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authorDavid S. Miller <davem@davemloft.net>2010-01-22 22:45:46 -0800
committerDavid S. Miller <davem@davemloft.net>2010-01-22 22:45:46 -0800
commit6be325719b3e54624397e413efd4b33a997e55a3 (patch)
tree57f321a56794cab2222e179b16731e0d76a4a68a /Documentation/DocBook
parent26d92f9276a56d55511a427fb70bd70886af647a (diff)
parent92dcffb916d309aa01778bf8963a6932e4014d07 (diff)
Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r--Documentation/DocBook/Makefile38
-rw-r--r--Documentation/DocBook/media-entities.tmpl18
-rw-r--r--Documentation/DocBook/media-indices.tmpl4
-rw-r--r--Documentation/DocBook/mtdnand.tmpl12
-rw-r--r--Documentation/DocBook/procfs-guide.tmpl626
-rw-r--r--Documentation/DocBook/procfs_example.c201
-rw-r--r--Documentation/DocBook/v4l/common.xml35
-rw-r--r--Documentation/DocBook/v4l/compat.xml16
-rw-r--r--Documentation/DocBook/v4l/v4l2.xml26
-rw-r--r--Documentation/DocBook/v4l/videodev2.h.xml116
-rw-r--r--Documentation/DocBook/v4l/vidioc-enum-dv-presets.xml238
-rw-r--r--Documentation/DocBook/v4l/vidioc-enuminput.xml36
-rw-r--r--Documentation/DocBook/v4l/vidioc-enumoutput.xml36
-rw-r--r--Documentation/DocBook/v4l/vidioc-g-dv-preset.xml111
-rw-r--r--Documentation/DocBook/v4l/vidioc-g-dv-timings.xml224
-rw-r--r--Documentation/DocBook/v4l/vidioc-g-std.xml6
-rw-r--r--Documentation/DocBook/v4l/vidioc-query-dv-preset.xml85
-rw-r--r--Documentation/DocBook/v4l/vidioc-querystd.xml6
18 files changed, 971 insertions, 863 deletions
diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile
index ab8300f67182..325cfd1d6d99 100644
--- a/Documentation/DocBook/Makefile
+++ b/Documentation/DocBook/Makefile
@@ -8,7 +8,7 @@
DOCBOOKS := z8530book.xml mcabook.xml device-drivers.xml \
kernel-hacking.xml kernel-locking.xml deviceiobook.xml \
- procfs-guide.xml writing_usb_driver.xml networking.xml \
+ writing_usb_driver.xml networking.xml \
kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \
gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \
genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \
@@ -32,10 +32,10 @@ PS_METHOD = $(prefer-db2x)
###
# The targets that may be used.
-PHONY += xmldocs sgmldocs psdocs pdfdocs htmldocs mandocs installmandocs cleandocs media
+PHONY += xmldocs sgmldocs psdocs pdfdocs htmldocs mandocs installmandocs cleandocs xmldoclinks
BOOKS := $(addprefix $(obj)/,$(DOCBOOKS))
-xmldocs: $(BOOKS)
+xmldocs: $(BOOKS) xmldoclinks
sgmldocs: xmldocs
PS := $(patsubst %.xml, %.ps, $(BOOKS))
@@ -45,15 +45,24 @@ PDF := $(patsubst %.xml, %.pdf, $(BOOKS))
pdfdocs: $(PDF)
HTML := $(sort $(patsubst %.xml, %.html, $(BOOKS)))
-htmldocs: media $(HTML)
+htmldocs: $(HTML)
$(call build_main_index)
+ $(call build_images)
MAN := $(patsubst %.xml, %.9, $(BOOKS))
mandocs: $(MAN)
-media:
- mkdir -p $(srctree)/Documentation/DocBook/media/
- cp $(srctree)/Documentation/DocBook/dvb/*.png $(srctree)/Documentation/DocBook/v4l/*.gif $(srctree)/Documentation/DocBook/media/
+build_images = mkdir -p $(objtree)/Documentation/DocBook/media/ && \
+ cp $(srctree)/Documentation/DocBook/dvb/*.png $(srctree)/Documentation/DocBook/v4l/*.gif $(objtree)/Documentation/DocBook/media/
+
+xmldoclinks:
+ifneq ($(objtree),$(srctree))
+ for dep in dvb media-entities.tmpl media-indices.tmpl v4l; do \
+ rm -f $(objtree)/Documentation/DocBook/$$dep \
+ && ln -s $(srctree)/Documentation/DocBook/$$dep $(objtree)/Documentation/DocBook/ \
+ || exit; \
+ done
+endif
installmandocs: mandocs
mkdir -p /usr/local/man/man9/
@@ -65,7 +74,7 @@ KERNELDOC = $(srctree)/scripts/kernel-doc
DOCPROC = $(objtree)/scripts/basic/docproc
XMLTOFLAGS = -m $(srctree)/Documentation/DocBook/stylesheet.xsl
-#XMLTOFLAGS += --skip-validation
+XMLTOFLAGS += --skip-validation
###
# DOCPROC is used for two purposes:
@@ -101,17 +110,6 @@ endif
# Changes in kernel-doc force a rebuild of all documentation
$(BOOKS): $(KERNELDOC)
-###
-# procfs guide uses a .c file as example code.
-# This requires an explicit dependency
-C-procfs-example = procfs_example.xml
-C-procfs-example2 = $(addprefix $(obj)/,$(C-procfs-example))
-$(obj)/procfs-guide.xml: $(C-procfs-example2)
-
-# List of programs to build
-##oops, this is a kernel module::hostprogs-y := procfs_example
-obj-m += procfs_example.o
-
# Tell kbuild to always build the programs
always := $(hostprogs-y)
@@ -238,7 +236,7 @@ clean-files := $(DOCBOOKS) \
$(patsubst %.xml, %.pdf, $(DOCBOOKS)) \
$(patsubst %.xml, %.html, $(DOCBOOKS)) \
$(patsubst %.xml, %.9, $(DOCBOOKS)) \
- $(C-procfs-example) $(index)
+ $(index)
clean-dirs := $(patsubst %.xml,%,$(DOCBOOKS)) man
diff --git a/Documentation/DocBook/media-entities.tmpl b/Documentation/DocBook/media-entities.tmpl
index bb5ab741220e..c725cb852c54 100644
--- a/Documentation/DocBook/media-entities.tmpl
+++ b/Documentation/DocBook/media-entities.tmpl
@@ -23,6 +23,7 @@
<!ENTITY VIDIOC-ENUMINPUT "<link linkend='vidioc-enuminput'><constant>VIDIOC_ENUMINPUT</constant></link>">
<!ENTITY VIDIOC-ENUMOUTPUT "<link linkend='vidioc-enumoutput'><constant>VIDIOC_ENUMOUTPUT</constant></link>">
<!ENTITY VIDIOC-ENUMSTD "<link linkend='vidioc-enumstd'><constant>VIDIOC_ENUMSTD</constant></link>">
+<!ENTITY VIDIOC-ENUM-DV-PRESETS "<link linkend='vidioc-enum-dv-presets'><constant>VIDIOC_ENUM_DV_PRESETS</constant></link>">
<!ENTITY VIDIOC-ENUM-FMT "<link linkend='vidioc-enum-fmt'><constant>VIDIOC_ENUM_FMT</constant></link>">
<!ENTITY VIDIOC-ENUM-FRAMEINTERVALS "<link linkend='vidioc-enum-frameintervals'><constant>VIDIOC_ENUM_FRAMEINTERVALS</constant></link>">
<!ENTITY VIDIOC-ENUM-FRAMESIZES "<link linkend='vidioc-enum-framesizes'><constant>VIDIOC_ENUM_FRAMESIZES</constant></link>">
@@ -30,6 +31,8 @@
<!ENTITY VIDIOC-G-AUDOUT "<link linkend='vidioc-g-audioout'><constant>VIDIOC_G_AUDOUT</constant></link>">
<!ENTITY VIDIOC-G-CROP "<link linkend='vidioc-g-crop'><constant>VIDIOC_G_CROP</constant></link>">
<!ENTITY VIDIOC-G-CTRL "<link linkend='vidioc-g-ctrl'><constant>VIDIOC_G_CTRL</constant></link>">
+<!ENTITY VIDIOC-G-DV-PRESET "<link linkend='vidioc-g-dv-preset'><constant>VIDIOC_G_DV_PRESET</constant></link>">
+<!ENTITY VIDIOC-G-DV-TIMINGS "<link linkend='vidioc-g-dv-timings'><constant>VIDIOC_G_DV_TIMINGS</constant></link>">
<!ENTITY VIDIOC-G-ENC-INDEX "<link linkend='vidioc-g-enc-index'><constant>VIDIOC_G_ENC_INDEX</constant></link>">
<!ENTITY VIDIOC-G-EXT-CTRLS "<link linkend='vidioc-g-ext-ctrls'><constant>VIDIOC_G_EXT_CTRLS</constant></link>">
<!ENTITY VIDIOC-G-FBUF "<link linkend='vidioc-g-fbuf'><constant>VIDIOC_G_FBUF</constant></link>">
@@ -53,6 +56,7 @@
<!ENTITY VIDIOC-QUERYCTRL "<link linkend='vidioc-queryctrl'><constant>VIDIOC_QUERYCTRL</constant></link>">
<!ENTITY VIDIOC-QUERYMENU "<link linkend='vidioc-queryctrl'><constant>VIDIOC_QUERYMENU</constant></link>">
<!ENTITY VIDIOC-QUERYSTD "<link linkend='vidioc-querystd'><constant>VIDIOC_QUERYSTD</constant></link>">
+<!ENTITY VIDIOC-QUERY-DV-PRESET "<link linkend='vidioc-query-dv-preset'><constant>VIDIOC_QUERY_DV_PRESET</constant></link>">
<!ENTITY VIDIOC-REQBUFS "<link linkend='vidioc-reqbufs'><constant>VIDIOC_REQBUFS</constant></link>">
<!ENTITY VIDIOC-STREAMOFF "<link linkend='vidioc-streamon'><constant>VIDIOC_STREAMOFF</constant></link>">
<!ENTITY VIDIOC-STREAMON "<link linkend='vidioc-streamon'><constant>VIDIOC_STREAMON</constant></link>">
@@ -60,6 +64,8 @@
<!ENTITY VIDIOC-S-AUDOUT "<link linkend='vidioc-g-audioout'><constant>VIDIOC_S_AUDOUT</constant></link>">
<!ENTITY VIDIOC-S-CROP "<link linkend='vidioc-g-crop'><constant>VIDIOC_S_CROP</constant></link>">
<!ENTITY VIDIOC-S-CTRL "<link linkend='vidioc-g-ctrl'><constant>VIDIOC_S_CTRL</constant></link>">
+<!ENTITY VIDIOC-S-DV-PRESET "<link linkend='vidioc-g-dv-preset'><constant>VIDIOC_S_DV_PRESET</constant></link>">
+<!ENTITY VIDIOC-S-DV-TIMINGS "<link linkend='vidioc-g-dv-timings'><constant>VIDIOC_S_DV_TIMINGS</constant></link>">
<!ENTITY VIDIOC-S-EXT-CTRLS "<link linkend='vidioc-g-ext-ctrls'><constant>VIDIOC_S_EXT_CTRLS</constant></link>">
<!ENTITY VIDIOC-S-FBUF "<link linkend='vidioc-g-fbuf'><constant>VIDIOC_S_FBUF</constant></link>">
<!ENTITY VIDIOC-S-FMT "<link linkend='vidioc-g-fmt'><constant>VIDIOC_S_FMT</constant></link>">
@@ -118,6 +124,7 @@
<!-- Structures -->
<!ENTITY v4l2-audio "struct&nbsp;<link linkend='v4l2-audio'>v4l2_audio</link>">
<!ENTITY v4l2-audioout "struct&nbsp;<link linkend='v4l2-audioout'>v4l2_audioout</link>">
+<!ENTITY v4l2-bt-timings "struct&nbsp;<link linkend='v4l2-bt-timings'>v4l2_bt_timings</link>">
<!ENTITY v4l2-buffer "struct&nbsp;<link linkend='v4l2-buffer'>v4l2_buffer</link>">
<!ENTITY v4l2-capability "struct&nbsp;<link linkend='v4l2-capability'>v4l2_capability</link>">
<!ENTITY v4l2-captureparm "struct&nbsp;<link linkend='v4l2-captureparm'>v4l2_captureparm</link>">
@@ -128,6 +135,9 @@
<!ENTITY v4l2-dbg-chip-ident "struct&nbsp;<link linkend='v4l2-dbg-chip-ident'>v4l2_dbg_chip_ident</link>">
<!ENTITY v4l2-dbg-match "struct&nbsp;<link linkend='v4l2-dbg-match'>v4l2_dbg_match</link>">
<!ENTITY v4l2-dbg-register "struct&nbsp;<link linkend='v4l2-dbg-register'>v4l2_dbg_register</link>">
+<!ENTITY v4l2-dv-enum-preset "struct&nbsp;<link linkend='v4l2-dv-enum-preset'>v4l2_dv_enum_preset</link>">
+<!ENTITY v4l2-dv-preset "struct&nbsp;<link linkend='v4l2-dv-preset'>v4l2_dv_preset</link>">
+<!ENTITY v4l2-dv-timings "struct&nbsp;<link linkend='v4l2-dv-timings'>v4l2_dv_timings</link>">
<!ENTITY v4l2-enc-idx "struct&nbsp;<link linkend='v4l2-enc-idx'>v4l2_enc_idx</link>">
<!ENTITY v4l2-enc-idx-entry "struct&nbsp;<link linkend='v4l2-enc-idx-entry'>v4l2_enc_idx_entry</link>">
<!ENTITY v4l2-encoder-cmd "struct&nbsp;<link linkend='v4l2-encoder-cmd'>v4l2_encoder_cmd</link>">
@@ -243,6 +253,10 @@
<!ENTITY sub-enumaudioout SYSTEM "v4l/vidioc-enumaudioout.xml">
<!ENTITY sub-enuminput SYSTEM "v4l/vidioc-enuminput.xml">
<!ENTITY sub-enumoutput SYSTEM "v4l/vidioc-enumoutput.xml">
+<!ENTITY sub-enum-dv-presets SYSTEM "v4l/vidioc-enum-dv-presets.xml">
+<!ENTITY sub-g-dv-preset SYSTEM "v4l/vidioc-g-dv-preset.xml">
+<!ENTITY sub-query-dv-preset SYSTEM "v4l/vidioc-query-dv-preset.xml">
+<!ENTITY sub-g-dv-timings SYSTEM "v4l/vidioc-g-dv-timings.xml">
<!ENTITY sub-enumstd SYSTEM "v4l/vidioc-enumstd.xml">
<!ENTITY sub-g-audio SYSTEM "v4l/vidioc-g-audio.xml">
<!ENTITY sub-g-audioout SYSTEM "v4l/vidioc-g-audioout.xml">
@@ -333,6 +347,10 @@
<!ENTITY enumaudioout SYSTEM "v4l/vidioc-enumaudioout.xml">
<!ENTITY enuminput SYSTEM "v4l/vidioc-enuminput.xml">
<!ENTITY enumoutput SYSTEM "v4l/vidioc-enumoutput.xml">
+<!ENTITY enum-dv-presets SYSTEM "v4l/vidioc-enum-dv-presets.xml">
+<!ENTITY g-dv-preset SYSTEM "v4l/vidioc-g-dv-preset.xml">
+<!ENTITY query-dv-preset SYSTEM "v4l/vidioc-query-dv-preset.xml">
+<!ENTITY g-dv-timings SYSTEM "v4l/vidioc-g-dv-timings.xml">
<!ENTITY enumstd SYSTEM "v4l/vidioc-enumstd.xml">
<!ENTITY g-audio SYSTEM "v4l/vidioc-g-audio.xml">
<!ENTITY g-audioout SYSTEM "v4l/vidioc-g-audioout.xml">
diff --git a/Documentation/DocBook/media-indices.tmpl b/Documentation/DocBook/media-indices.tmpl
index 9e30a236d74f..78d6031de001 100644
--- a/Documentation/DocBook/media-indices.tmpl
+++ b/Documentation/DocBook/media-indices.tmpl
@@ -36,6 +36,7 @@
<indexentry><primaryie>enum&nbsp;<link linkend='v4l2-preemphasis'>v4l2_preemphasis</link></primaryie></indexentry>
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-audio'>v4l2_audio</link></primaryie></indexentry>
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-audioout'>v4l2_audioout</link></primaryie></indexentry>
+<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-bt-timings'>v4l2_bt_timings</link></primaryie></indexentry>
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-buffer'>v4l2_buffer</link></primaryie></indexentry>
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-capability'>v4l2_capability</link></primaryie></indexentry>
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-captureparm'>v4l2_captureparm</link></primaryie></indexentry>
@@ -46,6 +47,9 @@
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-dbg-chip-ident'>v4l2_dbg_chip_ident</link></primaryie></indexentry>
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-dbg-match'>v4l2_dbg_match</link></primaryie></indexentry>
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-dbg-register'>v4l2_dbg_register</link></primaryie></indexentry>
+<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-dv-enum-preset'>v4l2_dv_enum_preset</link></primaryie></indexentry>
+<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-dv-preset'>v4l2_dv_preset</link></primaryie></indexentry>
+<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-dv-timings'>v4l2_dv_timings</link></primaryie></indexentry>
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-enc-idx'>v4l2_enc_idx</link></primaryie></indexentry>
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-enc-idx-entry'>v4l2_enc_idx_entry</link></primaryie></indexentry>
<indexentry><primaryie>struct&nbsp;<link linkend='v4l2-encoder-cmd'>v4l2_encoder_cmd</link></primaryie></indexentry>
diff --git a/Documentation/DocBook/mtdnand.tmpl b/Documentation/DocBook/mtdnand.tmpl
index f508a8a27fea..5e7d84b48505 100644
--- a/Documentation/DocBook/mtdnand.tmpl
+++ b/Documentation/DocBook/mtdnand.tmpl
@@ -174,7 +174,7 @@
</para>
<programlisting>
static struct mtd_info *board_mtd;
-static unsigned long baseaddr;
+static void __iomem *baseaddr;
</programlisting>
<para>
Static example
@@ -182,7 +182,7 @@ static unsigned long baseaddr;
<programlisting>
static struct mtd_info board_mtd;
static struct nand_chip board_chip;
-static unsigned long baseaddr;
+static void __iomem *baseaddr;
</programlisting>
</sect1>
<sect1 id="Partition_defines">
@@ -283,8 +283,8 @@ int __init board_init (void)
}
/* map physical address */
- baseaddr = (unsigned long)ioremap(CHIP_PHYSICAL_ADDRESS, 1024);
- if(!baseaddr){
+ baseaddr = ioremap(CHIP_PHYSICAL_ADDRESS, 1024);
+ if (!baseaddr) {
printk("Ioremap to access NAND chip failed\n");
err = -EIO;
goto out_mtd;
@@ -316,7 +316,7 @@ int __init board_init (void)
goto out;
out_ior:
- iounmap((void *)baseaddr);
+ iounmap(baseaddr);
out_mtd:
kfree (board_mtd);
out:
@@ -341,7 +341,7 @@ static void __exit board_cleanup (void)
nand_release (board_mtd);
/* unmap physical address */
- iounmap((void *)baseaddr);
+ iounmap(baseaddr);
/* Free the MTD device structure */
kfree (board_mtd);
diff --git a/Documentation/DocBook/procfs-guide.tmpl b/Documentation/DocBook/procfs-guide.tmpl
deleted file mode 100644
index 9eba4b7af73d..000000000000
--- a/Documentation/DocBook/procfs-guide.tmpl
+++ /dev/null
@@ -1,626 +0,0 @@
-<?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" [
-<!ENTITY procfsexample SYSTEM "procfs_example.xml">
-]>
-
-<book id="LKProcfsGuide">
- <bookinfo>
- <title>Linux Kernel Procfs Guide</title>
-
- <authorgroup>
- <author>
- <firstname>Erik</firstname>
- <othername>(J.A.K.)</othername>
- <surname>Mouw</surname>
- <affiliation>
- <address>
- <email>mouw@nl.linux.org</email>
- </address>
- </affiliation>
- </author>
- <othercredit>
- <contrib>
- This software and documentation were written while working on the
- LART computing board
- (<ulink url="http://www.lartmaker.nl/">http://www.lartmaker.nl/</ulink>),
- which was sponsored by the Delt University of Technology projects
- Mobile Multi-media Communications and Ubiquitous Communications.
- </contrib>
- </othercredit>
- </authorgroup>
-
- <revhistory>
- <revision>
- <revnumber>1.0</revnumber>
- <date>May 30, 2001</date>
- <revremark>Initial revision posted to linux-kernel</revremark>
- </revision>
- <revision>
- <revnumber>1.1</revnumber>
- <date>June 3, 2001</date>
- <revremark>Revised after comments from linux-kernel</revremark>
- </revision>
- </revhistory>
-
- <copyright>
- <year>2001</year>
- <holder>Erik Mouw</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 documentation 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>
-
-
-
-
- <preface id="Preface">
- <title>Preface</title>
-
- <para>
- This guide describes the use of the procfs file system from
- within the Linux kernel. The idea to write this guide came up on
- the #kernelnewbies IRC channel (see <ulink
- url="http://www.kernelnewbies.org/">http://www.kernelnewbies.org/</ulink>),
- when Jeff Garzik explained the use of procfs and forwarded me a
- message Alexander Viro wrote to the linux-kernel mailing list. I
- agreed to write it up nicely, so here it is.
- </para>
-
- <para>
- I'd like to thank Jeff Garzik
- <email>jgarzik@pobox.com</email> and Alexander Viro
- <email>viro@parcelfarce.linux.theplanet.co.uk</email> for their input,
- Tim Waugh <email>twaugh@redhat.com</email> for his <ulink
- url="http://people.redhat.com/twaugh/docbook/selfdocbook/">Selfdocbook</ulink>,
- and Marc Joosen <email>marcj@historia.et.tudelft.nl</email> for
- proofreading.
- </para>
-
- <para>
- Erik
- </para>
- </preface>
-
-
-
-
- <chapter id="intro">
- <title>Introduction</title>
-
- <para>
- The <filename class="directory">/proc</filename> file system
- (procfs) is a special file system in the linux kernel. It's a
- virtual file system: it is not associated with a block device
- but exists only in memory. The files in the procfs are there to
- allow userland programs access to certain information from the
- kernel (like process information in <filename
- class="directory">/proc/[0-9]+/</filename>), but also for debug
- purposes (like <filename>/proc/ksyms</filename>).
- </para>
-
- <para>
- This guide describes the use of the procfs file system from
- within the Linux kernel. It starts by introducing all relevant
- functions to manage the files within the file system. After that
- it shows how to communicate with userland, and some tips and
- tricks will be pointed out. Finally a complete example will be
- shown.
- </para>
-
- <para>
- Note that the files in <filename
- class="directory">/proc/sys</filename> are sysctl files: they
- don't belong to procfs and are governed by a completely
- different API described in the Kernel API book.
- </para>
- </chapter>
-
-
-
-
- <chapter id="managing">
- <title>Managing procfs entries</title>
-
- <para>
- This chapter describes the functions that various kernel
- components use to populate the procfs with files, symlinks,
- device nodes, and directories.
- </para>
-
- <para>
- A minor note before we start: if you want to use any of the
- procfs functions, be sure to include the correct header file!
- This should be one of the first lines in your code:
- </para>
-
- <programlisting>
-#include &lt;linux/proc_fs.h&gt;
- </programlisting>
-
-
-
-
- <sect1 id="regularfile">
- <title>Creating a regular file</title>
-
- <funcsynopsis>
- <funcprototype>
- <funcdef>struct proc_dir_entry* <function>create_proc_entry</function></funcdef>
- <paramdef>const char* <parameter>name</parameter></paramdef>
- <paramdef>mode_t <parameter>mode</parameter></paramdef>
- <paramdef>struct proc_dir_entry* <parameter>parent</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
-
- <para>
- This function creates a regular file with the name
- <parameter>name</parameter>, file mode
- <parameter>mode</parameter> in the directory
- <parameter>parent</parameter>. To create a file in the root of
- the procfs, use <constant>NULL</constant> as
- <parameter>parent</parameter> parameter. When successful, the
- function will return a pointer to the freshly created
- <structname>struct proc_dir_entry</structname>; otherwise it
- will return <constant>NULL</constant>. <xref
- linkend="userland"/> describes how to do something useful with
- regular files.
- </para>
-
- <para>
- Note that it is specifically supported that you can pass a
- path that spans multiple directories. For example
- <function>create_proc_entry</function>(<parameter>"drivers/via0/info"</parameter>)
- will create the <filename class="directory">via0</filename>
- directory if necessary, with standard
- <constant>0755</constant> permissions.
- </para>
-
- <para>
- If you only want to be able to read the file, the function
- <function>create_proc_read_entry</function> described in <xref
- linkend="convenience"/> may be used to create and initialise
- the procfs entry in one single call.
- </para>
- </sect1>
-
-
-
-
- <sect1 id="Creating_a_symlink">
- <title>Creating a symlink</title>
-
- <funcsynopsis>
- <funcprototype>
- <funcdef>struct proc_dir_entry*
- <function>proc_symlink</function></funcdef> <paramdef>const
- char* <parameter>name</parameter></paramdef>
- <paramdef>struct proc_dir_entry*
- <parameter>parent</parameter></paramdef> <paramdef>const
- char* <parameter>dest</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
-
- <para>
- This creates a symlink in the procfs directory
- <parameter>parent</parameter> that points from
- <parameter>name</parameter> to
- <parameter>dest</parameter>. This translates in userland to
- <literal>ln -s</literal> <parameter>dest</parameter>
- <parameter>name</parameter>.
- </para>
- </sect1>
-
- <sect1 id="Creating_a_directory">
- <title>Creating a directory</title>
-
- <funcsynopsis>
- <funcprototype>
- <funcdef>struct proc_dir_entry* <function>proc_mkdir</function></funcdef>
- <paramdef>const char* <parameter>name</parameter></paramdef>
- <paramdef>struct proc_dir_entry* <parameter>parent</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
-
- <para>
- Create a directory <parameter>name</parameter> in the procfs
- directory <parameter>parent</parameter>.
- </para>
- </sect1>
-
-
-
-
- <sect1 id="Removing_an_entry">
- <title>Removing an entry</title>
-
- <funcsynopsis>
- <funcprototype>
- <funcdef>void <function>remove_proc_entry</function></funcdef>
- <paramdef>const char* <parameter>name</parameter></paramdef>
- <paramdef>struct proc_dir_entry* <parameter>parent</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
-
- <para>
- Removes the entry <parameter>name</parameter> in the directory
- <parameter>parent</parameter> from the procfs. Entries are
- removed by their <emphasis>name</emphasis>, not by the
- <structname>struct proc_dir_entry</structname> returned by the
- various create functions. Note that this function doesn't
- recursively remove entries.
- </para>
-
- <para>
- Be sure to free the <structfield>data</structfield> entry from
- the <structname>struct proc_dir_entry</structname> before
- <function>remove_proc_entry</function> is called (that is: if
- there was some <structfield>data</structfield> allocated, of
- course). See <xref linkend="usingdata"/> for more information
- on using the <structfield>data</structfield> entry.
- </para>
- </sect1>
- </chapter>
-
-
-
-
- <chapter id="userland">
- <title>Communicating with userland</title>
-
- <para>
- Instead of reading (or writing) information directly from
- kernel memory, procfs works with <emphasis>call back
- functions</emphasis> for files: functions that are called when
- a specific file is being read or written. Such functions have
- to be initialised after the procfs file is created by setting
- the <structfield>read_proc</structfield> and/or
- <structfield>write_proc</structfield> fields in the
- <structname>struct proc_dir_entry*</structname> that the
- function <function>create_proc_entry</function> returned:
- </para>
-
- <programlisting>
-struct proc_dir_entry* entry;
-
-entry->read_proc = read_proc_foo;
-entry->write_proc = write_proc_foo;
- </programlisting>
-
- <para>
- If you only want to use a the
- <structfield>read_proc</structfield>, the function
- <function>create_proc_read_entry</function> described in <xref
- linkend="convenience"/> may be used to create and initialise the
- procfs entry in one single call.
- </para>
-
-
-
- <sect1 id="Reading_data">
- <title>Reading data</title>
-
- <para>
- The read function is a call back function that allows userland
- processes to read data from the kernel. The read function
- should have the following format:
- </para>
-
- <funcsynopsis>
- <funcprototype>
- <funcdef>int <function>read_func</function></funcdef>
- <paramdef>char* <parameter>buffer</parameter></paramdef>
- <paramdef>char** <parameter>start</parameter></paramdef>
- <paramdef>off_t <parameter>off</parameter></paramdef>
- <paramdef>int <parameter>count</parameter></paramdef>
- <paramdef>int* <parameter>peof</parameter></paramdef>
- <paramdef>void* <parameter>data</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
-
- <para>
- The read function should write its information into the
- <parameter>buffer</parameter>, which will be exactly
- <literal>PAGE_SIZE</literal> bytes long.
- </para>
-
- <para>
- The parameter
- <parameter>peof</parameter> should be used to signal that the
- end of the file has been reached by writing
- <literal>1</literal> to the memory location
- <parameter>peof</parameter> points to.
- </para>
-
- <para>
- The <parameter>data</parameter>
- parameter can be used to create a single call back function for
- several files, see <xref linkend="usingdata"/>.
- </para>
-
- <para>
- The rest of the parameters and the return value are described
- by a comment in <filename>fs/proc/generic.c</filename> as follows:
- </para>
-
- <blockquote>
- <para>
- You have three ways to return data:
- </para>
- <orderedlist>
- <listitem>
- <para>
- Leave <literal>*start = NULL</literal>. (This is the default.)
- Put the data of the requested offset at that
- offset within the buffer. Return the number (<literal>n</literal>)
- of bytes there are from the beginning of the
- buffer up to the last byte of data. If the
- number of supplied bytes (<literal>= n - offset</literal>) is
- greater than zero and you didn't signal eof
- and the reader is prepared to take more data
- you will be called again with the requested
- offset advanced by the number of bytes
- absorbed. This interface is useful for files
- no larger than the buffer.
- </para>
- </listitem>
- <listitem>
- <para>
- Set <literal>*start</literal> to an unsigned long value less than
- the buffer address but greater than zero.
- Put the data of the requested offset at the
- beginning of the buffer. Return the number of
- bytes of data placed there. If this number is
- greater than zero and you didn't signal eof
- and the reader is prepared to take more data
- you will be called again with the requested
- offset advanced by <literal>*start</literal>. This interface is
- useful when you have a large file consisting
- of a series of blocks which you want to count
- and return as wholes.
- (Hack by Paul.Russell@rustcorp.com.au)
- </para>
- </listitem>
- <listitem>
- <para>
- Set <literal>*start</literal> to an address within the buffer.
- Put the data of the requested offset at <literal>*start</literal>.
- Return the number of bytes of data placed there.
- If this number is greater than zero and you
- didn't signal eof and the reader is prepared to
- take more data you will be called again with the
- requested offset advanced by the number of bytes
- absorbed.
- </para>
- </listitem>
- </orderedlist>
- </blockquote>
-
- <para>
- <xref linkend="example"/> shows how to use a read call back
- function.
- </para>
- </sect1>
-
-
-
-
- <sect1 id="Writing_data">
- <title>Writing data</title>
-
- <para>
- The write call back function allows a userland process to write
- data to the kernel, so it has some kind of control over the
- kernel. The write function should have the following format:
- </para>
-
- <funcsynopsis>
- <funcprototype>
- <funcdef>int <function>write_func</function></funcdef>
- <paramdef>struct file* <parameter>file</parameter></paramdef>
- <paramdef>const char* <parameter>buffer</parameter></paramdef>
- <paramdef>unsigned long <parameter>count</parameter></paramdef>
- <paramdef>void* <parameter>data</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
-
- <para>
- The write function should read <parameter>count</parameter>
- bytes at maximum from the <parameter>buffer</parameter>. Note
- that the <parameter>buffer</parameter> doesn't live in the
- kernel's memory space, so it should first be copied to kernel
- space with <function>copy_from_user</function>. The
- <parameter>file</parameter> parameter is usually
- ignored. <xref linkend="usingdata"/> shows how to use the
- <parameter>data</parameter> parameter.
- </para>
-
- <para>
- Again, <xref linkend="example"/> shows how to use this call back
- function.
- </para>
- </sect1>
-