doc: convert UIO howto from docbook to sphinx

Converted with tmplcvt. Only some tiny things needed manual fixing.

Signed-off-by: Alexander Dahl <post@lespocky.de>
Cc: Hans-Jürgen Koch <hjk@hansjkoch.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 1 insertions, 1113 deletions

diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile
index a6eb7dcd4dd5..5fd8f5effd0c 100644
--- a/Documentation/DocBook/Makefile
+++ b/Documentation/DocBook/Makefile
@@ -11,7 +11,7 @@ DOCBOOKS := z8530book.xml  \
 	    writing_usb_driver.xml networking.xml \
 	    kernel-api.xml filesystems.xml lsm.xml kgdb.xml \
 	    gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \
-	    genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \
+	    genericirq.xml s390-drivers.xml scsi.xml \
 	    sh.xml regulator.xml w1.xml \
 	    writing_musb_glue_layer.xml iio.xml
 
diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl
deleted file mode 100644
index 5210f8a577c6..000000000000
--- a/Documentation/DocBook/uio-howto.tmpl
+++ /dev/null
@@ -1,1112 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
-"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" []>
-
-<book id="index">
-<bookinfo>
-<title>The Userspace I/O HOWTO</title>
-
-<author>
-      <firstname>Hans-Jürgen</firstname>
-      <surname>Koch</surname>
-      <authorblurb><para>Linux developer, Linutronix</para></authorblurb>
-	<affiliation>
-	<orgname>
-		<ulink url="http://www.linutronix.de">Linutronix</ulink>
-	</orgname>
-
-	<address>
-	   <email>hjk@hansjkoch.de</email>
-	</address>
-    </affiliation>
-</author>
-
-<copyright>
-	<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>
-This documentation is Free Software licensed under the terms of the
-GPL version 2.
-</para>
-</legalnotice>
-
-<pubdate>2006-12-11</pubdate>
-
-<abstract>
-	<para>This HOWTO describes concept and usage of Linux kernel's
-		Userspace I/O system.</para>
-</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>
-	<authorinitials>mst</authorinitials>
-	<revremark>Added generic pci driver
-		</revremark>
-	</revision>
-	<revision>
-	<revnumber>0.8</revnumber>
-	<date>2008-12-24</date>
-	<authorinitials>hjk</authorinitials>
-	<revremark>Added name attributes in mem and portio sysfs directories.
-		</revremark>
-	</revision>
-	<revision>
-	<revnumber>0.7</revnumber>
-	<date>2008-12-23</date>
-	<authorinitials>hjk</authorinitials>
-	<revremark>Added generic platform drivers and offset attribute.</revremark>
-	</revision>
-	<revision>
-	<revnumber>0.6</revnumber>
-	<date>2008-12-05</date>
-	<authorinitials>hjk</authorinitials>
-	<revremark>Added description of portio sysfs attributes.</revremark>
-	</revision>
-	<revision>
-	<revnumber>0.5</revnumber>
-	<date>2008-05-22</date>
-	<authorinitials>hjk</authorinitials>
-	<revremark>Added description of write() function.</revremark>
-	</revision>
-	<revision>
-	<revnumber>0.4</revnumber>
-	<date>2007-11-26</date>
-	<authorinitials>hjk</authorinitials>
-	<revremark>Removed section about uio_dummy.</revremark>
-	</revision>
-	<revision>
-	<revnumber>0.3</revnumber>
-	<date>2007-04-29</date>
-	<authorinitials>hjk</authorinitials>
-	<revremark>Added section about userspace drivers.</revremark>
-	</revision>
-	<revision>
-	<revnumber>0.2</revnumber>
-	<date>2007-02-13</date>
-	<authorinitials>hjk</authorinitials>
-	<revremark>Update after multiple mappings were added.</revremark>
-	</revision>
-	<revision>
-	<revnumber>0.1</revnumber>
-	<date>2006-12-11</date>
-	<authorinitials>hjk</authorinitials>
-	<revremark>First draft.</revremark>
-	</revision>
-</revhistory>
-</bookinfo>
-
-<chapter id="aboutthisdoc">
-<?dbhtml filename="aboutthis.html"?>
-<title>About this document</title>
-
-<sect1 id="translations">
-<?dbhtml filename="translations.html"?>
-<title>Translations</title>
-
-<para>If you know of any translations for this document, or you are
-interested in translating it, please email me
-<email>hjk@hansjkoch.de</email>.
-</para>
-</sect1>
-
-<sect1 id="preface">
-<title>Preface</title>
-	<para>
-	For many types of devices, creating a Linux kernel driver is
-	overkill.  All that is really needed is some way to handle an
-	interrupt and provide access to the memory space of the
-	device.  The logic of controlling the device does not
-	necessarily have to be within the kernel, as the device does
-	not need to take advantage of any of other resources that the
-	kernel provides.  One such common class of devices that are
-	like this are for industrial I/O cards.
-	</para>
-	<para>
-	To address this situation, the userspace I/O system (UIO) was
-	designed.  For typical industrial I/O cards, only a very small
-	kernel module is needed. The main part of the driver will run in
-	user space. This simplifies development and reduces the risk of
-	serious bugs within a kernel module.
-	</para>
-	<para>
-	Please note that UIO is not an universal driver interface. Devices
-	that are already handled well by other kernel subsystems (like
-	networking or serial or USB) are no candidates for an UIO driver.
-	Hardware that is ideally suited for an UIO driver fulfills all of
-	the following:
-	</para>
-<itemizedlist>
-<listitem>
-	<para>The device has memory that can be mapped. The device can be
-	controlled completely by writing to this memory.</para>
-</listitem>
-<listitem>
-	<para>The device usually generates interrupts.</para>
-</listitem>
-<listitem>
-	<para>The device does not fit into one of the standard kernel
-	subsystems.</para>
-</listitem>
-</itemizedlist>
-</sect1>
-
-<sect1 id="thanks">
-<title>Acknowledgments</title>
-	<para>I'd like to thank Thomas Gleixner and Benedikt Spranger of
-	Linutronix, who have not only written most of the UIO code, but also
-	helped greatly writing this HOWTO by giving me all kinds of background
-	information.</para>
-</sect1>
-
-<sect1 id="feedback">
-<title>Feedback</title>
-	<para>Find something wrong with this document? (Or perhaps something
-	right?) I would love to hear from you. Please email me at
-	<email>hjk@hansjkoch.de</email>.</para>
-</sect1>
-</chapter>
-
-<chapter id="about">
-<?dbhtml filename="about.html"?>
-<title>About UIO</title>
-
-<para>If you use UIO for your card's driver, here's what you get:</para>
-
-<itemizedlist>
-<listitem>
-	<para>only one small kernel module to write and maintain.</para>
-</listitem>
-<listitem>
-	<para>develop the main part of your driver in user space,
-	with all the tools and libraries you're used to.</para>
-</listitem>
-<listitem>
-	<para>bugs in your driver won't crash the kernel.</para>
-</listitem>
-<listitem>
-	<para>updates of your driver can take place without recompiling
-	the kernel.</para>
-</listitem>
-</itemizedlist>
-
-<sect1 id="how_uio_works">
-<title>How UIO works</title>
-	<para>
-	Each UIO device is accessed through a device file and several
-	sysfs attribute files. The device file will be called
-	<filename>/dev/uio0</filename> for the first device, and
-	<filename>/dev/uio1</filename>, <filename>/dev/uio2</filename>
-	and so on for subsequent devices.
-	</para>
-
-	<para><filename>/dev/uioX</filename> is used to access the
-	address space of the card. Just use
-	<function>mmap()</function> to access registers or RAM
-	locations of your card.
-	</para>
-
-	<para>
-	Interrupts are handled by reading from
-	<filename>/dev/uioX</filename>. A blocking
-	<function>read()</function> from
-	<filename>/dev/uioX</filename> will return as soon as an
-	interrupt occurs. You can also use
-	<function>select()</function> on
-	<filename>/dev/uioX</filename> to wait for an interrupt. The
-	integer value read from <filename>/dev/uioX</filename>
-	represents the total interrupt count. You can use this number
-	to figure out if you missed some interrupts.
-	</para>
-	<para>
-	For some hardware that has more than one interrupt source internally,
-	but not separate IRQ mask and status registers, there might be
-	situations where userspace cannot determine what the interrupt source
-	was if the kernel handler disables them by writing to the chip's IRQ
-	register. In such a case, the kernel has to disable the IRQ completely
-	to leave the chip's register untouched. Now the userspace part can
-	determine the cause of the interrupt, but it cannot re-enable
-	interrupts. Another cornercase is chips where re-enabling interrupts
-	is a read-modify-write operation to a combined IRQ status/acknowledge
-	register. This would be racy if a new interrupt occurred
-	simultaneously.
-	</para>
-	<para>
-	To address these problems, UIO also implements a write() function. It
-	is normally not used and can be ignored for hardware that has only a
-	single interrupt source or has separate IRQ mask and status registers.
-	If you need it, however, a write to <filename>/dev/uioX</filename>
-	will call the <function>irqcontrol()</function> function implemented
-	by the driver. You have to write a 32-bit value that is usually either
-	0 or 1 to disable or enable interrupts. If a driver does not implement
-	<function>irqcontrol()</function>, <function>write()</function> will
-	return with <varname>-ENOSYS</varname>.
-	</para>
-
-	<para>
-	To handle interrupts properly, your custom kernel module can
-	provide its own interrupt handler. It will automatically be
-	called by the built-in handler.
-	</para>
-
-	<para>
-	For cards that don't generate interrupts but need to be
-	polled, there is the possibility to set up a timer that
-	triggers the interrupt handler at configurable time intervals.
-	This interrupt simulation is done by calling
-	<function>uio_event_notify()</function>
-	from the timer's event handler.
-	</para>
-
-	<para>
-	Each driver provides attributes that are used to read or write
-	variables. These attributes are accessible through sysfs
-	files.  A custom kernel driver module can add its own
-	attributes to the device owned by the uio driver, but not added
-	to the UIO device itself at this time.  This might change in the
-	future if it would be found to be useful.
-	</para>
-
-	<para>
-	The following standard attributes are provided by the UIO
-	framework:
-	</para>
-<itemizedlist>
-<listitem>
-	<para>
-	<filename>name</filename>: The name of your device. It is
-	recommended to use the name of your kernel module for this.
-	</para>
-</listitem>
-<listitem>
-	<para>
-	<filename>version</filename>: A version string defined by your
-	driver. This allows the user space part of your driver to deal
-	with different versions of the kernel module.
-	</para>
-</listitem>
-<listitem>
-	<para>
-	<filename>event</filename>: The total number of interrupts
-	handled by the driver since the last time the device node was
-	read.
-	</para>
-</listitem>
-</itemizedlist>
-<para>
-	These attributes appear under the
-	<filename>/sys/class/uio/uioX</filename> directory.  Please
-	note that this directory might be a symlink, and not a real
-	directory.  Any userspace code that accesses it must be able
-	to handle this.
-</para>
-<para>
-	Each UIO device can make one or more memory regions available for
-	memory mapping. This is necessary because some industrial I/O cards
-	require access to more than one PCI memory region in a driver.
-</para>
-<para>
-	Each mapping has its own directory in sysfs, the first mapping
-	appears as <filename>/sys/class/uio/uioX/maps/map0/</filename>.
-	Subsequent mappings create directories <filename>map1/</filename>,
-	<filename>map2/</filename>, and so on. These directories will only
-	appear if the size of the mapping is not 0.
-</para>
-<para>
-	Each <filename>mapX/</filename> directory contains four read-only files
-	that show attributes of the memory:
-</para>
-<itemizedlist>
-<listitem>
-	<para>
-	<filename>name</filename>: A string identifier for this mapping. This
-	is optional, the string can be empty. Drivers can set this to make it
-	easier for userspace to find the correct mapping.
-	</para>
-</listitem>
-<listitem>
-	<para>
-	<filename>addr</filename>: The address of memory that can be mapped.
-	</para>
-</listitem>
-<listitem>
-	<para>
-	<filename>size</filename>: The size, in bytes, of the memory
-	pointed to by addr.
-	</para>
-</listitem>
-<listitem>
-	<para>
-	<filename>offset</filename>: The offset, in bytes, that has to be
-	added to the pointer returned by <function>mmap()</function> to get
-	to the actual device memory. This is important if the device's memory
-	is not page aligned. Remember that pointers returned by
-	<function>mmap()</function> are always page aligned, so it is good
-	style to always add this offset.
-	</para>
-</listitem>
-</itemizedlist>
-
-<para>
-	From userspace, the different mappings are distinguished by adjusting
-	the <varname>offset</varname> parameter of the
-	<function>mmap()</function> call. To map the memory of mapping N, you
-	have to use N times the page size as your offset:
-</para>
-<programlisting format="linespecific">
-offset = N * getpagesize();
-</programlisting>
-
-<para>
-	Sometimes there is hardware with memory-like regions that can not be
-	mapped with the technique described here, but there are still ways to
-	access them from userspace. The most common example are x86 ioports.
-	On x86 systems, userspace can access these ioports using
-	<function>ioperm()</function>, <function>iopl()</function>,
-	<function>inb()</function>, <function>outb()</function>, and similar
-	functions.
-</para>
-<para>
-	Since these ioport regions can not be mapped, they will not appear under
-	<filename>/sys/class/uio/uioX/maps/</filename> like the normal memory
-	described above. Without information about the port regions a hardware
-	has to offer, it becomes difficult for the userspace part of the
-	driver to find out which ports belong to which UIO device.
-</para>
-<para>
-	To address this situation, the new directory
-	<filename>/sys/class/uio/uioX/portio/</filename> was added. It only
-	exists if the driver wants to pass information about one or more port
-	regions to userspace. If that is the case, subdirectories named
-	<filename>port0</filename>, <filename>port1</filename>, and so on,
-	will appear underneath
-	<filename>/sys/class/uio/uioX/portio/</filename>.
-</para>
-<para>
-	Each <filename>portX/</filename> directory contains four read-only
-	files that show name, start, size, and type of the port region:
-</para>
-<itemizedlist>
-<listitem>
-	<para>
-	<filename>name</filename>: A string identifier for this port region.
-	The string is optional and can be empty. Drivers can set it to make it
-	easier for userspace to find a certain port region.
-	</para>
-</listitem>
-<listitem>
-	<para>
-	<filename>start</filename>: The first port of this region.
-	</para>
-</listitem>
-<listitem>
-	<para>
-	<filename>size</filename>: The number of ports in this region.
-	</para>
-</listitem>
-<listitem>
-	<para>
-	<filename>porttype</filename>: A string describing the type of port.
-	</para>
-</listitem>
-</itemizedlist>
-
-
-</sect1>
-</chapter>
-
-<chapter id="custom_kernel_module" xreflabel="Writing your own kernel module">
-<?dbhtml filename="custom_kernel_module.html"?>
-<title>Writing your own kernel module</title>
-	<para>
-	Please have a look at <filename>uio_cif.c</filename> as an
-	example. The following paragraphs explain the different
-	sections of this file.
-	</para>
-
-<sect1 id="uio_info">
-<title>struct uio_info</title>
-	<para>
-	This structure tells the framework the details of your driver,
-	Some of the members are required, others are optional.
-	</para>
-
-<itemizedlist>
-<listitem><para>
-<varname>const char *name</varname>: Required. The name of your driver as
-it will appear in sysfs. I recommend using the name of your module for this.
-</para></listitem>
-
-<listitem><para>
-<varname>const char *version</varname>: Required. This string appears in
-<filename>/sys/class/uio/uioX/version</filename>.
-</para></listitem>
-
-<listitem><para>
-<varname>struct uio_mem mem[ MAX_UIO_MAPS ]</varname>: Required if you
-have memory that can be mapped with <function>mmap()</function>. For each
-mapping you need to fill one of the <varname>uio_mem</varname> structures.
-See the description below for details.
-</para></listitem>
-
-<listitem><para>
-<varname>struct uio_port port[ MAX_UIO_PORTS_REGIONS ]</varname>: Required
-if you want to pass information about ioports to userspace. For each port
-region you need to fill one of the <varname>uio_port</varname> structures.
-See the description below for details.
-</para></listitem>
-
-<listitem><para>
-<varname>long irq</varname>: Required. If your hardware generates an
-interrupt, it's your modules task to determine the irq number during
-initialization. If you don't have a hardware generated interrupt but
-want to trigger the interrupt handler in some other way, set
-<varname>irq</varname> to <varname>UIO_IRQ_CUSTOM</varname>.
-If you had no interrupt at all, you could set
-<varname>irq</varname> to <varname>UIO_IRQ_NONE</varname>, though this
-rarely makes sense.
-</para></listitem>
-
-<listitem><para>
-<varname>unsigned long irq_flags</varname>: Required if you've set
-<varname>irq</varname> to a hardware interrupt number. The flags given
-here will be used in the call to <function>request_irq()</function>.
-</para></listitem>
-
-<listitem><para>
-<varname>int (*mmap)(struct uio_info *info, struct vm_area_struct
-*vma)</varname>: Optional. If you need a special
-<function>mmap()</function> function, you can set it here. If this
-pointer is not NULL, your <function>mmap()</function> will be called
-instead of the built-in one.
-</para></listitem>
-
-<listitem><para>
-<varname>int (*open)(struct uio_info *info, struct inode *inode)
-</varname>: Optional. You might want to have your own
-<function>open()</function>, e.g. to enable interrupts only when your
-device is actually used.
-</para></listitem>
-
-<listitem><para>
-<varname>int (*release)(struct uio_info *info, struct inode *inode)
-</varname>: Optional. If you define your own
-<function>open()</function>, you will probably also want a custom
-<function>release()</function> function.
-</para></listitem>
-
-<listitem><para>
-<varname>int (*irqcontrol)(struct uio_info *info, s32 irq_on)
-</varname>: Optional. If you need to be able to enable or disable
-interrupts from userspace by writing to <filename>/dev/uioX</filename>,
-you can implement this function. The parameter <varname>irq_on</varname>
-will be 0 to disable interrupts and 1 to enable them.
-</para></listitem>
-</itemizedlist>
-
-<para>
-Usually, your device will have one or more memory regions that can be mapped
-to user space. For each region, you have to set up a
-<varname>struct uio_mem</varname> in the <varname>mem[]</varname> array.
-Here's a description of the fields of <varname>struct uio_mem</varname>:
-</para>
-
-<itemizedlist>
-<listitem><para>
-<varname>const char *name</varname>: Optional. Set this to help identify
-the memory region, it will show up in the corresponding sysfs node.
-</para></listitem>
-
-<listitem><para>
-<varname>int memtype</varname>: Required if the mapping is used. Set this to
-<varname>UIO_MEM_PHYS</varname> if you you have physical memory on your
-card to be mapped. Use <varname>UIO_MEM_LOGICAL</varname> for logical
-memory (e.g. allocated with <function>kmalloc()</function>). There's also
-<varname>UIO_MEM_VIRTUAL</varname> for virtual memory.
-</para></listitem>
-
-<listitem><para>
-<varname>phys_addr_t addr</varname>: Required if the mapping is used.
-Fill in the address of your memory block. This address is the one that
-appears in sysfs.
-</para></listitem>
-
-<listitem><para>
-<varname>resource_size_t size</varname>: Fill in the size of the
-memory block that <varname>addr</varname> points to. If <varname>size</varname>
-is zero, the mapping is considered unused. Note that you
-<emphasis>must</emphasis> initialize <varname>size</varname> with zero for
-all unused mappings.
-</para></listitem>
-
-<listitem><para>
-<varname>void *internal_addr</varname>: If you have to access this memory
-region from within your kernel module, you will want to map it internally by
-using something like <function>ioremap()</function>. Addresses
-returned by this function cannot be mapped to user space, so you must not
-store it in <varname>addr</varname>. Use <varname>internal_addr</varname>
-instead to remember such an address.
-</para></listitem>
-</itemizedlist>
-
-<para>
-Please do not touch the <varname>map</varname> element of
-<varname>struct uio_mem</varname>! It is used by the UIO framework
-to set up sysfs files for this mapping. Simply leave it alone.
-</para>
-
-<para>
-Sometimes, your device can have one or more port regions which can not be
-mapped to userspace. But if there are other possibilities for userspace to
-access these ports, it makes sense to make information about the ports
-available in sysfs. For each region, you have to set up a
-<varname>struct uio_port</varname> in the <varname>port[]</varname> array.
-Here's a description of the fields of <varname>struct uio_port</varname>:
-</para>
-
-<itemizedlist>
-<listitem><para>
-<varname>char *porttype</varname>: Required. Set this to one of the predefined
-constants. Use <varname>UIO_PORT_X86</varname> for the ioports found in x86
-architectures.
-</para></listitem>
-
-<listitem><para>
-<varname>unsigned long start</varname>: Required if the port region is used.
-Fill in the number of the first port of this region.
-</para></listitem>
-
-<listitem><para>
-<varname>unsigned long size</varname>: Fill in the number of ports in this
-region. If <varname>size</varname> is zero, the region is considered unused.
-Note that you <emphasis>must</emphasis> initialize <varname>size</varname>
-with zero for all unused regions.
-</para></listitem>
-</itemizedlist>
-
-<para>
-Please do not touch the <varname>portio</varname> element of
-<varname>struct uio_port</varname>! It is used internally by the UIO
-framework to set up sysfs files for this region. Simply leave it alone.
-</para>
-
-</sect1>
-
-<sect1 id="adding_irq_handler">
-<title>Adding an interrupt handler</title>
-	<para>
-	What you need to do in your interrupt handler depends on your
-	hardware and on how you want to	handle it. You should try to
-	keep the amount of code in your kernel interrupt handler low.
-	If your hardware requires no action that you
-	<emphasis>have</emphasis> to perform after each interrupt,
-	then your handler can be empty.</para> <para>If, on the other
-	hand, your hardware <emphasis>needs</emphasis> some action to
-	be performed after each interrupt, then you
-	<emphasis>must</emphasis> do it in your kernel module. Note
-	that you cannot rely on the userspace part of your driver. Your
-	userspace program can terminate at any time, possibly leaving
-	your hardware in a state where proper interrupt handling is
-	still required.
-	</para>
-
-	<para>
-	There might also be applications where you want to read data
-	from your hardware at each interrupt and buffer it in a piece
-	of kernel memory you've allocated for that purpose.  With this
-	technique you could avoid loss of data if your userspace
-	program misses an interrupt.
-	</para>
-
-	<para>
-	A note on shared interrupts: Your driver should support
-	interrupt sharing whenever this is possible. It is possible if
-	and only if your driver can detect whether your hardware has
-	triggered the interrupt or not. This is usually done by looking
-	at an interrupt status register. If your driver sees that the
-	IRQ bit is actually set, it will perform its actions, and the
-	handler returns IRQ_HANDLED. If the driver detects that it was
-	not your hardware that caused the interrupt, it will do nothing
-	and return IRQ_NONE, allowing the kernel to call the next
-	possible interrupt handler.
-	</para>
-
-	<para>
-	If you decide not to support shared interrupts, your card
-	won't work in computers with no free interrupts. As this
-	frequently happens on the PC platform, you can save yourself a
-	lot of trouble by supporting interrupt sharing.
-	</para>
-</sect1>
-
-<sect1 id="using_uio_pdrv">
-<title>Using uio_pdrv for platform devices</title>
-	<para>
-	In many cases, UIO drivers for platform devices can be handled in a
-	generic way. In the same place where you define your
-	<varname>struct platform_device</varname>, you simply also implement
-	your interrupt handler and fill your
-	<varname>struct uio_info</varname>. A pointer to this
-	<varname>struct uio_info</varname> is then used as
-	<varname>platform_data</varname> for your platform device.
-	</para>
-	<para>
-	You also need to set up an array of <varname>struct resource</varname>
-	containing addresses and sizes of your memory mappings. This
-	information is passed to the driver using the
-	<varname>.resource</varname> and <varname>.num_resources</varname>
-	elements of <varname>struct platform_device</varname>.
-	</para>
-	<para>
-	You now have to set the <varname>.name</varname> element of
-	<varname>struct platform_device</varname> to
-	<varname>"uio_pdrv"</varname> to use the generic UIO platform device
-	driver. This driver will fill the <varname>mem[]</varname> array
-	according to the resources given, and register the device.
-	</para>
-	<para>
-	The advantage of this approach is that you only have to edit a file
-	you need to edit anyway. You do not have to create an extra driver.
-	</para>
-</sect1>
-
-<sect1 id="using_uio_pdrv_genirq">
-<title>Using uio_pdrv_genirq for platform devices</title>
-	<para>
-	Especially in embedded devices, you frequently find chips where the
-	irq pin is tied to its own dedicated interrupt line. In such cases,
-	where you can be really sure the interrupt is not shared, we can take
-	the concept of <varname>uio_pdrv</varname> one step further and use a
-	generic interrupt handler. That's what
-	<varname>uio_pdrv_genirq</varname> does.
-	</para>
-	<para>
-	The setup for this driver is the same as described above for
-	<varname>uio_pdrv</varname>, except that you do not implement an
-	interrupt handler. The <varname>.handler</varname> element of
-	<varname>struct uio_info</varname> must remain
-	<varname>NULL</varname>. The  <varname>.irq_flags</varname> element
-	must not contain <varname>IRQF_SHARED</varname>.
-	</para>
-	<para>
-	You will set the <varname>.name</varname> element of
-	<varname>struct platform_device</varname> to
-	<varname>"uio_pdrv_genirq"</varname> to use this driver.
-	</para>
-	<para>
-	The generic interrupt handler of <varname>uio_pdrv_genirq</varname>
-	will simply disable the interrupt line using
-	<function>disable_irq_nosync()</function>. After doing its work,
-	userspace can reenable the interrupt by writing 0x00000001 to the UIO
-	device file. The driver already implements an
-	<function>irq_control()</function> to make this possible, you must not
-	implement your own.
-	</para>
-	<para>
-	Using <varname>uio_pdrv_genirq</varname> not only saves a few lines of
-	interrupt handler code. You also do not need to know anything about
-	the chip's internal registers to create the kernel part of the driver.
-	All you need to know is the irq number of the pin the chip is
-	connected to.
-	</para>
-</sect1>
-
-<sect1 id="using-uio_dmem_genirq">
-<title>Using uio_dmem_genirq for platform devices</title>
-	<para>
-	In addition to statically allocated memory ranges, they may also be
-	a desire to use dynamically allocated regions in a user space driver.
-	In particular, being able to access memory made available through the
-	dma-mapping API, may be particularly useful.  The
-	<varname>uio_dmem_genirq</varname> driver provides a way to accomplish
-	this.
-	</para>
-	<para>
-	This driver is used in a similar manner to the
-	<varname>"uio_pdrv_genirq"</varname> driver with respect to interrupt
-	configuration and handling.
-	</para>
-	<para>
-	Set the <varname>.name</varname> element of
-	<varname>struct platform_device</varname> to
-	<varname>"uio_dmem_genirq"</varname> to use this driver.
-	</para>
-	<para>
-	When using this driver, fill in the <varname>.platform_data</varname>
-	element of <varname>struct platform_device</varname>, which is of type
-	<varname>struct uio_dmem_genirq_pdata</varname> and which contains the
-	following elements:
-	</para>
-	<itemizedlist>
-	<listitem><para><varname>struct uio_info uioinfo</varname>: The same
-	structure used as the  <varname>uio_pdrv_genirq</varname> platform
-	data</para></listitem>
-	<listitem><para><varname>unsigned int *dynamic_region_sizes</varname>:
-	Pointer to list of sizes of dynamic memory regions to be mapped into
-	user space.
-	</para></listitem>
-	<listitem><para><varname>unsigned int num_dynamic_regions</varname>:
-	Number of elements in <varname>dynamic_region_sizes</varname> array.
-	</para></listitem>
-	</itemizedlist>
-	<para>
-	The dynamic regions defined in the platform data will be appended to
-	the <varname> mem[] </varname> array after the platform device
-	resources, which implies that the total number of static and dynamic
-	memory regions cannot exceed <varname>MAX_UIO_MAPS</varname>.
-	</para>
-	<para>
-	The dynamic memory regions will be allocated when the UIO device file,
-	<varname>/dev/uioX</varname> is opened.
-	Similar to static memory resources, the memory region information for
-	dynamic regions is then visible via sysfs at
-	<varname>/sys/class/uio/uioX/maps/mapY/*</varname>.
-	The dynamic memory regions will be freed when the UIO device file is
-	closed. When no processes are holding the device file open, the address
-	returned to userspace is ~0.
-	</para>
-</sect1>
-
-</chapter>
-
-<chapter id="userspace_driver" xreflabel="Writing a driver in user space">
-<?dbhtml filename="userspace_driver.html"?>
-<title>Writing a driver in userspace</title>
-	<para>
-	Once you have a working kernel module for your hardware, you can
-	write the userspace part of your driver. You don't need any special
-	libraries, your driver can be written in any reasonable language,
-	you can use floating point numbers and so on. In short, you can
-	use all the tools and libraries you'd normally use for writing a
-	userspace application.
-	</para>
-
-<sect1 id="getting_uio_information">
-<title>Getting information about your UIO device</title>
-	<para>
-	Information about all UIO devices is available in sysfs. The
-	first thing you should do in your driver is check
-	<varname>name</varname> and <varname>version</varname> to
-	make sure your talking to the right device and that its kernel
-	driver has the version you expect.
-	</para>
-	<para>
-	You should also make sure that the memory mapping you need
-	exists and has the size you expect.
-	</para>
-	<para>
-	There is a tool called <varname>lsuio</varname> that lists
-	UIO devices and their attributes. It is available here:
-	</para>
-	<para>
-	<ulink url="http://www.osadl.org/projects/downloads/UIO/user/">
-		http://www.osadl.org/projects/downloads/UIO/user/</ulink>
-	</para>
-	<para>
-	With <varname>lsuio</varname> you can quickly check if your
-	kernel module is loaded and which attributes it exports.
-	Have a look at the manpage for details.
-	</para>
-	<para>
-	The source code of <varname>lsuio</varname> can serve as an
-	example for getting information about an UIO device.
-	The file <filename>uio_helper.c</filename> contains a lot of
-	functions you could use in your userspace driver code.
-	</para>
-</sect1>
-
-<sect1 id="mmap_device_memory">
-<title>mmap() device memory</title>
-	<para>
-	After you made sure you've got the right device with the
-	memory mappings you need, all you have to do is to call
-	<function>mmap()</function> to map the device's memory
-	to userspace.
-	</para>
-	<para>
-	The parameter <varname>offset</varname> of the
-	<function>mmap()</function> call has a special meaning
-	for UIO devices: It is used to select which mapping of
-	your device you want to map. To map the memory of
-	mapping N, you have to use N times the page size as
-	your offset:
-	</para>
-<programlisting format="linespecific">
-	offset = N * getpagesize();
-</programlisting>
-	<para>
-	N starts from zero, so if you've got only one memory
-	range to map, set <varname>offset = 0</varname>.
-	A drawback of this technique is that memory is always
-	mapped beginning with its start address.
-	</para>
-</sect1>
-
-<sect1 id="wait_for_interrupts">
-<title>Waiting for interrupts</title>
-	<para>
-	After you successfully mapped your devices memory, you
-	can access it like an ordinary array. Usually, you will
-	perform some initialization. After that, your hardware
-	starts working and will generate an interrupt as soon
-	as it's finished, has some data available, or needs your
-	attention because an error occurred.
-	</para>
-	<para>
-	<filename>/dev/uioX</filename> is a read-only file. A
-	<function>read()</function> will always block until an
-	interrupt occurs. There is only one legal value for the
-	<varname>count</varname> parameter of
-	<function>read()</function>, and that is the size of a
-	signed 32 bit integer (4). Any other value for
-	<varname>count</varname> causes <function>read()</function>
-	to fail. The signed 32 bit integer read is the interrupt
-	count of your device. If the value is one more than the value
-	you read the last time, everything is OK. If the difference
-	is greater than one, you missed interrupts.
-	</para>
-	<para>
-	You can also use <function>select()</function> on
-	<filename>/dev/uioX</filename>.
-	</para>
-</sect1>
-
-</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 (configfd &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>
-
-<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>
-	<listitem><para>
-			<ulink url="http://www.osadl.org">
-				OSADL homepage.</ulink>
-		</para></listitem>
-	<listitem><para>
-		<ulink url="http://www.linutronix.de">
-		 Linutronix homepage.</ulink>
-		</para></listitem>
-</itemizedlist>
-</appendix>
-
-</book>