1/*-
2 * Copyright (c) 1998 Michael Smith (msmith@freebsd.org)
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26#include <sys/cdefs.h>
| 1/*-
2 * Copyright (c) 1998 Michael Smith (msmith@freebsd.org)
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26#include <sys/cdefs.h>
|
27__FBSDID("$FreeBSD: head/sys/boot/i386/libi386/comconsole.c 229435 2012-01-03 22:36:12Z kib $");
| 27__FBSDID("$FreeBSD: head/sys/boot/i386/libi386/comconsole.c 241300 2012-10-06 20:04:51Z avg $");
|
28
29#include <stand.h>
30#include <bootstrap.h>
31#include <machine/cpufunc.h>
32#include <dev/ic/ns16550.h>
33#include <dev/pci/pcireg.h>
34#include "libi386.h"
35
36#define COMC_FMT 0x3 /* 8N1 */
37#define COMC_TXWAIT 0x40000 /* transmit timeout */
38#define COMC_BPS(x) (115200 / (x)) /* speed to DLAB divisor */
39#define COMC_DIV2BPS(x) (115200 / (x)) /* DLAB divisor to speed */
40
41#ifndef COMPORT
42#define COMPORT 0x3f8
43#endif
44#ifndef COMSPEED
45#define COMSPEED 9600
46#endif
47
48static void comc_probe(struct console *cp);
49static int comc_init(int arg);
50static void comc_putchar(int c);
51static int comc_getchar(void);
52static int comc_getspeed(void);
53static void set_hw_console_hint(void);
54static int comc_ischar(void);
55static int comc_parseint(const char *string);
56static uint32_t comc_parse_pcidev(const char *string);
57static int comc_pcidev_set(struct env_var *ev, int flags,
58 const void *value);
59static int comc_pcidev_handle(uint32_t locator);
60static int comc_port_set(struct env_var *ev, int flags,
61 const void *value);
62static void comc_setup(int speed, int port);
63static int comc_speed_set(struct env_var *ev, int flags,
64 const void *value);
65
| 28
29#include <stand.h>
30#include <bootstrap.h>
31#include <machine/cpufunc.h>
32#include <dev/ic/ns16550.h>
33#include <dev/pci/pcireg.h>
34#include "libi386.h"
35
36#define COMC_FMT 0x3 /* 8N1 */
37#define COMC_TXWAIT 0x40000 /* transmit timeout */
38#define COMC_BPS(x) (115200 / (x)) /* speed to DLAB divisor */
39#define COMC_DIV2BPS(x) (115200 / (x)) /* DLAB divisor to speed */
40
41#ifndef COMPORT
42#define COMPORT 0x3f8
43#endif
44#ifndef COMSPEED
45#define COMSPEED 9600
46#endif
47
48static void comc_probe(struct console *cp);
49static int comc_init(int arg);
50static void comc_putchar(int c);
51static int comc_getchar(void);
52static int comc_getspeed(void);
53static void set_hw_console_hint(void);
54static int comc_ischar(void);
55static int comc_parseint(const char *string);
56static uint32_t comc_parse_pcidev(const char *string);
57static int comc_pcidev_set(struct env_var *ev, int flags,
58 const void *value);
59static int comc_pcidev_handle(uint32_t locator);
60static int comc_port_set(struct env_var *ev, int flags,
61 const void *value);
62static void comc_setup(int speed, int port);
63static int comc_speed_set(struct env_var *ev, int flags,
64 const void *value);
65
|
66static int comc_started;
| |
67static int comc_curspeed;
68static int comc_port = COMPORT;
69static uint32_t comc_locator;
70
71struct console comconsole = {
72 "comconsole",
73 "serial port",
74 0,
75 comc_probe,
76 comc_init,
77 comc_putchar,
78 comc_getchar,
79 comc_ischar
80};
81
82static void
83comc_probe(struct console *cp)
84{
85 char intbuf[16];
86 char *cons, *env;
87 int speed, port;
88 uint32_t locator;
89
| 66static int comc_curspeed;
67static int comc_port = COMPORT;
68static uint32_t comc_locator;
69
70struct console comconsole = {
71 "comconsole",
72 "serial port",
73 0,
74 comc_probe,
75 comc_init,
76 comc_putchar,
77 comc_getchar,
78 comc_ischar
79};
80
81static void
82comc_probe(struct console *cp)
83{
84 char intbuf[16];
85 char *cons, *env;
86 int speed, port;
87 uint32_t locator;
88
|
90 /* XXX check the BIOS equipment list? */
91 cp->c_flags |= (C_PRESENTIN | C_PRESENTOUT);
92
| |
93 if (comc_curspeed == 0) {
94 comc_curspeed = COMSPEED;
95 /*
96 * Assume that the speed was set by an earlier boot loader if
97 * comconsole is already the preferred console.
98 */
99 cons = getenv("console");
100 if ((cons != NULL && strcmp(cons, comconsole.c_name) == 0) ||
101 getenv("boot_multicons") != NULL) {
102 comc_curspeed = comc_getspeed();
103 }
104
105 env = getenv("comconsole_speed");
106 if (env != NULL) {
107 speed = comc_parseint(env);
108 if (speed > 0)
109 comc_curspeed = speed;
110 }
111
112 sprintf(intbuf, "%d", comc_curspeed);
113 unsetenv("comconsole_speed");
114 env_setenv("comconsole_speed", EV_VOLATILE, intbuf, comc_speed_set,
115 env_nounset);
116
117 env = getenv("comconsole_port");
118 if (env != NULL) {
119 port = comc_parseint(env);
120 if (port > 0)
121 comc_port = port;
122 }
123
124 sprintf(intbuf, "%d", comc_port);
125 unsetenv("comconsole_port");
126 env_setenv("comconsole_port", EV_VOLATILE, intbuf, comc_port_set,
127 env_nounset);
128
129 env = getenv("comconsole_pcidev");
130 if (env != NULL) {
131 locator = comc_parse_pcidev(env);
132 if (locator != 0)
133 comc_pcidev_handle(locator);
134 }
135
136 unsetenv("comconsole_pcidev");
137 env_setenv("comconsole_pcidev", EV_VOLATILE, env, comc_pcidev_set,
138 env_nounset);
139 }
| 89 if (comc_curspeed == 0) {
90 comc_curspeed = COMSPEED;
91 /*
92 * Assume that the speed was set by an earlier boot loader if
93 * comconsole is already the preferred console.
94 */
95 cons = getenv("console");
96 if ((cons != NULL && strcmp(cons, comconsole.c_name) == 0) ||
97 getenv("boot_multicons") != NULL) {
98 comc_curspeed = comc_getspeed();
99 }
100
101 env = getenv("comconsole_speed");
102 if (env != NULL) {
103 speed = comc_parseint(env);
104 if (speed > 0)
105 comc_curspeed = speed;
106 }
107
108 sprintf(intbuf, "%d", comc_curspeed);
109 unsetenv("comconsole_speed");
110 env_setenv("comconsole_speed", EV_VOLATILE, intbuf, comc_speed_set,
111 env_nounset);
112
113 env = getenv("comconsole_port");
114 if (env != NULL) {
115 port = comc_parseint(env);
116 if (port > 0)
117 comc_port = port;
118 }
119
120 sprintf(intbuf, "%d", comc_port);
121 unsetenv("comconsole_port");
122 env_setenv("comconsole_port", EV_VOLATILE, intbuf, comc_port_set,
123 env_nounset);
124
125 env = getenv("comconsole_pcidev");
126 if (env != NULL) {
127 locator = comc_parse_pcidev(env);
128 if (locator != 0)
129 comc_pcidev_handle(locator);
130 }
131
132 unsetenv("comconsole_pcidev");
133 env_setenv("comconsole_pcidev", EV_VOLATILE, env, comc_pcidev_set,
134 env_nounset);
135 }
|
| 136 comc_setup(comc_curspeed, comc_port);
|
140}
141
142static int
143comc_init(int arg)
144{
| 137}
138
139static int
140comc_init(int arg)
141{
|
145 if (comc_started && arg == 0)
146 return 0;
147 comc_started = 1;
| |
148
149 comc_setup(comc_curspeed, comc_port);
150
| 142
143 comc_setup(comc_curspeed, comc_port);
144
|
151 return(0);
| 145 if ((comconsole.c_flags & (C_PRESENTIN | C_PRESENTOUT)) ==
146 (C_PRESENTIN | C_PRESENTOUT))
147 return (CMD_OK);
148 return (CMD_ERROR);
|
152}
153
154static void
155comc_putchar(int c)
156{
157 int wait;
158
159 for (wait = COMC_TXWAIT; wait > 0; wait--)
160 if (inb(comc_port + com_lsr) & LSR_TXRDY) {
161 outb(comc_port + com_data, (u_char)c);
162 break;
163 }
164}
165
166static int
167comc_getchar(void)
168{
| 149}
150
151static void
152comc_putchar(int c)
153{
154 int wait;
155
156 for (wait = COMC_TXWAIT; wait > 0; wait--)
157 if (inb(comc_port + com_lsr) & LSR_TXRDY) {
158 outb(comc_port + com_data, (u_char)c);
159 break;
160 }
161}
162
163static int
164comc_getchar(void)
165{
|
169 return(comc_ischar() ? inb(comc_port + com_data) : -1);
| 166 return (comc_ischar() ? inb(comc_port + com_data) : -1);
|
170}
171
172static int
173comc_ischar(void)
174{
| 167}
168
169static int
170comc_ischar(void)
171{
|
175 return(inb(comc_port + com_lsr) & LSR_RXRDY);
| 172 return (inb(comc_port + com_lsr) & LSR_RXRDY);
|
176}
177
178static int
179comc_speed_set(struct env_var *ev, int flags, const void *value)
180{
181 int speed;
182
183 if (value == NULL || (speed = comc_parseint(value)) <= 0) {
184 printf("Invalid speed\n");
185 return (CMD_ERROR);
186 }
187
| 173}
174
175static int
176comc_speed_set(struct env_var *ev, int flags, const void *value)
177{
178 int speed;
179
180 if (value == NULL || (speed = comc_parseint(value)) <= 0) {
181 printf("Invalid speed\n");
182 return (CMD_ERROR);
183 }
184
|
188 if (comc_started && comc_curspeed != speed)
| 185 if ((comconsole.c_flags & (C_ACTIVEIN | C_ACTIVEOUT)) != 0 &&
186 comc_curspeed != speed)
|
189 comc_setup(speed, comc_port);
190
191 env_setenv(ev->ev_name, flags | EV_NOHOOK, value, NULL, NULL);
192
193 return (CMD_OK);
194}
195
196static int
197comc_port_set(struct env_var *ev, int flags, const void *value)
198{
199 int port;
200
201 if (value == NULL || (port = comc_parseint(value)) <= 0) {
202 printf("Invalid port\n");
203 return (CMD_ERROR);
204 }
205
| 187 comc_setup(speed, comc_port);
188
189 env_setenv(ev->ev_name, flags | EV_NOHOOK, value, NULL, NULL);
190
191 return (CMD_OK);
192}
193
194static int
195comc_port_set(struct env_var *ev, int flags, const void *value)
196{
197 int port;
198
199 if (value == NULL || (port = comc_parseint(value)) <= 0) {
200 printf("Invalid port\n");
201 return (CMD_ERROR);
202 }
203
|
206 if (comc_started && comc_port != port) {
| 204 if ((comconsole.c_flags & (C_ACTIVEIN | C_ACTIVEOUT)) != 0 &&
205 comc_port != port) {
|
207 comc_setup(comc_curspeed, port);
208 set_hw_console_hint();
209 }
210
211 env_setenv(ev->ev_name, flags | EV_NOHOOK, value, NULL, NULL);
212
213 return (CMD_OK);
214}
215
216static void
217set_hw_console_hint(void)
218{
219 char intbuf[64];
220
221 unsetenv("hw.uart.console");
222 sprintf(intbuf, "io:%d,br:%d", comc_port, comc_curspeed);
223 env_setenv("hw.uart.console", EV_VOLATILE, intbuf,
224 env_noset, env_nounset);
225}
226
227/*
228 * Input: bus:dev:func[:bar]. If bar is not specified, it is 0x10.
229 * Output: bar[24:16] bus[15:8] dev[7:3] func[2:0]
230 */
231static uint32_t
232comc_parse_pcidev(const char *string)
233{
234 char *p, *p1;
235 uint8_t bus, dev, func, bar;
236 uint32_t locator;
237 int pres;
238
239 pres = strtol(string, &p, 0);
240 if (p == string || *p != ':' || pres < 0 )
241 return (0);
242 bus = pres;
243 p1 = ++p;
244
245 pres = strtol(p1, &p, 0);
246 if (p == string || *p != ':' || pres < 0 )
247 return (0);
248 dev = pres;
249 p1 = ++p;
250
251 pres = strtol(p1, &p, 0);
252 if (p == string || (*p != ':' && *p != '\0') || pres < 0 )
253 return (0);
254 func = pres;
255
256 if (*p == ':') {
257 p1 = ++p;
258 pres = strtol(p1, &p, 0);
259 if (p == string || *p != '\0' || pres <= 0 )
260 return (0);
261 bar = pres;
262 } else
263 bar = 0x10;
264
265 locator = (bar << 16) | biospci_locator(bus, dev, func);
266 return (locator);
267}
268
269static int
270comc_pcidev_handle(uint32_t locator)
271{
272 char intbuf[64];
273 uint32_t port;
274
275 if (biospci_read_config(locator & 0xffff,
276 (locator & 0xff0000) >> 16, 2, &port) == -1) {
277 printf("Cannot read bar at 0x%x\n", locator);
278 return (CMD_ERROR);
279 }
280 if (!PCI_BAR_IO(port)) {
281 printf("Memory bar at 0x%x\n", locator);
282 return (CMD_ERROR);
283 }
284 port &= PCIM_BAR_IO_BASE;
285
286 sprintf(intbuf, "%d", port);
287 unsetenv("comconsole_port");
288 env_setenv("comconsole_port", EV_VOLATILE, intbuf,
289 comc_port_set, env_nounset);
290
291 comc_setup(comc_curspeed, port);
292 set_hw_console_hint();
293 comc_locator = locator;
294
295 return (CMD_OK);
296}
297
298static int
299comc_pcidev_set(struct env_var *ev, int flags, const void *value)
300{
301 uint32_t locator;
302 int error;
303
304 if (value == NULL || (locator = comc_parse_pcidev(value)) <= 0) {
305 printf("Invalid pcidev\n");
306 return (CMD_ERROR);
307 }
| 206 comc_setup(comc_curspeed, port);
207 set_hw_console_hint();
208 }
209
210 env_setenv(ev->ev_name, flags | EV_NOHOOK, value, NULL, NULL);
211
212 return (CMD_OK);
213}
214
215static void
216set_hw_console_hint(void)
217{
218 char intbuf[64];
219
220 unsetenv("hw.uart.console");
221 sprintf(intbuf, "io:%d,br:%d", comc_port, comc_curspeed);
222 env_setenv("hw.uart.console", EV_VOLATILE, intbuf,
223 env_noset, env_nounset);
224}
225
226/*
227 * Input: bus:dev:func[:bar]. If bar is not specified, it is 0x10.
228 * Output: bar[24:16] bus[15:8] dev[7:3] func[2:0]
229 */
230static uint32_t
231comc_parse_pcidev(const char *string)
232{
233 char *p, *p1;
234 uint8_t bus, dev, func, bar;
235 uint32_t locator;
236 int pres;
237
238 pres = strtol(string, &p, 0);
239 if (p == string || *p != ':' || pres < 0 )
240 return (0);
241 bus = pres;
242 p1 = ++p;
243
244 pres = strtol(p1, &p, 0);
245 if (p == string || *p != ':' || pres < 0 )
246 return (0);
247 dev = pres;
248 p1 = ++p;
249
250 pres = strtol(p1, &p, 0);
251 if (p == string || (*p != ':' && *p != '\0') || pres < 0 )
252 return (0);
253 func = pres;
254
255 if (*p == ':') {
256 p1 = ++p;
257 pres = strtol(p1, &p, 0);
258 if (p == string || *p != '\0' || pres <= 0 )
259 return (0);
260 bar = pres;
261 } else
262 bar = 0x10;
263
264 locator = (bar << 16) | biospci_locator(bus, dev, func);
265 return (locator);
266}
267
268static int
269comc_pcidev_handle(uint32_t locator)
270{
271 char intbuf[64];
272 uint32_t port;
273
274 if (biospci_read_config(locator & 0xffff,
275 (locator & 0xff0000) >> 16, 2, &port) == -1) {
276 printf("Cannot read bar at 0x%x\n", locator);
277 return (CMD_ERROR);
278 }
279 if (!PCI_BAR_IO(port)) {
280 printf("Memory bar at 0x%x\n", locator);
281 return (CMD_ERROR);
282 }
283 port &= PCIM_BAR_IO_BASE;
284
285 sprintf(intbuf, "%d", port);
286 unsetenv("comconsole_port");
287 env_setenv("comconsole_port", EV_VOLATILE, intbuf,
288 comc_port_set, env_nounset);
289
290 comc_setup(comc_curspeed, port);
291 set_hw_console_hint();
292 comc_locator = locator;
293
294 return (CMD_OK);
295}
296
297static int
298comc_pcidev_set(struct env_var *ev, int flags, const void *value)
299{
300 uint32_t locator;
301 int error;
302
303 if (value == NULL || (locator = comc_parse_pcidev(value)) <= 0) {
304 printf("Invalid pcidev\n");
305 return (CMD_ERROR);
306 }
|
308 if (comc_started && comc_locator != locator) {
| 307 if ((comconsole.c_flags & (C_ACTIVEIN | C_ACTIVEOUT)) != 0 &&
308 comc_locator != locator) {
|
309 error = comc_pcidev_handle(locator);
310 if (error != CMD_OK)
311 return (error);
312 }
313 env_setenv(ev->ev_name, flags | EV_NOHOOK, value, NULL, NULL);
314 return (CMD_OK);
315}
316
317static void
318comc_setup(int speed, int port)
319{
| 309 error = comc_pcidev_handle(locator);
310 if (error != CMD_OK)
311 return (error);
312 }
313 env_setenv(ev->ev_name, flags | EV_NOHOOK, value, NULL, NULL);
314 return (CMD_OK);
315}
316
317static void
318comc_setup(int speed, int port)
319{
|
| 320 static int TRY_COUNT = 1000000;
321 int tries;
|
320
321 comc_curspeed = speed;
322 comc_port = port;
323
324 outb(comc_port + com_cfcr, CFCR_DLAB | COMC_FMT);
325 outb(comc_port + com_dlbl, COMC_BPS(speed) & 0xff);
326 outb(comc_port + com_dlbh, COMC_BPS(speed) >> 8);
327 outb(comc_port + com_cfcr, COMC_FMT);
328 outb(comc_port + com_mcr, MCR_RTS | MCR_DTR);
329
| 322
323 comc_curspeed = speed;
324 comc_port = port;
325
326 outb(comc_port + com_cfcr, CFCR_DLAB | COMC_FMT);
327 outb(comc_port + com_dlbl, COMC_BPS(speed) & 0xff);
328 outb(comc_port + com_dlbh, COMC_BPS(speed) >> 8);
329 outb(comc_port + com_cfcr, COMC_FMT);
330 outb(comc_port + com_mcr, MCR_RTS | MCR_DTR);
331
|
| 332 tries = 0;
|
330 do
331 inb(comc_port + com_data);
| 333 do
334 inb(comc_port + com_data);
|
332 while (inb(comc_port + com_lsr) & LSR_RXRDY);
| 335 while (inb(comc_port + com_lsr) & LSR_RXRDY && ++tries < TRY_COUNT);
336
337 if (tries < TRY_COUNT)
338 comconsole.c_flags |= (C_PRESENTIN | C_PRESENTOUT);
339 else
340 comconsole.c_flags &= ~(C_PRESENTIN | C_PRESENTOUT);
|
333}
334
335static int
336comc_parseint(const char *speedstr)
337{
338 char *p;
339 int speed;
340
341 speed = strtol(speedstr, &p, 0);
342 if (p == speedstr || *p != '\0' || speed <= 0)
343 return (-1);
344
345 return (speed);
346}
347
348static int
349comc_getspeed(void)
350{
351 u_int divisor;
352 u_char dlbh;
353 u_char dlbl;
354 u_char cfcr;
355
356 cfcr = inb(comc_port + com_cfcr);
357 outb(comc_port + com_cfcr, CFCR_DLAB | cfcr);
358
359 dlbl = inb(comc_port + com_dlbl);
360 dlbh = inb(comc_port + com_dlbh);
361
362 outb(comc_port + com_cfcr, cfcr);
363
364 divisor = dlbh << 8 | dlbl;
365
366 /* XXX there should be more sanity checking. */
367 if (divisor == 0)
368 return (COMSPEED);
369 return (COMC_DIV2BPS(divisor));
370}
| 341}
342
343static int
344comc_parseint(const char *speedstr)
345{
346 char *p;
347 int speed;
348
349 speed = strtol(speedstr, &p, 0);
350 if (p == speedstr || *p != '\0' || speed <= 0)
351 return (-1);
352
353 return (speed);
354}
355
356static int
357comc_getspeed(void)
358{
359 u_int divisor;
360 u_char dlbh;
361 u_char dlbl;
362 u_char cfcr;
363
364 cfcr = inb(comc_port + com_cfcr);
365 outb(comc_port + com_cfcr, CFCR_DLAB | cfcr);
366
367 dlbl = inb(comc_port + com_dlbl);
368 dlbh = inb(comc_port + com_dlbh);
369
370 outb(comc_port + com_cfcr, cfcr);
371
372 divisor = dlbh << 8 | dlbl;
373
374 /* XXX there should be more sanity checking. */
375 if (divisor == 0)
376 return (COMSPEED);
377 return (COMC_DIV2BPS(divisor));
378}
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