feat(boards/helios4): enable watchdog extension by default

[iav]

The Helios4 board ships with the Marvell Armada 388 hardware watchdog (orion_wdt) but no userspace kicker is configured in the default image. After a kernel oops the machine stays hung instead of being reset.

Enable the existing 'watchdog' extension (already used by helios64, odroidm1, odroidn2): adds the 'watchdog' Debian package to the rootfs and uncomments watchdog-device in /etc/watchdog.conf, so the watchdog daemon (or wd_keepalive fallback) opens /dev/watchdog and keeps the hardware timer alive. A wedged kernel will then trigger a hardware reset within ~60s instead of requiring a manual power-cycle.

Tested on Helios4 with kernel 6.18.26-edge-mvebu: kill -9 of the watchdog daemon plus 'echo c > /proc/sysrq-trigger' produced the expected automatic reboot.

Summary by CodeRabbit

• Chores
  • Enabled watchdog functionality for the Helios4 board.

[coderabbitai]

📝 Walkthrough

Walkthrough

The Helios4 board configuration is updated to enable the watchdog extension by adding a single configuration directive. This activates watchdog functionality for the board without modifying other logic, packages, or hooks.

Changes

Watchdog Extension Enablement

Layer / File(s)	Summary
Board Configuration config/boards/helios4.conf	Added enable_extension "watchdog" directive to activate watchdog functionality on the Helios4 board.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Poem

A watchdog awakens on Helios4's gate,
One gentle line makes safety great,
The rabbit coded with careful care,
Now guardians are everywhere! 🐰⏰

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: enabling the watchdog extension for the Helios4 board by default, which directly matches the changeset modification.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

🧹 Nitpick comments (1)

config/boards/helios4.conf (1)

16-16: ⚡ Quick win

Consider adding an explanatory comment.

The uboot-btrfs extension below has a comment explaining its purpose. Adding a brief comment here would help future maintainers understand why watchdog is enabled.

📝 Suggested comment

+# Enable hardware watchdog to auto-reboot on kernel hangs
 enable_extension "watchdog"

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@config/boards/helios4.conf` at line 16, Add a short explanatory comment above
the enable_extension "watchdog" line that explains why the watchdog extension is
enabled (e.g., to ensure automatic recovery/monitoring of stalled boots or to
support board-specific hardware reset behavior). Locate the enable_extension
"watchdog" entry in the config (look for enable_extension "watchdog") and insert
a one-line comment directly above it describing its purpose and any relevant
hardware or behavior assumptions.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@config/boards/helios4.conf`:
- Line 16: Add a short explanatory comment above the enable_extension "watchdog"
line that explains why the watchdog extension is enabled (e.g., to ensure
automatic recovery/monitoring of stalled boots or to support board-specific
hardware reset behavior). Locate the enable_extension "watchdog" entry in the
config (look for enable_extension "watchdog") and insert a one-line comment
directly above it describing its purpose and any relevant hardware or behavior
assumptions.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: f7a50025-5468-49e8-af84-5e8ab2cf0fc2

📥 Commits

Reviewing files that changed from the base of the PR and between a6cb68a and c1bfe53.

📒 Files selected for processing (1)

• config/boards/helios4.conf

[github-actions]

✅ This PR has been reviewed and approved — all set for merge!