Laguna: bridge and management port fixes

[troglobit]

Description

Fixes and debug aids for the Laguna (LAN969x) boards, found while bringing the Tactical 1000 into the new test system.

Kernel, synced from kkit-linux-6.18.y:

• Bridge IP address unreachable (patches 0088–0090). Every bridge test on the Tactical rig failed on this. The driver stands in hardware VLAN 1 for a VLAN-unaware bridge, and confd creates bridges with vlan_default_pvid 0, which adds VLAN 1 at creation and removes it right after. That forgot the VID 1 broadcast entry, so ARP from the ports never reached the CPU, and the bridge MAC entry, so unicast to the bridge was flooded to the ports. A third fix stops the driver from forgetting a bridged port's MAC on link down, which cut the bridge off whenever its first port, whose MAC the bridge uses, was disabled. Traced with symreg on the EV23X71A.
• Link aggregates lose their MAC entry (patch 0091). The bond gives both members the first member's address, and the driver keeps one CPU entry per address, so taking one member down, or deleting the aggregate, forgot the entry the other member still used. On the rig this failed the LAG test and then every test over those ports until reboot: tunnels, NTP, PTP, static routing, DHCP. Same fix as 0087, the port addresses now share the reference counted list. Reproduced and traced with symreg on tact1 in the rig.
• Management port "lockups" (patch 0087). All standalone ports share pvid 0, so they share the MAC table entry that delivers a multicast group to the CPU, but the driver forgot it on behalf of a single port. Taking any other standalone port down, or adding it to a bridge, removed the all-nodes and mDNS entries the management port relies on. Frames were received but never forwarded to the CPU, so the unit dropped out of ixll and the test rig until the port was cycled. Fixed by reference counting the shared entries.
• Scheduling while atomic in the same path (patch 0079): ndo_set_rx_mode runs under netif_addr_lock_bh, and the MAC table access took a mutex. Now a spinlock with an atomic poll, as lan966x does. Upstream fixed it via the new ndo_set_rx_mode_async, which 6.18 does not have.
• symreg debugfs driver from Microchip's BSP (patch 0080), for register access by name.

Infix side:

• PTP never worked on the Tactical copper ports (patch 0092). Their PHYs read SKU 0x8804, the LAN8804: a LAN8814 without the 1588 unit and with the same chip ID. 6.18 takes them for full LAN8814s, creates PHY clocks and advertises PHY timestamping that never produces a timestamp, so every PTP port faulted on the first Sync. Backport of mainline 61b7ade9ba8c, which checks the SKU register and creates no PTP device on these parts; the kernel then uses the switch core timestamper for them on its own. Boards with real LAN8814s, the EV23X71A, keep stamping at the PHY. On the EV23X71A those PHY timestamps arrive over MDIO later than the 10 ms ptp4l allows, so confd now allows 100 ms with hardware timestamps.
• 802.1AS ports never left LISTENING, every gPTP test on the rig: the measured link delay on the rig exceeded the 800 ns neighbour delay threshold confd hard-coded, so neither end became asCapable. The threshold now defaults to 10 µs with hardware timestamps and mean-link-delay-thresh from the gPTP port data set is honored per port. The default matters on the Tactical, where the switch core stamps behind the PHY and the measured link delay is 1.5 µs; on the EV23X71A the PHY stamps at the wire and the delay is a few hundred ns.
• symreg package, selected by the Laguna boards, with the device tree node in each board's Infix overlay. Usage notes, including how to chase a port fault, in board/aarch64/microchip-lan969x/README.md.
• aarch64_minimal_defconfig lacked the Tactical 1000, EV23X71A and Vero W6m board packages, so PR CI images had no DTB for them and hung after Starting kernel ....
• provision-tactical did not seed uboot.env, so RAUC could not read any boot state on provisioned units.
• kernel-refresh.sh deleted the patch directory it had just regenerated when run for the current kernel version.
• log and follow moved to /etc/profile.d/, so they work in BusyBox ash on minimal builds too.

Risk analysis

Bridge fixes (0088–0090): the VID 1 broadcast entry is now permanent, like the VID 0 one for standalone ports. Standalone ports never classify to VID 1 and PGID_BCAST holds only bridged ports, so it is inert without a bridge. The shared-entry count only covers entries the driver installed itself (locked); auto-learned entries behave as before. Skipping learn and forget on up/down for bridged ports leaves those entries to the bridge FDB notifications the driver already handles; join still forgets the standalone entry and leave still restores it. Upstream has the same three bugs, hidden by the default vlan_default_pvid 1.

Lock conversion (0079): nothing sleeps or takes another lock under sparx5->lock, it nests inside the mutexes and never the reverse, and every caller is process context; the atomic switchdev notifier defers FDB work and never touches the MAC table. A softirq caller would already have been taking a mutex from softirq, so the spinlock tolerates exactly the contexts the mutex had to. Same fix lan966x took in 77bdaf39f3c8. Only behaviour change: a wedged MAC table command busy-waits up to 100 ms instead of sleeping.

Shared CPU entries (0087, 0091): list touched only on group join and leave, port up and down, bridge join and leave, and address change, held across the hardware learn/forget so two ports cannot race on the same entry. Lock order is always mc_cpu_lock then sparx5->lock.

symreg: debugfs only, root only; the driver never probes without its device tree node, so it is inert on non-Laguna boards. The tool bypasses the driver when writing, documented in the README.

Checklist

Tick relevant boxes, this PR is-a or has-a:

• Bugfix
  • Regression tests
  • ChangeLog updates (for next release)
• Feature
  • YANG model change => revision updated?
  • Regression tests added?
  • ChangeLog updates (for next release)
  • Documentation added?
• Test changes
  • Checked in changed Readme.adoc (make test-spec)
  • Added new test to group Readme.adoc and yaml file
• Code style update (formatting, renaming)
• Refactoring (please detail in commit messages)
• Build related changes
• Documentation content changes
  • ChangeLog updated (for major changes)
• Other (please describe): debug tooling (symreg)

🤖 Generated with Claude Code