mdd.c

wince4.2 USB function driver for magic eye mmsp2 platform

     */
    if ( MAXDWORD != pSerialHead->CommTimeouts.ReadTotalTimeoutMultiplier ) {
        TotalTimeout = pSerialHead->CommTimeouts.ReadTotalTimeoutMultiplier*BufferLength +
                       pSerialHead->CommTimeouts.ReadTotalTimeoutConstant;
    } else {
        TotalTimeout = pSerialHead->CommTimeouts.ReadTotalTimeoutConstant;
    }
    IntervalTimeout = pSerialHead->CommTimeouts.ReadIntervalTimeout;

    DEBUGMSG (ZONE_USR_READ, (TEXT("TotalTimeout:%d\r\n"), TotalTimeout));

    while ( BufferLength ) {
        DEBUGMSG (ZONE_USR_READ,
                  (TEXT("Top of Loop Fifo(R=%d,W=%d,L=%d,BA=%d)\r\n"),
                   RxRead(pSerialHead), RxWrite(pSerialHead),
                   RxLength(pSerialHead),
                   RxBytesAvail(pSerialHead)));
        if ( RxBytesAvail(pSerialHead) ) {
            RxEnterCS(pSerialHead);
            // Copy the data over
            // This only copies the continous portion, This will cause a loop
            // if the receive data spans the end of the buffer.
            Len = MIN(RxBytesAvail(pSerialHead),
                      RxLength(pSerialHead)-RxRead(pSerialHead));
            Len = MIN(Len, BufferLength);
            DEBUGMSG (ZONE_USR_READ, (TEXT("About to copy %d bytes\r\n"), Len));
            memcpy (pTargetBuffer, RxBuffRead(pSerialHead), Len);
            // Update Fifo info
            RxRead(pSerialHead) = 
                (RxRead(pSerialHead)+ Len<RxLength(pSerialHead)? RxRead(pSerialHead)+Len: RxRead(pSerialHead)+Len-RxLength(pSerialHead));

            // Update all the pointers.
            BufferLength -= Len;
            pTargetBuffer += Len;
            BytesRead += Len;
            RxLeaveCS(pSerialHead);
        } else {
            // Wait for a serial event?
            if ( IntervalTimeout == MAXDWORD){  // Special Case see Remarks of COMMTIMEOUTS 
                if (TotalTimeout == 0) 
                    // For some reason this means don't wait.
                    break;
                else
                if (BytesRead!=0) // There is a data in buffer or has been readed.
                    break;
            }
            Timeout=(TotalTimeout!=0?TotalTimeout:MAXDWORD);
            // Total timeout is valid
            if ( TimeSpent >= Timeout ) {
                // Timed out.
                break;
            }
            Timeout -= TimeSpent;
            // On first byte we only use interval timeout
            // on subsequent we use minimum of Interval and Timeout
            if ( BytesRead) {
                Timeout = MIN(Timeout, (IntervalTimeout!=0?IntervalTimeout:MAXDWORD));
            }
            Ticks = GetTickCount();
            DEBUGMSG (ZONE_USR_READ, (TEXT("About to wait %dms\r\n"), Timeout));

            if ( WAIT_TIMEOUT == WaitForSingleObject (pSerialHead->hReadEvent,
                                                      Timeout) ) {
                // Timeout
                break;
            }
            // Since ticks is a ULONG this handles wrap.
            Ticks = GetTickCount() - Ticks;
            TimeSpent += Ticks;

            // In the absense of WaitForMultipleObjects, we use flags to
            // handle errors/aborts. Check for aborts or asynchronous closes.
            if ( pSerialHead->fAbortRead ) {
                DEBUGMSG(ZONE_USR_READ,(TEXT("COM_Read - Aborting read\r\n")));
                break;
            }

            if ( !pSerialHead->OpenCnt ) {
                DEBUGMSG(ZONE_USR_READ|ZONE_ERROR,
                         (TEXT("COM_Read - device was closed\n\r")));
                SetLastError(ERROR_INVALID_HANDLE);
                break;
            }
        }

        // Are we below the SW flow control limits?
        if ( pSerialHead->DCB.fInX && pSerialHead->SentXoff &&
             (pSerialHead->DCB.XoffLim <
              (RxLength(pSerialHead) - RxBytesAvail(pSerialHead))) ) {
            PHWOBJ  pHWObj  = pSerialHead->pHWObj;

            DEBUGMSG (ZONE_FLOW, (TEXT("Sending XON\r\n")));
            pSerialHead->SentXoff = 0;
            if ( !pSerialHead->DCB.fTXContinueOnXoff ) {
                pSerialHead->StopXmit = 0;
            }
            pHWObj->pFuncTbl->HWXmitComChar(pSerialHead->pHWHead,
                                            pSerialHead->DCB.XonChar);
        }

        // Are we below the HW flow control limits?
        if ( 2*RxBytesAvail(pSerialHead) < RxLength(pSerialHead) ) {
            // When buffer is less then 1/2 full we set RTS/DTR
            if ( pSerialHead->RtsFlow &&
                 (pSerialHead->DCB.fRtsControl == RTS_CONTROL_HANDSHAKE) ) {
                DEBUGMSG (ZONE_USR_READ|ZONE_FLOW,
                          (TEXT("RTS_CONTROL_HANDSHAKE Setting RTS\r\n")));
                pSerialHead->RtsFlow = 0;
                pFuncTbl->HWSetRTS(pHWHead);
            }
            if ( pSerialHead->DtrFlow && 
                 (pSerialHead->DCB.fDtrControl == DTR_CONTROL_HANDSHAKE) ) {
                DEBUGMSG (ZONE_USR_READ|ZONE_FLOW,
                          (TEXT("DTR_CONTROL_HANDSHAKE Setting DTR\r\n")));
                pSerialHead->DtrFlow = 0;
                pFuncTbl->HWSetDTR(pHWHead);
            }
        }

    }

    DEBUGMSG (ZONE_USR_READ, (TEXT("ReceiveBytes exiting\r\n")));

    LeaveCriticalSection(&(pSerialHead->ReceiveCritSec1));

    DEBUGMSG (ZONE_USR_READ|ZONE_FUNCTION,
              (TEXT("-COM_READ: returning %d (total %d, dropped %d,%d)\r\n"),
               BytesRead, pSerialHead->RxBytes, pSerialHead->DroppedBytesMDD,pSerialHead->DroppedBytesPDD));

    COM_DEC_USAGE_CNT(pOpenHead);
    return(BytesRead);
}

/*
   @doc EXTERNAL
   @func ULONG | COM_Write | Allows application to transmit bytes to the serial port. Exported to users.
   *
   @rdesc It returns the number of bytes written or -1 if error.
   *
   *
   */
ULONG
COM_Write(HANDLE pHead,         /*@parm [IN]  HANDLE returned by COM_Open.*/
          PUCHAR pSourceBytes,  /*@parm [IN]  Pointer to bytes to be written.*/
          ULONG  NumberOfBytes  /*@parm [IN]  Number of bytes to be written. */
         )
{
    PHW_OPEN_INFO   pOpenHead = (PHW_OPEN_INFO)pHead;
    PHW_INDEP_INFO  pSerialHead = pOpenHead->pSerialHead;
    ULONG               BytesWritten   = 0;
    ULONG               TotalWritten   = 0;
    PHWOBJ              pHWObj         = NULL;
    PVOID               pHWHead        = NULL;
    PHW_VTBL            pFuncTbl       = NULL;
    ULONG               TotalTimeout;   // The Total Timeout
    ULONG               Timeout;   // The Total Timeout
    ULONG               Ticks;          // Time for a loop.
    ULONG               TimeSpent = 0;  // How much time have we been waiting?
    ULONG               WaitReturn;
    ULONG               PutRet;

    DEBUGMSG (ZONE_WRITE|ZONE_FUNCTION,
              (TEXT("+COM_WRITE(0x%X, 0x%X, %d)\r\n"), pHead,
               pSourceBytes, NumberOfBytes));       


    // Check validity of handle
    if ( !pSerialHead || !pSerialHead->OpenCnt ) {
        DEBUGMSG (ZONE_WRITE|ZONE_ERROR,
                  (TEXT("COM_WRITE, device not open\r\n") ));
        SetLastError (ERROR_INVALID_HANDLE);
        return (ULONG)-1;
    }

    // Make sure the caller has access permissions
    if ( !(pOpenHead->AccessCode & GENERIC_WRITE) ) {
        DEBUGMSG(ZONE_USR_READ|ZONE_ERROR,
                 (TEXT("COM_Write: Access permission failure x%X\n\r"),
                  pOpenHead->AccessCode));
        SetLastError (ERROR_INVALID_ACCESS);
        return (ULONG)-1;
    }

#ifdef DEBUG
    if ( IsBadReadPtr(pSourceBytes, NumberOfBytes) ) {
        DEBUGMSG (ZONE_WRITE|ZONE_ERROR,
                  (TEXT("COM_WRITE, bad read pointer\r\n") ));
        SetLastError(ERROR_INVALID_PARAMETER);
        return (ULONG)-1;
    }
#endif

    COM_INC_USAGE_CNT(pOpenHead);

    pHWObj   = pSerialHead->pHWObj;
    pHWHead  = pSerialHead->pHWHead;
    pFuncTbl = pHWObj->pFuncTbl;

    /* Lock out other threads from messing with these pointers.
     */
    DEBUGMSG (ZONE_WRITE, (TEXT("COM_Write wait for CritSec %x.\r\n"),
                           &(pSerialHead->TransmitCritSec1)));
    EnterCriticalSection(&(pSerialHead->TransmitCritSec1));
    DEBUGMSG (ZONE_WRITE, (TEXT("COM_Write Got CritSec %x.\r\n"),
                           &(pSerialHead->TransmitCritSec1)));

    pSerialHead->fAbortTransmit = 0;
    // Clear any pending event
    WaitForSingleObject(pSerialHead->hTransmitEvent,0);

    pSerialHead->TxBytesPending = NumberOfBytes;

    TotalTimeout = pSerialHead->CommTimeouts.WriteTotalTimeoutMultiplier*NumberOfBytes +
                   pSerialHead->CommTimeouts.WriteTotalTimeoutConstant;

    Ticks = GetTickCount();

    while ( 1 ) {
        /* Check used flag to see if there are no users the device.
         */
        if ( !pSerialHead->OpenCnt ) {
            break;
        }

        if ( NumberOfBytes ) {
            if ( pSerialHead->DCB.fRtsControl == RTS_CONTROL_TOGGLE ) {
                pFuncTbl->HWSetRTS(pHWHead);
            }

            // Don't call PutBytes if we are flowed off.
            if ( !pSerialHead->StopXmit ) {
                PutRet = pFuncTbl->HWPutBytes(pHWHead, pSourceBytes, NumberOfBytes,
                                              &BytesWritten);
            } else {
                // If we are flowed off, then no bytes were written.  For now, we
                // will set PutRet to 10 to cause polling for a flow-on condition.
                // We could change this so that XON generates a TX Event and then
                // we could wait forever (i.e. PutRet = 0).
                BytesWritten = 0;
                PutRet = 10;
            }

        } else {
            break;
        }

        pSerialHead->TxBytes += BytesWritten;

        if ( BytesWritten ) {
            TotalWritten += BytesWritten;
            NumberOfBytes -= BytesWritten;
            pSourceBytes += BytesWritten;

            DEBUGMSG (ZONE_WRITE,
                      (TEXT("COM_Write: wrote %d, remaining %d\r\n"),
                       BytesWritten, NumberOfBytes));
            BytesWritten    = 0;
        }

        // If data still left, wait until the Dispatch thread has
        // signalled that a transmit event has occurred and try again.
        if ( NumberOfBytes ) {
            DEBUGMSG (ZONE_WRITE,
                      (TEXT("COM_Write awaiting xmit event, %d bytes remain\r\n"),
                       NumberOfBytes));

            // Calculate the timeout
            if ( !TotalTimeout ) {
                Timeout = (ULONG)-1;
            } else if ( TimeSpent >= TotalTimeout ) {
                DEBUGMSG (ZONE_WARN,
                          (TEXT("COM_Write - Timeout1 (%d written, %d remain)\r\n"),
                           TotalWritten, NumberOfBytes));
                break;
            } else {
                Timeout = TotalTimeout - TimeSpent;
            }
            if ( PutRet ) {
                // If HWPutBytes returns true, then we need
                // to call back (after a pdd specified interval) to
                // see if the flow control condition has
                // been removed.
                Timeout = (Timeout > PutRet) ? PutRet : Timeout;
            }

            Ticks = GetTickCount();
            DEBUGMSG (ZONE_WRITE,
                      (TEXT("COM_WRITE: About to wait for %dms\r\n"),
                       Timeout));

            WaitReturn = WaitForSingleObject(pSerialHead->hTransmitEvent, Timeout);

            Ticks = GetTickCount() - Ticks;
            TimeSpent += Ticks;

            // In the absense of WaitForMultipleObjects, we use flags to
            // handle errors/aborts. Check for aborts or asynchronous closes.
            if ( pSerialHead->fAbortTransmit ) {
                DEBUGMSG(ZONE_USR_READ,(TEXT("COM_Write - Aborting write\r\n")));
                break;
            }

            if ( !pSerialHead->OpenCnt ) {
                DEBUGMSG(ZONE_WRITE|ZONE_ERROR,
                         (TEXT("COM_Write - device was closed\n\r")));
                SetLastError(ERROR_INVALID_HANDLE);
                break;
            }

            if ( WaitReturn == WAIT_TIMEOUT ) {
                // If we were told to wait by the pdd, then loop again
                // otherwise it is a write timeout
                if ( ! PutRet ) {
                    DEBUGMSG (ZONE_WARN,
                              (TEXT("COM_Write - Timeout2 (%d written, %d remain)\r\n"),
                               TotalWritten, NumberOfBytes));
                    break;
                }

            }
        }

        pSerialHead->TxBytesPending = NumberOfBytes;
    }

    LeaveCriticalSection(&(pSerialHead->TransmitCritSec1));

    DEBUGMSG (ZONE_WRITE|ZONE_FUNCTION,
              (TEXT("COM_Write released CritSec: %x. Exiting\r\n"),
               &(pSerialHead->TransmitCritSec1)));

    /* OK, the Transmitter has gone empty.
     */
    EvaluateEventFlag(pSerialHead, EV_TXEMPTY);

    if ( pSerialHead->DCB.fRtsControl == RTS_CONTROL_TOGGLE ) {
        pFuncTbl->HWClearRTS(pHWHead);
    }

    COM_DEC_USAGE_CNT(pOpenHead);