[PATCH v2 3/3] doc: add documentation for uio-hv-generic

From: Stephen Hemminger
Date: Mon Oct 17 2016 - 15:33:28 EST

From: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>

Update UIO documentation to include basic information about

Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Documentation/DocBook/uio-howto.tmpl | 62 ++++++++++++++++++++++++++++++++++++
1 file changed, 62 insertions(+)

diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl
index cd0e452..5210f8a 100644
--- a/Documentation/DocBook/uio-howto.tmpl
+++ b/Documentation/DocBook/uio-howto.tmpl
@@ -46,6 +46,13 @@ GPL version 2.

+ <revnumber>0.10</revnumber>
+ <date>2016-10-17</date>
+ <authorinitials>sch</authorinitials>
+ <revremark>Added generic hyperv driver
+ </revremark>
+ </revision>
+ <revision>
@@ -1033,6 +1040,61 @@ int main()


+<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
+ <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 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>
<appendix id="app1">
<title>Further information</title>