Initialise PIBMEM

Change-Id: I826378d6d22bca69b776024f0f42cf36952c3141
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/27568
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Reviewed-by: AMIT J. TENDOLKAR <amit.tendolkar@in.ibm.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/sbe/image/base_loader.c b/sbe/image/base_loader.c
index b5ea0235..bcb76794 100644
--- a/sbe/image/base_loader.c
+++ b/sbe/image/base_loader.c
@@ -1,3 +1,27 @@
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: sbe/image/base_loader.c $                                     */
+/*                                                                        */
+/* OpenPOWER sbe Project                                                  */
+/*                                                                        */
+/* Contributors Listed Below - COPYRIGHT 2015,2016                        */
+/* [+] 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                                                     */
 #include "sbeXipUtils.H"
 
 // Load section to destination address
@@ -22,6 +46,36 @@ int32_t base_loader()
     P9XipHeader *hdr = getXipHdr();
 
     uint64_t *pibMemAddr  = (uint64_t *)g_pibMemAddr;
+    uint64_t *tempPibMemAddr  = (uint64_t *)g_pibMemAddr;
+    uint64_t *pibEndAddr  = (uint64_t *)(SBE_LOADER_BASE_ORIGIN);
+
+    // Initialise complete PIBMEM with 0
+    // Though this is inefficient, this is quick fix to solve the
+    // HW write of data which is not 8 byte alligned. All write which
+    // are not 8 byte alligned, translates to read-modify-write. So
+    // if code does a write for 4 byte, first HW will read 8 bytes. If
+    // there is no data written there earlier and random data is present
+    // it can cause ecc errors.
+    // TODO via RTC 158797
+    // Though we may be able to optimise it, but than we have to put the
+    // logic in loadSection function which is not desired. So currently
+    // initialising all PIBMEM. If performance become concern during initial
+    // SBE load, we can optimise this.
+    // We have three options here in optimisation
+    //   1.  Put this logic in SEEPROM loader ( pmloader ). This was we can
+    //       reclaim space taken by base loader as stack/bss can grow in base
+    //       loader section after image load.
+    //   2.  Keep this code in PIBMEM. But do not initialise the memory taken
+    //       by base image.
+    //   3.  Do what is done in option 1 but only initialise memoty after base
+    //       section to end of PIBMEM. This will involve some more hardcoding
+    //       in seeprom loader.
+    // My preference will be option 1 but depends upon performance goals.
+    for( ; tempPibMemAddr < pibEndAddr; tempPibMemAddr++ )
+    {
+        *tempPibMemAddr = 0;
+    }
+
     loadSection(&(hdr->iv_section[P9_XIP_SECTION_SBE_BASE]), pibMemAddr);
     // Set the IVPR register. This is required so that interrupt vector table
     // points to pk interfaces.