BOOLEAN
SerialSetBaud(
IN PVOID Context
)
/*++
Routine Description:
This routine is used to set the buad rate of the device.
Arguments:
Context - Pointer to a structure that contains a pointer to
the device extension and what should be the current
baud rate.
Return Value:
This routine always returns FALSE.
--*/
{
PSERIAL_DEVICE_EXTENSION Extension = ((PSERIAL_IOCTL_SYNC)Context)->Extension;
USHORT Appropriate = (USHORT)(((PSERIAL_IOCTL_SYNC)Context)->Data);
WRITE_DIVISOR_LATCH(
Extension->Controller,
Appropriate
);
return FALSE;
}
///////////////////////////////////////////////////////////////////////////////
// Does : Initializes the device.
// Parameters : port - Port of a 8250
// baudrate - Baudrate to init 8250 to
// dataBits - Number of data bits (5..8)
// stopBits - Number of stop bits (1..2)
// parity - 0 == NONE, 1 == ODD, 2 == EVEN
// Returns : Status of the operation.
// Postcondition : Ready to start interrupt processing when returning
// STATUS_SUCCESS.
///////////////////////////////////////////////////////////////////////////////
NTSTATUS Hw8250Init(PUCHAR port, ULONG baudRate, ULONG dataBits,
ULONG stopBits, ULONG parity)
{
NTSTATUS result = STATUS_SUCCESS;
ULONG divisor;
UCHAR dataFormat;
// disable all interrupts
WRITE_INTERRUPT_ENABLE(port, 0x00);
// set up baudrate
divisor = Hw8550InternalGetDivisor(baudRate);
WRITE_LINE_CONTROL(port, LCR_DLAB);
WRITE_DIVISOR_LATCH(port, divisor);
// set up data bits (defaults to 8 data bits)
switch(dataBits) {
case 5:
dataFormat = LCR_DATA_5;
break;
case 6:
dataFormat = LCR_DATA_6;
break;
case 7:
dataFormat = LCR_DATA_7;
break;
case 8:
default:
dataFormat = LCR_DATA_8;
break;
}
// set up stop bits (defaults to 1 stop bit)
if(stopBits == 2) {
dataFormat |= LCR_STOP_2;
}
else {
dataFormat |= LCR_STOP_1;
}
// set up parity (defaults to none)
switch(parity) {
case 4:
dataFormat |= LCR_PARITY_SPACE;
break;
case 3:
dataFormat |= LCR_PARITY_MARK;
break;
case 2:
dataFormat |= LCR_PARITY_EVEN;
break;
case 1:
dataFormat |= LCR_PARITY_ODD;
break;
case 0:
default:
dataFormat |= LCR_PARITY_NONE;
break;
}
WRITE_LINE_CONTROL(port, dataFormat);
WRITE_MODEM_CONTROL(port, MCR_GPO1 | MCR_RTS | MCR_DTR);
return result;
} // end Hw8250Init
//
// Internal Function: UartCtlSetBaudRate
//
VOID
UartCtlSetBaudRate(
_In_ WDFDEVICE Device,
_In_ WDFREQUEST Request,
_In_ size_t OutputBufferLength,
_In_ size_t InputBufferLength
)
{
NTSTATUS status = STATUS_UNSUCCESSFUL;
PUART_DEVICE_EXTENSION pDevExt = UartGetDeviceExtension(Device);
PSERIAL_BAUD_RATE pBaudRate = NULL;
USHORT DivisorLatchRegs = 0;
UNREFERENCED_PARAMETER(OutputBufferLength);
UNREFERENCED_PARAMETER(InputBufferLength);
FuncEntry(TRACE_FLAG_CONTROL);
status = WdfRequestRetrieveInputBuffer(Request,
sizeof(SERIAL_BAUD_RATE),
(PVOID*)(& pBaudRate),
NULL);
if (!NT_SUCCESS(status))
{
TraceMessage(
TRACE_LEVEL_ERROR,
TRACE_FLAG_CONTROL,
"Failed to retrieve input buffer for WDFREQUEST %p - "
"%!STATUS!",
Request,
status);
}
if (NT_SUCCESS(status))
{
status = UartRegConvertAndValidateBaud(
pBaudRate->BaudRate,
&DivisorLatchRegs);
if (!NT_SUCCESS(status))
{
TraceMessage(
TRACE_LEVEL_ERROR,
TRACE_FLAG_CONTROL,
"Failed to convert and validate baudrate %lu - "
"%!STATUS!",
pBaudRate->BaudRate,
status);
}
}
if (NT_SUCCESS(status))
{
// Acquires the interrupt lock and writes the Divisor Latch.
WdfInterruptAcquireLock(pDevExt->WdfInterrupt);
pDevExt->CurrentBaud = pBaudRate->BaudRate;
WRITE_DIVISOR_LATCH(pDevExt, pDevExt->Controller, DivisorLatchRegs);
WdfInterruptReleaseLock(pDevExt->WdfInterrupt);
}
TraceMessage(TRACE_LEVEL_INFORMATION,
TRACE_FLAG_CONTROL,
"WdfRequestComplete( %!HANDLE! => %!STATUS! )",
Request,
status);
WdfRequestComplete(Request, status);
FuncExit(TRACE_FLAG_CONTROL);
}
