UsbManager: New APIs for USB accessories
USB accessories are peripherals that connect to android devices as a USB host.
When connected, the accessory will first identify itself to the android device
by sending manufacturer, product, accessory type and version strings
to the device, and then request the device to enter USB accessory mode.
The device will then enable the USB accessory kernel driver and disable
all other USB functionality except possibly adb
(adb can be used while the android device is connected to the PC
and the PC is running software that emulates a USB accessory)
The class android.hardware.UsbAccessory is used to describe the
currently attached USB accessory.
UsbAccessory contains the manufacturer, product, accessory type
and version strings to identify the accessory.
The accessory can be opened as a ParcelFileDescriptor, which can be used
to communicate with the accessory over two bulk endpoints.
The Intents UsbManager.USB_ACCESSORY_ATTACHED and
UsbManager.USB_ACCESSORY_DETACHED are broadcast when accessories are
connected and disconnected to the device. The USB_ACCESSORY_ATTACHED
contains a UsbAccessory object for the attached accessory as an extra.
The Intent also contains string extras for the manufacturer, product,
accessory type and version strings to allow filtering on these strings.
Change-Id: Ie77cbf51814a4aa44a6b1e62673bfe4c6aa81755
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/services/java/com/android/server/UsbService.java b/services/java/com/android/server/UsbService.java
index 460fd4d..af4c425 100644
--- a/services/java/com/android/server/UsbService.java
+++ b/services/java/com/android/server/UsbService.java
@@ -20,6 +20,7 @@
import android.content.Context;
import android.content.Intent;
import android.hardware.IUsbManager;
+import android.hardware.UsbAccessory;
import android.hardware.UsbConstants;
import android.hardware.UsbDevice;
import android.hardware.UsbEndpoint;
@@ -78,18 +79,63 @@
private int mLastConfiguration = -1;
// lists of enabled and disabled USB functions (for USB device mode)
+ // synchronize on mEnabledFunctions when using either of these lists
private final ArrayList<String> mEnabledFunctions = new ArrayList<String>();
private final ArrayList<String> mDisabledFunctions = new ArrayList<String>();
+ // contains all connected USB devices (for USB host mode)
private final HashMap<String,UsbDevice> mDevices = new HashMap<String,UsbDevice>();
// USB busses to exclude from USB host support
private final String[] mHostBlacklist;
private boolean mSystemReady;
+ private UsbAccessory mCurrentAccessory;
private final Context mContext;
+ private final void functionEnabled(String function, boolean enabled) {
+ synchronized (mEnabledFunctions) {
+ if (enabled) {
+ if (!mEnabledFunctions.contains(function)) {
+ mEnabledFunctions.add(function);
+ }
+ mDisabledFunctions.remove(function);
+ } else {
+ if (!mDisabledFunctions.contains(function)) {
+ mDisabledFunctions.add(function);
+ }
+ mEnabledFunctions.remove(function);
+ }
+ }
+
+ if (enabled && UsbManager.USB_FUNCTION_ACCESSORY.equals(function)) {
+ String[] strings = nativeGetAccessoryStrings();
+ if (strings != null) {
+ Log.d(TAG, "entering USB accessory mode");
+ mCurrentAccessory = new UsbAccessory(strings);
+ Intent intent = new Intent(UsbManager.ACTION_USB_ACCESSORY_ATTACHED);
+ intent.putExtra(UsbManager.EXTRA_ACCESSORY, mCurrentAccessory);
+ // add strings as separate extras to allow filtering
+ if (strings[0] != null) {
+ intent.putExtra(UsbManager.EXTRA_ACCESSORY_MANUFACTURER, strings[0]);
+ }
+ if (strings[1] != null) {
+ intent.putExtra(UsbManager.EXTRA_ACCESSORY_PRODUCT, strings[1]);
+ }
+ if (strings[2] != null) {
+ intent.putExtra(UsbManager.EXTRA_ACCESSORY_TYPE, strings[2]);
+ }
+ if (strings[3] != null) {
+ intent.putExtra(UsbManager.EXTRA_ACCESSORY_VERSION, strings[3]);
+ }
+ mContext.sendBroadcast(intent);
+ } else {
+ Log.e(TAG, "nativeGetAccessoryStrings failed");
+ }
+ }
+ }
+
private final UEventObserver mUEventObserver = new UEventObserver() {
@Override
public void onUEvent(UEventObserver.UEvent event) {
@@ -127,17 +173,7 @@
// Note: we do not broadcast a change when a function is enabled or disabled.
// We just record the state change for the next broadcast.
boolean enabled = "1".equals(enabledStr);
- if (enabled) {
- if (!mEnabledFunctions.contains(function)) {
- mEnabledFunctions.add(function);
- }
- mDisabledFunctions.remove(function);
- } else {
- if (!mDisabledFunctions.contains(function)) {
- mDisabledFunctions.add(function);
- }
- mEnabledFunctions.remove(function);
- }
+ functionEnabled(function, enabled);
}
}
}
@@ -182,18 +218,20 @@
return;
try {
- File[] files = new File(USB_COMPOSITE_CLASS_PATH).listFiles();
- for (int i = 0; i < files.length; i++) {
- File file = new File(files[i], "enable");
- FileReader reader = new FileReader(file);
- int len = reader.read(buffer, 0, 1024);
- reader.close();
- int value = Integer.valueOf((new String(buffer, 0, len)).trim());
- String functionName = files[i].getName();
- if (value == 1) {
- mEnabledFunctions.add(functionName);
- } else {
- mDisabledFunctions.add(functionName);
+ synchronized (mEnabledFunctions) {
+ File[] files = new File(USB_COMPOSITE_CLASS_PATH).listFiles();
+ for (int i = 0; i < files.length; i++) {
+ File file = new File(files[i], "enable");
+ FileReader reader = new FileReader(file);
+ int len = reader.read(buffer, 0, 1024);
+ reader.close();
+ int value = Integer.valueOf((new String(buffer, 0, len)).trim());
+ String functionName = files[i].getName();
+ if (value == 1) {
+ mEnabledFunctions.add(functionName);
+ } else {
+ mDisabledFunctions.add(functionName);
+ }
}
}
} catch (FileNotFoundException e) {
@@ -359,19 +397,32 @@
mContext.enforceCallingOrSelfPermission(android.Manifest.permission.ACCESS_USB, null);
if (mDevices.get(deviceName) == null) {
// if it is not in mDevices, it either does not exist or is blacklisted
- throw new IllegalArgumentException("device " + deviceName + " does not exist or is restricted");
+ throw new IllegalArgumentException(
+ "device " + deviceName + " does not exist or is restricted");
}
return nativeOpenDevice(deviceName);
}
+ public UsbAccessory getCurrentAccessory() {
+ mContext.enforceCallingOrSelfPermission(android.Manifest.permission.ACCESS_USB, null);
+ return mCurrentAccessory;
+ }
+
+ public ParcelFileDescriptor openAccessory() {
+ mContext.enforceCallingOrSelfPermission(android.Manifest.permission.ACCESS_USB, null);
+ return nativeOpenAccessory();
+ }
+
private final Handler mHandler = new Handler() {
private void addEnabledFunctions(Intent intent) {
+ synchronized (mEnabledFunctions) {
// include state of all USB functions in our extras
- for (int i = 0; i < mEnabledFunctions.size(); i++) {
- intent.putExtra(mEnabledFunctions.get(i), UsbManager.USB_FUNCTION_ENABLED);
- }
- for (int i = 0; i < mDisabledFunctions.size(); i++) {
- intent.putExtra(mDisabledFunctions.get(i), UsbManager.USB_FUNCTION_DISABLED);
+ for (int i = 0; i < mEnabledFunctions.size(); i++) {
+ intent.putExtra(mEnabledFunctions.get(i), UsbManager.USB_FUNCTION_ENABLED);
+ }
+ for (int i = 0; i < mDisabledFunctions.size(); i++) {
+ intent.putExtra(mDisabledFunctions.get(i), UsbManager.USB_FUNCTION_DISABLED);
+ }
}
}
@@ -381,6 +432,26 @@
case MSG_UPDATE:
synchronized (this) {
if (mConnected != mLastConnected || mConfiguration != mLastConfiguration) {
+ if (mConnected == 0 && mCurrentAccessory != null) {
+ // turn off accessory mode when we are disconnected
+ if (UsbManager.setFunctionEnabled(
+ UsbManager.USB_FUNCTION_ACCESSORY, false)) {
+ Log.d(TAG, "exited USB accessory mode");
+
+ Intent intent = new Intent(
+ UsbManager.ACTION_USB_ACCESSORY_DETACHED);
+ intent.putExtra(UsbManager.EXTRA_ACCESSORY, mCurrentAccessory);
+ mContext.sendBroadcast(intent);
+ mCurrentAccessory = null;
+
+ // this will cause an immediate reset of the USB bus,
+ // so there is no point in sending the
+ // function disabled broadcast.
+ return;
+ } else {
+ Log.e(TAG, "could not disable USB_FUNCTION_ACCESSORY");
+ }
+ }
final ContentResolver cr = mContext.getContentResolver();
if (Settings.Secure.getInt(cr,
@@ -408,4 +479,6 @@
private native void monitorUsbHostBus();
private native ParcelFileDescriptor nativeOpenDevice(String deviceName);
+ private native String[] nativeGetAccessoryStrings();
+ private native ParcelFileDescriptor nativeOpenAccessory();
}