/*++

Copyright (c) Microsoft Corporation.  All rights reserved.

    THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
    KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
    PURPOSE.

Module Name:

    HwSim.c

Abstract:
    This module implements a simple hardware simulator that simulates reading of
    data from the device's components. In this sample, the "data" that is read 
    is simply the bitwise complement of the component number. In other words, 
    the data for component number 'X' is simply '~X'.

    The hardware simulator also verifies that when a component is read, the 
    device is in D0. If not, it breaks into the debugger.

Environment:

    User mode

--*/

#include "include.h"
#include "HwSim.h"
#include "HwSim.tmh"

NTSTATUS
HwSimInitialize(
    _In_ WDFDEVICE Device
    )
/*++
Routine Description:

    This routine initializes the hardware simulator

Arguments:

    Device - Handle to the framework device object

Return Value:

    An NTSTATUS value representing success or failure of the function.

--*/
{
    NTSTATUS status;
    WDF_OBJECT_ATTRIBUTES objectAttributes;
    PHWSIM_CONTEXT devCtx;

    //
    // Allocate our context for this device
    //
    WDF_OBJECT_ATTRIBUTES_INIT_CONTEXT_TYPE(&objectAttributes, 
                                            HWSIM_CONTEXT);
    status = WdfObjectAllocateContext((WDFOBJECT) Device,
                                      &objectAttributes,
                                      (PVOID*) &devCtx);
    if (FALSE == NT_SUCCESS(status)) {
        Trace(TRACE_LEVEL_ERROR, 
              "%!FUNC! - WdfObjectAllocateContext failed with %!status!", 
              status);
        goto exit;
    }

    devCtx->FirstD0Entry = TRUE;

    status = STATUS_SUCCESS;
    
exit:
    return status;
}

VOID
HwSimD0Entry(
    _In_ WDFDEVICE Device
    )
/*++
Routine Description:

    This routine simulates the device entering D0

Arguments:

    Device - Handle to the framework device object

Return Value:

    None

--*/
{
    PHWSIM_CONTEXT devCtx;

    devCtx = HwSimGetDeviceContext(Device);

    if (devCtx->FirstD0Entry) {
        devCtx->FirstD0Entry = FALSE;
    }

    devCtx->DevicePoweredOn = TRUE;
    
    return;
}
    
VOID
HwSimD0Exit(
    _In_ WDFDEVICE Device
    )
/*++
Routine Description:

    This routine simulates the device exiting D0

Arguments:

    Device - Handle to the framework device object

Return Value:

    None

--*/
{
    PHWSIM_CONTEXT devCtx;

    devCtx = HwSimGetDeviceContext(Device);

    devCtx->DevicePoweredOn = FALSE;
    
    return;
}

ULONG
HwSimReadComponent(
    _In_ WDFDEVICE Device
    )
/*++
Routine Description:

    This routine simulates the reading of data from a component

Arguments:

    Device - Handle to the framework device object

    Component - Component from which data is being read

Return Value:

    A ULONG value representing the data that was read from the component

--*/
{
    ULONG componentData;
    PHWSIM_CONTEXT devCtx;
    ULONG component = 0;

    devCtx = HwSimGetDeviceContext(Device);
    
    //
    // Verify that the device is powered on
    //
    if (FALSE == devCtx->DevicePoweredOn) {
        //
        // This means that our driver is attempting to read from the component
        // while the device is not powered on.
        //
        Trace(TRACE_LEVEL_ERROR, 
              "%!FUNC! - Expected device to be powered on, but it was not.");

        WdfVerifierDbgBreakPoint();
    }

    assert(devCtx->DevicePoweredOn);

    //
    // In this sample, component data is just a bit-wise complement of the 
    // component number.
    //
    componentData = ~component;
    return componentData;
}