quakeforge/nq/source/net_comx.c

/*
	net_comx.c

	@description@

	Copyright (C) 1996-1997  Id Software, Inc.

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

	See the GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id$
*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <dos.h>
#include <dpmi.h>

#define NUM_COM_PORTS	2

#define ERR_TTY_LINE_STATUS		-1
#define ERR_TTY_MODEM_STATUS	-2
#define ERR_TTY_NODATA			-3

#define QUEUESIZE	8192
#define QUEUEMASK	(QUEUESIZE - 1)

typedef struct {
	volatile int head;
	volatile int tail;
	volatile byte data[QUEUESIZE];
} queue;

#define FULL(q)			(q.head == ((q.tail-1) & QUEUEMASK))
#define EMPTY(q)		(q.tail == q.head)
#define ENQUEUE(q,b)	(q.data[q.head] = b, q.head = (q.head + 1) & QUEUEMASK)
#define DEQUEUE(q,b)	(b = q.data[q.tail], q.tail = (q.tail + 1) & QUEUEMASK)

extern int  m_return_state;
extern int  m_state;
extern qboolean m_return_onerror;
extern char m_return_reason[32];

// 8250, 16550 definitions
#define TRANSMIT_HOLDING_REGISTER            0x00
#define RECEIVE_BUFFER_REGISTER              0x00
#define INTERRUPT_ENABLE_REGISTER            0x01
#define   IER_RX_DATA_READY                  0x01
#define   IER_TX_HOLDING_REGISTER_EMPTY      0x02
#define   IER_LINE_STATUS                    0x04
#define   IER_MODEM_STATUS                   0x08
#define INTERRUPT_ID_REGISTER                0x02
#define   IIR_MODEM_STATUS_INTERRUPT         0x00
#define   IIR_TX_HOLDING_REGISTER_INTERRUPT  0x02
#define   IIR_RX_DATA_READY_INTERRUPT        0x04
#define   IIR_LINE_STATUS_INTERRUPT          0x06
#define   IIR_FIFO_TIMEOUT                   0x0c
#define   IIR_FIFO_ENABLED                   0xc0
#define FIFO_CONTROL_REGISTER                0x02
#define   FCR_FIFO_ENABLE                    0x01
#define   FCR_RCVR_FIFO_RESET                0x02
#define   FCR_XMIT_FIFO_RESET                0x04
#define   FCR_TRIGGER_01                     0x00
#define   FCR_TRIGGER_04                     0x40
#define   FCR_TRIGGER_08                     0x80
#define   FCR_TRIGGER_16                     0xc0
#define LINE_CONTROL_REGISTER                0x03
#define   LCR_DATA_BITS_5                    0x00
#define   LCR_DATA_BITS_6                    0x01
#define   LCR_DATA_BITS_7                    0x02
#define   LCR_DATA_BITS_8                    0x03
#define   LCR_STOP_BITS_1                    0x00
#define   LCR_STOP_BITS_2                    0x04
#define   LCR_PARITY_NONE                    0x00
#define   LCR_PARITY_ODD                     0x08
#define   LCR_PARITY_EVEN                    0x18
#define   LCR_PARITY_MARK                    0x28
#define   LCR_PARITY_SPACE                   0x38
#define   LCR_SET_BREAK                      0x40
#define   LCR_DLAB                           0x80
#define MODEM_CONTROL_REGISTER               0x04
#define   MCR_DTR                            0x01
#define   MCR_RTS                            0x02
#define   MCR_OUT1                           0x04
#define   MCR_OUT2                           0x08
#define   MCR_LOOPBACK                       0x10
#define LINE_STATUS_REGISTER                 0x05
#define   LSR_DATA_READY                     0x01
#define   LSR_OVERRUN_ERROR                  0x02
#define   LSR_PARITY_ERROR                   0x04
#define   LSR_FRAMING_ERROR                  0x08
#define   LSR_BREAK_DETECT                   0x10
#define   LSR_TRANSMITTER_BUFFER_EMPTY       0x20
#define   LSR_TRANSMITTER_EMPTY              0x40
#define   LSR_FIFO_DIRTY                     0x80
#define MODEM_STATUS_REGISTER                0x06
#define   MSR_DELTA_CTS                      0x01
#define   MSR_DELTA_DSR                      0x02
#define   MSR_DELTA_RI                       0x04
#define   MSR_DELTA_CD                       0x08
#define   MSR_CTS                            0x10
#define   MSR_DSR                            0x20
#define   MSR_RI                             0x40
#define   MSR_CD                             0x80
#define DIVISOR_LATCH_LOW                    0x00
#define DIVISOR_LATCH_HIGH                   0x01

#define MODEM_STATUS_MASK	(MSR_CTS | MSR_DSR | MSR_CD)

#define UART_AUTO	0
#define UART_8250	1
#define UART_16550	2

static int  ISA_uarts[] = { 0x3f8, 0x2f8, 0x3e8, 0x2e8 };
static int  ISA_IRQs[] = { 4, 3, 4, 3 };

typedef struct ComPort_s {
	struct ComPort_s *next;
	_go32_dpmi_seginfo protectedModeInfo;
	_go32_dpmi_seginfo protectedModeSaveInfo;
	int         uart;
	volatile byte modemStatus;
	byte        modemStatusIgnore;
	byte        lineStatus;
	byte        bufferUsed;
	qboolean    enabled;
	volatile qboolean statusUpdated;
	qboolean    useModem;
	qboolean    modemInitialized;
	qboolean    modemRang;
	qboolean    modemConnected;
	queue       inputQueue;
	queue       outputQueue;
	char        clear[16];
	char        startup[32];
	char        shutdown[16];
	char        buffer[128];
	PollProcedure poll;
	double      timestamp;
	byte        uartType;
	byte        irq;
	byte        baudBits;
	byte        lineControl;
	byte        portNumber;
	char        dialType;
	char        name[4];
} ComPort;

ComPort    *portList = NULL;
ComPort    *handleToPort[NUM_COM_PORTS];

static int  Modem_Command (ComPort * p, char *commandString);
static char *Modem_Response (ComPort * p);
static void Modem_Hangup (ComPort * p);

int         TTY_Init (void);
void        TTY_Shutdown (void);
int         TTY_Open (int serialPortNumber);
void        TTY_Close (int handle);
int         TTY_ReadByte (int handle);
int         TTY_WriteByte (int handle, byte data);
void        TTY_Flush (int handle);
int         TTY_Connect (int handle, char *host);
void        TTY_Disconnect (int handle);
qboolean    TTY_CheckForConnection (int handle);
qboolean    TTY_IsEnabled (int serialPortNumber);
qboolean    TTY_IsModem (int serialPortNumber);
qboolean    TTY_OutputQueueIsEmpty (int handle);

static void
ISR_8250 (ComPort * p)
{
	byte        source = 0;
	byte        b;

	disable ();

	while ((source = inportb (p->uart + INTERRUPT_ID_REGISTER) & 0x07) != 1) {
		switch (source) {
			case IIR_RX_DATA_READY_INTERRUPT:
			b = inportb (p->uart + RECEIVE_BUFFER_REGISTER);
			if (!FULL (p->inputQueue)) {
				ENQUEUE (p->inputQueue, b);
			} else {
				p->lineStatus |= LSR_OVERRUN_ERROR;
				p->statusUpdated = true;
			}
			break;

			case IIR_TX_HOLDING_REGISTER_INTERRUPT:
			if (!EMPTY (p->outputQueue)) {
				DEQUEUE (p->outputQueue, b);
				outportb (p->uart + TRANSMIT_HOLDING_REGISTER, b);
			}
			break;

			case IIR_MODEM_STATUS_INTERRUPT:
			p->modemStatus =
				(inportb (p->uart + MODEM_STATUS_REGISTER) & MODEM_STATUS_MASK)
				| p->modemStatusIgnore;
			p->statusUpdated = true;
			break;

			case IIR_LINE_STATUS_INTERRUPT:
			p->lineStatus = inportb (p->uart + LINE_STATUS_REGISTER);
			p->statusUpdated = true;
			break;
		}
		source = inportb (p->uart + INTERRUPT_ID_REGISTER) & 0x07;
	}
	outportb (0x20, 0x20);
}

static void
COM1_ISR_8250 (void)
{
	ISR_8250 (handleToPort[0]);
}

static void
COM2_ISR_8250 (void)
{
	ISR_8250 (handleToPort[1]);
}



static void
ISR_16550 (ComPort * p)
{
	int         count;
	byte        source;
	byte        b;

	disable ();
	while ((source = inportb (p->uart + INTERRUPT_ID_REGISTER) & 0x07) != 1) {
		switch (source) {
			case IIR_RX_DATA_READY_INTERRUPT:
			do {
				b = inportb (p->uart + RECEIVE_BUFFER_REGISTER);
				if (!FULL (p->inputQueue)) {
					ENQUEUE (p->inputQueue, b);
				} else {
					p->lineStatus |= LSR_OVERRUN_ERROR;
					p->statusUpdated = true;
				}
			} while (inportb (p->uart + LINE_STATUS_REGISTER) & LSR_DATA_READY);
			break;

			case IIR_TX_HOLDING_REGISTER_INTERRUPT:
			count = 16;
			while ((!EMPTY (p->outputQueue)) && count--) {
				DEQUEUE (p->outputQueue, b);
				outportb (p->uart + TRANSMIT_HOLDING_REGISTER, b);
			}
			break;

			case IIR_MODEM_STATUS_INTERRUPT:
			p->modemStatus =
				(inportb (p->uart + MODEM_STATUS_REGISTER) & MODEM_STATUS_MASK)
				| p->modemStatusIgnore;
			p->statusUpdated = true;
			break;

			case IIR_LINE_STATUS_INTERRUPT:
			p->lineStatus = inportb (p->uart + LINE_STATUS_REGISTER);
			p->statusUpdated = true;
			break;
		}
		source = inportb (p->uart + INTERRUPT_ID_REGISTER) & 0x07;
	}

	// check for lost IIR_TX_HOLDING_REGISTER_INTERRUPT on 16550a!
	if (inportb (p->uart + LINE_STATUS_REGISTER) & LSR_TRANSMITTER_EMPTY) {
		count = 16;
		while ((!EMPTY (p->outputQueue)) && count--) {
			DEQUEUE (p->outputQueue, b);
			outportb (p->uart + TRANSMIT_HOLDING_REGISTER, b);
		}
	}

	outportb (0x20, 0x20);
}

static void
COM1_ISR_16550 (void)
{
	ISR_16550 (handleToPort[0]);
}

static void
COM2_ISR_16550 (void)
{
	ISR_16550 (handleToPort[1]);
}


void
TTY_GetComPortConfig (int portNumber, int *port, int *irq, int *baud,
					  qboolean *useModem)
{
	ComPort    *p;

	p = handleToPort[portNumber];
	*port = p->uart;
	*irq = p->irq;
	*baud = 115200 / p->baudBits;
	*useModem = p->useModem;
}

void
TTY_SetComPortConfig (int portNumber, int port, int irq, int baud,
					  qboolean useModem)
{
	ComPort    *p;
	float       temp;

	if (useModem) {
		if (baud == 14400)
			baud = 19200;
		if (baud == 28800)
			baud = 38400;
	}

	p = handleToPort[portNumber];
	p->uart = port;
	p->irq = irq;
	p->baudBits = 115200 / baud;
	p->useModem = useModem;

	if (useModem)
		temp = 1.0;
	else
		temp = 0.0;

	Cvar_SetValue ("_config_com_port", (float) port);
	Cvar_SetValue ("_config_com_irq", (float) irq);
	Cvar_SetValue ("_config_com_baud", (float) baud);
	Cvar_SetValue ("_config_com_modem", temp);
}

void
TTY_GetModemConfig (int portNumber, char *dialType, char *clear, char *init,
					char *hangup)
{
	ComPort    *p;

	p = handleToPort[portNumber];
	*dialType = p->dialType;
	Q_strcpy (clear, p->clear);
	Q_strcpy (init, p->startup);
	Q_strcpy (hangup, p->shutdown);
}

void
TTY_SetModemConfig (int portNumber, char *dialType, char *clear, char *init,
					char *hangup)
{
	ComPort    *p;

	p = handleToPort[portNumber];
	p->dialType = dialType[0];
	Q_strcpy (p->clear, clear);
	Q_strcpy (p->startup, init);
	Q_strcpy (p->shutdown, hangup);

	p->modemInitialized = false;

	Cvar_Set ("_config_modem_dialtype", dialType);
	Cvar_Set ("_config_modem_clear", clear);
	Cvar_Set ("_config_modem_init", init);
	Cvar_Set ("_config_modem_hangup", hangup);
}


static void
ResetComPortConfig (ComPort * p)
{
	p->useModem = false;
	p->uartType = UART_AUTO;
	p->uart = ISA_uarts[p->portNumber];
	p->irq = ISA_IRQs[p->portNumber];
	p->modemStatusIgnore = MSR_CD | MSR_CTS | MSR_DSR;
	p->baudBits = 115200 / 57600;
	p->lineControl = LCR_DATA_BITS_8 | LCR_STOP_BITS_1 | LCR_PARITY_NONE;
	Q_strcpy (p->clear, "ATZ");
	Q_strcpy (p->startup, "");
	Q_strcpy (p->shutdown, "AT H");
	p->modemRang = false;
	p->modemConnected = false;
	p->statusUpdated = false;
	p->outputQueue.head = p->outputQueue.tail = 0;
	p->inputQueue.head = p->inputQueue.tail = 0;
}


static void
ComPort_Enable (ComPort * p)
{
	void        (*isr) (void);
	int         n;
	byte        b;

	if (p->enabled) {
		Con_Printf ("Already enabled\n");
		return;
	}
	// disable all UART interrupts
	outportb (p->uart + INTERRUPT_ENABLE_REGISTER, 0);

	// clear out any buffered uncoming data
	while ((inportb (p->uart + LINE_STATUS_REGISTER)) & LSR_DATA_READY)
		inportb (p->uart + RECEIVE_BUFFER_REGISTER);

	// get the current line and modem status
	p->modemStatus =
		(inportb (p->uart + MODEM_STATUS_REGISTER) & MODEM_STATUS_MASK) |
		p->modemStatusIgnore;
	p->lineStatus = inportb (p->uart + LINE_STATUS_REGISTER);

	// clear any UART interrupts
	do {
		n = inportb (p->uart + INTERRUPT_ID_REGISTER) & 7;
		if (n == IIR_RX_DATA_READY_INTERRUPT)
			inportb (p->uart + RECEIVE_BUFFER_REGISTER);
	} while (!(n & 1));

	if (p->uartType == UART_AUTO) {
		outportb (p->uart + FIFO_CONTROL_REGISTER, FCR_FIFO_ENABLE);
		b = inportb (p->uart + INTERRUPT_ID_REGISTER);
		if ((b & IIR_FIFO_ENABLED) == IIR_FIFO_ENABLED)
			p->uartType = UART_16550;
		else
			p->uartType = UART_8250;
	}
	// save the old interrupt handler
	_go32_dpmi_get_protected_mode_interrupt_vector (p->irq + 8,
													&p->protectedModeSaveInfo);

	if (p->uartType == UART_8250) {
		outportb (p->uart + FIFO_CONTROL_REGISTER, 0);
		if (p == handleToPort[0])
			isr = COM1_ISR_8250;
		else
			isr = COM2_ISR_8250;
	} else {
		outportb (p->uart + FIFO_CONTROL_REGISTER,
				  FCR_FIFO_ENABLE | FCR_RCVR_FIFO_RESET | FCR_XMIT_FIFO_RESET |
				  FCR_TRIGGER_08);
		if (p == handleToPort[0])
			isr = COM1_ISR_16550;
		else
			isr = COM2_ISR_16550;
	}

	p->protectedModeInfo.pm_offset = (int) isr;

	n = _go32_dpmi_allocate_iret_wrapper (&p->protectedModeInfo);
	if (n) {
		Con_Printf ("serial: protected mode callback allocation failed\n");
		return;
	}
	// disable interrupts at the processor
	disable ();

	// install our interrupt handlers now
	_go32_dpmi_set_protected_mode_interrupt_vector (p->irq + 8,
													&p->protectedModeInfo);

	// enable our interrupt at the PIC
	outportb (0x21, inportb (0x21) & ~(1 << p->irq));

	// enable interrupts at the processor
	enable ();

	// enable interrupts at the PIC
	outportb (0x20, 0xc2);

	// set baud rate & line control
	outportb (p->uart + LINE_CONTROL_REGISTER, LCR_DLAB | p->lineControl);
	outportb (p->uart, p->baudBits);
	outportb (p->uart + 1, 0);
	outportb (p->uart + LINE_CONTROL_REGISTER, p->lineControl);

	// set modem control register & enable uart interrupt generation
	outportb (p->uart + MODEM_CONTROL_REGISTER, MCR_OUT2 | MCR_RTS | MCR_DTR);

	// enable the individual interrupts at the uart
	outportb (p->uart + INTERRUPT_ENABLE_REGISTER,
			  IER_RX_DATA_READY | IER_TX_HOLDING_REGISTER_EMPTY |
			  IER_LINE_STATUS | IER_MODEM_STATUS);

	p->enabled = true;
}


static void
ComPort_Disable (ComPort * p)
{
	if (!p->enabled) {
		Con_Printf ("Already disabled\n");
		return;
	}
	// disable interrupts at the uart
	outportb (p->uart + INTERRUPT_ENABLE_REGISTER, 0);

	// disable our interrupt at the PIC
	outportb (0x21, inportb (0x21) | (1 << p->irq));

	// disable interrupts at the processor
	disable ();

	// restore the old interrupt handler
	_go32_dpmi_set_protected_mode_interrupt_vector (p->irq + 8,
													&p->protectedModeSaveInfo);
	_go32_dpmi_free_iret_wrapper (&p->protectedModeInfo);

	// enable interrupts at the processor
	enable ();

	p->enabled = false;
}


static int
CheckStatus (ComPort * p)
{
	int         ret = 0;

	if (p->statusUpdated) {
		p->statusUpdated = false;

		if (p->lineStatus & (LSR_OVERRUN_ERROR | LSR_PARITY_ERROR |
							 LSR_FRAMING_ERROR | LSR_BREAK_DETECT)) {
			if (p->lineStatus & LSR_OVERRUN_ERROR)
				Con_DPrintf ("Serial overrun error\n");
			if (p->lineStatus & LSR_PARITY_ERROR)
				Con_DPrintf ("Serial parity error\n");
			if (p->lineStatus & LSR_FRAMING_ERROR)
				Con_DPrintf ("Serial framing error\n");
			if (p->lineStatus & LSR_BREAK_DETECT)
				Con_DPrintf ("Serial break detect\n");
			ret = ERR_TTY_LINE_STATUS;
		}

		if ((p->modemStatus & MODEM_STATUS_MASK) != MODEM_STATUS_MASK) {
			if (!(p->modemStatus & MSR_CTS))
				Con_Printf ("Serial lost CTS\n");
			if (!(p->modemStatus & MSR_DSR))
				Con_Printf ("Serial lost DSR\n");
			if (!(p->modemStatus & MSR_CD))
				Con_Printf ("Serial lost Carrier\n");
			ret = ERR_TTY_MODEM_STATUS;
		}
	}

	return ret;
}


static void
Modem_Init (ComPort * p)
{
	double      start;
	char       *response;

	Con_Printf ("Initializing modem...\n");

	// write 0 to MCR, wait 1/2 sec, then write the real value back again
	// I got this from the guys at head-to-head who say it's necessary.
	outportb (p->uart + MODEM_CONTROL_REGISTER, 0);
	start = Sys_DoubleTime ();
	while ((Sys_DoubleTime () - start) < 0.5);
	outportb (p->uart + MODEM_CONTROL_REGISTER, MCR_OUT2 | MCR_RTS | MCR_DTR);
	start = Sys_DoubleTime ();
	while ((Sys_DoubleTime () - start) < 0.25);

	if (*p->clear) {
		Modem_Command (p, p->clear);
		start = Sys_DoubleTime ();
		while (1) {
			if ((Sys_DoubleTime () - start) > 3.0) {
				Con_Printf ("No response - clear failed\n");
				p->enabled = false;
				goto failed;
			}
			response = Modem_Response (p);
			if (!response)
				continue;
			if (Q_strncmp (response, "OK", 2) == 0)
				break;
			if (Q_strncmp (response, "ERROR", 5) == 0) {
				p->enabled = false;
				goto failed;
			}
		}
	}

	if (*p->startup) {
		Modem_Command (p, p->startup);
		start = Sys_DoubleTime ();
		while (1) {
			if ((Sys_DoubleTime () - start) > 3.0) {
				Con_Printf ("No response - init failed\n");
				p->enabled = false;
				goto failed;
			}
			response = Modem_Response (p);
			if (!response)
				continue;
			if (Q_strncmp (response, "OK", 2) == 0)
				break;
			if (Q_strncmp (response, "ERROR", 5) == 0) {
				p->enabled = false;
				goto failed;
			}
		}
	}

	p->modemInitialized = true;
	return;

  failed:
	if (m_return_onerror) {
		key_dest = key_menu;
		m_state = m_return_state;
		m_return_onerror = false;
		Q_strcpy (m_return_reason, "Initialization Failed");
	}
	return;
}


void
TTY_Enable (int handle)
{
	ComPort    *p;

	p = handleToPort[handle];
	if (p->enabled)
		return;

	ComPort_Enable (p);

	if (p->useModem && !p->modemInitialized)
		Modem_Init (p);
}


int
TTY_Open (int serialPortNumber)
{
	return serialPortNumber;
}


void
TTY_Close (int handle)
{
	ComPort    *p;
	double      startTime;

	p = handleToPort[handle];

	startTime = Sys_DoubleTime ();
	while ((Sys_DoubleTime () - startTime) < 1.0)
		if (EMPTY (p->outputQueue))
			break;

	if (p->useModem) {
		if (p->modemConnected)
			Modem_Hangup (p);
	}
}


int
TTY_ReadByte (int handle)
{
	int         ret;
	ComPort    *p;

	p = handleToPort[handle];

	if ((ret = CheckStatus (p)) != 0)
		return ret;

	if (EMPTY (p->inputQueue))
		return ERR_TTY_NODATA;

	DEQUEUE (p->inputQueue, ret);
	return (ret & 0xff);
}


int
TTY_WriteByte (int handle, byte data)
{
	ComPort    *p;

	p = handleToPort[handle];
	if (FULL (p->outputQueue))
		return -1;

	ENQUEUE (p->outputQueue, data);
	return 0;
}


void
TTY_Flush (int handle)
{
	byte        b;
	ComPort    *p;

	p = handleToPort[handle];

	if (inportb (p->uart + LINE_STATUS_REGISTER) & LSR_TRANSMITTER_EMPTY) {
		DEQUEUE (p->outputQueue, b);
		outportb (p->uart, b);
	}
}


int
TTY_Connect (int handle, char *host)
{
	double      start;
	ComPort    *p;
	char       *response = NULL;
	keydest_t   save_key_dest;
	byte        dialstring[64];
	byte        b;

	p = handleToPort[handle];

	if ((p->modemStatus & MODEM_STATUS_MASK) != MODEM_STATUS_MASK) {
		Con_Printf ("Serial: line not ready (");
		if ((p->modemStatus & MSR_CTS) == 0)
			Con_Printf (" CTS");
		if ((p->modemStatus & MSR_DSR) == 0)
			Con_Printf (" DSR");
		if ((p->modemStatus & MSR_CD) == 0)
			Con_Printf (" CD");
		Con_Printf (" )");
		return -1;
	}
	// discard any scraps in the input buffer
	while (!EMPTY (p->inputQueue))
		DEQUEUE (p->inputQueue, b);

	CheckStatus (p);

	if (p->useModem) {
		save_key_dest = key_dest;
		key_dest = key_console;
		key_count = -2;

		Con_Printf ("Dialing...\n");
		snprintf (dialstring, sizeof (dialstring), "AT D%c %s\r", p->dialType,
				  host);
		Modem_Command (p, dialstring);
		start = Sys_DoubleTime ();
		while (1) {
			if ((Sys_DoubleTime () - start) > 60.0) {
				Con_Printf ("Dialing failure!\n");
				break;
			}

			IN_SendKeyEvents ();
			if (key_count == 0) {
				if (key_lastpress != K_ESCAPE) {
					key_count = -2;
					continue;
				}
				Con_Printf ("Aborting...\n");
				while ((Sys_DoubleTime () - start) < 5.0);
				disable ();
				p->outputQueue.head = p->outputQueue.tail = 0;
				p->inputQueue.head = p->inputQueue.tail = 0;
				outportb (p->uart + MODEM_CONTROL_REGISTER,
						  inportb (p->uart +
								   MODEM_CONTROL_REGISTER) & ~MCR_DTR);
				enable ();
				start = Sys_DoubleTime ();
				while ((Sys_DoubleTime () - start) < 0.75);
				outportb (p->uart + MODEM_CONTROL_REGISTER,
						  inportb (p->uart + MODEM_CONTROL_REGISTER) | MCR_DTR);
				response = "Aborted";
				break;
			}

			response = Modem_Response (p);
			if (!response)
				continue;
			if (Q_strncmp (response, "CONNECT", 7) == 0) {
				disable ();
				p->modemRang = true;
				p->modemConnected = true;
				p->outputQueue.head = p->outputQueue.tail = 0;
				p->inputQueue.head = p->inputQueue.tail = 0;
				enable ();
				key_dest = save_key_dest;
				key_count = 0;
				m_return_onerror = false;
				return 0;
			}
			if (Q_strncmp (response, "NO CARRIER", 10) == 0)
				break;
			if (Q_strncmp (response, "NO DIALTONE", 11) == 0)
				break;
			if (Q_strncmp (response, "NO DIAL TONE", 12) == 0)
				break;
			if (Q_strncmp (response, "NO ANSWER", 9) == 0)
				break;
			if (Q_strncmp (response, "BUSY", 4) == 0)
				break;
			if (Q_strncmp (response, "ERROR", 5) == 0)
				break;
		}
		key_dest = save_key_dest;
		key_count = 0;
		if (m_return_onerror) {
			key_dest = key_menu;
			m_state = m_return_state;
			m_return_onerror = false;
			Q_strncpy (m_return_reason, response, 31);
		}
		return -1;
	}
	m_return_onerror = false;
	return 0;
}


void
TTY_Disconnect (int handle)
{
	ComPort    *p;

	p = handleToPort[handle];

	if (p->useModem && p->modemConnected)
		Modem_Hangup (p);
}


qboolean
TTY_CheckForConnection (int handle)
{
	ComPort    *p;

	p = handleToPort[handle];

	CheckStatus (p);

	if (p->useModem) {
		if (!p->modemRang) {
			if (!Modem_Response (p))
				return false;

			if (Q_strncmp (p->buffer, "RING", 4) == 0) {
				Modem_Command (p, "ATA");
				p->modemRang = true;
				p->timestamp = net_time;
			}
			return false;
		}
		if (!p->modemConnected) {
			if ((net_time - p->timestamp) > 35.0) {
				Con_Printf ("Unable to establish modem connection\n");
				p->modemRang = false;
				return false;
			}

			if (!Modem_Response (p))
				return false;

			if (Q_strncmp (p->buffer, "CONNECT", 7) != 0)
				return false;

			disable ();
			p->modemConnected = true;
			p->outputQueue.head = p->outputQueue.tail = 0;
			p->inputQueue.head = p->inputQueue.tail = 0;
			enable ();
			Con_Printf ("Modem Connect\n");
			return true;
		}
		return true;
	}
	// direct connect case
	if (EMPTY (p->inputQueue))
		return false;
	return true;
}


qboolean
TTY_IsEnabled (int serialPortNumber)
{
	return handleToPort[serialPortNumber]->enabled;
}


qboolean
TTY_IsModem (int serialPortNumber)
{
	return handleToPort[serialPortNumber]->useModem;
}


qboolean
TTY_OutputQueueIsEmpty (int handle)
{
	return EMPTY (handleToPort[handle]->outputQueue);
}


void
Com_f (void)
{
	ComPort    *p;
	int         portNumber;
	int         i;
	int         n;

	// first, determine which port they're messing with
	portNumber = Q_atoi (Cmd_Argv (0) + 3) - 1;
	if (portNumber > 1)
		return;
	p = handleToPort[portNumber];

	if (Cmd_Argc () == 1) {
		Con_Printf ("Settings for COM%i\n", portNumber + 1);
		Con_Printf ("enabled:   %s\n", p->enabled ? "true" : "false");
		Con_Printf ("uart:      ");
		if (p->uartType == UART_AUTO)
			Con_Printf ("auto\n");
		else if (p->uartType == UART_8250)
			Con_Printf ("8250\n");
		else
			Con_Printf ("16550\n");
		Con_Printf ("port:      %x\n", p->uart);
		Con_Printf ("irq:       %i\n", p->irq);
		Con_Printf ("baud:      %i\n", 115200 / p->baudBits);
		Con_Printf ("CTS:       %s\n",
					(p->modemStatusIgnore & MSR_CTS) ? "ignored" : "honored");
		Con_Printf ("DSR:       %s\n",
					(p->modemStatusIgnore & MSR_DSR) ? "ignored" : "honored");
		Con_Printf ("CD:        %s\n",
					(p->modemStatusIgnore & MSR_CD) ? "ignored" : "honored");
		if (p->useModem) {
			Con_Printf ("type:      Modem\n");
			Con_Printf ("clear:     %s\n", p->clear);
			Con_Printf ("startup:   %s\n", p->startup);
			Con_Printf ("shutdown:  %s\n", p->shutdown);
		} else
			Con_Printf ("type:      Direct connect\n");

		return;
	}


	if (Cmd_CheckParm ("disable")) {
		if (p->enabled)
			ComPort_Disable (p);
		p->modemInitialized = false;
		return;
	}

	if (Cmd_CheckParm ("reset")) {
		ComPort_Disable (p);
		ResetComPortConfig (p);
		return;
	}

	if ((i = Cmd_CheckParm ("port")) != 0) {
		if (p->enabled) {
			Con_Printf ("COM port must be disabled to change port\n");
			return;
		}
		p->uart = Q_atoi (Cmd_Argv (i + 1));
	}

	if ((i = Cmd_CheckParm ("irq")) != 0) {
		if (p->enabled) {
			Con_Printf ("COM port must be disabled to change irq\n");
			return;
		}
		p->irq = Q_atoi (Cmd_Argv (i + 1));
	}

	if ((i = Cmd_CheckParm ("baud")) != 0) {
		if (p->enabled) {
			Con_Printf ("COM port must be disabled to change baud\n");
			return;
		}
		n = Q_atoi (Cmd_Argv (i + 1));
		if (n == 0)
			Con_Printf ("Invalid baud rate specified\n");
		else
			p->baudBits = 115200 / n;
	}

	if (Cmd_CheckParm ("8250")) {
		if (p->enabled) {
			Con_Printf ("COM port must be disabled to change uart\n");
			return;
		}
		p->uartType = UART_8250;
	}
	if (Cmd_CheckParm ("16550")) {
		if (p->enabled) {
			Con_Printf ("COM port must be disabled to change uart\n");
			return;
		}
		p->uartType = UART_16550;
	}
	if (Cmd_CheckParm ("auto")) {
		if (p->enabled) {
			Con_Printf ("COM port must be disabled to change uart\n");
			return;
		}
		p->uartType = UART_AUTO;
	}

	if (Cmd_CheckParm ("pulse"))
		p->dialType = 'P';
	if (Cmd_CheckParm ("tone"))
		p->dialType = 'T';

	if (Cmd_CheckParm ("direct"))
		p->useModem = false;
	if (Cmd_CheckParm ("modem"))
		p->useModem = true;

	if ((i = Cmd_CheckParm ("clear")) != 0) {
		Q_strncpy (p->clear, Cmd_Argv (i + 1), 16);
	}

	if ((i = Cmd_CheckParm ("startup")) != 0) {
		Q_strncpy (p->startup, Cmd_Argv (i + 1), 32);
		p->modemInitialized = false;
	}

	if ((i = Cmd_CheckParm ("shutdown")) != 0) {
		Q_strncpy (p->shutdown, Cmd_Argv (i + 1), 16);
	}

	if (Cmd_CheckParm ("-cts")) {
		p->modemStatusIgnore |= MSR_CTS;
		p->modemStatus |= MSR_CTS;
	}

	if (Cmd_CheckParm ("+cts")) {
		p->modemStatusIgnore &= (~MSR_CTS);
		p->modemStatus =
			(inportb (p->uart + MODEM_STATUS_REGISTER) & MODEM_STATUS_MASK) |
			p->modemStatusIgnore;
	}

	if (Cmd_CheckParm ("-dsr")) {
		p->modemStatusIgnore |= MSR_DSR;
		p->modemStatus |= MSR_DSR;
	}

	if (Cmd_CheckParm ("+dsr")) {
		p->modemStatusIgnore &= (~MSR_DSR);
		p->modemStatus =
			(inportb (p->uart + MODEM_STATUS_REGISTER) & MODEM_STATUS_MASK) |
			p->modemStatusIgnore;
	}

	if (Cmd_CheckParm ("-cd")) {
		p->modemStatusIgnore |= MSR_CD;
		p->modemStatus |= MSR_CD;
	}

	if (Cmd_CheckParm ("+cd")) {
		p->modemStatusIgnore &= (~MSR_CD);
		p->modemStatus =
			(inportb (p->uart + MODEM_STATUS_REGISTER) & MODEM_STATUS_MASK) |
			p->modemStatusIgnore;
	}

	if (Cmd_CheckParm ("enable")) {
		if (!p->enabled)
			ComPort_Enable (p);
		if (p->useModem && !p->modemInitialized)
			Modem_Init (p);
	}
}


int
TTY_Init (void)
{
	int         n;
	ComPort    *p;

	for (n = 0; n < NUM_COM_PORTS; n++) {
		p = (ComPort *) Hunk_AllocName (sizeof (ComPort), "comport");
		if (p == NULL)
			Sys_Error ("Hunk alloc failed for com port\n");
		p->next = portList;
		portList = p;
		handleToPort[n] = p;
		p->portNumber = n;
		p->dialType = 'T';
		snprintf (p->name, sizeof (p->name), "com%u", n + 1);
		Cmd_AddCommand (p->name, Com_f, "No Description");
		ResetComPortConfig (p);
	}

	GetComPortConfig = TTY_GetComPortConfig;
	SetComPortConfig = TTY_SetComPortConfig;
	GetModemConfig = TTY_GetModemConfig;
	SetModemConfig = TTY_SetModemConfig;

	return 0;
}


void
TTY_Shutdown (void)
{
	int         n;
	ComPort    *p;

	for (n = 0; n < NUM_COM_PORTS; n++) {
		p = handleToPort[n];
		if (p->enabled) {
			while (p->modemConnected)
				NET_Poll ();
			ComPort_Disable (p);
		}
	}
}


static int
Modem_Command (ComPort * p, char *commandString)
{
	byte        b;

	if (CheckStatus (p))
		return -1;

	disable ();
	p->outputQueue.head = p->outputQueue.tail = 0;
	p->inputQueue.head = p->inputQueue.tail = 0;
	enable ();
	p->bufferUsed = 0;

	while (*commandString)
		ENQUEUE (p->outputQueue, *commandString++);
	ENQUEUE (p->outputQueue, '\r');

	// get the transmit rolling
	DEQUEUE (p->outputQueue, b);
	outportb (p->uart, b);

	return 0;
}


static char *
Modem_Response (ComPort * p)
{
	byte        b;

	if (CheckStatus (p))
		return NULL;

	while (!EMPTY (p->inputQueue)) {
		DEQUEUE (p->inputQueue, b);

		if (p->bufferUsed == (sizeof (p->buffer) - 1))
			b = '\r';

		if (b == '\r' && p->bufferUsed) {
			p->buffer[p->bufferUsed] = 0;
			Con_Printf ("%s\n", p->buffer);
			SCR_UpdateScreen ();
			p->bufferUsed = 0;
			return p->buffer;
		}

		if (b < ' ' || b > 'z')
			continue;
		p->buffer[p->bufferUsed] = b;
		p->bufferUsed++;
	}

	return NULL;
}


static void Modem_Hangup2 (ComPort * p);
static void Modem_Hangup3 (ComPort * p);
static void Modem_Hangup4 (ComPort * p);

static void
Modem_Hangup (ComPort * p)
{
	Con_Printf ("Hanging up modem...\n");
	disable ();
	p->modemRang = false;
	p->outputQueue.head = p->outputQueue.tail = 0;
	p->inputQueue.head = p->inputQueue.tail = 0;
	outportb (p->uart + MODEM_CONTROL_REGISTER,
			  inportb (p->uart + MODEM_CONTROL_REGISTER) & ~MCR_DTR);
	enable ();
	p->poll.procedure = Modem_Hangup2;
	p->poll.arg = p;
	SchedulePollProcedure (&p->poll, 1.5);
}

static void
Modem_Hangup2 (ComPort * p)
{
	outportb (p->uart + MODEM_CONTROL_REGISTER,
			  inportb (p->uart + MODEM_CONTROL_REGISTER) | MCR_DTR);
	Modem_Command (p, "+++");
	p->poll.procedure = Modem_Hangup3;
	SchedulePollProcedure (&p->poll, 1.5);
}

static void
Modem_Hangup3 (ComPort * p)
{
	Modem_Command (p, p->shutdown);
	p->poll.procedure = Modem_Hangup4;
	SchedulePollProcedure (&p->poll, 1.5);
}

static void
Modem_Hangup4 (ComPort * p)
{
	Modem_Response (p);
	Con_Printf ("Hangup complete\n");
	p->modemConnected = false;
}