sys/arch/i386/stand/lib/comio_direct.c

   1 /*      $NetBSD: comio_direct.c,v 1.10 2008/12/14 18:46:33 christos Exp $       */
   2
   3 /*-
   4  * Copyright (c) 1993, 1994, 1995, 1996, 1997
   5  *      Charles M. Hannum.  All rights reserved.
   6  *
   7  * Taken from sys/dev/isa/com.c and integrated into standalone boot
   8  * programs by Martin Husemann.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by Charles M. Hannum.
  21  * 4. The name of the author may not be used to endorse or promote products
  22  *    derived from this software without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  27  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  28  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  29  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  30  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  31  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  32  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  33  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 /*
  37  * Copyright (c) 1991 The Regents of the University of California.
  38  * All rights reserved.
  39  *
  40  * Redistribution and use in source and binary forms, with or without
  41  * modification, are permitted provided that the following conditions
  42  * are met:
  43  * 1. Redistributions of source code must retain the above copyright
  44  *    notice, this list of conditions and the following disclaimer.
  45  * 2. Redistributions in binary form must reproduce the above copyright
  46  *    notice, this list of conditions and the following disclaimer in the
  47  *    documentation and/or other materials provided with the distribution.
  48  * 3. Neither the name of the University nor the names of its contributors
  49  *    may be used to endorse or promote products derived from this software
  50  *    without specific prior written permission.
  51  *
  52  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  62  * SUCH DAMAGE.
  63  *
  64  *      @(#)com.c       7.5 (Berkeley) 5/16/91
  65  */
  66
  67 #include <sys/types.h>
  68 #include <lib/libsa/stand.h>
  69 #include <machine/pio.h>
  70 #include <dev/ic/comreg.h>
  71 #include "comio_direct.h"
  72 #include "libi386.h"
  73
  74 /* preread buffer for xon/xoff handling */
  75 #define XON     0x11
  76 #define XOFF    0x13
  77 #define SERBUFSIZE      16
  78 static u_char serbuf[SERBUFSIZE];
  79 static int serbuf_read = 0;
  80 static int serbuf_write = 0;
  81 static int stopped = 0;
  82
  83 #define ISSET(t,f)      ((t) & (f))
  84
  85 #define divrnd(n, q)    (((n)*2/(q)+1)/2)       /* divide and round off */
  86 #define RATE_9600 divrnd((COM_FREQ / 16), 9600)
  87
  88 /*
  89  * calculate divisor for a given speed
  90  */
  91 static int
  92 comspeed(long speed)
  93 {
  94         int x, err;
  95
  96         if (speed <= 0)
  97                 speed = 9600;
  98         x = divrnd((COM_FREQ / 16), speed);
  99         if (x <= 0)
 100                 return RATE_9600;
 101         err = divrnd((COM_FREQ / 16) * 1000, speed * x) - 1000;
 102         if (err < 0)
 103                 err = -err;
 104         if (err > COM_TOLERANCE)
 105                 return RATE_9600;
 106         return x;
 107 }
 108
 109 /*
 110  * get a character
 111  */
 112 int
 113 comgetc_d(int combase)
 114 {
 115         u_char stat, c;
 116
 117         if (serbuf_read != serbuf_write) {
 118                 c = serbuf[serbuf_read++];
 119                 if (serbuf_read >= SERBUFSIZE)
 120                         serbuf_read = 0;
 121                 return c;
 122         }
 123
 124         for (;;) {
 125                 while (!ISSET(stat = inb(combase + com_lsr), LSR_RXRDY))
 126                         continue;
 127                 c = inb(combase + com_data);
 128                 inb(combase + com_iir);
 129                 if (c != XOFF) {
 130                         stopped = 0;
 131                         break;  /* got a real char, deliver it... */
 132                 }
 133                 stopped = 1;
 134         }
 135         return c;
 136 }
 137
 138 /*
 139  * output a character, return nonzero on success
 140  */
 141 int
 142 computc_d(int c, int combase)
 143 {
 144         u_char stat;
 145         int timo;
 146
 147         /* check for old XOFF */
 148         while (stopped)
 149                 comgetc_d(combase);     /* wait for XON */
 150
 151         /* check for new XOFF */
 152         if (comstatus_d(combase)) {
 153                 int c = comgetc_d(combase);     /* XOFF handled in comgetc_d */
 154                 /* stuff char into preread buffer */
 155                 serbuf[serbuf_write++] = c;
 156                 if (serbuf_write >= SERBUFSIZE)
 157                         serbuf_write = 0;
 158         }
 159
 160         /* wait for any pending transmission to finish */
 161         timo = 50000;
 162         while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY)
 163             && --timo)
 164                 continue;
 165         if (timo == 0) return 0;
 166         outb(combase + com_data, c);
 167         /* wait for this transmission to complete */
 168         timo = 1500000;
 169         while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY)
 170             && --timo)
 171                 continue;
 172         if (timo == 0) return 0;
 173         /* clear any interrupts generated by this transmission */
 174         inb(combase + com_iir);
 175
 176         return 1;
 177 }
 178
 179 /*
 180  * Initialize UART to known state.
 181  */
 182 int
 183 cominit_d(int combase, int speed)
 184 {
 185         int rate, err;
 186
 187         serbuf_read = 0;
 188         serbuf_write = 0;
 189
 190         outb(combase + com_cfcr, LCR_DLAB);
 191         if (speed == 0) {
 192                 /* Try to determine the current baud rate */
 193                 rate = inb(combase + com_dlbl) | inb(combase + com_dlbh) << 8;
 194                 if (rate == 0)
 195                         rate = RATE_9600;
 196                 speed = divrnd((COM_FREQ / 16), rate);
 197                 err = speed - (speed + 150)/300 * 300;
 198                 speed -= err;
 199                 if (err < 0)
 200                         err = -err;
 201                 if (err > 50)
 202                         speed = 9600;
 203         }
 204         rate = comspeed(speed);
 205         outb(combase + com_dlbl, rate);
 206         outb(combase + com_dlbh, rate >> 8);
 207         outb(combase + com_cfcr, LCR_8BITS);
 208         outb(combase + com_mcr, MCR_DTR | MCR_RTS);
 209         outb(combase + com_fifo,
 210             FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
 211         outb(combase + com_ier, 0);
 212
 213         return speed;
 214 }
 215
 216 /*
 217  * return nonzero if input char available, do XON/XOFF handling
 218  */
 219 int
 220 comstatus_d(int combase)
 221 {
 222         /* check if any preread input is already there */
 223         if (serbuf_read != serbuf_write) return 1;
 224
 225         /* check for new stuff on the port */
 226         if (ISSET(inb(combase + com_lsr), LSR_RXRDY)) {
 227                 /* this could be XOFF, which we would swallow, so we can't
 228                    claim there is input available... */
 229                 int c = inb(combase + com_data);
 230                 inb(combase + com_iir);
 231                 if (c == XOFF) {
 232                         stopped = 1;
 233                 } else {
 234                         /* stuff char into preread buffer */
 235                         serbuf[serbuf_write++] = c;
 236                         if (serbuf_write >= SERBUFSIZE)
 237                                 serbuf_write = 0;
 238                         return 1;
 239                 }
 240         }
 241
 242         return 0;       /* nothing out there... */
 243 }