Force 25G Nvlink speed on P9N DD2.1

 Normally the OBUS PLL frequency is controlled via the MRW,
 however P9NDD2.1 has a bug that forces the OBus freq to 25G.

 Desire is to allow the MRW to set to a higher freq, but MRW
 doesn't have entries for per chip EC, so this commit just
 handles down leveling P9N DD2.1 (as a chip restriction)

Change-Id: I542f7810a69facb919cc3889ae3ed5ca0a233445
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/55195
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>
Reviewed-by: William G. Hoffa <wghoffa@us.ibm.com>
CI-Ready: Dean Sanner <dsanner@us.ibm.com>
CI-Ready: Corey V. Swenson <cswenson@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: ERICH J. HAUPTLI <ejhauptl@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

src/include/arch/pvrformat.H

@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2017                             */
+/* Contributors Listed Below - COPYRIGHT 2017,2018                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
 /*                                                                        */
@@ -115,6 +115,8 @@ struct PVR_t
     {
         NIMBUS_DD1_MASK = 0x00FF2F0F,
         IS_NIMBUS_DD1   = 0x004E0100,
+        IS_NIMBUS_DD20   = 0x004E0200,
+        IS_NIMBUS_DD21   = 0x004E0201,
 
         // Field: chipType
         NIMBUS_CHIP = 0,
@@ -138,6 +140,22 @@ struct PVR_t
     inline bool isNimbusDD1() {
         return ((word & NIMBUS_DD1_MASK) == IS_NIMBUS_DD1);
     }
+
+    /**
+     * @brief Check if DD2.0
+     * @return true if DD2.0, else false
+     */
+    inline bool isNimbusDD20() {
+        return ((word & NIMBUS_DD1_MASK) == IS_NIMBUS_DD20);
+    }
+
+    /**
+     * @brief Check if DD2.1
+     * @return true if DD2.1, else false
+     */
+    inline bool isNimbusDD21() {
+        return ((word & NIMBUS_DD1_MASK) == IS_NIMBUS_DD21);
+    }
 };
 
 #endif //_PVRFORMAT_H

src/usr/isteps/istep06/call_host_voltage_config.C

@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2016,2017                        */
+/* Contributors Listed Below - COPYRIGHT 2016,2018                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
 /*                                                                        */
@@ -352,6 +352,25 @@ void* call_host_voltage_config( void *io_pArgs )
                     "ATTR_FREQ_X_MHZ = %d",
                     l_sys->getAttr<ATTR_FREQ_X_MHZ>());
 
+            //Nimbus DD21 only supports OBUS PLL of 1563(versus product of 1611)
+            //Force it because of a chip bug instead of letting MRW control
+            PVR_t l_pvr( mmio_pvr_read() & 0xFFFFFFFF );
+            if( l_pvr.isNimbusDD21() )
+            {
+                TRACFCOMP(ISTEPS_TRACE::g_trac_isteps_trace,
+                          "call_host_voltage_config.C::"
+                          "Nimbus DD2.1 -- Forcing ATTR_FREQ_X_MHZ = %d",
+                          l_sys->getAttr<ATTR_FREQ_X_MHZ>());
+
+                TARGETING::ATTR_FREQ_O_MHZ_type l_freq_array =
+                {OBUS_PLL_FREQ_LIST_P9N_21[0],OBUS_PLL_FREQ_LIST_P9N_21[0],
+                OBUS_PLL_FREQ_LIST_P9N_21[0], OBUS_PLL_FREQ_LIST_P9N_21[0]};
+                assert(l_proc->
+                       trySetAttr<TARGETING::ATTR_FREQ_O_MHZ>(l_freq_array),
+                       "call_host_voltage_config.C failed to set ATTR_FREQ_O_MHZ");
+            }
+
+
             // get the child EQ targets
             targetService().getAssociated(
                     l_eqList,