mcu: Delay reset signaling for usb to canbus bridge nodes

An mcu device acting as an "mcu bridge" should only be reset after
other normal devices are reset - otherwise the bridge wont be able to
pass along the reset message to the downstream mcus.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/klippy.py

@@ -231,8 +231,7 @@ class Printer:
         run_result = self.run_result
         try:
             if run_result == 'firmware_restart':
-                for n, m in self.lookup_objects(module='mcu'):
+                self.send_event("klippy:firmware_restart")
-                    m.microcontroller_restart()
             self.send_event("klippy:disconnect")
         except:
             logging.exception("Unhandled exception during post run")

klippy/mcu.py

@@ -563,6 +563,7 @@ class MCU:
             self._restart_method = config.getchoice('restart_method',
                                                     rmethods, None)
         self._reset_cmd = self._config_reset_cmd = None
+        self._is_mcu_bridge = False
         self._emergency_stop_cmd = None
         self._is_shutdown = self._is_timeout = False
         self._shutdown_clock = 0
@@ -589,9 +590,11 @@ class MCU:
         self._mcu_tick_stddev = 0.
         self._mcu_tick_awake = 0.
         # Register handlers
-        printer.register_event_handler("klippy:connect", self._connect)
+        printer.register_event_handler("klippy:firmware_restart",
+                                       self._firmware_restart)
         printer.register_event_handler("klippy:mcu_identify",
                                        self._mcu_identify)
+        printer.register_event_handler("klippy:connect", self._connect)
         printer.register_event_handler("klippy:shutdown", self._shutdown)
         printer.register_event_handler("klippy:disconnect", self._disconnect)
     # Serial callbacks
@@ -794,6 +797,10 @@ class MCU:
         mbaud = msgparser.get_constant('SERIAL_BAUD', None)
         if self._restart_method is None and mbaud is None and not ext_only:
             self._restart_method = 'command'
+        if msgparser.get_constant('CANBUS_BRIDGE', 0):
+            self._is_mcu_bridge = True
+            self._printer.register_event_handler("klippy:firmware_restart",
+                                                 self._firmware_restart_bridge)
         version, build_versions = msgparser.get_version_info()
         self._get_status_info['mcu_version'] = version
         self._get_status_info['mcu_build_versions'] = build_versions
@@ -911,7 +918,9 @@ class MCU:
         chelper.run_hub_ctrl(0)
         self._reactor.pause(self._reactor.monotonic() + 2.)
         chelper.run_hub_ctrl(1)
-    def microcontroller_restart(self):
+    def _firmware_restart(self, force=False):
+        if self._is_mcu_bridge and not force:
+            return
         if self._restart_method == 'rpi_usb':
             self._restart_rpi_usb()
         elif self._restart_method == 'command':
@@ -920,6 +929,8 @@ class MCU:
             self._restart_cheetah()
         else:
             self._restart_arduino()
+    def _firmware_restart_bridge(self):
+        self._firmware_restart(True)
     # Misc external commands
     def is_fileoutput(self):
         return self._printer.get_start_args().get('debugoutput') is not None

src/generic/usb_canbus.c

@@ -13,6 +13,7 @@
 #include "board/pgm.h" // PROGMEM
 #include "board/usb_cdc_ep.h" // USB_CDC_EP_BULK_IN
 #include "byteorder.h" // cpu_to_le16
+#include "command.h" // DECL_CONSTANT
 #include "generic/usbstd.h" // struct usb_device_descriptor
 #include "sched.h" // sched_wake_task
 #include "usb_cdc.h" // usb_notify_ep0
@@ -125,6 +126,8 @@ enum {
     HS_TX_LOCAL = 4,
 };
 
+DECL_CONSTANT("CANBUS_BRIDGE", 1);
+
 void
 canbus_notify_tx(void)
 {