Style fix: renaming and include guards.

Fixes file name style and include guard style, before
even more and more files get added.

BUG: 30224839
Change-Id: Ie5ebcf14672c7e9d3faae86b88d4f62b516ae00d
TEST: test program that takes a picture still works.
diff --git a/modules/camera/3_4/v4l2_camera.cpp b/modules/camera/3_4/v4l2_camera.cpp
new file mode 100644
index 0000000..81cbf64
--- /dev/null
+++ b/modules/camera/3_4/v4l2_camera.cpp
@@ -0,0 +1,1546 @@
+/*
+ * Copyright 2016 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 "v4l2_camera.h"
+
+#include <fcntl.h>
+#include <linux/videodev2.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <cstdlib>
+
+#include <camera/CameraMetadata.h>
+#include <hardware/camera3.h>
+#include <nativehelper/ScopedFd.h>
+
+#include "common.h"
+#include "stream_format.h"
+#include "v4l2_gralloc.h"
+
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof(*(a)))
+
+namespace v4l2_camera_hal {
+
+// Helper function for managing metadata.
+static std::vector<int32_t> getMetadataKeys(
+    const camera_metadata_t* metadata) {
+  std::vector<int32_t> keys;
+  size_t num_entries = get_camera_metadata_entry_count(metadata);
+  for (size_t i = 0; i < num_entries; ++i) {
+    camera_metadata_ro_entry_t entry;
+    get_camera_metadata_ro_entry(metadata, i, &entry);
+    keys.push_back(entry.tag);
+  }
+  return keys;
+}
+
+V4L2Camera* V4L2Camera::NewV4L2Camera(int id, const std::string path) {
+  HAL_LOG_ENTER();
+
+  std::unique_ptr<V4L2Wrapper> v4l2_wrapper(V4L2Wrapper::NewV4L2Wrapper(path));
+  if (!v4l2_wrapper) {
+    HAL_LOGE("Failed to initialize V4L2 wrapper.");
+    return nullptr;
+  }
+
+  return new V4L2Camera(id, std::move(v4l2_wrapper));
+}
+
+V4L2Camera::V4L2Camera(int id, std::unique_ptr<V4L2Wrapper> v4l2_wrapper)
+    : default_camera_hal::Camera(id),
+      mV4L2Device(std::move(v4l2_wrapper)),
+      mTemplatesInitialized(false),
+      mCharacteristicsInitialized(false) {
+  HAL_LOG_ENTER();
+}
+
+V4L2Camera::~V4L2Camera() {
+  HAL_LOG_ENTER();
+}
+
+int V4L2Camera::connect() {
+  HAL_LOG_ENTER();
+
+  int res = mV4L2Device->Connect();
+  if (res) {
+    HAL_LOGE("Failed to connect to device.");
+    return res;
+  }
+
+  // TODO(b/29185945): confirm this is a supported device.
+  // This is checked by the HAL, but the device at mDevicePath may
+  // not be the same one that was there when the HAL was loaded.
+  // (Alternatively, better hotplugging support may make this unecessary
+  // by disabling cameras that get disconnected and checking newly connected
+  // cameras, so connect() is never called on an unsupported camera)
+
+  // TODO(b/29158098): Inform service of any flashes that are no longer available
+  // because this camera is in use.
+  return 0;
+}
+
+void V4L2Camera::disconnect() {
+  HAL_LOG_ENTER();
+
+  mV4L2Device->Disconnect();
+
+  // TODO(b/29158098): Inform service of any flashes that are available again
+  // because this camera is no longer in use.
+}
+
+int V4L2Camera::initStaticInfo(camera_metadata_t** out) {
+  HAL_LOG_ENTER();
+
+  android::status_t res;
+  // Device characteristics need to be queried prior
+  // to static info setup.
+  if (!mCharacteristicsInitialized) {
+    res = initCharacteristics();
+    if (res) {
+      return res;
+    }
+  }
+
+  android::CameraMetadata info;
+
+  // Static metadata characteristics from /system/media/camera/docs/docs.html.
+
+  /* android.colorCorrection. */
+
+  // No easy way to turn chromatic aberration correction OFF in v4l2,
+  // though this may be supportable via a collection of other user controls.
+  uint8_t avail_aberration_modes[] = {
+    ANDROID_COLOR_CORRECTION_ABERRATION_MODE_FAST,
+    ANDROID_COLOR_CORRECTION_ABERRATION_MODE_HIGH_QUALITY};
+  res = info.update(ANDROID_COLOR_CORRECTION_AVAILABLE_ABERRATION_MODES,
+                    avail_aberration_modes, ARRAY_SIZE(avail_aberration_modes));
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.control. */
+
+  /*   3As */
+
+  res = info.update(ANDROID_CONTROL_AE_AVAILABLE_ANTIBANDING_MODES,
+                    mAeAntibandingModes.data(), mAeAntibandingModes.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_CONTROL_AE_AVAILABLE_MODES,
+                    mAeModes.data(), mAeModes.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  // Flatten mFpsRanges.
+  res = info.update(ANDROID_CONTROL_AE_AVAILABLE_TARGET_FPS_RANGES,
+                    mFpsRanges.data(), mFpsRanges.total_num_elements());
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_CONTROL_AE_COMPENSATION_RANGE,
+                    mAeCompensationRange.data(), mAeCompensationRange.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_CONTROL_AE_COMPENSATION_STEP,
+                    &mAeCompensationStep, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_CONTROL_AF_AVAILABLE_MODES,
+                    mAfModes.data(), mAfModes.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_CONTROL_AWB_AVAILABLE_MODES,
+                    mAwbModes.data(), mAwbModes.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  // Couldn't find any V4L2 support for regions, though maybe it's out there.
+  int32_t max_regions[] = {/*AE*/ 0,/*AWB*/ 0,/*AF*/ 0};
+  res = info.update(ANDROID_CONTROL_MAX_REGIONS,
+                    max_regions, ARRAY_SIZE(max_regions));
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_CONTROL_AE_LOCK_AVAILABLE,
+                    &mAeLockAvailable, 1);
+  if (res != android::OK) {
+    return res;
+  }
+  res = info.update(ANDROID_CONTROL_AWB_LOCK_AVAILABLE,
+                    &mAwbLockAvailable, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /*   Scene modes. */
+
+  res = info.update(ANDROID_CONTROL_AVAILABLE_SCENE_MODES,
+                    mSceneModes.data(), mSceneModes.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  // A 3-tuple of AE, AWB, AF overrides for each scene mode.
+  // Ignored for DISABLED, FACE_PRIORITY and FACE_PRIORITY_LOW_LIGHT.
+  uint8_t scene_mode_overrides[] = {
+    /*SCENE_MODE_DISABLED*/ /*AE*/0, /*AW*/0, /*AF*/0};
+  res = info.update(ANDROID_CONTROL_SCENE_MODE_OVERRIDES,
+                    scene_mode_overrides, ARRAY_SIZE(scene_mode_overrides));
+  if (res != android::OK) {
+    return res;
+  }
+
+  /*   Top level 3A/Scenes switch. */
+
+  res = info.update(ANDROID_CONTROL_AVAILABLE_MODES,
+                    mControlModes.data(), mControlModes.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  /*   Other android.control configuration. */
+
+  res = info.update(ANDROID_CONTROL_AVAILABLE_VIDEO_STABILIZATION_MODES,
+                    mVideoStabilizationModes.data(),
+                    mVideoStabilizationModes.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_CONTROL_AVAILABLE_EFFECTS,
+                    mEffects.data(), mEffects.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  // AVAILABLE_HIGH_SPEED_VIDEO_CONFIGURATIONS only necessary
+  // for devices supporting CONSTRAINED_HIGH_SPEED_VIDEO,
+  // which this HAL doesn't support.
+
+  // POST_RAW_SENSITIVITY_BOOST_RANGE only necessary
+  // for devices supporting RAW format outputs.
+
+  /* android.edge. */
+
+  // Not sure if V4L2 does or doesn't do this, but HAL documentation says
+  // all devices must support FAST, and FAST can be equivalent to OFF, so
+  // either way it's fine to list.
+  uint8_t avail_edge_modes[] = {
+    ANDROID_EDGE_MODE_FAST};
+  res = info.update(ANDROID_EDGE_AVAILABLE_EDGE_MODES,
+                    avail_edge_modes, ARRAY_SIZE(avail_edge_modes));
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.flash. */
+
+  res = info.update(ANDROID_FLASH_INFO_AVAILABLE,
+                    &mFlashAvailable, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // info.chargeDuration, color.Temperature, maxEnergy marked FUTURE.
+
+  /* android.hotPixel. */
+
+  // No known V4L2 hot pixel correction. But it might be happening,
+  // so we report FAST/HIGH_QUALITY.
+  uint8_t avail_hot_pixel_modes[] = {
+    ANDROID_HOT_PIXEL_MODE_FAST,
+    ANDROID_HOT_PIXEL_MODE_HIGH_QUALITY};
+  res = info.update(ANDROID_HOT_PIXEL_AVAILABLE_HOT_PIXEL_MODES,
+                    avail_hot_pixel_modes, ARRAY_SIZE(avail_hot_pixel_modes));
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.jpeg. */
+
+  // For now, no thumbnails available (only [0,0], the "no thumbnail" size).
+  // TODO(b/29580107): Could end up with a mismatch between request & result,
+  // since V4L2 doesn't actually allow for thumbnail size control.
+  int32_t thumbnail_sizes[] = {
+    0, 0};
+  res = info.update(ANDROID_JPEG_AVAILABLE_THUMBNAIL_SIZES,
+                    thumbnail_sizes, ARRAY_SIZE(thumbnail_sizes));
+  if (res != android::OK) {
+    return res;
+  }
+
+  // V4L2 can query this with VIDIOC_TRY_FMT (or VIDIOC_S_FMT if TRY
+  // isn't supported), reading the fmt.pix.sizeimage for the largest
+  // jpeg size. For now use a constant (defined in V4L2Gralloc.h).
+  int32_t max_jpeg_size = V4L2_MAX_JPEG_SIZE;
+  res = info.update(ANDROID_JPEG_MAX_SIZE,
+                    &max_jpeg_size, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.lens. */
+
+  /*   Misc. lens control. */
+
+  res = info.update(ANDROID_LENS_INFO_AVAILABLE_APERTURES,
+                    &mAperture, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_LENS_INFO_AVAILABLE_FILTER_DENSITIES,
+                    &mFilterDensity, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_LENS_INFO_AVAILABLE_OPTICAL_STABILIZATION,
+                    mOpticalStabilizationModes.data(),
+                    mOpticalStabilizationModes.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  // No known V4L2 shading map info.
+  int32_t shading_map_size[] = {1, 1};
+  res = info.update(ANDROID_LENS_INFO_SHADING_MAP_SIZE,
+                    shading_map_size, ARRAY_SIZE(shading_map_size));
+  if (res != android::OK) {
+    return res;
+  }
+
+  // All V4L2 devices are considered to be external facing.
+  uint8_t facing = ANDROID_LENS_FACING_EXTERNAL;
+  res = info.update(ANDROID_LENS_FACING, &facing, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /*   Zoom/Focus. */
+
+  // No way to actually get the focal length in V4L2, but it's a required key,
+  // so we just fake it.
+  res = info.update(ANDROID_LENS_INFO_AVAILABLE_FOCAL_LENGTHS,
+                    &mFocalLength, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // V4L2 focal units do not correspond to a particular physical unit.
+  uint8_t focus_calibration =
+      ANDROID_LENS_INFO_FOCUS_DISTANCE_CALIBRATION_UNCALIBRATED;
+  res = info.update(ANDROID_LENS_INFO_FOCUS_DISTANCE_CALIBRATION,
+                    &focus_calibration, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // info.hyperfocalDistance not required for UNCALIBRATED.
+
+  res = info.update(ANDROID_LENS_INFO_MINIMUM_FOCUS_DISTANCE,
+                    &mFocusDistance, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /*   Depth. */
+
+  // DEPTH capability not supported by this HAL. Not implemented:
+  // poseRotation
+  // poseTranslation
+  // intrinsicCalibration
+  // radialDistortion
+
+  /* anroid.noise. */
+
+  // Unable to control noise reduction in V4L2 devices,
+  // but FAST is allowed to be the same as OFF.
+  uint8_t avail_noise_reduction_modes[] = {ANDROID_NOISE_REDUCTION_MODE_FAST};
+  res = info.update(ANDROID_NOISE_REDUCTION_AVAILABLE_NOISE_REDUCTION_MODES,
+                    avail_noise_reduction_modes,
+                    ARRAY_SIZE(avail_noise_reduction_modes));
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.request. */
+
+  int32_t max_num_output_streams[] = {mMaxRawOutputStreams,
+                                      mMaxNonStallingOutputStreams,
+                                      mMaxStallingOutputStreams};
+  res = info.update(ANDROID_REQUEST_MAX_NUM_OUTPUT_STREAMS,
+                    max_num_output_streams, ARRAY_SIZE(max_num_output_streams));
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_REQUEST_MAX_NUM_INPUT_STREAMS,
+                    &mMaxInputStreams, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // No way to know for V4L2, so fake with max allowable latency.
+  // Doesn't mean much without per-frame controls.
+  uint8_t pipeline_max_depth = 4;
+  res = info.update(ANDROID_REQUEST_PIPELINE_MAX_DEPTH,
+                    &pipeline_max_depth, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // Partial results not supported; partialResultCount defaults to 1.
+
+  // Available capabilities & keys queried at very end of this method.
+
+  /* android.scaler. */
+
+  /*   Cropping. */
+
+  res = info.update(ANDROID_SCALER_AVAILABLE_MAX_DIGITAL_ZOOM,
+                    &mMaxZoom, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_SCALER_CROPPING_TYPE, &mCropType, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /*   Streams. */
+
+  // availableInputOutputFormatsMap only required for reprocessing capability.
+
+  // Flatten mStreamConfigs.
+  res = info.update(ANDROID_SCALER_AVAILABLE_STREAM_CONFIGURATIONS,
+                    mStreamConfigs.data(),
+                    mStreamConfigs.total_num_elements());
+  if (res != android::OK) {
+    return res;
+  }
+
+  // Flatten mMinFrameDurations.
+  res = info.update(ANDROID_SCALER_AVAILABLE_MIN_FRAME_DURATIONS,
+                    mMinFrameDurations.data(),
+                    mMinFrameDurations.total_num_elements());
+  if (res != android::OK) {
+    return res;
+  }
+
+  // Flatten mStallDurations.
+  res = info.update(ANDROID_SCALER_AVAILABLE_STALL_DURATIONS,
+                    mStallDurations.data(),
+                    mStallDurations.total_num_elements());
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.sensor. */
+
+  /*   Sizes. */
+
+  res = info.update(ANDROID_SENSOR_INFO_PIXEL_ARRAY_SIZE,
+                    mPixelArraySize.data(), mPixelArraySize.size());
+  if (res != android::OK) {
+    return res;
+  }
+  // No V4L2 way to differentiate active vs. inactive parts of the rectangle.
+  res = info.update(ANDROID_SENSOR_INFO_ACTIVE_ARRAY_SIZE,
+                    mPixelArraySize.data(), mPixelArraySize.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  res = info.update(ANDROID_SENSOR_INFO_PHYSICAL_SIZE,
+                    mPhysicalSize.data(), mPhysicalSize.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  /*   Misc sensor information. */
+
+  res = info.update(ANDROID_SENSOR_INFO_MAX_FRAME_DURATION,
+                    &mMaxFrameDuration, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // HAL uses BOOTTIME timestamps.
+  // TODO(b/29457051): make sure timestamps are consistent throughout the HAL.
+  uint8_t timestamp_source = ANDROID_SENSOR_INFO_TIMESTAMP_SOURCE_UNKNOWN;
+  res = info.update(ANDROID_SENSOR_INFO_TIMESTAMP_SOURCE,
+                    &timestamp_source, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // As in initDeviceInfo, no way to actually get orientation.
+  res = info.update(ANDROID_SENSOR_ORIENTATION, &mOrientation, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // availableTestPatternModes just defaults to OFF, which is fine.
+
+  // info.exposureTimeRange, info.sensitivityRange:
+  // exposure/sensitivity manual control not supported.
+  // Could query V4L2_CID_ISO_SENSITIVITY to support sensitivity if desired.
+
+  // info.whiteLevel, info.lensShadingApplied,
+  // info.preCorrectionPixelArraySize, referenceIlluminant1/2,
+  // calibrationTransform1/2, colorTransform1/2, forwardMatrix1/2,
+  // blackLevelPattern, profileHueSatMapDimensions
+  // all only necessary for RAW.
+
+  // baseGainFactor marked FUTURE.
+
+  // maxAnalogSensitivity optional for LIMITED device.
+
+  // opticalBlackRegions: No known way to get in V4L2, but not necessary.
+
+  // opaqueRawSize not necessary since RAW_OPAQUE format not supported.
+
+  /* android.shading */
+
+  // No known V4L2 lens shading. But it might be happening,
+  // so we report FAST/HIGH_QUALITY.
+  uint8_t avail_shading_modes[] = {
+    ANDROID_SHADING_MODE_FAST,
+    ANDROID_SHADING_MODE_HIGH_QUALITY};
+  res = info.update(ANDROID_SHADING_AVAILABLE_MODES,
+                    avail_shading_modes, ARRAY_SIZE(avail_shading_modes));
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.statistics */
+
+  // Face detection not supported.
+  uint8_t avail_face_detect_modes[] = {
+    ANDROID_STATISTICS_FACE_DETECT_MODE_OFF};
+  res = info.update(ANDROID_STATISTICS_INFO_AVAILABLE_FACE_DETECT_MODES,
+                    avail_face_detect_modes,
+                    ARRAY_SIZE(avail_face_detect_modes));
+  if (res != android::OK) {
+    return res;
+  }
+
+  int32_t max_face_count = 0;
+  res = info.update(ANDROID_STATISTICS_INFO_MAX_FACE_COUNT,
+                    &max_face_count, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // info.histogramBucketCount, info.maxHistogramCount,
+  // info.maxSharpnessMapValue, info.sharpnessMapSizemarked FUTURE.
+
+  // ON only needs to be supported for RAW capable devices.
+  uint8_t avail_hot_pixel_map_modes[] = {
+    ANDROID_STATISTICS_HOT_PIXEL_MAP_MODE_OFF};
+  res = info.update(ANDROID_STATISTICS_INFO_AVAILABLE_HOT_PIXEL_MAP_MODES,
+                    avail_hot_pixel_map_modes,
+                    ARRAY_SIZE(avail_hot_pixel_map_modes));
+  if (res != android::OK) {
+    return res;
+  }
+
+  // ON only needs to be supported for RAW capable devices.
+  uint8_t avail_lens_shading_map_modes[] = {
+    ANDROID_STATISTICS_LENS_SHADING_MAP_MODE_OFF};
+  res = info.update(ANDROID_STATISTICS_INFO_AVAILABLE_LENS_SHADING_MAP_MODES,
+                    avail_lens_shading_map_modes,
+                    ARRAY_SIZE(avail_lens_shading_map_modes));
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.tonemap. */
+
+  // tonemapping only required for MANUAL_POST_PROCESSING capability.
+
+  /* android.led. */
+
+  // May or may not have LEDs available.
+  if (!mLeds.empty()) {
+    res = info.update(ANDROID_LED_AVAILABLE_LEDS, mLeds.data(), mLeds.size());
+    if (res != android::OK) {
+      return res;
+    }
+  }
+
+  /* android.sync. */
+
+  // "LIMITED devices are strongly encouraged to use a non-negative value.
+  // If UNKNOWN is used here then app developers do not have a way to know
+  // when sensor settings have been applied." - Unfortunately, V4L2 doesn't
+  // really help here either. Could even be that adjusting settings mid-stream
+  // blocks in V4L2, and should be avoided.
+  int32_t max_latency = ANDROID_SYNC_MAX_LATENCY_UNKNOWN;
+  res = info.update(ANDROID_SYNC_MAX_LATENCY,
+                    &max_latency, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.reprocess. */
+
+  // REPROCESSING not supported by this HAL.
+
+  /* android.depth. */
+
+  // DEPTH not supported by this HAL.
+
+  /* Capabilities and android.info. */
+
+  uint8_t hw_level = ANDROID_INFO_SUPPORTED_HARDWARE_LEVEL_LIMITED;
+  res = info.update(ANDROID_INFO_SUPPORTED_HARDWARE_LEVEL,
+                    &hw_level, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  uint8_t capabilities[] = {
+    ANDROID_REQUEST_AVAILABLE_CAPABILITIES_BACKWARD_COMPATIBLE};
+  res = info.update(ANDROID_REQUEST_AVAILABLE_CAPABILITIES,
+                    capabilities, ARRAY_SIZE(capabilities));
+  if (res != android::OK) {
+    return res;
+  }
+
+  // Scan a default request template for included request keys.
+  if (!mTemplatesInitialized) {
+    res = initTemplates();
+    if (res) {
+      return res;
+    }
+  }
+  const camera_metadata_t* preview_request = nullptr;
+  // Search templates from the beginning for a supported one.
+  for (uint8_t template_id = 1; template_id < CAMERA3_TEMPLATE_COUNT;
+       ++template_id) {
+    preview_request = constructDefaultRequestSettings(template_id);
+    if (preview_request != nullptr) {
+      break;
+    }
+  }
+  if (preview_request == nullptr) {
+    HAL_LOGE("No valid templates, can't get request keys.");
+    return -ENODEV;
+  }
+  std::vector<int32_t> avail_request_keys = getMetadataKeys(preview_request);
+  res = info.update(ANDROID_REQUEST_AVAILABLE_REQUEST_KEYS,
+                    avail_request_keys.data(), avail_request_keys.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  // Result keys will be duplicated from the request, plus a few extras.
+  // TODO(b/30035628): additonal available result keys.
+  std::vector<int32_t> avail_result_keys(avail_request_keys);
+  res = info.update(ANDROID_REQUEST_AVAILABLE_RESULT_KEYS,
+                    avail_result_keys.data(), avail_result_keys.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  // Last thing, once all the available characteristics have been added.
+  const camera_metadata_t* static_characteristics = info.getAndLock();
+  std::vector<int32_t> avail_characteristics_keys =
+      getMetadataKeys(static_characteristics);
+  res = info.unlock(static_characteristics);
+  if (res != android::OK) {
+    return res;
+  }
+  avail_characteristics_keys.push_back(
+      ANDROID_REQUEST_AVAILABLE_CHARACTERISTICS_KEYS);
+  res = info.update(ANDROID_REQUEST_AVAILABLE_CHARACTERISTICS_KEYS,
+                    avail_characteristics_keys.data(),
+                    avail_characteristics_keys.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  *out = info.release();
+  return 0;
+}
+
+void V4L2Camera::initDeviceInfo(camera_info_t* info) {
+  HAL_LOG_ENTER();
+
+  // For now, just constants.
+  info->facing = CAMERA_FACING_EXTERNAL;
+  info->orientation = mOrientation;
+  info->resource_cost = 100;
+  info->conflicting_devices = nullptr;
+  info->conflicting_devices_length = 0;
+}
+
+int V4L2Camera::initDevice() {
+  HAL_LOG_ENTER();
+
+  // Templates should be set up if they haven't already been.
+  if (!mTemplatesInitialized) {
+    int res = initTemplates();
+    if (res) {
+      return res;
+    }
+  }
+
+  return 0;
+}
+
+int V4L2Camera::enqueueBuffer(const camera3_stream_buffer_t* camera_buffer) {
+  HAL_LOG_ENTER();
+
+  int res = mV4L2Device->EnqueueBuffer(camera_buffer);
+  if (res) {
+    HAL_LOGE("Device failed to enqueue buffer.");
+    return res;
+  }
+
+  // Turn on the stream.
+  // TODO(b/29334616): Lock around stream on/off access, only start stream
+  // if not already on. (For now, since it's synchronous, it will always be
+  // turned off before another call to this function).
+  res = mV4L2Device->StreamOn();
+  if (res) {
+    HAL_LOGE("Device failed to turn on stream.");
+    return res;
+  }
+
+  // TODO(b/29334616): Enqueueing and dequeueing should be separate worker
+  // threads, not in the same function.
+
+  // Dequeue the buffer.
+  v4l2_buffer result_buffer;
+  res = mV4L2Device->DequeueBuffer(&result_buffer);
+  if (res) {
+    HAL_LOGE("Device failed to dequeue buffer.");
+    return res;
+  }
+
+  // All done, cleanup.
+  // TODO(b/29334616): Lock around stream on/off access, only stop stream if
+  // buffer queue is empty (synchronously, there's only ever 1 buffer in the
+  // queue at a time, so this is safe).
+  res = mV4L2Device->StreamOff();
+  if (res) {
+    HAL_LOGE("Device failed to turn off stream.");
+    return res;
+  }
+
+  return 0;
+}
+
+int V4L2Camera::getResultSettings(camera_metadata** metadata,
+                                  uint64_t* timestamp) {
+  HAL_LOG_ENTER();
+
+  int res = 0;
+  android::CameraMetadata frame_metadata(*metadata);
+
+  // TODO(b/30035628): fill in.
+  // For now just spoof the timestamp to a non-0 value and send it back.
+  int64_t frame_time = 1;
+  res = frame_metadata.update(ANDROID_SENSOR_TIMESTAMP, &frame_time, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  *metadata = frame_metadata.release();
+  *timestamp = frame_time;
+
+  return 0;
+}
+
+int V4L2Camera::initTemplates() {
+  HAL_LOG_ENTER();
+  int res = 0;
+
+  // Device characteristics need to be queried prior
+  // to template setup.
+  if (!mCharacteristicsInitialized) {
+    res = initCharacteristics();
+    if (res) {
+      return res;
+    }
+  }
+
+  // Note: static metadata expects all templates/requests
+  // to provide values for all supported keys.
+
+  android::CameraMetadata base_metadata;
+
+  // Start with defaults for all templates.
+
+  /* android.colorCorrection. */
+
+  uint8_t aberration_mode = ANDROID_COLOR_CORRECTION_ABERRATION_MODE_FAST;
+  res = base_metadata.update(ANDROID_COLOR_CORRECTION_ABERRATION_MODE,
+                             &aberration_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  uint8_t color_correction_mode = ANDROID_COLOR_CORRECTION_MODE_FAST;
+  res = base_metadata.update(ANDROID_COLOR_CORRECTION_MODE,
+                             &color_correction_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // transform and gains are for the unsupported MANUAL_POST_PROCESSING only.
+
+  /* android.control. */
+
+  /*   AE. */
+  uint8_t ae_antibanding_mode = ANDROID_CONTROL_AE_ANTIBANDING_MODE_AUTO;
+  res = base_metadata.update(ANDROID_CONTROL_AE_ANTIBANDING_MODE,
+                             &ae_antibanding_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // Only matters if AE_MODE = OFF
+  int32_t ae_exposure_compensation = 0;
+  res = base_metadata.update(ANDROID_CONTROL_AE_EXPOSURE_COMPENSATION,
+                             &ae_exposure_compensation, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  uint8_t ae_lock = ANDROID_CONTROL_AE_LOCK_OFF;
+  res = base_metadata.update(ANDROID_CONTROL_AE_LOCK, &ae_lock, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  uint8_t ae_mode = ANDROID_CONTROL_AE_MODE_ON;
+  res = base_metadata.update(ANDROID_CONTROL_AE_MODE, &ae_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // AE regions not supported.
+
+  // FPS set per-template.
+
+  uint8_t ae_precapture_trigger = ANDROID_CONTROL_AE_PRECAPTURE_TRIGGER_IDLE;
+  res = base_metadata.update(ANDROID_CONTROL_AE_PRECAPTURE_TRIGGER,
+                             &ae_precapture_trigger, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /*   AF. */
+
+  // AF mode set per-template.
+
+  // AF regions not supported.
+
+  uint8_t af_trigger = ANDROID_CONTROL_AF_TRIGGER_IDLE;
+  res = base_metadata.update(ANDROID_CONTROL_AF_TRIGGER, &af_trigger, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /*   AWB. */
+
+  // Priority: auto > off > Whatever is available.
+  uint8_t default_awb_mode = mAwbModes[0];
+  if (std::count(mAwbModes.begin(), mAwbModes.end(),
+                ANDROID_CONTROL_AWB_MODE_AUTO)) {
+    default_awb_mode = ANDROID_CONTROL_AWB_MODE_AUTO;
+  } else if (std::count(mAwbModes.begin(), mAwbModes.end(),
+                       ANDROID_CONTROL_AWB_MODE_OFF)) {
+    default_awb_mode = ANDROID_CONTROL_AWB_MODE_OFF;
+  }
+  res = base_metadata.update(ANDROID_CONTROL_AWB_MODE, &default_awb_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // AWB regions not supported.
+
+  /*   Other controls. */
+
+  uint8_t effect_mode = ANDROID_CONTROL_EFFECT_MODE_OFF;
+  res = base_metadata.update(ANDROID_CONTROL_EFFECT_MODE, &effect_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  uint8_t control_mode = ANDROID_CONTROL_MODE_AUTO;
+  res = base_metadata.update(ANDROID_CONTROL_MODE, &control_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  uint8_t scene_mode = ANDROID_CONTROL_SCENE_MODE_DISABLED;
+  res = base_metadata.update(ANDROID_CONTROL_SCENE_MODE,
+                             &scene_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  uint8_t video_stabilization = ANDROID_CONTROL_VIDEO_STABILIZATION_MODE_OFF;
+  res = base_metadata.update(ANDROID_CONTROL_VIDEO_STABILIZATION_MODE,
+                             &video_stabilization, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // postRawSensitivityBoost: RAW not supported, leave null.
+
+  /* android.demosaic. */
+
+  // mode marked FUTURE.
+
+  /* android.edge. */
+
+  uint8_t edge_mode = ANDROID_EDGE_MODE_FAST;
+  res = base_metadata.update(ANDROID_EDGE_MODE, &edge_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // strength marked FUTURE.
+
+  /* android.flash. */
+
+  // firingPower, firingTime marked FUTURE.
+
+  uint8_t flash_mode = ANDROID_FLASH_MODE_OFF;
+  res = base_metadata.update(ANDROID_FLASH_MODE, &flash_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.hotPixel. */
+
+  uint8_t hp_mode = ANDROID_HOT_PIXEL_MODE_FAST;
+  res = base_metadata.update(ANDROID_HOT_PIXEL_MODE, &hp_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.jpeg. */
+
+  double gps_coords[] = {/*latitude*/0, /*longitude*/0, /*altitude*/0};
+  res = base_metadata.update(ANDROID_JPEG_GPS_COORDINATES, gps_coords, 3);
+  if (res != android::OK) {
+    return res;
+  }
+
+  uint8_t gps_processing_method[] = "none";
+  res = base_metadata.update(ANDROID_JPEG_GPS_PROCESSING_METHOD,
+                             gps_processing_method,
+                             ARRAY_SIZE(gps_processing_method));
+  if (res != android::OK) {
+    return res;
+  }
+
+  int64_t gps_timestamp = 0;
+  res = base_metadata.update(ANDROID_JPEG_GPS_TIMESTAMP, &gps_timestamp, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // JPEG orientation is relative to sensor orientation (mOrientation).
+  int32_t jpeg_orientation = 0;
+  res = base_metadata.update(ANDROID_JPEG_ORIENTATION, &jpeg_orientation, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // 1-100, larger is higher quality.
+  uint8_t jpeg_quality = 80;
+  res = base_metadata.update(ANDROID_JPEG_QUALITY, &jpeg_quality, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // TODO(b/29580107): If thumbnail quality actually matters/can be adjusted,
+  // adjust this.
+  uint8_t thumbnail_quality = 80;
+  res = base_metadata.update(ANDROID_JPEG_THUMBNAIL_QUALITY,
+                             &thumbnail_quality, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // TODO(b/29580107): Choose a size matching the resolution.
+  int32_t thumbnail_size[] = {0, 0};
+  res = base_metadata.update(ANDROID_JPEG_THUMBNAIL_SIZE, thumbnail_size, 2);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.lens. */
+
+  // Fixed values.
+  res = base_metadata.update(ANDROID_LENS_APERTURE, &mAperture, 1);
+  if (res != android::OK) {
+    return res;
+  }
+  res = base_metadata.update(ANDROID_LENS_FILTER_DENSITY, &mFilterDensity, 1);
+  if (res != android::OK) {
+    return res;
+  }
+  res = base_metadata.update(ANDROID_LENS_FOCAL_LENGTH, &mFocalLength, 1);
+  if (res != android::OK) {
+    return res;
+  }
+  res = base_metadata.update(ANDROID_LENS_FOCUS_DISTANCE, &mFocusDistance, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  uint8_t optical_stabilization = ANDROID_LENS_OPTICAL_STABILIZATION_MODE_OFF;
+  res = base_metadata.update(ANDROID_LENS_OPTICAL_STABILIZATION_MODE,
+                    &optical_stabilization, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.noiseReduction. */
+
+  uint8_t noise_reduction_mode = ANDROID_NOISE_REDUCTION_MODE_FAST;
+  res = base_metadata.update(ANDROID_NOISE_REDUCTION_MODE,
+                             &noise_reduction_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // strength marked FUTURE.
+
+  /* android.request. */
+
+  // Request Id unused by the HAL for now, and these are just
+  // templates, so just fill it in with a dummy.
+  int32_t id = 0;
+  res = base_metadata.update(ANDROID_REQUEST_ID, &id, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // metadataMode marked FUTURE.
+
+  /* android.scaler. */
+
+  // No cropping by default; use the full active array.
+  res = base_metadata.update(ANDROID_SCALER_CROP_REGION, mPixelArraySize.data(),
+                             mPixelArraySize.size());
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.sensor. */
+
+  // exposureTime, sensitivity, testPattern[Data,Mode] not supported.
+
+  // Ignored when AE is OFF.
+  int64_t frame_duration = 33333333L; // 1/30 s.
+  res = base_metadata.update(ANDROID_SENSOR_FRAME_DURATION, &frame_duration, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.shading. */
+
+  uint8_t shading_mode = ANDROID_SHADING_MODE_FAST;
+  res = base_metadata.update(ANDROID_SHADING_MODE, &shading_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.statistics. */
+
+  uint8_t face_detect_mode = ANDROID_STATISTICS_FACE_DETECT_MODE_OFF;
+  res = base_metadata.update(ANDROID_STATISTICS_FACE_DETECT_MODE,
+                             &face_detect_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  // histogramMode, sharpnessMapMode marked FUTURE.
+
+  uint8_t hp_map_mode = ANDROID_STATISTICS_HOT_PIXEL_MAP_MODE_OFF;
+  res = base_metadata.update(ANDROID_STATISTICS_HOT_PIXEL_MAP_MODE,
+                             &hp_map_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  uint8_t lens_shading_map_mode = ANDROID_STATISTICS_LENS_SHADING_MAP_MODE_OFF;
+  res = base_metadata.update(ANDROID_STATISTICS_LENS_SHADING_MAP_MODE,
+                             &lens_shading_map_mode, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.tonemap. */
+
+  // Tonemap only required for MANUAL_POST_PROCESSING capability.
+
+  /* android.led. */
+
+  uint8_t transmit = ANDROID_LED_TRANSMIT_ON;
+  res = base_metadata.update(ANDROID_LED_TRANSMIT, &transmit, 1);
+  if (res != android::OK) {
+    return res;
+  }
+
+  /* android.reprocess */
+
+  // Only needed for REPROCESS capability.
+
+
+  /* Template variable values. */
+
+  // Find the FPS ranges "closest" to a desired range
+  // (minimum abs distance from min to min and max to max).
+  // Find both a fixed rate and a variable rate, for different purposes.
+  std::array<int32_t, 2> desired_flat_fps_range = {{30, 30}};
+  std::array<int32_t, 2> desired_variable_fps_range = {{5, 30}};
+  std::array<int32_t, 2> flat_fps_range;
+  std::array<int32_t, 2> variable_fps_range;
+  int32_t best_flat_distance = std::numeric_limits<int32_t>::max();
+  int32_t best_variable_distance = std::numeric_limits<int32_t>::max();
+  size_t num_fps_ranges = mFpsRanges.num_arrays();
+  for (size_t i = 0; i < num_fps_ranges; ++i) {
+    const int32_t* range = mFpsRanges[i];
+    // Variable fps.
+    int32_t distance = std::abs(range[0] - desired_variable_fps_range[0]) +
+        std::abs(range[1] - desired_variable_fps_range[1]);
+    if (distance < best_variable_distance) {
+      variable_fps_range[0] = range[0];
+      variable_fps_range[1] = range[1];
+      best_variable_distance = distance;
+    }
+    // Flat fps. Only do if range is actually flat.
+    // Note at least one flat range is required,
+    // so something will always be filled in.
+    if (range[0] == range[1]) {
+      distance = std::abs(range[0] - desired_flat_fps_range[0]) +
+          std::abs(range[1] - desired_flat_fps_range[1]);
+      if (distance < best_flat_distance) {
+        flat_fps_range[0] = range[0];
+        flat_fps_range[1] = range[1];
+        best_flat_distance = distance;
+      }
+    }
+  }
+
+  // Priority: continuous > auto > off > whatever is available.
+  bool continuous_still_avail = std::count(
+      mAfModes.begin(), mAfModes.end(),
+      ANDROID_CONTROL_AF_MODE_CONTINUOUS_PICTURE);
+  bool continuous_video_avail = std::count(
+      mAfModes.begin(), mAfModes.end(),
+      ANDROID_CONTROL_AF_MODE_CONTINUOUS_VIDEO);
+  uint8_t non_continuous_af_mode = mAfModes[0];
+  if (std::count(mAfModes.begin(), mAfModes.end(),
+                       ANDROID_CONTROL_AF_MODE_AUTO)) {
+    non_continuous_af_mode = ANDROID_CONTROL_AF_MODE_AUTO;
+  } else if (std::count(mAfModes.begin(), mAfModes.end(),
+                       ANDROID_CONTROL_AF_MODE_OFF)) {
+    non_continuous_af_mode = ANDROID_CONTROL_AF_MODE_OFF;
+  }
+  uint8_t still_af_mode = continuous_still_avail ?
+      ANDROID_CONTROL_AF_MODE_CONTINUOUS_PICTURE : non_continuous_af_mode;
+  uint8_t video_af_mode =  continuous_video_avail ?
+      ANDROID_CONTROL_AF_MODE_CONTINUOUS_VIDEO : non_continuous_af_mode;
+
+  for (uint8_t template_id = 1; template_id < CAMERA3_TEMPLATE_COUNT;
+       ++template_id) {
+    // General differences/support.
+    uint8_t intent;
+    uint8_t af_mode;
+    std::array<int32_t, 2> fps_range;
+    switch(template_id) {
+      case CAMERA3_TEMPLATE_PREVIEW:
+        intent = ANDROID_CONTROL_CAPTURE_INTENT_PREVIEW;
+        af_mode = still_af_mode;
+        fps_range = flat_fps_range;
+        break;
+      case CAMERA3_TEMPLATE_STILL_CAPTURE:
+        intent = ANDROID_CONTROL_CAPTURE_INTENT_STILL_CAPTURE;
+        af_mode = still_af_mode;
+        fps_range = variable_fps_range;
+        break;
+      case CAMERA3_TEMPLATE_VIDEO_RECORD:
+        intent = ANDROID_CONTROL_CAPTURE_INTENT_VIDEO_RECORD;
+        af_mode = video_af_mode;
+        fps_range = flat_fps_range;
+        break;
+      case CAMERA3_TEMPLATE_VIDEO_SNAPSHOT:
+        intent = ANDROID_CONTROL_CAPTURE_INTENT_VIDEO_SNAPSHOT;
+        af_mode = video_af_mode;
+        fps_range = flat_fps_range;
+        break;
+      case CAMERA3_TEMPLATE_ZERO_SHUTTER_LAG:  // Fall through.
+      case CAMERA3_TEMPLATE_MANUAL:  // Fall though.
+      default:
+        // Unsupported/unrecognized. Don't add this template; skip it.
+        continue;
+    }
+
+    // Copy our base metadata and add the new items.
+    android::CameraMetadata template_metadata(base_metadata);
+    res = template_metadata.update(ANDROID_CONTROL_CAPTURE_INTENT, &intent, 1);
+    if (res != android::OK) {
+      return res;
+    }
+    res = template_metadata.update(ANDROID_CONTROL_AE_TARGET_FPS_RANGE,
+                                   fps_range.data(), fps_range.size());
+    if (res != android::OK) {
+      return res;
+    }
+    res = template_metadata.update(ANDROID_CONTROL_AF_MODE, &af_mode, 1);
+    if (res != android::OK) {
+      return res;
+    }
+
+    const camera_metadata_t* template_raw_metadata =
+        template_metadata.getAndLock();
+    res = setTemplate(template_id, template_raw_metadata);
+    if (res != android::OK) {
+      return res;
+    }
+    res = template_metadata.unlock(template_raw_metadata);
+    if (res != android::OK) {
+      return res;
+    }
+  }
+
+  mTemplatesInitialized = true;
+  return 0;
+}
+
+bool V4L2Camera::isSupportedStreamSet(default_camera_hal::Stream** streams,
+                                      int count, uint32_t mode) {
+  HAL_LOG_ENTER();
+
+  if (mode != CAMERA3_STREAM_CONFIGURATION_NORMAL_MODE) {
+    HAL_LOGE("Unsupported stream configuration mode: %d", mode);
+    return false;
+  }
+
+  // This should be checked by the caller, but put here as a sanity check.
+  if (count < 1) {
+    HAL_LOGE("Must request at least 1 stream");
+    return false;
+  }
+
+  // Count the number of streams of each type.
+  int32_t num_input = 0;
+  int32_t num_raw = 0;
+  int32_t num_stalling = 0;
+  int32_t num_non_stalling = 0;
+  for (int i = 0; i < count; ++i) {
+    default_camera_hal::Stream* stream = streams[i];
+
+    if (stream->isInputType()) {
+      ++num_input;
+    }
+
+    if (stream->isOutputType()) {
+      StreamFormat format(*stream);
+      switch (format.Category()) {
+        case kFormatCategoryRaw:
+          ++num_raw;
+        case kFormatCategoryStalling:
+          ++num_stalling;
+          break;
+        case kFormatCategoryNonStalling:
+          ++num_non_stalling;
+          break;
+        case kFormatCategoryUnknown:  // Fall through.
+        default:
+          HAL_LOGE("Unsupported format for stream %d: %d", i, stream->getFormat());
+          return false;
+      }
+    }
+  }
+
+  if (num_input > mMaxInputStreams ||
+      num_raw > mMaxRawOutputStreams ||
+      num_stalling > mMaxStallingOutputStreams ||
+      num_non_stalling > mMaxNonStallingOutputStreams) {
+    HAL_LOGE("Invalid stream configuration: %d input, %d RAW, %d stalling, "
+             "%d non-stalling (max supported: %d input, %d RAW, %d stalling, "
+             "%d non-stalling)", mMaxInputStreams, mMaxRawOutputStreams,
+             mMaxStallingOutputStreams, mMaxNonStallingOutputStreams, num_input,
+             num_raw, num_stalling, num_non_stalling);
+    return false;
+  }
+
+  // TODO(b/29939583): The above logic should be all that's necessary,
+  // but V4L2 doesn't actually support more than 1 stream at a time. So for now,
+  // if not all streams are the same format and size, error. Note that this
+  // means the HAL is not spec-compliant; the requested streams are technically
+  // valid and it is not technically allowed to error once it has reached this
+  // point.
+  int format = streams[0]->getFormat();
+  uint32_t width = streams[0]->getWidth();
+  uint32_t height = streams[0]->getHeight();
+  for (int i = 1; i < count; ++i) {
+    const default_camera_hal::Stream* stream = streams[i];
+    if (stream->getFormat() != format || stream->getWidth() != width ||
+        stream->getHeight() != height) {
+      HAL_LOGE("V4L2 only supports 1 stream configuration at a time "
+               "(stream 0 is format %d, width %u, height %u, "
+               "stream %d is format %d, width %u, height %u).",
+               format, width, height, i, stream->getFormat(),
+               stream->getWidth(), stream->getHeight());
+      return false;
+    }
+  }
+
+  return true;
+}
+
+int V4L2Camera::setupStream(default_camera_hal::Stream* stream,
+                            uint32_t* max_buffers) {
+  HAL_LOG_ENTER();
+
+  if (stream->getRotation() != CAMERA3_STREAM_ROTATION_0) {
+    HAL_LOGE("Rotation %d not supported", stream->getRotation());
+    return -EINVAL;
+  }
+
+  // Doesn't matter what was requested, we always use dataspace V0_JFIF.
+  // Note: according to camera3.h, this isn't allowed, but etalvala@google.com
+  // claims it's underdocumented; the implementation lets the HAL overwrite it.
+  stream->setDataSpace(HAL_DATASPACE_V0_JFIF);
+
+  int res = mV4L2Device->SetFormat(*stream, max_buffers);
+  if (res) {
+    HAL_LOGE("Failed to set device to correct format for stream.");
+    return res;
+  }
+  // Sanity check.
+  if (*max_buffers < 1) {
+    HAL_LOGE("Setting format resulted in an invalid maximum of %u buffers.",
+             *max_buffers);
+    return -ENODEV;
+  }
+
+  return 0;
+}
+
+bool V4L2Camera::isValidCaptureSettings(const camera_metadata_t* settings) {
+  HAL_LOG_ENTER();
+
+  // TODO(b/29335262): reject capture settings this camera isn't capable of.
+  return true;
+}
+
+int V4L2Camera::initCharacteristics() {
+  HAL_LOG_ENTER();
+
+  /* Physical characteristics. */
+  // No way to get these in V4L2, so faked.
+  // Note: While many of these are primarily informative for post-processing
+  // calculations by the app and will potentially cause bad results there,
+  // focal length and physical size are actually used in framework
+  // calculations (field of view, pixel pitch, etc), so faking them may
+  // have unexpected results.
+  mAperture = 2.0;  // RPi camera v2 is f/2.0.
+  mFilterDensity = 0.0;
+  mFocalLength = 3.04;  // RPi camera v2 is 3.04mm.
+  mOrientation = 0;
+  mPhysicalSize = {{3.674, 2.760}};  // RPi camera v2 is 3.674 x 2.760 mm.
+
+  /* Fixed features. */
+
+  // TODO(b/29394024): query VIDIOC_CROPCAP to get pixel rectangle.
+  // Spoofing as 640 x 480 for now.
+  mPixelArraySize = {{/*xmin*/0, /*ymin*/0, /*width*/640, /*height*/480}};
+
+  // V4L2 VIDIOC_CROPCAP doesn't give a way to query this;
+  // it's driver dependent. For now, assume freeform, and
+  // some cameras may just behave badly.
+  // TODO(b/29579652): Figure out a way to determine this.
+  mCropType = ANDROID_SCALER_CROPPING_TYPE_FREEFORM;
+
+  // TODO(b/29394024): query VIDIOC_CROPCAP to get cropping ranges,
+  // and VIDIOC_G_CROP to determine if cropping is supported.
+  // If the ioctl isn't available (or cropping has non-square pixelaspect),
+  // assume no cropping/scaling.
+  // May need to try setting some crops to determine what the driver actually
+  // supports (including testing center vs freeform).
+  mMaxZoom = 1;
+
+  // TODO(b/29394024): query V4L2_CID_EXPOSURE_BIAS.
+  mAeCompensationRange = {{0, 0}};
+  mAeCompensationStep = {1, 1};
+
+  // TODO(b/29394024): query V4L2_CID_3A_LOCK.
+  mAeLockAvailable = ANDROID_CONTROL_AE_LOCK_AVAILABLE_FALSE;
+  mAwbLockAvailable = ANDROID_CONTROL_AWB_LOCK_AVAILABLE_FALSE;
+
+  // TODO(b/29394024): query V4L2_CID_FLASH_LED_MODE.
+  mFlashAvailable = 0;
+
+  // TODO(b/29394024): query V4L2_CID_FOCUS_ABSOLUTE for focus range.
+  mFocusDistance = 0;  // Fixed focus.
+
+  // TODO(b/29939583): V4L2 can only support 1 stream at a time.
+  // For now, just reporting minimum allowable for LIMITED devices.
+  mMaxRawOutputStreams = 0;
+  mMaxStallingOutputStreams = 1;
+  mMaxNonStallingOutputStreams = 2;
+  // Reprocessing not supported.
+  mMaxInputStreams = 0;
+
+  /* Features with (potentially) multiple options. */
+
+  // TODO(b/29394024): query V4L2_CID_EXPOSURE_AUTO for ae modes.
+  mAeModes.push_back(ANDROID_CONTROL_AE_MODE_ON);
+
+  // TODO(b/29394024): query V4L2_CID_POWER_LINE_FREQUENCY.
+  // Auto as the default, since it could mean anything, while OFF would
+  // require guaranteeing no antibanding happens.
+  mAeAntibandingModes.push_back(ANDROID_CONTROL_AE_ANTIBANDING_MODE_AUTO);
+
+  // TODO(b/29394024): query V4L2_CID_FOCUS_AUTO for
+  // CONTINUOUS_VIDEO/CONTINUOUS_PICTURE. V4L2_CID_AUTO_FOCUS_START
+  // supports what Android thinks of as auto focus (single auto focus).
+  // V4L2_CID_AUTO_FOCUS_RANGE allows MACRO.
+  mAfModes.push_back(ANDROID_CONTROL_AF_MODE_OFF);
+
+  // TODO(b/29394024): query V4L2_CID_AUTO_WHITE_BALANCE, or
+  // V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE if available.
+  mAwbModes.push_back(ANDROID_CONTROL_AWB_MODE_AUTO);
+
+  // TODO(b/29394024): query V4L2_CID_SCENE_MODE.
+  mSceneModes.push_back(ANDROID_CONTROL_SCENE_MODE_DISABLED);
+
+  mControlModes.push_back(ANDROID_CONTROL_MODE_AUTO);
+  if (mSceneModes.size() > 1) {
+    // We have some mode other than just DISABLED available.
+    mControlModes.push_back(ANDROID_CONTROL_MODE_USE_SCENE_MODE);
+  }
+
+  // TODO(b/29394024): query V4L2_CID_COLORFX.
+  mEffects.push_back(ANDROID_CONTROL_EFFECT_MODE_OFF);
+
+  // TODO(b/29394024): query V4L2_CID_FLASH_INDICATOR_INTENSITY.
+  // For now, no indicator LED available; nothing to push back.
+  // When there is, push back ANDROID_LED_AVAILABLE_LEDS_TRANSMIT.
+
+  // TODO(b/29394024): query V4L2_CID_IMAGE_STABILIZATION.
+  mOpticalStabilizationModes.push_back(
+      ANDROID_LENS_OPTICAL_STABILIZATION_MODE_OFF);
+  mVideoStabilizationModes.push_back(
+      ANDROID_CONTROL_VIDEO_STABILIZATION_MODE_OFF);
+
+  // Need to support YUV_420_888 and JPEG.
+  // TODO(b/29394024): query VIDIOC_ENUM_FMT.
+  std::vector<uint32_t> formats = {{V4L2_PIX_FMT_JPEG, V4L2_PIX_FMT_YUV420}};
+  // We want to find the smallest maximum frame duration amongst formats.
+  mMaxFrameDuration = std::numeric_limits<int64_t>::max();
+  int64_t min_yuv_frame_duration = std::numeric_limits<int64_t>::max();
+  for (auto format : formats) {
+    int32_t hal_format = StreamFormat::V4L2ToHalPixelFormat(format);
+    if (hal_format < 0) {
+      // Unrecognized/unused format. Skip it.
+      continue;
+    }
+    // TODO(b/29394024): query VIDIOC_ENUM_FRAMESIZES.
+    // For now, just 640x480.
+    ArrayVector<int32_t, 2> frame_sizes;
+    frame_sizes.push_back({{640, 480}});
+    size_t num_frame_sizes = frame_sizes.num_arrays();
+    for (size_t i = 0; i < num_frame_sizes; ++i) {
+      const int32_t* frame_size = frame_sizes[i];
+      mStreamConfigs.push_back({{hal_format, frame_size[0], frame_size[1],
+                ANDROID_SCALER_AVAILABLE_STREAM_CONFIGURATIONS_OUTPUT}});
+
+      // TODO(b/29394024): query VIDIOC_ENUM_FRAMEINTERVALS.
+      // For now, using the emulator max value of .3 sec.
+      int64_t max_frame_duration = 300000000;
+      // For now, min value of 30 fps = 1/30 spf ~= 33333333 ns.
+      // For whatever reason the goldfish/qcom cameras report this as
+      // 33331760, so copying that.
+      int64_t min_frame_duration = 33331760;
+
+      mMinFrameDurations.push_back(
+          {{hal_format, frame_size[0], frame_size[1], min_frame_duration}});
+
+      // In theory max frame duration (min frame rate) should be consistent
+      // between all formats, but we check and only advertise the smallest
+      // available max duration just in case.
+      if (max_frame_duration < mMaxFrameDuration) {
+        mMaxFrameDuration = max_frame_duration;
+      }
+
+      // We only care about min frame duration (max frame rate) for YUV.
+      if (hal_format == HAL_PIXEL_FORMAT_YCbCr_420_888 &&
+          min_frame_duration < min_yuv_frame_duration) {
+        min_yuv_frame_duration = min_frame_duration;
+      }
+
+      // Usually 0 for non-jpeg, non-zero for JPEG.
+      // Randomly choosing absurd 1 sec for JPEG. Unsure what this breaks.
+      int64_t stall_duration = 0;
+      if (hal_format == HAL_PIXEL_FORMAT_BLOB) {
+        stall_duration =  1000000000;
+      }
+      mStallDurations.push_back(
+          {{hal_format, frame_size[0], frame_size[1], stall_duration}});
+    }
+  }
+
+  // This should be at minimum {mi, ma}, {ma, ma} where mi and ma
+  // are min and max frame rates for YUV_420_888. Min should be at most 15.
+  // Convert from frame durations measured in ns.
+  int32_t min_yuv_fps = 1000000000 / mMaxFrameDuration;
+  if (min_yuv_fps > 15) {
+    return -ENODEV;
+  }
+  int32_t max_yuv_fps = 1000000000 / min_yuv_frame_duration;
+  mFpsRanges.push_back({{min_yuv_fps, max_yuv_fps}});
+  mFpsRanges.push_back({{max_yuv_fps, max_yuv_fps}});
+  // Always advertise {30, 30} if max is even higher,
+  // since this is what the default video requests use.
+  if (max_yuv_fps > 30) {
+    mFpsRanges.push_back({{30, 30}});
+  }
+
+  mCharacteristicsInitialized = true;
+  return 0;
+}
+
+}  // namespace v4l2_camera_hal