Initial commit: Arduino Uno Q USB Audio Synth project

- USB gadget (UAC1 + MIDI) with boot persistence
- USB host mode with auto-detection
- Pure Data synth patch with ALSA + UDP netreceive MIDI input
- MIDI rawmidi-to-UDP bridge (midi-bridge.py)
- LED matrix visualization (led-matrix-viz.py via arduino-router RPC)
- MCU sketch for LED matrix control (Arduino_RouterBridge + ArduinoGraphics)
- Conftest/OPA Rego policy validation suite for .pd files
- gen_synth_pd.py: programmatic .pd file generator
- System services: midi-bridge, led-matrix-viz, pd-synth-auto, usb-role-detect
- Justfile with deploy, enable, diagnostic recipes
- Diagnostic script (diag.sh)

scripts/diag.sh

@@ -0,0 +1,103 @@
+#!/bin/bash
+# diag.sh — run on the board for diagnostics
+set -e
+
+echo "--- System ---"
+echo "  Kernel:     $(uname -r)"
+echo "  Uptime:     $(uptime -p | sed 's/up //')"
+echo "  Load:       $(cat /proc/loadavg | cut -d' ' -f1-3)"
+echo "  Memory:     $(free -h | awk '/^Mem:/{print $3 "/" $2}')"
+echo "  Disk:       $(df -h / | awk 'NR==2{print $3 "/" $2 " (" $5 ")"}')"
+
+echo ""
+echo "--- USB Gadget (configfs) ---"
+UDC=$(cat /sys/kernel/config/usb_gadget/g1/UDC 2>/dev/null || echo '(not bound)')
+echo "  UDC bound:  $UDC"
+for f in /sys/kernel/config/usb_gadget/g1/functions/*/; do
+    echo "  Function:   $(basename "$f")"
+done
+for c in /sys/kernel/config/usb_gadget/g1/configs/*/; do
+    cfg=$(basename "$c")
+    for l in "$c"/*.*/; do
+        [ -L "$l" ] && echo "  linked:     $(basename "$l") -> config $cfg"
+    done
+done
+
+echo ""
+echo "--- UDC Hardware ---"
+for u in /sys/class/udc/*/; do
+    name=$(basename "$u")
+    echo "  Controller: $name"
+    echo "    state:      $(cat "$u/state" 2>/dev/null)"
+    echo "    speed:      $(cat "$u/current_speed" 2>/dev/null)"
+    echo "    max_speed:  $(cat "$u/maximum_speed" 2>/dev/null)"
+done
+role=$(cat /sys/class/usb_role/*/role 2>/dev/null || echo '(none)')
+echo "  USB role:   $role"
+echo "  Role sw:    $(ls /sys/class/usb_role/ 2>/dev/null | tr '\n' ' ')"
+
+echo ""
+echo "--- USB Audio Params ---"
+for p in /sys/kernel/config/usb_gadget/g1/functions/uac1.gs0/p_* /sys/kernel/config/usb_gadget/g1/functions/uac1.gs0/c_*; do
+    name=$(basename "$p")
+    echo "  $name: $(cat "$p" 2>/dev/null)"
+done
+
+echo ""
+echo "--- USB MIDI Params ---"
+for p in in_ports out_ports index; do
+    val=$(cat /sys/kernel/config/usb_gadget/g1/functions/midi.gs0/$p 2>/dev/null)
+    echo "  $p: $val"
+done
+
+echo ""
+echo "--- Modules ---"
+lsmod | awk '$1 ~ /^(usb_f_|u_audio|libcomposite|snd_usb|snd_rawmidi|snd_soc|dwc3)/ {print "  " $0}'
+for m in usb_f_uac1 usb_f_midi dwc3-qcom-legacy; do
+    if lsmod 2>/dev/null | grep -q "^$m "; then
+        echo "  $m: LOADED"
+    else
+        echo "  $m: not loaded"
+    fi
+done
+
+echo ""
+echo "--- ALSA Cards ---"
+cat /proc/asound/cards
+echo ""
+aplay -l 2>/dev/null | awk '{print "  " $0}'
+echo ""
+arecord -l 2>/dev/null | awk '{print "  " $0}'
+
+echo ""
+echo "--- ALSA MIDI ---"
+echo "  Raw MIDI devices:"
+ls /dev/snd/midi* 2>/dev/null | awk '{print "    " $0}' || echo "    (none)"
+echo "  ALSA sequencer:"
+aconnect -lio 2>/dev/null | awk '{print "    " $0}' || echo "    (none)"
+echo "  amidi ports:"
+amidi -l 2>/dev/null | awk '{print "    " $0}' || echo "    (none)"
+
+echo ""
+echo "--- Pd Status ---"
+pd_pid=$(pgrep -x pd 2>/dev/null || echo "")
+if [ -n "$pd_pid" ]; then
+    echo "  PID:        $pd_pid"
+    echo "  Args:       $(tr '\0' ' ' < /proc/$pd_pid/cmdline 2>/dev/null)"
+    echo "  Uptime:     $(ps -o etime= -p $pd_pid 2>/dev/null | xargs)"
+    echo "  CPU:        $(ps -o %cpu= -p $pd_pid 2>/dev/null | xargs)%"
+    echo "  MEM:        $(ps -o %mem= -p $pd_pid 2>/dev/null | xargs)%"
+else
+    echo "  Pd: not running"
+fi
+for svc in pd-synth-auto pd-synth pd-synth-i2s usb-role-detect usb-gadget-audio; do
+    state=$(systemctl is-active "$svc" 2>/dev/null || echo '(not found)')
+    enabled=$(systemctl is-enabled "$svc" 2>/dev/null || echo '(not found)')
+    echo "  $svc: $state (enabled: $enabled)"
+done
+
+echo ""
+echo "--- dmesg (USB/gadget errors) ---"
+dmesg -l err,warn 2>/dev/null | grep -iE 'usb|gadget|uac1|midi|pd|audio|dwc3' | tail -20 | awk '{print "  " $0}'
+echo ""
+dmesg 2>/dev/null | grep -i 'failed to start\|incorrect sample\|couldn.t find.*UDC\|probe.*failed' | tail -5 | awk '{print "  " $0}'