Bring up the USB gadget link (package 0b, Pi side and talos side)

The Pi presents NCM Ethernet and ACM serial from a configfs gadget, started by robot-usb-gadget.service before networking. usb0 gets 10.55.0.2/30 with no gateway through netplan, matched by interface name: a MAC match turns into PermanentMACAddress= in networkd, which a gadget interface does not have, so it stayed unmanaged. talos reaches the Pi at 10.55.0.2 (ping ~2.4 ms, SSH works) through a NetworkManager profile, host/omarchy/robot-usb-link.sh, matched by the gadget's fixed host MAC. Also clamp the face's tunable parameters (focus sets a blur radius, persistence divides) and fps, after a review flagged unvalidated node parameters. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01AFN8nRRCiDiMN7ChBpHJhs
2026-10-04 20:53:09 -07:00
parent 55d33ab490
commit 69a93eeb2f
9 changed files with 181 additions and 11 deletions
@@ -0,0 +1,65 @@
+#!/bin/bash
+# Composite USB gadget for the robot, via configfs: NCM Ethernet (usb0) + ACM serial (ttyGS0).
+# Installed as /usr/local/sbin/robot-usb-gadget and run by robot-usb-gadget.service.
+#   robot-usb-gadget start | stop
+set -euo pipefail
+
+G=/sys/kernel/config/usb_gadget/hermes
+HOST_MAC=02:68:65:72:6d:01   # the host's end of the link (locally administered, spells "herm")
+DEV_MAC=02:68:65:72:6d:02    # the robot's end (usb0)
+
+stop() {
+  [ -d "$G" ] || return 0
+  cd "$G"
+  echo "" > UDC 2>/dev/null || true
+  rm -f configs/c.1/ncm.usb0 configs/c.1/acm.usb0
+  rmdir configs/c.1/strings/0x409 configs/c.1 functions/ncm.usb0 functions/acm.usb0 strings/0x409 2>/dev/null || true
+  cd /
+  rmdir "$G" 2>/dev/null || true
+}
+
+start() {
+  modprobe libcomposite
+  mountpoint -q /sys/kernel/config || mount -t configfs none /sys/kernel/config
+  stop
+  udc=
+  for _ in $(seq 40); do          # dwc2 can take a moment to register after boot
+    udc=$(ls /sys/class/udc 2>/dev/null | head -n1 || true)
+    [ -n "$udc" ] && break
+    sleep 0.5
+  done
+  [ -n "$udc" ] || { echo "robot-usb-gadget: no UDC (is dtoverlay=dwc2,dr_mode=peripheral set?)" >&2; exit 1; }
+
+  mkdir -p "$G"
+  cd "$G"
+  echo 0x1d6b > idVendor        # Linux Foundation
+  echo 0x0104 > idProduct       # multifunction composite gadget
+  echo 0x0100 > bcdDevice
+  echo 0x0200 > bcdUSB
+  echo 0xEF > bDeviceClass      # composite with interface association descriptors
+  echo 0x02 > bDeviceSubClass
+  echo 0x01 > bDeviceProtocol
+  mkdir -p strings/0x409
+  echo "$(awk '/^Serial/ {print $3}' /proc/cpuinfo)" > strings/0x409/serialnumber
+  echo "Hermes" > strings/0x409/manufacturer
+  echo "Hermes robot" > strings/0x409/product
+
+  mkdir -p configs/c.1/strings/0x409
+  echo "NCM + ACM" > configs/c.1/strings/0x409/configuration
+  echo 250 > configs/c.1/MaxPower
+
+  mkdir -p functions/ncm.usb0
+  echo "$HOST_MAC" > functions/ncm.usb0/host_addr
+  echo "$DEV_MAC" > functions/ncm.usb0/dev_addr
+  mkdir -p functions/acm.usb0
+  ln -s functions/ncm.usb0 configs/c.1/
+  ln -s functions/acm.usb0 configs/c.1/
+
+  echo "$udc" > UDC
+}
+
+case "${1:-}" in
+  start) start ;;
+  stop) stop ;;
+  *) echo "usage: $0 start|stop" >&2; exit 2 ;;
+esac