Adds default implementation for ultrasonics HAL

- Replicates logic from camera for default impl.

Bug: 148619310
Fixes: b/148608401
Test: Builds, VTS passes.

Change-Id: I5c1b4c615f98cb7405a9a233a7853daba09cc63d
diff --git a/automotive/evs/1.1/default/EvsUltrasonicsArray.h b/automotive/evs/1.1/default/EvsUltrasonicsArray.h
new file mode 100644
index 0000000..7a41012
--- /dev/null
+++ b/automotive/evs/1.1/default/EvsUltrasonicsArray.h
@@ -0,0 +1,134 @@
+/*
+ * Copyright 2020 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.
+ */
+
+#ifndef ANDROID_HARDWARE_AUTOMOTIVE_EVS_V1_1_EVSULTRASONICSARRAY_H
+#define ANDROID_HARDWARE_AUTOMOTIVE_EVS_V1_1_EVSULTRASONICSARRAY_H
+
+#include <thread>
+#include <utility>
+
+#include <android-base/macros.h>
+#include <android/hidl/allocator/1.0/IAllocator.h>
+#include <android/hidl/memory/1.0/IMemory.h>
+#include <utils/threads.h>
+
+#include <android/hardware/automotive/evs/1.1/IEvsUltrasonicsArray.h>
+#include <android/hardware/automotive/evs/1.1/IEvsUltrasonicsArrayStream.h>
+#include <android/hardware/automotive/evs/1.1/types.h>
+
+using ::android::hardware::hidl_memory;
+using ::android::hardware::automotive::evs::V1_0::EvsResult;
+using ::android::hardware::automotive::evs::V1_1::IEvsUltrasonicsArray;
+using ::android::hardware::automotive::evs::V1_1::IEvsUltrasonicsArrayStream;
+using ::android::hardware::automotive::evs::V1_1::UltrasonicsArrayDesc;
+using ::android::hardware::automotive::evs::V1_1::UltrasonicsDataFrameDesc;
+using ::android::hidl::allocator::V1_0::IAllocator;
+using ::android::hidl::memory::V1_0::IMemory;
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace evs {
+namespace V1_1 {
+namespace implementation {
+
+class EvsUltrasonicsArray : public IEvsUltrasonicsArray {
+  public:
+    // Methods from ::android::hardware::automotive::evs::V1_1::IEvsUltrasonicsArray follow.
+    Return<void> getUltrasonicArrayInfo(getUltrasonicArrayInfo_cb _get_info_cb) override;
+    Return<EvsResult> setMaxFramesInFlight(uint32_t bufferCount) override;
+    Return<void> doneWithDataFrame(const UltrasonicsDataFrameDesc& dataFrameDesc) override;
+    Return<EvsResult> startStream(const ::android::sp<IEvsUltrasonicsArrayStream>& stream) override;
+    Return<void> stopStream() override;
+
+    // Factory function to create a array.
+    static sp<EvsUltrasonicsArray> Create(const char* deviceName);
+
+    // Returns a ultrasonics array descriptor filled with sample data.
+    static UltrasonicsArrayDesc GetDummyArrayDesc(const char* id);
+
+    DISALLOW_COPY_AND_ASSIGN(EvsUltrasonicsArray);
+    virtual ~EvsUltrasonicsArray() override;
+    void forceShutdown();  // This gets called if another caller "steals" ownership
+
+  private:
+    // Structure holding the hidl memory struct and the interface to a shared memory.
+    struct SharedMemory {
+        hidl_memory hidlMemory;
+        sp<IMemory> pIMemory;
+
+        SharedMemory() : hidlMemory(hidl_memory()), pIMemory(nullptr){};
+
+        SharedMemory(hidl_memory hidlMem, sp<IMemory> pIMem)
+            : hidlMemory(hidlMem), pIMemory(pIMem) {}
+
+        bool IsValid() { return (pIMemory.get() != nullptr && hidlMemory.valid()); }
+
+        void clear() {
+            hidlMemory = hidl_memory();
+            pIMemory.clear();
+        }
+    };
+
+    // Struct for a data frame record.
+    struct DataFrameRecord {
+        SharedMemory sharedMemory;
+        bool inUse;
+        explicit DataFrameRecord(SharedMemory shMem) : sharedMemory(shMem), inUse(false){};
+    };
+
+    enum StreamStateValues {
+        STOPPED,
+        RUNNING,
+        STOPPING,
+        DEAD,
+    };
+
+    EvsUltrasonicsArray(const char* deviceName);
+
+    // These three functions are expected to be called while mAccessLock is held
+    bool setAvailableFrames_Locked(unsigned bufferCount);
+    unsigned increaseAvailableFrames_Locked(unsigned numToAdd);
+    unsigned decreaseAvailableFrames_Locked(unsigned numToRemove);
+
+    void generateDataFrames();
+
+    SharedMemory allocateAndMapSharedMemory();
+
+    UltrasonicsArrayDesc mArrayDesc = {};  // The properties of this ultrasonic array.
+
+    std::thread mCaptureThread;  // The thread we'll use to synthesize frames
+
+    sp<IEvsUltrasonicsArrayStream> mStream = nullptr;  // The callback used to deliver each frame
+
+    sp<IAllocator> mShmemAllocator = nullptr;  // Shared memory allocator.
+
+    std::mutex mAccessLock;
+    std::vector<DataFrameRecord> mDataFrames GUARDED_BY(mAccessLock);  // Shared memory buffers.
+    unsigned mFramesAllowed GUARDED_BY(mAccessLock);  // How many buffers are we currently using.
+    unsigned mFramesInUse GUARDED_BY(mAccessLock);  // How many buffers are currently outstanding.
+
+    StreamStateValues mStreamState GUARDED_BY(mAccessLock);
+};
+
+}  // namespace implementation
+}  // namespace V1_1
+}  // namespace evs
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_AUTOMOTIVE_EVS_V1_1_EVSULTRASONICSARRAY_H