2 * Copyright (c) 2008 Poul-Henning Kamp
3 * Copyright (c) 2010 Alexander Motin <mav@FreeBSD.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/systm.h>
38 #include <sys/clock.h>
40 #include <sys/mutex.h>
42 #include <sys/kernel.h>
43 #include <sys/module.h>
46 #include <sys/timeet.h>
50 #include <isa/isareg.h>
51 #include <isa/isavar.h>
53 #include <machine/intr_machdep.h>
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)
59 int atrtcclock_disable = 0;
61 static int rtc_reg = -1;
62 static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
63 static u_char rtc_statusb = RTCSB_24HR;
66 * RTC support routines
81 val = inb(IO_RTC + 1);
87 writertc(int reg, u_char val)
97 outb(IO_RTC + 1, val);
105 return(bcd2bin(rtcin(port)));
112 writertc(RTC_STATUSA, rtc_statusa);
113 writertc(RTC_STATUSB, RTCSB_24HR);
117 atrtc_rate(unsigned rate)
120 rtc_statusa = RTCSA_DIVIDER | rate;
121 writertc(RTC_STATUSA, rtc_statusa);
125 atrtc_enable_intr(void)
128 rtc_statusb |= RTCSB_PINTR;
129 writertc(RTC_STATUSB, rtc_statusb);
134 atrtc_disable_intr(void)
137 rtc_statusb &= ~RTCSB_PINTR;
138 writertc(RTC_STATUSB, rtc_statusb);
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);
155 atrtc_set(struct timespec *ts)
159 clock_ts_to_ct(ts, &ct);
161 /* Disable RTC updates and interrupts. */
162 writertc(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR);
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 */
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 */
176 /* Re-enable RTC updates and interrupts. */
177 writertc(RTC_STATUSB, rtc_statusb);
181 /**********************************************************************
182 * RTC driver for subr_rtc
186 int port_rid, intr_rid;
187 struct resource *port_res;
188 struct resource *intr_res;
190 struct eventtimer et;
194 rtc_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
197 atrtc_rate(max(fls(period + (period >> 1)) - 17, 1));
203 rtc_stop(struct eventtimer *et)
206 atrtc_disable_intr();
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.
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.
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.
234 struct atrtc_softc *sc = (struct atrtc_softc *)arg;
237 while (rtcin(RTC_INTR) & RTCIR_PERIOD) {
239 if (sc->et.et_active)
240 sc->et.et_event_cb(&sc->et, sc->et.et_arg);
242 return(flag ? FILTER_HANDLED : FILTER_STRAY);
246 * Attach to the ISA PnP descriptors for the timer and realtime clock.
248 static struct isa_pnp_id atrtc_ids[] = {
249 { 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
254 atrtc_probe(device_t dev)
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);
268 atrtc_attach(device_t dev)
270 struct atrtc_softc *sc;
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");
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)) {
286 while (bus_get_resource(dev, SYS_RES_IRQ, sc->intr_rid,
287 &s, NULL) == 0 && s != 8)
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");
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");
299 /* Bind IRQ to BSP to avoid live migration. */
300 bus_bind_intr(dev, sc->intr_res, 0);
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);
317 atrtc_resume(device_t dev)
325 atrtc_settime(device_t dev __unused, struct timespec *ts)
333 atrtc_gettime(device_t dev, struct timespec *ts)
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");
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.
350 while (rtcin(RTC_STATUSA) & RTCSA_TUP)
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;
364 ct.year += (ct.year < 80 ? 2000 : 1900);
367 /* Set dow = -1 because some clocks don't set it correctly. */
369 return (clock_ct_to_ts(&ct, ts));
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),
382 /* clock interface */
383 DEVMETHOD(clock_gettime, atrtc_gettime),
384 DEVMETHOD(clock_settime, atrtc_settime),
389 static driver_t atrtc_driver = {
392 sizeof(struct atrtc_softc),
395 static devclass_t atrtc_devclass;
397 DRIVER_MODULE(atrtc, isa, atrtc_driver, atrtc_devclass, 0, 0);
398 DRIVER_MODULE(atrtc, acpi, atrtc_driver, atrtc_devclass, 0, 0);
404 DB_SHOW_COMMAND(rtc, rtc)
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));