platform_hardware_interfaces/automotive/can/1.0/ICanBus.hal
Tomasz Wasilczyk a90619662b Improve error handling with separate ICanErrorListener
Error handling highlights:
- moved onError from ICanMessageListener to ICanErrorListener
- added isFatal callback argument to request client disconnect
- don't down interface that's already down

Also:
- don't crash if it's not possible to unregister ICanBus
- don't crash while trying to down interface that failed
- make hidl-utils available to vendor libraries

Bug: 143779011
Test: implemented a VHAL service prototype that communicates with this HAL
Change-Id: I98d054da9da0ead5ef952aebc086e052ac996212
2019-11-06 14:52:07 -08:00

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/*
* 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;
import ICanErrorListener;
import ICanMessageListener;
import ICloseHandle;
/**
* Represents a CAN bus interface that's up and configured.
*
* Configuration part is done in ICanController.
*/
interface ICanBus {
/**
* Send CAN message.
*
* @param message CAN message to send out
* @return result OK in the case of success
* PAYLOAD_TOO_LONG if the payload is too long
* INTERFACE_DOWN if the bus is down
* TRANSMISSION_FAILURE in case of transmission failure
*/
send(CanMessage message) generates (Result result);
/**
* Requests HAL implementation to listen for specific CAN messages.
*
* HAL is responsible for maintaining listener set and sending out messages
* to each listener that matches given filter against received message.
*
* Empty filter list means no filtering. If two or more listeners requested
* different filters, HAL server must merge these to fulfill the superset of
* these filters. HAL must not send out a message to a listener which filter
* doesn't match given message id.
*
* If filtering is not supported at the hardware level (what's strongly
* recommended), it must be covered in the HAL.
*
* @param filter The set of requested filters
* @param listener The interface to receive the messages on
* @return result OK in the case of success
* INTERFACE_DOWN if the bus is down
* @return close A handle to call in order to remove the listener
*/
listen(vec<CanMessageFilter> filter, ICanMessageListener listener)
generates (Result result, ICloseHandle close);
/**
* Adds a new listener for CAN bus or interface errors.
*
* If the error is fatal, the client is supposed to drop any references to
* this specific ICanBus instance (see ICanErrorListener).
*
* @param listener The interface to receive the error events on
* @return close A handle to call in order to remove the listener
*/
listenForErrors(ICanErrorListener listener) generates (ICloseHandle close);
};