automotive/evs/1.0/types.hal

/*
 * 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 android.hardware.automotive.evs@1.0;


/**
 * Structure describing the basic properties of an EVS camera
 *
 * The HAL is responsible for filling out this structure for each
 * EVS camera in the system.
 */
struct CameraDesc {
    /* Unique identifier for camera devices.  This may be a path to detected
     * camera device; for example, "/dev/video0".
     */
    string      cameraId;

    /* Opaque value from driver.  Vendor may use this field to store additional
     * information; for example, sensor and bridge chip id.
     */
    uint32_t    vendorFlags;
};


/**
 * Structure describing the basic properties of an EVS display
 *
 * The HAL is responsible for filling out this structure to describe
 * the EVS display. As an implementation detail, this may be a physical
 * display or a virtual display that is overlaid or mixed with another
 * presentation device.
 */
struct DisplayDesc {
    /* Unique identifier for the display */
    string      displayId;

    /* Opaque value from driver */
    uint32_t    vendorFlags;
};


/**
 * Structure representing an image buffer through our APIs
 *
 * In addition to the handle to the graphics memory, we need to retain
 * the properties of the buffer for easy reference and reconstruction of
 * an ANativeWindowBuffer object on the remote side of API calls.
 * (Not least because OpenGL expect an ANativeWindowBuffer* for us as a
 * texture via eglCreateImageKHR().
 * See also related types from android.hardware.graphics.common
 * TODO:  b/34722508  Review details of interaction of this structure with gralloc and OpenGL.
 *        Specifically consider if format and/or usage should become enumerated types.
 */
struct BufferDesc {
    /* A frame width in the units of pixels */
    uint32_t    width;

    /* A frame height in the units of pixels */
    uint32_t    height;

    /* A frame stride in the units of pixels, to match gralloc */
    uint32_t    stride;

    /* The size of a pixel in the units of bytes */
    uint32_t    pixelSize;

    /* The image format of the frame; may contain values from
     * android_pixel_format_t
     */
    uint32_t    format;

    /* May contain values from Gralloc.h */
    uint32_t    usage;

    /* Opaque value from driver */
    uint32_t    bufferId;

    /* Gralloc memory buffer handle */
    handle      memHandle;
};


/**
 * States for control of the EVS display
 *
 * The DisplayInfo structure describes the basic properties of an EVS display. Any EVS
 * implementation is required to have one. The HAL is responsible for filling out this
 * structure to describe the EVS display. As an implementation detail, this may be a
 * physical display or a virtual display that is overlaid or mixed with another
 * presentation device.
 */
enum DisplayState : uint32_t {
    /* Display has not been requested by any application yet */
    NOT_OPEN = 0,

    /* Display is inhibited */
    NOT_VISIBLE,

    /* Will become visible with next frame */
    VISIBLE_ON_NEXT_FRAME,

    /* Display is currently active */
    VISIBLE,

    /* Driver is in an undefined state.  Interface should be closed. */
    DEAD,

    /* Must be the last */
    NUM_STATES
};


/** Error codes used in EVS HAL interface. */
enum EvsResult : uint32_t {
    OK = 0,
    INVALID_ARG,
    STREAM_ALREADY_RUNNING,
    BUFFER_NOT_AVAILABLE,
    OWNERSHIP_LOST,
    UNDERLYING_SERVICE_ERROR,
};