Modify UsbDeviceManager stack to allow MtpServer to use FunctionFS drivers.

Functionfs requires MtpServer to write descriptors before the device can be
configured. This adds a new configure call that will occur only when
functions are changed (new argument added to updateUsbStateBroadcast for this)
and be called after sys.usb.config is changed but before the waitForState
call to ensure compatibility with configfs devices.

Bug: 30976142
Change-Id: I7e94a5847d3b19c0fd75139e1b15a3f2a1cea01d
Test: Manual

4 files changed, 38 insertions, 17 deletions

diff --git a/core/java/android/hardware/usb/UsbManager.java b/core/java/android/hardware/usb/UsbManager.java
index 3df57bcb704f..ee646c087608 100644
--- a/core/java/android/hardware/usb/UsbManager.java
+++ b/core/java/android/hardware/usb/UsbManager.java
@@ -181,6 +181,14 @@ public class UsbManager {
     public static final String USB_DATA_UNLOCKED = "unlocked";
 
     /**
+     * Boolean extra indicating whether the intent represents a change in the usb
+     * configuration (as opposed to a state update).
+     *
+     * {@hide}
+     */
+    public static final String USB_CONFIG_CHANGED = "config_changed";
+
+    /**
      * A placeholder indicating that no USB function is being specified.
      * Used to distinguish between selecting no function vs. the default function in
      * {@link #setCurrentFunction(String)}.
diff --git a/media/java/android/mtp/MtpServer.java b/media/java/android/mtp/MtpServer.java
index 61fbfb902d0d..3c2ea58e7a2e 100644
--- a/media/java/android/mtp/MtpServer.java
+++ b/media/java/android/mtp/MtpServer.java
@@ -67,6 +67,11 @@ public class MtpServer implements Runnable {
         native_remove_storage(storage.getStorageId());
     }
 
+    public static void configure(boolean usePtp) {
+        native_configure(usePtp);
+    }
+
+    public static native final void native_configure(boolean usePtp);
     private native final void native_setup(MtpDatabase database, boolean usePtp);
     private native final void native_run();
     private native final void native_cleanup();
diff --git a/media/jni/android_mtp_MtpServer.cpp b/media/jni/android_mtp_MtpServer.cpp
index d13187c39846..afd3082ec51b 100644
--- a/media/jni/android_mtp_MtpServer.cpp
+++ b/media/jni/android_mtp_MtpServer.cpp
@@ -56,17 +56,16 @@ static inline MtpServer* getMtpServer(JNIEnv *env, jobject thiz) {
     return (MtpServer*)env->GetLongField(thiz, field_MtpServer_nativeContext);
 }
 
+static void android_mtp_configure(JNIEnv *, jobject, jboolean usePtp) {
+    MtpServer::configure(usePtp);
+}
+
 static void
 android_mtp_MtpServer_setup(JNIEnv *env, jobject thiz, jobject javaDatabase, jboolean usePtp)
 {
-    int fd = open("/dev/mtp_usb", O_RDWR);
-    if (fd >= 0) {
-        MtpServer* server = new MtpServer(fd, getMtpDatabase(env, javaDatabase),
-                usePtp, AID_MEDIA_RW, 0664, 0775);
-        env->SetLongField(thiz, field_MtpServer_nativeContext, (jlong)server);
-    } else {
-        ALOGE("could not open MTP driver, errno: %d", errno);
-    }
+    MtpServer* server = new MtpServer(getMtpDatabase(env, javaDatabase),
+            usePtp, AID_MEDIA_RW, 0664, 0775);
+    env->SetLongField(thiz, field_MtpServer_nativeContext, (jlong)server);
 }
 
 static void
@@ -180,6 +179,7 @@ android_mtp_MtpServer_remove_storage(JNIEnv *env, jobject thiz, jint storageId)
 // ----------------------------------------------------------------------------
 
 static const JNINativeMethod gMethods[] = {
+    {"native_configure",              "(Z)V",  (void *)android_mtp_configure},
     {"native_setup",                "(Landroid/mtp/MtpDatabase;Z)V",
                                             (void *)android_mtp_MtpServer_setup},
     {"native_run",                  "()V",  (void *)android_mtp_MtpServer_run},
diff --git a/services/usb/java/com/android/server/usb/UsbDeviceManager.java b/services/usb/java/com/android/server/usb/UsbDeviceManager.java
index 15a1e760f528..b3f5630b8e25 100644
--- a/services/usb/java/com/android/server/usb/UsbDeviceManager.java
+++ b/services/usb/java/com/android/server/usb/UsbDeviceManager.java
@@ -351,8 +351,6 @@ public class UsbDeviceManager {
                             UsbManager.removeFunction(persisted, UsbManager.USB_FUNCTION_MTP));
                 }
 
-                setEnabledFunctions(null, false, false);
-
                 String state = FileUtils.readTextFile(new File(STATE_PATH), 0, null).trim();
                 updateState(state);
 
@@ -446,13 +444,12 @@ public class UsbDeviceManager {
             return false;
         }
 
-        private boolean setUsbConfig(String config) {
+        private void setUsbConfig(String config) {
             if (DEBUG) Slog.d(TAG, "setUsbConfig(" + config + ")");
             // set the new configuration
             // we always set it due to b/23631400, where adbd was getting killed
             // and not restarted due to property timeouts on some devices
             SystemProperties.set(USB_CONFIG_PROPERTY, config);
-            return waitForState(config);
         }
 
         private void setAdbEnabled(boolean enable) {
@@ -547,8 +544,18 @@ public class UsbDeviceManager {
                 // Kick the USB stack to close existing connections.
                 setUsbConfig(UsbManager.USB_FUNCTION_NONE);
 
+                if (!waitForState(UsbManager.USB_FUNCTION_NONE)) {
+                    Slog.e(TAG, "Failed to kick USB config");
+                    return false;
+                }
+
                 // Set the new USB configuration.
-                if (!setUsbConfig(functions)) {
+                setUsbConfig(functions);
+
+                // Start up dependent services.
+                updateUsbStateBroadcastIfNeeded(true);
+
+                if (!waitForState(functions)) {
                     Slog.e(TAG, "Failed to switch USB config to " + functions);
                     return false;
                 }
@@ -631,7 +638,7 @@ public class UsbDeviceManager {
             return false;
         }
 
-        private void updateUsbStateBroadcastIfNeeded() {
+        private void updateUsbStateBroadcastIfNeeded(boolean configChanged) {
             // send a sticky broadcast containing current USB state
             Intent intent = new Intent(UsbManager.ACTION_USB_STATE);
             intent.addFlags(Intent.FLAG_RECEIVER_REPLACE_PENDING
@@ -640,6 +647,7 @@ public class UsbDeviceManager {
             intent.putExtra(UsbManager.USB_HOST_CONNECTED, mHostConnected);
             intent.putExtra(UsbManager.USB_CONFIGURED, mConfigured);
             intent.putExtra(UsbManager.USB_DATA_UNLOCKED, isUsbTransferAllowed() && mUsbDataUnlocked);
+            intent.putExtra(UsbManager.USB_CONFIG_CHANGED, configChanged);
 
             if (mCurrentFunctions != null) {
                 String[] functions = mCurrentFunctions.split(",");
@@ -737,7 +745,7 @@ public class UsbDeviceManager {
                         setEnabledFunctions(null, false, false);
                     }
                     if (mBootCompleted) {
-                        updateUsbStateBroadcastIfNeeded();
+                        updateUsbStateBroadcastIfNeeded(false);
                         updateUsbFunctions();
                     }
                     break;
@@ -749,7 +757,7 @@ public class UsbDeviceManager {
                     args.recycle();
                     updateUsbNotification();
                     if (mBootCompleted) {
-                        updateUsbStateBroadcastIfNeeded();
+                        updateUsbStateBroadcastIfNeeded(false);
                     }
                     break;
                 case MSG_ENABLE_ADB:
@@ -765,11 +773,11 @@ public class UsbDeviceManager {
                 case MSG_SYSTEM_READY:
                     updateUsbNotification();
                     updateAdbNotification();
-                    updateUsbStateBroadcastIfNeeded();
                     updateUsbFunctions();
                     break;
                 case MSG_BOOT_COMPLETED:
                     mBootCompleted = true;
+                    setEnabledFunctions(null, false, false);
                     if (mCurrentAccessory != null) {
                         getCurrentSettings().accessoryAttached(mCurrentAccessory);
                     }