[PATCH 2/6] IntelSiliconPkg IntelVTdDxe: Use new EfiFindAcpiTableBySignature()

[Star Zeng <star.zeng@intel.com>]

https://bugzilla.tianocore.org/show_bug.cgi?id=967
Request to add a library function for GetAcpiTable() in order
to get ACPI table using signature as input.

After evaluation, we found there are many duplicated code to
find ACPI table by signature in different modules.

This patch updates IntelVTdDxe to use new
EfiFindAcpiTableBySignature() and remove the duplicated code.

Cc: Younas khan <pmdyounaskhan786@gmail.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Star Zeng <star.zeng@intel.com>
---
 .../Feature/VTd/IntelVTdDxe/DmarAcpiTable.c        | 136 +--------------------
 1 file changed, 3 insertions(+), 133 deletions(-)

diff --git a/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c b/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
index 24723fe4972a..1e8c1f620c98 100644
--- a/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
+++ b/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
@@ -868,116 +868,6 @@ ParseDmarAcpiTableRmrr (
 }
 
 /**
-  This function scan ACPI table in RSDT.
-
-  @param[in]  Rsdt      ACPI RSDT
-  @param[in]  Signature ACPI table signature
-
-  @return ACPI table
-**/
-VOID *
-ScanTableInRSDT (
-  IN RSDT_TABLE                   *Rsdt,
-  IN UINT32                       Signature
-  )
-{
-  UINTN                         Index;
-  UINT32                        EntryCount;
-  UINT32                        *EntryPtr;
-  EFI_ACPI_DESCRIPTION_HEADER   *Table;
-
-  EntryCount = (Rsdt->Header.Length - sizeof (EFI_ACPI_DESCRIPTION_HEADER)) / sizeof(UINT32);
-
-  EntryPtr = &Rsdt->Entry;
-  for (Index = 0; Index < EntryCount; Index ++, EntryPtr ++) {
-    Table = (EFI_ACPI_DESCRIPTION_HEADER*)((UINTN)(*EntryPtr));
-    if ((Table != NULL) && (Table->Signature == Signature)) {
-      return Table;
-    }
-  }
-
-  return NULL;
-}
-
-/**
-  This function scan ACPI table in XSDT.
-
-  @param[in]  Xsdt      ACPI XSDT
-  @param[in]  Signature ACPI table signature
-
-  @return ACPI table
-**/
-VOID *
-ScanTableInXSDT (
-  IN XSDT_TABLE                   *Xsdt,
-  IN UINT32                       Signature
-  )
-{
-  UINTN                        Index;
-  UINT32                       EntryCount;
-  UINT64                       EntryPtr;
-  UINTN                        BasePtr;
-  EFI_ACPI_DESCRIPTION_HEADER  *Table;
-
-  EntryCount = (Xsdt->Header.Length - sizeof (EFI_ACPI_DESCRIPTION_HEADER)) / sizeof(UINT64);
-
-  BasePtr = (UINTN)(&(Xsdt->Entry));
-  for (Index = 0; Index < EntryCount; Index ++) {
-    CopyMem (&EntryPtr, (VOID *)(BasePtr + Index * sizeof(UINT64)), sizeof(UINT64));
-    Table = (EFI_ACPI_DESCRIPTION_HEADER*)((UINTN)(EntryPtr));
-    if ((Table != NULL) && (Table->Signature == Signature)) {
-      return Table;
-    }
-  }
-
-  return NULL;
-}
-
-/**
-  This function scan ACPI table in RSDP.
-
-  @param[in]  Rsdp      ACPI RSDP
-  @param[in]  Signature ACPI table signature
-
-  @return ACPI table
-**/
-VOID *
-FindAcpiPtr (
-  IN EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER *Rsdp,
-  IN UINT32                                       Signature
-  )
-{
-  EFI_ACPI_DESCRIPTION_HEADER                    *AcpiTable;
-  RSDT_TABLE                                     *Rsdt;
-  XSDT_TABLE                                     *Xsdt;
-
-  AcpiTable = NULL;
-
-  //
-  // Check ACPI2.0 table
-  //
-  Rsdt = (RSDT_TABLE *)(UINTN)Rsdp->RsdtAddress;
-  Xsdt = NULL;
-  if ((Rsdp->Revision >= 2) && (Rsdp->XsdtAddress < (UINT64)(UINTN)-1)) {
-    Xsdt = (XSDT_TABLE *)(UINTN)Rsdp->XsdtAddress;
-  }
-  //
-  // Check Xsdt
-  //
-  if (Xsdt != NULL) {
-    AcpiTable = ScanTableInXSDT (Xsdt, Signature);
-  }
-  //
-  // Check Rsdt
-  //
-  if ((AcpiTable == NULL) && (Rsdt != NULL)) {
-    AcpiTable = ScanTableInRSDT (Rsdt, Signature);
-  }
-
-  return AcpiTable;
-}
-
-/**
   Get the DMAR ACPI table.
 
   @retval EFI_SUCCESS           The DMAR ACPI table is got.
@@ -989,33 +879,13 @@ GetDmarAcpiTable (
   VOID
   )
 {
-  VOID                              *AcpiTable;
-  EFI_STATUS                        Status;
-
   if (mAcpiDmarTable != NULL) {
     return EFI_ALREADY_STARTED;
   }
 
-  AcpiTable = NULL;
-  Status = EfiGetSystemConfigurationTable (
-             &gEfiAcpi20TableGuid,
-             &AcpiTable
-             );
-  if (EFI_ERROR (Status)) {
-    Status = EfiGetSystemConfigurationTable (
-               &gEfiAcpi10TableGuid,
-               &AcpiTable
-               );
-  }
-  if (EFI_ERROR (Status)) {
-    return EFI_NOT_FOUND;
-  }
-  ASSERT (AcpiTable != NULL);
-
-  mAcpiDmarTable = FindAcpiPtr (
-                      (EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER *)AcpiTable,
-                      EFI_ACPI_4_0_DMA_REMAPPING_TABLE_SIGNATURE
-                      );
+  mAcpiDmarTable = (EFI_ACPI_DMAR_HEADER *) EfiFindAcpiTableBySignature (
+                                              EFI_ACPI_4_0_DMA_REMAPPING_TABLE_SIGNATURE
+                                              );
   if (mAcpiDmarTable == NULL) {
     return EFI_NOT_FOUND;
   }
-- 
2.7.0.windows.1