[PATCH 1/1] EmbeddedPkg/AcpiLib: Add more helper functions

["Nhi Pham" <nhi@os.amperecomputing.com>]

This adds more helper functions that assist in calculating the checksum,
locating an ACPI table by signature, and updating an AML integer object.

Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Abner Chang <abner.chang@hpe.com>
Cc: Daniel Schaefer <daniel.schaefer@hpe.com>
Signed-off-by: Nhi Pham <nhi@os.amperecomputing.com>
---
 EmbeddedPkg/Library/AcpiLib/AcpiLib.inf |   2 +
 EmbeddedPkg/Include/Library/AcpiLib.h   |  68 ++++++++
 EmbeddedPkg/Library/AcpiLib/AcpiLib.c   | 183 ++++++++++++++++++++
 3 files changed, 253 insertions(+)

diff --git a/EmbeddedPkg/Library/AcpiLib/AcpiLib.inf b/EmbeddedPkg/Library/AcpiLib/AcpiLib.inf
index 538fe09cca29..154cb1eebc80 100644
--- a/EmbeddedPkg/Library/AcpiLib/AcpiLib.inf
+++ b/EmbeddedPkg/Library/AcpiLib/AcpiLib.inf
@@ -23,6 +23,8 @@ [Packages]
   EmbeddedPkg/EmbeddedPkg.dec
 
 [LibraryClasses]
+  BaseLib
+  BaseMemoryLib
   DebugLib
   UefiBootServicesTableLib
 
diff --git a/EmbeddedPkg/Include/Library/AcpiLib.h b/EmbeddedPkg/Include/Library/AcpiLib.h
index c142446d9d59..cdb6ea410c54 100644
--- a/EmbeddedPkg/Include/Library/AcpiLib.h
+++ b/EmbeddedPkg/Include/Library/AcpiLib.h
@@ -13,6 +13,7 @@
 #include <Uefi.h>
 
 #include <IndustryStandard/Acpi10.h>
+#include <Protocol/AcpiSystemDescriptionTable.h>
 
 //
 // Macros for the Generic Address Space
@@ -128,4 +129,71 @@ LocateAndInstallAcpiFromFv (
   IN CONST EFI_GUID* AcpiFile
   );
 
+/**
+  This function calculates and updates an UINT8 checksum.
+
+  @param  Buffer          Pointer to buffer to checksum
+  @param  Size            Number of bytes to checksum
+
+  @retval EFI_SUCCESS             The function completed successfully.
+  @retval EFI_INVALID_PARAMETER   Invalid parameter.
+
+**/
+EFI_STATUS
+EFIAPI
+AcpiUpdateChecksum (
+  IN UINT8      *Buffer,
+  IN UINTN      Size
+  );
+
+/**
+  This function uses the ACPI SDT protocol to locate an ACPI table
+  with a given signature that only have a single instance.
+
+  Caution: This function does not act correctly with tables having
+  more than 2 instances like SSDT table.
+
+  @param  AcpiTableSdtProtocol    Pointer to ACPI SDT protocol.
+  @param  TableSignature          ACPI table signature.
+  @param  Table                   Pointer to the table.
+  @param  TableKey                Pointer to the table key.
+
+  @return EFI_SUCCESS             The function completed successfully.
+  @return EFI_INVALID_PARAMETER   At least one of parameters is invalid.
+  @retval EFI_NOT_FOUND           The requested index is too large and a table was not found.
+
+**/
+EFI_STATUS
+EFIAPI
+AcpiLocateTableBySignature (
+  IN  EFI_ACPI_SDT_PROTOCOL           *AcpiSdtProtocol,
+  IN  UINT32                          TableSignature,
+  OUT EFI_ACPI_DESCRIPTION_HEADER     **Table,
+  OUT UINTN                           *TableKey
+  );
+
+/**
+  This function updates the integer value of an AML Object.
+
+  @param  AcpiTableSdtProtocol    Pointer to ACPI SDT protocol.
+  @param  TableHandle             Points to the table representing the starting point
+                                  for the object path search.
+  @param  AsciiObjectPath         Pointer to the ACPI path of the object being updated.
+  @param  Value                   New value to write to the object.
+
+  @return EFI_SUCCESS             The function completed successfully.
+  @return EFI_INVALID_PARAMETER   At least one of parameters is invalid or the data type
+                                  of the ACPI object is not an integer value.
+  @retval EFI_NOT_FOUND           The object is not found with the given path.
+
+**/
+EFI_STATUS
+EFIAPI
+AcpiAmlObjectUpdateInteger (
+  IN  EFI_ACPI_SDT_PROTOCOL           *AcpiSdtProtocol,
+  IN  EFI_ACPI_HANDLE                 TableHandle,
+  IN  CHAR8                           *AsciiObjectPath,
+  IN  UINTN                           Value
+  );
+
 #endif // __ACPI_LIB_H__
diff --git a/EmbeddedPkg/Library/AcpiLib/AcpiLib.c b/EmbeddedPkg/Library/AcpiLib/AcpiLib.c
index ff7d678433d5..e07919ae323f 100644
--- a/EmbeddedPkg/Library/AcpiLib/AcpiLib.c
+++ b/EmbeddedPkg/Library/AcpiLib/AcpiLib.c
@@ -9,9 +9,12 @@
 #include <Uefi.h>
 
 #include <Library/AcpiLib.h>
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
 #include <Library/DebugLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 
+#include <Protocol/AcpiSystemDescriptionTable.h>
 #include <Protocol/AcpiTable.h>
 #include <Protocol/FirmwareVolume2.h>
 
@@ -170,3 +173,183 @@ LocateAndInstallAcpiFromFv (
 {
   return LocateAndInstallAcpiFromFvConditional (AcpiFile, NULL);
 }
+
+/**
+  This function calculates and updates an UINT8 checksum.
+
+  @param  Buffer          Pointer to buffer to checksum
+  @param  Size            Number of bytes to checksum
+
+  @retval EFI_SUCCESS             The function completed successfully.
+  @retval EFI_INVALID_PARAMETER   Invalid parameter.
+
+**/
+EFI_STATUS
+EFIAPI
+AcpiUpdateChecksum (
+  IN UINT8      *Buffer,
+  IN UINTN      Size
+  )
+{
+  UINTN ChecksumOffset;
+
+  if (Buffer == NULL || Size == 0) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  ChecksumOffset = OFFSET_OF (EFI_ACPI_DESCRIPTION_HEADER, Checksum);
+
+  //
+  // Set checksum to 0 first
+  //
+  Buffer[ChecksumOffset] = 0;
+
+  //
+  // Update checksum value
+  //
+  Buffer[ChecksumOffset] = CalculateCheckSum8 (Buffer, Size);
+
+  return EFI_SUCCESS;
+}
+
+/**
+  This function uses the ACPI SDT protocol to locate an ACPI table
+  with a given signature that only have a single instance.
+
+  Caution: This function does not act correctly with tables having
+  more than 2 instances like SSDT table.
+
+  @param  AcpiTableSdtProtocol    Pointer to ACPI SDT protocol.
+  @param  TableSignature          ACPI table signature.
+  @param  Table                   Pointer to the table.
+  @param  TableKey                Pointer to the table key.
+
+  @return EFI_SUCCESS             The function completed successfully.
+  @return EFI_INVALID_PARAMETER   At least one of parameters is invalid.
+  @retval EFI_NOT_FOUND           The requested index is too large and a table was not found.
+
+**/
+EFI_STATUS
+EFIAPI
+AcpiLocateTableBySignature (
+  IN  EFI_ACPI_SDT_PROTOCOL           *AcpiSdtProtocol,
+  IN  UINT32                          TableSignature,
+  OUT EFI_ACPI_DESCRIPTION_HEADER     **Table,
+  OUT UINTN                           *TableKey
+  )
+{
+  EFI_STATUS              Status;
+  EFI_ACPI_SDT_HEADER     *TempTable;
+  EFI_ACPI_TABLE_VERSION  TableVersion;
+  UINTN                   TableIndex;
+
+  if (AcpiSdtProtocol == NULL
+      || Table == NULL
+      || TableKey == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  Status = EFI_SUCCESS;
+
+  //
+  // Search for ACPI Table with matching signature
+  //
+  TableVersion = 0;
+  TableIndex = 0;
+  while (!EFI_ERROR (Status)) {
+    Status = AcpiSdtProtocol->GetAcpiTable (
+                                TableIndex,
+                                &TempTable,
+                                &TableVersion,
+                                TableKey
+                                );
+    if (!EFI_ERROR (Status)) {
+      TableIndex++;
+
+      if (((EFI_ACPI_DESCRIPTION_HEADER *)TempTable)->Signature == TableSignature) {
+        *Table = (EFI_ACPI_DESCRIPTION_HEADER *)TempTable;
+        break;
+      }
+    }
+  }
+
+  return Status;
+}
+
+/**
+  This function updates the integer value of an AML Object.
+
+  @param  AcpiTableSdtProtocol    Pointer to ACPI SDT protocol.
+  @param  TableHandle             Points to the table representing the starting point
+                                  for the object path search.
+  @param  AsciiObjectPath         Pointer to the ACPI path of the object being updated.
+  @param  Value                   New value to write to the object.
+
+  @return EFI_SUCCESS             The function completed successfully.
+  @return EFI_INVALID_PARAMETER   At least one of parameters is invalid or the data type
+                                  of the ACPI object is not an integer value.
+  @retval EFI_NOT_FOUND           The object is not found with the given path.
+
+**/
+EFI_STATUS
+EFIAPI
+AcpiAmlObjectUpdateInteger (
+  IN  EFI_ACPI_SDT_PROTOCOL           *AcpiSdtProtocol,
+  IN  EFI_ACPI_HANDLE                 TableHandle,
+  IN  CHAR8                           *AsciiObjectPath,
+  IN  UINTN                           Value
+  )
+{
+  EFI_STATUS            Status;
+  EFI_ACPI_HANDLE       ObjectHandle;
+  EFI_ACPI_DATA_TYPE    DataType;
+  UINT8                 *Buffer;
+  UINTN                 BufferSize;
+
+  if (AcpiSdtProtocol == NULL || AsciiObjectPath == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  Status = AcpiSdtProtocol->FindPath (TableHandle, AsciiObjectPath, &ObjectHandle);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Status = AcpiSdtProtocol->GetOption (ObjectHandle, 0, &DataType, (VOID *)&Buffer, &BufferSize);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  if (Buffer[0] != AML_NAME_OP) {
+    return EFI_NOT_FOUND;
+  }
+
+  switch (Buffer[5]) {
+  case AML_ZERO_OP:
+  case AML_ONE_OP:
+    Buffer[5] = (UINT8)Value;
+    break;
+
+  case AML_BYTE_PREFIX:
+    Buffer[6] = (UINT8)Value;
+    break;
+
+  case AML_WORD_PREFIX:
+    CopyMem ((VOID *)&Buffer[6], (VOID *)&Buffer, sizeof (UINT16));
+    break;
+
+  case AML_DWORD_PREFIX:
+    CopyMem ((VOID *)&Buffer[6], (VOID *)&Buffer, sizeof (UINT32));
+    break;
+
+  case AML_QWORD_PREFIX:
+    CopyMem ((VOID *)&Buffer[6], (VOID *)&Buffer, sizeof (UINT64));
+    break;
+
+  default:
+    // The data type of the ACPI object is not an integer value.
+    return EFI_INVALID_PARAMETER;
+  }
+
+  return Status;
+}
-- 
2.17.1