Add console document

Add a little info about host console for the new obmc-console
infrastructure

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff --git a/README.md b/README.md
index c0bae54..bc76825 100644
--- a/README.md
+++ b/README.md
@@ -17,3 +17,5 @@
 
  - [rest-api.md](rest-api.md): Introduction to using the OpenBMC REST
    API
+
+ - [console.md](console.md): Using the host console
diff --git a/console.md b/console.md
new file mode 100644
index 0000000..019dcff
--- /dev/null
+++ b/console.md
@@ -0,0 +1,43 @@
+OpenBMC host console support
+============================
+
+This document describes how to connect to the host UART console from an OpenBMC
+management system.
+
+The console infrastructure allows multiple shared connections to a single host
+UART. UART data from the host is output to all connections, and input from any
+connection is sent to the host.
+
+Remote console connections
+--------------------------
+
+To connect to an OpenBMC console session remotely, just ssh to your BMC on port
+2200. Use the same login credentials you would for a normal ssh session:
+
+  $ ssh -p 2200 [user]@[bmc-hostname]
+
+
+Local console connections
+-------------------------
+
+If you're already logged into an OpenBMC machine, you can start a console
+session directly, using:
+
+  $ obmc-console-client
+
+To exit from a console, type:
+
+  return ~ .
+
+Note that if you're on an ssh connection, you'll need to 'escape' the ~
+character, by entering it twice.
+
+Logging
+-------
+
+Console logs are kept in:
+
+  /var/log/obmc-console.log
+
+This log is limited in size, and will wrap after hitting that limit (currently
+set at 16kB).