drivers/base/kdcom/kdserial.c

   1 /*
   2  * COPYRIGHT:       GPL, see COPYING in the top level directory
   3  * PROJECT:         ReactOS kernel
   4  * FILE:            drivers/base/kddll/kdserial.c
   5  * PURPOSE:         Serial communication functions for the kernel debugger.
   6  * PROGRAMMER:      Timo Kreuzer (timo.kreuzer@ewactos.org)
   7  */
   8
   9 #include "kddll.h"
  10
  11 #define NDEBUG
  12 #include <debug.h>
  13
  14 /* FUNCTIONS ******************************************************************/
  15
  16 /******************************************************************************
  17  * \name KdpSendBuffer
  18  * \brief Sends a buffer of data to the serial KD port.
  19  * \param Buffer Pointer to the data.
  20  * \param Size Size of data in bytes.
  21  */
  22 VOID
  23 NTAPI
  24 KdpSendBuffer(
  25     IN PVOID Buffer,
  26     IN ULONG Size)
  27 {
  28     PUCHAR ByteBuffer = Buffer;
  29
  30     while (Size-- > 0)
  31     {
  32         KdpSendByte(*ByteBuffer++);
  33     }
  34 }
  35
  36 /******************************************************************************
  37  * \name KdpReceiveBuffer
  38  * \brief Receives data from the KD port and fills a buffer.
  39  * \param Buffer Pointer to a buffer that receives the data.
  40  * \param Size Size of data to receive in bytes.
  41  * \return KDP_PACKET_RECEIVED if successful.
  42  *         KDP_PACKET_TIMEOUT if the receice timed out.
  43  */
  44 KDP_STATUS
  45 NTAPI
  46 KdpReceiveBuffer(
  47     OUT PVOID Buffer,
  48     IN  ULONG Size)
  49 {
  50     PUCHAR ByteBuffer = Buffer;
  51     UCHAR Byte;
  52     KDP_STATUS Status;
  53
  54     while (Size-- > 0)
  55     {
  56         /* Try to get a byte from the port */
  57         Status = KdpReceiveByte(&Byte);
  58         if (Status != KDP_PACKET_RECEIVED)
  59             return Status;
  60
  61         *ByteBuffer++ = Byte;
  62     }
  63
  64     return KDP_PACKET_RECEIVED;
  65 }
  66
  67
  68 /******************************************************************************
  69  * \name KdpReceivePacketLeader
  70  * \brief Receives a packet leadr from the KD port.
  71  * \param PacketLeader Pointer to an ULONG that receives the packet leader.
  72  * \return KDP_PACKET_RECEIVED if successful.
  73  *         KDP_PACKET_TIMEOUT if the receive timed out.
  74  *         KDP_PACKET_RESEND if a breakin byte was detected.
  75  */
  76 KDP_STATUS
  77 NTAPI
  78 KdpReceivePacketLeader(
  79     OUT PULONG PacketLeader)
  80 {
  81     UCHAR Index = 0, Byte, Buffer[4];
  82     KDP_STATUS KdStatus;
  83
  84     /* Set first character to 0 */
  85     Buffer[0] = 0;
  86
  87     do
  88     {
  89         /* Receive a single byte */
  90         KdStatus = KdpReceiveByte(&Byte);
  91
  92         /* Check for timeout */
  93         if (KdStatus == KDP_PACKET_TIMEOUT)
  94         {
  95             /* Check if we already got a breakin byte */
  96             if (Buffer[0] == BREAKIN_PACKET_BYTE)
  97             {
  98                 return KDP_PACKET_RESEND;
  99             }
 100
 101             /* Report timeout */
 102             return KDP_PACKET_TIMEOUT;
 103         }
 104
 105         /* Check if we received a byte */
 106         if (KdStatus == KDP_PACKET_RECEIVED)
 107         {
 108             /* Check if this is a valid packet leader byte */
 109             if (Byte == PACKET_LEADER_BYTE ||
 110                 Byte == CONTROL_PACKET_LEADER_BYTE)
 111             {
 112                 /* Check if we match the first byte */
 113                 if (Byte != Buffer[0])
 114                 {
 115                     /* No, this is the new byte 0! */
 116                     Index = 0;
 117                 }
 118
 119                 /* Store the byte in the buffer */
 120                 Buffer[Index] = Byte;
 121
 122                 /* Continue with next byte */
 123                 Index++;
 124                 continue;
 125             }
 126
 127             /* Check for breakin byte */
 128             if (Byte == BREAKIN_PACKET_BYTE)
 129             {
 130                 KDDBGPRINT("BREAKIN_PACKET_BYTE\n");
 131                 Index = 0;
 132                 Buffer[0] = Byte;
 133                 continue;
 134             }
 135         }
 136
 137         /* Restart */
 138         Index = 0;
 139         Buffer[0] = 0;
 140     }
 141     while (Index < 4);
 142
 143     /* Enable the debugger */
 144     KD_DEBUGGER_NOT_PRESENT = FALSE;
 145     SharedUserData->KdDebuggerEnabled |= 0x00000002;
 146
 147     /* Return the received packet leader */
 148     *PacketLeader = *(PULONG)Buffer;
 149
 150     return KDP_PACKET_RECEIVED;
 151 }
 152
 153 /* EOF */