diff --git a/audio/aidl/default/primary/PrimaryMixer.cpp b/audio/aidl/default/primary/PrimaryMixer.cpp
new file mode 100644
index 0000000..577d010
--- /dev/null
+++ b/audio/aidl/default/primary/PrimaryMixer.cpp
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2023 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_PrimaryMixer"
+
+#include "PrimaryMixer.h"
+
+namespace aidl::android::hardware::audio::core::primary {
+
+// static
+PrimaryMixer& PrimaryMixer::getInstance() {
+    static PrimaryMixer gInstance;
+    return gInstance;
+}
+
+}  // namespace aidl::android::hardware::audio::core::primary
diff --git a/audio/aidl/default/primary/PrimaryMixer.h b/audio/aidl/default/primary/PrimaryMixer.h
new file mode 100644
index 0000000..3806428
--- /dev/null
+++ b/audio/aidl/default/primary/PrimaryMixer.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2023 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 <mutex>
+#include <vector>
+
+#include <android-base/thread_annotations.h>
+#include <android/binder_auto_utils.h>
+
+#include "alsa/Mixer.h"
+
+namespace aidl::android::hardware::audio::core::primary {
+
+class PrimaryMixer : public alsa::Mixer {
+  public:
+    static constexpr int kAlsaCard = 0;
+    static constexpr int kAlsaDevice = 0;
+
+    static PrimaryMixer& getInstance();
+
+  private:
+    PrimaryMixer() : alsa::Mixer(kAlsaCard) {}
+};
+
+}  // namespace aidl::android::hardware::audio::core::primary
diff --git a/audio/aidl/default/primary/StreamPrimary.cpp b/audio/aidl/default/primary/StreamPrimary.cpp
new file mode 100644
index 0000000..e01be8a
--- /dev/null
+++ b/audio/aidl/default/primary/StreamPrimary.cpp
@@ -0,0 +1,186 @@
+/*
+ * Copyright (C) 2023 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 <limits>
+
+#define LOG_TAG "AHAL_StreamPrimary"
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <error/expected_utils.h>
+
+#include "PrimaryMixer.h"
+#include "core-impl/StreamPrimary.h"
+#include "core-impl/StreamStub.h"
+
+using aidl::android::hardware::audio::common::SinkMetadata;
+using aidl::android::hardware::audio::common::SourceMetadata;
+using aidl::android::media::audio::common::AudioDevice;
+using aidl::android::media::audio::common::AudioDeviceDescription;
+using aidl::android::media::audio::common::AudioDeviceType;
+using aidl::android::media::audio::common::AudioOffloadInfo;
+using aidl::android::media::audio::common::MicrophoneInfo;
+using android::base::GetBoolProperty;
+
+namespace aidl::android::hardware::audio::core {
+
+StreamPrimary::StreamPrimary(StreamContext* context, const Metadata& metadata)
+    : StreamAlsa(context, metadata, 3 /*readWriteRetries*/), mIsInput(isInput(metadata)) {}
+
+std::vector<alsa::DeviceProfile> StreamPrimary::getDeviceProfiles() {
+    static const std::vector<alsa::DeviceProfile> kBuiltInSource{
+            alsa::DeviceProfile{.card = primary::PrimaryMixer::kAlsaCard,
+                                .device = primary::PrimaryMixer::kAlsaDevice,
+                                .direction = PCM_IN,
+                                .isExternal = false}};
+    static const std::vector<alsa::DeviceProfile> kBuiltInSink{
+            alsa::DeviceProfile{.card = primary::PrimaryMixer::kAlsaCard,
+                                .device = primary::PrimaryMixer::kAlsaDevice,
+                                .direction = PCM_OUT,
+                                .isExternal = false}};
+    return mIsInput ? kBuiltInSource : kBuiltInSink;
+}
+
+StreamInPrimary::StreamInPrimary(StreamContext&& context, const SinkMetadata& sinkMetadata,
+                                 const std::vector<MicrophoneInfo>& microphones)
+    : StreamIn(std::move(context), microphones),
+      StreamSwitcher(&mContextInstance, sinkMetadata),
+      StreamInHwGainHelper(&mContextInstance) {}
+
+bool StreamInPrimary::useStubStream(const AudioDevice& device) {
+    static const bool kSimulateInput =
+            GetBoolProperty("ro.boot.audio.tinyalsa.simulate_input", false);
+    return kSimulateInput || device.type.type == AudioDeviceType::IN_TELEPHONY_RX ||
+           device.type.type == AudioDeviceType::IN_FM_TUNER ||
+           device.type.connection == AudioDeviceDescription::CONNECTION_BUS;
+}
+
+StreamSwitcher::DeviceSwitchBehavior StreamInPrimary::switchCurrentStream(
+        const std::vector<::aidl::android::media::audio::common::AudioDevice>& devices) {
+    LOG(DEBUG) << __func__;
+    if (devices.size() > 1) {
+        LOG(ERROR) << __func__ << ": primary stream can only be connected to one device, got: "
+                   << devices.size();
+        return DeviceSwitchBehavior::UNSUPPORTED_DEVICES;
+    }
+    if (devices.empty() || useStubStream(devices[0]) == isStubStream()) {
+        return DeviceSwitchBehavior::USE_CURRENT_STREAM;
+    }
+    return DeviceSwitchBehavior::CREATE_NEW_STREAM;
+}
+
+std::unique_ptr<StreamCommonInterfaceEx> StreamInPrimary::createNewStream(
+        const std::vector<::aidl::android::media::audio::common::AudioDevice>& devices,
+        StreamContext* context, const Metadata& metadata) {
+    if (devices.empty()) {
+        LOG(FATAL) << __func__ << ": called with empty devices";  // see 'switchCurrentStream'
+    }
+    if (useStubStream(devices[0])) {
+        return std::unique_ptr<StreamCommonInterfaceEx>(
+                new InnerStreamWrapper<StreamStub>(context, metadata));
+    }
+    return std::unique_ptr<StreamCommonInterfaceEx>(
+            new InnerStreamWrapper<StreamPrimary>(context, metadata));
+}
+
+ndk::ScopedAStatus StreamInPrimary::getHwGain(std::vector<float>* _aidl_return) {
+    if (isStubStream()) {
+        return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
+    }
+    return getHwGainImpl(_aidl_return);
+}
+
+ndk::ScopedAStatus StreamInPrimary::setHwGain(const std::vector<float>& in_channelGains) {
+    if (isStubStream()) {
+        LOG(DEBUG) << __func__ << ": gains " << ::android::internal::ToString(in_channelGains);
+        return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
+    }
+    auto currentGains = mHwGains;
+    RETURN_STATUS_IF_ERROR(setHwGainImpl(in_channelGains));
+    if (in_channelGains.size() < 1) {
+        LOG(FATAL) << __func__ << ": unexpected gain vector size: " << in_channelGains.size();
+    }
+    if (auto status = primary::PrimaryMixer::getInstance().setMicGain(in_channelGains[0]);
+        !status.isOk()) {
+        mHwGains = currentGains;
+        return status;
+    }
+    return ndk::ScopedAStatus::ok();
+}
+
+StreamOutPrimary::StreamOutPrimary(StreamContext&& context, const SourceMetadata& sourceMetadata,
+                                   const std::optional<AudioOffloadInfo>& offloadInfo)
+    : StreamOut(std::move(context), offloadInfo),
+      StreamSwitcher(&mContextInstance, sourceMetadata),
+      StreamOutHwVolumeHelper(&mContextInstance) {}
+
+bool StreamOutPrimary::useStubStream(const AudioDevice& device) {
+    static const bool kSimulateOutput =
+            GetBoolProperty("ro.boot.audio.tinyalsa.ignore_output", false);
+    return kSimulateOutput || device.type.type == AudioDeviceType::OUT_TELEPHONY_TX ||
+           device.type.connection == AudioDeviceDescription::CONNECTION_BUS;
+}
+
+StreamSwitcher::DeviceSwitchBehavior StreamOutPrimary::switchCurrentStream(
+        const std::vector<::aidl::android::media::audio::common::AudioDevice>& devices) {
+    LOG(DEBUG) << __func__;
+    if (devices.size() > 1) {
+        LOG(ERROR) << __func__ << ": primary stream can only be connected to one device, got: "
+                   << devices.size();
+        return DeviceSwitchBehavior::UNSUPPORTED_DEVICES;
+    }
+    if (devices.empty() || useStubStream(devices[0]) == isStubStream()) {
+        return DeviceSwitchBehavior::USE_CURRENT_STREAM;
+    }
+    return DeviceSwitchBehavior::CREATE_NEW_STREAM;
+}
+
+std::unique_ptr<StreamCommonInterfaceEx> StreamOutPrimary::createNewStream(
+        const std::vector<::aidl::android::media::audio::common::AudioDevice>& devices,
+        StreamContext* context, const Metadata& metadata) {
+    if (devices.empty()) {
+        LOG(FATAL) << __func__ << ": called with empty devices";  // see 'switchCurrentStream'
+    }
+    if (useStubStream(devices[0])) {
+        return std::unique_ptr<StreamCommonInterfaceEx>(
+                new InnerStreamWrapper<StreamStub>(context, metadata));
+    }
+    return std::unique_ptr<StreamCommonInterfaceEx>(
+            new InnerStreamWrapper<StreamPrimary>(context, metadata));
+}
+
+ndk::ScopedAStatus StreamOutPrimary::getHwVolume(std::vector<float>* _aidl_return) {
+    if (isStubStream()) {
+        return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
+    }
+    return getHwVolumeImpl(_aidl_return);
+}
+
+ndk::ScopedAStatus StreamOutPrimary::setHwVolume(const std::vector<float>& in_channelVolumes) {
+    if (isStubStream()) {
+        LOG(DEBUG) << __func__ << ": volumes " << ::android::internal::ToString(in_channelVolumes);
+        return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
+    }
+    auto currentVolumes = mHwVolumes;
+    RETURN_STATUS_IF_ERROR(setHwVolumeImpl(in_channelVolumes));
+    if (auto status = primary::PrimaryMixer::getInstance().setVolumes(in_channelVolumes);
+        !status.isOk()) {
+        mHwVolumes = currentVolumes;
+        return status;
+    }
+    return ndk::ScopedAStatus::ok();
+}
+
+}  // namespace aidl::android::hardware::audio::core