Windows Driver Development-5

In the previous article "Windows Driver Development-4" We have completed the hardware preparation. However, we do not have specific data operations, such as receiving read and write operations.

The IO control of the device is required prior to such operations in WDF, and the integrity of the data is maintained.

We know that the development of WDF is mainly followed by the "Footsteps" of IRPs.

I/O Request Delivery mechanism
I/O request type	UMDF delivery mechanism	KMDF delivery mechanism
read	queue	queue
write	queue	queue
device I/O control	queue	queue
internal device I/O control	queue	queue
create	queue	queue or callback
close	callback	callback
Cleanup	Callback	Callback

As you can see from the table, WDF is a mechanism for using queue (queue) when making device I/O control.

So, we're going to provide queue support when adding devices.

  Wdf_object_attributes_init_context_type (&ioqueueconfig,                                    wdfioqueuedispatchparallel);    Ioqueueconfig.evtiodevicecontrol = Evtiodevicecontrol;    Status = Wdfioqueuecreate (device,                         &ioqueueconfig,                         wdf_no_object_attributes,                         wdf_no_handle);

(1) Initialize the queue configuration

Wdf_io_queue_config_init_default_queue

VOID wdf_io_queue_config_init_default_queue (  _out_ pwdf_io_queue_config       CONFIG,  _in_  Wdf_io_ Queue_dispatch_type Dispatchtype);

(2) Setting callback events

Sets the value of a member variable in the WDF_IO_QUEUE_CONFIG structure.

typedef struct _WDF_IO_QUEUE_CONFIG {ULONG Size;  Wdf_io_queue_dispatch_type Dispatchtype;  Wdf_tri_state powermanaged;  BOOLEAN allowzerolengthrequests;  BOOLEAN Defaultqueue;  Pfn_wdf_io_queue_io_default Evtiodefault;  Pfn_wdf_io_queue_io_read Evtioread;  Pfn_wdf_io_queue_io_write Evtiowrite;  Pfn_wdf_io_queue_io_device_control Evtiodevicecontrol;  Pfn_wdf_io_queue_io_internal_device_control Evtiointernaldevicecontrol;  Pfn_wdf_io_queue_io_stop Evtiostop;  Pfn_wdf_io_queue_io_resume Evtioresume;  Pfn_wdf_io_queue_io_canceled_on_queue Evtiocanceledonqueue;    Union {struct {ULONG numberofpresentedrequests;  } Parallel;  } Settings; Wdfdriver Driver;} Wdf_io_queue_config, *pwdf_io_quEue_config; 

(3) Set up a queue
Wdfioqueuecreate

NTSTATUS wdfioqueuecreate (  [in]            wdfdevice              Device,  [in]            pwdf_io_queue_config   CONFIG,  [in, optional]  Pwdf_object_attributes queueattributes,  [out, optional] wdfqueue               *queue);

Windows Driver Development-5