[ISSUE-242] Un-conditionally Halt the CPU (#244)

In some instances, `.halt()` not being called can lead to un-expected behaviour
when attempting to flash or erase a target as the CPU may still be running.
This patch addresses that by removing the `.halted()` check to ensure that
`.halt()` is called un-conditionally.

Author: hkpeprah

pylink/jlink.py

@@ -2157,8 +2157,7 @@ def erase(self):
         try:
             # This has to be in a try-catch, as the device may not be in a
             # state where it can halt, but we still want to try and erase.
-            if not self.halted():
-                self.halt()
+            self.halt()
         except errors.JLinkException:
             # Can't halt, so just continue to erasing.
             pass
@@ -2209,9 +2208,8 @@ def flash(self, data, addr, on_progress=None, power_on=False, flags=0):
 
         try:
             # Stop the target before flashing.  This is required to be in a
-            # try-catch as the 'halted()' check may fail with an exception.
-            if not self.halted():
-                self.halt()
+            # try-catch as the device may not be in a state where it can halt.
+            self.halt()
         except errors.JLinkException:
             pass
 
@@ -2264,9 +2262,8 @@ def flash_file(self, path, addr, on_progress=None, power_on=False):
 
         try:
             # Stop the target before flashing.  This is required to be in a
-            # try-catch as the 'halted()' check may fail with an exception.
-            if not self.halted():
-                self.halt()
+            # try-catch as the device may not be in a state where it can halt.
+            self.halt()
         except errors.JLinkException:
             pass
 

tests/unit/test_jlink.py

@@ -2639,16 +2639,14 @@ def test_jlink_erase_failed_to_halt(self):
         Returns:
           ``None``
         """
-        self.jlink.halted = mock.Mock()
-        self.jlink.halted.side_effect = JLinkException(-1)
-
         self.jlink.halt = mock.Mock()
+        self.jlink.halt.side_effect = JLinkException(-1)
 
         self.dll.JLINK_EraseChip.return_value = 0
         self.assertEqual(0, self.jlink.erase())
 
         self.assertEqual(1, self.dll.JLINK_EraseChip.call_count)
-        self.assertEqual(0, self.jlink.halt.call_count)
+        self.assertEqual(1, self.jlink.halt.call_count)
 
     def test_jlinK_erase_failed(self):
         """Tests the J-Link ``erase()`` method when it fails to erase.
@@ -2659,18 +2657,16 @@ def test_jlinK_erase_failed(self):
         Returns:
           ``None``
         """
-        self.jlink.halted = mock.Mock()
-        self.jlink.halted.side_effect = JLinkException(-1)
-
         self.jlink.halt = mock.Mock()
+        self.jlink.halt.side_effect = JLinkException(-1)
 
         self.dll.JLINK_EraseChip.return_value = -1
 
         with self.assertRaises(JLinkException):
             self.jlink.erase()
 
         self.assertEqual(1, self.dll.JLINK_EraseChip.call_count)
-        self.assertEqual(0, self.jlink.halt.call_count)
+        self.assertEqual(1, self.jlink.halt.call_count)
 
     def test_jlink_erase_success(self):
         """Tests a successful erase of the target.
@@ -2681,9 +2677,6 @@ def test_jlink_erase_success(self):
         Returns:
           ``None``
         """
-        self.jlink.halted = mock.Mock()
-        self.jlink.halted.return_value = False
-
         self.jlink.halt = mock.Mock()
 
         self.dll.JLINK_EraseChip.return_value = 1
@@ -2718,13 +2711,11 @@ def test_jlink_flash_fail_to_flash(self):
         """
         self.dll.JLINKARM_WriteMem.return_value = 0
 
+        self.jlink.halt = mock.Mock()
         self.jlink.power_on = mock.Mock()
         self.jlink.erase = mock.Mock()
         self.jlink.memory_write = mock.Mock()
 
-        self.jlink.halted = mock.Mock()
-        self.jlink.halted.return_value = True
-
         # EndDownload failing
         self.dll.JLINKARM_EndDownload.return_value = -1
         with self.assertRaises(JLinkException):
@@ -2747,8 +2738,6 @@ def test_jlink_flash_success(self):
         self.jlink.memory_write = mock.Mock()
 
         self.jlink.halt = mock.Mock()
-        self.jlink.halted = mock.Mock()
-        self.jlink.halted.return_value = True
 
         # With a progress callback.
         self.assertEqual(0, self.jlink.flash([0], 0, util.noop))
@@ -2761,20 +2750,10 @@ def test_jlink_flash_success(self):
         self.assertEqual(0, self.jlink.flash([0], 0))
         self.dll.JLINK_SetFlashProgProgressCallback.assert_called_with(0)
 
-        # Halted exception
-        self.jlink.halted.side_effect = JLinkException(-1)
+        # Halt exception
+        self.jlink.halt.side_effect = JLinkException(-1)
         self.assertEqual(0, self.jlink.flash([0], 0))
-        self.jlink.halted.side_effect = None
-
-        # Not halted
-        self.jlink.halted.return_value = False
-        self.assertEqual(0, self.jlink.flash([0], 0))
-        self.jlink.halt.assert_called_once()
-
-        # Halted
-        self.jlink.halted.return_value = True
-        self.assertEqual(0, self.jlink.flash([0], 0))
-        self.jlink.halt.assert_called_once()
+        self.jlink.halt.side_effect = None
 
         # Without power by default
         self.jlink.power_on = mock.Mock()
@@ -2802,8 +2781,7 @@ def test_jlink_flash_file_fail_to_flash(self):
         """
         self.dll.JLINK_DownloadFile.return_value = -1
 
-        self.jlink.halted = mock.Mock()
-        self.jlink.halted.return_value = True
+        self.jlink.halt = mock.Mock()
 
         self.jlink.power_on = mock.Mock()
         self.jlink.erase = mock.Mock()
@@ -2822,9 +2800,6 @@ def test_jlink_flash_file_success(self):
         """
         self.dll.JLINK_DownloadFile.return_value = 0
 
-        self.jlink.halted = mock.Mock()
-        self.jlink.halted.return_value = True
-
         self.jlink.halt = mock.Mock()
         self.jlink.power_on = mock.Mock()
         self.jlink.erase = mock.Mock()
@@ -2840,20 +2815,10 @@ def test_jlink_flash_file_success(self):
         self.assertEqual(0, self.jlink.flash_file('path', 0))
         self.dll.JLINK_SetFlashProgProgressCallback.assert_called_with(0)
 
-        # Halted exception
-        self.jlink.halted.side_effect = JLinkException(-1)
-        self.assertEqual(0, self.jlink.flash_file('path', 0))
-        self.jlink.halted.side_effect = None
-
-        # Not halted
-        self.jlink.halted.return_value = False
-        self.assertEqual(0, self.jlink.flash_file('path', 0))
-        self.jlink.halt.assert_called_once()
-
-        # Halted
-        self.jlink.halted.return_value = True
+        # Halt exception
+        self.jlink.halt.side_effect = JLinkException(-1)
         self.assertEqual(0, self.jlink.flash_file('path', 0))
-        self.jlink.halt.assert_called_once()
+        self.jlink.halt.side_effect = None
 
         # With power
         self.jlink.power_on = mock.Mock()