servod: make multiservo operation easier to configure
This change adds the ability to configure servod using a text file,
and new command line options to support it.
The configuration file has the following format:
- text starting with # is ignored til the end of line
- empty lines are ignored
- one per servo configuration lines consist of up to 4 comma
separated fields (the last two fields are optional):
servo-name, serial-number, port-number, board-name
where
. servo-name - a user defined symbolic name, just a reference to
a certain servo board
. serial-number - serial number of the servo board this line
pertains to
. port-number - desired port number for servod for this board,
can be overridden by the command line switch
--port or environment variable setting
SERVOD_PORT
. board-name - board configuration file to use, can be overridden
by the command line switch --board
The new command line options are:
--rcfile (-r) the name of the rc file to use
(/home/${USER}/.servodrc by default)
--name (-n) name of the servo configuration to use.
When the servod command is run on a system with multiple servos
connected, it will try to connect to the servo as defined in the
configuration file, looking it up by the serial number.
When a single servo is connected to the host, configuration file could
still be useful, as it would allow to configure the servo to connect
to a particular board and run the daemon on a particular port passing
just one command line option to servod (--name).
This change also adds the ability to specify the configuration name
and port number through environment variables SERVOD_NAME and
SERVOD_PORT respectively. This would help to make sure that
dut-control (not yet being modified) automatically communicates with
the correct servo if used in the same terminal window, where these
environment variables are set and servod was started.
Specifying name and port in the servod command line take precedence
over specifying them in the environment, which in turn takes
precedence over specifying them in the servodrc file.
An example configuration file is being introduced as well.
BUG=none
TEST=manual
The test setup includes two servos as described in the example
configuration file
. run the following commands and verify that the expected servo is
connected on the expected port:
sudo servod -n pit-4gb -r /tmp/.servodrc
sudo servod -n pit-2gb -r /tmp/.servodrc
sudo servod -sn 868534-00014 -r /tmp/.servodrc
sudo servod -sn 780735-00047 -r /tmp/.servodrc
. leave just one of the two servos connected, try the same commands,
observe commands succeed when the command line parameters match the
connected servo
. verify that connecting without specifying a config file works as
before
Change-Id: Icfd3d02a0184618ea42290ccd5408ba58fedb16a
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/177831
diff --git a/servo/data/servodrc.example b/servo/data/servodrc.example
new file mode 100644
index 0000000..168dcd5
--- /dev/null
+++ b/servo/data/servodrc.example
@@ -0,0 +1,12 @@
+# This file describes servo boards connected to this host.
+#
+# Line text starting with # to end of line is ignored, as well as empy lines.
+#
+# Configuration lines consist of up to 4 comma separated fields, the last
+# two are optional:
+#
+# name serial-number port-number board
+#
+
+pit-2gb, 868534-00014, 9900, peach_pit
+pit-4gb, 780735-00047, 9901, peach_pit
diff --git a/servo/servod.py b/servo/servod.py
index 3be288a..1343233 100755
--- a/servo/servod.py
+++ b/servo/servod.py
@@ -30,6 +30,31 @@
# port numbers are 4 digits).
DEFAULT_PORT_RANGE = (9990, 9999)
+# This text file holds servod configuration parameters. This is especially
+# handy for multi servo operation.
+#
+# The file format is pretty loose:
+# - text starting with # is ignored til the end of the line
+# - empty lines are ignored
+# - configuration lines consist of up to 4 comma separated fields (all
+# but the first field optional):
+# servo-name, serial-number, port-number, board-name
+#
+# where
+# . servo-name - a user defined symbolic name, just a reference
+# to a certain servo board
+# . serial-number - serial number of the servo board this line pertains to
+# . port-number - desired port number for servod for this board, can be
+# overridden by the command line switch --port or
+# environment variable setting SERVOD_PORT
+# . board-name - board configuration file to use, can be
+# overridden by the command line switch --board
+#
+# Since the same parameters could be defined using different means, there is a
+# hierarchy of definitions:
+# command line <- environment definition <- rc config file
+DEFAULT_RC_FILE = '/home/%s/.servodrc' % os.getenv('SUDO_USER', '')
+
class ServodError(Exception):
"""Exception class for servod server."""
@@ -67,8 +92,10 @@
parser.add_option("", "--host", default="localhost", type=str,
help="hostname to start server on")
parser.add_option("", "--port", default=None, type=int,
- help="port for server to listen on, by default " +
- "will try ports in %d..%d range" % (DEFAULT_PORT_RANGE))
+ help="port for server to listen on, by default "
+ "will try ports in %d..%d range, could also be "
+ "supplied through environment variable SERVOD_PORT" %
+ DEFAULT_PORT_RANGE)
parser.add_option("-v", "--vendor", default=None, type=int,
help="vendor id of ftdi device to interface to")
parser.add_option("-p", "--product", default=None, type=int,
@@ -84,6 +111,14 @@
parser.add_option("-i", "--interfaces", type=str, default='',
help="ordered space-delimited list of interfaces. " +
"Valid choices are gpio|i2c|uart|gpiouart|dummy")
+ parser.add_option("-r", "--rcfile", type=str,
+ default=DEFAULT_RC_FILE,
+ help="servo description file for multi-servo operation,"
+ " %s is used by default." % DEFAULT_RC_FILE)
+ parser.add_option("-n", "--name", type=str,
+ help="symbolic name of the servo board, "
+ "used as a config shortcut, could also be supplied "
+ "through environment variable SERVOD_NAME")
parser.set_usage(parser.get_usage() + examples)
return parser.parse_args()
@@ -133,25 +168,174 @@
matched_devices.append(device)
return matched_devices
-def discover_servo(logger, vendor, product, serialname):
- """Find unique servo USB device.
+def parse_rc(logger, rc_file):
+ """Parse servodrc configuration file
+
+ The format of the configuration file is described above in comments to
+ DEFAULT_RC_FILE. I the file is not found or is mis-formatted, a warning is
+ printed but the program tries to continue.
Args:
- vendor: USB vendor id (integer)
- product: USB product id (integer)
- serial: USB serial id (string)
+ logger: a logging instance used by this servod driver
+ rc_file: a string, name of the file storing the configuration
Returns:
- devices: list of usb.Device objects that are servo board(s) or
- empty list if none
+ a dictionary, where keys are symbolic servo names, and values are
+ dictionaries representing servo parameters read from the config file,
+ keyed by strings 'sn' (for serial number), 'port', and 'board'.
"""
+
+ rc = {}
+ if os.path.isfile(rc_file):
+ for rc_line in open(rc_file, 'r').readlines():
+ line = rc_line.split('#')[0].strip()
+ if not line:
+ continue
+ elts = [x.strip() for x in line.split(',')]
+ name = elts[0]
+ if not name or len(elts) < 2 or [x for x in elts if ' ' in x]:
+ logger.info('ignoring rc line "%s"', rc_line.rstrip())
+ continue
+ rc[name] = {
+ 'sn': elts[1],
+ 'port': None,
+ 'board': None
+ }
+ if (len(elts) > 2):
+ rc[name]['port'] = int(elts[2])
+ if len(elts) > 3:
+ rc[name]['board'] = elts[3]
+ if len(elts) > 4:
+ logger.info("discarding %s for for %s", ' '.join(elts[4:]), name)
+ return rc
+
+def find_servod_match(logger, options, all_servos, servodrc):
+ """Find a servo matching one of servodrc lines
+
+ Given a list of servod objects matching discovered servos, display the list
+ to the user and check if there is a configuration file line corresponding to
+ one of the servos.
+
+ If a line like that exists, and it includes options which are not yet
+ defined in the options object - set these options' values. If the option is
+ already defined - report that this config line setting is ignored.
+
+ Args:
+ logger: a logging instance used by this servod driver
+ options: an options object as returned by parse_options
+ all_servos: a list of servod objects corresponding to discovered servo
+ devices
+ servodrc: a dictionary representing the contents of the servodrc file, as
+ returned by parse_rc() above (if any)
+
+ Returns:
+ a matching servod object, if found, None otherwise
+
+ Raises:
+ ServodEror in case required name is not found in the config file
+ """
+
+ for servo in all_servos:
+ logger.info("Found servo, vid: 0x%04x pid: 0x%04x sid: %s", servo.idVendor,
+ servo.idProduct, usb_get_iserial(servo))
+
+ # If user specified servod name in the command line - match it to the serial
+ # number.
+
+ if options.name:
+ config = servodrc.get(options.name)
+ if not config:
+ raise ServodError("Name '%s' not in the config file" % options.name)
+ options.serialname = config['sn']
+ elif options.serialname:
+ # Let's try finding config for a serial name
+ for config in servodrc.itervalues():
+ if config['sn'] == options.serialname:
+ break
+ else:
+ return None
+
+ if not options.serialname:
+ # There is nothing to match
+ return None
+
+ for servo in all_servos:
+ if usb_get_iserial(servo) != options.serialname:
+ continue
+
+ # Match found, some sanity checks/updates before using it
+ matching_servo = servo
+ rc_port = config['port']
+ if rc_port:
+ if not options.port:
+ options.port = rc_port
+ else:
+ logger.warning('Ignoring rc configured port %s for servo %s',
+ rc_port, name)
+
+ rc_board = config['board']
+ if rc_board:
+ if not options.board:
+ options.board = rc_board
+ else:
+ logger.warning('Ignoring rc configured board name %s for servo %s',
+ rc_board, name)
+ return matching_servo
+
+ raise ServodError("No matching servo found")
+
+def discover_servo(logger, options, servodrc):
+ """Find a servo USB device to use
+
+ First, find all servo devices matching command line options, this may result
+ in discovering none, one or more devices.
+
+ Then try matching discovered servos and the configuration defined in
+ servodrc. A match this will result in reading missing options from servodrc
+ file.
+
+ If there is a match - return the matching device.
+
+ If no match found, but there is only one servo connected - return it. If
+ there is no match found and multiple servos are connected - report an error
+ and return None.
+
+ Args:
+ logger: a logging instance used by this servod driver
+ options: the options object returned by opt_parse
+ servodrc: a dictionary representing the contents of the servodrc file, as
+ returned by parse_rc() above (if any)
+ Returns:
+ servo object for the matching (or single) device, otherwise None
+ """
+
+ vendor, product, serialname = (options.vendor, options.product,
+ options.serialname)
all_servos = []
for (vid, pid) in servo_interfaces.SERVO_ID_DEFAULTS:
if (vendor and vendor != vid) or \
(product and product != pid):
continue
all_servos.extend(usb_find(vid, pid, serialname))
- return all_servos
+
+ if not all_servos:
+ logger.error("No servos found")
+ return None
+
+ # See if there is a matching entry in servodrc
+ matching_servo = find_servod_match(logger, options, all_servos, servodrc)
+
+ if matching_servo:
+ return matching_servo
+
+ if len(all_servos) == 1:
+ return all_servos[0]
+
+ logger.error("Use --vendor, --product or --serialname switches to "
+ "identify servo uniquely, or create a servodrc file "
+ " and use the --name switch")
+
+ return None
def get_board_version(lot_id, product_id):
"""Get board version string.
@@ -215,6 +399,27 @@
return []
return ftdi_common.SERVO_CONFIG_DEFAULTS[board_version]
+def get_env_options(logger, options):
+ """Look for non-defined options in the environment
+
+ SERVOD_PORT and SERVOD_NAME environment variables can be used if --port
+ and --name command line switches are not set. Set the options values as
+ necessary.
+
+ Args:
+ logger: a logging instance used by this servod driver
+ options: the options object returned by opt_parse
+ """
+ if not options.port:
+ env_port = os.getenv('SERVOD_PORT')
+ if env_port:
+ try:
+ options.port = int(env_port)
+ except ValueError:
+ logger.warning('Ignoring environment port definition "%s"', env_port)
+ if not options.name:
+ options.name = os.getenv('SERVOD_NAME')
+
def main_function():
(options, args) = _parse_args()
loglevel = logging.INFO
@@ -227,21 +432,16 @@
logger = logging.getLogger(os.path.basename(sys.argv[0]))
logger.info("Start")
+ get_env_options(logger, options)
- servo_like_devices = discover_servo(logger, options.vendor, options.product,
- options.serialname)
- for device in servo_like_devices:
- logger.info("Found servo, vid: 0x%04x pid: 0x%04x sid: %s", device.idVendor,
- device.idProduct, usb_get_iserial(device))
- if not servo_like_devices:
- logger.error("No servos found")
- if len(servo_like_devices) != 1:
- logger.error("Use --vendor, --product or --serialname switches to "
- "identify servo uniquely")
+ if options.name and options.serialname:
+ logger.error("Mutually exclusive '--name' or '--serialname' is allowed")
sys.exit(-1)
- servo_device = servo_like_devices[0]
-
+ servo_device = discover_servo(logger, options,
+ parse_rc(logger, options.rcfile))
+ if not servo_device:
+ sys.exit(-1)
lot_id = get_lot_id(logger, servo_device)
board_version = get_board_version(lot_id, servo_device.idProduct)
