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/9.1/sys/x86/isa/atrtc.c 216490 2010-12-16 17:05:28Z jhb $
28 */
29
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD: releng/9.1/sys/x86/isa/atrtc.c 216490 2010-12-16 17:05:28Z jhb $");
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/kernel.h>
42 #include <sys/module.h>
43 #include <sys/proc.h>
44 #include <sys/rman.h>
45 #include <sys/timeet.h>
46
47 #include <isa/rtc.h>
48 #ifdef DEV_ISA
49 #include <isa/isareg.h>
50 #include <isa/isavar.h>
51 #endif
52 #include <machine/intr_machdep.h>
53 #include "clock_if.h"
54
55 #define RTC_LOCK mtx_lock_spin(&clock_lock)
56 #define RTC_UNLOCK mtx_unlock_spin(&clock_lock)
57
58 int atrtcclock_disable = 0;
59
60 static int rtc_reg = -1;
61 static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
62 static u_char rtc_statusb = RTCSB_24HR;
63
64 /*
65 * RTC support routines
66 */
67
68 int
69 rtcin(int reg)
70 {
71 u_char val;
72
73 RTC_LOCK;
74 if (rtc_reg != reg) {
75 inb(0x84);
76 outb(IO_RTC, reg);
77 rtc_reg = reg;
78 inb(0x84);
79 }
80 val = inb(IO_RTC + 1);
81 RTC_UNLOCK;
82 return (val);
83 }
84
85 void
86 writertc(int reg, u_char val)
87 {
88
89 RTC_LOCK;
90 if (rtc_reg != reg) {
91 inb(0x84);
92 outb(IO_RTC, reg);
93 rtc_reg = reg;
94 inb(0x84);
95 }
96 outb(IO_RTC + 1, val);
97 inb(0x84);
98 RTC_UNLOCK;
99 }
100
101 static __inline int
102 readrtc(int port)
103 {
104 return(bcd2bin(rtcin(port)));
105 }
106
107 static void
108 atrtc_start(void)
109 {
110
111 writertc(RTC_STATUSA, rtc_statusa);
112 writertc(RTC_STATUSB, RTCSB_24HR);
113 }
114
115 static void
116 atrtc_rate(unsigned rate)
117 {
118
119 rtc_statusa = RTCSA_DIVIDER | rate;
120 writertc(RTC_STATUSA, rtc_statusa);
121 }
122
123 static void
124 atrtc_enable_intr(void)
125 {
126
127 rtc_statusb |= RTCSB_PINTR;
128 writertc(RTC_STATUSB, rtc_statusb);
129 rtcin(RTC_INTR);
130 }
131
132 static void
133 atrtc_disable_intr(void)
134 {
135
136 rtc_statusb &= ~RTCSB_PINTR;
137 writertc(RTC_STATUSB, rtc_statusb);
138 rtcin(RTC_INTR);
139 }
140
141 void
142 atrtc_restore(void)
143 {
144
145 /* Restore all of the RTC's "status" (actually, control) registers. */
146 rtcin(RTC_STATUSA); /* dummy to get rtc_reg set */
147 writertc(RTC_STATUSB, RTCSB_24HR);
148 writertc(RTC_STATUSA, rtc_statusa);
149 writertc(RTC_STATUSB, rtc_statusb);
150 rtcin(RTC_INTR);
151 }
152
153 /**********************************************************************
154 * RTC driver for subr_rtc
155 */
156
157 struct atrtc_softc {
158 int port_rid, intr_rid;
159 struct resource *port_res;
160 struct resource *intr_res;
161 void *intr_handler;
162 struct eventtimer et;
163 };
164
165 static int
166 rtc_start(struct eventtimer *et,
167 struct bintime *first, struct bintime *period)
168 {
169
170 atrtc_rate(max(fls((period->frac + (period->frac >> 1)) >> 32) - 17, 1));
171 atrtc_enable_intr();
172 return (0);
173 }
174
175 static int
176 rtc_stop(struct eventtimer *et)
177 {
178
179 atrtc_disable_intr();
180 return (0);
181 }
182
183 /*
184 * This routine receives statistical clock interrupts from the RTC.
185 * As explained above, these occur at 128 interrupts per second.
186 * When profiling, we receive interrupts at a rate of 1024 Hz.
187 *
188 * This does not actually add as much overhead as it sounds, because
189 * when the statistical clock is active, the hardclock driver no longer
190 * needs to keep (inaccurate) statistics on its own. This decouples
191 * statistics gathering from scheduling interrupts.
192 *
193 * The RTC chip requires that we read status register C (RTC_INTR)
194 * to acknowledge an interrupt, before it will generate the next one.
195 * Under high interrupt load, rtcintr() can be indefinitely delayed and
196 * the clock can tick immediately after the read from RTC_INTR. In this
197 * case, the mc146818A interrupt signal will not drop for long enough
198 * to register with the 8259 PIC. If an interrupt is missed, the stat
199 * clock will halt, considerably degrading system performance. This is
200 * why we use 'while' rather than a more straightforward 'if' below.
201 * Stat clock ticks can still be lost, causing minor loss of accuracy
202 * in the statistics, but the stat clock will no longer stop.
203 */
204 static int
205 rtc_intr(void *arg)
206 {
207 struct atrtc_softc *sc = (struct atrtc_softc *)arg;
208 int flag = 0;
209
210 while (rtcin(RTC_INTR) & RTCIR_PERIOD) {
211 flag = 1;
212 if (sc->et.et_active)
213 sc->et.et_event_cb(&sc->et, sc->et.et_arg);
214 }
215 return(flag ? FILTER_HANDLED : FILTER_STRAY);
216 }
217
218 /*
219 * Attach to the ISA PnP descriptors for the timer and realtime clock.
220 */
221 static struct isa_pnp_id atrtc_ids[] = {
222 { 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
223 { 0 }
224 };
225
226 static int
227 atrtc_probe(device_t dev)
228 {
229 int result;
230
231 result = ISA_PNP_PROBE(device_get_parent(dev), dev, atrtc_ids);
232 /* ENOENT means no PnP-ID, device is hinted. */
233 if (result == ENOENT) {
234 device_set_desc(dev, "AT realtime clock");
235 return (BUS_PROBE_LOW_PRIORITY);
236 }
237 return (result);
238 }
239
240 static int
241 atrtc_attach(device_t dev)
242 {
243 struct atrtc_softc *sc;
244 u_long s;
245 int i;
246
247 sc = device_get_softc(dev);
248 sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT, &sc->port_rid,
249 IO_RTC, IO_RTC + 1, 2, RF_ACTIVE);
250 if (sc->port_res == NULL)
251 device_printf(dev, "Warning: Couldn't map I/O.\n");
252 atrtc_start();
253 clock_register(dev, 1000000);
254 bzero(&sc->et, sizeof(struct eventtimer));
255 if (!atrtcclock_disable &&
256 (resource_int_value(device_get_name(dev), device_get_unit(dev),
257 "clock", &i) != 0 || i != 0)) {
258 sc->intr_rid = 0;
259 while (bus_get_resource(dev, SYS_RES_IRQ, sc->intr_rid,
260 &s, NULL) == 0 && s != 8)
261 sc->intr_rid++;
262 sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
263 &sc->intr_rid, 8, 8, 1, RF_ACTIVE);
264 if (sc->intr_res == NULL) {
265 device_printf(dev, "Can't map interrupt.\n");
266 return (0);
267 } else if ((bus_setup_intr(dev, sc->intr_res, INTR_TYPE_CLK,
268 rtc_intr, NULL, sc, &sc->intr_handler))) {
269 device_printf(dev, "Can't setup interrupt.\n");
270 return (0);
271 } else {
272 /* Bind IRQ to BSP to avoid live migration. */
273 bus_bind_intr(dev, sc->intr_res, 0);
274 }
275 sc->et.et_name = "RTC";
276 sc->et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_POW2DIV;
277 sc->et.et_quality = 0;
278 sc->et.et_frequency = 32768;
279 sc->et.et_min_period.sec = 0;
280 sc->et.et_min_period.frac = 0x0008LLU << 48;
281 sc->et.et_max_period.sec = 0;
282 sc->et.et_max_period.frac = 0x8000LLU << 48;
283 sc->et.et_start = rtc_start;
284 sc->et.et_stop = rtc_stop;
285 sc->et.et_priv = dev;
286 et_register(&sc->et);
287 }
288 return(0);
289 }
290
291 static int
292 atrtc_resume(device_t dev)
293 {
294
295 atrtc_restore();
296 return(0);
297 }
298
299 static int
300 atrtc_settime(device_t dev __unused, struct timespec *ts)
301 {
302 struct clocktime ct;
303
304 clock_ts_to_ct(ts, &ct);
305
306 /* Disable RTC updates and interrupts. */
307 writertc(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR);
308
309 writertc(RTC_SEC, bin2bcd(ct.sec)); /* Write back Seconds */
310 writertc(RTC_MIN, bin2bcd(ct.min)); /* Write back Minutes */
311 writertc(RTC_HRS, bin2bcd(ct.hour)); /* Write back Hours */
312
313 writertc(RTC_WDAY, ct.dow + 1); /* Write back Weekday */
314 writertc(RTC_DAY, bin2bcd(ct.day)); /* Write back Day */
315 writertc(RTC_MONTH, bin2bcd(ct.mon)); /* Write back Month */
316 writertc(RTC_YEAR, bin2bcd(ct.year % 100)); /* Write back Year */
317 #ifdef USE_RTC_CENTURY
318 writertc(RTC_CENTURY, bin2bcd(ct.year / 100)); /* ... and Century */
319 #endif
320
321 /* Reenable RTC updates and interrupts. */
322 writertc(RTC_STATUSB, rtc_statusb);
323 rtcin(RTC_INTR);
324 return (0);
325 }
326
327 static int
328 atrtc_gettime(device_t dev, struct timespec *ts)
329 {
330 struct clocktime ct;
331 int s;
332
333 /* Look if we have a RTC present and the time is valid */
334 if (!(rtcin(RTC_STATUSD) & RTCSD_PWR)) {
335 device_printf(dev, "WARNING: Battery failure indication\n");
336 return (EINVAL);
337 }
338
339 /* wait for time update to complete */
340 /* If RTCSA_TUP is zero, we have at least 244us before next update */
341 s = splhigh();
342 while (rtcin(RTC_STATUSA) & RTCSA_TUP) {
343 splx(s);
344 s = splhigh();
345 }
346 ct.nsec = 0;
347 ct.sec = readrtc(RTC_SEC);
348 ct.min = readrtc(RTC_MIN);
349 ct.hour = readrtc(RTC_HRS);
350 ct.day = readrtc(RTC_DAY);
351 ct.dow = readrtc(RTC_WDAY) - 1;
352 ct.mon = readrtc(RTC_MONTH);
353 ct.year = readrtc(RTC_YEAR);
354 #ifdef USE_RTC_CENTURY
355 ct.year += readrtc(RTC_CENTURY) * 100;
356 #else
357 ct.year += 2000;
358 #endif
359 /* Set dow = -1 because some clocks don't set it correctly. */
360 ct.dow = -1;
361 return (clock_ct_to_ts(&ct, ts));
362 }
363
364 static device_method_t atrtc_methods[] = {
365 /* Device interface */
366 DEVMETHOD(device_probe, atrtc_probe),
367 DEVMETHOD(device_attach, atrtc_attach),
368 DEVMETHOD(device_detach, bus_generic_detach),
369 DEVMETHOD(device_shutdown, bus_generic_shutdown),
370 DEVMETHOD(device_suspend, bus_generic_suspend),
371 /* XXX stop statclock? */
372 DEVMETHOD(device_resume, atrtc_resume),
373
374 /* clock interface */
375 DEVMETHOD(clock_gettime, atrtc_gettime),
376 DEVMETHOD(clock_settime, atrtc_settime),
377
378 { 0, 0 }
379 };
380
381 static driver_t atrtc_driver = {
382 "atrtc",
383 atrtc_methods,
384 sizeof(struct atrtc_softc),
385 };
386
387 static devclass_t atrtc_devclass;
388
389 DRIVER_MODULE(atrtc, isa, atrtc_driver, atrtc_devclass, 0, 0);
390 DRIVER_MODULE(atrtc, acpi, atrtc_driver, atrtc_devclass, 0, 0);
391
392 #include "opt_ddb.h"
393 #ifdef DDB
394 #include <ddb/ddb.h>
395
396 DB_SHOW_COMMAND(rtc, rtc)
397 {
398 printf("%02x/%02x/%02x %02x:%02x:%02x, A = %02x, B = %02x, C = %02x\n",
399 rtcin(RTC_YEAR), rtcin(RTC_MONTH), rtcin(RTC_DAY),
400 rtcin(RTC_HRS), rtcin(RTC_MIN), rtcin(RTC_SEC),
401 rtcin(RTC_STATUSA), rtcin(RTC_STATUSB), rtcin(RTC_INTR));
402 }
403 #endif /* DDB */
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