path: root/MdeModulePkg/Bus/Pci/EhciDxe/Ehci.c

/** @file

Copyright (c) 2006 - 2007, Intel Corporation
All rights reserved. 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.

Module Name:

    Ehci.c

Abstract:


Revision History

**/


#include "Ehci.h"

//
// Two arrays used to translate the EHCI port state (change)
// to the UEFI protocol's port state (change).
//
USB_PORT_STATE_MAP  mUsbPortStateMap[] = {
  {PORTSC_CONN,     USB_PORT_STAT_CONNECTION},
  {PORTSC_ENABLED,  USB_PORT_STAT_ENABLE},
  {PORTSC_SUSPEND,  USB_PORT_STAT_SUSPEND},
  {PORTSC_OVERCUR,  USB_PORT_STAT_OVERCURRENT},
  {PORTSC_RESET,    USB_PORT_STAT_RESET},
  {PORTSC_POWER,    USB_PORT_STAT_POWER},
  {PORTSC_OWNER,    USB_PORT_STAT_OWNER}
};

USB_PORT_STATE_MAP  mUsbPortChangeMap[] = {
  {PORTSC_CONN_CHANGE,    USB_PORT_STAT_C_CONNECTION},
  {PORTSC_ENABLE_CHANGE,  USB_PORT_STAT_C_ENABLE},
  {PORTSC_OVERCUR_CHANGE, USB_PORT_STAT_C_OVERCURRENT}
};


/**
  Retrieves the capablility of root hub ports.

  @param  This                 This EFI_USB_HC_PROTOCOL instance.
  @param  MaxSpeed             Max speed supported by the controller
  @param  PortNumber           Number of the root hub ports.
  @param  Is64BitCapable       Whether the controller supports 64-bit memory
                               addressing.

  @return EFI_SUCCESS           : host controller capability were retrieved successfully.
  @return EFI_INVALID_PARAMETER : Either of the three capability pointer is NULL

**/
STATIC
EFI_STATUS
EFIAPI
EhcGetCapability (
  IN  EFI_USB2_HC_PROTOCOL  *This,
  OUT UINT8                 *MaxSpeed,
  OUT UINT8                 *PortNumber,
  OUT UINT8                 *Is64BitCapable
  )
{
  USB2_HC_DEV             *Ehc;
  EFI_TPL                 OldTpl;

  if ((MaxSpeed == NULL) || (PortNumber == NULL) || (Is64BitCapable == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  OldTpl          = gBS->RaiseTPL (EHC_TPL);
  Ehc             = EHC_FROM_THIS (This);

  *MaxSpeed       = EFI_USB_SPEED_HIGH;
  *PortNumber     = (UINT8) (Ehc->HcStructParams & HCSP_NPORTS);
  *Is64BitCapable = (UINT8) (Ehc->HcCapParams & HCCP_64BIT);

  EHC_DEBUG (("EhcGetCapability: %d ports, 64 bit %d\n", *PortNumber, *Is64BitCapable));

  gBS->RestoreTPL (OldTpl);
  return EFI_SUCCESS;
}


/**
  Provides software reset for the USB host controller.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  Attributes           A bit mask of the reset operation to perform.

  @return EFI_SUCCESS           : The reset operation succeeded.
  @return EFI_INVALID_PARAMETER : Attributes is not valid.
  @return EFI_UNSUPPOURTED      : The type of reset specified by Attributes is
  @return not currently supported by the host controller.
  @return EFI_DEVICE_ERROR      : Host controller isn't halted to reset.

**/
STATIC
EFI_STATUS
EFIAPI
EhcReset (
  IN EFI_USB2_HC_PROTOCOL *This,
  IN UINT16               Attributes
  )
{
  USB2_HC_DEV             *Ehc;
  EFI_TPL                 OldTpl;
  EFI_STATUS              Status;

  OldTpl  = gBS->RaiseTPL (EHC_TPL);
  Ehc     = EHC_FROM_THIS (This);

  switch (Attributes) {
  case EFI_USB_HC_RESET_GLOBAL:
  //
  // Flow through, same behavior as Host Controller Reset
  //
  case EFI_USB_HC_RESET_HOST_CONTROLLER:
    //
    // Host Controller must be Halt when Reset it
    //
    if (!EhcIsHalt (Ehc)) {
      Status = EhcHaltHC (Ehc, EHC_GENERIC_TIMEOUT);

      if (EFI_ERROR (Status)) {
        Status = EFI_DEVICE_ERROR;
        goto ON_EXIT;
      }
    }
    
    //
    // Clean up the asynchronous transfers, currently only
    // interrupt supports asynchronous operation.
    //
    EhciDelAllAsyncIntTransfers (Ehc);
    EhcAckAllInterrupt (Ehc);
    EhcFreeSched (Ehc);

    Status = EhcResetHC (Ehc, EHC_RESET_TIMEOUT);

    if (EFI_ERROR (Status)) {
      goto ON_EXIT;
    }

    Status = EhcInitHC (Ehc);
    break;

  case EFI_USB_HC_RESET_GLOBAL_WITH_DEBUG:
  case EFI_USB_HC_RESET_HOST_WITH_DEBUG:
    Status = EFI_UNSUPPORTED;
    break;

  default:
    Status = EFI_INVALID_PARAMETER;
  }

ON_EXIT:
  EHC_DEBUG (("EhcReset: exit status %r\n", Status));
  gBS->RestoreTPL (OldTpl);
  return Status;
}


/**
  Retrieve the current state of the USB host controller.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  State                Variable to return the current host controller
                               state.

  @return EFI_SUCCESS           : Host controller state was returned in State.
  @return EFI_INVALID_PARAMETER : State is NULL.
  @return EFI_DEVICE_ERROR      : An error was encountered while attempting to
  @return retrieve the host controller's current state.

**/
STATIC
EFI_STATUS
EFIAPI
EhcGetState (
  IN  CONST EFI_USB2_HC_PROTOCOL  *This,
  OUT       EFI_USB_HC_STATE      *State
  )
{
  EFI_TPL                 OldTpl;
  USB2_HC_DEV             *Ehc;

  if (State == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  OldTpl  = gBS->RaiseTPL (EHC_TPL);
  Ehc     = EHC_FROM_THIS (This);

  if (EHC_REG_BIT_IS_SET (Ehc, EHC_USBSTS_OFFSET, USBSTS_HALT)) {
    *State = EfiUsbHcStateHalt;
  } else {
    *State = EfiUsbHcStateOperational;
  }

  gBS->RestoreTPL (OldTpl);

  EHC_DEBUG (("EhcGetState: current state %d\n", *State));
  return EFI_SUCCESS;
}


/**
  Sets the USB host controller to a specific state.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  State                The state of the host controller that will be set.

  @return EFI_SUCCESS           : The USB host controller was successfully placed
  @return in the state specified by State.
  @return EFI_INVALID_PARAMETER : State is invalid.
  @return EFI_DEVICE_ERROR      : Failed to set the state due to device error.

**/
STATIC
EFI_STATUS
EFIAPI
EhcSetState (
  IN EFI_USB2_HC_PROTOCOL *This,
  IN EFI_USB_HC_STATE     State
  )
{
  USB2_HC_DEV             *Ehc;
  EFI_TPL                 OldTpl;
  EFI_STATUS              Status;
  EFI_USB_HC_STATE        CurState;

  Status = EhcGetState (This, &CurState);

  if (EFI_ERROR (Status)) {
    return EFI_DEVICE_ERROR;
  }

  if (CurState == State) {
    return EFI_SUCCESS;
  }

  OldTpl  = gBS->RaiseTPL (EHC_TPL);
  Ehc     = EHC_FROM_THIS (This);

  switch (State) {
  case EfiUsbHcStateHalt:
    Status = EhcHaltHC (Ehc, EHC_GENERIC_TIMEOUT);
    break;

  case EfiUsbHcStateOperational:
    if (EHC_REG_BIT_IS_SET (Ehc, EHC_USBSTS_OFFSET, USBSTS_SYS_ERROR)) {
      Status = EFI_DEVICE_ERROR;
      break;
    }

    //
    // Software must not write a one to this field unless the host controller
    // is in the Halted state. Doing so will yield undefined results. 
    // refers to Spec[EHCI1.0-2.3.1]
    // 
    if (!EHC_REG_BIT_IS_SET (Ehc, EHC_USBSTS_OFFSET, USBSTS_HALT)) {
      Status = EFI_DEVICE_ERROR;
      break;
    }

    Status = EhcRunHC (Ehc, EHC_GENERIC_TIMEOUT);
    break;

  case EfiUsbHcStateSuspend:
    Status = EFI_UNSUPPORTED;
    break;

  default:
    Status = EFI_INVALID_PARAMETER;
  }

  EHC_DEBUG (("EhcSetState: exit status %r\n", Status));
  gBS->RestoreTPL (OldTpl);
  return Status;
}


/**
  Retrieves the current status of a USB root hub port.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  PortNumber           The root hub port to retrieve the state from.   This
                               value is zero-based.
  @param  PortStatus           Variable to receive the port state

  @return EFI_SUCCESS           : The status of the USB root hub port specified
  @return by PortNumber was returned in PortStatus.
  @return EFI_INVALID_PARAMETER : PortNumber is invalid.
  @return EFI_DEVICE_ERROR      : Can't read register

**/
STATIC
EFI_STATUS
EFIAPI
EhcGetRootHubPortStatus (
  IN  CONST EFI_USB2_HC_PROTOCOL  *This,
  IN  CONST UINT8                 PortNumber,
  OUT       EFI_USB_PORT_STATUS   *PortStatus
  )
{
  USB2_HC_DEV             *Ehc;
  EFI_TPL                 OldTpl;
  UINT32                  Offset;
  UINT32                  State;
  UINT32                  TotalPort;
  UINTN                   Index;
  UINTN                   MapSize;
  EFI_STATUS              Status;

  if (PortStatus == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  OldTpl    = gBS->RaiseTPL (EHC_TPL);

  Ehc       = EHC_FROM_THIS (This);
  Status    = EFI_SUCCESS;

  TotalPort = (Ehc->HcStructParams & HCSP_NPORTS);

  if (PortNumber >= TotalPort) {
    Status = EFI_INVALID_PARAMETER;
    goto ON_EXIT;
  }

  Offset                        = (UINT32) (EHC_PORT_STAT_OFFSET + (4 * PortNumber));
  PortStatus->PortStatus        = 0;
  PortStatus->PortChangeStatus  = 0;

  State                         = EhcReadOpReg (Ehc, Offset);

  //
  // Identify device speed. If in K state, it is low speed.
  // If the port is enabled after reset, the device is of
  // high speed. The USB bus driver should retrieve the actual
  // port speed after reset.
  //
  if (EHC_BIT_IS_SET (State, PORTSC_LINESTATE_K)) {
    PortStatus->PortStatus |= USB_PORT_STAT_LOW_SPEED;

  } else if (EHC_BIT_IS_SET (State, PORTSC_ENABLED)) {
    PortStatus->PortStatus |= USB_PORT_STAT_HIGH_SPEED;
  }

  //
  // Convert the EHCI port/port change state to UEFI status
  //
  MapSize = sizeof (mUsbPortStateMap) / sizeof (USB_PORT_STATE_MAP);

  for (Index = 0; Index < MapSize; Index++) {
    if (EHC_BIT_IS_SET (State, mUsbPortStateMap[Index].HwState)) {
      PortStatus->PortStatus = (UINT16) (PortStatus->PortStatus | mUsbPortStateMap[Index].UefiState);
    }
  }

  MapSize = sizeof (mUsbPortChangeMap) / sizeof (USB_PORT_STATE_MAP);

  for (Index = 0; Index < MapSize; Index++) {
    if (EHC_BIT_IS_SET (State, mUsbPortChangeMap[Index].HwState)) {
      PortStatus->PortChangeStatus = (UINT16) (PortStatus->PortChangeStatus | mUsbPortChangeMap[Index].UefiState);
    }
  }

ON_EXIT:
  gBS->RestoreTPL (OldTpl);
  return Status;
}


/**
  Sets a feature for the specified root hub port.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  PortNumber           Root hub port to set.
  @param  PortFeature          Feature to set

  @return EFI_SUCCESS           : The feature specified by PortFeature was set
  @return EFI_INVALID_PARAMETER : PortNumber is invalid or PortFeature is invalid.
  @return EFI_DEVICE_ERROR      : Can't read register

**/
STATIC
EFI_STATUS
EFIAPI
EhcSetRootHubPortFeature (
  IN  EFI_USB2_HC_PROTOCOL  *This,
  IN  UINT8                 PortNumber,
  IN  EFI_USB_PORT_FEATURE  PortFeature
  )
{
  USB2_HC_DEV             *Ehc;
  EFI_TPL                 OldTpl;
  UINT32                  Offset;
  UINT32                  State;
  UINT32                  TotalPort;
  EFI_STATUS              Status;

  OldTpl    = gBS->RaiseTPL (EHC_TPL);
  Ehc       = EHC_FROM_THIS (This);
  Status    = EFI_SUCCESS;

  TotalPort = (Ehc->HcStructParams & HCSP_NPORTS);

  if (PortNumber >= TotalPort) {
    Status = EFI_INVALID_PARAMETER;
    goto ON_EXIT;
  }

  Offset  = (UINT32) (EHC_PORT_STAT_OFFSET + (4 * PortNumber));
  State   = EhcReadOpReg (Ehc, Offset);

  //
  // Mask off the port status change bits, these bits are
  // write clean bit
  //
  State &= ~PORTSC_CHANGE_MASK;

  switch (PortFeature) {
  case EfiUsbPortEnable:
    //
    // Sofeware can't set this bit, Port can only be enable by
    // EHCI as a part of the reset and enable
    //
    State |= PORTSC_ENABLED;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  case EfiUsbPortSuspend:
    State |= PORTSC_SUSPEND;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  case EfiUsbPortReset:
    //
    // Make sure Host Controller not halt before reset it
    //
    if (EhcIsHalt (Ehc)) {
      Status = EhcRunHC (Ehc, EHC_GENERIC_TIMEOUT);

      if (EFI_ERROR (Status)) {
        EHC_DEBUG (("EhcSetRootHubPortFeature :failed to start HC - %r\n", Status));
        break;
      }
    }
    
    //
    // Set one to PortReset bit must also set zero to PortEnable bit
    //
    State |= PORTSC_RESET;
    State &= ~PORTSC_ENABLED;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  case EfiUsbPortPower:
    //
    // Not supported, ignore the operation
    //
    Status = EFI_SUCCESS;
    break;

  case EfiUsbPortOwner:
    State |= PORTSC_OWNER;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  default:
    Status = EFI_INVALID_PARAMETER;
  }

ON_EXIT:
  EHC_DEBUG (("EhcSetRootHubPortFeature: exit status %r\n", Status));

  gBS->RestoreTPL (OldTpl);
  return Status;
}


/**
  Clears a feature for the specified root hub port.

  @param  This                 A pointer to the EFI_USB2_HC_PROTOCOL instance.
  @param  PortNumber           Specifies the root hub port whose feature is
                               requested to be cleared.
  @param  PortFeature          Indicates the feature selector associated with the
                               feature clear request.

  @return EFI_SUCCESS           : The feature specified by PortFeature was cleared
  @return for the USB root hub port specified by PortNumber.
  @return EFI_INVALID_PARAMETER : PortNumber is invalid or PortFeature is invalid.
  @return EFI_DEVICE_ERROR      : Can't read register

**/
STATIC
EFI_STATUS
EFIAPI
EhcClearRootHubPortFeature (
  IN  EFI_USB2_HC_PROTOCOL  *This,
  IN  UINT8                 PortNumber,
  IN  EFI_USB_PORT_FEATURE  PortFeature
  )
{
  USB2_HC_DEV             *Ehc;
  EFI_TPL                 OldTpl;
  UINT32                  Offset;
  UINT32                  State;
  UINT32                  TotalPort;
  EFI_STATUS              Status;

  OldTpl    = gBS->RaiseTPL (EHC_TPL);
  Ehc       = EHC_FROM_THIS (This);
  Status    = EFI_SUCCESS;

  TotalPort = (Ehc->HcStructParams & HCSP_NPORTS);

  if (PortNumber >= TotalPort) {
    Status = EFI_INVALID_PARAMETER;
    goto ON_EXIT;
  }

  Offset  = EHC_PORT_STAT_OFFSET + (4 * PortNumber);
  State   = EhcReadOpReg (Ehc, Offset);
  State &= ~PORTSC_CHANGE_MASK;

  switch (PortFeature) {
  case EfiUsbPortEnable:
    //
    // Clear PORT_ENABLE feature means disable port.
    //
    State &= ~PORTSC_ENABLED;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  case EfiUsbPortSuspend:
    //
    // A write of zero to this bit is ignored by the host
    // controller. The host controller will unconditionally
    // set this bit to a zero when:
    //   1. software sets the Forct Port Resume bit to a zero from a one.
    //   2. software sets the Port Reset bit to a one frome a zero.
    //
    State &= ~PORSTSC_RESUME;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  case EfiUsbPortReset:
    //
    // Clear PORT_RESET means clear the reset signal.
    //
    State &= ~PORTSC_RESET;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  case EfiUsbPortOwner:
    //
    // Clear port owner means this port owned by EHC
    //
    State &= ~PORTSC_OWNER;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  case EfiUsbPortConnectChange:
    //
    // Clear connect status change
    //
    State |= PORTSC_CONN_CHANGE;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  case EfiUsbPortEnableChange:
    //
    // Clear enable status change
    //
    State |= PORTSC_ENABLE_CHANGE;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  case EfiUsbPortOverCurrentChange:
    //
    // Clear PortOverCurrent change
    //
    State |= PORTSC_OVERCUR_CHANGE;
    EhcWriteOpReg (Ehc, Offset, State);
    break;

  case EfiUsbPortPower:
  case EfiUsbPortSuspendChange:
  case EfiUsbPortResetChange:
    //
    // Not supported or not related operation
    //
    break;

  default:
    Status = EFI_INVALID_PARAMETER;
    break;
  }

ON_EXIT:
  EHC_DEBUG (("EhcClearRootHubPortFeature: exit status %r\n", Status));
  gBS->RestoreTPL (OldTpl);
  return Status;
}


/**
  Submits control transfer to a target USB device.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  DeviceAddress        The target device address
  @param  DeviceSpeed          Target device speed.
  @param  MaximumPacketLength  Maximum packet size the default control transfer
                               endpoint is capable of sending or receiving.
  @param  Request              USB device request to send
  @param  TransferDirection    Specifies the data direction for the data stage
  @param  Data                 Data buffer to be transmitted or received from USB
                               device.
  @param  DataLength           The size (in bytes) of the data buffer
  @param  TimeOut              Indicates the maximum timeout, in millisecond,
  @param  Translator           Transaction translator to be used by this device.
  @param  TransferResult       Return the result of this control transfer.

  @return EFI_SUCCESS           : Transfer was completed successfully.
  @return EFI_OUT_OF_RESOURCES  : The transfer failed due to lack of resources.
  @return EFI_INVALID_PARAMETER : Some parameters are invalid.
  @return EFI_TIMEOUT           : Transfer failed due to timeout.
  @return EFI_DEVICE_ERROR      : Transfer failed due to host controller or device error.

**/
STATIC
EFI_STATUS
EFIAPI
EhcControlTransfer (
  IN  EFI_USB2_HC_PROTOCOL                *This,
  IN  UINT8                               DeviceAddress,
  IN  UINT8                               DeviceSpeed,
  IN  UINTN                               MaximumPacketLength,
  IN  EFI_USB_DEVICE_REQUEST              *Request,
  IN  EFI_USB_DATA_DIRECTION              TransferDirection,
  IN  OUT VOID                            *Data,
  IN  OUT UINTN                           *DataLength,
  IN  UINTN                               TimeOut,
  IN  EFI_USB2_HC_TRANSACTION_TRANSLATOR  *Translator,
  OUT UINT32                              *TransferResult
  )
{
  USB2_HC_DEV             *Ehc;
  URB                     *Urb;
  EFI_TPL                 OldTpl;
  UINT8                   Endpoint;
  EFI_STATUS              Status;

  //
  // Validate parameters
  //
  if ((Request == NULL) || (TransferResult == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  if ((TransferDirection != EfiUsbDataIn) &&
      (TransferDirection != EfiUsbDataOut) &&
      (TransferDirection != EfiUsbNoData)) {
    return EFI_INVALID_PARAMETER;
  }

  if ((TransferDirection == EfiUsbNoData) &&
      ((Data != NULL) || (*DataLength != 0))) {
    return EFI_INVALID_PARAMETER;
  }

  if ((TransferDirection != EfiUsbNoData) &&
     ((Data == NULL) || (*DataLength == 0))) {
    return EFI_INVALID_PARAMETER;
  }

  if ((MaximumPacketLength != 8)  && (MaximumPacketLength != 16) &&
      (MaximumPacketLength != 32) && (MaximumPacketLength != 64)) {
    return EFI_INVALID_PARAMETER;
  }

  if ((DeviceSpeed == EFI_USB_SPEED_LOW) && (MaximumPacketLength != 8)) {
    return EFI_INVALID_PARAMETER;
  }

  OldTpl          = gBS->RaiseTPL (EHC_TPL);
  Ehc             = EHC_FROM_THIS (This);

  Status          = EFI_DEVICE_ERROR;
  *TransferResult = EFI_USB_ERR_SYSTEM;

  if (EhcIsHalt (Ehc) || EhcIsSysError (Ehc)) {
    EHC_ERROR (("EhcControlTransfer: HC halted at entrance\n"));

    EhcAckAllInterrupt (Ehc);
    goto ON_EXIT;
  }

  EhcAckAllInterrupt (Ehc);

  //
  // Create a new URB, insert it into the asynchronous
  // schedule list, then poll the execution status.
  //
  //
  // Encode the direction in address, although default control
  // endpoint is bidirectional. EhcCreateUrb expects this
  // combination of Ep addr and its direction.
  //
  Endpoint = (UINT8) (0 | ((TransferDirection == EfiUsbDataIn) ? 0x80 : 0));
  Urb = EhcCreateUrb (
          Ehc,
          DeviceAddress,
          Endpoint,
          DeviceSpeed,
          0,
          MaximumPacketLength,
          Translator,
          EHC_CTRL_TRANSFER,
          Request,
          Data,
          *DataLength,
          NULL,
          NULL,
          1
          );

  if (Urb == NULL) {
    EHC_ERROR (("EhcControlTransfer: failed to create URB"));

    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }

  EhcLinkQhToAsync (Ehc, Urb->Qh);
  Status = EhcExecTransfer (Ehc, Urb, TimeOut);
  EhcUnlinkQhFromAsync (Ehc, Urb->Qh);

  //
  // Get the status from URB. The result is updated in EhcCheckUrbResult
  // which is called by EhcExecTransfer
  //
  *TransferResult = Urb->Result;
  *DataLength     = Urb->Completed;

  if (*TransferResult == EFI_USB_NOERROR) {
    Status = EFI_SUCCESS;
  }

  EhcAckAllInterrupt (Ehc);
  EhcFreeUrb (Ehc, Urb);

ON_EXIT:
  Ehc->PciIo->Flush (Ehc->PciIo);
  gBS->RestoreTPL (OldTpl);

  if (EFI_ERROR (Status)) {
    EHC_ERROR (("EhcControlTransfer: error - %r, transfer - %x\n", Status, *TransferResult));
  }

  return Status;
}


/**
  Submits bulk transfer to a bulk endpoint of a USB device.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  DeviceAddress        Target device address
  @param  EndPointAddress      Endpoint number and its direction in bit 7. .
  @param  DeviceSpeed          Device speed, Low speed device doesn't support  bulk
                               transfer.
  @param  MaximumPacketLength  Maximum packet size the endpoint is capable of
                               sending or receiving.
  @param  DataBuffersNumber    Number of data buffers prepared for the transfer.
  @param  Data                 Array of pointers to the buffers of data to transmit
                                from or receive into.
  @param  DataLength           The lenght of the data buffer
  @param  DataToggle           On input, the initial data toggle for the transfer;
                               On output, it is updated to to next data toggle to
                               use                        of the subsequent bulk
                               transfer.
  @param  Translator           A pointr to the transaction translator data.
  @param  TimeOut              Indicates the maximum time, in millisecond, which
                               the transfer is allowed to complete.
  @param  TransferResult       A pointer to the detailed result information of the
                               bulk transfer.

  @return EFI_SUCCESS           : The transfer was completed successfully.
  @return EFI_OUT_OF_RESOURCES  : The transfer failed due to lack of resource.
  @return EFI_INVALID_PARAMETER : Some parameters are invalid.
  @return EFI_TIMEOUT           : The transfer failed due to timeout.
  @return EFI_DEVICE_ERROR      : The transfer failed due to host controller error.

**/
STATIC
EFI_STATUS
EFIAPI
EhcBulkTransfer (
  IN  EFI_USB2_HC_PROTOCOL                *This,
  IN  UINT8                               DeviceAddress,
  IN  UINT8                               EndPointAddress,
  IN  UINT8                               DeviceSpeed,
  IN  UINTN                               MaximumPacketLength,
  IN  UINT8                               DataBuffersNumber,
  IN  OUT VOID                            *Data[EFI_USB_MAX_BULK_BUFFER_NUM],
  IN  OUT UINTN                           *DataLength,
  IN  OUT UINT8                           *DataToggle,
  IN  UINTN                               TimeOut,
  IN  EFI_USB2_HC_TRANSACTION_TRANSLATOR  *Translator,
  OUT UINT32                              *TransferResult
  )
{
  USB2_HC_DEV             *Ehc;
  URB                     *Urb;
  EFI_TPL                 OldTpl;
  EFI_STATUS              Status;

  //
  // Validate the parameters
  //
  if ((DataLength == NULL) || (*DataLength == 0) ||
      (Data == NULL) || (Data[0] == NULL) || (TransferResult == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  if ((*DataToggle != 0) && (*DataToggle != 1)) {
    return EFI_INVALID_PARAMETER;
  }

  if ((DeviceSpeed == EFI_USB_SPEED_LOW) ||
      ((DeviceSpeed == EFI_USB_SPEED_FULL) && (MaximumPacketLength > 64)) ||
      ((EFI_USB_SPEED_HIGH == DeviceSpeed) && (MaximumPacketLength > 512))) {
    return EFI_INVALID_PARAMETER;
  }

  OldTpl          = gBS->RaiseTPL (EHC_TPL);
  Ehc             = EHC_FROM_THIS (This);

  *TransferResult = EFI_USB_ERR_SYSTEM;
  Status          = EFI_DEVICE_ERROR;

  if (EhcIsHalt (Ehc) || EhcIsSysError (Ehc)) {
    EHC_ERROR (("EhcBulkTransfer: HC is halted\n"));

    EhcAckAllInterrupt (Ehc);
    goto ON_EXIT;
  }

  EhcAckAllInterrupt (Ehc);

  //
  // Create a new URB, insert it into the asynchronous
  // schedule list, then poll the execution status.
  //
  Urb = EhcCreateUrb (
          Ehc,
          DeviceAddress,
          EndPointAddress,
          DeviceSpeed,
          *DataToggle,
          MaximumPacketLength,
          Translator,
          EHC_BULK_TRANSFER,
          NULL,
          Data[0],
          *DataLength,
          NULL,
          NULL,
          1
          );

  if (Urb == NULL) {
    EHC_ERROR (("EhcBulkTransfer: failed to create URB\n"));

    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }

  EhcLinkQhToAsync (Ehc, Urb->Qh);
  Status = EhcExecTransfer (Ehc, Urb, TimeOut);
  EhcUnlinkQhFromAsync (Ehc, Urb->Qh);

  *TransferResult = Urb->Result;
  *DataLength     = Urb->Completed;
  *DataToggle     = Urb->DataToggle;

  if (*TransferResult == EFI_USB_NOERROR) {
    Status = EFI_SUCCESS;
  }

  EhcAckAllInterrupt (Ehc);
  EhcFreeUrb (Ehc, Urb);

ON_EXIT:
  Ehc->PciIo->Flush (Ehc->PciIo);
  gBS->RestoreTPL (OldTpl);

  if (EFI_ERROR (Status)) {
    EHC_ERROR (("EhcBulkTransfer: error - %r, transfer - %x\n", Status, *TransferResult));
  }

  return Status;
}


/**
  Submits an asynchronous interrupt transfer to an
  interrupt endpoint of a USB device.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  DeviceAddress        Target device address
  @param  EndPointAddress      Endpoint number and its direction encoded in bit 7
  @param  DeviceSpeed          Indicates device speed.
  @param  MaximumPacketLength  Maximum packet size the target endpoint is capable
  @param  IsNewTransfer        If TRUE, to submit an new asynchronous interrupt
                               transfer If FALSE, to remove the specified
                               asynchronous interrupt
  @param  DataToggle           On input, the initial data toggle to use; on output,
                               it is updated to indicate the next data toggle
  @param  PollingInterval      The he interval, in milliseconds, that the transfer
                               is polled.
  @param  DataLength           The length of data to receive at the rate specified
                               by  PollingInterval.
  @param  Translator           Transaction translator to use.
  @param  CallBackFunction     Function to call at the rate specified by
                               PollingInterval
  @param  Context              Context to CallBackFunction.

  @return EFI_SUCCESS           : The request has been successfully submitted or canceled.
  @return EFI_INVALID_PARAMETER : Some parameters are invalid.
  @return EFI_OUT_OF_RESOURCES  : The request failed due to a lack of resources.
  @return EFI_DEVICE_ERROR      : The transfer failed due to host controller error.

**/
STATIC
EFI_STATUS
EFIAPI
EhcAsyncInterruptTransfer (
  IN  EFI_USB2_HC_PROTOCOL                  * This,
  IN  UINT8                                 DeviceAddress,
  IN  UINT8                                 EndPointAddress,
  IN  UINT8                                 DeviceSpeed,
  IN  UINTN                                 MaximumPacketLength,
  IN  BOOLEAN                               IsNewTransfer,
  IN  OUT UINT8                             *DataToggle,
  IN  UINTN                                 PollingInterval,
  IN  UINTN                                 DataLength,
  IN  EFI_USB2_HC_TRANSACTION_TRANSLATOR    * Translator,
  IN  EFI_ASYNC_USB_TRANSFER_CALLBACK       CallBackFunction,
  IN  VOID                                  *Context OPTIONAL
  )
{
  USB2_HC_DEV             *Ehc;
  URB                     *Urb;
  EFI_TPL                 OldTpl;
  EFI_STATUS              Status;
  UINT8                   *Data;

  //
  // Validate parameters
  //
  if (!EHCI_IS_DATAIN (EndPointAddress)) {
    return EFI_INVALID_PARAMETER;
  }

  if (IsNewTransfer) {
    if (DataLength == 0) {
      return EFI_INVALID_PARAMETER;
    }

    if ((*DataToggle != 1) && (*DataToggle != 0)) {
      return EFI_INVALID_PARAMETER;
    }

    if ((PollingInterval > 255) || (PollingInterval < 1)) {
      return EFI_INVALID_PARAMETER;
    }
  }

  OldTpl  = gBS->RaiseTPL (EHC_TPL);
  Ehc     = EHC_FROM_THIS (This);

  //
  // Delete Async interrupt transfer request. DataToggle will return
  // the next data toggle to use.
  //
  if (!IsNewTransfer) {
    Status = EhciDelAsyncIntTransfer (Ehc, DeviceAddress, EndPointAddress, DataToggle);

    EHC_DEBUG (("EhcAsyncInterruptTransfer: remove old transfer - %r\n", Status));
    goto ON_EXIT;
  }

  Status = EFI_SUCCESS;

  if (EhcIsHalt (Ehc) || EhcIsSysError (Ehc)) {
    EHC_ERROR (("EhcAsyncInterruptTransfer: HC is halt\n"));
    EhcAckAllInterrupt (Ehc);

    Status = EFI_DEVICE_ERROR;
    goto ON_EXIT;
  }

  EhcAckAllInterrupt (Ehc);

  Data = AllocatePool (DataLength);

  if (Data == NULL) {
    EHC_ERROR (("EhcAsyncInterruptTransfer: failed to allocate buffer\n"));

    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }

  Urb = EhcCreateUrb (
          Ehc,
          DeviceAddress,
          EndPointAddress,
          DeviceSpeed,
          *DataToggle,
          MaximumPacketLength,
          Translator,
          EHC_INT_TRANSFER_ASYNC,
          NULL,
          Data,
          DataLength,
          CallBackFunction,
          Context,
          PollingInterval
          );

  if (Urb == NULL) {
    EHC_ERROR (("EhcAsyncInterruptTransfer: failed to create URB\n"));

    gBS->FreePool (Data);
    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }

  //
  // New asynchronous transfer must inserted to the head.
  // Check the comments in EhcMoniteAsyncRequests
  //
  EhcLinkQhToPeriod (Ehc, Urb->Qh);
  InsertHeadList (&Ehc->AsyncIntTransfers, &Urb->UrbList);

ON_EXIT:
  Ehc->PciIo->Flush (Ehc->PciIo);
  gBS->RestoreTPL (OldTpl);

  return Status;
}


/**
  Submits synchronous interrupt transfer to an interrupt endpoint
  of a USB device.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  DeviceAddress        Target device address
  @param  EndPointAddress      Endpoint number and its direction encoded in bit 7
  @param  DeviceSpeed          Indicates device speed.
  @param  MaximumPacketLength  Maximum packet size the target endpoint is capable
                               of sending or receiving.
  @param  Data                 Buffer of data that will be transmitted to  USB
                               device or received from USB device.
  @param  DataLength           On input, the size, in bytes, of the data buffer; On
                               output, the number of bytes transferred.
  @param  DataToggle           On input, the initial data toggle to use; on output,
                               it is updated to indicate the next data toggle
  @param  TimeOut              Maximum time, in second, to complete
  @param  Translator           Transaction translator to use.
  @param  TransferResult       Variable to receive the transfer result

  @return EFI_SUCCESS           : The transfer was completed successfully.
  @return EFI_OUT_OF_RESOURCES  : The transfer failed due to lack of resource.
  @return EFI_INVALID_PARAMETER : Some parameters are invalid.
  @return EFI_TIMEOUT           : The transfer failed due to timeout.
  @return EFI_DEVICE_ERROR      : The failed due to host controller or device error

**/
STATIC
EFI_STATUS
EFIAPI
EhcSyncInterruptTransfer (
  IN  EFI_USB2_HC_PROTOCOL                *This,
  IN  UINT8                               DeviceAddress,
  IN  UINT8                               EndPointAddress,
  IN  UINT8                               DeviceSpeed,
  IN  UINTN                               MaximumPacketLength,
  IN  OUT VOID                            *Data,
  IN  OUT UINTN                           *DataLength,
  IN  OUT UINT8                           *DataToggle,
  IN  UINTN                               TimeOut,
  IN  EFI_USB2_HC_TRANSACTION_TRANSLATOR  *Translator,
  OUT UINT32                              *TransferResult
  )
{
  USB2_HC_DEV             *Ehc;
  EFI_TPL                 OldTpl;
  URB                     *Urb;
  EFI_STATUS              Status;

  //
  // Validates parameters
  //
  if ((DataLength == NULL) || (*DataLength == 0) ||
      (Data == NULL) || (TransferResult == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  if (!EHCI_IS_DATAIN (EndPointAddress)) {
    return EFI_INVALID_PARAMETER;
  }

  if ((*DataToggle != 1) && (*DataToggle != 0)) {
    return EFI_INVALID_PARAMETER;
  }

  if (((DeviceSpeed == EFI_USB_SPEED_LOW) && (MaximumPacketLength != 8))  ||
      ((DeviceSpeed == EFI_USB_SPEED_FULL) && (MaximumPacketLength > 64)) ||
      ((DeviceSpeed == EFI_USB_SPEED_HIGH) && (MaximumPacketLength > 3072))) {
    return EFI_INVALID_PARAMETER;
  }

  OldTpl          = gBS->RaiseTPL (EHC_TPL);
  Ehc             = EHC_FROM_THIS (This);

  *TransferResult = EFI_USB_ERR_SYSTEM;
  Status          = EFI_DEVICE_ERROR;

  if (EhcIsHalt (Ehc) || EhcIsSysError (Ehc)) {
    EHC_ERROR (("EhcSyncInterruptTransfer: HC is halt\n"));

    EhcAckAllInterrupt (Ehc);
    goto ON_EXIT;
  }

  EhcAckAllInterrupt (Ehc);

  Urb = EhcCreateUrb (
          Ehc,
          DeviceAddress,
          EndPointAddress,
          DeviceSpeed,
          *DataToggle,
          MaximumPacketLength,
          Translator,
          EHC_INT_TRANSFER_SYNC,
          NULL,
          Data,
          *DataLength,
          NULL,
          NULL,
          1
          );

  if (Urb == NULL) {
    EHC_ERROR (("EhcSyncInterruptTransfer: failed to create URB\n"));

    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }

  EhcLinkQhToPeriod (Ehc, Urb->Qh);
  Status = EhcExecTransfer (Ehc, Urb, TimeOut);
  EhcUnlinkQhFromPeriod (Ehc, Urb->Qh);

  *TransferResult = Urb->Result;
  *DataLength     = Urb->Completed;
  *DataToggle     = Urb->DataToggle;

  if (*TransferResult == EFI_USB_NOERROR) {
    Status = EFI_SUCCESS;
  }

ON_EXIT:
  Ehc->PciIo->Flush (Ehc->PciIo);
  gBS->RestoreTPL (OldTpl);

  if (EFI_ERROR (Status)) {
    EHC_ERROR (("EhcSyncInterruptTransfer: error - %r, transfer - %x\n", Status, *TransferResult));
  }

  return Status;
}


/**
  Submits isochronous transfer to a target USB device.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  DeviceAddress        Target device address
  @param  EndPointAddress      End point address with its direction
  @param  DeviceSpeed          Device speed, Low speed device doesn't support this
                               type.
  @param  MaximumPacketLength  Maximum packet size that the endpoint is capable of
                               sending or receiving.
  @param  DataBuffersNumber    Number of data buffers prepared for the transfer.
  @param  Data                 Array of pointers to the buffers of data that will
                               be transmitted to USB device or received from USB
                               device.
  @param  DataLength           The size, in bytes, of the data buffer
  @param  Translator           Transaction translator to use.
  @param  TransferResult       Variable to receive the transfer result

  @return EFI_UNSUPPORTED : Isochronous transfer is unsupported.

**/
STATIC
EFI_STATUS
EFIAPI
EhcIsochronousTransfer (
  IN  EFI_USB2_HC_PROTOCOL                *This,
  IN  UINT8                               DeviceAddress,
  IN  UINT8                               EndPointAddress,
  IN  UINT8                               DeviceSpeed,
  IN  UINTN                               MaximumPacketLength,
  IN  UINT8                               DataBuffersNumber,
  IN  OUT VOID                            *Data[EFI_USB_MAX_ISO_BUFFER_NUM],
  IN  UINTN                               DataLength,
  IN  EFI_USB2_HC_TRANSACTION_TRANSLATOR  *Translator,
  OUT UINT32                              *TransferResult
  )
{
  return EFI_UNSUPPORTED;
}


/**
  Submits Async isochronous transfer to a target USB device.

  @param  This                 This EFI_USB2_HC_PROTOCOL instance.
  @param  DeviceAddress        Target device address
  @param  EndPointAddress      End point address with its direction
  @param  DeviceSpeed          Device speed, Low speed device doesn't support this
                               type.
  @param  MaximumPacketLength  Maximum packet size that the endpoint is capable of
                               sending or receiving.
  @param  DataBuffersNumber    Number of data buffers prepared for the transfer.
  @param  Data                 Array of pointers to the buffers of data that will
                               be transmitted to USB device or received from USB
                               device.
  @param  DataLength           The size, in bytes, of the data buffer
  @param  Translator           Transaction translator to use.
  @param  IsochronousCallBack  Function to be called when the transfer complete
  @param  Context              Context passed to the call back function as
                               parameter

  @return EFI_UNSUPPORTED : Isochronous transfer isn't supported

**/
STATIC
EFI_STATUS
EFIAPI
EhcAsyncIsochronousTransfer (
  IN  EFI_USB2_HC_PROTOCOL                *This,
  IN  UINT8                               DeviceAddress,
  IN  UINT8                               EndPointAddress,
  IN  UINT8                               DeviceSpeed,
  IN  UINTN                               MaximumPacketLength,
  IN  UINT8                               DataBuffersNumber,
  IN  OUT VOID                            *Data[EFI_USB_MAX_ISO_BUFFER_NUM],
  IN  UINTN                               DataLength,
  IN  EFI_USB2_HC_TRANSACTION_TRANSLATOR  *Translator,
  IN  EFI_ASYNC_USB_TRANSFER_CALLBACK     IsochronousCallBack,
  IN  VOID                                *Context
  )
{
  return EFI_UNSUPPORTED;
}

EFI_STATUS
EFIAPI
EhcDriverEntryPoint (
  IN EFI_HANDLE           ImageHandle,
  IN EFI_SYSTEM_TABLE     *SystemTable
  )
/*++

Routine Description:

  Entry point for EFI drivers.

Arguments:

  ImageHandle - EFI_HANDLE
  SystemTable - EFI_SYSTEM_TABLE

Returns:

  EFI_SUCCESS         Success
  EFI_DEVICE_ERROR    Fail

--*/
{
  return EfiLibInstallDriverBindingComponentName2 (
           ImageHandle,
           SystemTable,
           &gEhciDriverBinding,
           ImageHandle,
           &gEhciComponentName,
           &gEhciComponentName2
           );
}


/**
  Test to see if this driver supports ControllerHandle. Any
  ControllerHandle that has Usb2HcProtocol installed will
  be supported.

  @param  This                 Protocol instance pointer.
  @param  Controlle            Handle of device to test
  @param  RemainingDevicePath  Not used

  @return EFI_SUCCESS         : This driver supports this device.
  @return EFI_UNSUPPORTED     : This driver does not support this device.

**/
EFI_STATUS
EFIAPI
EhcDriverBindingSupported (
  IN EFI_DRIVER_BINDING_PROTOCOL *This,
  IN EFI_HANDLE                  Controller,
  IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
  )
{
  EFI_STATUS              Status;
  EFI_PCI_IO_PROTOCOL     *PciIo;
  USB_CLASSC              UsbClassCReg;

  //
  // Test whether there is PCI IO Protocol attached on the controller handle.
  //
  Status = gBS->OpenProtocol (
                  Controller,
                  &gEfiPciIoProtocolGuid,
                  (VOID **) &PciIo,
                  This->DriverBindingHandle,
                  Controller,
                  EFI_OPEN_PROTOCOL_BY_DRIVER
                  );

  if (EFI_ERROR (Status)) {
    return EFI_UNSUPPORTED;
  }

  Status = PciIo->Pci.Read (
                        PciIo,
                        EfiPciIoWidthUint8,
                        EHC_PCI_CLASSC,
                        sizeof (USB_CLASSC) / sizeof (UINT8),
                        &UsbClassCReg
                        );

  if (EFI_ERROR (Status)) {
    Status = EFI_UNSUPPORTED;
    goto ON_EXIT;
  }

  //
  // Test whether the controller belongs to Ehci type
  //
  if ((UsbClassCReg.BaseCode     != PCI_CLASS_SERIAL) ||
      (UsbClassCReg.SubClassCode != PCI_CLASS_SERIAL_USB) ||
      (UsbClassCReg.PI           != EHC_PCI_CLASSC_PI)) {

    Status = EFI_UNSUPPORTED;
  }

ON_EXIT:
  gBS->CloseProtocol (
         Controller,
         &gEfiPciIoProtocolGuid,
         This->DriverBindingHandle,
         Controller
         );

  return Status;
}


/**
  Create and initialize a USB2_HC_DEV

  @param  PciIo                The PciIo on this device

  @return The allocated and initialized USB2_HC_DEV structure
  @return if created, otherwise NULL.

**/
STATIC
USB2_HC_DEV *
EhcCreateUsb2Hc (
  IN EFI_PCI_IO_PROTOCOL  *PciIo
  )
{
  USB2_HC_DEV             *Ehc;
  EFI_STATUS              Status;

  Ehc = AllocateZeroPool (sizeof (USB2_HC_DEV));

  if (Ehc == NULL) {
    return NULL;
  }

  //
  // Init EFI_USB2_HC_PROTOCOL interface and private data structure
  //
  Ehc->Signature                        = USB2_HC_DEV_SIGNATURE;

  Ehc->Usb2Hc.GetCapability             = EhcGetCapability;
  Ehc->Usb2Hc.Reset                     = EhcReset;
  Ehc->Usb2Hc.GetState                  = EhcGetState;
  Ehc->Usb2Hc.SetState                  = EhcSetState;
  Ehc->Usb2Hc.ControlTransfer           = EhcControlTransfer;
  Ehc->Usb2Hc.BulkTransfer              = EhcBulkTransfer;
  Ehc->Usb2Hc.AsyncInterruptTransfer    = EhcAsyncInterruptTransfer;
  Ehc->Usb2Hc.SyncInterruptTransfer     = EhcSyncInterruptTransfer;
  Ehc->Usb2Hc.IsochronousTransfer       = EhcIsochronousTransfer;
  Ehc->Usb2Hc.AsyncIsochronousTransfer  = EhcAsyncIsochronousTransfer;
  Ehc->Usb2Hc.GetRootHubPortStatus      = EhcGetRootHubPortStatus;
  Ehc->Usb2Hc.SetRootHubPortFeature     = EhcSetRootHubPortFeature;
  Ehc->Usb2Hc.ClearRootHubPortFeature   = EhcClearRootHubPortFeature;
  Ehc->Usb2Hc.MajorRevision             = 0x1;
  Ehc->Usb2Hc.MinorRevision             = 0x1;

  Ehc->PciIo = PciIo;

  InitializeListHead (&Ehc->AsyncIntTransfers);

  Ehc->HcStructParams = EhcReadCapRegister (Ehc, EHC_HCSPARAMS_OFFSET);
  Ehc->HcCapParams    = EhcReadCapRegister (Ehc, EHC_HCCPARAMS_OFFSET);
  Ehc->CapLen         = EhcReadCapRegister (Ehc, EHC_CAPLENGTH_OFFSET) & 0x0FF;

  EHC_DEBUG (("EhcCreateUsb2Hc: capability length %d\n", Ehc->CapLen));

  //
  // Create AsyncRequest Polling Timer
  //
  Status = gBS->CreateEvent (
                  EVT_TIMER | EVT_NOTIFY_SIGNAL,
                  TPL_CALLBACK,
                  EhcMoniteAsyncRequests,
                  Ehc,
                  &Ehc->PollTimer
                  );

  if (EFI_ERROR (Status)) {
    gBS->FreePool (Ehc);
    return NULL;
  }

  return Ehc;
}


/**
  Starting the Usb EHCI Driver

  @param  This                 Protocol instance pointer.
  @param  Controller           Handle of device to test
  @param  RemainingDevicePath  Not used

  @return EFI_SUCCESS          : supports this device.
  @return EFI_UNSUPPORTED      : do not support this device.
  @return EFI_DEVICE_ERROR     : cannot be started due to device Error
  @return EFI_OUT_OF_RESOURCES : cannot allocate resources

**/
EFI_STATUS
EFIAPI
EhcDriverBindingStart (
  IN EFI_DRIVER_BINDING_PROTOCOL *This,
  IN EFI_HANDLE                  Controller,
  IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
  )
{
  EFI_STATUS              Status;
  USB2_HC_DEV             *Ehc;
  EFI_PCI_IO_PROTOCOL     *PciIo;

  //
  // Open the PciIo Protocol, then enable the USB host controller
  //
  Status = gBS->OpenProtocol (
                  Controller,
                  &gEfiPciIoProtocolGuid,
                  (VOID **) &PciIo,
                  This->DriverBindingHandle,
                  Controller,
                  EFI_OPEN_PROTOCOL_BY_DRIVER
                  );

  if (EFI_ERROR (Status)) {
    EHC_ERROR (("EhcDriverBindingStart: failed to open PCI_IO\n"));
    return EFI_DEVICE_ERROR;
  }

  Status = PciIo->Attributes (
                    PciIo,
                    EfiPciIoAttributeOperationEnable,
                    EFI_PCI_DEVICE_ENABLE,
                    NULL
                    );

  if (EFI_ERROR (Status)) {
    EHC_ERROR (("EhcDriverBindingStart: failed to enable controller\n"));
    goto CLOSE_PCIIO;
  }

  //
  // Create then install USB2_HC_PROTOCOL
  //
  Ehc = EhcCreateUsb2Hc (PciIo);

  if (Ehc == NULL) {
    EHC_ERROR (("EhcDriverBindingStart: failed to create USB2_HC\n"));

    Status = EFI_OUT_OF_RESOURCES;
    goto CLOSE_PCIIO;
  }

  Status = gBS->InstallProtocolInterface (
                  &Controller,
                  &gEfiUsb2HcProtocolGuid,
                  EFI_NATIVE_INTERFACE,
                  &Ehc->Usb2Hc
                  );

  if (EFI_ERROR (Status)) {
    EHC_ERROR (("EhcDriverBindingStart: failed to install USB2_HC Protocol\n"));
    goto FREE_POOL;
  }

  //
  // Robustnesss improvement such as for UoL
  //
  EhcClearLegacySupport (Ehc);
  EhcResetHC (Ehc, EHC_RESET_TIMEOUT);

  Status = EhcInitHC (Ehc);

  if (EFI_ERROR (Status)) {
    EHC_ERROR (("EhcDriverBindingStart: failed to init host controller\n"));
    goto UNINSTALL_USBHC;
  }

  //
  // Start the asynchronous interrupt monitor
  //
  Status = gBS->SetTimer (Ehc->PollTimer, TimerPeriodic, EHC_ASYNC_POLL_INTERVAL);

  if (EFI_ERROR (Status)) {
    EHC_ERROR (("EhcDriverBindingStart: failed to start async interrupt monitor\n"));

    EhcHaltHC (Ehc, EHC_GENERIC_TIMEOUT);
    goto UNINSTALL_USBHC;
  }

  //
  // Install the component name protocol, don't fail the start
  // because of something for display.
  //
  AddUnicodeString2 (
    "eng",
    gEhciComponentName.SupportedLanguages,
    &Ehc->ControllerNameTable,
    L"Enhanced Host Controller (USB 2.0)",
    TRUE
    );
  AddUnicodeString2 (
    "en",
    gEhciComponentName2.SupportedLanguages,
    &Ehc->ControllerNameTable,
    L"Enhanced Host Controller (USB 2.0)",
    FALSE
    );


  EHC_DEBUG (("EhcDriverBindingStart: EHCI started for controller @ %x\n", Controller));
  return EFI_SUCCESS;

UNINSTALL_USBHC:
  gBS->UninstallProtocolInterface (
         Controller,
         &gEfiUsb2HcProtocolGuid,
         &Ehc->Usb2Hc
         );

FREE_POOL:
  EhcFreeSched (Ehc);
  gBS->CloseEvent (Ehc->PollTimer);
  gBS->FreePool (Ehc);

CLOSE_PCIIO:
  gBS->CloseProtocol (
         Controller,
         &gEfiPciIoProtocolGuid,
         This->DriverBindingHandle,
         Controller
         );

  return Status;
}


/**
  Stop this driver on ControllerHandle. Support stoping any child handles
  created by this driver.

  @param  This                 Protocol instance pointer.
  @param  Controller           Handle of device to stop driver on
  @param  NumberOfChildren     Number of Children in the ChildHandleBuffer
  @param  ChildHandleBuffer    List of handles for the children we need to stop.

  @return EFI_SUCCESS         Success
  @return EFI_DEVICE_ERROR    Fail

**/
EFI_STATUS
EFIAPI
EhcDriverBindingStop (
  IN EFI_DRIVER_BINDING_PROTOCOL *This,
  IN EFI_HANDLE                  Controller,
  IN UINTN                       NumberOfChildren,
  IN EFI_HANDLE                  *ChildHandleBuffer
  )
{
  EFI_STATUS            Status;
  EFI_USB2_HC_PROTOCOL  *Usb2Hc;
  EFI_PCI_IO_PROTOCOL   *PciIo;
  USB2_HC_DEV           *Ehc;

  //
  // Test whether the Controller handler passed in is a valid
  // Usb controller handle that should be supported, if not,
  // return the error status directly
  //
  Status = gBS->OpenProtocol (
                  Controller,
                  &gEfiUsb2HcProtocolGuid,
                  (VOID **) &Usb2Hc,
                  This->DriverBindingHandle,
                  Controller,
                  EFI_OPEN_PROTOCOL_GET_PROTOCOL
                  );

  if (EFI_ERROR (Status)) {
    return Status;
  }

  Ehc   = EHC_FROM_THIS (Usb2Hc);
  PciIo = Ehc->PciIo;

  //
  // Stop AsyncRequest Polling timer then stop the EHCI driver
  // and uninstall the EHCI protocl.
  //
  gBS->SetTimer (Ehc->PollTimer, TimerCancel, EHC_ASYNC_POLL_INTERVAL);
  EhcHaltHC (Ehc, EHC_GENERIC_TIMEOUT);

  Status = gBS->UninstallProtocolInterface (
                  Controller,
                  &gEfiUsb2HcProtocolGuid,
                  Usb2Hc
                  );

  if (EFI_ERROR (Status)) {
    return Status;
  }

  if (Ehc->PollTimer != NULL) {
    gBS->CloseEvent (Ehc->PollTimer);
  }

  EhcFreeSched (Ehc);

  if (Ehc->ControllerNameTable) {
    FreeUnicodeStringTable (Ehc->ControllerNameTable);
  }

  //
  // Disable the USB Host Controller
  //
  PciIo->Attributes (
           PciIo,
           EfiPciIoAttributeOperationDisable,
           EFI_PCI_DEVICE_ENABLE,
           NULL
           );

  gBS->CloseProtocol (
         Controller,
         &gEfiPciIoProtocolGuid,
         This->DriverBindingHandle,
         Controller
         );

  gBS->FreePool (Ehc);
  return Status;
}

EFI_DRIVER_BINDING_PROTOCOL
gEhciDriverBinding = {
  EhcDriverBindingSupported,
  EhcDriverBindingStart,
  EhcDriverBindingStop,
  0x10,
  NULL,
  NULL
};