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* [PATCH v4 1/2] UefiPayloadPkg: Implement a new SerialPortLib instance
@ 2022-07-26  6:34 kavya
  2022-07-26  6:34 ` [PATCH v4 2/2] UefiPayloadPkg: Allow DxeMain.inf to consume the new SerialPortLib kavya
  2022-08-22 15:49 ` [PATCH v4 1/2] UefiPayloadPkg: Implement a new SerialPortLib instance Guo Dong
  0 siblings, 2 replies; 3+ messages in thread
From: kavya @ 2022-07-26  6:34 UTC (permalink / raw)
  To: devel; +Cc: Kavya, Guo Dong, Ray Ni, Sean Rhodes, Gua Guo

Add new Serial port library instance that consumes the HOB defined
in MdeModulePkg/Include/UniversalPayload/SerialPortInfo.h to support
multiple UART's.

Cc: Guo Dong <guo.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Sean Rhodes <sean@starlabs.systems>
Cc: Gua Guo <gua.guo@intel.com>
Signed-off-by: Kavya <k.kavyax.sravanthi@intel.com>
---
 UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c   | 808 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.inf |  39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 847 insertions(+)

diff --git a/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c b/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c
new file mode 100644
index 0000000000..140ecf5f4d
--- /dev/null
+++ b/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c
@@ -0,0 +1,808 @@
+/** @file
+  UART Serial Port library functions.
+
+  Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+#include <PiDxe.h>
+#include <Base.h>
+#include <Library/PcdLib.h>
+#include <Library/IoLib.h>
+#include <Library/BaseLib.h>
+#include <Library/HobLib.h>
+#include <Library/TimerLib.h>
+#include <Library/DebugLib.h>
+#include <Protocol/SerialIo.h>
+#include <UniversalPayload/SerialPortInfo.h>
+
+//
+// 16550 UART register offsets and bitfields
+//
+#define R_UART_RXBUF         0    // LCR_DLAB = 0
+#define R_UART_TXBUF         0    // LCR_DLAB = 0
+#define R_UART_BAUD_LOW      0    // LCR_DLAB = 1
+#define R_UART_BAUD_HIGH     1    // LCR_DLAB = 1
+#define R_UART_IER           1    // LCR_DLAB = 0
+#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
+
+#define MAX_SIZE             16
+
+typedef struct {
+  UINTN                BaseAddress;
+  BOOLEAN              UseMmio;
+  UINT32               BaudRate;
+  UINT8                RegisterStride;
+} UART_INFO;
+
+UART_INFO       mUartInfo[MAX_SIZE];
+UINT8           mUartCount = 0;
+
+/**
+  Reads an 8-bit register. If UseMmio is TRUE, then the value is read from
+  MMIO space. If UseMmio is FALSE, then the value is read from I/O space. The
+  parameter Offset is added to the base address of the register.
+
+  @param  Base             The base address register of UART device.
+  @param  Offset           The offset of the register to read.
+  @param  UseMmio          Check if value has to be read from MMIO space or IO space.
+  @param  RegisterStride   Number of bytes between registers in serial device.
+
+  @return The value read from the register.
+
+**/
+UINT8
+SerialPortReadRegister (
+  UINTN    Base,
+  UINTN    Offset,
+  BOOLEAN  UseMmio,
+  UINT8    RegisterStride
+  )
+{
+  if (UseMmio) {
+    return MmioRead8 (Base + Offset * RegisterStride);
+  } else {
+    return IoRead8 (Base + Offset * RegisterStride);
+  }
+}
+
+/**
+  Writes an 8-bit register.. If UseMmio is TRUE, then the value is written to
+  MMIO space. If UseMmio is FALSE, then the value is written to I/O space. The
+  parameter Offset is added to the base address of the registers.
+
+  @param  Base             The base address register of UART device.
+  @param  Offset           The offset of the register to write.
+  @param  Value            Value to be written.
+  @param  UseMmio          Check if value has to be written to MMIO space or IO space.
+  @param  RegisterStride   Number of bytes between registers in serial device.
+
+  @return The value written to the register.
+
+**/
+UINT8
+SerialPortWriteRegister (
+  UINTN    Base,
+  UINTN    Offset,
+  UINT8    Value,
+  BOOLEAN  UseMmio,
+  UINT8    RegisterStride
+  )
+{
+  if (UseMmio) {
+    return MmioWrite8 (Base + Offset * RegisterStride, Value);
+  } else {
+    return IoWrite8 (Base + Offset * RegisterStride, Value);
+  }
+}
+
+/**
+  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
+  )
+{
+  UNIVERSAL_PAYLOAD_SERIAL_PORT_INFO  *SerialPortInfo;
+  EFI_HOB_GUID_TYPE                   *GuidHob;
+  UINTN                               SerialRegisterBase;
+  UINT8                               RegisterStride;
+  UINT32                              Divisor;
+  UINT32                              CurrentDivisor;
+  UINT32                              BaudRate;
+  BOOLEAN                             Initialized;
+  BOOLEAN                             MmioEnable;
+  UINT8                               Index;
+  UINT8                               Count;
+
+  Count = 0;
+
+  GuidHob = GetFirstGuidHob (&gUniversalPayloadSerialPortInfoGuid);
+  while (GuidHob != NULL) {
+    Count++;
+    GuidHob = GET_NEXT_HOB (GuidHob);
+    GuidHob = GetNextGuidHob (&gUniversalPayloadSerialPortInfoGuid, GuidHob);
+  }
+
+  mUartCount = Count;
+
+  Index = 0;
+  GuidHob = GetFirstGuidHob (&gUniversalPayloadSerialPortInfoGuid);
+  while (GuidHob != NULL) {
+    SerialPortInfo = (UNIVERSAL_PAYLOAD_SERIAL_PORT_INFO *)GET_GUID_HOB_DATA (GuidHob);
+    SerialRegisterBase = SerialPortInfo->RegisterBase;
+    MmioEnable         = SerialPortInfo->UseMmio;
+    BaudRate           = SerialPortInfo->BaudRate;
+    RegisterStride     = SerialPortInfo->RegisterStride;
+
+    mUartInfo[Index].BaseAddress    = SerialRegisterBase;
+    mUartInfo[Index].UseMmio        = MmioEnable;
+    mUartInfo[Index].BaudRate       = BaudRate;
+    mUartInfo[Index].RegisterStride = RegisterStride;
+    Index++;
+
+    if (SerialRegisterBase == 0) {
+      return RETURN_DEVICE_ERROR;
+    }
+
+    Divisor = PcdGet32 (PcdSerialClockRate) / (BaudRate * 16);
+    if ((PcdGet32 (PcdSerialClockRate) % (BaudRate * 16)) >= BaudRate * 8) {
+      Divisor++;
+    }
+
+    //
+    // See if the serial port is already initialized
+    //
+    Initialized = TRUE;
+    if ((SerialPortReadRegister (SerialRegisterBase, R_UART_LCR, MmioEnable, RegisterStride) & 0x3F) != (PcdGet8 (PcdSerialLineControl) & 0x3F)) {
+      Initialized = FALSE;
+    }
+
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, (UINT8)(SerialPortReadRegister (SerialRegisterBase, R_UART_LCR, MmioEnable, RegisterStride) | B_UART_LCR_DLAB), MmioEnable, RegisterStride);
+    CurrentDivisor  =  SerialPortReadRegister (SerialRegisterBase, R_UART_BAUD_HIGH, MmioEnable, RegisterStride) << 8;
+    CurrentDivisor |= (UINT32)SerialPortReadRegister (SerialRegisterBase, R_UART_BAUD_LOW, MmioEnable, RegisterStride);
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, (UINT8)(SerialPortReadRegister (SerialRegisterBase, R_UART_LCR, MmioEnable, RegisterStride) & ~B_UART_LCR_DLAB), MmioEnable, RegisterStride);
+    if (CurrentDivisor != Divisor) {
+      Initialized = FALSE;
+    }
+
+    if (Initialized) {
+      GuidHob = GET_NEXT_HOB (GuidHob);
+      GuidHob = GetNextGuidHob (&gUniversalPayloadSerialPortInfoGuid, GuidHob);
+      continue;
+    }
+
+    //
+    // Configure baud rate
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, B_UART_LCR_DLAB, MmioEnable, RegisterStride);
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_BAUD_HIGH, (UINT8)(Divisor >> 8), MmioEnable, RegisterStride);
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_BAUD_LOW, (UINT8)(Divisor & 0xff), MmioEnable, RegisterStride);
+
+    //
+    // Clear DLAB and configure Data Bits, Parity, and Stop Bits.
+    // Strip reserved bits from PcdSerialLineControl
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, (UINT8)(PcdGet8 (PcdSerialLineControl) & 0x3F), MmioEnable, RegisterStride);
+
+    //
+    // Enable and reset FIFOs
+    // Strip reserved bits from PcdSerialFifoControl
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_FCR, 0x00, MmioEnable, RegisterStride);
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_FCR, (UINT8)(PcdGet8 (PcdSerialFifoControl) & (B_UART_FCR_FIFOE | B_UART_FCR_FIFO64)), MmioEnable, RegisterStride);
+
+    //
+    // Set FIFO Polled Mode by clearing IER after setting FCR
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_IER, 0x00, MmioEnable, RegisterStride);
+
+    //
+    // Put Modem Control Register(MCR) into its reset state of 0x00.
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_MCR, 0x00, MmioEnable, RegisterStride);
+
+    GuidHob = GET_NEXT_HOB (GuidHob);
+    GuidHob = GetNextGuidHob (&gUniversalPayloadSerialPortInfoGuid, GuidHob);
+  }
+
+  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 return 0.
+
+  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                               BaseAddress;
+  BOOLEAN                             UseMmio;
+  UINTN                               BytesLeft;
+  UINTN                               Index;
+  UINTN                               FifoSize;
+  UINT8                               *DataBuffer;
+  UINT8                               Count;
+  UINT8                               Stride;
+
+  if (Buffer == NULL || NumberOfBytes == 0 || mUartCount == 0) {
+    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);
+    }
+  }
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    DataBuffer = Buffer;
+    BytesLeft  = NumberOfBytes;
+
+    while (BytesLeft != 0) {
+      //
+      // Fill the entire Tx FIFO
+      //
+      for (Index = 0; Index < FifoSize && BytesLeft != 0; Index++, BytesLeft--, DataBuffer++) {
+        //
+        // Write byte to the transmit buffer.
+        //
+        SerialPortWriteRegister (BaseAddress, R_UART_TXBUF, *DataBuffer, UseMmio, Stride);
+      }
+      MicroSecondDelay (20);
+    }
+    Count++;
+  }
+
+  return NumberOfBytes;
+}
+
+/**
+  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                               BaseAddress;
+  BOOLEAN                             UseMmio;
+  UINT8                               *DataBuffer;
+  UINTN                               BytesLeft;
+  UINTN                               Result;
+  UINT8                               Mcr;
+  UINT8                               Count;
+  UINT8                               Stride;
+
+  if (Buffer == NULL) {
+    return 0;
+  }
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    DataBuffer = Buffer;
+    BytesLeft  = NumberOfBytes;
+
+    if (BaseAddress == 0) {
+      return 0;
+    }
+
+    Mcr = (UINT8)(SerialPortReadRegister (BaseAddress, R_UART_MCR, UseMmio, Stride) & ~B_UART_MCR_RTS);
+
+    for (Result = 0; BytesLeft-- != 0; Result++, DataBuffer++) {
+      //
+      // Wait for the serial port to have some data.
+      //
+      while ((SerialPortReadRegister (BaseAddress, R_UART_LSR, UseMmio, Stride) & B_UART_LSR_RXRDY) == 0) {
+        if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+          //
+          // Set RTS to let the peer send some data
+          //
+          SerialPortWriteRegister (BaseAddress, R_UART_MCR, (UINT8)(Mcr | B_UART_MCR_RTS), UseMmio, Stride);
+        }
+      }
+
+      if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+        //
+        // Clear RTS to prevent peer from sending data
+        //
+        SerialPortWriteRegister (BaseAddress, R_UART_MCR, Mcr, UseMmio, Stride);
+      }
+
+      //
+      // Read byte from the receive buffer.
+      //
+      *DataBuffer = SerialPortReadRegister (BaseAddress, R_UART_RXBUF, UseMmio, Stride);
+    }
+    Count++;
+  }
+
+  return Result;
+}
+
+/**
+  Polls a serial device to see if there is any data waiting to be read.
+
+  Polls a serial 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                               BaseAddress;
+  BOOLEAN                             UseMmio;
+  UINT8                               Stride;
+  UINT8                               Count;
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    if (BaseAddress == 0) {
+      return FALSE;
+    }
+
+    //
+    // Read the serial port status
+    //
+    if ((SerialPortReadRegister (BaseAddress, R_UART_LSR, UseMmio, Stride) & B_UART_LSR_RXRDY) != 0) {
+      if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+        //
+        // Clear RTS to prevent peer from sending data
+        //
+        SerialPortWriteRegister (BaseAddress, R_UART_MCR, (UINT8)(SerialPortReadRegister (BaseAddress, R_UART_MCR, UseMmio, Stride) & ~B_UART_MCR_RTS), UseMmio, Stride);
+      }
+      return TRUE;
+    }
+
+    if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+      //
+      // Set RTS to let the peer send some data
+      //
+      SerialPortWriteRegister (BaseAddress, R_UART_MCR, (UINT8)(SerialPortReadRegister (BaseAddress, R_UART_MCR, UseMmio, Stride) | B_UART_MCR_RTS), UseMmio, Stride);
+    }
+    Count++;
+  }
+  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                      BaseAddress;
+  BOOLEAN                    UseMmio;
+  UINT8                      Mcr;
+  UINT8                      Count;
+  UINT8                      Stride;
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    if (BaseAddress == 0) {
+      return RETURN_UNSUPPORTED;
+    }
+
+    //
+    // 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;
+    }
+
+    //
+    // Read the Modem Control Register.
+    //
+    Mcr  = SerialPortReadRegister (BaseAddress, R_UART_MCR, UseMmio, Stride);
+    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 (BaseAddress, R_UART_MCR, Mcr, UseMmio, Stride);
+    Count++;
+  }
+
+  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                               BaseAddress;
+  BOOLEAN                             UseMmio;
+  UINT8                               Msr;
+  UINT8                               Mcr;
+  UINT8                               Lsr;
+  UINT8                               Count;
+  UINT8                               Stride;
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    if (BaseAddress == 0) {
+      return RETURN_UNSUPPORTED;
+    }
+
+    *Control = 0;
+
+    //
+    // Read the Modem Status Register.
+    //
+    Msr = SerialPortReadRegister (BaseAddress, R_UART_MSR, UseMmio, Stride);
+
+    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 (BaseAddress, R_UART_MCR, UseMmio, Stride);
+
+    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 (BaseAddress, R_UART_LSR, UseMmio, Stride);
+
+    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;
+    }
+    Count++;
+  }
+
+  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                               BaseAddress;
+  BOOLEAN                             UseMmio;
+  UINT32                              SerialBaudRate;
+  UINTN                               Divisor;
+  UINT8                               Lcr;
+  UINT8                               LcrData;
+  UINT8                               LcrParity;
+  UINT8                               LcrStop;
+  UINT8                               Count;
+  UINT8                               Stride;
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    if (BaseAddress == 0) {
+      return RETURN_UNSUPPORTED;
+    }
+
+    //
+    // Check for default settings and fill in actual values.
+    //
+    if (*BaudRate == 0) {
+      *BaudRate = mUartInfo[Count].BaudRate;
+    }
+
+    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 (BaseAddress, R_UART_LCR, B_UART_LCR_DLAB, UseMmio, Stride);
+    SerialPortWriteRegister (BaseAddress, R_UART_BAUD_HIGH, (UINT8)(Divisor >> 8), UseMmio, Stride);
+    SerialPortWriteRegister (BaseAddress, R_UART_BAUD_LOW, (UINT8)(Divisor & 0xff), UseMmio, Stride);
+
+    //
+    // 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 (BaseAddress, R_UART_LCR, (UINT8)(Lcr & 0x3F), UseMmio, Stride);
+    Count++;
+  }
+
+  return RETURN_SUCCESS;
+}
diff --git a/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.inf b/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.inf
new file mode 100644
index 0000000000..ac857d3eea
--- /dev/null
+++ b/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.inf
@@ -0,0 +1,39 @@
+## @file
+#  SerialPortLib instance for UART information retrieved from bootloader.
+#
+#  Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = BaseSerialPortLibHob
+  FILE_GUID                      = d8d22930-e8ec-469f-8184-5a069149b2ff
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = SerialPortLib
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+
+[LibraryClasses]
+  PcdLib
+  IoLib
+  HobLib
+  TimerLib
+
+[Sources]
+  BaseSerialPortLibHob.c
+
+[Pcd]
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialLineControl
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialFifoControl
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialClockRate
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialExtendedTxFifoSize
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialUseHardwareFlowControl
+
+[Guids]
+  gUniversalPayloadSerialPortInfoGuid
-- 
2.30.2.windows.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* [PATCH v4 2/2] UefiPayloadPkg: Allow DxeMain.inf to consume the new SerialPortLib
  2022-07-26  6:34 [PATCH v4 1/2] UefiPayloadPkg: Implement a new SerialPortLib instance kavya
@ 2022-07-26  6:34 ` kavya
  2022-08-22 15:49 ` [PATCH v4 1/2] UefiPayloadPkg: Implement a new SerialPortLib instance Guo Dong
  1 sibling, 0 replies; 3+ messages in thread
From: kavya @ 2022-07-26  6:34 UTC (permalink / raw)
  To: devel; +Cc: Kavya, Guo Dong, Ray Ni, Sean Rhodes, Gua Guo

Let DxeMain.inf consume new SerialPortLib to support multiple
channel debug message on early DXE.

Cc: Guo Dong <guo.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Sean Rhodes <sean@starlabs.systems>
Cc: Gua Guo <gua.guo@intel.com>
Signed-off-by: Kavya <k.kavyax.sravanthi@intel.com>
---
 UefiPayloadPkg/UefiPayloadPkg.dsc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/UefiPayloadPkg/UefiPayloadPkg.dsc b/UefiPayloadPkg/UefiPayloadPkg.dsc
index 862d440b16..de3684fa22 100644
--- a/UefiPayloadPkg/UefiPayloadPkg.dsc
+++ b/UefiPayloadPkg/UefiPayloadPkg.dsc
@@ -590,6 +590,8 @@
   #
   MdeModulePkg/Core/Dxe/DxeMain.inf {
     <LibraryClasses>
+      DebugLib|MdePkg/Library/BaseDebugLibSerialPort/BaseDebugLibSerialPort.inf
+      SerialPortLib|UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.inf
       NULL|MdeModulePkg/Library/LzmaCustomDecompressLib/LzmaCustomDecompressLib.inf
   }
 
-- 
2.30.2.windows.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH v4 1/2] UefiPayloadPkg: Implement a new SerialPortLib instance
  2022-07-26  6:34 [PATCH v4 1/2] UefiPayloadPkg: Implement a new SerialPortLib instance kavya
  2022-07-26  6:34 ` [PATCH v4 2/2] UefiPayloadPkg: Allow DxeMain.inf to consume the new SerialPortLib kavya
@ 2022-08-22 15:49 ` Guo Dong
  1 sibling, 0 replies; 3+ messages in thread
From: Guo Dong @ 2022-08-22 15:49 UTC (permalink / raw)
  To: Sravanthi, K KavyaX, devel@edk2.groups.io; +Cc: Ni, Ray, Rhodes, Sean, Guo, Gua


In SerialPortInitialize(), these code could be removed.

+  Count = 0;
+
+  GuidHob = GetFirstGuidHob (&gUniversalPayloadSerialPortInfoGuid);
+  while (GuidHob != NULL) {
+    Count++;
+    GuidHob = GET_NEXT_HOB (GuidHob);
+    GuidHob = GetNextGuidHob (&gUniversalPayloadSerialPortInfoGuid, GuidHob);
+  }
+
+  mUartCount = Count;
+
+  Index = 0;

And change Index to mUartCount in below code.
Since multiple serial port support and SerialRegisterBase check, one serial port failure should not impact others.
So SerialRegisterBase check failure should continue checking other serial port. And move this check before setting mUartInfo.

+  GuidHob = GetFirstGuidHob (&gUniversalPayloadSerialPortInfoGuid);
+  while (GuidHob != NULL) {
+    SerialPortInfo = (UNIVERSAL_PAYLOAD_SERIAL_PORT_INFO *)GET_GUID_HOB_DATA (GuidHob);
+    SerialRegisterBase = SerialPortInfo->RegisterBase;
+    MmioEnable         = SerialPortInfo->UseMmio;
+    BaudRate           = SerialPortInfo->BaudRate;
+    RegisterStride     = SerialPortInfo->RegisterStride;
+
+    mUartInfo[Index].BaseAddress    = SerialRegisterBase;
+    mUartInfo[Index].UseMmio        = MmioEnable;
+    mUartInfo[Index].BaudRate       = BaudRate;
+    mUartInfo[Index].RegisterStride = RegisterStride;
+    Index++;
+
+    if (SerialRegisterBase == 0) {
+      return RETURN_DEVICE_ERROR;
+    }

Thanks,
Guo

-----Original Message-----
From: Sravanthi, K KavyaX <k.kavyax.sravanthi@intel.com> 
Sent: Monday, July 25, 2022 11:34 PM
To: devel@edk2.groups.io
Cc: Sravanthi, K KavyaX <k.kavyax.sravanthi@intel.com>; Dong, Guo <guo.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; Rhodes, Sean <sean@starlabs.systems>; Guo, Gua <gua.guo@intel.com>
Subject: [PATCH v4 1/2] UefiPayloadPkg: Implement a new SerialPortLib instance

Add new Serial port library instance that consumes the HOB defined in MdeModulePkg/Include/UniversalPayload/SerialPortInfo.h to support multiple UART's.

Cc: Guo Dong <guo.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Sean Rhodes <sean@starlabs.systems>
Cc: Gua Guo <gua.guo@intel.com>
Signed-off-by: Kavya <k.kavyax.sravanthi@intel.com>
---
 UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c   | 808 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.inf |  39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 847 insertions(+)

diff --git a/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c b/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c
new file mode 100644
index 0000000000..140ecf5f4d
--- /dev/null
+++ b/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c
@@ -0,0 +1,808 @@
+/** @file
+  UART Serial Port library functions.
+
+  Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+#include <PiDxe.h>
+#include <Base.h>
+#include <Library/PcdLib.h>
+#include <Library/IoLib.h>
+#include <Library/BaseLib.h>
+#include <Library/HobLib.h>
+#include <Library/TimerLib.h>
+#include <Library/DebugLib.h>
+#include <Protocol/SerialIo.h>
+#include <UniversalPayload/SerialPortInfo.h>
+
+//
+// 16550 UART register offsets and bitfields //
+#define R_UART_RXBUF         0    // LCR_DLAB = 0
+#define R_UART_TXBUF         0    // LCR_DLAB = 0
+#define R_UART_BAUD_LOW      0    // LCR_DLAB = 1
+#define R_UART_BAUD_HIGH     1    // LCR_DLAB = 1
+#define R_UART_IER           1    // LCR_DLAB = 0
+#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
+
+#define MAX_SIZE             16
+
+typedef struct {
+  UINTN                BaseAddress;
+  BOOLEAN              UseMmio;
+  UINT32               BaudRate;
+  UINT8                RegisterStride;
+} UART_INFO;
+
+UART_INFO       mUartInfo[MAX_SIZE];
+UINT8           mUartCount = 0;
+
+/**
+  Reads an 8-bit register. If UseMmio is TRUE, then the value is read 
+from
+  MMIO space. If UseMmio is FALSE, then the value is read from I/O 
+space. The
+  parameter Offset is added to the base address of the register.
+
+  @param  Base             The base address register of UART device.
+  @param  Offset           The offset of the register to read.
+  @param  UseMmio          Check if value has to be read from MMIO space or IO space.
+  @param  RegisterStride   Number of bytes between registers in serial device.
+
+  @return The value read from the register.
+
+**/
+UINT8
+SerialPortReadRegister (
+  UINTN    Base,
+  UINTN    Offset,
+  BOOLEAN  UseMmio,
+  UINT8    RegisterStride
+  )
+{
+  if (UseMmio) {
+    return MmioRead8 (Base + Offset * RegisterStride);
+  } else {
+    return IoRead8 (Base + Offset * RegisterStride);
+  }
+}
+
+/**
+  Writes an 8-bit register.. If UseMmio is TRUE, then the value is 
+written to
+  MMIO space. If UseMmio is FALSE, then the value is written to I/O 
+space. The
+  parameter Offset is added to the base address of the registers.
+
+  @param  Base             The base address register of UART device.
+  @param  Offset           The offset of the register to write.
+  @param  Value            Value to be written.
+  @param  UseMmio          Check if value has to be written to MMIO space or IO space.
+  @param  RegisterStride   Number of bytes between registers in serial device.
+
+  @return The value written to the register.
+
+**/
+UINT8
+SerialPortWriteRegister (
+  UINTN    Base,
+  UINTN    Offset,
+  UINT8    Value,
+  BOOLEAN  UseMmio,
+  UINT8    RegisterStride
+  )
+{
+  if (UseMmio) {
+    return MmioWrite8 (Base + Offset * RegisterStride, Value);
+  } else {
+    return IoWrite8 (Base + Offset * RegisterStride, Value);
+  }
+}
+
+/**
+  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
+  )
+{
+  UNIVERSAL_PAYLOAD_SERIAL_PORT_INFO  *SerialPortInfo;
+  EFI_HOB_GUID_TYPE                   *GuidHob;
+  UINTN                               SerialRegisterBase;
+  UINT8                               RegisterStride;
+  UINT32                              Divisor;
+  UINT32                              CurrentDivisor;
+  UINT32                              BaudRate;
+  BOOLEAN                             Initialized;
+  BOOLEAN                             MmioEnable;
+  UINT8                               Index;
+  UINT8                               Count;
+
+  Count = 0;
+
+  GuidHob = GetFirstGuidHob (&gUniversalPayloadSerialPortInfoGuid);
+  while (GuidHob != NULL) {
+    Count++;
+    GuidHob = GET_NEXT_HOB (GuidHob);
+    GuidHob = GetNextGuidHob (&gUniversalPayloadSerialPortInfoGuid, 
+ GuidHob);  }
+
+  mUartCount = Count;
+
+  Index = 0;
+  GuidHob = GetFirstGuidHob (&gUniversalPayloadSerialPortInfoGuid);
+  while (GuidHob != NULL) {
+    SerialPortInfo = (UNIVERSAL_PAYLOAD_SERIAL_PORT_INFO *)GET_GUID_HOB_DATA (GuidHob);
+    SerialRegisterBase = SerialPortInfo->RegisterBase;
+    MmioEnable         = SerialPortInfo->UseMmio;
+    BaudRate           = SerialPortInfo->BaudRate;
+    RegisterStride     = SerialPortInfo->RegisterStride;
+
+    mUartInfo[Index].BaseAddress    = SerialRegisterBase;
+    mUartInfo[Index].UseMmio        = MmioEnable;
+    mUartInfo[Index].BaudRate       = BaudRate;
+    mUartInfo[Index].RegisterStride = RegisterStride;
+    Index++;
+
+    if (SerialRegisterBase == 0) {
+      return RETURN_DEVICE_ERROR;
+    }
+
+    Divisor = PcdGet32 (PcdSerialClockRate) / (BaudRate * 16);
+    if ((PcdGet32 (PcdSerialClockRate) % (BaudRate * 16)) >= BaudRate * 8) {
+      Divisor++;
+    }
+
+    //
+    // See if the serial port is already initialized
+    //
+    Initialized = TRUE;
+    if ((SerialPortReadRegister (SerialRegisterBase, R_UART_LCR, MmioEnable, RegisterStride) & 0x3F) != (PcdGet8 (PcdSerialLineControl) & 0x3F)) {
+      Initialized = FALSE;
+    }
+
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, (UINT8)(SerialPortReadRegister (SerialRegisterBase, R_UART_LCR, MmioEnable, RegisterStride) | B_UART_LCR_DLAB), MmioEnable, RegisterStride);
+    CurrentDivisor  =  SerialPortReadRegister (SerialRegisterBase, R_UART_BAUD_HIGH, MmioEnable, RegisterStride) << 8;
+    CurrentDivisor |= (UINT32)SerialPortReadRegister (SerialRegisterBase, R_UART_BAUD_LOW, MmioEnable, RegisterStride);
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, (UINT8)(SerialPortReadRegister (SerialRegisterBase, R_UART_LCR, MmioEnable, RegisterStride) & ~B_UART_LCR_DLAB), MmioEnable, RegisterStride);
+    if (CurrentDivisor != Divisor) {
+      Initialized = FALSE;
+    }
+
+    if (Initialized) {
+      GuidHob = GET_NEXT_HOB (GuidHob);
+      GuidHob = GetNextGuidHob (&gUniversalPayloadSerialPortInfoGuid, GuidHob);
+      continue;
+    }
+
+    //
+    // Configure baud rate
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, B_UART_LCR_DLAB, MmioEnable, RegisterStride);
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_BAUD_HIGH, (UINT8)(Divisor >> 8), MmioEnable, RegisterStride);
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_BAUD_LOW, 
+ (UINT8)(Divisor & 0xff), MmioEnable, RegisterStride);
+
+    //
+    // Clear DLAB and configure Data Bits, Parity, and Stop Bits.
+    // Strip reserved bits from PcdSerialLineControl
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_LCR, 
+ (UINT8)(PcdGet8 (PcdSerialLineControl) & 0x3F), MmioEnable, 
+ RegisterStride);
+
+    //
+    // Enable and reset FIFOs
+    // Strip reserved bits from PcdSerialFifoControl
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_FCR, 0x00, MmioEnable, RegisterStride);
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_FCR, 
+ (UINT8)(PcdGet8 (PcdSerialFifoControl) & (B_UART_FCR_FIFOE | 
+ B_UART_FCR_FIFO64)), MmioEnable, RegisterStride);
+
+    //
+    // Set FIFO Polled Mode by clearing IER after setting FCR
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_IER, 0x00, 
+ MmioEnable, RegisterStride);
+
+    //
+    // Put Modem Control Register(MCR) into its reset state of 0x00.
+    //
+    SerialPortWriteRegister (SerialRegisterBase, R_UART_MCR, 0x00, 
+ MmioEnable, RegisterStride);
+
+    GuidHob = GET_NEXT_HOB (GuidHob);
+    GuidHob = GetNextGuidHob (&gUniversalPayloadSerialPortInfoGuid, 
+ GuidHob);  }
+
+  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 return 0.
+
+  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                               BaseAddress;
+  BOOLEAN                             UseMmio;
+  UINTN                               BytesLeft;
+  UINTN                               Index;
+  UINTN                               FifoSize;
+  UINT8                               *DataBuffer;
+  UINT8                               Count;
+  UINT8                               Stride;
+
+  if (Buffer == NULL || NumberOfBytes == 0 || mUartCount == 0) {
+    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);
+    }
+  }
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    DataBuffer = Buffer;
+    BytesLeft  = NumberOfBytes;
+
+    while (BytesLeft != 0) {
+      //
+      // Fill the entire Tx FIFO
+      //
+      for (Index = 0; Index < FifoSize && BytesLeft != 0; Index++, BytesLeft--, DataBuffer++) {
+        //
+        // Write byte to the transmit buffer.
+        //
+        SerialPortWriteRegister (BaseAddress, R_UART_TXBUF, *DataBuffer, UseMmio, Stride);
+      }
+      MicroSecondDelay (20);
+    }
+    Count++;
+  }
+
+  return NumberOfBytes;
+}
+
+/**
+  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                               BaseAddress;
+  BOOLEAN                             UseMmio;
+  UINT8                               *DataBuffer;
+  UINTN                               BytesLeft;
+  UINTN                               Result;
+  UINT8                               Mcr;
+  UINT8                               Count;
+  UINT8                               Stride;
+
+  if (Buffer == NULL) {
+    return 0;
+  }
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    DataBuffer = Buffer;
+    BytesLeft  = NumberOfBytes;
+
+    if (BaseAddress == 0) {
+      return 0;
+    }
+
+    Mcr = (UINT8)(SerialPortReadRegister (BaseAddress, R_UART_MCR, 
+ UseMmio, Stride) & ~B_UART_MCR_RTS);
+
+    for (Result = 0; BytesLeft-- != 0; Result++, DataBuffer++) {
+      //
+      // Wait for the serial port to have some data.
+      //
+      while ((SerialPortReadRegister (BaseAddress, R_UART_LSR, UseMmio, Stride) & B_UART_LSR_RXRDY) == 0) {
+        if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+          //
+          // Set RTS to let the peer send some data
+          //
+          SerialPortWriteRegister (BaseAddress, R_UART_MCR, (UINT8)(Mcr | B_UART_MCR_RTS), UseMmio, Stride);
+        }
+      }
+
+      if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+        //
+        // Clear RTS to prevent peer from sending data
+        //
+        SerialPortWriteRegister (BaseAddress, R_UART_MCR, Mcr, UseMmio, Stride);
+      }
+
+      //
+      // Read byte from the receive buffer.
+      //
+      *DataBuffer = SerialPortReadRegister (BaseAddress, R_UART_RXBUF, UseMmio, Stride);
+    }
+    Count++;
+  }
+
+  return Result;
+}
+
+/**
+  Polls a serial device to see if there is any data waiting to be read.
+
+  Polls a serial 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                               BaseAddress;
+  BOOLEAN                             UseMmio;
+  UINT8                               Stride;
+  UINT8                               Count;
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    if (BaseAddress == 0) {
+      return FALSE;
+    }
+
+    //
+    // Read the serial port status
+    //
+    if ((SerialPortReadRegister (BaseAddress, R_UART_LSR, UseMmio, Stride) & B_UART_LSR_RXRDY) != 0) {
+      if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+        //
+        // Clear RTS to prevent peer from sending data
+        //
+        SerialPortWriteRegister (BaseAddress, R_UART_MCR, (UINT8)(SerialPortReadRegister (BaseAddress, R_UART_MCR, UseMmio, Stride) & ~B_UART_MCR_RTS), UseMmio, Stride);
+      }
+      return TRUE;
+    }
+
+    if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+      //
+      // Set RTS to let the peer send some data
+      //
+      SerialPortWriteRegister (BaseAddress, R_UART_MCR, (UINT8)(SerialPortReadRegister (BaseAddress, R_UART_MCR, UseMmio, Stride) | B_UART_MCR_RTS), UseMmio, Stride);
+    }
+    Count++;
+  }
+  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                      BaseAddress;
+  BOOLEAN                    UseMmio;
+  UINT8                      Mcr;
+  UINT8                      Count;
+  UINT8                      Stride;
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    if (BaseAddress == 0) {
+      return RETURN_UNSUPPORTED;
+    }
+
+    //
+    // 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;
+    }
+
+    //
+    // Read the Modem Control Register.
+    //
+    Mcr  = SerialPortReadRegister (BaseAddress, R_UART_MCR, UseMmio, Stride);
+    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 (BaseAddress, R_UART_MCR, Mcr, UseMmio, Stride);
+    Count++;
+  }
+
+  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                               BaseAddress;
+  BOOLEAN                             UseMmio;
+  UINT8                               Msr;
+  UINT8                               Mcr;
+  UINT8                               Lsr;
+  UINT8                               Count;
+  UINT8                               Stride;
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    if (BaseAddress == 0) {
+      return RETURN_UNSUPPORTED;
+    }
+
+    *Control = 0;
+
+    //
+    // Read the Modem Status Register.
+    //
+    Msr = SerialPortReadRegister (BaseAddress, R_UART_MSR, UseMmio, 
+ Stride);
+
+    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 (BaseAddress, R_UART_MCR, UseMmio, 
+ Stride);
+
+    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 (BaseAddress, R_UART_LSR, UseMmio, 
+ Stride);
+
+    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;
+    }
+    Count++;
+  }
+
+  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                               BaseAddress;
+  BOOLEAN                             UseMmio;
+  UINT32                              SerialBaudRate;
+  UINTN                               Divisor;
+  UINT8                               Lcr;
+  UINT8                               LcrData;
+  UINT8                               LcrParity;
+  UINT8                               LcrStop;
+  UINT8                               Count;
+  UINT8                               Stride;
+
+  Count = 0;
+  while (Count < mUartCount) {
+    BaseAddress = mUartInfo[Count].BaseAddress;
+    UseMmio     = mUartInfo[Count].UseMmio;
+    Stride      = mUartInfo[Count].RegisterStride;
+
+    if (BaseAddress == 0) {
+      return RETURN_UNSUPPORTED;
+    }
+
+    //
+    // Check for default settings and fill in actual values.
+    //
+    if (*BaudRate == 0) {
+      *BaudRate = mUartInfo[Count].BaudRate;
+    }
+
+    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 (BaseAddress, R_UART_LCR, B_UART_LCR_DLAB, UseMmio, Stride);
+    SerialPortWriteRegister (BaseAddress, R_UART_BAUD_HIGH, (UINT8)(Divisor >> 8), UseMmio, Stride);
+    SerialPortWriteRegister (BaseAddress, R_UART_BAUD_LOW, 
+ (UINT8)(Divisor & 0xff), UseMmio, Stride);
+
+    //
+    // 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 (BaseAddress, R_UART_LCR, (UINT8)(Lcr & 0x3F), UseMmio, Stride);
+    Count++;
+  }
+
+  return RETURN_SUCCESS;
+}
diff --git a/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.inf b/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.inf
new file mode 100644
index 0000000000..ac857d3eea
--- /dev/null
+++ b/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.i
+++ nf
@@ -0,0 +1,39 @@
+## @file
+#  SerialPortLib instance for UART information retrieved from bootloader.
+#
+#  Copyright (c) 2022, Intel Corporation. All rights reserved.<BR> # #  
+SPDX-License-Identifier: BSD-2-Clause-Patent # ##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = BaseSerialPortLibHob
+  FILE_GUID                      = d8d22930-e8ec-469f-8184-5a069149b2ff
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = SerialPortLib
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+
+[LibraryClasses]
+  PcdLib
+  IoLib
+  HobLib
+  TimerLib
+
+[Sources]
+  BaseSerialPortLibHob.c
+
+[Pcd]
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialLineControl
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialFifoControl
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialClockRate
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialExtendedTxFifoSize
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialUseHardwareFlowControl
+
+[Guids]
+  gUniversalPayloadSerialPortInfoGuid
--
2.30.2.windows.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

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Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
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2022-08-22 15:49 ` [PATCH v4 1/2] UefiPayloadPkg: Implement a new SerialPortLib instance Guo Dong

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