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