Library/FdtPL011SerialPortLib/EarlyFdtPL011SerialPortLib.c

/** @file
  Serial I/O Port library functions with base address discovered from FDT

  Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
  Copyright (c) 2012 - 2013, ARM Ltd. All rights reserved.<BR>
  Copyright (c) 2014, Linaro Ltd. All rights reserved.<BR>
  Copyright (c) 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.

**/

#include <Base.h>

#include <Library/PcdLib.h>
#include <Library/SerialPortLib.h>
#include <libfdt.h>

#include <Drivers/PL011Uart.h>

RETURN_STATUS
EFIAPI
SerialPortInitialize (
  VOID
  )
{
  //
  // This SerialPortInitialize() function is completely empty, for a number of
  // reasons:
  // - if we are executing from flash, it is hard to keep state (i.e., store the
  //   discovered base address in a global), and the most robust way to deal
  //   with this is to discover the base address at every Write ();
  // - calls to the Write() function in this module may be issued before this
  //   initialization function is called: this is not a problem when the base
  //   address of the UART is hardcoded, and only the baud rate may be wrong,
  //   but if we don't know the base address yet, we may be poking into memory
  //   that does not tolerate being poked into;
  // - SEC and PEI phases produce debug output only, so with debug disabled, no
  //   initialization (or device tree parsing) is performed at all.
  //
  // Note that this means that on *every* Write () call, the device tree will be
  // parsed and the UART re-initialized. However, this is a small price to pay
  // for having serial debug output on a UART with no fixed base address.
  //
  return RETURN_SUCCESS;
}

STATIC
UINT64
SerialPortGetBaseAddress (
  VOID
  )
{
  UINT64              BaudRate;
  UINT32              ReceiveFifoDepth;
  EFI_PARITY_TYPE     Parity;
  UINT8               DataBits;
  EFI_STOP_BITS_TYPE  StopBits;
  VOID                *DeviceTreeBase;
  INT32               Node, Prev;
  INT32               Len;
  CONST CHAR8         *Compatible;
  CONST CHAR8         *CompatibleItem;
  CONST UINT64        *RegProperty;
  UINTN               UartBase;
  RETURN_STATUS       Status;

  DeviceTreeBase = (VOID *)(UINTN)FixedPcdGet64 (PcdDeviceTreeInitialBaseAddress);

  if ((DeviceTreeBase == NULL) || (fdt_check_header (DeviceTreeBase) != 0)) {
    return 0;
  }

  //
  // Enumerate all FDT nodes looking for a PL011 and capture its base address
  //
  for (Prev = 0;; Prev = Node) {
    Node = fdt_next_node (DeviceTreeBase, Prev, NULL);
    if (Node < 0) {
      break;
    }

    Compatible = fdt_getprop (DeviceTreeBase, Node, "compatible", &Len);
    if (Compatible == NULL) {
      continue;
    }

    //
    // Iterate over the NULL-separated items in the compatible string
    //
    for (CompatibleItem = Compatible; CompatibleItem < Compatible + Len;
      CompatibleItem += 1 + AsciiStrLen (CompatibleItem)) {

      if (AsciiStrCmp (CompatibleItem, "arm,pl011") == 0) {
        RegProperty = fdt_getprop (DeviceTreeBase, Node, "reg", &Len);
        if (Len != 16) {
          return 0;
        }
        UartBase = (UINTN)fdt64_to_cpu (ReadUnaligned64 (RegProperty));

        BaudRate = (UINTN)FixedPcdGet64 (PcdUartDefaultBaudRate);
        ReceiveFifoDepth = 0; // Use the default value for Fifo depth
        Parity = (EFI_PARITY_TYPE)FixedPcdGet8 (PcdUartDefaultParity);
        DataBits = FixedPcdGet8 (PcdUartDefaultDataBits);
        StopBits = (EFI_STOP_BITS_TYPE) FixedPcdGet8 (PcdUartDefaultStopBits);

        Status = PL011UartInitializePort (
                   UartBase,
                   &BaudRate, &ReceiveFifoDepth, &Parity, &DataBits, &StopBits);
        if (!EFI_ERROR (Status)) {
          return UartBase;
        }
      }
    }
  }
  return 0;
}

/**
  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
SerialPortWrite (
  IN UINT8     *Buffer,
  IN UINTN     NumberOfBytes
  )
{
  UINT64 SerialRegisterBase;

  SerialRegisterBase = SerialPortGetBaseAddress ();
  if (SerialRegisterBase != 0) {
    return PL011UartWrite ((UINTN)SerialRegisterBase, Buffer, NumberOfBytes);
  }
  return 0;
}

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

  @param  Buffer           Point of data buffer which need to be written.
  @param  NumberOfBytes    Size of Buffer[].

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

**/
UINTN
EFIAPI
SerialPortRead (
  OUT UINT8     *Buffer,
  IN  UINTN     NumberOfBytes
)
{
  return 0;
}

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

  @retval TRUE       At least one byte of data is available to be read
  @retval FALSE      No data is available to be read

**/
BOOLEAN
EFIAPI
SerialPortPoll (
  VOID
  )
{
  return FALSE;
}

/**
  Sets the control bits on a serial device.

  @param[in] 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
  )
{
  return RETURN_UNSUPPORTED;
}

/**
  Retrieve the status of the control bits on a serial device.

  @param[out] 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
  )
{
  return RETURN_UNSUPPORTED;
}

/**
  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
  )
{
  return RETURN_UNSUPPORTED;
}