xref: /aosp_15_r20/hardware/interfaces/automotive/evs/1.0/IEvsCamera.hal (revision 4d7e907c777eeecc4c5bd7cf640a754fac206ff7)

/*
 * Copyright (C) 2016 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 [email protected];

import IEvsCameraStream;


/**
 * Represents a single camera and is the primary interface for capturing images.
 */
interface IEvsCamera {

    /**
     * Returns the ID of this camera.
     *
     * @return info The description of this camera.  This must be the same value as
     *              reported by EvsEnumerator::getCameraList().
     */
    getCameraInfo() generates (CameraDesc info);

    /**
     * Specifies the depth of the buffer chain the camera is asked to support.
     *
     * Up to this many frames may be held concurrently by the client of IEvsCamera.
     * If this many frames have been delivered to the receiver without being returned
     * by doneWithFrame, the stream must skip frames until a buffer is returned for reuse.
     * It is legal for this call to come at any time, even while streams are already running,
     * in which case buffers should be added or removed from the chain as appropriate.
     * If no call is made to this entry point, the IEvsCamera must support at least one
     * frame by default. More is acceptable.
     *
     * @param  bufferCount Number of buffers the client of IEvsCamera may hold concurrently.
     * @return result EvsResult::OK is returned if this call is successful.
     */
    setMaxFramesInFlight(uint32_t bufferCount) generates (EvsResult result);

    /**
     * Request to start EVS camera stream from this camera.
     *
     * The IEvsCameraStream must begin receiving calls with various events
     * including new image frame ready until stopVideoStream() is called.
     *
     * @param  receiver IEvsCameraStream implementation.
     * @return result EvsResult::OK is returned if this call is successful.
     */
    startVideoStream(IEvsCameraStream receiver) generates (EvsResult result);

    /**
     * Return a frame that was delivered by to the IEvsCameraStream.
     *
     * When done consuming a frame delivered to the IEvsCameraStream
     * interface, it must be returned to the IEvsCamera for reuse.
     * A small, finite number of buffers are available (possibly as small
     * as one), and if the supply is exhausted, no further frames may be
     * delivered until a buffer is returned.
     *
     * @param  buffer A buffer to be returned.
     */
    oneway doneWithFrame(BufferDesc buffer);

    /**
     * Stop the delivery of EVS camera frames.
     *
     * Because delivery is asynchronous, frames may continue to arrive for
     * some time after this call returns. Each must be returned until the
     * closure of the stream is signaled to the IEvsCameraStream.
     * This function cannot fail and is simply ignored if the stream isn't running.
     */
    stopVideoStream();

    /**
     * Request driver specific information from the HAL implementation.
     *
     * The values allowed for opaqueIdentifier are driver specific,
     * but no value passed in may crash the driver. The driver should
     * return 0 for any unrecognized opaqueIdentifier.
     *
     * @param  opaqueIdentifier An unique identifier of the information to
     *                          request.
     * @return value            Requested information.  Zero is returned if the
     *                          driver does not recognize a given identifier.
     */
    getExtendedInfo(uint32_t opaqueIdentifier) generates (int32_t value);

    /**
     * Send a driver specific value to the HAL implementation.
     *
     * This extension is provided to facilitate car specific
     * extensions, but no HAL implementation may require this call
     * in order to function in a default state.
     * INVALID_ARG is returned if the opaqueValue is not meaningful to
     * the driver implementation.
     *
     * @param  opaqueIdentifier An unique identifier of the information to
     *                          program.
     *         opaqueValue      A value to program.
     * @return result           EvsResult::OK is returned if this call is successful.
     */
    setExtendedInfo(uint32_t opaqueIdentifier, int32_t opaqueValue) generates (EvsResult result);
};