usbcamera: initial implementation of default usb camera HAL

* Basic skeleton of usb camera hal implementation
* Vendor tag is not supported yet
* Further usb camera hal implementation can be filled into UsbCamera.cpp
* Hot plug thread need to be implemented

Change-Id: Ida63b6d640e32192f5b60a280d9d5106d80e523f

13 files changed, 1876 insertions, 0 deletions

diff --git a/modules/usbcamera/Android.mk b/modules/usbcamera/Android.mk
new file mode 100644
index 0000000..162b158
--- /dev/null
+++ b/modules/usbcamera/Android.mk
@@ -0,0 +1,45 @@
+# Copyright (C) 2015 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.
+
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := camera.usb.default
+LOCAL_MODULE_RELATIVE_PATH := hw
+
+LOCAL_C_INCLUDES += \
+	system/core/include \
+	system/media/camera/include \
+
+LOCAL_SRC_FILES := \
+	CameraHAL.cpp \
+	Camera.cpp \
+	UsbCamera.cpp \
+	Metadata.cpp \
+	Stream.cpp \
+	HotplugThread.cpp \
+
+LOCAL_SHARED_LIBRARIES := \
+	libcamera_metadata \
+	libcutils \
+	liblog \
+	libsync \
+	libutils \
+
+LOCAL_CFLAGS += -Wall -Wextra -fvisibility=hidden
+
+LOCAL_MODULE_TAGS := optional
+
+include $(BUILD_SHARED_LIBRARY)
diff --git a/modules/usbcamera/Camera.cpp b/modules/usbcamera/Camera.cpp
new file mode 100644
index 0000000..cf62f7f
--- /dev/null
+++ b/modules/usbcamera/Camera.cpp
@@ -0,0 +1,537 @@
+/*
+ * Copyright (C) 2015 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_NDEBUG 0
+#define LOG_TAG "Camera"
+#include <cutils/log.h>
+
+#include <cstdlib>
+#include <stdio.h>
+#include <hardware/camera3.h>
+#include <system/camera_metadata.h>
+#include <system/graphics.h>
+#include <utils/Mutex.h>
+#include "CameraHAL.h"
+#include "Metadata.h"
+#include "Stream.h"
+
+#define ATRACE_TAG (ATRACE_TAG_CAMERA | ATRACE_TAG_HAL)
+#include <utils/Trace.h>
+
+#include "Camera.h"
+
+namespace usb_camera_hal {
+
+extern "C" {
+// Shim passed to the framework to close an opened device.
+static int close_device(hw_device_t* dev) {
+    camera3_device_t* cam_dev = reinterpret_cast<camera3_device_t*>(dev);
+    Camera* cam = static_cast<Camera*>(cam_dev->priv);
+    return cam->close();
+}
+
+// Get handle to camera from device priv data
+static Camera *camdev_to_camera(const camera3_device_t *dev) {
+    return reinterpret_cast<Camera*>(dev->priv);
+}
+
+static int initialize(const camera3_device_t *dev,
+        const camera3_callback_ops_t *callback_ops) {
+    return camdev_to_camera(dev)->initialize(callback_ops);
+}
+
+static int configure_streams(const camera3_device_t *dev,
+        camera3_stream_configuration_t *stream_list) {
+    return camdev_to_camera(dev)->configureStreams(stream_list);
+}
+
+static const camera_metadata_t *construct_default_request_settings(
+        const camera3_device_t *dev, int type) {
+    return camdev_to_camera(dev)->constructDefaultRequestSettings(type);
+}
+
+static int process_capture_request(const camera3_device_t *dev,
+        camera3_capture_request_t *request) {
+    return camdev_to_camera(dev)->processCaptureRequest(request);
+}
+
+static void dump(const camera3_device_t *dev, int fd) {
+    camdev_to_camera(dev)->dump(fd);
+}
+
+static int flush(const camera3_device_t *dev) {
+    return camdev_to_camera(dev)->flush();
+}
+
+} // extern "C"
+
+const camera3_device_ops_t Camera::sOps = {
+    .initialize = usb_camera_hal::initialize,
+    .configure_streams = usb_camera_hal::configure_streams,
+    .register_stream_buffers = NULL,
+    .construct_default_request_settings
+        = usb_camera_hal::construct_default_request_settings,
+    .process_capture_request = usb_camera_hal::process_capture_request,
+    .get_metadata_vendor_tag_ops = NULL,
+    .dump = usb_camera_hal::dump,
+    .flush = usb_camera_hal::flush,
+    .reserved = {0},
+};
+
+Camera::Camera(int id)
+          : mId(id),
+            mStaticInfo(NULL),
+            mBusy(false),
+            mCallbackOps(NULL),
+            mSettings(NULL),
+            mIsInitialized(false) {
+    memset(&mTemplates, 0, sizeof(mTemplates));
+    memset(&mDevice, 0, sizeof(mDevice));
+    mDevice.common.tag    = HARDWARE_DEVICE_TAG;
+    // TODO: Upgrade to HAL3.3
+    mDevice.common.version = CAMERA_DEVICE_API_VERSION_3_2;
+    mDevice.common.close  = close_device;
+    mDevice.ops           = const_cast<camera3_device_ops_t*>(&sOps);
+    mDevice.priv          = this;
+}
+
+Camera::~Camera() {
+    if (mStaticInfo != NULL) {
+        free_camera_metadata(mStaticInfo);
+    }
+
+    for (int i = 0; i < CAMERA3_TEMPLATE_COUNT; i++) {
+        free_camera_metadata(mTemplates[i]);
+    }
+
+    if (mSettings != NULL) {
+        free_camera_metadata(mSettings);
+    }
+}
+
+int Camera::open(const hw_module_t *module, hw_device_t **device) {
+    ALOGI("%s:%d: Opening camera device", __func__, mId);
+    ATRACE_CALL();
+    android::Mutex::Autolock al(mDeviceLock);
+
+    if (mBusy) {
+        ALOGE("%s:%d: Error! Camera device already opened", __func__, mId);
+        return -EBUSY;
+    }
+
+    mBusy = true;
+    mDevice.common.module = const_cast<hw_module_t*>(module);
+    *device = &mDevice.common;
+    return openDevice();
+}
+
+int Camera::getInfo(struct camera_info *info) {
+    android::Mutex::Autolock al(mStaticInfoLock);
+
+    // TODO: update to CAMERA_FACING_EXTERNAL once the HAL API changes are merged.
+    info->facing = CAMERA_FACING_FRONT;
+    info->orientation = 0;
+    info->device_version = mDevice.common.version;
+    if (mStaticInfo == NULL) {
+        initStaticInfo();
+    }
+    info->static_camera_characteristics = mStaticInfo;
+    return 0;
+}
+
+void Camera::updateInfo() {
+    android::Mutex::Autolock al(mStaticInfoLock);
+    initStaticInfo();
+}
+
+int Camera::close() {
+    ALOGI("%s:%d: Closing camera device", __func__, mId);
+    ATRACE_CALL();
+    android::Mutex::Autolock al(mDeviceLock);
+
+    if (!mBusy) {
+        ALOGE("%s:%d: Error! Camera device not open", __func__, mId);
+        return -EINVAL;
+    }
+
+    mBusy = false;
+    mIsInitialized = false;
+    return closeDevice();
+}
+
+int Camera::initialize(const camera3_callback_ops_t *callback_ops) {
+    int res;
+
+    ALOGV("%s:%d: callback_ops=%p", __func__, mId, callback_ops);
+    ATRACE_CALL();
+    android::Mutex::Autolock al(mDeviceLock);
+
+    mCallbackOps = callback_ops;
+    // per-device specific initialization
+    res = initDevice();
+    if (res != 0) {
+        ALOGE("%s:%d: Failed to initialize device!", __func__, mId);
+        return res;
+    }
+
+    mIsInitialized = true;
+    return 0;
+}
+
+int Camera::configureStreams(camera3_stream_configuration_t *stream_config) {
+    camera3_stream_t *astream;
+    android::Vector<Stream *> newStreams;
+
+    ALOGV("%s:%d: stream_config=%p", __func__, mId, stream_config);
+    ATRACE_CALL();
+    android::Mutex::Autolock al(mDeviceLock);
+    if (!mIsInitialized) {
+        ALOGE("Device is not initialized yet");
+        return -EINVAL;
+    }
+
+    if (stream_config == NULL) {
+        ALOGE("%s:%d: NULL stream configuration array", __func__, mId);
+        return -EINVAL;
+    }
+    if (stream_config->num_streams == 0) {
+        ALOGE("%s:%d: Empty stream configuration array", __func__, mId);
+        return -EINVAL;
+    }
+
+    ALOGV("%s:%d: Number of Streams: %d", __func__, mId,
+            stream_config->num_streams);
+    // Mark all current streams unused for now
+    for (size_t i = 0; i < mStreams.size(); i++) {
+        mStreams[i]->mReuse = false;
+    }
+    // Fill new stream array with reused streams and new streams
+    for (unsigned int i = 0; i < stream_config->num_streams; i++) {
+        astream = stream_config->streams[i];
+        if (astream->max_buffers > 0) {
+            ALOGV("%s:%d: Reusing stream %d", __func__, mId, i);
+            newStreams.add(reuseStreamLocked(astream));
+        } else {
+            ALOGV("%s:%d: Creating new stream %d", __func__, mId, i);
+            newStreams.add(new Stream(mId, astream));
+        }
+
+        if (newStreams[i] == NULL) {
+            ALOGE("%s:%d: Error processing stream %d", __func__, mId, i);
+            goto err_out;
+        }
+        astream->priv = reinterpret_cast<void *>(newStreams[i]);
+    }
+
+    // Verify the set of streams in aggregate
+    if (!isValidStreamSetLocked(newStreams)) {
+        ALOGE("%s:%d: Invalid stream set", __func__, mId);
+        goto err_out;
+    }
+
+    // Set up all streams (calculate usage/max_buffers for each)
+    setupStreamsLocked(newStreams);
+
+    // Destroy all old streams and replace stream array with new one
+    destroyStreamsLocked(mStreams);
+    mStreams = newStreams;
+
+    // Clear out last seen settings metadata
+    updateSettingsLocked(NULL);
+    return 0;
+
+err_out:
+    // Clean up temporary streams, preserve existing mStreams
+    destroyStreamsLocked(newStreams);
+    return -EINVAL;
+}
+
+void Camera::destroyStreamsLocked(android::Vector<Stream *> &streams) {
+    for (size_t i = 0; i < streams.size(); i++) {
+        delete streams[i];
+    }
+    streams.clear();
+}
+
+Stream *Camera::reuseStreamLocked(camera3_stream_t *astream) {
+    Stream *priv = reinterpret_cast<Stream*>(astream->priv);
+    // Verify the re-used stream's parameters match
+    if (!priv->isValidReuseStream(mId, astream)) {
+        ALOGE("%s:%d: Mismatched parameter in reused stream", __func__, mId);
+        return NULL;
+    }
+    // Mark stream to be reused
+    priv->mReuse = true;
+    return priv;
+}
+
+bool Camera::isValidStreamSetLocked(const android::Vector<Stream *> &streams) {
+    int inputs = 0;
+    int outputs = 0;
+
+    if (streams.isEmpty()) {
+        ALOGE("%s:%d: Zero count stream configuration streams", __func__, mId);
+        return false;
+    }
+    // Validate there is at most one input stream and at least one output stream
+    for (size_t i = 0; i < streams.size(); i++) {
+        // A stream may be both input and output (bidirectional)
+        if (streams[i]->isInputType())
+            inputs++;
+        if (streams[i]->isOutputType())
+            outputs++;
+    }
+    ALOGV("%s:%d: Configuring %d output streams and %d input streams",
+            __func__, mId, outputs, inputs);
+    if (outputs < 1) {
+        ALOGE("%s:%d: Stream config must have >= 1 output", __func__, mId);
+        return false;
+    }
+    if (inputs > 1) {
+        ALOGE("%s:%d: Stream config must have <= 1 input", __func__, mId);
+        return false;
+    }
+    // TODO: check for correct number of Bayer/YUV/JPEG/Encoder streams
+    return true;
+}
+
+void Camera::setupStreamsLocked(android::Vector<Stream *> &streams) {
+    /*
+     * This is where the HAL has to decide internally how to handle all of the
+     * streams, and then produce usage and max_buffer values for each stream.
+     * Note, the stream vector has been checked before this point for ALL invalid
+     * conditions, so it must find a successful configuration for this stream
+     * array.  The HAL may not return an error from this point.
+     *
+     * TODO: we just set all streams to be the same dummy values;
+     * real implementations will want to avoid USAGE_SW_{READ|WRITE}_OFTEN.
+     */
+    for (size_t i = 0; i < streams.size(); i++) {
+        uint32_t usage = 0;
+
+        if (streams[i]->isOutputType())
+            usage |= GRALLOC_USAGE_SW_WRITE_OFTEN |
+                     GRALLOC_USAGE_HW_CAMERA_WRITE;
+        if (streams[i]->isInputType())
+            usage |= GRALLOC_USAGE_SW_READ_OFTEN |
+                     GRALLOC_USAGE_HW_CAMERA_READ;
+
+        streams[i]->setUsage(usage);
+        streams[i]->setMaxBuffers(1);
+    }
+}
+
+bool Camera::isValidTemplateType(int type) {
+    return type >= 1 && type < CAMERA3_TEMPLATE_COUNT;
+}
+
+const camera_metadata_t* Camera::constructDefaultRequestSettings(int type) {
+    ALOGV("%s:%d: type=%d", __func__, mId, type);
+    android::Mutex::Autolock al(mDeviceLock);
+
+    if (!isValidTemplateType(type)) {
+        ALOGE("%s:%d: Invalid template request type: %d", __func__, mId, type);
+        return NULL;
+    }
+
+    // DO NOT try to initialize the device here, it will be guaranteed deadlock.
+    if (!mIsInitialized) {
+        ALOGE("Device is not initialized yet");
+        return NULL;
+    }
+
+    return mTemplates[type];
+}
+
+// This implementation is a copy-paste, probably we should override (or move) this to
+// device specific class.
+int Camera::processCaptureRequest(camera3_capture_request_t *request) {
+    camera3_capture_result result;
+    ALOGV("%s:%d: request=%p", __func__, mId, request);
+    ATRACE_CALL();
+    android::Mutex::Autolock al(mDeviceLock);
+
+    if (request == NULL) {
+        ALOGE("%s:%d: NULL request recieved", __func__, mId);
+        return -EINVAL;
+    }
+
+    ALOGV("%s:%d: Request Frame:%d Settings:%p", __func__, mId,
+            request->frame_number, request->settings);
+
+    // NULL indicates use last settings
+    if (request->settings == NULL) {
+        if (mSettings == NULL) {
+            ALOGE("%s:%d: NULL settings without previous set Frame:%d Req:%p",
+                    __func__, mId, request->frame_number, request);
+            return -EINVAL;
+        }
+    } else {
+        updateSettingsLocked(request->settings);
+    }
+
+    if (request->input_buffer != NULL) {
+        ALOGV("%s:%d: Reprocessing input buffer is not supported yet", __func__, mId);
+        return -EINVAL;
+    } else {
+        ALOGV("%s:%d: Capturing new frame.", __func__, mId);
+
+        if (!isValidCaptureSettings(request->settings)) {
+            ALOGE("%s:%d: Invalid settings for capture request: %p",
+                    __func__, mId, request->settings);
+            return -EINVAL;
+        }
+    }
+
+    if (request->num_output_buffers <= 0) {
+        ALOGE("%s:%d: Invalid number of output buffers: %d", __func__, mId,
+                request->num_output_buffers);
+        return -EINVAL;
+    }
+    result.num_output_buffers = request->num_output_buffers;
+    result.output_buffers = new camera3_stream_buffer_t[result.num_output_buffers];
+    for (unsigned int i = 0; i < request->num_output_buffers; i++) {
+        int res = processCaptureBuffer(&request->output_buffers[i],
+                const_cast<camera3_stream_buffer_t*>(&result.output_buffers[i]));
+        if (res) {
+            delete [] result.output_buffers;
+            // TODO: this should probably be a total device failure; transient for now
+            return -EINVAL;
+        }
+    }
+
+    result.frame_number = request->frame_number;
+    // TODO: return actual captured/reprocessed settings
+    result.result = request->settings;
+    // TODO: asynchronously return results
+    notifyShutter(request->frame_number, 0);
+    mCallbackOps->process_capture_result(mCallbackOps, &result);
+
+    // Free up capture result related resources, HAL owns the capture result, and it
+    // is only valid during the process_capture_result call.
+    delete[] result.output_buffers;
+
+    return 0;
+}
+
+int Camera::flush() {
+    int res;
+
+    ALOGV("%s:%d: flush device", __func__, mId);
+    // per-device specific flush
+    res = flushDevice();
+    if (res != 0) {
+        ALOGE("%s:%d: Failed to flush device!", __func__, mId);
+        return res;
+    }
+    return 0;
+}
+
+void Camera::updateSettingsLocked(const camera_metadata_t *new_settings) {
+    if (mSettings != NULL) {
+        free_camera_metadata(mSettings);
+        mSettings = NULL;
+    }
+
+    if (new_settings != NULL)
+        mSettings = clone_camera_metadata(new_settings);
+}
+
+void Camera::notifyShutter(uint32_t frame_number, uint64_t timestamp) {
+    int res;
+    struct timespec ts;
+
+    // If timestamp is 0, get timestamp from right now instead
+    if (timestamp == 0) {
+        ALOGW("%s:%d: No timestamp provided, using CLOCK_BOOTTIME",
+                __func__, mId);
+        res = clock_gettime(CLOCK_BOOTTIME, &ts);
+        if (res == 0) {
+            timestamp = ts.tv_sec * 1000000000ULL + ts.tv_nsec;
+        } else {
+            ALOGE("%s:%d: No timestamp and failed to get CLOCK_BOOTTIME %s(%d)",
+                    __func__, mId, strerror(errno), errno);
+        }
+    }
+    camera3_notify_msg_t m;
+    memset(&m, 0, sizeof(m));
+    m.type = CAMERA3_MSG_SHUTTER;
+    m.message.shutter.frame_number = frame_number;
+    m.message.shutter.timestamp = timestamp;
+    mCallbackOps->notify(mCallbackOps, &m);
+}
+
+void Camera::dump(int fd) {
+    ALOGV("%s:%d: Dumping to fd %d", __func__, mId, fd);
+    ATRACE_CALL();
+    android::Mutex::Autolock al(mDeviceLock);
+
+    dprintf(fd, "Camera ID: %d (Busy: %d)\n", mId, mBusy);
+
+    // TODO: dump all settings
+    dprintf(fd, "Most Recent Settings: (%p)\n", mSettings);
+
+    dprintf(fd, "Number of streams: %d\n", mStreams.size());
+    for (size_t i = 0; i < mStreams.size(); i++) {
+        dprintf(fd, "Stream %d/%d:\n", i, mStreams.size());
+        mStreams[i]->dump(fd);
+    }
+}
+
+const char* Camera::templateToString(int type) {
+    switch (type) {
+    case CAMERA3_TEMPLATE_PREVIEW:
+        return "CAMERA3_TEMPLATE_PREVIEW";
+    case CAMERA3_TEMPLATE_STILL_CAPTURE:
+        return "CAMERA3_TEMPLATE_STILL_CAPTURE";
+    case CAMERA3_TEMPLATE_VIDEO_RECORD:
+        return "CAMERA3_TEMPLATE_VIDEO_RECORD";
+    case CAMERA3_TEMPLATE_VIDEO_SNAPSHOT:
+        return "CAMERA3_TEMPLATE_VIDEO_SNAPSHOT";
+    case CAMERA3_TEMPLATE_ZERO_SHUTTER_LAG:
+        return "CAMERA3_TEMPLATE_ZERO_SHUTTER_LAG";
+    case CAMERA3_TEMPLATE_MANUAL:
+        return "CAMERA3_TEMPLATE_MANUAL";
+    }
+
+    return "Invalid template type!";
+}
+
+int Camera::setTemplate(int type, camera_metadata_t *settings) {
+    android::Mutex::Autolock al(mDeviceLock);
+
+    if (!isValidTemplateType(type)) {
+        ALOGE("%s:%d: Invalid template request type: %d", __func__, mId, type);
+        return -EINVAL;
+    }
+
+    if (mTemplates[type] != NULL) {
+        ALOGE("%s:%d: Setting already constructed template type %s(%d)",
+                __func__, mId, templateToString(type), type);
+        return -EINVAL;
+    }
+
+    // Make a durable copy of the underlying metadata
+    mTemplates[type] = clone_camera_metadata(settings);
+    if (mTemplates[type] == NULL) {
+        ALOGE("%s:%d: Failed to clone metadata %p for template type %s(%d)",
+                __func__, mId, settings, templateToString(type), type);
+        return -EINVAL;
+    }
+    return 0;
+}
+
+} // namespace usb_camera_hal
diff --git a/modules/usbcamera/Camera.h b/modules/usbcamera/Camera.h
new file mode 100644
index 0000000..6419c7d
--- /dev/null
+++ b/modules/usbcamera/Camera.h
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2015 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 CAMERA_H_
+#define CAMERA_H_
+
+#include <hardware/hardware.h>
+#include <hardware/camera3.h>
+#include <utils/Mutex.h>
+#include <utils/Vector.h>
+#include "Metadata.h"
+#include <sync/sync.h>
+#include "Stream.h"
+
+#define CAMERA_SYNC_TIMEOUT_MS 5000
+
+namespace usb_camera_hal {
+// Camera represents a physical camera on a device.
+// This is constructed when the HAL module is loaded, one per physical camera.
+// It is opened by the framework, and must be closed before it can be opened
+// again.
+// This is an abstract class, containing all logic and data shared between all
+// camera devices.
+class Camera {
+    public:
+        // id is used to distinguish cameras. 0 <= id < NUM_CAMERAS.
+        // module is a handle to the HAL module, used when the device is opened.
+        Camera(int id);
+        virtual ~Camera();
+
+        // Common Camera Device Operations (see <hardware/camera_common.h>)
+        int open(const hw_module_t *module, hw_device_t **device);
+        int getInfo(struct camera_info *info);
+        int close();
+
+        // Camera v3 Device Operations (see <hardware/camera3.h>)
+        int initialize(const camera3_callback_ops_t *callback_ops);
+        int configureStreams(camera3_stream_configuration_t *stream_list);
+        const camera_metadata_t *constructDefaultRequestSettings(int type);
+        int processCaptureRequest(camera3_capture_request_t *request);
+        int flush();
+        void dump(int fd);
+
+        // Update static camera characteristics. This method could be called by
+        // HAL hotplug thread when camera is plugged.
+        void updateInfo();
+
+    protected:
+        // Initialize static camera characteristics.
+        virtual int initStaticInfo() = 0;
+        // Verify settings are valid for a capture
+        virtual bool isValidCaptureSettings(const camera_metadata_t *) = 0;
+        // Separate open method for individual devices
+        virtual int openDevice() = 0;
+        // Separate initialization method for individual devices when opened
+        virtual int initDevice() = 0;
+        // Flush camera pipeline for each individual device
+        virtual int flushDevice() = 0;
+        // Separate close method for individual devices
+        virtual int closeDevice() = 0;
+        // Capture and file an output buffer for an input buffer.
+        virtual int processCaptureBuffer(const camera3_stream_buffer_t *in,
+                camera3_stream_buffer_t *out) = 0;
+        // Accessor method used by initDevice() to set the templates' metadata
+        int setTemplate(int type, camera_metadata_t *settings);
+        // Prettyprint template names
+        const char* templateToString(int type);
+        // Process an output buffer
+
+        // Identifier used by framework to distinguish cameras
+        const int mId;
+        // Metadata containing persistent camera characteristics
+        Metadata mMetadata;
+        // camera_metadata structure containing static characteristics
+        camera_metadata_t *mStaticInfo;
+
+    private:
+        // Camera device handle returned to framework for use
+        camera3_device_t mDevice;
+        // Reuse a stream already created by this device. Must be called with mDeviceLock held.
+        Stream *reuseStreamLocked(camera3_stream_t *astream);
+        // Destroy all streams in a stream array, and the array itself. Must be called with
+        // mDeviceLock held.
+        void destroyStreamsLocked(android::Vector<Stream *> &streams);
+        // Verify a set of streams is valid in aggregate. Must be called with mDeviceLock held.
+        bool isValidStreamSetLocked(const android::Vector<Stream *> &streams);
+        // Calculate usage and max_bufs of each stream. Must be called with mDeviceLock held.
+        void setupStreamsLocked(android::Vector<Stream *> &streams);
+        // Update new settings for re-use and clean up old settings. Must be called with
+        // mDeviceLock held.
+        void updateSettingsLocked(const camera_metadata_t *new_settings);
+        // Send a shutter notify message with start of exposure time
+        void notifyShutter(uint32_t frame_number, uint64_t timestamp);
+        // Is type a valid template type (and valid index into mTemplates)
+        bool isValidTemplateType(int type);
+
+        // Busy flag indicates camera is in use
+        bool mBusy;
+        // Camera device operations handle shared by all devices
+        const static camera3_device_ops_t sOps;
+        // Methods used to call back into the framework
+        const camera3_callback_ops_t *mCallbackOps;
+        // Lock protecting the Camera object for modifications
+        android::Mutex mDeviceLock;
+        // Lock protecting only static camera characteristics, which may
+        // be accessed without the camera device open
+        android::Mutex mStaticInfoLock;
+        // Array of handles to streams currently in use by the device
+        android::Vector<Stream *> mStreams;
+        // Static array of standard camera settings templates
+        camera_metadata_t *mTemplates[CAMERA3_TEMPLATE_COUNT];
+        // Most recent request settings seen, memoized to be reused
+        camera_metadata_t *mSettings;
+        bool mIsInitialized;
+};
+} // namespace usb_camera_hal
+
+#endif // CAMERA_H_
diff --git a/modules/usbcamera/CameraHAL.cpp b/modules/usbcamera/CameraHAL.cpp
new file mode 100644
index 0000000..98111ef
--- /dev/null
+++ b/modules/usbcamera/CameraHAL.cpp
@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2015 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_NDEBUG 0
+#define LOG_TAG "UsbCameraHAL"
+#include <cutils/log.h>
+
+#include <cstdlib>
+#include <hardware/camera_common.h>
+#include <hardware/hardware.h>
+#include "UsbCamera.h"
+#include "CameraHAL.h"
+
+/*
+ * This file serves as the entry point to the HAL.  It contains the module
+ * structure and functions used by the framework to load and interface to this
+ * HAL, as well as the handles to the individual camera devices.
+ */
+
+namespace usb_camera_hal {
+
+static CameraHAL gCameraHAL;
+
+CameraHAL::CameraHAL()
+  : mCallbacks(NULL) {
+    // Should not allocate the camera devices for now, as it is unclear if the device is plugged.
+
+    // Start hotplug thread
+    mHotplugThread = new HotplugThread(this);
+    mHotplugThread->run("usb-camera-hotplug");
+}
+
+CameraHAL::~CameraHAL() {
+    // Stop hotplug thread
+    {
+        android::Mutex::Autolock al(mModuleLock);
+        if (mHotplugThread != NULL) {
+            mHotplugThread->requestExit();
+        }
+
+        // Delete camera device from mCameras
+    }
+
+    // Joining done without holding mLock, otherwise deadlocks may ensue
+    // as the threads try to access parent states.
+    if (mHotplugThread != NULL) {
+        mHotplugThread->join();
+    }
+
+    delete mHotplugThread;
+}
+
+int CameraHAL::getNumberOfCameras() {
+    android::Mutex::Autolock al(mModuleLock);
+    ALOGV("%s: %d", __func__, mCameras.size());
+    return static_cast<int>(mCameras.size());
+}
+
+int CameraHAL::getCameraInfo(int id, struct camera_info* info) {
+    android::Mutex::Autolock al(mModuleLock);
+    ALOGV("%s: camera id %d: info=%p", __func__, id, info);
+    if (id < 0 || id >= static_cast<int>(mCameras.size())) {
+        ALOGE("%s: Invalid camera id %d", __func__, id);
+        return -ENODEV;
+    }
+
+    return mCameras[id]->getInfo(info);
+}
+
+int CameraHAL::setCallbacks(const camera_module_callbacks_t *callbacks) {
+    ALOGV("%s : callbacks=%p", __func__, callbacks);
+    mCallbacks = callbacks;
+    return 0;
+}
+
+int CameraHAL::open(const hw_module_t* mod, const char* name, hw_device_t** dev) {
+    int id;
+    char *nameEnd;
+
+    android::Mutex::Autolock al(mModuleLock);
+    ALOGV("%s: module=%p, name=%s, device=%p", __func__, mod, name, dev);
+    if (*name == '\0') {
+        ALOGE("%s: Invalid camera id name is NULL", __func__);
+        return -EINVAL;
+    }
+    id = strtol(name, &nameEnd, 10);
+    if (*nameEnd != '\0') {
+        ALOGE("%s: Invalid camera id name %s", __func__, name);
+        return -EINVAL;
+    } else if (id < 0 || id >= static_cast<int>(mCameras.size())) {
+        ALOGE("%s: Invalid camera id %d", __func__, id);
+        return -ENODEV;
+    }
+    return mCameras[id]->open(mod, dev);
+}
+
+extern "C" {
+
+static int get_number_of_cameras() {
+    return gCameraHAL.getNumberOfCameras();
+}
+
+static int get_camera_info(int id, struct camera_info* info) {
+    return gCameraHAL.getCameraInfo(id, info);
+}
+
+static int set_callbacks(const camera_module_callbacks_t *callbacks) {
+    return gCameraHAL.setCallbacks(callbacks);
+}
+
+static int open_dev(const hw_module_t* mod, const char* name, hw_device_t** dev) {
+    return gCameraHAL.open(mod, name, dev);
+}
+
+static hw_module_methods_t gCameraModuleMethods = {
+    open : open_dev
+};
+
+camera_module_t HAL_MODULE_INFO_SYM __attribute__ ((visibility("default"))) = {
+    common : {
+        tag                : HARDWARE_MODULE_TAG,
+        module_api_version : CAMERA_MODULE_API_VERSION_2_4,
+        hal_api_version    : HARDWARE_HAL_API_VERSION,
+        id                 : CAMERA_HARDWARE_MODULE_ID,
+        name               : "Default USB Camera HAL",
+        author             : "The Android Open Source Project",
+        methods            : &gCameraModuleMethods,
+        dso                : NULL,
+        reserved           : {0},
+    },
+    get_number_of_cameras : get_number_of_cameras,
+    get_camera_info       : get_camera_info,
+    set_callbacks         : set_callbacks,
+    get_vendor_tag_ops    : NULL,
+    open_legacy           : NULL,
+    set_torch_mode        : NULL,
+    reserved              : {0},
+};
+} // extern "C"
+
+} // namespace usb_camera_hal
diff --git a/modules/usbcamera/CameraHAL.h b/modules/usbcamera/CameraHAL.h
new file mode 100644
index 0000000..1770d95
--- /dev/null
+++ b/modules/usbcamera/CameraHAL.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2015 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 CAMERA_HAL_H_
+#define CAMERA_HAL_H_
+
+#include <hardware/hardware.h>
+#include <hardware/camera_common.h>
+#include <utils/Vector.h>
+#include <utils/Mutex.h>
+#include "HotplugThread.h"
+#include "Camera.h"
+
+namespace usb_camera_hal {
+
+class HotplugThread;
+
+/**
+ * CameraHAL contains all module state that isn't specific to an individual camera device
+ */
+class CameraHAL {
+    public:
+        CameraHAL();
+        ~CameraHAL();
+
+        // Camera Module Interface (see <hardware/camera_common.h>)
+        int getNumberOfCameras();
+        int getCameraInfo(int camera_id, struct camera_info *info);
+        int setCallbacks(const camera_module_callbacks_t *callbacks);
+        void getVendorTagOps(vendor_tag_ops_t* ops);
+
+        // Hardware Module Interface (see <hardware/hardware.h>)
+        int open(const hw_module_t* mod, const char* name, hw_device_t** dev);
+
+    private:
+        // Callback handle
+        const camera_module_callbacks_t *mCallbacks;
+        android::Vector<Camera*> mCameras;
+        // Lock to protect the module method calls.
+        android::Mutex mModuleLock;
+        // Hot plug thread managing camera hot plug.
+        HotplugThread *mHotplugThread;
+
+};
+} // namespace usb_camera_hal
+
+#endif // CAMERA_HAL_H_
diff --git a/modules/usbcamera/HotplugThread.cpp b/modules/usbcamera/HotplugThread.cpp
new file mode 100644
index 0000000..6c65086
--- /dev/null
+++ b/modules/usbcamera/HotplugThread.cpp
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2015 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_NDEBUG 0
+#define LOG_TAG "HotplugThread"
+#include <cutils/log.h>
+
+#include "HotplugThread.h"
+
+namespace usb_camera_hal {
+
+HotplugThread::HotplugThread(CameraHAL *hal)
+    : mModule(hal) {
+
+}
+
+HotplugThread::~HotplugThread() {
+
+}
+
+void HotplugThread::requestExit() {
+    // Call parent to set up shutdown
+    Thread::requestExit();
+
+    // Cleanup other states?
+}
+
+bool HotplugThread::threadLoop() {
+
+    /**
+     * Check camera connection status change, if connected, do below:
+     * 1. Create camera device, add to mCameras.
+     * 2. Init static info (mCameras[id]->initStaticInfo())
+     * 3. Notify on_status_change callback
+     *
+     * If unconnected, similarly, do below:
+     * 1. Destroy camera device and remove it from mCameras.
+     * 2. Notify on_status_change callback
+     *
+     * DO NOT have a tight polling loop here, to avoid excessive CPU utilization.
+     */
+
+    return true;
+}
+
+} // namespace usb_camera_hal
diff --git a/modules/usbcamera/HotplugThread.h b/modules/usbcamera/HotplugThread.h
new file mode 100644
index 0000000..a13adb7
--- /dev/null
+++ b/modules/usbcamera/HotplugThread.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2015 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 HOTPLUG_THREAD_H_
+#define HOTPLUG_THREAD_H_
+
+#include <utils/Thread.h>
+#include "CameraHAL.h"
+
+namespace usb_camera_hal {
+/**
+ * Thread for managing usb camera hotplug. It does below:
+ * 1. Monitor camera hotplug status, and notify the status changes by calling
+ *    module callback methods.
+ * 2. When camera is plugged, create camera device instance, initialize the camera
+ *    static info. When camera is unplugged, destroy the camera device instance and
+ *    static metadata. As an optimization option, the camera device instance (including
+ *    the static info) could be cached when the same camera plugged/unplugged multiple
+ *    times.
+ */
+
+class CameraHAL;
+
+class HotplugThread : public android::Thread {
+
+    public:
+        HotplugThread(CameraHAL *hal);
+        ~HotplugThread();
+
+        // Override below two methods for proper cleanup.
+        virtual bool threadLoop();
+        virtual void requestExit();
+
+    private:
+        CameraHAL *mModule;
+};
+
+} // namespace usb_camera_hal
+
+#endif // HOTPLUG_THREAD_H_
diff --git a/modules/usbcamera/Metadata.cpp b/modules/usbcamera/Metadata.cpp
new file mode 100644
index 0000000..f243834
--- /dev/null
+++ b/modules/usbcamera/Metadata.cpp
@@ -0,0 +1,160 @@
+/*
+ * Copyright (C) 2015 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_NDEBUG 0
+#define LOG_TAG "Metadata"
+#include <cutils/log.h>
+
+#include <system/camera_metadata.h>
+
+#define ATRACE_TAG (ATRACE_TAG_CAMERA | ATRACE_TAG_HAL)
+#include <utils/Trace.h>
+
+#include "Metadata.h"
+
+namespace usb_camera_hal {
+
+Metadata::Metadata():
+    mData(NULL) {
+}
+
+Metadata::~Metadata() {
+    replace(NULL);
+}
+
+void Metadata::replace(camera_metadata_t *m) {
+    if (m == mData) {
+        return;
+    }
+    if (mData)
+        free_camera_metadata(mData);
+    mData = m;
+}
+
+int Metadata::init(const camera_metadata_t *metadata) {
+    camera_metadata_t* tmp;
+
+    if (!validate_camera_metadata_structure(metadata, NULL))
+        return -EINVAL;
+
+    tmp = clone_camera_metadata(metadata);
+    if (tmp == NULL)
+        return -EINVAL;
+
+    replace(tmp);
+    return 0;
+}
+
+int Metadata::addUInt8(uint32_t tag, int count, const uint8_t *data) {
+    if (!validate(tag, TYPE_BYTE, count)) return -EINVAL;
+    return add(tag, count, data);
+}
+
+int Metadata::add1UInt8(uint32_t tag, const uint8_t data) {
+    return addUInt8(tag, 1, &data);
+}
+
+int Metadata::addInt32(uint32_t tag, int count, const int32_t *data) {
+    if (!validate(tag, TYPE_INT32, count)) return -EINVAL;
+    return add(tag, count, data);
+}
+
+int Metadata::addFloat(uint32_t tag, int count, const float *data) {
+    if (!validate(tag, TYPE_FLOAT, count)) return -EINVAL;
+    return add(tag, count, data);
+}
+
+int Metadata::addInt64(uint32_t tag, int count, const int64_t *data) {
+    if (!validate(tag, TYPE_INT64, count)) return -EINVAL;
+    return add(tag, count, data);
+}
+
+int Metadata::addDouble(uint32_t tag, int count, const double *data) {
+    if (!validate(tag, TYPE_DOUBLE, count)) return -EINVAL;
+    return add(tag, count, data);
+}
+
+int Metadata::addRational(uint32_t tag, int count,
+        const camera_metadata_rational_t *data) {
+    if (!validate(tag, TYPE_RATIONAL, count)) return -EINVAL;
+    return add(tag, count, data);
+}
+
+bool Metadata::validate(uint32_t tag, int tag_type, int count) {
+    if (get_camera_metadata_tag_type(tag) < 0) {
+        ALOGE("%s: Invalid metadata entry tag: %d", __func__, tag);
+        return false;
+    }
+    if (tag_type < 0 || tag_type >= NUM_TYPES) {
+        ALOGE("%s: Invalid metadata entry tag type: %d", __func__, tag_type);
+        return false;
+    }
+    if (tag_type != get_camera_metadata_tag_type(tag)) {
+        ALOGE("%s: Tag %d called with incorrect type: %s(%d)", __func__, tag,
+                camera_metadata_type_names[tag_type], tag_type);
+        return false;
+    }
+    if (count < 1) {
+        ALOGE("%s: Invalid metadata entry count: %d", __func__, count);
+        return false;
+    }
+    return true;
+}
+
+int Metadata::add(uint32_t tag, int count, const void *tag_data) {
+    // Opportunistically attempt to add if metadata has room for it
+    if (!add_camera_metadata_entry(mData, tag, tag_data, count)) {
+        return 0;
+    }
+
+    int res;
+    camera_metadata_t* tmp;
+    int tag_type = get_camera_metadata_tag_type(tag);
+    size_t size = calculate_camera_metadata_entry_data_size(tag_type, count);
+    size_t entry_capacity = get_camera_metadata_entry_count(mData) + 1;
+    size_t data_capacity = get_camera_metadata_data_count(mData) + size;
+
+    // Double new dimensions to minimize future reallocations
+    tmp = allocate_camera_metadata(entry_capacity * 2, data_capacity * 2);
+    if (tmp == NULL) {
+        ALOGE("%s: Failed to allocate new metadata with %zu entries, %zu data",
+                __func__, entry_capacity, data_capacity);
+        return -ENOMEM;
+    }
+    // Append the current metadata to the new (empty) metadata
+    res = append_camera_metadata(tmp, mData);
+    if (res) {
+        ALOGE("%s: Failed to append old metadata %p to new %p",
+                __func__, mData, tmp);
+        return res;
+    }
+    // Add the remaining new item
+    res = add_camera_metadata_entry(tmp, tag, tag_data, count);
+    if (res) {
+        ALOGE("%s: Failed to add new entry (%d, %p, %d) to metadata %p",
+                __func__, tag, tag_data, count, tmp);
+        return res;
+    }
+
+    replace(tmp);
+    return 0;
+}
+
+camera_metadata_t* Metadata::get() {
+    return mData;
+}
+
+} // namespace usb_camera_hal
diff --git a/modules/usbcamera/Metadata.h b/modules/usbcamera/Metadata.h
new file mode 100644
index 0000000..288db16
--- /dev/null
+++ b/modules/usbcamera/Metadata.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2015 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 METADATA_H_
+#define METADATA_H_
+
+#include <stdint.h>
+#include <hardware/camera3.h>
+#include <system/camera_metadata.h>
+
+namespace usb_camera_hal {
+// Metadata is a convenience class for dealing with libcamera_metadata
+class Metadata {
+    public:
+        Metadata();
+        ~Metadata();
+        // Initialize with framework metadata
+        int init(const camera_metadata_t *metadata);
+
+        // Parse and add an entry. Allocates and copies new storage for *data.
+        int addUInt8(uint32_t tag, int count, const uint8_t *data);
+        int add1UInt8(uint32_t tag, const uint8_t data);
+        int addInt32(uint32_t tag, int count, const int32_t *data);
+        int addFloat(uint32_t tag, int count, const float *data);
+        int addInt64(uint32_t tag, int count, const int64_t *data);
+        int addDouble(uint32_t tag, int count, const double *data);
+        int addRational(uint32_t tag, int count,
+                const camera_metadata_rational_t *data);
+
+        // Get a handle to the current metadata
+        // This is not a durable handle, and may be destroyed by add*/init
+        camera_metadata_t* get();
+
+    private:
+        // Actual internal storage
+        camera_metadata_t* mData;
+        // Destroy old metadata and replace with new
+        void replace(camera_metadata_t *m);
+        // Validate the tag, type and count for a metadata entry
+        bool validate(uint32_t tag, int tag_type, int count);
+        // Add a verified tag with data
+        int add(uint32_t tag, int count, const void *tag_data);
+};
+} // namespace usb_camera_hal
+
+#endif // METADATA_H_
diff --git a/modules/usbcamera/Stream.cpp b/modules/usbcamera/Stream.cpp
new file mode 100644
index 0000000..a3fefa3
--- /dev/null
+++ b/modules/usbcamera/Stream.cpp
@@ -0,0 +1,182 @@
+/*
+ * Copyright (C) 2015 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_NDEBUG 0
+#define LOG_TAG "Stream"
+#include <cutils/log.h>
+
+#include <stdio.h>
+#include <hardware/camera3.h>
+#include <hardware/gralloc.h>
+#include <system/graphics.h>
+#include <utils/Mutex.h>
+
+#define ATRACE_TAG (ATRACE_TAG_CAMERA | ATRACE_TAG_HAL)
+#include <utils/Trace.h>
+
+#include "Stream.h"
+
+namespace usb_camera_hal {
+
+Stream::Stream(int id, camera3_stream_t *s)
+  : mReuse(false),
+    mId(id),
+    mStream(s){
+}
+
+Stream::~Stream() {
+    for (size_t i = 0; i < mBuffers.size(); i++) {
+        delete mBuffers[i];
+    }
+
+    mBuffers.clear();
+}
+
+void Stream::setUsage(uint32_t usage) {
+    android::Mutex::Autolock al(mLock);
+    if (usage != mStream->usage) {
+        mStream->usage = usage;
+    }
+}
+
+void Stream::setMaxBuffers(uint32_t max_buffers) {
+    android::Mutex::Autolock al(mLock);
+    if (max_buffers != mStream->max_buffers) {
+        mStream->max_buffers = max_buffers;
+    }
+}
+
+int Stream::getType() {
+    return mStream->stream_type;
+}
+
+bool Stream::isInputType() {
+    return mStream->stream_type == CAMERA3_STREAM_INPUT ||
+            mStream->stream_type == CAMERA3_STREAM_BIDIRECTIONAL;
+}
+
+bool Stream::isOutputType() {
+    return mStream->stream_type == CAMERA3_STREAM_OUTPUT ||
+            mStream->stream_type == CAMERA3_STREAM_BIDIRECTIONAL;
+}
+
+const char* Stream::typeToString(int type) {
+    switch (type) {
+    case CAMERA3_STREAM_INPUT:
+        return "CAMERA3_STREAM_INPUT";
+    case CAMERA3_STREAM_OUTPUT:
+        return "CAMERA3_STREAM_OUTPUT";
+    case CAMERA3_STREAM_BIDIRECTIONAL:
+        return "CAMERA3_STREAM_BIDIRECTIONAL";
+    }
+    return "Invalid stream type!";
+}
+
+const char* Stream::formatToString(int format) {
+    // See <system/graphics.h> for full list
+    switch (format) {
+    case HAL_PIXEL_FORMAT_BGRA_8888:
+        return "BGRA 8888";
+    case HAL_PIXEL_FORMAT_RGBA_8888:
+        return "RGBA 8888";
+    case HAL_PIXEL_FORMAT_RGBX_8888:
+        return "RGBX 8888";
+    case HAL_PIXEL_FORMAT_RGB_888:
+        return "RGB 888";
+    case HAL_PIXEL_FORMAT_RGB_565:
+        return "RGB 565";
+    case HAL_PIXEL_FORMAT_sRGB_A_8888:
+        return "sRGB A 8888";
+    case HAL_PIXEL_FORMAT_sRGB_X_8888:
+        return "sRGB B 8888";
+    case HAL_PIXEL_FORMAT_Y8:
+        return "Y8";
+    case HAL_PIXEL_FORMAT_Y16:
+        return "Y16";
+    case HAL_PIXEL_FORMAT_YV12:
+        return "YV12";
+    case HAL_PIXEL_FORMAT_YCbCr_422_SP:
+        return "NV16";
+    case HAL_PIXEL_FORMAT_YCrCb_420_SP:
+        return "NV21";
+    case HAL_PIXEL_FORMAT_YCbCr_422_I:
+        return "YUY2";
+    case HAL_PIXEL_FORMAT_RAW_SENSOR:
+        return "RAW SENSOR";
+    case HAL_PIXEL_FORMAT_BLOB:
+        return "BLOB";
+    case HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED:
+        return "IMPLEMENTATION DEFINED";
+    case HAL_PIXEL_FORMAT_YCbCr_420_888:
+        return "FLEXIBLE YCbCr 420 888";
+    }
+    return "Invalid stream format!";
+}
+
+bool Stream::isValidReuseStream(int id, camera3_stream_t *s) {
+    if (id != mId) {
+        ALOGE("%s:%d: Invalid camera id for reuse. Got %d expect %d",
+                __func__, mId, id, mId);
+        return false;
+    }
+    if (s != mStream) {
+        ALOGE("%s:%d: Invalid stream handle for reuse. Got %p expect %p",
+                __func__, mId, s, mStream);
+        return false;
+    }
+    if (s->stream_type != mStream->stream_type) {
+        ALOGE("%s:%d: Mismatched type in reused stream. Got %s(%d) "
+                "expect %s(%d)", __func__, mId, typeToString(s->stream_type),
+                s->stream_type, typeToString(mStream->stream_type), mStream->stream_type);
+        return false;
+    }
+    if (s->format != mStream->format) {
+        ALOGE("%s:%d: Mismatched format in reused stream. Got %s(%d) "
+                "expect %s(%d)", __func__, mId, formatToString(s->format),
+                s->format, formatToString(mStream->format), mStream->format);
+        return false;
+    }
+    if (s->width != mStream->width) {
+        ALOGE("%s:%d: Mismatched width in reused stream. Got %d expect %d",
+                __func__, mId, s->width, mStream->width);
+        return false;
+    }
+    if (s->height != mStream->height) {
+        ALOGE("%s:%d: Mismatched height in reused stream. Got %d expect %d",
+                __func__, mId, s->height, mStream->height);
+        return false;
+    }
+    return true;
+}
+
+void Stream::dump(int fd) {
+    android::Mutex::Autolock al(mLock);
+
+    dprintf(fd, "Stream ID: %d (%p)\n", mId, mStream);
+    dprintf(fd, "Stream Type: %s (%d)\n", typeToString(mStream->stream_type), mStream->stream_type);
+    dprintf(fd, "Width: %" PRIu32 " Height: %" PRIu32 "\n", mStream->width, mStream->height);
+    dprintf(fd, "Stream Format: %s (%d)", formatToString(mStream->format), mStream->format);
+    // ToDo: prettyprint usage mask flags
+    dprintf(fd, "Gralloc Usage Mask: %#" PRIx32 "\n", mStream->usage);
+    dprintf(fd, "Max Buffer Count: %" PRIu32 "\n", mStream->max_buffers);
+    dprintf(fd, "Number of Buffers in use by HAL: %" PRIu32 "\n", mBuffers.size());
+    for (size_t i = 0; i < mBuffers.size(); i++) {
+        dprintf(fd, "Buffer %" PRIu32 "/%" PRIu32 ": %p\n", i, mBuffers.size(),
+                mBuffers[i]);
+    }
+}
+
+} // namespace usb_camera_hal
diff --git a/modules/usbcamera/Stream.h b/modules/usbcamera/Stream.h
new file mode 100644
index 0000000..022ca9f
--- /dev/null
+++ b/modules/usbcamera/Stream.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2015 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 STREAM_H_
+#define STREAM_H_
+
+#include <hardware/camera3.h>
+#include <hardware/gralloc.h>
+#include <system/graphics.h>
+#include <utils/Mutex.h>
+#include <utils/Vector.h>
+
+namespace usb_camera_hal {
+// Stream represents a single input or output stream for a camera device.
+class Stream {
+    public:
+        Stream(int id, camera3_stream_t *s);
+        ~Stream();
+
+        // validate that a stream's parameters match this stream's parameters
+        bool isValidReuseStream(int id, camera3_stream_t *s);
+
+        void setUsage(uint32_t usage);
+        void setMaxBuffers(uint32_t max_buffers);
+
+        int getType();
+        bool isInputType();
+        bool isOutputType();
+        const char* typeToString(int type);
+        const char* formatToString(int format);
+        void dump(int fd);
+
+        // This stream is being reused. Used in stream configuration passes
+        bool mReuse;
+
+    private:
+        // The camera device id this stream belongs to
+        const int mId;
+        // Handle to framework's stream, used as a cookie for buffers
+        camera3_stream_t *mStream;
+        // Array of handles to buffers currently in use by the stream
+        android::Vector<buffer_handle_t *> mBuffers;
+        // Lock protecting the Stream object for modifications
+        android::Mutex mLock;
+};
+} // namespace usb_camera_hal
+
+#endif // STREAM_H_
diff --git a/modules/usbcamera/UsbCamera.cpp b/modules/usbcamera/UsbCamera.cpp
new file mode 100644
index 0000000..ded3e92
--- /dev/null
+++ b/modules/usbcamera/UsbCamera.cpp
@@ -0,0 +1,321 @@
+/*
+ * Copyright (C) 2015 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_NDEBUG 0
+#define LOG_TAG "UsbCameraDevice"
+#include <cutils/log.h>
+
+#include <system/camera_metadata.h>
+
+#define ATRACE_TAG (ATRACE_TAG_CAMERA | ATRACE_TAG_HAL)
+#include <utils/Trace.h>
+
+#include "Camera.h"
+#include "UsbCamera.h"
+
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
+
+namespace usb_camera_hal {
+
+UsbCamera::UsbCamera(int id) : Camera(id) {
+}
+
+UsbCamera::~UsbCamera() {
+}
+
+int UsbCamera::initStaticInfo() {
+    /*
+     * Setup static camera info.  This will have to customized per camera
+     * device.
+     * TODO: this is just some sample code, need tailor for USB cameras.
+     */
+    if (mStaticInfo != NULL) {
+        free_camera_metadata(mStaticInfo);
+    }
+
+    Metadata m;
+
+    /* android.control */
+    int32_t android_control_ae_available_target_fps_ranges[] = {30, 30};
+    m.addInt32(ANDROID_CONTROL_AE_AVAILABLE_TARGET_FPS_RANGES,
+            ARRAY_SIZE(android_control_ae_available_target_fps_ranges),
+            android_control_ae_available_target_fps_ranges);
+
+    int32_t android_control_ae_compensation_range[] = {-4, 4};
+    m.addInt32(ANDROID_CONTROL_AE_COMPENSATION_RANGE,
+            ARRAY_SIZE(android_control_ae_compensation_range),
+            android_control_ae_compensation_range);
+
+    camera_metadata_rational_t android_control_ae_compensation_step[] = {{2,1}};
+    m.addRational(ANDROID_CONTROL_AE_COMPENSATION_STEP,
+            ARRAY_SIZE(android_control_ae_compensation_step),
+            android_control_ae_compensation_step);
+
+    int32_t android_control_max_regions[] = {/*AE*/ 1,/*AWB*/ 1,/*AF*/ 1};
+    m.addInt32(ANDROID_CONTROL_MAX_REGIONS,
+            ARRAY_SIZE(android_control_max_regions),
+            android_control_max_regions);
+
+    /* android.jpeg */
+    int32_t android_jpeg_available_thumbnail_sizes[] = {0, 0, 128, 96};
+    m.addInt32(ANDROID_JPEG_AVAILABLE_THUMBNAIL_SIZES,
+            ARRAY_SIZE(android_jpeg_available_thumbnail_sizes),
+            android_jpeg_available_thumbnail_sizes);
+
+    int32_t android_jpeg_max_size[] = {13 * 1024 * 1024}; // 13MB
+    m.addInt32(ANDROID_JPEG_MAX_SIZE,
+            ARRAY_SIZE(android_jpeg_max_size),
+            android_jpeg_max_size);
+
+    /* android.lens */
+    float android_lens_info_available_focal_lengths[] = {1.0};
+    m.addFloat(ANDROID_LENS_INFO_AVAILABLE_FOCAL_LENGTHS,
+            ARRAY_SIZE(android_lens_info_available_focal_lengths),
+            android_lens_info_available_focal_lengths);
+
+    /* android.request */
+    int32_t android_request_max_num_output_streams[] = {0, 3, 1};
+    m.addInt32(ANDROID_REQUEST_MAX_NUM_OUTPUT_STREAMS,
+            ARRAY_SIZE(android_request_max_num_output_streams),
+            android_request_max_num_output_streams);
+
+    /* android.scaler */
+    int32_t android_scaler_available_formats[] = {
+            HAL_PIXEL_FORMAT_RAW_SENSOR,
+            HAL_PIXEL_FORMAT_BLOB,
+            HAL_PIXEL_FORMAT_RGBA_8888,
+            HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED,
+            // These are handled by YCbCr_420_888
+            //        HAL_PIXEL_FORMAT_YV12,
+            //        HAL_PIXEL_FORMAT_YCrCb_420_SP,
+            HAL_PIXEL_FORMAT_YCbCr_420_888};
+    m.addInt32(ANDROID_SCALER_AVAILABLE_FORMATS,
+            ARRAY_SIZE(android_scaler_available_formats),
+            android_scaler_available_formats);
+
+    int64_t android_scaler_available_jpeg_min_durations[] = {1};
+    m.addInt64(ANDROID_SCALER_AVAILABLE_JPEG_MIN_DURATIONS,
+            ARRAY_SIZE(android_scaler_available_jpeg_min_durations),
+            android_scaler_available_jpeg_min_durations);
+
+    int32_t android_scaler_available_jpeg_sizes[] = {640, 480};
+    m.addInt32(ANDROID_SCALER_AVAILABLE_JPEG_SIZES,
+            ARRAY_SIZE(android_scaler_available_jpeg_sizes),
+            android_scaler_available_jpeg_sizes);
+
+    float android_scaler_available_max_digital_zoom[] = {1};
+    m.addFloat(ANDROID_SCALER_AVAILABLE_MAX_DIGITAL_ZOOM,
+            ARRAY_SIZE(android_scaler_available_max_digital_zoom),
+            android_scaler_available_max_digital_zoom);
+
+    int64_t android_scaler_available_processed_min_durations[] = {1};
+    m.addInt64(ANDROID_SCALER_AVAILABLE_PROCESSED_MIN_DURATIONS,
+            ARRAY_SIZE(android_scaler_available_processed_min_durations),
+            android_scaler_available_processed_min_durations);
+
+    int32_t android_scaler_available_processed_sizes[] = {640, 480};
+    m.addInt32(ANDROID_SCALER_AVAILABLE_PROCESSED_SIZES,
+            ARRAY_SIZE(android_scaler_available_processed_sizes),
+            android_scaler_available_processed_sizes);
+
+    int64_t android_scaler_available_raw_min_durations[] = {1};
+    m.addInt64(ANDROID_SCALER_AVAILABLE_RAW_MIN_DURATIONS,
+            ARRAY_SIZE(android_scaler_available_raw_min_durations),
+            android_scaler_available_raw_min_durations);
+
+    int32_t android_scaler_available_raw_sizes[] = {640, 480};
+    m.addInt32(ANDROID_SCALER_AVAILABLE_RAW_SIZES,
+            ARRAY_SIZE(android_scaler_available_raw_sizes),
+            android_scaler_available_raw_sizes);
+
+    /* android.sensor */
+
+    int32_t android_sensor_info_active_array_size[] = {0, 0, 640, 480};
+    m.addInt32(ANDROID_SENSOR_INFO_ACTIVE_ARRAY_SIZE,
+            ARRAY_SIZE(android_sensor_info_active_array_size),
+            android_sensor_info_active_array_size);
+
+    int32_t android_sensor_info_sensitivity_range[] =
+            {100, 1600};
+    m.addInt32(ANDROID_SENSOR_INFO_SENSITIVITY_RANGE,
+            ARRAY_SIZE(android_sensor_info_sensitivity_range),
+            android_sensor_info_sensitivity_range);
+
+    int64_t android_sensor_info_max_frame_duration[] = {30000000000};
+    m.addInt64(ANDROID_SENSOR_INFO_MAX_FRAME_DURATION,
+            ARRAY_SIZE(android_sensor_info_max_frame_duration),
+            android_sensor_info_max_frame_duration);
+
+    float android_sensor_info_physical_size[] = {3.2, 2.4};
+    m.addFloat(ANDROID_SENSOR_INFO_PHYSICAL_SIZE,
+            ARRAY_SIZE(android_sensor_info_physical_size),
+            android_sensor_info_physical_size);
+
+    int32_t android_sensor_info_pixel_array_size[] = {640, 480};
+    m.addInt32(ANDROID_SENSOR_INFO_PIXEL_ARRAY_SIZE,
+            ARRAY_SIZE(android_sensor_info_pixel_array_size),
+            android_sensor_info_pixel_array_size);
+
+    int32_t android_sensor_orientation[] = {0};
+    m.addInt32(ANDROID_SENSOR_ORIENTATION,
+            ARRAY_SIZE(android_sensor_orientation),
+            android_sensor_orientation);
+
+    /* End of static camera characteristics */
+
+    mStaticInfo = clone_camera_metadata(m.get());
+
+    return 0;
+}
+
+int UsbCamera::openDevice() {
+    // TODO: implement usb camera device open sequence: open device nodes etc.
+
+    return 0;
+}
+
+int UsbCamera::closeDevice() {
+    // TODO: implement usb camera device close sequence: close device nodes etc.
+
+    return 0;
+}
+
+int UsbCamera::processCaptureBuffer(const camera3_stream_buffer_t *in,
+        camera3_stream_buffer_t *out) {
+    if (in->acquire_fence != -1) {
+        int res = sync_wait(in->acquire_fence, CAMERA_SYNC_TIMEOUT_MS);
+        if (res == -ETIME) {
+            ALOGE("%s:%d: Timeout waiting on buffer acquire fence",
+                    __func__, mId);
+            return res;
+        } else if (res) {
+            ALOGE("%s:%d: Error waiting on buffer acquire fence: %s(%d)",
+                    __func__, mId, strerror(-res), res);
+            return res;
+        }
+    }
+
+    out->stream = in->stream;
+    out->buffer = in->buffer;
+    out->status = CAMERA3_BUFFER_STATUS_OK;
+    // TODO: use driver-backed release fences
+    out->acquire_fence = -1;
+    out->release_fence = -1;
+
+    // TODO: lock and software-paint buffer
+    return 0;
+}
+
+int UsbCamera::initDevice() {
+    int res;
+    Metadata base;
+
+    // Create standard settings templates from copies of base metadata
+    res = base.add1UInt8(ANDROID_CONTROL_MODE, ANDROID_CONTROL_MODE_OFF);
+    if (res)
+        return res;
+
+    // Use base settings to create all other templates and set them. This is just some samples,
+    // More initialization may be needed.
+    res = initPreviewTemplate(base);
+    if (res)
+        return res;
+    res = initStillTemplate(base);
+    if (res)
+        return res;
+    res = initRecordTemplate(base);
+    if (res)
+        return res;
+    res = initSnapshotTemplate(base);
+    if (res)
+        return res;
+    res = initZslTemplate(base);
+    if (res)
+        return res;
+    res = initManualTemplate(base);
+    if (res)
+        return res;
+
+    return 0;
+}
+
+int UsbCamera::initPreviewTemplate(Metadata m) {
+    // Setup default preview controls
+    int res = m.add1UInt8(ANDROID_CONTROL_CAPTURE_INTENT,
+                            ANDROID_CONTROL_CAPTURE_INTENT_PREVIEW);
+
+    if (res)
+        return res;
+    // TODO: set fast auto-focus, auto-whitebalance, auto-exposure, auto flash
+    return setTemplate(CAMERA3_TEMPLATE_PREVIEW, m.get());
+}
+
+int UsbCamera::initStillTemplate(Metadata m) {
+    int res = m.add1UInt8(ANDROID_CONTROL_CAPTURE_INTENT,
+                            ANDROID_CONTROL_CAPTURE_INTENT_STILL_CAPTURE);
+    // Setup default still capture controls
+    if (res)
+        return res;
+    // TODO: set fast auto-focus, auto-whitebalance, auto-exposure, auto flash
+    return setTemplate(CAMERA3_TEMPLATE_STILL_CAPTURE, m.get());
+}
+
+int UsbCamera::initRecordTemplate(Metadata m) {
+    int res = m.add1UInt8(ANDROID_CONTROL_CAPTURE_INTENT,
+                            ANDROID_CONTROL_CAPTURE_INTENT_VIDEO_RECORD);
+    // Setup default video record controls
+    if (res)
+        return res;
+    // TODO: set slow auto-focus, auto-whitebalance, auto-exposure, flash off
+    return setTemplate(CAMERA3_TEMPLATE_VIDEO_RECORD, m.get());
+}
+
+int UsbCamera::initSnapshotTemplate(Metadata m) {
+    int res = m.add1UInt8(ANDROID_CONTROL_CAPTURE_INTENT,
+                            ANDROID_CONTROL_CAPTURE_INTENT_VIDEO_SNAPSHOT);
+    // Setup default video snapshot controls
+    if (res)
+        return res;
+    // TODO: set slow auto-focus, auto-whitebalance, auto-exposure, flash off
+    return setTemplate(CAMERA3_TEMPLATE_VIDEO_SNAPSHOT, m.get());
+}
+
+int UsbCamera::initZslTemplate(Metadata m) {
+    int res = m.add1UInt8(ANDROID_CONTROL_CAPTURE_INTENT,
+                            ANDROID_CONTROL_CAPTURE_INTENT_ZERO_SHUTTER_LAG);
+    // Setup default zero shutter lag controls
+    if (res)
+        return res;
+    // TODO: set reprocessing parameters for zsl input queue
+    return setTemplate(CAMERA3_TEMPLATE_ZERO_SHUTTER_LAG, m.get());
+}
+
+int UsbCamera::initManualTemplate(Metadata m) {
+    int res = m.add1UInt8(ANDROID_CONTROL_CAPTURE_INTENT,
+                            ANDROID_CONTROL_CAPTURE_INTENT_MANUAL);
+    // Setup manual controls
+    if (res)
+        return res;
+    // TODO: set reprocessing parameters for zsl input queue
+    return setTemplate(CAMERA3_TEMPLATE_MANUAL, m.get());
+}
+
+bool UsbCamera::isValidCaptureSettings(const camera_metadata_t* settings) {
+    // TODO: reject settings that cannot be captured
+    return true;
+}
+
+} // namespace usb_camera_hal
diff --git a/modules/usbcamera/UsbCamera.h b/modules/usbcamera/UsbCamera.h
new file mode 100644
index 0000000..fe52ade
--- /dev/null
+++ b/modules/usbcamera/UsbCamera.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2015 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 EXAMPLE_CAMERA_H_
+#define EXAMPLE_CAMERA_H_
+
+#include <system/camera_metadata.h>
+#include "Camera.h"
+
+namespace usb_camera_hal {
+/**
+ * UsbCamera is an example for a specific camera device. The Camera instance contains
+ * a specific camera device (e.g. UsbCamera) holds all specific metadata and logic about
+ * that device.
+ */
+class UsbCamera : public Camera {
+    public:
+        UsbCamera(int id);
+        ~UsbCamera();
+
+    private:
+        // Initialize static camera characteristics for individual device
+        int initStaticInfo();
+        int openDevice();
+        // Initialize whole device (templates/etc) when opened
+        int initDevice();
+        int flushDevice();
+        int closeDevice();
+        int processCaptureBuffer(const camera3_stream_buffer_t *in, camera3_stream_buffer_t *out);
+        // Initialize each template metadata controls
+        int initPreviewTemplate(Metadata m);
+        int initStillTemplate(Metadata m);
+        int initRecordTemplate(Metadata m);
+        int initSnapshotTemplate(Metadata m);
+        int initZslTemplate(Metadata m);
+        int initManualTemplate(Metadata m);
+        // Verify settings are valid for a capture with this device
+        bool isValidCaptureSettings(const camera_metadata_t* settings);
+};
+} // namespace usb_camera_hal
+
+#endif // CAMERA_H_