Change MCA initfile to not divide by 0 if there are no DIMM

Change-Id: I5ebcb11dba0c77d1bf9c107dd8e3e412ca3632ce
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/30761
Reviewed-by: STEPHEN GLANCY <sglancy@us.ibm.com>
Reviewed-by: Jenny Huynh <jhuynh@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Reviewed-by: Prachi Gupta <pragupta@us.ibm.com>
Tested-by: Hostboot CI <hostboot-ci+hostboot@us.ibm.com>
Reviewed-by: Brian R. Silver <bsilver@us.ibm.com>
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/30769
Reviewed-by: Hostboot Team <hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

2 files changed, 17 insertions, 4 deletions

diff --git a/src/import/chips/p9/initfiles/p9.mca.scom.initfile b/src/import/chips/p9/initfiles/p9.mca.scom.initfile
index 47cd87692..5cbb0ec0f 100644
--- a/src/import/chips/p9/initfiles/p9.mca.scom.initfile
+++ b/src/import/chips/p9/initfiles/p9.mca.scom.initfile
@@ -114,14 +114,22 @@ define def_MEM_TYPE_2667_20_20_20   =   def_MSS_FREQ_EQ_2667    &&  ( MCS.ATTR_E
 
 define def_NUM_RANKS            = (   MCS.ATTR_EFF_NUM_RANKS_PER_DIMM[def_PORT_INDEX][0]
                                     + MCS.ATTR_EFF_NUM_RANKS_PER_DIMM[def_PORT_INDEX][1] );
+
+# We don't have a div 0 problem here as we don't run this if we don't have DIMM so the number of ranks won't be 0.
 define def_REFRESH_INTERVAL     =   ((MCS.ATTR_EFF_DRAM_TREFI[def_PORT_INDEX])/(8*def_NUM_RANKS));
+
 define def_RANK_SWITCH_TCK      =   4 + ((MCBIST.ATTR_MSS_FREQ-1866)/267);         # 1866: 4  2133: 5  2400: 6  2667: 7
 define def_BUS_TURNAROUND_TCK   =   4 + ((MCBIST.ATTR_MSS_FREQ-1866)/267);         # 1866: 4  2133: 5  2400: 6  2667: 7
 
+# Funky ... If the attribute is 0, then the value of the == operation will be 1 which bitwise-or'd with 0 gives us 1. If the attribute is != 0, then the
+# value of the == operation will be 0 which when bitwise-or'd with the attribute will give us the attribute value. Love, Prachi, Jenny, Shelton and Brian.
+define def_SLOT0_DENOMINATOR    = (MCS.ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[def_PORT_INDEX][0] == 0x0) | MCS.ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[def_PORT_INDEX][0];
+define def_SLOT1_DENOMINATOR    = (MCS.ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[def_PORT_INDEX][1] == 0x0) | MCS.ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[def_PORT_INDEX][1];
+
 define def_SLOT0_DRAM_STACK_HEIGHT = (   MCS.ATTR_EFF_NUM_RANKS_PER_DIMM[def_PORT_INDEX][0]
-                                       / MCS.ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[def_PORT_INDEX][0] );
+                                         / def_SLOT0_DENOMINATOR );
 define def_SLOT1_DRAM_STACK_HEIGHT = (   MCS.ATTR_EFF_NUM_RANKS_PER_DIMM[def_PORT_INDEX][1]
-                                       / MCS.ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[def_PORT_INDEX][1] );
+                                         / def_SLOT1_DENOMINATOR );
 
 #--******************************************************************************
 #-- Dial Assignments
diff --git a/src/import/chips/p9/procedures/hwp/initfiles/p9_mca_scom.C b/src/import/chips/p9/procedures/hwp/initfiles/p9_mca_scom.C
index 5d0e93792..895e5958a 100644
--- a/src/import/chips/p9/procedures/hwp/initfiles/p9_mca_scom.C
+++ b/src/import/chips/p9/procedures/hwp/initfiles/p9_mca_scom.C
@@ -68,6 +68,7 @@ constexpr auto literal_0b011000 = 0b011000;
 constexpr auto literal_0b000 = 0b000;
 constexpr auto literal_0b100 = 0b100;
 constexpr auto literal_0b010 = 0b010;
+constexpr auto literal_0x0 = 0x0;
 constexpr auto literal_0b001 = 0b001;
 constexpr auto literal_0b101 = 0b101;
 constexpr auto literal_0b011 = 0b011;
@@ -853,6 +854,8 @@ fapi2::ReturnCode p9_mca_scom(const fapi2::Target<fapi2::TARGET_TYPE_MCA>& TGT0,
             break;
         }
 
+        auto l_def_SLOT0_DENOMINATOR = ((l_TGT2_ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[l_def_PORT_INDEX][literal_0] == literal_0x0)
+                                        | l_TGT2_ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[l_def_PORT_INDEX][literal_0]);
         fapi2::ATTR_EFF_NUM_RANKS_PER_DIMM_Type l_TGT2_ATTR_EFF_NUM_RANKS_PER_DIMM;
         l_rc = FAPI_ATTR_GET(fapi2::ATTR_EFF_NUM_RANKS_PER_DIMM, TGT2, l_TGT2_ATTR_EFF_NUM_RANKS_PER_DIMM);
 
@@ -863,9 +866,11 @@ fapi2::ReturnCode p9_mca_scom(const fapi2::Target<fapi2::TARGET_TYPE_MCA>& TGT0,
         }
 
         auto l_def_SLOT0_DRAM_STACK_HEIGHT = (l_TGT2_ATTR_EFF_NUM_RANKS_PER_DIMM[l_def_PORT_INDEX][literal_0] /
-                                              l_TGT2_ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[l_def_PORT_INDEX][literal_0]);
+                                              l_def_SLOT0_DENOMINATOR);
+        auto l_def_SLOT1_DENOMINATOR = ((l_TGT2_ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[l_def_PORT_INDEX][literal_1] == literal_0x0)
+                                        | l_TGT2_ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[l_def_PORT_INDEX][literal_1]);
         auto l_def_SLOT1_DRAM_STACK_HEIGHT = (l_TGT2_ATTR_EFF_NUM_RANKS_PER_DIMM[l_def_PORT_INDEX][literal_1] /
-                                              l_TGT2_ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM[l_def_PORT_INDEX][literal_1]);
+                                              l_def_SLOT1_DENOMINATOR);
         {
             l_rc = fapi2::getScom( TGT0, 0x7010914ull, l_scom_buffer );