Bulk Usb

The Bulkusb driver

The bulkusb driver is a generic function driver, based on the Windows Driver Model (WDM).
Supports Plug and Play(PnP), Power Management(PM), Windows Management Instrumentation (WMI) and the Selective Suspend (SS) features.
This sample is based off the selSusp DDK sample. Please refer the selSusp sample and the DDK docs to understand the handling of PnP, PM, WMI and SS features and implementations.
The USB device used for this sample is a generic Intel I82930 USB evaluation board programmed with a simple loopback test using a 64 KB circular buffer. None of the code in the sample is specific to this controller chip.

The bulkusb.sys is a minidriver that transfers asynchronous bulk data packets to and from this board. The USB Request Block (URBs) allow an abstracted chip-independent transfer to and from the core USB stack. The sample also consists of a console application

The section below describes the driver routines that allow a user-mode application to perform bulk reads and writes.

Bulkusb Reads/Writes

Requests	Dispatch Routines
IRP_MJ_CREATE	BulkUsb_DispatchCreate()
IRP_MJ_CLOSE	BulkUsb_DispatchClose()
IRP_MJ_READ	BulkUsb_DispatchReadWrite()
IRP_MJ_WRITE	BulkUsb_DispatchReadWrite()

Notes

The BulkUsb_DispatchCreate allows user-mode app to open handles to the device or to a specific pipe.
The pipe # 3 and pipe # 4 correspond to the bulk IN and bulk OUT pipes on the I82930 board respectively. The driver does not hard-code the pipe # for reads and writes.
The BulkUsb_DispatchClose closes open handle to a specific pipe and the device.

The BulkUsb_DispatchReadWrite, transforms the original read/write request into an internal device control request, creates and initializes an URB for this request and sets a completion routine for this request (BulkUsb_ReadWriteCompletion). The amount of data transferred is limited by the BULKUSB_MAX_TRANSFER_SIZE (64KB circular buffer limitation). For additional data transfers, the request (Irp/Urb pair) is re-initialized and re-submitted in the completion routine.

Since the driver does not save the read-write context information anywhere in the driver, but passes it along to the completion routine, it is multi-threaded safe.

Please refer the detailed inline comments in the bulkusb driver for implementation details.

The rwbulk.exe console application is used to initiate bulk transfers and obtain a dump of information on the device's I/O endpoints. The application also demonstrates how to use GUID-based device names and pipe names generated by the operating system using the SetupDiXXX user-mode APIs.