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Merge branch 'linus' into tracing/core
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Merge reason: Pick up kernel/softirq.c update for dependent fix.

Signed-off-by: Ingo Molnar <[email protected]>
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Ingo Molnar committed Sep 17, 2009
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2 changes: 1 addition & 1 deletion CREDITS
Original file line number Diff line number Diff line change
Expand Up @@ -2800,7 +2800,7 @@ D: Starter of Linux1394 effort
S: ask per mail for current address

N: Nicolas Pitre
E: nico@cam.org
E: nico@fluxnic.net
D: StrongARM SA1100 support integrator & hacker
D: Xscale PXA architecture
D: unified SMC 91C9x/91C11x ethernet driver (smc91x)
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2 changes: 2 additions & 0 deletions Documentation/00-INDEX
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Expand Up @@ -82,6 +82,8 @@ block/
- info on the Block I/O (BIO) layer.
blockdev/
- info on block devices & drivers
btmrvl.txt
- info on Marvell Bluetooth driver usage.
cachetlb.txt
- describes the cache/TLB flushing interfaces Linux uses.
cdrom/
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10 changes: 10 additions & 0 deletions Documentation/ABI/testing/sysfs-bus-pci
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Expand Up @@ -84,6 +84,16 @@ Description:
from this part of the device tree.
Depends on CONFIG_HOTPLUG.

What: /sys/bus/pci/devices/.../reset
Date: July 2009
Contact: Michael S. Tsirkin <[email protected]>
Description:
Some devices allow an individual function to be reset
without affecting other functions in the same device.
For devices that have this support, a file named reset
will be present in sysfs. Writing 1 to this file
will perform reset.

What: /sys/bus/pci/devices/.../vpd
Date: February 2008
Contact: Ben Hutchings <[email protected]>
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163 changes: 163 additions & 0 deletions Documentation/DocBook/uio-howto.tmpl
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Expand Up @@ -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 ([email protected])</holder>
</copyright>

<legalnotice>
<para>
Expand All @@ -41,6 +45,13 @@ GPL version 2.
</abstract>

<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>
Expand Down Expand Up @@ -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>
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