ArmPkg/Library/SemiHostingSerialPortLib/SerialPortLib.c

   1 /** @file
   2   Serial I/O Port library functions with no library constructor/destructor
   3
   4   Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
   5
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7
   8 **/
   9
  10 #include <Uefi.h>
  11 #include <Library/DebugLib.h>
  12 #include <Library/SemihostLib.h>
  13 #include <Library/SerialPortLib.h>
  14
  15
  16 /*
  17
  18   Programmed hardware of Serial port.
  19
  20   @return    Always return EFI_UNSUPPORTED.
  21
  22 **/
  23 RETURN_STATUS
  24 EFIAPI
  25 SerialPortInitialize (
  26   VOID
  27   )
  28 {
  29   if (SemihostConnectionSupported ()) {
  30     return RETURN_SUCCESS;
  31   } else {
  32     return RETURN_UNSUPPORTED;
  33   }
  34 }
  35
  36 /**
  37   Write data to serial device.
  38
  39   @param  Buffer           Point of data buffer which need to be writed.
  40   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
  41
  42   @retval 0                Write data failed.
  43   @retval !0               Actual number of bytes writed to serial device.
  44
  45 **/
  46
  47 #define PRINT_BUFFER_SIZE       512
  48 #define PRINT_BUFFER_THRESHOLD  (PRINT_BUFFER_SIZE - 4)
  49
  50 UINTN
  51 EFIAPI
  52 SerialPortWrite (
  53   IN UINT8     *Buffer,
  54   IN UINTN     NumberOfBytes
  55 )
  56 {
  57   UINT8 PrintBuffer[PRINT_BUFFER_SIZE];
  58   UINTN SourceIndex      = 0;
  59   UINTN DestinationIndex = 0;
  60   UINT8 CurrentCharacter;
  61
  62   while (SourceIndex < NumberOfBytes)
  63   {
  64       CurrentCharacter = Buffer[SourceIndex++];
  65
  66       switch (CurrentCharacter)
  67       {
  68       case '\r':
  69           continue;
  70
  71       case '\n':
  72           PrintBuffer[DestinationIndex++] = ' ';
  73           // fall through
  74
  75       default:
  76           PrintBuffer[DestinationIndex++] = CurrentCharacter;
  77           break;
  78       }
  79
  80       if (DestinationIndex > PRINT_BUFFER_THRESHOLD)
  81       {
  82           PrintBuffer[DestinationIndex] = '\0';
  83           SemihostWriteString ((CHAR8 *) PrintBuffer);
  84
  85           DestinationIndex = 0;
  86       }
  87   }
  88
  89   if (DestinationIndex > 0)
  90   {
  91       PrintBuffer[DestinationIndex] = '\0';
  92       SemihostWriteString ((CHAR8 *) PrintBuffer);
  93   }
  94
  95   return NumberOfBytes;
  96 }
  97
  98
  99 /**
 100   Read data from serial device and save the datas in buffer.
 101
 102   @param  Buffer           Point of data buffer which need to be writed.
 103   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
 104
 105   @retval 0                Read data failed.
 106   @retval !0               Actual number of bytes read from serial device.
 107
 108 **/
 109 UINTN
 110 EFIAPI
 111 SerialPortRead (
 112   OUT UINT8     *Buffer,
 113   IN  UINTN     NumberOfBytes
 114 )
 115 {
 116   *Buffer = SemihostReadCharacter ();
 117   return 1;
 118 }
 119
 120
 121
 122 /**
 123   Check to see if any data is available to be read from the debug device.
 124
 125   @retval TRUE       At least one byte of data is available to be read
 126   @retval FALSE      No data is available to be read
 127
 128 **/
 129 BOOLEAN
 130 EFIAPI
 131 SerialPortPoll (
 132   VOID
 133   )
 134 {
 135   // Since SemiHosting read character is blocking always say we have a char ready?
 136   return SemihostConnectionSupported ();
 137 }
 138