comio_direct.c revision 1.2
1 /*- 2 * Copyright (c) 1993, 1994, 1995, 1996, 1997 3 * Charles M. Hannum. All rights reserved. 4 * 5 * Taken from sys/dev/isa/com.c and integrated into standalone boot 6 * programs by Martin Husemann. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by Charles M. Hannum. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 1991 The Regents of the University of California. 36 * All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. All advertising materials mentioning features or use of this software 47 * must display the following acknowledgement: 48 * This product includes software developed by the University of 49 * California, Berkeley and its contributors. 50 * 4. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)com.c 7.5 (Berkeley) 5/16/91 67 */ 68 69 #include <sys/types.h> 70 #include <lib/libsa/stand.h> 71 #include <machine/pio.h> 72 #include <dev/ic/comreg.h> 73 #include "comio_direct.h" 74 75 static int comspeed __P((long speed)); 76 77 /* preread buffer for xon/xoff handling */ 78 #define XON 0x11 79 #define XOFF 0x13 80 #define SERBUFSIZE 16 81 static u_char serbuf[SERBUFSIZE]; 82 static int serbuf_read = 0; 83 static int serbuf_write = 0; 84 static int stopped = 0; 85 86 #define ISSET(t,f) ((t) & (f)) 87 88 /* 89 * calculate divisor for a given speed 90 */ 91 static int 92 comspeed(speed) 93 long speed; 94 { 95 #define divrnd(n, q) (((n)*2/(q)+1)/2) /* divide and round off */ 96 97 int x, err; 98 99 #if 0 100 if (speed == 0) 101 return (0); 102 #endif 103 if (speed <= 0) 104 return (-1); 105 x = divrnd((COM_FREQ / 16), speed); 106 if (x <= 0) 107 return (-1); 108 err = divrnd((COM_FREQ / 16) * 1000, speed * x) - 1000; 109 if (err < 0) 110 err = -err; 111 if (err > COM_TOLERANCE) 112 return (-1); 113 return (x); 114 115 #undef divrnd(n, q) 116 } 117 118 /* 119 * get a character 120 */ 121 int 122 comgetc_d(combase) 123 int combase; 124 { 125 u_char stat, c; 126 127 if (serbuf_read != serbuf_write) { 128 c = serbuf[serbuf_read++]; 129 if (serbuf_read >= SERBUFSIZE) 130 serbuf_read = 0; 131 return c; 132 } 133 134 for (;;) { 135 while (!ISSET(stat = inb(combase + com_lsr), LSR_RXRDY)) 136 ; 137 c = inb(combase + com_data); 138 inb(combase + com_iir); 139 if (c != XOFF) { 140 stopped = 0; 141 break; /* got a real char, deliver it... */ 142 } 143 stopped = 1; 144 } 145 return (c); 146 } 147 148 /* 149 * output a character, return nonzero on success 150 */ 151 int 152 computc_d(c, combase) 153 int c; 154 int combase; 155 { 156 u_char stat; 157 register int timo; 158 159 /* check for old XOFF */ 160 while (stopped) 161 comgetc_d(combase); /* wait for XON */ 162 163 /* check for new XOFF */ 164 if (comstatus_d(combase)) { 165 int c = comgetc_d(combase); /* XOFF handled in comgetc_d */ 166 /* stuff char into preread buffer */ 167 serbuf[serbuf_write++] = c; 168 if (serbuf_write >= SERBUFSIZE) 169 serbuf_write = 0; 170 } 171 172 /* wait for any pending transmission to finish */ 173 timo = 50000; 174 while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY) 175 && --timo) 176 ; 177 if (timo == 0) return 0; 178 outb(combase + com_data, c); 179 /* wait for this transmission to complete */ 180 timo = 1500000; 181 while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY) 182 && --timo) 183 ; 184 if (timo == 0) return 0; 185 /* clear any interrupts generated by this transmission */ 186 inb(combase + com_iir); 187 188 return 1; 189 } 190 191 /* 192 * Initialize UART to known state. 193 */ 194 void 195 cominit_d(combase) 196 int combase; 197 { 198 int rate; 199 200 serbuf_read = 0; 201 serbuf_write = 0; 202 203 outb(combase + com_cfcr, LCR_DLAB); 204 #ifdef CONSPEED 205 rate = comspeed(CONSPEED); 206 #else 207 rate = comspeed(9600); 208 #endif 209 outb(combase + com_dlbl, rate); 210 outb(combase + com_dlbh, rate >> 8); 211 outb(combase + com_cfcr, LCR_8BITS); 212 outb(combase + com_mcr, 0); 213 outb(combase + com_fifo, 214 FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1); 215 outb(combase + com_ier, 0); 216 } 217 218 /* 219 * return nonzero if input char available, do XON/XOFF handling 220 */ 221 int 222 comstatus_d(combase) 223 int combase; 224 { 225 /* check if any preread input is already there */ 226 if (serbuf_read != serbuf_write) return 1; 227 228 /* check for new stuff on the port */ 229 if (ISSET(inb(combase + com_lsr), LSR_RXRDY)) { 230 /* this could be XOFF, which we would swallow, so we can't 231 claim there is input available... */ 232 int c = inb(combase + com_data); 233 inb(combase + com_iir); 234 if (c == XOFF) { 235 stopped = 1; 236 } else { 237 /* stuff char into preread buffer */ 238 serbuf[serbuf_write++] = c; 239 if (serbuf_write >= SERBUFSIZE) 240 serbuf_write = 0; 241 return 1; 242 } 243 } 244 245 return 0; /* nothing out there... */ 246 } 247
Indexes created Mon Sep 22 21:09:42 GMT 2025