flash: Add option to prevent resetting of device after programming (#…

…1492)

This adds a --no-reset command line argument that can be used to
prevent a target being reset after a program operation has finished.
The use-case for such a scenario includes when programming multiple
images whereby one of the images enables security such as disabling
the debugger, without this patch, only the first image would be
flashed.

pyocd/flash/builder.py

@@ -394,7 +394,7 @@ def add_page_with_existing_data():
                 page = add_page_with_existing_data()
                 sector_page_addr += page.size
 
-    def program(self, chip_erase=None, progress_cb=None, smart_flash=True, fast_verify=False, keep_unwritten=True):
+    def program(self, chip_erase=None, progress_cb=None, smart_flash=True, fast_verify=False, keep_unwritten=True, no_reset=False):
         """@brief Determine fastest method of flashing and then run flash programming.
 
         Data must have already been added with add_data().
@@ -419,6 +419,8 @@ def program(self, chip_erase=None, progress_cb=None, smart_flash=True, fast_veri
             written, there may be ranges of flash that would be erased but not written with new
             data. This parameter sets whether the existing contents of those unwritten ranges will
             be read from memory and restored while programming.
+        @param no_reset Boolean indicating whether if the device should not be reset after the
+            programming process has finished.
         """
 
         # Send notification that we're about to program flash.
@@ -512,7 +514,9 @@ def program(self, chip_erase=None, progress_cb=None, smart_flash=True, fast_veri
 
         # Cleanup flash algo and reset target after programming.
         self.flash.cleanup()
-        self.flash.target.reset_and_halt()
+
+        if no_reset is not True:
+            self.flash.target.reset_and_halt()
 
         program_finish = time()
         self.perf.program_time = program_finish - program_start

pyocd/flash/file_programmer.py

@@ -64,7 +64,8 @@ def __init__(self,
             chip_erase: Optional[bool] = None,
             smart_flash: Optional[bool] = None,
             trust_crc: Optional[bool] = None,
-            keep_unwritten: Optional[bool] = None
+            keep_unwritten: Optional[bool] = None,
+            no_reset: Optional[bool] = None
         ):
         """@brief Constructor.
 
@@ -85,12 +86,15 @@ def __init__(self,
             written, there may be ranges of flash that would be erased but not written with new
             data. This parameter sets whether the existing contents of those unwritten ranges will
             be read from memory and restored while programming.
+        @param no_reset Boolean indicating whether if the device should not be reset after the
+            programming process has finished.
         """
         self._session = session
         self._chip_erase = chip_erase
         self._smart_flash = smart_flash
         self._trust_crc = trust_crc
         self._keep_unwritten = keep_unwritten
+        self._no_reset = no_reset
         self._progress = progress
         self._loader = None
 
@@ -149,7 +153,8 @@ def program(self, file_or_path: Union[str, IO[bytes]], file_format: Optional[str
                                     chip_erase=self._chip_erase,
                                     smart_flash=self._smart_flash,
                                     trust_crc=self._trust_crc,
-                                    keep_unwritten=self._keep_unwritten)
+                                    keep_unwritten=self._keep_unwritten,
+                                    no_reset=self._no_reset)
 
         # file_obj = None
         # Open the file if a path was provided.

pyocd/flash/loader.py

@@ -145,14 +145,16 @@ class MemoryLoader:
     _smart_flash: Optional[bool]
     _trust_crc: Optional[bool]
     _keep_unwritten: Optional[bool]
+    _no_reset: Optional[bool]
 
     def __init__(self,
             session: "Session",
             progress: Optional[ProgressCallback] = None,
             chip_erase: Optional[bool] = None,
             smart_flash: Optional[bool] = None,
             trust_crc: Optional[bool] = None,
-            keep_unwritten: Optional[bool] = None
+            keep_unwritten: Optional[bool] = None,
+            no_reset: Optional[bool] = None
         ):
         """@brief Constructor.
 
@@ -173,6 +175,8 @@ def __init__(self,
             written, there may be ranges of flash that would be erased but not written with new
             data. This parameter sets whether the existing contents of those unwritten ranges will
             be read from memory and restored while programming.
+        @param no_reset Boolean indicating whether if the device should not be reset after the
+            programming process has finished.
         """
         self._session = session
         assert session.board
@@ -195,6 +199,8 @@ def __init__(self,
                             else self._session.options.get('fast_program')
         self._keep_unwritten = keep_unwritten if (keep_unwritten is not None) \
                             else self._session.options.get('keep_unwritten')
+        self._no_reset = no_reset if (no_reset is not None) \
+                            else self._session.options.get('no_reset')
 
         self._reset_state()
 
@@ -290,7 +296,8 @@ def commit(self):
                                     progress_cb=self._progress_cb,
                                     smart_flash=self._smart_flash,
                                     fast_verify=self._trust_crc,
-                                    keep_unwritten=self._keep_unwritten)
+                                    keep_unwritten=self._keep_unwritten,
+                                    no_reset=self._no_reset)
             perfList.append(perf)
             didChipErase = True
 

pyocd/subcommands/load_cmd.py

@@ -62,6 +62,8 @@ def get_args(cls) -> List[argparse.ArgumentParser]:
                  "all must be of this type.")
         parser_options.add_argument("--skip", metavar="BYTES", default=0, type=int_base_0,
             help="Skip programming the first N bytes. Binary files only.")
+        parser_options.add_argument("--no-reset", action="store_true",
+            help="Specify to prevent resetting device after programming has finished.")
 
         parser.add_argument("file", metavar="<file-path>", nargs="+",
             help="File to write to memory. Binary files can have an optional base address appended to the file "
@@ -96,7 +98,8 @@ def invoke(self) -> int:
         with session:
             programmer = FileProgrammer(session,
                             chip_erase=self._args.erase,
-                            trust_crc=self._args.trust_crc)
+                            trust_crc=self._args.trust_crc,
+                            no_reset=self._args.no_reset)
             for filename in self._args.file:
                 # Get an initial path with the argument as-is.
                 file_path = Path(filename).expanduser()