summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2008-07-22 13:13:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-22 13:13:47 -0700
commit53baaaa9682c230410a057263d1ce2922f43ddc4 (patch)
treef5cced5622130f780d76953b284a631c3d226488 /Documentation
parentf10140fbe5f97ecfeda986a12d0f1bad75642779 (diff)
parent3f9787046ea37a26170dc4439efa21f8d23a9978 (diff)
downloadop-kernel-dev-53baaaa9682c230410a057263d1ce2922f43ddc4.zip
op-kernel-dev-53baaaa9682c230410a057263d1ce2922f43ddc4.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (79 commits) arm: bus_id -> dev_name() and dev_set_name() conversions sparc64: fix up bus_id changes in sparc core code 3c59x: handle pci_name() being const MTD: handle pci_name() being const HP iLO driver sysdev: Convert the x86 mce tolerant sysdev attribute to generic attribute sysdev: Add utility functions for simple int/ulong variable sysdev attributes sysdev: Pass the attribute to the low level sysdev show/store function driver core: Suppress sysfs warnings for device_rename(). kobject: Transmit return value of call_usermodehelper() to caller sysfs-rules.txt: reword API stability statement debugfs: Implement debugfs_remove_recursive() HOWTO: change email addresses of James in HOWTO always enable FW_LOADER unless EMBEDDED=y uio-howto.tmpl: use unique output names uio-howto.tmpl: use standard copyright/legal markings sysfs: don't call notify_change sysdev: fix debugging statements in registration code. kobject: should use kobject_put() in kset-example kobject: reorder kobject to save space on 64 bit builds ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-dev20
-rw-r--r--Documentation/DocBook/uio-howto.tmpl63
-rw-r--r--Documentation/HOWTO2
-rw-r--r--Documentation/filesystems/sysfs.txt6
-rw-r--r--Documentation/sysfs-rules.txt5
5 files changed, 80 insertions, 16 deletions
diff --git a/Documentation/ABI/testing/sysfs-dev b/Documentation/ABI/testing/sysfs-dev
new file mode 100644
index 0000000..a9f2b8b
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-dev
@@ -0,0 +1,20 @@
+What: /sys/dev
+Date: April 2008
+KernelVersion: 2.6.26
+Contact: Dan Williams <dan.j.williams@intel.com>
+Description: The /sys/dev tree provides a method to look up the sysfs
+ path for a device using the information returned from
+ stat(2). There are two directories, 'block' and 'char',
+ beneath /sys/dev containing symbolic links with names of
+ the form "<major>:<minor>". These links point to the
+ corresponding sysfs path for the given device.
+
+ Example:
+ $ readlink /sys/dev/block/8:32
+ ../../block/sdc
+
+ Entries in /sys/dev/char and /sys/dev/block will be
+ dynamically created and destroyed as devices enter and
+ leave the system.
+
+Users: mdadm <linux-raid@vger.kernel.org>
diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl
index fdd7f4f..df87d1b 100644
--- a/Documentation/DocBook/uio-howto.tmpl
+++ b/Documentation/DocBook/uio-howto.tmpl
@@ -21,6 +21,18 @@
</affiliation>
</author>
+<copyright>
+ <year>2006-2008</year>
+ <holder>Hans-Jürgen Koch.</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>
@@ -30,6 +42,12 @@
<revhistory>
<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>
@@ -57,20 +75,9 @@
</bookinfo>
<chapter id="aboutthisdoc">
-<?dbhtml filename="about.html"?>
+<?dbhtml filename="aboutthis.html"?>
<title>About this document</title>
-<sect1 id="copyright">
-<?dbhtml filename="copyright.html"?>
-<title>Copyright and License</title>
-<para>
- Copyright (c) 2006 by Hans-Jürgen Koch.</para>
-<para>
-This documentation is Free Software licensed under the terms of the
-GPL version 2.
-</para>
-</sect1>
-
<sect1 id="translations">
<?dbhtml filename="translations.html"?>
<title>Translations</title>
@@ -189,6 +196,30 @@ interested in translating it, please email me
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
@@ -362,6 +393,14 @@ device is actually used.
<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>
diff --git a/Documentation/HOWTO b/Documentation/HOWTO
index 619e8ca..c2371c5 100644
--- a/Documentation/HOWTO
+++ b/Documentation/HOWTO
@@ -358,7 +358,7 @@ Here is a list of some of the different kernel trees available:
- pcmcia, Dominik Brodowski <linux@dominikbrodowski.net>
git.kernel.org:/pub/scm/linux/kernel/git/brodo/pcmcia-2.6.git
- - SCSI, James Bottomley <James.Bottomley@SteelEye.com>
+ - SCSI, James Bottomley <James.Bottomley@hansenpartnership.com>
git.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6.git
- x86, Ingo Molnar <mingo@elte.hu>
diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt
index 7f27b8f..9e9c348 100644
--- a/Documentation/filesystems/sysfs.txt
+++ b/Documentation/filesystems/sysfs.txt
@@ -248,6 +248,7 @@ The top level sysfs directory looks like:
block/
bus/
class/
+dev/
devices/
firmware/
net/
@@ -274,6 +275,11 @@ fs/ contains a directory for some filesystems. Currently each
filesystem wanting to export attributes must create its own hierarchy
below fs/ (see ./fuse.txt for an example).
+dev/ contains two directories char/ and block/. Inside these two
+directories there are symlinks named <major>:<minor>. These symlinks
+point to the sysfs directory for the given device. /sys/dev provides a
+quick way to lookup the sysfs interface for a device from the result of
+a stat(2) operation.
More information can driver-model specific features can be found in
Documentation/driver-model/.
diff --git a/Documentation/sysfs-rules.txt b/Documentation/sysfs-rules.txt
index 80ef562..6049a2a 100644
--- a/Documentation/sysfs-rules.txt
+++ b/Documentation/sysfs-rules.txt
@@ -3,9 +3,8 @@ Rules on how to access information in the Linux kernel sysfs
The kernel-exported sysfs exports internal kernel implementation details
and depends on internal kernel structures and layout. It is agreed upon
by the kernel developers that the Linux kernel does not provide a stable
-internal API. As sysfs is a direct export of kernel internal
-structures, the sysfs interface cannot provide a stable interface either;
-it may always change along with internal kernel changes.
+internal API. Therefore, there are aspects of the sysfs interface that
+may not be stable across kernel releases.
To minimize the risk of breaking users of sysfs, which are in most cases
low-level userspace applications, with a new kernel release, the users
OpenPOWER on IntegriCloud