windows-nt/Source/XPSP1/NT/drivers/wdm/usb/driver/bulkusb/bulkusb.htm
2020-09-26 16:20:57 +08:00

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<p><b><font face="Times New Roman">The Bulkusb driver</font></b></p>
<ul>
<li><font face="Times New Roman">The bulkusb driver is a generic function driver, based on the
Windows Driver Model (WDM).</font></li>
<li><font face="Times New Roman">Supports Plug and Play(PnP), Power
Management(PM), Windows Management Instrumentation (WMI) and the Selective
Suspend (SS) features.</font></li>
<li><font face="Times New Roman">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.</font></li>
<li>
<p><font face="Times New Roman">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. </font></p>
</li>
</ul>
<p><font face="Times New Roman">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</font></p>
<p><font face="Times New Roman">The section below describes the driver routines
that allow a user-mode application to perform bulk reads and writes.</font></p>
<p><b>Bulkusb Reads/Writes</b></p>
<table border="1" width="68%">
<tr>
<td width="50%"><font face="Courier New">Requests</font></td>
<td width="50%"><font face="Courier New">Dispatch Routines</font></td>
</tr>
<tr>
<td width="50%"><font face="Courier New">IRP_MJ_CREATE</font></td>
<td width="50%"><font face="Courier New">BulkUsb_DispatchCreate()</font></td>
</tr>
<tr>
<td width="50%"><font face="Courier New">IRP_MJ_CLOSE</font></td>
<td width="50%"><font face="Courier New">BulkUsb_DispatchClose()</font></td>
</tr>
<tr>
<td width="50%"><font face="Courier New">IRP_MJ_READ</font></td>
<td width="50%"><font face="Courier New">BulkUsb_DispatchReadWrite()</font></td>
</tr>
<tr>
<td width="50%"><font face="Courier New">IRP_MJ_WRITE</font></td>
<td width="50%"><font face="Courier New">BulkUsb_DispatchReadWrite()</font></td>
</tr>
</table>
<p>Notes</p>
<ul>
<li>The <font face="Courier New">BulkUsb_DispatchCreate</font> allows
user-mode app to open handles to the device or to a specific pipe.</li>
<li>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.</li>
<li>The <font face="Courier New">BulkUsb_DispatchClose</font> closes open handle to a specific pipe and the
device.</li>
</ul>
<p><font face="Times New Roman">The </font><font face="Courier New">BulkUsb_DispatchReadWrite</font><font face="Times New Roman">,
transforms the </font>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 (<font face="Courier New">BulkUsb_ReadWriteCompletion)</font><font face="Times New Roman">.
</font>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.</p>
<p>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.</p>
<p>Please refer the detailed inline comments in the bulkusb driver for
implementation details.</p>
<p>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.</p>
<p>&nbsp;</p>
<p>&nbsp;</p>
<p>&nbsp;</p>
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