aidl: usb: Import default implementation

* From hardware/interfaces @ android-13.0.0_r3

Change-Id: I4ac9478286577a7ea5150b007d7e34c26e22ca38

aidl/usb/Android.bp

@@ -0,0 +1,35 @@
+//
+// Copyright (C) 2021 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.
+//
+
+cc_binary {
+    name: "android.hardware.usb-service.example",
+    relative_install_path: "hw",
+    init_rc: ["android.hardware.usb-service.example.rc"],
+    vintf_fragments: ["android.hardware.usb-service.example.xml"],
+    vendor: true,
+    srcs: [
+        "service.cpp",
+        "Usb.cpp",
+    ],
+    shared_libs: [
+        "android.hardware.usb-V1-ndk",
+        "libbase",
+        "libbinder_ndk",
+	"libcutils",
+        "liblog",
+        "libutils",
+    ],
+}

aidl/usb/Usb.cpp

@@ -0,0 +1,743 @@
+/*
+ * Copyright (C) 2021 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.aidl-service"
+
+#include <aidl/android/hardware/usb/PortRole.h>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/strings.h>
+#include <assert.h>
+#include <dirent.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <chrono>
+#include <regex>
+#include <thread>
+#include <unordered_map>
+
+#include <cutils/uevent.h>
+#include <sys/epoll.h>
+#include <utils/Errors.h>
+#include <utils/StrongPointer.h>
+
+#include "Usb.h"
+
+using android::base::GetProperty;
+using android::base::Trim;
+
+namespace aidl {
+namespace android {
+namespace hardware {
+namespace usb {
+
+constexpr char kTypecPath[] = "/sys/class/typec/";
+constexpr char kDataRoleNode[] = "/data_role";
+constexpr char kPowerRoleNode[] = "/power_role";
+
+// Set by the signal handler to destroy the thread
+volatile bool destroyThread;
+
+void queryVersionHelper(android::hardware::usb::Usb *usb,
+                        std::vector<PortStatus> *currentPortStatus);
+
+ScopedAStatus Usb::enableUsbData(const string& in_portName, bool in_enable, int64_t in_transactionId) {
+    std::vector<PortStatus> currentPortStatus;
+
+    pthread_mutex_lock(&mLock);
+    if (mCallback != NULL) {
+        ScopedAStatus ret = mCallback->notifyEnableUsbDataStatus(
+            in_portName, true, in_enable ? Status::SUCCESS : Status::ERROR, in_transactionId);
+        if (!ret.isOk())
+            ALOGE("notifyEnableUsbDataStatus error %s", ret.getDescription().c_str());
+    } else {
+        ALOGE("Not notifying the userspace. Callback is not set");
+    }
+    pthread_mutex_unlock(&mLock);
+    queryVersionHelper(this, &currentPortStatus);
+
+    return ScopedAStatus::ok();
+}
+
+ScopedAStatus Usb::enableUsbDataWhileDocked(const string& in_portName, int64_t in_transactionId) {
+
+    pthread_mutex_lock(&mLock);
+    if (mCallback != NULL) {
+        ScopedAStatus ret = mCallback->notifyEnableUsbDataWhileDockedStatus(
+            in_portName, Status::NOT_SUPPORTED, in_transactionId);
+        if (!ret.isOk())
+            ALOGE("notifyEnableUsbDataWhileDockedStatus error %s", ret.getDescription().c_str());
+    } else {
+        ALOGE("Not notifying the userspace. Callback is not set");
+    }
+    pthread_mutex_unlock(&mLock);
+
+    return ScopedAStatus::ok();
+}
+
+ScopedAStatus Usb::resetUsbPort(const string& in_portName, int64_t in_transactionId) {
+
+    pthread_mutex_lock(&mLock);
+    if (mCallback != NULL) {
+        ScopedAStatus ret = mCallback->notifyResetUsbPortStatus(
+            in_portName, Status::NOT_SUPPORTED, in_transactionId);
+        if (!ret.isOk())
+            ALOGE("notifyResetUsbPortStatus error %s", ret.getDescription().c_str());
+    } else {
+        ALOGE("Not notifying the userspace. Callback is not set");
+    }
+    pthread_mutex_unlock(&mLock);
+
+    return ScopedAStatus::ok();
+}
+
+Status queryMoistureDetectionStatus(std::vector<PortStatus> *currentPortStatus) {
+    string enabled, status, path, DetectedPath;
+
+    for (int i = 0; i < currentPortStatus->size(); i++) {
+        (*currentPortStatus)[i].supportedContaminantProtectionModes
+                .push_back(ContaminantProtectionMode::NONE);
+        (*currentPortStatus)[i].contaminantProtectionStatus
+                = ContaminantProtectionStatus::NONE;
+        (*currentPortStatus)[i].contaminantDetectionStatus
+                = ContaminantDetectionStatus::NOT_SUPPORTED;
+        (*currentPortStatus)[i].supportsEnableContaminantPresenceDetection = false;
+        (*currentPortStatus)[i].supportsEnableContaminantPresenceProtection = false;
+    }
+
+    return Status::SUCCESS;
+}
+
+string appendRoleNodeHelper(const string &portName, PortRole::Tag tag) {
+    string node(kTypecPath + portName);
+
+    switch (tag) {
+        case PortRole::dataRole:
+            return node + kDataRoleNode;
+        case PortRole::powerRole:
+            return node + kPowerRoleNode;
+        case PortRole::mode:
+            return node + "/port_type";
+        default:
+            return "";
+    }
+}
+
+string convertRoletoString(PortRole role) {
+    if (role.getTag() == PortRole::powerRole) {
+        if (role.get<PortRole::powerRole>() == PortPowerRole::SOURCE)
+            return "source";
+        else if (role.get<PortRole::powerRole>() == PortPowerRole::SINK)
+            return "sink";
+    } else if (role.getTag() == PortRole::dataRole) {
+        if (role.get<PortRole::dataRole>() == PortDataRole::HOST)
+            return "host";
+        if (role.get<PortRole::dataRole>() == PortDataRole::DEVICE)
+            return "device";
+    } else if (role.getTag() == PortRole::mode) {
+        if (role.get<PortRole::mode>() == PortMode::UFP)
+            return "sink";
+        if (role.get<PortRole::mode>() == PortMode::DFP)
+            return "source";
+    }
+    return "none";
+}
+
+void extractRole(string *roleName) {
+    std::size_t first, last;
+
+    first = roleName->find("[");
+    last = roleName->find("]");
+
+    if (first != string::npos && last != string::npos) {
+        *roleName = roleName->substr(first + 1, last - first - 1);
+    }
+}
+
+void switchToDrp(const string &portName) {
+    string filename = appendRoleNodeHelper(string(portName.c_str()), PortRole::mode);
+    FILE *fp;
+
+    if (filename != "") {
+        fp = fopen(filename.c_str(), "w");
+        if (fp != NULL) {
+            int ret = fputs("dual", fp);
+            fclose(fp);
+            if (ret == EOF)
+                ALOGE("Fatal: Error while switching back to drp");
+        } else {
+            ALOGE("Fatal: Cannot open file to switch back to drp");
+        }
+    } else {
+        ALOGE("Fatal: invalid node type");
+    }
+}
+
+bool switchMode(const string &portName, const PortRole &in_role, struct Usb *usb) {
+    string filename = appendRoleNodeHelper(string(portName.c_str()), in_role.getTag());
+    string written;
+    FILE *fp;
+    bool roleSwitch = false;
+
+    if (filename == "") {
+        ALOGE("Fatal: invalid node type");
+        return false;
+    }
+
+    fp = fopen(filename.c_str(), "w");
+    if (fp != NULL) {
+        // Hold the lock here to prevent loosing connected signals
+        // as once the file is written the partner added signal
+        // can arrive anytime.
+        pthread_mutex_lock(&usb->mPartnerLock);
+        usb->mPartnerUp = false;
+        int ret = fputs(convertRoletoString(in_role).c_str(), fp);
+        fclose(fp);
+
+        if (ret != EOF) {
+            struct timespec to;
+            struct timespec now;
+
+        wait_again:
+            clock_gettime(CLOCK_MONOTONIC, &now);
+            to.tv_sec = now.tv_sec + PORT_TYPE_TIMEOUT;
+            to.tv_nsec = now.tv_nsec;
+
+            int err = pthread_cond_timedwait(&usb->mPartnerCV, &usb->mPartnerLock, &to);
+            // There are no uevent signals which implies role swap timed out.
+            if (err == ETIMEDOUT) {
+                ALOGI("uevents wait timedout");
+                // Validity check.
+            } else if (!usb->mPartnerUp) {
+                goto wait_again;
+                // Role switch succeeded since usb->mPartnerUp is true.
+            } else {
+                roleSwitch = true;
+            }
+        } else {
+            ALOGI("Role switch failed while wrting to file");
+        }
+        pthread_mutex_unlock(&usb->mPartnerLock);
+    }
+
+    if (!roleSwitch)
+        switchToDrp(string(portName.c_str()));
+
+    return roleSwitch;
+}
+
+Usb::Usb()
+    : mLock(PTHREAD_MUTEX_INITIALIZER),
+      mRoleSwitchLock(PTHREAD_MUTEX_INITIALIZER),
+      mPartnerLock(PTHREAD_MUTEX_INITIALIZER),
+      mPartnerUp(false)
+{
+    pthread_condattr_t attr;
+    if (pthread_condattr_init(&attr)) {
+        ALOGE("pthread_condattr_init failed: %s", strerror(errno));
+        abort();
+    }
+    if (pthread_condattr_setclock(&attr, CLOCK_MONOTONIC)) {
+        ALOGE("pthread_condattr_setclock failed: %s", strerror(errno));
+        abort();
+    }
+    if (pthread_cond_init(&mPartnerCV, &attr)) {
+        ALOGE("pthread_cond_init failed: %s", strerror(errno));
+        abort();
+    }
+    if (pthread_condattr_destroy(&attr)) {
+        ALOGE("pthread_condattr_destroy failed: %s", strerror(errno));
+        abort();
+    }
+}
+
+ScopedAStatus Usb::switchRole(const string& in_portName,
+        const PortRole& in_role, int64_t in_transactionId) {
+    string filename = appendRoleNodeHelper(string(in_portName.c_str()), in_role.getTag());
+    string written;
+    FILE *fp;
+    bool roleSwitch = false;
+
+    if (filename == "") {
+        ALOGE("Fatal: invalid node type");
+        return ScopedAStatus::ok();
+    }
+
+    pthread_mutex_lock(&mRoleSwitchLock);
+
+    ALOGI("filename write: %s role:%s", filename.c_str(), convertRoletoString(in_role).c_str());
+
+    if (in_role.getTag() == PortRole::mode) {
+        roleSwitch = switchMode(in_portName, in_role, this);
+    } else {
+        fp = fopen(filename.c_str(), "w");
+        if (fp != NULL) {
+            int ret = fputs(convertRoletoString(in_role).c_str(), fp);
+            fclose(fp);
+            if ((ret != EOF) && ReadFileToString(filename, &written)) {
+                written = Trim(written);
+                extractRole(&written);
+                ALOGI("written: %s", written.c_str());
+                if (written == convertRoletoString(in_role)) {
+                    roleSwitch = true;
+                } else {
+                    ALOGE("Role switch failed");
+                }
+            } else {
+                ALOGE("failed to update the new role");
+            }
+        } else {
+            ALOGE("fopen failed");
+        }
+    }
+
+    pthread_mutex_lock(&mLock);
+    if (mCallback != NULL) {
+         ScopedAStatus ret = mCallback->notifyRoleSwitchStatus(
+            in_portName, in_role, roleSwitch ? Status::SUCCESS : Status::ERROR, in_transactionId);
+        if (!ret.isOk())
+            ALOGE("RoleSwitchStatus error %s", ret.getDescription().c_str());
+    } else {
+        ALOGE("Not notifying the userspace. Callback is not set");
+    }
+    pthread_mutex_unlock(&mLock);
+    pthread_mutex_unlock(&mRoleSwitchLock);
+
+    return ScopedAStatus::ok();
+}
+
+ScopedAStatus Usb::limitPowerTransfer(const string& in_portName, bool /*in_limit*/,
+        int64_t in_transactionId) {
+    std::vector<PortStatus> currentPortStatus;
+
+    pthread_mutex_lock(&mLock);
+    if (mCallback != NULL && in_transactionId >= 0) {
+        ScopedAStatus ret = mCallback->notifyLimitPowerTransferStatus(
+                in_portName, false, Status::NOT_SUPPORTED, in_transactionId);
+        if (!ret.isOk())
+            ALOGE("limitPowerTransfer error %s", ret.getDescription().c_str());
+    } else {
+        ALOGE("Not notifying the userspace. Callback is not set");
+    }
+    pthread_mutex_unlock(&mLock);
+
+    return ScopedAStatus::ok();
+}
+
+Status getAccessoryConnected(const string &portName, string *accessory) {
+    string filename = kTypecPath + portName + "-partner/accessory_mode";
+
+    if (!ReadFileToString(filename, accessory)) {
+        ALOGE("getAccessoryConnected: Failed to open filesystem node: %s", filename.c_str());
+        return Status::ERROR;
+    }
+    *accessory = Trim(*accessory);
+
+    return Status::SUCCESS;
+}
+
+Status getCurrentRoleHelper(const string &portName, bool connected, PortRole *currentRole) {
+    string filename;
+    string roleName;
+    string accessory;
+
+    // Mode
+
+    if (currentRole->getTag() == PortRole::powerRole) {
+        filename = kTypecPath + portName + kPowerRoleNode;
+        currentRole->set<PortRole::powerRole>(PortPowerRole::NONE);
+    } else if (currentRole->getTag() == PortRole::dataRole) {
+        filename = kTypecPath + portName + kDataRoleNode;
+        currentRole->set<PortRole::dataRole>(PortDataRole::NONE);
+    } else if (currentRole->getTag() == PortRole::mode) {
+        filename = kTypecPath + portName + kDataRoleNode;
+        currentRole->set<PortRole::mode>(PortMode::NONE);
+    } else {
+        return Status::ERROR;
+    }
+
+    if (!connected)
+        return Status::SUCCESS;
+
+    if (currentRole->getTag() == PortRole::mode) {
+        if (getAccessoryConnected(portName, &accessory) != Status::SUCCESS) {
+            return Status::ERROR;
+        }
+        if (accessory == "analog_audio") {
+            currentRole->set<PortRole::mode>(PortMode::AUDIO_ACCESSORY);
+            return Status::SUCCESS;
+        } else if (accessory == "debug") {
+            currentRole->set<PortRole::mode>(PortMode::DEBUG_ACCESSORY);
+            return Status::SUCCESS;
+        }
+    }
+
+    if (!ReadFileToString(filename, &roleName)) {
+        ALOGE("getCurrentRole: Failed to open filesystem node: %s", filename.c_str());
+        return Status::ERROR;
+    }
+
+    roleName = Trim(roleName);
+    extractRole(&roleName);
+
+    if (roleName == "source") {
+        currentRole->set<PortRole::powerRole>(PortPowerRole::SOURCE);
+    } else if (roleName == "sink") {
+        currentRole->set<PortRole::powerRole>(PortPowerRole::SINK);
+    } else if (roleName == "host") {
+        if (currentRole->getTag() == PortRole::dataRole)
+            currentRole->set<PortRole::dataRole>(PortDataRole::HOST);
+        else
+            currentRole->set<PortRole::mode>(PortMode::DFP);
+    } else if (roleName == "device") {
+        if (currentRole->getTag() == PortRole::dataRole)
+            currentRole->set<PortRole::dataRole>(PortDataRole::DEVICE);
+        else
+            currentRole->set<PortRole::mode>(PortMode::UFP);
+    } else if (roleName != "none") {
+        /* case for none has already been addressed.
+         * so we check if the role isn't none.
+         */
+        return Status::UNRECOGNIZED_ROLE;
+    }
+
+    return Status::SUCCESS;
+}
+
+Status getTypeCPortNamesHelper(std::unordered_map<string, bool> *names) {
+    DIR *dp;
+
+    dp = opendir(kTypecPath);
+    if (dp != NULL) {
+        struct dirent *ep;
+
+        while ((ep = readdir(dp))) {
+            if (ep->d_type == DT_LNK) {
+                if (string::npos == string(ep->d_name).find("-partner")) {
+                    std::unordered_map<string, bool>::const_iterator portName =
+                        names->find(ep->d_name);
+                    if (portName == names->end()) {
+                        names->insert({ep->d_name, false});
+                    }
+                } else {
+                    (*names)[std::strtok(ep->d_name, "-")] = true;
+                }
+            }
+        }
+        closedir(dp);
+        return Status::SUCCESS;
+    }
+
+    ALOGE("Failed to open /sys/class/typec");
+    return Status::ERROR;
+}
+
+bool canSwitchRoleHelper(const string &portName) {
+    string filename = kTypecPath + portName + "-partner/supports_usb_power_delivery";
+    string supportsPD;
+
+    if (ReadFileToString(filename, &supportsPD)) {
+        supportsPD = Trim(supportsPD);
+        if (supportsPD == "yes") {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+Status getPortStatusHelper(std::vector<PortStatus> *currentPortStatus) {
+    std::unordered_map<string, bool> names;
+    Status result = getTypeCPortNamesHelper(&names);
+    int i = -1;
+
+    if (result == Status::SUCCESS) {
+        currentPortStatus->resize(names.size());
+        for (std::pair<string, bool> port : names) {
+            i++;
+            ALOGI("%s", port.first.c_str());
+            (*currentPortStatus)[i].portName = port.first;
+
+            PortRole currentRole;
+            currentRole.set<PortRole::powerRole>(PortPowerRole::NONE);
+            if (getCurrentRoleHelper(port.first, port.second, &currentRole) == Status::SUCCESS){
+                (*currentPortStatus)[i].currentPowerRole = currentRole.get<PortRole::powerRole>();
+            } else {
+                ALOGE("Error while retrieving portNames");
+                goto done;
+            }
+
+            currentRole.set<PortRole::dataRole>(PortDataRole::NONE);
+            if (getCurrentRoleHelper(port.first, port.second, &currentRole) == Status::SUCCESS) {
+                (*currentPortStatus)[i].currentDataRole = currentRole.get<PortRole::dataRole>();
+            } else {
+                ALOGE("Error while retrieving current port role");
+                goto done;
+            }
+
+            currentRole.set<PortRole::mode>(PortMode::NONE);
+            if (getCurrentRoleHelper(port.first, port.second, &currentRole) == Status::SUCCESS) {
+                (*currentPortStatus)[i].currentMode = currentRole.get<PortRole::mode>();
+            } else {
+                ALOGE("Error while retrieving current data role");
+                goto done;
+            }
+
+            (*currentPortStatus)[i].canChangeMode = true;
+            (*currentPortStatus)[i].canChangeDataRole =
+                port.second ? canSwitchRoleHelper(port.first) : false;
+            (*currentPortStatus)[i].canChangePowerRole =
+                port.second ? canSwitchRoleHelper(port.first) : false;
+
+            (*currentPortStatus)[i].supportedModes.push_back(PortMode::DRP);
+            (*currentPortStatus)[i].usbDataStatus.push_back(UsbDataStatus::ENABLED);
+
+            ALOGI("%d:%s connected:%d canChangeMode:%d canChagedata:%d canChangePower:%d "
+                "usbDataEnabled:%d",
+                i, port.first.c_str(), port.second,
+                (*currentPortStatus)[i].canChangeMode,
+                (*currentPortStatus)[i].canChangeDataRole,
+                (*currentPortStatus)[i].canChangePowerRole, 0);
+        }
+
+        return Status::SUCCESS;
+    }
+done:
+    return Status::ERROR;
+}
+
+void queryVersionHelper(android::hardware::usb::Usb *usb,
+                        std::vector<PortStatus> *currentPortStatus) {
+    Status status;
+    pthread_mutex_lock(&usb->mLock);
+    status = getPortStatusHelper(currentPortStatus);
+    queryMoistureDetectionStatus(currentPortStatus);
+    if (usb->mCallback != NULL) {
+        ScopedAStatus ret = usb->mCallback->notifyPortStatusChange(*currentPortStatus,
+            status);
+        if (!ret.isOk())
+            ALOGE("queryPortStatus error %s", ret.getDescription().c_str());
+    } else {
+        ALOGI("Notifying userspace skipped. Callback is NULL");
+    }
+    pthread_mutex_unlock(&usb->mLock);
+}
+
+ScopedAStatus Usb::queryPortStatus(int64_t in_transactionId) {
+    std::vector<PortStatus> currentPortStatus;
+
+    queryVersionHelper(this, &currentPortStatus);
+    pthread_mutex_lock(&mLock);
+    if (mCallback != NULL) {
+        ScopedAStatus ret = mCallback->notifyQueryPortStatus(
+            "all", Status::SUCCESS, in_transactionId);
+        if (!ret.isOk())
+            ALOGE("notifyQueryPortStatus error %s", ret.getDescription().c_str());
+    } else {
+        ALOGE("Not notifying the userspace. Callback is not set");
+    }
+    pthread_mutex_unlock(&mLock);
+
+    return ScopedAStatus::ok();
+}
+
+ScopedAStatus Usb::enableContaminantPresenceDetection(const string& in_portName,
+        bool /*in_enable*/, int64_t in_transactionId) {
+    std::vector<PortStatus> currentPortStatus;
+
+    pthread_mutex_lock(&mLock);
+    if (mCallback != NULL) {
+        ScopedAStatus ret = mCallback->notifyContaminantEnabledStatus(
+            in_portName, false, Status::ERROR, in_transactionId);
+        if (!ret.isOk())
+            ALOGE("enableContaminantPresenceDetection  error %s", ret.getDescription().c_str());
+    } else {
+        ALOGE("Not notifying the userspace. Callback is not set");
+    }
+    pthread_mutex_unlock(&mLock);
+
+    queryVersionHelper(this, &currentPortStatus);
+    return ScopedAStatus::ok();
+}
+
+
+struct data {
+    int uevent_fd;
+    ::aidl::android::hardware::usb::Usb *usb;
+};
+
+static void uevent_event(uint32_t /*epevents*/, struct data *payload) {
+    char msg[UEVENT_MSG_LEN + 2];
+    char *cp;
+    int n;
+
+    n = uevent_kernel_multicast_recv(payload->uevent_fd, msg, UEVENT_MSG_LEN);
+    if (n <= 0)
+        return;
+    if (n >= UEVENT_MSG_LEN) /* overflow -- discard */
+        return;
+
+    msg[n] = '\0';
+    msg[n + 1] = '\0';
+    cp = msg;
+
+    while (*cp) {
+        if (std::regex_match(cp, std::regex("(add)(.*)(-partner)"))) {
+            ALOGI("partner added");
+            pthread_mutex_lock(&payload->usb->mPartnerLock);
+            payload->usb->mPartnerUp = true;
+            pthread_cond_signal(&payload->usb->mPartnerCV);
+            pthread_mutex_unlock(&payload->usb->mPartnerLock);
+        } else if (!strncmp(cp, "DEVTYPE=typec_", strlen("DEVTYPE=typec_"))) {
+            std::vector<PortStatus> currentPortStatus;
+            queryVersionHelper(payload->usb, &currentPortStatus);
+
+            // Role switch is not in progress and port is in disconnected state
+            if (!pthread_mutex_trylock(&payload->usb->mRoleSwitchLock)) {
+                for (unsigned long i = 0; i < currentPortStatus.size(); i++) {
+                    DIR *dp =
+                        opendir(string(kTypecPath +
+                                       string(currentPortStatus[i].portName.c_str()) +
+                                       "-partner").c_str());
+                    if (dp == NULL) {
+                        switchToDrp(currentPortStatus[i].portName);
+                    } else {
+                        closedir(dp);
+                    }
+                }
+                pthread_mutex_unlock(&payload->usb->mRoleSwitchLock);
+            }
+            break;
+        } /* advance to after the next \0 */
+        while (*cp++) {
+        }
+    }
+}
+
+void *work(void *param) {
+    int epoll_fd, uevent_fd;
+    struct epoll_event ev;
+    int nevents = 0;
+    struct data payload;
+
+    uevent_fd = uevent_open_socket(UEVENT_MAX_EVENTS * UEVENT_MSG_LEN, true);
+
+    if (uevent_fd < 0) {
+        ALOGE("uevent_init: uevent_open_socket failed\n");
+        return NULL;
+    }
+
+    payload.uevent_fd = uevent_fd;
+    payload.usb = (::aidl::android::hardware::usb::Usb *)param;
+
+    fcntl(uevent_fd, F_SETFL, O_NONBLOCK);
+
+    ev.events = EPOLLIN;
+    ev.data.ptr = (void *)uevent_event;
+
+    epoll_fd = epoll_create(UEVENT_MAX_EVENTS);
+    if (epoll_fd == -1) {
+        ALOGE("epoll_create failed; errno=%d", errno);
+        goto error;
+    }
+
+    if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, uevent_fd, &ev) == -1) {
+        ALOGE("epoll_ctl failed; errno=%d", errno);
+        goto error;
+    }
+
+    while (!destroyThread) {
+        struct epoll_event events[UEVENT_MAX_EVENTS];
+
+        nevents = epoll_wait(epoll_fd, events, UEVENT_MAX_EVENTS, -1);
+        if (nevents == -1) {
+            if (errno == EINTR)
+                continue;
+            ALOGE("usb epoll_wait failed; errno=%d", errno);
+            break;
+        }
+
+        for (int n = 0; n < nevents; ++n) {
+            if (events[n].data.ptr)
+                (*(void (*)(int, struct data *payload))events[n].data.ptr)(events[n].events,
+                                                                           &payload);
+        }
+    }
+
+    ALOGI("exiting worker thread");
+error:
+    close(uevent_fd);
+
+    if (epoll_fd >= 0)
+        close(epoll_fd);
+
+    return NULL;
+}
+
+void sighandler(int sig) {
+    if (sig == SIGUSR1) {
+        destroyThread = true;
+        ALOGI("destroy set");
+        return;
+    }
+    signal(SIGUSR1, sighandler);
+}
+
+ScopedAStatus Usb::setCallback(
+        const shared_ptr<IUsbCallback>& in_callback) {
+
+    pthread_mutex_lock(&mLock);
+    if ((mCallback == NULL && in_callback == NULL) ||
+            (mCallback != NULL && in_callback != NULL)) {
+        mCallback = in_callback;
+        pthread_mutex_unlock(&mLock);
+        return ScopedAStatus::ok();
+    }
+
+    mCallback = in_callback;
+    ALOGI("registering callback");
+
+    if (mCallback == NULL) {
+        if  (!pthread_kill(mPoll, SIGUSR1)) {
+            pthread_join(mPoll, NULL);
+            ALOGI("pthread destroyed");
+        }
+        pthread_mutex_unlock(&mLock);
+        return ScopedAStatus::ok();
+    }
+
+    destroyThread = false;
+    signal(SIGUSR1, sighandler);
+
+    /*
+     * Create a background thread if the old callback value is NULL
+     * and being updated with a new value.
+     */
+    if (pthread_create(&mPoll, NULL, work, this)) {
+        ALOGE("pthread creation failed %d", errno);
+        mCallback = NULL;
+    }
+
+    pthread_mutex_unlock(&mLock);
+    return ScopedAStatus::ok();
+}
+
+} // namespace usb
+} // namespace hardware
+} // namespace android
+} // aidl

aidl/usb/Usb.h

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#pragma once
+
+#include <android-base/file.h>
+#include <aidl/android/hardware/usb/BnUsb.h>
+#include <aidl/android/hardware/usb/BnUsbCallback.h>
+#include <utils/Log.h>
+
+#define UEVENT_MSG_LEN     2048
+#define UEVENT_MAX_EVENTS  64
+// The type-c stack waits for 4.5 - 5.5 secs before declaring a port non-pd.
+// The -partner directory would not be created until this is done.
+// Having a margin of ~3 secs for the directory and other related bookeeping
+// structures created and uvent fired.
+#define PORT_TYPE_TIMEOUT 8
+
+namespace aidl {
+namespace android {
+namespace hardware {
+namespace usb {
+
+using ::aidl::android::hardware::usb::IUsbCallback;
+using ::aidl::android::hardware::usb::PortRole;
+using ::android::base::ReadFileToString;
+using ::android::base::WriteStringToFile;
+using ::android::sp;
+using ::ndk::ScopedAStatus;
+using ::std::shared_ptr;
+using ::std::string;
+
+struct Usb : public BnUsb {
+    Usb();
+
+    ScopedAStatus enableContaminantPresenceDetection(const std::string& in_portName,
+            bool in_enable, int64_t in_transactionId) override;
+    ScopedAStatus queryPortStatus(int64_t in_transactionId) override;
+    ScopedAStatus setCallback(const shared_ptr<IUsbCallback>& in_callback) override;
+    ScopedAStatus switchRole(const string& in_portName, const PortRole& in_role,
+            int64_t in_transactionId) override;
+    ScopedAStatus enableUsbData(const string& in_portName, bool in_enable,
+            int64_t in_transactionId) override;
+    ScopedAStatus enableUsbDataWhileDocked(const string& in_portName,
+            int64_t in_transactionId) override;
+    ScopedAStatus limitPowerTransfer(const std::string& in_portName, bool in_limit,
+            int64_t in_transactionId)override;
+    ScopedAStatus resetUsbPort(const std::string& in_portName,
+            int64_t in_transactionId)override;
+
+    shared_ptr<IUsbCallback> mCallback;
+    // Protects mCallback variable
+    pthread_mutex_t mLock;
+    // Protects roleSwitch operation
+    pthread_mutex_t mRoleSwitchLock;
+    // Threads waiting for the partner to come back wait here
+    pthread_cond_t mPartnerCV;
+    // lock protecting mPartnerCV
+    pthread_mutex_t mPartnerLock;
+    // Variable to signal partner coming back online after type switch
+    bool mPartnerUp;
+  private:
+    pthread_t mPoll;
+};
+
+} // namespace usb
+} // namespace hardware
+} // namespace android
+} // aidl

aidl/usb/android.hardware.usb-service.example.rc

@@ -0,0 +1,4 @@
+service vendor.usb_default /vendor/bin/hw/android.hardware.usb-service.example
+    class hal
+    user system
+    group system

aidl/usb/android.hardware.usb-service.example.xml

@@ -0,0 +1,10 @@
+<manifest version="1.0" type="device">
+    <hal format="aidl">
+        <name>android.hardware.usb</name>
+        <version>1</version>
+        <interface>
+            <name>IUsb</name>
+            <instance>default</instance>
+        </interface>
+    </hal>
+</manifest>

aidl/usb/service.cpp

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#include <android-base/logging.h>
+#include <android/binder_manager.h>
+#include <android/binder_process.h>
+
+#include "Usb.h"
+
+using ::aidl::android::hardware::usb::Usb;
+
+int main() {
+    ABinderProcess_setThreadPoolMaxThreadCount(0);
+    std::shared_ptr<Usb> usb = ndk::SharedRefBase::make<Usb>();
+
+    const std::string instance = std::string() + Usb::descriptor + "/default";
+    binder_status_t status = AServiceManager_addService(usb->asBinder().get(), instance.c_str());
+    CHECK(status == STATUS_OK);
+
+    ABinderProcess_joinThreadPool();
+    return -1; // Should never be reached
+}