Implementation of Bluetooth Audio HAL interface v2

This is the default implementation of Bluetooth Audio Hal v2, and 3
providers are defined.

* BluetoothAudioProvider is the default provider, which is a stub when
  no SessionType matched.
* A2dpSoftwareAudioProvider uses to replace the old A2DP legacy module
  and uses IPC via HIDL interface between Bluetooth stack and Audio HAL.
* HearingAidAudioProvider uses to replace the Hearing Aids module which
  uses UNIX socket as IPC and now there is HIDL based interface.

There is also a shared library named "libbluetooth_audio_session.so" to
provide the linkage directly between this HIDL and its HAL module,
bluetooth_audio. With this library, we can break the library dependency
and guarantee those symbols of libraries while compiling.

Bug: 111519504
Bug: 122503379
Test: boot and manual test

Change-Id: I54d86291482b7fb041a3ac3e171b68a4ed7bfa07
diff --git a/bluetooth/audio/2.0/default/HearingAidAudioProvider.cpp b/bluetooth/audio/2.0/default/HearingAidAudioProvider.cpp
new file mode 100644
index 0000000..e91cf8a
--- /dev/null
+++ b/bluetooth/audio/2.0/default/HearingAidAudioProvider.cpp
@@ -0,0 +1,106 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "BTAudioProviderHearingAid"
+
+#include <android-base/logging.h>
+
+#include "BluetoothAudioSessionReport.h"
+#include "BluetoothAudioSupportedCodecsDB.h"
+#include "HearingAidAudioProvider.h"
+
+namespace android {
+namespace hardware {
+namespace bluetooth {
+namespace audio {
+namespace V2_0 {
+namespace implementation {
+
+using ::android::bluetooth::audio::BluetoothAudioSessionReport;
+using ::android::hardware::Void;
+
+static constexpr uint32_t kPcmFrameSize = 4;  // 16 bits per sample / stereo
+static constexpr uint32_t kPcmFrameCount = 128;
+static constexpr uint32_t kRtpFrameSize = kPcmFrameSize * kPcmFrameCount;
+static constexpr uint32_t kRtpFrameCount = 7;  // max counts by 1 tick (20ms)
+static constexpr uint32_t kBufferSize = kRtpFrameSize * kRtpFrameCount;
+static constexpr uint32_t kBufferCount = 1;  // single buffer
+static constexpr uint32_t kDataMqSize = kBufferSize * kBufferCount;
+
+HearingAidAudioProvider::HearingAidAudioProvider()
+    : BluetoothAudioProvider(), mDataMQ(nullptr) {
+  LOG(INFO) << __func__ << " - size of audio buffer " << kDataMqSize
+            << " byte(s)";
+  std::unique_ptr<DataMQ> tempDataMQ(
+      new DataMQ(kDataMqSize, /* EventFlag */ true));
+  if (tempDataMQ && tempDataMQ->isValid()) {
+    mDataMQ = std::move(tempDataMQ);
+    session_type_ = SessionType::HEARING_AID_SOFTWARE_ENCODING_DATAPATH;
+  } else {
+    ALOGE_IF(!tempDataMQ, "failed to allocate data MQ");
+    ALOGE_IF(tempDataMQ && !tempDataMQ->isValid(), "data MQ is invalid");
+  }
+}
+
+bool HearingAidAudioProvider::isValid(const SessionType& sessionType) {
+  return (sessionType == session_type_ && mDataMQ && mDataMQ->isValid());
+}
+
+Return<void> HearingAidAudioProvider::startSession(
+    const sp<IBluetoothAudioPort>& hostIf,
+    const AudioConfiguration& audioConfig, startSession_cb _hidl_cb) {
+  /**
+   * Initialize the audio platform if audioConfiguration is supported.
+   * Save the the IBluetoothAudioPort interface, so that it can be used
+   * later to send stream control commands to the HAL client, based on
+   * interaction with Audio framework.
+   */
+  if (audioConfig.getDiscriminator() !=
+      AudioConfiguration::hidl_discriminator::pcmConfig) {
+    LOG(WARNING) << __func__
+                 << " - Invalid Audio Configuration=" << toString(audioConfig);
+    _hidl_cb(BluetoothAudioStatus::UNSUPPORTED_CODEC_CONFIGURATION,
+             DataMQ::Descriptor());
+    return Void();
+  } else if (!android::bluetooth::audio::IsSoftwarePcmConfigurationValid(
+                 audioConfig.pcmConfig())) {
+    LOG(WARNING) << __func__ << " - Unsupported PCM Configuration="
+                 << toString(audioConfig.pcmConfig());
+    _hidl_cb(BluetoothAudioStatus::UNSUPPORTED_CODEC_CONFIGURATION,
+             DataMQ::Descriptor());
+    return Void();
+  }
+
+  return BluetoothAudioProvider::startSession(hostIf, audioConfig, _hidl_cb);
+}
+
+Return<void> HearingAidAudioProvider::onSessionReady(startSession_cb _hidl_cb) {
+  if (mDataMQ && mDataMQ->isValid()) {
+    BluetoothAudioSessionReport::OnSessionStarted(
+        session_type_, stack_iface_, mDataMQ->getDesc(), audio_config_);
+    _hidl_cb(BluetoothAudioStatus::SUCCESS, *mDataMQ->getDesc());
+  } else {
+    _hidl_cb(BluetoothAudioStatus::FAILURE, DataMQ::Descriptor());
+  }
+  return Void();
+}
+
+}  // namespace implementation
+}  // namespace V2_0
+}  // namespace audio
+}  // namespace bluetooth
+}  // namespace hardware
+}  // namespace android