windows-server-2003/drivers/serial/mps/spx/speed/driver/purge.c

/*++

Copyright (c) 1991, 1992, 1993 Microsoft Corporation

Module Name:

    purge.c

Abstract:

    This module contains the code that is very specific to purge
    operations in the serial driver

Author:

    Anthony V. Ercolano 26-Sep-1991

Environment:

    Kernel mode

Revision History :

--*/

#include "precomp.h"

#ifdef ALLOC_PRAGMA
#endif


NTSTATUS
SerialStartPurge(IN PPORT_DEVICE_EXTENSION pPort)
/*++

Routine Description:

    Depending on the mask in the current irp, purge the interrupt
    buffer, the read queue, or the write queue, or all of the above.

Arguments:

    Extension - Pointer to the device extension.

Return Value:

    Will return STATUS_SUCCESS always.  This is reasonable
    since the DPC completion code that calls this routine doesn't
    care and the purge request always goes through to completion
    once it's started.

--*/
{

    PIRP NewIrp;

    do 
	{
        ULONG Mask;

        Mask = *((ULONG *)(pPort->CurrentPurgeIrp->AssociatedIrp.SystemBuffer));
                 

        if(Mask & SERIAL_PURGE_TXABORT) 
		{
            SerialKillAllReadsOrWrites(pPort->DeviceObject, &pPort->WriteQueue, &pPort->CurrentWriteIrp);

            SerialKillAllReadsOrWrites(pPort->DeviceObject, &pPort->WriteQueue, &pPort->CurrentXoffIrp);
        }


        if(Mask & SERIAL_PURGE_RXABORT) 
            SerialKillAllReadsOrWrites(pPort->DeviceObject, &pPort->ReadQueue, &pPort->CurrentReadIrp);


        if(Mask & SERIAL_PURGE_RXCLEAR) 
		{
            KIRQL OldIrql;

            // Clean out the interrupt buffer.
            //
            // Note that we do this under protection of the
            // the drivers control lock so that we don't hose
            // the pointers if there is currently a read that
            // is reading out of the buffer.

            KeAcquireSpinLock(&pPort->ControlLock, &OldIrql);
                
            KeSynchronizeExecution(pPort->Interrupt, SerialPurgeInterruptBuff, pPort);

            KeReleaseSpinLock(&pPort->ControlLock, OldIrql);
        }

        pPort->CurrentPurgeIrp->IoStatus.Status = STATUS_SUCCESS;
        pPort->CurrentPurgeIrp->IoStatus.Information = 0;

        SerialGetNextIrp(pPort, &pPort->CurrentPurgeIrp, &pPort->PurgeQueue, &NewIrp, TRUE);

    } while (NewIrp);

    return STATUS_SUCCESS;
}


BOOLEAN
SerialPurgeInterruptBuff(IN PVOID Context)
/*++

Routine Description:

    This routine simply resets the interrupt (typeahead) buffer.

    NOTE: This routine is being called from KeSynchronizeExecution.

Arguments:

    Context - Really a pointer to the device extension.

Return Value:

    Always false.

--*/
{

    PPORT_DEVICE_EXTENSION pPort = Context;

	// Flush the IN buffer	
	pPort->pUartLib->UL_BufferControl_XXXX(pPort->pUart, NULL, UL_BC_OP_FLUSH, UL_BC_BUFFER | UL_BC_IN);

    SerialHandleReducedIntBuffer(pPort);

    return FALSE;
}