On Thu, 25 Apr 2024 at 14:13, Chao Li <lic...@loongson.cn> wrote:
>
> 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>
>
Please only claim copyright for code that you wrote, not for code that
you just moved between files.
> 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;
> +
These can remain STATIC and live in the DXE version of the library, no?
> +/**
> + 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;
> +
These are duplicated later in the PEI version of the library, right?
So they can live in the shared .c file
> +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
>
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