runners: opeocd: Allow loading Elf-files

In some cases especially for on-going development & debugging of real
application it might be useful to load and run not from flash but
from RAM in that case there's one catch: we cannot reset the board
after loading memory with our app.

That's because:
 a) RAM we use might be either cleared on reset or might enter
    unpredictable state with portion of previously loaded data
    being corrupted.
 b) Reset vector most probably still point to ROM/flash and so
    our current application won't be executed on reset.

So instead of "run reset" command of OpenOCD we'll use
"resume 0x12345678". Where 0x12345678 is our application's
entry-point (which BTW may very well not match beginning of
the .text section or link base).

Now to extract the entry-point we need our application's zephyr.elf
and since we already have a requirement for Elf we may use it for
loading because OpenOCD does it perfectly fine moreover automatically
detecting loaded image type (binary, hex, Elf etc).

And to use that nice feature just add "--use-elf" to west's
command-line for boards that use "openocd" runner. Like that:
----------->8--------------
west flash --use-elf
----------->8--------------

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

.github/workflows/doc-build.yml

@@ -33,6 +33,7 @@ jobs:
         pip3 install 'breathe>=4.9.1' 'docutils>=0.14' \
                      'sphinx>=1.7.5' sphinx_rtd_theme sphinx-tabs \
                      sphinxcontrib-svg2pdfconverter 'west>=0.6.2'
+        pip3 install pyelftools
 
     - name: west setup
       run: |

.github/workflows/west_cmds.yml

@@ -54,7 +54,7 @@ jobs:
           ${{ runner.os }}-pip-${{ matrix.python-version }}
     - name: install pytest
       run: |
-        pip3 install pytest west
+        pip3 install pytest west pyelftools
     - name: run pytest-win
       if: runner.os == 'Windows'
       run: |

scripts/west_commands/runners/openocd.py

@@ -5,6 +5,7 @@
 '''Runner for openocd.'''
 
 from os import path
+from elftools.elf.elffile import ELFFile
 
 from runners.core import ZephyrBinaryRunner
 
@@ -18,7 +19,7 @@ class OpenOcdBinaryRunner(ZephyrBinaryRunner):
 
     def __init__(self, cfg, pre_init=None, pre_load=None,
                  load_cmd=None, verify_cmd=None, post_verify=None,
-                 tui=None, config=None, serial=None,
+                 tui=None, config=None, serial=None, use_elf=None,
                  tcl_port=DEFAULT_OPENOCD_TCL_PORT,
                  telnet_port=DEFAULT_OPENOCD_TELNET_PORT,
                  gdb_port=DEFAULT_OPENOCD_GDB_PORT):
@@ -51,6 +52,7 @@ class OpenOcdBinaryRunner(ZephyrBinaryRunner):
         self.gdb_cmd = [cfg.gdb] if cfg.gdb else None
         self.tui_arg = ['-tui'] if tui else []
         self.serial = ['-c set _ZEPHYR_BOARD_SERIAL ' + serial] if serial else []
+        self.use_elf = use_elf
 
     @classmethod
     def name(cls):
@@ -62,6 +64,8 @@ class OpenOcdBinaryRunner(ZephyrBinaryRunner):
                             help='if given, override default config file')
         parser.add_argument('--serial', default="",
                             help='if given, selects FTDI instance by its serial number, defaults to empty')
+        parser.add_argument('--use-elf', default=False, action='store_true',
+                            help='if given, Elf file will be used for loading instead of HEX image')
         # Options for flashing:
         parser.add_argument('--cmd-pre-init', action='append',
                             help='''Command to run before calling init;
@@ -96,7 +100,7 @@ class OpenOcdBinaryRunner(ZephyrBinaryRunner):
             pre_init=args.cmd_pre_init,
             pre_load=args.cmd_pre_load, load_cmd=args.cmd_load,
             verify_cmd=args.cmd_verify, post_verify=args.cmd_post_verify,
-            tui=args.tui, config=args.config, serial=args.serial,
+            tui=args.tui, config=args.config, serial=args.serial, use_elf=args.use_elf,
             tcl_port=args.tcl_port, telnet_port=args.telnet_port,
             gdb_port=args.gdb_port)
 
@@ -107,10 +111,14 @@ class OpenOcdBinaryRunner(ZephyrBinaryRunner):
         if self.openocd_config is not None:
             self.cfg_cmd = ['-f', self.openocd_config]
 
-        if command == 'flash':
+        if command == 'flash' and self.use_elf:
+            self.do_flash_elf(**kwargs)
+        elif command == 'flash':
             self.do_flash(**kwargs)
         elif command == 'debug':
             self.do_debug(**kwargs)
+        elif command == 'load':
+            self.do_load(**kwargs)
         else:
             self.do_debugserver(**kwargs)
 
@@ -153,6 +161,29 @@ class OpenOcdBinaryRunner(ZephyrBinaryRunner):
                 '-c', 'shutdown'])
         self.check_call(cmd)
 
+    def do_flash_elf(self, **kwargs):
+        if self.elf_name is None:
+            raise ValueError('Cannot debug; no .elf specified')
+
+        # Extract entry point address from Elf to use it later with
+        # "resume" command of OpenOCD.
+        with open(self.elf_name, 'rb') as f:
+            ep_addr = f"0x{ELFFile(f).header['e_entry']:016x}"
+
+        pre_init_cmd = []
+        for i in self.pre_init:
+            pre_init_cmd.append("-c")
+            pre_init_cmd.append(i)
+
+        cmd = (self.openocd_cmd + self.serial + self.cfg_cmd +
+                      pre_init_cmd + ['-c', 'init',
+                                       '-c', 'targets',
+                                       '-c', 'halt',
+                                       '-c', 'load_image ' + self.elf_name,
+                                       '-c', 'resume ' + ep_addr,
+                                       '-c', 'shutdown'])
+        self.check_call(cmd)
+
     def do_debug(self, **kwargs):
         if self.gdb_cmd is None:
             raise ValueError('Cannot debug; no gdb specified')