Re: [PATCH edk2-platforms 08/12] Hisilicon: add PciCpuIo2Dxe

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 21 March 2018 at 01:03, Heyi Guo <heyi.guo@linaro.org> wrote:
> This is to prepare for switching to generic PciHostBridge, and
> CpuIo2Dxe is needed by generic PciHostBridge driver.
>
> The driver is copied from ArmPkg/Drivers/ArmPciCpuIo2Dxe and changed
> for D0x.
>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> ---
>  Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.inf |  48 ++
>  Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.c   | 557 ++++++++++++++++++++
>  2 files changed, 605 insertions(+)
>
> diff --git a/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.inf b/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.inf
> new file mode 100644
> index 000000000000..fbb28319ca87
> --- /dev/null
> +++ b/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.inf
> @@ -0,0 +1,48 @@
> +## @file
> +#  Produces the CPU I/O 2 Protocol by using the services of the I/O Library.
> +#
> +# Copyright (c) 2009 - 2014, Intel Corporation. All rights reserved.<BR>
> +# Copyright (c) 2016 - 2018, Linaro Ltd. All rights reserved.<BR>
> +# Copyright (c) 2018, Hisilicon Ltd. All rights reserved.<BR>
> +#
> +# This program and the accompanying materials
> +# are licensed and made available under the terms and conditions of the BSD License
> +# which accompanies this distribution.  The full text of the license may be found at
> +# http://opensource.org/licenses/bsd-license.php
> +#
> +# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x0001001A
> +  BASE_NAME                      = ArmPciCpuIo2Dxe
> +  FILE_GUID                      = 94577c7e-0bce-11e8-b4e8-286ed489ee9b
> +  MODULE_TYPE                    = DXE_DRIVER
> +  VERSION_STRING                 = 1.0
> +  ENTRY_POINT                    = ArmPciCpuIo2Initialize
> +
> +#
> +# The following information is for reference only and not required by the build tools.
> +#
> +#  VALID_ARCHITECTURES           = ARM AARCH64
> +#
> +
> +[Sources]
> +  ArmPciCpuIo2Dxe.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +
> +[LibraryClasses]
> +  UefiDriverEntryPoint
> +  BaseLib
> +  DebugLib
> +  IoLib
> +
> +[Protocols]
> +  gEfiCpuIo2ProtocolGuid                         ## PRODUCES
> +
> +[Depex]
> +  TRUE
> diff --git a/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.c b/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.c
> new file mode 100644
> index 000000000000..8426c5935c8a
> --- /dev/null
> +++ b/Silicon/Hisilicon/Drivers/ArmPciCpuIo2Dxe/ArmPciCpuIo2Dxe.c
> @@ -0,0 +1,557 @@
> +/** @file
> +  Produces the CPU I/O 2 Protocol.
> +
> +Copyright (c) 2009 - 2012, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) 2016 - 2018, Linaro Ltd. All rights reserved.<BR>
> +Copyright (c) 2018, Hisilicon Ltd. All rights reserved.<BR>
> +
> +This program and the accompanying materials
> +are licensed and made available under the terms and conditions of the BSD License
> +which accompanies this distribution.  The full text of the license may be found at
> +http://opensource.org/licenses/bsd-license.php
> +
> +THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +
> +**/
> +
> +#include <PiDxe.h>
> +
> +#include <Protocol/CpuIo2.h>
> +
> +#include <Library/BaseLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/IoLib.h>
> +#include <Library/PcdLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +
> +// The translated IO PORT address is already a MMIO address, so we make it the
> +// same as memory address for range check.
> +#define MAX_IO_PORT_ADDRESS   MAX_ADDRESS
> +
> +//
> +// Lookup table for increment values based on transfer widths
> +//
> +STATIC CONST UINT8 mInStride[] = {
> +  1, // EfiCpuIoWidthUint8
> +  2, // EfiCpuIoWidthUint16
> +  4, // EfiCpuIoWidthUint32
> +  8, // EfiCpuIoWidthUint64
> +  0, // EfiCpuIoWidthFifoUint8
> +  0, // EfiCpuIoWidthFifoUint16
> +  0, // EfiCpuIoWidthFifoUint32
> +  0, // EfiCpuIoWidthFifoUint64
> +  1, // EfiCpuIoWidthFillUint8
> +  2, // EfiCpuIoWidthFillUint16
> +  4, // EfiCpuIoWidthFillUint32
> +  8  // EfiCpuIoWidthFillUint64
> +};
> +
> +//
> +// Lookup table for increment values based on transfer widths
> +//
> +STATIC CONST UINT8 mOutStride[] = {
> +  1, // EfiCpuIoWidthUint8
> +  2, // EfiCpuIoWidthUint16
> +  4, // EfiCpuIoWidthUint32
> +  8, // EfiCpuIoWidthUint64
> +  1, // EfiCpuIoWidthFifoUint8
> +  2, // EfiCpuIoWidthFifoUint16
> +  4, // EfiCpuIoWidthFifoUint32
> +  8, // EfiCpuIoWidthFifoUint64
> +  0, // EfiCpuIoWidthFillUint8
> +  0, // EfiCpuIoWidthFillUint16
> +  0, // EfiCpuIoWidthFillUint32
> +  0  // EfiCpuIoWidthFillUint64
> +};
> +
> +/**
> +  Check parameters to a CPU I/O 2 Protocol service request.
> +
> +  The I/O operations are carried out exactly as requested. The caller is responsible
> +  for satisfying any alignment and I/O width restrictions that a PI System on a
> +  platform might require. For example on some platforms, width requests of
> +  EfiCpuIoWidthUint64 do not work. Misaligned buffers, on the other hand, will
> +  be handled by the driver.
> +
> +  @param[in] MmioOperation  TRUE for an MMIO operation, FALSE for I/O Port operation.
> +  @param[in] Width          Signifies the width of the I/O or Memory operation.
> +  @param[in] Address        The base address of the I/O operation.
> +  @param[in] Count          The number of I/O operations to perform. The number of
> +                            bytes moved is Width size * Count, starting at Address.
> +  @param[in] Buffer         For read operations, the destination buffer to store the results.
> +                            For write operations, the source buffer from which to write data.
> +
> +  @retval EFI_SUCCESS            The parameters for this request pass the checks.
> +  @retval EFI_INVALID_PARAMETER  Width is invalid for this PI system.
> +  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
> +  @retval EFI_UNSUPPORTED        The Buffer is not aligned for the given Width.
> +  @retval EFI_UNSUPPORTED        The address range specified by Address, Width,
> +                                 and Count is not valid for this PI system.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +CpuIoCheckParameter (
> +  IN BOOLEAN                    MmioOperation,
> +  IN EFI_CPU_IO_PROTOCOL_WIDTH  Width,
> +  IN UINT64                     Address,
> +  IN UINTN                      Count,
> +  IN VOID                       *Buffer
> +  )
> +{
> +  UINT64  MaxCount;
> +  UINT64  Limit;
> +
> +  //
> +  // Check to see if Buffer is NULL
> +  //
> +  if (Buffer == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Check to see if Width is in the valid range
> +  //
> +  if ((UINT32)Width >= EfiCpuIoWidthMaximum) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // For FIFO type, the target address won't increase during the access,
> +  // so treat Count as 1
> +  //
> +  if (Width >= EfiCpuIoWidthFifoUint8 && Width <= EfiCpuIoWidthFifoUint64) {
> +    Count = 1;
> +  }
> +
> +  //
> +  // Check to see if Width is in the valid range for I/O Port operations
> +  //
> +  Width = (EFI_CPU_IO_PROTOCOL_WIDTH) (Width & 0x03);
> +  if (!MmioOperation && (Width == EfiCpuIoWidthUint64)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Check to see if Address is aligned
> +  //
> +  if ((Address & (UINT64)(mInStride[Width] - 1)) != 0) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  //
> +  // Check to see if any address associated with this transfer exceeds the maximum
> +  // allowed address.  The maximum address implied by the parameters passed in is
> +  // Address + Size * Count.  If the following condition is met, then the transfer
> +  // is not supported.
> +  //
> +  //    Address + Size * Count > (MmioOperation ? MAX_ADDRESS : MAX_IO_PORT_ADDRESS) + 1
> +  //
> +  // Since MAX_ADDRESS can be the maximum integer value supported by the CPU and Count
> +  // can also be the maximum integer value supported by the CPU, this range
> +  // check must be adjusted to avoid all oveflow conditions.
> +  //
> +  // The following form of the range check is equivalent but assumes that
> +  // MAX_ADDRESS and MAX_IO_PORT_ADDRESS are of the form (2^n - 1).
> +  //
> +  Limit = (MmioOperation ? MAX_ADDRESS : MAX_IO_PORT_ADDRESS);
> +  if (Count == 0) {
> +    if (Address > Limit) {
> +      return EFI_UNSUPPORTED;
> +    }
> +  } else {
> +    MaxCount = RShiftU64 (Limit, Width);
> +    if (MaxCount < (Count - 1)) {
> +      return EFI_UNSUPPORTED;
> +    }
> +    if (Address > LShiftU64 (MaxCount - Count + 1, Width)) {
> +      return EFI_UNSUPPORTED;
> +    }
> +  }
> +
> +  //
> +  // Check to see if Buffer is aligned
> +  //
> +  if (((UINTN)Buffer & ((MIN (sizeof (UINTN), mInStride[Width])  - 1))) != 0) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Reads memory-mapped registers.
> +
> +  The I/O operations are carried out exactly as requested. The caller is responsible
> +  for satisfying any alignment and I/O width restrictions that a PI System on a
> +  platform might require. For example on some platforms, width requests of
> +  EfiCpuIoWidthUint64 do not work. Misaligned buffers, on the other hand, will
> +  be handled by the driver.
> +
> +  If Width is EfiCpuIoWidthUint8, EfiCpuIoWidthUint16, EfiCpuIoWidthUint32,
> +  or EfiCpuIoWidthUint64, then both Address and Buffer are incremented for
> +  each of the Count operations that is performed.
> +
> +  If Width is EfiCpuIoWidthFifoUint8, EfiCpuIoWidthFifoUint16,
> +  EfiCpuIoWidthFifoUint32, or EfiCpuIoWidthFifoUint64, then only Buffer is
> +  incremented for each of the Count operations that is performed. The read or
> +  write operation is performed Count times on the same Address.
> +
> +  If Width is EfiCpuIoWidthFillUint8, EfiCpuIoWidthFillUint16,
> +  EfiCpuIoWidthFillUint32, or EfiCpuIoWidthFillUint64, then only Address is
> +  incremented for each of the Count operations that is performed. The read or
> +  write operation is performed Count times from the first element of Buffer.
> +
> +  @param[in]  This     A pointer to the EFI_CPU_IO2_PROTOCOL instance.
> +  @param[in]  Width    Signifies the width of the I/O or Memory operation.
> +  @param[in]  Address  The base address of the I/O operation.
> +  @param[in]  Count    The number of I/O operations to perform. The number of
> +                       bytes moved is Width size * Count, starting at Address.
> +  @param[out] Buffer   For read operations, the destination buffer to store the results.
> +                       For write operations, the source buffer from which to write data.
> +
> +  @retval EFI_SUCCESS            The data was read from or written to the PI system.
> +  @retval EFI_INVALID_PARAMETER  Width is invalid for this PI system.
> +  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
> +  @retval EFI_UNSUPPORTED        The Buffer is not aligned for the given Width.
> +  @retval EFI_UNSUPPORTED        The address range specified by Address, Width,
> +                                 and Count is not valid for this PI system.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +CpuMemoryServiceRead (
> +  IN  EFI_CPU_IO2_PROTOCOL       *This,
> +  IN  EFI_CPU_IO_PROTOCOL_WIDTH  Width,
> +  IN  UINT64                     Address,
> +  IN  UINTN                      Count,
> +  OUT VOID                       *Buffer
> +  )
> +{
> +  EFI_STATUS                 Status;
> +  UINT8                      InStride;
> +  UINT8                      OutStride;
> +  EFI_CPU_IO_PROTOCOL_WIDTH  OperationWidth;
> +  UINT8                      *Uint8Buffer;
> +
> +  Status = CpuIoCheckParameter (TRUE, Width, Address, Count, Buffer);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  //
> +  // Select loop based on the width of the transfer
> +  //
> +  InStride = mInStride[Width];
> +  OutStride = mOutStride[Width];
> +  OperationWidth = (EFI_CPU_IO_PROTOCOL_WIDTH) (Width & 0x03);
> +  for (Uint8Buffer = Buffer; Count > 0; Address += InStride, Uint8Buffer += OutStride, Count--) {
> +    if (OperationWidth == EfiCpuIoWidthUint8) {
> +      *Uint8Buffer = MmioRead8 ((UINTN)Address);
> +    } else if (OperationWidth == EfiCpuIoWidthUint16) {
> +      *((UINT16 *)Uint8Buffer) = MmioRead16 ((UINTN)Address);
> +    } else if (OperationWidth == EfiCpuIoWidthUint32) {
> +      *((UINT32 *)Uint8Buffer) = MmioRead32 ((UINTN)Address);
> +    } else if (OperationWidth == EfiCpuIoWidthUint64) {
> +      *((UINT64 *)Uint8Buffer) = MmioRead64 ((UINTN)Address);
> +    }
> +  }
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Writes memory-mapped registers.
> +
> +  The I/O operations are carried out exactly as requested. The caller is responsible
> +  for satisfying any alignment and I/O width restrictions that a PI System on a
> +  platform might require. For example on some platforms, width requests of
> +  EfiCpuIoWidthUint64 do not work. Misaligned buffers, on the other hand, will
> +  be handled by the driver.
> +
> +  If Width is EfiCpuIoWidthUint8, EfiCpuIoWidthUint16, EfiCpuIoWidthUint32,
> +  or EfiCpuIoWidthUint64, then both Address and Buffer are incremented for
> +  each of the Count operations that is performed.
> +
> +  If Width is EfiCpuIoWidthFifoUint8, EfiCpuIoWidthFifoUint16,
> +  EfiCpuIoWidthFifoUint32, or EfiCpuIoWidthFifoUint64, then only Buffer is
> +  incremented for each of the Count operations that is performed. The read or
> +  write operation is performed Count times on the same Address.
> +
> +  If Width is EfiCpuIoWidthFillUint8, EfiCpuIoWidthFillUint16,
> +  EfiCpuIoWidthFillUint32, or EfiCpuIoWidthFillUint64, then only Address is
> +  incremented for each of the Count operations that is performed. The read or
> +  write operation is performed Count times from the first element of Buffer.
> +
> +  @param[in]  This     A pointer to the EFI_CPU_IO2_PROTOCOL instance.
> +  @param[in]  Width    Signifies the width of the I/O or Memory operation.
> +  @param[in]  Address  The base address of the I/O operation.
> +  @param[in]  Count    The number of I/O operations to perform. The number of
> +                       bytes moved is Width size * Count, starting at Address.
> +  @param[in]  Buffer   For read operations, the destination buffer to store the results.
> +                       For write operations, the source buffer from which to write data.
> +
> +  @retval EFI_SUCCESS            The data was read from or written to the PI system.
> +  @retval EFI_INVALID_PARAMETER  Width is invalid for this PI system.
> +  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
> +  @retval EFI_UNSUPPORTED        The Buffer is not aligned for the given Width.
> +  @retval EFI_UNSUPPORTED        The address range specified by Address, Width,
> +                                 and Count is not valid for this PI system.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +CpuMemoryServiceWrite (
> +  IN EFI_CPU_IO2_PROTOCOL       *This,
> +  IN EFI_CPU_IO_PROTOCOL_WIDTH  Width,
> +  IN UINT64                     Address,
> +  IN UINTN                      Count,
> +  IN VOID                       *Buffer
> +  )
> +{
> +  EFI_STATUS                 Status;
> +  UINT8                      InStride;
> +  UINT8                      OutStride;
> +  EFI_CPU_IO_PROTOCOL_WIDTH  OperationWidth;
> +  UINT8                      *Uint8Buffer;
> +
> +  Status = CpuIoCheckParameter (TRUE, Width, Address, Count, Buffer);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  //
> +  // Select loop based on the width of the transfer
> +  //
> +  InStride = mInStride[Width];
> +  OutStride = mOutStride[Width];
> +  OperationWidth = (EFI_CPU_IO_PROTOCOL_WIDTH) (Width & 0x03);
> +  for (Uint8Buffer = Buffer; Count > 0; Address += InStride, Uint8Buffer += OutStride, Count--) {
> +    if (OperationWidth == EfiCpuIoWidthUint8) {
> +      MmioWrite8 ((UINTN)Address, *Uint8Buffer);
> +    } else if (OperationWidth == EfiCpuIoWidthUint16) {
> +      MmioWrite16 ((UINTN)Address, *((UINT16 *)Uint8Buffer));
> +    } else if (OperationWidth == EfiCpuIoWidthUint32) {
> +      MmioWrite32 ((UINTN)Address, *((UINT32 *)Uint8Buffer));
> +    } else if (OperationWidth == EfiCpuIoWidthUint64) {
> +      MmioWrite64 ((UINTN)Address, *((UINT64 *)Uint8Buffer));
> +    }
> +  }
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Reads I/O registers.
> +
> +  The I/O operations are carried out exactly as requested. The caller is responsible
> +  for satisfying any alignment and I/O width restrictions that a PI System on a
> +  platform might require. For example on some platforms, width requests of
> +  EfiCpuIoWidthUint64 do not work. Misaligned buffers, on the other hand, will
> +  be handled by the driver.
> +
> +  If Width is EfiCpuIoWidthUint8, EfiCpuIoWidthUint16, EfiCpuIoWidthUint32,
> +  or EfiCpuIoWidthUint64, then both Address and Buffer are incremented for
> +  each of the Count operations that is performed.
> +
> +  If Width is EfiCpuIoWidthFifoUint8, EfiCpuIoWidthFifoUint16,
> +  EfiCpuIoWidthFifoUint32, or EfiCpuIoWidthFifoUint64, then only Buffer is
> +  incremented for each of the Count operations that is performed. The read or
> +  write operation is performed Count times on the same Address.
> +
> +  If Width is EfiCpuIoWidthFillUint8, EfiCpuIoWidthFillUint16,
> +  EfiCpuIoWidthFillUint32, or EfiCpuIoWidthFillUint64, then only Address is
> +  incremented for each of the Count operations that is performed. The read or
> +  write operation is performed Count times from the first element of Buffer.
> +
> +  @param[in]  This     A pointer to the EFI_CPU_IO2_PROTOCOL instance.
> +  @param[in]  Width    Signifies the width of the I/O or Memory operation.
> +  @param[in]  Address  The base address of the I/O operation.
> +  @param[in]  Count    The number of I/O operations to perform. The number of
> +                       bytes moved is Width size * Count, starting at Address.
> +  @param[out] Buffer   For read operations, the destination buffer to store the results.
> +                       For write operations, the source buffer from which to write data.
> +
> +  @retval EFI_SUCCESS            The data was read from or written to the PI system.
> +  @retval EFI_INVALID_PARAMETER  Width is invalid for this PI system.
> +  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
> +  @retval EFI_UNSUPPORTED        The Buffer is not aligned for the given Width.
> +  @retval EFI_UNSUPPORTED        The address range specified by Address, Width,
> +                                 and Count is not valid for this PI system.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +CpuIoServiceRead (
> +  IN  EFI_CPU_IO2_PROTOCOL       *This,
> +  IN  EFI_CPU_IO_PROTOCOL_WIDTH  Width,
> +  IN  UINT64                     Address,
> +  IN  UINTN                      Count,
> +  OUT VOID                       *Buffer
> +  )
> +{
> +  EFI_STATUS                 Status;
> +  UINT8                      InStride;
> +  UINT8                      OutStride;
> +  EFI_CPU_IO_PROTOCOL_WIDTH  OperationWidth;
> +  UINT8                      *Uint8Buffer;
> +
> +  Status = CpuIoCheckParameter (FALSE, Width, Address, Count, Buffer);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  //
> +  // Select loop based on the width of the transfer
> +  //
> +  InStride = mInStride[Width];
> +  OutStride = mOutStride[Width];
> +  OperationWidth = (EFI_CPU_IO_PROTOCOL_WIDTH) (Width & 0x03);
> +
> +  // Assuming address has already been translated into MMIO address by PCI host
> +  // bridge driver, so we call MmioRead/Write directly.

As noted in the previous patch, this is not correct.

This is where the type translation should occur, from I/O address in
the CPU view to an address covered by the I/O host bridge window that
translates to I/O TLPs on the PCI side.


> +  for (Uint8Buffer = Buffer; Count > 0; Address += InStride, Uint8Buffer += OutStride, Count--) {
> +    if (OperationWidth == EfiCpuIoWidthUint8) {
> +      *Uint8Buffer = MmioRead8 ((UINTN)Address);
> +    } else if (OperationWidth == EfiCpuIoWidthUint16) {
> +      *((UINT16 *)Uint8Buffer) = MmioRead16 ((UINTN)Address);
> +    } else if (OperationWidth == EfiCpuIoWidthUint32) {
> +      *((UINT32 *)Uint8Buffer) = MmioRead32 ((UINTN)Address);
> +    }
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Write I/O registers.
> +
> +  The I/O operations are carried out exactly as requested. The caller is responsible
> +  for satisfying any alignment and I/O width restrictions that a PI System on a
> +  platform might require. For example on some platforms, width requests of
> +  EfiCpuIoWidthUint64 do not work. Misaligned buffers, on the other hand, will
> +  be handled by the driver.
> +
> +  If Width is EfiCpuIoWidthUint8, EfiCpuIoWidthUint16, EfiCpuIoWidthUint32,
> +  or EfiCpuIoWidthUint64, then both Address and Buffer are incremented for
> +  each of the Count operations that is performed.
> +
> +  If Width is EfiCpuIoWidthFifoUint8, EfiCpuIoWidthFifoUint16,
> +  EfiCpuIoWidthFifoUint32, or EfiCpuIoWidthFifoUint64, then only Buffer is
> +  incremented for each of the Count operations that is performed. The read or
> +  write operation is performed Count times on the same Address.
> +
> +  If Width is EfiCpuIoWidthFillUint8, EfiCpuIoWidthFillUint16,
> +  EfiCpuIoWidthFillUint32, or EfiCpuIoWidthFillUint64, then only Address is
> +  incremented for each of the Count operations that is performed. The read or
> +  write operation is performed Count times from the first element of Buffer.
> +
> +  @param[in]  This     A pointer to the EFI_CPU_IO2_PROTOCOL instance.
> +  @param[in]  Width    Signifies the width of the I/O or Memory operation.
> +  @param[in]  Address  The base address of the I/O operation.
> +  @param[in]  Count    The number of I/O operations to perform. The number of
> +                       bytes moved is Width size * Count, starting at Address.
> +  @param[in]  Buffer   For read operations, the destination buffer to store the results.
> +                       For write operations, the source buffer from which to write data.
> +
> +  @retval EFI_SUCCESS            The data was read from or written to the PI system.
> +  @retval EFI_INVALID_PARAMETER  Width is invalid for this PI system.
> +  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
> +  @retval EFI_UNSUPPORTED        The Buffer is not aligned for the given Width.
> +  @retval EFI_UNSUPPORTED        The address range specified by Address, Width,
> +                                 and Count is not valid for this PI system.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +CpuIoServiceWrite (
> +  IN EFI_CPU_IO2_PROTOCOL       *This,
> +  IN EFI_CPU_IO_PROTOCOL_WIDTH  Width,
> +  IN UINT64                     Address,
> +  IN UINTN                      Count,
> +  IN VOID                       *Buffer
> +  )
> +{
> +  EFI_STATUS                 Status;
> +  UINT8                      InStride;
> +  UINT8                      OutStride;
> +  EFI_CPU_IO_PROTOCOL_WIDTH  OperationWidth;
> +  UINT8                      *Uint8Buffer;
> +
> +  //
> +  // Make sure the parameters are valid
> +  //
> +  Status = CpuIoCheckParameter (FALSE, Width, Address, Count, Buffer);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  //
> +  // Select loop based on the width of the transfer
> +  //
> +  InStride = mInStride[Width];
> +  OutStride = mOutStride[Width];
> +  OperationWidth = (EFI_CPU_IO_PROTOCOL_WIDTH) (Width & 0x03);
> +
> +  // Assuming address has already been translated into MMIO address by PCI host
> +  // bridge driver, so we call MmioRead/Write directly.
> +  for (Uint8Buffer = (UINT8 *)Buffer; Count > 0; Address += InStride, Uint8Buffer += OutStride, Count--) {
> +    if (OperationWidth == EfiCpuIoWidthUint8) {
> +      MmioWrite8 ((UINTN)Address, *Uint8Buffer);
> +    } else if (OperationWidth == EfiCpuIoWidthUint16) {
> +      MmioWrite16 ((UINTN)Address, *((UINT16 *)Uint8Buffer));
> +    } else if (OperationWidth == EfiCpuIoWidthUint32) {
> +      MmioWrite32 ((UINTN)Address, *((UINT32 *)Uint8Buffer));
> +    }
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +//
> +// CPU I/O 2 Protocol instance
> +//
> +STATIC EFI_CPU_IO2_PROTOCOL mCpuIo2 = {
> +  {
> +    CpuMemoryServiceRead,
> +    CpuMemoryServiceWrite
> +  },
> +  {
> +    CpuIoServiceRead,
> +    CpuIoServiceWrite
> +  }
> +};
> +
> +
> +/**
> +  The user Entry Point for module CpuIo2Dxe. The user code starts with this function.
> +
> +  @param[in] ImageHandle    The firmware allocated handle for the EFI image.
> +  @param[in] SystemTable    A pointer to the EFI System Table.
> +
> +  @retval EFI_SUCCESS       The entry point is executed successfully.
> +  @retval other             Some error occurs when executing this entry point.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +ArmPciCpuIo2Initialize (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  EFI_STATUS Status;
> +
> +  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiCpuIo2ProtocolGuid);
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +                  &ImageHandle,
> +                  &gEfiCpuIo2ProtocolGuid, &mCpuIo2,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  return Status;
> +}
> --
> 2.7.4
>