fw/target/manager: Add verify_target_responsive()

Add a method to check that the target is still responsive, and cache
the value so that the target does not need to be repeatedly probed
during various stages of wrapping up execution.

wa/framework/target/manager.py

@@ -1,6 +1,7 @@
 import logging
 
 from wa.framework import signal
+from wa.framework.exception import ExecutionError, TargetError
 from wa.framework.plugin import Parameter
 from wa.framework.target.descriptor import (get_target_description,
                                             instantiate_target,
@@ -10,7 +11,6 @@ from wa.framework.target.runtime_parameter_manager import RuntimeParameterManage
 
 from devlib import Gem5SimulationPlatform
 from devlib.utils.misc import memoized
-from devlib.exception import TargetError
 
 
 class TargetManager(object):
@@ -33,6 +33,7 @@ class TargetManager(object):
         self.target = None
         self.assistant = None
         self.platform_name = None
+        self.is_responsive = None
         self.parameters = parameters
         self.disconnect = parameters.get('disconnect')
 
@@ -82,6 +83,16 @@ class TargetManager(object):
     def commit_runtime_parameters(self, parameters):
         self.rpm.commit_runtime_parameters(parameters)
 
+    def verify_target_responsive(self):
+        if not self.target.check_responsive(explode=False):
+            self.is_responsive = False
+            if self.target.has('hard_reset'):
+                self.logger.info('Target unresponsive; performing hard reset')
+                self.target.reboot(hard=True)
+                self.is_responsive = True
+            else:
+                raise ExecutionError('Target unresponsive and hard reset not supported; bailing.')
+
     def _init_target(self):
         tdesc = get_target_description(self.target_name)
 
@@ -93,6 +104,8 @@ class TargetManager(object):
         self.target = instantiate_target(tdesc, self.parameters, connect=False,
                                          extra_platform_params=extra_plat_params)
 
+        self.is_responsive = True
+
         with signal.wrap('TARGET_CONNECT'):
             self.target.connect()
         self.logger.info('Setting up target')