Add ADB over USB support (#417)

* figuring out adb device agent

* start adbd service in comma.sh

* implement thundercomm adb implementation

* UDC check

* setup_gadget_mode

* usb gadget created

* adb device shown

* android.rules

* check functionfs mount + add serial number

* 250 maxPower

* lil more

* fix

* doesn't seem to be needed

* cleanup

---------

Co-authored-by: Adeeb Shihadeh <adeebshihadeh@gmail.com>

userspace/base_setup.sh

@@ -113,6 +113,7 @@ rm -rf /var/lib/apt/lists/*
 # Create dirs
 mkdir /data && chown $USERNAME:$USERNAME /data
 mkdir /persist && chown $USERNAME:$USERNAME /persist
+mkdir /config && chown root:root /config
 
 # Disable pstore service that moves files out of /sys/fs/pstore
 systemctl disable systemd-pstore.service

userspace/files/adb-param-watcher.path

@@ -0,0 +1,5 @@
+[Path]
+PathModified=/data/params/d/AdbEnabled
+
+[Install]
+WantedBy=multi-user.target

userspace/files/adb-param-watcher.service

@@ -0,0 +1,10 @@
+[Unit]
+Description=ADB param watcher
+After=network.target
+
+[Service]
+Type=oneshot
+ExecStart=/usr/comma/set_adb.sh
+
+[Install]
+WantedBy=multi-user.target

userspace/services.sh

@@ -21,6 +21,8 @@ systemctl enable power_drop_monitor.service
 systemctl enable brightnessd.service
 systemctl enable ssh-param-watcher.path
 systemctl enable ssh-param-watcher.service
+systemctl enable adb-param-watcher.path
+systemctl enable adb-param-watcher.service
 systemctl enable logrotate-hourly.timer
 
 # Disable some of our services

userspace/usr/comma/comma.sh

@@ -33,10 +33,12 @@ handle_setup_keys () {
       ln -s /data/params/d_tmp /data/params/d
     fi
 
+    echo -n 1 > /data/params/d/AdbEnabled
     echo -n 1 > /data/params/d/SshEnabled
     cp /usr/comma/setup_keys /data/params/d/GithubSshKeys
   elif [[ -e /data/params/d/GithubSshKeys && -e /data/continue.sh ]]; then
     if cmp -s /data/params/d/GithubSshKeys /usr/comma/setup_keys; then
+      rm /data/params/d/AdbEnabled
       rm /data/params/d/SshEnabled
       rm /data/params/d/GithubSshKeys
     fi

userspace/usr/comma/set_adb.sh

@@ -0,0 +1,66 @@
+#!/bin/bash
+
+setup_gadget() {
+  # Check if /config is already mounted
+  if ! mountpoint -q /config; then
+    sudo mount -t configfs none /config
+  else
+    echo "/config is already mounted."
+  fi
+
+  # Create USB gadget directory structure
+  sudo mkdir -p /config/usb_gadget/g1
+  cd /config/usb_gadget/g1
+  sudo mkdir -p strings/0x409
+  sudo mkdir -p configs/c.1/strings/0x409
+  sudo mkdir -p functions/ncm.0
+
+  # Set Vendor and Product ID
+  echo 0x04D8 | sudo tee idVendor
+  echo 0x1234 | sudo tee idProduct
+
+  # Set strings
+  echo "$(cat /proc/cmdline | sed -e 's/^.*androidboot.serialno=//' -e 's/ .*$//')" | sudo tee strings/0x409/serialnumber
+  echo "comma.ai" | sudo tee strings/0x409/manufacturer
+  echo "Linux USB Gadget" | sudo tee strings/0x409/product
+  echo 250 | sudo tee configs/c.1/MaxPower
+
+  # Create ADB function
+  sudo mkdir -p functions/ffs.adb
+  sudo mkdir -p /dev/usb-ffs/adb
+  if ! mountpoint -q /dev/usb-ffs/adb; then
+    sudo mount -t functionfs adb /dev/usb-ffs/adb
+  else
+    echo "/dev/usb-ffs/adb is already mounted"
+  fi
+  # Link both functions to configuration
+  echo "NCM+ADB" | sudo tee configs/c.1/strings/0x409/configuration
+  sudo rm -f configs/c.1/ncm.0
+  sudo rm -f configs/c.1/ffs.adb
+  sudo ln -s functions/ncm.0 configs/c.1/
+  sudo ln -s functions/ffs.adb configs/c.1/
+}
+
+start_gadget() {
+  cd /config/usb_gadget/g1
+  echo "a600000.dwc3" | sudo tee UDC
+}
+
+stop_gadget() {
+  cd /config/usb_gadget/g1
+  echo "" | sudo tee UDC
+}
+
+ADB_PARAM="/data/params/d/AdbEnabled"
+if [ -f "$ADB_PARAM" ] && [ "$(< $ADB_PARAM)" == "1" ]; then
+  echo "Enabling ADB"
+
+  setup_gadget
+  systemctl start adbd
+  sleep 1
+  start_gadget
+else
+  echo "Disabling ADB"
+  systemctl stop adbd
+  stop_gadget
+fi