ec_openocd: fix a bunch of presubmit errors

Fix a bunch of existing presubmit detected cosmetic issues. No presubmit
warning after this patch.

BRANCH=none
BUG=b:276311425
TEST=repo upload --cbr .

Change-Id: Iccd2f39ded16fb9e36283cb80652aa56c27df460
Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4386299
Reviewed-by: Robert Zieba <robertzieba@google.com>

1 files changed, 70 insertions, 58 deletions

diff --git a/util/ec_openocd.py b/util/ec_openocd.py
index 325e1ab7c8..5da0479ed9 100755
--- a/util/ec_openocd.py
+++ b/util/ec_openocd.py
@@ -3,6 +3,9 @@
 # Copyright 2022 The ChromiumOS Authors
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
+"""
+Flashes and debugs the EC through openocd
+"""
 
 import argparse
 import dataclasses
@@ -16,10 +19,6 @@ import sys
 import time
 
 
-"""
-Flashes and debugs the EC through openocd
-"""
-
 EC_BASE = pathlib.Path(__file__).parent.parent
 
 # GDB variant to use if the board specific one is not found
@@ -28,6 +27,8 @@ FALLBACK_GDB_VARIANT = "gdb-multiarch"
 
 @dataclasses.dataclass
 class BoardInfo:
+    """Holds the board specific parameters."""
+
     gdb_variant: str
     num_breakpoints: int
     num_watchpoints: int
@@ -41,6 +42,7 @@ boards = {
 
 
 def create_openocd_args(interface, board):
+    """Return a list of arguments for initializing OpenOCD."""
     if not board in boards:
         raise RuntimeError(f"Unsupported board {board}")
 
@@ -58,6 +60,7 @@ def create_openocd_args(interface, board):
 
 
 def create_gdb_args(board, port, executable, attach):
+    """Return a list of arguments for initializing GDB."""
     if not board in boards:
         raise RuntimeError(f"Unsupported board {board}")
 
@@ -94,73 +97,79 @@ def create_gdb_args(board, port, executable, attach):
 
 
 def flash(interface, board, image, verify):
+    """Run openocd to flash the specified image file."""
     print(f"Flashing image {image}")
     # Run OpenOCD and pipe its output to stdout
     # OpenOCD will shutdown after the flashing is completed
     args = create_openocd_args(interface, board)
     args += ["-c", f'init; flash_target "{image}" {int(verify)}; shutdown']
 
-    subprocess.run(args, stdout=sys.stdout, stderr=subprocess.STDOUT)
+    subprocess.run(
+        args, stdout=sys.stdout, stderr=subprocess.STDOUT, check=True
+    )
 
 
 def debug(interface, board, port, executable, attach):
+    """Start OpenOCD and connect GDB to it."""
     # Start OpenOCD in the background
     openocd_args = create_openocd_args(interface, board)
     openocd_args += ["-c", f"gdb_port {port}"]
+    openocd_out = ""
 
-    openocd = subprocess.Popen(
+    with subprocess.Popen(  # pylint: disable=subprocess-popen-preexec-fn
         openocd_args,
         encoding="utf-8",
         stdout=subprocess.PIPE,
         stderr=subprocess.STDOUT,
         preexec_fn=os.setsid,
-    )
-
-    # Wait for OpenOCD to start, it'll open a port for GDB connections
-    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    connected = False
-    for i in range(0, 10):
-        print("Waiting for OpenOCD to start...")
-        connected = sock.connect_ex(("localhost", port))
-        if connected:
-            break
-
-        time.sleep(1000)
-
-    if not connected:
-        print(f"Failed to connect to OpenOCD on port {port}")
-        return
-
-    sock.close()
-
-    old_sigint = signal.signal(signal.SIGINT, signal.SIG_IGN)
-
-    # Start GDB
-    gdb_args = create_gdb_args(board, port, executable, attach)
-    gdb = subprocess.Popen(
-        gdb_args, stdout=sys.stdout, stderr=subprocess.STDOUT, stdin=sys.stdin
-    )
-
-    openocd_out = ""
-    while gdb.poll() == None and openocd.poll() == None:
-        (output, _) = openocd.communicate()
-        openocd_out += output
-
-    signal.signal(signal.SIGINT, old_sigint)
-
-    # Wait for OpenOCD to shutdown
-    print("Waiting for OpenOCD to finish...")
-    if openocd.poll() == None:
-        try:
-            # Read the last bit of stdout
-            (output, _) = openocd.communicate(timeout=3)
-            openocd_out += output
-        except subprocess.TimeoutExpired:
-            # OpenOCD didn't shutdown, kill it
-            openocd.kill()
-
-    if openocd.returncode != 0:
-        print("OpenOCD failed to shutdown cleanly: ")
+    ) as openocd:
+
+        # Wait for OpenOCD to start, it'll open a port for GDB connections
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        connected = False
+        for _ in range(0, 10):
+            print("Waiting for OpenOCD to start...")
+            connected = sock.connect_ex(("localhost", port))
+            if connected:
+                break
+
+            time.sleep(1000)
+
+        if not connected:
+            print(f"Failed to connect to OpenOCD on port {port}")
+            return
+
+        sock.close()
+
+        old_sigint = signal.signal(signal.SIGINT, signal.SIG_IGN)
+
+        # Start GDB
+        gdb_args = create_gdb_args(board, port, executable, attach)
+        with subprocess.Popen(
+            gdb_args,
+            stdout=sys.stdout,
+            stderr=subprocess.STDOUT,
+            stdin=sys.stdin,
+        ) as gdb:
+            while gdb.poll() is None and openocd.poll() is None:
+                (output, _) = openocd.communicate()
+                openocd_out += output
+
+        signal.signal(signal.SIGINT, old_sigint)
+
+        # Wait for OpenOCD to shutdown
+        print("Waiting for OpenOCD to finish...")
+        if openocd.poll() is None:
+            try:
+                # Read the last bit of stdout
+                (output, _) = openocd.communicate(timeout=3)
+                openocd_out += output
+            except subprocess.TimeoutExpired:
+                # OpenOCD didn't shutdown, kill it
+                openocd.kill()
+
+        if openocd.returncode != 0:
+            print("OpenOCD failed to shutdown cleanly: ")
     print(openocd_out)
 
 
@@ -182,18 +191,21 @@ def debug_external(board, port, executable, attach):
 
 
 def get_flash_file(board):
+    """Returns the path of the main output file for the board."""
     return (
         EC_BASE / "build" / "zephyr" / board / "output" / "ec.bin"
     ).resolve()
 
 
 def get_executable_file(board):
+    """Returns the path of the main RO executable file for the board."""
     return (
         EC_BASE / "build" / "zephyr" / board / "output" / "zephyr.ro.elf"
     ).resolve()
 
 
 def main():
+    """Main function."""
     parser = argparse.ArgumentParser()
     parser.add_argument(
         "--board",
@@ -233,8 +245,8 @@ def main():
 
     debug_parser = sub_parsers.add_parser(
         "debug",
-        help="Debugs the target EC through GDB, \
-        FILE selects the executable to load debug info from, defaults to using the zephyr RO executable",
+        help="Debugs the target EC through GDB, FILE selects the executable to \
+              load debug info from, defaults to using the zephyr RO executable",
     )
     debug_parser.set_defaults(command="debug")
     debug_parser.add_argument(
@@ -260,18 +272,18 @@ def main():
     args = parser.parse_args()
     # Get the image path if we were given one
     target_file = None
-    if args.file != None:
+    if args.file is not None:
         target_file = args.file.resolve()
 
     if args.command == "flash":
         image_file = (
-            get_flash_file(args.board) if target_file == None else target_file
+            get_flash_file(args.board) if target_file is None else target_file
         )
         flash(args.interface, args.board, image_file, args.verify)
     elif args.command == "debug":
         executable_file = (
             get_executable_file(args.board)
-            if target_file == None
+            if target_file is None
             else target_file
         )
         if args.external_gdbserver: