Downmix: Add AIDL placeholder implementation and vts test

Bug: 258124419
Test: atest VtsHalDownmixTargetTest

Change-Id: I6c202d474b738e0e0d242dc91cafa3892b9e9987
diff --git a/audio/aidl/default/downmix/DownmixSw.h b/audio/aidl/default/downmix/DownmixSw.h
new file mode 100644
index 0000000..51546c1
--- /dev/null
+++ b/audio/aidl/default/downmix/DownmixSw.h
@@ -0,0 +1,75 @@
+/*
+ * 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/effect/BnEffect.h>
+#include <fmq/AidlMessageQueue.h>
+#include <cstdlib>
+#include <memory>
+
+#include "effect-impl/EffectImpl.h"
+#include "effect-impl/EffectUUID.h"
+
+namespace aidl::android::hardware::audio::effect {
+
+class DownmixSwContext final : public EffectContext {
+  public:
+    DownmixSwContext(int statusDepth, const Parameter::Common& common)
+        : EffectContext(statusDepth, common) {
+        LOG(DEBUG) << __func__;
+    }
+
+    RetCode setDmType(Downmix::Type type) {
+        // TODO : Add implementation to apply new type
+        mType = type;
+        return RetCode::SUCCESS;
+    }
+    Downmix::Type getDmType() const { return mType; }
+
+  private:
+    Downmix::Type mType = Downmix::Type::STRIP;
+};
+
+class DownmixSw final : public EffectImpl {
+  public:
+    static const std::string kEffectName;
+    static const Downmix::Capability kCapability;
+    static const Descriptor kDescriptor;
+    DownmixSw() { LOG(DEBUG) << __func__; }
+    ~DownmixSw() {
+        cleanUp();
+        LOG(DEBUG) << __func__;
+    }
+
+    ndk::ScopedAStatus getDescriptor(Descriptor* _aidl_return) override;
+    ndk::ScopedAStatus setParameterSpecific(const Parameter::Specific& specific) override;
+    ndk::ScopedAStatus getParameterSpecific(const Parameter::Id& id,
+                                            Parameter::Specific* specific) override;
+
+    std::shared_ptr<EffectContext> createContext(const Parameter::Common& common) override;
+    std::shared_ptr<EffectContext> getContext() override;
+    RetCode releaseContext() override;
+
+    std::string getEffectName() override { return kEffectName; };
+    IEffect::Status effectProcessImpl(float* in, float* out, int sample) override;
+
+  private:
+    std::shared_ptr<DownmixSwContext> mContext;
+
+    ndk::ScopedAStatus getParameterDownmix(const Downmix::Tag& tag, Parameter::Specific* specific);
+};
+}  // namespace aidl::android::hardware::audio::effect