原创 PowerButton驱动分析

PowerButton驱动分析<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

DWORD

PBT_Init(DWORD dwContext)

{

    DWORD   IDPowerButtonThread;

    DWORD   IDResetButtonThread;

    HMODULE hmCore;

    //

    // Obtain a pointer to the power manager function "SetSystemPowerState"

    // from the core library so we can call into it.

    //

    pfnSetSystemPowerState = NULL;

    hmCore = (HMODULE) LoadLibrary(_T("coredll.dll"));

    if(hmCore != NULL)

    {

        pfnSetSystemPowerState = (PFN_SetSystemPowerState) GetProcAddress(hmCore, _T("SetSystemPowerState"));

        if(pfnSetSystemPowerState == NULL)

        {

            FreeLibrary(hmCore);

        }

    }

    // Initialize addresses now as opposed to when interrupts are handled so there are no race conditions

    InitializeAddresses();//初始化硬件地址

    // Create a thread to handle the power button event, and one to handle the reset button event.

ResetButtonIntrThreadHandle = CreateThread( //返回线程句柄

0,//必须为0

    0, //忽略，线程堆栈大小由连接器设置决定

(LPTHREAD_START_ROUTINE)ResetButtonIntrThread,//指定线程函数名

 0,

 0,

 &IDResetButtonThread //使用IDResetButtonThread接收线程标志符

<?xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" />

    if (ResetButtonIntrThreadHandle == 0)

    {

        RETAILMSG(1, (TEXT("PBT: CreateThread() Fail\r\n")));

    }

    PowerButtonIntrThreadHandle = CreateThread(0, 0, (LPTHREAD_START_ROUTINE) PowerButtonIntrThread, 0, 0, &IDPowerButtonThread);

    if (PowerButtonIntrThreadHandle == 0)

    {

        RETAILMSG(1, (TEXT("PBT: CreateThread() Fail\r\n")));

    }

    return (dwContext);

}

static BOOL

InitializeAddresses(VOID)

{

    BOOL RetValue = FALSE;

    // IO Register Allocation

v_pIOPregs = (volatile S3C2410X_IOPORT_REG *)VirtualAlloc(

0, //分配内存的开始地址由系统指定

sizeof *v_pIOPregs,//分配内存大小

MEM_RESERVE,// 保留虚拟地址空间以便以后提交。

PAGE_NOACCESS//任何访问该区域的操作将被拒绝

);

    if (v_pIOPregs == NULL)

    {

        ERRORMSG(1,(TEXT("PBT: VirtualAlloc failed!\r\n")));

    } else {

        if (

!VirtualCopy(//绑定一块物理内存到当前进程虚拟地址空间

(PVOID)v_pIOPregs, //指针，指向虚拟地址的起始地址

(PVOID)(S3C2410X_BASE_REG_PA_IOPORT >> 8), //物理地址右移8位。

sizeof *v_pIOPregs, //保留空间的大小

PAGE_PHYSICAL | PAGE_READWRITE | PAGE_NOCACHE)//物理地址，可读可写，无缓存。

)

        {

            ERRORMSG(1,(TEXT("PBT: VirtualCopy failed!\r\n")));

            VirtualFree((PVOID)v_pIOPregs, 0, MEM_RELEASE);

            v_pIOPregs = NULL;

        }

    }

    s2410INT = (volatile S3C2410X_INTR_REG *)VirtualAlloc(0, sizeof *s2410INT, MEM_RESERVE, PAGE_NOACCESS);

    if (s2410INT == NULL)

    {

        ERRORMSG(1,(TEXT("PBT: VirtualAlloc failed!\r\n")));

    } else {

        if (!VirtualCopy((PVOID)s2410INT, (PVOID)(S3C2410X_BASE_REG_PA_INTR >> 8), sizeof *s2410INT, PAGE_PHYSICAL | PAGE_READWRITE | PAGE_NOCACHE))

        {

            ERRORMSG(1,(TEXT("PBT: VirtualCopy failed!\r\n")));

            VirtualFree((PVOID)s2410INT, 0, MEM_RELEASE);

            s2410INT = NULL;

        }

    }

    {

      RetValue = TRUE;

    }

    return (RetValue);

}

static DWORD

ResetButtonIntrThread(PVOID pArg)

{

    EnableResetButtonInterrupt();配置寄存器状态

ResetButtonIntrEvent = CreateEvent(  //创建事件, 成功返回一个事件对象句柄

NULL,//必须为NULL

FALSE,// 系统在等待线程被释放后自动重置状态为不可触发状态

FALSE,// 初始状态，为不可触发状态

NULL//创建事件对象没有名称

);

    //

    // Request a SYSINTR value from the OAL.

    //

if (

!KernelIoControl(    //根据IRQ获取一个SYSINTR

IOCTL_HAL_REQUEST_SYSINTR, //IO控制代码

&ResetButtonIrq,            //指向一个缓冲区，其包含执行操作所必须的数据IRQ

&ResetButtonSysIntr, //指向输出缓冲区，用来接收操作数据SYSINTR

NULL

))

    {

        RETAILMSG(1, (TEXT("PBT: Error! Failed to request sysintr value for reset button interrupt.\r\n")));

        return(0);

    }

if (!(InterruptInitialize(//关联SYSINTR和之前创建的事件

ResetButtonSysIntr,// 虚拟中断标示符

ResetButtonIntrEvent, //当中断触发时，同时触发ResetButtonIntrEvent事件。

0, //不适用数据块

0 //数据块大小为0

)))

    {

        RETAILMSG(1, (TEXT("ERROR: ResetButton: Interrupt initialize failed.\r\n")));

    }

    // Handle power button presses.

    for (;;)

    {

        WaitForSingleObject(//函数检查指定对象的当前状态。如果对象的状态为不可触发的。

//则调用线程进入一个高效率等待状态。在等待事件对象变为可触

//发或间隔时间超时，线程消耗很少的处理时间

ResetButtonIntrEvent, //指向事件的句柄

INFINITE//永不超时

);

//Mask the storage device interrupt EINT11 so we don't service it before reboot is finished

 s2410INT->INTMSK = (s2410INT->INTMSK | (0x1 << 0x5));

        if (ResetButtonIsPushed())     // Guard against noise triggering an interrupt.

        {

            //

            // Soft reset and standard suspend-resume both start with suspend for now.

            // Call whichever shutdown API is available.

            //

            if(pfnSetSystemPowerState != NULL)

            {

                RETAILMSG(1,(TEXT("PBT: Signalling power manager to reset...\r\n")));

                pfnSetSystemPowerState(NULL, POWER_STATE_RESET, POWER_FORCE);

            } else {

                RETAILMSG(1,(TEXT("PBT: Resetting by calling KernelIoControl(IOCTL_HAL_REBOOT)...\r\n")));

                KernelIoControl(IOCTL_HAL_REBOOT,NULL,0,NULL,0,NULL);

            }

            //

            // Acquiesce to other threads since our work is complete as of

            // the call to PowerOffSystem, or the signalling of the power

            // manager.

            //

            Sleep(0);

        }

        else

            RETAILMSG(1,(TEXT("PBT: Feeble button press or noise triggered it (ignored)\r\n")));

        InterruptDone(ResetButtonSysIntr);//该函数通知内核中断处理完毕

    }

}

总结：

中断驱动书写过程。

1.     设置物理地址到虚拟地址映射。因为wince启动后是对虚拟地址操作。InitializeAddresses

2.     创建一个线程。指定线程函数。获得线程句柄CreateThread

3.     配置GPIO口和中断寄存器状态。EnableResetButtonInterrupt

4.     创建一个事件。并初始化该事件为不可触发状态，自动触发。获得事件句柄CreateEvent

5.     根据IRQ获取一个SYSINTR KernelIoControl

6.     初始化，关联SYSINTR和之前创建的事件InterruptInitialize

7.     等待事件触发WaitForSingleObject

8.     处理中断进程

9.     通知内核中断处理完毕InterruptDone