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 } 244