/* $NetBSD: comio_direct.c,v 1.12 2022/09/05 14:14:42 tsutsui 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 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 x = comgetc_d(combase); /* XOFF handled in comgetc_d */ /* stuff char into preread buffer */ serbuf[serbuf_write++] = x; 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... */ }
