[S390] cio: Add s390-drivers book.

s390-drivers is generated using the docbook comments. It should
eventually supersede Documentation/s390/cds.txt.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

Documentation/DocBook/Makefile

@@ -11,7 +11,7 @@ DOCBOOKS := wanbook.xml z8530book.xml mcabook.xml videobook.xml \
 	    procfs-guide.xml writing_usb_driver.xml \
 	    kernel-api.xml filesystems.xml lsm.xml usb.xml \
 	    gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \
-	    genericirq.xml
+	    genericirq.xml s390-drivers.xml
 
 ###
 # The build process is as follows (targets):

Documentation/DocBook/s390-drivers.tmpl

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
+	"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
+
+<book id="s390drivers">
+ <bookinfo>
+  <title>Writing s390 channel device drivers</title>
+
+  <authorgroup>
+   <author>
+    <firstname>Cornelia</firstname>
+    <surname>Huck</surname>
+    <affiliation>
+     <address>
+       <email>cornelia.huck@de.ibm.com</email>
+     </address>
+    </affiliation>
+   </author>
+  </authorgroup>
+
+  <copyright>
+   <year>2007</year>
+   <holder>IBM Corp.</holder>
+  </copyright>
+
+  <legalnotice>
+   <para>
+     This documentation is free software; you can redistribute
+     it and/or modify it under the terms of the GNU General Public
+     License as published by the Free Software Foundation; either
+     version 2 of the License, or (at your option) any later
+     version.
+   </para>
+
+   <para>
+     This program is distributed in the hope that it will be
+     useful, but WITHOUT ANY WARRANTY; without even the implied
+     warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+     See the GNU General Public License for more details.
+   </para>
+
+   <para>
+     You should have received a copy of the GNU General Public
+     License along with this program; if not, write to the Free
+     Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+     MA 02111-1307 USA
+   </para>
+
+   <para>
+     For more details see the file COPYING in the source
+     distribution of Linux.
+   </para>
+  </legalnotice>
+ </bookinfo>
+
+<toc></toc>
+
+  <chapter id="intro">
+   <title>Introduction</title>
+  <para>
+    This document describes the interfaces available for device drivers that
+    drive s390 based channel attached devices. This includes interfaces for
+    interaction with the hardware and interfaces for interacting with the
+    common driver core. Those interfaces are provided by the s390 common I/O
+    layer.
+  </para>
+  <para>
+    The document assumes a familarity with the technical terms associated
+    with the s390 channel I/O architecture. For a description of this
+    architecture, please refer to the "z/Architecture: Principles of
+    Operation", IBM publication no. SA22-7832.
+  </para>
+  <para>
+    While most I/O devices on a s390 system are typically driven through the
+    channel I/O mechanism described here, there are various other methods
+    (like the diag interface). These are out of the scope of this document.
+  </para>
+  <para>
+    Some additional information can also be found in the kernel source
+    under Documentation/s390/driver-model.txt.
+  </para>
+  </chapter>
+  <chapter id="ccw">
+   <title>The ccw bus</title>
+  <para>
+	The ccw bus typically contains the majority of devices available to
+	a s390 system. Named after the channel command word (ccw), the basic
+	command structure used to address its devices, the ccw bus contains
+	so-called channel attached devices. They are addressed via subchannels,
+	visible on the css bus. A device driver, however, will never interact
+	with the subchannel directly, but only via the device on the ccw bus,
+	the ccw device.
+  </para>
+    <sect1 id="channelIO">
+     <title>I/O functions for channel-attached devices</title>
+    <para>
+      Some hardware structures have been translated into C structures for use
+      by the common I/O layer and device drivers. For more information on
+      the hardware structures represented here, please consult the Principles
+      of Operation.
+    </para>
+!Iinclude/asm-s390/cio.h
+    </sect1>
+    <sect1 id="ccwdev">
+     <title>ccw devices</title>
+    <para>
+      Devices that want to initiate channel I/O need to attach to the ccw bus.
+      Interaction with the driver core is done via the common I/O layer, which
+      provides the abstractions of ccw devices and ccw device drivers.
+    </para>
+    <para>
+      The functions that initiate or terminate channel I/O all act upon a
+      ccw device structure. Device drivers must not bypass those functions
+      or strange side effects may happen.
+    </para>
+!Iinclude/asm-s390/ccwdev.h
+!Edrivers/s390/cio/device.c
+!Edrivers/s390/cio/device_ops.c
+    </sect1>
+    <sect1 id="cmf">
+     <title>The channel-measurement facility</title>
+  <para>
+	The channel-measurement facility provides a means to collect
+	measurement data which is made available by the channel subsystem
+	for each channel attached device.
+  </para>
+!Iinclude/asm-s390/cmb.h
+!Edrivers/s390/cio/cmf.c
+    </sect1>
+  </chapter>
+
+  <chapter id="ccwgroup">
+   <title>The ccwgroup bus</title>
+  <para>
+	The ccwgroup bus only contains artificial devices, created by the user.
+	Many networking devices (e.g. qeth) are in fact composed of several
+	ccw devices (like read, write and data channel for qeth). The
+	ccwgroup bus provides a mechanism to create a meta-device which
+	contains those ccw devices as slave devices and can be associated
+	with the netdevice.
+  </para>
+   <sect1 id="ccwgroupdevices">
+    <title>ccw group devices</title>
+!Iinclude/asm-s390/ccwgroup.h
+!Edrivers/s390/cio/ccwgroup.c
+   </sect1>
+  </chapter>
+
+</book>