scripts: west runners: ST-LINK GDB Server: add external-init cmd

When debugging boards with external Flash, to make it accessible for
read and write by the debugger, we need the --external-init option
together with --extload <file_path> option.
It allows the ST-LINK GDB server to make external memory accessible
after reset without any need for the app to set it up.
The external memory must be memory mapped and directly accessed because
normal memory read/write is used by gdb.

Signed-off-by: Abderrahmane JARMOUNI <[email protected]>

Author: JarmouniA

scripts/west_commands/runners/stlink_gdbserver.py

@@ -174,6 +174,7 @@ def do_attach_debug_debugserver(self, command: str):
             extldr_path = cubeprg_path / "ExternalLoader" / self._external_loader
             if not extldr_path.exists():
                 raise RuntimeError(f"External loader {self._external_loader} does not exist")
+            gdbserver_cmd += ["--external-init"]
             gdbserver_cmd += ["--extload", str(extldr_path)]
 
         self.require(gdbserver_cmd[0])