comio_direct.c revision 1.5.2.3
1 /* $NetBSD: comio_direct.c,v 1.5.2.3 2004/09/21 13:17:10 skrll 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 static int comspeed __P((long speed)); 75 76 /* preread buffer for xon/xoff handling */ 77 #define XON 0x11 78 #define XOFF 0x13 79 #define SERBUFSIZE 16 80 static u_char serbuf[SERBUFSIZE]; 81 static int serbuf_read = 0; 82 static int serbuf_write = 0; 83 static int stopped = 0; 84 85 #define ISSET(t,f) ((t) & (f)) 86 87 /* 88 * calculate divisor for a given speed 89 */ 90 static int 91 comspeed(speed) 92 long speed; 93 { 94 #define divrnd(n, q) (((n)*2/(q)+1)/2) /* divide and round off */ 95 96 int x, err; 97 98 if (speed <= 0) 99 speed = 9600; 100 x = divrnd((COM_FREQ / 16), speed); 101 if (x <= 0) 102 return divrnd((COM_FREQ / 16), 9600); 103 err = divrnd((COM_FREQ / 16) * 1000, speed * x) - 1000; 104 if (err < 0) 105 err = -err; 106 if (err > COM_TOLERANCE) 107 return divrnd((COM_FREQ / 16), 9600); 108 return (x); 109 110 #undef divrnd 111 } 112 113 /* 114 * get a character 115 */ 116 int 117 comgetc_d(combase) 118 int combase; 119 { 120 u_char stat, c; 121 122 if (serbuf_read != serbuf_write) { 123 c = serbuf[serbuf_read++]; 124 if (serbuf_read >= SERBUFSIZE) 125 serbuf_read = 0; 126 return c; 127 } 128 129 for (;;) { 130 while (!ISSET(stat = inb(combase + com_lsr), LSR_RXRDY)) 131 ; 132 c = inb(combase + com_data); 133 inb(combase + com_iir); 134 if (c != XOFF) { 135 stopped = 0; 136 break; /* got a real char, deliver it... */ 137 } 138 stopped = 1; 139 } 140 return (c); 141 } 142 143 /* 144 * output a character, return nonzero on success 145 */ 146 int 147 computc_d(c, combase) 148 int c; 149 int combase; 150 { 151 u_char stat; 152 register int timo; 153 154 /* check for old XOFF */ 155 while (stopped) 156 comgetc_d(combase); /* wait for XON */ 157 158 /* check for new XOFF */ 159 if (comstatus_d(combase)) { 160 int c = comgetc_d(combase); /* XOFF handled in comgetc_d */ 161 /* stuff char into preread buffer */ 162 serbuf[serbuf_write++] = c; 163 if (serbuf_write >= SERBUFSIZE) 164 serbuf_write = 0; 165 } 166 167 /* wait for any pending transmission to finish */ 168 timo = 50000; 169 while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY) 170 && --timo) 171 ; 172 if (timo == 0) return 0; 173 outb(combase + com_data, c); 174 /* wait for this transmission to complete */ 175 timo = 1500000; 176 while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY) 177 && --timo) 178 ; 179 if (timo == 0) return 0; 180 /* clear any interrupts generated by this transmission */ 181 inb(combase + com_iir); 182 183 return 1; 184 } 185 186 /* 187 * Initialize UART to known state. 188 */ 189 void 190 cominit_d(combase,speed) 191 int combase; 192 int speed; 193 { 194 int rate; 195 196 serbuf_read = 0; 197 serbuf_write = 0; 198 199 outb(combase + com_cfcr, LCR_DLAB); 200 rate = comspeed(speed); 201 outb(combase + com_dlbl, rate); 202 outb(combase + com_dlbh, rate >> 8); 203 outb(combase + com_cfcr, LCR_8BITS); 204 outb(combase + com_mcr, MCR_DTR | MCR_RTS); 205 outb(combase + com_fifo, 206 FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1); 207 outb(combase + com_ier, 0); 208 } 209 210 /* 211 * return nonzero if input char available, do XON/XOFF handling 212 */ 213 int 214 comstatus_d(combase) 215 int combase; 216 { 217 /* check if any preread input is already there */ 218 if (serbuf_read != serbuf_write) return 1; 219 220 /* check for new stuff on the port */ 221 if (ISSET(inb(combase + com_lsr), LSR_RXRDY)) { 222 /* this could be XOFF, which we would swallow, so we can't 223 claim there is input available... */ 224 int c = inb(combase + com_data); 225 inb(combase + com_iir); 226 if (c == XOFF) { 227 stopped = 1; 228 } else { 229 /* stuff char into preread buffer */ 230 serbuf[serbuf_write++] = c; 231 if (serbuf_write >= SERBUFSIZE) 232 serbuf_write = 0; 233 return 1; 234 } 235 } 236 237 return 0; /* nothing out there... */ 238 } 239
Indexes created Fri Oct 03 02:09:57 GMT 2025