comio_direct.c revision 1.5
1 /* $NetBSD: comio_direct.c,v 1.5 2003/04/16 14:56:55 dsl 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. All advertising materials mentioning features or use of this software 49 * must display the following acknowledgement: 50 * This product includes software developed by the University of 51 * California, Berkeley and its contributors. 52 * 4. Neither the name of the University nor the names of its contributors 53 * may be used to endorse or promote products derived from this software 54 * without specific prior written permission. 55 * 56 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 57 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 58 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 59 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 60 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 61 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 62 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 63 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 64 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 65 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 66 * SUCH DAMAGE. 67 * 68 * @(#)com.c 7.5 (Berkeley) 5/16/91 69 */ 70 71 #include <sys/types.h> 72 #include <lib/libsa/stand.h> 73 #include <machine/pio.h> 74 #include <dev/ic/comreg.h> 75 #include "comio_direct.h" 76 #include "libi386.h" 77 78 static int comspeed __P((long speed)); 79 80 /* preread buffer for xon/xoff handling */ 81 #define XON 0x11 82 #define XOFF 0x13 83 #define SERBUFSIZE 16 84 static u_char serbuf[SERBUFSIZE]; 85 static int serbuf_read = 0; 86 static int serbuf_write = 0; 87 static int stopped = 0; 88 89 #define ISSET(t,f) ((t) & (f)) 90 91 /* 92 * calculate divisor for a given speed 93 */ 94 static int 95 comspeed(speed) 96 long speed; 97 { 98 #define divrnd(n, q) (((n)*2/(q)+1)/2) /* divide and round off */ 99 100 int x, err; 101 102 if (speed <= 0) 103 speed = 9600; 104 x = divrnd((COM_FREQ / 16), speed); 105 if (x <= 0) 106 return divrnd((COM_FREQ / 16), 9600); 107 err = divrnd((COM_FREQ / 16) * 1000, speed * x) - 1000; 108 if (err < 0) 109 err = -err; 110 if (err > COM_TOLERANCE) 111 return divrnd((COM_FREQ / 16), 9600); 112 return (x); 113 114 #undef divrnd(n, q) 115 } 116 117 /* 118 * get a character 119 */ 120 int 121 comgetc_d(combase) 122 int combase; 123 { 124 u_char stat, c; 125 126 if (serbuf_read != serbuf_write) { 127 c = serbuf[serbuf_read++]; 128 if (serbuf_read >= SERBUFSIZE) 129 serbuf_read = 0; 130 return c; 131 } 132 133 for (;;) { 134 while (!ISSET(stat = inb(combase + com_lsr), LSR_RXRDY)) 135 ; 136 c = inb(combase + com_data); 137 inb(combase + com_iir); 138 if (c != XOFF) { 139 stopped = 0; 140 break; /* got a real char, deliver it... */ 141 } 142 stopped = 1; 143 } 144 return (c); 145 } 146 147 /* 148 * output a character, return nonzero on success 149 */ 150 int 151 computc_d(c, combase) 152 int c; 153 int combase; 154 { 155 u_char stat; 156 register int timo; 157 158 /* check for old XOFF */ 159 while (stopped) 160 comgetc_d(combase); /* wait for XON */ 161 162 /* check for new XOFF */ 163 if (comstatus_d(combase)) { 164 int c = comgetc_d(combase); /* XOFF handled in comgetc_d */ 165 /* stuff char into preread buffer */ 166 serbuf[serbuf_write++] = c; 167 if (serbuf_write >= SERBUFSIZE) 168 serbuf_write = 0; 169 } 170 171 /* wait for any pending transmission to finish */ 172 timo = 50000; 173 while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY) 174 && --timo) 175 ; 176 if (timo == 0) return 0; 177 outb(combase + com_data, c); 178 /* wait for this transmission to complete */ 179 timo = 1500000; 180 while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY) 181 && --timo) 182 ; 183 if (timo == 0) return 0; 184 /* clear any interrupts generated by this transmission */ 185 inb(combase + com_iir); 186 187 return 1; 188 } 189 190 /* 191 * Initialize UART to known state. 192 */ 193 void 194 cominit_d(combase,speed) 195 int combase; 196 int speed; 197 { 198 int rate; 199 200 serbuf_read = 0; 201 serbuf_write = 0; 202 203 outb(combase + com_cfcr, LCR_DLAB); 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 } 213 214 /* 215 * return nonzero if input char available, do XON/XOFF handling 216 */ 217 int 218 comstatus_d(combase) 219 int combase; 220 { 221 /* check if any preread input is already there */ 222 if (serbuf_read != serbuf_write) return 1; 223 224 /* check for new stuff on the port */ 225 if (ISSET(inb(combase + com_lsr), LSR_RXRDY)) { 226 /* this could be XOFF, which we would swallow, so we can't 227 claim there is input available... */ 228 int c = inb(combase + com_data); 229 inb(combase + com_iir); 230 if (c == XOFF) { 231 stopped = 1; 232 } else { 233 /* stuff char into preread buffer */ 234 serbuf[serbuf_write++] = c; 235 if (serbuf_write >= SERBUFSIZE) 236 serbuf_write = 0; 237 return 1; 238 } 239 } 240 241 return 0; /* nothing out there... */ 242 } 243
Indexes created Tue Sep 23 23:09:58 GMT 2025