rw.c File Reference

#include "serial.h"
#include <debug.h>

Include dependency graph for rw.c:

Go to the source code of this file.

Functions
static PVOID	SerialGetUserBuffer (IN PIRP Irp)
static VOID	ReadBytes (IN PDEVICE_OBJECT DeviceObject, IN PIRP Irp, PWORKITEM_DATA WorkItemData)
static VOID NTAPI	SerialReadWorkItem (IN PDEVICE_OBJECT DeviceObject, IN PVOID pWorkItemData)
NTSTATUS NTAPI	SerialRead (IN PDEVICE_OBJECT DeviceObject, IN PIRP Irp)
NTSTATUS NTAPI	SerialWrite (IN PDEVICE_OBJECT DeviceObject, IN PIRP Irp)

Variables
static IO_WORKITEM_ROUTINE	SerialReadWorkItem

Function Documentation

ReadBytes()

static VOID ReadBytes ( IN PDEVICE_OBJECT  DeviceObject, IN PIRP  Irp, PWORKITEM_DATA  WorkItemData  )

static

Definition at line 28 of file rw.c.

{
    PSERIAL_DEVICE_EXTENSION DeviceExtension;
    ULONG Length;
    PUCHAR Buffer;
    UCHAR ReceivedByte;
    KTIMER TotalTimeoutTimer;
    KIRQL Irql;
    ULONG ObjectCount;
    PVOID ObjectsArray[2];
    ULONG_PTR Information = 0;
    NTSTATUS Status;

    ASSERT(DeviceObject);
    ASSERT(WorkItemData);

    DeviceExtension = (PSERIAL_DEVICE_EXTENSION)DeviceObject->DeviceExtension;
    Length = IoGetCurrentIrpStackLocation(Irp)->Parameters.Read.Length;
    Buffer = SerialGetUserBuffer(Irp);

    INFO_(SERIAL, "UseIntervalTimeout = %s, IntervalTimeout = %lu\n",
        WorkItemData->UseIntervalTimeout ? "YES" : "NO",
        WorkItemData->UseIntervalTimeout ? WorkItemData->IntervalTimeout.QuadPart : 0);
    INFO_(SERIAL, "UseTotalTimeout = %s\n",
        WorkItemData->UseTotalTimeout ? "YES" : "NO");

    ObjectCount = 1;
    ObjectsArray[0] = &DeviceExtension->InputBufferNotEmpty;
    if (WorkItemData->UseTotalTimeout)
    {
        KeInitializeTimer(&TotalTimeoutTimer);
        KeSetTimer(&TotalTimeoutTimer, WorkItemData->TotalTimeoutTime, NULL);
        ObjectsArray[ObjectCount] = &TotalTimeoutTimer;
        ObjectCount++;
    }

    /* while buffer is not fully filled */
    while (TRUE)
    {
        /* read already received bytes from buffer */
        KeAcquireSpinLock(&DeviceExtension->InputBufferLock, &Irql);
        while (!IsCircularBufferEmpty(&DeviceExtension->InputBuffer)
            && Length > 0)
        {
            PopCircularBufferEntry(&DeviceExtension->InputBuffer, &ReceivedByte);
            INFO_(SERIAL, "Reading byte from buffer: 0x%02x\n", ReceivedByte);

            Buffer[Information++] = ReceivedByte;
            Length--;
        }
        KeClearEvent(&DeviceExtension->InputBufferNotEmpty);
        KeReleaseSpinLock(&DeviceExtension->InputBufferLock, Irql);

        if (Length == 0)
        {
            INFO_(SERIAL, "All bytes read\n");
            break;
        }

        if (WorkItemData->DontWait
            && !(WorkItemData->ReadAtLeastOneByte && Information == 0))
        {
            INFO_(SERIAL, "Buffer empty. Don't wait more bytes\n");
            break;
        }

        Status = KeWaitForMultipleObjects(
            ObjectCount,
            ObjectsArray,
            WaitAny,
            Executive,
            KernelMode,
            FALSE,
            (WorkItemData->UseIntervalTimeout && Information > 0) ? &WorkItemData->IntervalTimeout : NULL,
            NULL);

        if (Status == STATUS_TIMEOUT /* interval timeout */
            || Status == STATUS_WAIT_1) /* total timeout */
        {
            TRACE_(SERIAL, "Timeout when reading bytes. Status = 0x%08lx\n", Status);
            break;
        }
    }

    /* stop total timeout timer */
    if (WorkItemData->UseTotalTimeout)
        KeCancelTimer(&TotalTimeoutTimer);

    Irp->IoStatus.Information = Information;
    if (Information == 0)
        Irp->IoStatus.Status = STATUS_TIMEOUT;
    else
        Irp->IoStatus.Status = STATUS_SUCCESS;
}

Referenced by SerialRead(), and SerialReadWorkItem().

SerialGetUserBuffer()

static PVOID SerialGetUserBuffer ( IN PIRP  Irp )

static

Definition at line 17 of file rw.c.

{
    ASSERT(Irp);

    if (Irp->MdlAddress)
        return Irp->MdlAddress;
    else
        return Irp->AssociatedIrp.SystemBuffer;
}

Referenced by ReadBytes(), SerialRead(), and SerialWrite().

SerialRead()

NTSTATUS NTAPI SerialRead	(	IN PDEVICE_OBJECT	DeviceObject,
		IN PIRP	Irp
	)

Definition at line 148 of file rw.c.

{
    PIO_STACK_LOCATION Stack;
    PSERIAL_DEVICE_EXTENSION DeviceExtension;
    ULONG Length;
    PUCHAR Buffer;
    PWORKITEM_DATA WorkItemData;
    PIO_WORKITEM WorkItem;
    NTSTATUS Status;

    TRACE_(SERIAL, "IRP_MJ_READ\n");

    Stack = IoGetCurrentIrpStackLocation(Irp);
    Length = Stack->Parameters.Read.Length;
    Buffer = SerialGetUserBuffer(Irp);
    DeviceExtension = (PSERIAL_DEVICE_EXTENSION)DeviceObject->DeviceExtension;

    if (Stack->Parameters.Read.ByteOffset.QuadPart != 0 || Buffer == NULL)
    {
        Status = STATUS_INVALID_PARAMETER;
        goto ByeBye;
    }

    if (Length == 0)
    {
        Status = STATUS_SUCCESS;
        goto ByeBye;
    }

    /* Allocate memory for parameters */
    WorkItemData = ExAllocatePoolWithTag(PagedPool, sizeof(WORKITEM_DATA), SERIAL_TAG);
    if (!WorkItemData)
    {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto ByeBye;
    }
    RtlZeroMemory(WorkItemData, sizeof(WORKITEM_DATA));
    WorkItemData->Irp = Irp;

    /* Calculate time outs */
    if (DeviceExtension->SerialTimeOuts.ReadIntervalTimeout == INFINITE &&
         DeviceExtension->SerialTimeOuts.ReadTotalTimeoutMultiplier == INFINITE &&
         DeviceExtension->SerialTimeOuts.ReadTotalTimeoutConstant > 0 &&
         DeviceExtension->SerialTimeOuts.ReadTotalTimeoutConstant < INFINITE)
    {
        /* read at least one byte, and at most bytes already received */
        WorkItemData->DontWait = TRUE;
        WorkItemData->ReadAtLeastOneByte = TRUE;
    }
    else if (DeviceExtension->SerialTimeOuts.ReadIntervalTimeout == INFINITE &&
             DeviceExtension->SerialTimeOuts.ReadTotalTimeoutConstant == 0 &&
             DeviceExtension->SerialTimeOuts.ReadTotalTimeoutMultiplier == 0)
    {
        /* read only bytes that are already in buffer */
        WorkItemData->DontWait = TRUE;
    }
    else
    {
        /* use timeouts */
        if (DeviceExtension->SerialTimeOuts.ReadIntervalTimeout != 0)
            {
                WorkItemData->UseIntervalTimeout = TRUE;
                WorkItemData->IntervalTimeout.QuadPart = DeviceExtension->SerialTimeOuts.ReadIntervalTimeout;
        }
        if (DeviceExtension->SerialTimeOuts.ReadTotalTimeoutMultiplier != 0 ||
             DeviceExtension->SerialTimeOuts.ReadTotalTimeoutConstant != 0)
        {
            ULONG TotalTimeout;
            LARGE_INTEGER SystemTime;

            WorkItemData->UseTotalTimeout = TRUE;
            TotalTimeout = DeviceExtension->SerialTimeOuts.ReadTotalTimeoutConstant +
                DeviceExtension->SerialTimeOuts.ReadTotalTimeoutMultiplier * Length;
            KeQuerySystemTime(&SystemTime);
            WorkItemData->TotalTimeoutTime.QuadPart = SystemTime.QuadPart +
                TotalTimeout * 10000;
        }
    }

    /* Pend IRP */
    WorkItem = IoAllocateWorkItem(DeviceObject);
    if (WorkItem)
    {
        WorkItemData->IoWorkItem = WorkItem;
        IoMarkIrpPending(Irp);
        IoQueueWorkItem(WorkItem, SerialReadWorkItem, DelayedWorkQueue, WorkItemData);
        return STATUS_PENDING;
    }

    /* Insufficient resources, we can't pend the Irp */
    INFO_(SERIAL, "Insufficient resources\n");
    Status = IoAcquireRemoveLock(&DeviceExtension->RemoveLock, ULongToPtr(DeviceExtension->ComPort));
    if (!NT_SUCCESS(Status))
    {
        ExFreePoolWithTag(WorkItemData, SERIAL_TAG);
        goto ByeBye;
    }
    ReadBytes(DeviceObject, Irp, WorkItemData);
    Status = Irp->IoStatus.Status;

    IoReleaseRemoveLock(&DeviceExtension->RemoveLock, ULongToPtr(DeviceExtension->ComPort));

ByeBye:
    Irp->IoStatus.Status = Status;
    IoCompleteRequest(Irp, IO_NO_INCREMENT);
    return Status;
}

SerialReadWorkItem()

static VOID NTAPI SerialReadWorkItem ( IN PDEVICE_OBJECT  DeviceObject, IN PVOID  pWorkItemData  )

static

Definition at line 127 of file rw.c.

{
    PWORKITEM_DATA WorkItemData;
    PIRP Irp;

    TRACE_(SERIAL, "SerialReadWorkItem() called\n");

    WorkItemData = (PWORKITEM_DATA)pWorkItemData;
    Irp = WorkItemData->Irp;

    ReadBytes(DeviceObject, Irp, WorkItemData);

    IoCompleteRequest(Irp, IO_NO_INCREMENT);

    IoFreeWorkItem(WorkItemData->IoWorkItem);
    ExFreePoolWithTag(pWorkItemData, SERIAL_TAG);
}

SerialWrite()

NTSTATUS NTAPI SerialWrite	(	IN PDEVICE_OBJECT	DeviceObject,
		IN PIRP	Irp
	)

Definition at line 259 of file rw.c.

{
    PIO_STACK_LOCATION Stack;
    PSERIAL_DEVICE_EXTENSION DeviceExtension;
    ULONG Length;
    ULONG_PTR Information = 0;
    PUCHAR Buffer;
    KIRQL Irql;
    NTSTATUS Status = STATUS_SUCCESS;

    TRACE_(SERIAL, "IRP_MJ_WRITE\n");

    /* FIXME: pend operation if possible */
    /* FIXME: use write timeouts */

    Stack = IoGetCurrentIrpStackLocation(Irp);
    Length = Stack->Parameters.Write.Length;
    Buffer = SerialGetUserBuffer(Irp);
    DeviceExtension = (PSERIAL_DEVICE_EXTENSION)DeviceObject->DeviceExtension;

    if (Stack->Parameters.Write.ByteOffset.QuadPart != 0 || Buffer == NULL)
    {
        Status = STATUS_INVALID_PARAMETER;
        goto ByeBye;
    }

    Status = IoAcquireRemoveLock(&DeviceExtension->RemoveLock, ULongToPtr(DeviceExtension->ComPort));
    if (!NT_SUCCESS(Status))
        goto ByeBye;

    /* push  bytes into output buffer */
    KeAcquireSpinLock(&DeviceExtension->OutputBufferLock, &Irql);
    while (Information < Length)
    {
        Status = PushCircularBufferEntry(&DeviceExtension->OutputBuffer, Buffer[Information]);
        if (!NT_SUCCESS(Status))
        {
            if (Status == STATUS_BUFFER_TOO_SMALL)
            {
                KeReleaseSpinLock(&DeviceExtension->OutputBufferLock, Irql);
                SerialSendByte(NULL, DeviceExtension, NULL, NULL);
                KeAcquireSpinLock(&DeviceExtension->OutputBufferLock, &Irql);
                continue;
            }
            else
            {
                WARN_(SERIAL, "Buffer overrun on COM%lu\n", DeviceExtension->ComPort);
                DeviceExtension->SerialPerfStats.BufferOverrunErrorCount++;
                break;
            }
        }
        Information++;
    }
    KeReleaseSpinLock(&DeviceExtension->OutputBufferLock, Irql);
    IoReleaseRemoveLock(&DeviceExtension->RemoveLock, ULongToPtr(DeviceExtension->ComPort));

    /* send bytes */
    SerialSendByte(NULL, DeviceExtension, NULL, NULL);

ByeBye:
    Irp->IoStatus.Information = Information;
    Irp->IoStatus.Status = Status;
    IoCompleteRequest(Irp, IO_NO_INCREMENT);
    return Status;
}

Variable Documentation

SerialReadWorkItem

IO_WORKITEM_ROUTINE SerialReadWorkItem

static

Definition at line 14 of file rw.c.

Referenced by SerialRead().