Camera: add OFFLINE_PROCESSING APIs

Also a typo fix in metadata doc.

Test: N/A. New API skeleton, no implementation yet.
Bug: 135142453
Change-Id: I4852ee28242afabe81b02cfef39994c5d2705359
diff --git a/camera/device/3.6/Android.bp b/camera/device/3.6/Android.bp
new file mode 100644
index 0000000..8766b93
--- /dev/null
+++ b/camera/device/3.6/Android.bp
@@ -0,0 +1,24 @@
+// This file is autogenerated by hidl-gen -Landroidbp.
+
+hidl_interface {
+    name: "android.hardware.camera.device@3.6",
+    root: "android.hardware",
+    vndk: {
+        enabled: true,
+    },
+    srcs: [
+        "types.hal",
+        "ICameraDeviceSession.hal",
+        "ICameraOfflineSession.hal",
+    ],
+    interfaces: [
+        "android.hardware.camera.common@1.0",
+        "android.hardware.camera.device@3.2",
+        "android.hardware.camera.device@3.3",
+        "android.hardware.camera.device@3.4",
+        "android.hardware.camera.device@3.5",
+        "android.hardware.graphics.common@1.0",
+        "android.hidl.base@1.0",
+    ],
+    gen_java: false,
+}
diff --git a/camera/device/3.6/ICameraDeviceSession.hal b/camera/device/3.6/ICameraDeviceSession.hal
new file mode 100644
index 0000000..00ebcc3
--- /dev/null
+++ b/camera/device/3.6/ICameraDeviceSession.hal
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.camera.device@3.6;
+
+import android.hardware.camera.common@1.0::Status;
+import @3.5::ICameraDeviceSession;
+import @3.5::StreamConfiguration;
+import ICameraOfflineSession;
+
+/**
+ * Camera device active session interface.
+ *
+ * Obtained via ICameraDevice::open(), this interface contains the methods to
+ * configure and request captures from an active camera device.
+ */
+interface ICameraDeviceSession extends @3.5::ICameraDeviceSession {
+    /**
+     * configureStreams_3_6:
+     *
+     * Identical to @3.5::ICameraDeviceSession.configureStreams, except that:
+     *
+     * - a boolean supportOffline is added to HalStreamConfiguration to indicate
+     *   if this stream can be switched to offline mode later.
+     *
+     * @return status Status code for the operation, one of:
+     *     OK:
+     *         On successful stream configuration.
+     *     INTERNAL_ERROR:
+     *         If there has been a fatal error and the device is no longer
+     *         operational. Only close() can be called successfully by the
+     *         framework after this error is returned.
+     *     ILLEGAL_ARGUMENT:
+     *         If the requested stream configuration is invalid. Some examples
+     *         of invalid stream configurations include:
+     *           - Including more than 1 INPUT stream
+     *           - Not including any OUTPUT streams
+     *           - Including streams with unsupported formats, or an unsupported
+     *             size for that format.
+     *           - Including too many output streams of a certain format.
+     *           - Unsupported rotation configuration
+     *           - Stream sizes/formats don't satisfy the
+     *             StreamConfigurationMode requirements
+     *             for non-NORMAL mode, or the requested operation_mode is not
+     *             supported by the HAL.
+     *           - Unsupported usage flag
+     *         The camera service cannot filter out all possible illegal stream
+     *         configurations, since some devices may support more simultaneous
+     *         streams or larger stream resolutions than the minimum required
+     *         for a given camera device hardware level. The HAL must return an
+     *         ILLEGAL_ARGUMENT for any unsupported stream set, and then be
+     *         ready to accept a future valid stream configuration in a later
+     *         configureStreams call.
+     * @return halConfiguration The stream parameters desired by the HAL for
+     *     each stream, including maximum buffers, the usage flags, and the
+     *     override format.
+     */
+    configureStreams_3_6(@3.5::StreamConfiguration requestedConfiguration)
+        generates (Status status, HalStreamConfiguration halConfiguration);
+
+    /**
+     * switchToOffline:
+     *
+     * Switch the current running session from actively streaming mode to the
+     * offline mode. See ICameraOfflineSession for more details.
+     *
+     * The streamsToKeep argument contains list of streams IDs where application
+     * still needs its output. For all streams application does not need anymore,
+     * camera HAL can send ERROR_BUFFER to speed up the transition, or even send
+     * ERROR_REQUEST if all output targets of a request is not needed. By the
+     * time this call returns, camera HAL must have returned all buffers coming
+     * from streams no longer needed and have erased buffer caches of such streams.
+     *
+     * For all requests that are going to be transferred to offline session,
+     * the ICameraDeviceSession is responsible to capture all input buffers from
+     * the image sensor before the switchToOffline call returns. Before
+     * switchToOffline returns, camera HAL must have completed all requests not
+     * switching to offline mode, and collected information on what streams and
+     * requests are going to continue in the offline session, in the
+     * offlineSessionInfo output argument.
+     *
+     * If there are no requests qualified to be transferred to offline session,
+     * the camera HAL must return a null ICameraOfflineSession object with OK
+     * status. In this scenario, the camera HAL still must flush all inflight
+     * requests and unconfigure all streams before returning this call.
+     *
+     * After switchToOffline returns, the ICameraDeviceSession must be back to
+     * unconfigured state as if it is just created and no streams are configured.
+     * Also, camera HAL must not call any methods in ICameraDeviceCallback since
+     * all unfinished requests are now transferred to the offline session.
+     * After the call returns, camera service may then call close to close
+     * the camera device, or call configureStream* again to reconfigure the
+     * camera and then send new capture requests with processCaptureRequest. In
+     * the latter case, it is legitimate for camera HAL to call methods in
+     * ICameraDeviceCallback again in response to the newly submitted capture
+     * requests.
+     *
+     * @return status Status code for the operation, one of:
+     *     OK:
+     *         On switching to offline session and unconfiguring streams
+     *         successfully.
+     *     ILLEGAL_ARGUMENT:
+     *         If camera does not support offline mode in any one of streams
+     *         in streamsToKeep argument. Note that the camera HAL must report
+     *         if a stream supports offline mode in HalStreamConfiguration
+     *         output of configureStreams_3_6 method. If all streams in
+     *         streamsToKeep argument support offline mode, then the camera HAL
+     *         must not return this error.
+     *
+     *
+     * @return offlineSessionInfo Information on what streams and requests will
+     *     be transferred to offline session to continue processing.
+     *
+     * @return offlineSession The offline session object camera service will use
+     *     to interact with.
+     */
+    switchToOffline(vec<int32_t> streamsToKeep) generates (Status status,
+        CameraOfflineSessionInfo offlineSessionInfo, ICameraOfflineSession offlineSession);
+};
diff --git a/camera/device/3.6/ICameraOfflineSession.hal b/camera/device/3.6/ICameraOfflineSession.hal
new file mode 100644
index 0000000..03cea64
--- /dev/null
+++ b/camera/device/3.6/ICameraOfflineSession.hal
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.camera.device@3.6;
+
+import @3.5::ICameraDeviceCallback;
+
+/**
+ * Camera device offline session interface.
+ *
+ * Obtained via ICameraDeviceSession::switchToOffline(), this interface contains
+ * the methods and callback interfaces that define how camera service interacts
+ * with an offline session.
+ *
+ * An offline session contains some unfinished capture requests that were submitted
+ * to the parent ICameraDeviceSession before calling switchToOffline, and is
+ * responsible for delivering these capture results back to camera service regardless
+ * of whether the parent camera device is still opened or not. An offline session must
+ * not have access to the camera device's image sensor. During switchToOffline
+ * call, camera HAL must capture all necessary frames from the image sensor that
+ * is needed for completing the requests offline later.
+ */
+interface ICameraOfflineSession {
+    /**
+     * Set the callbacks for offline session to communicate with camera service.
+     *
+     * Offline session is responsible to store all callbacks the camera HAL
+     * generated after the return of ICameraDeviceSession::switchToOffline, and
+     * send them to camera service once this method is called.
+     *
+     * Camera service must not call this method more than once, so these
+     * callbacks can be assumed to be constant after the first setCallback call.
+     */
+    setCallback(ICameraDeviceCallback cb);
+
+    /**
+     * getCaptureResultMetadataQueue:
+     *
+     * Retrieves the queue used along with
+     * ICameraDeviceCallback#processCaptureResult.
+     *
+     * Clients to ICameraOfflineSession must:
+     * - Call getCaptureRequestMetadataQueue to retrieve the fast message queue;
+     * - In implementation of ICameraDeviceCallback, test whether
+     *   .fmqResultSize field is zero.
+     *     - If .fmqResultSize != 0, read result metadata from the fast message
+     *       queue;
+     *     - otherwise, read result metadata in CaptureResult.result.
+     *
+     * @return queue the queue that implementation writes result metadata to.
+     */
+    getCaptureResultMetadataQueue() generates (fmq_sync<uint8_t> queue);
+
+    /**
+     * Close the offline session and release all resources.
+     *
+     * Camera service may call this method before or after the offline session
+     * has finished all requests it needs to handle. If there are still unfinished
+     * requests when close is called, camera HAL must send ERROR_REQUEST for
+     * all unfinished requests and return all buffers via
+     * ICameraDeviceCallback#processCaptureResult or
+     * ICameraDeviceCallback#returnStreamBuffers.
+     * Also, all buffer caches maintained by the offline session must be erased
+     * before the close call returns.
+     */
+    close();
+};
diff --git a/camera/device/3.6/types.hal b/camera/device/3.6/types.hal
new file mode 100644
index 0000000..743b139
--- /dev/null
+++ b/camera/device/3.6/types.hal
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.camera.device@3.6;
+
+import @3.2::BufferCache;
+import @3.4::HalStream;
+
+/**
+ * OfflineRequest:
+ *
+ * Information about a capture request being switched to offline mode via the
+ * ICameraDeviceSession#switchToOffline method.
+ *
+ */
+struct OfflineRequest {
+    /**
+     * Must match a inflight CaptureRequest sent by camera service
+     */
+    uint32_t frameNumber;
+
+    /**
+     * Stream IDs for outputs that will be returned via ICameraDeviceCallback.
+     * The stream ID must be within one of offline stream listed in
+     * CameraOfflineSessionInfo.
+     * Camera service will validate these pending buffers are matching camera
+     * service's record to make sure no buffers are leaked during the
+     * switchToOffline call.
+     */
+    vec<int32_t> pendingStreams;
+};
+
+/**
+ * OfflineStream:
+ *
+ * Information about a stream being switched to offline mode via the
+ * ICameraDeviceSession#switchToOffline method.
+ *
+ */
+struct OfflineStream {
+    /**
+     * IDs of a stream to be transferred to offline session.
+     *
+     * For devices that do not support HAL buffer management, this must be
+     * one of stream ID listed in streamsToKeep argument of the
+     * switchToOffline call.
+     * For devices that support HAL buffer management, this could be any stream
+     * that was configured right before calling switchToOffline.
+     */
+    int32_t id;
+
+    /**
+     * Number of outstanding buffers that will be returned via offline session
+     */
+    uint32_t numOutstandingBuffers;
+
+    /**
+     * Buffer ID of buffers currently cached between camera service and this
+     * stream, which may or may not be owned by the camera HAL right now.
+     * See StreamBuffer#bufferId for more details.
+     */
+    vec<uint64_t> circulatingBufferIds;
+};
+
+/**
+ * CameraOfflineSessionInfo:
+ *
+ * Information about pending outputs that's being transferred to an offline
+ * session from an active session using the
+ * ICameraDeviceSession#switchToOffline method.
+ *
+ */
+struct CameraOfflineSessionInfo {
+    /**
+     * Information on what streams will be preserved in offline session.
+     * Streams not listed here will be removed by camera service after
+     * switchToOffline call returns.
+     */
+    vec<OfflineStream> offlineStreams;
+
+    /**
+     * Information for requests that will be handled by offline session
+     * Camera service will validate this matches what camera service has on
+     * record.
+     */
+    vec<OfflineRequest> offlineRequests;
+};
+
+/**
+ * HalStream:
+ *
+ * The camera HAL's response to each requested stream configuration.
+ *
+ * This version extends the @3.4 HalStream with the physicalCameraId
+ * field
+ */
+struct HalStream {
+    /**
+     * The definition of HalStream from the prior version.
+     */
+    @3.4::HalStream v3_4;
+
+    /**
+     * Whether this stream can be switch to offline mode.
+     *
+     * For devices that does not support the OFFLINE_PROCESSING capability, this
+     * fields will always be false.
+     *
+     * For devices support the OFFLINE_PROCESSING capability: any input stream
+     * and any output stream that can be output of the input stream must set
+     * this field to true. Also any stream of YUV420_888 format or JPEG format,
+     * with CPU_READ usage flag, must set this field to true. All other streams
+     * are up to camera HAL to advertise support or not, though it is not
+     * recommended to list support for streams with hardware composer or video
+     * encoder usage flags as these streams tend to be targeted continuously and
+     * can lead to long latency when trying to switch to offline.
+     *
+     */
+    bool supportOffline;
+};
+
+/**
+ * HalStreamConfiguration:
+ *
+ * Identical to @3.4::HalStreamConfiguration, except that it contains @3.6::HalStream entries.
+ *
+ */
+struct HalStreamConfiguration {
+    vec<HalStream> streams;
+};