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   Copyright (c) 2021, Arm Limited. All rights reserved.<BR>
   6
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8
   9 **/
  10
  11 #include <Uefi.h>
  12 #include <Library/DebugLib.h>
  13 #include <Library/SemihostLib.h>
  14 #include <Library/SerialPortLib.h>
  15
  16
  17 /*
  18
  19   Programmed hardware of Serial port.
  20
  21   @return    Always return EFI_UNSUPPORTED.
  22
  23 **/
  24 RETURN_STATUS
  25 EFIAPI
  26 SerialPortInitialize (
  27   VOID
  28   )
  29 {
  30   if (SemihostConnectionSupported ()) {
  31     return RETURN_SUCCESS;
  32   } else {
  33     return RETURN_UNSUPPORTED;
  34   }
  35 }
  36
  37 /**
  38   Write data to serial device.
  39
  40   @param  Buffer           Point of data buffer which need to be writed.
  41   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
  42
  43   @retval 0                Write data failed.
  44   @retval !0               Actual number of bytes writed to serial device.
  45
  46 **/
  47
  48 #define PRINT_BUFFER_SIZE       512
  49 #define PRINT_BUFFER_THRESHOLD  (PRINT_BUFFER_SIZE - 4)
  50
  51 UINTN
  52 EFIAPI
  53 SerialPortWrite (
  54   IN UINT8     *Buffer,
  55   IN UINTN     NumberOfBytes
  56 )
  57 {
  58   UINT8 PrintBuffer[PRINT_BUFFER_SIZE];
  59   UINTN SourceIndex;
  60   UINTN DestinationIndex;
  61   UINT8 CurrentCharacter;
  62
  63   SourceIndex      = 0;
  64   DestinationIndex = 0;
  65
  66   while (SourceIndex < NumberOfBytes)
  67   {
  68       CurrentCharacter = Buffer[SourceIndex++];
  69
  70       switch (CurrentCharacter)
  71       {
  72       case '\r':
  73           continue;
  74
  75       case '\n':
  76           PrintBuffer[DestinationIndex++] = ' ';
  77           // fall through
  78
  79       default:
  80           PrintBuffer[DestinationIndex++] = CurrentCharacter;
  81           break;
  82       }
  83
  84       if (DestinationIndex > PRINT_BUFFER_THRESHOLD)
  85       {
  86           PrintBuffer[DestinationIndex] = '\0';
  87           SemihostWriteString ((CHAR8 *) PrintBuffer);
  88
  89           DestinationIndex = 0;
  90       }
  91   }
  92
  93   if (DestinationIndex > 0)
  94   {
  95       PrintBuffer[DestinationIndex] = '\0';
  96       SemihostWriteString ((CHAR8 *) PrintBuffer);
  97   }
  98
  99   return NumberOfBytes;
 100 }
 101
 102
 103 /**
 104   Read data from serial device and save the datas in buffer.
 105
 106   @param  Buffer           Point of data buffer which need to be writed.
 107   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
 108
 109   @retval 0                Read data failed.
 110   @retval !0               Actual number of bytes read from serial device.
 111
 112 **/
 113 UINTN
 114 EFIAPI
 115 SerialPortRead (
 116   OUT UINT8     *Buffer,
 117   IN  UINTN     NumberOfBytes
 118 )
 119 {
 120   *Buffer = SemihostReadCharacter ();
 121   return 1;
 122 }
 123
 124
 125
 126 /**
 127   Check to see if any data is available to be read from the debug device.
 128
 129   @retval TRUE       At least one byte of data is available to be read
 130   @retval FALSE      No data is available to be read
 131
 132 **/
 133 BOOLEAN
 134 EFIAPI
 135 SerialPortPoll (
 136   VOID
 137   )
 138 {
 139   // Since SemiHosting read character is blocking always say we have a char ready?
 140   return SemihostConnectionSupported ();
 141 }
 142