util/flash_jlink: Change to USB as default

This change does the following:

* allows for J-Link over USB to be the default connection
* allows for passing in hostnames as the remote target, despite
  the segger tool only accepting IP addresses
* changes the --ip arg to --remote, since this better describes
  the host + port description being provided

BRANCH=none
BUG=none
TEST=# Check over USB
     ./util/flash_jlink.py
TEST=JLinkRemoteServerCLExe
     ./util/flash_jlink.py --remote 127.0.0.1
     ./util/flash_jlink.py --remote 127.0.0.1:19020
     ./util/flash_jlink.py --remote localhost
     ./util/flash_jlink.py --remote localhost:19020
     ./util/flash_jlink.py --remote localtoast
     # Should fail
     ./util/flash_jlink.py --remote localhost:port
     # Should fail

Signed-off-by: Craig Hesling <hesling@chromium.org>
Change-Id: I63c5a250f25bcae9828dc88b6282ac301b9a519f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3054818
Reviewed-by: Josie Nordrum <josienordrum@google.com>

1 files changed, 35 insertions, 19 deletions

diff --git a/util/flash_jlink.py b/util/flash_jlink.py
index e30badd059..d2fd4dec15 100755
--- a/util/flash_jlink.py
+++ b/util/flash_jlink.py
@@ -23,6 +23,9 @@ import sys
 import tempfile
 import time
 
+
+DEFAULT_SEGGER_REMOTE_PORT = 19020
+
 # Commands are documented here: https://wiki.segger.com/J-Link_Commander
 JLINK_COMMANDS = '''
 exitonerror 1
@@ -94,29 +97,44 @@ def create_jlink_command_file(firmware_file, config):
     return tmp
 
 
-def flash(jlink_exe, ip, device, interface, cmd_file):
+def flash(jlink_exe, remote, device, interface, cmd_file):
     cmd = [
         jlink_exe,
     ]
 
-    if ip:
-        ip_components = ip.split(':')
-        if len(ip_components) != 2:
-            logging.error(f'Given ip arg "{ip}" is malformed.')
+    if remote:
+        logging.debug(f'Connecting to J-Link over TCP/IP {remote}.')
+        remote_components = remote.split(':')
+        if len(remote_components) not in [1, 2]:
+            logging.debug(f'Given remote "{remote}" is malformed.')
             return 1
-        ip_host = ip_components[0]
+
+        host = remote_components[0]
         try:
-            ip_port = int(ip_components[1])
-        except ValueError:
-            logging.error(
-                f'Given ip arg port "{ip_components[1]}" is malformed.')
+            ip = socket.gethostbyname(host)
+        except socket.gaierror as e:
+            logging.error(f'Failed to resolve host "{host}": {e}.')
             return 1
-        if not is_tcp_port_open(ip_host, ip_port):
+        logging.debug(f'Resolved {host} as {ip}.')
+        port = DEFAULT_SEGGER_REMOTE_PORT
+
+        if len(remote_components) == 2:
+            try:
+                port = int(remote_components[1])
+            except ValueError:
+                logging.error(
+                    f'Given remote port "{remote_components[1]}" is malformed.')
+                return 1
+
+        remote = f'{ip}:{port}'
+
+        logging.debug(f'Checking connection to {remote}.')
+        if not is_tcp_port_open(ip, port):
             logging.error(
-                f'JLink server doesn\'t seem to be listening on {ip}.')
+                f'JLink server doesn\'t seem to be listening on {remote}.')
             logging.error('Ensure that JLinkRemoteServerCLExe is running.')
             return 1
-        cmd.extend(['-ip', ip])
+        cmd.extend(['-ip', remote])
 
     cmd.extend([
         '-device', device,
@@ -143,12 +161,10 @@ def main(argv: list):
         help='JLinkExe path (default: ' + default_jlink + ')',
         default=default_jlink)
 
-    default_ip = '127.0.0.1:19020'
     parser.add_argument(
-        '--ip', '-n',
-        help='IP address of J-Link or machine running JLinkRemoteServerCLExe '
-             '(default: ' + default_ip + ')',
-        default=default_ip)
+        '--remote', '-n',
+        help='Use TCP/IP host[:port] to connect to a J-Link or '
+        'JLinkRemoteServerCLExe. If unspecified, connect over USB.')
 
     default_board = 'bloonchipper'
     parser.add_argument(
@@ -182,7 +198,7 @@ def main(argv: list):
     args.jlink = args.jlink
 
     cmd_file = create_jlink_command_file(args.image, config)
-    ret_code = flash(args.jlink, args.ip, config.device, config.interface,
+    ret_code = flash(args.jlink, args.remote, config.device, config.interface,
                      cmd_file.name)
     cmd_file.close()
     return ret_code