comio_direct.c revision 1.3
1 /* $NetBSD: comio_direct.c,v 1.3 1998/01/05 07:02:58 perry 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 77 static int comspeed __P((long speed)); 78 79 /* preread buffer for xon/xoff handling */ 80 #define XON 0x11 81 #define XOFF 0x13 82 #define SERBUFSIZE 16 83 static u_char serbuf[SERBUFSIZE]; 84 static int serbuf_read = 0; 85 static int serbuf_write = 0; 86 static int stopped = 0; 87 88 #define ISSET(t,f) ((t) & (f)) 89 90 /* 91 * calculate divisor for a given speed 92 */ 93 static int 94 comspeed(speed) 95 long speed; 96 { 97 #define divrnd(n, q) (((n)*2/(q)+1)/2) /* divide and round off */ 98 99 int x, err; 100 101 #if 0 102 if (speed == 0) 103 return (0); 104 #endif 105 if (speed <= 0) 106 return (-1); 107 x = divrnd((COM_FREQ / 16), speed); 108 if (x <= 0) 109 return (-1); 110 err = divrnd((COM_FREQ / 16) * 1000, speed * x) - 1000; 111 if (err < 0) 112 err = -err; 113 if (err > COM_TOLERANCE) 114 return (-1); 115 return (x); 116 117 #undef divrnd(n, q) 118 } 119 120 /* 121 * get a character 122 */ 123 int 124 comgetc_d(combase) 125 int combase; 126 { 127 u_char stat, c; 128 129 if (serbuf_read != serbuf_write) { 130 c = serbuf[serbuf_read++]; 131 if (serbuf_read >= SERBUFSIZE) 132 serbuf_read = 0; 133 return c; 134 } 135 136 for (;;) { 137 while (!ISSET(stat = inb(combase + com_lsr), LSR_RXRDY)) 138 ; 139 c = inb(combase + com_data); 140 inb(combase + com_iir); 141 if (c != XOFF) { 142 stopped = 0; 143 break; /* got a real char, deliver it... */ 144 } 145 stopped = 1; 146 } 147 return (c); 148 } 149 150 /* 151 * output a character, return nonzero on success 152 */ 153 int 154 computc_d(c, combase) 155 int c; 156 int combase; 157 { 158 u_char stat; 159 register int timo; 160 161 /* check for old XOFF */ 162 while (stopped) 163 comgetc_d(combase); /* wait for XON */ 164 165 /* check for new XOFF */ 166 if (comstatus_d(combase)) { 167 int c = comgetc_d(combase); /* XOFF handled in comgetc_d */ 168 /* stuff char into preread buffer */ 169 serbuf[serbuf_write++] = c; 170 if (serbuf_write >= SERBUFSIZE) 171 serbuf_write = 0; 172 } 173 174 /* wait for any pending transmission to finish */ 175 timo = 50000; 176 while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY) 177 && --timo) 178 ; 179 if (timo == 0) return 0; 180 outb(combase + com_data, c); 181 /* wait for this transmission to complete */ 182 timo = 1500000; 183 while (!ISSET(stat = inb(combase + com_lsr), LSR_TXRDY) 184 && --timo) 185 ; 186 if (timo == 0) return 0; 187 /* clear any interrupts generated by this transmission */ 188 inb(combase + com_iir); 189 190 return 1; 191 } 192 193 /* 194 * Initialize UART to known state. 195 */ 196 void 197 cominit_d(combase) 198 int combase; 199 { 200 int rate; 201 202 serbuf_read = 0; 203 serbuf_write = 0; 204 205 outb(combase + com_cfcr, LCR_DLAB); 206 #ifdef CONSPEED 207 rate = comspeed(CONSPEED); 208 #else 209 rate = comspeed(9600); 210 #endif 211 outb(combase + com_dlbl, rate); 212 outb(combase + com_dlbh, rate >> 8); 213 outb(combase + com_cfcr, LCR_8BITS); 214 outb(combase + com_mcr, 0); 215 outb(combase + com_fifo, 216 FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1); 217 outb(combase + com_ier, 0); 218 } 219 220 /* 221 * return nonzero if input char available, do XON/XOFF handling 222 */ 223 int 224 comstatus_d(combase) 225 int combase; 226 { 227 /* check if any preread input is already there */ 228 if (serbuf_read != serbuf_write) return 1; 229 230 /* check for new stuff on the port */ 231 if (ISSET(inb(combase + com_lsr), LSR_RXRDY)) { 232 /* this could be XOFF, which we would swallow, so we can't 233 claim there is input available... */ 234 int c = inb(combase + com_data); 235 inb(combase + com_iir); 236 if (c == XOFF) { 237 stopped = 1; 238 } else { 239 /* stuff char into preread buffer */ 240 serbuf[serbuf_write++] = c; 241 if (serbuf_write >= SERBUFSIZE) 242 serbuf_write = 0; 243 return 1; 244 } 245 } 246 247 return 0; /* nothing out there... */ 248 } 249
Indexes created Tue Sep 23 22:09:46 GMT 2025