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.cpp b/automotive/evs/1.1/default/EvsUltrasonicsArray.cpp
new file mode 100644
index 0000000..bc69aa4
--- /dev/null
+++ b/automotive/evs/1.1/default/EvsUltrasonicsArray.cpp
@@ -0,0 +1,551 @@
+/*
+ * 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.
+ */
+
+#include "EvsUltrasonicsArray.h"
+
+#include <android-base/logging.h>
+#include <hidlmemory/mapping.h>
+#include <log/log.h>
+#include <time.h>
+#include <utils/SystemClock.h>
+#include <utils/Timers.h>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace evs {
+namespace V1_1 {
+namespace implementation {
+
+// Arbitrary limit on number of data frames allowed to be allocated
+// Safeguards against unreasonable resource consumption and provides a testable limit
+const unsigned int kMaximumDataFramesInFlight = 100;
+
+const uint32_t kMaxReadingsPerSensor = 5;
+const uint32_t kMaxReceiversCount = 3;
+
+const unsigned int kSharedMemoryMaxSize =
+        kMaxReadingsPerSensor * kMaxReceiversCount * 2 * sizeof(float);
+
+// Target frame rate in frames per second.
+const int kTargetFrameRate = 10;
+
+namespace {
+
+void fillDummyArrayDesc(UltrasonicsArrayDesc& arrayDesc) {
+    arrayDesc.maxReadingsPerSensorCount = kMaxReadingsPerSensor;
+    arrayDesc.maxReceiversCount = kMaxReceiversCount;
+
+    const int kSensorCount = 3;
+    const float kMaxRange = 4000;                // 4 metres.
+    const float kAngleOfMeasurement = 0.261799;  // 15 degrees.
+
+    std::vector<UltrasonicSensor> sensors(kSensorCount);
+
+    // Sensor pointing forward on left side of front bumper.
+    sensors[0].maxRange = kMaxRange;
+    sensors[0].angleOfMeasurement = kAngleOfMeasurement;
+    sensors[0].pose = {{1, 0, 0, 0}, {-1000, 2000, 200}};
+
+    // Sensor pointing forward on center of front bumper.
+    sensors[1].maxRange = kMaxRange;
+    sensors[1].angleOfMeasurement = kAngleOfMeasurement;
+    sensors[1].pose = {{1, 0, 0, 0}, {0, 2000, 200}};
+
+    // Sensor pointing forward on right side of front bumper.
+    sensors[2].maxRange = kMaxRange;
+    sensors[2].angleOfMeasurement = kAngleOfMeasurement;
+    sensors[2].pose = {{1, 0, 0, 0}, {1000, 2000, 200}};
+
+    arrayDesc.sensors = sensors;
+}
+
+// Struct used by SerializeWaveformData().
+struct WaveformData {
+    uint8_t receiverId;
+    std::vector<std::pair<float, float>> readings;
+};
+
+// Serializes data provided in waveformDataList to a shared memory data pointer.
+// TODO(b/149950362): Add a common library for serialiazing and deserializing waveform data.
+void SerializeWaveformData(const std::vector<WaveformData>& waveformDataList, uint8_t* pData) {
+    for (auto& waveformData : waveformDataList) {
+        // Set Id
+        memcpy(pData, &waveformData.receiverId, sizeof(uint8_t));
+        pData += sizeof(uint8_t);
+
+        for (auto& reading : waveformData.readings) {
+            // Set the time of flight.
+            memcpy(pData, &reading.first, sizeof(float));
+            pData += sizeof(float);
+
+            // Set the resonance.
+            memcpy(pData, &reading.second, sizeof(float));
+            pData += sizeof(float);
+        }
+    }
+}
+
+// Fills dataFrameDesc with dummy data.
+bool fillDummyDataFrame(UltrasonicsDataFrameDesc& dataFrameDesc, sp<IMemory> pIMemory) {
+    dataFrameDesc.timestampNs = elapsedRealtimeNano();
+
+    const std::vector<uint8_t> transmittersIdList = {0};
+    dataFrameDesc.transmittersIdList = transmittersIdList;
+
+    const std::vector<uint8_t> recvIdList = {0, 1, 2};
+    dataFrameDesc.receiversIdList = recvIdList;
+
+    const std::vector<uint32_t> receiversReadingsCountList = {2, 2, 4};
+    dataFrameDesc.receiversReadingsCountList = receiversReadingsCountList;
+
+    const std::vector<WaveformData> waveformDataList = {
+            {recvIdList[0], { {1000, 0.1f}, {2000, 0.8f} }},
+            {recvIdList[1], { {1000, 0.1f}, {2000, 1.0f} }},
+            {recvIdList[2], { {1000, 0.1f}, {2000, 0.2f}, {4000, 0.2f}, {5000, 0.1f} }}
+    };
+
+    if (pIMemory.get() == nullptr) {
+        return false;
+    }
+
+    uint8_t* pData = (uint8_t*)((void*)pIMemory->getPointer());
+
+    pIMemory->update();
+    SerializeWaveformData(waveformDataList, pData);
+    pIMemory->commit();
+
+    return true;
+}
+
+}  // namespace
+
+EvsUltrasonicsArray::EvsUltrasonicsArray(const char* deviceName)
+    : mFramesAllowed(0), mFramesInUse(0), mStreamState(STOPPED) {
+    LOG(DEBUG) << "EvsUltrasonicsArray instantiated";
+
+    // Set up dummy data for description.
+    mArrayDesc.ultrasonicsArrayId = deviceName;
+    fillDummyArrayDesc(mArrayDesc);
+
+    // Assign allocator.
+    mShmemAllocator = IAllocator::getService("ashmem");
+    if (mShmemAllocator.get() == nullptr) {
+        LOG(ERROR) << "SurroundViewHidlTest getService ashmem failed";
+    }
+}
+
+sp<EvsUltrasonicsArray> EvsUltrasonicsArray::Create(const char* deviceName) {
+    return sp<EvsUltrasonicsArray>(new EvsUltrasonicsArray(deviceName));
+}
+
+EvsUltrasonicsArray::~EvsUltrasonicsArray() {
+    LOG(DEBUG) << "EvsUltrasonicsArray being destroyed";
+    forceShutdown();
+}
+
+// This gets called if another caller "steals" ownership of the ultrasonic array.
+void EvsUltrasonicsArray::forceShutdown() {
+    LOG(DEBUG) << "EvsUltrasonicsArray forceShutdown";
+
+    // Make sure our output stream is cleaned up
+    // (It really should be already)
+    stopStream();
+
+    // Claim the lock while we work on internal state
+    std::lock_guard<std::mutex> lock(mAccessLock);
+
+    // Drop all the data frames we've been using
+    for (auto&& dataFrame : mDataFrames) {
+        if (dataFrame.inUse) {
+            LOG(ERROR) << "Error - releasing data frame despite remote ownership";
+        }
+        dataFrame.sharedMemory.clear();
+    }
+    mDataFrames.clear();
+
+    // Put this object into an unrecoverable error state since somebody else
+    // is going to own the underlying ultrasonic array now
+    mStreamState = DEAD;
+}
+
+UltrasonicsArrayDesc EvsUltrasonicsArray::GetDummyArrayDesc(const char* deviceName) {
+    UltrasonicsArrayDesc ultrasonicsArrayDesc;
+    ultrasonicsArrayDesc.ultrasonicsArrayId = deviceName;
+    fillDummyArrayDesc(ultrasonicsArrayDesc);
+    return ultrasonicsArrayDesc;
+}
+
+Return<void> EvsUltrasonicsArray::getUltrasonicArrayInfo(getUltrasonicArrayInfo_cb _get_info_cb) {
+    LOG(DEBUG) << "EvsUltrasonicsArray getUltrasonicsArrayInfo";
+
+    // Return the description for the get info callback.
+    _get_info_cb(mArrayDesc);
+
+    return Void();
+}
+
+Return<EvsResult> EvsUltrasonicsArray::setMaxFramesInFlight(uint32_t bufferCount) {
+    LOG(DEBUG) << "EvsUltrasonicsArray setMaxFramesInFlight";
+
+    // Lock mutex for performing changes to available frames.
+    std::lock_guard<std::mutex> lock(mAccessLock);
+
+    // We cannot function without at least one buffer to send data.
+    if (bufferCount < 1) {
+        LOG(ERROR) << "Ignoring setMaxFramesInFlight with less than one buffer requested";
+        return EvsResult::INVALID_ARG;
+    }
+
+    // Update our internal state of buffer count.
+    if (setAvailableFrames_Locked(bufferCount)) {
+        return EvsResult::OK;
+    } else {
+        return EvsResult::BUFFER_NOT_AVAILABLE;
+    }
+
+    return EvsResult::OK;
+}
+
+Return<void> EvsUltrasonicsArray::doneWithDataFrame(const UltrasonicsDataFrameDesc& dataFrameDesc) {
+    LOG(DEBUG) << "EvsUltrasonicsArray doneWithFrame";
+
+    std::lock_guard<std::mutex> lock(mAccessLock);
+
+    if (dataFrameDesc.dataFrameId >= mDataFrames.size()) {
+        LOG(ERROR) << "ignoring doneWithFrame called with invalid dataFrameId "
+                   << dataFrameDesc.dataFrameId << "(max is " << mDataFrames.size() - 1 << ")";
+        return Void();
+    }
+
+    if (!mDataFrames[dataFrameDesc.dataFrameId].inUse) {
+        LOG(ERROR) << "ignoring doneWithFrame called on frame " << dataFrameDesc.dataFrameId
+                   << "which is already free";
+        return Void();
+    }
+
+    // Mark the frame as available
+    mDataFrames[dataFrameDesc.dataFrameId].inUse = false;
+    mFramesInUse--;
+
+    // If this frame's index is high in the array, try to move it down
+    // to improve locality after mFramesAllowed has been reduced.
+    if (dataFrameDesc.dataFrameId >= mFramesAllowed) {
+        // Find an empty slot lower in the array (which should always exist in this case)
+        for (auto&& dataFrame : mDataFrames) {
+            if (!dataFrame.sharedMemory.IsValid()) {
+                dataFrame.sharedMemory = mDataFrames[dataFrameDesc.dataFrameId].sharedMemory;
+                mDataFrames[dataFrameDesc.dataFrameId].sharedMemory.clear();
+                return Void();
+            }
+        }
+    }
+
+    return Void();
+}
+
+Return<EvsResult> EvsUltrasonicsArray::startStream(
+        const ::android::sp<IEvsUltrasonicsArrayStream>& stream) {
+    LOG(DEBUG) << "EvsUltrasonicsArray startStream";
+
+    std::lock_guard<std::mutex> lock(mAccessLock);
+
+    if (mStreamState != STOPPED) {
+        LOG(ERROR) << "ignoring startStream call when a stream is already running.";
+        return EvsResult::STREAM_ALREADY_RUNNING;
+    }
+
+    // If the client never indicated otherwise, configure ourselves for a single streaming buffer
+    if (mFramesAllowed < 1) {
+        if (!setAvailableFrames_Locked(1)) {
+            LOG(ERROR)
+                    << "Failed to start stream because we couldn't get shared memory data buffer";
+            return EvsResult::BUFFER_NOT_AVAILABLE;
+        }
+    }
+
+    // Record the user's callback for use when we have a frame ready
+    mStream = stream;
+
+    // Start the frame generation thread
+    mStreamState = RUNNING;
+    mCaptureThread = std::thread([this]() { generateDataFrames(); });
+
+    return EvsResult::OK;
+}
+
+Return<void> EvsUltrasonicsArray::stopStream() {
+    LOG(DEBUG) << "EvsUltrasonicsArray stopStream";
+
+    bool streamStateStopping = false;
+    {
+        std::lock_guard<std::mutex> lock(mAccessLock);
+        if (mStreamState == RUNNING) {
+            // Tell the GenerateFrames loop we want it to stop
+            mStreamState = STOPPING;
+            streamStateStopping = true;
+        }
+    }
+
+    if (streamStateStopping) {
+        // Block outside the mutex until the "stop" flag has been acknowledged
+        // We won't send any more frames, but the client might still get some already in flight
+        LOG(DEBUG) << "Waiting for stream thread to end...";
+        mCaptureThread.join();
+    }
+
+    {
+        std::lock_guard<std::mutex> lock(mAccessLock);
+        mStreamState = STOPPED;
+        mStream = nullptr;
+        LOG(DEBUG) << "Stream marked STOPPED.";
+    }
+
+    return Void();
+}
+
+bool EvsUltrasonicsArray::setAvailableFrames_Locked(unsigned bufferCount) {
+    if (bufferCount < 1) {
+        LOG(ERROR) << "Ignoring request to set buffer count to zero";
+        return false;
+    }
+    if (bufferCount > kMaximumDataFramesInFlight) {
+        LOG(ERROR) << "Rejecting buffer request in excess of internal limit";
+        return false;
+    }
+
+    // Is an increase required?
+    if (mFramesAllowed < bufferCount) {
+        // An increase is required
+        unsigned needed = bufferCount - mFramesAllowed;
+        LOG(INFO) << "Number of data frame buffers to add: " << needed;
+
+        unsigned added = increaseAvailableFrames_Locked(needed);
+        if (added != needed) {
+            // If we didn't add all the frames we needed, then roll back to the previous state
+            LOG(ERROR) << "Rolling back to previous frame queue size";
+            decreaseAvailableFrames_Locked(added);
+            return false;
+        }
+    } else if (mFramesAllowed > bufferCount) {
+        // A decrease is required
+        unsigned framesToRelease = mFramesAllowed - bufferCount;
+        LOG(INFO) << "Number of data frame buffers to reduce: " << framesToRelease;
+
+        unsigned released = decreaseAvailableFrames_Locked(framesToRelease);
+        if (released != framesToRelease) {
+            // This shouldn't happen with a properly behaving client because the client
+            // should only make this call after returning sufficient outstanding buffers
+            // to allow a clean resize.
+            LOG(ERROR) << "Buffer queue shrink failed -- too many buffers currently in use?";
+        }
+    }
+
+    return true;
+}
+
+EvsUltrasonicsArray::SharedMemory EvsUltrasonicsArray::allocateAndMapSharedMemory() {
+    SharedMemory sharedMemory;
+
+    // Check shared memory allocator is valid.
+    if (mShmemAllocator.get() == nullptr) {
+        LOG(ERROR) << "Shared memory allocator not initialized.";
+        return SharedMemory();
+    }
+
+    // Allocate memory.
+    bool allocateSuccess = false;
+    Return<void> result = mShmemAllocator->allocate(kSharedMemoryMaxSize,
+                                                    [&](bool success, const hidl_memory& hidlMem) {
+                                                        if (!success) {
+                                                            return;
+                                                        }
+                                                        allocateSuccess = success;
+                                                        sharedMemory.hidlMemory = hidlMem;
+                                                    });
+
+    // Check result of allocated memory.
+    if (!result.isOk() || !allocateSuccess) {
+        LOG(ERROR) << "Shared memory allocation failed.";
+        return SharedMemory();
+    }
+
+    // Map shared memory.
+    sharedMemory.pIMemory = mapMemory(sharedMemory.hidlMemory);
+    if (sharedMemory.pIMemory.get() == nullptr) {
+        LOG(ERROR) << "Shared memory mapping failed.";
+        return SharedMemory();
+    }
+
+    // Return success.
+    return sharedMemory;
+}
+
+unsigned EvsUltrasonicsArray::increaseAvailableFrames_Locked(unsigned numToAdd) {
+    unsigned added = 0;
+
+    while (added < numToAdd) {
+        SharedMemory sharedMemory = allocateAndMapSharedMemory();
+
+        // If allocate and map fails, break.
+        if (!sharedMemory.IsValid()) {
+            break;
+        }
+
+        // Find a place to store the new buffer
+        bool stored = false;
+        for (auto&& dataFrame : mDataFrames) {
+            if (!dataFrame.sharedMemory.IsValid()) {
+                // Use this existing entry
+                dataFrame.sharedMemory = sharedMemory;
+                dataFrame.inUse = false;
+                stored = true;
+                break;
+            }
+        }
+
+        if (!stored) {
+            // Add a BufferRecord wrapping this handle to our set of available buffers
+            mDataFrames.emplace_back(sharedMemory);
+        }
+
+        mFramesAllowed++;
+        added++;
+    }
+
+    return added;
+}
+
+unsigned EvsUltrasonicsArray::decreaseAvailableFrames_Locked(unsigned numToRemove) {
+    unsigned removed = 0;
+
+    for (auto&& dataFrame : mDataFrames) {
+        // Is this record not in use, but holding a buffer that we can free?
+        if (!dataFrame.inUse && dataFrame.sharedMemory.IsValid()) {
+            // Release buffer and update the record so we can recognize it as "empty"
+            dataFrame.sharedMemory.clear();
+
+            mFramesAllowed--;
+            removed++;
+
+            if (removed == numToRemove) {
+                break;
+            }
+        }
+    }
+
+    return removed;
+}
+
+// This is the asynchronous data frame generation thread that runs in parallel with the
+// main serving thread. There is one for each active ultrasonic array instance.
+void EvsUltrasonicsArray::generateDataFrames() {
+    LOG(DEBUG) << "Data frame generation loop started";
+
+    unsigned idx = 0;
+
+    while (true) {
+        bool timeForFrame = false;
+
+        nsecs_t startTime = elapsedRealtimeNano();
+
+        // Lock scope for updating shared state
+        {
+            std::lock_guard<std::mutex> lock(mAccessLock);
+
+            if (mStreamState != RUNNING) {
+                // Break out of our main thread loop
+                break;
+            }
+
+            // Are we allowed to issue another buffer?
+            if (mFramesInUse >= mFramesAllowed) {
+                // Can't do anything right now -- skip this frame
+                LOG(WARNING) << "Skipped a frame because too many are in flight";
+            } else {
+                // Identify an available buffer to fill
+                for (idx = 0; idx < mDataFrames.size(); idx++) {
+                    if (!mDataFrames[idx].inUse && mDataFrames[idx].sharedMemory.IsValid()) {
+                        // Found an available record, so stop looking
+                        break;
+                    }
+                }
+                if (idx >= mDataFrames.size()) {
+                    // This shouldn't happen since we already checked mFramesInUse vs mFramesAllowed
+                    LOG(ERROR) << "Failed to find an available buffer slot";
+                } else {
+                    // We're going to make the frame busy
+                    mDataFrames[idx].inUse = true;
+                    mFramesInUse++;
+                    timeForFrame = true;
+                }
+            }
+        }
+
+        if (timeForFrame) {
+            // Assemble the buffer description we'll transmit below
+            UltrasonicsDataFrameDesc dummyDataFrameDesc;
+            dummyDataFrameDesc.dataFrameId = idx;
+            dummyDataFrameDesc.waveformsData = mDataFrames[idx].sharedMemory.hidlMemory;
+
+            // Fill dummy waveform data.
+            fillDummyDataFrame(dummyDataFrameDesc, mDataFrames[idx].sharedMemory.pIMemory);
+
+            // Issue the (asynchronous) callback to the client -- can't be holding the lock
+            auto result = mStream->deliverDataFrame(dummyDataFrameDesc);
+            if (result.isOk()) {
+                LOG(DEBUG) << "Delivered data frame id: " << dummyDataFrameDesc.dataFrameId;
+            } else {
+                // This can happen if the client dies and is likely unrecoverable.
+                // To avoid consuming resources generating failing calls, we stop sending
+                // frames.  Note, however, that the stream remains in the "STREAMING" state
+                // until cleaned up on the main thread.
+                LOG(ERROR) << "Frame delivery call failed in the transport layer.";
+
+                // Since we didn't actually deliver it, mark the frame as available
+                std::lock_guard<std::mutex> lock(mAccessLock);
+                mDataFrames[idx].inUse = false;
+                mFramesInUse--;
+
+                break;
+            }
+        }
+
+        // Sleep to generate frames at kTargetFrameRate.
+        static const nsecs_t kTargetFrameTimeUs = 1000 * 1000 / kTargetFrameRate;
+        const nsecs_t now = elapsedRealtimeNano();
+        const nsecs_t workTimeUs = (now - startTime) / 1000;
+        const nsecs_t sleepDurationUs = kTargetFrameTimeUs - workTimeUs;
+        if (sleepDurationUs > 0) {
+            usleep(sleepDurationUs);
+        }
+    }
+
+    // If we've been asked to stop, send an event to signal the actual end of stream
+    EvsEventDesc event;
+    event.aType = EvsEventType::STREAM_STOPPED;
+    auto result = mStream->notify(event);
+    if (!result.isOk()) {
+        LOG(ERROR) << "Error delivering end of stream marker";
+    }
+}
+
+}  // namespace implementation
+}  // namespace V1_1
+}  // namespace evs
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android