VOID NTAPI
SerialReceiveByte(
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->InputBufferLock, &Irql);
while (READ_PORT_UCHAR(SER_LSR(ComPortBase)) & SR_LSR_DATA_RECEIVED)
{
Byte = READ_PORT_UCHAR(SER_RBR(ComPortBase));
INFO_(SERIAL, "Byte received on COM%lu: 0x%02x\n",
DeviceExtension->ComPort, Byte);
Status = PushCircularBufferEntry(&DeviceExtension->InputBuffer, Byte);
if (NT_SUCCESS(Status))
DeviceExtension->SerialPerfStats.ReceivedCount++;
else
DeviceExtension->SerialPerfStats.BufferOverrunErrorCount++;
}
KeSetEvent(&DeviceExtension->InputBufferNotEmpty, 0, FALSE);
KeReleaseSpinLock(&DeviceExtension->InputBufferLock, Irql);
/* allow new interrupts */
IER = READ_PORT_UCHAR(SER_IER(ComPortBase));
WRITE_PORT_UCHAR(SER_IER(ComPortBase), IER | SR_IER_DATA_RECEIVED);
}
NTSTATUS NTAPI
SerialWrite(
IN PDEVICE_OBJECT DeviceObject,
IN PIRP Irp)
{
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;
}
