1 /* $NetBSD: comio_direct.c,v 1.12 2022/09/05 14:14:42 tsutsui 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 divrnd(n, q) (((n)*2/(q)+1)/2) /* divide and round off */ 84 #define RATE_9600 divrnd((COM_FREQ / 16), 9600) 85 86 /* 87 * calculate divisor for a given speed 88 */ 89 static int 90 comspeed(long speed) 91 { 92 int x, err; 93 94 if (speed <= 0) 95 speed = 9600; 96 x = divrnd((COM_FREQ / 16), speed); 97 if (x <= 0) 98 return RATE_9600; 99 err = divrnd((COM_FREQ / 16) * 1000, speed * x) - 1000; 100 if (err < 0) 101 err = -err; 102 if (err > COM_TOLERANCE) 103 return RATE_9600; 104 return x; 105 } 106 107 /* 108 * get a character 109 */ 110 int 111 comgetc_d(int combase) 112 { 113 u_char stat, c; 114 115 if (serbuf_read != serbuf_write) { 116 c = serbuf[serbuf_read++]; 117 if (serbuf_read >= SERBUFSIZE) 118 serbuf_read = 0; 119 return c; 120 } 121 122 for (;;) { 123 while (!ISSET(stat = inb(combase + com_lsr), LSR_RXRDY)) 124 continue; 125 c = inb(combase + com_data); 126 inb(combase + com_iir); 127 if (c != XOFF) { 128 stopped = 0; 129 break; /* got a real char, deliver it... */ 130 } 131 stopped = 1; 132 } 133 return c; 134 } 135 136 /* 137 * output a character, return nonzero on success 138 */ 139 int 140 computc_d(int c, int combase) 141 { 142 u_char stat; 143 int timo; 144 145 /* check for old XOFF */ 146 while (stopped) 147 comgetc_d(combase); /* wait for XON */ 148 149 /* check for new XOFF */ 150 if (comstatus_d(combase)) { 151 int x = comgetc_d(combase); /* XOFF handled in comgetc_d */ 152 /* stuff char into preread buffer */ 153 serbuf[serbuf_write++] = x; 154 if (serbuf_write >= SERBUFSIZE) 155 serbuf_write = 0; 156 } 157 158 /* wait for any pending transmission to finish */ 159 timo = 50000; 160 while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY) 161 && --timo) 162 continue; 163 if (timo == 0) return 0; 164 outb(combase + com_data, c); 165 /* wait for this transmission to complete */ 166 timo = 1500000; 167 while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY) 168 && --timo) 169 continue; 170 if (timo == 0) return 0; 171 /* clear any interrupts generated by this transmission */ 172 inb(combase + com_iir); 173 174 return 1; 175 } 176 177 /* 178 * Initialize UART to known state. 179 */ 180 int 181 cominit_d(int combase, int speed) 182 { 183 int rate, err; 184 185 serbuf_read = 0; 186 serbuf_write = 0; 187 188 outb(combase + com_cfcr, LCR_DLAB); 189 if (speed == 0) { 190 /* Try to determine the current baud rate */ 191 rate = inb(combase + com_dlbl) | inb(combase + com_dlbh) << 8; 192 if (rate == 0) 193 rate = RATE_9600; 194 speed = divrnd((COM_FREQ / 16), rate); 195 err = speed - (speed + 150)/300 * 300; 196 speed -= err; 197 if (err < 0) 198 err = -err; 199 if (err > 50) 200 speed = 9600; 201 } 202 rate = comspeed(speed); 203 outb(combase + com_dlbl, rate); 204 outb(combase + com_dlbh, rate >> 8); 205 outb(combase + com_cfcr, LCR_8BITS); 206 outb(combase + com_mcr, MCR_DTR | MCR_RTS); 207 outb(combase + com_fifo, 208 FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1); 209 outb(combase + com_ier, 0); 210 211 return speed; 212 } 213 214 /* 215 * return nonzero if input char available, do XON/XOFF handling 216 */ 217 int 218 comstatus_d(int combase) 219 { 220 /* check if any preread input is already there */ 221 if (serbuf_read != serbuf_write) return 1; 222 223 /* check for new stuff on the port */ 224 if (ISSET(inb(combase + com_lsr), LSR_RXRDY)) { 225 /* this could be XOFF, which we would swallow, so we can't 226 claim there is input available... */ 227 int c = inb(combase + com_data); 228 inb(combase + com_iir); 229 if (c == XOFF) { 230 stopped = 1; 231 } else { 232 /* stuff char into preread buffer */ 233 serbuf[serbuf_write++] = c; 234 if (serbuf_write >= SERBUFSIZE) 235 serbuf_write = 0; 236 return 1; 237 } 238 } 239 240 return 0; /* nothing out there... */ 241 } 242
Indexes created Sun Sep 21 20:09:37 GMT 2025