/*++
Copyright (c) 1990 Microsoft Corporation
Module Name:
ixkdcom.c
Abstract:
This module contains a very simply package to do com I/O on machines
with standard AT com-ports. It is C code derived from the debugger's
com code. Likely does not work on a PS/2. (Only rewrote the thing
into C so we wouldn't have to deal with random debugger macros.)
Procedures to init a com object, set and query baud rate, output
character, input character.
Author:
Bryan M. Willman (bryanwi) 24-Sep-1990
Revision History:
John Vert (jvert) 12-Jun-1991
Added ability to check for com-port's existence and hook onto the
highest com-port available.
John Vert (jvert) 19-Jul-1991
Moved into HAL
--*/
#include "halp.h"
#include "ixkdcom.h"
#define TIMEOUT_COUNT 1024 * 200
UCHAR CpReadLsr (PCPPORT, UCHAR);
extern BOOLEAN HalpOwnsDisplay;
static UCHAR LastLsr, LastMsr;
VOID
CpInitialize (
PCPPORT Port,
PUCHAR Address,
ULONG Rate
)
/*++
Routine Description:
Fill in the com port port object, set the initial baud rate,
turn on the hardware.
Arguments:
Port - address of port object
Address - port address of the com port
(CP_COM1_PORT, CP_COM2_PORT)
Rate - baud rate (CP_BD_150 ... CP_BD_19200)
--*/
{
PUCHAR hwport;
UCHAR mcr, ier;
Port->Address = Address;
Port->Baud = 0;
CpSetBaud(Port, Rate);
//
// Assert DTR, RTS.
//
hwport = Port->Address;
hwport += COM_MCR;
mcr = MC_DTRRTS;
WRITE_PORT_UCHAR(hwport, mcr);
hwport = Port->Address;
hwport += COM_IEN;
ier = 0;
WRITE_PORT_UCHAR(hwport, ier);
}
VOID
CpSetBaud (
PCPPORT Port,
ULONG Rate
)
/*++
Routine Description:
Set the baud rate for the port and record it in the port object.
Arguments:
Port - address of port object
Rate - baud rate (CP_BD_150 ... CP_BD_56000)
--*/
{
ULONG divisorlatch;
PUCHAR hwport;
UCHAR lcr;
//
// compute the divsor
//
divisorlatch = CLOCK_RATE / Rate;
//
// set the divisor latch access bit (DLAB) in the line control reg
//
hwport = Port->Address;
hwport += COM_LCR; // hwport = LCR register
lcr = READ_PORT_UCHAR(hwport);
lcr |= LC_DLAB;
WRITE_PORT_UCHAR(hwport, lcr);
//
// set the divisor latch value.
//
hwport = Port->Address;
hwport += COM_DLM; // divisor latch msb
WRITE_PORT_UCHAR(hwport, (UCHAR)((divisorlatch >> 8) & 0xff));
hwport--; // divisor latch lsb
WRITE_PORT_UCHAR(hwport, (UCHAR)(divisorlatch & 0xff));
//
// Set LCR to 3. (3 is a magic number in the original assembler)
//
hwport = Port->Address;
hwport += COM_LCR;
WRITE_PORT_UCHAR(hwport, 3);
//
// Remember the baud rate
//
Port->Baud = Rate;
}
USHORT
CpQueryBaud (
PCPPORT Port
)
/*++
Routine Description:
Return the last value baud rate was set to.
Arguments:
Port - address of cpport object which describes the hw port of interest.
Return Value:
Baud rate. 0 = none has been set.
--*/
{
return (USHORT) Port->Baud;
}
VOID
CpSendModemString (
PCPPORT Port,
IN PUCHAR String
)
/*++
Routine Description:
Sends a command string to the modem.
This is down in order to aid the modem in determining th
baud rate the local connect is at.
Arguments:
Port - Address of CPPORT
String - String to send to modem
--*/
{
static ULONG Delay;
TIME_FIELDS CurrentTime;
UCHAR i;
ULONG l;
if (Port->Flags & PORT_SENDINGSTRING)
return ;
Port->Flags |= PORT_SENDINGSTRING;
if (!Delay) {
// see how long 1 second is
HalQueryRealTimeClock (&CurrentTime);
l = CurrentTime.Second;
while (l == (ULONG) CurrentTime.Second) {
CpReadLsr(Port, 0);
HalQueryRealTimeClock (&CurrentTime);
Delay++;
}
Delay = Delay / 3;
}
l = Delay;
while (*String) {
HalQueryRealTimeClock (&CurrentTime);
i = CpReadLsr (Port, 0);
if (i & COM_OUTRDY) {
if ((--l) == 0) {
WRITE_PORT_UCHAR(Port->Address+COM_DAT, *String);
String++;
l = Delay;
}
}
if (i & COM_DATRDY)
READ_PORT_UCHAR(Port->Address + COM_DAT);
}
Port->Flags &= ~PORT_SENDINGSTRING;
}
UCHAR
CpReadLsr (
PCPPORT Port,
UCHAR waiting
)
/*++
Routine Description:
Read LSR byte from specified port. If HAL owns port & display
it will also cause a debug status to be kept up to date.
Handles entering & exiting modem control mode for debugger.
Arguments:
Port - Address of CPPORT
Returns:
Byte read from port
--*/
{
static UCHAR ringflag = 0;
static UCHAR diagout[3];
static ULONG diagmsg[3] = { 'TRP ', 'LVO ', 'MRF ' };
static UCHAR ModemString[] = "\n\rAT\n\r";
TIME_FIELDS CurrentTime;
UCHAR lsr, msr, i;
ULONG diagstr[12];
lsr = READ_PORT_UCHAR(Port->Address + COM_LSR);
if (lsr & COM_PE)
diagout[0] = 8; // Parity error
if (lsr & COM_OE)
diagout[1] = 8; // Overflow error
if (lsr & COM_FE)
diagout[2] = 8; // Framing error
if (lsr & waiting) {
LastLsr = ~COM_DATRDY | (lsr & COM_DATRDY);
return lsr;
}
msr = READ_PORT_UCHAR (Port->Address + COM_MSR);
if (Port->Flags & PORT_MODEMCONTROL) {
if (msr & SERIAL_MSR_DCD) {
//
// In modem control mode with carrier detect
// Reset carrier lost time
//
Port->Flags |= PORT_NOCDLTIME | PORT_MDM_CD;
} else {
//
// In modem control mode, but no carrier detect. After
// 60 seconds drop out of modem control mode
//
if (Port->Flags & PORT_NOCDLTIME) {
HalQueryRealTimeClock (&Port->CarrierLostTime);
Port->Flags &= ~PORT_NOCDLTIME;
ringflag = 0;
}
HalQueryRealTimeClock (&CurrentTime);
if (CurrentTime.Minute != Port->CarrierLostTime.Minute &&
CurrentTime.Second >= Port->CarrierLostTime.Second) {
//
// It's been at least 60 seconds - drop out of
// modem control mode until next RI
//
Port->Flags &= ~PORT_MODEMCONTROL;
CpSendModemString (Port, ModemString);
}
if (Port->Flags & PORT_MDM_CD) {
//
// We had a connection - if it's the connection has been
// down for a few seconds, then send a string to the modem
//
if (CurrentTime.Second < Port->CarrierLostTime.Second)
CurrentTime.Second += 60;
if (CurrentTime.Second > Port->CarrierLostTime.Second + 10) {
Port->Flags &= ~PORT_MDM_CD;
CpSendModemString (Port, ModemString);
}
}
}
}
if ((lsr == LastLsr && msr == LastMsr) || !(Port->Flags & PORT_SAVED))
return lsr;
ringflag |= (msr & SERIAL_MSR_RI) ? 1 : 2;
if (ringflag == 3) {
//
// The ring indicate line has toggled
// Use modem control from now on
//
ringflag = 0;
Port->Flags |= PORT_MODEMCONTROL | PORT_NOCDLTIME;
Port->Flags &= ~PORT_MDM_CD;
if (Port->Flags & PORT_DEFAULTRATE && Port->Baud != BD_9600) {
//
// Baud rate was never specified switch
// to 9600 baud as default (for modem usage).
//
HalDisplayString (MSG_DEBUG_9600);
CpSetBaud (Port, BD_9600);
//Port->Flags |= PORT_DISBAUD;
}
}
for (i=0; i < 3; i++) {
if (diagout[i]) {
diagout[i]--;
diagstr[10-i] = diagmsg[i];
} else {
diagstr[10-i] = ' ';
}
}
diagstr[7] = (LastLsr & COM_DATRDY) ? 'VCR ' : ' ';
diagstr[6] = (lsr & COM_OUTRDY) ? ' ' : 'DNS ';
diagstr[5] = (msr & 0x10) ? 'STC ' : ' ';
diagstr[4] = (msr & 0x20) ? 'RSD ' : ' ';
diagstr[3] = (msr & 0x40) ? ' IR ' : ' ';
diagstr[2] = (msr & 0x80) ? ' DC ' : ' ';
diagstr[1] = (Port->Flags & PORT_MODEMCONTROL) ? 'MDM ' : ' ';
diagstr[0] = ' ';
#if 0
if (Port->Flags & PORT_DISBAUD) {
switch (Port->Baud) {
case BD_9600: diagstr[0] = ' 69 '; break;
case BD_14400: diagstr[0] = 'K41 '; break;
case BD_19200: diagstr[0] = 'K91 '; break;
case BD_56000: diagstr[0] = 'K65 '; break;
}
}
#endif
HalpDisplayDebugStatus ((PUCHAR) diagstr, 11*4);
LastLsr = lsr;
LastMsr = msr;
return lsr;
}
VOID
CpPutByte (
PCPPORT Port,
UCHAR Byte
)
/*++
Routine Description:
Write a byte out to the specified com port.
Arguments:
Port - Address of CPPORT object
Byte - data to emit
--*/
{
UCHAR msr, lsr;
//
// If modem control, make sure DSR, CTS and CD are all set before
// sending any data.
//
while ((Port->Flags & PORT_MODEMCONTROL) &&
(msr = READ_PORT_UCHAR(Port->Address + COM_MSR) & MS_DSRCTSCD) != MS_DSRCTSCD) {
//
// If no CD, and there's a charactor ready, eat it
//
lsr = CpReadLsr (Port, 0);
if ((msr & MS_CD) == 0 && (lsr & COM_DATRDY) == COM_DATRDY) {
READ_PORT_UCHAR(Port->Address + COM_DAT);
}
}
//
// Wait for port to not be busy
//
while (!(CpReadLsr(Port, COM_OUTRDY) & COM_OUTRDY)) ;
//
// Send the byte
//
WRITE_PORT_UCHAR(Port->Address + COM_DAT, Byte);
}
USHORT
CpGetByte (
PCPPORT Port,
PUCHAR Byte,
BOOLEAN WaitForByte
)
/*++
Routine Description:
Fetch a byte and return it.
Arguments:
Port - address of port object that describes hw port
Byte - address of variable to hold the result
WaitForByte - flag indicates wait for byte or not.
Return Value:
CP_GET_SUCCESS if data returned.
CP_GET_NODATA if no data available, but no error.
CP_GET_ERROR if error (overrun, parity, etc.)
--*/
{
UCHAR lsr;
UCHAR value;
ULONG limitcount;
//
// Make sure DTR and CTS are set
//
// (What does CTS have to do with reading from a full duplex line???)
//
// Check to make sure the CPPORT we were passed has been initialized.
// (The only time it won't be initialized is when the kernel debugger
// is disabled, in which case we just return.)
//
if (Port->Address == NULL) {
return(CP_GET_NODATA);
}
limitcount = WaitForByte ? TIMEOUT_COUNT : 1;
while (limitcount != 0) {
limitcount--;
lsr = CpReadLsr(Port, COM_DATRDY);
if ((lsr & COM_DATRDY) == COM_DATRDY) {
//
// Check for errors
//
if (lsr & (COM_FE | COM_PE | COM_OE)) {
*Byte = 0;
return(CP_GET_ERROR);
}
//
// fetch the byte
//
value = READ_PORT_UCHAR(Port->Address + COM_DAT);
if (Port->Flags & PORT_MODEMCONTROL) {
//
// Using modem control. If no CD, then skip this byte.
//
if ((READ_PORT_UCHAR(Port->Address + COM_MSR) & MS_CD) == 0) {
continue;
}
}
*Byte = value & (UCHAR)0xff;
return CP_GET_SUCCESS;
}
}
LastLsr = 0;
CpReadLsr (Port, 0);
return CP_GET_NODATA;
}
BOOLEAN
CpDoesPortExist(
IN PUCHAR Address
)
/*++
Routine Description:
This routine will attempt to place the port into its
diagnostic mode. If it does it will twiddle a bit in
the modem control register. If the port exists this
twiddling should show up in the modem status register.
NOTE: This routine must be called before the device is
enabled for interrupts, this includes setting the
output2 bit in the modem control register.
This is blatantly stolen from TonyE's code in ntos\dd\serial\serial.c.
Arguments:
Address - address of hw port.
Return Value:
TRUE - Port exists. Party on.
FALSE - Port doesn't exist. Don't use it.
--*/
{
UCHAR OldModemStatus;
UCHAR ModemStatus;
BOOLEAN ReturnValue = TRUE;
//
// Save the old value of the modem control register.
//
OldModemStatus = READ_PORT_UCHAR(Address+COM_MCR);
//
// Set the port into diagnostic mode.
//
WRITE_PORT_UCHAR(
Address+COM_MCR,
SERIAL_MCR_LOOP
);
//
// Bang on it again to make sure that all the lower bits
// are clear.
//
WRITE_PORT_UCHAR(
Address+COM_MCR,
SERIAL_MCR_LOOP
);
//
// Read the modem status register. The high for bits should
// be clear.
//
ModemStatus = READ_PORT_UCHAR(Address+COM_MSR);
if (ModemStatus & (SERIAL_MSR_CTS | SERIAL_MSR_DSR |
SERIAL_MSR_RI | SERIAL_MSR_DCD)) {
ReturnValue = FALSE;
goto AllDone;
}
//
// So far so good. Now turn on OUT1 in the modem control register
// and this should turn on ring indicator in the modem status register.
//
WRITE_PORT_UCHAR(
Address+COM_MCR,
(SERIAL_MCR_OUT1 | SERIAL_MCR_LOOP)
);
ModemStatus = READ_PORT_UCHAR(Address+COM_MSR);
if (!(ModemStatus & SERIAL_MSR_RI)) {
ReturnValue = FALSE;
goto AllDone;
}
AllDone: ;
//
// Put the modem control back into a clean state.
//
WRITE_PORT_UCHAR(
Address+COM_MCR,
OldModemStatus
);
return ReturnValue;
}
