dist/tools/bmp: detect unsupported targets

Instead of listing 'no targets found', detect unsupported targets as
well. Once we need to attach, assert that the target is supported.

Starting with firmware 2.0.0 of the BMP, not all targets are supported
by defaults (depends on the firmware flavor). Adding support for this
case therefore makes sense.

dist/tools/bmp/README.md

@@ -63,6 +63,10 @@ unless the probe is accessed remotely (e.g. `--port` is a network address). If
 the firmware version cannot be determined, it will assume version 1.10.2. This
 can be overridden using the `--bmp-version` flag.
 
+As of firmware version 2.0.0 of the Black Magic debugger, support for targets
+depend on the 'flavor' of firmware selected. This tool will indicate if that
+is the case.
+
 ## Examples (tested with BluePill STM32F103F8C6)
 * test connection:
 ```

dist/tools/bmp/bmp.py

@@ -105,9 +105,11 @@ def detect_targets(gdbmi, res):
     while True:
         for msg in res:
             if msg['type'] == 'target':
-                m = re.fullmatch(pattern=r"\s*(\d+)\s*(.*)\s*", string=msg['payload'])
+                m = re.fullmatch(pattern=r"([\s\*]*)(\d+)\s*(.*)\s*", string=msg['payload'])
                 if m:
-                    targets.append(m.group(2))
+                    supported = "***" not in m.group(1)
+                    description = m.group(3)
+                    targets.append((supported, description))
             elif msg['type'] == 'result':
                 assert msg['message'] == 'done', str(msg)
                 return targets
@@ -284,10 +286,13 @@ def connect_to_target(args, port):
     targets = detect_targets(gdbmi, res)
     assert len(targets) > 0, "no targets found"
     print("found following targets:")
-    for t in targets:
-        print(f"\t{t}")
+    for s, t in targets:
+        if not s:
+            print(f"\t{t} (unsupported)")
+        else:
+            print(f"\t{t}")
     print("")
-    return gdbmi
+    return (gdbmi, targets)
 
 
 def parse_args():
@@ -334,11 +339,14 @@ def main():
             debug_mode(args, port)
             sys.exit(0)
 
-        gdbmi = connect_to_target(args, port)
+        (gdbmi, targets) = connect_to_target(args, port)
 
         if args.action == 'list':
             sys.exit(0)
 
+        assert len(targets) >= args.attach, "attach greater than number of targets"
+        assert targets[args.attach - 1][0], "target unsupported by probe"
+
         assert gdb_write_and_wait_for_result(gdbmi, f'-target-attach {args.attach}', 'attaching to target')
 
         # reset mode: reset device using reset pin