前言
前面的文章中，描述了 Android Automotive 的框架中应用、Framework 层服务等知识，本篇文章将会继续按照 Android Automotive 框架介绍 Vehicle Hal 层服务的内容。
上一篇：AndroidAutomotive模块介绍（三）CarService服务文章来源地址https://www.toymoban.com/news/detail-849772.html
正文
1、VehicleHal 介绍
本篇文档将对 Andorid Automotive 框架中 VehicleHal 层展开介绍。VehicleHal 即为车辆硬件抽象层的定义。可以理解为 Android Automotive OS 中的硬件抽象层接口，包括车辆属性和方法；各厂商制造商会根据定义的 Hal 接口，实现定制化的模块服务。
VehicleHal 是链接 Android Automotive Car Services 与制造商实现车辆控制服务进程的桥梁，通过标准化接口对上层提供服务，对于服务的实现依赖厂商的定制化，可以忽略汽车制造商的具体实现，也就是说 CarService 调用 VehicleHal 定义的标准接口，厂商实现这些接口。
2、VehicleHal 模块功能
2.1 rc 文件
VehicleHal 的代码路径为：android/hardware/interfaces/automotive/vehicle/2.0/default。路径下有 android.hardware.automotive.vehicle@2.0-service.rc 文件，在开机阶段通过此 rc 文件，将 VehicleHal 进程启动，下面来看下 android.hardware.automotive.vehicle@2.0-service.rc 文件的定义
service vendor.vehicle-hal-2.0 /vendor/bin/hw/android.hardware.automotive.vehicle@2.0-service
class hal
user vehicle_network
group system inet
2.2 编译
对于 VehicleHal 的编译，可以对以下两个 Android.bp 文件介绍。
- Hidl 接口编译
- VehicleHal 服务编译
VehicleHal 定义的 Hal 接口编译介绍，Android.bp 文件路径为：android/hardware/interfaces/automotive/vehicle/2.0，目录结构如下：
ubuntu:android/hardware/interfaces/automotive/vehicle/2.0$ ls -l
total 132
-rw-r--r-- 1 users 375 Nov 9 2022 Android.bp
drwxrwxr-x 5 users 4096 Mar 22 13:55 default
-rw-r--r-- 1 users 2336 Nov 9 2022 IVehicleCallback.hal
-rw-r--r-- 1 users 3665 Nov 9 2022 IVehicle.hal
-rw-r--r-- 1 users 115184 Nov 9 2022 types.hal
下面是 Android.bp 文件的定义：
// This file is autogenerated by hidl-gen -Landroidbp.
hidl_interface {
name: "android.hardware.automotive.vehicle@2.0",
root: "android.hardware",
vndk: {
enabled: true,
},
srcs: [
"types.hal",
"IVehicle.hal",
"IVehicleCallback.hal",
],
interfaces: [
"android.hidl.base@1.0",
],
gen_java: true,
}
编译文件中定义了 android.hardware.automotive.vehicle@2.0 HIDL 接口编译，包含三个文件 types.hal、IVehicle.hal、IVehicleCallback.hal 文件。
VehicleHal 服务编译介绍，Android.bp 文件路径为：android/hardware/interfaces/automotive/vehicle/2.0/default，目录结构如下：
ubuntu16:android/hardware/interfaces/automotive/vehicle/2.0/default$ ls -l
total 28
-rw-r--r-- 1 users 4705 Nov 9 2022 Android.bp
-rw-r--r-- 1 users 155 Nov 9 2022 android.hardware.automotive.vehicle@2.0-service.rc
drwxrwxr-x 4 users 4096 Jun 7 2022 common
drwxrwxr-x 3 users 4096 Jun 7 2022 impl
drwxrwxr-x 2 users 4096 Nov 9 2022 tests
-rw-r--r-- 1 users 1953 Nov 9 2022 VehicleService.cpp
Android.bp 文件定义如下：
// Vehicle reference implementation lib
cc_library {
name: "android.hardware.automotive.vehicle@2.0-manager-lib",
vendor: true,
defaults: ["vhal_v2_0_defaults"],
srcs: [
"common/src/Obd2SensorStore.cpp",
"common/src/SubscriptionManager.cpp",
"common/src/VehicleHalManager.cpp",
"common/src/VehicleObjectPool.cpp",
"common/src/VehiclePropertyStore.cpp",
"common/src/VehicleUtils.cpp",
"common/src/VmsUtils.cpp",
],
local_include_dirs: ["common/include/vhal_v2_0"],
export_include_dirs: ["common/include"],
}
// Vehicle default VehicleHAL implementation
cc_library_static {
name: "android.hardware.automotive.vehicle@2.0-default-impl-lib",
vendor: true,
cflags: ["-Wno-unused-parameter", "-Wno-sign-compare"],
defaults: ["vhal_v2_0_defaults"],
srcs: [
"impl/vhal_v2_0/CommConn.cpp",
"impl/vhal_v2_0/EmulatedVehicleHal.cpp",
"impl/vhal_v2_0/VehicleEmulator.cpp",
"impl/vhal_v2_0/PipeComm.cpp",
"impl/vhal_v2_0/SocketComm.cpp",
"impl/vhal_v2_0/LinearFakeValueGenerator.cpp",
"impl/vhal_v2_0/JsonFakeValueGenerator.cpp",
],
local_include_dirs: ["common/include/vhal_v2_0"],
export_include_dirs: ["impl"],
whole_static_libs: ["android.hardware.automotive.vehicle@2.0-manager-lib"],
shared_libs: [
"libbase",
"libprotobuf-cpp-lite",
],
static_libs: [
"libjsoncpp",
"libqemu_pipe",
"android.hardware.automotive.vehicle@2.0-libproto-native",
],
}
cc_binary {
name: "android.hardware.automotive.vehicle@2.0-service",
defaults: ["vhal_v2_0_defaults"],
init_rc: ["android.hardware.automotive.vehicle@2.0-service.rc"],
vendor: true,
relative_install_path: "hw",
srcs: ["VehicleService.cpp"],
shared_libs: [
"libbase",
"libprotobuf-cpp-lite",
],
static_libs: [
"android.hardware.automotive.vehicle@2.0-manager-lib",
"android.hardware.automotive.vehicle@2.0-default-impl-lib",
"android.hardware.automotive.vehicle@2.0-libproto-native",
"libjsoncpp",
"libqemu_pipe",
],
}
从 Android.bp 的定义中，VehicleHal 的服务名为 android.hardware.automotive.vehicle@2.0-service，启动 rc 文件是 android.hardware.automotive.vehicle@2.0-service.rc，入口文件是 VehicleService.cpp，依赖自定义相关模块主要有 android.hardware.automotive.vehicle@2.0-manager-lib、android.hardware.automotive.vehicle@2.0-default-impl-lib、android.hardware.automotive.vehicle@2.0-libproto-native。
android.hardware.automotive.vehicle@2.0-manager-lib 模块是 common 目录下的文件所编译的内容，主要是 VehicleHal 所以来的模块。
android.hardware.automotive.vehicle@2.0-default-impl-lib 模块是 impl 目录下的文件所编译的内容，主要是 VehicleHal 的功能实现模块。
android.hardware.automotive.vehicle@2.0-libproto-native 模块是 impl/vhal_v2_0/proto 目录下的文件所编译的内容，目录下的文件为 VehicleHalProto.proto 文件，是一种序列化存储数据的方式。
2.3 HIDL 接口
Android Automotive 框架中 Hal 层接口文件有三个，IVehicle.hal、IVehicleCallback.hal 和 types.hal 文件。IVehicle.hal 文件中定义了 Vehicle Hal 对外提供的接口；IVehicleCallback.hal 文件中定义了 VehicleHal 的回调接口；types.hal 文件定义了 Vehicle Hal 的属性定义。
Hidl 文件路径为：android/hardware/interfaces/automotive/vehicle/2.0。
2.3.1 IVehicle.hal
IVehicle.hal 文件中定义了 Vehicle Hal 对外提供的接口，上层 CarService 通过 IVehicle.hal 中定义的接口与 Vehicle Hal 通信。
package android.hardware.automotive.vehicle@2.0;
import IVehicleCallback;
interface IVehicle {
/**
* Returns a list of all property configurations supported by this vehicle
* HAL.
* 返回此车辆HAL支持的所有属性配置的列表
*/
getAllPropConfigs() generates (vec<VehiclePropConfig> propConfigs);
/**
* Returns a list of property configurations for given properties.
*
* If requested VehicleProperty wasn't found it must return
* StatusCode::INVALID_ARG, otherwise a list of vehicle property
* configurations with StatusCode::OK
* 返回给定属性的属性配置列表。
* 如果请求的车辆属性没有找到，它必须返回StatusCode::INVALID_ARG，否则返回一个车辆属性配置列表，StatusCode::OK
*/
getPropConfigs(vec<int32_t> props)
generates (StatusCode status, vec<VehiclePropConfig> propConfigs);
/**
* Get a vehicle property value.
*
* For VehiclePropertyChangeMode::STATIC properties, this method must always
* return the same value always.
* For VehiclePropertyChangeMode::ON_CHANGE properties, it must return the
* latest available value.
*
* Some properties like RADIO_PRESET requires to pass additional data in
* GET request in VehiclePropValue object.
*
* If there is no data available yet, which can happen during initial stage,
* this call must return immediately with an error code of
* StatusCode::TRY_AGAIN.
* 获取车辆属性值。
* 对于 VehiclePropertyChangeMode::STATIC 的属性值，此方法会返回同一个值，不会改变。
* 对于 VehiclePropertyChangeMode::ON_CHANGE 的属性值，此方法会返回最新值。
*/
get(VehiclePropValue requestedPropValue)
generates (StatusCode status, VehiclePropValue propValue);
/**
* Set a vehicle property value.
*
* Timestamp of data must be ignored for set operation.
*
* Setting some properties require having initial state available. If initial
* data is not available yet this call must return StatusCode::TRY_AGAIN.
* For a property with separate power control this call must return
* StatusCode::NOT_AVAILABLE error if property is not powered on.
* 设置车辆属性值。
* 特殊场景：
* 设置一些属性值需要其初始状态可用，如果初始状态不可用，需要返回 StatusCode::TRY_AGAIN。
* 设置单独电源控制的属性，如果属性未上电，需要返回 StatusCode::TRY_AGAIN。
*/
set(VehiclePropValue propValue) generates (StatusCode status);
/**
* Subscribes to property events.
*
* Clients must be able to subscribe to multiple properties at a time
* depending on data provided in options argument.
*
* @param listener This client must be called on appropriate event.
* @param options List of options to subscribe. SubscribeOption contains
* information such as property Id, area Id, sample rate, etc.
* 订阅属性
* 客户端可以一次订阅多个属性，这取决于 options 定义的参数。
* 参数 SubscribeOptions 包含 属性id、区域id、采样率 等信息。
*/
subscribe(IVehicleCallback callback, vec<SubscribeOptions> options)
generates (StatusCode status);
/**
* Unsubscribes from property events.
*
* If this client wasn't subscribed to the given property, this method
* must return StatusCode::INVALID_ARG.
* 取消订阅属性
* 如果客户端在此前没有对此属性进行订阅，则返回 StatusCode::INVALID_ARG。
*/
unsubscribe(IVehicleCallback callback, int32_t propId)
generates (StatusCode status);
/**
* Print out debugging state for the vehicle hal.
*
* The text must be in ASCII encoding only.
*
* Performance requirements:
*
* The HAL must return from this call in less than 10ms. This call must avoid
* deadlocks, as it may be called at any point of operation. Any synchronization
* primitives used (such as mutex locks or semaphores) must be acquired
* with a timeout.
*
* 打印车辆的调试状态。
*/
debugDump() generates (string s);
};
2.3.2 IVehicleCallback.hal
IVehicleCallback.hal 文件定义了 VehicleHal 的回调对象，上层 CarService 通过注册此回调对象以监听属性是否改变。VehicleHal 通过回调对象返回状态给到客户端。
package android.hardware.automotive.vehicle@2.0;
interface IVehicleCallback {
/**
* Event callback happens whenever a variable that the API user has
* subscribed to needs to be reported. This may be based purely on
* threshold and frequency (a regular subscription, see subscribe call's
* arguments) or when the IVehicle#set method was called and the actual
* change needs to be reported.
*
* These callbacks are chunked.
*
* @param values that has been updated.
* 当需要报告客户端订阅的变量时，就会调用此回调函数。
* 这可能基于常规按频率上报或者客户端调用 IVehicle#set 函数时调用。
*/
oneway onPropertyEvent(vec<VehiclePropValue> propValues);
/**
* This method gets called if the client was subscribed to a property using
* SubscribeFlags::EVENTS_FROM_ANDROID flag and IVehicle#set(...) method was called.
*
* These events must be delivered to subscriber immediately without any
* batching.
*
* @param value Value that was set by a client.
* 如果客户端使用 SubscribeFlags::EVENTS_FROM_ANDROID 标志订阅属性，并且调用 IVehicle#set 函数，则回调此方法。
*/
oneway onPropertySet(VehiclePropValue propValue);
/**
* Set property value is usually asynchronous operation. Thus even if
* client received StatusCode::OK from the IVehicle::set(...) this
* doesn't guarantee that the value was successfully propagated to the
* vehicle network. If such rare event occurs this method must be called.
*
* @param errorCode - any value from StatusCode enum.
* @param property - a property where error has happened.
* @param areaId - bitmask that specifies in which areas the problem has
* occurred, must be 0 for global properties
* 设置属性通常是异步操作，客户端调用 IVehicle#set 函数到接收到 StatusCode::OK 的返回值，也不能保证此属性成功传播到车辆网络，如果发生这种低概率的事件，则回调此方法。
* @ errorCode：StatusCode 枚举中的任何值。
* @ property：发生错误的属性。
* @ areaId：指定问题发生在哪个区域的位掩码，对于全局属性必须为 0。
*/
oneway onPropertySetError(StatusCode errorCode,
int32_t propId,
int32_t areaId);
};
2.3.3 types.hal
types.hal 中定义了 VehicleHal 的属性、结构等数据。
2.3.3.1 车辆属性 VehiclePropertyType
下面列举 types.hal 中定义的 VehiclePropertyType 属性：
package android.hardware.automotive.vehicle@2.0;
/**
* Enumerates supported data type for VehicleProperty.
* 枚举 VehicleProperty 支持的数据类型。
* Used to create property ID in VehicleProperty enum.
* 用于在 VehicleProperty enum 中创建属性 ID。
*/
enum VehiclePropertyType : int32_t { // VehicleProperty 的类型是 string、bool、还是 int32 等等
STRING = 0x00100000,
BOOLEAN = 0x00200000,
INT32 = 0x00400000,
INT32_VEC = 0x00410000,
INT64 = 0x00500000,
INT64_VEC = 0x00510000,
FLOAT = 0x00600000,
FLOAT_VEC = 0x00610000,
BYTES = 0x00700000,
/**
* Any combination of scalar or vector types. The exact format must be
* provided in the description of the property.
*/
MIXED = 0x00e00000, // 这两个主要就是 VehicleProperty 用来进行或运算的。
MASK = 0x00ff0000
};
2.3.3.2 车辆区域属性 VehicleArea
下面是 types.hal 中定义的车辆区域属性：
/**
* Vehicle Areas
* Used to construct property IDs in the VehicleProperty enum.
* 用于在VehicleProperty enum中构造属性id。
*
* Some properties may be associated with particular vehicle areas. For
* example, VehicleProperty:DOOR_LOCK property must be associated with
* particular door, thus this property must be marked with
* VehicleArea:DOOR flag.
* 某些属性可能与特定车辆区域相关。例如，VehicleProperty:DOOR_LOCK 属性必须与特定的门相关联，因此该属性必须标记为 VehicleArea: door 标志。
*
* Other properties may not be associated with particular vehicle area,
* these kind of properties must have VehicleArea:GLOBAL flag.
* 其他属性可能不与特定的车辆区域相关联，这些属性必须具有VehicleArea:GLOBAL标志。
*
* [Definition] Area: An area represents a unique element of an AreaType.
* For instance, if AreaType is WINDOW, then an area may be FRONT_WINDSHIELD.
*
* [Definition] AreaID: An AreaID is a combination of one or more areas,
* and is represented using a bitmask of Area enums. Different AreaTypes may
* not be mixed in a single AreaID. For instance, a window area cannot be
* combined with a seat area in an AreaID.
*
* Rules for mapping a zoned property to AreaIDs:
* - A property must be mapped to an array of AreaIDs that are impacted when
* the property value changes.
* - Each element in the array must represent an AreaID, in which, the
* property value can only be changed together in all the areas within
* an AreaID and never independently. That is, when the property value
* changes in one of the areas in an AreaID in the array, then it must
* automatically change in all other areas in the AreaID.
* - The property value must be independently controllable in any two
* different AreaIDs in the array.
* - An area must only appear once in the array of AreaIDs. That is, an
* area must only be part of a single AreaID in the array.
*
* [Definition] Global Property: A property that applies to the entire car
* and is not associated with a specific area. For example, FUEL_LEVEL,
* HVAC_STEERING_WHEEL_HEAT.
*
* Rules for mapping a global property to AreaIDs:
* - A global property must not be mapped to AreaIDs.
*/
enum VehicleArea : int32_t {
GLOBAL = 0x01000000, // 全局区域
/** WINDOW maps to enum VehicleAreaWindow */
WINDOW = 0x03000000, // 窗户区域
/** MIRROR maps to enum VehicleAreaMirror */
MIRROR = 0x04000000, // 反光镜区域
/** SEAT maps to enum VehicleAreaSeat */
SEAT = 0x05000000, // 座椅区域
/** DOOR maps to enum VehicleAreaDoor */
DOOR = 0x06000000, // 车门区域
/** WHEEL maps to enum VehicleAreaWheel */
WHEEL = 0x07000000, // 车轮区域
YFVehicleAreaTire = 0x08000000,
MASK = 0x0f000000,
};
2.3.3.3 车辆属性分组类型 VehiclePropertyGroup
下面是 types.hal 中定义的车辆属性分组类型：
/**
* Enumerates property groups.
* 车辆属性分组枚举
*
* Used to create property ID in VehicleProperty enum.
* 用于在VehicleProperty enum中创建属性ID。
*/
enum VehiclePropertyGroup : int32_t { // AndroidO 之后的 treble，用于区分 android 原生的 property 和厂商的 property。
/**
* Properties declared in AOSP must use this flag.
* AOSP 原生的属性标志
*/
SYSTEM = 0x10000000,
/**
* Properties declared by vendors must use this flag.
* 厂商自定义的属性标志
*/
VENDOR = 0x20000000,
MASK = 0xf0000000,
};
2.3.3.4 车辆属性 VehicleProperty
下面是 types.hal 中定义的车辆属性
/**
* Declares all vehicle properties. VehicleProperty has a bitwise structure.
* Each property must have:
* - a unique id from range 0x0100 - 0xffff
* - associated data type using VehiclePropertyType
* - property group (VehiclePropertyGroup)
* - vehicle area (VehicleArea)
*
* Vendors are allowed to extend this enum with their own properties. In this
* case they must use VehiclePropertyGroup:VENDOR flag when property is
* declared.
*
* When a property's status field is not set to AVAILABLE:
* - IVehicle#set may return StatusCode::NOT_AVAILABLE.
* - IVehicle#get is not guaranteed to work.
*
* Properties set to values out of range must be ignored and no action taken
* in response to such ill formed requests.
*/
enum VehicleProperty : int32_t {
/** Undefined property. */
INVALID = 0x00000000,
/**
* VIN of vehicle
* 车辆 VIN 码
*
* @change_mode VehiclePropertyChangeMode:STATIC
* @access VehiclePropertyAccess:READ
*/
INFO_VIN = (
0x0100
| VehiclePropertyGroup:SYSTEM // 原生属性
| VehiclePropertyType:STRING // 属性值是 String 类型
| VehicleArea:GLOBAL), // 全局属性
/**
* Model of vehicle
* 车辆型号
*
* @change_mode VehiclePropertyChangeMode:STATIC
* @access VehiclePropertyAccess:READ
*/
INFO_MODEL = (
0x0102
| VehiclePropertyGroup:SYSTEM // 原生属性
| VehiclePropertyType:STRING // 属性值是 String 类型
| VehicleArea:GLOBAL), // 全局属性
...
};
2.3.3.5 车辆座位占用状态 VehicleSeatOccupancyState
下面是 types.hal 中定义的车辆座位占用状态值
/**
* Used by seat occupancy to enumerate the current occupancy state of the seat.
* 由座位占用使用，以枚举座位的当前占用状态
*/
enum VehicleSeatOccupancyState : int32_t {
UNKNOWN = 0,
VACANT = 1, // 空闲
OCCUPIED = 2 // 占用
};
2.3.3.6 灯光状态属性 VehicleLightState
下面是 types.hal 中定义的灯光状态属性
/**
* Used by lights state properties to enumerate the current state of the lights.
* 由灯光状态属性使用，枚举灯光的当前状态。
* Most XXX_LIGHTS_STATE properties will only report ON and OFF states. Only
* the HEADLIGHTS_STATE property will report DAYTIME_RUNNING.
* 大多数 XXX_LIGHTS_STATE 属性将只报告 ON 和 OFF 状态。只有 headlight_state 属性会报告 DAYTIME_RUNNING。
*/
enum VehicleLightState : int32_t {
OFF = 0,
ON = 1,
DAYTIME_RUNNING = 2
};
2.3.3.7 车灯开关属性 VehicleLightSwitch
下面是 types.hal 中定义的车灯开关属性
/**
* Used by lights switch properties to enumerate user selected switch setting.
* 由灯开关属性使用，枚举用户选择的开关设置。
* XXX_LIGHTS_SWITCH properties report the switch settings that the user
* selects. The switch setting may be decoupled from the state reported if the
* user selects AUTOMATIC.
* XXX_LIGHTS_SWITCH 属性报告用户选择的开关设置。如果用户选择 AUTOMATIC，开关设置可能与报告的状态分离。
*/
enum VehicleLightSwitch : int32_t {
OFF = 0,
ON = 1,
/**
* Daytime running lights mode. Most cars automatically use DRL but some
* cars allow the user to activate them manually.
* 日间行车灯模式。大多数汽车自动使用DRL，但有些汽车允许用户手动激活它们。
*/
DAYTIME_RUNNING = 2,
/**
* Allows the vehicle ECU to set the lights automatically
* 允许车辆ECU自动设置灯光
*/
AUTOMATIC = 0x100,
};
2.3.3.8 车辆充电连接线类型 EvConnectorType
下面是 types.hal 中定义的车辆充电连接线类型属性
/**
* Used by INFO_EV_CONNECTOR_TYPE to enumerate the type of connectors
* available to charge the vehicle.
* 由 INFO_EV_CONNECTOR_TYPE 使用，枚举可用于给车辆充电的连接器类型。
*/
enum EvConnectorType : int32_t {
/**
* Default type if the vehicle does not know or report the EV connector
* type.
* 如果车辆不知道或不报告EV连接器类型，则默认类型
*/
UNKNOWN = 0,
IEC_TYPE_1_AC = 1, // aka Yazaki
IEC_TYPE_2_AC = 2, // aka Mennekes
IEC_TYPE_3_AC = 3, // aka Scame
IEC_TYPE_4_DC = 4, // aka CHAdeMO
IEC_TYPE_1_CCS_DC = 5, // aka Combo 1
IEC_TYPE_2_CCS_DC = 6, // aka Combo 2
TESLA_ROADSTER = 7,
TESLA_HPWC = 8,
TESLA_SUPERCHARGER = 9,
GBT_AC = 10,
GBT_DC = 11,
/**
* Connector type to use when no other types apply. Before using this
* value, work with Google to see if the EvConnectorType enum can be
* extended with an appropriate value.
*/
OTHER = 101,
};
2.3.3.9 端口位置属性 PortLocationType
下面是 types.hal 中定义的用于枚举燃油门或燃油口位置属性。
/**
* Used by INFO_FUEL_DOOR_LOCATION/INFO_CHARGE_PORT_LOCATION to enumerate fuel door or
* ev port location.
* 用于描述 INFO_FUEL_DOOR_LOCATION 和 INFO_CHARGE_PORT_LOCATION 信号的燃油门或燃油口位置。
*/
enum PortLocationType : int32_t {
/**
* Default type if the vehicle does not know or report the Fuel door
* and ev port location.
*/
UNKNOWN = 0,
FRONT_LEFT = 1,
FRONT_RIGHT = 2,
REAR_RIGHT = 3,
REAR_LEFT = 4,
FRONT = 5,
REAR = 6,
};
2.3.3.10 风扇方向属性 VehicleHvacFanDirection
下面是 types.hal 中定义的风扇方向属性。
/**
* Bit flags for fan direction
* 风扇方向的位标志
*/
enum VehicleHvacFanDirection : int32_t {
FACE = 0x1,
FLOOR = 0x2,
DEFROST = 0x4,
};
2.3.3.11 车辆油量属性 VehicleOilLevel
下面是 types.hal 中定义的车辆油量属性。
enum VehicleOilLevel : int32_t {
/**
* Oil level values
*/
CRITICALLY_LOW = 0,
LOW = 1,
NORMAL = 2,
HIGH = 3,
ERROR = 4,
};
2.3.3.12 车辆输入事件属性 VehicleHwKeyInputAction
下面是 types.hal 中定义的车辆输入事件属性。
enum VehicleHwKeyInputAction : int32_t {
/** Key down */
ACTION_DOWN = 1, // 输入事件按下
/** Key up */
ACTION_UP = 0, // 输入事件抬起
};
2.3.3.13 车辆属性修改模式 VehiclepropertyChangeMode
下面是 types.hal 中定义的属性是否可以改变的配置。
/**
* This describes how value of property can change.
* 描述属性是否可以改变
*/
enum VehiclePropertyChangeMode : int32_t {
/**
* Property of this type must never be changed. Subscription is not supported
* for these properties.
* STATIC 表示属性不可修改
*/
STATIC = 0x00,
/**
* Properties of this type must report when there is a change.
* IVehicle#get call must return the current value.
* Set operation for this property is assumed to be asynchronous. When the
* property is read (using IVehicle#get) after IVehicle#set, it may still
* return old value until underlying H/W backing this property has actually
* changed the state. Once state is changed, the property must dispatch
* changed value as event.
* ON_CHANGE 表示属性必须在改变时报告
*/
ON_CHANGE = 0x01,
/**
* Properties of this type change continuously and require a fixed rate of
* sampling to retrieve the data. Implementers may choose to send extra
* notifications on significant value changes.
* CONTINUOUS 属性在不断变化，需要固定的速率来检索数据
*/
CONTINUOUS = 0x02,
};
2.3.3.14 车辆属性访问 VehiclePropertyAccess
下面是 types.hal 中定义的车辆属性访问配置。
/**
* Property config defines the capabilities of it. User of the API
* must first get the property config to understand the output from get()
* commands and also to ensure that set() or events commands are in sync with
* the expected output.
* 属性定义功能访问模式。
*/
enum VehiclePropertyAccess : int32_t {
NONE = 0x00,
READ = 0x01, // 只读
WRITE = 0x02, // 只写
READ_WRITE = 0x03, // 读写
};
2.3.3.15 车辆属性状态 VehiclePropertyStatus
下面是 types.hal 中定义的车辆属性状态。
/**
* Property status is a dynamic value that may change based on the vehicle state.
* 属性状态是一个动态值，可能会根据车辆状态而改变。
*/
enum VehiclePropertyStatus : int32_t {
/** Property is available and behaving normally */
AVAILABLE = 0x00, // 属性可用且运行正常
/**
* A property in this state is not available for reading and writing. This
* is a transient state that depends on the availability of the underlying
* implementation (e.g. hardware or driver). It MUST NOT be used to
* represent features that this vehicle is always incapable of. A get() of
* a property in this state MAY return an undefined value, but MUST
* correctly describe its status as UNAVAILABLE A set() of a property in
* this state MAY return NOT_AVAILABLE. The HAL implementation MUST ignore
* the value of the status field when writing a property value coming from
* Android.
*/
UNAVAILABLE = 0x01, // 处于此状态的属性不可用于读写。这是一种瞬态，依赖于底层实现的可用性(例如硬件或驱动程序)。
/** There is an error with this property. */
ERROR = 0x02,
};
2.3.3.16 汽车齿轮属性 VehicleGear
下面是 types.hal 中定义的汽车齿轮属性。
/**
* Various gears which can be selected by user and chosen in system.
* 各种齿轮可由用户选择，并在系统中选择。
*/
enum VehicleGear : int32_t {
GEAR_NEUTRAL = 0x0001,
GEAR_REVERSE = 0x0002,
GEAR_PARK = 0x0004,
GEAR_DRIVE = 0x0008,
GEAR_1 = 0x0010,
GEAR_2 = 0x0020,
GEAR_3 = 0x0040,
GEAR_4 = 0x0080,
GEAR_5 = 0x0100,
GEAR_6 = 0x0200,
GEAR_7 = 0x0400,
GEAR_8 = 0x0800,
GEAR_9 = 0x1000,
};
2.3.3.17 汽车座椅区域属性 VehicleAreaSeat
下面是 types.hal 中定义的汽车座椅区域属性。
/**
* Various Seats in the car.
* 汽车里的各种座位。
*/
enum VehicleAreaSeat : int32_t {
ROW_1_LEFT = 0x0001,
ROW_0_CENTER = 0x0002,
ROW_1_RIGHT = 0x0004,
ROW_2_LEFT = 0x0010,
ROW_2_CENTER = 0x0020,
ROW_2_RIGHT = 0x0040,
ROW_3_LEFT = 0x0100,
ROW_3_CENTER = 0x0200,
ROW_3_RIGHT = 0x0400
};
2.3.3.18 汽车玻璃区域属性 VehicleAreaWindow
下面是 types.hal 中定义的汽车玻璃区域属性。
/**
* Various windshields/windows in the car.
* 汽车的各种挡风玻璃/窗户。
*/
enum VehicleAreaWindow : int32_t {
FRONT_WINDSHIELD = 0x00000001, // 前挡风玻璃
REAR_WINDSHIELD = 0x00000002, // 后挡风玻璃
ROW_1_LEFT = 0x00000010,
ROW_1_RIGHT = 0x00000040,
ROW_2_LEFT = 0x00000100,
ROW_2_RIGHT = 0x00000400,
ROW_3_LEFT = 0x00001000,
ROW_3_RIGHT = 0x00004000,
ROOF_TOP_1 = 0x00010000,
ROOF_TOP_2 = 0x00020000,
};
2.3.3.19 车辆门区域属性 VehicleAreaDoor
下面是 types.hal 中定义的车辆门区域属性。
enum VehicleAreaDoor : int32_t {
ROW_1_LEFT = 0x00000001,
ROW_1_RIGHT = 0x00000004,
ROW_2_LEFT = 0x00000010,
ROW_2_RIGHT = 0x00000040,
ROW_3_LEFT = 0x00000100,
ROW_3_RIGHT = 0x00000400,
HOOD = 0x10000000,
REAR = 0x20000000,
};
2.3.3.20 车辆镜子区域属性 VehicleAreaMirror
下面是 types.hal 中定义的车辆镜子区域属性。
enum VehicleAreaMirror : int32_t {
DRIVER_LEFT = 0x00000001,
DRIVER_RIGHT = 0x00000002,
DRIVER_CENTER = 0x00000004,
};
2.3.3.21 车辆转向灯属性 VehicleTurnSignal
下面是 types.hal 中定义的车辆转向灯属性。
enum VehicleTurnSignal : int32_t {
NONE = 0x00,
RIGHT = 0x01,
LEFT = 0x02,
};
2.3.3.22 车辆区域配置结构体 VehicleAreaConfig
下面是 types.hal 中定义的车辆区域配置结构体。
struct VehicleAreaConfig {
/**
* Area id is ignored for VehiclePropertyGroup:GLOBAL properties.
* 对于全局属性，忽略 Area 区域 id。
*/
int32_t areaId;
/**
* If the property has @data_enum, leave the range to zero.
*
* Range will be ignored in the following cases:
* - The VehiclePropertyType is not INT32, INT64 or FLOAT.
* - Both of min value and max value are zero.
*/
int32_t minInt32Value;
int32_t maxInt32Value;
int64_t minInt64Value;
int64_t maxInt64Value;
float minFloatValue;
float maxFloatValue;
};
2.3.3.23 车辆属性配置 VehiclePropConfig
下面是 types.hal 中定义的车辆属性配置。
struct VehiclePropConfig { // Vehicle Property 的配置
/** Property identifier */
int32_t prop; // property 标识符
/**
* Defines if the property is read or write or both.
*/
VehiclePropertyAccess access; // 定义属性是读还是写，还是两者兼而有之
/**
* Defines the change mode of the property.
*/
VehiclePropertyChangeMode changeMode; // 定义属性的更改模式
/**
* Contains per-area configuration.
*/
vec<VehicleAreaConfig> areaConfigs; // 包含每个区域的配置
/** Contains additional configuration parameters */
vec<int32_t> configArray; // 包含其他配置参数
/**
* Some properties may require additional information passed over this
* string. Most properties do not need to set this.
*/
string configString; // 某些属性可能需要通过该字符串传递额外的信息
/**
* Min sample rate in Hz.
* Must be defined for VehiclePropertyChangeMode::CONTINUOUS
*/
float minSampleRate; // 最小采样率(Hz)
/**
* Must be defined for VehiclePropertyChangeMode::CONTINUOUS
* Max sample rate in Hz.
*/
float maxSampleRate; // 最大采样率(Hz)
};
2.3.3.24 车辆属性值 VehiclePropValue
下面是 types.hal 中定义的车辆属性值。
/**
* Encapsulates the property name and the associated value. It
* is used across various API calls to set values, get values or to register for
* events.
* 封装属性名和关联值。它在各种 API 调用中用于设置值、获取值或注册事件。
*/
struct VehiclePropValue {
/** Time is elapsed nanoseconds since boot */
int64_t timestamp; // 从 boot 开始的时间
/**
* Area type(s) for non-global property it must be one of the value from
* VehicleArea* enums or 0 for global properties.
* 对于非全局属性，区域类型必须是VehicleArea*枚举中的值之一；对于全局属性必须是0。
*/
int32_t areaId;
/** Property identifier */
int32_t prop; // 属性标识符
/** Status of the property */
VehiclePropertyStatus status; // 属性状态
/**
* Contains value for a single property. Depending on property data type of
* this property (VehiclePropetyType) one field of this structure must be filled in.
* 包含单个属性的值。根据该属性的属性数据类型(vehiclepetytype)，必须填充该结构的一个字段。
*/
struct RawValue {
/**
* This is used for properties of types VehiclePropertyType#INT
* and VehiclePropertyType#INT_VEC
*/
vec<int32_t> int32Values;
/**
* This is used for properties of types VehiclePropertyType#FLOAT
* and VehiclePropertyType#FLOAT_VEC
*/
vec<float> floatValues;
/** This is used for properties of type VehiclePropertyType#INT64 */
vec<int64_t> int64Values;
/** This is used for properties of type VehiclePropertyType#BYTES */
vec<uint8_t> bytes;
/** This is used for properties of type VehiclePropertyType#STRING */
string stringValue;
};
RawValue value;
};
2.4 启动流程
2.4.1 VehicleHal 类图
下面是 VehicleHal 的类图
2.4.2 VehicleHal 启动序列图
下面是 VehicleHal 启动序列图
2.4.3 VehicleHal 启动流程
2.4.3.1 VehicleService.cpp
VehicleHal 的入口文件是 VehicleService.cpp。路径为：android/hardware/interfaces/automotive/vehicle/2.0/default。下面是 VehicleService.cpp 的内容：
#define LOG_TAG "automotive.vehicle@2.0-service"
#include <android/log.h>
#include <hidl/HidlTransportSupport.h>
#include <iostream>
#include <vhal_v2_0/VehicleHalManager.h>
#include <vhal_v2_0/EmulatedVehicleHal.h>
using namespace android;
using namespace android::hardware;
using namespace android::hardware::automotive::vehicle::V2_0;
int main(int /* argc */, char* /* argv */ []) {
// 创建 VehiclePropertyStore 对象
auto store = std::make_unique<VehiclePropertyStore>();
// 创建 EmulatedVehicleHal 对象
auto hal = std::make_unique<impl::EmulatedVehicleHal>(store.get());
// 创建 VehicleEmulator 对象
auto emulator = std::make_unique<impl::VehicleEmulator>(hal.get());
// 创建 VehicleHalManager 对象
auto service = std::make_unique<VehicleHalManager>(hal.get());
configureRpcThreadpool(4, true /* callerWillJoin */);
// 注册 VehicleService 服务
ALOGI("Registering as service...");
status_t status = service->registerAsService();
if (status != OK) {
ALOGE("Unable to register vehicle service (%d)", status);
return 1;
}
ALOGI("Ready");
joinRpcThreadpool();
return 1;
}
从 VehicleService.cpp 中可以发现，主要初始化了 Vehicle 相关服务类，并注册 Vehicle 服务。下面可以来简单跟踪下各类的功能。
2.4.3.2 VehiclePropertyStore.cpp
VehiclePropertyStore 类是用于封装与存储和访问配置、存储和修改车辆属性值相关的工作。内部主要维护一个 PropertyMap mPropertyValues，PropertyMap = std::map<RecordId, VehiclePropValue>；用于通过 RecordId 保存对应的 VehiclePropValue 值。
VehiclePropValue.h ：
android/hardware/interfaces/automotive/vehicle/2.0/default/common/include/vhal_v2_0/VehiclePropertyStore.h
VehiclePropertyStore.cpp ：
android/hardware/interfaces/automotive/vehicle/2.0/default/common/src/VehiclePropertyStore.cpp
车辆属性在 VehiclePropertyStore 是存储在有序的 Map 集合中，这样可以更加方便的获取属性的值。VehiclePropertyStore 的使用是线程安全的，方法间使用同步阻塞保证线程安全。
下面是 VehiclePropertyStore.h 头文件的内容：
class VehiclePropertyStore {
public:
/* Function that used to calculate unique token for given VehiclePropValue */
using TokenFunction = std::function<int64_t(const VehiclePropValue& value)>;
private:
// 定义 RecordConfig 结构体
struct RecordConfig {
VehiclePropConfig propConfig;
TokenFunction tokenFunction;
};
// 定义 RecordId 结构体
struct RecordId {
int32_t prop; // propid
int32_t area; // areaid
int64_t token;
bool operator==(const RecordId& other) const;
bool operator<(const RecordId& other) const;
};
// 定义 RecordId 和 vehiclePropValue 对应的 Map 集合
using PropertyMap = std::map<RecordId, VehiclePropValue>;
using PropertyMapRange = std::pair<PropertyMap::const_iterator, PropertyMap::const_iterator>;
public:
// 注册 Property 函数
void registerProperty(const VehiclePropConfig& config, TokenFunction tokenFunc = nullptr);
/* Stores provided value. Returns true if value was written returns false if config for
* example wasn't registered. */
// 写入 VehiclePropValue 值
bool writeValue(const VehiclePropValue& propValue, bool updateStatus);
// 移除 VehiclePropValue 值
void removeValue(const VehiclePropValue& propValue);
// 通过 propId 移除 VehiclePropValue 值
void removeValuesForProperty(int32_t propId);
// 获取所有的 VehiclePropValue 值
std::vector<VehiclePropValue> readAllValues() const;
std::vector<VehiclePropValue> readValuesForProperty(int32_t propId) const;
std::unique_ptr<VehiclePropValue> readValueOrNull(const VehiclePropValue& request) const;
std::unique_ptr<VehiclePropValue> readValueOrNull(int32_t prop, int32_t area = 0,
int64_t token = 0) const;
// 获取所有的 VehiclePropConfig 值
std::vector<VehiclePropConfig> getAllConfigs() const;
// 根据 propId 获取 VehiclePropConfig 值
const VehiclePropConfig* getConfigOrNull(int32_t propId) const;
const VehiclePropConfig* getConfigOrDie(int32_t propId) const;
private:
RecordId getRecordIdLocked(const VehiclePropValue& valuePrototype) const;
const VehiclePropValue* getValueOrNullLocked(const RecordId& recId) const;
PropertyMapRange findRangeLocked(int32_t propId) const;
private:
using MuxGuard = std::lock_guard<std::mutex>;
mutable std::mutex mLock;
std::unordered_map<int32_t /* VehicleProperty */, RecordConfig> mConfigs;
PropertyMap mPropertyValues; // Sorted map of RecordId : VehiclePropValue.
};
2.4.3.3 EmulatedVehicleHal
EmulatedVehicleHal 的文件路径如下：
EmulatedVehicleHal.h 路径为：
android/hardware/interfaces/automotive/vehicle/2.0/default/impl/vhal_v2_0/EmulatedVehicleHal.h
EmulatedVehicleHal.cpp 路径为：
android/hardware/interfaces/automotive/vehicle/2.0/defaultandroid/hardware/interfaces/automotive/vehicle/2.0/default/impl/vhal_v2_0/EmulatedVehicleHal.cpp
EmulatedVehicleHal 可以理解为 VehicleHal 功能的真正实施类，EmulatedVehicleHal 实现了 EmulatedVehicleHalIface 和 VehicleHal 的功能。上层的 Binder 在 Hal 层的流转后，最终是通过 EmulatedVehicleHal 去处理的。下面是 EmulatedVehicleHal 头文件的内容：
class EmulatedVehicleHal : public EmulatedVehicleHalIface { // EmulatedVehicleHalIface 继承了 VehicleHal
public:
EmulatedVehicleHal(VehiclePropertyStore* propStore);
~EmulatedVehicleHal() = default;
// Methods from VehicleHal
// 实现了 VehicleHal 接口功能，上层的 Binder 调用会调用到这里
void onCreate() override;
std::vector<VehiclePropConfig> listProperties() override;
VehiclePropValuePtr get(const VehiclePropValue& requestedPropValue,
StatusCode* outStatus) override;
StatusCode set(const VehiclePropValue& propValue) override;
StatusCode subscribe(int32_t property, float sampleRate) override;
StatusCode unsubscribe(int32_t property) override;
// Methods from EmulatedVehicleHalIface
// 实现了 EmulatedVehicleHalIface 接口功能
bool setPropertyFromVehicle(const VehiclePropValue& propValue) override;
std::vector<VehiclePropValue> getAllProperties() const override;
private:
constexpr std::chrono::nanoseconds hertzToNanoseconds(float hz) const {
return std::chrono::nanoseconds(static_cast<int64_t>(1000000000L / hz));
}
StatusCode handleGenerateFakeDataRequest(const VehiclePropValue& request);
void onFakeValueGenerated(const VehiclePropValue& value);
VehiclePropValuePtr createApPowerStateReq(VehicleApPowerStateReq req, int32_t param);
VehiclePropValuePtr createHwInputKeyProp(VehicleHwKeyInputAction action, int32_t keyCode,
int32_t targetDisplay);
void onContinuousPropertyTimer(const std::vector<int32_t>& properties);
bool isContinuousProperty(int32_t propId) const;
void initStaticConfig();
void initObd2LiveFrame(const VehiclePropConfig& propConfig);
void initObd2FreezeFrame(const VehiclePropConfig& propConfig);
StatusCode fillObd2FreezeFrame(const VehiclePropValue& requestedPropValue,
VehiclePropValue* outValue);
StatusCode fillObd2DtcInfo(VehiclePropValue* outValue);
StatusCode clearObd2FreezeFrames(const VehiclePropValue& propValue);
/* Private members */
VehiclePropertyStore* mPropStore;
std::unordered_set<int32_t> mHvacPowerProps;
RecurrentTimer mRecurrentTimer;
GeneratorHub mGeneratorHub;
};
2.4.3.4 VehicleEmulator
VehicleEmulator 的文件路径如下：
VehicleEmulator.h 的文件路径为：android/hardware/interfaces/automotive/vehicle/2.0/default/impl/vhal_v2_0/VehicleEmulator.h
VehicleEmulator.cpp 的文件路径为：
android/hardware/interfaces/automotive/vehicle/2.0/default/impl/vhal_v2_0/VehicleEmulator.cpp
VehicleEmulator 的解释是通过 ADB 或 Pipe 从主机端提供控制接口来模拟车辆。
VehicleEmulator 可以理解为通过 SPI 通信与 MCU 芯片建立通信，连通车身 Can 网络来获取车辆的信号的处理类。厂商基于 VehicleEmulator 的功能搭建厂商自身的车身通信功能，例如通过 DBus 与 MCU 通信，获取来自 MCU 的车身数据；MCU 通过 Can 网络获取车身其他固件，例如空调、座椅等其他 ECU 件的数据。
下面是 VehicleEmulator.h 文件的内容：
class VehicleEmulator; // Forward declaration.
/** Extension of VehicleHal that used by VehicleEmulator. */
// 定义 EmulatedVehicleHalIface 类，扩展 VehicleHal 接口。
class EmulatedVehicleHalIface : public VehicleHal {
public:
virtual bool setPropertyFromVehicle(const VehiclePropValue& propValue) = 0;
virtual std::vector<VehiclePropValue> getAllProperties() const = 0;
void registerEmulator(VehicleEmulator* emulator) {
ALOGI("%s, emulator: %p", __func__, emulator);
std::lock_guard<std::mutex> g(mEmulatorLock);
mEmulator = emulator;
}
protected:
VehicleEmulator* getEmulatorOrDie() {
std::lock_guard<std::mutex> g(mEmulatorLock);
if (mEmulator == nullptr) abort();
return mEmulator;
}
private:
mutable std::mutex mEmulatorLock;
VehicleEmulator* mEmulator;
};
/**
* Emulates vehicle by providing controlling interface from host side either through ADB or Pipe.
*/
// 定义 VehicleEmulator 类，通过 socket、pipe 模拟车辆
class VehicleEmulator : public MessageProcessor {
public:
VehicleEmulator(EmulatedVehicleHalIface* hal);
virtual ~VehicleEmulator();
void doSetValueFromClient(const VehiclePropValue& propValue);
void processMessage(emulator::EmulatorMessage const& rxMsg,
emulator::EmulatorMessage& respMsg) override;
private:
friend class ConnectionThread;
using EmulatorMessage = emulator::EmulatorMessage;
void doGetConfig(EmulatorMessage const& rxMsg, EmulatorMessage& respMsg);
void doGetConfigAll(EmulatorMessage const& rxMsg, EmulatorMessage& respMsg);
void doGetProperty(EmulatorMessage const& rxMsg, EmulatorMessage& respMsg);
void doGetPropertyAll(EmulatorMessage const& rxMsg, EmulatorMessage& respMsg);
void doSetProperty(EmulatorMessage const& rxMsg, EmulatorMessage& respMsg);
void populateProtoVehicleConfig(emulator::VehiclePropConfig* protoCfg,
const VehiclePropConfig& cfg);
void populateProtoVehiclePropValue(emulator::VehiclePropValue* protoVal,
const VehiclePropValue* val);
private:
EmulatedVehicleHalIface* mHal;
std::unique_ptr<SocketComm> mSocketComm;
std::unique_ptr<PipeComm> mPipeComm;
};
2.4.3.5 VehicleHalManager
VehicleHalManager 的文件路径如下：
VehicleHalManager.h 文件路径为：android/hardware/interfaces/automotive/vehicle/2.0/default/common/include/vhal_v2_0/VehicleHalManager.h
VehicleHalManager.cpp 文件路径为：
android/hardware/interfaces/automotive/vehicle/2.0/default/common/src/VehicleHalManager.cpp
VehicleHalManager 类是 IVehicle HIDL 接口和厂商实现之间的一个代理。VehicleHalManager 直接继承了 IVehicle，上层调用 Hild 接口时，会最先调用到此类中，VehicleHalManager 在初始化时获取 VehicleHal 对象，厂商需要实现 VehicleHal 类以提供 VehicleHal 的功能。
下面是 VehicleHalManager.h 文件的内容：
/**
* This class is a thick proxy between IVehicle HIDL interface and vendor's implementation.
*
* It has some boilerplate code like batching and caching property values, checking permissions,
* etc. Vendors must implement VehicleHal class.
*/
// VehicleHalManager 继承 IVehicle 类，提供 Hidl 接口调用
class VehicleHalManager : public IVehicle {
public:
// 构造函数需要传入 VehicleHal 类对象，具体 Hidl 接口功能实现由 VehicleHal 提供
VehicleHalManager(VehicleHal* vehicleHal)
: mHal(vehicleHal),
mSubscriptionManager(std::bind(&VehicleHalManager::onAllClientsUnsubscribed,
this, std::placeholders::_1)) {
init();
}
virtual ~VehicleHalManager();
void init();
// ---------------------------------------------------------------------------------------------
// Methods derived from IVehicle 实现 Hidl 接口函数
Return<void> getAllPropConfigs(getAllPropConfigs_cb _hidl_cb) override;
Return<void> getPropConfigs(const hidl_vec<int32_t>& properties,
getPropConfigs_cb _hidl_cb) override;
Return<void> get(const VehiclePropValue& requestedPropValue,
get_cb _hidl_cb) override;
Return<StatusCode> set(const VehiclePropValue& value) override;
Return<StatusCode> subscribe(const sp<IVehicleCallback>& callback,
const hidl_vec<SubscribeOptions>& options) override;
Return<StatusCode> unsubscribe(const sp<IVehicleCallback>& callback,
int32_t propId) override;
Return<void> debugDump(debugDump_cb _hidl_cb = nullptr) override;
private:
using VehiclePropValuePtr = VehicleHal::VehiclePropValuePtr;
// Returns true if needs to call again shortly.
using RetriableAction = std::function<bool()>;
// ---------------------------------------------------------------------------------------------
// Events received from VehicleHal
void onHalEvent(VehiclePropValuePtr v);
void onHalPropertySetError(StatusCode errorCode, int32_t property,
int32_t areaId);
// ---------------------------------------------------------------------------------------------
// This method will be called from BatchingConsumer thread
void onBatchHalEvent(const std::vector<VehiclePropValuePtr >& values);
void handlePropertySetEvent(const VehiclePropValue& value);
const VehiclePropConfig* getPropConfigOrNull(int32_t prop) const;
bool checkWritePermission(const VehiclePropConfig &config) const;
bool checkReadPermission(const VehiclePropConfig &config) const;
void onAllClientsUnsubscribed(int32_t propertyId);
static bool isSubscribable(const VehiclePropConfig& config,
SubscribeFlags flags);
static bool isSampleRateFixed(VehiclePropertyChangeMode mode);
static float checkSampleRate(const VehiclePropConfig& config,
float sampleRate);
static ClientId getClientId(const sp<IVehicleCallback>& callback);
private:
VehicleHal* mHal; // 保存 VehicleHal 对象
std::unique_ptr<VehiclePropConfigIndex> mConfigIndex;
SubscriptionManager mSubscriptionManager;
hidl_vec<VehiclePropValue> mHidlVecOfVehiclePropValuePool;
ConcurrentQueue<VehiclePropValuePtr> mEventQueue;
BatchingConsumer<VehiclePropValuePtr> mBatchingConsumer;
VehiclePropValuePool mValueObjectPool;
};
3、总结
本篇主要描述了 Android 原生的 Automotive 框架中 VehicleHal 的逻辑。简单来说，VehicleHal 层主要是完成了对上层 Hidl 接口功能的实现，具体实现依赖厂商的逻辑，从框架上是封装了厂商的 VechielHal 实现，提供车辆网络信号的设置和获取功能。文章来源：https://www.toymoban.com/news/detail-849772.html
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