pnpdma.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

/* $Id: pnpdma.c 22747 2006-07-01 21:51:06Z ion $
 *
 * COPYRIGHT:       See COPYING in the top level directory
 * PROJECT:         ReactOS kernel
 * FILE:            ntoskrnl/io/pnpdma.c
 * PURPOSE:         PnP manager DMA routines
 *
 * PROGRAMMERS:     Filip Navara ([e-mail])
 */

/* INCLUDES ******************************************************************/

#include <ntoskrnl.h>
#define NDEBUG
#include <internal/debug.h>
#include <wdmguid.h>

/* FUNCTIONS *****************************************************************/

/*
 * @implemented
 */
PDMA_ADAPTER STDCALL
IoGetDmaAdapter(
  IN PDEVICE_OBJECT PhysicalDeviceObject,
  IN PDEVICE_DESCRIPTION DeviceDescription,
  IN OUT PULONG NumberOfMapRegisters)
{
  NTSTATUS Status;
  ULONG ResultLength;
  BUS_INTERFACE_STANDARD BusInterface;
  IO_STATUS_BLOCK IoStatusBlock;
  IO_STACK_LOCATION Stack;
  DEVICE_DESCRIPTION PrivateDeviceDescription;
  PDMA_ADAPTER Adapter = NULL;

  DPRINT("IoGetDmaAdapter called\n");

  /*
   * Try to create DMA adapter through bus driver.
   */

  if (PhysicalDeviceObject != NULL)
  {
    if (DeviceDescription->InterfaceType == PNPBus ||
        DeviceDescription->InterfaceType == InterfaceTypeUndefined)
    {
      RtlCopyMemory(&PrivateDeviceDescription, DeviceDescription,
        sizeof(DEVICE_DESCRIPTION));
      Status = IoGetDeviceProperty(PhysicalDeviceObject,
         DevicePropertyLegacyBusType, sizeof(INTERFACE_TYPE),
         &PrivateDeviceDescription.InterfaceType, &ResultLength);
      if (!NT_SUCCESS(Status))
        PrivateDeviceDescription.InterfaceType = Internal;
      DeviceDescription = &PrivateDeviceDescription;
    }

    Stack.Parameters.QueryInterface.Size = sizeof(BUS_INTERFACE_STANDARD);
    Stack.Parameters.QueryInterface.Version = 1;
    Stack.Parameters.QueryInterface.Interface = (PINTERFACE)&BusInterface;
    Stack.Parameters.QueryInterface.InterfaceType =
      &GUID_BUS_INTERFACE_STANDARD;
    Status = IopInitiatePnpIrp(PhysicalDeviceObject, &IoStatusBlock,
      IRP_MN_QUERY_INTERFACE, &Stack);
    if (NT_SUCCESS(Status))
    {
      Adapter = BusInterface.GetDmaAdapter(BusInterface.Context,
        DeviceDescription, NumberOfMapRegisters);
      BusInterface.InterfaceDereference(BusInterface.Context);
      if (Adapter != NULL)
        return Adapter;
    }
  }

  /*
   * Fallback to HAL.
   */

  return HalGetDmaAdapter(PhysicalDeviceObject, DeviceDescription,
                          NumberOfMapRegisters);
}

/* EOF */