Documentation: x86: convert i386/IO-APIC.txt to reST
This converts the plain text documentation to reStructuredText format and
add it to Sphinx TOC tree. No essential content change.
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/x86/i386/IO-APIC.txt b/Documentation/x86/i386/IO-APIC.rst
similarity index 93%
rename from Documentation/x86/i386/IO-APIC.txt
rename to Documentation/x86/i386/IO-APIC.rst
index 15f5baf..ce4d8df 100644
--- a/Documentation/x86/i386/IO-APIC.txt
+++ b/Documentation/x86/i386/IO-APIC.rst
@@ -1,3 +1,11 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======
+IO-APIC
+=======
+
+:Author: Ingo Molnar <mingo@kernel.org>
+
Most (all) Intel-MP compliant SMP boards have the so-called 'IO-APIC',
which is an enhanced interrupt controller. It enables us to route
hardware interrupts to multiple CPUs, or to CPU groups. Without an
@@ -13,9 +21,8 @@
not boot Linux, then consult the linux-smp mailing list archives first.
If your box boots fine with enabled IO-APIC IRQs, then your
-/proc/interrupts will look like this one:
+/proc/interrupts will look like this one::
- ---------------------------->
hell:~> cat /proc/interrupts
CPU0
0: 1360293 IO-APIC-edge timer
@@ -28,7 +35,6 @@
NMI: 0
ERR: 0
hell:~>
- <----------------------------
Some interrupts are still listed as 'XT PIC', but this is not a problem;
none of those IRQ sources is performance-critical.
@@ -37,14 +43,14 @@
In the unlikely case that your board does not create a working mp-table,
you can use the pirq= boot parameter to 'hand-construct' IRQ entries. This
is non-trivial though and cannot be automated. One sample /etc/lilo.conf
-entry:
+entry::
append="pirq=15,11,10"
The actual numbers depend on your system, on your PCI cards and on their
PCI slot position. Usually PCI slots are 'daisy chained' before they are
connected to the PCI chipset IRQ routing facility (the incoming PIRQ1-4
-lines):
+lines)::
,-. ,-. ,-. ,-. ,-.
PIRQ4 ----| |-. ,-| |-. ,-| |-. ,-| |--------| |
@@ -56,7 +62,7 @@
PIRQ1 ----| |- `----| |- `----| |- `----| |--------| |
`-' `-' `-' `-' `-'
-Every PCI card emits a PCI IRQ, which can be INTA, INTB, INTC or INTD:
+Every PCI card emits a PCI IRQ, which can be INTA, INTB, INTC or INTD::
,-.
INTD--| |
@@ -78,19 +84,19 @@
do not use interrupts normally, thus they are not daisy chained either.
so if you have your SCSI card (IRQ11) in Slot1, Tulip card (IRQ9) in
-Slot2, then you'll have to specify this pirq= line:
+Slot2, then you'll have to specify this pirq= line::
append="pirq=11,9"
the following script tries to figure out such a default pirq= line from
-your PCI configuration:
+your PCI configuration::
echo -n pirq=; echo `scanpci | grep T_L | cut -c56-` | sed 's/ /,/g'
note that this script won't work if you have skipped a few slots or if your
board does not do default daisy-chaining. (or the IO-APIC has the PIRQ pins
connected in some strange way). E.g. if in the above case you have your SCSI
-card (IRQ11) in Slot3, and have Slot1 empty:
+card (IRQ11) in Slot3, and have Slot1 empty::
append="pirq=0,9,11"
@@ -105,7 +111,7 @@
If you have 2 PCI buses, then you can use up to 8 pirq values, although such
boards tend to have a good configuration.
-Be prepared that it might happen that you need some strange pirq line:
+Be prepared that it might happen that you need some strange pirq line::
append="pirq=0,0,0,0,0,0,9,11"
@@ -115,5 +121,3 @@
linux-kernel@vger.kernel.org if you have any problems that are not covered
by this document.
--- mingo
-
diff --git a/Documentation/x86/i386/index.rst b/Documentation/x86/i386/index.rst
new file mode 100644
index 0000000..8747cf5
--- /dev/null
+++ b/Documentation/x86/i386/index.rst
@@ -0,0 +1,10 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============
+i386 Support
+============
+
+.. toctree::
+ :maxdepth: 2
+
+ IO-APIC
diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst
index 3eb0334..4e15bcc 100644
--- a/Documentation/x86/index.rst
+++ b/Documentation/x86/index.rst
@@ -26,3 +26,4 @@
microcode
resctrl_ui
usb-legacy-support
+ i386/index
