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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 3.0 [ CAMERA_DEVICE_API_VERSION_3_0 ]
     25  *
     26  * EXPERIMENTAL.
     27  *
     28  * Supports the android.hardware.Camera API.
     29  *
     30  * Camera devices that support this version of the HAL must return
     31  * CAMERA_DEVICE_API_VERSION_3_0 in camera_device_t.common.version and in
     32  * camera_info_t.device_version (from camera_module_t.get_camera_info).
     33  *
     34  * Camera modules that may contain version 3.0 devices must implement at least
     35  * version 2.0 of the camera module interface (as defined by
     36  * camera_module_t.common.module_api_version).
     37  *
     38  * See camera_common.h for more versioning details.
     39  *
     40  * Documentation index:
     41  *   S1. Version history
     42  *   S2. Startup and operation sequencing
     43  *   S3. Operational modes
     44  *   S4. 3A modes and state machines
     45  *   S5. Cropping
     46  *   S6. Error management
     47  */
     48 
     49 /**
     50  * S1. Version history:
     51  *
     52  * 1.0: Initial Android camera HAL (Android 4.0) [camera.h]:
     53  *
     54  *   - Converted from C++ CameraHardwareInterface abstraction layer.
     55  *
     56  *   - Supports android.hardware.Camera API.
     57  *
     58  * 2.0: Initial release of expanded-capability HAL (Android 4.2) [camera2.h]:
     59  *
     60  *   - Sufficient for implementing existing android.hardware.Camera API.
     61  *
     62  *   - Allows for ZSL queue in camera service layer
     63  *
     64  *   - Not tested for any new features such manual capture control, Bayer RAW
     65  *     capture, reprocessing of RAW data.
     66  *
     67  * 3.0: First revision of expanded-capability HAL:
     68  *
     69  *   - Major version change since the ABI is completely different. No change to
     70  *     the required hardware capabilities or operational model from 2.0.
     71  *
     72  *   - Reworked input request and stream queue interfaces: Framework calls into
     73  *     HAL with next request and stream buffers already dequeued. Sync framework
     74  *     support is included, necessary for efficient implementations.
     75  *
     76  *   - Moved triggers into requests, most notifications into results.
     77  *
     78  *   - Consolidated all callbacks into framework into one structure, and all
     79  *     setup methods into a single initialize() call.
     80  *
     81  *   - Made stream configuration into a single call to simplify stream
     82  *     management. Bidirectional streams replace STREAM_FROM_STREAM construct.
     83  *
     84  *   - Limited mode semantics for older/limited hardware devices.
     85  */
     86 
     87 /**
     88  * S2. Startup and general expected operation sequence:
     89  *
     90  * 1. Framework calls camera_module_t->common.open(), which returns a
     91  *    hardware_device_t structure.
     92  *
     93  * 2. Framework inspects the hardware_device_t->version field, and instantiates
     94  *    the appropriate handler for that version of the camera hardware device. In
     95  *    case the version is CAMERA_DEVICE_API_VERSION_3_0, the device is cast to
     96  *    a camera3_device_t.
     97  *
     98  * 3. Framework calls camera3_device_t->ops->initialize() with the framework
     99  *    callback function pointers. This will only be called this one time after
    100  *    open(), before any other functions in the ops structure are called.
    101  *
    102  * 4. The framework calls camera3_device_t->ops->configure_streams() with a list
    103  *    of input/output streams to the HAL device.
    104  *
    105  * 5. The framework allocates gralloc buffers and calls
    106  *    camera3_device_t->ops->register_stream_buffers() for at least one of the
    107  *    output streams listed in configure_streams. The same stream is registered
    108  *    only once.
    109  *
    110  * 5. The framework requests default settings for some number of use cases with
    111  *    calls to camera3_device_t->ops->construct_default_request_settings(). This
    112  *    may occur any time after step 3.
    113  *
    114  * 7. The framework constructs and sends the first capture request to the HAL,
    115  *    with settings based on one of the sets of default settings, and with at
    116  *    least one output stream, which has been registered earlier by the
    117  *    framework. This is sent to the HAL with
    118  *    camera3_device_t->ops->process_capture_request(). The HAL must block the
    119  *    return of this call until it is ready for the next request to be sent.
    120  *
    121  * 8. The framework continues to submit requests, and possibly call
    122  *    register_stream_buffers() for not-yet-registered streams, and call
    123  *    construct_default_request_settings to get default settings buffers for
    124  *    other use cases.
    125  *
    126  * 9. When the capture of a request begins (sensor starts exposing for the
    127  *    capture), the HAL calls camera3_callback_ops_t->notify() with the SHUTTER
    128  *    event, including the frame number and the timestamp for start of exposure.
    129  *    This notify call must be made before the first call to
    130  *    process_capture_result() for that frame number.
    131  *
    132  * 10. After some pipeline delay, the HAL begins to return completed captures to
    133  *    the framework with camera3_callback_ops_t->process_capture_result(). These
    134  *    are returned in the same order as the requests were submitted. Multiple
    135  *    requests can be in flight at once, depending on the pipeline depth of the
    136  *    camera HAL device.
    137  *
    138  * 11. After some time, the framework may stop submitting new requests, wait for
    139  *    the existing captures to complete (all buffers filled, all results
    140  *    returned), and then call configure_streams() again. This resets the camera
    141  *    hardware and pipeline for a new set of input/output streams. Some streams
    142  *    may be reused from the previous configuration; if these streams' buffers
    143  *    had already been registered with the HAL, they will not be registered
    144  *    again. The framework then continues from step 7, if at least one
    145  *    registered output stream remains (otherwise, step 5 is required first).
    146  *
    147  * 12. Alternatively, the framework may call camera3_device_t->common->close()
    148  *    to end the camera session. This may be called at any time when no other
    149  *    calls from the framework are active, although the call may block until all
    150  *    in-flight captures have completed (all results returned, all buffers
    151  *    filled). After the close call returns, no more calls to the
    152  *    camera3_callback_ops_t functions are allowed from the HAL. Once the
    153  *    close() call is underway, the framework may not call any other HAL device
    154  *    functions.
    155  *
    156  * 13. In case of an error or other asynchronous event, the HAL must call
    157  *    camera3_callback_ops_t->notify() with the appropriate error/event
    158  *    message. After returning from a fatal device-wide error notification, the
    159  *    HAL should act as if close() had been called on it. However, the HAL must
    160  *    either cancel or complete all outstanding captures before calling
    161  *    notify(), so that once notify() is called with a fatal error, the
    162  *    framework will not receive further callbacks from the device. Methods
    163  *    besides close() should return -ENODEV or NULL after the notify() method
    164  *    returns from a fatal error message.
    165  */
    166 
    167 /**
    168  * S3. Operational modes:
    169  *
    170  * The camera 3 HAL device can implement one of two possible operational modes;
    171  * limited and full. Full support is expected from new higher-end
    172  * devices. Limited mode has hardware requirements roughly in line with those
    173  * for a camera HAL device v1 implementation, and is expected from older or
    174  * inexpensive devices. Full is a strict superset of limited, and they share the
    175  * same essential operational flow, as documented above.
    176  *
    177  * The HAL must indicate its level of support with the
    178  * android.info.supportedHardwareLevel static metadata entry, with 0 indicating
    179  * limited mode, and 1 indicating full mode support.
    180  *
    181  * Roughly speaking, limited-mode devices do not allow for application control
    182  * of capture settings (3A control only), high-rate capture of high-resolution
    183  * images, raw sensor readout, or support for YUV output streams above maximum
    184  * recording resolution (JPEG only for large images).
    185  *
    186  * ** Details of limited mode behavior:
    187  *
    188  * - Limited-mode devices do not need to implement accurate synchronization
    189  *   between capture request settings and the actual image data
    190  *   captured. Instead, changes to settings may take effect some time in the
    191  *   future, and possibly not for the same output frame for each settings
    192  *   entry. Rapid changes in settings may result in some settings never being
    193  *   used for a capture. However, captures that include high-resolution output
    194  *   buffers ( > 1080p ) have to use the settings as specified (but see below
    195  *   for processing rate).
    196  *
    197  * - Limited-mode devices do not need to support most of the
    198  *   settings/result/static info metadata. Full-mode devices must support all
    199  *   metadata fields listed in TODO. Specifically, only the following settings
    200  *   are expected to be consumed or produced by a limited-mode HAL device:
    201  *
    202  *   android.control.aeAntibandingMode (controls)
    203  *   android.control.aeExposureCompensation (controls)
    204  *   android.control.aeLock (controls)
    205  *   android.control.aeMode (controls)
    206  *       [OFF means ON_FLASH_TORCH - TODO]
    207  *   android.control.aeRegions (controls)
    208  *   android.control.aeTargetFpsRange (controls)
    209  *   android.control.afMode (controls)
    210  *       [OFF means infinity focus]
    211  *   android.control.afRegions (controls)
    212  *   android.control.awbLock (controls)
    213  *   android.control.awbMode (controls)
    214  *       [OFF not supported]
    215  *   android.control.awbRegions (controls)
    216  *   android.control.captureIntent (controls)
    217  *   android.control.effectMode (controls)
    218  *   android.control.mode (controls)
    219  *       [OFF not supported]
    220  *   android.control.sceneMode (controls)
    221  *   android.control.videoStabilizationMode (controls)
    222  *   android.control.aeAvailableAntibandingModes (static)
    223  *   android.control.aeAvailableModes (static)
    224  *   android.control.aeAvailableTargetFpsRanges (static)
    225  *   android.control.aeCompensationRange (static)
    226  *   android.control.aeCompensationStep (static)
    227  *   android.control.afAvailableModes (static)
    228  *   android.control.availableEffects (static)
    229  *   android.control.availableSceneModes (static)
    230  *   android.control.availableVideoStabilizationModes (static)
    231  *   android.control.awbAvailableModes (static)
    232  *   android.control.maxRegions (static)
    233  *   android.control.sceneModeOverrides (static)
    234  *   android.control.aeRegions (dynamic)
    235  *   android.control.aeState (dynamic)
    236  *   android.control.afMode (dynamic)
    237  *   android.control.afRegions (dynamic)
    238  *   android.control.afState (dynamic)
    239  *   android.control.awbMode (dynamic)
    240  *   android.control.awbRegions (dynamic)
    241  *   android.control.awbState (dynamic)
    242  *   android.control.mode (dynamic)
    243  *
    244  *   android.flash.info.available (static)
    245  *
    246  *   android.info.supportedHardwareLevel (static)
    247  *
    248  *   android.jpeg.gpsCoordinates (controls)
    249  *   android.jpeg.gpsProcessingMethod (controls)
    250  *   android.jpeg.gpsTimestamp (controls)
    251  *   android.jpeg.orientation (controls)
    252  *   android.jpeg.quality (controls)
    253  *   android.jpeg.thumbnailQuality (controls)
    254  *   android.jpeg.thumbnailSize (controls)
    255  *   android.jpeg.availableThumbnailSizes (static)
    256  *   android.jpeg.maxSize (static)
    257  *   android.jpeg.gpsCoordinates (dynamic)
    258  *   android.jpeg.gpsProcessingMethod (dynamic)
    259  *   android.jpeg.gpsTimestamp (dynamic)
    260  *   android.jpeg.orientation (dynamic)
    261  *   android.jpeg.quality (dynamic)
    262  *   android.jpeg.size (dynamic)
    263  *   android.jpeg.thumbnailQuality (dynamic)
    264  *   android.jpeg.thumbnailSize (dynamic)
    265  *
    266  *   android.lens.info.minimumFocusDistance (static)
    267  *
    268  *   android.request.id (controls)
    269  *   android.request.id (dynamic)
    270  *
    271  *   android.scaler.cropRegion (controls)
    272  *       [ignores (x,y), assumes center-zoom]
    273  *   android.scaler.availableFormats (static)
    274  *       [RAW not supported]
    275  *   android.scaler.availableJpegMinDurations (static)
    276  *   android.scaler.availableJpegSizes (static)
    277  *   android.scaler.availableMaxDigitalZoom (static)
    278  *   android.scaler.availableProcessedMinDurations (static)
    279  *   android.scaler.availableProcessedSizes (static)
    280  *       [full resolution not supported]
    281  *   android.scaler.maxDigitalZoom (static)
    282  *   android.scaler.cropRegion (dynamic)
    283  *
    284  *   android.sensor.orientation (static)
    285  *   android.sensor.timestamp (dynamic)
    286  *
    287  *   android.statistics.faceDetectMode (controls)
    288  *   android.statistics.info.availableFaceDetectModes (static)
    289  *   android.statistics.faceDetectMode (dynamic)
    290  *   android.statistics.faceIds (dynamic)
    291  *   android.statistics.faceLandmarks (dynamic)
    292  *   android.statistics.faceRectangles (dynamic)
    293  *   android.statistics.faceScores (dynamic)
    294  *
    295  * - Captures in limited mode that include high-resolution (> 1080p) output
    296  *   buffers may block in process_capture_request() until all the output buffers
    297  *   have been filled. A full-mode HAL device must process sequences of
    298  *   high-resolution requests at the rate indicated in the static metadata for
    299  *   that pixel format. The HAL must still call process_capture_result() to
    300  *   provide the output; the framework must simply be prepared for
    301  *   process_capture_request() to block until after process_capture_result() for
    302  *   that request completes for high-resolution captures for limited-mode
    303  *   devices.
    304  *
    305  */
    306 
    307 /**
    308  * S4. 3A modes and state machines:
    309  *
    310  * While the actual 3A algorithms are up to the HAL implementation, a high-level
    311  * state machine description is defined by the HAL interface, to allow the HAL
    312  * device and the framework to communicate about the current state of 3A, and to
    313  * trigger 3A events.
    314  *
    315  * When the device is opened, all the individual 3A states must be
    316  * STATE_INACTIVE. Stream configuration does not reset 3A. For example, locked
    317  * focus must be maintained across the configure() call.
    318  *
    319  * Triggering a 3A action involves simply setting the relevant trigger entry in
    320  * the settings for the next request to indicate start of trigger. For example,
    321  * the trigger for starting an autofocus scan is setting the entry
    322  * ANDROID_CONTROL_AF_TRIGGER to ANDROID_CONTROL_AF_TRIGGER_START for one
    323  * request, and cancelling an autofocus scan is triggered by setting
    324  * ANDROID_CONTROL_AF_TRIGGER to ANDROID_CONTRL_AF_TRIGGER_CANCEL. Otherwise,
    325  * the entry will not exist, or be set to ANDROID_CONTROL_AF_TRIGGER_IDLE. Each
    326  * request with a trigger entry set to a non-IDLE value will be treated as an
    327  * independent triggering event.
    328  *
    329  * At the top level, 3A is controlled by the ANDROID_CONTROL_MODE setting, which
    330  * selects between no 3A (ANDROID_CONTROL_MODE_OFF), normal AUTO mode
    331  * (ANDROID_CONTROL_MODE_AUTO), and using the scene mode setting
    332  * (ANDROID_CONTROL_USE_SCENE_MODE).
    333  *
    334  * - In OFF mode, each of the individual AE/AF/AWB modes are effectively OFF,
    335  *   and none of the capture controls may be overridden by the 3A routines.
    336  *
    337  * - In AUTO mode, Auto-focus, auto-exposure, and auto-whitebalance all run
    338  *   their own independent algorithms, and have their own mode, state, and
    339  *   trigger metadata entries, as listed in the next section.
    340  *
    341  * - In USE_SCENE_MODE, the value of the ANDROID_CONTROL_SCENE_MODE entry must
    342  *   be used to determine the behavior of 3A routines. In SCENE_MODEs other than
    343  *   FACE_PRIORITY, the HAL must override the values of
    344  *   ANDROId_CONTROL_AE/AWB/AF_MODE to be the mode it prefers for the selected
    345  *   SCENE_MODE. For example, the HAL may prefer SCENE_MODE_NIGHT to use
    346  *   CONTINUOUS_FOCUS AF mode. Any user selection of AE/AWB/AF_MODE when scene
    347  *   must be ignored for these scene modes.
    348  *
    349  * - For SCENE_MODE_FACE_PRIORITY, the AE/AWB/AF_MODE controls work as in
    350  *   ANDROID_CONTROL_MODE_AUTO, but the 3A routines must bias toward metering
    351  *   and focusing on any detected faces in the scene.
    352  *
    353  * S4.1. Auto-focus settings and result entries:
    354  *
    355  *  Main metadata entries:
    356  *
    357  *   ANDROID_CONTROL_AF_MODE: Control for selecting the current autofocus
    358  *      mode. Set by the framework in the request settings.
    359  *
    360  *     AF_MODE_OFF: AF is disabled; the framework/app directly controls lens
    361  *         position.
    362  *
    363  *     AF_MODE_AUTO: Single-sweep autofocus. No lens movement unless AF is
    364  *         triggered.
    365  *
    366  *     AF_MODE_MACRO: Single-sweep up-close autofocus. No lens movement unless
    367  *         AF is triggered.
    368  *
    369  *     AF_MODE_CONTINUOUS_VIDEO: Smooth continuous focusing, for recording
    370  *         video. Triggering immediately locks focus in current
    371  *         position. Canceling resumes cotinuous focusing.
    372  *
    373  *     AF_MODE_CONTINUOUS_PICTURE: Fast continuous focusing, for
    374  *        zero-shutter-lag still capture. Triggering locks focus once currently
    375  *        active sweep concludes. Canceling resumes continuous focusing.
    376  *
    377  *     AF_MODE_EDOF: Advanced extended depth of field focusing. There is no
    378  *        autofocus scan, so triggering one or canceling one has no effect.
    379  *        Images are focused automatically by the HAL.
    380  *
    381  *   ANDROID_CONTROL_AF_STATE: Dynamic metadata describing the current AF
    382  *       algorithm state, reported by the HAL in the result metadata.
    383  *
    384  *     AF_STATE_INACTIVE: No focusing has been done, or algorithm was
    385  *        reset. Lens is not moving. Always the state for MODE_OFF or MODE_EDOF.
    386  *        When the device is opened, it must start in this state.
    387  *
    388  *     AF_STATE_PASSIVE_SCAN: A continuous focus algorithm is currently scanning
    389  *        for good focus. The lens is moving.
    390  *
    391  *     AF_STATE_PASSIVE_FOCUSED: A continuous focus algorithm believes it is
    392  *        well focused. The lens is not moving. The HAL may spontaneously leave
    393  *        this state.
    394  *
    395  *     AF_STATE_ACTIVE_SCAN: A scan triggered by the user is underway.
    396  *
    397  *     AF_STATE_FOCUSED_LOCKED: The AF algorithm believes it is focused. The
    398  *        lens is not moving.
    399  *
    400  *     AF_STATE_NOT_FOCUSED_LOCKED: The AF algorithm has been unable to
    401  *        focus. The lens is not moving.
    402  *
    403  *   ANDROID_CONTROL_AF_TRIGGER: Control for starting an autofocus scan, the
    404  *       meaning of which is mode- and state- dependent. Set by the framework in
    405  *       the request settings.
    406  *
    407  *     AF_TRIGGER_IDLE: No current trigger.
    408  *
    409  *     AF_TRIGGER_START: Trigger start of AF scan. Effect is mode and state
    410  *         dependent.
    411  *
    412  *     AF_TRIGGER_CANCEL: Cancel current AF scan if any, and reset algorithm to
    413  *         default.
    414  *
    415  *  Additional metadata entries:
    416  *
    417  *   ANDROID_CONTROL_AF_REGIONS: Control for selecting the regions of the FOV
    418  *       that should be used to determine good focus. This applies to all AF
    419  *       modes that scan for focus. Set by the framework in the request
    420  *       settings.
    421  *
    422  * S4.2. Auto-exposure settings and result entries:
    423  *
    424  *  Main metadata entries:
    425  *
    426  *   ANDROID_CONTROL_AE_MODE: Control for selecting the current auto-exposure
    427  *       mode. Set by the framework in the request settings.
    428  *
    429  *     AE_MODE_OFF: Autoexposure is disabled; the user controls exposure, gain,
    430  *         frame duration, and flash.
    431  *
    432  *     AE_MODE_ON: Standard autoexposure, with flash control disabled. User may
    433  *         set flash to fire or to torch mode.
    434  *
    435  *     AE_MODE_ON_AUTO_FLASH: Standard autoexposure, with flash on at HAL's
    436  *         discretion for precapture and still capture. User control of flash
    437  *         disabled.
    438  *
    439  *     AE_MODE_ON_ALWAYS_FLASH: Standard autoexposure, with flash always fired
    440  *         for capture, and at HAL's discretion for precapture.. User control of
    441  *         flash disabled.
    442  *
    443  *     AE_MODE_ON_AUTO_FLASH_REDEYE: Standard autoexposure, with flash on at
    444  *         HAL's discretion for precapture and still capture. Use a flash burst
    445  *         at end of precapture sequence to reduce redeye in the final
    446  *         picture. User control of flash disabled.
    447  *
    448  *   ANDROID_CONTROL_AE_STATE: Dynamic metadata describing the current AE
    449  *       algorithm state, reported by the HAL in the result metadata.
    450  *
    451  *     AE_STATE_INACTIVE: Initial AE state after mode switch. When the device is
    452  *         opened, it must start in this state.
    453  *
    454  *     AE_STATE_SEARCHING: AE is not converged to a good value, and is adjusting
    455  *         exposure parameters.
    456  *
    457  *     AE_STATE_CONVERGED: AE has found good exposure values for the current
    458  *         scene, and the exposure parameters are not changing. HAL may
    459  *         spontaneously leave this state to search for better solution.
    460  *
    461  *     AE_STATE_LOCKED: AE has been locked with the AE_LOCK control. Exposure
    462  *         values are not changing.
    463  *
    464  *     AE_STATE_FLASH_REQUIRED: The HAL has converged exposure, but believes
    465  *         flash is required for a sufficiently bright picture. Used for
    466  *         determining if a zero-shutter-lag frame can be used.
    467  *
    468  *     AE_STATE_PRECAPTURE: The HAL is in the middle of a precapture
    469  *         sequence. Depending on AE mode, this mode may involve firing the
    470  *         flash for metering, or a burst of flash pulses for redeye reduction.
    471  *
    472  *   ANDROID_CONTROL_AE_PRECAPTURE_TRIGGER: Control for starting a metering
    473  *       sequence before capturing a high-quality image. Set by the framework in
    474  *       the request settings.
    475  *
    476  *      PRECAPTURE_TRIGGER_IDLE: No current trigger.
    477  *
    478  *      PRECAPTURE_TRIGGER_START: Start a precapture sequence. The HAL should
    479  *         use the subsequent requests to measure good exposure/white balance
    480  *         for an upcoming high-resolution capture.
    481  *
    482  *  Additional metadata entries:
    483  *
    484  *   ANDROID_CONTROL_AE_LOCK: Control for locking AE controls to their current
    485  *       values
    486  *
    487  *   ANDROID_CONTROL_AE_EXPOSURE_COMPENSATION: Control for adjusting AE
    488  *       algorithm target brightness point.
    489  *
    490  *   ANDROID_CONTROL_AE_TARGET_FPS_RANGE: Control for selecting the target frame
    491  *       rate range for the AE algorithm. The AE routine cannot change the frame
    492  *       rate to be outside these bounds.
    493  *
    494  *   ANDROID_CONTROL_AE_REGIONS: Control for selecting the regions of the FOV
    495  *       that should be used to determine good exposure levels. This applies to
    496  *       all AE modes besides OFF.
    497  *
    498  * S4.3. Auto-whitebalance settings and result entries:
    499  *
    500  *  Main metadata entries:
    501  *
    502  *   ANDROID_CONTROL_AWB_MODE: Control for selecting the current white-balance
    503  *       mode.
    504  *
    505  *     AWB_MODE_OFF: Auto-whitebalance is disabled. User controls color matrix.
    506  *
    507  *     AWB_MODE_AUTO: Automatic white balance is enabled; 3A controls color
    508  *        transform, possibly using more complex transforms than a simple
    509  *        matrix.
    510  *
    511  *     AWB_MODE_INCANDESCENT: Fixed white balance settings good for indoor
    512  *        incandescent (tungsten) lighting, roughly 2700K.
    513  *
    514  *     AWB_MODE_FLUORESCENT: Fixed white balance settings good for fluorescent
    515  *        lighting, roughly 5000K.
    516  *
    517  *     AWB_MODE_WARM_FLUORESCENT: Fixed white balance settings good for
    518  *        fluorescent lighting, roughly 3000K.
    519  *
    520  *     AWB_MODE_DAYLIGHT: Fixed white balance settings good for daylight,
    521  *        roughly 5500K.
    522  *
    523  *     AWB_MODE_CLOUDY_DAYLIGHT: Fixed white balance settings good for clouded
    524  *        daylight, roughly 6500K.
    525  *
    526  *     AWB_MODE_TWILIGHT: Fixed white balance settings good for
    527  *        near-sunset/sunrise, roughly 15000K.
    528  *
    529  *     AWB_MODE_SHADE: Fixed white balance settings good for areas indirectly
    530  *        lit by the sun, roughly 7500K.
    531  *
    532  *   ANDROID_CONTROL_AWB_STATE: Dynamic metadata describing the current AWB
    533  *       algorithm state, reported by the HAL in the result metadata.
    534  *
    535  *     AWB_STATE_INACTIVE: Initial AWB state after mode switch. When the device
    536  *         is opened, it must start in this state.
    537  *
    538  *     AWB_STATE_SEARCHING: AWB is not converged to a good value, and is
    539  *         changing color adjustment parameters.
    540  *
    541  *     AWB_STATE_CONVERGED: AWB has found good color adjustment values for the
    542  *         current scene, and the parameters are not changing. HAL may
    543  *         spontaneously leave this state to search for better solution.
    544  *
    545  *     AWB_STATE_LOCKED: AWB has been locked with the AWB_LOCK control. Color
    546  *         adjustment values are not changing.
    547  *
    548  *  Additional metadata entries:
    549  *
    550  *   ANDROID_CONTROL_AWB_LOCK: Control for locking AWB color adjustments to
    551  *       their current values.
    552  *
    553  *   ANDROID_CONTROL_AWB_REGIONS: Control for selecting the regions of the FOV
    554  *       that should be used to determine good color balance. This applies only
    555  *       to auto-WB mode.
    556  *
    557  * S4.4. General state machine transition notes
    558  *
    559  *   Switching between AF, AE, or AWB modes always resets the algorithm's state
    560  *   to INACTIVE.  Similarly, switching between CONTROL_MODE or
    561  *   CONTROL_SCENE_MODE if CONTROL_MODE == USE_SCENE_MODE resets all the
    562  *   algorithm states to INACTIVE.
    563  *
    564  *   The tables below are per-mode.
    565  *
    566  * S4.5. AF state machines
    567  *
    568  *                            mode = AF_MODE_OFF or AF_MODE_EDOF
    569  *| state              | trans. cause  | new state          | notes            |
    570  *+--------------------+---------------+--------------------+------------------+
    571  *| INACTIVE           |               |                    | AF is disabled   |
    572  *+--------------------+---------------+--------------------+------------------+
    573  *
    574  *                            mode = AF_MODE_AUTO or AF_MODE_MACRO
    575  *| state              | trans. cause  | new state          | notes            |
    576  *+--------------------+---------------+--------------------+------------------+
    577  *| INACTIVE           | AF_TRIGGER    | ACTIVE_SCAN        | Start AF sweep   |
    578  *|                    |               |                    | Lens now moving  |
    579  *+--------------------+---------------+--------------------+------------------+
    580  *| ACTIVE_SCAN        | AF sweep done | FOCUSED_LOCKED     | If AF successful |
    581  *|                    |               |                    | Lens now locked  |
    582  *+--------------------+---------------+--------------------+------------------+
    583  *| ACTIVE_SCAN        | AF sweep done | NOT_FOCUSED_LOCKED | If AF successful |
    584  *|                    |               |                    | Lens now locked  |
    585  *+--------------------+---------------+--------------------+------------------+
    586  *| ACTIVE_SCAN        | AF_CANCEL     | INACTIVE           | Cancel/reset AF  |
    587  *|                    |               |                    | Lens now locked  |
    588  *+--------------------+---------------+--------------------+------------------+
    589  *| FOCUSED_LOCKED     | AF_CANCEL     | INACTIVE           | Cancel/reset AF  |
    590  *+--------------------+---------------+--------------------+------------------+
    591  *| FOCUSED_LOCKED     | AF_TRIGGER    | ACTIVE_SCAN        | Start new sweep  |
    592  *|                    |               |                    | Lens now moving  |
    593  *+--------------------+---------------+--------------------+------------------+
    594  *| NOT_FOCUSED_LOCKED | AF_CANCEL     | INACTIVE           | Cancel/reset AF  |
    595  *+--------------------+---------------+--------------------+------------------+
    596  *| NOT_FOCUSED_LOCKED | AF_TRIGGER    | ACTIVE_SCAN        | Start new sweep  |
    597  *|                    |               |                    | Lens now moving  |
    598  *+--------------------+---------------+--------------------+------------------+
    599  *| All states         | mode change   | INACTIVE           |                  |
    600  *+--------------------+---------------+--------------------+------------------+
    601  *
    602  *                            mode = AF_MODE_CONTINUOUS_VIDEO
    603  *| state              | trans. cause  | new state          | notes            |
    604  *+--------------------+---------------+--------------------+------------------+
    605  *| INACTIVE           | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
    606  *|                    | new scan      |                    | Lens now moving  |
    607  *+--------------------+---------------+--------------------+------------------+
    608  *| INACTIVE           | AF_TRIGGER    | NOT_FOCUSED_LOCKED | AF state query   |
    609  *|                    |               |                    | Lens now locked  |
    610  *+--------------------+---------------+--------------------+------------------+
    611  *| PASSIVE_SCAN       | HAL completes | PASSIVE_FOCUSED    | End AF scan      |
    612  *|                    | current scan  |                    | Lens now locked  |
    613  *+--------------------+---------------+--------------------+------------------+
    614  *| PASSIVE_SCAN       | AF_TRIGGER    | FOCUSED_LOCKED     | Immediate trans. |
    615  *|                    |               |                    | if focus is good |
    616  *|                    |               |                    | Lens now locked  |
    617  *+--------------------+---------------+--------------------+------------------+
    618  *| PASSIVE_SCAN       | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Immediate trans. |
    619  *|                    |               |                    | if focus is bad  |
    620  *|                    |               |                    | Lens now locked  |
    621  *+--------------------+---------------+--------------------+------------------+
    622  *| PASSIVE_SCAN       | AF_CANCEL     | INACTIVE           | Reset lens       |
    623  *|                    |               |                    | position         |
    624  *|                    |               |                    | Lens now locked  |
    625  *+--------------------+---------------+--------------------+------------------+
    626  *| PASSIVE_FOCUSED    | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
    627  *|                    | new scan      |                    | Lens now moving  |
    628  *+--------------------+---------------+--------------------+------------------+
    629  *| PASSIVE_FOCUSED    | AF_TRIGGER    | FOCUSED_LOCKED     | Immediate trans. |
    630  *|                    |               |                    | if focus is good |
    631  *|                    |               |                    | Lens now locked  |
    632  *+--------------------+---------------+--------------------+------------------+
    633  *| PASSIVE_FOCUSED    | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Immediate trans. |
    634  *|                    |               |                    | if focus is bad  |
    635  *|                    |               |                    | Lens now locked  |
    636  *+--------------------+---------------+--------------------+------------------+
    637  *| FOCUSED_LOCKED     | AF_TRIGGER    | FOCUSED_LOCKED     | No effect        |
    638  *+--------------------+---------------+--------------------+------------------+
    639  *| FOCUSED_LOCKED     | AF_CANCEL     | INACTIVE           | Restart AF scan  |
    640  *+--------------------+---------------+--------------------+------------------+
    641  *| NOT_FOCUSED_LOCKED | AF_TRIGGER    | NOT_FOCUSED_LOCKED | No effect        |
    642  *+--------------------+---------------+--------------------+------------------+
    643  *| NOT_FOCUSED_LOCKED | AF_CANCEL     | INACTIVE           | Restart AF scan  |
    644  *+--------------------+---------------+--------------------+------------------+
    645  *
    646  *                            mode = AF_MODE_CONTINUOUS_PICTURE
    647  *| state              | trans. cause  | new state          | notes            |
    648  *+--------------------+---------------+--------------------+------------------+
    649  *| INACTIVE           | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
    650  *|                    | new scan      |                    | Lens now moving  |
    651  *+--------------------+---------------+--------------------+------------------+
    652  *| INACTIVE           | AF_TRIGGER    | NOT_FOCUSED_LOCKED | AF state query   |
    653  *|                    |               |                    | Lens now locked  |
    654  *+--------------------+---------------+--------------------+------------------+
    655  *| PASSIVE_SCAN       | HAL completes | PASSIVE_FOCUSED    | End AF scan      |
    656  *|                    | current scan  |                    | Lens now locked  |
    657  *+--------------------+---------------+--------------------+------------------+
    658  *| PASSIVE_SCAN       | AF_TRIGGER    | FOCUSED_LOCKED     | Eventual trans.  |
    659  *|                    |               |                    | once focus good  |
    660  *|                    |               |                    | Lens now locked  |
    661  *+--------------------+---------------+--------------------+------------------+
    662  *| PASSIVE_SCAN       | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Eventual trans.  |
    663  *|                    |               |                    | if cannot focus  |
    664  *|                    |               |                    | Lens now locked  |
    665  *+--------------------+---------------+--------------------+------------------+
    666  *| PASSIVE_SCAN       | AF_CANCEL     | INACTIVE           | Reset lens       |
    667  *|                    |               |                    | position         |
    668  *|                    |               |                    | Lens now locked  |
    669  *+--------------------+---------------+--------------------+------------------+
    670  *| PASSIVE_FOCUSED    | HAL initiates | PASSIVE_SCAN       | Start AF scan    |
    671  *|                    | new scan      |                    | Lens now moving  |
    672  *+--------------------+---------------+--------------------+------------------+
    673  *| PASSIVE_FOCUSED    | AF_TRIGGER    | FOCUSED_LOCKED     | Immediate trans. |
    674  *|                    |               |                    | if focus is good |
    675  *|                    |               |                    | Lens now locked  |
    676  *+--------------------+---------------+--------------------+------------------+
    677  *| PASSIVE_FOCUSED    | AF_TRIGGER    | NOT_FOCUSED_LOCKED | Immediate trans. |
    678  *|                    |               |                    | if focus is bad  |
    679  *|                    |               |                    | Lens now locked  |
    680  *+--------------------+---------------+--------------------+------------------+
    681  *| FOCUSED_LOCKED     | AF_TRIGGER    | FOCUSED_LOCKED     | No effect        |
    682  *+--------------------+---------------+--------------------+------------------+
    683  *| FOCUSED_LOCKED     | AF_CANCEL     | INACTIVE           | Restart AF scan  |
    684  *+--------------------+---------------+--------------------+------------------+
    685  *| NOT_FOCUSED_LOCKED | AF_TRIGGER    | NOT_FOCUSED_LOCKED | No effect        |
    686  *+--------------------+---------------+--------------------+------------------+
    687  *| NOT_FOCUSED_LOCKED | AF_CANCEL     | INACTIVE           | Restart AF scan  |
    688  *+--------------------+---------------+--------------------+------------------+
    689  *
    690  * S4.6. AE and AWB state machines
    691  *
    692  *   The AE and AWB state machines are mostly identical. AE has additional
    693  *   FLASH_REQUIRED and PRECAPTURE states. So rows below that refer to those two
    694  *   states should be ignored for the AWB state machine.
    695  *
    696  *                            mode = AE_MODE_OFF / AWB mode not AUTO
    697  *| state              | trans. cause  | new state          | notes            |
    698  *+--------------------+---------------+--------------------+------------------+
    699  *| INACTIVE           |               |                    | AE/AWB disabled  |
    700  *+--------------------+---------------+--------------------+------------------+
    701  *
    702  *                            mode = AE_MODE_ON_* / AWB_MODE_AUTO
    703  *| state              | trans. cause  | new state          | notes            |
    704  *+--------------------+---------------+--------------------+------------------+
    705  *| INACTIVE           | HAL initiates | SEARCHING          |                  |
    706  *|                    | AE/AWB scan   |                    |                  |
    707  *+--------------------+---------------+--------------------+------------------+
    708  *| INACTIVE           | AE/AWB_LOCK   | LOCKED             | values locked    |
    709  *|                    | on            |                    |                  |
    710  *+--------------------+---------------+--------------------+------------------+
    711  *| SEARCHING          | HAL finishes  | CONVERGED          | good values, not |
    712  *|                    | AE/AWB scan   |                    | changing         |
    713  *+--------------------+---------------+--------------------+------------------+
    714  *| SEARCHING          | HAL finishes  | FLASH_REQUIRED     | converged but too|
    715  *|                    | AE scan       |                    | dark w/o flash   |
    716  *+--------------------+---------------+--------------------+------------------+
    717  *| SEARCHING          | AE/AWB_LOCK   | LOCKED             | values locked    |
    718  *|                    | on            |                    |                  |
    719  *+--------------------+---------------+--------------------+------------------+
    720  *| CONVERGED          | HAL initiates | SEARCHING          | values locked    |
    721  *|                    | AE/AWB scan   |                    |                  |
    722  *+--------------------+---------------+--------------------+------------------+
    723  *| CONVERGED          | AE/AWB_LOCK   | LOCKED             | values locked    |
    724  *|                    | on            |                    |                  |
    725  *+--------------------+---------------+--------------------+------------------+
    726  *| FLASH_REQUIRED     | HAL initiates | SEARCHING          | values locked    |
    727  *|                    | AE/AWB scan   |                    |                  |
    728  *+--------------------+---------------+--------------------+------------------+
    729  *| FLASH_REQUIRED     | AE/AWB_LOCK   | LOCKED             | values locked    |
    730  *|                    | on            |                    |                  |
    731  *+--------------------+---------------+--------------------+------------------+
    732  *| LOCKED             | AE/AWB_LOCK   | SEARCHING          | values not good  |
    733  *|                    | off           |                    | after unlock     |
    734  *+--------------------+---------------+--------------------+------------------+
    735  *| LOCKED             | AE/AWB_LOCK   | CONVERGED          | values good      |
    736  *|                    | off           |                    | after unlock     |
    737  *+--------------------+---------------+--------------------+------------------+
    738  *| LOCKED             | AE_LOCK       | FLASH_REQUIRED     | exposure good,   |
    739  *|                    | off           |                    | but too dark     |
    740  *+--------------------+---------------+--------------------+------------------+
    741  *| All AE states      | PRECAPTURE_   | PRECAPTURE         | Start precapture |
    742  *|                    | START         |                    | sequence         |
    743  *+--------------------+---------------+--------------------+------------------+
    744  *| PRECAPTURE         | Sequence done.| CONVERGED          | Ready for high-  |
    745  *|                    | AE_LOCK off   |                    | quality capture  |
    746  *+--------------------+---------------+--------------------+------------------+
    747  *| PRECAPTURE         | Sequence done.| LOCKED             | Ready for high-  |
    748  *|                    | AE_LOCK on    |                    | quality capture  |
    749  *+--------------------+---------------+--------------------+------------------+
    750  *
    751  */
    752 
    753 /**
    754  * S5. Cropping:
    755  *
    756  * Cropping of the full pixel array (for digital zoom and other use cases where
    757  * a smaller FOV is desirable) is communicated through the
    758  * ANDROID_SCALER_CROP_REGION setting. This is a per-request setting, and can
    759  * change on a per-request basis, which is critical for implementing smooth
    760  * digital zoom.
    761  *
    762  * The region is defined as a rectangle (x, y, width, height), with (x, y)
    763  * describing the top-left corner of the rectangle. The rectangle is defined on
    764  * the coordinate system of the sensor active pixel array, with (0,0) being the
    765  * top-left pixel of the active pixel array. Therefore, the width and height
    766  * cannot be larger than the dimensions reported in the
    767  * ANDROID_SENSOR_ACTIVE_PIXEL_ARRAY static info field. The minimum allowed
    768  * width and height are reported by the HAL through the
    769  * ANDROID_SCALER_MAX_DIGITAL_ZOOM static info field, which describes the
    770  * maximum supported zoom factor. Therefore, the minimum crop region width and
    771  * height are:
    772  *
    773  * {width, height} =
    774  *    { floor(ANDROID_SENSOR_ACTIVE_PIXEL_ARRAY[0] /
    775  *        ANDROID_SCALER_MAX_DIGITAL_ZOOM),
    776  *      floor(ANDROID_SENSOR_ACTIVE_PIXEL_ARRAY[1] /
    777  *        ANDROID_SCALER_MAX_DIGITAL_ZOOM) }
    778  *
    779  * If the crop region needs to fulfill specific requirements (for example, it
    780  * needs to start on even coordinates, and its width/height needs to be even),
    781  * the HAL must do the necessary rounding and write out the final crop region
    782  * used in the output result metadata. Similarly, if the HAL implements video
    783  * stabilization, it must adjust the result crop region to describe the region
    784  * actually included in the output after video stabilization is applied. In
    785  * general, a camera-using application must be able to determine the field of
    786  * view it is receiving based on the crop region, the dimensions of the image
    787  * sensor, and the lens focal length.
    788  *
    789  * Since the crop region applies to all streams, which may have different aspect
    790  * ratios than the crop region, the exact sensor region used for each stream may
    791  * be smaller than the crop region. Specifically, each stream should maintain
    792  * square pixels and its aspect ratio by minimally further cropping the defined
    793  * crop region. If the stream's aspect ratio is wider than the crop region, the
    794  * stream should be further cropped vertically, and if the stream's aspect ratio
    795  * is narrower than the crop region, the stream should be further cropped
    796  * horizontally.
    797  *
    798  * In all cases, the stream crop must be centered within the full crop region,
    799  * and each stream is only either cropped horizontally or vertical relative to
    800  * the full crop region, never both.
    801  *
    802  * For example, if two streams are defined, a 640x480 stream (4:3 aspect), and a
    803  * 1280x720 stream (16:9 aspect), below demonstrates the expected output regions
    804  * for each stream for a few sample crop regions, on a hypothetical 3 MP (2000 x
    805  * 1500 pixel array) sensor.
    806  *
    807  * Crop region: (500, 375, 1000, 750) (4:3 aspect ratio)
    808  *
    809  *   640x480 stream crop: (500, 375, 1000, 750) (equal to crop region)
    810  *   1280x720 stream crop: (500, 469, 1000, 562) (marked with =)
    811  *
    812  * 0                   1000               2000
    813  * +---------+---------+---------+----------+
    814  * | Active pixel array                     |
    815  * |                                        |
    816  * |                                        |
    817  * +         +-------------------+          + 375
    818  * |         |                   |          |
    819  * |         O===================O          |
    820  * |         I 1280x720 stream   I          |
    821  * +         I                   I          + 750
    822  * |         I                   I          |
    823  * |         O===================O          |
    824  * |         |                   |          |
    825  * +         +-------------------+          + 1125
    826  * |          Crop region, 640x480 stream   |
    827  * |                                        |
    828  * |                                        |
    829  * +---------+---------+---------+----------+ 1500
    830  *
    831  * Crop region: (500, 375, 1333, 750) (16:9 aspect ratio)
    832  *
    833  *   640x480 stream crop: (666, 375, 1000, 750) (marked with =)
    834  *   1280x720 stream crop: (500, 375, 1333, 750) (equal to crop region)
    835  *
    836  * 0                   1000               2000
    837  * +---------+---------+---------+----------+
    838  * | Active pixel array                     |
    839  * |                                        |
    840  * |                                        |
    841  * +         +---O==================O---+   + 375
    842  * |         |   I 640x480 stream   I   |   |
    843  * |         |   I                  I   |   |
    844  * |         |   I                  I   |   |
    845  * +         |   I                  I   |   + 750
    846  * |         |   I                  I   |   |
    847  * |         |   I                  I   |   |
    848  * |         |   I                  I   |   |
    849  * +         +---O==================O---+   + 1125
    850  * |          Crop region, 1280x720 stream  |
    851  * |                                        |
    852  * |                                        |
    853  * +---------+---------+---------+----------+ 1500
    854  *
    855  * Crop region: (500, 375, 750, 750) (1:1 aspect ratio)
    856  *
    857  *   640x480 stream crop: (500, 469, 750, 562) (marked with =)
    858  *   1280x720 stream crop: (500, 543, 750, 414) (marged with #)
    859  *
    860  * 0                   1000               2000
    861  * +---------+---------+---------+----------+
    862  * | Active pixel array                     |
    863  * |                                        |
    864  * |                                        |
    865  * +         +--------------+               + 375
    866  * |         O==============O               |
    867  * |         ################               |
    868  * |         #              #               |
    869  * +         #              #               + 750
    870  * |         #              #               |
    871  * |         ################ 1280x720      |
    872  * |         O==============O 640x480       |
    873  * +         +--------------+               + 1125
    874  * |          Crop region                   |
    875  * |                                        |
    876  * |                                        |
    877  * +---------+---------+---------+----------+ 1500
    878  *
    879  * And a final example, a 1024x1024 square aspect ratio stream instead of the
    880  * 480p stream:
    881  *
    882  * Crop region: (500, 375, 1000, 750) (4:3 aspect ratio)
    883  *
    884  *   1024x1024 stream crop: (625, 375, 750, 750) (marked with #)
    885  *   1280x720 stream crop: (500, 469, 1000, 562) (marked with =)
    886  *
    887  * 0                   1000               2000
    888  * +---------+---------+---------+----------+
    889  * | Active pixel array                     |
    890  * |                                        |
    891  * |              1024x1024 stream          |
    892  * +         +--###############--+          + 375
    893  * |         |  #             #  |          |
    894  * |         O===================O          |
    895  * |         I 1280x720 stream   I          |
    896  * +         I                   I          + 750
    897  * |         I                   I          |
    898  * |         O===================O          |
    899  * |         |  #             #  |          |
    900  * +         +--###############--+          + 1125
    901  * |          Crop region                   |
    902  * |                                        |
    903  * |                                        |
    904  * +---------+---------+---------+----------+ 1500
    905  *
    906  */
    907 
    908 /**
    909  * S6. Error management:
    910  *
    911  * Camera HAL device ops functions that have a return value will all return
    912  * -ENODEV / NULL in case of a serious error. This means the device cannot
    913  * continue operation, and must be closed by the framework. Once this error is
    914  * returned by some method, or if notify() is called with ERROR_DEVICE, only
    915  * the close() method can be called successfully. All other methods will return
    916  * -ENODEV / NULL.
    917  *
    918  * If a device op is called in the wrong sequence, for example if the framework
    919  * calls configure_streams() is called before initialize(), the device must
    920  * return -ENOSYS from the call, and do nothing.
    921  *
    922  * Transient errors in image capture must be reported through notify() as follows:
    923  *
    924  * - The failure of an entire capture to occur must be reported by the HAL by
    925  *   calling notify() with ERROR_REQUEST. Individual errors for the result
    926  *   metadata or the output buffers must not be reported in this case.
    927  *
    928  * - If the metadata for a capture cannot be produced, but some image buffers
    929  *   were filled, the HAL must call notify() with ERROR_RESULT.
    930  *
    931  * - If an output image buffer could not be filled, but either the metadata was
    932  *   produced or some other buffers were filled, the HAL must call notify() with
    933  *   ERROR_BUFFER for each failed buffer.
    934  *
    935  * In each of these transient failure cases, the HAL must still call
    936  * process_capture_result, with valid output buffer_handle_t. If the result
    937  * metadata could not be produced, it should be NULL. If some buffers could not
    938  * be filled, their sync fences must be set to the error state.
    939  *
    940  * Invalid input arguments result in -EINVAL from the appropriate methods. In
    941  * that case, the framework must act as if that call had never been made.
    942  *
    943  */
    944 
    945 __BEGIN_DECLS
    946 
    947 struct camera3_device;
    948 
    949 /**********************************************************************
    950  *
    951  * Camera3 stream and stream buffer definitions.
    952  *
    953  * These structs and enums define the handles and contents of the input and
    954  * output streams connecting the HAL to various framework and application buffer
    955  * consumers. Each stream is backed by a gralloc buffer queue.
    956  *
    957  */
    958 
    959 /**
    960  * camera3_stream_type_t:
    961  *
    962  * The type of the camera stream, which defines whether the camera HAL device is
    963  * the producer or the consumer for that stream, and how the buffers of the
    964  * stream relate to the other streams.
    965  */
    966 typedef enum camera3_stream_type {
    967     /**
    968      * This stream is an output stream; the camera HAL device will be
    969      * responsible for filling buffers from this stream with newly captured or
    970      * reprocessed image data.
    971      */
    972     CAMERA3_STREAM_OUTPUT = 0,
    973 
    974     /**
    975      * This stream is an input stream; the camera HAL device will be responsible
    976      * for reading buffers from this stream and sending them through the camera
    977      * processing pipeline, as if the buffer was a newly captured image from the
    978      * imager.
    979      */
    980     CAMERA3_STREAM_INPUT = 1,
    981 
    982     /**
    983      * This stream can be used for input and output. Typically, the stream is
    984      * used as an output stream, but occasionally one already-filled buffer may
    985      * be sent back to the HAL device for reprocessing.
    986      *
    987      * This kind of stream is meant generally for zero-shutter-lag features,
    988      * where copying the captured image from the output buffer to the
    989      * reprocessing input buffer would be expensive. The stream will be used by
    990      * the framework as follows:
    991      *
    992      * 1. The framework includes a buffer from this stream as output buffer in a
    993      *    request as normal.
    994      *
    995      * 2. Once the HAL device returns a filled output buffer to the framework,
    996      *    the framework may do one of two things with the filled buffer:
    997      *
    998      * 2. a. The framework uses the filled data, and returns the now-used buffer
    999      *       to the stream queue for reuse. This behavior exactly matches the
   1000      *       OUTPUT type of stream.
   1001      *
   1002      * 2. b. The framework wants to reprocess the filled data, and uses the
   1003      *       buffer as an input buffer for a request. Once the HAL device has
   1004      *       used the reprocessing buffer, it then returns it to the
   1005      *       framework. The framework then returns the now-used buffer to the
   1006      *       stream queue for reuse.
   1007      *
   1008      * 3. The HAL device will be given the buffer again as an output buffer for
   1009      *    a request at some future point.
   1010      *
   1011      * Note that the HAL will always be reprocessing data it produced.
   1012      *
   1013      */
   1014     CAMERA3_STREAM_BIDIRECTIONAL = 2,
   1015 
   1016     /**
   1017      * Total number of framework-defined stream types
   1018      */
   1019     CAMERA3_NUM_STREAM_TYPES
   1020 
   1021 } camera3_stream_type_t;
   1022 
   1023 /**
   1024  * camera3_stream_t:
   1025  *
   1026  * A handle to a single camera input or output stream. A stream is defined by
   1027  * the framework by its buffer resolution and format, and additionally by the
   1028  * HAL with the gralloc usage flags and the maximum in-flight buffer count.
   1029  *
   1030  * The stream structures are owned by the framework, but pointers to a
   1031  * camera3_stream passed into the HAL by configure_streams() are valid until the
   1032  * end of the first subsequent configure_streams() call that _does not_ include
   1033  * that camera3_stream as an argument, or until the end of the close() call.
   1034  *
   1035  * All camera3_stream framework-controlled members are immutable once the
   1036  * camera3_stream is passed into configure_streams().  The HAL may only change
   1037  * the HAL-controlled parameters during a configure_streams() call, except for
   1038  * the contents of the private pointer.
   1039  *
   1040  * If a configure_streams() call returns a non-fatal error, all active streams
   1041  * remain valid as if configure_streams() had not been called.
   1042  *
   1043  * The endpoint of the stream is not visible to the camera HAL device.
   1044  */
   1045 typedef struct camera3_stream {
   1046 
   1047     /*****
   1048      * Set by framework before configure_streams()
   1049      */
   1050 
   1051     /**
   1052      * The type of the stream, one of the camera3_stream_type_t values.
   1053      */
   1054     int stream_type;
   1055 
   1056     /**
   1057      * The width in pixels of the buffers in this stream
   1058      */
   1059     uint32_t width;
   1060 
   1061     /**
   1062      * The height in pixels of the buffers in this stream
   1063      */
   1064     uint32_t height;
   1065 
   1066     /**
   1067      * The pixel format for the buffers in this stream. Format is a value from
   1068      * the HAL_PIXEL_FORMAT_* list in system/core/include/system/graphics.h, or
   1069      * from device-specific headers.
   1070      *
   1071      * If HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED is used, then the platform
   1072      * gralloc module will select a format based on the usage flags provided by
   1073      * the camera device and the other endpoint of the stream.
   1074      *
   1075      * The camera HAL device must inspect the buffers handed to it in the
   1076      * subsequent register_stream_buffers() call to obtain the
   1077      * implementation-specific format details, if necessary.
   1078      */
   1079     int format;
   1080 
   1081     /*****
   1082      * Set by HAL during configure_streams().
   1083      */
   1084 
   1085     /**
   1086      * The gralloc usage flags for this stream, as needed by the HAL. The usage
   1087      * flags are defined in gralloc.h (GRALLOC_USAGE_*), or in device-specific
   1088      * headers.
   1089      *
   1090      * For output streams, these are the HAL's producer usage flags. For input
   1091      * streams, these are the HAL's consumer usage flags. The usage flags from
   1092      * the producer and the consumer will be combined together and then passed
   1093      * to the platform gralloc HAL module for allocating the gralloc buffers for
   1094      * each stream.
   1095      */
   1096     uint32_t usage;
   1097 
   1098     /**
   1099      * The maximum number of buffers the HAL device may need to have dequeued at
   1100      * the same time. The HAL device may not have more buffers in-flight from
   1101      * this stream than this value.
   1102      */
   1103     uint32_t max_buffers;
   1104 
   1105     /**
   1106      * A handle to HAL-private information for the stream. Will not be inspected
   1107      * by the framework code.
   1108      */
   1109     void *priv;
   1110 
   1111 } camera3_stream_t;
   1112 
   1113 /**
   1114  * camera3_stream_configuration_t:
   1115  *
   1116  * A structure of stream definitions, used by configure_streams(). This
   1117  * structure defines all the output streams and the reprocessing input
   1118  * stream for the current camera use case.
   1119  */
   1120 typedef struct camera3_stream_configuration {
   1121     /**
   1122      * The total number of streams requested by the framework.  This includes
   1123      * both input and output streams. The number of streams will be at least 1,
   1124      * and there will be at least one output-capable stream.
   1125      */
   1126     uint32_t num_streams;
   1127 
   1128     /**
   1129      * An array of camera stream pointers, defining the input/output
   1130      * configuration for the camera HAL device.
   1131      *
   1132      * At most one input-capable stream may be defined (INPUT or BIDIRECTIONAL)
   1133      * in a single configuration.
   1134      *
   1135      * At least one output-capable stream must be defined (OUTPUT or
   1136      * BIDIRECTIONAL).
   1137      */
   1138     camera3_stream_t **streams;
   1139 
   1140 } camera3_stream_configuration_t;
   1141 
   1142 /**
   1143  * camera3_buffer_status_t:
   1144  *
   1145  * The current status of a single stream buffer.
   1146  */
   1147 typedef enum camera3_buffer_status {
   1148     /**
   1149      * The buffer is in a normal state, and can be used after waiting on its
   1150      * sync fence.
   1151      */
   1152     CAMERA3_BUFFER_STATUS_OK = 0,
   1153 
   1154     /**
   1155      * The buffer does not contain valid data, and the data in it should not be
   1156      * used. The sync fence must still be waited on before reusing the buffer.
   1157      */
   1158     CAMERA3_BUFFER_STATUS_ERROR = 1
   1159 
   1160 } camera3_buffer_status_t;
   1161 
   1162 /**
   1163  * camera3_stream_buffer_t:
   1164  *
   1165  * A single buffer from a camera3 stream. It includes a handle to its parent
   1166  * stream, the handle to the gralloc buffer itself, and sync fences
   1167  *
   1168  * The buffer does not specify whether it is to be used for input or output;
   1169  * that is determined by its parent stream type and how the buffer is passed to
   1170  * the HAL device.
   1171  */
   1172 typedef struct camera3_stream_buffer {
   1173     /**
   1174      * The handle of the stream this buffer is associated with
   1175      */
   1176     camera3_stream_t *stream;
   1177 
   1178     /**
   1179      * The native handle to the buffer
   1180      */
   1181     buffer_handle_t *buffer;
   1182 
   1183     /**
   1184      * Current state of the buffer, one of the camera3_buffer_status_t
   1185      * values. The framework will not pass buffers to the HAL that are in an
   1186      * error state. In case a buffer could not be filled by the HAL, it must
   1187      * have its status set to CAMERA3_BUFFER_STATUS_ERROR when returned to the
   1188      * framework with process_capture_result().
   1189      */
   1190     int status;
   1191 
   1192     /**
   1193      * The acquire sync fence for this buffer. The HAL must wait on this fence
   1194      * fd before attempting to read from or write to this buffer.
   1195      *
   1196      * The framework may be set to -1 to indicate that no waiting is necessary
   1197      * for this buffer.
   1198      *
   1199      * When the HAL returns an output buffer to the framework with
   1200      * process_capture_result(), the acquire_fence must be set to -1. If the HAL
   1201      * never waits on the acquire_fence due to an error in filling a buffer,
   1202      * when calling process_capture_result() the HAL must set the release_fence
   1203      * of the buffer to be the acquire_fence passed to it by the framework. This
   1204      * will allow the framework to wait on the fence before reusing the buffer.
   1205      *
   1206      * For input buffers, the HAL must not change the acquire_fence field during
   1207      * the process_capture_request() call.
   1208      */
   1209      int acquire_fence;
   1210 
   1211     /**
   1212      * The release sync fence for this buffer. The HAL must set this fence when
   1213      * returning buffers to the framework, or write -1 to indicate that no
   1214      * waiting is required for this buffer.
   1215      *
   1216      * For the input buffer, the release fence must be set by the
   1217      * process_capture_request() call. For the output buffers, the fences must
   1218      * be set in the output_buffers array passed to process_capture_result().
   1219      *
   1220      */
   1221     int release_fence;
   1222 
   1223 } camera3_stream_buffer_t;
   1224 
   1225 /**
   1226  * camera3_stream_buffer_set_t:
   1227  *
   1228  * The complete set of gralloc buffers for a stream. This structure is given to
   1229  * register_stream_buffers() to allow the camera HAL device to register/map/etc
   1230  * newly allocated stream buffers.
   1231  */
   1232 typedef struct camera3_stream_buffer_set {
   1233     /**
   1234      * The stream handle for the stream these buffers belong to
   1235      */
   1236     camera3_stream_t *stream;
   1237 
   1238     /**
   1239      * The number of buffers in this stream. It is guaranteed to be at least
   1240      * stream->max_buffers.
   1241      */
   1242     uint32_t num_buffers;
   1243 
   1244     /**
   1245      * The array of gralloc buffer handles for this stream. If the stream format
   1246      * is set to HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, the camera HAL device
   1247      * should inspect the passed-in buffers to determine any platform-private
   1248      * pixel format information.
   1249      */
   1250     buffer_handle_t **buffers;
   1251 
   1252 } camera3_stream_buffer_set_t;
   1253 
   1254 /**
   1255  * camera3_jpeg_blob:
   1256  *
   1257  * Transport header for compressed JPEG buffers in output streams.
   1258  *
   1259  * To capture JPEG images, a stream is created using the pixel format
   1260  * HAL_PIXEL_FORMAT_BLOB, and the static metadata field android.jpeg.maxSize is
   1261  * used as the buffer size. Since compressed JPEG images are of variable size,
   1262  * the HAL needs to include the final size of the compressed image using this
   1263  * structure inside the output stream buffer. The JPEG blob ID field must be set
   1264  * to CAMERA3_JPEG_BLOB_ID.
   1265  *
   1266  * Transport header should be at the end of the JPEG output stream buffer.  That
   1267  * means the jpeg_blob_id must start at byte[android.jpeg.maxSize -
   1268  * sizeof(camera3_jpeg_blob)].  Any HAL using this transport header must
   1269  * account for it in android.jpeg.maxSize.  The JPEG data itself starts at
   1270  * the beginning of the buffer and should be jpeg_size bytes long.
   1271  */
   1272 typedef struct camera3_jpeg_blob {
   1273     uint16_t jpeg_blob_id;
   1274     uint32_t jpeg_size;
   1275 } camera3_jpeg_blob_t;
   1276 
   1277 enum {
   1278     CAMERA3_JPEG_BLOB_ID = 0x00FF
   1279 };
   1280 
   1281 /**********************************************************************
   1282  *
   1283  * Message definitions for the HAL notify() callback.
   1284  *
   1285  * These definitions are used for the HAL notify callback, to signal
   1286  * asynchronous events from the HAL device to the Android framework.
   1287  *
   1288  */
   1289 
   1290 /**
   1291  * camera3_msg_type:
   1292  *
   1293  * Indicates the type of message sent, which specifies which member of the
   1294  * message union is valid.
   1295  *
   1296  */
   1297 typedef enum camera3_msg_type {
   1298     /**
   1299      * An error has occurred. camera3_notify_msg.message.error contains the
   1300      * error information.
   1301      */
   1302     CAMERA3_MSG_ERROR = 1,
   1303 
   1304     /**
   1305      * The exposure of a given request has
   1306      * begun. camera3_notify_msg.message.shutter contains the information
   1307      * the capture.
   1308      */
   1309     CAMERA3_MSG_SHUTTER = 2,
   1310 
   1311     /**
   1312      * Number of framework message types
   1313      */
   1314     CAMERA3_NUM_MESSAGES
   1315 
   1316 } camera3_msg_type_t;
   1317 
   1318 /**
   1319  * Defined error codes for CAMERA_MSG_ERROR
   1320  */
   1321 typedef enum camera3_error_msg_code {
   1322     /**
   1323      * A serious failure occured. No further frames or buffer streams will
   1324      * be produced by the device. Device should be treated as closed. The
   1325      * client must reopen the device to use it again. The frame_number field
   1326      * is unused.
   1327      */
   1328     CAMERA3_MSG_ERROR_DEVICE = 1,
   1329 
   1330     /**
   1331      * An error has occurred in processing a request. No output (metadata or
   1332      * buffers) will be produced for this request. The frame_number field
   1333      * specifies which request has been dropped. Subsequent requests are
   1334      * unaffected, and the device remains operational.
   1335      */
   1336     CAMERA3_MSG_ERROR_REQUEST = 2,
   1337 
   1338     /**
   1339      * An error has occurred in producing an output result metadata buffer
   1340      * for a request, but output stream buffers for it will still be
   1341      * available. Subsequent requests are unaffected, and the device remains
   1342      * operational.  The frame_number field specifies the request for which
   1343      * result metadata won't be available.
   1344      */
   1345     CAMERA3_MSG_ERROR_RESULT = 3,
   1346 
   1347     /**
   1348      * An error has occurred in placing an output buffer into a stream for a
   1349      * request. The frame metadata and other buffers may still be
   1350      * available. Subsequent requests are unaffected, and the device remains
   1351      * operational. The frame_number field specifies the request for which the
   1352      * buffer was dropped, and error_stream contains a pointer to the stream
   1353      * that dropped the frame.u
   1354      */
   1355     CAMERA3_MSG_ERROR_BUFFER = 4,
   1356 
   1357     /**
   1358      * Number of error types
   1359      */
   1360     CAMERA3_MSG_NUM_ERRORS
   1361 
   1362 } camera3_error_msg_code_t;
   1363 
   1364 /**
   1365  * camera3_error_msg_t:
   1366  *
   1367  * Message contents for CAMERA3_MSG_ERROR
   1368  */
   1369 typedef struct camera3_error_msg {
   1370     /**
   1371      * Frame number of the request the error applies to. 0 if the frame number
   1372      * isn't applicable to the error.
   1373      */
   1374     uint32_t frame_number;
   1375 
   1376     /**
   1377      * Pointer to the stream that had a failure. NULL if the stream isn't
   1378      * applicable to the error.
   1379      */
   1380     camera3_stream_t *error_stream;
   1381 
   1382     /**
   1383      * The code for this error; one of the CAMERA_MSG_ERROR enum values.
   1384      */
   1385     int error_code;
   1386 
   1387 } camera3_error_msg_t;
   1388 
   1389 /**
   1390  * camera3_shutter_msg_t:
   1391  *
   1392  * Message contents for CAMERA3_MSG_SHUTTER
   1393  */
   1394 typedef struct camera3_shutter_msg {
   1395     /**
   1396      * Frame number of the request that has begun exposure
   1397      */
   1398     uint32_t frame_number;
   1399 
   1400     /**
   1401      * Timestamp for the start of capture. This must match the capture result
   1402      * metadata's sensor exposure start timestamp.
   1403      */
   1404     uint64_t timestamp;
   1405 
   1406 } camera3_shutter_msg_t;
   1407 
   1408 /**
   1409  * camera3_notify_msg_t:
   1410  *
   1411  * The message structure sent to camera3_callback_ops_t.notify()
   1412  */
   1413 typedef struct camera3_notify_msg {
   1414 
   1415     /**
   1416      * The message type. One of camera3_notify_msg_type, or a private extension.
   1417      */
   1418     int type;
   1419 
   1420     union {
   1421         /**
   1422          * Error message contents. Valid if type is CAMERA3_MSG_ERROR
   1423          */
   1424         camera3_error_msg_t error;
   1425 
   1426         /**
   1427          * Shutter message contents. Valid if type is CAMERA3_MSG_SHUTTER
   1428          */
   1429         camera3_shutter_msg_t shutter;
   1430 
   1431         /**
   1432          * Generic message contents. Used to ensure a minimum size for custom
   1433          * message types.
   1434          */
   1435         uint8_t generic[32];
   1436     } message;
   1437 
   1438 } camera3_notify_msg_t;
   1439 
   1440 /**********************************************************************
   1441  *
   1442  * Capture request/result definitions for the HAL process_capture_request()
   1443  * method, and the process_capture_result() callback.
   1444  *
   1445  */
   1446 
   1447 /**
   1448  * camera3_request_template_t:
   1449  *
   1450  * Available template types for
   1451  * camera3_device_ops.construct_default_request_settings()
   1452  */
   1453 typedef enum camera3_request_template {
   1454     /**
   1455      * Standard camera preview operation with 3A on auto.
   1456      */
   1457     CAMERA3_TEMPLATE_PREVIEW = 1,
   1458 
   1459     /**
   1460      * Standard camera high-quality still capture with 3A and flash on auto.
   1461      */
   1462     CAMERA3_TEMPLATE_STILL_CAPTURE = 2,
   1463 
   1464     /**
   1465      * Standard video recording plus preview with 3A on auto, torch off.
   1466      */
   1467     CAMERA3_TEMPLATE_VIDEO_RECORD = 3,
   1468 
   1469     /**
   1470      * High-quality still capture while recording video. Application will
   1471      * include preview, video record, and full-resolution YUV or JPEG streams in
   1472      * request. Must not cause stuttering on video stream. 3A on auto.
   1473      */
   1474     CAMERA3_TEMPLATE_VIDEO_SNAPSHOT = 4,
   1475 
   1476     /**
   1477      * Zero-shutter-lag mode. Application will request preview and
   1478      * full-resolution data for each frame, and reprocess it to JPEG when a
   1479      * still image is requested by user. Settings should provide highest-quality
   1480      * full-resolution images without compromising preview frame rate. 3A on
   1481      * auto.
   1482      */
   1483     CAMERA3_TEMPLATE_ZERO_SHUTTER_LAG = 5,
   1484 
   1485     /* Total number of templates */
   1486     CAMERA3_TEMPLATE_COUNT,
   1487 
   1488     /**
   1489      * First value for vendor-defined request templates
   1490      */
   1491     CAMERA3_VENDOR_TEMPLATE_START = 0x40000000
   1492 
   1493 } camera3_request_template_t;
   1494 
   1495 /**
   1496  * camera3_capture_request_t:
   1497  *
   1498  * A single request for image capture/buffer reprocessing, sent to the Camera
   1499  * HAL device by the framework in process_capture_request().
   1500  *
   1501  * The request contains the settings to be used for this capture, and the set of
   1502  * output buffers to write the resulting image data in. It may optionally
   1503  * contain an input buffer, in which case the request is for reprocessing that
   1504  * input buffer instead of capturing a new image with the camera sensor. The
   1505  * capture is identified by the frame_number.
   1506  *
   1507  * In response, the camera HAL device must send a camera3_capture_result
   1508  * structure asynchronously to the framework, using the process_capture_result()
   1509  * callback.
   1510  */
   1511 typedef struct camera3_capture_request {
   1512     /**
   1513      * The frame number is an incrementing integer set by the framework to
   1514      * uniquely identify this capture. It needs to be returned in the result
   1515      * call, and is also used to identify the request in asynchronous
   1516      * notifications sent to camera3_callback_ops_t.notify().
   1517      */
   1518     uint32_t frame_number;
   1519 
   1520     /**
   1521      * The settings buffer contains the capture and processing parameters for
   1522      * the request. As a special case, a NULL settings buffer indicates that the
   1523      * settings are identical to the most-recently submitted capture request. A
   1524      * NULL buffer cannot be used as the first submitted request after a
   1525      * configure_streams() call.
   1526      */
   1527     const camera_metadata_t *settings;
   1528 
   1529     /**
   1530      * The input stream buffer to use for this request, if any.
   1531      *
   1532      * If input_buffer is NULL, then the request is for a new capture from the
   1533      * imager. If input_buffer is valid, the request is for reprocessing the
   1534      * image contained in input_buffer.
   1535      *
   1536      * In the latter case, the HAL must set the release_fence of the
   1537      * input_buffer to a valid sync fence, or to -1 if the HAL does not support
   1538      * sync, before process_capture_request() returns.
   1539      *
   1540      * The HAL is required to wait on the acquire sync fence of the input buffer
   1541      * before accessing it.
   1542      *
   1543      * Any input buffer included here will have been registered with the HAL
   1544      * through register_stream_buffers() before its inclusion in a request.
   1545      */
   1546     camera3_stream_buffer_t *input_buffer;
   1547 
   1548     /**
   1549      * The number of output buffers for this capture request. Must be at least
   1550      * 1.
   1551      */
   1552     uint32_t num_output_buffers;
   1553 
   1554     /**
   1555      * An array of num_output_buffers stream buffers, to be filled with image
   1556      * data from this capture/reprocess. The HAL must wait on the acquire fences
   1557      * of each stream buffer before writing to them. All the buffers included
   1558      * here will have been registered with the HAL through
   1559      * register_stream_buffers() before their inclusion in a request.
   1560      *
   1561      * The HAL takes ownership of the actual buffer_handle_t entries in
   1562      * output_buffers; the framework does not access them until they are
   1563      * returned in a camera3_capture_result_t.
   1564      */
   1565     const camera3_stream_buffer_t *output_buffers;
   1566 
   1567 } camera3_capture_request_t;
   1568 
   1569 /**
   1570  * camera3_capture_result_t:
   1571  *
   1572  * The result of a single capture/reprocess by the camera HAL device. This is
   1573  * sent to the framework asynchronously with process_capture_result(), in
   1574  * response to a single capture request sent to the HAL with
   1575  * process_capture_request(). Multiple process_capture_result() calls may be
   1576  * performed by the HAL for each request. Each call, all with the same frame
   1577  * number, may contain some subset of the output buffers, and/or the result
   1578  * metadata. The metadata may only be provided once for a given frame number;
   1579  * all other calls must set the result metadata to NULL.
   1580  *
   1581  * The result structure contains the output metadata from this capture, and the
   1582  * set of output buffers that have been/will be filled for this capture. Each
   1583  * output buffer may come with a release sync fence that the framework will wait
   1584  * on before reading, in case the buffer has not yet been filled by the HAL.
   1585  *
   1586  */
   1587 typedef struct camera3_capture_result {
   1588     /**
   1589      * The frame number is an incrementing integer set by the framework in the
   1590      * submitted request to uniquely identify this capture. It is also used to
   1591      * identify the request in asynchronous notifications sent to
   1592      * camera3_callback_ops_t.notify().
   1593     */
   1594     uint32_t frame_number;
   1595 
   1596     /**
   1597      * The result metadata for this capture. This contains information about the
   1598      * final capture parameters, the state of the capture and post-processing
   1599      * hardware, the state of the 3A algorithms, if enabled, and the output of
   1600      * any enabled statistics units.
   1601      *
   1602      * Only one call to process_capture_result() with a given frame_number may
   1603      * include the result metadata. All other calls for the same frame_number
   1604      * must set this to NULL.
   1605      *
   1606      * If there was an error producing the result metadata, result must be an
   1607      * empty metadata buffer, and notify() must be called with ERROR_RESULT.
   1608      */
   1609     const camera_metadata_t *result;
   1610 
   1611     /**
   1612      * The number of output buffers returned in this result structure. Must be
   1613      * less than or equal to the matching capture request's count. If this is
   1614      * less than the buffer count in the capture request, at least one more call
   1615      * to process_capture_result with the same frame_number must be made, to
   1616      * return the remaining output buffers to the framework. This may only be
   1617      * zero if the structure includes valid result metadata.
   1618      */
   1619     uint32_t num_output_buffers;
   1620 
   1621     /**
   1622      * The handles for the output stream buffers for this capture. They may not
   1623      * yet be filled at the time the HAL calls process_capture_result(); the
   1624      * framework will wait on the release sync fences provided by the HAL before
   1625      * reading the buffers.
   1626      *
   1627      * The HAL must set the stream buffer's release sync fence to a valid sync
   1628      * fd, or to -1 if the buffer has already been filled.
   1629      *
   1630      * If the HAL encounters an error while processing the buffer, and the
   1631      * buffer is not filled, the buffer's status field must be set to
   1632      * CAMERA3_BUFFER_STATUS_ERROR. If the HAL did not wait on the acquire fence
   1633      * before encountering the error, the acquire fence should be copied into
   1634      * the release fence, to allow the framework to wait on the fence before
   1635      * reusing the buffer.
   1636      *
   1637      * The acquire fence must be set to -1 for all output buffers.  If
   1638      * num_output_buffers is zero, this may be NULL. In that case, at least one
   1639      * more process_capture_result call must be made by the HAL to provide the
   1640      * output buffers.
   1641      */
   1642      const camera3_stream_buffer_t *output_buffers;
   1643 
   1644 } camera3_capture_result_t;
   1645 
   1646 /**********************************************************************
   1647  *
   1648  * Callback methods for the HAL to call into the framework.
   1649  *
   1650  * These methods are used to return metadata and image buffers for a completed
   1651  * or failed captures, and to notify the framework of asynchronous events such
   1652  * as errors.
   1653  *
   1654  * The framework will not call back into the HAL from within these callbacks,
   1655  * and these calls will not block for extended periods.
   1656  *
   1657  */
   1658 typedef struct camera3_callback_ops {
   1659 
   1660     /**
   1661      * process_capture_result:
   1662      *
   1663      * Send results from a completed capture to the framework.
   1664      * process_capture_result() may be invoked multiple times by the HAL in
   1665      * response to a single capture request. This allows, for example, the
   1666      * metadata and low-resolution buffers to be returned in one call, and
   1667      * post-processed JPEG buffers in a later call, once it is available. Each
   1668      * call must include the frame number of the request it is returning
   1669      * metadata or buffers for.
   1670      *
   1671      * A component (buffer or metadata) of the complete result may only be
   1672      * included in one process_capture_result call. A buffer for each stream,
   1673      * and the result metadata, must be returned by the HAL for each request in
   1674      * one of the process_capture_result calls, even in case of errors producing
   1675      * some of the output. A call to process_capture_result() with neither
   1676      * output buffers or result metadata is not allowed.
   1677      *
   1678      * The order of returning metadata and buffers for a single result does not
   1679      * matter, but buffers for a given stream must be returned in FIFO order. So
   1680      * the buffer for request 5 for stream A must always be returned before the
   1681      * buffer for request 6 for stream A. This also applies to the result
   1682      * metadata; the metadata for request 5 must be returned before the metadata
   1683      * for request 6.
   1684      *
   1685      * However, different streams are independent of each other, so it is
   1686      * acceptable and expected that the buffer for request 5 for stream A may be
   1687      * returned after the buffer for request 6 for stream B is. And it is
   1688      * acceptable that the result metadata for request 6 for stream B is
   1689      * returned before the buffer for request 5 for stream A is.
   1690      *
   1691      * The HAL retains ownership of result structure, which only needs to be
   1692      * valid to access during this call. The framework will copy whatever it
   1693      * needs before this call returns.
   1694      *
   1695      * The output buffers do not need to be filled yet; the framework will wait
   1696      * on the stream buffer release sync fence before reading the buffer
   1697      * data. Therefore, this method should be called by the HAL as soon as
   1698      * possible, even if some or all of the output buffers are still in
   1699      * being filled. The HAL must include valid release sync fences into each
   1700      * output_buffers stream buffer entry, or -1 if that stream buffer is
   1701      * already filled.
   1702      *
   1703      * If the result buffer cannot be constructed for a request, the HAL should
   1704      * return an empty metadata buffer, but still provide the output buffers and
   1705      * their sync fences. In addition, notify() must be called with an
   1706      * ERROR_RESULT message.
   1707      *
   1708      * If an output buffer cannot be filled, its status field must be set to
   1709      * STATUS_ERROR. In addition, notify() must be called with a ERROR_BUFFER
   1710      * message.
   1711      *
   1712      * If the entire capture has failed, then this method still needs to be
   1713      * called to return the output buffers to the framework. All the buffer
   1714      * statuses should be STATUS_ERROR, and the result metadata should be an
   1715      * empty buffer. In addition, notify() must be called with a ERROR_REQUEST
   1716      * message. In this case, individual ERROR_RESULT/ERROR_BUFFER messages
   1717      * should not be sent.
   1718      *
   1719      */
   1720     void (*process_capture_result)(const struct camera3_callback_ops *,
   1721             const camera3_capture_result_t *result);
   1722 
   1723     /**
   1724      * notify:
   1725      *
   1726      * Asynchronous notification callback from the HAL, fired for various
   1727      * reasons. Only for information independent of frame capture, or that
   1728      * require specific timing. The ownership of the message structure remains
   1729      * with the HAL, and the msg only needs to be valid for the duration of this
   1730      * call.
   1731      *
   1732      * The notification for the start of exposure for a given request must be
   1733      * sent by the HAL before the first call to process_capture_result() for
   1734      * that request is made.
   1735      *
   1736      * Multiple threads may call notify() simultaneously.
   1737      */
   1738     void (*notify)(const struct camera3_callback_ops *,
   1739             const camera3_notify_msg_t *msg);
   1740 
   1741 } camera3_callback_ops_t;
   1742 
   1743 /**********************************************************************
   1744  *
   1745  * Camera device operations
   1746  *
   1747  */
   1748 typedef struct camera3_device_ops {
   1749 
   1750     /**
   1751      * initialize:
   1752      *
   1753      * One-time initialization to pass framework callback function pointers to
   1754      * the HAL. Will be called once after a successful open() call, before any
   1755      * other functions are called on the camera3_device_ops structure.
   1756      *
   1757      * Return values:
   1758      *
   1759      *  0:     On successful initialization
   1760      *
   1761      * -ENODEV: If initialization fails. Only close() can be called successfully
   1762      *          by the framework after this.
   1763      */
   1764     int (*initialize)(const struct camera3_device *,
   1765             const camera3_callback_ops_t *callback_ops);
   1766 
   1767     /**********************************************************************
   1768      * Stream management
   1769      */
   1770 
   1771     /**
   1772      * configure_streams:
   1773      *
   1774      * Reset the HAL camera device processing pipeline and set up new input and
   1775      * output streams. This call replaces any existing stream configuration with
   1776      * the streams defined in the stream_list. This method will be called at
   1777      * least once after initialize() before a request is submitted with
   1778      * process_capture_request().
   1779      *
   1780      * The stream_list must contain at least one output-capable stream, and may
   1781      * not contain more than one input-capable stream.
   1782      *
   1783      * The stream_list may contain streams that are also in the currently-active
   1784      * set of streams (from the previous call to configure_stream()). These
   1785      * streams will already have valid values for usage, max_buffers, and the
   1786      * private pointer. If such a stream has already had its buffers registered,
   1787      * register_stream_buffers() will not be called again for the stream, and
   1788      * buffers from the stream can be immediately included in input requests.
   1789      *
   1790      * If the HAL needs to change the stream configuration for an existing
   1791      * stream due to the new configuration, it may rewrite the values of usage
   1792      * and/or max_buffers during the configure call. The framework will detect
   1793      * such a change, and will then reallocate the stream buffers, and call
   1794      * register_stream_buffers() again before using buffers from that stream in
   1795      * a request.
   1796      *
   1797      * If a currently-active stream is not included in stream_list, the HAL may
   1798      * safely remove any references to that stream. It will not be reused in a
   1799      * later configure() call by the framework, and all the gralloc buffers for
   1800      * it will be freed after the configure_streams() call returns.
   1801      *
   1802      * The stream_list structure is owned by the framework, and may not be
   1803      * accessed once this call completes. The address of an individual
   1804      * camera3_stream_t structure will remain valid for access by the HAL until
   1805      * the end of the first configure_stream() call which no longer includes
   1806      * that camera3_stream_t in the stream_list argument. The HAL may not change
   1807      * values in the stream structure outside of the private pointer, except for
   1808      * the usage and max_buffers members during the configure_streams() call
   1809      * itself.
   1810      *
   1811      * If the stream is new, the usage, max_buffer, and private pointer fields
   1812      * of the stream structure will all be set to 0. The HAL device must set
   1813      * these fields before the configure_streams() call returns. These fields
   1814      * are then used by the framework and the platform gralloc module to
   1815      * allocate the gralloc buffers for each stream.
   1816      *
   1817      * Before such a new stream can have its buffers included in a capture
   1818      * request, the framework will call register_stream_buffers() with that
   1819      * stream. However, the framework is not required to register buffers for
   1820      * _all_ streams before submitting a request. This allows for quick startup
   1821      * of (for example) a preview stream, with allocation for other streams
   1822      * happening later or concurrently.
   1823      *
   1824      * Preconditions:
   1825      *
   1826      * The framework will only call this method when no captures are being
   1827      * processed. That is, all results have been returned to the framework, and
   1828      * all in-flight input and output buffers have been returned and their
   1829      * release sync fences have been signaled by the HAL. The framework will not
   1830      * submit new requests for capture while the configure_streams() call is
   1831      * underway.
   1832      *
   1833      * Postconditions:
   1834      *
   1835      * The HAL device must configure itself to provide maximum possible output
   1836      * frame rate given the sizes and formats of the output streams, as
   1837      * documented in the camera device's static metadata.
   1838      *
   1839      * Performance expectations:
   1840      *
   1841      * This call is expected to be heavyweight and possibly take several hundred
   1842      * milliseconds to complete, since it may require resetting and
   1843      * reconfiguring the image sensor and the camera processing pipeline.
   1844      * Nevertheless, the HAL device should attempt to minimize the
   1845      * reconfiguration delay to minimize the user-visible pauses during
   1846      * application operational mode changes (such as switching from still
   1847      * capture to video recording).
   1848      *
   1849      * Return values:
   1850      *
   1851      *  0:      On successful stream configuration
   1852      *
   1853      * -EINVAL: If the requested stream configuration is invalid. Some examples
   1854      *          of invalid stream configurations include:
   1855      *
   1856      *          - Including more than 1 input-capable stream (INPUT or
   1857      *            BIDIRECTIONAL)
   1858      *
   1859      *          - Not including any output-capable streams (OUTPUT or
   1860      *            BIDIRECTIONAL)
   1861      *
   1862      *          - Including streams with unsupported formats, or an unsupported
   1863      *            size for that format.
   1864      *
   1865      *          - Including too many output streams of a certain format.
   1866      *
   1867      *          Note that the framework submitting an invalid stream
   1868      *          configuration is not normal operation, since stream
   1869      *          configurations are checked before configure. An invalid
   1870      *          configuration means that a bug exists in the framework code, or
   1871      *          there is a mismatch between the HAL's static metadata and the
   1872      *          requirements on streams.
   1873      *
   1874      * -ENODEV: If there has been a fatal error and the device is no longer
   1875      *          operational. Only close() can be called successfully by the
   1876      *          framework after this error is returned.
   1877      */
   1878     int (*configure_streams)(const struct camera3_device *,
   1879             camera3_stream_configuration_t *stream_list);
   1880 
   1881     /**
   1882      * register_stream_buffers:
   1883      *
   1884      * Register buffers for a given stream with the HAL device. This method is
   1885      * called by the framework after a new stream is defined by
   1886      * configure_streams, and before buffers from that stream are included in a
   1887      * capture request. If the same stream is listed in a subsequent
   1888      * configure_streams() call, register_stream_buffers will _not_ be called
   1889      * again for that stream.
   1890      *
   1891      * The framework does not need to register buffers for all configured
   1892      * streams before it submits the first capture request. This allows quick
   1893      * startup for preview (or similar use cases) while other streams are still
   1894      * being allocated.
   1895      *
   1896      * This method is intended to allow the HAL device to map or otherwise
   1897      * prepare the buffers for later use. The buffers passed in will already be
   1898      * locked for use. At the end of the call, all the buffers must be ready to
   1899      * be returned to the stream.  The buffer_set argument is only valid for the
   1900      * duration of this call.
   1901      *
   1902      * If the stream format was set to HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED,
   1903      * the camera HAL should inspect the passed-in buffers here to determine any
   1904      * platform-private pixel format information.
   1905      *
   1906      * Return values:
   1907      *
   1908      *  0:      On successful registration of the new stream buffers
   1909      *
   1910      * -EINVAL: If the stream_buffer_set does not refer to a valid active
   1911      *          stream, or if the buffers array is invalid.
   1912      *
   1913      * -ENOMEM: If there was a failure in registering the buffers. The framework
   1914      *          must consider all the stream buffers to be unregistered, and can
   1915      *          try to register again later.
   1916      *
   1917      * -ENODEV: If there is a fatal error, and the device is no longer
   1918      *          operational. Only close() can be called successfully by the
   1919      *          framework after this error is returned.
   1920      */
   1921     int (*register_stream_buffers)(const struct camera3_device *,
   1922             const camera3_stream_buffer_set_t *buffer_set);
   1923 
   1924     /**********************************************************************
   1925      * Request creation and submission
   1926      */
   1927 
   1928     /**
   1929      * construct_default_request_settings:
   1930      *
   1931      * Create capture settings for standard camera use cases.
   1932      *
   1933      * The device must return a settings buffer that is configured to meet the
   1934      * requested use case, which must be one of the CAMERA3_TEMPLATE_*
   1935      * enums. All request control fields must be included.
   1936      *
   1937      * The HAL retains ownership of this structure, but the pointer to the
   1938      * structure must be valid until the device is closed. The framework and the
   1939      * HAL may not modify the buffer once it is returned by this call. The same
   1940      * buffer may be returned for subsequent calls for the same template, or for
   1941      * other templates.
   1942      *
   1943      * Return values:
   1944      *
   1945      *   Valid metadata: On successful creation of a default settings
   1946      *                   buffer.
   1947      *
   1948      *   NULL:           In case of a fatal error. After this is returned, only
   1949      *                   the close() method can be called successfully by the
   1950      *                   framework.
   1951      */
   1952     const camera_metadata_t* (*construct_default_request_settings)(
   1953             const struct camera3_device *,
   1954             int type);
   1955 
   1956     /**
   1957      * process_capture_request:
   1958      *
   1959      * Send a new capture request to the HAL. The HAL should not return from
   1960      * this call until it is ready to accept the next request to process. Only
   1961      * one call to process_capture_request() will be made at a time by the
   1962      * framework, and the calls will all be from the same thread. The next call
   1963      * to process_capture_request() will be made as soon as a new request and
   1964      * its associated buffers are available. In a normal preview scenario, this
   1965      * means the function will be called again by the framework almost
   1966      * instantly.
   1967      *
   1968      * The actual request processing is asynchronous, with the results of
   1969      * capture being returned by the HAL through the process_capture_result()
   1970      * call. This call requires the result metadata to be available, but output
   1971      * buffers may simply provide sync fences to wait on. Multiple requests are
   1972      * expected to be in flight at once, to maintain full output frame rate.
   1973      *
   1974      * The framework retains ownership of the request structure. It is only
   1975      * guaranteed to be valid during this call. The HAL device must make copies
   1976      * of the information it needs to retain for the capture processing. The HAL
   1977      * is responsible for waiting on and closing the buffers' fences and
   1978      * returning the buffer handles to the framework.
   1979      *
   1980      * The HAL must write the file descriptor for the input buffer's release
   1981      * sync fence into input_buffer->release_fence, if input_buffer is not
   1982      * NULL. If the HAL returns -1 for the input buffer release sync fence, the
   1983      * framework is free to immediately reuse the input buffer. Otherwise, the
   1984      * framework will wait on the sync fence before refilling and reusing the
   1985      * input buffer.
   1986      *
   1987      * Return values:
   1988      *
   1989      *  0:      On a successful start to processing the capture request
   1990      *
   1991      * -EINVAL: If the input is malformed (the settings are NULL when not
   1992      *          allowed, there are 0 output buffers, etc) and capture processing
   1993      *          cannot start. Failures during request processing should be
   1994      *          handled by calling camera3_callback_ops_t.notify(). In case of
   1995      *          this error, the framework will retain responsibility for the
   1996      *          stream buffers' fences and the buffer handles; the HAL should
   1997      *          not close the fences or return these buffers with
   1998      *          process_capture_result.
   1999      *
   2000      * -ENODEV: If the camera device has encountered a serious error. After this
   2001      *          error is returned, only the close() method can be successfully
   2002      *          called by the framework.
   2003      *
   2004      */
   2005     int (*process_capture_request)(const struct camera3_device *,
   2006             camera3_capture_request_t *request);
   2007 
   2008     /**********************************************************************
   2009      * Miscellaneous methods
   2010      */
   2011 
   2012     /**
   2013      * get_metadata_vendor_tag_ops:
   2014      *
   2015      * Get methods to query for vendor extension metadata tag information. The
   2016      * HAL should fill in all the vendor tag operation methods, or leave ops
   2017      * unchanged if no vendor tags are defined.
   2018      *
   2019      * The definition of vendor_tag_query_ops_t can be found in
   2020      * system/media/camera/include/system/camera_metadata.h.
   2021      *
   2022      */
   2023     void (*get_metadata_vendor_tag_ops)(const struct camera3_device*,
   2024             vendor_tag_query_ops_t* ops);
   2025 
   2026     /**
   2027      * dump:
   2028      *
   2029      * Print out debugging state for the camera device. This will be called by
   2030      * the framework when the camera service is asked for a debug dump, which
   2031      * happens when using the dumpsys tool, or when capturing a bugreport.
   2032      *
   2033      * The passed-in file descriptor can be used to write debugging text using
   2034      * dprintf() or write(). The text should be in ASCII encoding only.
   2035      */
   2036     void (*dump)(const struct camera3_device *, int fd);
   2037 
   2038 } camera3_device_ops_t;
   2039 
   2040 /**********************************************************************
   2041  *
   2042  * Camera device definition
   2043  *
   2044  */
   2045 typedef struct camera3_device {
   2046     /**
   2047      * common.version must equal CAMERA_DEVICE_API_VERSION_3_0 to identify this
   2048      * device as implementing version 3.0 of the camera device HAL.
   2049      */
   2050     hw_device_t common;
   2051     camera3_device_ops_t *ops;
   2052     void *priv;
   2053 } camera3_device_t;
   2054 
   2055 __END_DECLS
   2056 
   2057 #endif /* #ifdef ANDROID_INCLUDE_CAMERA3_H */
   2058