VOID NTAPI
SerialSendByte(
IN PKDPC Dpc,
IN PVOID pDeviceExtension, // real type PSERIAL_DEVICE_EXTENSION
IN PVOID Unused1,
IN PVOID Unused2)
{
PSERIAL_DEVICE_EXTENSION DeviceExtension;
PUCHAR ComPortBase;
UCHAR Byte;
KIRQL Irql;
UCHAR IER;
NTSTATUS Status;
DeviceExtension = (PSERIAL_DEVICE_EXTENSION)pDeviceExtension;
ComPortBase = ULongToPtr(DeviceExtension->BaseAddress);
KeAcquireSpinLock(&DeviceExtension->OutputBufferLock, &Irql);
while (!IsCircularBufferEmpty(&DeviceExtension->OutputBuffer)
&& READ_PORT_UCHAR(SER_LSR(ComPortBase)) & SR_LSR_THR_EMPTY)
{
Status = PopCircularBufferEntry(&DeviceExtension->OutputBuffer, &Byte);
if (!NT_SUCCESS(Status))
break;
WRITE_PORT_UCHAR(SER_THR(ComPortBase), Byte);
INFO_(SERIAL, "Byte sent to COM%lu: 0x%02x\n",
DeviceExtension->ComPort, Byte);
DeviceExtension->SerialPerfStats.TransmittedCount++;
}
if (!IsCircularBufferEmpty(&DeviceExtension->OutputBuffer))
{
/* allow new interrupts */
IER = READ_PORT_UCHAR(SER_IER(ComPortBase));
WRITE_PORT_UCHAR(SER_IER(ComPortBase), IER | SR_IER_THR_EMPTY);
}
KeReleaseSpinLock(&DeviceExtension->OutputBufferLock, Irql);
}
static VOID
ReadBytes(
IN PDEVICE_OBJECT DeviceObject,
IN PIRP Irp,
PWORKITEM_DATA WorkItemData)
{
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 (Length > 0)
{
/* 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 (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;
}