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