Usb Gadget hal implementation for crosshatch

(cherry-pick of commit: 5e309b924830644827182e039e915e5ba314a81f)

Bug: 77927124
Test: Tested USB gadget configurations and verified
that they enumerated.

Change-Id: I7be5f1df3a5e9edb8f7c60b82e48c31ed9e5cdde
Signed-off-by: rickyniu <rickyniu@google.com>

7 files changed, 614 insertions, 7 deletions

diff --git a/usb/Android.bp b/usb/Android.bp
index a12150b..511af20 100644
--- a/usb/Android.bp
+++ b/usb/Android.bp
@@ -16,8 +16,7 @@ cc_binary {
     name: "android.hardware.usb@1.1-service.crosshatch",
     relative_install_path: "hw",
     init_rc: ["android.hardware.usb@1.1-service.crosshatch.rc"],
-    srcs: ["service.cpp", "Usb.cpp"],
-    cflags: ["-Wall", "-Werror"],
+    srcs: ["service.cpp", "Usb.cpp", "UsbGadget.cpp"],
     shared_libs: [
         "libbase",
         "libhidlbase",
@@ -27,6 +26,7 @@ cc_binary {
         "libhardware",
         "android.hardware.usb@1.0",
         "android.hardware.usb@1.1",
+	"android.hardware.usb.gadget@1.0",
         "libcutils",
     ],
     proprietary: true,
diff --git a/usb/Usb.cpp b/usb/Usb.cpp
index 2fee924..f0ecedd 100644
--- a/usb/Usb.cpp
+++ b/usb/Usb.cpp
@@ -212,7 +212,7 @@ Usb::Usb()
 
 
 Return<void> Usb::switchRole(const hidl_string &portName,
-                             const PortRole &newRole) {
+                             const V1_0::PortRole &newRole) {
   std::string filename =
       appendRoleNodeHelper(std::string(portName.c_str()), newRole.type);
   std::string written;
diff --git a/usb/Usb.h b/usb/Usb.h
index 78be2f9..09bfdf9 100644
--- a/usb/Usb.h
+++ b/usb/Usb.h
@@ -42,7 +42,7 @@ using ::android::sp;
 struct Usb : public IUsb {
     Usb();
 
-    Return<void> switchRole(const hidl_string& portName, const PortRole& role) override;
+    Return<void> switchRole(const hidl_string& portName, const V1_0::PortRole& role) override;
     Return<void> setCallback(const sp<V1_0::IUsbCallback>& callback) override;
     Return<void> queryPortStatus() override;
 
diff --git a/usb/UsbGadget.cpp b/usb/UsbGadget.cpp
new file mode 100644
index 0000000..5c1fb2d
--- /dev/null
+++ b/usb/UsbGadget.cpp
@@ -0,0 +1,497 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * 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@1.0-service.crosshatch"
+
+#include "UsbGadget.h"
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/inotify.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+constexpr int BUFFER_SIZE = 512;
+constexpr int MAX_FILE_PATH_LENGTH = 256;
+constexpr int EPOLL_EVENTS = 10;
+constexpr bool DEBUG = false;
+constexpr int DISCONNECT_WAIT_US = 10000;
+
+#define GADGET_PATH "/config/usb_gadget/g1/"
+#define PULLUP_PATH GADGET_PATH "UDC"
+#define GADGET_NAME "a600000.dwc3"
+#define PERSISTENT_BOOT_MODE "ro.bootmode"
+#define VENDOR_ID_PATH GADGET_PATH "idVendor"
+#define PRODUCT_ID_PATH GADGET_PATH "idProduct"
+#define DEVICE_CLASS_PATH GADGET_PATH "bDeviceClass"
+#define DEVICE_SUB_CLASS_PATH GADGET_PATH "bDeviceSubClass"
+#define DEVICE_PROTOCOL_PATH GADGET_PATH "bDeviceProtocol"
+#define DESC_USE_PATH GADGET_PATH "os_desc/use"
+#define OS_DESC_PATH GADGET_PATH "os_desc/b.1"
+#define CONFIG_PATH GADGET_PATH "configs/b.1/"
+#define FUNCTIONS_PATH GADGET_PATH "functions/"
+#define FUNCTION_NAME "function"
+#define FUNCTION_PATH CONFIG_PATH FUNCTION_NAME
+#define RNDIS_PATH FUNCTIONS_PATH "gsi.rndis"
+
+namespace android {
+namespace hardware {
+namespace usb {
+namespace gadget {
+namespace V1_0 {
+namespace implementation {
+
+volatile bool gadgetPullup;
+
+// Used for debug.
+static void displayInotifyEvent(struct inotify_event *i) {
+  ALOGE("    wd =%2d; ", i->wd);
+  if (i->cookie > 0) ALOGE("cookie =%4d; ", i->cookie);
+
+  ALOGE("mask = ");
+  if (i->mask & IN_ACCESS) ALOGE("IN_ACCESS ");
+  if (i->mask & IN_ATTRIB) ALOGE("IN_ATTRIB ");
+  if (i->mask & IN_CLOSE_NOWRITE) ALOGE("IN_CLOSE_NOWRITE ");
+  if (i->mask & IN_CLOSE_WRITE) ALOGE("IN_CLOSE_WRITE ");
+  if (i->mask & IN_CREATE) ALOGE("IN_CREATE ");
+  if (i->mask & IN_DELETE) ALOGE("IN_DELETE ");
+  if (i->mask & IN_DELETE_SELF) ALOGE("IN_DELETE_SELF ");
+  if (i->mask & IN_IGNORED) ALOGE("IN_IGNORED ");
+  if (i->mask & IN_ISDIR) ALOGE("IN_ISDIR ");
+  if (i->mask & IN_MODIFY) ALOGE("IN_MODIFY ");
+  if (i->mask & IN_MOVE_SELF) ALOGE("IN_MOVE_SELF ");
+  if (i->mask & IN_MOVED_FROM) ALOGE("IN_MOVED_FROM ");
+  if (i->mask & IN_MOVED_TO) ALOGE("IN_MOVED_TO ");
+  if (i->mask & IN_OPEN) ALOGE("IN_OPEN ");
+  if (i->mask & IN_Q_OVERFLOW) ALOGE("IN_Q_OVERFLOW ");
+  if (i->mask & IN_UNMOUNT) ALOGE("IN_UNMOUNT ");
+  ALOGE("\n");
+
+  if (i->len > 0) ALOGE("        name = %s\n", i->name);
+}
+
+static void *monitorFfs(void *param) {
+  UsbGadget *usbGadget = (UsbGadget *)param;
+  char buf[BUFFER_SIZE];
+  bool writeUdc = true, stopMonitor = false;
+  struct epoll_event events[EPOLL_EVENTS];
+
+  bool descriptorWritten = true;
+  for (int i = 0; i < static_cast<int>(usbGadget->mEndpointList.size()); i++) {
+    if (access(usbGadget->mEndpointList.at(i).c_str(), R_OK)) {
+      descriptorWritten = false;
+      break;
+    }
+  }
+
+  // notify here if the endpoints are already present.
+  if (descriptorWritten && !!WriteStringToFile(GADGET_NAME, PULLUP_PATH)) {
+    lock_guard<mutex> lock(usbGadget->mLock);
+    usbGadget->mCurrentUsbFunctionsApplied = true;
+    gadgetPullup = true;
+    usbGadget->mCv.notify_all();
+  }
+
+  while (!stopMonitor) {
+    int nrEvents = epoll_wait(usbGadget->mEpollFd, events, EPOLL_EVENTS, -1);
+    if (nrEvents <= 0) {
+      ALOGE("epoll wait did not return descriptor number");
+      continue;
+    }
+
+    for (int i = 0; i < nrEvents; i++) {
+      ALOGI("event=%u on fd=%d\n", events[i].events, events[i].data.fd);
+
+      if (events[i].data.fd == usbGadget->mInotifyFd) {
+        // Process all of the events in buffer returned by read().
+        int numRead = read(usbGadget->mInotifyFd, buf, BUFFER_SIZE);
+        for (char *p = buf; p < buf + numRead;) {
+          struct inotify_event *event = (struct inotify_event *)p;
+          if (DEBUG) displayInotifyEvent(event);
+
+          p += sizeof(struct inotify_event) + event->len;
+
+          bool descriptorPresent = true;
+          for (int j = 0; j < static_cast<int>(usbGadget->mEndpointList.size());
+               j++) {
+            if (access(usbGadget->mEndpointList.at(j).c_str(), R_OK)) {
+              if (DEBUG)
+                ALOGI("%s absent", usbGadget->mEndpointList.at(j).c_str());
+              descriptorPresent = false;
+              break;
+            }
+          }
+
+          if (!descriptorPresent && !writeUdc) {
+            if (DEBUG) ALOGI("endpoints not up");
+            writeUdc = true;
+          } else if (descriptorPresent && writeUdc &&
+                     !!WriteStringToFile(GADGET_NAME, PULLUP_PATH)) {
+            lock_guard<mutex> lock(usbGadget->mLock);
+            usbGadget->mCurrentUsbFunctionsApplied = true;
+            ALOGI("GADGET pulled up");
+            writeUdc = false;
+            gadgetPullup = true;
+            // notify the main thread to signal userspace.
+            usbGadget->mCv.notify_all();
+          }
+        }
+      } else {
+        uint64_t flag;
+        read(usbGadget->mEventFd, &flag, sizeof(flag));
+        if (flag == 100) {
+          stopMonitor = true;
+          break;
+        }
+      }
+    }
+  }
+  return NULL;
+}
+
+UsbGadget::UsbGadget() {
+  if (access(OS_DESC_PATH, R_OK) != 0)
+    ALOGE("configfs setup not done yet");
+}
+
+static int unlinkFunctions(const char *path) {
+  DIR *config = opendir(path);
+  struct dirent *function;
+  char filepath[MAX_FILE_PATH_LENGTH];
+  int ret = 0;
+
+  if (config == NULL) return -1;
+
+  // d_type does not seems to be supported in /config
+  // so filtering by name.
+  while (((function = readdir(config)) != NULL)) {
+    if ((strstr(function->d_name, FUNCTION_NAME) == NULL)) continue;
+    // build the path for each file in the folder.
+    sprintf(filepath, "%s/%s", path, function->d_name);
+    ret = remove(filepath);
+    if (ret) {
+      ALOGE("Unable  remove file %s errno:%d", filepath, errno);
+      break;
+    }
+  }
+
+  closedir(config);
+  return ret;
+}
+
+static int addEpollFd(const unique_fd &epfd, const unique_fd &fd) {
+  struct epoll_event event;
+  int ret;
+
+  event.data.fd = fd;
+  event.events = EPOLLIN;
+
+  ret = epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &event);
+  if (ret) ALOGE("epoll_ctl error %d", errno);
+
+  return ret;
+}
+
+Return<void> UsbGadget::getCurrentUsbFunctions(
+    const sp<V1_0::IUsbGadgetCallback> &callback) {
+  Return<void> ret = callback->getCurrentUsbFunctionsCb(
+      mCurrentUsbFunctions, mCurrentUsbFunctionsApplied
+                                ? Status::FUNCTIONS_APPLIED
+                                : Status::FUNCTIONS_NOT_APPLIED);
+  if (!ret.isOk())
+    ALOGE("Call to getCurrentUsbFunctionsCb failed %s",
+          ret.description().c_str());
+
+  return Void();
+}
+
+V1_0::Status UsbGadget::tearDownGadget() {
+  ALOGI("setCurrentUsbFunctions None");
+
+  if (!WriteStringToFile("none", PULLUP_PATH))
+    ALOGI("Gadget cannot be pulled down");
+
+  if (!WriteStringToFile("0", DEVICE_CLASS_PATH)) return Status::ERROR;
+
+  if (!WriteStringToFile("0", DEVICE_SUB_CLASS_PATH)) return Status::ERROR;
+
+  if (!WriteStringToFile("0", DEVICE_PROTOCOL_PATH)) return Status::ERROR;
+
+  if (!WriteStringToFile("0", DESC_USE_PATH)) return Status::ERROR;
+
+  if (unlinkFunctions(CONFIG_PATH)) return Status::ERROR;
+
+  if (mMonitorCreated) {
+    uint64_t flag = 100;
+    // Stop the monitor thread by writing into signal fd.
+    write(mEventFd, &flag, sizeof(flag));
+    mMonitor->join();
+    mMonitorCreated = false;
+    ALOGI("mMonitor destroyed");
+  } else {
+    ALOGI("mMonitor not running");
+  }
+
+  mInotifyFd.reset(-1);
+  mEventFd.reset(-1);
+  mEpollFd.reset(-1);
+  mEndpointList.clear();
+  return Status::SUCCESS;
+}
+
+static int linkFunction(const char *function, int index) {
+  char functionPath[MAX_FILE_PATH_LENGTH];
+  char link[MAX_FILE_PATH_LENGTH];
+
+  sprintf(functionPath, "%s%s", FUNCTIONS_PATH, function);
+  sprintf(link, "%s%d", FUNCTION_PATH, index);
+  if (symlink(functionPath, link)) {
+    ALOGE("Cannot create symlink %s -> %s errno:%d", link, functionPath, errno);
+    return -1;
+  }
+  return 0;
+}
+
+static V1_0::Status setVidPid(const char *vid, const char *pid) {
+  if (!WriteStringToFile(vid, VENDOR_ID_PATH)) return Status::ERROR;
+
+  if (!WriteStringToFile(pid, PRODUCT_ID_PATH)) return Status::ERROR;
+
+  return Status::SUCCESS;
+}
+
+static V1_0::Status validateAndSetVidPid(uint64_t functions) {
+  V1_0::Status ret = Status::SUCCESS;
+  switch (functions) {
+    case static_cast<uint64_t>(GadgetFunction::MTP):
+      ret = setVidPid("0x18d1", "0x4ee1");
+      break;
+    case GadgetFunction::ADB | GadgetFunction::MTP:
+      ret = setVidPid("0x18d1", "0x4ee2");
+      break;
+    case static_cast<uint64_t>(GadgetFunction::RNDIS):
+      ret = setVidPid("0x18d1", "0x4ee3");
+      break;
+    case GadgetFunction::ADB | GadgetFunction::RNDIS:
+      ret = setVidPid("0x18d1", "0x4ee4");
+      break;
+    case static_cast<uint64_t>(GadgetFunction::PTP):
+      ret = setVidPid("0x18d1", "0x4ee5");
+      break;
+    case GadgetFunction::ADB | GadgetFunction::PTP:
+      ret = setVidPid("0x18d1", "0x4ee6");
+      break;
+    case static_cast<uint64_t>(GadgetFunction::ADB):
+      ret = setVidPid("0x18d1", "0x4ee7");
+      break;
+    case static_cast<uint64_t>(GadgetFunction::MIDI):
+      ret = setVidPid("0x18d1", "0x4ee8");
+      break;
+    case GadgetFunction::ADB | GadgetFunction::MIDI:
+      ret = setVidPid("0x18d1", "0x4ee9");
+      break;
+    case static_cast<uint64_t>(GadgetFunction::ACCESSORY):
+      ret = setVidPid("0x18d1", "0x2d00");
+      break;
+    case GadgetFunction::ADB | GadgetFunction::ACCESSORY:
+      ret = setVidPid("0x18d1", "0x2d01");
+      break;
+    default:
+      ALOGE("Combination not supported");
+      ret = Status::CONFIGURATION_NOT_SUPPORTED;
+  }
+  return ret;
+}
+
+V1_0::Status UsbGadget::setupFunctions(
+    uint64_t functions, const sp<V1_0::IUsbGadgetCallback> &callback,
+    uint64_t timeout) {
+  std::unique_lock<std::mutex> lk(mLock);
+
+  unique_fd inotifyFd(inotify_init());
+  if (inotifyFd < 0) {
+    ALOGE("inotify init failed");
+    return Status::ERROR;
+  }
+
+  bool ffsEnabled = false;
+  int i = 0;
+  std::string bootMode = GetProperty(PERSISTENT_BOOT_MODE, "");
+
+  if (((functions & GadgetFunction::PTP) != 0) ||
+      ((functions & GadgetFunction::MTP) != 0)) {
+    ffsEnabled = true;
+    ALOGI("setCurrentUsbFunctions mtp");
+    if (!WriteStringToFile("1", DESC_USE_PATH)) return Status::ERROR;
+
+    if (inotify_add_watch(inotifyFd, "/dev/usb-ffs/mtp/", IN_ALL_EVENTS) == -1)
+      return Status::ERROR;
+
+
+    if (linkFunction("ffs.mtp", i++)) return Status::ERROR;
+
+    // Add endpoints to be monitored.
+    mEndpointList.push_back("/dev/usb-ffs/mtp/ep1");
+    mEndpointList.push_back("/dev/usb-ffs/mtp/ep2");
+    mEndpointList.push_back("/dev/usb-ffs/mtp/ep3");
+  }
+
+  if ((functions & GadgetFunction::MIDI) != 0) {
+    ALOGI("setCurrentUsbFunctions MIDI");
+    if (linkFunction("midi.gs5", i++)) return Status::ERROR;;
+  }
+
+  if ((functions & GadgetFunction::ACCESSORY) != 0) {
+    ALOGI("setCurrentUsbFunctions Accessory");
+    if (linkFunction("accessory.gs2", i++)) return Status::ERROR;
+  }
+
+  if ((functions & GadgetFunction::RNDIS) != 0) {
+    ALOGI("setCurrentUsbFunctions rndis");
+    if (linkFunction("gsi.rndis", i++)) return Status::ERROR;
+  }
+
+  if (bootMode == "usbradio") {
+    ALOGI("enable usbradio debug functions");
+    if (linkFunction("diag.diag", i++)) return Status::ERROR;
+    if (linkFunction("cser.dun.0", i++)) return Status::ERROR;
+    if (linkFunction("gsi.rmnet", i++)) return Status::ERROR;
+  }
+
+  if ((functions & GadgetFunction::ADB) != 0) {
+    ffsEnabled = true;
+    ALOGI("setCurrentUsbFunctions Adb");
+    if (inotify_add_watch(inotifyFd, "/dev/usb-ffs/adb/", IN_ALL_EVENTS) == -1)
+      return Status::ERROR;
+
+    if (linkFunction("ffs.adb", i++)) return Status::ERROR;
+    mEndpointList.push_back("/dev/usb-ffs/adb/ep1");
+    mEndpointList.push_back("/dev/usb-ffs/adb/ep2");
+    ALOGI("Service started");
+  }
+
+  // Pull up the gadget right away when there are no ffs functions.
+  if (!ffsEnabled) {
+    if (!WriteStringToFile(GADGET_NAME, PULLUP_PATH)) return Status::ERROR;
+    mCurrentUsbFunctionsApplied = true;
+    if (callback)
+      callback->setCurrentUsbFunctionsCb(functions, Status::SUCCESS);
+    return Status::SUCCESS;
+  }
+
+  unique_fd eventFd(eventfd(0, 0));
+  if (eventFd == -1) {
+    ALOGE("mEventFd failed to create %d", errno);
+    return Status::ERROR;
+  }
+
+  unique_fd epollFd(epoll_create(2));
+  if (epollFd == -1) {
+    ALOGE("mEpollFd failed to create %d", errno);
+    return Status::ERROR;
+  }
+
+  if (addEpollFd(epollFd, inotifyFd) == -1) return Status::ERROR;
+
+  if (addEpollFd(epollFd, eventFd) == -1) return Status::ERROR;
+
+  mEpollFd = move(epollFd);
+  mInotifyFd = move(inotifyFd);
+  mEventFd = move(eventFd);
+  gadgetPullup = false;
+
+  // Monitors the ffs paths to pull up the gadget when descriptors are written.
+  // Also takes of the pulling up the gadget again if the userspace process
+  // dies and restarts.
+  mMonitor = unique_ptr<thread>(new thread(monitorFfs, this));
+  mMonitorCreated = true;
+  if (DEBUG) ALOGI("Mainthread in Cv");
+
+  if (callback) {
+    if (mCv.wait_for(lk, timeout * 1ms, [] { return gadgetPullup; })) {
+      ALOGI("monitorFfs signalled true");
+    } else {
+      ALOGI("monitorFfs signalled error");
+      // continue monitoring as the descriptors might be written at a later
+      // point.
+    }
+    Return<void> ret = callback->setCurrentUsbFunctionsCb(
+        functions, gadgetPullup ? Status::SUCCESS : Status::ERROR);
+    if (!ret.isOk())
+      ALOGE("setCurrentUsbFunctionsCb error %s", ret.description().c_str());
+  }
+
+  return Status::SUCCESS;
+}
+
+Return<void> UsbGadget::setCurrentUsbFunctions(
+    uint64_t functions, const sp<V1_0::IUsbGadgetCallback> &callback,
+    uint64_t timeout) {
+  std::unique_lock<std::mutex> lk(mLockSetCurrentFunction);
+
+  mCurrentUsbFunctions = functions;
+  mCurrentUsbFunctionsApplied = false;
+
+  // Unlink the gadget and stop the monitor if running.
+  V1_0::Status status = tearDownGadget();
+  if (status != Status::SUCCESS) {
+    goto error;
+  }
+
+  // Leave the gadget pulled down to give time for the host to sense disconnect.
+  usleep(DISCONNECT_WAIT_US);
+
+  if (functions == static_cast<uint64_t>(GadgetFunction::NONE)) {
+    if (callback == NULL) return Void();
+    Return<void> ret =
+        callback->setCurrentUsbFunctionsCb(functions, Status::SUCCESS);
+    if (!ret.isOk())
+      ALOGE("Error while calling setCurrentUsbFunctionsCb %s",
+            ret.description().c_str());
+    return Void();
+  }
+
+  status = validateAndSetVidPid(functions);
+
+  if (status != Status::SUCCESS) {
+    goto error;
+  }
+
+  status = setupFunctions(functions, callback, timeout);
+  if (status != Status::SUCCESS) {
+    goto error;
+  }
+
+  ALOGI("Usb Gadget setcurrent functions called successfully");
+  return Void();
+
+error:
+  ALOGI("Usb Gadget setcurrent functions failed");
+  if (callback == NULL) return Void();
+  Return<void> ret = callback->setCurrentUsbFunctionsCb(functions, status);
+  if (!ret.isOk())
+    ALOGE("Error while calling setCurrentUsbFunctionsCb %s",
+          ret.description().c_str());
+  return Void();
+}
+}  // namespace implementation
+}  // namespace V1_0
+}  // namespace gadget
+}  // namespace usb
+}  // namespace hardware
+}  // namespace android
diff --git a/usb/UsbGadget.h b/usb/UsbGadget.h
new file mode 100644
index 0000000..ef2ea4d
--- /dev/null
+++ b/usb/UsbGadget.h
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#ifndef ANDROID_HARDWARE_USB_GADGET_V1_0_USBGADGET_H
+#define ANDROID_HARDWARE_USB_GADGET_V1_0_USBGADGET_H
+
+#include <android-base/file.h>
+#include <android-base/properties.h>
+#include <android-base/unique_fd.h>
+#include <android/hardware/usb/gadget/1.0/IUsbGadget.h>
+#include <hidl/MQDescriptor.h>
+#include <hidl/Status.h>
+#include <sys/epoll.h>
+#include <sys/eventfd.h>
+#include <thread>
+#include <utils/Log.h>
+#include <chrono>
+#include <condition_variable>
+#include <mutex>
+
+namespace android {
+namespace hardware {
+namespace usb {
+namespace gadget {
+namespace V1_0 {
+namespace implementation {
+
+using ::android::sp;
+using ::android::base::GetProperty;
+using ::android::base::unique_fd;
+using ::android::base::WriteStringToFile;
+using ::android::hardware::hidl_array;
+using ::android::hardware::hidl_memory;
+using ::android::hardware::hidl_string;
+using ::android::hardware::hidl_vec;
+using ::android::hardware::Return;
+using ::android::hardware::Void;
+using ::std::lock_guard;
+using ::std::move;
+using ::std::mutex;
+using ::std::string;
+using ::std::thread;
+using ::std::unique_ptr;
+using ::std::vector;
+using namespace std::chrono_literals;
+
+struct UsbGadget : public IUsbGadget {
+  UsbGadget();
+  unique_fd mInotifyFd;
+  unique_fd mEventFd;
+  unique_fd mEpollFd;
+
+  unique_ptr<thread> mMonitor;
+  volatile bool mMonitorCreated;
+  vector<string> mEndpointList;
+  // protects the CV.
+  std::mutex mLock;
+  std::condition_variable mCv;
+
+  // Makes sure that only one request is processed at a time.
+  std::mutex mLockSetCurrentFunction;
+  uint64_t mCurrentUsbFunctions;
+  bool mCurrentUsbFunctionsApplied;
+
+  Return<void> setCurrentUsbFunctions(uint64_t functions,
+                                      const sp<IUsbGadgetCallback>& callback,
+                                      uint64_t timeout) override;
+
+  Return<void> getCurrentUsbFunctions(
+      const sp<IUsbGadgetCallback>& callback) override;
+
+  private:
+  Status tearDownGadget();
+  Status setupFunctions(uint64_t functions,
+                        const sp<IUsbGadgetCallback>& callback,
+                        uint64_t timeout);
+};
+
+}  // namespace implementation
+}  // namespace V1_0
+}  // namespace gadget
+}  // namespace usb
+}  // namespace hardware
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_USB_V1_2_USBGADGET_H
diff --git a/usb/android.hardware.usb@1.1-service.crosshatch.rc b/usb/android.hardware.usb@1.1-service.crosshatch.rc
index 8fa21ed..2ca62c0 100644
--- a/usb/android.hardware.usb@1.1-service.crosshatch.rc
+++ b/usb/android.hardware.usb@1.1-service.crosshatch.rc
@@ -1,7 +1,7 @@
 service vendor.usb-hal-1-1 /vendor/bin/hw/android.hardware.usb@1.1-service.crosshatch
     class hal
     user system
-    group system
+    group system shell mtp
 
 on boot
     chown root system /sys/class/typec/port0/power_role
diff --git a/usb/service.cpp b/usb/service.cpp
index 6d00728..372267e 100644
--- a/usb/service.cpp
+++ b/usb/service.cpp
@@ -18,6 +18,7 @@
 
 #include <hidl/HidlTransportSupport.h>
 #include "Usb.h"
+#include "UsbGadget.h"
 
 using android::sp;
 
@@ -27,15 +28,18 @@ using android::hardware::joinRpcThreadpool;
 
 // Generated HIDL files
 using android::hardware::usb::V1_1::IUsb;
+using android::hardware::usb::gadget::V1_0::IUsbGadget;
 using android::hardware::usb::V1_1::implementation::Usb;
+using android::hardware::usb::gadget::V1_0::implementation::UsbGadget;
 
-using android::status_t;
 using android::OK;
+using android::status_t;
 
 int main() {
     android::sp<IUsb> service = new Usb();
+    android::sp<IUsbGadget> service2 = new UsbGadget();
 
-    configureRpcThreadpool(1, true /*callerWillJoin*/);
+    configureRpcThreadpool(2, true /*callerWillJoin*/);
     status_t status = service->registerAsService();
 
     if (status != OK) {
@@ -43,6 +47,13 @@ int main() {
         return 1;
     }
 
+    status = service2->registerAsService();
+
+    if (status != OK) {
+        ALOGE("Cannot register USB Gadget HAL service");
+        return 1;
+    }
+
     ALOGI("USB HAL Ready.");
     joinRpcThreadpool();
     // Under noraml cases, execution will not reach this line.