BOOLEAN
SerialSetupNewHandFlow(
IN PSERIAL_DEVICE_EXTENSION Extension,
IN PSERIAL_HANDFLOW NewHandFlow
)
/*++
Routine Description:
This routine adjusts the flow control based on new
control flow.
Arguments:
Extension - A pointer to the serial device extension.
NewHandFlow - A pointer to a serial handflow structure
that is to become the new setup for flow
control.
Return Value:
This routine always returns FALSE.
--*/
{
SERIAL_HANDFLOW New = *NewHandFlow;
//
// If the Extension->DeviceIsOpened is FALSE that means
// we are entering this routine in response to an open request.
// If that is so, then we always proceed with the work regardless
// of whether things have changed.
//
//
// First we take care of the DTR flow control. We only
// do work if something has changed.
//
if ((!Extension->DeviceIsOpened) ||
((Extension->HandFlow.ControlHandShake & SERIAL_DTR_MASK) !=
(New.ControlHandShake & SERIAL_DTR_MASK))) {
SerialDump(
SERFLOW,
("SERIAL: Processing DTR flow for %x\n",
Extension->Controller)
);
if (New.ControlHandShake & SERIAL_DTR_MASK) {
//
// Well we might want to set DTR.
//
// Before we do, we need to check whether we are doing
// dtr flow control. If we are then we need to check
// if then number of characters in the interrupt buffer
// exceeds the XoffLimit. If it does then we don't
// enable DTR AND we set the RXHolding to record that
// we are holding because of the dtr.
//
if ((New.ControlHandShake & SERIAL_DTR_MASK)
== SERIAL_DTR_HANDSHAKE) {
if ((Extension->BufferSize - New.XoffLimit) >
Extension->CharsInInterruptBuffer) {
//
// However if we are already holding we don't want
// to turn it back on unless we exceed the Xon
// limit.
//
if (Extension->RXHolding & SERIAL_RX_DTR) {
//
// We can assume that its DTR line is already low.
//
if (Extension->CharsInInterruptBuffer >
(ULONG)New.XonLimit) {
SerialDump(
SERFLOW,
("SERIAL: Removing DTR block on reception for %x\n",
Extension->Controller)
);
Extension->RXHolding &= ~SERIAL_RX_DTR;
SerialSetDTR(Extension);
}
} else {
SerialSetDTR(Extension);
}
} else {
SerialDump(
SERFLOW,
("SERIAL: Setting DTR block on reception for %x\n",
Extension->Controller)
);
Extension->RXHolding |= SERIAL_RX_DTR;
SerialClrDTR(Extension);
}
} else {
//
// Note that if we aren't currently doing dtr flow control then
// we MIGHT have been. So even if we aren't currently doing
// DTR flow control, we should still check if RX is holding
// because of DTR. If it is, then we should clear the holding
// of this bit.
//
if (Extension->RXHolding & SERIAL_RX_DTR) {
SerialDump(
SERFLOW,
("SERIAL: Removing dtr block of reception for %x\n",
Extension->Controller)
);
Extension->RXHolding &= ~SERIAL_RX_DTR;
}
SerialSetDTR(Extension);
}
} else {
//
// The end result here will be that DTR is cleared.
//
// We first need to check whether reception is being held
// up because of previous DTR flow control. If it is then
// we should clear that reason in the RXHolding mask.
//
if (Extension->RXHolding & SERIAL_RX_DTR) {
SerialDump(
SERFLOW,
("SERIAL: removing dtr block of reception for %x\n",
Extension->Controller)
);
Extension->RXHolding &= ~SERIAL_RX_DTR;
}
SerialClrDTR(Extension);
}
}
//
// Time to take care of the RTS Flow control.
//
// First we only do work if something has changed.
//
if ((!Extension->DeviceIsOpened) ||
((Extension->HandFlow.FlowReplace & SERIAL_RTS_MASK) !=
(New.FlowReplace & SERIAL_RTS_MASK))) {
SerialDump(
SERFLOW,
("SERIAL: Processing RTS flow\n",
Extension->Controller)
);
if ((New.FlowReplace & SERIAL_RTS_MASK) ==
SERIAL_RTS_HANDSHAKE) {
//
// Well we might want to set RTS.
//
// Before we do, we need to check whether we are doing
// rts flow control. If we are then we need to check
// if then number of characters in the interrupt buffer
// exceeds the XoffLimit. If it does then we don't
// enable RTS AND we set the RXHolding to record that
// we are holding because of the rts.
//
if ((Extension->BufferSize - New.XoffLimit) >
Extension->CharsInInterruptBuffer) {
//
// However if we are already holding we don't want
// to turn it back on unless we exceed the Xon
// limit.
//
if (Extension->RXHolding & SERIAL_RX_RTS) {
//
// We can assume that its RTS line is already low.
//
if (Extension->CharsInInterruptBuffer >
(ULONG)New.XonLimit) {
SerialDump(
SERFLOW,
("SERIAL: Removing rts block of reception for %x\n",
Extension->Controller)
);
Extension->RXHolding &= ~SERIAL_RX_RTS;
SerialSetRTS(Extension);
}
} else {
SerialSetRTS(Extension);
}
} else {
SerialDump(
SERFLOW,
("SERIAL: Setting rts block of reception for %x\n",
Extension->Controller)
);
Extension->RXHolding |= SERIAL_RX_RTS;
SerialClrRTS(Extension);
}
} else if ((New.FlowReplace & SERIAL_RTS_MASK) ==
SERIAL_RTS_CONTROL) {
//
// Note that if we aren't currently doing rts flow control then
// we MIGHT have been. So even if we aren't currently doing
// RTS flow control, we should still check if RX is holding
// because of RTS. If it is, then we should clear the holding
// of this bit.
//
if (Extension->RXHolding & SERIAL_RX_RTS) {
SerialDump(
SERFLOW,
("SERIAL: Clearing rts block of reception for %x\n",
Extension->Controller)
);
Extension->RXHolding &= ~SERIAL_RX_RTS;
}
SerialSetRTS(Extension);
} else if ((New.FlowReplace & SERIAL_RTS_MASK) ==
SERIAL_TRANSMIT_TOGGLE) {
//
// We first need to check whether reception is being held
// up because of previous RTS flow control. If it is then
// we should clear that reason in the RXHolding mask.
//
if (Extension->RXHolding & SERIAL_RX_RTS) {
SerialDump(
SERFLOW,
("SERIAL: TOGGLE Clearing rts block of reception for %x\n",
Extension->Controller)
);
Extension->RXHolding &= ~SERIAL_RX_RTS;
}
//
// We have to place the rts value into the Extension
// now so that the code that tests whether the
// rts line should be lowered will find that we
// are "still" doing transmit toggling. The code
// for lowering can be invoked later by a timer so
// it has to test whether it still needs to do its
// work.
//
Extension->HandFlow.FlowReplace &= ~SERIAL_RTS_MASK;
Extension->HandFlow.FlowReplace |= SERIAL_TRANSMIT_TOGGLE;
//
// The order of the tests is very important below.
//
// If there is a break then we should turn on the RTS.
//
// If there isn't a break but there are characters in
// the hardware, then turn on the RTS.
//
// If there are writes pending that aren't being held
// up, then turn on the RTS.
//
if ((Extension->TXHolding & SERIAL_TX_BREAK) ||
((SerialProcessLSR(Extension) & (SERIAL_LSR_THRE |
SERIAL_LSR_TEMT)) !=
(SERIAL_LSR_THRE |
SERIAL_LSR_TEMT)) ||
(Extension->CurrentWriteIrp || Extension->TransmitImmediate ||
(!IsListEmpty(&Extension->WriteQueue)) &&
(!Extension->TXHolding))) {
SerialSetRTS(Extension);
} else {
//
// This routine will check to see if it is time
// to lower the RTS because of transmit toggle
// being on. If it is ok to lower it, it will,
// if it isn't ok, it will schedule things so
// that it will get lowered later.
//
Extension->CountOfTryingToLowerRTS++;
SerialPerhapsLowerRTS(Extension);
}
} else {
//
// The end result here will be that RTS is cleared.
//
// We first need to check whether reception is being held
// up because of previous RTS flow control. If it is then
// we should clear that reason in the RXHolding mask.
//
if (Extension->RXHolding & SERIAL_RX_RTS) {
SerialDump(
SERFLOW,
("SERIAL: Clearing rts block of reception for %x\n",
Extension->Controller)
);
Extension->RXHolding &= ~SERIAL_RX_RTS;
}
SerialClrRTS(Extension);
}
}
//
// We now take care of automatic receive flow control.
// We only do work if things have changed.
//
if ((!Extension->DeviceIsOpened) ||
((Extension->HandFlow.FlowReplace & SERIAL_AUTO_RECEIVE) !=
(New.FlowReplace & SERIAL_AUTO_RECEIVE))) {
if (New.FlowReplace & SERIAL_AUTO_RECEIVE) {
//
// We wouldn't be here if it had been on before.
//
// We should check to see whether we exceed the turn
// off limits.
//
// Note that since we are following the OS/2 flow
// control rules we will never send an xon if
// when enabling xon/xoff flow control we discover that
// we could receive characters but we are held up do
// to a previous Xoff.
//
if ((Extension->BufferSize - New.XoffLimit) <=
Extension->CharsInInterruptBuffer) {
//
// Cause the Xoff to be sent.
//
Extension->RXHolding |= SERIAL_RX_XOFF;
SerialProdXonXoff(
Extension,
FALSE
);
}
} else {
//
// The app has disabled automatic receive flow control.
//
// If transmission was being held up because of
// an automatic receive Xoff, then we should
// cause an Xon to be sent.
//
if (Extension->RXHolding & SERIAL_RX_XOFF) {
Extension->RXHolding &= ~SERIAL_RX_XOFF;
//
// Cause the Xon to be sent.
//
SerialProdXonXoff(
Extension,
TRUE
);
}
}
}
//
// We now take care of automatic transmit flow control.
// We only do work if things have changed.
//
if ((!Extension->DeviceIsOpened) ||
((Extension->HandFlow.FlowReplace & SERIAL_AUTO_TRANSMIT) !=
(New.FlowReplace & SERIAL_AUTO_TRANSMIT))) {
if (New.FlowReplace & SERIAL_AUTO_TRANSMIT) {
//
// We wouldn't be here if it had been on before.
//
// BUG BUG ??? There is some belief that if autotransmit
// was just enabled, I should go look in what we
// already received, and if we find the xoff character
// then we should stop transmitting. I think this
// is an application bug. For now we just care about
// what we see in the future.
//
;
} else {
//
// The app has disabled automatic transmit flow control.
//
// If transmission was being held up because of
// an automatic transmit Xoff, then we should
// cause an Xon to be sent.
//
if (Extension->TXHolding & SERIAL_TX_XOFF) {
Extension->TXHolding &= ~SERIAL_TX_XOFF;
//
// Cause the Xon to be sent.
//
SerialProdXonXoff(
Extension,
TRUE
);
}
}
}
//
// At this point we can simply make sure that entire
// handflow structure in the extension is updated.
//
Extension->HandFlow = New;
return FALSE;
}
VOID
SerialFileCloseWorker(
IN WDFDEVICE Device
)
{
ULONG flushCount;
//
// This "timer value" is used to wait 10 character times
// after the hardware is empty before we actually "run down"
// all of the flow control/break junk.
//
LARGE_INTEGER tenCharDelay;
//
// Holds a character time.
//
LARGE_INTEGER charTime;
PSERIAL_DEVICE_EXTENSION extension = SerialGetDeviceExtension(Device);
PSERIAL_INTERRUPT_CONTEXT interruptContext = SerialGetInterruptContext(extension->WdfInterrupt);
SerialDbgPrintEx(TRACE_LEVEL_INFORMATION, DBG_CREATE_CLOSE, "In SerialEvtFileClose %wZ\n",
&extension->DeviceName);
//
// Acquire the interrupt state lock.
//
WdfWaitLockAcquire(interruptContext->InterruptStateLock, NULL);
//
// If the Interrupts are connected, then the hardware state has to be
// cleaned up now. Note that the EvtFileClose callback gets called for
// an open file object even though the interrupts have been disabled
// possibly due to a Surprise Remove PNP event. In such a case, the
// Interrupt object should not be used.
//
if (interruptContext->IsInterruptConnected) {
charTime.QuadPart = -SerialGetCharTime(extension).QuadPart;
//
// Do this now so that if the isr gets called it won't do anything
// to cause more chars to get sent. We want to run down the hardware.
//
SetDeviceIsOpened(extension, FALSE, FALSE);
//
// Synchronize with the isr to turn off break if it
// is already on.
//
WdfInterruptSynchronize(
extension->WdfInterrupt,
SerialTurnOffBreak,
extension
);
//
// Wait a reasonable amount of time (20 * fifodepth) until all characters
// have been emptied out of the hardware.
//
for (flushCount = (20 * 16); flushCount != 0; flushCount--) {
if ((READ_LINE_STATUS(extension, extension->Controller) &
(SERIAL_LSR_THRE | SERIAL_LSR_TEMT)) !=
(SERIAL_LSR_THRE | SERIAL_LSR_TEMT)) {
KeDelayExecutionThread(KernelMode, FALSE, &charTime);
} else {
break;
}
}
if (flushCount == 0) {
SerialMarkHardwareBroken(extension);
}
//
// Synchronize with the ISR to let it know that interrupts are
// no longer important.
//
WdfInterruptSynchronize(
extension->WdfInterrupt,
SerialMarkClose,
extension
);
//
// If the driver has automatically transmitted an Xoff in
// the context of automatic receive flow control then we
// should transmit an Xon.
//
if (extension->RXHolding & SERIAL_RX_XOFF) {
//
// Loop until the holding register is empty.
//
while (!(READ_LINE_STATUS(extension, extension->Controller) &
SERIAL_LSR_THRE)) {
KeDelayExecutionThread(
KernelMode,
FALSE,
&charTime
);
}
WRITE_TRANSMIT_HOLDING(extension,
extension->Controller,
extension->SpecialChars.XonChar
);
//
// Wait a reasonable amount of time for the characters
// to be emptied out of the hardware.
//
for (flushCount = (20 * 16); flushCount != 0; flushCount--) {
if ((READ_LINE_STATUS(extension, extension->Controller) &
(SERIAL_LSR_THRE | SERIAL_LSR_TEMT)) !=
(SERIAL_LSR_THRE | SERIAL_LSR_TEMT)) {
KeDelayExecutionThread(KernelMode, FALSE, &charTime);
} else {
break;
}
}
if (flushCount == 0) {
SerialMarkHardwareBroken(extension);
}
}
//
// The hardware is empty. Delay 10 character times before
// shut down all the flow control.
//
tenCharDelay.QuadPart = charTime.QuadPart * 10;
KeDelayExecutionThread(
KernelMode,
TRUE,
&tenCharDelay
);
#pragma prefast(suppress: __WARNING_INFERRED_IRQ_TOO_LOW, "This warning is because we are calling interrupt synchronize routine directly.")
SerialClrDTR(extension->WdfInterrupt, extension);
//
// We have to be very careful how we clear the RTS line.
// Transmit toggling might have been on at some point.
//
// We know that there is nothing left that could start
// out the "polling" execution path. We need to
// check the counter that indicates that the execution
// path is active. If it is then we loop delaying one
// character time. After each delay we check to see if
// the counter has gone to zero. When it has we know that
// the execution path should be just about finished. We
// make sure that we still aren't in the routine that
// synchronized execution with the ISR by synchronizing
// ourselve with the ISR.
//
if (extension->CountOfTryingToLowerRTS) {
do {
#pragma prefast(suppress: __WARNING_INFERRED_IRQ_TOO_HIGH, "This warning is due to suppressing the previous one.")
KeDelayExecutionThread(
KernelMode,
FALSE,
&charTime
);
} while (extension->CountOfTryingToLowerRTS);
//
// The execution path should no longer exist that
// is trying to push down the RTS. Well just
// make sure it's down by falling through to
// code that forces it down.
//
}
#pragma prefast(suppress: __WARNING_INFERRED_IRQ_TOO_LOW, "This warning is because we are calling interrupt synchronize routine directly.")
SerialClrRTS(extension->WdfInterrupt, extension);
//
// Clean out the holding reasons (since we are closed).
//
extension->RXHolding = 0;
extension->TXHolding = 0;
//
// Mark device as not busy for WMI
//
extension->WmiCommData.IsBusy = FALSE;
}
//
// Release the Interrupt state lock.
//
WdfWaitLockRelease(interruptContext->InterruptStateLock);
//
// All is done. The port has been disabled from interrupting
// so there is no point in keeping the memory around.
//
extension->BufferSize = 0;
if (extension->InterruptReadBuffer != NULL) {
ExFreePool(extension->InterruptReadBuffer);
}
extension->InterruptReadBuffer = NULL;
//
// Make sure the wake is disabled.
//
ASSERT(!extension->IsWakeEnabled);
SerialDrainTimersAndDpcs(extension);
SerialDbgPrintEx(TRACE_LEVEL_VERBOSE, DBG_CREATE_CLOSE, "DPC's drained:\n");
//
// It's fine for the device to be powered off if there are no open handles.
//
WdfDeviceResumeIdle(Device);
//
// It's okay to allow the device to be stopped or removed.
//
// Note to anyone copying this sample as a starting point:
//
// This works in this driver simply because this driver supports exactly
// one open handle at a time. If it supported more, then it would need
// counting logic to determine when all the reasons for failing Stop/Remove
// were gone.
//
WdfDeviceSetStaticStopRemove(Device, TRUE);
return;
}
BOOLEAN
SerialPerhapsLowerRTS(
IN PVOID Context
)
/*++
Routine Description:
This routine checks that the software reasons for lowering
the RTS lines are present. If so, it will then cause the
line status register to be read (and any needed processing
implied by the status register to be done), and if the
shift register is empty it will lower the line. If the
shift register isn't empty, this routine will queue off
a dpc that will start a timer, that will basically call
us back to try again.
NOTE: This routine assumes that it is called at interrupt
level.
Arguments:
Context - Really a pointer to the device extension.
Return Value:
Always FALSE.
--*/
{
PSERIAL_DEVICE_EXTENSION Extension = Context;
//
// We first need to test if we are actually still doing
// transmit toggle flow control. If we aren't then
// we have no reason to try be here.
//
if ((Extension->HandFlow.FlowReplace & SERIAL_RTS_MASK) ==
SERIAL_TRANSMIT_TOGGLE) {
//
// The order of the tests is very important below.
//
// If there is a break then we should leave on the RTS,
// because when the break is turned off, it will submit
// the code to shut down the RTS.
//
// If there are writes pending that aren't being held
// up, then leave on the RTS, because the end of the write
// code will cause this code to be reinvoked. If the writes
// are being held up, its ok to lower the RTS because the
// upon trying to write the first character after transmission
// is restarted, we will raise the RTS line.
//
if ((Extension->TXHolding & SERIAL_TX_BREAK) ||
(Extension->CurrentWriteIrp || Extension->TransmitImmediate ||
(!IsListEmpty(&Extension->WriteQueue)) &&
(!Extension->TXHolding))) {
NOTHING;
} else {
//
// Looks good so far. Call the line status check and processing
// code, it will return the "current" line status value. If
// the holding and shift register are clear, lower the RTS line,
// if they aren't clear, queue of a dpc that will cause a timer
// to reinvoke us later. We do this code here because no one
// but this routine cares about the characters in the hardware,
// so no routine by this routine will bother invoking to test
// if the hardware is empty.
//
if ((SerialProcessLSR(Extension) &
(SERIAL_LSR_THRE | SERIAL_LSR_TEMT)) !=
(SERIAL_LSR_THRE | SERIAL_LSR_TEMT)) {
//
// Well it's not empty, try again later.
//
KeInsertQueueDpc(
&Extension->StartTimerLowerRTSDpc,
NULL,
NULL
)?Extension->CountOfTryingToLowerRTS++:0;
} else {
//
// Nothing in the hardware, Lower the RTS.
//
SerialClrRTS(Extension);
}
}
}
//
// We decement the counter to indicate that we've reached
// the end of the execution path that is trying to push
// down the RTS line.
//
Extension->CountOfTryingToLowerRTS--;
return FALSE;
}
VOID
SerialPutChar(
IN PSERIAL_DEVICE_EXTENSION Extension,
IN UCHAR CharToPut
)
/*++
Routine Description:
This routine, which only runs at device level, takes care of
placing a character into the typeahead (receive) buffer.
Arguments:
Extension - The serial device extension.
Return Value:
None.
--*/
{
PREQUEST_CONTEXT reqContext = NULL;
//
// If we have dsr sensitivity enabled then
// we need to check the modem status register
// to see if it has changed.
//
if (Extension->HandFlow.ControlHandShake &
SERIAL_DSR_SENSITIVITY) {
SerialHandleModemUpdate(
Extension,
FALSE
);
if (Extension->RXHolding & SERIAL_RX_DSR) {
//
// We simply act as if we haven't
// seen the character if we have dsr
// sensitivity and the dsr line is low.
//
return;
}
}
//
// If the xoff counter is non-zero then decrement it.
// If the counter then goes to zero, complete that request.
//
if (Extension->CountSinceXoff) {
Extension->CountSinceXoff--;
if (!Extension->CountSinceXoff) {
reqContext = SerialGetRequestContext(Extension->CurrentXoffRequest);
reqContext->Status = STATUS_SUCCESS;
reqContext->Information = 0;
SerialInsertQueueDpc(
Extension->XoffCountCompleteDpc
);
}
}
//
// Check to see if we are copying into the
// users buffer or into the interrupt buffer.
//
// If we are copying into the user buffer
// then we know there is always room for one more.
// (We know this because if there wasn't room
// then that read would have completed and we
// would be using the interrupt buffer.)
//
// If we are copying into the interrupt buffer
// then we will need to check if we have enough
// room.
//
if (Extension->ReadBufferBase !=
Extension->InterruptReadBuffer) {
//
// Increment the following value so
// that the interval timer (if one exists
// for this read) can know that a character
// has been read.
//
Extension->ReadByIsr++;
//
// We are in the user buffer. Place the
// character into the buffer. See if the
// read is complete.
//
*Extension->CurrentCharSlot = CharToPut;
if (Extension->CurrentCharSlot ==
Extension->LastCharSlot) {
//
// We've filled up the users buffer.
// Switch back to the interrupt buffer
// and send off a DPC to Complete the read.
//
// It is inherent that when we were using
// a user buffer that the interrupt buffer
// was empty.
//
Extension->ReadBufferBase =
Extension->InterruptReadBuffer;
Extension->CurrentCharSlot =
Extension->InterruptReadBuffer;
Extension->FirstReadableChar =
Extension->InterruptReadBuffer;
Extension->LastCharSlot =
Extension->InterruptReadBuffer +
(Extension->BufferSize - 1);
Extension->CharsInInterruptBuffer = 0;
reqContext = SerialGetRequestContext(Extension->CurrentReadRequest);
reqContext->Information = reqContext->Length;
SerialInsertQueueDpc(
Extension->CompleteReadDpc
);
} else {
//
// Not done with the users read.
//
Extension->CurrentCharSlot++;
}
} else {
//
// We need to see if we reached our flow
// control threshold. If we have then
// we turn on whatever flow control the
// owner has specified. If no flow
// control was specified, well..., we keep
// trying to receive characters and hope that
// we have enough room. Note that no matter
// what flow control protocol we are using, it
// will not prevent us from reading whatever
// characters are available.
//
if ((Extension->HandFlow.ControlHandShake
& SERIAL_DTR_MASK) ==
SERIAL_DTR_HANDSHAKE) {
//
// If we are already doing a
// dtr hold then we don't have
// to do anything else.
//
if (!(Extension->RXHolding &
SERIAL_RX_DTR)) {
if ((Extension->BufferSize -
Extension->HandFlow.XoffLimit)
<= (Extension->CharsInInterruptBuffer+1)) {
Extension->RXHolding |= SERIAL_RX_DTR;
SerialClrDTR(Extension->WdfInterrupt, Extension);
}
}
}
if ((Extension->HandFlow.FlowReplace
& SERIAL_RTS_MASK) ==
SERIAL_RTS_HANDSHAKE) {
//
// If we are already doing a
// rts hold then we don't have
// to do anything else.
//
if (!(Extension->RXHolding &
SERIAL_RX_RTS)) {
if ((Extension->BufferSize -
Extension->HandFlow.XoffLimit)
<= (Extension->CharsInInterruptBuffer+1)) {
Extension->RXHolding |= SERIAL_RX_RTS;
SerialClrRTS(Extension->WdfInterrupt, Extension);
}
}
}
if (Extension->HandFlow.FlowReplace &
SERIAL_AUTO_RECEIVE) {
//
// If we are already doing a
// xoff hold then we don't have
// to do anything else.
//
if (!(Extension->RXHolding &
SERIAL_RX_XOFF)) {
if ((Extension->BufferSize -
Extension->HandFlow.XoffLimit)
<= (Extension->CharsInInterruptBuffer+1)) {
Extension->RXHolding |= SERIAL_RX_XOFF;
//
// If necessary cause an
// off to be sent.
//
SerialProdXonXoff(
Extension,
FALSE
);
}
}
}
if (Extension->CharsInInterruptBuffer <
Extension->BufferSize) {
*Extension->CurrentCharSlot = CharToPut;
Extension->CharsInInterruptBuffer++;
//
// If we've become 80% full on this character
// and this is an interesting event, note it.
//
if (Extension->CharsInInterruptBuffer ==
Extension->BufferSizePt8) {
if (Extension->IsrWaitMask &
SERIAL_EV_RX80FULL) {
Extension->HistoryMask |= SERIAL_EV_RX80FULL;
if (Extension->IrpMaskLocation) {
*Extension->IrpMaskLocation =
Extension->HistoryMask;
Extension->IrpMaskLocation = NULL;
Extension->HistoryMask = 0;
reqContext = SerialGetRequestContext(Extension->CurrentWaitRequest);
reqContext->Information = sizeof(ULONG);
SerialInsertQueueDpc(
Extension->CommWaitDpc
);
}
}
}
//
// Point to the next available space
// for a received character. Make sure
// that we wrap around to the beginning
// of the buffer if this last character
// received was placed at the last slot
// in the buffer.
//
if (Extension->CurrentCharSlot ==
Extension->LastCharSlot) {
Extension->CurrentCharSlot =
Extension->InterruptReadBuffer;
} else {
Extension->CurrentCharSlot++;
}
} else {
//
// We have a new character but no room for it.
//
Extension->PerfStats.BufferOverrunErrorCount++;
Extension->WmiPerfData.BufferOverrunErrorCount++;
Extension->ErrorWord |= SERIAL_ERROR_QUEUEOVERRUN;
if (Extension->HandFlow.FlowReplace &
SERIAL_ERROR_CHAR) {
//
// Place the error character into the last
// valid place for a character. Be careful!,
// that place might not be the previous location!
//
if (Extension->CurrentCharSlot ==
Extension->InterruptReadBuffer) {
*(Extension->InterruptReadBuffer+
(Extension->BufferSize-1)) =
Extension->SpecialChars.ErrorChar;
} else {
*(Extension->CurrentCharSlot-1) =
Extension->SpecialChars.ErrorChar;
}
}
//
// If the application has requested it, abort all reads
// and writes on an error.
//
if (Extension->HandFlow.ControlHandShake &
SERIAL_ERROR_ABORT) {
SerialInsertQueueDpc(
Extension->CommErrorDpc
);
}
}
}
}
