原来认真写**是多么辛苦的事啊!佩服老hot那么高产... 大家有空请指正. ----------
系统下面许多设备,比如键盘,串口,触摸屏,硬盘......这些设备什么时候被系统使用的?这些设备怎样被系统使用的?加载过程是怎么样的?设备如何加入系统协同工作的?为什么系统能检测到并使用即插即用的设备(如usb鼠标)?系统是怎么控制设备的电源的?
CE管理设备的程序叫做DEVICE.EXE,这是一个独立的用户级进程,它主要负责跟踪,维护系统的设备信息并对设备资源进行调配.设备管理器包括即插即用设备管理,电源管理,io资源管理等等.
结构示意图:
目录树:c:\WINCE500\PRIVATE\WINCEOS\COREOS\DEVICE\
[DEVCORE] 设备管理器的核心代码部分. Devapi.c Devcore.c Devfile.c Devfsd.c Devload.c De***p.c Celogdev.h [DEVMAIN] 程序入口点. devmain.c [INC] 头文件 Devmgrif.h Devmgrp.h Devzones.h Iormif.h Pmif.h [IORM] io资源管理 Iorm.c [NOPMIF] 电源管理模块接口(这里是不要电源管理模块的'空'接口) Nopmif.c [PMIF] 电源管理模块接口 Pmif.c
源码分析:(按照先后执行顺序来分析源代码.)
在[DEVMAIN]中有一个devmain.c的代码,这是device.exe的入口点.如同标准c的main()函数所在,因为是windows所以入口点是WinMain()这样的函数.在WinMain()内没有其他内容,只调用了StartDeviceManager()这个函数. int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPWSTR lpCmdLine, int nCmdShow) { int status; status = StartDeviceManager(hInst, hPrevInst, lpCmdLine, nCmdShow); return status; }
前面WinMain()调用的StartDeviceManager()函数位于devcore.c. 这个函数初始化设备管理器,电源管理器,IO资源管理,然后启动设备管理器,开始负责设备驱动的加载和卸载工作.
int WINAPI StartDeviceManager(HINSTANCE hInst, HINSTANCE hPrevInst, LPWSTR lpCmdLine, int nCmShow) {
HINSTANCE hCeddkDll; HANDLE hEvent;
if (IsAPIReady(SH_DEVMGR_APIS)) { return 0; } DEBUGREGISTER(NULL); DEBUGMSG(ZONE_BOOTSEQ, (TEXT("DEVICE: Starting boot phase 1\n")));
// PHASE 1 g_BootPhase = 1; //用一个全局变量来表示现在处于启动的哪个阶段.一共有3个阶段. // 0表示还没有开始启动;1表示在搜索注册表的值;2表示在加载设备; // 3表示已经开始正常运行了. InitOOMSettings(); // 初始化OOM. InitializeListHead(&g_DevChain); // 初始化常规状态设备列表 InitializeListHead(&g_ActivatingDevs); // 初始化激活的已经注册的设备列表 InitializeListHead(&g_DyingDevs); // 初始化消亡状态的设备列表 InitializeListHead(&g_CandidateDevs); // 初始化正在加载的设备驱动列表. g_hCleanEvt = CreateEvent(NULL, FALSE, FALSE, NULL); g_hDevApiHandle = CreateAPISet("WFLD", NUM_FDEV_APIS, FDevApiMethods, FDevApiSigs); // 向系统注册api g_hDevFileApiHandle = CreateAPISet("W32D", NUM_FAPIS, DevFileApiMethods, DevFileApiSigs); // 向系统注册api RegisterAPISet(g_hDevFileApiHandle, HT_FILE | REGISTER_APISET_TYPE); InitializePnPNotifications(); // 这个程序将调用StartDeviceNotifyThread() // 这将启动一个线程.它的具体实现在de***p.c文件中. InitializeCriticalSection(&g_devcs); // 初始化临界区. ResourceInitModule(); // 初始化一个全局变量gdwMaxDenseResources // 根据注册表来初始化设备管理资源 ResourceInitFromRegistry(TEXT("Drivers\\Resources"));
SetPowerOffHandler((FARPROC) DevMgrPowerOffHandler); RegisterAPISet(g_hDevApiHandle, SH_DEVMGR_APIS); InitDeviceFilesystems();
// Indicate that the device manager is up and running hEvent = OpenEvent(EVENT_ALL_ACCESS, FALSE, _T("SYSTEM/DevMgrApiSetReady")); DEBUGCHK(hEvent != NULL); if (hEvent != NULL) { SetEvent(hEvent); // 设置一个全局事件.通知别的程序设备管理器api已经准备好了. // 在其他的应用里面,使用设备管理器api前,如果希望确认设备管理器 // 的api已经注册好,它会等待这样一个事件. CloseHandle(hEvent); }
// Calibrate stall counter that is used for StallExecution // 以下代码调用ceddk.dll里面的fnCalibrateStall()函数. hCeddkDll = LoadLibrary (TEXT("ceddk.dll")); if (NULL != hCeddkDll) { pCalibrateStallFn fnCalibrateStall = (pCalibrateStallFn)\ GetProcAddress(hCeddkDll, TEXT("CalibrateStallCounter")); if (!fnCalibrateStall) { DEBUGMSG(ZONE_BOOTSEQ, (L"GetProcAddress failed on ceddk.dll\r\n")); FreeLibrary(hCeddkDll); } else { fnCalibrateStall(); } }
// Call the power manager initialization entry point PM_Init(); // 初始化电源管理模块.电源管理模块是一个pm.dll.它也被device.exe调用.这里 // 暂时不打算涉及电源管理部分.简单来说:在PM_Init()函数里面会启动3个线程, // PnpThreadProc,ResumeThreadProc, ActivityTimersThreadProc // 它们各自负责监控即插即用,Resume,和激活定时器 PM_SetSystemPowerState(NULL, POWER_STATE_ON, POWER_FORCE);//设置系统电源开.
// See if we are going to have two boot phases // 根据注册表内容,决定采用怎样的加载过程. // 如果存在SYSTEM/BootPhase1.分2个步骤来加载: // 先DevloadInit()加载一次,然后等待通知后,继续调用InitDevice()加载. // 如果没有SYSTEM/BootPhase1,则调用DevloadInit()一次完成. // 也许是满足一些需要2次加载设备的情况,所以留下这个功能. hEvent = OpenEvent(EVENT_ALL_ACCESS, FALSE, _T("SYSTEM/BootPhase1")); if (hEvent != NULL) { // Load phase 1 drivers from the boot registry DevloadInit(); // 加载设备.DevloadInit()函数位于devload.c,它首先删除注册表里面 // Device\Active,然后调用InitDevices()函数加载设备驱动.
// Signal boot phase 1 complete SetEvent(hEvent); // 发出通知,阶段1已经完成. CloseHandle(hEvent);
// Wait for phase 2 of the boot to begin // 等待通知后进入阶段2 hEvent = OpenEvent(EVENT_ALL_ACCESS, FALSE, TEXT("SYSTEM/BootPhase2")); DEBUGCHK(hEvent); if (hEvent) { DEBUGMSG(ZONE_BOOTSEQ, (TEXT("DEVICE: Started, waiting for boot phase 2\r\n"))); WaitForSingleObject(hEvent, INFINITE); CloseHandle(hEvent); }
// Load any new drivers from the persistent registry. Since the // registry may have changed, update the power state for any devices // that need it. DEBUGMSG(ZONE_BOOTSEQ, (TEXT("DEVICE: Second-phase driver load\r\n"))); g_BootPhase = 2; PM_SetSystemPowerState(NULL, POWER_STATE_ON, POWER_FORCE); InitDevices(NULL); // DevInit()加载会先清空注册表Acitve下的内容, // 第二次加载不能把前面一次的清空,所以这里不能用DevInit(). DEBUGMSG(ZONE_BOOTSEQ, (TEXT("DEVICE: Startup sequence complete\r\n"))); SignalStartedUsingReg(); // SignalStarted call with the right args } else { DEBUGMSG(ZONE_BOOTSEQ, (TEXT("DEVICE: No boot registry - skipping to boot phase 2\n"))); g_BootPhase = 2; DevloadInit(); SignalStarted(_wtol(lpCmdLine)); }
// Boot phase 3 isn't any different from phase 2; just marks that we got here. DEBUGMSG(ZONE_BOOTSEQ, (TEXT("DEVICE: Finished loading primary drivers - entering boot phase 3\n"))); g_BootPhase = 3; // 进入阶段3,同时也标志设备管理器开始运行了. CELOG_DeviceFinished (); // 记录日志. while (1) { WaitForSingleObject(g_hCleanEvt, INFINITE);
// check for auto-deregister devs first as they may end up queuing // themselves on the dying devs list ProcessAutoDeregisterDevs(); ProcessDyingDevs(); ProcessDyingOpens(); } return 1; // should not ever be reached }
加载设备的函数,DevloadInit()事实上也是调用InitDevices来实现,只不过事先清空了Acitve下的注册表内容
void DevloadInit(void) { DEBUGMSG(ZONE_INIT, (TEXT("DEVICE!DevloadInit\r\n"))); #define PHASE_1_BUSNAME TEXT("BuiltInPhase1") // // Delete the HLM\Drivers\Active key since there are no active devices at // init time. // 清空注册表Active下的内容. RegDeleteKey(HKEY_LOCAL_MACHINE, s_ActiveKey);
#ifdef DEBUG v_NextDeviceNum = 0xFFFFFFF0; // expect wraparound #else // DEBUG v_NextDeviceNum = 1; #endif // DEBUG g_bSystemInitd = FALSE; InitDevices(PHASE_1_BUSNAME); }
InitDevices(LPCTSTR lpBusName ) { HKEY RootKey; DWORD status; DWORD ValType; DWORD ValLen; TCHAR RootKeyPath[REG_PATH_LEN]; TCHAR BusName[DEVKEY_LEN]; REGINI reg[1]; DWORD dwRegCount=0;
// // Open HLM\Drivers key // 打开注册表HLM\Drivers. status = RegOpenKeyEx( HKEY_LOCAL_MACHINE, DEVLOAD_DRIVERS_KEY, // DEVLOAD_DRIVERS_KEY= "Drivers" 0, 0, &RootKey); if (status != ERROR_SUCCESS) { DEBUGMSG(ZONE_ROOT|ZONE_ERROR, (TEXT("DEVICE!InitDevices RegOpenKeyEx(%s) returned %d.\r\n"), DEVLOAD_DRIVERS_KEY, status)); return; }
// // Look for root key value; if not found use current Root Key as default, // otherwise open new root key // 查询注册表中 RootKey的值,一般这个值是Devices\BuildIn.将查询的值保存到RootKeyPath. // 如果没有指定,则使用Devices来替代. ValLen = sizeof(RootKeyPath); status = RegQueryValueEx( RootKey, DEVLOAD_ROOTKEY_VALNAME, // DEVLOAD_ROOTKEY_VALNAME =RootKey NULL, &ValType, (PUCHAR)RootKeyPath, &ValLen); RootKeyPath[ARRAYSIZE(RootKeyPath) - 1] = 0; if (status != ERROR_SUCCESS) { // Root key value not found, thus root key is Drivers _tcscpy(RootKeyPath, DEVLOAD_DRIVERS_KEY); // 没有找到,使用Devices来替代. }
// Close previous root key RegCloseKey(RootKey); DEBUGMSG(1, (L"DEVICE!InitDevices: Root Key is %s.\r\n", RootKeyPath)); // 为ActiveDeviceEx准备参数reg. 如果输入参数lpBusName指定了,则从参数lpBusName获得, // 否则从注册表中读取. if (lpBusName!=NULL) { reg[0].lpszVal = DEVLOAD_BUSNAME_VALNAME; reg[0].dwType = DEVLOAD_BUSNAME_VALTYPE; reg[0].pData = (PBYTE) lpBusName ; reg[0].dwLen = (_tcslen( lpBusName ) + 1) * sizeof(TCHAR); dwRegCount = 1; } else { status = RegOpenKeyEx( HKEY_LOCAL_MACHINE, RootKeyPath,0,0, &RootKey); if (status == ERROR_SUCCESS ) { ValLen = sizeof( BusName); status = RegQueryValueEx( RootKey, DEVLOAD_BUSNAME_VALNAME, NULL, &ValType, (PUCHAR)BusName, &ValLen); if (status == ERROR_SUCCESS && ValType==DEVLOAD_BUSNAME_VALTYPE) { // We found Bus Name. This is new bus driver model. So we use new format. BusName[DEVKEY_LEN-1] = 0; reg[0].lpszVal = DEVLOAD_BUSNAME_VALNAME; reg[0].dwType = DEVLOAD_BUSNAME_VALTYPE; reg[0].pData = (PBYTE)BusName; reg[0].dwLen = ValLen; dwRegCount = 1; } // Close previous root key RegCloseKey(RootKey); } } // Someday we'll want to track the handle returned by ActivateDevice so that // we can potentially deactivate it later. But since this code refers only to // builtin (ie, static) devices, we can just throw away the key. if (dwRegCount) ActivateDeviceEx(RootKeyPath,reg,dwRegCount,NULL); else ActivateDevice(RootKeyPath, 0); } // InitDevices
至此,已经明确了系统是通过InitDevice()来加载驱动,更具体的InitDevice()会调用ActivateDeviceEx()来加载驱动,但是,这里只加载了一个驱动啊,难道系统就只加载一次? 这个唯一被加载的驱动是BusEnum.dll(在CE4.2是RegEnum.dll)这个驱动位于public下,它枚举了BuiltIn下所有的设备,逐个加载,并在Active下记录成功加载的设备. |