void com_putchar(char ch)
{
if (ch == '\n') {
com_putchar('\r');
}
while ((READ_PORT_UCHAR (pv(SER_LSR(COM_BASE))) & SR_LSR_TBE) == 0);
WRITE_PORT_UCHAR(pv(SER_THR(COM_BASE)), ch);
}
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);
}
