FreeBSD/Linux Kernel Cross Reference
sys/x86/isa/atrtc.c
1 /*-
2 * Copyright (c) 2008 Poul-Henning Kamp
3 * Copyright (c) 2010 Alexander Motin <mav@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: releng/11.1/sys/x86/isa/atrtc.c 298928 2016-05-02 16:14:55Z royger $
28 */
29
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD: releng/11.1/sys/x86/isa/atrtc.c 298928 2016-05-02 16:14:55Z royger $");
32
33 #include "opt_isa.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/bus.h>
38 #include <sys/clock.h>
39 #include <sys/lock.h>
40 #include <sys/mutex.h>
41 #include <sys/kdb.h>
42 #include <sys/kernel.h>
43 #include <sys/module.h>
44 #include <sys/proc.h>
45 #include <sys/rman.h>
46 #include <sys/timeet.h>
47
48 #include <isa/rtc.h>
49 #ifdef DEV_ISA
50 #include <isa/isareg.h>
51 #include <isa/isavar.h>
52 #endif
53 #include <machine/intr_machdep.h>
54 #include "clock_if.h"
55
56 #define RTC_LOCK do { if (!kdb_active) mtx_lock_spin(&clock_lock); } while (0)
57 #define RTC_UNLOCK do { if (!kdb_active) mtx_unlock_spin(&clock_lock); } while (0)
58
59 int atrtcclock_disable = 0;
60
61 static int rtc_reg = -1;
62 static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
63 static u_char rtc_statusb = RTCSB_24HR;
64
65 /*
66 * RTC support routines
67 */
68
69 int
70 rtcin(int reg)
71 {
72 u_char val;
73
74 RTC_LOCK;
75 if (rtc_reg != reg) {
76 inb(0x84);
77 outb(IO_RTC, reg);
78 rtc_reg = reg;
79 inb(0x84);
80 }
81 val = inb(IO_RTC + 1);
82 RTC_UNLOCK;
83 return (val);
84 }
85
86 void
87 writertc(int reg, u_char val)
88 {
89
90 RTC_LOCK;
91 if (rtc_reg != reg) {
92 inb(0x84);
93 outb(IO_RTC, reg);
94 rtc_reg = reg;
95 inb(0x84);
96 }
97 outb(IO_RTC + 1, val);
98 inb(0x84);
99 RTC_UNLOCK;
100 }
101
102 static __inline int
103 readrtc(int port)
104 {
105 return(bcd2bin(rtcin(port)));
106 }
107
108 static void
109 atrtc_start(void)
110 {
111
112 writertc(RTC_STATUSA, rtc_statusa);
113 writertc(RTC_STATUSB, RTCSB_24HR);
114 }
115
116 static void
117 atrtc_rate(unsigned rate)
118 {
119
120 rtc_statusa = RTCSA_DIVIDER | rate;
121 writertc(RTC_STATUSA, rtc_statusa);
122 }
123
124 static void
125 atrtc_enable_intr(void)
126 {
127
128 rtc_statusb |= RTCSB_PINTR;
129 writertc(RTC_STATUSB, rtc_statusb);
130 rtcin(RTC_INTR);
131 }
132
133 static void
134 atrtc_disable_intr(void)
135 {
136
137 rtc_statusb &= ~RTCSB_PINTR;
138 writertc(RTC_STATUSB, rtc_statusb);
139 rtcin(RTC_INTR);
140 }
141
142 void
143 atrtc_restore(void)
144 {
145
146 /* Restore all of the RTC's "status" (actually, control) registers. */
147 rtcin(RTC_STATUSA); /* dummy to get rtc_reg set */
148 writertc(RTC_STATUSB, RTCSB_24HR);
149 writertc(RTC_STATUSA, rtc_statusa);
150 writertc(RTC_STATUSB, rtc_statusb);
151 rtcin(RTC_INTR);
152 }
153
154 void
155 atrtc_set(struct timespec *ts)
156 {
157 struct clocktime ct;
158
159 clock_ts_to_ct(ts, &ct);
160
161 /* Disable RTC updates and interrupts. */
162 writertc(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR);
163
164 writertc(RTC_SEC, bin2bcd(ct.sec)); /* Write back Seconds */
165 writertc(RTC_MIN, bin2bcd(ct.min)); /* Write back Minutes */
166 writertc(RTC_HRS, bin2bcd(ct.hour)); /* Write back Hours */
167
168 writertc(RTC_WDAY, ct.dow + 1); /* Write back Weekday */
169 writertc(RTC_DAY, bin2bcd(ct.day)); /* Write back Day */
170 writertc(RTC_MONTH, bin2bcd(ct.mon)); /* Write back Month */
171 writertc(RTC_YEAR, bin2bcd(ct.year % 100)); /* Write back Year */
172 #ifdef USE_RTC_CENTURY
173 writertc(RTC_CENTURY, bin2bcd(ct.year / 100)); /* ... and Century */
174 #endif
175
176 /* Re-enable RTC updates and interrupts. */
177 writertc(RTC_STATUSB, rtc_statusb);
178 rtcin(RTC_INTR);
179 }
180
181 /**********************************************************************
182 * RTC driver for subr_rtc
183 */
184
185 struct atrtc_softc {
186 int port_rid, intr_rid;
187 struct resource *port_res;
188 struct resource *intr_res;
189 void *intr_handler;
190 struct eventtimer et;
191 };
192
193 static int
194 rtc_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
195 {
196
197 atrtc_rate(max(fls(period + (period >> 1)) - 17, 1));
198 atrtc_enable_intr();
199 return (0);
200 }
201
202 static int
203 rtc_stop(struct eventtimer *et)
204 {
205
206 atrtc_disable_intr();
207 return (0);
208 }
209
210 /*
211 * This routine receives statistical clock interrupts from the RTC.
212 * As explained above, these occur at 128 interrupts per second.
213 * When profiling, we receive interrupts at a rate of 1024 Hz.
214 *
215 * This does not actually add as much overhead as it sounds, because
216 * when the statistical clock is active, the hardclock driver no longer
217 * needs to keep (inaccurate) statistics on its own. This decouples
218 * statistics gathering from scheduling interrupts.
219 *
220 * The RTC chip requires that we read status register C (RTC_INTR)
221 * to acknowledge an interrupt, before it will generate the next one.
222 * Under high interrupt load, rtcintr() can be indefinitely delayed and
223 * the clock can tick immediately after the read from RTC_INTR. In this
224 * case, the mc146818A interrupt signal will not drop for long enough
225 * to register with the 8259 PIC. If an interrupt is missed, the stat
226 * clock will halt, considerably degrading system performance. This is
227 * why we use 'while' rather than a more straightforward 'if' below.
228 * Stat clock ticks can still be lost, causing minor loss of accuracy
229 * in the statistics, but the stat clock will no longer stop.
230 */
231 static int
232 rtc_intr(void *arg)
233 {
234 struct atrtc_softc *sc = (struct atrtc_softc *)arg;
235 int flag = 0;
236
237 while (rtcin(RTC_INTR) & RTCIR_PERIOD) {
238 flag = 1;
239 if (sc->et.et_active)
240 sc->et.et_event_cb(&sc->et, sc->et.et_arg);
241 }
242 return(flag ? FILTER_HANDLED : FILTER_STRAY);
243 }
244
245 /*
246 * Attach to the ISA PnP descriptors for the timer and realtime clock.
247 */
248 static struct isa_pnp_id atrtc_ids[] = {
249 { 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
250 { 0 }
251 };
252
253 static int
254 atrtc_probe(device_t dev)
255 {
256 int result;
257
258 result = ISA_PNP_PROBE(device_get_parent(dev), dev, atrtc_ids);
259 /* ENOENT means no PnP-ID, device is hinted. */
260 if (result == ENOENT) {
261 device_set_desc(dev, "AT realtime clock");
262 return (BUS_PROBE_LOW_PRIORITY);
263 }
264 return (result);
265 }
266
267 static int
268 atrtc_attach(device_t dev)
269 {
270 struct atrtc_softc *sc;
271 rman_res_t s;
272 int i;
273
274 sc = device_get_softc(dev);
275 sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT, &sc->port_rid,
276 IO_RTC, IO_RTC + 1, 2, RF_ACTIVE);
277 if (sc->port_res == NULL)
278 device_printf(dev, "Warning: Couldn't map I/O.\n");
279 atrtc_start();
280 clock_register(dev, 1000000);
281 bzero(&sc->et, sizeof(struct eventtimer));
282 if (!atrtcclock_disable &&
283 (resource_int_value(device_get_name(dev), device_get_unit(dev),
284 "clock", &i) != 0 || i != 0)) {
285 sc->intr_rid = 0;
286 while (bus_get_resource(dev, SYS_RES_IRQ, sc->intr_rid,
287 &s, NULL) == 0 && s != 8)
288 sc->intr_rid++;
289 sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
290 &sc->intr_rid, 8, 8, 1, RF_ACTIVE);
291 if (sc->intr_res == NULL) {
292 device_printf(dev, "Can't map interrupt.\n");
293 return (0);
294 } else if ((bus_setup_intr(dev, sc->intr_res, INTR_TYPE_CLK,
295 rtc_intr, NULL, sc, &sc->intr_handler))) {
296 device_printf(dev, "Can't setup interrupt.\n");
297 return (0);
298 } else {
299 /* Bind IRQ to BSP to avoid live migration. */
300 bus_bind_intr(dev, sc->intr_res, 0);
301 }
302 sc->et.et_name = "RTC";
303 sc->et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_POW2DIV;
304 sc->et.et_quality = 0;
305 sc->et.et_frequency = 32768;
306 sc->et.et_min_period = 0x00080000;
307 sc->et.et_max_period = 0x80000000;
308 sc->et.et_start = rtc_start;
309 sc->et.et_stop = rtc_stop;
310 sc->et.et_priv = dev;
311 et_register(&sc->et);
312 }
313 return(0);
314 }
315
316 static int
317 atrtc_resume(device_t dev)
318 {
319
320 atrtc_restore();
321 return(0);
322 }
323
324 static int
325 atrtc_settime(device_t dev __unused, struct timespec *ts)
326 {
327
328 atrtc_set(ts);
329 return (0);
330 }
331
332 static int
333 atrtc_gettime(device_t dev, struct timespec *ts)
334 {
335 struct clocktime ct;
336
337 /* Look if we have a RTC present and the time is valid */
338 if (!(rtcin(RTC_STATUSD) & RTCSD_PWR)) {
339 device_printf(dev, "WARNING: Battery failure indication\n");
340 return (EINVAL);
341 }
342
343 /*
344 * wait for time update to complete
345 * If RTCSA_TUP is zero, we have at least 244us before next update.
346 * This is fast enough on most hardware, but a refinement would be
347 * to make sure that no more than 240us pass after we start reading,
348 * and try again if so.
349 */
350 while (rtcin(RTC_STATUSA) & RTCSA_TUP)
351 continue;
352 critical_enter();
353 ct.nsec = 0;
354 ct.sec = readrtc(RTC_SEC);
355 ct.min = readrtc(RTC_MIN);
356 ct.hour = readrtc(RTC_HRS);
357 ct.day = readrtc(RTC_DAY);
358 ct.dow = readrtc(RTC_WDAY) - 1;
359 ct.mon = readrtc(RTC_MONTH);
360 ct.year = readrtc(RTC_YEAR);
361 #ifdef USE_RTC_CENTURY
362 ct.year += readrtc(RTC_CENTURY) * 100;
363 #else
364 ct.year += (ct.year < 80 ? 2000 : 1900);
365 #endif
366 critical_exit();
367 /* Set dow = -1 because some clocks don't set it correctly. */
368 ct.dow = -1;
369 return (clock_ct_to_ts(&ct, ts));
370 }
371
372 static device_method_t atrtc_methods[] = {
373 /* Device interface */
374 DEVMETHOD(device_probe, atrtc_probe),
375 DEVMETHOD(device_attach, atrtc_attach),
376 DEVMETHOD(device_detach, bus_generic_detach),
377 DEVMETHOD(device_shutdown, bus_generic_shutdown),
378 DEVMETHOD(device_suspend, bus_generic_suspend),
379 /* XXX stop statclock? */
380 DEVMETHOD(device_resume, atrtc_resume),
381
382 /* clock interface */
383 DEVMETHOD(clock_gettime, atrtc_gettime),
384 DEVMETHOD(clock_settime, atrtc_settime),
385
386 { 0, 0 }
387 };
388
389 static driver_t atrtc_driver = {
390 "atrtc",
391 atrtc_methods,
392 sizeof(struct atrtc_softc),
393 };
394
395 static devclass_t atrtc_devclass;
396
397 DRIVER_MODULE(atrtc, isa, atrtc_driver, atrtc_devclass, 0, 0);
398 DRIVER_MODULE(atrtc, acpi, atrtc_driver, atrtc_devclass, 0, 0);
399
400 #include "opt_ddb.h"
401 #ifdef DDB
402 #include <ddb/ddb.h>
403
404 DB_SHOW_COMMAND(rtc, rtc)
405 {
406 printf("%02x/%02x/%02x %02x:%02x:%02x, A = %02x, B = %02x, C = %02x\n",
407 rtcin(RTC_YEAR), rtcin(RTC_MONTH), rtcin(RTC_DAY),
408 rtcin(RTC_HRS), rtcin(RTC_MIN), rtcin(RTC_SEC),
409 rtcin(RTC_STATUSA), rtcin(RTC_STATUSB), rtcin(RTC_INTR));
410 }
411 #endif /* DDB */
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