Table of Contents
sensor的data event事件是怎麼發送到event loop的
CHRE代碼組成
chre_api是向nanoapp提供的接口，core、platform是實現chre的核心代碼
EventLoopManager
EventLoopManager包含管理sensor等各種manager，通過EventLoopManger訪問其他資源
//! Provide an alias to the EventLoopManager singleton.
typedef Singleton<EventLoopManager> EventLoopManagerSingleton;
類實例化，通過static等實現Singleton，EventLoopManagerSingleton::init()會創建對象
class EventLoopManager : public NonCopyable {
//---
private:
//! The audio request manager handles requests for all nanoapps and manages
//! the state of the audio subsystem that the runtime subscribes to.
AudioRequestManager mAudioRequestManager;
//! The event loop managed by this event loop manager.
EventLoop mEventLoop;
//! The GnssManager that handles requests for all nanoapps. This manages the
//! state of the GNSS subsystem that the runtime subscribes to.
GnssManager mGnssManager;
//! Handles communications with the host processor.
HostCommsManager mHostCommsManager;
//! The SensorRequestManager that handles requests for all nanoapps. This
//! manages the state of all sensors that runtime subscribes to.
SensorRequestManager mSensorRequestManager;
//! The WifiRequestManager that handles requests for nanoapps. This manages
//! the state of the wifi subsystem that the runtime subscribes to.
WifiRequestManager mWifiRequestManager;
//! The WwanRequestManager that handles requests for nanoapps. This manages
//! the state of the WWAN subsystem that the runtime subscribes to.
WwanRequestManager mWwanRequestManager;
//! The MemoryManager that handles malloc/free call from nanoapps and also
//! controls upper limits on the heap allocation amount.
MemoryManager mMemoryManager;
};
platform相關類的實現
platform/include/chre/platform/platform_sensor.h 目錄下有各種類的實現如PlatformSensor,但具體到不同platform有不同的實現方法，具體使用哪一個是通過編譯選項控制的。
platform/slpi下的代碼分爲SMGR、SEE兩類
SLPI是高通sensor DSP，代碼框架原來是SMGR,後來更新爲SEE
Sensor manager (SMGR) – Master of all sensor device drivers (DD);
handles all scheduling and sensor-client interface
Sensors Execution Environment (SEE) – New generation of sensor management software on
Qualcomm All-Ways AwareTM Hub (AAH) introduced in SDM845 in 2017 and implemented in
subsequent chipsets
還有兩個術語明確下：
µImage mode – Low Power mode – no double data rate (DDR)或者說靜態memory不需要動態刷新
bigImage mode – DDR in use
SMGR實現
SMGR的實現依賴slpi_proc的源碼，如果源碼沒有使用smgr框架就沒有對應的代碼，如下面的Sensors路徑
SEE實現
CHRE入口點
chre的入口點肯定包含 "chre::init()"，以chre在slpi上的實現爲例。CHRE host 通過 fastRPC 函數 chre_slpi_start_thread調用到slpi環境。
chre::init()
PlatformSensor中創建了SeeHelper並賦值了seeHelperCallback, 該callback的具體作用後面會看到；調用EventLoopMangerSingleton::init()創建對象EventLoopManger和其他manager對象
chreThreadEntry
調用qurt函數設置thread屬性創建線程後進入chreThreadEntry，最後進入整個控制流程EventLoop.run.
event的push/pop控制這整個代碼的流程。
sensor的data event事件是怎麼發送到event loop的
SeeHelper註冊了SeeHelperCallback::onSensorDataEvent,該函數會調用postEvent,至於callback函數是怎麼被調到的看上圖
chre_api
chre.h
chre api都是爲nanoapp服務的
re.h runtime environment
common.h
event.h
nanoapp.h
sensor
gnss/wifi/wwan
sensor chre_api的實現
bool chreSensorFindDefault(uint8_t sensorType, uint32_t *handle)
後面都依賴獲得的handle
chreSensorxxx的實現在文件chre_api_sensor.cc中，//todo
SensorRequestManager的構造函數
從getSuidAndAttrs 可以看出和see通信的過程encodeSnsSuidReq (encode成pb格式)，然後調用sendReq。這裏維護一個全局變量mSensorRequests, 獲得sensor infor等直接訪問該變量。
chreSensorConfigure
註冊當前的nanoapp接聽該事件。