+
+    /**
+     *  @brief Destroys ScomService
+     */
+    ~ScomService();
+
+    /**
+     * @brief set the scom accessor to be used
+     *
+     * @param[in] i_ScomAccessor new scom accessor
+     */
+    void setScomAccessor(ScomAccessor & i_ScomAccessor);
+
+    /**
+     Access the scan com register
+     @param i_target Target to access the register
+     @param BitString - holds data read or to write
+     @param register address
+     @param [READ|WRITE]
+     @returns [SUCCESS|FAIL]
+     @pre bs.Length() must be size of register data to read/write
+     @post For read operation, bs is modified to reflect hardware register state
+     @note
+     */
+    virtual uint32_t Access(TARGETING::TargetHandle_t i_target,
+                            BitString & bs,
+                            uint64_t registerId,
+                            MopRegisterAccess::Operation operation) const;
+
+  private:
+
+    // Disable copy constructor / assignment operator
+    ScomService(const ScomService& i_right);
+    ScomService& operator=(const ScomService& i_right);
+
+    // Scom access to actual HW or Sim
+    ScomAccessor * iv_ScomAccessor;
+};
+
+} // End namespace PRDF
+
+#endif /* PRDFHOMREGISTERACCESS_H */