MdeModulePkg/Library/ArmFfaLib/ArmFfaSecRxTxMap.c

/** @file
  Arm Ffa library common code.

  Copyright (c) 2025, Arm Limited. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

   @par Glossary:
     - FF-A - Firmware Framework for Arm A-profile

   @par Reference(s):
     - Arm Firmware Framework for Arm A-Profile [https://developer.arm.com/documentation/den0077/latest]

**/
#include <Uefi.h>
#include <Pi/PiMultiPhase.h>

#include <Library/ArmLib.h>
#include <Library/ArmFfaLib.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/HobLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/PcdLib.h>
#include <Library/UefiBootServicesTableLib.h>

#include <IndustryStandard/ArmFfaSvc.h>

#include <Guid/ArmFfaRxTxBufferInfo.h>

#include "ArmFfaCommon.h"
#include "ArmFfaRxTxMap.h"

STATIC VOID  *mTxBuffer;
STATIC VOID  *mRxBuffer;

/**
  Get mapped Rx/Tx buffers.

  @param [out]   TxBuffer         Address of TxBuffer
  @param [out]   TxBufferSize     Size of TxBuffer
  @param [out]   RxBuffer         Address of RxBuffer
  @param [out]   RxBufferSize     Size of RxBuffer

  @retval EFI_SUCCESS
  @retval Others             Error.

**/
EFI_STATUS
EFIAPI
ArmFfaLibGetRxTxBuffers (
  OUT VOID    **TxBuffer OPTIONAL,
  OUT UINT64  *TxBufferSize OPTIONAL,
  OUT VOID    **RxBuffer OPTIONAL,
  OUT UINT64  *RxBufferSize OPTIONAL
  )
{
  if ((mTxBuffer == NULL) || (mRxBuffer == NULL)) {
    return EFI_NOT_READY;
  }

  if (TxBuffer != NULL) {
    *TxBuffer = mTxBuffer;
  }

  if (TxBufferSize != NULL) {
    *TxBufferSize = PcdGet64 (PcdFfaTxRxPageCount) * EFI_PAGE_SIZE;
  }

  if (RxBuffer != NULL) {
    *RxBuffer = mRxBuffer;
  }

  if (RxBufferSize != NULL) {
    *RxBufferSize = PcdGet64 (PcdFfaTxRxPageCount) * EFI_PAGE_SIZE;
  }

  return EFI_SUCCESS;
}

/**
  Mapping Rx/Tx buffers.
  This function is only called in ArmFfaLibConstructor because
  Rx/Tx buffer is registered only once per partition.

  @retval EFI_SUCCESS
  @retval EFI_ALREADY_STARTED     Rx/Tx buffer already mapped.
  @retval EFI_OUT_OF_RESOURCE     Out of memory
  @retval EFI_INVALID_PARAMETER   Invalid alignment of Rx/Tx buffer
  @retval Others                  Error

**/
EFI_STATUS
EFIAPI
ArmFfaLibRxTxMap (
  IN VOID
  )
{
  EFI_STATUS    Status;
  ARM_FFA_ARGS  FfaArgs;
  UINTN         Property1;
  UINTN         Property2;
  UINTN         MinSizeAndAlign;
  UINTN         MaxSize;
  VOID          *Buffers;
  VOID          *TxBuffer;
  VOID          *RxBuffer;

  /*
   * If someone already mapped Rx/Tx Buffers, return EFI_ALREADY_STARTED.
   * return EFI_ALREADY_STARTED.
   */
  if ((mTxBuffer != NULL) && (mRxBuffer != NULL)) {
    return EFI_ALREADY_STARTED;
  }

  Status = ArmFfaLibGetFeatures (
             ARM_FID_FFA_RXTX_MAP,
             FFA_RXTX_MAP_INPUT_PROPERTY_DEFAULT,
             &Property1,
             &Property2
             );
  if (EFI_ERROR (Status)) {
    DEBUG ((
      DEBUG_ERROR,
      "%a: Failed to get RX/TX buffer property... Status: %r\n",
      __func__,
      Status
      ));
    return Status;
  }

  ZeroMem (&FfaArgs, sizeof (ARM_FFA_ARGS));

  MinSizeAndAlign =
    ((Property1 >>
      ARM_FFA_BUFFER_MINSIZE_AND_ALIGN_SHIFT) &
     ARM_FFA_BUFFER_MINSIZE_AND_ALIGN_MASK);

  switch (MinSizeAndAlign) {
    case ARM_FFA_BUFFER_MINSIZE_AND_ALIGN_4K:
      MinSizeAndAlign = SIZE_4KB;
      break;
    case ARM_FFA_BUFFER_MINSIZE_AND_ALIGN_16K:
      MinSizeAndAlign = SIZE_16KB;
      break;
    case ARM_FFA_BUFFER_MINSIZE_AND_ALIGN_64K:
      MinSizeAndAlign = SIZE_64KB;
      break;
    default:
      DEBUG ((DEBUG_ERROR, "%a: Invalid MinSizeAndAlign: 0x%x\n", __func__, MinSizeAndAlign));
      return EFI_UNSUPPORTED;
  }

  MaxSize =
    (((Property1 >>
       ARM_FFA_BUFFER_MAXSIZE_PAGE_COUNT_SHIFT) &
      ARM_FFA_BUFFER_MAXSIZE_PAGE_COUNT_MASK));

  MaxSize = ((MaxSize == 0) ? MAX_UINTN : (MaxSize * MinSizeAndAlign));

  if ((MinSizeAndAlign > (PcdGet64 (PcdFfaTxRxPageCount) * EFI_PAGE_SIZE)) ||
      (MaxSize < (PcdGet64 (PcdFfaTxRxPageCount) * EFI_PAGE_SIZE)))
  {
    DEBUG ((
      DEBUG_ERROR,
      "%a: Buffer is too small! MinSize: 0x%x, MaxSize: 0x%x, PageCount: %d\n",
      __func__,
      MinSizeAndAlign,
      MaxSize,
      PcdGet64 (PcdFfaTxRxPageCount)
      ));
    return EFI_INVALID_PARAMETER;
  }

  Buffers = AllocateAlignedPages ((PcdGet64 (PcdFfaTxRxPageCount) * 2), MinSizeAndAlign);
  if (Buffers == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  TxBuffer = Buffers;
  RxBuffer = Buffers + (PcdGet64 (PcdFfaTxRxPageCount) * EFI_PAGE_SIZE);

  FfaArgs.Arg0 = ARM_FID_FFA_RXTX_MAP;
  FfaArgs.Arg1 = (UINTN)TxBuffer;
  FfaArgs.Arg2 = (UINTN)RxBuffer;

  /*
   * PcdFfaTxRxPageCount sets with count of EFI_PAGE_SIZE granularity
   * But, PageCounts for Tx/Rx buffer should set with
   * count of Tx/Rx Buffer's MinSizeAndAlign. granularity.
   */
  FfaArgs.Arg3 = PcdGet64 (PcdFfaTxRxPageCount) / EFI_SIZE_TO_PAGES (MinSizeAndAlign);

  ArmCallFfa (&FfaArgs);

  Status = FfaArgsToEfiStatus (&FfaArgs);
  if (EFI_ERROR (Status)) {
    DEBUG ((
      DEBUG_ERROR,
      "%a: Failed to map Rx/Tx buffer. Status: %r\n",
      __func__,
      Status
      ));
    goto ErrorHandler;
  }

  mTxBuffer = TxBuffer;
  mRxBuffer = RxBuffer;

  return EFI_SUCCESS;

ErrorHandler:
  FreePages (Buffers, (PcdGet64 (PcdFfaTxRxPageCount) * 2));

  return Status;
}

/**
  Unmap Rx/Tx buffer.
  This function is only called in Exit boot service because
  Rx/Tx buffer is registered only once per partition.

  @retval EFI_SUCCESS
  @retval EFI_INVALID_PARAMETERS               Already unregistered
  @retval EFI_UNSUPPORTED                      Not supported

**/
EFI_STATUS
EFIAPI
ArmFfaLibRxTxUnmap (
  IN VOID
  )
{
  EFI_STATUS    Status;
  ARM_FFA_ARGS  FfaArgs;
  VOID          *Buffers;

  ZeroMem (&FfaArgs, sizeof (ARM_FFA_ARGS));

  FfaArgs.Arg0 = ARM_FID_FFA_RXTX_UNMAP;
  FfaArgs.Arg1 = (gPartId << ARM_FFA_SOURCE_EP_SHIFT);

  ArmCallFfa (&FfaArgs);

  Status = FfaArgsToEfiStatus (&FfaArgs);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  /*
   * Rx/Tx Buffer are allocated with continuous pages.
   * and start address of these pages is set on PcdFfaTxBuffer.
   * See ArmFfaLibRxTxMap().
   */
  Buffers = mTxBuffer;
  if (Buffers != NULL) {
    FreePages (Buffers, (PcdGet64 (PcdFfaTxRxPageCount) * 2));
  }

  mTxBuffer = NULL;
  mRxBuffer = NULL;

  return EFI_SUCCESS;
}

/**
  Update Rx/TX buffer information.

  @param  BufferInfo            Rx/Tx buffer information.

**/
VOID
EFIAPI
UpdateRxTxBufferInfo (
  OUT ARM_FFA_RX_TX_BUFFER_INFO  *BufferInfo
  )
{
  BufferInfo->TxBufferAddr = (UINTN)mTxBuffer;
  BufferInfo->TxBufferSize = PcdGet64 (PcdFfaTxRxPageCount) * EFI_PAGE_SIZE;
  BufferInfo->RxBufferAddr = (UINTN)mRxBuffer;
  BufferInfo->RxBufferSize = PcdGet64 (PcdFfaTxRxPageCount) * EFI_PAGE_SIZE;
}

/**
  Find Rx/TX buffer memory allocation hob.

  @param  UseGuid             Find MemoryAllocationHob using Guid.

  @retval MemoryAllocationHob
  @retval NULL                No memory allocation hob related to Rx/Tx buffer

**/
EFI_HOB_MEMORY_ALLOCATION *
EFIAPI
FindRxTxBufferAllocationHob (
  IN BOOLEAN  UseGuid
  )
{
  EFI_PHYSICAL_ADDRESS  BufferBase;
  UINT64                BufferSize;

  BufferBase = (EFI_PHYSICAL_ADDRESS)((UINTN)mTxBuffer);
  BufferSize = PcdGet64 (PcdFfaTxRxPageCount) * EFI_PAGE_SIZE * 2;

  return GetRxTxBufferAllocationHob (BufferBase, BufferSize, UseGuid);
}

/**
  Remap Rx/TX buffer with converted Rx/Tx Buffer address after
  using permanent memory.

  @param[out] BufferInfo    BufferInfo

  @retval EFI_SUCCESS       Success
  @retval EFI_NOT_FOUND     No memory allocation hob related to Rx/Tx buffer

**/
EFI_STATUS
EFIAPI
RemapFfaRxTxBuffer (
  OUT ARM_FFA_RX_TX_BUFFER_INFO  *BufferInfo
  )
{
  /*
   * SEC binary shouldn't remap the Rx/Tx Buffer.
   */
  return EFI_UNSUPPORTED;
}