path: root/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c

/** @file
  Serial I/O Port library functions with no library constructor/destructor

  Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
  Copyright (c) 2011 - 2012, ARM Ltd. All rights reserved.<BR>

  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#include <Library/DebugLib.h>
#include <Library/IoLib.h>
#include <Library/PcdLib.h>

#include <Drivers/PL011Uart.h>

/*

  Initialise the serial port to the specified settings.
  All unspecified settings will be set to the default values.

  @return    Always return EFI_SUCCESS or EFI_INVALID_PARAMETER.

**/
RETURN_STATUS
EFIAPI
PL011UartInitializePort (
  IN UINTN               UartBase,
  IN UINT64              BaudRate,
  IN UINT32              ReceiveFifoDepth,
  IN EFI_PARITY_TYPE     Parity,
  IN UINT8               DataBits,
  IN EFI_STOP_BITS_TYPE  StopBits
  )
{
  UINT32      LineControl;
  UINT32      Divisor;

  // The BaudRate must be passed
  if (BaudRate == 0) {
    return RETURN_INVALID_PARAMETER;
  }

  LineControl = 0;

  // The PL011 supports a buffer of either 1 or 32 chars. Therefore we can accept
  // 1 char buffer as the minimum fifo size. Because everything can be rounded down,
  // there is no maximum fifo size.
  if (ReceiveFifoDepth == 0) {
    LineControl |= PL011_UARTLCR_H_FEN;
  } else if (ReceiveFifoDepth < 32) {
    // Nothing else to do. 1 byte fifo is default.
  } else if (ReceiveFifoDepth >= 32) {
    LineControl |= PL011_UARTLCR_H_FEN;
  }

  //
  // Parity
  //
  switch (Parity) {
  case DefaultParity:
  case NoParity:
    // Nothing to do. Parity is disabled by default.
    break;
  case EvenParity:
    LineControl |= (PL011_UARTLCR_H_PEN | PL011_UARTLCR_H_EPS);
    break;
  case OddParity:
    LineControl |= PL011_UARTLCR_H_PEN;
    break;
  case MarkParity:
    LineControl |= (PL011_UARTLCR_H_PEN | PL011_UARTLCR_H_SPS | PL011_UARTLCR_H_EPS);
    break;
  case SpaceParity:
    LineControl |= (PL011_UARTLCR_H_PEN | PL011_UARTLCR_H_SPS);
    break;
  default:
    return RETURN_INVALID_PARAMETER;
  }

  //
  // Data Bits
  //
  switch (DataBits) {
  case 0:
  case 8:
    LineControl |= PL011_UARTLCR_H_WLEN_8;
    break;
  case 7:
    LineControl |= PL011_UARTLCR_H_WLEN_7;
    break;
  case 6:
    LineControl |= PL011_UARTLCR_H_WLEN_6;
    break;
  case 5:
    LineControl |= PL011_UARTLCR_H_WLEN_5;
    break;
  default:
    return RETURN_INVALID_PARAMETER;
  }

  //
  // Stop Bits
  //
  switch (StopBits) {
  case DefaultStopBits:
  case OneStopBit:
    // Nothing to do. One stop bit is enabled by default.
    break;
  case TwoStopBits:
    LineControl |= PL011_UARTLCR_H_STP2;
    break;
  case OneFiveStopBits:
    // Only 1 or 2 stops bits are supported
  default:
    return RETURN_INVALID_PARAMETER;
  }

  // Don't send the LineControl value to the PL011 yet,
  // wait until after the Baud Rate setting.
  // This ensures we do not mess up the UART settings halfway through
  // in the rare case when there is an error with the Baud Rate.

  //
  // Baud Rate
  //
  if (PcdGet32(PL011UartInteger) != 0) {
    MmioWrite32 (UartBase + UARTIBRD, PcdGet32(PL011UartInteger));
    MmioWrite32 (UartBase + UARTFBRD, PcdGet32(PL011UartFractional));
  } else {
    Divisor = (PcdGet32 (PL011UartClkInHz) * 4) / BaudRate;
    MmioWrite32 (UartBase + UARTIBRD, Divisor >> 6);
    MmioWrite32 (UartBase + UARTFBRD, Divisor & 0x3F);
  }

  // No parity, 1 stop, no fifo, 8 data bits
  MmioWrite32 (UartBase + UARTLCR_H, LineControl);

  // Clear any pending errors
  MmioWrite32 (UartBase + UARTECR, 0);

  // Enable tx, rx, and uart overall
  MmioWrite32 (UartBase + UARTCR, PL011_UARTCR_RXE | PL011_UARTCR_TXE | PL011_UARTCR_UARTEN);

  return RETURN_SUCCESS;
}

/**
  Set the serial device control bits.

  @param  UartBase                The base address of the PL011 UART.
  @param  Control                 Control bits which are to be set on the serial device.

  @retval EFI_SUCCESS             The new control bits were set on the serial device.
  @retval EFI_UNSUPPORTED         The serial device does not support this operation.
  @retval EFI_DEVICE_ERROR        The serial device is not functioning correctly.

**/
RETURN_STATUS
EFIAPI
PL011UartSetControl (
    IN UINTN                    UartBase,
    IN UINT32                   Control
  )
{
  UINT32      Bits;
  UINT32      ValidControlBits;

  ValidControlBits = (  EFI_SERIAL_REQUEST_TO_SEND
                      | EFI_SERIAL_DATA_TERMINAL_READY
  //                  | EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE       // Not implemented yet.
  //                  | EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE       // Not implemented yet.
                      | EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE
                     );

  if (Control & (~ValidControlBits)) {
    return EFI_UNSUPPORTED;
  }

  Bits = MmioRead32 (UartBase + UARTCR);

  if (Control & EFI_SERIAL_REQUEST_TO_SEND) {
    Bits |= PL011_UARTCR_RTS;
  }

  if (Control & EFI_SERIAL_DATA_TERMINAL_READY) {
    Bits |= PL011_UARTCR_DTR;
  }

  if (Control & EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE) {
    Bits |= PL011_UARTCR_LBE;
  }

  if (Control & EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE) {
    Bits |= (PL011_UARTCR_CTSEN & PL011_UARTCR_RTSEN);
  }

  MmioWrite32 (UartBase + UARTCR, Bits);

  return RETURN_SUCCESS;
}

/**
  Get the serial device control bits.

  @param  UartBase                The base address of the PL011 UART.
  @param  Control                 Control signals read from the serial device.

  @retval EFI_SUCCESS             The control bits were read from the serial device.
  @retval EFI_DEVICE_ERROR        The serial device is not functioning correctly.

**/
RETURN_STATUS
EFIAPI
PL011UartGetControl (
    IN UINTN                    UartBase,
    OUT UINT32                  *Control
  )
{
  UINT32      FlagRegister;
  UINT32      ControlRegister;


  FlagRegister = MmioRead32 (UartBase + UARTFR);
  ControlRegister = MmioRead32 (UartBase + UARTCR);

  *Control = 0;

  if ((FlagRegister & PL011_UARTFR_CTS) == PL011_UARTFR_CTS) {
    *Control |= EFI_SERIAL_CLEAR_TO_SEND;
  }

  if ((FlagRegister & PL011_UARTFR_DSR) == PL011_UARTFR_DSR) {
    *Control |= EFI_SERIAL_DATA_SET_READY;
  }

  if ((FlagRegister & PL011_UARTFR_RI) == PL011_UARTFR_RI) {
    *Control |= EFI_SERIAL_RING_INDICATE;
  }

  if ((FlagRegister & PL011_UARTFR_DCD) == PL011_UARTFR_DCD) {
    *Control |= EFI_SERIAL_CARRIER_DETECT;
  }

  if ((ControlRegister & PL011_UARTCR_RTS) == PL011_UARTCR_RTS) {
    *Control |= EFI_SERIAL_REQUEST_TO_SEND;
  }

  if ((ControlRegister & PL011_UARTCR_DTR) == PL011_UARTCR_DTR) {
    *Control |= EFI_SERIAL_DATA_TERMINAL_READY;
  }

  if ((FlagRegister & PL011_UARTFR_RXFE) == PL011_UARTFR_RXFE) {
    *Control |= EFI_SERIAL_INPUT_BUFFER_EMPTY;
  }

  if ((FlagRegister & PL011_UARTFR_TXFE) == PL011_UARTFR_TXFE) {
    *Control |= EFI_SERIAL_OUTPUT_BUFFER_EMPTY;
  }

  if ((ControlRegister & (PL011_UARTCR_CTSEN | PL011_UARTCR_RTSEN)) == (PL011_UARTCR_CTSEN | PL011_UARTCR_RTSEN)) {
    *Control |= EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE;
  }

#ifdef NEVER
  // ToDo: Implement EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE
  if ((ControlRegister & PL011_UARTCR_LBE) == PL011_UARTCR_LBE) {
    *Control |= EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE;
  }

  // ToDo: Implement EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE
  if (SoftwareLoopbackEnable) {
    *Control |= EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE;
  }
#endif

  return RETURN_SUCCESS;
}

/**
  Write data to serial device.

  @param  Buffer           Point of data buffer which need to be written.
  @param  NumberOfBytes    Number of output bytes which are cached in Buffer.

  @retval 0                Write data failed.
  @retval !0               Actual number of bytes written to serial device.

**/
UINTN
EFIAPI
PL011UartWrite (
  IN  UINTN    UartBase,
  IN UINT8     *Buffer,
  IN UINTN     NumberOfBytes
  )
{
  UINT8* CONST Final = &Buffer[NumberOfBytes];

  while (Buffer < Final) {
    // Wait until UART able to accept another char
    while ((MmioRead32 (UartBase + UARTFR) & UART_TX_FULL_FLAG_MASK));
    
    MmioWrite8 (UartBase + UARTDR, *Buffer++);
  }

  return NumberOfBytes;
}

/**
  Read data from serial device and save the data in buffer.

  @param  Buffer           Point of data buffer which need to be written.
  @param  NumberOfBytes    Number of output bytes which are cached in Buffer.

  @retval 0                Read data failed.
  @retval !0               Actual number of bytes read from serial device.

**/
UINTN
EFIAPI
PL011UartRead (
  IN  UINTN     UartBase,
  OUT UINT8     *Buffer,
  IN  UINTN     NumberOfBytes
  )
{
  UINTN   Count;

  for (Count = 0; Count < NumberOfBytes; Count++, Buffer++) {
    while ((MmioRead32 (UartBase + UARTFR) & UART_RX_EMPTY_FLAG_MASK) != 0);
    *Buffer = MmioRead8 (UartBase + UARTDR);
  }

  return NumberOfBytes;
}

/**
  Check to see if any data is available to be read from the debug device.

  @retval EFI_SUCCESS       At least one byte of data is available to be read
  @retval EFI_NOT_READY     No data is available to be read
  @retval EFI_DEVICE_ERROR  The serial device is not functioning properly

**/
BOOLEAN
EFIAPI
PL011UartPoll (
  IN  UINTN     UartBase
  )
{
  return ((MmioRead32 (UartBase + UARTFR) & UART_RX_EMPTY_FLAG_MASK) == 0);
}