/*++

Copyright (c) 2000 Microsoft Corporation

Module Name:

    sSPwr.c

Abstract:

    The power management related processing.

    The Power Manager uses IRPs to direct drivers to change system
    and device power levels, to respond to system wake-up events,
    and to query drivers about their devices. All power IRPs have
    the major function code IRP_MJ_POWER.

    Most function and filter drivers perform some processing for
    each power IRP, then pass the IRP down to the next lower driver
    without completing it. Eventually the IRP reaches the bus driver,
    which physically changes the power state of the device and completes
    the IRP.

    When the IRP has been completed, the I/O Manager calls any
    IoCompletion routines set by drivers as the IRP traveled
    down the device stack. Whether a driver needs to set a completion
    routine depends upon the type of IRP and the driver's individual
    requirements.

    This code is not USB specific. It is essential for every WDM driver
    to handle power irps.

Environment:

    Kernel mode

Notes:

    Copyright (c) 2000 Microsoft Corporation.  
    All Rights Reserved.

--*/

#include "selSusp.h"
#include "sSPwr.h"
#include "sSPnP.h"
#include "sSDevCtr.h"
#include "sSUsr.h"
#include "sSWmi.h"

NTSTATUS
SS_DispatchPower(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )
/*++
 
Routine Description:

    The power dispatch routine.

Arguments:

    DeviceObject - pointer to a device object.

    Irp - pointer to an I/O Request Packet.

Return Value:

    NT status code

--*/
{
    NTSTATUS           ntStatus;
    PIO_STACK_LOCATION irpStack;
    PUNICODE_STRING    tagString;
    PDEVICE_EXTENSION  deviceExtension;
	
    //
    // initialize the variables
    //
	
    irpStack = IoGetCurrentIrpStackLocation(Irp);
    deviceExtension = (PDEVICE_EXTENSION)DeviceObject->DeviceExtension;

    //
    // We don't queue power Irps, we'll only check if the
    // device was removed, otherwise we'll take appropriate
    // action and send it to the next lower driver. In general
    // drivers should not cause long delays while handling power
    // IRPs. If a driver cannot handle a power IRP in a brief time,
    // it should return STATUS_PENDING and queue all incoming
    // IRPs until the IRP completes.
    //

    if(Removed == deviceExtension->DeviceState) {

        //
        // Even if a driver fails the IRP, it must nevertheless call
        // PoStartNextPowerIrp to inform the Power Manager that it
        // is ready to handle another power IRP.
        //

        PoStartNextPowerIrp(Irp);

        Irp->IoStatus.Status = ntStatus = STATUS_DELETE_PENDING;
        Irp->IoStatus.Information = 0;

        IoCompleteRequest(Irp, IO_NO_INCREMENT);

        return ntStatus;
    }

    if(NotStarted == deviceExtension->DeviceState) {

        //
        // if the device is not started yet, pass it down
        //

        PoStartNextPowerIrp(Irp);

        IoSkipCurrentIrpStackLocation(Irp);

        return PoCallDriver(deviceExtension->TopOfStackDeviceObject, Irp);
    }

    SSDbgPrint(3, ("SS_DispatchPower::"));
    SSIoIncrement(deviceExtension);
    
    switch(irpStack->MinorFunction) {
    
    case IRP_MN_SET_POWER:

        //
        // The Power Manager sends this IRP for one of the
        // following reasons:
        // 1) To notify drivers of a change to the system power state.
        // 2) To change the power state of a device for which
        //    the Power Manager is performing idle detection.
        // A driver sends IRP_MN_SET_POWER to change the power
        // state of its device if it's a power policy owner for the
        // device.
        //

        //
        // Mark the Irp as pending and return STATUS_PENDING if we change the 
        // nature of the irp in the completion routine (asynchroniticity).
        // In such cases, do not return the status returned by the lower driver.
        // returning STATUS_MORE_PROCESSING_REQUIRED in the completion routine 
        // transforms the nature of the irp to asynchronous irp.
        //

        IoMarkIrpPending(Irp);

        switch(irpStack->Parameters.Power.Type) {

        case SystemPowerState:

            HandleSystemSetPower(DeviceObject, Irp);

            ntStatus = STATUS_PENDING;

            break;

        case DevicePowerState:

            HandleDeviceSetPower(DeviceObject, Irp);

            ntStatus = STATUS_PENDING;

            break;
        }

        break;

    case IRP_MN_QUERY_POWER:

        //
        // The Power Manager sends a power IRP with the minor
        // IRP code IRP_MN_QUERY_POWER to determine whether it
        // can safely change to the specified system power state
        // (S1-S5) and to allow drivers to prepare for such a change.
        // If a driver can put its device in the requested state,
        // it sets status to STATUS_SUCCESS and passes the IRP down.
        //

        IoMarkIrpPending(Irp);
    
        switch(irpStack->Parameters.Power.Type) {

        case SystemPowerState:
            
            HandleSystemQueryPower(DeviceObject, Irp);

            ntStatus = STATUS_PENDING;

            break;

        case DevicePowerState:

            HandleDeviceQueryPower(DeviceObject, Irp);

            ntStatus = STATUS_PENDING;

            break;
        }

        break;

    case IRP_MN_WAIT_WAKE:

        //
        // The minor power IRP code IRP_MN_WAIT_WAKE provides
        // for waking a device or waking the system. Drivers
        // of devices that can wake themselves or the system
        // send IRP_MN_WAIT_WAKE. The system sends IRP_MN_WAIT_WAKE
        // only to devices that always wake the system, such as
        // the power-on switch.
        //

        IoMarkIrpPending(Irp);

        IoCopyCurrentIrpStackLocationToNext(Irp);

        IoSetCompletionRoutine(
                        Irp,
                        (PIO_COMPLETION_ROUTINE)WaitWakeCompletionRoutine,
                        deviceExtension, 
                        TRUE, 
                        TRUE, 
                        TRUE);

        PoStartNextPowerIrp(Irp);

        ntStatus = PoCallDriver(deviceExtension->TopOfStackDeviceObject, Irp);

        if(!NT_SUCCESS(ntStatus)) {

            SSDbgPrint(1, ("Lower drivers failed the IRP_MN_WAIT_WAKE Irp"));
        }

        //
        // since we marked the Irp as pending; we should return STATUS_PENDING
        //
        ntStatus = STATUS_PENDING;

        //
        // push back the count HERE and NOT in completion routine
        // a pending Wait Wake Irp should not impede stopping the device
        //

        SSDbgPrint(3, ("IRP_MN_WAIT_WAKE::"));
        SSIoDecrement(deviceExtension);

        break;

    case IRP_MN_POWER_SEQUENCE:

        //
        // A driver sends this IRP as an optimization to determine
        // whether its device actually entered a specific power state.
        // This IRP is optional. Power Manager cannot send this IRP.
        //

    default:

        PoStartNextPowerIrp(Irp);

        IoSkipCurrentIrpStackLocation(Irp);

        ntStatus = PoCallDriver(deviceExtension->TopOfStackDeviceObject, Irp);

        if(!NT_SUCCESS(ntStatus)) {

            SSDbgPrint(1, ("Lower drivers failed this Irp"));
        }
        
        SSDbgPrint(3, ("SS_DispatchPower::"));
        SSIoDecrement(deviceExtension);

        break;
    }

    return ntStatus;
}

NTSTATUS
HandleSystemQueryPower(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )
/*++
 
Routine Description:

    This routine handles the irp with minor function of type IRP_MN_QUERY_POWER
    for the system power states.

Arguments:

    DeviceObject - pointer to device object
    Irp - I/O request packet sent by the power manager.

Return Value:

    NT status value

--*/
{
    NTSTATUS           ntStatus;
    PDEVICE_EXTENSION  deviceExtension;
    SYSTEM_POWER_STATE systemState;
    PIO_STACK_LOCATION irpStack;
    
    SSDbgPrint(3, ("HandleSystemQueryPower - begins\n"));

    //
    // initialize variables
    //

    deviceExtension = (PDEVICE_EXTENSION)DeviceObject->DeviceExtension;
    irpStack = IoGetCurrentIrpStackLocation(Irp);
    systemState = irpStack->Parameters.Power.State.SystemState;

    //
    // Fail a query for a power state incompatible with waking up the system
    //

    SSDbgPrint(3, ("Query for a system power state S%X\n"
                   "Current system power state S%X\n",
                   systemState - 1,
                   deviceExtension->SysPower - 1));

    if((deviceExtension->WaitWakeEnable) &&
       (systemState > deviceExtension->DeviceCapabilities.SystemWake)) {

        SSDbgPrint(3, ("query for an incompatible power state\n"));

        PoStartNextPowerIrp(Irp);

        Irp->IoStatus.Status = ntStatus = STATUS_INVALID_DEVICE_STATE;
        Irp->IoStatus.Information = 0;

        IoCompleteRequest(Irp, IO_NO_INCREMENT);

        SSDbgPrint(3, ("HandleSystemQueryPower::"));
        SSIoDecrement(deviceExtension);

        return ntStatus;
    }

    //
    // if querying for a lower S-state, issue a wait-wake
    // also, it is mandatory to have this Irp pending below
    // before we send any of the low power irps.
    //

    if((systemState > deviceExtension->SysPower) &&
       (deviceExtension->WaitWakeEnable)) {

        IssueWaitWake(deviceExtension);
    }

    IoCopyCurrentIrpStackLocationToNext(Irp);

    IoSetCompletionRoutine(
            Irp, 
            (PIO_COMPLETION_ROUTINE)SysPoCompletionRoutine,
            deviceExtension, 
            TRUE, 
            TRUE, 
            TRUE);

    ntStatus = PoCallDriver(deviceExtension->TopOfStackDeviceObject, Irp);

    SSDbgPrint(3, ("HandleSystemQueryPower - ends\n"));

    return STATUS_PENDING;
}

NTSTATUS
HandleSystemSetPower(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )
/*++
 
Routine Description:

    This routine services irps of minor type IRP_MN_SET_POWER
    for the system power state

Arguments:

    DeviceObject - pointer to device object
    Irp - I/O request packet sent by the power manager

Return Value:

    NT status value

--*/
{
    NTSTATUS           ntStatus;
    PDEVICE_EXTENSION  deviceExtension;
    SYSTEM_POWER_STATE systemState;
    PIO_STACK_LOCATION irpStack;
    
    SSDbgPrint(3, ("HandleSystemSetPower - begins\n"));

    //
    // initialize variables
    //

    deviceExtension = (PDEVICE_EXTENSION)DeviceObject->DeviceExtension;
    irpStack = IoGetCurrentIrpStackLocation(Irp);
    systemState = irpStack->Parameters.Power.State.SystemState;

    SSDbgPrint(3, ("Set request for a system power state S%X\n"
                   "Current system power state S%X\n", 
                   systemState - 1,
                   deviceExtension->SysPower - 1));

    //
    // pass the irp down the stack
    //
    IoCopyCurrentIrpStackLocationToNext(Irp);

    IoSetCompletionRoutine(
            Irp, 
            (PIO_COMPLETION_ROUTINE)SysPoCompletionRoutine,
            deviceExtension, 
            TRUE, 
            TRUE, 
            TRUE);

    ntStatus = PoCallDriver(deviceExtension->TopOfStackDeviceObject, Irp);

    SSDbgPrint(3, ("HandleSystemSetPower - ends\n"));

    return STATUS_PENDING;
}

NTSTATUS
HandleDeviceQueryPower(
    PDEVICE_OBJECT DeviceObject,
    PIRP           Irp
    )
/*++

Routine Description:

    This routine services irps of minor type IRP_MN_QUERY_POWER
    for the device power state

Arguments:

    DeviceObject - pointer to device object
    Irp - I/O request packet sent by the power manager

Return Value:

    NT status value

--*/
{
    NTSTATUS           ntStatus;
    PDEVICE_EXTENSION  deviceExtension;
    PIO_STACK_LOCATION irpStack;
    DEVICE_POWER_STATE deviceState;

    SSDbgPrint(3, ("HandleDeviceQueryPower - begins\n"));

    //
    // initialize variables
    //

    deviceExtension = (PDEVICE_EXTENSION) DeviceObject->DeviceExtension;
    irpStack = IoGetCurrentIrpStackLocation(Irp);
    deviceState = irpStack->Parameters.Power.State.DeviceState;

    SSDbgPrint(3, ("Query for a device power state D%X\n"
                   "Current device power state D%X\n", 
                   deviceState - 1,
                   deviceExtension->DevPower - 1));

    if(deviceExtension->WaitWakeEnable &&
       deviceState > deviceExtension->DeviceCapabilities.DeviceWake) {

        SSDbgPrint(3, ("query for an incompatible power state\n"));

        PoStartNextPowerIrp(Irp);

        Irp->IoStatus.Status = ntStatus = STATUS_INVALID_DEVICE_STATE;
        Irp->IoStatus.Information = 0;

        IoCompleteRequest(Irp, IO_NO_INCREMENT);

        SSDbgPrint(3, ("HandleDeviceQueryPower::"));
        SSIoDecrement(deviceExtension);

        return ntStatus;
    }

    if(deviceState < deviceExtension->DevPower) {

        ntStatus = STATUS_SUCCESS;
    }
    else {

        ntStatus = HoldIoRequests(DeviceObject, Irp);

        if(STATUS_PENDING == ntStatus) {

            return ntStatus;
        }
    }

    //
    // on error complete the Irp.
    // on success pass it to the lower layers
    //

    PoStartNextPowerIrp(Irp);

    Irp->IoStatus.Status = ntStatus;
    Irp->IoStatus.Information = 0;

    if(!NT_SUCCESS(ntStatus)) {

        IoCompleteRequest(Irp, IO_NO_INCREMENT);
    }
    else {

        IoSkipCurrentIrpStackLocation(Irp);

        ntStatus = PoCallDriver(deviceExtension->TopOfStackDeviceObject, Irp);
    }

    SSDbgPrint(3, ("HandleDeviceQueryPower::"));
    SSIoDecrement(deviceExtension);

    SSDbgPrint(3, ("HandleDeviceQueryPower - ends\n"));

    return ntStatus;
}


NTSTATUS
SysPoCompletionRoutine(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp,
    IN PDEVICE_EXTENSION DeviceExtension
    )
/*++
 
Routine Description:

    This is the completion routine for the system power irps of minor
    function types IRP_MN_QUERY_POWER and IRP_MN_SET_POWER.
    This completion routine sends the corresponding device power irp and
    returns STATUS_MORE_PROCESSING_REQUIRED. The system irp is passed as a
    context to the device power irp completion routine and is completed in
    the device power irp completion routine.

Arguments:

    DeviceObject - pointer to device object
    Irp - I/O request packet