write.c

NXP产品LPC23XX的开发板的源文件

    // The rts line may already be up from previous writes,
    // however, it won't take much additional time to turn
    // on the RTS line if we are doing transmit toggling.
    //

    if ((Extension->HandFlow.FlowReplace & SERIAL_RTS_MASK) ==
        SERIAL_TRANSMIT_TOGGLE) {

        SerialSetRTS(Extension);

    }

    return FALSE;

}

VOID
SerialCancelCurrentWrite(
    PDEVICE_OBJECT DeviceObject,
    PIRP Irp
    )

/*++

Routine Description:

    This routine is used to cancel the current write.

Arguments:

    DeviceObject - Pointer to the device object for this device

    Irp - Pointer to the IRP to be canceled.

Return Value:

    None.

--*/

{

    PDEVICE_EXTENSION Extension = DeviceObject->DeviceExtension;
    //SERIAL_LOCKED_PAGED_CODE();

    SerialTryToCompleteCurrent(
        Extension,
        SerialGrabWriteFromIsr,
        Irp->CancelIrql,
        STATUS_CANCELLED,
        &Extension->CurrentWriteIrp,
        &Extension->WriteQueue,
        NULL,
        &Extension->WriteRequestTotalTimer,
        SerialStartWrite,
        SerialGetNextWrite,
        SERIAL_REF_CANCEL
        );

}

VOID
SerialWriteTimeout(
    IN PKDPC Dpc,
    IN PVOID DeferredContext,
    IN PVOID SystemContext1,
    IN PVOID SystemContext2
    )

/*++

Routine Description:

    This routine will try to timeout the current write.

Arguments:

    Dpc - Not Used.

    DeferredContext - Really points to the device extension.

    SystemContext1 - Not Used.

    SystemContext2 - Not Used.

Return Value:

    None.

--*/

{

    PDEVICE_EXTENSION Extension = DeferredContext;
    KIRQL OldIrql;

    UNREFERENCED_PARAMETER(SystemContext1);
    UNREFERENCED_PARAMETER(SystemContext2);

SerialDump(SERTRACECALLS, ("SERIAL: SerialWriteTimeout\n"));

    IoAcquireCancelSpinLock(&OldIrql);

    SerialTryToCompleteCurrent(
        Extension,
        SerialGrabWriteFromIsr,
        OldIrql,
        STATUS_TIMEOUT,
        &Extension->CurrentWriteIrp,
        &Extension->WriteQueue,
        NULL,
        &Extension->WriteRequestTotalTimer,
        SerialStartWrite,
        SerialGetNextWrite,
        SERIAL_REF_TOTAL_TIMER
        );

    SerialDpcEpilogue(Extension, Dpc);
}

BOOLEAN
SerialGrabWriteFromIsr(
    IN PVOID Context
    )

/*++

Routine Description:


    This routine is used to grab the current irp, which could be timing
    out or canceling, from the ISR

    NOTE: This routine is being called from KeSynchronizeExecution.

    NOTE: This routine assumes that the cancel spin lock is held
          when this routine is called.

Arguments:

    Context - Really a pointer to the device extension.

Return Value:

    Always false.

--*/

{

    PDEVICE_EXTENSION Extension = Context;
    //SERIAL_LOCKED_PAGED_CODE();

    //
    // Check if the write length is non-zero.  If it is non-zero
    // then the ISR still owns the irp. We calculate the the number
    // of characters written and update the information field of the
    // irp with the characters written.  We then clear the write length
    // the isr sees.
    //

    if (Extension->WriteLength) {

        //
        // We could have an xoff counter masquerading as a
        // write irp.  If so, don't update the write length.
        //

        if (IoGetCurrentIrpStackLocation(Extension->CurrentWriteIrp)
            ->MajorFunction == IRP_MJ_WRITE) {

            Extension->CurrentWriteIrp->IoStatus.Information =
                IoGetCurrentIrpStackLocation(
                    Extension->CurrentWriteIrp
                    )->Parameters.Write.Length -
                Extension->WriteLength;

        } else {

            Extension->CurrentWriteIrp->IoStatus.Information = 0;

        }

        //
        // Since the isr no longer references this irp, we can
        // decrement it's reference count.
        //

        SERIAL_CLEAR_REFERENCE(
            Extension->CurrentWriteIrp,
            SERIAL_REF_ISR
            );

        Extension->WriteLength = 0;

    }

    return FALSE;

}

BOOLEAN
SerialGrabXoffFromIsr(
    IN PVOID Context
    )

/*++

Routine Description:

    This routine is used to grab an xoff counter irp from the
    isr when it is no longer masquerading as a write irp.  This
    routine is called by the cancel and timeout code for the
    xoff counter ioctl.


    NOTE: This routine is being called from KeSynchronizeExecution.

    NOTE: This routine assumes that the cancel spin lock is held
          when this routine is called.

Arguments:

    Context - Really a pointer to the device extension.

Return Value:

    Always false.

--*/

{

    PDEVICE_EXTENSION Extension = Context;
    //SERIAL_LOCKED_PAGED_CODE();

    if (Extension->CountSinceXoff) {

        //
        // This is only non-zero when there actually is a Xoff ioctl
        // counting down.
        //

        Extension->CountSinceXoff = 0;

        //
        // We decrement the count since the isr no longer owns
        // the irp.
        //

        SERIAL_CLEAR_REFERENCE(
            Extension->CurrentXoffIrp,
            SERIAL_REF_ISR
            );

    }

    return FALSE;

}

VOID
SerialCompleteXoff(
    IN PKDPC Dpc,
    IN PVOID DeferredContext,
    IN PVOID SystemContext1,
    IN PVOID SystemContext2
    )

/*++

Routine Description:

    This routine is merely used to truely complete an xoff counter irp.  It
    assumes that the status and the information fields of the irp are
    already correctly filled in.

Arguments:

    Dpc - Not Used.

    DeferredContext - Really points to the device extension.

    SystemContext1 - Not Used.

    SystemContext2 - Not Used.

Return Value:

    None.

--*/

{

    PDEVICE_EXTENSION Extension = DeferredContext;
    KIRQL OldIrql;

    UNREFERENCED_PARAMETER(SystemContext1);
    UNREFERENCED_PARAMETER(SystemContext2);

    SerialDump(SERTRACECALLS, ("SERIAL: SerialCompleteXoff\n"));

    IoAcquireCancelSpinLock(&OldIrql);

    SerialTryToCompleteCurrent(
        Extension,
        NULL,
        OldIrql,
        STATUS_SUCCESS,
        &Extension->CurrentXoffIrp,
        NULL,
        NULL,
        &Extension->XoffCountTimer,
        NULL,
        NULL,
        SERIAL_REF_ISR
        );

    SerialDpcEpilogue(Extension, Dpc);

}

VOID
SerialTimeoutXoff(
    IN PKDPC Dpc,
    IN PVOID DeferredContext,
    IN PVOID SystemContext1,
    IN PVOID SystemContext2
    )

/*++

Routine Description:

    This routine is merely used to truely complete an xoff counter irp,
    if its timer has run out.

Arguments:

    Dpc - Not Used.

    DeferredContext - Really points to the device extension.

    SystemContext1 - Not Used.

    SystemContext2 - Not Used.

Return Value:

    None.

--*/

{

    PDEVICE_EXTENSION Extension = DeferredContext;
    KIRQL OldIrql;

    UNREFERENCED_PARAMETER(SystemContext1);
    UNREFERENCED_PARAMETER(SystemContext2);

    SerialDump(SERTRACECALLS, ("SERIAL: SerialTimeoutXoff\n"));

    IoAcquireCancelSpinLock(&OldIrql);

    SerialTryToCompleteCurrent(
        Extension,
        SerialGrabXoffFromIsr,
        OldIrql,
        STATUS_SERIAL_COUNTER_TIMEOUT,
        &Extension->CurrentXoffIrp,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        SERIAL_REF_TOTAL_TIMER
        );

    SerialDpcEpilogue(Extension, Dpc);

}

VOID
SerialCancelCurrentXoff(
    PDEVICE_OBJECT DeviceObject,
    PIRP Irp
    )

/*++

Routine Description:

    This routine is used to cancel the current write.

Arguments:

    DeviceObject - Pointer to the device object for this device

    Irp - Pointer to the IRP to be canceled.

Return Value:

    None.

--*/

{

    PDEVICE_EXTENSION Extension = DeviceObject->DeviceExtension;
    //SERIAL_LOCKED_PAGED_CODE();

    SerialTryToCompleteCurrent(
        Extension,
        SerialGrabXoffFromIsr,
        Irp->CancelIrql,
        STATUS_CANCELLED,
        &Extension->CurrentXoffIrp,
        NULL,
        NULL,
        &Extension->XoffCountTimer,
        NULL,
        NULL,
        SERIAL_REF_CANCEL
        );

}

BOOLEAN
SerialGiveXoffToIsr(
    IN PVOID Context
    )

/*++

Routine Description:


    This routine starts off the xoff counter.  It merely
    has to set the xoff count and increment the reference
    count to denote that the isr has a reference to the irp.

    NOTE: This routine is called by KeSynchronizeExecution.

    NOTE: This routine assumes that it is called with the
          cancel spin lock held.

Arguments:

    Context - Really a pointer to the device extension.

Return Value:

    This routine always returns FALSE.

--*/

{

    PDEVICE_EXTENSION Extension = Context;

    //
    // The current stack location.  This contains all of the
    // information we need to process this particular request.
    //

    PSERIAL_XOFF_COUNTER Xc =
        Extension->CurrentXoffIrp->AssociatedIrp.SystemBuffer;

    //SERIAL_LOCKED_PAGED_CODE();

    ASSERT(Extension->CurrentXoffIrp);
    Extension->CountSinceXoff = Xc->Counter;

    //
    // The isr now has a reference to the irp.
    //

    SERIAL_SET_REFERENCE(
        Extension->CurrentXoffIrp,
        SERIAL_REF_ISR
        );

    return FALSE;

}