[edk2-platforms][PATCH V2 03/16] Platform/Loongson: Add PeiServicesTablePointerLib.

["xianglai" <lixianglai@loongson.cn>]

Use a register to save PeiServicesTable pointer,
This lib Provides PeiServicesTable pointer saving
and retrieval services.

Signed-off-by: xianglai li <lixianglai@loongson.cn>
---
 .../PeiServicesTablePointer.c                 | 78 +++++++++++++++++++
 .../PeiServicesTablePointerLib.inf            | 32 ++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 Platform/Loongson/LoongArchQemuPkg/Library/PeiServicesTablePointerLib/PeiServicesTablePointer.c
 create mode 100644 Platform/Loongson/LoongArchQemuPkg/Library/PeiServicesTablePointerLib/PeiServicesTablePointerLib.inf

diff --git a/Platform/Loongson/LoongArchQemuPkg/Library/PeiServicesTablePointerLib/PeiServicesTablePointer.c b/Platform/Loongson/LoongArchQemuPkg/Library/PeiServicesTablePointerLib/PeiServicesTablePointer.c
new file mode 100644
index 0000000000..068960d4ce
--- /dev/null
+++ b/Platform/Loongson/LoongArchQemuPkg/Library/PeiServicesTablePointerLib/PeiServicesTablePointer.c
@@ -0,0 +1,78 @@
+/** @file
+  PEI Services Table Pointer Library.
+
+  Copyright (c) 2021 Loongson Technology Corporation Limited. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <PiPei.h>
+#include <Library/PeiServicesTablePointerLib.h>
+#include <Library/DebugLib.h>
+#include "Library/Cpu.h"
+
+/**
+  Caches a pointer PEI Services Table.
+
+  Caches the pointer to the PEI Services Table specified by PeiServicesTablePointer
+  in a platform specific manner.
+
+  If PeiServicesTablePointer is NULL, then ASSERT ().
+
+  @param    PeiServicesTablePointer   The address of PeiServices pointer.
+**/
+VOID
+EFIAPI
+SetPeiServicesTablePointer (
+  IN CONST EFI_PEI_SERVICES ** PeiServicesTablePointer
+  )
+{
+  LOONGARCH_CSR_WRITEQ ((UINTN)PeiServicesTablePointer, LOONGARCH_CSR_KS0);
+}
+
+/**
+  Retrieves the cached value of the PEI Services Table pointer.
+
+  Returns the cached value of the PEI Services Table pointer in a CPU specific manner
+  as specified in the CPU binding section of the Platform Initialization Pre-EFI
+  Initialization Core Interface Specification.
+
+  If the cached PEI Services Table pointer is NULL, then ASSERT ().
+
+  @return  The pointer to PeiServices.
+**/
+CONST EFI_PEI_SERVICES **
+EFIAPI
+GetPeiServicesTablePointer (
+  VOID
+  )
+{
+  UINTN  val;
+
+  LOONGARCH_CSR_READQ (val, LOONGARCH_CSR_KS0);
+  return (CONST EFI_PEI_SERVICES **)val;
+}
+
+/**
+Perform CPU specific actions required to migrate the PEI Services Table
+pointer from temporary RAM to permanent RAM.
+
+For IA32 CPUs, the PEI Services Table pointer is stored in the 4 bytes
+immediately preceding the Interrupt Descriptor Table (IDT) in memory.
+For X64 CPUs, the PEI Services Table pointer is stored in the 8 bytes
+immediately preceding the Interrupt Descriptor Table (IDT) in memory.
+For Itanium and ARM CPUs, a the PEI Services Table Pointer is stored in
+a dedicated CPU register.  This means that there is no memory storage
+associated with storing the PEI Services Table pointer, so no additional
+migration actions are required for Itanium or ARM CPUs.
+
+**/
+VOID
+EFIAPI
+MigratePeiServicesTablePointer (
+VOID
+)
+{
+  return;
+}
diff --git a/Platform/Loongson/LoongArchQemuPkg/Library/PeiServicesTablePointerLib/PeiServicesTablePointerLib.inf b/Platform/Loongson/LoongArchQemuPkg/Library/PeiServicesTablePointerLib/PeiServicesTablePointerLib.inf
new file mode 100644
index 0000000000..6fe76d1351
--- /dev/null
+++ b/Platform/Loongson/LoongArchQemuPkg/Library/PeiServicesTablePointerLib/PeiServicesTablePointerLib.inf
@@ -0,0 +1,32 @@
+## @file
+#  PEI Services Table Pointer Library.
+#
+#  Copyright (c) 2021 Loongson Technology Corporation Limited. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = PeiServicesTablePointerLib
+  FILE_GUID                      = C3C9C4ED-EB8A-4548-BE1B-ABB0B6F35B1E
+  MODULE_TYPE                    = PEIM
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = PeiServicesTablePointerLib|PEIM PEI_CORE SEC
+
+#
+#  VALID_ARCHITECTURES           = LOONGARCH64
+#
+
+[Sources]
+  PeiServicesTablePointer.c
+
+[Packages]
+  Platform/Loongson/LoongArchQemuPkg/Loongson.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  DebugLib
+
+[Pcd]
+
-- 
2.31.1