device.cpp

实现avstream流的驱动程序

void
CCaptureDevice::
ReleaseHardwareResources (
    )

/*++

Routine Description:

    Release hardware resources.  This should only be called by
    an object which has acquired them.

Arguments:

    None

Return Value:

    None

--*/

{

    PAGED_CODE();

    //
    // Blow away the image synth.
    //
    if (m_ImageSynth) {
        delete m_ImageSynth;
        m_ImageSynth = NULL;

    }

    m_VideoInfoHeader = NULL;
    m_CaptureSink = NULL;

    //
    // Release our "lock" on hardware resources.  This will allow another
    // pin (perhaps in another graph) to acquire them.
    //
    InterlockedExchange (
        &m_PinsWithResources,
        0
        );

}

/*************************************************/


NTSTATUS
CCaptureDevice::
Start (
    )

/*++

Routine Description:

    Start the capture device based on the video info header we were told
    about when resources were acquired.

Arguments:

    None

Return Value:

    Success / Failure

--*/

{

    PAGED_CODE();

    m_LastMappingsCompleted = 0;
    m_InterruptTime = 0;

    return
        m_HardwareSimulation -> Start (
            m_ImageSynth,
            m_VideoInfoHeader -> AvgTimePerFrame,
            m_VideoInfoHeader -> bmiHeader.biWidth,
            ABS (m_VideoInfoHeader -> bmiHeader.biHeight),
            m_VideoInfoHeader -> bmiHeader.biSizeImage
            );


}

/*************************************************/


NTSTATUS
CCaptureDevice::
Pause (
    IN BOOLEAN Pausing
    )

/*++

Routine Description:

    Pause or unpause the hardware simulation.  This is an effective start
    or stop without resetting counters and formats.  Note that this can
    only be called to transition from started -> paused -> started.  Calling
    this without starting the hardware with Start() does nothing.

Arguments:

    Pausing -
        An indicatation of whether we are pausing or unpausing

        TRUE -
            Pause the hardware simulation

        FALSE -
            Unpause the hardware simulation

Return Value:

    Success / Failure

--*/

{

    PAGED_CODE();

    return
        m_HardwareSimulation -> Pause (
            Pausing
            );

}

/*************************************************/


NTSTATUS
CCaptureDevice::
Stop (
    )

/*++

Routine Description:

    Stop the capture device.

Arguments:

    None

Return Value:

    Success / Failure

--*/

{

    PAGED_CODE();

    return
        m_HardwareSimulation -> Stop ();

}

/*************************************************/


ULONG
CCaptureDevice::
ProgramScatterGatherMappings (
    IN PUCHAR *Buffer,
    IN PKSMAPPING Mappings,
    IN ULONG MappingsCount
    )

/*++

Routine Description:

    Program the scatter / gather mappings for the "fake" hardware.

Arguments:

    Buffer -
        Points to a pointer to the virtual address of the topmost
        scatter / gather chunk.  The pointer will be updated as the
        device "programs" mappings.  Reason for this is that we get
        the physical addresses and sizes, but must calculate the virtual
        addresses...  This is used as scratch space for that.

    Mappings -
        An array of mappings to program

    MappingsCount -
        The count of mappings in the array

Return Value:

    The number of mappings successfully programmed

--*/

{

    PAGED_CODE();

    return 
        m_HardwareSimulation -> ProgramScatterGatherMappings (
            Buffer,
            Mappings,
            MappingsCount,
            sizeof (KSMAPPING)
            );

}

/*************************************************************************

    LOCKED CODE

**************************************************************************/

#ifdef ALLOC_PRAGMA
#pragma code_seg()
#endif // ALLOC_PRAGMA


ULONG
CCaptureDevice::
QueryInterruptTime (
    )

/*++

Routine Description:

    Return the number of frame intervals that have elapsed since the
    start of the device.  This will be the frame number.

Arguments:

    None

Return Value:

    The interrupt time of the device (the number of frame intervals that
    have elapsed since the start of the device).

--*/

{

    return m_InterruptTime;

}

/*************************************************/


void
CCaptureDevice::
Interrupt (
    )

/*++

Routine Description:

    This is the "faked" interrupt service routine for this device.  It
    is called at dispatch level by the hardware simulation.

Arguments:

    None

Return Value:

    None

--*/

{

    m_InterruptTime++;

    //
    // Realistically, we'd do some hardware manipulation here and then queue
    // a DPC.  Since this is fake hardware, we do what's necessary here.  This
    // is pretty much what the DPC would look like short of the access
    // of hardware registers (ReadNumberOfMappingsCompleted) which would likely
    // be done in the ISR.
    //
    ULONG NumMappingsCompleted = 
        m_HardwareSimulation -> ReadNumberOfMappingsCompleted ();

    //
    // Inform the capture sink that a given number of scatter / gather
    // mappings have completed.
    //
    m_CaptureSink -> CompleteMappings (
        NumMappingsCompleted - m_LastMappingsCompleted
        );

    m_LastMappingsCompleted = NumMappingsCompleted;

}

/**************************************************************************

    DESCRIPTOR AND DISPATCH LAYOUT

**************************************************************************/

//
// CaptureFilterDescriptor:
//
// The filter descriptor for the capture device.
DEFINE_KSFILTER_DESCRIPTOR_TABLE (FilterDescriptors) { 
    &CaptureFilterDescriptor
};

//
// CaptureDeviceDispatch:
//
// This is the dispatch table for the capture device.  Plug and play
// notifications as well as power management notifications are dispatched
// through this table.
//
const
KSDEVICE_DISPATCH
CaptureDeviceDispatch = {
    CCaptureDevice::DispatchCreate,         // Pnp Add Device
    CCaptureDevice::DispatchPnpStart,       // Pnp Start
    NULL,                                   // Post-Start
    NULL,                                   // Pnp Query Stop
    NULL,                                   // Pnp Cancel Stop
    CCaptureDevice::DispatchPnpStop,        // Pnp Stop
    NULL,                                   // Pnp Query Remove
    NULL,                                   // Pnp Cancel Remove
    NULL,                                   // Pnp Remove
    NULL,                                   // Pnp Query Capabilities
    NULL,                                   // Pnp Surprise Removal
    NULL,                                   // Power Query Power
    NULL,                                   // Power Set Power
    NULL                                    // Pnp Query Interface
};

//
// CaptureDeviceDescriptor:
//
// This is the device descriptor for the capture device.  It points to the
// dispatch table and contains a list of filter descriptors that describe
// filter-types that this device supports.  Note that the filter-descriptors
// can be created dynamically and the factories created via 
// KsCreateFilterFactory as well.  
//
const
KSDEVICE_DESCRIPTOR
CaptureDeviceDescriptor = {
    &CaptureDeviceDispatch,
    SIZEOF_ARRAY (FilterDescriptors),
    FilterDescriptors,
    KSDEVICE_DESCRIPTOR_VERSION
};

/**************************************************************************

    INITIALIZATION CODE

**************************************************************************/


extern "C"
NTSTATUS
DriverEntry (
    IN PDRIVER_OBJECT DriverObject,
    IN PUNICODE_STRING RegistryPath
    )

/*++

Routine Description:

    Driver entry point.  Pass off control to the AVStream initialization
    function (KsInitializeDriver) and return the status code from it.

Arguments:

    DriverObject -
        The WDM driver object for our driver

    RegistryPath -
        The registry path for our registry info

Return Value:

    As from KsInitializeDriver

--*/

{

    //
    // Simply pass the device descriptor and parameters off to AVStream
    // to initialize us.  This will cause filter factories to be set up
    // at add & start.  Everything is done based on the descriptors passed
    // here.
    //
    return 
        KsInitializeDriver (
            DriverObject,
            RegistryPath,
            &CaptureDeviceDescriptor
            );

}