usb: add gadget lib

* Copy from hardware/interfaces/usb/gadget/1.2/default.

usb/lib/include/UsbGadgetCommon.h

@@ -0,0 +1,179 @@
+/*
+ * Copyright (C) 2020 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 HARDWARE_USB_USBGADGETCOMMON_H
+#define HARDWARE_USB_USBGADGETCOMMON_H
+
+#include <android-base/file.h>
+#include <android-base/properties.h>
+#include <android-base/unique_fd.h>
+
+#include <android/hardware/usb/gadget/1.2/IUsbGadget.h>
+#include <android/hardware/usb/gadget/1.2/types.h>
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/epoll.h>
+#include <sys/eventfd.h>
+#include <sys/inotify.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <utils/Log.h>
+#include <chrono>
+#include <condition_variable>
+#include <mutex>
+#include <string>
+#include <thread>
+
+namespace android {
+namespace hardware {
+namespace usb {
+namespace gadget {
+
+constexpr int kBufferSize = 512;
+constexpr int kMaxFilePathLength = 256;
+constexpr int kEpollEvents = 10;
+constexpr bool kDebug = false;
+constexpr int kDisconnectWaitUs = 100000;
+constexpr int kPullUpDelay = 500000;
+constexpr int kShutdownMonitor = 100;
+
+constexpr char kBuildType[] = "ro.build.type";
+constexpr char kPersistentVendorConfig[] = "persist.vendor.usb.usbradio.config";
+constexpr char kVendorConfig[] = "vendor.usb.config";
+constexpr char kVendorRndisConfig[] = "vendor.usb.rndis.config";
+
+#define GADGET_PATH "/config/usb_gadget/g1/"
+#define PULLUP_PATH GADGET_PATH "UDC"
+#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"
+
+using ::android::base::GetProperty;
+using ::android::base::SetProperty;
+using ::android::base::unique_fd;
+using ::android::base::WriteStringToFile;
+using ::android::hardware::usb::gadget::V1_0::Status;
+using ::android::hardware::usb::gadget::V1_2::GadgetFunction;
+
+using ::std::lock_guard;
+using ::std::move;
+using ::std::mutex;
+using ::std::string;
+using ::std::thread;
+using ::std::unique_ptr;
+using ::std::vector;
+using ::std::chrono::microseconds;
+using ::std::chrono::steady_clock;
+using ::std::literals::chrono_literals::operator""ms;
+
+// MonitorFfs automously manages gadget pullup by monitoring
+// the ep file status. Restarts the usb gadget when the ep
+// owner restarts.
+class MonitorFfs {
+  private:
+    // Monitors the endpoints Inotify events.
+    unique_fd mInotifyFd;
+    // Control pipe for shutting down the mMonitor thread.
+    // mMonitor exits when SHUTDOWN_MONITOR is written into
+    // mEventFd/
+    unique_fd mEventFd;
+    // Pools on mInotifyFd and mEventFd.
+    unique_fd mEpollFd;
+    vector<int> mWatchFd;
+
+    // Maintains the list of Endpoints.
+    vector<string> mEndpointList;
+    // protects the CV.
+    std::mutex mLock;
+    std::condition_variable mCv;
+    // protects mInotifyFd, mEpollFd.
+    std::mutex mLockFd;
+
+    // Flag to maintain the current status of gadget pullup.
+    bool mCurrentUsbFunctionsApplied;
+
+    // Thread object that executes the ep monitoring logic.
+    unique_ptr<thread> mMonitor;
+    // Callback to be invoked when gadget is pulled up.
+    void (*mCallback)(bool functionsApplied, void* payload);
+    void* mPayload;
+    // Name of the USB gadget. Used for pullup.
+    const char* const mGadgetName;
+    // Monitor State
+    bool mMonitorRunning;
+
+  public:
+    MonitorFfs(const char* const gadget);
+    // Inits all the UniqueFds.
+    void reset();
+    // Starts monitoring endpoints and pullup the gadget when
+    // the descriptors are written.
+    bool startMonitor();
+    // Waits for timeout_ms for gadget pull up to happen.
+    // Returns immediately if the gadget is already pulled up.
+    bool waitForPullUp(int timeout_ms);
+    // Adds the given fd to the watch list.
+    bool addInotifyFd(string fd);
+    // Adds the given endpoint to the watch list.
+    void addEndPoint(string ep);
+    // Registers the async callback from the caller to notify the caller
+    // when the gadget pull up happens.
+    void registerFunctionsAppliedCallback(void (*callback)(bool functionsApplied, void*(payload)),
+                                          void* payload);
+    bool isMonitorRunning();
+    // Ep monitoring and the gadget pull up logic.
+    static void* startMonitorFd(void* param);
+};
+
+//**************** Helper functions ************************//
+
+// Adds the given fd to the epollfd(epfd).
+int addEpollFd(const unique_fd& epfd, const unique_fd& fd);
+// Removes all the usb functions link in the specified path.
+int unlinkFunctions(const char* path);
+// Craetes a configfs link for the function.
+int linkFunction(const char* function, int index);
+// Sets the USB VID and PID.
+Status setVidPid(const char* vid, const char* pid);
+// Extracts vendor functions from the vendor init properties.
+std::string getVendorFunctions();
+// Adds Adb to the usb configuration.
+Status addAdb(MonitorFfs* monitorFfs, int* functionCount);
+// Adds all applicable generic android usb functions other than ADB.
+Status addGenericAndroidFunctions(MonitorFfs* monitorFfs, uint64_t functions, bool* ffsEnabled,
+                                  int* functionCount);
+// Pulls down USB gadget.
+Status resetGadget();
+
+}  // namespace gadget
+}  // namespace usb
+}  // namespace hardware
+}  // namespace android
+#endif