audk/IntelFrameworkModulePkg/Bus/Isa/Ps2MouseDxe/CommPs2.c

/*++

Copyright (c) 2006 - 2007, Intel Corporation. All rights reserved. <BR> 
This software and associated documentation (if any) is furnished
under a license and may only be used or copied in accordance
with the terms of the license. Except as permitted by such
license, no part of this software or documentation may be
reproduced, stored in a retrieval system, or transmitted in any
form or by any means without the express written consent of
Intel Corporation.


Module Name:

  CommPs2.c
    
Abstract:   

  PS2 Mouse Communication Interface 


Revision History

--*/

//
// Include common header file for this module.
//
#include "CommonHeader.h"

#include "Ps2Mouse.h"
#include "CommPs2.h"

UINT8 SampleRateTbl[MAX_SR]   = { 0xa, 0x14, 0x28, 0x3c, 0x50, 0x64, 0xc8 };

UINT8 ResolutionTbl[MAX_CMR]  = { 0, 1, 2, 3 };

EFI_STATUS
KbcSelfTest (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description

Returns:

  EFI_DEVICE_ERROR - GC_TODO: Add description for return value
  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  EFI_STATUS  Status;
  UINT8       Data;

  //
  // Keyboard controller self test
  //
  Status = Out8042Command (IsaIo, SELF_TEST);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Read return code
  //
  Status = In8042Data (IsaIo, &Data);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  if (Data != 0x55) {
    return EFI_DEVICE_ERROR;
  }
  //
  // Set system flag
  //
  Status = Out8042Command (IsaIo, READ_CMD_BYTE);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Status = In8042Data (IsaIo, &Data);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Status = Out8042Command (IsaIo, WRITE_CMD_BYTE);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Data |= CMD_SYS_FLAG;
  Status = Out8042Data (IsaIo, Data);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  return EFI_SUCCESS;
}

EFI_STATUS
KbcEnableAux (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  //
  // Send 8042 enable mouse command
  //
  return Out8042Command (IsaIo, ENABLE_AUX);
}

EFI_STATUS
KbcDisableAux (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  //
  // Send 8042 disable mouse command
  //
  return Out8042Command (IsaIo, DISABLE_AUX);
}

EFI_STATUS
KbcEnableKb (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  //
  // Send 8042 enable keyboard command
  //
  return Out8042Command (IsaIo, ENABLE_KB);
}

EFI_STATUS
KbcDisableKb (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  //
  // Send 8042 disable keyboard command
  //
  return Out8042Command (IsaIo, DISABLE_KB);
}

EFI_STATUS
CheckKbStatus (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  OUT BOOLEAN                             *KeyboardEnable
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo           - GC_TODO: add argument description
  KeyboardEnable  - GC_TODO: add argument description

Returns:

  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  EFI_STATUS  Status;
  UINT8       Data;

  //
  // Send command to read KBC command byte
  //
  Status = Out8042Command (IsaIo, READ_CMD_BYTE);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Status = In8042Data (IsaIo, &Data);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Check keyboard enable or not
  //
  if ((Data & CMD_KB_STS) == CMD_KB_DIS) {
    *KeyboardEnable = FALSE;
  } else {
    *KeyboardEnable = TRUE;
  }

  return EFI_SUCCESS;
}

EFI_STATUS
PS2MouseReset (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description

Returns:

  EFI_DEVICE_ERROR - GC_TODO: Add description for return value
  EFI_DEVICE_ERROR - GC_TODO: Add description for return value
  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  EFI_STATUS  Status;
  UINT8       Data;

  Status = Out8042AuxCommand (IsaIo, RESET_CMD, FALSE);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Status = In8042AuxData (IsaIo, &Data);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Check BAT Complete Code
  //
  if (Data != PS2MOUSE_BAT1) {
    return EFI_DEVICE_ERROR;
  }

  Status = In8042AuxData (IsaIo, &Data);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Check BAT Complete Code
  //
  if (Data != PS2MOUSE_BAT2) {
    return EFI_DEVICE_ERROR;
  }

  return EFI_SUCCESS;
}

EFI_STATUS
PS2MouseSetSampleRate (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN MOUSE_SR                             SampleRate
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo       - GC_TODO: add argument description
  SampleRate  - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  EFI_STATUS  Status;

  //
  // Send auxiliary command to set mouse sample rate
  //
  Status = Out8042AuxCommand (IsaIo, SETSR_CMD, FALSE);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Status = Out8042AuxData (IsaIo, SampleRateTbl[SampleRate]);

  return Status;
}

EFI_STATUS
PS2MouseSetResolution (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN MOUSE_RE                             Resolution
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo       - GC_TODO: add argument description
  Resolution  - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  EFI_STATUS  Status;

  //
  // Send auxiliary command to set mouse resolution
  //
  Status = Out8042AuxCommand (IsaIo, SETRE_CMD, FALSE);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Status = Out8042AuxData (IsaIo, ResolutionTbl[Resolution]);

  return Status;
}

EFI_STATUS
PS2MouseSetScaling (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN MOUSE_SF                             Scaling
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo   - GC_TODO: add argument description
  Scaling - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  UINT8 Command;

  Command = (UINT8) (Scaling == SF1 ? SETSF1_CMD : SETSF2_CMD);

  //
  // Send auxiliary command to set mouse scaling data
  //
  return Out8042AuxCommand (IsaIo, Command, FALSE);
}

EFI_STATUS
PS2MouseEnable (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  //
  // Send auxiliary command to enable mouse
  //
  return Out8042AuxCommand (IsaIo, ENABLE_CMD, FALSE);
}

EFI_STATUS
PS2MouseGetPacket (
  PS2_MOUSE_DEV     *MouseDev
  )
/*++

Routine Description:

  Get mouse packet . Only care first 3 bytes

Arguments:

  MouseDev  - Pointer of PS2 Mouse Private Data Structure 

Returns:

  EFI_NOT_READY -  Mouse Device not ready to input data packet, or some error happened during getting the packet
  EFI_SUCCESS - The data packet is gotten successfully.

--*/
{
  EFI_STATUS  Status;
  BOOLEAN     KeyboardEnable;
  UINT8       Packet[PS2_PACKET_LENGTH];
  UINT8       Data;
  UINTN       Count;
  UINTN       State;
  INT16       RelativeMovementX;
  INT16       RelativeMovementY;
  BOOLEAN     LButton;
  BOOLEAN     RButton;

  KeyboardEnable  = FALSE;
  Count           = 1;
  State           = PS2_READ_BYTE_ONE;

  //
  // State machine to get mouse packet
  //
  while (1) {

    switch (State) {
    case PS2_READ_BYTE_ONE:
      //
      // Read mouse first byte data, if failed, immediately return
      //
      KbcDisableAux (MouseDev->IsaIo);
      Status = PS2MouseRead (MouseDev->IsaIo, &Data, &Count, State);
      if (EFI_ERROR (Status)) {
        KbcEnableAux (MouseDev->IsaIo);
        return EFI_NOT_READY;
      }

      if (Count != 1) {
        KbcEnableAux (MouseDev->IsaIo);
        return EFI_NOT_READY;
      }

      if (IS_PS2_SYNC_BYTE (Data)) {
        Packet[0] = Data;
        State     = PS2_READ_DATA_BYTE;

        CheckKbStatus (MouseDev->IsaIo, &KeyboardEnable);
        KbcDisableKb (MouseDev->IsaIo);
        KbcEnableAux (MouseDev->IsaIo);
      }
      break;

    case PS2_READ_DATA_BYTE:
      Count   = 2;
      Status  = PS2MouseRead (MouseDev->IsaIo, (Packet + 1), &Count, State);
      if (EFI_ERROR (Status)) {
        if (KeyboardEnable) {
          KbcEnableKb (MouseDev->IsaIo);
        }

        return EFI_NOT_READY;
      }

      if (Count != 2) {
        if (KeyboardEnable) {
          KbcEnableKb (MouseDev->IsaIo);
        }

        return EFI_NOT_READY;
      }

      State = PS2_PROCESS_PACKET;
      break;

    case PS2_PROCESS_PACKET:
      if (KeyboardEnable) {
        KbcEnableKb (MouseDev->IsaIo);
      }
      //
      // Decode the packet
      //
      RelativeMovementX = Packet[1];
      RelativeMovementY = Packet[2];
      //
      //               Bit 7   |    Bit 6   |    Bit 5   |   Bit 4    |   Bit 3  |   Bit 2    |   Bit 1   |   Bit 0 
      //  Byte 0  | Y overflow | X overflow | Y sign bit | X sign bit | Always 1 | Middle Btn | Right Btn | Left Btn 
      //  Byte 1  |                                           8 bit X Movement 
      //  Byte 2  |                                           8 bit Y Movement 
      // 
      // X sign bit + 8 bit X Movement : 9-bit signed twos complement integer that presents the relative displacement of the device in the X direction since the last data transmission.
      // Y sign bit + 8 bit Y Movement : Same as X sign bit + 8 bit X Movement.
      //
      //
      // First, Clear X and Y high 8 bits
      //
      RelativeMovementX = (INT16) (RelativeMovementX & 0xFF); 
      RelativeMovementY = (INT16) (RelativeMovementY & 0xFF); 
      //
      // Second, if the 9-bit signed twos complement integer is negative, set the high 8 bit 0xff
      //
      if ((Packet[0] & 0x10) != 0) {
        RelativeMovementX = (INT16) (RelativeMovementX | 0xFF00);
      }
      if ((Packet[0] & 0x20) != 0) {
        RelativeMovementY = (INT16) (RelativeMovementY | 0xFF00);
      }

      
      RButton           = (UINT8) (Packet[0] & 0x2);
      LButton           = (UINT8) (Packet[0] & 0x1);

      //
      // Update mouse state
      //
      MouseDev->State.RelativeMovementX += RelativeMovementX;
      MouseDev->State.RelativeMovementY -= RelativeMovementY;
      MouseDev->State.RightButton = (UINT8) (RButton ? TRUE : FALSE);
      MouseDev->State.LeftButton  = (UINT8) (LButton ? TRUE : FALSE);
      MouseDev->StateChanged      = TRUE;

      return EFI_SUCCESS;
    }
  }
}

EFI_STATUS
PS2MouseRead (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  OUT VOID                                *Buffer,
  IN OUT UINTN                            *BufSize,
  IN  UINTN                               State
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo   - GC_TODO: add argument description
  Buffer  - GC_TODO: add argument description
  BufSize - GC_TODO: add argument description
  State   - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  EFI_STATUS  Status;
  UINTN       BytesRead;

  Status    = EFI_SUCCESS;
  BytesRead = 0;

  if (State == PS2_READ_BYTE_ONE) {
    //
    // Check input for mouse
    //
    Status = CheckForInput (IsaIo);

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

  while (BytesRead < *BufSize) {

    Status = WaitOutputFull (IsaIo, TIMEOUT);
    if (EFI_ERROR (Status)) {
      break;
    }

    IsaIo->Io.Read (IsaIo, EfiIsaIoWidthUint8, KBC_DATA_PORT, 1, Buffer);

    BytesRead++;
    Buffer = (UINT8 *) Buffer + 1;
  }
  //
  // Verify the correct number of bytes read
  //
  if (BytesRead == 0 || BytesRead != *BufSize) {
    Status = EFI_NOT_FOUND;
  }

  *BufSize = BytesRead;
  return Status;
}
//
// 8042 I/O function
//
EFI_STATUS
Out8042Command (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN UINT8                                Command
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo   - GC_TODO: add argument description
  Command - GC_TODO: add argument description

Returns:

  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  EFI_STATUS  Status;
  UINT8       Data;

  //
  // Wait keyboard controller input buffer empty
  //
  Status = WaitInputEmpty (IsaIo, TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Send command
  //
  Data = Command;
  IsaIo->Io.Write (IsaIo, EfiIsaIoWidthUint8, KBC_CMD_STS_PORT, 1, &Data);

  Status = WaitInputEmpty (IsaIo, TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  return EFI_SUCCESS;
}

EFI_STATUS
Out8042Data (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN UINT8                                Data
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description
  Data  - GC_TODO: add argument description

Returns:

  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  EFI_STATUS  Status;
  UINT8       temp;
  //
  // Wait keyboard controller input buffer empty
  //
  Status = WaitInputEmpty (IsaIo, TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  temp = Data;
  IsaIo->Io.Write (IsaIo, EfiIsaIoWidthUint8, KBC_DATA_PORT, 1, &temp);

  Status = WaitInputEmpty (IsaIo, TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  return EFI_SUCCESS;
}

EFI_STATUS
In8042Data (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN OUT UINT8                            *Data
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description
  Data  - GC_TODO: add argument description

Returns:

  EFI_TIMEOUT - GC_TODO: Add description for return value
  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  UINTN Delay;
  UINT8 temp;

  Delay = TIMEOUT / 50;

  do {
    IsaIo->Io.Read (IsaIo, EfiIsaIoWidthUint8, KBC_CMD_STS_PORT, 1, &temp);

    //
    // Check keyboard controller status bit 0(output buffer status)
    //
    if ((temp & KBC_OUTB) == KBC_OUTB) {
      break;
    }

    gBS->Stall (50);
    Delay--;
  } while (Delay);

  if (Delay == 0) {
    return EFI_TIMEOUT;
  }

  IsaIo->Io.Read (IsaIo, EfiIsaIoWidthUint8, KBC_DATA_PORT, 1, Data);

  return EFI_SUCCESS;
}

EFI_STATUS
Out8042AuxCommand (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN UINT8                                Command,
  IN BOOLEAN                              Resend
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo   - GC_TODO: add argument description
  Command - GC_TODO: add argument description
  Resend  - GC_TODO: add argument description

Returns:

  EFI_SUCCESS - GC_TODO: Add description for return value
  EFI_DEVICE_ERROR - GC_TODO: Add description for return value
  EFI_DEVICE_ERROR - GC_TODO: Add description for return value
  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  EFI_STATUS  Status;
  UINT8       Data;

  //
  // Wait keyboard controller input buffer empty
  //
  Status = WaitInputEmpty (IsaIo, TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Send write to auxiliary device command
  //
  Data = WRITE_AUX_DEV;
  IsaIo->Io.Write (IsaIo, EfiIsaIoWidthUint8, KBC_CMD_STS_PORT, 1, &Data);

  Status = WaitInputEmpty (IsaIo, TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Send auxiliary device command
  //
  IsaIo->Io.Write (IsaIo, EfiIsaIoWidthUint8, KBC_DATA_PORT, 1, &Command);

  //
  // Read return code
  //
  Status = In8042AuxData (IsaIo, &Data);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  if (Data == PS2_ACK) {
    //
    // Receive mouse acknowledge, command send success
    //
    return EFI_SUCCESS;

  } else if (Resend) {
    //
    // Resend fail
    //
    return EFI_DEVICE_ERROR;

  } else if (Data == PS2_RESEND) {
    //
    // Resend command
    //
    Status = Out8042AuxCommand (IsaIo, Command, TRUE);
    if (EFI_ERROR (Status)) {
      return Status;
    }

  } else {
    //
    // Invalid return code
    //
    return EFI_DEVICE_ERROR;

  }

  return EFI_SUCCESS;
}

EFI_STATUS
Out8042AuxData (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN UINT8                                Data
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description
  Data  - GC_TODO: add argument description

Returns:

  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  EFI_STATUS  Status;
  UINT8       Temp;
  //
  // Wait keyboard controller input buffer empty
  //
  Status = WaitInputEmpty (IsaIo, TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Send write to auxiliary device command
  //
  Temp = WRITE_AUX_DEV;
  IsaIo->Io.Write (IsaIo, EfiIsaIoWidthUint8, KBC_CMD_STS_PORT, 1, &Temp);

  Status = WaitInputEmpty (IsaIo, TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Temp = Data;
  IsaIo->Io.Write (IsaIo, EfiIsaIoWidthUint8, KBC_DATA_PORT, 1, &Temp);

  Status = WaitInputEmpty (IsaIo, TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  return EFI_SUCCESS;
}

EFI_STATUS
In8042AuxData (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN OUT UINT8                            *Data
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description
  Data  - GC_TODO: add argument description

Returns:

  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  EFI_STATUS  Status;

  //
  // wait for output data
  //
  Status = WaitOutputFull (IsaIo, BAT_TIMEOUT);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  IsaIo->Io.Read (IsaIo, EfiIsaIoWidthUint8, KBC_DATA_PORT, 1, Data);

  return EFI_SUCCESS;
}

EFI_STATUS
CheckForInput (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo - GC_TODO: add argument description

Returns:

  EFI_NOT_READY - GC_TODO: Add description for return value
  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  UINT8 Data;

  IsaIo->Io.Read (IsaIo, EfiIsaIoWidthUint8, KBC_CMD_STS_PORT, 1, &Data);

  //
  // Check keyboard controller status, if it is output buffer full and for auxiliary device
  //
  if ((Data & (KBC_OUTB | KBC_AUXB)) != (KBC_OUTB | KBC_AUXB)) {
    return EFI_NOT_READY;
  }

  return EFI_SUCCESS;
}

EFI_STATUS
WaitInputEmpty (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN UINTN                                Timeout
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo   - GC_TODO: add argument description
  Timeout - GC_TODO: add argument description

Returns:

  EFI_TIMEOUT - GC_TODO: Add description for return value
  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  UINTN Delay;
  UINT8 Data;

  Delay = Timeout / 50;

  do {
    IsaIo->Io.Read (IsaIo, EfiIsaIoWidthUint8, KBC_CMD_STS_PORT, 1, &Data);

    //
    // Check keyboard controller status bit 1(input buffer status)
    //
    if ((Data & KBC_INPB) == 0) {
      break;
    }

    gBS->Stall (50);
    Delay--;
  } while (Delay);

  if (Delay == 0) {
    return EFI_TIMEOUT;
  }

  return EFI_SUCCESS;
}

EFI_STATUS
WaitOutputFull (
  IN EFI_ISA_IO_PROTOCOL                  *IsaIo,
  IN UINTN                                Timeout
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  IsaIo   - GC_TODO: add argument description
  Timeout - GC_TODO: add argument description

Returns:

  EFI_TIMEOUT - GC_TODO: Add description for return value
  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  UINTN Delay;
  UINT8 Data;

  Delay = Timeout / 50;

  do {
    IsaIo->Io.Read (IsaIo, EfiIsaIoWidthUint8, KBC_CMD_STS_PORT, 1, &Data);

    //
    // Check keyboard controller status bit 0(output buffer status)
    //  & bit5(output buffer for auxiliary device)
    //
    if ((Data & (KBC_OUTB | KBC_AUXB)) == (KBC_OUTB | KBC_AUXB)) {
      break;
    }

    gBS->Stall (50);
    Delay--;
  } while (Delay);

  if (Delay == 0) {
    return EFI_TIMEOUT;
  }

  return EFI_SUCCESS;
}