// Power request handler Smart_Card driver
// Copyright (C) 1999, 2000 by Walter Oney
// All rights reserved

#include "stddcls.h"
#include "driver.h"

// TODO: all functions in this module are in the locked code segment even though the
// AddDevice function sets DO_POWER_PAGABLE. If you *know* that you'll never need a
// non-paged handler, you could move the DispatchPower and DefaultPowerHandler functions
// to PAGEDCODE. 

NTSTATUS DefaultPowerHandler(PDEVICE_EXTENSION pdx, IN PIRP Irp);

enum POWSTATE {
	InitialState = 0,				// initial state of FSM
	SysPowerUpPending,				// system power-up IRP forwarded
	SubPowerUpPending,				// waiting for nested device power up to finish
	SubPowerDownPending,			// waiting from device to power down before forwarding system power-down IRP
	SysPowerDownPending,			// waiting for system power-down IRP to finish
	DevPowerUpPending,				// waiting for device power-up IRP
	DevPowerDownPending,			// waiting for device power-down IRP
	ContextSavePending,				// context save is underway
	ContextRestorePending,			// context restore is underway
	DevQueryUpPending,				// device query for power-up pending
	DevQueryDownPending,			// device query for power-down pending
	QueueStallPending,				// waiting for device to be idle
	PassiveCompletePending,			// waiting to complete main IRP at PASSIVE_LEVEL
	FinalState,						// final state of FSM
	NUMPOWSTATES,
	};

enum POWEVENT {
	NewIrp = 0,						// new query/set IRP
	MainIrpComplete,				// the main IRP has finished
	AsyncNotify,					// some other event has occurred
	NUMPOWEVENTS,
	};

typedef struct _POWCONTEXT {
	LONG id;						// unique sequence number for this IRP
	LONG eventcount;				// number of events generated for this IRP
	PDEVICE_EXTENSION pdx;			// our own device extension
	PIRP irp;						// the IRP we're processing
	enum POWSTATE state;			// current state of FSM
	NTSTATUS status;				// completion status for main IRP
	DEVICE_POWER_STATE devstate;	// device power state to use
	DEVICE_POWER_STATE oldpower;	// previous device power state
	UCHAR MinorFunction;			// minor function to use in requested power IRP
	} POWCONTEXT, *PPOWCONTEXT;

NTSTATUS HandlePowerEvent(PPOWCONTEXT ctx, enum POWEVENT event);

static LONG ctxcount = 0;			// counter for POWCONTEXT structures

// #define VERBOSETRACE				// for debugging HandlePowerEvent

#if DBG

	#ifdef VERBOSETRACE
		#define POWTRACE(x) DbgPrint x
	#else
		#define POWTRACE(x)
	#endif

	static char* fcnname[] = {
		"IRP_MN_WAIT_WAKE",
		"IRP_MN_POWER_SEQUENCE",
		"IRP_MN_SET_POWER",
		"IRP_MN_QUERY_POWER",
		};

	static char* sysstate[] = {
		"PowerSystemUnspecified",
		"PowerSystemWorking",
		"PowerSystemSleeping1",
		"PowerSystemSleeping2",
		"PowerSystemSleeping3",
		"PowerSystemHibernate",
		"PowerSystemShutdown",
		"PowerSystemMaximum",
		};

	static char* devstate[] = {
		"PowerDeviceUnspecified",
		"PowerDeviceD0",
		"PowerDeviceD1",
		"PowerDeviceD2",
		"PowerDeviceD3",
		"PowerDeviceMaximum",
		};

#else
	#define POWTRACE(x)
#endif // DBG
									  
///////////////////////////////////////////////////////////////////////////////

#pragma LOCKEDCODE

NTSTATUS DispatchPower(IN PDEVICE_OBJECT fdo, IN PIRP Irp)
	{							// DispatchPower
	PAGED_CODE();
	PDEVICE_EXTENSION pdx = (PDEVICE_EXTENSION) fdo->DeviceExtension;
	NTSTATUS status = IoAcquireRemoveLock(&pdx->RemoveLock, Irp);
	if (!NT_SUCCESS(status))
			{
			PoStartNextPowerIrp(Irp);
			return CompleteRequest(Irp, status);
			}

	PIO_STACK_LOCATION stack = IoGetCurrentIrpStackLocation(Irp);
	ASSERT(stack->MajorFunction == IRP_MJ_POWER);

	ULONG fcn = stack->MinorFunction;

	if (fcn == IRP_MN_SET_POWER || fcn == IRP_MN_QUERY_POWER)
		{						// handle set/query

#if DBG
		KdPrint((DRIVERNAME " - POWER Request (%s)", fcnname[fcn]));
		if (stack->Parameters.Power.Type == SystemPowerState)
			KdPrint((", S-state = %s\n", sysstate[stack->Parameters.Power.State.SystemState]));
		else
			KdPrint((", D-state = %s\n", devstate[stack->Parameters.Power.State.DeviceState]));
#endif // DBG

		// Create a context structure and launch the finite state machine that will process
		// this IRP asynchronously. The initial call to HandlePowerEvent should return
		// STATUS_PENDING. The FSM will eventually complete the IRP.
		
		PPOWCONTEXT ctx = (PPOWCONTEXT) ExAllocatePool(NonPagedPool, sizeof(POWCONTEXT));
		if (!ctx)
			{
			KdPrint((DRIVERNAME " - Can't allocate power context structure\n"));
			PoStartNextPowerIrp(Irp);
			status = CompleteRequest(Irp, STATUS_INSUFFICIENT_RESOURCES);
			}
		else
			{				// process this IRP
			RtlZeroMemory(ctx, sizeof(POWCONTEXT));
			ctx->pdx = pdx;
			ctx->irp = Irp;
			ctx->id = InterlockedIncrement(&ctxcount);
			status = HandlePowerEvent(ctx, NewIrp);
			}				// process this IRP
		}						// handle set/query

	else
		{						// handle other power request
		KdPrint((DRIVERNAME " - POWER Request (%s)\n", fcn < arraysize(fcnname) ? fcnname[fcn] : "??"));
			status = DefaultPowerHandler(pdx, Irp);
		}						// handle other power request

	IoReleaseRemoveLock(&pdx->RemoveLock, Irp);
	return status;
	}							// DispatchPower

///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////

#pragma LOCKEDCODE

NTSTATUS DefaultPowerHandler(PDEVICE_EXTENSION pdx, IN PIRP Irp)
	{							// DefaultPowerHandler
	PoStartNextPowerIrp(Irp);	// must be done while we own the IRP
	IoSkipCurrentIrpStackLocation(Irp);
	return PoCallDriver(pdx->LowerDeviceObject, Irp);
	}							// DefaultPowerHandler

///////////////////////////////////////////////////////////////////////////////
// GetLowestDevicePowerState returns the lowest device power state that is
// consistent with a given system power state and the current wakeup state of
// the device.

DEVICE_POWER_STATE GetLowestDevicePowerState(PDEVICE_EXTENSION pdx, SYSTEM_POWER_STATE sysstate)
	{							// GetLowestDevicePowerState
	DEVICE_POWER_STATE maxstate = pdx->devcaps.DeviceState[sysstate];
	DEVICE_POWER_STATE minstate = PowerDeviceD3;

	DEVICE_POWER_STATE dstate = minstate > maxstate ? minstate : maxstate;
	
	// TODO choose a different dstate here if you want to

	return dstate;
	}							// GetLowestDevicePowerState

///////////////////////////////////////////////////////////////////////////////

#pragma LOCKEDCODE

VOID SendAsyncNotification(PVOID context)
	{							// SendAsyncNotification
	HandlePowerEvent((PPOWCONTEXT) context, AsyncNotify);
	}							// SendAsyncNotification

///////////////////////////////////////////////////////////////////////////////

struct SDSP_CONTEXT {
	PKEVENT pev;				// event to signal when request complete
	NTSTATUS status;			// ending status
	};

#pragma LOCKEDCODE

VOID SendDeviceSetPowerComplete(PDEVICE_OBJECT junk, UCHAR fcn, POWER_STATE state, SDSP_CONTEXT* context, PIO_STATUS_BLOCK pstatus)
	{							// SendDeviceSetPowerComplete
	context->status = pstatus->Status;
	KeSetEvent(context->pev, EVENT_INCREMENT, FALSE);
	}							// SendDeviceSetPowerComplete

NTSTATUS SendDeviceSetPower(PDEVICE_EXTENSION pdx, DEVICE_POWER_STATE devpower, BOOLEAN wait /* = FALSE */)
	{							// SendDeviceSetPower
	POWER_STATE state;
	state.DeviceState = devpower;
	NTSTATUS status;

	if (wait)
		{						// synchronous operation
		KEVENT event;
		KeInitializeEvent(&event, NotificationEvent, FALSE);
		SDSP_CONTEXT context = {&event};
		status = PoRequestPowerIrp(pdx->Pdo, IRP_MN_SET_POWER, state,
			(PREQUEST_POWER_COMPLETE) SendDeviceSetPowerComplete, &context, NULL);
		if (status == STATUS_PENDING)
			{
			KeWaitForSingleObject(&event, Executive, KernelMode, FALSE, NULL);
			status = context.status;
			}
		}						// synchronous operation
	else
		status = PoRequestPowerIrp(pdx->Pdo, IRP_MN_SET_POWER, state, NULL, NULL, NULL);
	
	return status;
	}							// SendDeviceSetPower

///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////

#pragma LOCKEDCODE

NTSTATUS MainCompletionRoutine(PDEVICE_OBJECT junk, PIRP Irp, PPOWCONTEXT ctx);
VOID PoCompletionRoutine(PDEVICE_OBJECT junk, UCHAR fcn, POWER_STATE state, PPOWCONTEXT ctx, PIO_STATUS_BLOCK pstatus);
NTSTATUS SafePoCallDriver(PDEVICE_OBJECT DeviceObject, PIRP Irp);
VOID PassivePowerComplete(PPOWCONTEXT ctx) {HandlePowerEvent(ctx, AsyncNotify);}

NTSTATUS HandlePowerEvent(PPOWCONTEXT ctx, enum POWEVENT event)
	{							// HandlePowerEvent
	NTSTATUS status = -1;		// an invalid value
	ASSERT(ctx);
	ASSERT((ULONG) event < NUMPOWEVENTS);

	PIRP Irp = ctx->irp;
	PIO_STACK_LOCATION stack = Irp ? IoGetCurrentIrpStackLocation(Irp) : NULL;

	PDEVICE_EXTENSION pdx = ctx->pdx;

	enum POWACTION {
		InvalidAction,			// code for invalid state/event combinations
		TriageNewIrp,			// decide what to do with new IRP
		QueueStallComplete,		// device queue has been stalled
		ForwardMainIrp,			// begin system or device IRP for more power
		SysPowerUpComplete,		// system power-up IRP completed
		SysPowerDownComplete,	// system power-down IRP completed
		SelectDState,			// choose D-state corresponding to main IRP's S-state
		SendDeviceIrp,			// send device IRP
		CompleteMainIrp,		// complete the main IRP
		DestroyContext,			// terminate FSM
		SubPowerUpComplete,		// nested power-up IRP finished or failed
		SubPowerDownComplete,	// nested power-down IRP finished or failed
		DevPowerUpComplete,		// device power-up IRP has completed
		SaveContext,			// save context in preparation for powering down
		ContextSaveComplete,	// device context has been saved
		ContextRestoreComplete,	// device context has been restored
		DevQueryUpComplete,		// device query for power-up complete
		DevQueryDown,			// see if device can power down
		DevQueryDownComplete,	// device query for power-down complete
		};

#ifdef VERBOSETRACE
	static char* powstatenames[] = {
		"InitialState",
		"SysPowerUpPending",
		"SubPowerUpPending",
		"SubPowerDownPending",
		"SysPowerDownPending",
		"DevPowerUpPending",
		"DevPowerDownPending",
		"ContextSavePending",
		"ContextRestorePending",
		"DevQueryUpPending",
		"DevQueryDownPending",
		"QueueStallPending",
		"SaveSeqPending",
		"RestoreSeqPending",
		"PassiveCompletePending",
		"FinalState",
		};

	static char* eventnames[] = {
		"NewIrp",
		"MainIrpComplete",
		"AsyncNotify",
		};

	static char* actionnames[] = {
		"InvalidAction",
		"TriageNewIrp",
		"QueueStallComplete",
		"ForwardMainIrp",
		"SysPowerUpComplete",
		"SysPowerDownComplete",
		"SelectDState",
		"SendDeviceIrp",
		"CompleteMainIrp",
		"DestroyContext",
		"SubPowerUpComplete",
		"SubPowerDownComplete",
		"DevPowerUpComplete",
		"SaveContext",
		"ContextSaveComplete",
		"ContextRestoreComplete",
		"DevQueryUpComplete",
		"DevQueryDown",
		"DevQueryDownComplete",
		"SendPowerSequence",
		"SaveSeqComplete",
		"ForwardDevDown",
		"RestoreSeqComplete",
		"RestoreContext",
		};
#endif // VERBOSETRACE

	static enum POWACTION actiontable[NUMPOWSTATES][NUMPOWEVENTS] = {
/*							NewIrp				MainIrpComplete				AsyncNotify	*/