n3xx: Change init() procedure to reduce configuration time

Previously, the init() procedure of the n3xx class passed either
the user-provided or the default clock_source and time_source values
to initialize the clocking configuration.
When the user did not provide these parameters, the default values
were assigned, overriding whatever configuration the device was
previously initialized with. Therefore, a dboard reinit was forced
when the currently configured state of the N3xx device did not match
the default configuration (i.e. internal sources).

Now, the init() procedure still provides the clock_source and
time_source values; but, if the user does not provide the
parameters, the previously used values are assigned (i.e.
self._clock_source and/or self._time_source).
By the time MPM runs this n3xx init() procedure for the first time,
both self._clock_source and self._time_source have been initialized
with the default internal values anyways in the
_init_ref_clock_and_time() procedure.

This change prevents additional, unnecessary calls to the
set_sync_source() procedure, which ultimately causes a daughterboard
reinitialization when either a new clock or time source is requested.

1 files changed, 6 insertions, 2 deletions

diff --git a/mpm/python/usrp_mpm/periph_manager/n3xx.py b/mpm/python/usrp_mpm/periph_manager/n3xx.py
index 8e0ce4463..34b07f0c4 100644
--- a/mpm/python/usrp_mpm/periph_manager/n3xx.py
+++ b/mpm/python/usrp_mpm/periph_manager/n3xx.py
@@ -387,8 +387,12 @@ class n3xx(ZynqComponents, PeriphManagerBase):
         self.enable_pps_out(False)
         # if there's no clock_source or time_source params, we added here since
         # dboards init procedures need them.
-        args['clock_source'] = args.get('clock_source', N3XX_DEFAULT_CLOCK_SOURCE)
-        args['time_source'] = args.get('time_source', N3XX_DEFAULT_TIME_SOURCE)
+        # At this point, both the self._clock_source and self._time_source global
+        # properties should have been set to either the default values (first time
+        # init() is run); or to the previous configured values (updated after a
+        # successful clocking configuration).
+        args['clock_source'] = args.get('clock_source', self._clock_source)
+        args['time_source'] = args.get('time_source', self._time_source)
         self.set_sync_source(args)
         # Uh oh, some hard coded product-related info: The N300 has no LO
         # source connectors on the front panel, so we assume that if this was