[PATCH V3 1/2] MdeModulePkg PeiCore: Improve PeiInstallPeiMemory() description

["Kubacki, Michael A" <michael.a.kubacki@intel.com>]

Updates the function description for PeiInstallPeiMemory () to be
more helpful. The description is based on that given in the PI
Specification Version 1.7.

Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Signed-off-by: Michael Kubacki <michael.a.kubacki@intel.com>
Reviewed-by: Jian J Wang <jian.j.wang@intel.com>
---

Notes:
    V3 Changes:
    1. Remove the change to PiPeiCis.h as it is moved to a separate
       patch.
    
    V2 Changes:
    1. Updated the status code return values to those defined in the
       function description in the PI specification, Vol 1 v1.7.
    2. Updated the EFI_PEI_INSTALL_PEI_MEMORY function description
       in PiPeiCis.h.

 MdeModulePkg/Core/Pei/PeiMain.h               | 28 ++++++++++++++----
 MdeModulePkg/Core/Pei/Memory/MemoryServices.c | 30 ++++++++++++++------
 2 files changed, 43 insertions(+), 15 deletions(-)

diff --git a/MdeModulePkg/Core/Pei/PeiMain.h b/MdeModulePkg/Core/Pei/PeiMain.h
index f2aa97c664..0d3d62dbbe 100644
--- a/MdeModulePkg/Core/Pei/PeiMain.h
+++ b/MdeModulePkg/Core/Pei/PeiMain.h
@@ -898,15 +898,31 @@ InitializeMemoryServices (
   );
 
 /**
+  Registers the found memory configuration with the PEI Foundation.
 
-  Install the permanent memory is now available.
-  Creates HOB (PHIT and Stack).
+  This service enables PEIMs to register the permanent memory configuration that has been initialized
+  with the PEI Foundation. The result of this call-set is the creation of the appropriate Hand-Off Block
+  (HOB) describing the physical memory.
 
-  @param PeiServices     An indirect pointer to the EFI_PEI_SERVICES table published by the PEI Foundation.
-  @param MemoryBegin     Start of memory address.
-  @param MemoryLength    Length of memory.
+  The usage model is that the PEIM that discovers the permanent memory shall invoke this service.
+  This routine will store discovered memory information in the PeiCore's private data, and set the
+  SwitchStackSignal flag. After the PEIM who discovered memory is dispatched, the PeiDispatcher will
+  migrate temporary memory to permanent memory.
 
-  @return EFI_SUCCESS Always success.
+  The memory reported is a single contiguous run. It should be enough to allocate a PEI stack and
+  some HOB list. The full memory map will be reported using the appropriate memory HOBs. The
+  PEI Foundation will follow up with an installation of EFI_PEI_PERMANENT_MEMORY_INSTALLED_PPI.
+
+  Any invocations of this service after the first invocation which returns EFI_SUCCESS will be ignored.
+
+  @param[in] PeiServices     An indirect pointer to the EFI_PEI_SERVICES table published by the PEI Foundation.
+  @param[in] MemoryBegin     Start of memory address.
+  @param[in] MemoryLength    Length of memory.
+
+  @retval EFI_SUCCESS           The region was successfully installed in a HOB or this service was successfully
+                                invoked earlier and no HOB modification will occur.
+  @retval EFI_INVALID_PARAMETER MemoryBegin and MemoryLength are illegal for this system.
+  @retval EFI_OUT_OF_RESOURCES  There is no additional space for HOB creation.
 
 **/
 EFI_STATUS
diff --git a/MdeModulePkg/Core/Pei/Memory/MemoryServices.c b/MdeModulePkg/Core/Pei/Memory/MemoryServices.c
index 706837890f..679ac20493 100644
--- a/MdeModulePkg/Core/Pei/Memory/MemoryServices.c
+++ b/MdeModulePkg/Core/Pei/Memory/MemoryServices.c
@@ -1,7 +1,7 @@
 /** @file
   EFI PEI Core memory services
 
-Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -55,19 +55,31 @@ InitializeMemoryServices (
 }
 
 /**
+  Registers the found memory configuration with the PEI Foundation.
 
-  This function registers the found memory configuration with the PEI Foundation.
+  This service enables PEIMs to register the permanent memory configuration that has been initialized
+  with the PEI Foundation. The result of this call-set is the creation of the appropriate Hand-Off Block
+  (HOB) describing the physical memory.
 
   The usage model is that the PEIM that discovers the permanent memory shall invoke this service.
-  This routine will hold discoveried memory information into PeiCore's private data,
-  and set SwitchStackSignal flag. After PEIM who discovery memory is dispatched,
-  PeiDispatcher will migrate temporary memory to permenement memory.
+  This routine will store discovered memory information in the PeiCore's private data, and set the
+  SwitchStackSignal flag. After the PEIM who discovered memory is dispatched, the PeiDispatcher will
+  migrate temporary memory to permanent memory.
 
-  @param PeiServices        An indirect pointer to the EFI_PEI_SERVICES table published by the PEI Foundation.
-  @param MemoryBegin        Start of memory address.
-  @param MemoryLength       Length of memory.
+  The memory reported is a single contiguous run. It should be enough to allocate a PEI stack and
+  some HOB list. The full memory map will be reported using the appropriate memory HOBs. The
+  PEI Foundation will follow up with an installation of EFI_PEI_PERMANENT_MEMORY_INSTALLED_PPI.
 
-  @return EFI_SUCCESS Always success.
+  Any invocations of this service after the first invocation which returns EFI_SUCCESS will be ignored.
+
+  @param[in] PeiServices     An indirect pointer to the EFI_PEI_SERVICES table published by the PEI Foundation.
+  @param[in] MemoryBegin     Start of memory address.
+  @param[in] MemoryLength    Length of memory.
+
+  @retval EFI_SUCCESS           The region was successfully installed in a HOB or this service was successfully
+                                invoked earlier and no HOB modification will occur.
+  @retval EFI_INVALID_PARAMETER MemoryBegin and MemoryLength are illegal for this system.
+  @retval EFI_OUT_OF_RESOURCES  There is no additional space for HOB creation.
 
 **/
 EFI_STATUS
-- 
2.16.2.windows.1