diff --git a/audio/aidl/default/Android.bp b/audio/aidl/default/Android.bp
new file mode 100644
index 0000000..0a6fe60
--- /dev/null
+++ b/audio/aidl/default/Android.bp
@@ -0,0 +1,45 @@
+package {
+    // See: http://go/android-license-faq
+    // A large-scale-change added 'default_applicable_licenses' to import
+    // all of the 'license_kinds' from "hardware_interfaces_license"
+    // to get the below license kinds:
+    //   SPDX-license-identifier-Apache-2.0
+    default_applicable_licenses: ["hardware_interfaces_license"],
+}
+
+cc_library_static {
+    name: "libaudioserviceexampleimpl",
+    vendor: true,
+    shared_libs: [
+        "libbase",
+        "libbinder_ndk",
+        "android.hardware.audio.core-V1-ndk",
+    ],
+    export_include_dirs: ["include"],
+    srcs: [
+        "Config.cpp",
+        "Configuration.cpp",
+        "Module.cpp",
+        "Stream.cpp",
+    ],
+    visibility: [
+        ":__subpackages__",
+    ],
+}
+
+cc_binary {
+    name: "android.hardware.audio.service-aidl.example",
+    relative_install_path: "hw",
+    init_rc: ["android.hardware.audio.service-aidl.example.rc"],
+    vintf_fragments: ["android.hardware.audio.service-aidl.xml"],
+    vendor: true,
+    shared_libs: [
+        "libbase",
+        "libbinder_ndk",
+        "android.hardware.audio.core-V1-ndk",
+    ],
+    static_libs: [
+        "libaudioserviceexampleimpl",
+    ],
+    srcs: ["main.cpp"],
+}
diff --git a/audio/aidl/default/Config.cpp b/audio/aidl/default/Config.cpp
new file mode 100644
index 0000000..3f7a3d3
--- /dev/null
+++ b/audio/aidl/default/Config.cpp
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2022 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 "core-impl/Config.h"
+
+namespace aidl::android::hardware::audio::core {}  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/Configuration.cpp b/audio/aidl/default/Configuration.cpp
new file mode 100644
index 0000000..1104caa
--- /dev/null
+++ b/audio/aidl/default/Configuration.cpp
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2022 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 <aidl/android/media/audio/common/AudioChannelLayout.h>
+#include <aidl/android/media/audio/common/AudioDeviceType.h>
+#include <aidl/android/media/audio/common/AudioFormatType.h>
+#include <aidl/android/media/audio/common/AudioIoFlags.h>
+#include <aidl/android/media/audio/common/AudioOutputFlags.h>
+
+#include "aidl/android/media/audio/common/AudioFormatDescription.h"
+#include "core-impl/Configuration.h"
+
+using aidl::android::media::audio::common::AudioChannelLayout;
+using aidl::android::media::audio::common::AudioDeviceType;
+using aidl::android::media::audio::common::AudioFormatDescription;
+using aidl::android::media::audio::common::AudioFormatType;
+using aidl::android::media::audio::common::AudioGainConfig;
+using aidl::android::media::audio::common::AudioIoFlags;
+using aidl::android::media::audio::common::AudioOutputFlags;
+using aidl::android::media::audio::common::AudioPort;
+using aidl::android::media::audio::common::AudioPortConfig;
+using aidl::android::media::audio::common::AudioPortDeviceExt;
+using aidl::android::media::audio::common::AudioPortExt;
+using aidl::android::media::audio::common::AudioPortMixExt;
+using aidl::android::media::audio::common::AudioProfile;
+using aidl::android::media::audio::common::Int;
+using aidl::android::media::audio::common::PcmType;
+
+namespace aidl::android::hardware::audio::core::internal {
+
+static AudioProfile createProfile(PcmType pcmType, const std::vector<int32_t>& channelLayouts,
+                                  const std::vector<int32_t>& sampleRates) {
+    AudioProfile profile;
+    profile.format.type = AudioFormatType::PCM;
+    profile.format.pcm = pcmType;
+    for (auto layout : channelLayouts) {
+        profile.channelMasks.push_back(
+                AudioChannelLayout::make<AudioChannelLayout::layoutMask>(layout));
+    }
+    profile.sampleRates.insert(profile.sampleRates.end(), sampleRates.begin(), sampleRates.end());
+    return profile;
+}
+
+static AudioPortExt createDeviceExt(AudioDeviceType devType, int32_t flags) {
+    AudioPortDeviceExt deviceExt;
+    deviceExt.device.type.type = devType;
+    deviceExt.flags = flags;
+    return AudioPortExt::make<AudioPortExt::Tag::device>(deviceExt);
+}
+
+static AudioPortExt createPortMixExt(int32_t maxOpenStreamCount, int32_t maxActiveStreamCount) {
+    AudioPortMixExt mixExt;
+    mixExt.maxOpenStreamCount = maxOpenStreamCount;
+    mixExt.maxActiveStreamCount = maxActiveStreamCount;
+    return AudioPortExt::make<AudioPortExt::Tag::mix>(mixExt);
+}
+
+static AudioPort createPort(int32_t id, const std::string& name, int32_t flags, bool isInput,
+                            const AudioPortExt& ext) {
+    AudioPort port;
+    port.id = id;
+    port.name = name;
+    port.flags = isInput ? AudioIoFlags::make<AudioIoFlags::Tag::input>(flags)
+                         : AudioIoFlags::make<AudioIoFlags::Tag::output>(flags);
+    port.ext = ext;
+    return port;
+}
+
+static AudioPortConfig createPortConfig(int32_t id, int32_t portId, PcmType pcmType, int32_t layout,
+                                        int32_t sampleRate, int32_t flags, bool isInput,
+                                        const AudioPortExt& ext) {
+    AudioPortConfig config;
+    config.id = id;
+    config.portId = portId;
+    config.sampleRate = Int{.value = sampleRate};
+    config.channelMask = AudioChannelLayout::make<AudioChannelLayout::layoutMask>(layout);
+    config.format = AudioFormatDescription{.type = AudioFormatType::PCM, .pcm = pcmType};
+    config.gain = AudioGainConfig();
+    config.flags = isInput ? AudioIoFlags::make<AudioIoFlags::Tag::input>(flags)
+                           : AudioIoFlags::make<AudioIoFlags::Tag::output>(flags);
+    config.ext = ext;
+    return config;
+}
+
+static AudioRoute createRoute(const std::vector<int32_t>& sources, int32_t sink) {
+    AudioRoute route;
+    route.sinkPortId = sink;
+    route.sourcePortIds.insert(route.sourcePortIds.end(), sources.begin(), sources.end());
+    return route;
+}
+
+Configuration& getNullPrimaryConfiguration() {
+    static Configuration configuration = []() {
+        Configuration c;
+
+        AudioPort nullOutDevice =
+                createPort(c.nextPortId++, "Null", 0, false,
+                           createDeviceExt(AudioDeviceType::OUT_SPEAKER,
+                                           1 << AudioPortDeviceExt::FLAG_INDEX_DEFAULT_DEVICE));
+        c.ports.push_back(nullOutDevice);
+
+        AudioPort primaryOutMix = createPort(c.nextPortId++, "primary output",
+                                             1 << static_cast<int32_t>(AudioOutputFlags::PRIMARY),
+                                             false, createPortMixExt(1, 1));
+        primaryOutMix.profiles.push_back(
+                createProfile(PcmType::INT_16_BIT,
+                              {AudioChannelLayout::LAYOUT_MONO, AudioChannelLayout::LAYOUT_STEREO},
+                              {44100, 48000}));
+        primaryOutMix.profiles.push_back(
+                createProfile(PcmType::INT_24_BIT,
+                              {AudioChannelLayout::LAYOUT_MONO, AudioChannelLayout::LAYOUT_STEREO},
+                              {44100, 48000}));
+        c.ports.push_back(primaryOutMix);
+
+        c.routes.push_back(createRoute({primaryOutMix.id}, nullOutDevice.id));
+
+        c.initialConfigs.push_back(
+                createPortConfig(nullOutDevice.id, nullOutDevice.id, PcmType::INT_24_BIT,
+                                 AudioChannelLayout::LAYOUT_STEREO, 48000, 0, false,
+                                 createDeviceExt(AudioDeviceType::OUT_SPEAKER, 0)));
+
+        AudioPort loopOutDevice = createPort(c.nextPortId++, "Loopback Out", 0, false,
+                                             createDeviceExt(AudioDeviceType::OUT_SUBMIX, 0));
+        loopOutDevice.profiles.push_back(
+                createProfile(PcmType::INT_24_BIT, {AudioChannelLayout::LAYOUT_STEREO}, {48000}));
+        c.ports.push_back(loopOutDevice);
+
+        AudioPort loopOutMix =
+                createPort(c.nextPortId++, "loopback output", 0, false, createPortMixExt(0, 0));
+        loopOutMix.profiles.push_back(
+                createProfile(PcmType::INT_24_BIT, {AudioChannelLayout::LAYOUT_STEREO}, {48000}));
+        c.ports.push_back(loopOutMix);
+
+        c.routes.push_back(createRoute({loopOutMix.id}, loopOutDevice.id));
+
+        AudioPort zeroInDevice =
+                createPort(c.nextPortId++, "Zero", 0, true,
+                           createDeviceExt(AudioDeviceType::IN_MICROPHONE,
+                                           1 << AudioPortDeviceExt::FLAG_INDEX_DEFAULT_DEVICE));
+        c.ports.push_back(zeroInDevice);
+
+        AudioPort primaryInMix =
+                createPort(c.nextPortId++, "primary input", 0, true, createPortMixExt(2, 2));
+        primaryInMix.profiles.push_back(
+                createProfile(PcmType::INT_16_BIT,
+                              {AudioChannelLayout::LAYOUT_MONO, AudioChannelLayout::LAYOUT_STEREO,
+                               AudioChannelLayout::LAYOUT_FRONT_BACK},
+                              {8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000}));
+        primaryInMix.profiles.push_back(
+                createProfile(PcmType::INT_24_BIT,
+                              {AudioChannelLayout::LAYOUT_MONO, AudioChannelLayout::LAYOUT_STEREO,
+                               AudioChannelLayout::LAYOUT_FRONT_BACK},
+                              {8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000}));
+        c.ports.push_back(primaryInMix);
+
+        c.routes.push_back(createRoute({zeroInDevice.id}, primaryInMix.id));
+
+        c.initialConfigs.push_back(
+                createPortConfig(zeroInDevice.id, zeroInDevice.id, PcmType::INT_24_BIT,
+                                 AudioChannelLayout::LAYOUT_MONO, 48000, 0, true,
+                                 createDeviceExt(AudioDeviceType::IN_MICROPHONE, 0)));
+
+        AudioPort loopInDevice = createPort(c.nextPortId++, "Loopback In", 0, true,
+                                            createDeviceExt(AudioDeviceType::IN_SUBMIX, 0));
+        loopInDevice.profiles.push_back(
+                createProfile(PcmType::INT_24_BIT, {AudioChannelLayout::LAYOUT_STEREO}, {48000}));
+        c.ports.push_back(loopInDevice);
+
+        AudioPort loopInMix =
+                createPort(c.nextPortId++, "loopback input", 0, true, createPortMixExt(0, 0));
+        loopInMix.profiles.push_back(
+                createProfile(PcmType::INT_24_BIT, {AudioChannelLayout::LAYOUT_STEREO}, {48000}));
+        c.ports.push_back(loopInMix);
+
+        c.routes.push_back(createRoute({loopInDevice.id}, loopInMix.id));
+
+        c.portConfigs.insert(c.portConfigs.end(), c.initialConfigs.begin(), c.initialConfigs.end());
+        return c;
+    }();
+    return configuration;
+}
+
+}  // namespace aidl::android::hardware::audio::core::internal
diff --git a/audio/aidl/default/Module.cpp b/audio/aidl/default/Module.cpp
new file mode 100644
index 0000000..e0a68a5
--- /dev/null
+++ b/audio/aidl/default/Module.cpp
@@ -0,0 +1,522 @@
+/*
+ * Copyright (C) 2022 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 <algorithm>
+#include <set>
+
+#define LOG_TAG "AHAL_Module"
+#define LOG_NDEBUG 0
+#include <android-base/logging.h>
+
+#include <aidl/android/media/audio/common/AudioOutputFlags.h>
+
+#include "core-impl/Module.h"
+#include "core-impl/utils.h"
+
+using aidl::android::hardware::audio::common::SinkMetadata;
+using aidl::android::hardware::audio::common::SourceMetadata;
+using aidl::android::media::audio::common::AudioFormatDescription;
+using aidl::android::media::audio::common::AudioIoFlags;
+using aidl::android::media::audio::common::AudioOffloadInfo;
+using aidl::android::media::audio::common::AudioOutputFlags;
+using aidl::android::media::audio::common::AudioPort;
+using aidl::android::media::audio::common::AudioPortConfig;
+using aidl::android::media::audio::common::AudioPortExt;
+using aidl::android::media::audio::common::AudioProfile;
+using aidl::android::media::audio::common::Int;
+
+namespace aidl::android::hardware::audio::core {
+
+namespace {
+
+bool generateDefaultPortConfig(const AudioPort& port, AudioPortConfig* config) {
+    *config = {};
+    config->portId = port.id;
+    if (port.profiles.empty()) {
+        LOG(ERROR) << __func__ << ": port " << port.id << " has no profiles";
+        return false;
+    }
+    const auto& profile = port.profiles.begin();
+    config->format = profile->format;
+    if (profile->channelMasks.empty()) {
+        LOG(ERROR) << __func__ << ": the first profile in port " << port.id
+                   << " has no channel masks";
+        return false;
+    }
+    config->channelMask = *profile->channelMasks.begin();
+    if (profile->sampleRates.empty()) {
+        LOG(ERROR) << __func__ << ": the first profile in port " << port.id
+                   << " has no sample rates";
+        return false;
+    }
+    Int sampleRate;
+    sampleRate.value = *profile->sampleRates.begin();
+    config->sampleRate = sampleRate;
+    config->flags = port.flags;
+    config->ext = port.ext;
+    return true;
+}
+
+bool findAudioProfile(const AudioPort& port, const AudioFormatDescription& format,
+                      AudioProfile* profile) {
+    if (auto profilesIt =
+                find_if(port.profiles.begin(), port.profiles.end(),
+                        [&format](const auto& profile) { return profile.format == format; });
+        profilesIt != port.profiles.end()) {
+        *profile = *profilesIt;
+        return true;
+    }
+    return false;
+}
+}  // namespace
+
+void Module::cleanUpPatch(int32_t patchId) {
+    erase_all_values(mPatches, std::set<int32_t>{patchId});
+}
+
+void Module::cleanUpPatches(int32_t portConfigId) {
+    auto& patches = getConfig().patches;
+    if (patches.size() == 0) return;
+    auto range = mPatches.equal_range(portConfigId);
+    for (auto it = range.first; it != range.second; ++it) {
+        auto patchIt = findById<AudioPatch>(patches, it->second);
+        if (patchIt != patches.end()) {
+            erase_if(patchIt->sourcePortConfigIds,
+                     [portConfigId](auto e) { return e == portConfigId; });
+            erase_if(patchIt->sinkPortConfigIds,
+                     [portConfigId](auto e) { return e == portConfigId; });
+        }
+    }
+    std::set<int32_t> erasedPatches;
+    for (size_t i = patches.size() - 1; i != 0; --i) {
+        const auto& patch = patches[i];
+        if (patch.sourcePortConfigIds.empty() || patch.sinkPortConfigIds.empty()) {
+            erasedPatches.insert(patch.id);
+            patches.erase(patches.begin() + i);
+        }
+    }
+    erase_all_values(mPatches, erasedPatches);
+}
+
+internal::Configuration& Module::getConfig() {
+    if (!mConfig) {
+        mConfig.reset(new internal::Configuration(internal::getNullPrimaryConfiguration()));
+    }
+    return *mConfig;
+}
+
+void Module::registerPatch(const AudioPatch& patch) {
+    auto& configs = getConfig().portConfigs;
+    auto do_insert = [&](const std::vector<int32_t>& portConfigIds) {
+        for (auto portConfigId : portConfigIds) {
+            auto configIt = findById<AudioPortConfig>(configs, portConfigId);
+            if (configIt != configs.end()) {
+                mPatches.insert(std::pair{portConfigId, patch.id});
+                if (configIt->portId != portConfigId) {
+                    mPatches.insert(std::pair{configIt->portId, patch.id});
+                }
+            }
+        };
+    };
+    do_insert(patch.sourcePortConfigIds);
+    do_insert(patch.sinkPortConfigIds);
+}
+
+ndk::ScopedAStatus Module::getAudioPatches(std::vector<AudioPatch>* _aidl_return) {
+    *_aidl_return = getConfig().patches;
+    LOG(DEBUG) << __func__ << ": returning " << _aidl_return->size() << " patches";
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus Module::getAudioPort(int32_t in_portId, AudioPort* _aidl_return) {
+    auto& ports = getConfig().ports;
+    auto portIt = findById<AudioPort>(ports, in_portId);
+    if (portIt != ports.end()) {
+        *_aidl_return = *portIt;
+        LOG(DEBUG) << __func__ << ": returning port by id " << in_portId;
+        return ndk::ScopedAStatus::ok();
+    }
+    LOG(ERROR) << __func__ << ": port id " << in_portId << " not found";
+    return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+}
+
+ndk::ScopedAStatus Module::getAudioPortConfigs(std::vector<AudioPortConfig>* _aidl_return) {
+    *_aidl_return = getConfig().portConfigs;
+    LOG(DEBUG) << __func__ << ": returning " << _aidl_return->size() << " port configs";
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus Module::getAudioPorts(std::vector<AudioPort>* _aidl_return) {
+    *_aidl_return = getConfig().ports;
+    LOG(DEBUG) << __func__ << ": returning " << _aidl_return->size() << " ports";
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus Module::getAudioRoutes(std::vector<AudioRoute>* _aidl_return) {
+    *_aidl_return = getConfig().routes;
+    LOG(DEBUG) << __func__ << ": returning " << _aidl_return->size() << " routes";
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus Module::openInputStream(int32_t in_portConfigId,
+                                           const SinkMetadata& in_sinkMetadata,
+                                           std::shared_ptr<IStreamIn>* _aidl_return) {
+    auto& configs = getConfig().portConfigs;
+    auto portConfigIt = findById<AudioPortConfig>(configs, in_portConfigId);
+    if (portConfigIt == configs.end()) {
+        LOG(ERROR) << __func__ << ": existing port config id " << in_portConfigId << " not found";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    const int32_t portId = portConfigIt->portId;
+    // In our implementation, configs of mix ports always have unique IDs.
+    CHECK(portId != in_portConfigId);
+    auto& ports = getConfig().ports;
+    auto portIt = findById<AudioPort>(ports, portId);
+    if (portIt == ports.end()) {
+        LOG(ERROR) << __func__ << ": port id " << portId << " used by port config id "
+                   << in_portConfigId << " not found";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    if (portIt->flags.getTag() != AudioIoFlags::Tag::input ||
+        portIt->ext.getTag() != AudioPortExt::Tag::mix) {
+        LOG(ERROR) << __func__ << ": port config id " << in_portConfigId
+                   << " does not correspond to an input mix port";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    if (mStreams.count(in_portConfigId) != 0) {
+        LOG(ERROR) << __func__ << ": port config id " << in_portConfigId
+                   << " already has a stream opened on it";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    const int32_t maxOpenStreamCount = portIt->ext.get<AudioPortExt::Tag::mix>().maxOpenStreamCount;
+    if (maxOpenStreamCount != 0 && mStreams.count(portId) >= maxOpenStreamCount) {
+        LOG(ERROR) << __func__ << ": port id " << portId
+                   << " has already reached maximum allowed opened stream count: "
+                   << maxOpenStreamCount;
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    auto stream = ndk::SharedRefBase::make<StreamIn>(in_sinkMetadata);
+    mStreams.insert(portId, in_portConfigId, StreamWrapper(stream));
+    *_aidl_return = std::move(stream);
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus Module::openOutputStream(int32_t in_portConfigId,
+                                            const SourceMetadata& in_sourceMetadata,
+                                            const std::optional<AudioOffloadInfo>& in_offloadInfo,
+                                            std::shared_ptr<IStreamOut>* _aidl_return) {
+    auto& configs = getConfig().portConfigs;
+    auto portConfigIt = findById<AudioPortConfig>(configs, in_portConfigId);
+    if (portConfigIt == configs.end()) {
+        LOG(ERROR) << __func__ << ": existing port config id " << in_portConfigId << " not found";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    const int32_t portId = portConfigIt->portId;
+    // In our implementation, configs of mix ports always have unique IDs.
+    CHECK(portId != in_portConfigId);
+    auto& ports = getConfig().ports;
+    auto portIt = findById<AudioPort>(ports, portId);
+    if (portIt == ports.end()) {
+        LOG(ERROR) << __func__ << ": port id " << portId << " used by port config id "
+                   << in_portConfigId << " not found";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    if (portIt->flags.getTag() != AudioIoFlags::Tag::output ||
+        portIt->ext.getTag() != AudioPortExt::Tag::mix) {
+        LOG(ERROR) << __func__ << ": port config id " << in_portConfigId
+                   << " does not correspond to an output mix port";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    if (mStreams.count(in_portConfigId) != 0) {
+        LOG(ERROR) << __func__ << ": port config id " << in_portConfigId
+                   << " already has a stream opened on it";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    const int32_t maxOpenStreamCount = portIt->ext.get<AudioPortExt::Tag::mix>().maxOpenStreamCount;
+    if (maxOpenStreamCount != 0 && mStreams.count(portId) >= maxOpenStreamCount) {
+        LOG(ERROR) << __func__ << ": port id " << portId
+                   << " has already reached maximum allowed opened stream count: "
+                   << maxOpenStreamCount;
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    auto stream = ndk::SharedRefBase::make<StreamOut>(in_sourceMetadata, in_offloadInfo);
+    mStreams.insert(portId, in_portConfigId, StreamWrapper(stream));
+    *_aidl_return = std::move(stream);
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus Module::setAudioPatch(const AudioPatch& in_requested, AudioPatch* _aidl_return) {
+    if (in_requested.sourcePortConfigIds.empty()) {
+        LOG(ERROR) << __func__ << ": requested patch has empty sources list";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    if (!all_unique<int32_t>(in_requested.sourcePortConfigIds)) {
+        LOG(ERROR) << __func__ << ": requested patch has duplicate ids in the sources list";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    if (in_requested.sinkPortConfigIds.empty()) {
+        LOG(ERROR) << __func__ << ": requested patch has empty sinks list";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    if (!all_unique<int32_t>(in_requested.sinkPortConfigIds)) {
+        LOG(ERROR) << __func__ << ": requested patch has duplicate ids in the sinks list";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+
+    auto& configs = getConfig().portConfigs;
+    std::vector<int32_t> missingIds;
+    auto sources =
+            selectByIds<AudioPortConfig>(configs, in_requested.sourcePortConfigIds, &missingIds);
+    if (!missingIds.empty()) {
+        LOG(ERROR) << __func__ << ": following source port config ids not found: "
+                   << ::android::internal::ToString(missingIds);
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    auto sinks = selectByIds<AudioPortConfig>(configs, in_requested.sinkPortConfigIds, &missingIds);
+    if (!missingIds.empty()) {
+        LOG(ERROR) << __func__ << ": following sink port config ids not found: "
+                   << ::android::internal::ToString(missingIds);
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    // bool indicates whether a non-exclusive route is available.
+    // If only an exclusive route is available, that means the patch can not be
+    // established if there is any other patch which currently uses the sink port.
+    std::map<int32_t, bool> allowedSinkPorts;
+    auto& routes = getConfig().routes;
+    for (auto src : sources) {
+        for (const auto& r : routes) {
+            const auto& srcs = r.sourcePortIds;
+            if (std::find(srcs.begin(), srcs.end(), src->portId) != srcs.end()) {
+                if (!allowedSinkPorts[r.sinkPortId]) {  // prefer non-exclusive
+                    allowedSinkPorts[r.sinkPortId] = !r.isExclusive;
+                }
+            }
+        }
+    }
+    for (auto sink : sinks) {
+        if (allowedSinkPorts.count(sink->portId) == 0) {
+            LOG(ERROR) << __func__ << ": there is no route to the sink port id " << sink->portId;
+            return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+        }
+    }
+
+    auto& patches = getConfig().patches;
+    auto existing = patches.end();
+    std::optional<decltype(mPatches)> patchesBackup;
+    if (in_requested.id != 0) {
+        existing = findById<AudioPatch>(patches, in_requested.id);
+        if (existing != patches.end()) {
+            patchesBackup = mPatches;
+            cleanUpPatch(existing->id);
+        } else {
+            LOG(ERROR) << __func__ << ": not found existing patch id " << in_requested.id;
+            return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+        }
+    }
+    // Validate the requested patch.
+    for (const auto& [sinkPortId, nonExclusive] : allowedSinkPorts) {
+        if (!nonExclusive && mPatches.count(sinkPortId) != 0) {
+            LOG(ERROR) << __func__ << ": sink port id " << sinkPortId
+                       << "is exclusive and is already used by some other patch";
+            if (patchesBackup.has_value()) {
+                mPatches = std::move(*patchesBackup);
+            }
+            return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+        }
+    }
+    *_aidl_return = in_requested;
+    if (existing == patches.end()) {
+        _aidl_return->id = getConfig().nextPatchId++;
+        patches.push_back(*_aidl_return);
+        existing = patches.begin() + (patches.size() - 1);
+    } else {
+        *existing = *_aidl_return;
+    }
+    registerPatch(*existing);
+    LOG(DEBUG) << __func__ << ": created or updated patch id " << _aidl_return->id;
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus Module::setAudioPortConfig(const AudioPortConfig& in_requested,
+                                              AudioPortConfig* out_suggested, bool* _aidl_return) {
+    LOG(DEBUG) << __func__ << ": requested " << in_requested.toString();
+    auto& configs = getConfig().portConfigs;
+    auto existing = configs.end();
+    if (in_requested.id != 0) {
+        if (existing = findById<AudioPortConfig>(configs, in_requested.id);
+            existing == configs.end()) {
+            LOG(ERROR) << __func__ << ": existing port config id " << in_requested.id
+                       << " not found";
+            return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+        }
+    }
+
+    const int portId = existing != configs.end() ? existing->portId : in_requested.portId;
+    if (portId == 0) {
+        LOG(ERROR) << __func__ << ": input port config does not specify portId";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    auto& ports = getConfig().ports;
+    auto portIt = findById<AudioPort>(ports, portId);
+    if (portIt == ports.end()) {
+        LOG(ERROR) << __func__ << ": input port config points to non-existent portId " << portId;
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    if (existing != configs.end()) {
+        *out_suggested = *existing;
+    } else {
+        AudioPortConfig newConfig;
+        if (generateDefaultPortConfig(*portIt, &newConfig)) {
+            *out_suggested = newConfig;
+        } else {
+            LOG(ERROR) << __func__ << ": unable generate a default config for port " << portId;
+            return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+        }
+    }
+    // From this moment, 'out_suggested' is either an existing port config,
+    // or a new generated config. Now attempt to update it according to the specified
+    // fields of 'in_requested'.
+
+    bool requestedIsValid = true, requestedIsFullySpecified = true;
+
+    AudioIoFlags portFlags = portIt->flags;
+    if (in_requested.flags.has_value()) {
+        if (in_requested.flags.value() != portFlags) {
+            LOG(WARNING) << __func__ << ": requested flags "
+                         << in_requested.flags.value().toString() << " do not match port's "
+                         << portId << " flags " << portFlags.toString();
+            requestedIsValid = false;
+        }
+    } else {
+        requestedIsFullySpecified = false;
+    }
+
+    AudioProfile portProfile;
+    if (in_requested.format.has_value()) {
+        const auto& format = in_requested.format.value();
+        if (findAudioProfile(*portIt, format, &portProfile)) {
+            out_suggested->format = format;
+        } else {
+            LOG(WARNING) << __func__ << ": requested format " << format.toString()
+                         << " is not found in port's " << portId << " profiles";
+            requestedIsValid = false;
+        }
+    } else {
+        requestedIsFullySpecified = false;
+    }
+    if (!findAudioProfile(*portIt, out_suggested->format.value(), &portProfile)) {
+        LOG(ERROR) << __func__ << ": port " << portId << " does not support format "
+                   << out_suggested->format.value().toString() << " anymore";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+
+    if (in_requested.channelMask.has_value()) {
+        const auto& channelMask = in_requested.channelMask.value();
+        if (find(portProfile.channelMasks.begin(), portProfile.channelMasks.end(), channelMask) !=
+            portProfile.channelMasks.end()) {
+            out_suggested->channelMask = channelMask;
+        } else {
+            LOG(WARNING) << __func__ << ": requested channel mask " << channelMask.toString()
+                         << " is not supported for the format " << portProfile.format.toString()
+                         << " by the port " << portId;
+            requestedIsValid = false;
+        }
+    } else {
+        requestedIsFullySpecified = false;
+    }
+
+    if (in_requested.sampleRate.has_value()) {
+        const auto& sampleRate = in_requested.sampleRate.value();
+        if (find(portProfile.sampleRates.begin(), portProfile.sampleRates.end(),
+                 sampleRate.value) != portProfile.sampleRates.end()) {
+            out_suggested->sampleRate = sampleRate;
+        } else {
+            LOG(WARNING) << __func__ << ": requested sample rate " << sampleRate.value
+                         << " is not supported for the format " << portProfile.format.toString()
+                         << " by the port " << portId;
+            requestedIsValid = false;
+        }
+    } else {
+        requestedIsFullySpecified = false;
+    }
+
+    if (in_requested.gain.has_value()) {
+        // Let's pretend that gain can always be applied.
+        out_suggested->gain = in_requested.gain.value();
+    }
+
+    if (existing == configs.end() && requestedIsValid && requestedIsFullySpecified) {
+        out_suggested->id = getConfig().nextPortId++;
+        configs.push_back(*out_suggested);
+        *_aidl_return = true;
+        LOG(DEBUG) << __func__ << ": created new port config " << out_suggested->toString();
+    } else if (existing != configs.end() && requestedIsValid) {
+        *existing = *out_suggested;
+        *_aidl_return = true;
+        LOG(DEBUG) << __func__ << ": updated port config " << out_suggested->toString();
+    } else {
+        LOG(DEBUG) << __func__ << ": not applied; existing config ? " << (existing != configs.end())
+                   << "; requested is valid? " << requestedIsValid << ", fully specified? "
+                   << requestedIsFullySpecified;
+        *_aidl_return = false;
+    }
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus Module::resetAudioPatch(int32_t in_patchId) {
+    auto& patches = getConfig().patches;
+    auto patchIt = findById<AudioPatch>(patches, in_patchId);
+    if (patchIt != patches.end()) {
+        cleanUpPatch(patchIt->id);
+        patches.erase(patchIt);
+        LOG(DEBUG) << __func__ << ": erased patch " << in_patchId;
+        return ndk::ScopedAStatus::ok();
+    }
+    LOG(ERROR) << __func__ << ": patch id " << in_patchId << " not found";
+    return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+}
+
+ndk::ScopedAStatus Module::resetAudioPortConfig(int32_t in_portConfigId) {
+    auto& configs = getConfig().portConfigs;
+    auto configIt = findById<AudioPortConfig>(configs, in_portConfigId);
+    if (configIt != configs.end()) {
+        if (mStreams.count(in_portConfigId) != 0) {
+            LOG(ERROR) << __func__ << ": port config id " << in_portConfigId
+                       << " has a stream opened on it";
+            return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+        }
+        auto patchIt = mPatches.find(in_portConfigId);
+        if (patchIt != mPatches.end()) {
+            LOG(ERROR) << __func__ << ": port config id " << in_portConfigId
+                       << " is used by the patch with id " << patchIt->second;
+            return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+        }
+        auto& initials = getConfig().initialConfigs;
+        auto initialIt = findById<AudioPortConfig>(initials, in_portConfigId);
+        if (initialIt == initials.end()) {
+            configs.erase(configIt);
+            LOG(DEBUG) << __func__ << ": erased port config " << in_portConfigId;
+        } else if (*configIt != *initialIt) {
+            *configIt = *initialIt;
+            LOG(DEBUG) << __func__ << ": reset port config " << in_portConfigId;
+        }
+        return ndk::ScopedAStatus::ok();
+    }
+    LOG(ERROR) << __func__ << ": port config id " << in_portConfigId << " not found";
+    return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+}
+
+}  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/Stream.cpp b/audio/aidl/default/Stream.cpp
new file mode 100644
index 0000000..e16b2c6
--- /dev/null
+++ b/audio/aidl/default/Stream.cpp
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2022 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 "AHAL_Stream"
+#define LOG_NDEBUG 0
+#include <android-base/logging.h>
+
+#include "core-impl/Stream.h"
+
+using aidl::android::hardware::audio::common::SinkMetadata;
+using aidl::android::hardware::audio::common::SourceMetadata;
+using aidl::android::media::audio::common::AudioOffloadInfo;
+
+namespace aidl::android::hardware::audio::core {
+
+StreamIn::StreamIn(const SinkMetadata& sinkMetadata) : mMetadata(sinkMetadata) {}
+
+ndk::ScopedAStatus StreamIn::close() {
+    LOG(DEBUG) << __func__;
+    if (!mIsClosed) {
+        mIsClosed = true;
+        return ndk::ScopedAStatus::ok();
+    } else {
+        LOG(ERROR) << __func__ << ": stream was already closed";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+}
+
+ndk::ScopedAStatus StreamIn::updateMetadata(const SinkMetadata& in_sinkMetadata) {
+    LOG(DEBUG) << __func__;
+    if (!mIsClosed) {
+        mMetadata = in_sinkMetadata;
+        return ndk::ScopedAStatus::ok();
+    }
+    LOG(ERROR) << __func__ << ": stream was closed";
+    return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+}
+
+StreamOut::StreamOut(const SourceMetadata& sourceMetadata,
+                     const std::optional<AudioOffloadInfo>& offloadInfo)
+    : mMetadata(sourceMetadata), mOffloadInfo(offloadInfo) {}
+
+ndk::ScopedAStatus StreamOut::close() {
+    LOG(DEBUG) << __func__;
+    if (!mIsClosed) {
+        mIsClosed = true;
+        return ndk::ScopedAStatus::ok();
+    }
+    LOG(ERROR) << __func__ << ": stream was already closed";
+    return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+}
+
+ndk::ScopedAStatus StreamOut::updateMetadata(const SourceMetadata& in_sourceMetadata) {
+    LOG(DEBUG) << __func__;
+    if (!mIsClosed) {
+        mMetadata = in_sourceMetadata;
+        return ndk::ScopedAStatus::ok();
+    }
+    LOG(ERROR) << __func__ << ": stream was closed";
+    return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+}
+
+}  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/android.hardware.audio.service-aidl.example.rc b/audio/aidl/default/android.hardware.audio.service-aidl.example.rc
new file mode 100644
index 0000000..02a9c37
--- /dev/null
+++ b/audio/aidl/default/android.hardware.audio.service-aidl.example.rc
@@ -0,0 +1,9 @@
+service vendor.audio-hal-aidl /vendor/bin/hw/android.hardware.audio.service-aidl.example
+    class hal
+    user audioserver
+    # media gid needed for /dev/fm (radio) and for /data/misc/media (tee)
+    group audio camera drmrpc inet media mediadrm net_bt net_bt_admin net_bw_acct wakelock context_hub
+    capabilities BLOCK_SUSPEND
+    ioprio rt 4
+    task_profiles ProcessCapacityHigh HighPerformance
+    onrestart restart audioserver
diff --git a/audio/aidl/default/android.hardware.audio.service-aidl.xml b/audio/aidl/default/android.hardware.audio.service-aidl.xml
new file mode 100644
index 0000000..bb4b01a
--- /dev/null
+++ b/audio/aidl/default/android.hardware.audio.service-aidl.xml
@@ -0,0 +1,12 @@
+<manifest version="1.0" type="device">
+  <hal format="aidl">
+    <name>android.hardware.audio.core</name>
+    <version>1</version>
+    <fqname>IModule/default</fqname>
+  </hal>
+  <hal format="aidl">
+    <name>android.hardware.audio.core</name>
+    <version>1</version>
+    <fqname>IConfig/default</fqname>
+  </hal>
+</manifest>
diff --git a/audio/aidl/default/include/core-impl/Config.h b/audio/aidl/default/include/core-impl/Config.h
new file mode 100644
index 0000000..b62a14b
--- /dev/null
+++ b/audio/aidl/default/include/core-impl/Config.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2022 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 <aidl/android/hardware/audio/core/BnConfig.h>
+
+namespace aidl::android::hardware::audio::core {
+
+class Config : public BnConfig {};
+
+}  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/include/core-impl/Configuration.h b/audio/aidl/default/include/core-impl/Configuration.h
new file mode 100644
index 0000000..17e342d
--- /dev/null
+++ b/audio/aidl/default/include/core-impl/Configuration.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2022 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 <vector>
+
+#include <aidl/android/hardware/audio/core/AudioPatch.h>
+#include <aidl/android/hardware/audio/core/AudioRoute.h>
+#include <aidl/android/media/audio/common/AudioPort.h>
+#include <aidl/android/media/audio/common/AudioPortConfig.h>
+
+namespace aidl::android::hardware::audio::core::internal {
+
+struct Configuration {
+    std::vector<::aidl::android::media::audio::common::AudioPort> ports;
+    std::vector<::aidl::android::media::audio::common::AudioPortConfig> portConfigs;
+    std::vector<::aidl::android::media::audio::common::AudioPortConfig> initialConfigs;
+    std::vector<AudioRoute> routes;
+    std::vector<AudioPatch> patches;
+    int32_t nextPortId = 1;
+    int32_t nextPatchId = 1;
+};
+
+Configuration& getNullPrimaryConfiguration();
+
+}  // namespace aidl::android::hardware::audio::core::internal
diff --git a/audio/aidl/default/include/core-impl/Module.h b/audio/aidl/default/include/core-impl/Module.h
new file mode 100644
index 0000000..359626c
--- /dev/null
+++ b/audio/aidl/default/include/core-impl/Module.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2022 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 <map>
+#include <memory>
+
+#include <aidl/android/hardware/audio/core/BnModule.h>
+
+#include "core-impl/Configuration.h"
+#include "core-impl/Stream.h"
+
+namespace aidl::android::hardware::audio::core {
+
+class Module : public BnModule {
+    ndk::ScopedAStatus getAudioPatches(std::vector<AudioPatch>* _aidl_return) override;
+    ndk::ScopedAStatus getAudioPort(
+            int32_t in_portId,
+            ::aidl::android::media::audio::common::AudioPort* _aidl_return) override;
+    ndk::ScopedAStatus getAudioPortConfigs(
+            std::vector<::aidl::android::media::audio::common::AudioPortConfig>* _aidl_return)
+            override;
+    ndk::ScopedAStatus getAudioPorts(
+            std::vector<::aidl::android::media::audio::common::AudioPort>* _aidl_return) override;
+    ndk::ScopedAStatus getAudioRoutes(std::vector<AudioRoute>* _aidl_return) override;
+    ndk::ScopedAStatus openInputStream(
+            int32_t in_portConfigId,
+            const ::aidl::android::hardware::audio::common::SinkMetadata& in_sinkMetadata,
+            std::shared_ptr<IStreamIn>* _aidl_return) override;
+    ndk::ScopedAStatus openOutputStream(
+            int32_t in_portConfigId,
+            const ::aidl::android::hardware::audio::common::SourceMetadata& in_sourceMetadata,
+            const std::optional<::aidl::android::media::audio::common::AudioOffloadInfo>&
+                    in_offloadInfo,
+            std::shared_ptr<IStreamOut>* _aidl_return) override;
+    ndk::ScopedAStatus setAudioPatch(const AudioPatch& in_requested,
+                                     AudioPatch* _aidl_return) override;
+    ndk::ScopedAStatus setAudioPortConfig(
+            const ::aidl::android::media::audio::common::AudioPortConfig& in_requested,
+            ::aidl::android::media::audio::common::AudioPortConfig* out_suggested,
+            bool* _aidl_return) override;
+    ndk::ScopedAStatus resetAudioPatch(int32_t in_patchId) override;
+    ndk::ScopedAStatus resetAudioPortConfig(int32_t in_portConfigId) override;
+
+  private:
+    void cleanUpPatch(int32_t patchId);
+    void cleanUpPatches(int32_t portConfigId);
+    internal::Configuration& getConfig();
+    void registerPatch(const AudioPatch& patch);
+
+    std::unique_ptr<internal::Configuration> mConfig;
+    Streams mStreams;
+    // Maps port ids and port config ids to patch ids.
+    // Multimap because both ports and configs can be used by multiple patches.
+    std::multimap<int32_t, int32_t> mPatches;
+};
+
+}  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/include/core-impl/Stream.h b/audio/aidl/default/include/core-impl/Stream.h
new file mode 100644
index 0000000..87104dd
--- /dev/null
+++ b/audio/aidl/default/include/core-impl/Stream.h
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2022 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 <map>
+#include <optional>
+#include <variant>
+
+#include <aidl/android/hardware/audio/common/SinkMetadata.h>
+#include <aidl/android/hardware/audio/common/SourceMetadata.h>
+#include <aidl/android/hardware/audio/core/BnStreamIn.h>
+#include <aidl/android/hardware/audio/core/BnStreamOut.h>
+#include <aidl/android/media/audio/common/AudioOffloadInfo.h>
+
+#include "core-impl/utils.h"
+
+namespace aidl::android::hardware::audio::core {
+
+class StreamIn : public BnStreamIn {
+    ndk::ScopedAStatus close() override;
+    ndk::ScopedAStatus updateMetadata(
+            const ::aidl::android::hardware::audio::common::SinkMetadata& in_sinkMetadata) override;
+
+  public:
+    explicit StreamIn(const ::aidl::android::hardware::audio::common::SinkMetadata& sinkMetadata);
+    bool isClosed() const { return mIsClosed; }
+
+  private:
+    ::aidl::android::hardware::audio::common::SinkMetadata mMetadata;
+    bool mIsClosed = false;
+};
+
+class StreamOut : public BnStreamOut {
+    ndk::ScopedAStatus close() override;
+    ndk::ScopedAStatus updateMetadata(
+            const ::aidl::android::hardware::audio::common::SourceMetadata& in_sourceMetadata)
+            override;
+
+  public:
+    StreamOut(const ::aidl::android::hardware::audio::common::SourceMetadata& sourceMetadata,
+              const std::optional<::aidl::android::media::audio::common::AudioOffloadInfo>&
+                      offloadInfo);
+    bool isClosed() const { return mIsClosed; }
+
+  private:
+    ::aidl::android::hardware::audio::common::SourceMetadata mMetadata;
+    std::optional<::aidl::android::media::audio::common::AudioOffloadInfo> mOffloadInfo;
+    bool mIsClosed = false;
+};
+
+class StreamWrapper {
+  public:
+    explicit StreamWrapper(std::shared_ptr<StreamIn> streamIn) : mStream(streamIn) {}
+    explicit StreamWrapper(std::shared_ptr<StreamOut> streamOut) : mStream(streamOut) {}
+    bool isStreamOpen() const {
+        return std::visit(
+                [](auto&& ws) -> bool {
+                    auto s = ws.lock();
+                    return s && !s->isClosed();
+                },
+                mStream);
+    }
+
+  private:
+    std::variant<std::weak_ptr<StreamIn>, std::weak_ptr<StreamOut>> mStream;
+};
+
+class Streams {
+  public:
+    Streams() = default;
+    Streams(const Streams&) = delete;
+    Streams& operator=(const Streams&) = delete;
+    size_t count(int32_t id) {
+        // Streams do not remove themselves from the collection on close.
+        erase_if(mStreams, [](const auto& pair) { return !pair.second.isStreamOpen(); });
+        return mStreams.count(id);
+    }
+    void insert(int32_t portId, int32_t portConfigId, StreamWrapper sw) {
+        mStreams.insert(std::pair{portConfigId, sw});
+        mStreams.insert(std::pair{portId, sw});
+    }
+
+  private:
+    // Maps port ids and port config ids to streams. Multimap because a port
+    // (not port config) can have multiple streams opened on it.
+    std::multimap<int32_t, StreamWrapper> mStreams;
+};
+
+}  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/include/core-impl/utils.h b/audio/aidl/default/include/core-impl/utils.h
new file mode 100644
index 0000000..7101012
--- /dev/null
+++ b/audio/aidl/default/include/core-impl/utils.h
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2022 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 <algorithm>
+#include <set>
+#include <vector>
+
+namespace aidl::android::hardware::audio::core {
+
+// Return whether all the elements in the vector are unique.
+template <typename T>
+bool all_unique(const std::vector<T>& v) {
+    return std::set<T>(v.begin(), v.end()).size() == v.size();
+}
+
+// Erase all the specified elements from a map.
+template <typename C, typename V>
+auto erase_all(C& c, const V& keys) {
+    auto oldSize = c.size();
+    for (auto& k : keys) {
+        c.erase(k);
+    }
+    return oldSize - c.size();
+}
+
+// Erase all the elements in the map that satisfy the provided predicate.
+template <typename C, typename P>
+auto erase_if(C& c, P pred) {
+    auto oldSize = c.size();
+    for (auto it = c.begin(), last = c.end(); it != last;) {
+        if (pred(*it)) {
+            it = c.erase(it);
+        } else {
+            ++it;
+        }
+    }
+    return oldSize - c.size();
+}
+
+// Erase all the elements in the map that have specified values.
+template <typename C, typename V>
+auto erase_all_values(C& c, const V& values) {
+    return erase_if(c, [values](const auto& pair) { return values.count(pair.second) != 0; });
+}
+
+// Return non-zero count of elements for any of the provided keys.
+template <typename M, typename V>
+size_t count_any(const M& m, const V& keys) {
+    for (auto& k : keys) {
+        if (size_t c = m.count(k); c != 0) return c;
+    }
+    return 0;
+}
+
+// Assuming that M is a map whose values have an 'id' field,
+// find an element with the specified id.
+template <typename M>
+auto findById(M& m, int32_t id) {
+    return std::find_if(m.begin(), m.end(), [&](const auto& p) { return p.second.id == id; });
+}
+
+// Assuming that the vector contains elements with an 'id' field,
+// find an element with the specified id.
+template <typename T>
+auto findById(std::vector<T>& v, int32_t id) {
+    return std::find_if(v.begin(), v.end(), [&](const auto& e) { return e.id == id; });
+}
+
+// Return elements from the vector that have specified ids, also
+// optionally return which ids were not found.
+template <typename T>
+std::vector<T*> selectByIds(std::vector<T>& v, const std::vector<int32_t>& ids,
+                            std::vector<int32_t>* missingIds = nullptr) {
+    std::vector<T*> result;
+    std::set<int32_t> idsSet(ids.begin(), ids.end());
+    for (size_t i = 0; i < v.size(); ++i) {
+        T& e = v[i];
+        if (idsSet.count(e.id) != 0) {
+            result.push_back(&v[i]);
+            idsSet.erase(e.id);
+        }
+    }
+    if (missingIds) {
+        *missingIds = std::vector(idsSet.begin(), idsSet.end());
+    }
+    return result;
+}
+
+}  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/main.cpp b/audio/aidl/default/main.cpp
new file mode 100644
index 0000000..0de6047
--- /dev/null
+++ b/audio/aidl/default/main.cpp
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2022 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 "core-impl/Config.h"
+#include "core-impl/Module.h"
+
+#include <android-base/logging.h>
+#include <android/binder_manager.h>
+#include <android/binder_process.h>
+
+using aidl::android::hardware::audio::core::Config;
+using aidl::android::hardware::audio::core::Module;
+
+int main() {
+    ABinderProcess_setThreadPoolMaxThreadCount(16);
+
+    // make the default config service
+    auto config = ndk::SharedRefBase::make<Config>();
+    const std::string configName = std::string() + Config::descriptor + "/default";
+    binder_status_t status =
+            AServiceManager_addService(config->asBinder().get(), configName.c_str());
+    CHECK(status == STATUS_OK);
+
+    // make the default module
+    auto moduleDefault = ndk::SharedRefBase::make<Module>();
+    const std::string moduleDefaultName = std::string() + Module::descriptor + "/default";
+    status = AServiceManager_addService(moduleDefault->asBinder().get(), moduleDefaultName.c_str());
+    CHECK(status == STATUS_OK);
+
+    ABinderProcess_joinThreadPool();
+    return EXIT_FAILURE;  // should not reach
+}