[PATCH] mem.4, ioports.4: Document /dev/ioports

Josh Triplett
2014-05-09T19:21:27Z

/dev/ioports works like /dev/port, but supports 16-bit and 32-bit ports.

Signed-off-by: Josh Triplett <josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org>
---

Wasn't sure whether I should update the "Modified" notice at the top;
ideally such things should go away in favor of git.

man4/ioports.4 | 1 +
man4/mem.4 | 21 +++++++++++++++++++--
2 files changed, 20 insertions(+), 2 deletions(-)
create mode 100644 man4/ioports.4

diff --git a/man4/ioports.4 b/man4/ioports.4
new file mode 100644
index 0000000..d4c1762
--- /dev/null
+++ b/man4/ioports.4
@@ -0,0 +1 @@
+.so man4/mem.4
diff --git a/man4/mem.4 b/man4/mem.4
index 74b7b89..adfd810 100644
--- a/man4/mem.4
+++ b/man4/mem.4
@@ -25,7 +25,7 @@
.\" Modified Sat Jul 24 16:59:10 1993 by Rik Faith (faith-+5Oa3zvhR2o3uPMLIKxrzw@public.gmane.org)
.TH MEM 4 1992-11-21 "Linux" "Linux Programmer's Manual"
.SH NAME
-mem, kmem, port \- system memory, kernel memory and system ports
+mem, kmem, port, ioports \- system memory, kernel memory and system ports
.SH DESCRIPTION
.B mem
is a character device file
@@ -66,7 +66,8 @@ chown root:kmem /dev/kmem
.B port
is similar to
.BR mem ,
-but the I/O ports are accessed.
+but the I/O ports are accessed. Multi-byte reads or writes to port will
+operate on successive byte-sized ports.
.LP
It is typically created by:
.RS
@@ -75,12 +76,28 @@ mknod \-m 660 /dev/port c 1 4
.br
chown root:mem /dev/port
.RE
+.LP
+.B ioports
+is similar to
+.BR port ,
+but supports reads and writes of 16-bit or 32-bit ports. Reads or writes to
+ioport with sizes other than 1, 2, or 4 will return EINVAL.
+.LP
+It is typically created by:
+.RS
+.sp
+mknod \-m 660 /dev/ioports c 1 12
+.br
+chown root:mem /dev/ioports
+.RE
.SH FILES
.I /dev/mem
.br
.I /dev/kmem
.br
.I /dev/port
+.br
+.I /dev/ioports
.SH SEE ALSO
.BR chown (1),
.BR mknod (1),
--
2.0.0.rc2