OvmfPkg: Separate QemuFwCfgLibMmio.c into two files

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

Some DXE stage variables became non-static in this patch, they will be
restored to static in the next patch.

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

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>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Cc: Sunil V L <sunilvl@ventanamicro.com>
Cc: Andrei Warkentin <andrei.warkentin@intel.com>
Signed-off-by: Chao Li <lichao@loongson.cn>

OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioDxe.c

@@ -0,0 +1,145 @@
+/** @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>
+
+  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;
+
+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;
+}