Android Qcom Sensor架构学习

Android Sensor Brief Flow

Android Sensor Specific Flow

ADSP SSC

ADSP.VT.5.4.1/adsp_proc/ssc_api/pb/
ADSP.VT.5.4.1/adsp_proc/ssc/sensors
ADSP.VT.5.4.1/adsp_proc/ssc/frameworks

ADSP Framework初始化的时候首先通过load image并初始化的静态加载方式register_static_sensors
ssc_static_lib_builder.py 会编译出静态加载的sensor列表 framework/build/sensor_img/…/sns_static_sensors.c
sensor的入口是register_function 定义在具体sensor的目录下的scons中 ssc/sensor/xxx/build/xxx.scons island_mode 支持低功耗

if 'USES_SSC_STATIC_LIB_BUILDER' in env:                 
  env.AddSSCSU(inspect.getfile(inspect.currentframe()),
               register_func_name = 

如果是动态加载的话，则是ssc/framework/dl/src/sns_dynamic_sensors.c，没具体研究

registry用于存放sensor信息的，放置在perisist分区，可通过registry sensor获取
通过/vendor/etc/sensors/config/<sensor_name><hardware_id>.json生成

mnt/vendor/persist/sensors/registry/
registry
sensor_list.txt
sensors_settings

在sensor_api::notify_event的过程中一般都会去处理registry,physical sensor包含很多硬件配置

if(SNS_REGISTRY_MSGID_SNS_REGISTRY_READ_EVENT == event->message_id)
  {
    
    
    sns_registry_read_event read_event = sns_registry_read_event_init_default;
    pb_buffer_arg group_name = {
    
    0,0};
    read_event.name.arg = &group_name;
    read_event.name.funcs.decode = pb_decode_string_cb;
   
    if(!pb_decode(&stream, sns_registry_read_event_fields, &read_event))
    {
    
    
      SNS_PRINTF(ERROR, this, "Error decoding registry event");
    }else
    {
    
    
        ...
        sns_registry_phy_sensor_pf_cfg phy_sensor_pf_cfg;
        memset(&phy_sensor_pf_cfg, 0, sizeof(phy_sensor_pf_cfg));
        sns_registry_decode_arg arg = {
    
    
          .item_group_name = &group_name,
          .parse_info_len = 1,
          .parse_info[0] = {
    
    
              .group_name = "config",
              .parse_func = sns_registry_parse_phy_sensor_pf_cfg,
              .parsed_buffer = &phy_sensor_pf_cfg
          }
        };

        read_event.data.items.funcs.decode = &sns_registry_item_decode_cb;
        read_event.data.items.arg = &arg;

        rv = pb_decode(&stream, sns_registry_read_event_fields, &read_event);
     ...
}

json中具体的配置，与解析后的应用后续再研究

sns_sensor::init -> publish_attibutes (physical sensor -> platform define name)
ltrx1303_publish_attributes -> "ambient_light"
icm4x6xx_accel_publish_attributes -> "accel"
sns_publish_attribute(this, SNS_STD_SENSOR_ATTRID_TYPE, &value, 1, false);

HAL SSC

https://source.android.google.cn/devices/sensors/sensors-multihal?skip_cache=true&hl=zh-cn

/hardware/interfaces/sensors/common/default/2.X/multihal/HalProxy.cpp
/vendor/qcom/proprietary/sensors-see/ssc/sns_std_sensor.proto -> sns_std_sensor.pb.h 
/vendor/qcom/proprietary/sensors-see/sensors-hal-2.0/framework/
/vendor/qcom/proprietary/sensors-see/sensors-hal-2.0/sensors/
vendor/qcom/proprietary/sensors-see/registry/config

SENSOR_MODULE_INIT初始化会注册两个unordered_map: callbacks and datatypes

sensor_factory::register_sensor  sensorType define in sensors_qti.h    
sensor_factory::request_datatype dataType   "accel" 

get_available_sensors(callbacks)
     push_back(make_unique<sensor>suid, SENSOR_WAKEUP))    //construct sensor 
     push_back(make_unique<sensor> suid, SENSOR_NO_WAKEUP)) //construct sensor
         set_type                  //QTI_SENSOR_TYPE
         set_string_type           //QTI_SENSOR_STRING_TYPE
         set_nowk_msgid            //SNS_STD_SENSOR_MSGID_SNS_STD_SENSOR_PHYSICAL_CONFIG_EVENT
         set_sensor_typename       //"Accelerometer" "SAR Sensor" 

无论时HAL与ADSP通信，还是ADSP内各sensor的通信，必须通过send_request, 通信的过程必须遵从protocol-buffers
其中最重要的两点需要suid和msg_id，suid时指定sensor(platform sensor:suid sensor，physical sensor:accel，virtual sensor:amd)

sensors_hal::activate  ssc_sensor::activate 
suid_lookup lookup
    const sensor_uid LOOKUP_SUID = {
    
                              //与suid sensor通信
        12370169555311111083ull,
        12370169555311111083ull
    };                 
pb_req_msg.set_msg_id(SNS_SUID_MSGID_SNS_SUID_REQ);           //请求具体sensor的suid 
            
lookup.request_suid                                           //通过stringtype获取具体sensor的suid        
send_sensor_config_request
    create_sensor_config_request()
       pb_req_msg.mutable_suid()->set_suid_high(_suid.high);  //request通信携带具体sensor的suid
       pb_req_msg.mutable_suid()->set_suid_low(_suid.low);
       _ssc_conn->send_request 
            if (stream_type == SNS_STD_SENSOR_STREAM_TYPE_STREAMING)  //attributes中的SNS_STD_SENSOR_ATTRID_STREAM_TYPE
                 pb_req_msg.set_msg_id(SNS_STD_SENSOR_MSGID_SNS_STD_SENSOR_CONFIG);//
            else
                 pb_req_msg.set_msg_id(SNS_STD_SENSOR_MSGID_SNS_STD_ON_CHANGE_CONFIG)   

APP and Framework

/frameworks/base/core/java/android/hardware/SensorManager.java
/frameworks/base/core/java/android/hardware/SystemSensorManager.java

Typical Sensor Type
* Sensor.TYPE_LIGHT：光传感器
* Sensor.TYPE_GRAVITY：重力传感器
* Sensor.TYPE_PRESSURE：压力传感器
* Sensor.TYPE_ALL: 所有支持的传感器
* Sensor.TYPE_ORIENTATION：方向传感器
* Sensor.TYPE_GYROSCOPE：陀螺仪传感器
* Sensor.TYPE_MAGNETIC_FIELD：磁场传感器
* Sensor.TYPE_AMBIENT_TEMPERATURE：温度传感器
* Sensor.TYPE_LINEAR_ACCELERATION：线性加速度传感器

如果是非典型的sensor类型，或者是客制化的，则需要从所有传感器类型中通过getStringType进行过滤,
注册并激活所需要的sensor,创建SensorEventQueue用于数据分发调用回调 onAccuracyChanged onSensorChanged
在注册时需要注意isWakeUpSensor判断，因为在HAL初始化的时候我们知道同一类型sensor又会细分为两种类型
SENSOR_WAKEUP和SENSOR_NO_WAKEUP，SENSOR_WAKEUP在系统休眠时也可以上报事件，可以用作抬腕唤醒等功能