CorebootModulePkg: Add BaseSerialPortLib16550

Copy MdeModulePkg/Library/BaseSerialPortLib16550 revision
89ecd4cf8078aa946083cdcbf9af81ff29f8d9f5.

Change-Id: Ie2fd0123bdd7aaba4335afdb1cb017f3690455c6
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-by: Prince Agyeman <prince.agyeman@intel.com>

3 files changed, 1164 insertions, 0 deletions

diff --git a/CorebootModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.c b/CorebootModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.c
new file mode 100644
index 0000000000..25ca822eb7
--- /dev/null
+++ b/CorebootModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.c
@@ -0,0 +1,1094 @@
+/** @file
+  16550 UART Serial Port library functions
+
+  (C) Copyright 2014 Hewlett-Packard Development Company, L.P.<BR>
+  Copyright (c) 2006 - 2016, Intel Corporation. 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 <Base.h>
+#include <IndustryStandard/Pci.h>
+#include <Library/SerialPortLib.h>
+#include <Library/PcdLib.h>
+#include <Library/IoLib.h>
+#include <Library/PciLib.h>
+#include <Library/PlatformHookLib.h>
+#include <Library/BaseLib.h>
+
+//
+// PCI Defintions.
+//
+#define PCI_BRIDGE_32_BIT_IO_SPACE              0x01
+
+//
+// 16550 UART register offsets and bitfields
+//
+#define R_UART_RXBUF          0
+#define R_UART_TXBUF          0
+#define R_UART_BAUD_LOW       0
+#define R_UART_BAUD_HIGH      1
+#define R_UART_FCR            2
+#define   B_UART_FCR_FIFOE    BIT0
+#define   B_UART_FCR_FIFO64   BIT5
+#define R_UART_LCR            3
+#define   B_UART_LCR_DLAB     BIT7
+#define R_UART_MCR            4
+#define   B_UART_MCR_DTRC     BIT0
+#define   B_UART_MCR_RTS      BIT1
+#define R_UART_LSR            5
+#define   B_UART_LSR_RXRDY    BIT0
+#define   B_UART_LSR_TXRDY    BIT5
+#define   B_UART_LSR_TEMT     BIT6
+#define R_UART_MSR            6
+#define   B_UART_MSR_CTS      BIT4
+#define   B_UART_MSR_DSR      BIT5
+#define   B_UART_MSR_RI       BIT6
+#define   B_UART_MSR_DCD      BIT7
+
+//
+// 4-byte structure for each PCI node in PcdSerialPciDeviceInfo
+//
+typedef struct {
+  UINT8   Device;
+  UINT8   Function;
+  UINT16  PowerManagementStatusAndControlRegister;
+} PCI_UART_DEVICE_INFO;
+
+/**
+  Read an 8-bit 16550 register.  If PcdSerialUseMmio is TRUE, then the value is read from 
+  MMIO space.  If PcdSerialUseMmio is FALSE, then the value is read from I/O space.  The
+  parameter Offset is added to the base address of the 16550 registers that is specified 
+  by PcdSerialRegisterBase. 
+  
+  @param  Base    The base address register of UART device.
+  @param  Offset  The offset of the 16550 register to read.
+
+  @return The value read from the 16550 register.
+
+**/
+UINT8
+SerialPortReadRegister (
+  UINTN  Base,
+  UINTN  Offset
+  )
+{
+  if (PcdGetBool (PcdSerialUseMmio)) {
+    return MmioRead8 (Base + Offset * PcdGet32 (PcdSerialRegisterStride));
+  } else {
+    return IoRead8 (Base + Offset * PcdGet32 (PcdSerialRegisterStride));
+  }
+}
+
+/**
+  Write an 8-bit 16550 register.  If PcdSerialUseMmio is TRUE, then the value is written to
+  MMIO space.  If PcdSerialUseMmio is FALSE, then the value is written to I/O space.  The
+  parameter Offset is added to the base address of the 16550 registers that is specified 
+  by PcdSerialRegisterBase. 
+  
+  @param  Base    The base address register of UART device.
+  @param  Offset  The offset of the 16550 register to write.
+  @param  Value   The value to write to the 16550 register specified by Offset.
+
+  @return The value written to the 16550 register.
+
+**/
+UINT8
+SerialPortWriteRegister (
+  UINTN  Base,
+  UINTN  Offset,
+  UINT8  Value
+  )
+{
+  if (PcdGetBool (PcdSerialUseMmio)) {
+    return MmioWrite8 (Base + Offset * PcdGet32 (PcdSerialRegisterStride), Value);
+  } else {
+    return IoWrite8 (Base + Offset * PcdGet32 (PcdSerialRegisterStride), Value);
+  }
+}
+
+/**
+  Update the value of an 16-bit PCI configuration register in a PCI device.  If the  
+  PCI Configuration register specified by PciAddress is already programmed with a 
+  non-zero value, then return the current value.  Otherwise update the PCI configuration 
+  register specified by PciAddress with the value specified by Value and return the
+  value programmed into the PCI configuration register.  All values must be masked 
+  using the bitmask specified by Mask.
+
+  @param  PciAddress  PCI Library address of the PCI Configuration register to update.
+  @param  Value       The value to program into the PCI Configuration Register.
+  @param  Mask        Bitmask of the bits to check and update in the PCI configuration register.
+
+**/
+UINT16
+SerialPortLibUpdatePciRegister16 (
+  UINTN   PciAddress,
+  UINT16  Value,
+  UINT16  Mask
+  )
+{
+  UINT16  CurrentValue;
+  
+  CurrentValue = PciRead16 (PciAddress) & Mask;
+  if (CurrentValue != 0) {
+    return CurrentValue;
+  }
+  return PciWrite16 (PciAddress, Value & Mask);
+}
+
+/**
+  Update the value of an 32-bit PCI configuration register in a PCI device.  If the  
+  PCI Configuration register specified by PciAddress is already programmed with a 
+  non-zero value, then return the current value.  Otherwise update the PCI configuration 
+  register specified by PciAddress with the value specified by Value and return the
+  value programmed into the PCI configuration register.  All values must be masked 
+  using the bitmask specified by Mask.
+
+  @param  PciAddress  PCI Library address of the PCI Configuration register to update.
+  @param  Value       The value to program into the PCI Configuration Register.
+  @param  Mask        Bitmask of the bits to check and update in the PCI configuration register.
+
+  @return  The Secondary bus number that is actually programed into the PCI to PCI Bridge device.
+
+**/
+UINT32
+SerialPortLibUpdatePciRegister32 (
+  UINTN   PciAddress,
+  UINT32  Value,
+  UINT32  Mask
+  )
+{
+  UINT32  CurrentValue;
+  
+  CurrentValue = PciRead32 (PciAddress) & Mask;
+  if (CurrentValue != 0) {
+    return CurrentValue;
+  }
+  return PciWrite32 (PciAddress, Value & Mask);
+}
+
+/**
+  Retrieve the I/O or MMIO base address register for the PCI UART device. 
+  
+  This function assumes Root Bus Numer is Zero, and enables I/O and MMIO in PCI UART 
+  Device if they are not already enabled. 
+  
+  @return  The base address register of the UART device.
+
+**/
+UINTN
+GetSerialRegisterBase (
+  VOID
+  )
+{
+  UINTN                 PciLibAddress;
+  UINTN                 BusNumber;
+  UINTN                 SubordinateBusNumber;
+  UINT32                ParentIoBase;
+  UINT32                ParentIoLimit;
+  UINT16                ParentMemoryBase;
+  UINT16                ParentMemoryLimit;
+  UINT32                IoBase;
+  UINT32                IoLimit;
+  UINT16                MemoryBase;
+  UINT16                MemoryLimit;
+  UINTN                 SerialRegisterBase;
+  UINTN                 BarIndex;
+  UINT32                RegisterBaseMask;
+  PCI_UART_DEVICE_INFO  *DeviceInfo;
+
+  //
+  // Get PCI Device Info
+  //
+  DeviceInfo = (PCI_UART_DEVICE_INFO *) PcdGetPtr (PcdSerialPciDeviceInfo);
+  
+  //
+  // If PCI Device Info is empty, then assume fixed address UART and return PcdSerialRegisterBase
+  //  
+  if (DeviceInfo->Device == 0xff) {
+    return (UINTN)PcdGet64 (PcdSerialRegisterBase);
+  }
+
+  //
+  // Assume PCI Bus 0 I/O window is 0-64KB and MMIO windows is 0-4GB
+  //
+  ParentMemoryBase  = 0 >> 16;
+  ParentMemoryLimit = 0xfff00000 >> 16;
+  ParentIoBase      = 0 >> 12;
+  ParentIoLimit     = 0xf000 >> 12;
+  
+  //
+  // Enable I/O and MMIO in PCI Bridge
+  // Assume Root Bus Numer is Zero. 
+  //
+  for (BusNumber = 0; (DeviceInfo + 1)->Device != 0xff; DeviceInfo++) {
+    //
+    // Compute PCI Lib Address to PCI to PCI Bridge
+    //
+    PciLibAddress = PCI_LIB_ADDRESS (BusNumber, DeviceInfo->Device, DeviceInfo->Function, 0);
+    
+    //
+    // Retrieve and verify the bus numbers in the PCI to PCI Bridge
+    //
+    BusNumber            = PciRead8 (PciLibAddress + PCI_BRIDGE_SECONDARY_BUS_REGISTER_OFFSET);
+    SubordinateBusNumber = PciRead8 (PciLibAddress + PCI_BRIDGE_SUBORDINATE_BUS_REGISTER_OFFSET);
+    if (BusNumber == 0 || BusNumber > SubordinateBusNumber) {
+      return 0;
+    }
+
+    //
+    // Retrieve and verify the I/O or MMIO decode window in the PCI to PCI Bridge
+    //
+    if (PcdGetBool (PcdSerialUseMmio)) {
+      MemoryLimit = PciRead16 (PciLibAddress + OFFSET_OF (PCI_TYPE01, Bridge.MemoryLimit)) & 0xfff0;
+      MemoryBase  = PciRead16 (PciLibAddress + OFFSET_OF (PCI_TYPE01, Bridge.MemoryBase))  & 0xfff0;
+
+      //
+      // If PCI Bridge MMIO window is disabled, then return 0
+      //
+      if (MemoryLimit < MemoryBase) {
+        return 0;
+      }
+      
+      //
+      // If PCI Bridge MMIO window is not in the address range decoded by the parent PCI Bridge, then return 0
+      //  
+      if (MemoryBase < ParentMemoryBase || MemoryBase > ParentMemoryLimit || MemoryLimit > ParentMemoryLimit) {
+        return 0;
+      }
+      ParentMemoryBase  = MemoryBase;
+      ParentMemoryLimit = MemoryLimit;
+    } else {
+      IoLimit = PciRead8 (PciLibAddress + OFFSET_OF (PCI_TYPE01, Bridge.IoLimit));
+      if ((IoLimit & PCI_BRIDGE_32_BIT_IO_SPACE ) == 0) {
+        IoLimit = IoLimit >> 4;
+      } else {
+        IoLimit = (PciRead16 (PciLibAddress + OFFSET_OF (PCI_TYPE01, Bridge.IoLimitUpper16)) << 4) | (IoLimit >> 4);
+      }
+      IoBase = PciRead8 (PciLibAddress + OFFSET_OF (PCI_TYPE01, Bridge.IoBase));
+      if ((IoBase & PCI_BRIDGE_32_BIT_IO_SPACE ) == 0) {
+        IoBase = IoBase >> 4;
+      } else {
+        IoBase = (PciRead16 (PciLibAddress + OFFSET_OF (PCI_TYPE01, Bridge.IoBaseUpper16)) << 4) | (IoBase >> 4);
+      }
+      
+      //
+      // If PCI Bridge I/O window is disabled, then return 0
+      //
+      if (IoLimit < IoBase) {
+        return 0;
+      }
+      
+      //
+      // If PCI Bridge I/O window is not in the address range decoded by the parent PCI Bridge, then return 0
+      //  
+      if (IoBase < ParentIoBase || IoBase > ParentIoLimit || IoLimit > ParentIoLimit) {
+        return 0;
+      }
+      ParentIoBase  = IoBase;
+      ParentIoLimit = IoLimit;
+    }
+  }
+
+  //
+  // Compute PCI Lib Address to PCI UART
+  //
+  PciLibAddress = PCI_LIB_ADDRESS (BusNumber, DeviceInfo->Device, DeviceInfo->Function, 0);
+  
+  //
+  // Find the first IO or MMIO BAR
+  //
+  RegisterBaseMask = 0xFFFFFFF0;
+  for (BarIndex = 0; BarIndex < PCI_MAX_BAR; BarIndex ++) {
+    SerialRegisterBase = PciRead32 (PciLibAddress + PCI_BASE_ADDRESSREG_OFFSET + BarIndex * 4);
+    if (PcdGetBool (PcdSerialUseMmio) && ((SerialRegisterBase & BIT0) == 0)) {
+      //
+      // MMIO BAR is found
+      //
+      RegisterBaseMask = 0xFFFFFFF0;
+      break;
+    }
+
+    if ((!PcdGetBool (PcdSerialUseMmio)) && ((SerialRegisterBase & BIT0) != 0)) {
+      //
+      // IO BAR is found
+      //
+      RegisterBaseMask = 0xFFFFFFF8;
+      break;
+    }
+  }
+
+  //
+  // MMIO or IO BAR is not found.
+  //
+  if (BarIndex == PCI_MAX_BAR) {
+    return 0;
+  }
+
+  //
+  // Program UART BAR
+  //  
+  SerialRegisterBase = SerialPortLibUpdatePciRegister32 (
+                         PciLibAddress + PCI_BASE_ADDRESSREG_OFFSET + BarIndex * 4,
+                         (UINT32)PcdGet64 (PcdSerialRegisterBase), 
+                         RegisterBaseMask
+                         );
+
+  //
+  // Verify that the UART BAR is in the address range decoded by the parent PCI Bridge
+  //  
+  if (PcdGetBool (PcdSerialUseMmio)) {
+    if (((SerialRegisterBase >> 16) & 0xfff0) < ParentMemoryBase || ((SerialRegisterBase >> 16) & 0xfff0) > ParentMemoryLimit) {
+      return 0;
+    }
+  } else {
+    if ((SerialRegisterBase >> 12) < ParentIoBase || (SerialRegisterBase >> 12) > ParentIoLimit) {
+      return 0;
+    }
+  }
+  
+  //
+  // Enable I/O and MMIO in PCI UART Device if they are not already enabled
+  //
+  PciOr16 (
+    PciLibAddress + PCI_COMMAND_OFFSET,
+    PcdGetBool (PcdSerialUseMmio) ? EFI_PCI_COMMAND_MEMORY_SPACE : EFI_PCI_COMMAND_IO_SPACE
+    );
+
+  //
+  // Force D0 state if a Power Management and Status Register is specified
+  //
+  if (DeviceInfo->PowerManagementStatusAndControlRegister != 0x00) {
+    if ((PciRead16 (PciLibAddress + DeviceInfo->PowerManagementStatusAndControlRegister) & (BIT0 | BIT1)) != 0x00) {
+      PciAnd16 (PciLibAddress + DeviceInfo->PowerManagementStatusAndControlRegister, (UINT16)~(BIT0 | BIT1));
+      //
+      // If PCI UART was not in D0, then make sure FIFOs are enabled, but do not reset FIFOs
+      //
+      SerialPortWriteRegister (SerialRegisterBase, R_UART_FCR, (UINT8)(PcdGet8 (PcdSerialFifoControl) & (B_UART_FCR_FIFOE | B_UART_FCR_FIFO64)));
+    }
+  }
+  
+  //
+  // Get PCI Device Info
+  //
+  DeviceInfo = (PCI_UART_DEVICE_INFO *) PcdGetPtr (PcdSerialPciDeviceInfo);
+
+  //
+  // Enable I/O or MMIO in PCI Bridge
+  // Assume Root Bus Numer is Zero. 
+  //
+  for (BusNumber = 0; (DeviceInfo + 1)->Device != 0xff; DeviceInfo++) {
+    //
+    // Compute PCI Lib Address to PCI to PCI Bridge
+    //
+    PciLibAddress = PCI_LIB_ADDRESS (BusNumber, DeviceInfo->Device, DeviceInfo->Function, 0);
+    
+    //
+    // Enable the I/O or MMIO decode windows in the PCI to PCI Bridge
+    //
+    PciOr16 (
+      PciLibAddress + PCI_COMMAND_OFFSET, 
+      PcdGetBool (PcdSerialUseMmio) ? EFI_PCI_COMMAND_MEMORY_SPACE : EFI_PCI_COMMAND_IO_SPACE
+      );
+      
+    //
+    // Force D0 state if a Power Management and Status Register is specified
+    //
+    if (DeviceInfo->PowerManagementStatusAndControlRegister != 0x00) {
+      if ((PciRead16 (PciLibAddress + DeviceInfo->PowerManagementStatusAndControlRegister) & (BIT0 | BIT1)) != 0x00) {
+        PciAnd16 (PciLibAddress + DeviceInfo->PowerManagementStatusAndControlRegister, (UINT16)~(BIT0 | BIT1));
+      }
+    }
+      
+    BusNumber = PciRead8 (PciLibAddress + PCI_BRIDGE_SECONDARY_BUS_REGISTER_OFFSET);
+  }
+  
+  return SerialRegisterBase;
+}
+
+/**
+  Return whether the hardware flow control signal allows writing.
+
+  @param  SerialRegisterBase The base address register of UART device.
+
+  @retval TRUE  The serial port is writable.
+  @retval FALSE The serial port is not writable.
+**/
+BOOLEAN
+SerialPortWritable (
+  UINTN  SerialRegisterBase
+  )
+{
+  if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+    if (PcdGetBool (PcdSerialDetectCable)) {
+      //
+      // Wait for both DSR and CTS to be set
+      //   DSR is set if a cable is connected.
+      //   CTS is set if it is ok to transmit data
+      //
+      //   DSR  CTS  Description                               Action
+      //   ===  ===  ========================================  ========
+      //    0    0   No cable connected.                       Wait
+      //    0    1   No cable connected.                       Wait
+      //    1    0   Cable connected, but not clear to send.   Wait
+      //    1    1   Cable connected, and clear to send.       Transmit
+      //
+      return (BOOLEAN) ((SerialPortReadRegister (SerialRegisterBase, R_UART_MSR) & (B_UART_MSR_DSR | B_UART_MSR_CTS)) == (B_UART_MSR_DSR | B_UART_MSR_CTS));
+    } else {
+      //
+      // Wait for both DSR and CTS to be set OR for DSR to be clear.  
+      //   DSR is set if a cable is connected.
+      //   CTS is set if it is ok to transmit data
+      //
+      //   DSR  CTS  Description                               Action
+      //   ===  ===  ========================================  ========
+      //    0    0   No cable connected.                       Transmit
+      //    0    1   No cable connected.                       Transmit
+      //    1    0   Cable connected, but not clear to send.   Wait
+      //    1    1   Cable connected, and clar to send.        Transmit
+      //
+      return (BOOLEAN) ((SerialPortReadRegister (SerialRegisterBase, R_UART_MSR) & (B_UART_MSR_DSR | B_UART_MSR_CTS)) != (B_UART_MSR_DSR));
+    }
+  }
+
+  return TRUE;
+}
+
+/**
+  Initialize the serial device hardware.
+  
+  If no initialization is required, then return RETURN_SUCCESS.
+  If the serial device was successfully initialized, then return RETURN_SUCCESS.
+  If the serial device could not be initialized, then return RETURN_DEVICE_ERROR.
+  
+  @retval RETURN_SUCCESS        The serial device was initialized.
+  @retval RETURN_DEVICE_ERROR   The serial device could not be initialized.
+
+**/
+RETURN_STATUS
+EFIAPI
+SerialPortInitialize (
+  VOID
+  )
+{
+  RETURN_STATUS  Status;
+  UINTN          SerialRegisterBase;
+  UINT32         Divisor;
+  UINT32         CurrentDivisor;  
+  BOOLEAN        Initialized;
+
+  //
+  // Perform platform specific initialization required to enable use of the 16550 device
+  // at the location specified by PcdSerialUseMmio and PcdSerialRegisterBase.
+  //
+  Status = PlatformHookSerialPortInitialize ();
+  if (RETURN_ERROR (Status)) {
+    return Status;
+  }
+
+  //
+  // Calculate divisor for baud generator
+  //    Ref_Clk_Rate / Baud_Rate / 16
+  //
+  Divisor = PcdGet32 (PcdSerialClockRate) / (PcdGet32 (PcdSerialBaudRate) * 16);
+  if ((PcdGet32 (PcdSerialClockRate) % (PcdGet32 (PcdSerialBaudRate) * 16)) >= PcdGet32 (PcdSerialBaudRate) * 8) {
+    Divisor++;
+  }
+
+  //
+  // Get the base address of the serial port in either I/O or MMIO space
+  //
+  SerialRegisterBase = GetSerialRegisterBase ();
+  if (SerialRegisterBase ==0) {
+    return RETURN_DEVICE_ERROR;
+  }
+
+  //
+  // See if the serial port is already initialized
+  //
+  Initialized = TRUE;
+  if ((SerialPortReadRegister (SerialRegisterBase, R_UART_LCR) & 0x3F) != (PcdGet8 (PcdSerialLineControl) & 0x3F)) {
+    Initialized = FALSE;
+  }
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, (UINT8)(SerialPortReadRegister (SerialRegisterBase, R_UART_LCR) | B_UART_LCR_DLAB));
+  CurrentDivisor =  SerialPortReadRegister (SerialRegisterBase, R_UART_BAUD_HIGH) << 8;
+  CurrentDivisor |= (UINT32) SerialPortReadRegister (SerialRegisterBase, R_UART_BAUD_LOW);
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, (UINT8)(SerialPortReadRegister (SerialRegisterBase, R_UART_LCR) & ~B_UART_LCR_DLAB));
+  if (CurrentDivisor != Divisor) {
+    Initialized = FALSE;
+  }
+  if (Initialized) {
+    return RETURN_SUCCESS;
+  }
+
+  //
+  // Wait for the serial port to be ready.
+  // Verify that both the transmit FIFO and the shift register are empty.
+  //
+  while ((SerialPortReadRegister (SerialRegisterBase, R_UART_LSR) & (B_UART_LSR_TEMT | B_UART_LSR_TXRDY)) != (B_UART_LSR_TEMT | B_UART_LSR_TXRDY));
+  
+  //
+  // Configure baud rate
+  //
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, B_UART_LCR_DLAB);
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_BAUD_HIGH, (UINT8) (Divisor >> 8));
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_BAUD_LOW, (UINT8) (Divisor & 0xff));
+
+  //
+  // Clear DLAB and configure Data Bits, Parity, and Stop Bits.
+  // Strip reserved bits from PcdSerialLineControl
+  //
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, (UINT8)(PcdGet8 (PcdSerialLineControl) & 0x3F));
+
+  //
+  // Enable and reset FIFOs
+  // Strip reserved bits from PcdSerialFifoControl
+  //
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_FCR, 0x00);
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_FCR, (UINT8)(PcdGet8 (PcdSerialFifoControl) & (B_UART_FCR_FIFOE | B_UART_FCR_FIFO64)));
+
+  //
+  // Put Modem Control Register(MCR) into its reset state of 0x00.
+  //  
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_MCR, 0x00);
+
+  return RETURN_SUCCESS;
+}
+
+/**
+  Write data from buffer to serial device. 
+
+  Writes NumberOfBytes data bytes from Buffer to the serial device.  
+  The number of bytes actually written to the serial device is returned.
+  If the return value is less than NumberOfBytes, then the write operation failed.
+
+  If Buffer is NULL, then ASSERT(). 
+
+  If NumberOfBytes is zero, then return 0.
+
+  @param  Buffer           Pointer to the data buffer to be written.
+  @param  NumberOfBytes    Number of bytes to written to the serial device.
+
+  @retval 0                NumberOfBytes is 0.
+  @retval >0               The number of bytes written to the serial device.  
+                           If this value is less than NumberOfBytes, then the write operation failed.
+
+**/
+UINTN
+EFIAPI
+SerialPortWrite (
+  IN UINT8     *Buffer,
+  IN UINTN     NumberOfBytes
+  )
+{
+  UINTN  SerialRegisterBase;
+  UINTN  Result;
+  UINTN  Index;
+  UINTN  FifoSize;
+
+  if (Buffer == NULL) {
+    return 0;
+  }
+
+  SerialRegisterBase = GetSerialRegisterBase ();
+  if (SerialRegisterBase ==0) {
+    return 0;
+  }
+  
+  if (NumberOfBytes == 0) {
+    //
+    // Flush the hardware
+    //
+
+    //
+    // Wait for both the transmit FIFO and shift register empty.
+    //
+    while ((SerialPortReadRegister (SerialRegisterBase, R_UART_LSR) & (B_UART_LSR_TEMT | B_UART_LSR_TXRDY)) != (B_UART_LSR_TEMT | B_UART_LSR_TXRDY));
+
+    //
+    // Wait for the hardware flow control signal
+    //
+    while (!SerialPortWritable (SerialRegisterBase));
+    return 0;
+  }
+
+  //
+  // Compute the maximum size of the Tx FIFO
+  //
+  FifoSize = 1;
+  if ((PcdGet8 (PcdSerialFifoControl) & B_UART_FCR_FIFOE) != 0) {
+    if ((PcdGet8 (PcdSerialFifoControl) & B_UART_FCR_FIFO64) == 0) {
+      FifoSize = 16;
+    } else {
+      FifoSize = PcdGet32 (PcdSerialExtendedTxFifoSize);
+    }
+  }
+
+  Result = NumberOfBytes;
+  while (NumberOfBytes != 0) {
+    //
+    // Wait for the serial port to be ready, to make sure both the transmit FIFO
+    // and shift register empty.
+    //
+    while ((SerialPortReadRegister (SerialRegisterBase, R_UART_LSR) & B_UART_LSR_TEMT) == 0);
+
+    //
+    // Fill then entire Tx FIFO
+    //
+    for (Index = 0; Index < FifoSize && NumberOfBytes != 0; Index++, NumberOfBytes--, Buffer++) {
+      //
+      // Wait for the hardware flow control signal
+      //
+      while (!SerialPortWritable (SerialRegisterBase));
+
+      //
+      // Write byte to the transmit buffer.
+      //
+      SerialPortWriteRegister (SerialRegisterBase, R_UART_TXBUF, *Buffer);
+    }
+  }
+  return Result;
+}
+
+/**
+  Reads data from a serial device into a buffer.
+
+  @param  Buffer           Pointer to the data buffer to store the data read from the serial device.
+  @param  NumberOfBytes    Number of bytes to read from the serial device.
+
+  @retval 0                NumberOfBytes is 0.
+  @retval >0               The number of bytes read from the serial device.  
+                           If this value is less than NumberOfBytes, then the read operation failed.
+
+**/
+UINTN
+EFIAPI
+SerialPortRead (
+  OUT UINT8     *Buffer,
+  IN  UINTN     NumberOfBytes
+  )
+{
+  UINTN  SerialRegisterBase;
+  UINTN  Result;
+  UINT8  Mcr;
+
+  if (NULL == Buffer) {
+    return 0;
+  }
+
+  SerialRegisterBase = GetSerialRegisterBase ();
+  if (SerialRegisterBase ==0) {
+    return 0;
+  }
+
+  Mcr = (UINT8)(SerialPortReadRegister (SerialRegisterBase, R_UART_MCR) & ~B_UART_MCR_RTS);
+  
+  for (Result = 0; NumberOfBytes-- != 0; Result++, Buffer++) {
+    //
+    // Wait for the serial port to have some data.
+    //
+    while ((SerialPortReadRegister (SerialRegisterBase, R_UART_LSR) & B_UART_LSR_RXRDY) == 0) {
+      if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+        //
+        // Set RTS to let the peer send some data
+        //
+        SerialPortWriteRegister (SerialRegisterBase, R_UART_MCR, (UINT8)(Mcr | B_UART_MCR_RTS));
+      }
+    }
+    if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+      //
+      // Clear RTS to prevent peer from sending data
+      //
+      SerialPortWriteRegister (SerialRegisterBase, R_UART_MCR, Mcr);
+    }
+    
+    //
+    // Read byte from the receive buffer.
+    //
+    *Buffer = SerialPortReadRegister (SerialRegisterBase, R_UART_RXBUF);
+  }
+  
+  return Result;
+}
+
+
+/**
+  Polls a serial device to see if there is any data waiting to be read.
+
+  Polls aserial device to see if there is any data waiting to be read.
+  If there is data waiting to be read from the serial device, then TRUE is returned.
+  If there is no data waiting to be read from the serial device, then FALSE is returned.
+
+  @retval TRUE             Data is waiting to be read from the serial device.
+  @retval FALSE            There is no data waiting to be read from the serial device.
+
+**/
+BOOLEAN
+EFIAPI
+SerialPortPoll (
+  VOID
+  )
+{
+  UINTN  SerialRegisterBase;
+  
+  SerialRegisterBase = GetSerialRegisterBase ();
+  if (SerialRegisterBase ==0) {
+    return FALSE;
+  }
+
+  //
+  // Read the serial port status
+  //
+  if ((SerialPortReadRegister (SerialRegisterBase, R_UART_LSR) & B_UART_LSR_RXRDY) != 0) {
+    if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+      //
+      // Clear RTS to prevent peer from sending data
+      //
+      SerialPortWriteRegister (SerialRegisterBase, R_UART_MCR, (UINT8)(SerialPortReadRegister (SerialRegisterBase, R_UART_MCR) & ~B_UART_MCR_RTS));
+    }
+    return TRUE;
+  }    
+  
+  if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+    //
+    // Set RTS to let the peer send some data
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_MCR, (UINT8)(SerialPortReadRegister (SerialRegisterBase, R_UART_MCR) | B_UART_MCR_RTS));
+  }
+  
+  return FALSE;
+}
+
+/**
+  Sets the control bits on a serial device.
+
+  @param Control                Sets the bits of Control that are settable.
+
+  @retval RETURN_SUCCESS        The new control bits were set on the serial device.
+  @retval RETURN_UNSUPPORTED    The serial device does not support this operation.
+  @retval RETURN_DEVICE_ERROR   The serial device is not functioning correctly.
+
+**/
+RETURN_STATUS
+EFIAPI
+SerialPortSetControl (
+  IN UINT32 Control
+  )
+{
+  UINTN SerialRegisterBase;
+  UINT8 Mcr;
+
+  //
+  // First determine the parameter is invalid.
+  //
+  if ((Control & (~(EFI_SERIAL_REQUEST_TO_SEND | EFI_SERIAL_DATA_TERMINAL_READY |
+                    EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE))) != 0) {
+    return RETURN_UNSUPPORTED;
+  }
+
+  SerialRegisterBase = GetSerialRegisterBase ();
+  if (SerialRegisterBase ==0) {
+    return RETURN_UNSUPPORTED;
+  }
+
+  //
+  // Read the Modem Control Register.
+  //
+  Mcr = SerialPortReadRegister (SerialRegisterBase, R_UART_MCR);
+  Mcr &= (~(B_UART_MCR_DTRC | B_UART_MCR_RTS));
+
+  if ((Control & EFI_SERIAL_DATA_TERMINAL_READY) == EFI_SERIAL_DATA_TERMINAL_READY) {
+    Mcr |= B_UART_MCR_DTRC;
+  }
+
+  if ((Control & EFI_SERIAL_REQUEST_TO_SEND) == EFI_SERIAL_REQUEST_TO_SEND) {
+    Mcr |= B_UART_MCR_RTS;
+  }
+
+  //
+  // Write the Modem Control Register.
+  //
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_MCR, Mcr);
+
+  return RETURN_SUCCESS;
+}
+
+/**
+  Retrieve the status of the control bits on a serial device.
+
+  @param Control                A pointer to return the current control signals from the serial device.
+
+  @retval RETURN_SUCCESS        The control bits were read from the serial device.
+  @retval RETURN_UNSUPPORTED    The serial device does not support this operation.
+  @retval RETURN_DEVICE_ERROR   The serial device is not functioning correctly.
+
+**/
+RETURN_STATUS
+EFIAPI
+SerialPortGetControl (
+  OUT UINT32 *Control
+  )
+{
+  UINTN SerialRegisterBase;
+  UINT8 Msr;
+  UINT8 Mcr;
+  UINT8 Lsr;
+
+  SerialRegisterBase = GetSerialRegisterBase ();
+  if (SerialRegisterBase ==0) {
+    return RETURN_UNSUPPORTED;
+  }
+
+  *Control = 0;
+
+  //
+  // Read the Modem Status Register.
+  //
+  Msr = SerialPortReadRegister (SerialRegisterBase, R_UART_MSR);
+
+  if ((Msr & B_UART_MSR_CTS) == B_UART_MSR_CTS) {
+    *Control |= EFI_SERIAL_CLEAR_TO_SEND;
+  }
+
+  if ((Msr & B_UART_MSR_DSR) == B_UART_MSR_DSR) {
+    *Control |= EFI_SERIAL_DATA_SET_READY;
+  }
+
+  if ((Msr & B_UART_MSR_RI) == B_UART_MSR_RI) {
+    *Control |= EFI_SERIAL_RING_INDICATE;
+  }
+
+  if ((Msr & B_UART_MSR_DCD) == B_UART_MSR_DCD) {
+    *Control |= EFI_SERIAL_CARRIER_DETECT;
+  }
+
+  //
+  // Read the Modem Control Register.
+  //
+  Mcr = SerialPortReadRegister (SerialRegisterBase, R_UART_MCR);
+
+  if ((Mcr & B_UART_MCR_DTRC) == B_UART_MCR_DTRC) {
+    *Control |= EFI_SERIAL_DATA_TERMINAL_READY;
+  }
+
+  if ((Mcr & B_UART_MCR_RTS) == B_UART_MCR_RTS) {
+    *Control |= EFI_SERIAL_REQUEST_TO_SEND;
+  }
+
+  if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+    *Control |= EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE;
+  }
+
+  //
+  // Read the Line Status Register.
+  //
+  Lsr = SerialPortReadRegister (SerialRegisterBase, R_UART_LSR);
+
+  if ((Lsr & (B_UART_LSR_TEMT | B_UART_LSR_TXRDY)) == (B_UART_LSR_TEMT | B_UART_LSR_TXRDY)) {
+    *Control |= EFI_SERIAL_OUTPUT_BUFFER_EMPTY;
+  }
+
+  if ((Lsr & B_UART_LSR_RXRDY) == 0) {
+    *Control |= EFI_SERIAL_INPUT_BUFFER_EMPTY;
+  }
+
+  return RETURN_SUCCESS;
+}
+
+/**
+  Sets the baud rate, receive FIFO depth, transmit/receice time out, parity,
+  data bits, and stop bits on a serial device.
+
+  @param BaudRate           The requested baud rate. A BaudRate value of 0 will use the
+                            device's default interface speed.
+                            On output, the value actually set.
+  @param ReveiveFifoDepth   The requested depth of the FIFO on the receive side of the
+                            serial interface. A ReceiveFifoDepth value of 0 will use
+                            the device's default FIFO depth.
+                            On output, the value actually set.
+  @param Timeout            The requested time out for a single character in microseconds.
+                            This timeout applies to both the transmit and receive side of the
+                            interface. A Timeout value of 0 will use the device's default time
+                            out value.
+                            On output, the value actually set.
+  @param Parity             The type of parity to use on this serial device. A Parity value of
+                            DefaultParity will use the device's default parity value.
+                            On output, the value actually set.
+  @param DataBits           The number of data bits to use on the serial device. A DataBits
+                            vaule of 0 will use the device's default data bit setting.
+                            On output, the value actually set.
+  @param StopBits           The number of stop bits to use on this serial device. A StopBits
+                            value of DefaultStopBits will use the device's default number of
+                            stop bits.
+                            On output, the value actually set.
+
+  @retval RETURN_SUCCESS            The new attributes were set on the serial device.
+  @retval RETURN_UNSUPPORTED        The serial device does not support this operation.
+  @retval RETURN_INVALID_PARAMETER  One or more of the attributes has an unsupported value.
+  @retval RETURN_DEVICE_ERROR       The serial device is not functioning correctly.
+
+**/
+RETURN_STATUS
+EFIAPI
+SerialPortSetAttributes (
+  IN OUT UINT64             *BaudRate,
+  IN OUT UINT32             *ReceiveFifoDepth,
+  IN OUT UINT32             *Timeout,
+  IN OUT EFI_PARITY_TYPE    *Parity,
+  IN OUT UINT8              *DataBits,
+  IN OUT EFI_STOP_BITS_TYPE *StopBits
+  )
+{
+  UINTN     SerialRegisterBase;
+  UINT32    SerialBaudRate;
+  UINTN     Divisor;
+  UINT8     Lcr;
+  UINT8     LcrData;
+  UINT8     LcrParity;
+  UINT8     LcrStop;
+
+  SerialRegisterBase = GetSerialRegisterBase ();
+  if (SerialRegisterBase ==0) {
+    return RETURN_UNSUPPORTED;
+  }
+
+  //
+  // Check for default settings and fill in actual values.
+  //
+  if (*BaudRate == 0) {
+    *BaudRate = PcdGet32 (PcdSerialBaudRate);
+  }
+  SerialBaudRate = (UINT32) *BaudRate;
+
+  if (*DataBits == 0) {
+    LcrData = (UINT8) (PcdGet8 (PcdSerialLineControl) & 0x3);
+    *DataBits = LcrData + 5;
+  } else {
+    if ((*DataBits < 5) || (*DataBits > 8)) {
+      return RETURN_INVALID_PARAMETER;
+    }
+    //
+    // Map 5..8 to 0..3
+    //
+    LcrData = (UINT8) (*DataBits - (UINT8) 5);
+  }
+
+  if (*Parity == DefaultParity) {
+    LcrParity = (UINT8) ((PcdGet8 (PcdSerialLineControl) >> 3) & 0x7);
+    switch (LcrParity) {
+      case 0:
+        *Parity = NoParity;
+        break;
+
+      case 3:
+        *Parity = EvenParity;
+        break;
+
+      case 1:
+        *Parity = OddParity;
+        break;
+
+      case 7:
+        *Parity = SpaceParity;
+        break;
+
+      case 5:
+        *Parity = MarkParity;
+        break;
+
+      default:
+        break;
+    }
+  } else {
+    switch (*Parity) {
+      case NoParity:
+        LcrParity = 0;
+        break;
+
+      case EvenParity:
+        LcrParity = 3;
+        break;
+
+      case OddParity:
+        LcrParity = 1;
+        break;
+
+      case SpaceParity:
+        LcrParity = 7;
+        break;
+
+      case MarkParity:
+        LcrParity = 5;
+        break;
+
+      default:
+        return RETURN_INVALID_PARAMETER;
+    }
+  }
+
+  if (*StopBits == DefaultStopBits) {
+    LcrStop = (UINT8) ((PcdGet8 (PcdSerialLineControl) >> 2) & 0x1);
+    switch (LcrStop) {
+      case 0:
+        *StopBits = OneStopBit;
+        break;
+
+      case 1:
+        if (*DataBits == 5) {
+          *StopBits = OneFiveStopBits;
+        } else {
+          *StopBits = TwoStopBits;
+        }
+        break;
+
+      default:
+        break;
+    }
+  } else {
+    switch (*StopBits) {
+      case OneStopBit:
+        LcrStop = 0;
+        break;
+
+      case OneFiveStopBits:
+      case TwoStopBits:
+        LcrStop = 1;
+        break;
+
+      default:
+        return RETURN_INVALID_PARAMETER;
+    }
+  }
+
+  //
+  // Calculate divisor for baud generator
+  //    Ref_Clk_Rate / Baud_Rate / 16
+  //
+  Divisor = PcdGet32 (PcdSerialClockRate) / (SerialBaudRate * 16);
+  if ((PcdGet32 (PcdSerialClockRate) % (SerialBaudRate * 16)) >= SerialBaudRate * 8) {
+    Divisor++;
+  }
+
+  //
+  // Configure baud rate
+  //
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, B_UART_LCR_DLAB);
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_BAUD_HIGH, (UINT8) (Divisor >> 8));
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_BAUD_LOW, (UINT8) (Divisor & 0xff));
+
+  //
+  // Clear DLAB and configure Data Bits, Parity, and Stop Bits.
+  // Strip reserved bits from line control value
+  //
+  Lcr = (UINT8) ((LcrParity << 3) | (LcrStop << 2) | LcrData);
+  SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, (UINT8) (Lcr & 0x3F));
+
+  return RETURN_SUCCESS;
+}
+
diff --git a/CorebootModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.inf b/CorebootModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.inf
new file mode 100644
index 0000000000..e8b340cf91
--- /dev/null
+++ b/CorebootModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.inf
@@ -0,0 +1,48 @@
+## @file
+#  SerialPortLib instance for 16550 UART.
+#
+#  Copyright (c) 2006 - 2015, Intel Corporation. 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                      = BaseSerialPortLib16550
+  MODULE_UNI_FILE                = BaseSerialPortLib16550.uni
+  FILE_GUID                      = 9E7C00CF-355A-4d4e-BF60-0428CFF95540
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.1
+  LIBRARY_CLASS                  = SerialPortLib
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+
+[LibraryClasses]
+  PcdLib
+  IoLib
+  PlatformHookLib
+  PciLib
+
+[Sources]
+  BaseSerialPortLib16550.c
+  
+[Pcd]
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialUseMmio                 ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialUseHardwareFlowControl  ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialDetectCable             ## SOMETIMES_CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialRegisterBase            ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialBaudRate                ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialLineControl             ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialFifoControl             ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialClockRate               ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialPciDeviceInfo           ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialExtendedTxFifoSize      ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialRegisterStride          ## CONSUMES
diff --git a/CorebootModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.uni b/CorebootModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.uni
new file mode 100644
index 0000000000..0b8d7f9131
--- /dev/null
+++ b/CorebootModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.uni
@@ -0,0 +1,22 @@
+// /** @file
+// SerialPortLib instance for 16550 UART.
+//
+// SerialPortLib instance for 16550 UART.
+//
+// Copyright (c) 2006 - 2014, Intel Corporation. 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.
+//
+// **/
+
+
+#string STR_MODULE_ABSTRACT             #language en-US "SerialPortLib instance for 16550 UART"
+
+#string STR_MODULE_DESCRIPTION          #language en-US "SerialPortLib instance for 16550 UART."
+