automotive/can/1.0/ICanController.hal

/*
 * 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.automotive.can@1.0;

/**
 * Represents a CAN controller that's capable of configuring CAN bus interfaces.
 *
 * The goal of this service is to configure CAN interfaces and bring up HIDL
 * server instances of ICanBus for each one that's up.
 *
 * Providing an ICanController interface to configure CAN buses is optional.
 * A system can elect to publish only ICanBus if the hardware is hardcoded
 * for a specific application.
 */
interface ICanController {
    /**
     * Type of an interface, a mean to express the domain of device address.
     */
    enum InterfaceType : uint8_t {
        /**
         * Virtual SocketCAN interface.
         *
         * The address is an interface name, such as vcan0. If the interface
         * doesn't exist, HAL server must create it.
         *
         * Valid InterfaceIdentifier types:
         *  - address.
         */
        VIRTUAL,

        /**
         * Native SocketCAN interface.
         *
         * The address is an interface name, such as can0.
         *
         * Valid InterfaceIdentifier types:
         *  - address;
         *  - serialno.
         */
        SOCKETCAN,

        /**
         * Serial-based interface.
         *
         * The address is a patch to a device, such as /dev/ttyUSB0.
         *
         * Valid InterfaceIdentifier types:
         *  - address;
         *  - serialno.
         */
        SLCAN,

        /**
         * Proprietary interface, specific to the hardware system Android
         * is running on. Instead of using address field, the interface is
         * addressed with 0-based index.
         *
         * Valid InterfaceIdentifier types:
         *  - index
         */
        INDEXED
    };

    enum Result : uint8_t {
        OK,

        /**
         * General error class, if others are not applicable.
         */
        UNKNOWN_ERROR,

        /**
         * Up request was called out of order (i.e. trying to up the
         * interface twice).
         */
        INVALID_STATE,

        /** Interface type is not supported. */
        NOT_SUPPORTED,

        /**
         * Provided address (interface name, device path) doesn't exist or there
         * is no device with a given serial no.
         */
        BAD_ADDRESS,

        /** Provided baud rate is not supported by the hardware. */
        BAD_BAUDRATE,
    };

    /**
     * Configuration of the (physical or virtual) CAN bus.
     *
     * ISO TP and CAN FD are currently not supported.
     */
    struct BusConfiguration {
        /**
         * Name under which ICanBus HIDL service should be published.
         *
         * It must consist of only alphanumeric characters and underscore
         * (a-z, A-Z, 0-9, '_'), at least 1 and at most 32 characters long.
         */
        string name;

        /**
         * Type of the hardware (or virtual) CAN interface.
         */
        InterfaceType iftype;

        /**
         * Identification of hardware interface to configure.
         */
        safe_union InterfaceIdentifier {
            /**
             * Interface name or other mean of identification of the specific
             * interface port. Syntax depends on {@see iftype}, for details
             * {@see InterfaceType}.
             */
            string address;

            /**
             * Numerical identifier of interface, used for InterfaceType#INDEXED.
             */
            uint8_t index;

            /**
             * Alternatively to providing {@see address}, one may provide a list
             * of interface serial number suffixes. If there happens to be
             * a device (like USB2CAN) with a matching serial number suffix,
             * it gets selected.
             *
             * Client may utilize this in two ways: by matching against the
             * entire serial number, or the last few characters (usually one).
             * The former is better for small-scale test deployments (with just
             * a handful of vehicles), the latter is good for larger scale
             * (where a small suffix list may support large test fleet).
             */
            vec<string> serialno;
        } interfaceId;

        /**
         * Baud rate for CAN communication.
         *
         * Typical baud rates are: 100000, 125000, 250000, 500000.
         *
         * For virtual interfaces this value is ignored.
         */
        uint32_t baudrate;
    };

    /**
     * Fetches the list of interface types supported by this HAL server.
     *
     * @return iftypes The list of supported interface types
     */
    getSupportedInterfaceTypes() generates (vec<InterfaceType> iftypes);

    /**
     * Bring up the CAN interface and publish ICanBus server instance.
     *
     * @param config Configuration of the CAN interface
     * @return result OK if the operation succeeded; error code otherwise.
     */
    upInterface(BusConfiguration config) generates (Result result);

    /**
     * Unpublish ICanBus server instance and bring down the CAN interface.
     *
     * In case of failure, at least the ICanBus server instance must be
     * unpublished and resources freed on best-effort basis.
     *
     * @param name Name of the interface (@see BusConfiguration#name} to
     * bring down
     * @return success true in case of success, false otherwise
     */
    downInterface(string name) generates (bool success);
};