1 files changed, 163 insertions, 0 deletions

diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl
index 8f6e3b2403c7..4d4ce0e61e42 100644
--- a/Documentation/DocBook/uio-howto.tmpl
+++ b/Documentation/DocBook/uio-howto.tmpl
@@ -25,6 +25,10 @@
         <year>2006-2008</year>
         <holder>Hans-Jürgen Koch.</holder>
 </copyright>
+<copyright>
+        <year>2009</year>
+        <holder>Red Hat Inc, Michael S. Tsirkin (mst@redhat.com)</holder>
+</copyright>
 
 <legalnotice>
 <para>
@@ -42,6 +46,13 @@ GPL version 2.
 
 <revhistory>
         <revision>
+        <revnumber>0.9</revnumber>
+        <date>2009-07-16</date>
+        <authorinitials>mst</authorinitials>
+        <revremark>Added generic pci driver
+                </revremark>
+        </revision>
+        <revision>
         <revnumber>0.8</revnumber>
         <date>2008-12-24</date>
         <authorinitials>hjk</authorinitials>
@@ -809,6 +820,158 @@ framework to set up sysfs files for this region. Simply leave it alone.
 
 </chapter>
 
+<chapter id="uio_pci_generic" xreflabel="Using Generic driver for PCI cards">
+<?dbhtml filename="uio_pci_generic.html"?>
+<title>Generic PCI UIO driver</title>
+        <para>
+        The generic driver is a kernel module named uio_pci_generic.
+        It can work with any device compliant to PCI 2.3 (circa 2002) and
+        any compliant PCI Express device. Using this, you only need to
+        write the userspace driver, removing the need to write
+        a hardware-specific kernel module.
+        </para>
+
+<sect1 id="uio_pci_generic_binding">
+<title>Making the driver recognize the device</title>
+        <para>
+Since the driver does not declare any device ids, 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:
+        <programlisting>
+ modprobe uio_pci_generic
+ echo &quot;8086 10f5&quot; &gt; /sys/bus/pci/drivers/uio_pci_generic/new_id
+        </programlisting>
+        </para>
+        <para>
+If there already is a hardware specific kernel driver for your 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 0000:00:19.0 &gt; /sys/bus/pci/drivers/e1000e/unbind
+    echo -n 0000:00:19.0 &gt; /sys/bus/pci/drivers/uio_pci_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/pci/devices/0000:00:19.0/driver
+        </programlisting>
+Which if successful should print
+        <programlisting>
+  .../0000:00:19.0/driver -&gt; ../../../bus/pci/drivers/uio_pci_generic
+        </programlisting>
+Note that the generic driver will not bind to old PCI 2.2 devices.
+If binding the device failed, run the following command:
+        <programlisting>
+  dmesg
+        </programlisting>
+and look in the output for failure reasons
+        </para>
+</sect1>
+
+<sect1 id="uio_pci_generic_internals">
+<title>Things to know about uio_pci_generic</title>
+        <para>
+Interrupts are handled using the Interrupt Disable bit in the PCI command
+register and Interrupt Status bit in the PCI status register.  All devices
+compliant to PCI 2.3 (circa 2002) and all compliant PCI Express devices should
+support these bits.  uio_pci_generic detects this support, and won't bind to
+devices which do not support the Interrupt Disable Bit in the command register.
+        </para>
+        <para>
+On each interrupt, uio_pci_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>
+<sect1 id="uio_pci_generic_userspace">
+<title>Writing userspace driver using uio_pci_generic</title>
+        <para>
+Userspace driver can use pci sysfs interface, or the
+libpci libray that wraps it, to talk to the device and to
+re-enable interrupts by writing to the command register.
+        </para>
+</sect1>
+<sect1 id="uio_pci_generic_example">
+<title>Example code using uio_pci_generic</title>
+        <para>
+Here is some sample userspace driver code using uio_pci_generic:
+<programlisting>
+#include &lt;stdlib.h&gt;
+#include &lt;stdio.h&gt;
+#include &lt;unistd.h&gt;
+#include &lt;sys/types.h&gt;
+#include &lt;sys/stat.h&gt;
+#include &lt;fcntl.h&gt;
+#include &lt;errno.h&gt;
+
+int main()
+{
+        int uiofd;
+        int configfd;
+        int err;
+        int i;
+        unsigned icount;
+        unsigned char command_high;
+
+        uiofd = open(&quot;/dev/uio0&quot;, O_RDONLY);
+        if (uiofd &lt; 0) {
+                perror(&quot;uio open:&quot;);
+                return errno;
+        }
+        configfd = open(&quot;/sys/class/uio/uio0/device/config&quot;, O_RDWR);
+        if (uiofd &lt; 0) {
+                perror(&quot;config open:&quot;);
+                return errno;
+        }
+
+        /* Read and cache command value */
+        err = pread(configfd, &amp;command_high, 1, 5);
+        if (err != 1) {
+                perror(&quot;command config read:&quot;);
+                return errno;
+        }
+        command_high &amp;= ~0x4;
+
+        for(i = 0;; ++i) {
+                /* Print out a message, for debugging. */
+                if (i == 0)
+                        fprintf(stderr, &quot;Started uio test driver.\n&quot;);
+                else
+                        fprintf(stderr, &quot;Interrupts: %d\n&quot;, icount);
+
+                /****************************************/
+                /* Here we got an interrupt from the
+                   device. Do something to it. */
+                /****************************************/
+
+                /* Re-enable interrupts. */
+                err = pwrite(configfd, &amp;command_high, 1, 5);
+                if (err != 1) {
+                        perror(&quot;config write:&quot;);
+                        break;
+                }
+
+                /* Wait for next interrupt. */
+                err = read(uiofd, &amp;icount, 4);
+                if (err != 4) {
+                        perror(&quot;uio read:&quot;);
+                        break;
+                }
+
+        }
+        return errno;
+}
+
+</programlisting>
+        </para>
+</sect1>
+
+</chapter>
+
 <appendix id="app1">
 <title>Further information</title>
 <itemizedlist>