Category : C++ Source Code
Archive   : CPPTASK.ZIP
Filename : TSKSIO.CPP

/*
CPPTask - A Multitasking Kernel For C++

Version 1.0 08-12-91

Ported by Rich Smith from:

Public Domain Software written by
Thomas Wagner
Patschkauer Weg 31
D-1000 Berlin 33
West Germany

TSKSIO.CPP - Serial I/O interface routines.

Subroutines:
sioint3
sioint4
commport::chng_rts
commport::transmit_ready
commport::modem_status_int
commport::receive_ready
commport::sioint
commport::commport
commport::~commport
commport::change_rts
commport::change_dtr
commport::change_baud
commport::change_parity
commport::change_wordlength
commport::change_stopbits
commport::watch_modem
commport::protocol
commport::send
commport::receive
commport::rcv_overrun
commport::check
commport::modem_status
commport::complete
commport::wait_complete
commport::flush_receive

The tables used are:

port_list The pointer to the list of defined ports. Newly
defined ports are added to the end of the list.
Ports can never be deleted. Each port descriptor
contains the hardware info for the port, plus a
pointer to the associated sio-control-block if the
port was initialized.

port_last The pointer to the last element in port_list.

irq_array Is an array of pointers to sio-control-blocks. For
each possible IRQ-line the entry in this table points
to the first block active for this line. If the IRQ
is shared, sio-blocks are chained into this list via
their "next" pointer.

irq_procs Contains the pointer to the interrupt handler function
for the corresponding IRQ-line.

port_descr Contains the statically defined port descriptor blocks.

NOTE: You can not dynamically define ports for IRQ-lines that
have no interrupt handler function defined. To be completely
flexible, you would have to define sioint-handlers for all
possible IRQs and enter the addresses into the irq_procs array.

CAUTION: Please restrict the installation and removal of comm-
ports to *one* task. The manipulation of the lists is
not protected, so simultaneous install/remove calls
may cause trouble. Since ports are normally installed and
removed in the main task, the protection of critical regions
seemed unnecessary.

CAUTION: Shared interrupt logic and IRQ-lines above 4 were not
tested due to the lack of suitable hardware. Changes may
be necessary in the handling of the modem control register
OUT2 line that normally controls interrupt enable, depending
on the multiport-hardware installed in the target system.

*/

#include "task.hpp"
#include "sio.hpp"

#define MAX_IRQ 16 /* Maximum number of interrupt lines,
16 for AT, 8 for XT. Can be left at 16 */

#define CHAIN_IRQBIT 0x04 /* Chained int controller IRQ bit */

#define RESTORE_DEFAULT 1 /* Restore parameter for remove_all */

#define RTS 0x02
#define DTR 0x01
#define OUT2 0x08

#define ERR_MASK 0x1e

#define inta00 0x20 /* 8259 interrupt controller control-port */
#define inta01 0x21 /* 8259 interrupt controller mask-port */

#define inta10 0xa0 /* secondary 8259 control-port for IRQ 8-15 */
#define inta11 0xa1 /* secondary 8259 mask-port for IRQ 8-15 */

#define rdserv 0x0b /* read service register control value */
#define eoi 0x20 /* end of interrupt signal for 8259 */

#define intdata 0x0b /* Enable Interrupts except Line status */

#define rxreadybit 0x01
#define txemptybit 0x40
#define txreadybit 0x20
#define framingbit 0x08
#define breakbit 0x10


/* Note: In version 1.1, port offsets start at 0, not 8 */

#define linecontrol 0x03
#define linestatus 0x05
#define intid 0x02
#define intenable 0x01
#define modemcontrol 0x04
#define modemstatus 0x06
#define receivedata 0x00
#define transmitdata 0x00

#define baudreg_dll 0x00 /* baud rate least significant byte */
#define baudreg_dlm 0x01 /* baud rate most significant byte */

/*
Default values for initialising the ports.
Change to your liking (but remember that OUT2 must be set in the
modem control register to allow interrupts to come through with
normal controllers).
*/

#define dflt_modcon 0x0b /* Modem Control: Activate DTR, RTS, OUT2 */
#define dflt_baud 96 /* Baud Rate Divisor: 1200 Baud */
#define dflt_lcon 0x03 /* Line Control: No Parity, 1 Stop, 8 Data */

/*
Defined baud rates. You may expand this table with non-standard
rates if desired.
*/

local long baud_table [] = {
50L, 2304L,
75L, 1536L,
110L, 1047L,
134L, 857L,
150L, 768L,
300L, 384L,
600L, 192L,
1200L, 96L,
1800L, 64L,
2000L, 58L,
2400L, 48L,
3600L, 32L,
4800L, 24L,
7200L, 16L,
9600L, 12L,
19200L, 6L,
38400L, 3L,
0L, 0L };

local byte force_transmit_ready; /* flag to indicate
transmitter needs service */

/*-------------------------------------------------------------------------*/

/*
To add static support for other COM-Ports, define
- Port base
- IRQ-Line
- Interrupt vector
here, and add the necessary data to the port_descr array.
If the port does *not* share an IRQ with the predefined ports,
define the corresponding interrupt function by duplicating siointx,
and place the entry for this function into the irq_procs array.

*/

#define STATIC_PORTS 2 /* Number of statically defined ports */

/* Note: In version 1.1, port offsets start at 0, not 8 */

#define com1_base 0x3f8 /* COM1 port base */
#define com2_base 0x2f8 /* COM2 port base */

#define com1_irq 4 /* IRQ-Line for COM1 */
#define com2_irq 3 /* IRQ-Line for COM2 */

#define com1_vect 0x0c /* Interrupt vector for COM1 */
#define com2_vect 0x0b /* Interrupt vector for COM2 */

/*-------------------------------------------------------------------------*/


typedef void (interrupt far * intprocptr)(void);

void interrupt far sioint3 (void);
void interrupt far sioint4 (void);

/*
Table of Interrupt handler functions for each IRQ line.
*/

local intprocptr irq_procs [MAX_IRQ] = { NULL, /* IRQ 0 */
NULL, /* IRQ 1 */
NULL, /* IRQ 2 */
(intprocptr)sioint3, /* IRQ 3 */
(intprocptr)sioint4, /* IRQ 4 */
NULL, /* IRQ 5 */
NULL, /* IRQ 6 */
NULL, /* IRQ 7 */
NULL, /* IRQ 8 */
NULL, /* IRQ 9 */
NULL, /* IRQ 10 */
NULL, /* IRQ 11 */
NULL, /* IRQ 12 */
NULL, /* IRQ 13 */
NULL, /* IRQ 14 */
NULL }; /* IRQ 15 */


/* When adding entries to port_descr, be sure to chain the
elements in ascending order via the first field, and to
increase the internal port number in the second field. */

local port_data port_descr [STATIC_PORTS] = {
{ &port_descr[1], 0, NULL, com1_base, com1_irq, com1_vect },
{ NULL, 1, NULL, com2_base, com2_irq, com2_vect }
};

local commptr irq_array [MAX_IRQ] = { NULL };

local portptr port_list = &port_descr [0];
local portptr port_last = &port_descr [1];

local int ports = STATIC_PORTS;

extern funcptr v24_remove_func;

/*-------------------------------------------------------------------------*/


void commport::chng_rts (int on)
{
rtsoff = (byte)(!on);
cmodcontrol = (cmodcontrol & ~RTS) | ((on) ? RTS : 0);
tsk_outp (port_base + modemcontrol, cmodcontrol);
}


void commport::transmit_ready (void)
{
int i;

force_transmit_ready = 0;

if ((i = r_xoff) < 0)
{
tsk_outp (port_base + transmitdata, (i == -1) ? XOFF : XON);
r_xoff = (i == -1) ? 1 : 0;
xmit_pending = 1;
return;
}

xmit_pending = 0;

if (!(wait_xmit = (byte)(xmit_pipe.check_pipe () != -1)))
return;

if ((modem_flags & modstat) ^ modem_flags)
return;

if (flags & XONXOFF && t_xoff)
return;

wait_xmit = 0;

if ((i = xmit_pipe.c_read_pipe ()) < 0)
return;

tsk_outp (port_base + transmitdata, (byte)i);
xmit_pending = 1;
}


void commport::modem_status_int (void)
{
modstat = tsk_inp (port_base + modemstatus);

if (wait_xmit)
transmit_ready ();
}


void commport::receive_ready (void)
{
word status;
word ch;

while ((status = tsk_inp (port_base + linestatus)) & rxreadybit)
{
/* Correct for possible loss of transmit interrupt from IIR register */
if (status & txreadybit)
force_transmit_ready = 1;

tsk_nop ();
ch = tsk_inp (port_base + receivedata);

if (flags & XONXOFF)
{
if (ch == XON)
{
t_xoff = 0;
if (wait_xmit)
transmit_ready ();
continue;
}
else if (ch == XOFF)
{
t_xoff = 1;
continue;
}
if (!r_xoff &&
rcv_pipe.wpipe_free () < xoff_threshold)
{
r_xoff = -1;
if (!xmit_pending)
transmit_ready ();
}
}

if (flags & RTSCTS && !rtsoff)
if (rcv_pipe.wpipe_free () < xoff_threshold)
chng_rts (0);

status = (status & ERR_MASK) << 8;
if (rcv_pipe.c_write_wpipe (ch | status) < 0)
overrun = 1;
}
}


/*-------------------------------------------------------------------------*/


void commport::sioint (void)
{
int id;

force_transmit_ready = 0;

while (!((id = tsk_inp (port_base + intid)) & 1))
switch (id & 0x07)
{
case 0x00: modem_status_int ();
break;

case 0x02: transmit_ready ();
break;

case 0x04: receive_ready ();
break;

/* case 0x06: line_status_int (); (currently not used)
break;
*/
}
if (force_transmit_ready)
transmit_ready ();
}


void interrupt far sioint3 (void)
{
commptr curr;

tsk_sti ();
for (curr = irq_array [3]; curr != NULL; curr = curr->next)
curr->sioint ();

tsk_cli ();
/* NOTE: for IRQ's 8-15, add the following here:
tsk_outp (inta10, eoi);
*/
tsk_outp (inta00, eoi);
}


void interrupt far sioint4 (void)
{
commptr curr;

tsk_sti ();
for (curr = irq_array [4]; curr != NULL; curr = curr->next)
curr->sioint ();

tsk_cli ();
/* NOTE: for IRQ's 8-15, add the following here:
tsk_outp (inta10, eoi);
*/
tsk_outp (inta00, eoi);
}

/*-------------------------------------------------------------------------*/

commport::commport (int portnum, int init,
farptr rcvbuf, word rcvsize,
farptr xmitbuf, word xmitsize)
:xmit_pipe(xmitbuf, xmitsize), rcv_pipe(rcvbuf, rcvsize)
{
portptr portp;
int pbase;
intprocptr far *intptr;
int i, inta;

if (port < 0 || !rcvsize || !xmitsize)
return;

portp = port_list;

if (portnum & 0x80) /* Relative port number */
{
portnum &= 0x7f;
if (portnum > 4)
return;
pbase = *((wordptr)(MK_FP (0x40, portnum * 2)));
if (!pbase)
return;

for (portnum = 0; portnum < ports; portnum++, portp = portp->next)
if (portp->base == pbase)
break;

if (portnum >= ports)
return;
}
else
{
if (portnum > ports)
return;
for (i = 0; i < portnum; i++)
portp = portp->next;
}

if (portp->sio != NULL) /* Port already in use ? */
return;

portp->sio = this;

pbase = port_base = portp->base;
port = portp;

/* Check if port accessible by modifying the modem control register */

i = cmodcontrol = save_mcon = tsk_inp (pbase + modemcontrol);
if (i & 0xe0)
{
port->sio = NULL;
return;
}
tsk_nop ();
tsk_outp (pbase + modemcontrol, 0xe0 | i);
tsk_nop ();
if (tsk_inp (pbase + modemcontrol) != (byte) i)
{
port->sio = NULL;
return;
}

/* Port seems OK */

civect = portp->vector;
irqbit = (byte)(1 << (portp->irq & 0x07));

wait_xmit = xmit_pending = 0;
overrun = 0;
flags = 0;
modem_flags = 0;
r_xoff = t_xoff = 0;
rtsoff = 0;
restore = 1;

clcontrol = save_lcon = tsk_inp (pbase + linecontrol);
tsk_nop ();
save_inten = tsk_inp (pbase + intenable);
tsk_nop ();

if (init)
{
clcontrol = dflt_lcon;
cmodcontrol = dflt_modcon;
}

tsk_outp (pbase + linecontrol, clcontrol | 0x80);
tsk_nop ();
save_bd1 = tsk_inp (pbase + baudreg_dll);
tsk_nop ();
save_bd2 = tsk_inp (pbase + baudreg_dlm);
tsk_nop ();
tsk_outp (pbase + linecontrol, clcontrol);
tsk_nop ();

tsk_outp (pbase + intenable, 0);

if (irq_array [portp->irq] == NULL)
{
intptr = (intprocptr far *)MK_FP (0, civect * 4);
tsk_cli ();
savvect = *intptr;
*intptr = irq_procs [portp->irq];
tsk_sti ();
}

if (init)
{
tsk_outp (pbase + linecontrol, dflt_lcon | 0x80);
tsk_nop ();
tsk_outp (pbase + baudreg_dll, dflt_baud);
tsk_nop ();
tsk_outp (pbase + baudreg_dlm, dflt_baud >> 8);
tsk_nop ();
tsk_outp (pbase + linecontrol, dflt_lcon);
tsk_nop ();
tsk_outp (pbase + modemcontrol, dflt_modcon);
tsk_nop ();
}
else
{
i = tsk_inp (pbase + modemcontrol) | OUT2;
tsk_nop ();
tsk_outp (pbase + modemcontrol, i);
tsk_nop ();
}

while (tsk_inp (pbase + linestatus) & rxreadybit)
{
tsk_nop ();
tsk_inp (pbase + receivedata);
tsk_nop ();
}
tsk_nop ();

tsk_inp (pbase + linestatus);
tsk_nop ();
modstat = tsk_inp (pbase + modemstatus);
tsk_nop ();
tsk_inp (pbase + intid);
tsk_nop ();

inta = (portp->irq > 7) ? inta11 : inta01;

if (irq_array [portp->irq] == NULL)
{
if (portp->irq > 7)
{
i = tsk_inp (inta01) & ~CHAIN_IRQBIT;
tsk_nop ();
tsk_outp (inta01, i);
}

save_irq = (byte)((i = tsk_inp (inta)) & irqbit);
tsk_nop ();
tsk_outp (inta, i & ~irqbit);
}
else
save_irq = (irq_array [portp->irq])->save_irq;

tsk_cli ();
next = irq_array [portp->irq];
irq_array [portp->irq] = this;
tsk_sti ();

/* Enable interrupts with correction for possible loss of the
first tranmit interrupt on INS8250 and INS8250-B chips */
for (;;)
{
if (tsk_inp (pbase + linestatus) & txreadybit)
{
break;
}
tsk_nop ();
}

tsk_nop ();
tsk_cli ();
tsk_outp (pbase + intenable, intdata);
tsk_nop ();
tsk_outp (pbase + intenable, intdata);
tsk_sti ();

}


commport::~commport ()
{
intprocptr far *intptr;
int pbase, i, inta;
portptr portp;
commptr curr, last;

pbase = port_base;
portp = port;

last = NULL;
curr = irq_array [portp->irq];
while (curr != this && curr != NULL)
{
last = curr;
curr = curr->next;
}
if (curr == NULL)
return;

tsk_outp (pbase + intenable, 0);
tsk_cli ();
if (last == NULL)
irq_array [portp->irq] = next;
else
last->next = next;
tsk_sti ();

inta = (portp->irq > 7) ? inta11 : inta01;

// ???? this was an input param, now a member that is set in constructor
if (restore)
{
tsk_outp (pbase + modemcontrol, save_mcon);
tsk_nop ();
tsk_outp (pbase + linecontrol, save_lcon | 0x80);
tsk_nop ();
tsk_outp (pbase + baudreg_dll, save_bd1);
tsk_nop ();
tsk_outp (pbase + baudreg_dlm, save_bd2);
tsk_nop ();
tsk_outp (pbase + linecontrol, save_lcon);
tsk_nop ();
if (irq_array [portp->irq] == NULL)
{
tsk_cli ();
tsk_outp (pbase + intenable, save_inten);
i = tsk_inp (inta) & ~irqbit;
tsk_nop ();
tsk_outp (inta, i | save_irq);
}
}
else if (irq_array [portp->irq] == NULL)
{
tsk_cli ();
i = tsk_inp (inta) | irqbit;
tsk_nop ();
tsk_outp (inta, i);
}

if (irq_array [portp->irq] == NULL)
{
tsk_cli ();
intptr = (intprocptr far *)MK_FP (0, civect * 4);
*intptr = (intprocptr)savvect;
}
tsk_sti ();

portp->sio = NULL;
}


/*-------------------------------------------------------------------------*/

/*
void change_rts (int on)
*/

void far commport::change_rts (int on)
{
cmodcontrol = (cmodcontrol & ~RTS) | ((on) ? RTS : 0);
tsk_outp (port_base + modemcontrol, cmodcontrol);
}

/*
void change_dtr (int on)
*/

void far commport::change_dtr (int on)
{
cmodcontrol = (cmodcontrol & ~DTR) | ((on) ? DTR : 0);
tsk_outp (port_base + modemcontrol, cmodcontrol);
}


/*
void far change_baud (int rate)
*/

void far commport::change_baud (long rate)
{
int i;

for (i = 0; baud_table [i]; i += 2)
if (baud_table [i] == rate)
break;
if (!(i = (int)baud_table [i + 1]))
return;

tsk_outp (port_base + linecontrol, clcontrol | (byte)0x80);
tsk_nop ();
tsk_outp (port_base + baudreg_dll, (byte)i);
tsk_nop ();
tsk_outp (port_base + baudreg_dlm, (byte)(i >> 8));
tsk_nop ();
tsk_outp (port_base + linecontrol, clcontrol);
}


void far commport::change_parity (int par)
{
clcontrol = (clcontrol & 0xc7) | par;
tsk_outp (port_base + linecontrol, clcontrol);
}


void far commport::change_wordlength (int len)
{
int i;

switch (len)
{
case 5: i = 0x00; break;
case 6: i = 0x01; break;
case 7: i = 0x02; break;
case 8: i = 0x03; break;
default: return;
}
clcontrol = (clcontrol & 0xfc) | i;
tsk_outp (port_base + linecontrol, clcontrol);
}


void far commport::change_stopbits (int n)
{
int i;

switch (n)
{
case 1: i = 0x00; break;
case 2: i = 0x04; break;
default: return;
}
clcontrol = (clcontrol & 0xfb) | i;
tsk_outp (port_base + linecontrol, clcontrol);
}


void far commport::watch_modem (byte flags)
{
modem_flags = flags & (CTS | DSR | RI | CD);
}


void far commport::protocol (int prot, word offthresh, word onthresh)
{
byte old;

old = flags;
flags = (byte)prot;
if (prot)
{
if (!offthresh)
offthresh = 10;
xoff_threshold = offthresh;
if (onthresh <= offthresh)
onthresh = offthresh + 10;
xon_threshold = onthresh;
}

if ((old & RTSCTS) != ((byte)prot & RTSCTS))
{
chng_rts (1);
modem_flags = (modem_flags & ~CTS) |
((prot & RTSCTS) ? CTS : 0);
}

if (!(prot & XONXOFF))
{
if (r_xoff)
r_xoff = -2;
t_xoff = 0;
}

if (!xmit_pending)
transmit_ready ();
}


/*-------------------------------------------------------------------------*/


int far commport::send (byte ch, dword timeout)
{
int res;

if ((res = xmit_pipe.write_pipe (ch, timeout)) < 0)
return res;
tsk_cli ();
if (!xmit_pending)
transmit_ready ();
tsk_sti ();
return 0;
}


int far commport::receive (dword timeout)
{
int res;

if ((res = (int)rcv_pipe.read_wpipe (timeout)) < 0)
return res;

if (!flags)
return res;

if (rcv_pipe.wpipe_free () > xon_threshold)
{
tsk_cli ();
if (r_xoff)
{
r_xoff = -2;
if (!xmit_pending)
transmit_ready ();
}
tsk_sti ();

if (rtsoff)
chng_rts (1);
}
return res;
}


int far commport::rcv_overrun (void)
{
int res;

res = overrun;
overrun = 0;
return res;
}


int far commport::check (void)
{
return rcv_pipe.check_wpipe ();
}


int far commport::modem_status (void)
{
return modstat;
}


int far commport::complete (void)
{
return (xmit_pipe.check_pipe () == -1);
}


int far commport::wait_complete (dword timeout)
{
return xmit_pipe.wait_pipe_empty (timeout);
}


void far commport::flush_receive (void)
{
rcv_pipe.flush_wpipe ();
}