west: runners: jlink: Use registry to locate JLink executable

Instead of hardcoding a set of paths and trying to find the JLink
executable in them, use the corresponding Windows registry to locate it:

`HKEY_CURRENT_USER\\Software\\SEGGER\\J-Link`

Signed-off-by: Carles Cufi <[email protected]>
(cherry picked from commit bb1794b)

Author: carlescufi

scripts/west_commands/runners/jlink.py

@@ -5,7 +5,6 @@
 '''Runner for debugging with J-Link.'''
 
 import argparse
-import glob
 import ipaddress
 import logging
 import os
@@ -110,41 +109,34 @@ def tool_opt_help(cls) -> str:
         return "Additional options for JLink Commander, e.g. '-autoconnect 1'"
 
     @staticmethod
-    def find_jlink():
+    def default_jlink():
         global DEFAULT_JLINK_EXE
 
         if sys.platform == 'win32':
             # JLink.exe can collide with the JDK executable of the same name
-            # Look in the usual locations before falling back to $PATH
-            for root in [os.environ["ProgramFiles"], os.environ["ProgramFiles(x86)"], str(Path.home())]: # noqa SIM112
-                # SEGGER folder can contain a single "JLink" folder
-                _direct = Path(root) / "SEGGER" / "JLink" / "JLink.exe"
-                if _direct.exists():
-                    DEFAULT_JLINK_EXE = str(_direct)
-                else:
-                    # SEGGER folder can contain multiple versions such as:
-                    #   JLink_V796b
-                    #   JLink_V796t
-                    #   JLink_V798c
-                    # Find the latest version
-                    _versions = glob.glob(str(Path(root) / "SEGGER" / "JLink_V*"))
-                    if len(_versions) == 0:
-                        continue
-                    _expected_jlink = Path(_versions[-1]) / "JLink.exe"
-                    if not _expected_jlink.exists():
-                        continue
-                    DEFAULT_JLINK_EXE = str(_expected_jlink)
-                break
-            else:
-                # Not found in the normal locations, hope that $PATH is correct
+            # Locate the executable using the registry
+            try:
+                import winreg
+
+                # Note that when multiple JLink versions are installed on the
+                # machine this points to the one that was installed
+                # last, and not to the latest version.
+                key = winreg.OpenKeyEx(
+                    winreg.HKEY_CURRENT_USER, r"Software\SEGGER\J-Link")
+                DEFAULT_JLINK_EXE = (
+                    Path(winreg.QueryValueEx(key, "InstallPath")[0])
+                    / "JLink.exe")
+            except Exception:
+                # Not found via the registry, hope that $PATH is correct
                 DEFAULT_JLINK_EXE = "JLink.exe"
         else:
             DEFAULT_JLINK_EXE = "JLinkExe"
 
     @classmethod
     def do_add_parser(cls, parser):
 
-        cls.find_jlink()
+        # Find the default JLink executable
+        cls.default_jlink()
 
         # Required:
         parser.add_argument('--device', required=True, help='device name')
@@ -287,6 +279,7 @@ def do_run(self, command, **kwargs):
         # version of the tools we're using.
         self.commander = os.fspath(
             Path(self.require(self.commander)).resolve())
+        self.logger.debug(f'JLink executable: {self.commander}')
         self.logger.info(f'JLink version: {self.jlink_version_str}')
 
         rtos = self.thread_info_enabled and self.supports_thread_info