mpm: Reset periph manager on update

Upon updating certain components (the FPGA, for example), the
Peripheral Manager is restarted, and the overlay is reapplied. In order
to facilitate this, the RPC server intercepts and handles the
update_component function.

Tested on the RJ45 ethernet connection. It probably won't work as well
if the SFP connection goes down when the overlay is removed.

1 files changed, 16 insertions, 0 deletions

diff --git a/mpm/python/usrp_mpm/periph_manager/n310.py b/mpm/python/usrp_mpm/periph_manager/n310.py
index 7adbc85f0..79c866aa4 100644
--- a/mpm/python/usrp_mpm/periph_manager/n310.py
+++ b/mpm/python/usrp_mpm/periph_manager/n310.py
@@ -31,6 +31,7 @@ from ..net import get_mac_addr
 from ..mpmtypes import SID
 from usrp_mpm.rpc_server import no_rpc
 from usrp_mpm import net
+from usrp_mpm import dtoverlay
 from ..sysfs_gpio import SysFSGPIO
 from ..ethtable import EthDispatcherTable
 from ..liberiotable import LiberioDispatcherTable
@@ -476,10 +477,12 @@ class n310(PeriphManagerBase):
         'fpga': {
             'callback': "update_fpga",
             'path': '/lib/firmware/n3xx.bin',
+            'reset': True,
         },
         'dts': {
             'callback': "update_dts",
             'path': '/lib/firmware/n3xx.dts',
+            'reset': False,
         },
     }
 
@@ -586,6 +589,19 @@ class n310(PeriphManagerBase):
         for xport_mgr in itervalues(self._xport_mgrs):
             xport_mgr.deinit()
 
+    def tear_down(self):
+        """
+        Tear down all members that need to be specially handled before
+        deconstruction.
+        For N310, this means the overlay.
+        """
+        active_overlays = self.list_active_overlays()
+        self.log.trace("N310 has active device tree overlays: {}".format(
+            active_overlays
+        ))
+        for overlay in active_overlays:
+            dtoverlay.rm_overlay(overlay)
+
     ###########################################################################
     # Transport API
     ###########################################################################