minix/sys/arch/i386/stand/lib/comio_direct.c
2012-02-09 18:48:13 +01:00

243 lines
7.1 KiB
C

/* $NetBSD: comio_direct.c,v 1.10 2008/12/14 18:46:33 christos Exp $ */
/*-
* Copyright (c) 1993, 1994, 1995, 1996, 1997
* Charles M. Hannum. All rights reserved.
*
* Taken from sys/dev/isa/com.c and integrated into standalone boot
* programs by Martin Husemann.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Charles M. Hannum.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 1991 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)com.c 7.5 (Berkeley) 5/16/91
*/
#include <sys/types.h>
#include <lib/libsa/stand.h>
#include <machine/pio.h>
#include <dev/ic/comreg.h>
#include "comio_direct.h"
#include "libi386.h"
/* preread buffer for xon/xoff handling */
#define XON 0x11
#define XOFF 0x13
#define SERBUFSIZE 16
static u_char serbuf[SERBUFSIZE];
static int serbuf_read = 0;
static int serbuf_write = 0;
static int stopped = 0;
#define ISSET(t,f) ((t) & (f))
#define divrnd(n, q) (((n)*2/(q)+1)/2) /* divide and round off */
#define RATE_9600 divrnd((COM_FREQ / 16), 9600)
/*
* calculate divisor for a given speed
*/
static int
comspeed(long speed)
{
int x, err;
if (speed <= 0)
speed = 9600;
x = divrnd((COM_FREQ / 16), speed);
if (x <= 0)
return RATE_9600;
err = divrnd((COM_FREQ / 16) * 1000, speed * x) - 1000;
if (err < 0)
err = -err;
if (err > COM_TOLERANCE)
return RATE_9600;
return x;
}
/*
* get a character
*/
int
comgetc_d(int combase)
{
u_char stat, c;
if (serbuf_read != serbuf_write) {
c = serbuf[serbuf_read++];
if (serbuf_read >= SERBUFSIZE)
serbuf_read = 0;
return c;
}
for (;;) {
while (!ISSET(stat = inb(combase + com_lsr), LSR_RXRDY))
continue;
c = inb(combase + com_data);
inb(combase + com_iir);
if (c != XOFF) {
stopped = 0;
break; /* got a real char, deliver it... */
}
stopped = 1;
}
return c;
}
/*
* output a character, return nonzero on success
*/
int
computc_d(int c, int combase)
{
u_char stat;
int timo;
/* check for old XOFF */
while (stopped)
comgetc_d(combase); /* wait for XON */
/* check for new XOFF */
if (comstatus_d(combase)) {
int c = comgetc_d(combase); /* XOFF handled in comgetc_d */
/* stuff char into preread buffer */
serbuf[serbuf_write++] = c;
if (serbuf_write >= SERBUFSIZE)
serbuf_write = 0;
}
/* wait for any pending transmission to finish */
timo = 50000;
while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY)
&& --timo)
continue;
if (timo == 0) return 0;
outb(combase + com_data, c);
/* wait for this transmission to complete */
timo = 1500000;
while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY)
&& --timo)
continue;
if (timo == 0) return 0;
/* clear any interrupts generated by this transmission */
inb(combase + com_iir);
return 1;
}
/*
* Initialize UART to known state.
*/
int
cominit_d(int combase, int speed)
{
int rate, err;
serbuf_read = 0;
serbuf_write = 0;
outb(combase + com_cfcr, LCR_DLAB);
if (speed == 0) {
/* Try to determine the current baud rate */
rate = inb(combase + com_dlbl) | inb(combase + com_dlbh) << 8;
if (rate == 0)
rate = RATE_9600;
speed = divrnd((COM_FREQ / 16), rate);
err = speed - (speed + 150)/300 * 300;
speed -= err;
if (err < 0)
err = -err;
if (err > 50)
speed = 9600;
}
rate = comspeed(speed);
outb(combase + com_dlbl, rate);
outb(combase + com_dlbh, rate >> 8);
outb(combase + com_cfcr, LCR_8BITS);
outb(combase + com_mcr, MCR_DTR | MCR_RTS);
outb(combase + com_fifo,
FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
outb(combase + com_ier, 0);
return speed;
}
/*
* return nonzero if input char available, do XON/XOFF handling
*/
int
comstatus_d(int combase)
{
/* check if any preread input is already there */
if (serbuf_read != serbuf_write) return 1;
/* check for new stuff on the port */
if (ISSET(inb(combase + com_lsr), LSR_RXRDY)) {
/* this could be XOFF, which we would swallow, so we can't
claim there is input available... */
int c = inb(combase + com_data);
inb(combase + com_iir);
if (c == XOFF) {
stopped = 1;
} else {
/* stuff char into preread buffer */
serbuf[serbuf_write++] = c;
if (serbuf_write >= SERBUFSIZE)
serbuf_write = 0;
return 1;
}
}
return 0; /* nothing out there... */
}