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.
   5
   6   All rights reserved. This program and the accompanying materials
   7   are licensed and made available under the terms and conditions of the BSD License
   8   which accompanies this distribution.  The full text of the license may be found at
   9   http://opensource.org/licenses/bsd-license.php
  10
  11   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 **/
  15
  16 #include <Uefi.h>
  17 #include <Library/DebugLib.h>
  18 #include <Library/SemihostLib.h>
  19 #include <Library/SerialPortLib.h>
  20
  21
  22 /*
  23
  24   Programmed hardware of Serial port.
  25
  26   @return    Always return EFI_UNSUPPORTED.
  27
  28 **/
  29 RETURN_STATUS
  30 EFIAPI
  31 SerialPortInitialize (
  32   VOID
  33   )
  34 {
  35   if (SemihostConnectionSupported ()) {
  36     return RETURN_SUCCESS;
  37   } else {
  38     return RETURN_UNSUPPORTED;
  39   }
  40 }
  41
  42 /**
  43   Write data to serial device.
  44
  45   @param  Buffer           Point of data buffer which need to be writed.
  46   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
  47
  48   @retval 0                Write data failed.
  49   @retval !0               Actual number of bytes writed to serial device.
  50
  51 **/
  52
  53 #define PRINT_BUFFER_SIZE       512
  54 #define PRINT_BUFFER_THRESHOLD  (PRINT_BUFFER_SIZE - 4)
  55
  56 UINTN
  57 EFIAPI
  58 SerialPortWrite (
  59   IN UINT8     *Buffer,
  60   IN UINTN     NumberOfBytes
  61 )
  62 {
  63   UINT8 PrintBuffer[PRINT_BUFFER_SIZE];
  64   UINTN SourceIndex      = 0;
  65   UINTN DestinationIndex = 0;
  66   UINT8 CurrentCharacter;
  67
  68   while (SourceIndex < NumberOfBytes)
  69   {
  70       CurrentCharacter = Buffer[SourceIndex++];
  71
  72       switch (CurrentCharacter)
  73       {
  74       case '\r':
  75           continue;
  76
  77       case '\n':
  78           PrintBuffer[DestinationIndex++] = ' ';
  79           // fall through
  80
  81       default:
  82           PrintBuffer[DestinationIndex++] = CurrentCharacter;
  83           break;
  84       }
  85
  86       if (DestinationIndex > PRINT_BUFFER_THRESHOLD)
  87       {
  88           PrintBuffer[DestinationIndex] = '\0';
  89           SemihostWriteString ((CHAR8 *) PrintBuffer);
  90
  91           DestinationIndex = 0;
  92       }
  93   }
  94
  95   if (DestinationIndex > 0)
  96   {
  97       PrintBuffer[DestinationIndex] = '\0';
  98       SemihostWriteString ((CHAR8 *) PrintBuffer);
  99   }
 100
 101   return 0;
 102 }
 103
 104
 105 /**
 106   Read data from serial device and save the datas in buffer.
 107
 108   @param  Buffer           Point of data buffer which need to be writed.
 109   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
 110
 111   @retval 0                Read data failed.
 112   @retval !0               Aactual number of bytes read from serial device.
 113
 114 **/
 115 UINTN
 116 EFIAPI
 117 SerialPortRead (
 118   OUT UINT8     *Buffer,
 119   IN  UINTN     NumberOfBytes
 120 )
 121 {
 122   *Buffer = SemihostReadCharacter ();
 123   return 1;
 124 }
 125
 126
 127
 128 /**
 129   Check to see if any data is avaiable to be read from the debug device.
 130
 131   @retval TRUE       At least one byte of data is avaiable to be read
 132   @retval FALSE      No data is avaiable to be read
 133
 134 **/
 135 BOOLEAN
 136 EFIAPI
 137 SerialPortPoll (
 138   VOID
 139   )
 140 {
 141   // Since SemiHosting read character is blocking always say we have a char ready?
 142   return SemihostConnectionSupported ();
 143 }
 144