diff options
Diffstat (limited to 'OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioDxe.c')
| -rw-r--r-- | OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioDxe.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioDxe.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgMmioDxe.c new file mode 100644 index 0000000..0536253 --- /dev/null +++ b/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;
+}
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