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Code: Select all

  NfitLen = sizeof(EFI_ACPI_6_1_NVDIMM_FIRMWARE_INTERFACE_TABLE) +
            sizeof(EFI_ACPI_6_1_NFIT_SYSTEM_PHYSICAL_ADDRESS_RANGE_STRUCTURE);
  Nfit = AllocateZeroPool(NfitLen);
  if (NULL == Nfit)
    return EFI_OUT_OF_RESOURCES;

  SpaRange = (EFI_ACPI_6_1_NFIT_SYSTEM_PHYSICAL_ADDRESS_RANGE_STRUCTURE *)
              ((UINT8 *)Nfit + sizeof(EFI_ACPI_6_1_NVDIMM_FIRMWARE_INTERFACE_TABLE));

  /* OEM ID shouldn't matter or need to be recognized. */
  UINT8 PcdAcpiDefaultOemId[6] = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06 };

  NfitHeader                  = (EFI_ACPI_DESCRIPTION_HEADER *)Nfit;
  NfitHeader->Signature       = EFI_ACPI_6_1_NVDIMM_FIRMWARE_INTERFACE_TABLE_STRUCTURE_SIGNATURE;
  NfitHeader->Length          = NfitLen;
  NfitHeader->Revision        = EFI_ACPI_6_1_NVDIMM_FIRMWARE_INTERFACE_TABLE_REVISION;
  NfitHeader->OemRevision     = 0x20240501;   /* OEM Revision by date should be fine. */
  NfitHeader->CreatorId       = EFI_SIGNATURE_32('T', 'T', 'O', 'O');   /* Creator: 'TTOO' */
  NfitHeader->CreatorRevision = 0x1;   /* Should just be 1. */
  NfitHeader->OemTableId      = EFI_SIGNATURE_64('T', 'T', 'O', 'O', 'L', 'O', 'A', 'D');
  CopyMem(NfitHeader->OemId, &PcdAcpiDefaultOemId[0], sizeof(NfitHeader->OemId));

  /* Fill in the content of the SPA Range Structure. */
  SpaRange->Type                             = EFI_ACPI_6_1_NFIT_SYSTEM_PHYSICAL_ADDRESS_RANGE_STRUCTURE_TYPE;
  SpaRange->Length                           = sizeof (EFI_ACPI_6_1_NFIT_SYSTEM_PHYSICAL_ADDRESS_RANGE_STRUCTURE);
  SpaRange->SystemPhysicalAddressRangeBase   = PrivateData->StartingAddr;
  SpaRange->SystemPhysicalAddressRangeLength = PrivateData->Size;
  CopyMem(&SpaRange->AddressRangeTypeGUID, &PrivateData->TypeGuid, sizeof(EFI_GUID));

  Checksum             = CalculateCheckSum8((UINT8 *)Nfit, NfitHeader->Length);
  NfitHeader->Checksum = Checksum;

  /*
   * Publish the NFIT to the ACPI table.
   * Note, since the NFIT might be modified by other driver, therefore, we
   * do not track the returning TableKey from the InstallAcpiTable().
   */
  Status = uefi_call_wrapper(
    mAcpiTableProtocol->InstallAcpiTable,
    4,
    mAcpiTableProtocol,
    Nfit,
    NfitHeader->Length,
    &TableKey
  );
  if (EFI_ERROR(Status))
    return Status;

  FreePool(Nfit);
  return EFI_SUCCESS;

Code: Select all

DefinitionBlock (
  "RamDisk.aml",
  "SSDT",
  2,
  "TTOOLD",
  "RamDisk ",
  0x1000
  )
{
  Scope (\_SB)
  {
    Device (NVDR)
    {
      Name (_HID, "ACPI0012")
      Name (_STR, Unicode("NVDIMM Root Device"))

      Method (_STA, 0)
      {
        Return (0x0f)
      }
    }
  }
}

Code: Select all

static
EFI_STATUS
RamDiskPublishSsdt()
{
  EFI_STATUS Status;

  /* [Debug logging info...] */

  /*
   * Install an SSDT entry for the ACPI table using some compiled AML.
   *   The AML comes from the RamDisk.asl file in the local folder.
   *   This is compiled on Linux using the 'iasl' tool and the resultant
   *   bytecode is placed in a static C variable.
   * 
   * Compilation Command/Macro:
   *    iasl RamDisk.asl && echo && \
   *       T="$(xxd -p RamDisk.aml | tr -d '\n' | sed -r 's/(..)/0x\1, /g')" && echo && \
   *       echo "$T" | sed -r "s/((0x..,\s){8})/\1\r\n/g"
   * 
   * This code assumes that the "RamDisk " SSDT is NOT already installed at boot.
   */
  Status = uefi_call_wrapper(
    mAcpiTableProtocol->InstallAcpiTable,
    4,
    mAcpiTableProtocol,
    gNvdimmAml,
    gNvdimmAmlLength,
    &mAcpiNvdimmTableKey
  );
  return Status;
}

Code: Select all

static
EFI_STATUS
RamDiskPublishNfit(
  IN RAM_DISK_PRIVATE_DATA *PrivateData)
{
  /* ... ... ... */

  /* All data structure definitions use the ACPI specification, except RAM_DISK_PRIVATE_DATA. */
  /* See: https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/05_ACPI_Software_Programming_Model/ACPI_Software_Programming_Model.html#nvdimm-firmware-interface-table-nfit */

  Status = RamDiskPublishSsdt();   /* Publish NVDIMM Root Device first; check Status. */
  /* ... */

  /* In this (very specific) scenario, the NFIT will consist of its own entry, with an SPA stub to represent the virtual ramdisk. */
  UINT32 NfitLen = sizeof(EFI_ACPI_6_4_NVDIMM_FIRMWARE_INTERFACE_TABLE) +
            sizeof(EFI_ACPI_6_4_NFIT_SYSTEM_PHYSICAL_ADDRESS_RANGE_STRUCTURE);
  VOID *Nfit = AllocateZeroPool(NfitLen);
  if (NULL == Nfit)
    return EFI_OUT_OF_RESOURCES;

  EFI_ACPI_6_4_NFIT_SYSTEM_PHYSICAL_ADDRESS_RANGE_STRUCTURE *SpaRange =
              (EFI_ACPI_6_4_NFIT_SYSTEM_PHYSICAL_ADDRESS_RANGE_STRUCTURE *)
              ((UINT8 *)Nfit + sizeof(EFI_ACPI_6_4_NVDIMM_FIRMWARE_INTERFACE_TABLE));

  UINT8 DefaultOemId[6] = /* An array of 6 ASCII characters. */ ;

  EFI_ACPI_DESCRIPTION_HEADER *NfitHeader;
  NfitHeader                  = (EFI_ACPI_DESCRIPTION_HEADER *)Nfit;
  NfitHeader->Signature       = EFI_ACPI_6_4_NVDIMM_FIRMWARE_INTERFACE_TABLE_STRUCTURE_SIGNATURE;
  NfitHeader->Length          = NfitLen;
  NfitHeader->Revision        = EFI_ACPI_6_4_NVDIMM_FIRMWARE_INTERFACE_TABLE_REVISION;
  NfitHeader->OemRevision     = MY_PERSONAL_OEM_REVISION_ID;
  NfitHeader->CreatorId       = EFI_SIGNATURE_32(/* ... */);   /* Creator: '...' */
  NfitHeader->CreatorRevision = MY_CREATOR_REVISION_NUMBER;
  NfitHeader->OemTableId      = EFI_SIGNATURE_64(/* ... */);
  CopyMem(NfitHeader->OemId, &DefaultOemId[0], sizeof(NfitHeader->OemId));

  /* Populate the SPA for the virtual disk. */
  SpaRange->Type                             = EFI_ACPI_6_4_NFIT_SYSTEM_PHYSICAL_ADDRESS_RANGE_STRUCTURE_TYPE;
  SpaRange->Length                           = sizeof(EFI_ACPI_6_4_NFIT_SYSTEM_PHYSICAL_ADDRESS_RANGE_STRUCTURE);
  SpaRange->SystemPhysicalAddressRangeBase   = PrivateData->StartingAddr;
  SpaRange->SystemPhysicalAddressRangeLength = PrivateData->Size;
  CopyMem(&SpaRange->AddressRangeTypeGUID, &PrivateData->TypeGuid, sizeof(EFI_GUID));

  /* Table checksum, now that it's completely filled out. */
  NfitHeader->Checksum = CalculateCheckSum8((UINT8 *)Nfit, NfitHeader->Length);

  /* Publish the NFIT to the ACPI table. */
  Status = uefi_call_wrapper(
    mAcpiTableProtocol->InstallAcpiTable,
    4,
    mAcpiTableProtocol,
    Nfit,
    NfitHeader->Length,
    &TableKey
  );
}