doc: usage: Convert README.plan9 to reST
This converts the existing README.plan9 to reST, and puts it under
the doc/usage/os directory.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/doc/usage/os/plan9.rst b/doc/usage/os/plan9.rst
new file mode 100644
index 0000000..f91712c
--- /dev/null
+++ b/doc/usage/os/plan9.rst
@@ -0,0 +1,22 @@
+.. SPDX-License-Identifier: GPL-2.0+
+.. Steven Stallion
+.. June 2013
+
+Plan 9
+======
+
+Plan 9 from Bell Labs kernel images require additional setup to pass
+configuration information to the kernel. An environment variable named
+confaddr must be defined with the same value as CONFADDR (see mem.h).
+Use of this facility is optional, but should be preferable to manual
+configuration.
+
+When booting an image, arguments supplied to the bootm command will be
+copied to CONFADDR. If no arguments are specified, the contents of the
+bootargs environment variable will be copied.
+
+If no command line arguments or bootargs are defined, CONFADDR is left
+uninitialized to permit manual configuration. For example, PC-style
+configuration could be simulated by issuing a fatload in bootcmd::
+
+ # setenv bootcmd fatload mmc 0 $confaddr plan9.ini; ...; bootm