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Commit a164a8a6 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by Jonathan Corbet
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doc: add documentation for uio-hv-generic 



Update UIO documentation to include basic information about
uio_hv_generic.

Signed-off-by: default avatarStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 5ac9baf4

Documentation/DocBook/uio-howto.tmpl

+62 −0
Original line number Diff line number Diff line
@@ -45,6 +45,13 @@ GPL version 2. 
</abstract>



<revhistory>

	<revision>

	<revnumber>0.10</revnumber>

	<date>2016-10-17</date>

	<authorinitials>sch</authorinitials>

	<revremark>Added generic hyperv driver

		</revremark>

	</revision>

	<revision>

	<revnumber>0.9</revnumber>

	<date>2009-07-16</date>
@@ -1033,6 +1040,61 @@ int main() 


</chapter>



<chapter id="uio_hv_generic" xreflabel="Using Generic driver for Hyper-V VMBUS">

<?dbhtml filename="uio_hv_generic.html"?>

<title>Generic Hyper-V UIO driver</title>

	<para>

	The generic driver is a kernel module named uio_hv_generic.

	It supports devices on the Hyper-V VMBus similar to uio_pci_generic

	on PCI bus.

	</para>



<sect1 id="uio_hv_generic_binding">

<title>Making the driver recognize the device</title>

	<para>

Since the driver does not declare any device GUID's, it will not get loaded

automatically and will not automatically bind to any devices, you must load it

and allocate id to the driver yourself. For example, to use the network device

GUID:

	<programlisting>

 modprobe uio_hv_generic

 echo &quot;f8615163-df3e-46c5-913f-f2d2f965ed0e&quot; &gt; /sys/bus/vmbus/drivers/uio_hv_generic/new_id

	</programlisting>

	</para>

	<para>

If there already is a hardware specific kernel driver for the device, the

generic driver still won't bind to it, in this case if you want to use the

generic driver (why would you?) you'll have to manually unbind the hardware

specific driver and bind the generic driver, like this:

	<programlisting>

	  echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 &gt; /sys/bus/vmbus/drivers/hv_netvsc/unbind

	  echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 &gt; /sys/bus/vmbus/drivers/uio_hv_generic/bind

	</programlisting>

	</para>

	<para>

You can verify that the device has been bound to the driver

by looking for it in sysfs, for example like the following:

	<programlisting>

    ls -l /sys/bus/vmbus/devices/vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3/driver

	</programlisting>

Which if successful should print

	<programlisting>

  .../vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3/driver -&gt; ../../../bus/vmbus/drivers/uio_hv_generic

	</programlisting>

	</para>

</sect1>



<sect1 id="uio_hv_generic_internals">

<title>Things to know about uio_hv_generic</title>

	<para>

On each interrupt, uio_hv_generic sets the Interrupt Disable bit.

This prevents the device from generating further interrupts

until the bit is cleared. The userspace driver should clear this

bit before blocking and waiting for more interrupts.

	</para>

</sect1>

</chapter>



<appendix id="app1">

<title>Further information</title>

<itemizedlist>