EmbeddedPkg/Library/SemiHostingSerialPortLib/SerialPortLib.c

   1 /** @file
   2   Serial I/O Port library functions with no library constructor/destructor
   3
   4
   5   Copyright (c) 2008-2009, Apple Inc. All rights reserved.
   6
   7   All rights reserved. This program and the accompanying materials
   8   are licensed and made available under the terms and conditions of the BSD License
   9   which accompanies this distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16
  17 #include <Uefi.h>
  18 #include <Library/DebugLib.h>
  19 #include <Library/SemihostLib.h>
  20 #include <Library/SerialPortLib.h>
  21
  22
  23 /*
  24
  25   Programmed hardware of Serial port.
  26
  27   @return    Always return EFI_UNSUPPORTED.
  28
  29 **/
  30 RETURN_STATUS
  31 EFIAPI
  32 SerialPortInitialize (
  33   VOID
  34   )
  35 {
  36   if (SemihostConnectionSupported ()) {
  37     return RETURN_SUCCESS;
  38   } else {
  39     return RETURN_UNSUPPORTED;
  40   }
  41 }
  42
  43 /**
  44   Write data to serial device.
  45
  46   @param  Buffer           Point of data buffer which need to be writed.
  47   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
  48
  49   @retval 0                Write data failed.
  50   @retval !0               Actual number of bytes writed to serial device.
  51
  52 **/
  53
  54 #define PRINT_BUFFER_SIZE       512
  55 #define PRINT_BUFFER_THRESHOLD  (PRINT_BUFFER_SIZE - 4)
  56
  57 UINTN
  58 EFIAPI
  59 SerialPortWrite (
  60   IN UINT8     *Buffer,
  61   IN UINTN     NumberOfBytes
  62 )
  63 {
  64   UINT8 PrintBuffer[PRINT_BUFFER_SIZE];
  65   UINTN SourceIndex      = 0;
  66   UINTN DestinationIndex = 0;
  67   UINT8 CurrentCharacter;
  68
  69   while (SourceIndex < NumberOfBytes)
  70   {
  71       CurrentCharacter = Buffer[SourceIndex++];
  72
  73       switch (CurrentCharacter)
  74       {
  75       case '\r':
  76           continue;
  77
  78       case '\n':
  79           PrintBuffer[DestinationIndex++] = ' ';
  80           // fall through
  81
  82       default:
  83           PrintBuffer[DestinationIndex++] = CurrentCharacter;
  84           break;
  85       }
  86
  87       if (DestinationIndex > PRINT_BUFFER_THRESHOLD)
  88       {
  89           PrintBuffer[DestinationIndex] = '\0';
  90           SemihostWriteString ((CHAR8 *) PrintBuffer);
  91
  92           DestinationIndex = 0;
  93       }
  94   }
  95
  96   if (DestinationIndex > 0)
  97   {
  98       PrintBuffer[DestinationIndex] = '\0';
  99       SemihostWriteString ((CHAR8 *) PrintBuffer);
 100   }
 101
 102   return 0;
 103 }
 104
 105
 106 /**
 107   Read data from serial device and save the datas in buffer.
 108
 109   @param  Buffer           Point of data buffer which need to be writed.
 110   @param  NumberOfBytes    Number of output bytes which are cached in Buffer.
 111
 112   @retval 0                Read data failed.
 113   @retval !0               Aactual number of bytes read from serial device.
 114
 115 **/
 116 UINTN
 117 EFIAPI
 118 SerialPortRead (
 119   OUT UINT8     *Buffer,
 120   IN  UINTN     NumberOfBytes
 121 )
 122 {
 123   *Buffer = SemihostReadCharacter ();
 124   return 1;
 125 }
 126
 127
 128
 129 /**
 130   Check to see if any data is avaiable to be read from the debug device.
 131
 132   @retval TRUE       At least one byte of data is avaiable to be read
 133   @retval FALS     No data is avaiable to be read
 134
 135 **/
 136 BOOLEAN
 137 EFIAPI
 138 SerialPortPoll (
 139   VOID
 140   )
 141 {
 142   // Since SemiHosting read character is blocking always say we have a char ready?
 143   return SemihostConnectionSupported ();
 144 }
 145