[PATCH edk2-platforms v1 1/2] Drivers/OpTeeRpmb: Add an OP-TEE backed RPMB driver

["Sughosh Ganu" <sughosh.ganu@linaro.org>]

From: Ilias Apalodimas <ilias.apalodimas@linaro.org>

A following patch is adding support for building StMM in order to run it
from OP-TEE.
OP-TEE in combination with a NS-world supplicant can use the RPMB
partition of an eMMC to store EFI variables. The supplicant
functionality is currently available in U-Boot only but can be ported
into EDK2. Assuming similar functionality is added in EDK2, this will
allow any hardware with an RPMB partition to store EFI variables
securely.

So let's add a driver that enables access of the RPMB partition through
OP-TEE. Since the upper layers expect a byte addressable interface,
the driver allocates memory and patches the PCDs, while syncing the
memory/hardware on read/write callbacks.

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
---
 Drivers/OpTeeRpmb/FixupPcd.inf    |  44 ++
 Drivers/OpTeeRpmb/OpTeeRpmbFv.inf |  58 ++
 Drivers/OpTeeRpmb/OpTeeRpmbFvb.h  |  52 ++
 Drivers/OpTeeRpmb/FixupPcd.c      |  74 ++
 Drivers/OpTeeRpmb/OpTeeRpmbFvb.c  | 775 ++++++++++++++++++++
 5 files changed, 1003 insertions(+)

diff --git a/Drivers/OpTeeRpmb/FixupPcd.inf b/Drivers/OpTeeRpmb/FixupPcd.inf
new file mode 100644
index 0000000000..f0cfdf7a4c
--- /dev/null
+++ b/Drivers/OpTeeRpmb/FixupPcd.inf
@@ -0,0 +1,44 @@
+## @file
+#  Instance of Base Memory Library without assembly.
+#
+#  Copyright (c) 2020, Linaro Ltd. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001A
+  BASE_NAME                      = FixupPcd
+  FILE_GUID                      = a827c337-a9c6-301b-aeb7-acbc95d8da22
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 0.1
+  LIBRARY_CLASS                  = RpmbPcdFixup|MM_STANDALONE
+  CONSTRUCTOR                    = FixPcdMemory
+
+[Sources]
+  FixupPcd.c
+  OpTeeRpmbFvb.h
+
+[Packages]
+  MdeModulePkg/MdeModulePkg.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  MmServicesTableLib
+  PcdLib
+
+[Pcd]
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingBase
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingSize
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareBase
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareSize
+
+
+[Protocols]
+  gEfiSmmFirmwareVolumeBlockProtocolGuid          ## CONSUMES
diff --git a/Drivers/OpTeeRpmb/OpTeeRpmbFv.inf b/Drivers/OpTeeRpmb/OpTeeRpmbFv.inf
new file mode 100644
index 0000000000..b21f7397e5
--- /dev/null
+++ b/Drivers/OpTeeRpmb/OpTeeRpmbFv.inf
@@ -0,0 +1,58 @@
+## @file
+#
+#  Component description file for OpTeeRpmbFv module
+#
+#  Copyright (c) 2020, Linaro Ltd. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001A
+  BASE_NAME                      = OpTeeRpmbFv
+  FILE_GUID                      = 4803FC20-E583-3BCD-8C60-141E85C9A2CF
+  MODULE_TYPE                    = MM_STANDALONE
+  VERSION_STRING                 = 0.1
+  PI_SPECIFICATION_VERSION       = 0x00010032
+  ENTRY_POINT                    = OpTeeRpmbFvbInit
+
+[Sources]
+  OpTeeRpmbFvb.c
+  OpTeeRpmbFvb.h
+
+[Packages]
+  ArmPkg/ArmPkg.dec
+  ArmPlatformPkg/ArmPlatformPkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+  MdePkg/MdePkg.dec
+  StandaloneMmPkg/StandaloneMmPkg.dec
+
+[LibraryClasses]
+  ArmSvcLib
+  BaseLib
+  BaseMemoryLib
+  DebugLib
+  MemoryAllocationLib
+  MmServicesTableLib
+  PcdLib
+  StandaloneMmDriverEntryPoint
+
+[Guids]
+  gEfiAuthenticatedVariableGuid
+  gEfiSystemNvDataFvGuid
+  gEfiVariableGuid
+
+[Pcd]
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingBase
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingSize
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareBase
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareSize
+
+[Protocols]
+  gEfiSmmFirmwareVolumeBlockProtocolGuid          ## PRODUCES
+
+[Depex]
+  TRUE
diff --git a/Drivers/OpTeeRpmb/OpTeeRpmbFvb.h b/Drivers/OpTeeRpmb/OpTeeRpmbFvb.h
new file mode 100644
index 0000000000..f6c3fe2639
--- /dev/null
+++ b/Drivers/OpTeeRpmb/OpTeeRpmbFvb.h
@@ -0,0 +1,52 @@
+/** @file
+
+  Copyright (c) 2020, Linaro Ltd. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef __OPTEE_RPMB_FV_
+#define __OPTEE_RPMB_FV_
+
+/* SVC Args */
+#define SP_SVC_RPMB_READ                0xC4000066
+#define SP_SVC_RPMB_WRITE               0xC4000067
+#define SP_SVC_GET_UART                 0xC4000068
+
+#define FILENAME "EFI_VARS"
+
+#define NBLOCKS                    (3 * 16) // EFI Vars, FTW working, FTW spare
+#define BLOCK_SIZE                 SIZE_4KB
+#define FLASH_SIGNATURE            SIGNATURE_32('r', 'p', 'm', 'b')
+#define INSTANCE_FROM_FVB_THIS(a)  CR(a, MEM_INSTANCE, FvbProtocol, \
+                                      FLASH_SIGNATURE)
+enum _RPMB_FILE_MAP {
+  EFI_VARS,
+  FTW_WORK,
+  FTW_SPARE,
+};
+
+typedef enum _RPMB_FILE_MAP RPMB_FILE_MAP;
+
+struct _MAP_VAL_TO_FILE {
+  CHAR8         *Filename;
+  RPMB_FILE_MAP Map;
+};
+
+typedef struct _MAP_VAL_TO_FILE MAP_VAL_TO_FILE;
+
+typedef struct _MEM_INSTANCE         MEM_INSTANCE;
+typedef EFI_STATUS (*MEM_INITIALIZE) (MEM_INSTANCE* Instance);
+struct _MEM_INSTANCE
+{
+    UINT32                              Signature;
+    MEM_INITIALIZE                      Initialize;
+    BOOLEAN                             Initialized;
+    EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  FvbProtocol;
+    EFI_HANDLE                          Handle;
+    EFI_PHYSICAL_ADDRESS                MemBaseAddress;
+    UINT16                              BlockSize;
+    UINT16                              NBlocks;
+};
+
+#endif
diff --git a/Drivers/OpTeeRpmb/FixupPcd.c b/Drivers/OpTeeRpmb/FixupPcd.c
new file mode 100644
index 0000000000..3cc882fa94
--- /dev/null
+++ b/Drivers/OpTeeRpmb/FixupPcd.c
@@ -0,0 +1,74 @@
+/** @file
+
+  Update the patched PCDs to their correct value
+
+  Copyright (c) 2020, Linaro Ltd. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+/**
+ * Patch the relevant PCDs of the RPMB driver with the correct address of the
+ * allocated memory
+ *
+**/
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/MmServicesTableLib.h>
+#include <Library/PcdLib.h>
+
+#include <Protocol/FirmwareVolumeBlock.h>
+#include <Protocol/SmmFirmwareVolumeBlock.h>
+
+#include "OpTeeRpmbFvb.h"
+
+/**
+  Fixup the Pcd values for variable storage
+
+  Since the upper layers of EDK2 expect a memory mapped interface and we can't
+  offer that from an RPMB, the driver allocates memory on init and passes that
+  on the upper layers. Since the memory is dynamically allocated and we can't set the
+  PCD is StMM context, we need to patch it correctly on each access
+
+  @retval EFI_SUCCESS Protocol was found and PCDs patched up
+
+ **/
+EFI_STATUS
+EFIAPI
+FixPcdMemory (
+  VOID
+  )
+{
+  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *FvbProtocol;
+  MEM_INSTANCE                        *Instance;
+  EFI_STATUS                          Status;
+
+  //
+  // Locate SmmFirmwareVolumeBlockProtocol
+  //
+  Status = gMmst->MmLocateProtocol (
+                    &gEfiSmmFirmwareVolumeBlockProtocolGuid,
+                    NULL,
+                    (VOID **) &FvbProtocol
+                    );
+  ASSERT_EFI_ERROR (Status);
+
+  Instance = INSTANCE_FROM_FVB_THIS(FvbProtocol);
+  // Patch PCDs with the the correct values
+  PatchPcdSet32 (PcdFlashNvStorageVariableBase, Instance->MemBaseAddress);
+  PatchPcdSet32 (PcdFlashNvStorageFtwWorkingBase, Instance->MemBaseAddress +
+    PcdGet32 (PcdFlashNvStorageVariableSize));
+  PatchPcdSet32 (PcdFlashNvStorageFtwSpareBase, Instance->MemBaseAddress +
+    PcdGet32 (PcdFlashNvStorageVariableSize) +
+    PcdGet32 (PcdFlashNvStorageFtwWorkingSize));
+
+  DEBUG ((DEBUG_INFO, "%a: Fixup PcdFlashNvStorageVariableBase: 0x%lx\n",
+    __FUNCTION__, PcdGet32 (PcdFlashNvStorageVariableBase)));
+  DEBUG ((DEBUG_INFO, "%a: Fixup PcdFlashNvStorageFtwWorkingBase: 0x%lx\n",
+    __FUNCTION__, PcdGet32 (PcdFlashNvStorageFtwWorkingBase)));
+  DEBUG ((DEBUG_INFO, "%a: Fixup PcdFlashNvStorageFtwSpareBase: 0x%lx\n",
+    __FUNCTION__, PcdGet32 (PcdFlashNvStorageFtwSpareBase)));
+
+  return Status;
+}
diff --git a/Drivers/OpTeeRpmb/OpTeeRpmbFvb.c b/Drivers/OpTeeRpmb/OpTeeRpmbFvb.c
new file mode 100644
index 0000000000..27b857da22
--- /dev/null
+++ b/Drivers/OpTeeRpmb/OpTeeRpmbFvb.c
@@ -0,0 +1,775 @@
+/** @file
+
+  FV block I/O protocol driver for RPMB eMMC accessed via OP-TEE
+
+  Copyright (c) 2020, Linaro Ltd. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/ArmSvcLib.h>
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/DebugLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/MmServicesTableLib.h>
+#include <Library/PcdLib.h>
+
+#include <IndustryStandard/ArmFfaSvc.h>
+#include <Protocol/FirmwareVolumeBlock.h>
+#include <Protocol/SmmFirmwareVolumeBlock.h>
+#include <Guid/VariableFormat.h>
+
+#include "OpTeeRpmbFvb.h"
+
+static const UINT16 mem_mgr_id = 3U;
+static const UINT16 storage_id = 4U;
+
+STATIC MEM_INSTANCE mInstance;
+
+/**
+  Sends an SVC call to OP-TEE for reading/writing an RPMB partition
+
+  @param SvcAct     SVC ID for read/write
+  @param Addr       Base address of the buffer. When reading contents will be
+                    copied to that buffer after reading them from the device.
+                    When writing, the buffer holds the contents we want to
+                    write cwtoin the device
+  @param NumBytes   Number of bytes to read/write
+  @param Offset     Offset into the RPMB file
+
+  @retval           OP-TEE return code
+**/
+
+STATIC
+UINTN
+ReadWriteRpmb (
+  UINTN  SvcAct,
+  UINTN  Addr,
+  UINTN  NumBytes,
+  UINTN  Offset
+  )
+{
+  ARM_SVC_ARGS  SvcArgs;
+
+  ZeroMem (&SvcArgs, sizeof (SvcArgs));
+
+  SvcArgs.Arg0 = ARM_SVC_ID_FFA_MSG_SEND_DIRECT_REQ_AARCH64;
+  SvcArgs.Arg1 = storage_id;
+  SvcArgs.Arg2 = 0;
+  SvcArgs.Arg3 = SvcAct;
+  SvcArgs.Arg4 = Addr;
+  SvcArgs.Arg5 = NumBytes;
+  SvcArgs.Arg6 = Offset;
+
+  ArmCallSvc (&SvcArgs);
+  if (SvcArgs.Arg3) {
+    DEBUG ((DEBUG_ERROR, "%a: Svc Call 0x%08x Addr: 0x%08x len: 0x%x Offset: 0x%x failed with 0x%x\n",
+     __func__, SvcAct, Addr, NumBytes, Offset, SvcArgs.Arg3));
+  }
+
+  return SvcArgs.Arg3;
+}
+
+/**
+  The GetAttributes() function retrieves the attributes and
+  current settings of the block.
+
+  @param This       Indicates the EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL instance.
+
+  @param Attributes Pointer to EFI_FVB_ATTRIBUTES_2 in which the
+                    attributes and current settings are
+                    returned. Type EFI_FVB_ATTRIBUTES_2 is defined
+                    in EFI_FIRMWARE_VOLUME_HEADER.
+
+  @retval EFI_SUCCESS The firmware volume attributes were
+                      returned.
+
+**/
+STATIC
+EFI_STATUS
+OpTeeRpmbFvbGetAttributes (
+  IN CONST  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL *This,
+  OUT       EFI_FVB_ATTRIBUTES_2                *Attributes
+  )
+{
+  *Attributes = EFI_FVB2_READ_ENABLED_CAP   | // Reads may be enabled
+                EFI_FVB2_READ_STATUS        | // Reads are currently enabled
+                EFI_FVB2_WRITE_STATUS       | // Writes are currently enabled
+                EFI_FVB2_WRITE_ENABLED_CAP  | // Writes may be enabled
+                EFI_FVB2_STICKY_WRITE       | // A block erase is required to flip bits into EFI_FVB2_ERASE_POLARITY
+                EFI_FVB2_MEMORY_MAPPED      | // It is memory mapped
+                EFI_FVB2_ERASE_POLARITY;      // After erasure all bits take this value (i.e. '1')
+
+  return EFI_SUCCESS;
+}
+
+/**
+  The SetAttributes() function sets configurable firmware volume
+  attributes and returns the new settings of the firmware volume.
+
+  @param This         Indicates the EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL instance.
+
+  @param Attributes   On input, Attributes is a pointer to
+                      EFI_FVB_ATTRIBUTES_2 that contains the
+                      desired firmware volume settings. On
+                      successful return, it contains the new
+                      settings of the firmware volume. Type
+                      EFI_FVB_ATTRIBUTES_2 is defined in
+                      EFI_FIRMWARE_VOLUME_HEADER.
+
+  @retval EFI_SUCCESS           The firmware volume attributes were returned.
+
+  @retval EFI_INVALID_PARAMETER The attributes requested are in
+                                conflict with the capabilities
+                                as declared in the firmware
+                                volume header.
+
+**/
+STATIC
+EFI_STATUS
+OpTeeRpmbFvbSetAttributes (
+  IN CONST  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL *This,
+  IN OUT    EFI_FVB_ATTRIBUTES_2                *Attributes
+  )
+{
+  return EFI_SUCCESS;  // ignore for now
+}
+
+/**
+  The GetPhysicalAddress() function retrieves the base address of
+  a memory-mapped firmware volume. This function should be called
+  only for memory-mapped firmware volumes.
+
+  @param This     Indicates the EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL instance.
+
+  @param Address  Pointer to a caller-allocated
+                  EFI_PHYSICAL_ADDRESS that, on successful
+                  return from GetPhysicalAddress(), contains the
+                  base address of the firmware volume.
+
+  @retval EFI_SUCCESS       The firmware volume base address was returned.
+
+  @retval EFI_UNSUPPORTED   The firmware volume is not memory mapped.
+
+**/
+STATIC
+EFI_STATUS
+OpTeeRpmbFvbGetPhysicalAddress (
+  IN CONST  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL *This,
+  OUT       EFI_PHYSICAL_ADDRESS                *Address
+  )
+{
+  MEM_INSTANCE *Instance;
+
+  Instance = INSTANCE_FROM_FVB_THIS(This);
+  *Address = Instance->MemBaseAddress;
+
+  return EFI_SUCCESS;
+}
+
+/**
+  The GetBlockSize() function retrieves the size of the requested
+  block. It also returns the number of additional blocks with
+  the identical size. The GetBlockSize() function is used to
+  retrieve the block map (see EFI_FIRMWARE_VOLUME_HEADER).
+
+
+  @param This           Indicates the EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL instance.
+
+  @param Lba            Indicates the block for which to return the size.
+
+  @param BlockSize      Pointer to a caller-allocated UINTN in which
+                        the size of the block is returned.
+
+  @param NumberOfBlocks Pointer to a caller-allocated UINTN in
+                        which the number of consecutive blocks,
+                        starting with Lba, is returned. All
+                        blocks in this range have a size of
+                        BlockSize.
+
+
+  @retval EFI_SUCCESS             The firmware volume base address was returned.
+
+  @retval EFI_INVALID_PARAMETER   The requested LBA is out of range.
+
+**/
+STATIC
+EFI_STATUS
+OpTeeRpmbFvbGetBlockSize (
+  IN CONST  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL *This,
+  IN        EFI_LBA                            Lba,
+  OUT       UINTN                              *BlockSize,
+  OUT       UINTN                              *NumberOfBlocks
+  )
+{
+  MEM_INSTANCE *Instance;
+
+  Instance = INSTANCE_FROM_FVB_THIS(This);
+  if (Lba >= Instance->NBlocks) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  *NumberOfBlocks = Instance->NBlocks - (UINTN) Lba;
+  *BlockSize = Instance->BlockSize;
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Reads the specified number of bytes into a buffer from the specified block.
+
+  The Read() function reads the requested number of bytes from the
+  requested block and stores them in the provided buffer.
+  Implementations should be mindful that the firmware volume
+  might be in the ReadDisabled state. If it is in this state,
+  the Read() function must return the status code
+  EFI_ACCESS_DENIED without modifying the contents of the
+  buffer. The Read() function must also prevent spanning block
+  boundaries. If a read is requested that would span a block
+  boundary, the read must read up to the boundary but not
+  beyond. The output parameter NumBytes must be set to correctly
+  indicate the number of bytes actually read. The caller must be
+  aware that a read may be partially completed.
+
+  @param This     Indicates the EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL instance.
+
+  @param Lba      The starting logical block index
+                  from which to read.
+
+  @param Offset   Offset into the block at which to begin reading.
+
+  @param NumBytes Pointer to a UINTN. At entry, *NumBytes
+                  contains the total size of the buffer. At
+                  exit, *NumBytes contains the total number of
+                  bytes read.
+
+  @param Buffer   Pointer to a caller-allocated buffer that will
+                  be used to hold the data that is read.
+
+  @retval EFI_SUCCESS         The firmware volume was read successfully,
+                              and contents are in Buffer.
+
+  @retval EFI_BAD_BUFFER_SIZE Read attempted across an LBA
+                              boundary. On output, NumBytes
+                              contains the total number of bytes
+                              returned in Buffer.
+
+  @retval EFI_ACCESS_DENIED   The firmware volume is in the
+                              ReadDisabled state.
+
+  @retval EFI_DEVICE_ERROR    The block device is not
+                              functioning correctly and could
+                              not be read.
+
+**/
+
+STATIC
+EFI_STATUS
+OpTeeRpmbFvbRead (
+  IN CONST  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL *This,
+  IN        EFI_LBA                             Lba,
+  IN        UINTN                               Offset,
+  IN OUT    UINTN                               *NumBytes,
+  IN OUT    UINT8                               *Buffer
+  )
+{
+  EFI_STATUS   Status = EFI_SUCCESS;
+  MEM_INSTANCE *Instance;
+  VOID         *Base;
+
+  Instance = INSTANCE_FROM_FVB_THIS(This);
+  if (Instance->Initialized == FALSE) {
+    Instance->Initialize (Instance);
+  }
+
+  Base = (VOID *)Instance->MemBaseAddress + Lba * Instance->BlockSize + Offset;
+  // We could read the data from the RPMB instead of memory
+  // The 2 copies should already be identical
+  // Copy from memory image
+  CopyMem (Buffer, Base, *NumBytes);
+
+  return Status;
+}
+
+/**
+  Writes the specified number of bytes from the input buffer to the block.
+
+  The Write() function writes the specified number of bytes from
+  the provided buffer to the specified block and offset. If the
+  firmware volume is sticky write, the caller must ensure that
+  all the bits of the specified range to write are in the
+  EFI_FVB_ERASE_POLARITY state before calling the Write()
+  function, or else the result will be unpredictable. This
+  unpredictability arises because, for a sticky-write firmware
+  volume, a write may negate a bit in the EFI_FVB_ERASE_POLARITY
+  state but cannot flip it back again.  Before calling the
+  Write() function,  it is recommended for the caller to first call
+  the EraseBlocks() function to erase the specified block to
+  write. A block erase cycle will transition bits from the
+  (NOT)EFI_FVB_ERASE_POLARITY state back to the
+  EFI_FVB_ERASE_POLARITY state. Implementations should be
+  mindful that the firmware volume might be in the WriteDisabled
+  state. If it is in this state, the Write() function must
+  return the status code EFI_ACCESS_DENIED without modifying the
+  contents of the firmware volume. The Write() function must
+  also prevent spanning block boundaries. If a write is
+  requested that spans a block boundary, the write must store up
+  to the boundary but not beyond. The output parameter NumBytes
+  must be set to correctly indicate the number of bytes actually
+  written. The caller must be aware that a write may be
+  partially completed. All writes, partial or otherwise, must be
+  fully flushed to the hardware before the Write() service
+  returns.
+
+  @param This     Indicates the EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL instance.
+
+  @param Lba      The starting logical block index to write to.
+
+  @param Offset   Offset into the block at which to begin writing.
+
+  @param NumBytes The pointer to a UINTN. At entry, *NumBytes
+                  contains the total size of the buffer. At
+                  exit, *NumBytes contains the total number of
+                  bytes actually written.
+
+  @param Buffer   The pointer to a caller-allocated buffer that
+                  contains the source for the write.
+
+  @retval EFI_SUCCESS         The firmware volume was written successfully.
+
+  @retval EFI_BAD_BUFFER_SIZE The write was attempted across an
+                              LBA boundary. On output, NumBytes
+                              contains the total number of bytes
+                              actually written.
+
+  @retval EFI_ACCESS_DENIED   The firmware volume is in the
+                              WriteDisabled state.
+
+  @retval EFI_DEVICE_ERROR    The block device is malfunctioning
+                              and could not be written.
+
+
+**/
+STATIC
+EFI_STATUS
+OpTeeRpmbFvbWrite (
+  IN CONST  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL *This,
+  IN        EFI_LBA                             Lba,
+  IN        UINTN                               Offset,
+  IN OUT    UINTN                               *NumBytes,
+  IN        UINT8                               *Buffer
+  )
+{
+  MEM_INSTANCE *Instance;
+  EFI_STATUS   Status = EFI_SUCCESS;
+  VOID         *Base;
+  UINTN        Ret;
+
+  Instance = INSTANCE_FROM_FVB_THIS(This);
+  if (Instance->Initialized == FALSE) {
+    Instance->Initialize (Instance);
+  }
+  Base = (VOID *)Instance->MemBaseAddress + Lba * Instance->BlockSize + Offset;
+  // We can map OP-TEE errors to EFI exitcodes and  return a more
+  // realistic error. Keep it simple for now
+  Ret = ReadWriteRpmb (SP_SVC_RPMB_WRITE, (UINTN) Buffer, *NumBytes,
+    Lba * Instance->BlockSize + Offset);
+  if (Ret) {
+    return EFI_DEVICE_ERROR;
+  }
+
+  // Update the memory copy
+  CopyMem (Base, Buffer, *NumBytes);
+
+  return Status;
+}
+
+/**
+  Erases and initializes a firmware volume block.
+
+  The EraseBlocks() function erases one or more blocks as denoted
+  by the variable argument list. The entire parameter list of
+  blocks must be verified before erasing any blocks. If a block is
+  requested that does not exist within the associated firmware
+  volume (it has a larger index than the last block of the
+  firmware volume), the EraseBlocks() function must return the
+  status code EFI_INVALID_PARAMETER without modifying the contents
+  of the firmware volume. Implementations should be mindful that
+  the firmware volume might be in the WriteDisabled state. If it
+  is in this state, the EraseBlocks() function must return the
+  status code EFI_ACCESS_DENIED without modifying the contents of
+  the firmware volume. All calls to EraseBlocks() must be fully
+  flushed to the hardware before the EraseBlocks() service
+  returns.
+
+  @param This   Indicates the EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL
+                instance.
+
+  @param ...    The variable argument list is a list of tuples.
+                Each tuple describes a range of LBAs to erase
+                and consists of the following:
+                - An EFI_LBA that indicates the starting LBA
+                - A UINTN that indicates the number of blocks to
+                  erase.
+
+                The list is terminated with an
+                EFI_LBA_LIST_TERMINATOR. For example, the
+                following indicates that two ranges of blocks
+                (5-7 and 10-11) are to be erased: EraseBlocks
+                (This, 5, 3, 10, 2, EFI_LBA_LIST_TERMINATOR);
+
+  @retval EFI_SUCCESS The erase request successfully
+                      completed.
+
+  @retval EFI_ACCESS_DENIED   The firmware volume is in the
+                              WriteDisabled state.
+  @retval EFI_DEVICE_ERROR  The block device is not functioning
+                            correctly and could not be written.
+                            The firmware device may have been
+                            partially erased.
+  @retval EFI_INVALID_PARAMETER One or more of the LBAs listed
+                                in the variable argument list do
+                                not exist in the firmware volume.
+
+**/
+STATIC
+EFI_STATUS
+OpTeeRpmbFvbErase (
+  IN CONST  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL *This,
+  ...
+  )
+{
+  MEM_INSTANCE *Instance;
+  UINTN   NumBytes;
+  UINTN   NumLba;
+  EFI_LBA Start;
+  VOID    *Base;
+  VOID    *Buf;
+  VA_LIST Args;
+  UINTN   Ret;
+
+  Instance = INSTANCE_FROM_FVB_THIS(This);
+
+  VA_START (Args, This);
+  for (Start = VA_ARG (Args, EFI_LBA);
+       Start != EFI_LBA_LIST_TERMINATOR;
+       Start = VA_ARG (Args, EFI_LBA)) {
+    NumLba = VA_ARG (Args, UINTN);
+    if (Start + NumLba >= Instance->NBlocks) {
+      return EFI_INVALID_PARAMETER;
+    }
+    NumBytes = NumLba * Instance->BlockSize;
+    Base = (VOID *)Instance->MemBaseAddress + Start * Instance->BlockSize;
+    Buf = AllocatePool(NumLba * Instance->BlockSize);
+    SetMem64 (Buf, NumLba * Instance->BlockSize, ~0UL);
+    if (!Buf) {
+      return EFI_DEVICE_ERROR;
+    }
+    // Write the device
+    Ret = ReadWriteRpmb (SP_SVC_RPMB_WRITE, (UINTN) Buf, NumBytes,
+     Start * Instance->BlockSize);
+    if (Ret) {
+      return EFI_DEVICE_ERROR;
+    }
+    // Update the in memory copy
+    SetMem64 (Base, NumLba * Instance->BlockSize, ~0UL);
+    FreePool (Buf);
+  }
+
+  VA_END (Args);
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Since we use a memory backed storage we need to restore the RPMB contents
+  into memory before we register the Fvb protocol.
+
+  @param Instace Address to copy flash contents to
+
+  @retval     0 on success, OP-TEE error on failure
+**/
+STATIC
+VOID
+ReadEntireFlash (
+  MEM_INSTANCE *Instance
+ )
+{
+  UINTN ReadAddr;
+
+  UINTN StorageFtwWorkingSize = PcdGet32(PcdFlashNvStorageFtwWorkingSize);
+  UINTN StorageVariableSize   = PcdGet32(PcdFlashNvStorageVariableSize);
+  UINTN StorageFtwSpareSize   = PcdGet32(PcdFlashNvStorageFtwSpareSize);
+
+  ReadAddr = Instance->MemBaseAddress;
+  // There's no need to check if the read failed here. The upper EDK2 layers
+  // will initialize the flash correctly if the in-memory copy is wrong
+  ReadWriteRpmb(SP_SVC_RPMB_READ, ReadAddr, StorageVariableSize +
+    StorageFtwWorkingSize + StorageFtwSpareSize , 0);
+}
+
+
+STATIC
+EFI_STATUS
+EFIAPI
+ValidateFvHeader (
+  IN EFI_FIRMWARE_VOLUME_HEADER            *FwVolHeader
+  )
+{
+  UINT16                      Checksum;
+  VARIABLE_STORE_HEADER       *VariableStoreHeader;
+  UINTN                       VariableStoreLength;
+  UINTN                       FvLength;
+
+  FvLength = PcdGet32(PcdFlashNvStorageVariableSize) +
+             PcdGet32(PcdFlashNvStorageFtwWorkingSize) +
+             PcdGet32(PcdFlashNvStorageFtwSpareSize);
+
+  // Verify the header revision, header signature, length
+  // Length of FvBlock cannot be 2**64-1
+  // HeaderLength cannot be an odd number
+  //
+  if (   (FwVolHeader->Revision  != EFI_FVH_REVISION)
+      || (FwVolHeader->Signature != EFI_FVH_SIGNATURE)
+      || (FwVolHeader->FvLength  != FvLength)
+      )
+  {
+    DEBUG ((DEBUG_INFO, "%a: No Firmware Volume header present\n",
+      __FUNCTION__));
+    return EFI_NOT_FOUND;
+  }
+
+  // Check the Firmware Volume Guid
+  if (!CompareGuid (&FwVolHeader->FileSystemGuid, &gEfiSystemNvDataFvGuid)) {
+    DEBUG ((DEBUG_INFO, "%a: Firmware Volume Guid non-compatible\n",
+      __FUNCTION__));
+    return EFI_NOT_FOUND;
+  }
+
+  // Verify the header checksum
+  Checksum = CalculateSum16((UINT16*)FwVolHeader, FwVolHeader->HeaderLength);
+  if (Checksum != 0) {
+    DEBUG ((DEBUG_INFO, "%a: FV checksum is invalid (Checksum:0x%X)\n",
+      __FUNCTION__, Checksum));
+    return EFI_NOT_FOUND;
+  }
+
+  VariableStoreHeader = (VOID *)((UINTN)FwVolHeader +
+                                 FwVolHeader->HeaderLength);
+
+  // Check the Variable Store Guid
+  if (!CompareGuid (&VariableStoreHeader->Signature, &gEfiVariableGuid) &&
+      !CompareGuid (&VariableStoreHeader->Signature,
+        &gEfiAuthenticatedVariableGuid)) {
+    DEBUG ((DEBUG_INFO, "%a: Variable Store Guid non-compatible\n",
+      __FUNCTION__));
+    return EFI_NOT_FOUND;
+  }
+
+  VariableStoreLength = PcdGet32 (PcdFlashNvStorageVariableSize) -
+                        FwVolHeader->HeaderLength;
+  if (VariableStoreHeader->Size != VariableStoreLength) {
+    DEBUG ((DEBUG_INFO, "%a: Variable Store Length does not match\n",
+      __FUNCTION__));
+    return EFI_NOT_FOUND;
+  }
+
+  return EFI_SUCCESS;
+
+}
+
+STATIC
+EFI_STATUS
+InitializeFvAndVariableStoreHeaders (
+  MEM_INSTANCE *Instance
+  )
+{
+  EFI_FIRMWARE_VOLUME_HEADER *FirmwareVolumeHeader;
+  VARIABLE_STORE_HEADER      *VariableStoreHeader;
+  EFI_STATUS                 Status = EFI_SUCCESS;
+  UINTN                      HeadersLength;
+  VOID*                      Headers;
+  UINTN                      Ret;
+
+  HeadersLength = sizeof(EFI_FIRMWARE_VOLUME_HEADER) +
+                  sizeof(EFI_FV_BLOCK_MAP_ENTRY) +
+                  sizeof(VARIABLE_STORE_HEADER);
+  Headers = AllocateZeroPool(HeadersLength);
+
+  //
+  // EFI_FIRMWARE_VOLUME_HEADER
+  //
+  FirmwareVolumeHeader = (EFI_FIRMWARE_VOLUME_HEADER*)Headers;
+  CopyGuid (&FirmwareVolumeHeader->FileSystemGuid, &gEfiSystemNvDataFvGuid);
+  FirmwareVolumeHeader->FvLength =
+      PcdGet32(PcdFlashNvStorageVariableSize) +
+      PcdGet32(PcdFlashNvStorageFtwWorkingSize) +
+      PcdGet32(PcdFlashNvStorageFtwSpareSize);
+  FirmwareVolumeHeader->Signature = EFI_FVH_SIGNATURE;
+  FirmwareVolumeHeader->Attributes = EFI_FVB2_READ_ENABLED_CAP |
+                                     EFI_FVB2_READ_STATUS |
+                                     EFI_FVB2_STICKY_WRITE |
+                                     EFI_FVB2_MEMORY_MAPPED |
+                                     EFI_FVB2_ERASE_POLARITY |
+                                     EFI_FVB2_WRITE_STATUS |
+                                     EFI_FVB2_WRITE_ENABLED_CAP;
+
+  FirmwareVolumeHeader->HeaderLength = sizeof(EFI_FIRMWARE_VOLUME_HEADER) +
+                                       sizeof(EFI_FV_BLOCK_MAP_ENTRY);
+  FirmwareVolumeHeader->Revision = EFI_FVH_REVISION;
+  FirmwareVolumeHeader->BlockMap[0].NumBlocks = Instance->NBlocks;
+  FirmwareVolumeHeader->BlockMap[0].Length    = Instance->BlockSize;
+  FirmwareVolumeHeader->BlockMap[1].NumBlocks = 0;
+  FirmwareVolumeHeader->BlockMap[1].Length    = 0;
+  FirmwareVolumeHeader->Checksum = CalculateCheckSum16 (
+                                     (UINT16*)FirmwareVolumeHeader,
+                                     FirmwareVolumeHeader->HeaderLength);
+
+  //
+  // VARIABLE_STORE_HEADER
+  //
+  VariableStoreHeader = (VOID *)((UINTN)Headers +
+                                 FirmwareVolumeHeader->HeaderLength);
+  CopyGuid (&VariableStoreHeader->Signature, &gEfiAuthenticatedVariableGuid);
+  VariableStoreHeader->Size = PcdGet32(PcdFlashNvStorageVariableSize) -
+                              FirmwareVolumeHeader->HeaderLength;
+  VariableStoreHeader->Format = VARIABLE_STORE_FORMATTED;
+  VariableStoreHeader->State = VARIABLE_STORE_HEALTHY;
+
+  Ret = ReadWriteRpmb(SP_SVC_RPMB_WRITE, (UINTN) Headers, HeadersLength, 0);
+  if (Ret) {
+    Status = EFI_DEVICE_ERROR;
+    goto Exit;
+  }
+  // Install the combined header in memory
+  CopyMem ((VOID*) Instance->MemBaseAddress, Headers, HeadersLength);
+
+Exit:
+  FreePool (Headers);
+  return Status;
+}
+
+STATIC
+EFI_STATUS
+EFIAPI
+FvbInitialize (
+  MEM_INSTANCE *Instance
+  )
+{
+  EFI_FIRMWARE_VOLUME_HEADER *FwVolHeader;
+  EFI_STATUS                  Status;
+  UINTN                       Ret;
+
+  if (Instance->Initialized == TRUE) {
+    return EFI_SUCCESS;
+  }
+
+  // FirmwareVolumeHeader->FvLength is declared to have the Variable area
+  // AND the FTW working area AND the FTW Spare contiguous.
+  ASSERT (PcdGet32 (PcdFlashNvStorageVariableBase) +
+          PcdGet32 (PcdFlashNvStorageVariableSize) ==
+          PcdGet32 (PcdFlashNvStorageFtwWorkingBase));
+  ASSERT (PcdGet32 (PcdFlashNvStorageFtwWorkingBase) +
+          PcdGet32 (PcdFlashNvStorageFtwWorkingSize) ==
+          PcdGet32 (PcdFlashNvStorageFtwSpareBase));
+
+  // Check if the size of the area is at least one block size
+  ASSERT ((PcdGet32 (PcdFlashNvStorageVariableSize) > 0) &&
+          (PcdGet32 (PcdFlashNvStorageVariableSize) / Instance->BlockSize > 0));
+  ASSERT ((PcdGet32 (PcdFlashNvStorageFtwWorkingSize) > 0) &&
+          (PcdGet32 (PcdFlashNvStorageFtwWorkingSize) / Instance->BlockSize > 0));
+  ASSERT ((PcdGet32 (PcdFlashNvStorageFtwSpareSize) > 0) &&
+          (PcdGet32 (PcdFlashNvStorageFtwSpareSize) / Instance->BlockSize > 0));
+
+  // Ensure the Variable areas are aligned on block size boundaries
+  ASSERT ((PcdGet32 (PcdFlashNvStorageVariableBase) % Instance->BlockSize) == 0);
+  ASSERT ((PcdGet32 (PcdFlashNvStorageFtwWorkingBase) % Instance->BlockSize) == 0);
+  ASSERT ((PcdGet32 (PcdFlashNvStorageFtwSpareBase) % Instance->BlockSize) == 0);
+
+  // Read the file from disk and copy it to memory
+  ReadEntireFlash (Instance);
+
+  FwVolHeader = (EFI_FIRMWARE_VOLUME_HEADER *) Instance->MemBaseAddress;
+  Status = ValidateFvHeader(FwVolHeader);
+  if (EFI_ERROR (Status)) {
+    // There is no valid header, so time to install one.
+    DEBUG ((DEBUG_INFO, "%a: The FVB Header is not valid.\n", __FUNCTION__));
+
+    // Reset memory
+    SetMem64 ((VOID *)Instance->MemBaseAddress, Instance->NBlocks * Instance->BlockSize, ~0UL);
+    DEBUG ((DEBUG_INFO, "%a: Erasing Flash.\n", __FUNCTION__));
+    Ret = ReadWriteRpmb(SP_SVC_RPMB_WRITE, Instance->MemBaseAddress,
+      PcdGet32(PcdFlashNvStorageVariableSize) +
+      PcdGet32(PcdFlashNvStorageFtwWorkingSize) +
+      PcdGet32(PcdFlashNvStorageFtwSpareSize), 0);
+    if (Ret) {
+      return EFI_DEVICE_ERROR;
+    }
+    // Install all appropriate headers
+    DEBUG ((DEBUG_INFO, "%a: Installing a correct one for this volume.\n",
+      __FUNCTION__));
+    Status = InitializeFvAndVariableStoreHeaders (Instance);
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+  } else {
+    DEBUG ((DEBUG_INFO, "%a: Found valid FVB Header.\n", __FUNCTION__));
+  }
+  Instance->Initialized = TRUE;
+
+  return Status;
+}
+
+EFI_STATUS
+EFIAPI
+OpTeeRpmbFvbInit (
+  IN EFI_HANDLE           ImageHandle,
+  IN EFI_MM_SYSTEM_TABLE  *SystemTable
+  )
+{
+  EFI_STATUS   Status;
+  VOID         *Addr;
+
+  Addr = AllocatePages(NBLOCKS);
+  ASSERT (Addr != NULL);
+
+  SetMem (&mInstance, sizeof (mInstance), 0);
+
+  mInstance.FvbProtocol.GetPhysicalAddress = OpTeeRpmbFvbGetPhysicalAddress;
+  mInstance.FvbProtocol.GetAttributes      = OpTeeRpmbFvbGetAttributes;
+  mInstance.FvbProtocol.SetAttributes      = OpTeeRpmbFvbSetAttributes;
+  mInstance.FvbProtocol.GetBlockSize       = OpTeeRpmbFvbGetBlockSize;
+  mInstance.FvbProtocol.EraseBlocks        = OpTeeRpmbFvbErase;
+  mInstance.FvbProtocol.Write              = OpTeeRpmbFvbWrite;
+  mInstance.FvbProtocol.Read               = OpTeeRpmbFvbRead;
+
+  mInstance.MemBaseAddress = (EFI_PHYSICAL_ADDRESS) Addr;
+  mInstance.Signature      = FLASH_SIGNATURE;
+  mInstance.Initialize     = FvbInitialize;
+  mInstance.BlockSize      = BLOCK_SIZE;
+  mInstance.NBlocks        = NBLOCKS;
+
+  // Update the defined PCDs related to Variable Storage
+  PatchPcdSet32 (PcdFlashNvStorageVariableBase, mInstance.MemBaseAddress);
+  PatchPcdSet32 (PcdFlashNvStorageFtwWorkingBase, mInstance.MemBaseAddress +
+    PcdGet32 (PcdFlashNvStorageVariableSize));
+  PatchPcdSet32 (PcdFlashNvStorageFtwSpareBase, mInstance.MemBaseAddress +
+    PcdGet32 (PcdFlashNvStorageVariableSize) +
+    PcdGet32 (PcdFlashNvStorageFtwWorkingSize));
+
+  Status = gMmst->MmInstallProtocolInterface (
+                    &mInstance.Handle,
+                    &gEfiSmmFirmwareVolumeBlockProtocolGuid,
+                    EFI_NATIVE_INTERFACE,
+                    &mInstance.FvbProtocol
+                    );
+  ASSERT_EFI_ERROR (Status);
+
+  DEBUG ((DEBUG_INFO, "%a: Register OP-TEE RPMB Fvb\n", __FUNCTION__));
+  DEBUG ((DEBUG_INFO, "%a: Using NV store FV in-memory copy at 0x%lx\n",
+    __FUNCTION__, PatchPcdGet32 (PcdFlashNvStorageVariableBase)));
+
+  return Status;
+}
-- 
2.17.1