OvmfPkg: Add the QemuFwCfgMmioLib PEI stage version

Added the PEI stage library for QemuFwCfgMmioLib, which uses the FDT to
find the fw_cfg and parse it.

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

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Co-authored-by: Xianglai Li <lixianglai@loongson.cn>
Signed-off-by: Chao Li <lichao@loongson.cn>

OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioPei.c

@@ -0,0 +1,236 @@
+/** @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/IoLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/QemuFwCfgLib.h>
+
+#include <libfdt.h>
+
+#include "QemuFwCfgLibMmioInternal.h"
+
+/**
+  To get firmware configure selector address.
+
+  @param VOID
+
+  @retval  firmware configure selector address
+**/
+UINTN
+EFIAPI
+QemuGetFwCfgSelectorAddress (
+  VOID
+  )
+{
+  QEMU_FW_CFG_RESOURCE  *FwCfgResource;
+
+  FwCfgResource = QemuGetFwCfgResourceHob ();
+  ASSERT (FwCfgResource != NULL);
+
+  return FwCfgResource->FwCfgSelectorAddress;
+}
+
+/**
+  To get firmware configure Data address.
+
+  @param VOID
+
+  @retval  firmware configure data address
+**/
+UINTN
+EFIAPI
+QemuGetFwCfgDataAddress (
+  VOID
+  )
+{
+  QEMU_FW_CFG_RESOURCE  *FwCfgResource;
+
+  FwCfgResource = QemuGetFwCfgResourceHob ();
+  ASSERT (FwCfgResource != NULL);
+
+  return FwCfgResource->FwCfgDataAddress;
+}
+
+/**
+  To get firmware DMA address.
+
+  @param VOID
+
+  @retval  firmware DMA address
+**/
+UINTN
+EFIAPI
+QemuGetFwCfgDmaAddress (
+  VOID
+  )
+{
+  QEMU_FW_CFG_RESOURCE  *FwCfgResource;
+
+  FwCfgResource = QemuGetFwCfgResourceHob ();
+  ASSERT (FwCfgResource != NULL);
+
+  return FwCfgResource->FwCfgDmaAddress;
+}
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgInitialize (
+  VOID
+  )
+{
+  VOID                  *DeviceTreeBase;
+  INT32                 Node;
+  INT32                 Prev;
+  UINT32                Signature;
+  CONST CHAR8           *Type;
+  INT32                 Len;
+  CONST UINT64          *Reg;
+  UINT64                FwCfgSelectorAddress;
+  UINT64                FwCfgSelectorSize;
+  UINT64                FwCfgDataAddress;
+  UINT64                FwCfgDataSize;
+  UINT64                FwCfgDmaAddress;
+  UINT64                FwCfgDmaSize;
+  QEMU_FW_CFG_RESOURCE  *FwCfgResource;
+
+  //
+  // Check whether the Qemu firmware configure resources HOB has been created,
+  // if so use the resources in the HOB.
+  //
+  FwCfgResource = QemuGetFwCfgResourceHob ();
+  if (FwCfgResource != NULL) {
+    return RETURN_SUCCESS;
+  }
+
+  DeviceTreeBase = (VOID *)(UINTN)PcdGet64 (PcdDeviceTreeInitialBaseAddress);
+  ASSERT (DeviceTreeBase != NULL);
+  //
+  // Make sure we have a valid device tree blob
+  //
+  ASSERT (fdt_check_header (DeviceTreeBase) == 0);
+
+  //
+  // Create resouce memory
+  //
+  FwCfgResource = AllocateZeroPool (sizeof (QEMU_FW_CFG_RESOURCE));
+  ASSERT (FwCfgResource != NULL);
+
+  for (Prev = 0; ; Prev = Node) {
+    Node = fdt_next_node (DeviceTreeBase, Prev, NULL);
+    if (Node < 0) {
+      break;
+    }
+
+    //
+    // Check for memory node
+    //
+    Type = fdt_getprop (DeviceTreeBase, Node, "compatible", &Len);
+    if ((Type != NULL) &&
+        (AsciiStrnCmp (Type, "qemu,fw-cfg-mmio", Len) == 0))
+    {
+      //
+      // Get the 'reg' property of this node. For now, we will assume
+      // two 8 byte quantities for base and size, respectively.
+      //
+      Reg = fdt_getprop (DeviceTreeBase, Node, "reg", &Len);
+      if ((Reg != 0) && (Len == (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);
+
+        FwCfgResource->FwCfgSelectorAddress = FwCfgSelectorAddress;
+        FwCfgResource->FwCfgDataAddress     = 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));
+          FwCfgResource->FwCfgDmaAddress = FwCfgDmaAddress;
+        } else {
+          FwCfgDmaAddress = 0;
+        }
+
+        if ((FwCfgSelectorAddress != 0) && (FwCfgDataAddress != 0)) {
+          //
+          // Select Item Signature
+          //
+          MmioWrite16 (FwCfgSelectorAddress, SwapBytes16 ((UINT16)QemuFwCfgItemSignature));
+
+          //
+          // Readout the Signature.
+          //
+          Signature = MmioRead32 (FwCfgDataAddress);
+
+          if (Signature == SIGNATURE_32 ('Q', 'E', 'M', 'U')) {
+            //
+            // Build the firmware configure resource HOB.
+            //
+            QemuBuildFwCfgResourceHob (FwCfgResource);
+          } else {
+            FwCfgResource->FwCfgDataAddress     = 0;
+            FwCfgResource->FwCfgSelectorAddress = 0;
+            FwCfgResource->FwCfgDmaAddress      = 0;
+
+            DEBUG ((
+              DEBUG_ERROR,
+              "%a: Signature dose not match QEMU!\n",
+              __func__
+              ));
+            break;
+          }
+        }
+
+        break;
+      } else {
+        DEBUG ((
+          DEBUG_ERROR,
+          "%a: Failed to parse FDT QemuCfg node\n",
+          __func__
+          ));
+        break;
+      }
+    }
+  }
+
+  return RETURN_SUCCESS;
+}

OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioPeiLib.inf

@@ -0,0 +1,45 @@
+## @file
+#
+#  Stateful, implicitly initialized fw_cfg library.
+#
+#  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
+#
+##
+
+[Defines]
+  INF_VERSION                    = 1.29
+  BASE_NAME                      = QemuFwCfgPeiLib
+  FILE_GUID                      = CDF9A9D5-7422-4DCB-B41D-607151AD320B
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = QemuFwCfgLib|PEIM
+
+  CONSTRUCTOR                    = QemuFwCfgInitialize
+
+[Sources]
+  QemuFwCfgLibMmio.c
+  QemuFwCfgMmioPei.c
+
+[Packages]
+  EmbeddedPkg/EmbeddedPkg.dec
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  BaseLib
+  BaseMemoryLib
+  DebugLib
+  HobLib
+  IoLib
+  MemoryAllocationLib
+  PcdLib
+
+[Pcd]
+  gUefiOvmfPkgTokenSpaceGuid.PcdDeviceTreeInitialBaseAddress
+
+[Guids]
+  gQemuFirmwareResourceHobGuid