usb: add gadget hal

* Copy from hardware/interfaces/usb/gadget/1.2/default with udc
  path changed and service renamed for Raspberry Pi.

usb/service.cpp

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ * Copyright (C) 2023 KonstaKANG
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "android.hardware.usb.gadget@1.2-service.rpi"
+
+#include <hidl/HidlTransportSupport.h>
+#include "UsbGadget.h"
+
+using android::sp;
+
+// libhwbinder:
+using android::hardware::configureRpcThreadpool;
+using android::hardware::joinRpcThreadpool;
+
+// Generated HIDL files
+using android::hardware::usb::gadget::V1_2::IUsbGadget;
+using android::hardware::usb::gadget::V1_2::implementation::UsbGadget;
+
+using android::OK;
+using android::status_t;
+
+int main() {
+    configureRpcThreadpool(1, true /*callerWillJoin*/);
+
+    android::sp<IUsbGadget> service = new UsbGadget();
+
+    status_t status = service->registerAsService();
+
+    if (status != OK) {
+        ALOGE("Cannot register USB Gadget HAL service");
+        return 1;
+    }
+
+    ALOGI("USB Gadget HAL Ready.");
+    joinRpcThreadpool();
+    // Under noraml cases, execution will not reach this line.
+    ALOGI("USB Gadget HAL failed to join thread pool.");
+    return 1;
+}