diff mbox series

[edk2,v2,1/2] ArmPlatformPkg: reorganize PL011 code

Message ID 20171116174708.24964-2-ard.biesheuvel@linaro.org
State Accepted
Commit 12156134fe82e5c574a78898184935c0486b29ad
Headers show
Series ArmplatformPkg: clean up PL011 support library | expand

Commit Message

Ard Biesheuvel Nov. 16, 2017, 5:47 p.m. UTC
The PL011 code in ArmPlatformPkg is organized in a weird way: there is
a single PL011Uart.h header file under Include/Drivers containing both
register definitions and function entry points. The PL011Uart library
itself is in Drivers/ but it is actually a library.

So let's clean this up: add a new PL011UartLib library class and associated
header file containing only the library prototypes, and move the library
itself under Library/ using a new GUID, with the register definitions moved
into a local header file.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

---
 ArmPlatformPkg/ArmPlatformPkg.dec                              |   3 +
 ArmPlatformPkg/Include/Library/PL011UartLib.h                  | 187 ++++++++
 ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortLib.c |   5 +-
 ArmPlatformPkg/Library/PL011UartLib/PL011Uart.h                | 120 +++++
 ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c             | 474 ++++++++++++++++++++
 ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf           |  43 ++
 6 files changed, 829 insertions(+), 3 deletions(-)

-- 
2.11.0

_______________________________________________
edk2-devel mailing list
edk2-devel@lists.01.org
https://lists.01.org/mailman/listinfo/edk2-devel
diff mbox series

Patch

diff --git a/ArmPlatformPkg/ArmPlatformPkg.dec b/ArmPlatformPkg/ArmPlatformPkg.dec
index 2d82ead7612a..e282e76667b1 100644
--- a/ArmPlatformPkg/ArmPlatformPkg.dec
+++ b/ArmPlatformPkg/ArmPlatformPkg.dec
@@ -31,6 +31,9 @@  [Defines]
 [Includes.common]
   Include                        # Root include for the package
 
+[LibraryClasses]
+  PL011UartLib|Include/Library/PL011UartLib.h
+
 [Guids.common]
   gArmPlatformTokenSpaceGuid   = { 0x9c0aaed4, 0x74c5, 0x4043, { 0xb4, 0x17, 0xa3, 0x22, 0x38, 0x14, 0xce, 0x76 } }
   #
diff --git a/ArmPlatformPkg/Include/Library/PL011UartLib.h b/ArmPlatformPkg/Include/Library/PL011UartLib.h
new file mode 100644
index 000000000000..9e923a2218d1
--- /dev/null
+++ b/ArmPlatformPkg/Include/Library/PL011UartLib.h
@@ -0,0 +1,187 @@ 
+/** @file
+*
+*  Copyright (c) 2011-2016, ARM Limited. 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.
+*
+**/
+
+#ifndef __PL011_UART_LIB_H__
+#define __PL011_UART_LIB_H__
+
+#include <Protocol/SerialIo.h>
+
+/**
+
+  Initialise the serial port to the specified settings.
+  All unspecified settings will be set to the default values.
+
+  @param[in]  UartBase            The base address of the serial device.
+  @param[in]  UartClkInHz         The clock in Hz for the serial device.
+                                  Ignored if the PCD PL011UartInteger is not 0
+  @param[in out] BaudRate         The baud rate of the serial device. If the
+                                  baud rate is not supported, the speed will be
+                                  reduced to the nearest supported one and the
+                                  variable's value will be updated accordingly.
+  @param[in out] ReceiveFifoDepth The number of characters the device will
+                                  buffer on input.  Value of 0 will use the
+                                  device's default FIFO depth.
+  @param[in out]  Parity          If applicable, this is the EFI_PARITY_TYPE
+                                  that is computed or checked as each character
+                                  is transmitted or received. If the device
+                                  does not support parity, the value is the
+                                  default parity value.
+  @param[in out]  DataBits        The number of data bits in each character.
+  @param[in out]  StopBits        If applicable, the EFI_STOP_BITS_TYPE number
+                                  of stop bits per character.
+                                  If the device does not support stop bits, the
+                                  value is the default stop bit value.
+
+  @retval RETURN_SUCCESS            All attributes were set correctly on the
+                                    serial device.
+  @retval RETURN_INVALID_PARAMETER  One or more of the attributes has an
+                                    unsupported value.
+
+**/
+RETURN_STATUS
+EFIAPI
+PL011UartInitializePort (
+  IN     UINTN               UartBase,
+  IN     UINT32              UartClkInHz,
+  IN OUT UINT64              *BaudRate,
+  IN OUT UINT32              *ReceiveFifoDepth,
+  IN OUT EFI_PARITY_TYPE     *Parity,
+  IN OUT UINT8               *DataBits,
+  IN OUT EFI_STOP_BITS_TYPE  *StopBits
+  );
+
+/**
+
+  Assert or deassert the control signals on a serial port.
+  The following control signals are set according their bit settings :
+  . Request to Send
+  . Data Terminal Ready
+
+  @param[in]  UartBase  UART registers base address
+  @param[in]  Control   The following bits are taken into account :
+                        . EFI_SERIAL_REQUEST_TO_SEND : assert/deassert the
+                          "Request To Send" control signal if this bit is
+                          equal to one/zero.
+                        . EFI_SERIAL_DATA_TERMINAL_READY : assert/deassert
+                          the "Data Terminal Ready" control signal if this
+                          bit is equal to one/zero.
+                        . EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE : enable/disable
+                          the hardware loopback if this bit is equal to
+                          one/zero.
+                        . EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE : not supported.
+                        . EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE : enable/
+                          disable the hardware flow control based on CTS (Clear
+                          To Send) and RTS (Ready To Send) control signals.
+
+  @retval  RETURN_SUCCESS      The new control bits were set on the device.
+  @retval  RETURN_UNSUPPORTED  The device does not support this operation.
+
+**/
+RETURN_STATUS
+EFIAPI
+PL011UartSetControl (
+  IN UINTN   UartBase,
+  IN UINT32  Control
+  );
+
+/**
+
+  Retrieve the status of the control bits on a serial device.
+
+  @param[in]   UartBase  UART registers base address
+  @param[out]  Control   Status of the control bits on a serial device :
+
+                         . EFI_SERIAL_DATA_CLEAR_TO_SEND,
+                           EFI_SERIAL_DATA_SET_READY,
+                           EFI_SERIAL_RING_INDICATE,
+                           EFI_SERIAL_CARRIER_DETECT,
+                           EFI_SERIAL_REQUEST_TO_SEND,
+                           EFI_SERIAL_DATA_TERMINAL_READY
+                           are all related to the DTE (Data Terminal Equipment)
+                           and DCE (Data Communication Equipment) modes of
+                           operation of the serial device.
+                         . EFI_SERIAL_INPUT_BUFFER_EMPTY : equal to one if the
+                           receive buffer is empty, 0 otherwise.
+                         . EFI_SERIAL_OUTPUT_BUFFER_EMPTY : equal to one if the
+                           transmit buffer is empty, 0 otherwise.
+                         . EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE : equal to one if
+                           the hardware loopback is enabled (the ouput feeds the
+                           receive buffer), 0 otherwise.
+                         . EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE : equal to one if
+                           a loopback is accomplished by software, 0 otherwise.
+                         . EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE : equal to
+                           one if the hardware flow control based on CTS (Clear
+                           To Send) and RTS (Ready To Send) control signals is
+                           enabled, 0 otherwise.
+
+  @retval RETURN_SUCCESS  The control bits were read from the serial device.
+
+**/
+RETURN_STATUS
+EFIAPI
+PL011UartGetControl (
+  IN UINTN     UartBase,
+  OUT UINT32  *Control
+  );
+
+/**
+  Write data to serial device.
+
+  @param  Buffer           Point of data buffer which need to be written.
+  @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
+
+  @retval 0                Write data failed.
+  @retval !0               Actual number of bytes written to serial device.
+
+**/
+UINTN
+EFIAPI
+PL011UartWrite (
+  IN  UINTN       UartBase,
+  IN  UINT8       *Buffer,
+  IN  UINTN       NumberOfBytes
+  );
+
+/**
+  Read data from serial device and save the data in buffer.
+
+  @param  Buffer           Point of data buffer which need to be written.
+  @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
+
+  @retval 0                Read data failed.
+  @retval !0               Actual number of bytes read from serial device.
+
+**/
+UINTN
+EFIAPI
+PL011UartRead (
+  IN  UINTN       UartBase,
+  OUT UINT8       *Buffer,
+  IN  UINTN       NumberOfBytes
+  );
+
+/**
+  Check to see if any data is available to be read from the debug device.
+
+  @retval TRUE       At least one byte of data is available to be read
+  @retval FALSE      No data is available to be read
+
+**/
+BOOLEAN
+EFIAPI
+PL011UartPoll (
+  IN  UINTN       UartBase
+  );
+
+#endif
diff --git a/ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortLib.c b/ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortLib.c
index 571d0618c379..9c54e7880e4c 100644
--- a/ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortLib.c
+++ b/ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortLib.c
@@ -15,14 +15,13 @@ 
 
 **/
 
-#include <Base.h>
+#include <Uefi.h>
 
 #include <Library/IoLib.h>
 #include <Library/PcdLib.h>
+#include <Library/PL011UartLib.h>
 #include <Library/SerialPortLib.h>
 
-#include <Drivers/PL011Uart.h>
-
 /** Initialise the serial device hardware with default settings.
 
   @retval RETURN_SUCCESS            The serial device was initialised.
diff --git a/ArmPlatformPkg/Library/PL011UartLib/PL011Uart.h b/ArmPlatformPkg/Library/PL011UartLib/PL011Uart.h
new file mode 100644
index 000000000000..0ea3855cf3eb
--- /dev/null
+++ b/ArmPlatformPkg/Library/PL011UartLib/PL011Uart.h
@@ -0,0 +1,120 @@ 
+/** @file
+*
+*  Copyright (c) 2011-2016, ARM Limited. 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.
+*
+**/
+
+#ifndef __PL011_UART_H__
+#define __PL011_UART_H__
+
+#define PL011_VARIANT_ZTE 1
+
+// PL011 Registers
+#if FixedPcdGet8 (PL011UartRegOffsetVariant) == PL011_VARIANT_ZTE
+#define UARTDR                    0x004
+#define UARTRSR                   0x010
+#define UARTECR                   0x010
+#define UARTFR                    0x014
+#define UARTIBRD                  0x024
+#define UARTFBRD                  0x028
+#define UARTLCR_H                 0x030
+#define UARTCR                    0x034
+#define UARTIFLS                  0x038
+#define UARTIMSC                  0x040
+#define UARTRIS                   0x044
+#define UARTMIS                   0x048
+#define UARTICR                   0x04c
+#define UARTDMACR                 0x050
+#else
+#define UARTDR                    0x000
+#define UARTRSR                   0x004
+#define UARTECR                   0x004
+#define UARTFR                    0x018
+#define UARTILPR                  0x020
+#define UARTIBRD                  0x024
+#define UARTFBRD                  0x028
+#define UARTLCR_H                 0x02C
+#define UARTCR                    0x030
+#define UARTIFLS                  0x034
+#define UARTIMSC                  0x038
+#define UARTRIS                   0x03C
+#define UARTMIS                   0x040
+#define UARTICR                   0x044
+#define UARTDMACR                 0x048
+#endif
+
+#define UARTPID0                  0xFE0
+#define UARTPID1                  0xFE4
+#define UARTPID2                  0xFE8
+#define UARTPID3                  0xFEC
+
+// Data status bits
+#define UART_DATA_ERROR_MASK      0x0F00
+
+// Status reg bits
+#define UART_STATUS_ERROR_MASK    0x0F
+
+// Flag reg bits
+#if FixedPcdGet8 (PL011UartRegOffsetVariant) == PL011_VARIANT_ZTE
+#define PL011_UARTFR_RI           (1 << 0)  // Ring indicator
+#define PL011_UARTFR_TXFE         (1 << 7)  // Transmit FIFO empty
+#define PL011_UARTFR_RXFF         (1 << 6)  // Receive  FIFO full
+#define PL011_UARTFR_TXFF         (1 << 5)  // Transmit FIFO full
+#define PL011_UARTFR_RXFE         (1 << 4)  // Receive  FIFO empty
+#define PL011_UARTFR_BUSY         (1 << 8)  // UART busy
+#define PL011_UARTFR_DCD          (1 << 2)  // Data carrier detect
+#define PL011_UARTFR_DSR          (1 << 3)  // Data set ready
+#define PL011_UARTFR_CTS          (1 << 1)  // Clear to send
+#else
+#define PL011_UARTFR_RI           (1 << 8)  // Ring indicator
+#define PL011_UARTFR_TXFE         (1 << 7)  // Transmit FIFO empty
+#define PL011_UARTFR_RXFF         (1 << 6)  // Receive  FIFO full
+#define PL011_UARTFR_TXFF         (1 << 5)  // Transmit FIFO full
+#define PL011_UARTFR_RXFE         (1 << 4)  // Receive  FIFO empty
+#define PL011_UARTFR_BUSY         (1 << 3)  // UART busy
+#define PL011_UARTFR_DCD          (1 << 2)  // Data carrier detect
+#define PL011_UARTFR_DSR          (1 << 1)  // Data set ready
+#define PL011_UARTFR_CTS          (1 << 0)  // Clear to send
+#endif
+
+// Flag reg bits - alternative names
+#define UART_TX_EMPTY_FLAG_MASK   PL011_UARTFR_TXFE
+#define UART_RX_FULL_FLAG_MASK    PL011_UARTFR_RXFF
+#define UART_TX_FULL_FLAG_MASK    PL011_UARTFR_TXFF
+#define UART_RX_EMPTY_FLAG_MASK   PL011_UARTFR_RXFE
+#define UART_BUSY_FLAG_MASK       PL011_UARTFR_BUSY
+
+// Control reg bits
+#define PL011_UARTCR_CTSEN        (1 << 15) // CTS hardware flow control enable
+#define PL011_UARTCR_RTSEN        (1 << 14) // RTS hardware flow control enable
+#define PL011_UARTCR_RTS          (1 << 11) // Request to send
+#define PL011_UARTCR_DTR          (1 << 10) // Data transmit ready.
+#define PL011_UARTCR_RXE          (1 << 9)  // Receive enable
+#define PL011_UARTCR_TXE          (1 << 8)  // Transmit enable
+#define PL011_UARTCR_LBE          (1 << 7)  // Loopback enable
+#define PL011_UARTCR_UARTEN       (1 << 0)  // UART Enable
+
+// Line Control Register Bits
+#define PL011_UARTLCR_H_SPS       (1 << 7)  // Stick parity select
+#define PL011_UARTLCR_H_WLEN_8    (3 << 5)
+#define PL011_UARTLCR_H_WLEN_7    (2 << 5)
+#define PL011_UARTLCR_H_WLEN_6    (1 << 5)
+#define PL011_UARTLCR_H_WLEN_5    (0 << 5)
+#define PL011_UARTLCR_H_FEN       (1 << 4)  // FIFOs Enable
+#define PL011_UARTLCR_H_STP2      (1 << 3)  // Two stop bits select
+#define PL011_UARTLCR_H_EPS       (1 << 2)  // Even parity select
+#define PL011_UARTLCR_H_PEN       (1 << 1)  // Parity Enable
+#define PL011_UARTLCR_H_BRK       (1 << 0)  // Send break
+
+#define PL011_UARTPID2_VER(X)     (((X) >> 4) & 0xF)
+#define PL011_VER_R1P4            0x2
+
+#endif
diff --git a/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
new file mode 100644
index 000000000000..61a34fda0b83
--- /dev/null
+++ b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
@@ -0,0 +1,474 @@ 
+/** @file
+  Serial I/O Port library functions with no library constructor/destructor
+
+  Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
+  Copyright (c) 2011 - 2016, ARM 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 <Uefi.h>
+
+#include <Library/DebugLib.h>
+#include <Library/IoLib.h>
+#include <Library/PcdLib.h>
+
+#include <Protocol/SerialIo.h>
+
+#include "PL011Uart.h"
+
+#define FRACTION_PART_SIZE_IN_BITS  6
+#define FRACTION_PART_MASK          ((1 << FRACTION_PART_SIZE_IN_BITS) - 1)
+
+//
+// EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE is the only
+// control bit that is not supported.
+//
+STATIC CONST UINT32 mInvalidControlBits = EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE;
+
+/**
+
+  Initialise the serial port to the specified settings.
+  The serial port is re-configured only if the specified settings
+  are different from the current settings.
+  All unspecified settings will be set to the default values.
+
+  @param  UartBase                The base address of the serial device.
+  @param  UartClkInHz             The clock in Hz for the serial device.
+                                  Ignored if the PCD PL011UartInteger is not 0
+  @param  BaudRate                The baud rate of the serial device. If the
+                                  baud rate is not supported, the speed will be
+                                  reduced to the nearest supported one and the
+                                  variable's value will be updated accordingly.
+  @param  ReceiveFifoDepth        The number of characters the device will
+                                  buffer on input.  Value of 0 will use the
+                                  device's default FIFO depth.
+  @param  Parity                  If applicable, this is the EFI_PARITY_TYPE
+                                  that is computed or checked as each character
+                                  is transmitted or received. If the device
+                                  does not support parity, the value is the
+                                  default parity value.
+  @param  DataBits                The number of data bits in each character.
+  @param  StopBits                If applicable, the EFI_STOP_BITS_TYPE number
+                                  of stop bits per character.
+                                  If the device does not support stop bits, the
+                                  value is the default stop bit value.
+
+  @retval RETURN_SUCCESS            All attributes were set correctly on the
+                                    serial device.
+  @retval RETURN_INVALID_PARAMETER  One or more of the attributes has an
+                                    unsupported value.
+
+**/
+RETURN_STATUS
+EFIAPI
+PL011UartInitializePort (
+  IN     UINTN               UartBase,
+  IN     UINT32              UartClkInHz,
+  IN OUT UINT64              *BaudRate,
+  IN OUT UINT32              *ReceiveFifoDepth,
+  IN OUT EFI_PARITY_TYPE     *Parity,
+  IN OUT UINT8               *DataBits,
+  IN OUT EFI_STOP_BITS_TYPE  *StopBits
+  )
+{
+  UINT32      LineControl;
+  UINT32      Divisor;
+  UINT32      Integer;
+  UINT32      Fractional;
+  UINT32      HardwareFifoDepth;
+
+  HardwareFifoDepth = (PL011_UARTPID2_VER (MmioRead32 (UartBase + UARTPID2)) \
+                       > PL011_VER_R1P4) \
+                      ? 32 : 16 ;
+  // The PL011 supports a buffer of 1, 16 or 32 chars. Therefore we can accept
+  // 1 char buffer as the minimum FIFO size. Because everything can be rounded
+  // down, there is no maximum FIFO size.
+  if ((*ReceiveFifoDepth == 0) || (*ReceiveFifoDepth >= HardwareFifoDepth)) {
+    // Enable FIFO
+    LineControl = PL011_UARTLCR_H_FEN;
+    *ReceiveFifoDepth = HardwareFifoDepth;
+  } else {
+    // Disable FIFO
+    LineControl = 0;
+    // Nothing else to do. 1 byte FIFO is default.
+    *ReceiveFifoDepth = 1;
+  }
+
+  //
+  // Parity
+  //
+  switch (*Parity) {
+  case DefaultParity:
+    *Parity = NoParity;
+  case NoParity:
+    // Nothing to do. Parity is disabled by default.
+    break;
+  case EvenParity:
+    LineControl |= (PL011_UARTLCR_H_PEN | PL011_UARTLCR_H_EPS);
+    break;
+  case OddParity:
+    LineControl |= PL011_UARTLCR_H_PEN;
+    break;
+  case MarkParity:
+    LineControl |= (  PL011_UARTLCR_H_PEN \
+                    | PL011_UARTLCR_H_SPS \
+                    | PL011_UARTLCR_H_EPS);
+    break;
+  case SpaceParity:
+    LineControl |= (PL011_UARTLCR_H_PEN | PL011_UARTLCR_H_SPS);
+    break;
+  default:
+    return RETURN_INVALID_PARAMETER;
+  }
+
+  //
+  // Data Bits
+  //
+  switch (*DataBits) {
+  case 0:
+    *DataBits = 8;
+  case 8:
+    LineControl |= PL011_UARTLCR_H_WLEN_8;
+    break;
+  case 7:
+    LineControl |= PL011_UARTLCR_H_WLEN_7;
+    break;
+  case 6:
+    LineControl |= PL011_UARTLCR_H_WLEN_6;
+    break;
+  case 5:
+    LineControl |= PL011_UARTLCR_H_WLEN_5;
+    break;
+  default:
+    return RETURN_INVALID_PARAMETER;
+  }
+
+  //
+  // Stop Bits
+  //
+  switch (*StopBits) {
+  case DefaultStopBits:
+    *StopBits = OneStopBit;
+  case OneStopBit:
+    // Nothing to do. One stop bit is enabled by default.
+    break;
+  case TwoStopBits:
+    LineControl |= PL011_UARTLCR_H_STP2;
+    break;
+  case OneFiveStopBits:
+    // Only 1 or 2 stop bits are supported
+  default:
+    return RETURN_INVALID_PARAMETER;
+  }
+
+  // Don't send the LineControl value to the PL011 yet,
+  // wait until after the Baud Rate setting.
+  // This ensures we do not mess up the UART settings halfway through
+  // in the rare case when there is an error with the Baud Rate.
+
+  //
+  // Baud Rate
+  //
+
+  // If PL011 Integer value has been defined then always ignore the BAUD rate
+  if (FixedPcdGet32 (PL011UartInteger) != 0) {
+    Integer = FixedPcdGet32 (PL011UartInteger);
+    Fractional = FixedPcdGet32 (PL011UartFractional);
+  } else {
+    // If BAUD rate is zero then replace it with the system default value
+    if (*BaudRate == 0) {
+      *BaudRate = FixedPcdGet32 (PcdSerialBaudRate);
+      if (*BaudRate == 0) {
+        return RETURN_INVALID_PARAMETER;
+      }
+    }
+    if (0 == UartClkInHz) {
+      return RETURN_INVALID_PARAMETER;
+    }
+
+    Divisor = (UartClkInHz * 4) / *BaudRate;
+    Integer = Divisor >> FRACTION_PART_SIZE_IN_BITS;
+    Fractional = Divisor & FRACTION_PART_MASK;
+  }
+
+  //
+  // If PL011 is already initialized, check the current settings
+  // and re-initialize only if the settings are different.
+  //
+  if (((MmioRead32 (UartBase + UARTCR) & PL011_UARTCR_UARTEN) != 0) &&
+       (MmioRead32 (UartBase + UARTLCR_H) == LineControl) &&
+       (MmioRead32 (UartBase + UARTIBRD) == Integer) &&
+       (MmioRead32 (UartBase + UARTFBRD) == Fractional)) {
+    // Nothing to do - already initialized with correct attributes
+    return RETURN_SUCCESS;
+  }
+
+  // Wait for the end of transmission
+  while ((MmioRead32 (UartBase + UARTFR) & PL011_UARTFR_TXFE) == 0);
+
+  // Disable UART: "The UARTLCR_H, UARTIBRD, and UARTFBRD registers must not be changed
+  // when the UART is enabled"
+  MmioWrite32 (UartBase + UARTCR, 0);
+
+  // Set Baud Rate Registers
+  MmioWrite32 (UartBase + UARTIBRD, Integer);
+  MmioWrite32 (UartBase + UARTFBRD, Fractional);
+
+  // No parity, 1 stop, no fifo, 8 data bits
+  MmioWrite32 (UartBase + UARTLCR_H, LineControl);
+
+  // Clear any pending errors
+  MmioWrite32 (UartBase + UARTECR, 0);
+
+  // Enable Tx, Rx, and UART overall
+  MmioWrite32 (UartBase + UARTCR,
+               PL011_UARTCR_RXE | PL011_UARTCR_TXE | PL011_UARTCR_UARTEN);
+
+  return RETURN_SUCCESS;
+}
+
+/**
+
+  Assert or deassert the control signals on a serial port.
+  The following control signals are set according their bit settings :
+  . Request to Send
+  . Data Terminal Ready
+
+  @param[in]  UartBase  UART registers base address
+  @param[in]  Control   The following bits are taken into account :
+                        . EFI_SERIAL_REQUEST_TO_SEND : assert/deassert the
+                          "Request To Send" control signal if this bit is
+                          equal to one/zero.
+                        . EFI_SERIAL_DATA_TERMINAL_READY : assert/deassert
+                          the "Data Terminal Ready" control signal if this
+                          bit is equal to one/zero.
+                        . EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE : enable/disable
+                          the hardware loopback if this bit is equal to
+                          one/zero.
+                        . EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE : not supported.
+                        . EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE : enable/
+                          disable the hardware flow control based on CTS (Clear
+                          To Send) and RTS (Ready To Send) control signals.
+
+  @retval  RETURN_SUCCESS      The new control bits were set on the device.
+  @retval  RETURN_UNSUPPORTED  The device does not support this operation.
+
+**/
+RETURN_STATUS
+EFIAPI
+PL011UartSetControl (
+    IN UINTN   UartBase,
+    IN UINT32  Control
+  )
+{
+  UINT32  Bits;
+
+  if (Control & (mInvalidControlBits)) {
+    return RETURN_UNSUPPORTED;
+  }
+
+  Bits = MmioRead32 (UartBase + UARTCR);
+
+  if (Control & EFI_SERIAL_REQUEST_TO_SEND) {
+    Bits |= PL011_UARTCR_RTS;
+  } else {
+    Bits &= ~PL011_UARTCR_RTS;
+  }
+
+  if (Control & EFI_SERIAL_DATA_TERMINAL_READY) {
+    Bits |= PL011_UARTCR_DTR;
+  } else {
+    Bits &= ~PL011_UARTCR_DTR;
+  }
+
+  if (Control & EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE) {
+    Bits |= PL011_UARTCR_LBE;
+  } else {
+    Bits &= ~PL011_UARTCR_LBE;
+  }
+
+  if (Control & EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE) {
+    Bits |= (PL011_UARTCR_CTSEN | PL011_UARTCR_RTSEN);
+  } else {
+    Bits &= ~(PL011_UARTCR_CTSEN | PL011_UARTCR_RTSEN);
+  }
+
+  MmioWrite32 (UartBase + UARTCR, Bits);
+
+  return RETURN_SUCCESS;
+}
+
+/**
+
+  Retrieve the status of the control bits on a serial device.
+
+  @param[in]   UartBase  UART registers base address
+  @param[out]  Control   Status of the control bits on a serial device :
+
+                         . EFI_SERIAL_DATA_CLEAR_TO_SEND,
+                           EFI_SERIAL_DATA_SET_READY,
+                           EFI_SERIAL_RING_INDICATE,
+                           EFI_SERIAL_CARRIER_DETECT,
+                           EFI_SERIAL_REQUEST_TO_SEND,
+                           EFI_SERIAL_DATA_TERMINAL_READY
+                           are all related to the DTE (Data Terminal Equipment)
+                           and DCE (Data Communication Equipment) modes of
+                           operation of the serial device.
+                         . EFI_SERIAL_INPUT_BUFFER_EMPTY : equal to one if the
+                           receive buffer is empty, 0 otherwise.
+                         . EFI_SERIAL_OUTPUT_BUFFER_EMPTY : equal to one if the
+                           transmit buffer is empty, 0 otherwise.
+                         . EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE : equal to one if
+                           the hardware loopback is enabled (the ouput feeds the
+                           receive buffer), 0 otherwise.
+                         . EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE : equal to one if
+                           a loopback is accomplished by software, 0 otherwise.
+                         . EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE : equal to
+                           one if the hardware flow control based on CTS (Clear
+                           To Send) and RTS (Ready To Send) control signals is
+                           enabled, 0 otherwise.
+
+  @retval RETURN_SUCCESS  The control bits were read from the serial device.
+
+**/
+RETURN_STATUS
+EFIAPI
+PL011UartGetControl (
+    IN UINTN     UartBase,
+    OUT UINT32  *Control
+  )
+{
+  UINT32      FlagRegister;
+  UINT32      ControlRegister;
+
+
+  FlagRegister = MmioRead32 (UartBase + UARTFR);
+  ControlRegister = MmioRead32 (UartBase + UARTCR);
+
+  *Control = 0;
+
+  if ((FlagRegister & PL011_UARTFR_CTS) == PL011_UARTFR_CTS) {
+    *Control |= EFI_SERIAL_CLEAR_TO_SEND;
+  }
+
+  if ((FlagRegister & PL011_UARTFR_DSR) == PL011_UARTFR_DSR) {
+    *Control |= EFI_SERIAL_DATA_SET_READY;
+  }
+
+  if ((FlagRegister & PL011_UARTFR_RI) == PL011_UARTFR_RI) {
+    *Control |= EFI_SERIAL_RING_INDICATE;
+  }
+
+  if ((FlagRegister & PL011_UARTFR_DCD) == PL011_UARTFR_DCD) {
+    *Control |= EFI_SERIAL_CARRIER_DETECT;
+  }
+
+  if ((ControlRegister & PL011_UARTCR_RTS) == PL011_UARTCR_RTS) {
+    *Control |= EFI_SERIAL_REQUEST_TO_SEND;
+  }
+
+  if ((ControlRegister & PL011_UARTCR_DTR) == PL011_UARTCR_DTR) {
+    *Control |= EFI_SERIAL_DATA_TERMINAL_READY;
+  }
+
+  if ((FlagRegister & PL011_UARTFR_RXFE) == PL011_UARTFR_RXFE) {
+    *Control |= EFI_SERIAL_INPUT_BUFFER_EMPTY;
+  }
+
+  if ((FlagRegister & PL011_UARTFR_TXFE) == PL011_UARTFR_TXFE) {
+    *Control |= EFI_SERIAL_OUTPUT_BUFFER_EMPTY;
+  }
+
+  if ((ControlRegister & (PL011_UARTCR_CTSEN | PL011_UARTCR_RTSEN))
+       == (PL011_UARTCR_CTSEN | PL011_UARTCR_RTSEN)) {
+    *Control |= EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE;
+  }
+
+  if ((ControlRegister & PL011_UARTCR_LBE) == PL011_UARTCR_LBE) {
+    *Control |= EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE;
+  }
+
+  return RETURN_SUCCESS;
+}
+
+/**
+  Write data to serial device.
+
+  @param  Buffer           Point of data buffer which need to be written.
+  @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
+
+  @retval 0                Write data failed.
+  @retval !0               Actual number of bytes written to serial device.
+
+**/
+UINTN
+EFIAPI
+PL011UartWrite (
+  IN  UINTN    UartBase,
+  IN UINT8     *Buffer,
+  IN UINTN     NumberOfBytes
+  )
+{
+  UINT8* CONST Final = &Buffer[NumberOfBytes];
+
+  while (Buffer < Final) {
+    // Wait until UART able to accept another char
+    while ((MmioRead32 (UartBase + UARTFR) & UART_TX_FULL_FLAG_MASK));
+
+    MmioWrite8 (UartBase + UARTDR, *Buffer++);
+  }
+
+  return NumberOfBytes;
+}
+
+/**
+  Read data from serial device and save the data in buffer.
+
+  @param  Buffer           Point of data buffer which need to be written.
+  @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
+
+  @retval 0                Read data failed.
+  @retval !0               Actual number of bytes read from serial device.
+
+**/
+UINTN
+EFIAPI
+PL011UartRead (
+  IN  UINTN     UartBase,
+  OUT UINT8     *Buffer,
+  IN  UINTN     NumberOfBytes
+  )
+{
+  UINTN   Count;
+
+  for (Count = 0; Count < NumberOfBytes; Count++, Buffer++) {
+    while ((MmioRead32 (UartBase + UARTFR) & UART_RX_EMPTY_FLAG_MASK) != 0);
+    *Buffer = MmioRead8 (UartBase + UARTDR);
+  }
+
+  return NumberOfBytes;
+}
+
+/**
+  Check to see if any data is available to be read from the debug device.
+
+  @retval TRUE       At least one byte of data is available to be read
+  @retval FALSE      No data is available to be read
+
+**/
+BOOLEAN
+EFIAPI
+PL011UartPoll (
+  IN  UINTN     UartBase
+  )
+{
+  return ((MmioRead32 (UartBase + UARTFR) & UART_RX_EMPTY_FLAG_MASK) == 0);
+}
diff --git a/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf
new file mode 100644
index 000000000000..4fc974494a33
--- /dev/null
+++ b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf
@@ -0,0 +1,43 @@ 
+#/** @file
+#
+#  Component description file for PL011Uart module
+#
+#  Copyright (c) 2011-2016, ARM 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                    = 0x00010005
+  BASE_NAME                      = PL011UartLib
+  FILE_GUID                      = 6a2c5714-8910-44f0-861f-804abc18ce39
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = PL011UartLib
+
+[Sources.common]
+  PL011Uart.h
+  PL011UartLib.c
+
+[LibraryClasses]
+  DebugLib
+  IoLib
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+  ArmPlatformPkg/ArmPlatformPkg.dec
+
+[FixedPcd]
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialBaudRate
+
+  gArmPlatformTokenSpaceGuid.PL011UartInteger
+  gArmPlatformTokenSpaceGuid.PL011UartFractional
+  gArmPlatformTokenSpaceGuid.PL011UartRegOffsetVariant