Separate QemuFwCfgLibMmio.c into two files named QemuFwCfgLibMmio.c and
QemuFwCfgLibMmioDxe.c, added a new header named
QemuFwCfgLibMmioInternal.h for MMIO version.

Build-tested only (with "ArmVirtQemu.dsc and RiscVVirtQemu.dsc").

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4755

Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Gerd Hoffmann <kra...@redhat.com>
Cc: Leif Lindholm <quic_llind...@quicinc.com>
Cc: Sami Mujawar <sami.muja...@arm.com>
Cc: Sunil V L <suni...@ventanamicro.com>
Cc: Andrei Warkentin <andrei.warken...@intel.com>
Signed-off-by: Chao Li <lic...@loongson.cn>
---
 .../Library/QemuFwCfgLib/QemuFwCfgLibMmio.c   | 194 +-----------------
 .../Library/QemuFwCfgLib/QemuFwCfgLibMmio.inf |   4 +-
 .../QemuFwCfgLib/QemuFwCfgLibMmioInternal.h   | 179 ++++++++++++++++
 .../Library/QemuFwCfgLib/QemuFwCfgMmioDxe.c   | 153 ++++++++++++++
 4 files changed, 340 insertions(+), 190 deletions(-)
 create mode 100644 OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmioInternal.h
 create mode 100644 OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioDxe.c

diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmio.c 
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmio.c
index 115a210759..dc949c8e26 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmio.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmio.c
@@ -1,10 +1,9 @@
 /** @file
 
-  Stateful and implicitly initialized fw_cfg library implementation.
-
   Copyright (C) 2013 - 2014, Red Hat, Inc.
   Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>
   (C) Copyright 2021 Hewlett Packard Enterprise Development LP<BR>
+  Copyright (c) 2024 Loongson Technology Corporation Limited. All rights 
reserved.<BR>
 
   SPDX-License-Identifier: BSD-2-Clause-Patent
 **/
@@ -20,63 +19,7 @@
 
 #include <Protocol/FdtClient.h>
 
-STATIC UINTN  mFwCfgSelectorAddress;
-STATIC UINTN  mFwCfgDataAddress;
-STATIC UINTN  mFwCfgDmaAddress;
-
-/**
-  Reads firmware configuration bytes into a buffer
-
-  @param[in] Size    Size in bytes to read
-  @param[in] Buffer  Buffer to store data into  (OPTIONAL if Size is 0)
-
-**/
-typedef
-VOID(EFIAPI READ_BYTES_FUNCTION)(
-  IN UINTN Size,
-  IN VOID  *Buffer OPTIONAL
-  );
-
-/**
-  Writes bytes from a buffer to firmware configuration
-
-  @param[in] Size    Size in bytes to write
-  @param[in] Buffer  Buffer to transfer data from (OPTIONAL if Size is 0)
-
-**/
-typedef
-VOID(EFIAPI WRITE_BYTES_FUNCTION)(
-  IN UINTN Size,
-  IN VOID  *Buffer OPTIONAL
-  );
-
-/**
-  Skips bytes in firmware configuration
-
-  @param[in] Size  Size in bytes to skip
-
-**/
-typedef
-VOID(EFIAPI SKIP_BYTES_FUNCTION)(
-  IN UINTN Size
-  );
-
-//
-// Forward declaration of the two implementations we have.
-//
-STATIC READ_BYTES_FUNCTION   MmioReadBytes;
-STATIC WRITE_BYTES_FUNCTION  MmioWriteBytes;
-STATIC SKIP_BYTES_FUNCTION   MmioSkipBytes;
-STATIC READ_BYTES_FUNCTION   DmaReadBytes;
-STATIC WRITE_BYTES_FUNCTION  DmaWriteBytes;
-STATIC SKIP_BYTES_FUNCTION   DmaSkipBytes;
-
-//
-// These correspond to the implementation we detect at runtime.
-//
-STATIC READ_BYTES_FUNCTION   *InternalQemuFwCfgReadBytes  = MmioReadBytes;
-STATIC WRITE_BYTES_FUNCTION  *InternalQemuFwCfgWriteBytes = MmioWriteBytes;
-STATIC SKIP_BYTES_FUNCTION   *InternalQemuFwCfgSkipBytes  = MmioSkipBytes;
+#include "QemuFwCfgLibMmioInternal.h"
 
 /**
   Returns a boolean indicating if the firmware configuration interface
@@ -97,126 +40,6 @@ QemuFwCfgIsAvailable (
   return (BOOLEAN)(mFwCfgSelectorAddress != 0 && mFwCfgDataAddress != 0);
 }
 
-RETURN_STATUS
-EFIAPI
-QemuFwCfgInitialize (
-  VOID
-  )
-{
-  EFI_STATUS           Status;
-  FDT_CLIENT_PROTOCOL  *FdtClient;
-  CONST UINT64         *Reg;
-  UINT32               RegSize;
-  UINTN                AddressCells, SizeCells;
-  UINT64               FwCfgSelectorAddress;
-  UINT64               FwCfgSelectorSize;
-  UINT64               FwCfgDataAddress;
-  UINT64               FwCfgDataSize;
-  UINT64               FwCfgDmaAddress;
-  UINT64               FwCfgDmaSize;
-
-  Status = gBS->LocateProtocol (
-                  &gFdtClientProtocolGuid,
-                  NULL,
-                  (VOID **)&FdtClient
-                  );
-  ASSERT_EFI_ERROR (Status);
-
-  Status = FdtClient->FindCompatibleNodeReg (
-                        FdtClient,
-                        "qemu,fw-cfg-mmio",
-                        (CONST VOID **)&Reg,
-                        &AddressCells,
-                        &SizeCells,
-                        &RegSize
-                        );
-  if (EFI_ERROR (Status)) {
-    DEBUG ((
-      DEBUG_WARN,
-      "%a: No 'qemu,fw-cfg-mmio' compatible DT node found (Status == %r)\n",
-      __func__,
-      Status
-      ));
-    return EFI_SUCCESS;
-  }
-
-  ASSERT (AddressCells == 2);
-  ASSERT (SizeCells == 2);
-  ASSERT (RegSize == 2 * sizeof (UINT64));
-
-  FwCfgDataAddress     = SwapBytes64 (Reg[0]);
-  FwCfgDataSize        = 8;
-  FwCfgSelectorAddress = FwCfgDataAddress + FwCfgDataSize;
-  FwCfgSelectorSize    = 2;
-
-  //
-  // The following ASSERT()s express
-  //
-  //   Address + Size - 1 <= MAX_UINTN
-  //
-  // for both registers, that is, that the last byte in each MMIO range is
-  // expressible as a MAX_UINTN. The form below is mathematically
-  // equivalent, and it also prevents any unsigned overflow before the
-  // comparison.
-  //
-  ASSERT (FwCfgSelectorAddress <= MAX_UINTN - FwCfgSelectorSize + 1);
-  ASSERT (FwCfgDataAddress     <= MAX_UINTN - FwCfgDataSize     + 1);
-
-  mFwCfgSelectorAddress = FwCfgSelectorAddress;
-  mFwCfgDataAddress     = FwCfgDataAddress;
-
-  DEBUG ((
-    DEBUG_INFO,
-    "Found FwCfg @ 0x%Lx/0x%Lx\n",
-    FwCfgSelectorAddress,
-    FwCfgDataAddress
-    ));
-
-  if (SwapBytes64 (Reg[1]) >= 0x18) {
-    FwCfgDmaAddress = FwCfgDataAddress + 0x10;
-    FwCfgDmaSize    = 0x08;
-
-    //
-    // See explanation above.
-    //
-    ASSERT (FwCfgDmaAddress <= MAX_UINTN - FwCfgDmaSize + 1);
-
-    DEBUG ((DEBUG_INFO, "Found FwCfg DMA @ 0x%Lx\n", FwCfgDmaAddress));
-  } else {
-    FwCfgDmaAddress = 0;
-  }
-
-  if (QemuFwCfgIsAvailable ()) {
-    UINT32  Signature;
-
-    QemuFwCfgSelectItem (QemuFwCfgItemSignature);
-    Signature = QemuFwCfgRead32 ();
-    if (Signature == SIGNATURE_32 ('Q', 'E', 'M', 'U')) {
-      //
-      // For DMA support, we require the DTB to advertise the register, and the
-      // feature bitmap (which we read without DMA) to confirm the feature.
-      //
-      if (FwCfgDmaAddress != 0) {
-        UINT32  Features;
-
-        QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);
-        Features = QemuFwCfgRead32 ();
-        if ((Features & FW_CFG_F_DMA) != 0) {
-          mFwCfgDmaAddress            = FwCfgDmaAddress;
-          InternalQemuFwCfgReadBytes  = DmaReadBytes;
-          InternalQemuFwCfgWriteBytes = DmaWriteBytes;
-          InternalQemuFwCfgSkipBytes  = DmaSkipBytes;
-        }
-      }
-    } else {
-      mFwCfgSelectorAddress = 0;
-      mFwCfgDataAddress     = 0;
-    }
-  }
-
-  return RETURN_SUCCESS;
-}
-
 /**
   Selects a firmware configuration item for reading.
 
@@ -240,7 +63,6 @@ QemuFwCfgSelectItem (
 /**
   Slow READ_BYTES_FUNCTION.
 **/
-STATIC
 VOID
 EFIAPI
 MmioReadBytes (
@@ -252,7 +74,7 @@ MmioReadBytes (
   UINT8  *Ptr;
   UINT8  *End;
 
- #if defined (MDE_CPU_AARCH64) || defined (MDE_CPU_RISCV64)
+ #if defined (MDE_CPU_AARCH64) || defined (MDE_CPU_RISCV64) || defined 
(MDE_CPU_LOONGARCH64)
   Left = Size & 7;
  #else
   Left = Size & 3;
@@ -262,7 +84,7 @@ MmioReadBytes (
   Ptr   = Buffer;
   End   = Ptr + Size;
 
- #if defined (MDE_CPU_AARCH64) || defined (MDE_CPU_RISCV64)
+ #if defined (MDE_CPU_AARCH64) || defined (MDE_CPU_RISCV64) || defined 
(MDE_CPU_LOONGARCH64)
   while (Ptr < End) {
     *(UINT64 *)Ptr = MmioRead64 (mFwCfgDataAddress);
     Ptr           += 8;
@@ -306,7 +128,6 @@ MmioReadBytes (
                           FW_CFG_DMA_CTL_READ  - read from fw_cfg into Buffer.
                           FW_CFG_DMA_CTL_SKIP  - skip bytes in fw_cfg.
 **/
-STATIC
 VOID
 DmaTransferBytes (
   IN     UINTN   Size,
@@ -340,7 +161,7 @@ DmaTransferBytes (
   //
   // This will fire off the transfer.
   //
- #if defined (MDE_CPU_AARCH64) || defined (MDE_CPU_RISCV64)
+ #if defined (MDE_CPU_AARCH64) || defined (MDE_CPU_RISCV64) || defined 
(MDE_CPU_LOONGARCH64)
   MmioWrite64 (mFwCfgDmaAddress, SwapBytes64 ((UINT64)&Access));
  #else
   MmioWrite32 ((UINT32)(mFwCfgDmaAddress + 4), SwapBytes32 ((UINT32)&Access));
@@ -365,7 +186,6 @@ DmaTransferBytes (
 /**
   Fast READ_BYTES_FUNCTION.
 **/
-STATIC
 VOID
 EFIAPI
 DmaReadBytes (
@@ -403,7 +223,6 @@ QemuFwCfgReadBytes (
 /**
   Slow WRITE_BYTES_FUNCTION.
 **/
-STATIC
 VOID
 EFIAPI
 MmioWriteBytes (
@@ -421,7 +240,6 @@ MmioWriteBytes (
 /**
   Fast WRITE_BYTES_FUNCTION.
 **/
-STATIC
 VOID
 EFIAPI
 DmaWriteBytes (
@@ -457,7 +275,6 @@ QemuFwCfgWriteBytes (
 /**
   Slow SKIP_BYTES_FUNCTION.
 **/
-STATIC
 VOID
 EFIAPI
 MmioSkipBytes (
@@ -484,7 +301,6 @@ MmioSkipBytes (
 /**
   Fast SKIP_BYTES_FUNCTION.
 **/
-STATIC
 VOID
 EFIAPI
 DmaSkipBytes (
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmio.inf 
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmio.inf
index 4b0dfbcb0d..f2596f270e 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmio.inf
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmio.inf
@@ -4,6 +4,7 @@
 #
 #  Copyright (C) 2013 - 2014, Red Hat, Inc.
 #  Copyright (c) 2008 - 2012, Intel Corporation. All rights reserved.<BR>
+#  Copyright (c) 2024 Loongson Technology Corporation Limited. All rights 
reserved.<BR>
 #
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
 #
@@ -23,11 +24,12 @@ [Defines]
 # The following information is for reference only and not required by the build
 # tools.
 #
-#  VALID_ARCHITECTURES           = ARM AARCH64 RISCV64
+#  VALID_ARCHITECTURES           = ARM AARCH64 RISCV64 LOONGARCH64
 #
 
 [Sources]
   QemuFwCfgLibMmio.c
+  QemuFwCfgMmioDxe.c
 
 [Packages]
   MdePkg/MdePkg.dec
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmioInternal.h 
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmioInternal.h
new file mode 100644
index 0000000000..d7d645f700
--- /dev/null
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmioInternal.h
@@ -0,0 +1,179 @@
+/** @file
+  Internal interfaces specific to the QemuFwCfgLibMmio instances in OvmfPkg.
+
+  Copyright (C) 2016, Red Hat, Inc.
+  Copyright (C) 2017, Advanced Micro Devices. All rights reserved
+  Copyright (c) 2024 Loongson Technology Corporation Limited. All rights 
reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef QEMU_FW_CFG_LIB_MMIO_INTERNAL_H_
+#define QEMU_FW_CFG_LIB_MMIO_INTERNAL_H_
+
+extern UINTN  mFwCfgSelectorAddress;
+extern UINTN  mFwCfgDataAddress;
+extern UINTN  mFwCfgDmaAddress;
+
+/**
+  Reads firmware configuration bytes into a buffer
+
+  @param[in] Size    Size in bytes to read
+  @param[in] Buffer  Buffer to store data into  (OPTIONAL if Size is 0)
+
+**/
+typedef
+VOID(EFIAPI READ_BYTES_FUNCTION)(
+  IN UINTN Size,
+  IN VOID  *Buffer OPTIONAL
+  );
+
+/**
+  Writes bytes from a buffer to firmware configuration
+
+  @param[in] Size    Size in bytes to write
+  @param[in] Buffer  Buffer to transfer data from (OPTIONAL if Size is 0)
+
+**/
+typedef
+VOID(EFIAPI WRITE_BYTES_FUNCTION)(
+  IN UINTN Size,
+  IN VOID  *Buffer OPTIONAL
+  );
+
+/**
+  Skips bytes in firmware configuration
+
+  @param[in] Size  Size in bytes to skip
+
+**/
+typedef
+VOID(EFIAPI SKIP_BYTES_FUNCTION)(
+  IN UINTN Size
+  );
+
+/**
+  Reads firmware configuration bytes into a buffer
+
+  @param[in] Size    Size in bytes to read
+  @param[in] Buffer  Buffer to store data into  (OPTIONAL if Size is 0)
+
+**/
+extern
+VOID
+EFIAPI
+(*InternalQemuFwCfgReadBytes) (
+  IN UINTN  Size,
+  IN VOID   *Buffer  OPTIONAL
+  );
+
+/**
+  Writes bytes from a buffer to firmware configuration
+
+  @param[in] Size    Size in bytes to write
+  @param[in] Buffer  Buffer to transfer data from (OPTIONAL if Size is 0)
+
+**/
+extern
+VOID
+EFIAPI
+(*InternalQemuFwCfgWriteBytes) (
+  IN UINTN  Size,
+  IN VOID   *Buffer  OPTIONAL
+  );
+
+/**
+  Skips bytes in firmware configuration
+
+  @param[in] Size  Size in bytes to skip
+
+**/
+extern
+VOID
+EFIAPI
+(*InternalQemuFwCfgSkipBytes) (
+  IN UINTN  Size
+  );
+
+/**
+  Slow READ_BYTES_FUNCTION.
+**/
+VOID
+EFIAPI
+MmioReadBytes (
+  IN UINTN  Size,
+  IN VOID   *Buffer OPTIONAL
+  );
+
+/**
+  Slow WRITE_BYTES_FUNCTION.
+**/
+VOID
+EFIAPI
+MmioWriteBytes (
+  IN UINTN  Size,
+  IN VOID   *Buffer OPTIONAL
+  );
+
+/**
+  Slow SKIP_BYTES_FUNCTION.
+**/
+VOID
+EFIAPI
+MmioSkipBytes (
+  IN UINTN  Size
+  );
+
+/**
+  Fast READ_BYTES_FUNCTION.
+**/
+VOID
+EFIAPI
+DmaReadBytes (
+  IN UINTN  Size,
+  IN VOID   *Buffer OPTIONAL
+  );
+
+/**
+  Fast WRITE_BYTES_FUNCTION.
+**/
+VOID
+EFIAPI
+DmaWriteBytes (
+  IN UINTN  Size,
+  IN VOID   *Buffer OPTIONAL
+  );
+
+/**
+  Fast SKIP_BYTES_FUNCTION.
+**/
+VOID
+EFIAPI
+DmaSkipBytes (
+  IN UINTN  Size
+  );
+
+/**
+  Transfer an array of bytes, or skip a number of bytes, using the DMA
+  interface.
+
+  @param[in]     Size     Size in bytes to transfer or skip.
+
+  @param[in,out] Buffer   Buffer to read data into or write data from. Ignored,
+                          and may be NULL, if Size is zero, or Control is
+                          FW_CFG_DMA_CTL_SKIP.
+
+  @param[in]     Control  One of the following:
+                          FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.
+                          FW_CFG_DMA_CTL_READ  - read from fw_cfg into Buffer.
+                          FW_CFG_DMA_CTL_SKIP  - skip bytes in fw_cfg.
+**/
+VOID
+DmaTransferBytes (
+  IN     UINTN   Size,
+  IN OUT VOID    *Buffer OPTIONAL,
+  IN     UINT32  Control
+  );
+
+#endif
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioDxe.c 
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioDxe.c
new file mode 100644
index 0000000000..4844a42a36
--- /dev/null
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioDxe.c
@@ -0,0 +1,153 @@
+/** @file
+
+  Stateful and implicitly initialized fw_cfg library implementation.
+
+  Copyright (C) 2013 - 2014, Red Hat, Inc.
+  Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>
+  (C) Copyright 2021 Hewlett Packard Enterprise Development LP<BR>
+  Copyright (c) 2024 Loongson Technology Corporation Limited. All rights 
reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Uefi.h>
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/QemuFwCfgLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+
+#include <Protocol/FdtClient.h>
+
+#include "QemuFwCfgLibMmioInternal.h"
+
+UINTN  mFwCfgSelectorAddress;
+UINTN  mFwCfgDataAddress;
+UINTN  mFwCfgDmaAddress;
+
+//
+// These correspond to the implementation we detect at runtime.
+//
+READ_BYTES_FUNCTION   *InternalQemuFwCfgReadBytes  = MmioReadBytes;
+WRITE_BYTES_FUNCTION  *InternalQemuFwCfgWriteBytes = MmioWriteBytes;
+SKIP_BYTES_FUNCTION   *InternalQemuFwCfgSkipBytes  = MmioSkipBytes;
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgInitialize (
+  VOID
+  )
+{
+  EFI_STATUS           Status;
+  FDT_CLIENT_PROTOCOL  *FdtClient;
+  CONST UINT64         *Reg;
+  UINT32               RegSize;
+  UINTN                AddressCells, SizeCells;
+  UINT64               FwCfgSelectorAddress;
+  UINT64               FwCfgSelectorSize;
+  UINT64               FwCfgDataAddress;
+  UINT64               FwCfgDataSize;
+  UINT64               FwCfgDmaAddress;
+  UINT64               FwCfgDmaSize;
+
+  Status = gBS->LocateProtocol (
+                  &gFdtClientProtocolGuid,
+                  NULL,
+                  (VOID **)&FdtClient
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  Status = FdtClient->FindCompatibleNodeReg (
+                        FdtClient,
+                        "qemu,fw-cfg-mmio",
+                        (CONST VOID **)&Reg,
+                        &AddressCells,
+                        &SizeCells,
+                        &RegSize
+                        );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((
+      DEBUG_WARN,
+      "%a: No 'qemu,fw-cfg-mmio' compatible DT node found (Status == %r)\n",
+      __func__,
+      Status
+      ));
+    return EFI_SUCCESS;
+  }
+
+  ASSERT (AddressCells == 2);
+  ASSERT (SizeCells == 2);
+  ASSERT (RegSize == 2 * sizeof (UINT64));
+
+  FwCfgDataAddress     = SwapBytes64 (Reg[0]);
+  FwCfgDataSize        = 8;
+  FwCfgSelectorAddress = FwCfgDataAddress + FwCfgDataSize;
+  FwCfgSelectorSize    = 2;
+
+  //
+  // The following ASSERT()s express
+  //
+  //   Address + Size - 1 <= MAX_UINTN
+  //
+  // for both registers, that is, that the last byte in each MMIO range is
+  // expressible as a MAX_UINTN. The form below is mathematically
+  // equivalent, and it also prevents any unsigned overflow before the
+  // comparison.
+  //
+  ASSERT (FwCfgSelectorAddress <= MAX_UINTN - FwCfgSelectorSize + 1);
+  ASSERT (FwCfgDataAddress     <= MAX_UINTN - FwCfgDataSize     + 1);
+
+  mFwCfgSelectorAddress = FwCfgSelectorAddress;
+  mFwCfgDataAddress     = FwCfgDataAddress;
+
+  DEBUG ((
+    DEBUG_INFO,
+    "Found FwCfg @ 0x%Lx/0x%Lx\n",
+    FwCfgSelectorAddress,
+    FwCfgDataAddress
+    ));
+
+  if (SwapBytes64 (Reg[1]) >= 0x18) {
+    FwCfgDmaAddress = FwCfgDataAddress + 0x10;
+    FwCfgDmaSize    = 0x08;
+
+    //
+    // See explanation above.
+    //
+    ASSERT (FwCfgDmaAddress <= MAX_UINTN - FwCfgDmaSize + 1);
+
+    DEBUG ((DEBUG_INFO, "Found FwCfg DMA @ 0x%Lx\n", FwCfgDmaAddress));
+  } else {
+    FwCfgDmaAddress = 0;
+  }
+
+  if (QemuFwCfgIsAvailable ()) {
+    UINT32  Signature;
+
+    QemuFwCfgSelectItem (QemuFwCfgItemSignature);
+    Signature = QemuFwCfgRead32 ();
+    if (Signature == SIGNATURE_32 ('Q', 'E', 'M', 'U')) {
+      //
+      // For DMA support, we require the DTB to advertise the register, and the
+      // feature bitmap (which we read without DMA) to confirm the feature.
+      //
+      if (FwCfgDmaAddress != 0) {
+        UINT32  Features;
+
+        QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);
+        Features = QemuFwCfgRead32 ();
+        if ((Features & FW_CFG_F_DMA) != 0) {
+          mFwCfgDmaAddress            = FwCfgDmaAddress;
+          InternalQemuFwCfgReadBytes  = DmaReadBytes;
+          InternalQemuFwCfgWriteBytes = DmaWriteBytes;
+          InternalQemuFwCfgSkipBytes  = DmaSkipBytes;
+        }
+      }
+    } else {
+      mFwCfgSelectorAddress = 0;
+      mFwCfgDataAddress     = 0;
+    }
+  }
+
+  return RETURN_SUCCESS;
+}
-- 
2.27.0



-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#118256): https://edk2.groups.io/g/devel/message/118256
Mute This Topic: https://groups.io/mt/105724968/21656
Group Owner: devel+ow...@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com]
-=-=-=-=-=-=-=-=-=-=-=-


Reply via email to