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      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ANDROID_INCLUDE_CAMERA3_H
     18 #define ANDROID_INCLUDE_CAMERA3_H
     19 
     20 #include <system/camera_metadata.h>
     21 #include "camera_common.h"
     22 
     23 /**
     24  * Camera device HAL 3.2 [ CAMERA_DEVICE_API_VERSION_3_2 ]
     25  *
     26  * This is the current recommended version of the camera device HAL.
     27  *
     28  * Supports the android.hardware.Camera API, and as of v3.2, the
     29  * android.hardware.camera2 API in LIMITED or FULL modes.
     30  *
     31  * Camera devices that support this version of the HAL must return
     32  * CAMERA_DEVICE_API_VERSION_3_2 in camera_device_t.common.version and in
     33  * camera_info_t.device_version (from camera_module_t.get_camera_info).
     34  *
     35  * CAMERA_DEVICE_API_VERSION_3_2:
     36  *    Camera modules that may contain version 3.2 devices must implement at
     37  *    least version 2.2 of the camera module interface (as defined by
     38  *    camera_module_t.common.module_api_version).
     39  *
     40  * <= CAMERA_DEVICE_API_VERSION_3_1:
     41  *    Camera modules that may contain version 3.1 (or 3.0) devices must
     42  *    implement at least version 2.0 of the camera module interface
     43  *    (as defined by camera_module_t.common.module_api_version).
     44  *
     45  * See camera_common.h for more versioning details.
     46  *
     47  * Documentation index:
     48  *   S1. Version history
     49  *   S2. Startup and operation sequencing
     50  *   S3. Operational modes
     51  *   S4. 3A modes and state machines
     52  *   S5. Cropping
     53  *   S6. Error management
     54  *   S7. Key Performance Indicator (KPI) glossary
     55  *   S8. Sample Use Cases
     56  *   S9. Notes on Controls and Metadata
     57  */
     58 
     59 /**
     60  * S1. Version history:
     61  *
     62  * 1.0: Initial Android camera HAL (Android 4.0) [camera.h]:
     63  *
     64  *   - Converted from C++ CameraHardwareInterface abstraction layer.
     65  *
     66  *   - Supports android.hardware.Camera API.
     67  *
     68  * 2.0: Initial release of expanded-capability HAL (Android 4.2) [camera2.h]:
     69  *
     70  *   - Sufficient for implementing existing android.hardware.Camera API.
     71  *
     72  *   - Allows for ZSL queue in camera service layer
     73  *
     74  *   - Not tested for any new features such manual capture control, Bayer RAW
     75  *     capture, reprocessing of RAW data.
     76  *
     77  * 3.0: First revision of expanded-capability HAL:
     78  *
     79  *   - Major version change since the ABI is completely different. No change to
     80  *     the required hardware capabilities or operational model from 2.0.
     81  *
     82  *   - Reworked input request and stream queue interfaces: Framework calls into
     83  *     HAL with next request and stream buffers already dequeued. Sync framework
     84  *     support is included, necessary for efficient implementations.
     85  *
     86  *   - Moved triggers into requests, most notifications into results.
     87  *
     88  *   - Consolidated all callbacks into framework into one structure, and all
     89  *     setup methods into a single initialize() call.
     90  *
     91  *   - Made stream configuration into a single call to simplify stream
     92  *     management. Bidirectional streams replace STREAM_FROM_STREAM construct.
     93  *
     94  *   - Limited mode semantics for older/limited hardware devices.
     95  *
     96  * 3.1: Minor revision of expanded-capability HAL:
     97  *
     98  *   - configure_streams passes consumer usage flags to the HAL.
     99  *
    100  *   - flush call to drop all in-flight requests/buffers as fast as possible.
    101  *
    102  * 3.2: Minor revision of expanded-capability HAL:
    103  *
    104  *   - Deprecates get_metadata_vendor_tag_ops.  Please use get_vendor_tag_ops
    105  *     in camera_common.h instead.
    106  *
    107  *   - register_stream_buffers deprecated. All gralloc buffers provided
    108  *     by framework to HAL in process_capture_request may be new at any time.
    109  *
    110  *   - add partial result support. process_capture_result may be called
    111  *     multiple times with a subset of the available result before the full
    112  *     result is available.
    113  *
    114  *   - add manual template to camera3_request_template. The applications may
    115  *     use this template to control the capture settings directly.
    116  *
    117  *   - Rework the bidirectional and input stream specifications.
    118  *
    119  *   - change the input buffer return path. The buffer is returned in
    120  *     process_capture_result instead of process_capture_request.
    121  *
    122  */
    123 
    124 /**
    125  * S2. Startup and general expected operation sequence:
    126  *
    127  * 1. Framework calls camera_module_t->common.open(), which returns a
    128  *    hardware_device_t structure.
    129  *
    130  * 2. Framework inspects the hardware_device_t->version field, and instantiates
    131  *    the appropriate handler for that version of the camera hardware device. In
    132  *    case the version is CAMERA_DEVICE_API_VERSION_3_0, the device is cast to
    133  *    a camera3_device_t.
    134  *
    135  * 3. Framework calls camera3_device_t->ops->initialize() with the framework
    136  *    callback function pointers. This will only be called this one time after
    137  *    open(), before any other functions in the ops structure are called.
    138  *
    139  * 4. The framework calls camera3_device_t->ops->configure_streams() with a list
    140  *    of input/output streams to the HAL device.
    141  *
    142  * 5. <= CAMERA_DEVICE_API_VERSION_3_1:
    143  *
    144  *    The framework allocates gralloc buffers and calls
    145  *    camera3_device_t->ops->register_stream_buffers() for at least one of the
    146  *    output streams listed in configure_streams. The same stream is registered
    147  *    only once.
    148  *
    149  *    >= CAMERA_DEVICE_API_VERSION_3_2:
    150  *
    151  *    camera3_device_t->ops->register_stream_buffers() is not called and must
    152  *    be NULL.
    153  *
    154  * 6. The framework requests default settings for some number of use cases with
    155  *    calls to camera3_device_t->ops->construct_default_request_settings(). This
    156  *    may occur any time after step 3.
    157  *
    158  * 7. The framework constructs and sends the first capture request to the HAL,
    159  *    with settings based on one of the sets of default settings, and with at
    160  *    least one output stream, which has been registered earlier by the
    161  *    framework. This is sent to the HAL with
    162  *    camera3_device_t->ops->process_capture_request(). The HAL must block the
    163  *    return of this call until it is ready for the next request to be sent.
    164  *
    165  *    >= CAMERA_DEVICE_API_VERSION_3_2:
    166  *
    167  *    The buffer_handle_t provided in the camera3_stream_buffer_t array
    168  *    in the camera3_capture_request_t may be new and never-before-seen
    169  *    by the HAL on any given new request.
    170  *
    171  * 8. The framework continues to submit requests, and call
    172  *    construct_default_request_settings to get default settings buffers for
    173  *    other use cases.
    174  *
    175  *    <= CAMERA_DEVICE_API_VERSION_3_1:
    176  *
    177  *    The framework may call register_stream_buffers() at this time for
    178  *    not-yet-registered streams.
    179  *
    180  * 9. When the capture of a request begins (sensor starts exposing for the
    181  *    capture), the HAL calls camera3_callback_ops_t->notify() with the SHUTTER
    182  *    event, including the frame number and the timestamp for start of exposure.
    183  *
    184  *    <= CAMERA_DEVICE_API_VERSION_3_1:
    185  *
    186  *    This notify call must be made before the first call to
    187  *    process_capture_result() for that frame number.
    188  *
    189  *    >= CAMERA_DEVICE_API_VERSION_3_2:
    190  *
    191  *    The camera3_callback_ops_t->notify() call with the SHUTTER event should
    192  *    be made as early as possible since the framework will be unable to
    193  *    deliver gralloc buffers to the application layer (for that frame) until
    194  *    it has a valid timestamp for the start of exposure.
    195  *
    196  *    Both partial metadata results and the gralloc buffers may be sent to the
    197  *    framework at any time before or after the SHUTTER event.
    198  *
    199  * 10. After some pipeline delay, the HAL begins to return completed captures to
    200  *    the framework with camera3_callback_ops_t->process_capture_result(). These
    201  *    are returned in the same order as the requests were submitted. Multiple
    202  *    requests can be in flight at once, depending on the pipeline depth of the
    203  *    camera HAL device.
    204  *
    205  *    >= CAMERA_DEVICE_API_VERSION_3_2:
    206  *
    207  *    Once a buffer is returned by process_capture_result as part of the
    208  *    camera3_stream_buffer_t array, and the fence specified by release_fence
    209  *    has been signaled (this is a no-op for -1 fences), the ownership of that
    210  *    buffer is considered to be transferred back to the framework. After that,
    211  *    the HAL must no longer retain that particular buffer, and the
    212  *    framework may clean up the memory for it immediately.
    213  *
    214  *    process_capture_result may be called multiple times for a single frame,
    215  *    each time with a new disjoint piece of metadata and/or set of gralloc
    216  *    buffers. The framework will accumulate these partial metadata results
    217  *    into one result.
    218  *
    219  *    In particular, it is legal for a process_capture_result to be called
    220  *    simultaneously for both a frame N and a frame N+1 as long as the
    221  *    above rule holds for gralloc buffers (both input and output).
    222  *
    223  * 11. After some time, the framework may stop submitting new requests, wait for
    224  *    the existing captures to complete (all buffers filled, all results
    225  *    returned), and then call configure_streams() again. This resets the camera
    226  *    hardware and pipeline for a new set of input/output streams. Some streams
    227  *    may be reused from the previous configuration; if these streams' buffers
    228  *    had already been registered with the HAL, they will not be registered
    229  *    again. The framework then continues from step 7, if at least one
    230  *    registered output stream remains (otherwise, step 5 is required first).
    231  *
    232  * 12. Alternatively, the framework may call camera3_device_t->common->close()
    233  *    to end the camera session. This may be called at any time when no other
    234  *    calls from the framework are active, although the call may block until all
    235  *    in-flight captures have completed (all results returned, all buffers
    236  *    filled). After the close call returns, no more calls to the
    237  *    camera3_callback_ops_t functions are allowed from the HAL. Once the
    238  *    close() call is underway, the framework may not call any other HAL device
    239  *    functions.
    240  *
    241  * 13. In case of an error or other asynchronous event, the HAL must call
    242  *    camera3_callback_ops_t->notify() with the appropriate error/event
    243  *    message. After returning from a fatal device-wide error notification, the
    244  *    HAL should act as if close() had been called on it. However, the HAL must
    245  *    either cancel or complete all outstanding captures before calling
    246  *    notify(), so that once notify() is called with a fatal error, the
    247  *    framework will not receive further callbacks from the device. Methods
    248  *    besides close() should return -ENODEV or NULL after the notify() method
    249  *    returns from a fatal error message.
    250  */
    251 
    252 /**
    253  * S3. Operational modes:
    254  *
    255  * The camera 3 HAL device can implement one of two possible operational modes;
    256  * limited and full. Full support is expected from new higher-end
    257  * devices. Limited mode has hardware requirements roughly in line with those
    258  * for a camera HAL device v1 implementation, and is expected from older or
    259  * inexpensive devices. Full is a strict superset of limited, and they share the
    260  * same essential operational flow, as documented above.
    261  *
    262  * The HAL must indicate its level of support with the
    263  * android.info.supportedHardwareLevel static metadata entry, with 0 indicating
    264  * limited mode, and 1 indicating full mode support.
    265  *
    266  * Roughly speaking, limited-mode devices do not allow for application control
    267  * of capture settings (3A control only), high-rate capture of high-resolution
    268  * images, raw sensor readout, or support for YUV output streams above maximum
    269  * recording resolution (JPEG only for large images).
    270  *
    271  * ** Details of limited mode behavior:
    272  *
    273  * - Limited-mode devices do not need to implement accurate synchronization
    274  *   between capture request settings and the actual image data
    275  *   captured. Instead, changes to settings may take effect some time in the
    276  *   future, and possibly not for the same output frame for each settings
    277  *   entry. Rapid changes in settings may result in some settings never being
    278  *   used for a capture. However, captures that include high-resolution output
    279  *   buffers ( > 1080p ) have to use the settings as specified (but see below
    280  *   for processing rate).
    281  *
    282  * - Limited-mode devices do not need to support most of the
    283  *   settings/result/static info metadata. Specifically, only the following settings
    284  *   are expected to be consumed or produced by a limited-mode HAL device:
    285  *
    286  *   android.control.aeAntibandingMode (controls and dynamic)
    287  *   android.control.aeExposureCompensation (controls and dynamic)
    288  *   android.control.aeLock (controls and dynamic)
    289  *   android.control.aeMode (controls and dynamic)
    290  *   android.control.aeRegions (controls and dynamic)
    291  *   android.control.aeTargetFpsRange (controls and dynamic)
    292  *   android.control.aePrecaptureTrigger (controls and dynamic)
    293  *   android.control.afMode (controls and dynamic)
    294  *   android.control.afRegions (controls and dynamic)
    295  *   android.control.awbLock (controls and dynamic)
    296  *   android.control.awbMode (controls and dynamic)
    297  *   android.control.awbRegions (controls and dynamic)
    298  *   android.control.captureIntent (controls and dynamic)
    299  *   android.control.effectMode (controls and dynamic)
    300  *   android.control.mode (controls and dynamic)
    301  *   android.control.sceneMode (controls and dynamic)
    302  *   android.control.videoStabilizationMode (controls and dynamic)
    303  *   android.control.aeAvailableAntibandingModes (static)
    304  *   android.control.aeAvailableModes (static)
    305  *   android.control.aeAvailableTargetFpsRanges (static)
    306  *   android.control.aeCompensationRange (static)
    307  *   android.control.aeCompensationStep (static)
    308  *   android.control.afAvailableModes (static)
    309  *   android.control.availableEffects (static)
    310  *   android.control.availableSceneModes (static)
    311  *   android.control.availableVideoStabilizationModes (static)
    312  *   android.control.awbAvailableModes (static)
    313  *   android.control.maxRegions (static)
    314  *   android.control.sceneModeOverrides (static)
    315  *   android.control.aeState (dynamic)
    316  *   android.control.afState (dynamic)
    317  *   android.control.awbState (dynamic)
    318  *
    319  *   android.flash.mode (controls and dynamic)
    320  *   android.flash.info.available (static)
    321  *
    322  *   android.info.supportedHardwareLevel (static)
    323  *
    324  *   android.jpeg.gpsCoordinates (controls and dynamic)
    325  *   android.jpeg.gpsProcessingMethod (controls and dynamic)
    326  *   android.jpeg.gpsTimestamp (controls and dynamic)
    327  *   android.jpeg.orientation (controls and dynamic)
    328  *   android.jpeg.quality (controls and dynamic)
    329  *   android.jpeg.thumbnailQuality (controls and dynamic)
    330  *   android.jpeg.thumbnailSize (controls and dynamic)
    331  *   android.jpeg.availableThumbnailSizes (static)
    332  *   android.jpeg.maxSize (static)
    333  *
    334  *   android.lens.info.minimumFocusDistance (static)
    335  *
    336  *   android.request.id (controls and dynamic)
    337  *
    338  *   android.scaler.cropRegion (controls and dynamic)
    339  *   android.scaler.availableStreamConfigurations (static)
    340  *   android.scaler.availableMinFrameDurations (static)
    341  *   android.scaler.availableStallDurations (static)
    342  *   android.scaler.availableMaxDigitalZoom (static)
    343  *   android.scaler.maxDigitalZoom (static)
    344  *   android.scaler.croppingType (static)
    345  *
    346  *   android.sensor.orientation (static)
    347  *   android.sensor.timestamp (dynamic)
    348  *
    349  *   android.statistics.faceDetectMode (controls and dynamic)
    350  *   android.statistics.info.availableFaceDetectModes (static)
    351  *   android.statistics.faceIds (dynamic)
    352  *   android.statistics.faceLandmarks (dynamic)
    353  *   android.statistics.faceRectangles (dynamic)
    354  *   android.statistics.faceScores (dynamic)
    355  *
    356  *   android.sync.frameNumber (dynamic)
    357  *   android.sync.maxLatency (static)
    358  *
    359  * - Captures in limited mode that include high-resolution (> 1080p) output
    360  *   buffers may block in process_capture_request() until all the output buffers
    361  *   have been filled. A full-mode HAL device must process sequences of
    362  *   high-resolution requests at the rate indicated in the static metadata for
    363  *   that pixel format. The HAL must still call process_capture_result() to
    364  *   provide the output; the framework must simply be prepared for
    365  *   process_capture_request() to block until after process_capture_result() for
    366  *   that request completes for high-resolution captures for limited-mode
    367  *   devices.
    368  *
    369  * - Full-mode devices must support below additional capabilities:
    370  *   - 30fps at maximum resolution is preferred, more than 20fps is required.
    371  *   - Per frame control (android.sync.maxLatency == PER_FRAME_CONTROL).
    372  *   - Sensor manual control metadata. See MANUAL_SENSOR defined in
    373  *     android.request.availableCapabilities.
    374  *   - Post-processing manual control metadata. See MANUAL_POST_PROCESSING defined
    375  *     in android.request.availableCapabilities.
    376  *
    377  */
    378 
    379 /**
    380  * S4. 3A modes and state machines:
    381  *
    382  * While the actual 3A algorithms are up to the HAL implementation, a high-level
    383  * state machine description is defined by the HAL interface, to allow the HAL
    384  * device and the framework to communicate about the current state of 3A, and to
    385  * trigger 3A events.
    386  *
    387  * When the device is opened, all the individual 3A states must be
    388  * STATE_INACTIVE. Stream configuration does not reset 3A. For example, locked
    389  * focus must be maintained across the configure() call.
    390  *
    391  * Triggering a 3A action involves simply setting the relevant trigger entry in
    392  * the settings for the next request to indicate start of trigger. For example,
    393  * the trigger for starting an autofocus scan is setting the entry
    394  * ANDROID_CONTROL_AF_TRIGGER to ANDROID_CONTROL_AF_TRIGGER_START for one
    395  * request, and cancelling an autofocus scan is triggered by setting
    396  * ANDROID_CONTROL_AF_TRIGGER to ANDROID_CONTRL_AF_TRIGGER_CANCEL. Otherwise,
    397  * the entry will not exist, or be set to ANDROID_CONTROL_AF_TRIGGER_IDLE. Each
    398  * request with a trigger entry set to a non-IDLE value will be treated as an
    399  * independent triggering event.
    400  *
    401  * At the top level, 3A is controlled by the ANDROID_CONTROL_MODE setting, which
    402  * selects between no 3A (ANDROID_CONTROL_MODE_OFF), normal AUTO mode
    403  * (ANDROID_CONTROL_MODE_AUTO), and using the scene mode setting
    404  * (ANDROID_CONTROL_USE_SCENE_MODE).
    405  *
    406  * - In OFF mode, each of the individual AE/AF/AWB modes are effectively OFF,
    407  *   and none of the capture controls may be overridden by the 3A routines.
    408  *
    409  * - In AUTO mode, Auto-focus, auto-exposure, and auto-whitebalance all run
    410  *   their own independent algorithms, and have their own mode, state, and
    411  *   trigger metadata entries, as listed in the next section.
    412  *
    413  * - In USE_SCENE_MODE, the value of the ANDROID_CONTROL_SCENE_MODE entry must
    414  *   be used to determine the behavior of 3A routines. In SCENE_MODEs other than
    415  *   FACE_PRIORITY, the HAL must override the values of
    416  *   ANDROId_CONTROL_AE/AWB/AF_MODE to be the mode it prefers for the selected
    417  *   SCENE_MODE. For example, the HAL may prefer SCENE_MODE_NIGHT to use
    418  *   CONTINUOUS_FOCUS AF mode. Any user selection of AE/AWB/AF_MODE when scene
    419  *   must be ignored for these scene modes.
    420  *
    421  * - For SCENE_MODE_FACE_PRIORITY, the AE/AWB/AF_MODE controls work as in
    422  *   ANDROID_CONTROL_MODE_AUTO, but the 3A routines must bias toward metering
    423  *   and focusing on any detected faces in the scene.
    424  *
    425  * S4.1. Auto-focus settings and result entries:
    426  *
    427  *  Main metadata entries:
    428  *
    429  *   ANDROID_CONTROL_AF_MODE: Control for selecting the current autofocus
    430  *      mode. Set by the framework in the request settings.
    431  *
    432  *     AF_MODE_OFF: AF is disabled; the framework/app directly controls lens
    433  *         position.
    434  *
    435  *     AF_MODE_AUTO: Single-sweep autofocus. No lens movement unless AF is
    436  *         triggered.
    437  *
    438  *     AF_MODE_MACRO: Single-sweep up-close autofocus. No lens movement unless
    439  *         AF is triggered.
    440  *
    441  *     AF_MODE_CONTINUOUS_VIDEO: Smooth continuous focusing, for recording
    442  *         video. Triggering immediately locks focus in current
    443  *         position. Canceling resumes cotinuous focusing.
    444  *
    445  *     AF_MODE_CONTINUOUS_PICTURE: Fast continuous focusing, for
    446  *        zero-shutter-lag still capture. Triggering locks focus once currently
    447  *        active sweep concludes. Canceling resumes continuous focusing.
    448  *
    449  *     AF_MODE_EDOF: Advanced extended depth of field focusing. There is no
    450  *        autofocus scan, so triggering one or canceling one has no effect.
    451  *        Images are focused automatically by the HAL.
    452  *
    453  *   ANDROID_CONTROL_AF_STATE: Dynamic metadata describing the current AF
    454  *       algorithm state, reported by the HAL in the result metadata.
    455  *
    456  *     AF_STATE_INACTIVE: No focusing has been done, or algorithm was
    457  *        reset. Lens is not moving. Always the state for MODE_OFF or MODE_EDOF.
    458  *        When the device is opened, it must start in this state.
    459  *
    460  *     AF_STATE_PASSIVE_SCAN: A continuous focus algorithm is currently scanning
    461  *        for good focus. The lens is moving.
    462  *
    463  *     AF_STATE_PASSIVE_FOCUSED: A continuous focus algorithm believes it is
    464  *        well focused. The lens is not moving. The HAL may spontaneously leave
    465  *        this state.
    466  *
    467  *     AF_STATE_PASSIVE_UNFOCUSED: A continuous focus algorithm believes it is
    468  *        not well focused. The lens is not moving. The HAL may spontaneously
    469  *        leave this state.
    470  *
    471  *     AF_STATE_ACTIVE_SCAN: A scan triggered by the user is underway.
    472  *
    473  *     AF_STATE_FOCUSED_LOCKED: The AF algorithm believes it is focused. The
    474  *        lens is not moving.
    475  *
    476  *     AF_STATE_NOT_FOCUSED_LOCKED: The AF algorithm has been unable to
    477  *        focus. The lens is not moving.
    478  *
    479  *   ANDROID_CONTROL_AF_TRIGGER: Control for starting an autofocus scan, the
    480  *       meaning of which is mode- and state- dependent. Set by the framework in
    481  *       the request settings.
    482  *
    483  *     AF_TRIGGER_IDLE: No current trigger.
    484  *
    485  *     AF_TRIGGER_START: Trigger start of AF scan. Effect is mode and state
    486  *         dependent.
    487  *
    488  *     AF_TRIGGER_CANCEL: Cancel current AF scan if any, and reset algorithm to
    489  *         default.
    490  *
    491  *  Additional metadata entries:
    492  *
    493  *   ANDROID_CONTROL_AF_REGIONS: Control for selecting the regions of the FOV
    494  *       that should be used to determine good focus. This applies to all AF
    495  *       modes that scan for focus. Set by the framework in the request
    496  *       settings.
    497  *
    498  * S4.2. Auto-exposure settings and result entries:
    499  *
    500  *  Main metadata entries:
    501  *
    502  *   ANDROID_CONTROL_AE_MODE: Control for selecting the current auto-exposure
    503  *       mode. Set by the framework in the request settings.
    504  *
    505  *     AE_MODE_OFF: Autoexposure is disabled; the user controls exposure, gain,
    506  *         frame duration, and flash.
    507  *
    508  *     AE_MODE_ON: Standard autoexposure, with flash control disabled. User may
    509  *         set flash to fire or to torch mode.
    510  *
    511  *     AE_MODE_ON_AUTO_FLASH: Standard autoexposure, with flash on at HAL's
    512  *         discretion for precapture and still capture. User control of flash
    513  *         disabled.
    514  *
    515  *     AE_MODE_ON_ALWAYS_FLASH: Standard autoexposure, with flash always fired
    516  *         for capture, and at HAL's discretion for precapture.. User control of
    517  *         flash disabled.
    518  *
    519  *     AE_MODE_ON_AUTO_FLASH_REDEYE: Standard autoexposure, with flash on at
    520  *         HAL's discretion for precapture and still capture. Use a flash burst
    521  *         at end of precapture sequence to reduce redeye in the final
    522  *         picture. User control of flash disabled.
    523  *
    524  *   ANDROID_CONTROL_AE_STATE: Dynamic metadata describing the current AE
    525  *       algorithm state, reported by the HAL in the result metadata.
    526  *
    527  *     AE_STATE_INACTIVE: Initial AE state after mode switch. When the device is
    528  *         opened, it must start in this state.
    529  *
    530  *     AE_STATE_SEARCHING: AE is not converged to a good value, and is adjusting
    531  *         exposure parameters.
    532  *
    533  *     AE_STATE_CONVERGED: AE has found good exposure values for the current
    534  *         scene, and the exposure parameters are not changing. HAL may
    535  *         spontaneously leave this state to search for better solution.
    536  *
    537  *     AE_STATE_LOCKED: AE has been locked with the AE_LOCK control. Exposure
    538  *         values are not changing.
    539  *
    540  *     AE_STATE_FLASH_REQUIRED: The HAL has converged exposure, but believes
    541  *         flash is required for a sufficiently bright picture. Used for
    542  *         determining if a zero-shutter-lag frame can be used.
    543  *
    544  *     AE_STATE_PRECAPTURE: The HAL is in the middle of a precapture
    545  *         sequence. Depending on AE mode, this mode may involve firing the
    546  *         flash for metering, or a burst of flash pulses for redeye reduction.
    547  *
    548  *   ANDROID_CONTROL_AE_PRECAPTURE_TRIGGER: Control for starting a metering
    549  *       sequence before capturing a high-quality image. Set by the framework in
    550  *       the request settings.
    551  *
    552  *      PRECAPTURE_TRIGGER_IDLE: No current trigger.
    553  *
    554  *      PRECAPTURE_TRIGGER_START: Start a precapture sequence. The HAL should
    555  *         use the subsequent requests to measure good exposure/white balance
    556  *         for an upcoming high-resolution capture.
    557  *
    558  *  Additional metadata entries:
    559  *
    560  *   ANDROID_CONTROL_AE_LOCK: Control for locking AE controls to their current
    561  *       values
    562  *
    563  *   ANDROID_CONTROL_AE_EXPOSURE_COMPENSATION: Control for adjusting AE
    564  *       algorithm target brightness point.
    565  *
    566  *   ANDROID_CONTROL_AE_TARGET_FPS_RANGE: Control for selecting the target frame
    567  *       rate range for the AE algorithm. The AE routine cannot change the frame
    568  *       rate to be outside these bounds.
    569  *
    570  *   ANDROID_CONTROL_AE_REGIONS: Control for selecting the regions of the FOV
    571  *       that should be used to determine good exposure levels. This applies to
    572  *       all AE modes besides OFF.
    573  *
    574  * S4.3. Auto-whitebalance settings and result entries:
    575  *
    576  *  Main metadata entries:
    577  *
    578  *   ANDROID_CONTROL_AWB_MODE: Control for selecting the current white-balance
    579  *       mode.
    580  *
    581  *     AWB_MODE_OFF: Auto-whitebalance is disabled. User controls color matrix.
    582  *
    583  *     AWB_MODE_AUTO: Automatic white balance is enabled; 3A controls color
    584  *        transform, possibly using more complex transforms than a simple
    585  *        matrix.
    586  *
    587  *     AWB_MODE_INCANDESCENT: Fixed white balance settings good for indoor
    588  *        incandescent (tungsten) lighting, roughly 2700K.
    589  *
    590  *     AWB_MODE_FLUORESCENT: Fixed white balance settings good for fluorescent
    591  *        lighting, roughly 5000K.
    592  *
    593  *     AWB_MODE_WARM_FLUORESCENT: Fixed white balance settings good for
    594  *        fluorescent lighting, roughly 3000K.
    595  *
    596  *     AWB_MODE_DAYLIGHT: Fixed white balance settings good for daylight,
    597  *        roughly 5500K.
    598  *
    599  *     AWB_MODE_CLOUDY_DAYLIGHT: Fixed white balance settings good for clouded
    600  *        daylight, roughly 6500K.
    601  *
    602  *     AWB_MODE_TWILIGHT: Fixed white balance settings good for
    603  *        near-sunset/sunrise, roughly 15000K.
    604  *
    605  *     AWB_MODE_SHADE: Fixed white balance settings good for areas indirectly
    606  *        lit by the sun, roughly 7500K.
    607  *
    608  *   ANDROID_CONTROL_AWB_STATE: Dynamic metadata describing the current AWB
    609  *       algorithm state, reported by the HAL in the result metadata.
    610  *
    611  *     AWB_STATE_INACTIVE: Initial AWB state after mode switch. When the device
    612  *         is opened, it must start in this state.
    613  *
    614  *     AWB_STATE_SEARCHING: AWB is not converged to a good value, and is
    615  *         changing color adjustment parameters.
    616  *
    617  *     AWB_STATE_CONVERGED: AWB has found good color adjustment values for the
    618  *         current scene, and the parameters are not changing. HAL may
    619  *         spontaneously leave this state to search for better solution.
    620  *
    621  *     AWB_STATE_LOCKED: AWB has been locked with the AWB_LOCK control. Color
    622  *         adjustment values are not changing.
    623  *
    624  *  Additional metadata entries:
    625  *
    626  *   ANDROID_CONTROL_AWB_LOCK: Control for locking AWB color adjustments to
    627  *       their current values.
    628  *
    629  *   ANDROID_CONTROL_AWB_REGIONS: Control for selecting the regions of the FOV
    630  *       that should be used to determine good color balance. This applies only
    631  *       to auto-WB mode.
    632  *
    633  * S4.4. General state machine transition notes
    634  *
    635  *   Switching between AF, AE, or AWB modes always resets the algorithm's state
    636  *   to INACTIVE.  Similarly, switching between CONTROL_MODE or
    637  *   CONTROL_SCENE_MODE if CONTROL_MODE == USE_SCENE_MODE resets all the
    638  *   algorithm states to INACTIVE.
    639  *
    640  *   The tables below are per-mode.
    641  *
    642  * S4.5. AF state machines
    643  *
    644  *                       when enabling AF or changing AF mode
    645  *| state              | trans. cause  | new state          | notes            |
    646  *+--------------------+---------------+--------------------+------------------+
    647  *| Any                | AF mode change| INACTIVE           |                  |
    648  *+--------------------+---------------+--------------------+------------------+
    649  *
    650  *                            mode = AF_MODE_OFF or AF_MODE_EDOF
    651  *| state              | trans. cause  | new state          | notes            |
    652  *+--------------------+---------------+--------------------+------------------+
    653  *| INACTIVE           |               | INACTIVE           | Never changes    |
    654  *+--------------------+---------------+--------------------+------------------+
    655  *
    656  *                            mode = AF_MODE_AUTO or AF_MODE_MACRO
    657  *| state              | trans. cause  | new state          | notes            |
    658  *+--------------------+---------------+--------------------+------------------+
    659  *| INACTIVE           | AF_TRIGGER    | ACTIVE_SCAN        | Start AF sweep   |
    660  *|                    |               |                    | Lens now moving  |
    661  *+--------------------+---------------+--------------------+------------------+
    662  *| ACTIVE_SCAN        | AF sweep done | FOCUSED_LOCKED     | If AF successful |
    663  *|                    |               |                    | Lens now locked  |
    664  *+--------------------+---------------+--------------------+------------------+
    665  *| ACTIVE_SCAN        | AF sweep done | NOT_FOCUSED_LOCKED | If AF successful |
    666  *|                    |               |                    | Lens now locked  |
    667  *+--------------------+---------------+--------------------+------------------+
    668  *| ACTIVE_SCAN        | AF_CANCEL     | INACTIVE           | Cancel/reset AF  |
    669  *|                    |               |                    | Lens now locked  |
    670  *+--------------------+---------------+--------------------+------------------+
    671  *| FOCUSED_LOCKED     | AF_CANCEL     | INACTIVE           | Cancel/reset AF  |
    672  *+--------------------+---------------+--------------------+------------------+
    673  *| FOCUSED_LOCKED     | AF_TRIGGER    | ACTIVE_SCAN        | Start new sweep  |
    674  *|                    |               |                    | Lens now moving  |
    675  *+--------------------+---------------+--------------------+------------------+
    676  *| NOT_FOCUSED_LOCKED | AF_CANCEL     | INACTIVE           | Cancel/reset AF  |
    677  *+--------------------+---------------+--------------------+------------------+
    678  *| NOT_FOCUSED_LOCKED | AF_TRIGGER    | ACTIVE_SCAN        | Start new sweep  |
    679  *|                    |               |                    | Lens now moving  |
    680  *+--------------------+---------------+--------------------+------------------+
    681  *| All states         | mode change   | INACTIVE           |                  |
    682  *+--------------------+---------------+--------------------+------------------+
    683  *
    684  *                            mode = AF_MODE_CONTINUOUS_VIDEO
    685  *| state              | trans. cause  | new state          | notes            |
    686  *+--------------------+---------------+--------------------+------------------+
    687  *| INACTIVE           | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
    688  *|                    | new scan      |                    | Lens now moving  |
    689  *+--------------------+---------------+--------------------+------------------+
    690  *| INACTIVE           | AF_TRIGGER    | NOT_FOCUSED_LOCKED | AF state query   |
    691  *|                    |               |                    | Lens now locked  |
    692  *+--------------------+---------------+--------------------+------------------+
    693  *| PASSIVE_SCAN       | HAL completes | PASSIVE_FOCUSED    | End AF scan      |
    694  *|                    | current scan  |                    | Lens now locked  |
    695  *+--------------------+---------------+--------------------+------------------+
    696  *| PASSIVE_SCAN       | HAL fails     | PASSIVE_UNFOCUSED  | End AF scan      |
    697  *|                    | current scan  |                    | Lens now locked  |
    698  *+--------------------+---------------+--------------------+------------------+
    699  *| PASSIVE_SCAN       | AF_TRIGGER    | FOCUSED_LOCKED     | Immediate trans. |
    700  *|                    |               |                    | if focus is good |
    701  *|                    |               |                    | Lens now locked  |
    702  *+--------------------+---------------+--------------------+------------------+
    703  *| PASSIVE_SCAN       | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Immediate trans. |
    704  *|                    |               |                    | if focus is bad  |
    705  *|                    |               |                    | Lens now locked  |
    706  *+--------------------+---------------+--------------------+------------------+
    707  *| PASSIVE_SCAN       | AF_CANCEL     | INACTIVE           | Reset lens       |
    708  *|                    |               |                    | position         |
    709  *|                    |               |                    | Lens now locked  |
    710  *+--------------------+---------------+--------------------+------------------+
    711  *| PASSIVE_FOCUSED    | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
    712  *|                    | new scan      |                    | Lens now moving  |
    713  *+--------------------+---------------+--------------------+------------------+
    714  *| PASSIVE_UNFOCUSED  | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
    715  *|                    | new scan      |                    | Lens now moving  |
    716  *+--------------------+---------------+--------------------+------------------+
    717  *| PASSIVE_FOCUSED    | AF_TRIGGER    | FOCUSED_LOCKED     | Immediate trans. |
    718  *|                    |               |                    | Lens now locked  |
    719  *+--------------------+---------------+--------------------+------------------+
    720  *| PASSIVE_UNFOCUSED  | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Immediate trans. |
    721  *|                    |               |                    | Lens now locked  |
    722  *+--------------------+---------------+--------------------+------------------+
    723  *| FOCUSED_LOCKED     | AF_TRIGGER    | FOCUSED_LOCKED     | No effect        |
    724  *+--------------------+---------------+--------------------+------------------+
    725  *| FOCUSED_LOCKED     | AF_CANCEL     | INACTIVE           | Restart AF scan  |
    726  *+--------------------+---------------+--------------------+------------------+
    727  *| NOT_FOCUSED_LOCKED | AF_TRIGGER    | NOT_FOCUSED_LOCKED | No effect        |
    728  *+--------------------+---------------+--------------------+------------------+
    729  *| NOT_FOCUSED_LOCKED | AF_CANCEL     | INACTIVE           | Restart AF scan  |
    730  *+--------------------+---------------+--------------------+------------------+
    731  *
    732  *                            mode = AF_MODE_CONTINUOUS_PICTURE
    733  *| state              | trans. cause  | new state          | notes            |
    734  *+--------------------+---------------+--------------------+------------------+
    735  *| INACTIVE           | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
    736  *|                    | new scan      |                    | Lens now moving  |
    737  *+--------------------+---------------+--------------------+------------------+
    738  *| INACTIVE           | AF_TRIGGER    | NOT_FOCUSED_LOCKED | AF state query   |
    739  *|                    |               |                    | Lens now locked  |
    740  *+--------------------+---------------+--------------------+------------------+
    741  *| PASSIVE_SCAN       | HAL completes | PASSIVE_FOCUSED    | End AF scan      |
    742  *|                    | current scan  |                    | Lens now locked  |
    743  *+--------------------+---------------+--------------------+------------------+
    744  *| PASSIVE_SCAN       | HAL fails     | PASSIVE_UNFOCUSED  | End AF scan      |
    745  *|                    | current scan  |                    | Lens now locked  |
    746  *+--------------------+---------------+--------------------+------------------+
    747  *| PASSIVE_SCAN       | AF_TRIGGER    | FOCUSED_LOCKED     | Eventual trans.  |
    748  *|                    |               |                    | once focus good  |
    749  *|                    |               |                    | Lens now locked  |
    750  *+--------------------+---------------+--------------------+------------------+
    751  *| PASSIVE_SCAN       | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Eventual trans.  |
    752  *|                    |               |                    | if cannot focus  |
    753  *|                    |               |                    | Lens now locked  |
    754  *+--------------------+---------------+--------------------+------------------+
    755  *| PASSIVE_SCAN       | AF_CANCEL     | INACTIVE           | Reset lens       |
    756  *|                    |               |                    | position         |
    757  *|                    |               |                    | Lens now locked  |
    758  *+--------------------+---------------+--------------------+------------------+
    759  *| PASSIVE_FOCUSED    | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
    760  *|                    | new scan      |                    | Lens now moving  |
    761  *+--------------------+---------------+--------------------+------------------+
    762  *| PASSIVE_UNFOCUSED  | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
    763  *|                    | new scan      |                    | Lens now moving  |
    764  *+--------------------+---------------+--------------------+------------------+
    765  *| PASSIVE_FOCUSED    | AF_TRIGGER    | FOCUSED_LOCKED     | Immediate trans. |
    766  *|                    |               |                    | Lens now locked  |
    767  *+--------------------+---------------+--------------------+------------------+
    768  *| PASSIVE_UNFOCUSED  | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Immediate trans. |
    769  *|                    |               |                    | Lens now locked  |
    770  *+--------------------+---------------+--------------------+------------------+
    771  *| FOCUSED_LOCKED     | AF_TRIGGER    | FOCUSED_LOCKED     | No effect        |
    772  *+--------------------+---------------+--------------------+------------------+
    773  *| FOCUSED_LOCKED     | AF_CANCEL     | INACTIVE           | Restart AF scan  |
    774  *+--------------------+---------------+--------------------+------------------+
    775  *| NOT_FOCUSED_LOCKED | AF_TRIGGER    | NOT_FOCUSED_LOCKED | No effect        |
    776  *+--------------------+---------------+--------------------+------------------+
    777  *| NOT_FOCUSED_LOCKED | AF_CANCEL     | INACTIVE           | Restart AF scan  |
    778  *+--------------------+---------------+--------------------+------------------+
    779  *
    780  * S4.6. AE and AWB state machines
    781  *
    782  *   The AE and AWB state machines are mostly identical. AE has additional
    783  *   FLASH_REQUIRED and PRECAPTURE states. So rows below that refer to those two
    784  *   states should be ignored for the AWB state machine.
    785  *
    786  *                  when enabling AE/AWB or changing AE/AWB mode
    787  *| state              | trans. cause  | new state          | notes            |
    788  *+--------------------+---------------+--------------------+------------------+
    789  *| Any                |  mode change  | INACTIVE           |                  |
    790  *+--------------------+---------------+--------------------+------------------+
    791  *
    792  *                            mode = AE_MODE_OFF / AWB mode not AUTO
    793  *| state              | trans. cause  | new state          | notes            |
    794  *+--------------------+---------------+--------------------+------------------+
    795  *| INACTIVE           |               | INACTIVE           | AE/AWB disabled  |
    796  *+--------------------+---------------+--------------------+------------------+
    797  *
    798  *                            mode = AE_MODE_ON_* / AWB_MODE_AUTO
    799  *| state              | trans. cause  | new state          | notes            |
    800  *+--------------------+---------------+--------------------+------------------+
    801  *| INACTIVE           | HAL initiates | SEARCHING          |                  |
    802  *|                    | AE/AWB scan   |                    |                  |
    803  *+--------------------+---------------+--------------------+------------------+
    804  *| INACTIVE           | AE/AWB_LOCK   | LOCKED             | values locked    |
    805  *|                    | on            |                    |                  |
    806  *+--------------------+---------------+--------------------+------------------+
    807  *| SEARCHING          | HAL finishes  | CONVERGED          | good values, not |
    808  *|                    | AE/AWB scan   |                    | changing         |
    809  *+--------------------+---------------+--------------------+------------------+
    810  *| SEARCHING          | HAL finishes  | FLASH_REQUIRED     | converged but too|
    811  *|                    | AE scan       |                    | dark w/o flash   |
    812  *+--------------------+---------------+--------------------+------------------+
    813  *| SEARCHING          | AE/AWB_LOCK   | LOCKED             | values locked    |
    814  *|                    | on            |                    |                  |
    815  *+--------------------+---------------+--------------------+------------------+
    816  *| CONVERGED          | HAL initiates | SEARCHING          | values locked    |
    817  *|                    | AE/AWB scan   |                    |                  |
    818  *+--------------------+---------------+--------------------+------------------+
    819  *| CONVERGED          | AE/AWB_LOCK   | LOCKED             | values locked    |
    820  *|                    | on            |                    |                  |
    821  *+--------------------+---------------+--------------------+------------------+
    822  *| FLASH_REQUIRED     | HAL initiates | SEARCHING          | values locked    |
    823  *|                    | AE/AWB scan   |                    |                  |
    824  *+--------------------+---------------+--------------------+------------------+
    825  *| FLASH_REQUIRED     | AE/AWB_LOCK   | LOCKED             | values locked    |
    826  *|                    | on            |                    |                  |
    827  *+--------------------+---------------+--------------------+------------------+
    828  *| LOCKED             | AE/AWB_LOCK   | SEARCHING          | values not good  |
    829  *|                    | off           |                    | after unlock     |
    830  *+--------------------+---------------+--------------------+------------------+
    831  *| LOCKED             | AE/AWB_LOCK   | CONVERGED          | values good      |
    832  *|                    | off           |                    | after unlock     |
    833  *+--------------------+---------------+--------------------+------------------+
    834  *| LOCKED             | AE_LOCK       | FLASH_REQUIRED     | exposure good,   |
    835  *|                    | off           |                    | but too dark     |
    836  *+--------------------+---------------+--------------------+------------------+
    837  *| All AE states      | PRECAPTURE_   | PRECAPTURE         | Start precapture |
    838  *|                    | START         |                    | sequence         |
    839  *+--------------------+---------------+--------------------+------------------+
    840  *| PRECAPTURE         | Sequence done.| CONVERGED          | Ready for high-  |
    841  *|                    | AE_LOCK off   |                    | quality capture  |
    842  *+--------------------+---------------+--------------------+------------------+
    843  *| PRECAPTURE         | Sequence done.| LOCKED             | Ready for high-  |
    844  *|                    | AE_LOCK on    |                    | quality capture  |
    845  *+--------------------+---------------+--------------------+------------------+
    846  *
    847  */
    848 
    849 /**
    850  * S5. Cropping:
    851  *
    852  * Cropping of the full pixel array (for digital zoom and other use cases where
    853  * a smaller FOV is desirable) is communicated through the
    854  * ANDROID_SCALER_CROP_REGION setting. This is a per-request setting, and can
    855  * change on a per-request basis, which is critical for implementing smooth
    856  * digital zoom.
    857  *
    858  * The region is defined as a rectangle (x, y, width, height), with (x, y)
    859  * describing the top-left corner of the rectangle. The rectangle is defined on
    860  * the coordinate system of the sensor active pixel array, with (0,0) being the
    861  * top-left pixel of the active pixel array. Therefore, the width and height
    862  * cannot be larger than the dimensions reported in the
    863  * ANDROID_SENSOR_ACTIVE_PIXEL_ARRAY static info field. The minimum allowed
    864  * width and height are reported by the HAL through the
    865  * ANDROID_SCALER_MAX_DIGITAL_ZOOM static info field, which describes the
    866  * maximum supported zoom factor. Therefore, the minimum crop region width and
    867  * height are:
    868  *
    869  * {width, height} =
    870  *    { floor(ANDROID_SENSOR_ACTIVE_PIXEL_ARRAY[0] /
    871  *        ANDROID_SCALER_MAX_DIGITAL_ZOOM),
    872  *      floor(ANDROID_SENSOR_ACTIVE_PIXEL_ARRAY[1] /
    873  *        ANDROID_SCALER_MAX_DIGITAL_ZOOM) }
    874  *
    875  * If the crop region needs to fulfill specific requirements (for example, it
    876  * needs to start on even coordinates, and its width/height needs to be even),
    877  * the HAL must do the necessary rounding and write out the final crop region
    878  * used in the output result metadata. Similarly, if the HAL implements video
    879  * stabilization, it must adjust the result crop region to describe the region
    880  * actually included in the output after video stabilization is applied. In
    881  * general, a camera-using application must be able to determine the field of
    882  * view it is receiving based on the crop region, the dimensions of the image
    883  * sensor, and the lens focal length.
    884  *
    885  * It is assumed that the cropping is applied after raw to other color space
    886  * conversion. Raw streams (RAW16 and RAW_OPAQUE) don't have this conversion stage,
    887  * and are not croppable. Therefore, the crop region must be ignored by the HAL
    888  * for raw streams.
    889  *
    890  * Since the crop region applies to all non-raw streams, which may have different aspect
    891  * ratios than the crop region, the exact sensor region used for each stream may
    892  * be smaller than the crop region. Specifically, each stream should maintain
    893  * square pixels and its aspect ratio by minimally further cropping the defined
    894  * crop region. If the stream's aspect ratio is wider than the crop region, the
    895  * stream should be further cropped vertically, and if the stream's aspect ratio
    896  * is narrower than the crop region, the stream should be further cropped
    897  * horizontally.
    898  *
    899  * In all cases, the stream crop must be centered within the full crop region,
    900  * and each stream is only either cropped horizontally or vertical relative to
    901  * the full crop region, never both.
    902  *
    903  * For example, if two streams are defined, a 640x480 stream (4:3 aspect), and a
    904  * 1280x720 stream (16:9 aspect), below demonstrates the expected output regions
    905  * for each stream for a few sample crop regions, on a hypothetical 3 MP (2000 x
    906  * 1500 pixel array) sensor.
    907  *
    908  * Crop region: (500, 375, 1000, 750) (4:3 aspect ratio)
    909  *
    910  *   640x480 stream crop: (500, 375, 1000, 750) (equal to crop region)
    911  *   1280x720 stream crop: (500, 469, 1000, 562) (marked with =)
    912  *
    913  * 0                   1000               2000
    914  * +---------+---------+---------+----------+
    915  * | Active pixel array                     |
    916  * |                                        |
    917  * |                                        |
    918  * +         +-------------------+          + 375
    919  * |         |                   |          |
    920  * |         O===================O          |
    921  * |         I 1280x720 stream   I          |
    922  * +         I                   I          + 750
    923  * |         I                   I          |
    924  * |         O===================O          |
    925  * |         |                   |          |
    926  * +         +-------------------+          + 1125
    927  * |          Crop region, 640x480 stream   |
    928  * |                                        |
    929  * |                                        |
    930  * +---------+---------+---------+----------+ 1500
    931  *
    932  * Crop region: (500, 375, 1333, 750) (16:9 aspect ratio)
    933  *
    934  *   640x480 stream crop: (666, 375, 1000, 750) (marked with =)
    935  *   1280x720 stream crop: (500, 375, 1333, 750) (equal to crop region)
    936  *
    937  * 0                   1000               2000
    938  * +---------+---------+---------+----------+
    939  * | Active pixel array                     |
    940  * |                                        |
    941  * |                                        |
    942  * +         +---O==================O---+   + 375
    943  * |         |   I 640x480 stream   I   |   |
    944  * |         |   I                  I   |   |
    945  * |         |   I                  I   |   |
    946  * +         |   I                  I   |   + 750
    947  * |         |   I                  I   |   |
    948  * |         |   I                  I   |   |
    949  * |         |   I                  I   |   |
    950  * +         +---O==================O---+   + 1125
    951  * |          Crop region, 1280x720 stream  |
    952  * |                                        |
    953  * |                                        |
    954  * +---------+---------+---------+----------+ 1500
    955  *
    956  * Crop region: (500, 375, 750, 750) (1:1 aspect ratio)
    957  *
    958  *   640x480 stream crop: (500, 469, 750, 562) (marked with =)
    959  *   1280x720 stream crop: (500, 543, 750, 414) (marged with #)
    960  *
    961  * 0                   1000               2000
    962  * +---------+---------+---------+----------+
    963  * | Active pixel array                     |
    964  * |                                        |
    965  * |                                        |
    966  * +         +--------------+               + 375
    967  * |         O==============O               |
    968  * |         ################               |
    969  * |         #              #               |
    970  * +         #              #               + 750
    971  * |         #              #               |
    972  * |         ################ 1280x720      |
    973  * |         O==============O 640x480       |
    974  * +         +--------------+               + 1125
    975  * |          Crop region                   |
    976  * |                                        |
    977  * |                                        |
    978  * +---------+---------+---------+----------+ 1500
    979  *
    980  * And a final example, a 1024x1024 square aspect ratio stream instead of the
    981  * 480p stream:
    982  *
    983  * Crop region: (500, 375, 1000, 750) (4:3 aspect ratio)
    984  *
    985  *   1024x1024 stream crop: (625, 375, 750, 750) (marked with #)
    986  *   1280x720 stream crop: (500, 469, 1000, 562) (marked with =)
    987  *
    988  * 0                   1000               2000
    989  * +---------+---------+---------+----------+
    990  * | Active pixel array                     |
    991  * |                                        |
    992  * |              1024x1024 stream          |
    993  * +         +--###############--+          + 375
    994  * |         |  #             #  |          |
    995  * |         O===================O          |
    996  * |         I 1280x720 stream   I          |
    997  * +         I                   I          + 750
    998  * |         I                   I          |
    999  * |         O===================O          |
   1000  * |         |  #             #  |          |
   1001  * +         +--###############--+          + 1125
   1002  * |          Crop region                   |
   1003  * |                                        |
   1004  * |                                        |
   1005  * +---------+---------+---------+----------+ 1500
   1006  *
   1007  */
   1008 
   1009 /**
   1010  * S6. Error management:
   1011  *
   1012  * Camera HAL device ops functions that have a return value will all return
   1013  * -ENODEV / NULL in case of a serious error. This means the device cannot
   1014  * continue operation, and must be closed by the framework. Once this error is
   1015  * returned by some method, or if notify() is called with ERROR_DEVICE, only
   1016  * the close() method can be called successfully. All other methods will return
   1017  * -ENODEV / NULL.
   1018  *
   1019  * If a device op is called in the wrong sequence, for example if the framework
   1020  * calls configure_streams() is called before initialize(), the device must
   1021  * return -ENOSYS from the call, and do nothing.
   1022  *
   1023  * Transient errors in image capture must be reported through notify() as follows:
   1024  *
   1025  * - The failure of an entire capture to occur must be reported by the HAL by
   1026  *   calling notify() with ERROR_REQUEST. Individual errors for the result
   1027  *   metadata or the output buffers must not be reported in this case.
   1028  *
   1029  * - If the metadata for a capture cannot be produced, but some image buffers
   1030  *   were filled, the HAL must call notify() with ERROR_RESULT.
   1031  *
   1032  * - If an output image buffer could not be filled, but either the metadata was
   1033  *   produced or some other buffers were filled, the HAL must call notify() with
   1034  *   ERROR_BUFFER for each failed buffer.
   1035  *
   1036  * In each of these transient failure cases, the HAL must still call
   1037  * process_capture_result, with valid output and input (if an input buffer was
   1038  * submitted) buffer_handle_t. If the result metadata could not be produced, it
   1039  * should be NULL. If some buffers could not be filled, they must be returned with
   1040  * process_capture_result in the error state, their release fences must be set to
   1041  * the acquire fences passed by the framework, or -1 if they have been waited on by
   1042  * the HAL already.
   1043  *
   1044  * Invalid input arguments result in -EINVAL from the appropriate methods. In
   1045  * that case, the framework must act as if that call had never been made.
   1046  *
   1047  */
   1048 
   1049 /**
   1050  * S7. Key Performance Indicator (KPI) glossary:
   1051  *
   1052  * This includes some critical definitions that are used by KPI metrics.
   1053  *
   1054  * Pipeline Latency:
   1055  *  For a given capture request, the duration from the framework calling
   1056  *  process_capture_request to the HAL sending capture result and all buffers
   1057  *  back by process_capture_result call. To make the Pipeline Latency measure
   1058  *  independent of frame rate, it is measured by frame count.
   1059  *
   1060  *  For example, when frame rate is 30 (fps), the frame duration (time interval
   1061  *  between adjacent frame capture time) is 33 (ms).
   1062  *  If it takes 5 frames for framework to get the result and buffers back for
   1063  *  a given request, then the Pipeline Latency is 5 (frames), instead of
   1064  *  5 x 33 = 165 (ms).
   1065  *
   1066  *  The Pipeline Latency is determined by android.request.pipelineDepth and
   1067  *  android.request.pipelineMaxDepth, see their definitions for more details.
   1068  *
   1069  */
   1070 
   1071 /**
   1072  * S8. Sample Use Cases:
   1073  *
   1074  * This includes some typical use case examples the camera HAL may support.
   1075  *
   1076  * S8.1 Zero Shutter Lag (ZSL) with CAMERA3_STREAM_INPUT stream.
   1077  *
   1078  *   When Zero Shutter Lag (ZSL) is supported by the camera device, the INPUT stream
   1079  *   can be used for application/framework implemented ZSL use case. This kind of stream
   1080  *   will be used by the framework as follows:
   1081  *
   1082  *   1. Framework configures an opaque raw format output stream that is used to
   1083  *      produce the ZSL output buffers. The stream pixel format will be
   1084  *      HAL_PIXEL_FORMAT_RAW_OPAQUE.
   1085  *
   1086  *   2. Framework configures an opaque raw format input stream that is used to
   1087  *      send the reprocess ZSL buffers to the HAL. The stream pixel format will
   1088  *      also be HAL_PIXEL_FORMAT_RAW_OPAQUE.
   1089  *
   1090  *   3. Framework configures a YUV/JPEG output stream that is used to receive the
   1091  *      reprocessed data. The stream pixel format will be YCbCr_420/HAL_PIXEL_FORMAT_BLOB.
   1092  *
   1093  *   4. Framework picks a ZSL buffer from the output stream when a ZSL capture is
   1094  *      issued by the application, and sends the data back as an input buffer in a
   1095  *      reprocessing request, then sends to the HAL for reprocessing.
   1096  *
   1097  *   5. The HAL sends back the output JPEG result to framework.
   1098  *
   1099  *   The HAL can select the actual raw buffer format and configure the ISP pipeline
   1100  *   appropriately based on the HAL_PIXEL_FORMAT_RAW_OPAQUE format. See this format
   1101  *   definition for more details.
   1102  *
   1103  * S8.2 Zero Shutter Lag (ZSL) with CAMERA3_STREAM_BIDIRECTIONAL stream.
   1104  *
   1105  *   For this use case, the bidirectional stream will be used by the framework as follows:
   1106  *
   1107  *   1. The framework includes a buffer from this stream as output buffer in a
   1108  *      request as normal.
   1109  *
   1110  *   2. Once the HAL device returns a filled output buffer to the framework,
   1111  *      the framework may do one of two things with the filled buffer:
   1112  *
   1113  *   2. a. The framework uses the filled data, and returns the now-used buffer
   1114  *         to the stream queue for reuse. This behavior exactly matches the
   1115  *         OUTPUT type of stream.
   1116  *
   1117  *   2. b. The framework wants to reprocess the filled data, and uses the
   1118  *         buffer as an input buffer for a request. Once the HAL device has
   1119  *         used the reprocessing buffer, it then returns it to the
   1120  *         framework. The framework then returns the now-used buffer to the
   1121  *         stream queue for reuse.
   1122  *
   1123  *   3. The HAL device will be given the buffer again as an output buffer for
   1124  *        a request at some future point.
   1125  *
   1126  *   For ZSL use case, the pixel format for bidirectional stream will be
   1127  *   HAL_PIXEL_FORMAT_RAW_OPAQUE or HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED if it
   1128  *   is listed in android.scaler.availableInputOutputFormatsMap. When
   1129  *   HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED is used, the gralloc
   1130  *   usage flags for the consumer endpoint will be set to GRALLOC_USAGE_HW_CAMERA_ZSL.
   1131  *   A configuration stream list that has BIDIRECTIONAL stream used as input, will
   1132  *   usually also have a distinct OUTPUT stream to get the reprocessing data. For example,
   1133  *   for the ZSL use case, the stream list might be configured with the following:
   1134  *
   1135  *     - A HAL_PIXEL_FORMAT_RAW_OPAQUE bidirectional stream is used
   1136  *       as input.
   1137  *     - And a HAL_PIXEL_FORMAT_BLOB (JPEG) output stream.
   1138  *
   1139  */
   1140 
   1141 /**
   1142  *   S9. Notes on Controls and Metadata
   1143  *
   1144  *   This section contains notes about the interpretation and usage of various metadata tags.
   1145  *
   1146  *   S9.1 HIGH_QUALITY and FAST modes.
   1147  *
   1148  *   Many camera post-processing blocks may be listed as having HIGH_QUALITY,
   1149  *   FAST, and OFF operating modes. These blocks will typically also have an
   1150  *   'available modes' tag representing which of these operating modes are
   1151  *   available on a given device. The general policy regarding implementing
   1152  *   these modes is as follows:
   1153  *
   1154  *   1. Operating mode controls of hardware blocks that cannot be disabled
   1155  *      must not list OFF in their corresponding 'available modes' tags.
   1156  *
   1157  *   2. OFF will always be included in their corresponding 'available modes'
   1158  *      tag if it is possible to disable that hardware block.
   1159  *
   1160  *   3. FAST must always be included in the 'available modes' tags for all
   1161  *      post-processing blocks supported on the device.  If a post-processing
   1162  *      block also has a slower and higher quality operating mode that does
   1163  *      not meet the framerate requirements for FAST mode, HIGH_QUALITY should
   1164  *      be included in the 'available modes' tag to represent this operating
   1165  *      mode.
   1166  */
   1167 __BEGIN_DECLS
   1168 
   1169 struct camera3_device;
   1170 
   1171 /**********************************************************************
   1172  *
   1173  * Camera3 stream and stream buffer definitions.
   1174  *
   1175  * These structs and enums define the handles and contents of the input and
   1176  * output streams connecting the HAL to various framework and application buffer
   1177  * consumers. Each stream is backed by a gralloc buffer queue.
   1178  *
   1179  */
   1180 
   1181 /**
   1182  * camera3_stream_type_t:
   1183  *
   1184  * The type of the camera stream, which defines whether the camera HAL device is
   1185  * the producer or the consumer for that stream, and how the buffers of the
   1186  * stream relate to the other streams.
   1187  */
   1188 typedef enum camera3_stream_type {
   1189     /**
   1190      * This stream is an output stream; the camera HAL device will be
   1191      * responsible for filling buffers from this stream with newly captured or
   1192      * reprocessed image data.
   1193      */
   1194     CAMERA3_STREAM_OUTPUT = 0,
   1195 
   1196     /**
   1197      * This stream is an input stream; the camera HAL device will be responsible
   1198      * for reading buffers from this stream and sending them through the camera
   1199      * processing pipeline, as if the buffer was a newly captured image from the
   1200      * imager.
   1201      *
   1202      * The pixel format for input stream can be any format reported by
   1203      * android.scaler.availableInputOutputFormatsMap. The pixel format of the
   1204      * output stream that is used to produce the reprocessing data may be any
   1205      * format reported by android.scaler.availableStreamConfigurations. The
   1206      * supported input/output stream combinations depends the camera device
   1207      * capabilities, see android.scaler.availableInputOutputFormatsMap for
   1208      * stream map details.
   1209      *
   1210      * This kind of stream is generally used to reprocess data into higher
   1211      * quality images (that otherwise would cause a frame rate performance
   1212      * loss), or to do off-line reprocessing.
   1213      *
   1214      * A typical use case is Zero Shutter Lag (ZSL), see S8.1 for more details.
   1215      *
   1216      */
   1217     CAMERA3_STREAM_INPUT = 1,
   1218 
   1219     /**
   1220      * This stream can be used for input and output. Typically, the stream is
   1221      * used as an output stream, but occasionally one already-filled buffer may
   1222      * be sent back to the HAL device for reprocessing.
   1223      *
   1224      * This kind of stream is meant generally for Zero Shutter Lag (ZSL)
   1225      * features, where copying the captured image from the output buffer to the
   1226      * reprocessing input buffer would be expensive. See S8.2 for more details.
   1227      *
   1228      * Note that the HAL will always be reprocessing data it produced.
   1229      *
   1230      */
   1231     CAMERA3_STREAM_BIDIRECTIONAL = 2,
   1232 
   1233     /**
   1234      * Total number of framework-defined stream types
   1235      */
   1236     CAMERA3_NUM_STREAM_TYPES
   1237 
   1238 } camera3_stream_type_t;
   1239 
   1240 /**
   1241  * camera3_stream_t:
   1242  *
   1243  * A handle to a single camera input or output stream. A stream is defined by
   1244  * the framework by its buffer resolution and format, and additionally by the
   1245  * HAL with the gralloc usage flags and the maximum in-flight buffer count.
   1246  *
   1247  * The stream structures are owned by the framework, but pointers to a
   1248  * camera3_stream passed into the HAL by configure_streams() are valid until the
   1249  * end of the first subsequent configure_streams() call that _does not_ include
   1250  * that camera3_stream as an argument, or until the end of the close() call.
   1251  *
   1252  * All camera3_stream framework-controlled members are immutable once the
   1253  * camera3_stream is passed into configure_streams().  The HAL may only change
   1254  * the HAL-controlled parameters during a configure_streams() call, except for
   1255  * the contents of the private pointer.
   1256  *
   1257  * If a configure_streams() call returns a non-fatal error, all active streams
   1258  * remain valid as if configure_streams() had not been called.
   1259  *
   1260  * The endpoint of the stream is not visible to the camera HAL device.
   1261  * In DEVICE_API_VERSION_3_1, this was changed to share consumer usage flags
   1262  * on streams where the camera is a producer (OUTPUT and BIDIRECTIONAL stream
   1263  * types) see the usage field below.
   1264  */
   1265 typedef struct camera3_stream {
   1266 
   1267     /*****
   1268      * Set by framework before configure_streams()
   1269      */
   1270 
   1271     /**
   1272      * The type of the stream, one of the camera3_stream_type_t values.
   1273      */
   1274     int stream_type;
   1275 
   1276     /**
   1277      * The width in pixels of the buffers in this stream
   1278      */
   1279     uint32_t width;
   1280 
   1281     /**
   1282      * The height in pixels of the buffers in this stream
   1283      */
   1284     uint32_t height;
   1285 
   1286     /**
   1287      * The pixel format for the buffers in this stream. Format is a value from
   1288      * the HAL_PIXEL_FORMAT_* list in system/core/include/system/graphics.h, or
   1289      * from device-specific headers.
   1290      *
   1291      * If HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED is used, then the platform
   1292      * gralloc module will select a format based on the usage flags provided by
   1293      * the camera device and the other endpoint of the stream.
   1294      *
   1295      * <= CAMERA_DEVICE_API_VERSION_3_1:
   1296      *
   1297      * The camera HAL device must inspect the buffers handed to it in the
   1298      * subsequent register_stream_buffers() call to obtain the
   1299      * implementation-specific format details, if necessary.
   1300      *
   1301      * >= CAMERA_DEVICE_API_VERSION_3_2:
   1302      *
   1303      * register_stream_buffers() won't be called by the framework, so the HAL
   1304      * should configure the ISP and sensor pipeline based purely on the sizes,
   1305      * usage flags, and formats for the configured streams.
   1306      */
   1307     int format;
   1308 
   1309     /*****
   1310      * Set by HAL during configure_streams().
   1311      */
   1312 
   1313     /**
   1314      * The gralloc usage flags for this stream, as needed by the HAL. The usage
   1315      * flags are defined in gralloc.h (GRALLOC_USAGE_*), or in device-specific
   1316      * headers.
   1317      *
   1318      * For output streams, these are the HAL's producer usage flags. For input
   1319      * streams, these are the HAL's consumer usage flags. The usage flags from
   1320      * the producer and the consumer will be combined together and then passed
   1321      * to the platform gralloc HAL module for allocating the gralloc buffers for
   1322      * each stream.
   1323      *
   1324      * Version information:
   1325      *
   1326      * == CAMERA_DEVICE_API_VERSION_3_0:
   1327      *
   1328      *   No initial value guaranteed when passed via configure_streams().
   1329      *   HAL may not use this field as input, and must write over this field
   1330      *   with its usage flags.
   1331      *
   1332      * >= CAMERA_DEVICE_API_VERSION_3_1:
   1333      *
   1334      *   For stream_type OUTPUT and BIDIRECTIONAL, when passed via
   1335      *   configure_streams(), the initial value of this is the consumer's
   1336      *   usage flags.  The HAL may use these consumer flags to decide stream
   1337      *   configuration.
   1338      *   For stream_type INPUT, when passed via configure_streams(), the initial
   1339      *   value of this is 0.
   1340      *   For all streams passed via configure_streams(), the HAL must write
   1341      *   over this field with its usage flags.
   1342      */
   1343     uint32_t usage;
   1344 
   1345     /**
   1346      * The maximum number of buffers the HAL device may need to have dequeued at
   1347      * the same time. The HAL device may not have more buffers in-flight from
   1348      * this stream than this value.
   1349      */
   1350     uint32_t max_buffers;
   1351 
   1352     /**
   1353      * A handle to HAL-private information for the stream. Will not be inspected
   1354      * by the framework code.
   1355      */
   1356     void *priv;
   1357 
   1358 } camera3_stream_t;
   1359 
   1360 /**
   1361  * camera3_stream_configuration_t:
   1362  *
   1363  * A structure of stream definitions, used by configure_streams(). This
   1364  * structure defines all the output streams and the reprocessing input
   1365  * stream for the current camera use case.
   1366  */
   1367 typedef struct camera3_stream_configuration {
   1368     /**
   1369      * The total number of streams requested by the framework.  This includes
   1370      * both input and output streams. The number of streams will be at least 1,
   1371      * and there will be at least one output-capable stream.
   1372      */
   1373     uint32_t num_streams;
   1374 
   1375     /**
   1376      * An array of camera stream pointers, defining the input/output
   1377      * configuration for the camera HAL device.
   1378      *
   1379      * At most one input-capable stream may be defined (INPUT or BIDIRECTIONAL)
   1380      * in a single configuration.
   1381      *
   1382      * At least one output-capable stream must be defined (OUTPUT or
   1383      * BIDIRECTIONAL).
   1384      */
   1385     camera3_stream_t **streams;
   1386 
   1387 } camera3_stream_configuration_t;
   1388 
   1389 /**
   1390  * camera3_buffer_status_t:
   1391  *
   1392  * The current status of a single stream buffer.
   1393  */
   1394 typedef enum camera3_buffer_status {
   1395     /**
   1396      * The buffer is in a normal state, and can be used after waiting on its
   1397      * sync fence.
   1398      */
   1399     CAMERA3_BUFFER_STATUS_OK = 0,
   1400 
   1401     /**
   1402      * The buffer does not contain valid data, and the data in it should not be
   1403      * used. The sync fence must still be waited on before reusing the buffer.
   1404      */
   1405     CAMERA3_BUFFER_STATUS_ERROR = 1
   1406 
   1407 } camera3_buffer_status_t;
   1408 
   1409 /**
   1410  * camera3_stream_buffer_t:
   1411  *
   1412  * A single buffer from a camera3 stream. It includes a handle to its parent
   1413  * stream, the handle to the gralloc buffer itself, and sync fences
   1414  *
   1415  * The buffer does not specify whether it is to be used for input or output;
   1416  * that is determined by its parent stream type and how the buffer is passed to
   1417  * the HAL device.
   1418  */
   1419 typedef struct camera3_stream_buffer {
   1420     /**
   1421      * The handle of the stream this buffer is associated with
   1422      */
   1423     camera3_stream_t *stream;
   1424 
   1425     /**
   1426      * The native handle to the buffer
   1427      */
   1428     buffer_handle_t *buffer;
   1429 
   1430     /**
   1431      * Current state of the buffer, one of the camera3_buffer_status_t
   1432      * values. The framework will not pass buffers to the HAL that are in an
   1433      * error state. In case a buffer could not be filled by the HAL, it must
   1434      * have its status set to CAMERA3_BUFFER_STATUS_ERROR when returned to the
   1435      * framework with process_capture_result().
   1436      */
   1437     int status;
   1438 
   1439     /**
   1440      * The acquire sync fence for this buffer. The HAL must wait on this fence
   1441      * fd before attempting to read from or write to this buffer.
   1442      *
   1443      * The framework may be set to -1 to indicate that no waiting is necessary
   1444      * for this buffer.
   1445      *
   1446      * When the HAL returns an output buffer to the framework with
   1447      * process_capture_result(), the acquire_fence must be set to -1. If the HAL
   1448      * never waits on the acquire_fence due to an error in filling a buffer,
   1449      * when calling process_capture_result() the HAL must set the release_fence
   1450      * of the buffer to be the acquire_fence passed to it by the framework. This
   1451      * will allow the framework to wait on the fence before reusing the buffer.
   1452      *
   1453      * For input buffers, the HAL must not change the acquire_fence field during
   1454      * the process_capture_request() call.
   1455      *
   1456      * >= CAMERA_DEVICE_API_VERSION_3_2:
   1457      *
   1458      * When the HAL returns an input buffer to the framework with
   1459      * process_capture_result(), the acquire_fence must be set to -1. If the HAL
   1460      * never waits on input buffer acquire fence due to an error, the sync
   1461      * fences should be handled similarly to the way they are handled for output
   1462      * buffers.
   1463      */
   1464      int acquire_fence;
   1465 
   1466     /**
   1467      * The release sync fence for this buffer. The HAL must set this fence when
   1468      * returning buffers to the framework, or write -1 to indicate that no
   1469      * waiting is required for this buffer.
   1470      *
   1471      * For the output buffers, the fences must be set in the output_buffers
   1472      * array passed to process_capture_result().
   1473      *
   1474      * <= CAMERA_DEVICE_API_VERSION_3_1:
   1475      *
   1476      * For the input buffer, the release fence must be set by the
   1477      * process_capture_request() call.
   1478      *
   1479      * >= CAMERA_DEVICE_API_VERSION_3_2:
   1480      *
   1481      * For the input buffer, the fences must be set in the input_buffer
   1482      * passed to process_capture_result().
   1483      *
   1484      * After signaling the release_fence for this buffer, the HAL
   1485      * should not make any further attempts to access this buffer as the
   1486      * ownership has been fully transferred back to the framework.
   1487      *
   1488      * If a fence of -1 was specified then the ownership of this buffer
   1489      * is transferred back immediately upon the call of process_capture_result.
   1490      */
   1491     int release_fence;
   1492 
   1493 } camera3_stream_buffer_t;
   1494 
   1495 /**
   1496  * camera3_stream_buffer_set_t:
   1497  *
   1498  * The complete set of gralloc buffers for a stream. This structure is given to
   1499  * register_stream_buffers() to allow the camera HAL device to register/map/etc
   1500  * newly allocated stream buffers.
   1501  *
   1502  * >= CAMERA_DEVICE_API_VERSION_3_2:
   1503  *
   1504  * Deprecated (and not used). In particular,
   1505  * register_stream_buffers is also deprecated and will never be invoked.
   1506  *
   1507  */
   1508 typedef struct camera3_stream_buffer_set {
   1509     /**
   1510      * The stream handle for the stream these buffers belong to
   1511      */
   1512     camera3_stream_t *stream;
   1513 
   1514     /**
   1515      * The number of buffers in this stream. It is guaranteed to be at least
   1516      * stream->max_buffers.
   1517      */
   1518     uint32_t num_buffers;
   1519 
   1520     /**
   1521      * The array of gralloc buffer handles for this stream. If the stream format
   1522      * is set to HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, the camera HAL device
   1523      * should inspect the passed-in buffers to determine any platform-private
   1524      * pixel format information.
   1525      */
   1526     buffer_handle_t **buffers;
   1527 
   1528 } camera3_stream_buffer_set_t;
   1529 
   1530 /**
   1531  * camera3_jpeg_blob:
   1532  *
   1533  * Transport header for compressed JPEG buffers in output streams.
   1534  *
   1535  * To capture JPEG images, a stream is created using the pixel format
   1536  * HAL_PIXEL_FORMAT_BLOB. The buffer size for the stream is calculated by the
   1537  * framework, based on the static metadata field android.jpeg.maxSize. Since
   1538  * compressed JPEG images are of variable size, the HAL needs to include the
   1539  * final size of the compressed image using this structure inside the output
   1540  * stream buffer. The JPEG blob ID field must be set to CAMERA3_JPEG_BLOB_ID.
   1541  *
   1542  * Transport header should be at the end of the JPEG output stream buffer. That
   1543  * means the jpeg_blob_id must start at byte[buffer_size -
   1544  * sizeof(camera3_jpeg_blob)], where the buffer_size is the size of gralloc buffer.
   1545  * Any HAL using this transport header must account for it in android.jpeg.maxSize
   1546  * The JPEG data itself starts at the beginning of the buffer and should be
   1547  * jpeg_size bytes long.
   1548  */
   1549 typedef struct camera3_jpeg_blob {
   1550     uint16_t jpeg_blob_id;
   1551     uint32_t jpeg_size;
   1552 } camera3_jpeg_blob_t;
   1553 
   1554 enum {
   1555     CAMERA3_JPEG_BLOB_ID = 0x00FF
   1556 };
   1557 
   1558 /**********************************************************************
   1559  *
   1560  * Message definitions for the HAL notify() callback.
   1561  *
   1562  * These definitions are used for the HAL notify callback, to signal
   1563  * asynchronous events from the HAL device to the Android framework.
   1564  *
   1565  */
   1566 
   1567 /**
   1568  * camera3_msg_type:
   1569  *
   1570  * Indicates the type of message sent, which specifies which member of the
   1571  * message union is valid.
   1572  *
   1573  */
   1574 typedef enum camera3_msg_type {
   1575     /**
   1576      * An error has occurred. camera3_notify_msg.message.error contains the
   1577      * error information.
   1578      */
   1579     CAMERA3_MSG_ERROR = 1,
   1580 
   1581     /**
   1582      * The exposure of a given request has
   1583      * begun. camera3_notify_msg.message.shutter contains the information
   1584      * the capture.
   1585      */
   1586     CAMERA3_MSG_SHUTTER = 2,
   1587 
   1588     /**
   1589      * Number of framework message types
   1590      */
   1591     CAMERA3_NUM_MESSAGES
   1592 
   1593 } camera3_msg_type_t;
   1594 
   1595 /**
   1596  * Defined error codes for CAMERA_MSG_ERROR
   1597  */
   1598 typedef enum camera3_error_msg_code {
   1599     /**
   1600      * A serious failure occured. No further frames or buffer streams will
   1601      * be produced by the device. Device should be treated as closed. The
   1602      * client must reopen the device to use it again. The frame_number field
   1603      * is unused.
   1604      */
   1605     CAMERA3_MSG_ERROR_DEVICE = 1,
   1606 
   1607     /**
   1608      * An error has occurred in processing a request. No output (metadata or
   1609      * buffers) will be produced for this request. The frame_number field
   1610      * specifies which request has been dropped. Subsequent requests are
   1611      * unaffected, and the device remains operational.
   1612      */
   1613     CAMERA3_MSG_ERROR_REQUEST = 2,
   1614 
   1615     /**
   1616      * An error has occurred in producing an output result metadata buffer
   1617      * for a request, but output stream buffers for it will still be
   1618      * available. Subsequent requests are unaffected, and the device remains
   1619      * operational.  The frame_number field specifies the request for which
   1620      * result metadata won't be available.
   1621      */
   1622     CAMERA3_MSG_ERROR_RESULT = 3,
   1623 
   1624     /**
   1625      * An error has occurred in placing an output buffer into a stream for a
   1626      * request. The frame metadata and other buffers may still be
   1627      * available. Subsequent requests are unaffected, and the device remains
   1628      * operational. The frame_number field specifies the request for which the
   1629      * buffer was dropped, and error_stream contains a pointer to the stream
   1630      * that dropped the frame.u
   1631      */
   1632     CAMERA3_MSG_ERROR_BUFFER = 4,
   1633 
   1634     /**
   1635      * Number of error types
   1636      */
   1637     CAMERA3_MSG_NUM_ERRORS
   1638 
   1639 } camera3_error_msg_code_t;
   1640 
   1641 /**
   1642  * camera3_error_msg_t:
   1643  *
   1644  * Message contents for CAMERA3_MSG_ERROR
   1645  */
   1646 typedef struct camera3_error_msg {
   1647     /**
   1648      * Frame number of the request the error applies to. 0 if the frame number
   1649      * isn't applicable to the error.
   1650      */
   1651     uint32_t frame_number;
   1652 
   1653     /**
   1654      * Pointer to the stream that had a failure. NULL if the stream isn't
   1655      * applicable to the error.
   1656      */
   1657     camera3_stream_t *error_stream;
   1658 
   1659     /**
   1660      * The code for this error; one of the CAMERA_MSG_ERROR enum values.
   1661      */
   1662     int error_code;
   1663 
   1664 } camera3_error_msg_t;
   1665 
   1666 /**
   1667  * camera3_shutter_msg_t:
   1668  *
   1669  * Message contents for CAMERA3_MSG_SHUTTER
   1670  */
   1671 typedef struct camera3_shutter_msg {
   1672     /**
   1673      * Frame number of the request that has begun exposure
   1674      */
   1675     uint32_t frame_number;
   1676 
   1677     /**
   1678      * Timestamp for the start of capture. This must match the capture result
   1679      * metadata's sensor exposure start timestamp.
   1680      */
   1681     uint64_t timestamp;
   1682 
   1683 } camera3_shutter_msg_t;
   1684 
   1685 /**
   1686  * camera3_notify_msg_t:
   1687  *
   1688  * The message structure sent to camera3_callback_ops_t.notify()
   1689  */
   1690 typedef struct camera3_notify_msg {
   1691 
   1692     /**
   1693      * The message type. One of camera3_notify_msg_type, or a private extension.
   1694      */
   1695     int type;
   1696 
   1697     union {
   1698         /**
   1699          * Error message contents. Valid if type is CAMERA3_MSG_ERROR
   1700          */
   1701         camera3_error_msg_t error;
   1702 
   1703         /**
   1704          * Shutter message contents. Valid if type is CAMERA3_MSG_SHUTTER
   1705          */
   1706         camera3_shutter_msg_t shutter;
   1707 
   1708         /**
   1709          * Generic message contents. Used to ensure a minimum size for custom
   1710          * message types.
   1711          */
   1712         uint8_t generic[32];
   1713     } message;
   1714 
   1715 } camera3_notify_msg_t;
   1716 
   1717 /**********************************************************************
   1718  *
   1719  * Capture request/result definitions for the HAL process_capture_request()
   1720  * method, and the process_capture_result() callback.
   1721  *
   1722  */
   1723 
   1724 /**
   1725  * camera3_request_template_t:
   1726  *
   1727  * Available template types for
   1728  * camera3_device_ops.construct_default_request_settings()
   1729  */
   1730 typedef enum camera3_request_template {
   1731     /**
   1732      * Standard camera preview operation with 3A on auto.
   1733      */
   1734     CAMERA3_TEMPLATE_PREVIEW = 1,
   1735 
   1736     /**
   1737      * Standard camera high-quality still capture with 3A and flash on auto.
   1738      */
   1739     CAMERA3_TEMPLATE_STILL_CAPTURE = 2,
   1740 
   1741     /**
   1742      * Standard video recording plus preview with 3A on auto, torch off.
   1743      */
   1744     CAMERA3_TEMPLATE_VIDEO_RECORD = 3,
   1745 
   1746     /**
   1747      * High-quality still capture while recording video. Application will
   1748      * include preview, video record, and full-resolution YUV or JPEG streams in
   1749      * request. Must not cause stuttering on video stream. 3A on auto.
   1750      */
   1751     CAMERA3_TEMPLATE_VIDEO_SNAPSHOT = 4,
   1752 
   1753     /**
   1754      * Zero-shutter-lag mode. Application will request preview and
   1755      * full-resolution data for each frame, and reprocess it to JPEG when a
   1756      * still image is requested by user. Settings should provide highest-quality
   1757      * full-resolution images without compromising preview frame rate. 3A on
   1758      * auto.
   1759      */
   1760     CAMERA3_TEMPLATE_ZERO_SHUTTER_LAG = 5,
   1761 
   1762     /**
   1763      * A basic template for direct application control of capture
   1764      * parameters. All automatic control is disabled (auto-exposure, auto-white
   1765      * balance, auto-focus), and post-processing parameters are set to preview
   1766      * quality. The manual capture parameters (exposure, sensitivity, etc.)
   1767      * are set to reasonable defaults, but should be overridden by the
   1768      * application depending on the intended use case.
   1769      */
   1770     CAMERA3_TEMPLATE_MANUAL = 6,
   1771 
   1772     /* Total number of templates */
   1773     CAMERA3_TEMPLATE_COUNT,
   1774 
   1775     /**
   1776      * First value for vendor-defined request templates
   1777      */
   1778     CAMERA3_VENDOR_TEMPLATE_START = 0x40000000
   1779 
   1780 } camera3_request_template_t;
   1781 
   1782 /**
   1783  * camera3_capture_request_t:
   1784  *
   1785  * A single request for image capture/buffer reprocessing, sent to the Camera
   1786  * HAL device by the framework in process_capture_request().
   1787  *
   1788  * The request contains the settings to be used for this capture, and the set of
   1789  * output buffers to write the resulting image data in. It may optionally
   1790  * contain an input buffer, in which case the request is for reprocessing that
   1791  * input buffer instead of capturing a new image with the camera sensor. The
   1792  * capture is identified by the frame_number.
   1793  *
   1794  * In response, the camera HAL device must send a camera3_capture_result
   1795  * structure asynchronously to the framework, using the process_capture_result()
   1796  * callback.
   1797  */
   1798 typedef struct camera3_capture_request {
   1799     /**
   1800      * The frame number is an incrementing integer set by the framework to
   1801      * uniquely identify this capture. It needs to be returned in the result
   1802      * call, and is also used to identify the request in asynchronous
   1803      * notifications sent to camera3_callback_ops_t.notify().
   1804      */
   1805     uint32_t frame_number;
   1806 
   1807     /**
   1808      * The settings buffer contains the capture and processing parameters for
   1809      * the request. As a special case, a NULL settings buffer indicates that the
   1810      * settings are identical to the most-recently submitted capture request. A
   1811      * NULL buffer cannot be used as the first submitted request after a
   1812      * configure_streams() call.
   1813      */
   1814     const camera_metadata_t *settings;
   1815 
   1816     /**
   1817      * The input stream buffer to use for this request, if any.
   1818      *
   1819      * If input_buffer is NULL, then the request is for a new capture from the
   1820      * imager. If input_buffer is valid, the request is for reprocessing the
   1821      * image contained in input_buffer.
   1822      *
   1823      * In the latter case, the HAL must set the release_fence of the
   1824      * input_buffer to a valid sync fence, or to -1 if the HAL does not support
   1825      * sync, before process_capture_request() returns.
   1826      *
   1827      * The HAL is required to wait on the acquire sync fence of the input buffer
   1828      * before accessing it.
   1829      *
   1830      * <= CAMERA_DEVICE_API_VERSION_3_1:
   1831      *
   1832      * Any input buffer included here will have been registered with the HAL
   1833      * through register_stream_buffers() before its inclusion in a request.
   1834      *
   1835      * >= CAMERA_DEVICE_API_VERSION_3_2:
   1836      *
   1837      * The buffers will not have been pre-registered with the HAL.
   1838      * Subsequent requests may reuse buffers, or provide entirely new buffers.
   1839      */
   1840     camera3_stream_buffer_t *input_buffer;
   1841 
   1842     /**
   1843      * The number of output buffers for this capture request. Must be at least
   1844      * 1.
   1845      */
   1846     uint32_t num_output_buffers;
   1847 
   1848     /**
   1849      * An array of num_output_buffers stream buffers, to be filled with image
   1850      * data from this capture/reprocess. The HAL must wait on the acquire fences
   1851      * of each stream buffer before writing to them.
   1852      *
   1853      * The HAL takes ownership of the actual buffer_handle_t entries in
   1854      * output_buffers; the framework does not access them until they are
   1855      * returned in a camera3_capture_result_t.
   1856      *
   1857      * <= CAMERA_DEVICE_API_VERSION_3_1:
   1858      *
   1859      * All the buffers included  here will have been registered with the HAL
   1860      * through register_stream_buffers() before their inclusion in a request.
   1861      *
   1862      * >= CAMERA_DEVICE_API_VERSION_3_2:
   1863      *
   1864      * Any or all of the buffers included here may be brand new in this
   1865      * request (having never before seen by the HAL).
   1866      */
   1867     const camera3_stream_buffer_t *output_buffers;
   1868 
   1869 } camera3_capture_request_t;
   1870 
   1871 /**
   1872  * camera3_capture_result_t:
   1873  *
   1874  * The result of a single capture/reprocess by the camera HAL device. This is
   1875  * sent to the framework asynchronously with process_capture_result(), in
   1876  * response to a single capture request sent to the HAL with
   1877  * process_capture_request(). Multiple process_capture_result() calls may be
   1878  * performed by the HAL for each request.
   1879  *
   1880  * Each call, all with the same frame
   1881  * number, may contain some subset of the output buffers, and/or the result
   1882  * metadata. The metadata may only be provided once for a given frame number;
   1883  * all other calls must set the result metadata to NULL.
   1884  *
   1885  * The result structure contains the output metadata from this capture, and the
   1886  * set of output buffers that have been/will be filled for this capture. Each
   1887  * output buffer may come with a release sync fence that the framework will wait
   1888  * on before reading, in case the buffer has not yet been filled by the HAL.
   1889  *
   1890  * >= CAMERA_DEVICE_API_VERSION_3_2:
   1891  *
   1892  * The metadata may be provided multiple times for a single frame number. The
   1893  * framework will accumulate together the final result set by combining each
   1894  * partial result together into the total result set.
   1895  *
   1896  * If an input buffer is given in a request, the HAL must return it in one of
   1897  * the process_capture_result calls, and the call may be to just return the input
   1898  * buffer, without metadata and output buffers; the sync fences must be handled
   1899  * the same way they are done for output buffers.
   1900  *
   1901  *
   1902  * Performance considerations:
   1903  *
   1904  * Applications will also receive these partial results immediately, so sending
   1905  * partial results is a highly recommended performance optimization to avoid
   1906  * the total pipeline latency before sending the results for what is known very
   1907  * early on in the pipeline.
   1908  *
   1909  * A typical use case might be calculating the AF state halfway through the
   1910  * pipeline; by sending the state back to the framework immediately, we get a
   1911  * 50% performance increase and perceived responsiveness of the auto-focus.
   1912  *
   1913  */
   1914 typedef struct camera3_capture_result {
   1915     /**
   1916      * The frame number is an incrementing integer set by the framework in the
   1917      * submitted request to uniquely identify this capture. It is also used to
   1918      * identify the request in asynchronous notifications sent to
   1919      * camera3_callback_ops_t.notify().
   1920     */
   1921     uint32_t frame_number;
   1922 
   1923     /**
   1924      * The result metadata for this capture. This contains information about the
   1925      * final capture parameters, the state of the capture and post-processing
   1926      * hardware, the state of the 3A algorithms, if enabled, and the output of
   1927      * any enabled statistics units.
   1928      *
   1929      * Only one call to process_capture_result() with a given frame_number may
   1930      * include the result metadata. All other calls for the same frame_number
   1931      * must set this to NULL.
   1932      *
   1933      * If there was an error producing the result metadata, result must be an
   1934      * empty metadata buffer, and notify() must be called with ERROR_RESULT.
   1935      *
   1936      * >= CAMERA_DEVICE_API_VERSION_3_2:
   1937      *
   1938      * Multiple calls to process_capture_result() with a given frame_number
   1939      * may include the result metadata.
   1940      *
   1941      * Partial metadata submitted should not include any metadata key returned
   1942      * in a previous partial result for a given frame. Each new partial result
   1943      * for that frame must also set a distinct partial_result value.
   1944      *
   1945      * If notify has been called with ERROR_RESULT, all further partial
   1946      * results for that frame are ignored by the framework.
   1947      */
   1948     const camera_metadata_t *result;
   1949 
   1950     /**
   1951      * The number of output buffers returned in this result structure. Must be
   1952      * less than or equal to the matching capture request's count. If this is
   1953      * less than the buffer count in the capture request, at least one more call
   1954      * to process_capture_result with the same frame_number must be made, to
   1955      * return the remaining output buffers to the framework. This may only be
   1956      * zero if the structure includes valid result metadata or an input buffer
   1957      * is returned in this result.
   1958      */
   1959     uint32_t num_output_buffers;
   1960 
   1961     /**
   1962      * The handles for the output stream buffers for this capture. They may not
   1963      * yet be filled at the time the HAL calls process_capture_result(); the
   1964      * framework will wait on the release sync fences provided by the HAL before
   1965      * reading the buffers.
   1966      *
   1967      * The HAL must set the stream buffer's release sync fence to a valid sync
   1968      * fd, or to -1 if the buffer has already been filled.
   1969      *
   1970      * If the HAL encounters an error while processing the buffer, and the
   1971      * buffer is not filled, the buffer's status field must be set to
   1972      * CAMERA3_BUFFER_STATUS_ERROR. If the HAL did not wait on the acquire fence
   1973      * before encountering the error, the acquire fence should be copied into
   1974      * the release fence, to allow the framework to wait on the fence before
   1975      * reusing the buffer.
   1976      *
   1977      * The acquire fence must be set to -1 for all output buffers.  If
   1978      * num_output_buffers is zero, this may be NULL. In that case, at least one
   1979      * more process_capture_result call must be made by the HAL to provide the
   1980      * output buffers.
   1981      *
   1982      * When process_capture_result is called with a new buffer for a frame,
   1983      * all previous frames' buffers for that corresponding stream must have been
   1984      * already delivered (the fences need not have yet been signaled).
   1985      *
   1986      * >= CAMERA_DEVICE_API_VERSION_3_2:
   1987      *
   1988      * Gralloc buffers for a frame may be sent to framework before the
   1989      * corresponding SHUTTER-notify.
   1990      *
   1991      * Performance considerations:
   1992      *
   1993      * Buffers delivered to the framework will not be dispatched to the
   1994      * application layer until a start of exposure timestamp has been received
   1995      * via a SHUTTER notify() call. It is highly recommended to
   1996      * dispatch that call as early as possible.
   1997      */
   1998      const camera3_stream_buffer_t *output_buffers;
   1999 
   2000      /**
   2001       * >= CAMERA_DEVICE_API_VERSION_3_2:
   2002       *
   2003       * The handle for the input stream buffer for this capture. It may not
   2004       * yet be consumed at the time the HAL calls process_capture_result(); the
   2005       * framework will wait on the release sync fences provided by the HAL before
   2006       * reusing the buffer.
   2007       *
   2008       * The HAL should handle the sync fences the same way they are done for
   2009       * output_buffers.
   2010       *
   2011       * Only one input buffer is allowed to be sent per request. Similarly to
   2012       * output buffers, the ordering of returned input buffers must be
   2013       * maintained by the HAL.
   2014       *
   2015       * Performance considerations:
   2016       *
   2017       * The input buffer should be returned as early as possible. If the HAL
   2018       * supports sync fences, it can call process_capture_result to hand it back
   2019       * with sync fences being set appropriately. If the sync fences are not
   2020       * supported, the buffer can only be returned when it is consumed, which
   2021       * may take long time; the HAL may choose to copy this input buffer to make
   2022       * the buffer return sooner.
   2023       */
   2024       const camera3_stream_buffer_t *input_buffer;
   2025 
   2026      /**
   2027       * >= CAMERA_DEVICE_API_VERSION_3_2:
   2028       *
   2029       * In order to take advantage of partial results, the HAL must set the
   2030       * static metadata android.request.partialResultCount to the number of
   2031       * partial results it will send for each frame.
   2032       *
   2033       * Each new capture result with a partial result must set
   2034       * this field (partial_result) to a distinct inclusive value between
   2035       * 1 and android.request.partialResultCount.
   2036       *
   2037       * HALs not wishing to take advantage of this feature must not
   2038       * set an android.request.partialResultCount or partial_result to a value
   2039       * other than 1.
   2040       *
   2041       * This value must be set to 0 when a capture result contains buffers only
   2042       * and no metadata.
   2043       */
   2044      uint32_t partial_result;
   2045 
   2046 } camera3_capture_result_t;
   2047 
   2048 /**********************************************************************
   2049  *
   2050  * Callback methods for the HAL to call into the framework.
   2051  *
   2052  * These methods are used to return metadata and image buffers for a completed
   2053  * or failed captures, and to notify the framework of asynchronous events such
   2054  * as errors.
   2055  *
   2056  * The framework will not call back into the HAL from within these callbacks,
   2057  * and these calls will not block for extended periods.
   2058  *
   2059  */
   2060 typedef struct camera3_callback_ops {
   2061 
   2062     /**
   2063      * process_capture_result:
   2064      *
   2065      * Send results from a completed capture to the framework.
   2066      * process_capture_result() may be invoked multiple times by the HAL in
   2067      * response to a single capture request. This allows, for example, the
   2068      * metadata and low-resolution buffers to be returned in one call, and
   2069      * post-processed JPEG buffers in a later call, once it is available. Each
   2070      * call must include the frame number of the request it is returning
   2071      * metadata or buffers for.
   2072      *
   2073      * A component (buffer or metadata) of the complete result may only be
   2074      * included in one process_capture_result call. A buffer for each stream,
   2075      * and the result metadata, must be returned by the HAL for each request in
   2076      * one of the process_capture_result calls, even in case of errors producing
   2077      * some of the output. A call to process_capture_result() with neither
   2078      * output buffers or result metadata is not allowed.
   2079      *
   2080      * The order of returning metadata and buffers for a single result does not
   2081      * matter, but buffers for a given stream must be returned in FIFO order. So
   2082      * the buffer for request 5 for stream A must always be returned before the
   2083      * buffer for request 6 for stream A. This also applies to the result
   2084      * metadata; the metadata for request 5 must be returned before the metadata
   2085      * for request 6.
   2086      *
   2087      * However, different streams are independent of each other, so it is
   2088      * acceptable and expected that the buffer for request 5 for stream A may be
   2089      * returned after the buffer for request 6 for stream B is. And it is
   2090      * acceptable that the result metadata for request 6 for stream B is
   2091      * returned before the buffer for request 5 for stream A is.
   2092      *
   2093      * The HAL retains ownership of result structure, which only needs to be
   2094      * valid to access during this call. The framework will copy whatever it
   2095      * needs before this call returns.
   2096      *
   2097      * The output buffers do not need to be filled yet; the framework will wait
   2098      * on the stream buffer release sync fence before reading the buffer
   2099      * data. Therefore, this method should be called by the HAL as soon as
   2100      * possible, even if some or all of the output buffers are still in
   2101      * being filled. The HAL must include valid release sync fences into each
   2102      * output_buffers stream buffer entry, or -1 if that stream buffer is
   2103      * already filled.
   2104      *
   2105      * If the result buffer cannot be constructed for a request, the HAL should
   2106      * return an empty metadata buffer, but still provide the output buffers and
   2107      * their sync fences. In addition, notify() must be called with an
   2108      * ERROR_RESULT message.
   2109      *
   2110      * If an output buffer cannot be filled, its status field must be set to
   2111      * STATUS_ERROR. In addition, notify() must be called with a ERROR_BUFFER
   2112      * message.
   2113      *
   2114      * If the entire capture has failed, then this method still needs to be
   2115      * called to return the output buffers to the framework. All the buffer
   2116      * statuses should be STATUS_ERROR, and the result metadata should be an
   2117      * empty buffer. In addition, notify() must be called with a ERROR_REQUEST
   2118      * message. In this case, individual ERROR_RESULT/ERROR_BUFFER messages
   2119      * should not be sent.
   2120      *
   2121      * Performance requirements:
   2122      *
   2123      * This is a non-blocking call. The framework will return this call in 5ms.
   2124      *
   2125      * The pipeline latency (see S7 for definition) should be less than or equal to
   2126      * 4 frame intervals, and must be less than or equal to 8 frame intervals.
   2127      *
   2128      */
   2129     void (*process_capture_result)(const struct camera3_callback_ops *,
   2130             const camera3_capture_result_t *result);
   2131 
   2132     /**
   2133      * notify:
   2134      *
   2135      * Asynchronous notification callback from the HAL, fired for various
   2136      * reasons. Only for information independent of frame capture, or that
   2137      * require specific timing. The ownership of the message structure remains
   2138      * with the HAL, and the msg only needs to be valid for the duration of this
   2139      * call.
   2140      *
   2141      * Multiple threads may call notify() simultaneously.
   2142      *
   2143      * <= CAMERA_DEVICE_API_VERSION_3_1:
   2144      *
   2145      * The notification for the start of exposure for a given request must be
   2146      * sent by the HAL before the first call to process_capture_result() for
   2147      * that request is made.
   2148      *
   2149      * >= CAMERA_DEVICE_API_VERSION_3_2:
   2150      *
   2151      * Buffers delivered to the framework will not be dispatched to the
   2152      * application layer until a start of exposure timestamp has been received
   2153      * via a SHUTTER notify() call. It is highly recommended to
   2154      * dispatch this call as early as possible.
   2155      *
   2156      * ------------------------------------------------------------------------
   2157      * Performance requirements:
   2158      *
   2159      * This is a non-blocking call. The framework will return this call in 5ms.
   2160      */
   2161     void (*notify)(const struct camera3_callback_ops *,
   2162             const camera3_notify_msg_t *msg);
   2163 
   2164 } camera3_callback_ops_t;
   2165 
   2166 /**********************************************************************
   2167  *
   2168  * Camera device operations
   2169  *
   2170  */
   2171 typedef struct camera3_device_ops {
   2172 
   2173     /**
   2174      * initialize:
   2175      *
   2176      * One-time initialization to pass framework callback function pointers to
   2177      * the HAL. Will be called once after a successful open() call, before any
   2178      * other functions are called on the camera3_device_ops structure.
   2179      *
   2180      * Performance requirements:
   2181      *
   2182      * This should be a non-blocking call. The HAL should return from this call
   2183      * in 5ms, and must return from this call in 10ms.
   2184      *
   2185      * Return values:
   2186      *
   2187      *  0:     On successful initialization
   2188      *
   2189      * -ENODEV: If initialization fails. Only close() can be called successfully
   2190      *          by the framework after this.
   2191      */
   2192     int (*initialize)(const struct camera3_device *,
   2193             const camera3_callback_ops_t *callback_ops);
   2194 
   2195     /**********************************************************************
   2196      * Stream management
   2197      */
   2198 
   2199     /**
   2200      * configure_streams:
   2201      *
   2202      * CAMERA_DEVICE_API_VERSION_3_0 only:
   2203      *
   2204      * Reset the HAL camera device processing pipeline and set up new input and
   2205      * output streams. This call replaces any existing stream configuration with
   2206      * the streams defined in the stream_list. This method will be called at
   2207      * least once after initialize() before a request is submitted with
   2208      * process_capture_request().
   2209      *
   2210      * The stream_list must contain at least one output-capable stream, and may
   2211      * not contain more than one input-capable stream.
   2212      *
   2213      * The stream_list may contain streams that are also in the currently-active
   2214      * set of streams (from the previous call to configure_stream()). These
   2215      * streams will already have valid values for usage, max_buffers, and the
   2216      * private pointer.
   2217      *
   2218      * If such a stream has already had its buffers registered,
   2219      * register_stream_buffers() will not be called again for the stream, and
   2220      * buffers from the stream can be immediately included in input requests.
   2221      *
   2222      * If the HAL needs to change the stream configuration for an existing
   2223      * stream due to the new configuration, it may rewrite the values of usage
   2224      * and/or max_buffers during the configure call.
   2225      *
   2226      * The framework will detect such a change, and will then reallocate the
   2227      * stream buffers, and call register_stream_buffers() again before using
   2228      * buffers from that stream in a request.
   2229      *
   2230      * If a currently-active stream is not included in stream_list, the HAL may
   2231      * safely remove any references to that stream. It will not be reused in a
   2232      * later configure() call by the framework, and all the gralloc buffers for
   2233      * it will be freed after the configure_streams() call returns.
   2234      *
   2235      * The stream_list structure is owned by the framework, and may not be
   2236      * accessed once this call completes. The address of an individual
   2237      * camera3_stream_t structure will remain valid for access by the HAL until
   2238      * the end of the first configure_stream() call which no longer includes
   2239      * that camera3_stream_t in the stream_list argument. The HAL may not change
   2240      * values in the stream structure outside of the private pointer, except for
   2241      * the usage and max_buffers members during the configure_streams() call
   2242      * itself.
   2243      *
   2244      * If the stream is new, the usage, max_buffer, and private pointer fields
   2245      * of the stream structure will all be set to 0. The HAL device must set
   2246      * these fields before the configure_streams() call returns. These fields
   2247      * are then used by the framework and the platform gralloc module to
   2248      * allocate the gralloc buffers for each stream.
   2249      *
   2250      * Before such a new stream can have its buffers included in a capture
   2251      * request, the framework will call register_stream_buffers() with that
   2252      * stream. However, the framework is not required to register buffers for
   2253      * _all_ streams before submitting a request. This allows for quick startup
   2254      * of (for example) a preview stream, with allocation for other streams
   2255      * happening later or concurrently.
   2256      *
   2257      * ------------------------------------------------------------------------
   2258      * CAMERA_DEVICE_API_VERSION_3_1 only:
   2259      *
   2260      * Reset the HAL camera device processing pipeline and set up new input and
   2261      * output streams. This call replaces any existing stream configuration with
   2262      * the streams defined in the stream_list. This method will be called at
   2263      * least once after initialize() before a request is submitted with
   2264      * process_capture_request().
   2265      *
   2266      * The stream_list must contain at least one output-capable stream, and may
   2267      * not contain more than one input-capable stream.
   2268      *
   2269      * The stream_list may contain streams that are also in the currently-active
   2270      * set of streams (from the previous call to configure_stream()). These
   2271      * streams will already have valid values for usage, max_buffers, and the
   2272      * private pointer.
   2273      *
   2274      * If such a stream has already had its buffers registered,
   2275      * register_stream_buffers() will not be called again for the stream, and
   2276      * buffers from the stream can be immediately included in input requests.
   2277      *
   2278      * If the HAL needs to change the stream configuration for an existing
   2279      * stream due to the new configuration, it may rewrite the values of usage
   2280      * and/or max_buffers during the configure call.
   2281      *
   2282      * The framework will detect such a change, and will then reallocate the
   2283      * stream buffers, and call register_stream_buffers() again before using
   2284      * buffers from that stream in a request.
   2285      *
   2286      * If a currently-active stream is not included in stream_list, the HAL may
   2287      * safely remove any references to that stream. It will not be reused in a
   2288      * later configure() call by the framework, and all the gralloc buffers for
   2289      * it will be freed after the configure_streams() call returns.
   2290      *
   2291      * The stream_list structure is owned by the framework, and may not be
   2292      * accessed once this call completes. The address of an individual
   2293      * camera3_stream_t structure will remain valid for access by the HAL until
   2294      * the end of the first configure_stream() call which no longer includes
   2295      * that camera3_stream_t in the stream_list argument. The HAL may not change
   2296      * values in the stream structure outside of the private pointer, except for
   2297      * the usage and max_buffers members during the configure_streams() call
   2298      * itself.
   2299      *
   2300      * If the stream is new, max_buffer, and private pointer fields of the
   2301      * stream structure will all be set to 0. The usage will be set to the
   2302      * consumer usage flags. The HAL device must set these fields before the
   2303      * configure_streams() call returns. These fields are then used by the
   2304      * framework and the platform gralloc module to allocate the gralloc
   2305      * buffers for each stream.
   2306      *
   2307      * Before such a new stream can have its buffers included in a capture
   2308      * request, the framework will call register_stream_buffers() with that
   2309      * stream. However, the framework is not required to register buffers for
   2310      * _all_ streams before submitting a request. This allows for quick startup
   2311      * of (for example) a preview stream, with allocation for other streams
   2312      * happening later or concurrently.
   2313      *
   2314      * ------------------------------------------------------------------------
   2315      * >= CAMERA_DEVICE_API_VERSION_3_2:
   2316      *
   2317      * Reset the HAL camera device processing pipeline and set up new input and
   2318      * output streams. This call replaces any existing stream configuration with
   2319      * the streams defined in the stream_list. This method will be called at
   2320      * least once after initialize() before a request is submitted with
   2321      * process_capture_request().
   2322      *
   2323      * The stream_list must contain at least one output-capable stream, and may
   2324      * not contain more than one input-capable stream.
   2325      *
   2326      * The stream_list may contain streams that are also in the currently-active
   2327      * set of streams (from the previous call to configure_stream()). These
   2328      * streams will already have valid values for usage, max_buffers, and the
   2329      * private pointer.
   2330      *
   2331      * If the HAL needs to change the stream configuration for an existing
   2332      * stream due to the new configuration, it may rewrite the values of usage
   2333      * and/or max_buffers during the configure call.
   2334      *
   2335      * The framework will detect such a change, and may then reallocate the
   2336      * stream buffers before using buffers from that stream in a request.
   2337      *
   2338      * If a currently-active stream is not included in stream_list, the HAL may
   2339      * safely remove any references to that stream. It will not be reused in a
   2340      * later configure() call by the framework, and all the gralloc buffers for
   2341      * it will be freed after the configure_streams() call returns.
   2342      *
   2343      * The stream_list structure is owned by the framework, and may not be
   2344      * accessed once this call completes. The address of an individual
   2345      * camera3_stream_t structure will remain valid for access by the HAL until
   2346      * the end of the first configure_stream() call which no longer includes
   2347      * that camera3_stream_t in the stream_list argument. The HAL may not change
   2348      * values in the stream structure outside of the private pointer, except for
   2349      * the usage and max_buffers members during the configure_streams() call
   2350      * itself.
   2351      *
   2352      * If the stream is new, max_buffer, and private pointer fields of the
   2353      * stream structure will all be set to 0. The usage will be set to the
   2354      * consumer usage flags. The HAL device must set these fields before the
   2355      * configure_streams() call returns. These fields are then used by the
   2356      * framework and the platform gralloc module to allocate the gralloc
   2357      * buffers for each stream.
   2358      *
   2359      * Newly allocated buffers may be included in a capture request at any time
   2360      * by the framework. Once a gralloc buffer is returned to the framework
   2361      * with process_capture_result (and its respective release_fence has been
   2362      * signaled) the framework may free or reuse it at any time.
   2363      *
   2364      * ------------------------------------------------------------------------
   2365      *
   2366      * Preconditions:
   2367      *
   2368      * The framework will only call this method when no captures are being
   2369      * processed. That is, all results have been returned to the framework, and
   2370      * all in-flight input and output buffers have been returned and their
   2371      * release sync fences have been signaled by the HAL. The framework will not
   2372      * submit new requests for capture while the configure_streams() call is
   2373      * underway.
   2374      *
   2375      * Postconditions:
   2376      *
   2377      * The HAL device must configure itself to provide maximum possible output
   2378      * frame rate given the sizes and formats of the output streams, as
   2379      * documented in the camera device's static metadata.
   2380      *
   2381      * Performance requirements:
   2382      *
   2383      * This call is expected to be heavyweight and possibly take several hundred
   2384      * milliseconds to complete, since it may require resetting and
   2385      * reconfiguring the image sensor and the camera processing pipeline.
   2386      * Nevertheless, the HAL device should attempt to minimize the
   2387      * reconfiguration delay to minimize the user-visible pauses during
   2388      * application operational mode changes (such as switching from still
   2389      * capture to video recording).
   2390      *
   2391      * The HAL should return from this call in 500ms, and must return from this
   2392      * call in 1000ms.
   2393      *
   2394      * Return values:
   2395      *
   2396      *  0:      On successful stream configuration
   2397      *
   2398      * -EINVAL: If the requested stream configuration is invalid. Some examples
   2399      *          of invalid stream configurations include:
   2400      *
   2401      *          - Including more than 1 input-capable stream (INPUT or
   2402      *            BIDIRECTIONAL)
   2403      *
   2404      *          - Not including any output-capable streams (OUTPUT or
   2405      *            BIDIRECTIONAL)
   2406      *
   2407      *          - Including streams with unsupported formats, or an unsupported
   2408      *            size for that format.
   2409      *
   2410      *          - Including too many output streams of a certain format.
   2411      *
   2412      *          Note that the framework submitting an invalid stream
   2413      *          configuration is not normal operation, since stream
   2414      *          configurations are checked before configure. An invalid
   2415      *          configuration means that a bug exists in the framework code, or
   2416      *          there is a mismatch between the HAL's static metadata and the
   2417      *          requirements on streams.
   2418      *
   2419      * -ENODEV: If there has been a fatal error and the device is no longer
   2420      *          operational. Only close() can be called successfully by the
   2421      *          framework after this error is returned.
   2422      */
   2423     int (*configure_streams)(const struct camera3_device *,
   2424             camera3_stream_configuration_t *stream_list);
   2425 
   2426     /**
   2427      * register_stream_buffers:
   2428      *
   2429      * >= CAMERA_DEVICE_API_VERSION_3_2:
   2430      *
   2431      * DEPRECATED. This will not be called and must be set to NULL.
   2432      *
   2433      * <= CAMERA_DEVICE_API_VERSION_3_1:
   2434      *
   2435      * Register buffers for a given stream with the HAL device. This method is
   2436      * called by the framework after a new stream is defined by
   2437      * configure_streams, and before buffers from that stream are included in a
   2438      * capture request. If the same stream is listed in a subsequent
   2439      * configure_streams() call, register_stream_buffers will _not_ be called
   2440      * again for that stream.
   2441      *
   2442      * The framework does not need to register buffers for all configured
   2443      * streams before it submits the first capture request. This allows quick
   2444      * startup for preview (or similar use cases) while other streams are still
   2445      * being allocated.
   2446      *
   2447      * This method is intended to allow the HAL device to map or otherwise
   2448      * prepare the buffers for later use. The buffers passed in will already be
   2449      * locked for use. At the end of the call, all the buffers must be ready to
   2450      * be returned to the stream.  The buffer_set argument is only valid for the
   2451      * duration of this call.
   2452      *
   2453      * If the stream format was set to HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED,
   2454      * the camera HAL should inspect the passed-in buffers here to determine any
   2455      * platform-private pixel format information.
   2456      *
   2457      * Performance requirements:
   2458      *
   2459      * This should be a non-blocking call. The HAL should return from this call
   2460      * in 1ms, and must return from this call in 5ms.
   2461      *
   2462      * Return values:
   2463      *
   2464      *  0:      On successful registration of the new stream buffers
   2465      *
   2466      * -EINVAL: If the stream_buffer_set does not refer to a valid active
   2467      *          stream, or if the buffers array is invalid.
   2468      *
   2469      * -ENOMEM: If there was a failure in registering the buffers. The framework
   2470      *          must consider all the stream buffers to be unregistered, and can
   2471      *          try to register again later.
   2472      *
   2473      * -ENODEV: If there is a fatal error, and the device is no longer
   2474      *          operational. Only close() can be called successfully by the
   2475      *          framework after this error is returned.
   2476      */
   2477     int (*register_stream_buffers)(const struct camera3_device *,
   2478             const camera3_stream_buffer_set_t *buffer_set);
   2479 
   2480     /**********************************************************************
   2481      * Request creation and submission
   2482      */
   2483 
   2484     /**
   2485      * construct_default_request_settings:
   2486      *
   2487      * Create capture settings for standard camera use cases.
   2488      *
   2489      * The device must return a settings buffer that is configured to meet the
   2490      * requested use case, which must be one of the CAMERA3_TEMPLATE_*
   2491      * enums. All request control fields must be included.
   2492      *
   2493      * The HAL retains ownership of this structure, but the pointer to the
   2494      * structure must be valid until the device is closed. The framework and the
   2495      * HAL may not modify the buffer once it is returned by this call. The same
   2496      * buffer may be returned for subsequent calls for the same template, or for
   2497      * other templates.
   2498      *
   2499      * Performance requirements:
   2500      *
   2501      * This should be a non-blocking call. The HAL should return from this call
   2502      * in 1ms, and must return from this call in 5ms.
   2503      *
   2504      * Return values:
   2505      *
   2506      *   Valid metadata: On successful creation of a default settings
   2507      *                   buffer.
   2508      *
   2509      *   NULL:           In case of a fatal error. After this is returned, only
   2510      *                   the close() method can be called successfully by the
   2511      *                   framework.
   2512      */
   2513     const camera_metadata_t* (*construct_default_request_settings)(
   2514             const struct camera3_device *,
   2515             int type);
   2516 
   2517     /**
   2518      * process_capture_request:
   2519      *
   2520      * Send a new capture request to the HAL. The HAL should not return from
   2521      * this call until it is ready to accept the next request to process. Only
   2522      * one call to process_capture_request() will be made at a time by the
   2523      * framework, and the calls will all be from the same thread. The next call
   2524      * to process_capture_request() will be made as soon as a new request and
   2525      * its associated buffers are available. In a normal preview scenario, this
   2526      * means the function will be called again by the framework almost
   2527      * instantly.
   2528      *
   2529      * The actual request processing is asynchronous, with the results of
   2530      * capture being returned by the HAL through the process_capture_result()
   2531      * call. This call requires the result metadata to be available, but output
   2532      * buffers may simply provide sync fences to wait on. Multiple requests are
   2533      * expected to be in flight at once, to maintain full output frame rate.
   2534      *
   2535      * The framework retains ownership of the request structure. It is only
   2536      * guaranteed to be valid during this call. The HAL device must make copies
   2537      * of the information it needs to retain for the capture processing. The HAL
   2538      * is responsible for waiting on and closing the buffers' fences and
   2539      * returning the buffer handles to the framework.
   2540      *
   2541      * The HAL must write the file descriptor for the input buffer's release
   2542      * sync fence into input_buffer->release_fence, if input_buffer is not
   2543      * NULL. If the HAL returns -1 for the input buffer release sync fence, the
   2544      * framework is free to immediately reuse the input buffer. Otherwise, the
   2545      * framework will wait on the sync fence before refilling and reusing the
   2546      * input buffer.
   2547      *
   2548      * >= CAMERA_DEVICE_API_VERSION_3_2:
   2549      *
   2550      * The input/output buffers provided by the framework in each request
   2551      * may be brand new (having never before seen by the HAL).
   2552      *
   2553      * ------------------------------------------------------------------------
   2554      * Performance considerations:
   2555      *
   2556      * Handling a new buffer should be extremely lightweight and there should be
   2557      * no frame rate degradation or frame jitter introduced.
   2558      *
   2559      * This call must return fast enough to ensure that the requested frame
   2560      * rate can be sustained, especially for streaming cases (post-processing
   2561      * quality settings set to FAST). The HAL should return this call in 1
   2562      * frame interval, and must return from this call in 4 frame intervals.
   2563      *
   2564      * Return values:
   2565      *
   2566      *  0:      On a successful start to processing the capture request
   2567      *
   2568      * -EINVAL: If the input is malformed (the settings are NULL when not
   2569      *          allowed, there are 0 output buffers, etc) and capture processing
   2570      *          cannot start. Failures during request processing should be
   2571      *          handled by calling camera3_callback_ops_t.notify(). In case of
   2572      *          this error, the framework will retain responsibility for the
   2573      *          stream buffers' fences and the buffer handles; the HAL should
   2574      *          not close the fences or return these buffers with
   2575      *          process_capture_result.
   2576      *
   2577      * -ENODEV: If the camera device has encountered a serious error. After this
   2578      *          error is returned, only the close() method can be successfully
   2579      *          called by the framework.
   2580      *
   2581      */
   2582     int (*process_capture_request)(const struct camera3_device *,
   2583             camera3_capture_request_t *request);
   2584 
   2585     /**********************************************************************
   2586      * Miscellaneous methods
   2587      */
   2588 
   2589     /**
   2590      * get_metadata_vendor_tag_ops:
   2591      *
   2592      * Get methods to query for vendor extension metadata tag information. The
   2593      * HAL should fill in all the vendor tag operation methods, or leave ops
   2594      * unchanged if no vendor tags are defined.
   2595      *
   2596      * The definition of vendor_tag_query_ops_t can be found in
   2597      * system/media/camera/include/system/camera_metadata.h.
   2598      *
   2599      * >= CAMERA_DEVICE_API_VERSION_3_2:
   2600      *    DEPRECATED. This function has been deprecated and should be set to
   2601      *    NULL by the HAL.  Please implement get_vendor_tag_ops in camera_common.h
   2602      *    instead.
   2603      */
   2604     void (*get_metadata_vendor_tag_ops)(const struct camera3_device*,
   2605             vendor_tag_query_ops_t* ops);
   2606 
   2607     /**
   2608      * dump:
   2609      *
   2610      * Print out debugging state for the camera device. This will be called by
   2611      * the framework when the camera service is asked for a debug dump, which
   2612      * happens when using the dumpsys tool, or when capturing a bugreport.
   2613      *
   2614      * The passed-in file descriptor can be used to write debugging text using
   2615      * dprintf() or write(). The text should be in ASCII encoding only.
   2616      *
   2617      * Performance requirements:
   2618      *
   2619      * This must be a non-blocking call. The HAL should return from this call
   2620      * in 1ms, must return from this call in 10ms. This call must avoid
   2621      * deadlocks, as it may be called at any point during camera operation.
   2622      * Any synchronization primitives used (such as mutex locks or semaphores)
   2623      * should be acquired with a timeout.
   2624      */
   2625     void (*dump)(const struct camera3_device *, int fd);
   2626 
   2627     /**
   2628      * flush:
   2629      *
   2630      * Flush all currently in-process captures and all buffers in the pipeline
   2631      * on the given device. The framework will use this to dump all state as
   2632      * quickly as possible in order to prepare for a configure_streams() call.
   2633      *
   2634      * No buffers are required to be successfully returned, so every buffer
   2635      * held at the time of flush() (whether successfully filled or not) may be
   2636      * returned with CAMERA3_BUFFER_STATUS_ERROR. Note the HAL is still allowed
   2637      * to return valid (CAMERA3_BUFFER_STATUS_OK) buffers during this call,
   2638      * provided they are successfully filled.
   2639      *
   2640      * All requests currently in the HAL are expected to be returned as soon as
   2641      * possible.  Not-in-process requests should return errors immediately. Any
   2642      * interruptible hardware blocks should be stopped, and any uninterruptible
   2643      * blocks should be waited on.
   2644      *
   2645      * More specifically, the HAL must follow below requirements for various cases:
   2646      *
   2647      * 1. For captures that are too late for the HAL to cancel/stop, and will be
   2648      *    completed normally by the HAL; i.e. the HAL can send shutter/notify and
   2649      *    process_capture_result and buffers as normal.
   2650      *
   2651      * 2. For pending requests that have not done any processing, the HAL must call notify
   2652      *    CAMERA3_MSG_ERROR_REQUEST, and return all the output buffers with
   2653      *    process_capture_result in the error state (CAMERA3_BUFFER_STATUS_ERROR).
   2654      *    The HAL must not place the release fence into an error state, instead,
   2655      *    the release fences must be set to the acquire fences passed by the framework,
   2656      *    or -1 if they have been waited on by the HAL already. This is also the path
   2657      *    to follow for any captures for which the HAL already called notify() with
   2658      *    CAMERA3_MSG_SHUTTER but won't be producing any metadata/valid buffers for.
   2659      *    After CAMERA3_MSG_ERROR_REQUEST, for a given frame, only process_capture_results with
   2660      *    buffers in CAMERA3_BUFFER_STATUS_ERROR are allowed. No further notifys or
   2661      *    process_capture_result with non-null metadata is allowed.
   2662      *
   2663      * 3. For partially completed pending requests that will not have all the output
   2664      *    buffers or perhaps missing metadata, the HAL should follow below:
   2665      *
   2666      *    3.1. Call notify with CAMERA3_MSG_ERROR_RESULT if some of the expected result
   2667      *    metadata (i.e. one or more partial metadata) won't be available for the capture.
   2668      *
   2669      *    3.2. Call notify with CAMERA3_MSG_ERROR_BUFFER for every buffer that won't
   2670      *         be produced for the capture.
   2671      *
   2672      *    3.3  Call notify with CAMERA3_MSG_SHUTTER with the capture timestamp before
   2673      *         any buffers/metadata are returned with process_capture_result.
   2674      *
   2675      *    3.4 For captures that will produce some results, the HAL must not call
   2676      *        CAMERA3_MSG_ERROR_REQUEST, since that indicates complete failure.
   2677      *
   2678      *    3.5. Valid buffers/metadata should be passed to the framework as normal.
   2679      *
   2680      *    3.6. Failed buffers should be returned to the framework as described for case 2.
   2681      *         But failed buffers do not have to follow the strict ordering valid buffers do,
   2682      *         and may be out-of-order with respect to valid buffers. For example, if buffers
   2683      *         A, B, C, D, E are sent, D and E are failed, then A, E, B, D, C is an acceptable
   2684      *         return order.
   2685      *
   2686      *    3.7. For fully-missing metadata, calling CAMERA3_MSG_ERROR_RESULT is sufficient, no
   2687      *         need to call process_capture_result with NULL metadata or equivalent.
   2688      *
   2689      * flush() should only return when there are no more outstanding buffers or
   2690      * requests left in the HAL. The framework may call configure_streams (as
   2691      * the HAL state is now quiesced) or may issue new requests.
   2692      *
   2693      * Note that it's sufficient to only support fully-succeeded and fully-failed result cases.
   2694      * However, it is highly desirable to support the partial failure cases as well, as it
   2695      * could help improve the flush call overall performance.
   2696      *
   2697      * Performance requirements:
   2698      *
   2699      * The HAL should return from this call in 100ms, and must return from this
   2700      * call in 1000ms. And this call must not be blocked longer than pipeline
   2701      * latency (see S7 for definition).
   2702      *
   2703      * Version information:
   2704      *
   2705      *   only available if device version >= CAMERA_DEVICE_API_VERSION_3_1.
   2706      *
   2707      * Return values:
   2708      *
   2709      *  0:      On a successful flush of the camera HAL.
   2710      *
   2711      * -EINVAL: If the input is malformed (the device is not valid).
   2712      *
   2713      * -ENODEV: If the camera device has encountered a serious error. After this
   2714      *          error is returned, only the close() method can be successfully
   2715      *          called by the framework.
   2716      */
   2717     int (*flush)(const struct camera3_device *);
   2718 
   2719     /* reserved for future use */
   2720     void *reserved[8];
   2721 } camera3_device_ops_t;
   2722 
   2723 /**********************************************************************
   2724  *
   2725  * Camera device definition
   2726  *
   2727  */
   2728 typedef struct camera3_device {
   2729     /**
   2730      * common.version must equal CAMERA_DEVICE_API_VERSION_3_0 to identify this
   2731      * device as implementing version 3.0 of the camera device HAL.
   2732      *
   2733      * Performance requirements:
   2734      *
   2735      * Camera open (common.module->common.methods->open) should return in 200ms, and must return
   2736      * in 500ms.
   2737      * Camera close (common.close) should return in 200ms, and must return in 500ms.
   2738      *
   2739      */
   2740     hw_device_t common;
   2741     camera3_device_ops_t *ops;
   2742     void *priv;
   2743 } camera3_device_t;
   2744 
   2745 __END_DECLS
   2746 
   2747 #endif /* #ifdef ANDROID_INCLUDE_CAMERA3_H */
   2748