qapi-schema: add 'device_add'

Even though device_add is not fully qapi'fied, we may add it to the json
schema with 'gen': false, so registration and documentation can be
generated.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20160912091913.15831-4-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

qapi-schema.json

@@ -2200,6 +2200,46 @@
 ##
 { 'command': 'xen-set-global-dirty-log', 'data': { 'enable': 'bool' } }
 
+##
+# @device_add:
+#
+# @driver: the name of the new device's driver
+#
+# @bus: #optional the device's parent bus (device tree path)
+#
+# @id: the device's ID, must be unique
+#
+# Additional arguments depend on the type.
+#
+# Add a device.
+#
+# Notes:
+# 1. For detailed information about this command, please refer to the
+#    'docs/qdev-device-use.txt' file.
+#
+# 2. It's possible to list device properties by running QEMU with the
+#    "-device DEVICE,help" command-line argument, where DEVICE is the
+#    device's name
+#
+# Example:
+#
+# -> { "execute": "device_add",
+#      "arguments": { "driver": "e1000", "id": "net1",
+#                     "bus": "pci.0",
+#                     "mac": "52:54:00:12:34:56" } }
+# <- { "return": {} }
+#
+# TODO This command effectively bypasses QAPI completely due to its
+# "additional arguments" business.  It shouldn't have been added to
+# the schema in this form.  It should be qapified properly, or
+# replaced by a properly qapified command.
+#
+# Since: 0.13
+##
+{ 'command': 'device_add',
+  'data': {'driver': 'str', 'id': 'str'},
+  'gen': false } # so we can get the additional arguments
+
 ##
 # @device_del:
 #