2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2008 Poul-Henning Kamp
5 * Copyright (c) 2010 Alexander Motin <mav@FreeBSD.org>
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
37 #include <sys/param.h>
38 #include <sys/systm.h>
40 #include <sys/clock.h>
42 #include <sys/mutex.h>
44 #include <sys/kernel.h>
45 #include <sys/module.h>
48 #include <sys/timeet.h>
52 #include <isa/isareg.h>
53 #include <isa/isavar.h>
55 #include <machine/intr_machdep.h>
59 * atrtc_lock protects low-level access to individual hardware registers.
60 * atrtc_time_lock protects the entire sequence of accessing multiple registers
61 * to read or write the date and time.
63 static struct mtx atrtc_lock;
64 MTX_SYSINIT(atrtc_lock_init, &atrtc_lock, "atrtc", MTX_SPIN);
66 struct mtx atrtc_time_lock;
67 MTX_SYSINIT(atrtc_time_lock_init, &atrtc_time_lock, "atrtc", MTX_DEF);
69 int atrtcclock_disable = 0;
71 static int rtc_reg = -1;
72 static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
73 static u_char rtc_statusb = RTCSB_24HR;
76 * RTC support routines
89 return (inb(IO_RTC + 1));
93 rtcout_locked(int reg, u_char val)
102 outb(IO_RTC + 1, val);
111 mtx_lock_spin(&atrtc_lock);
112 val = rtcin_locked(reg);
113 mtx_unlock_spin(&atrtc_lock);
118 writertc(int reg, u_char val)
121 mtx_lock_spin(&atrtc_lock);
122 rtcout_locked(reg, val);
123 mtx_unlock_spin(&atrtc_lock);
130 mtx_lock_spin(&atrtc_lock);
131 rtcout_locked(RTC_STATUSA, rtc_statusa);
132 rtcout_locked(RTC_STATUSB, RTCSB_24HR);
133 mtx_unlock_spin(&atrtc_lock);
137 atrtc_rate(unsigned rate)
140 rtc_statusa = RTCSA_DIVIDER | rate;
141 writertc(RTC_STATUSA, rtc_statusa);
145 atrtc_enable_intr(void)
148 rtc_statusb |= RTCSB_PINTR;
149 mtx_lock_spin(&atrtc_lock);
150 rtcout_locked(RTC_STATUSB, rtc_statusb);
151 rtcin_locked(RTC_INTR);
152 mtx_unlock_spin(&atrtc_lock);
156 atrtc_disable_intr(void)
159 rtc_statusb &= ~RTCSB_PINTR;
160 mtx_lock_spin(&atrtc_lock);
161 rtcout_locked(RTC_STATUSB, rtc_statusb);
162 rtcin_locked(RTC_INTR);
163 mtx_unlock_spin(&atrtc_lock);
170 /* Restore all of the RTC's "status" (actually, control) registers. */
171 mtx_lock_spin(&atrtc_lock);
172 rtcin_locked(RTC_STATUSA); /* dummy to get rtc_reg set */
173 rtcout_locked(RTC_STATUSB, RTCSB_24HR);
174 rtcout_locked(RTC_STATUSA, rtc_statusa);
175 rtcout_locked(RTC_STATUSB, rtc_statusb);
176 rtcin_locked(RTC_INTR);
177 mtx_unlock_spin(&atrtc_lock);
180 /**********************************************************************
181 * RTC driver for subr_rtc
185 int port_rid, intr_rid;
186 struct resource *port_res;
187 struct resource *intr_res;
189 struct eventtimer et;
193 rtc_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
196 atrtc_rate(max(fls(period + (period >> 1)) - 17, 1));
202 rtc_stop(struct eventtimer *et)
205 atrtc_disable_intr();
210 * This routine receives statistical clock interrupts from the RTC.
211 * As explained above, these occur at 128 interrupts per second.
212 * When profiling, we receive interrupts at a rate of 1024 Hz.
214 * This does not actually add as much overhead as it sounds, because
215 * when the statistical clock is active, the hardclock driver no longer
216 * needs to keep (inaccurate) statistics on its own. This decouples
217 * statistics gathering from scheduling interrupts.
219 * The RTC chip requires that we read status register C (RTC_INTR)
220 * to acknowledge an interrupt, before it will generate the next one.
221 * Under high interrupt load, rtcintr() can be indefinitely delayed and
222 * the clock can tick immediately after the read from RTC_INTR. In this
223 * case, the mc146818A interrupt signal will not drop for long enough
224 * to register with the 8259 PIC. If an interrupt is missed, the stat
225 * clock will halt, considerably degrading system performance. This is
226 * why we use 'while' rather than a more straightforward 'if' below.
227 * Stat clock ticks can still be lost, causing minor loss of accuracy
228 * in the statistics, but the stat clock will no longer stop.
233 struct atrtc_softc *sc = (struct atrtc_softc *)arg;
236 while (rtcin(RTC_INTR) & RTCIR_PERIOD) {
238 if (sc->et.et_active)
239 sc->et.et_event_cb(&sc->et, sc->et.et_arg);
241 return(flag ? FILTER_HANDLED : FILTER_STRAY);
245 * Attach to the ISA PnP descriptors for the timer and realtime clock.
247 static struct isa_pnp_id atrtc_ids[] = {
248 { 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
253 atrtc_probe(device_t dev)
257 result = ISA_PNP_PROBE(device_get_parent(dev), dev, atrtc_ids);
258 /* ENOENT means no PnP-ID, device is hinted. */
259 if (result == ENOENT) {
260 device_set_desc(dev, "AT realtime clock");
261 return (BUS_PROBE_LOW_PRIORITY);
267 atrtc_attach(device_t dev)
269 struct atrtc_softc *sc;
273 sc = device_get_softc(dev);
274 sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT, &sc->port_rid,
275 IO_RTC, IO_RTC + 1, 2, RF_ACTIVE);
276 if (sc->port_res == NULL)
277 device_printf(dev, "Warning: Couldn't map I/O.\n");
279 clock_register(dev, 1000000);
280 bzero(&sc->et, sizeof(struct eventtimer));
281 if (!atrtcclock_disable &&
282 (resource_int_value(device_get_name(dev), device_get_unit(dev),
283 "clock", &i) != 0 || i != 0)) {
285 while (bus_get_resource(dev, SYS_RES_IRQ, sc->intr_rid,
286 &s, NULL) == 0 && s != 8)
288 sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
289 &sc->intr_rid, 8, 8, 1, RF_ACTIVE);
290 if (sc->intr_res == NULL) {
291 device_printf(dev, "Can't map interrupt.\n");
293 } else if ((bus_setup_intr(dev, sc->intr_res, INTR_TYPE_CLK,
294 rtc_intr, NULL, sc, &sc->intr_handler))) {
295 device_printf(dev, "Can't setup interrupt.\n");
298 /* Bind IRQ to BSP to avoid live migration. */
299 bus_bind_intr(dev, sc->intr_res, 0);
301 sc->et.et_name = "RTC";
302 sc->et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_POW2DIV;
303 sc->et.et_quality = 0;
304 sc->et.et_frequency = 32768;
305 sc->et.et_min_period = 0x00080000;
306 sc->et.et_max_period = 0x80000000;
307 sc->et.et_start = rtc_start;
308 sc->et.et_stop = rtc_stop;
309 sc->et.et_priv = dev;
310 et_register(&sc->et);
316 atrtc_resume(device_t dev)
324 atrtc_settime(device_t dev __unused, struct timespec *ts)
326 struct bcd_clocktime bct;
328 clock_ts_to_bcd(ts, &bct, false);
329 clock_dbgprint_bcd(dev, CLOCK_DBG_WRITE, &bct);
331 mtx_lock(&atrtc_time_lock);
332 mtx_lock_spin(&atrtc_lock);
334 /* Disable RTC updates and interrupts. */
335 rtcout_locked(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR);
337 /* Write all the time registers. */
338 rtcout_locked(RTC_SEC, bct.sec);
339 rtcout_locked(RTC_MIN, bct.min);
340 rtcout_locked(RTC_HRS, bct.hour);
341 rtcout_locked(RTC_WDAY, bct.dow + 1);
342 rtcout_locked(RTC_DAY, bct.day);
343 rtcout_locked(RTC_MONTH, bct.mon);
344 rtcout_locked(RTC_YEAR, bct.year & 0xff);
345 #ifdef USE_RTC_CENTURY
346 rtcout_locked(RTC_CENTURY, bct.year >> 8);
350 * Re-enable RTC updates and interrupts.
352 rtcout_locked(RTC_STATUSB, rtc_statusb);
353 rtcin_locked(RTC_INTR);
355 mtx_unlock_spin(&atrtc_lock);
356 mtx_unlock(&atrtc_time_lock);
362 atrtc_gettime(device_t dev, struct timespec *ts)
364 struct bcd_clocktime bct;
366 /* Look if we have a RTC present and the time is valid */
367 if (!(rtcin(RTC_STATUSD) & RTCSD_PWR)) {
368 device_printf(dev, "WARNING: Battery failure indication\n");
373 * wait for time update to complete
374 * If RTCSA_TUP is zero, we have at least 244us before next update.
375 * This is fast enough on most hardware, but a refinement would be
376 * to make sure that no more than 240us pass after we start reading,
377 * and try again if so.
379 mtx_lock(&atrtc_time_lock);
380 while (rtcin(RTC_STATUSA) & RTCSA_TUP)
382 mtx_lock_spin(&atrtc_lock);
383 bct.sec = rtcin_locked(RTC_SEC);
384 bct.min = rtcin_locked(RTC_MIN);
385 bct.hour = rtcin_locked(RTC_HRS);
386 bct.day = rtcin_locked(RTC_DAY);
387 bct.mon = rtcin_locked(RTC_MONTH);
388 bct.year = rtcin_locked(RTC_YEAR);
389 #ifdef USE_RTC_CENTURY
390 bct.year |= rtcin_locked(RTC_CENTURY) << 8;
392 mtx_unlock_spin(&atrtc_lock);
393 mtx_unlock(&atrtc_time_lock);
394 /* dow is unused in timespec conversion and we have no nsec info. */
397 clock_dbgprint_bcd(dev, CLOCK_DBG_READ, &bct);
398 return (clock_bcd_to_ts(&bct, ts, false));
401 static device_method_t atrtc_methods[] = {
402 /* Device interface */
403 DEVMETHOD(device_probe, atrtc_probe),
404 DEVMETHOD(device_attach, atrtc_attach),
405 DEVMETHOD(device_detach, bus_generic_detach),
406 DEVMETHOD(device_shutdown, bus_generic_shutdown),
407 DEVMETHOD(device_suspend, bus_generic_suspend),
408 /* XXX stop statclock? */
409 DEVMETHOD(device_resume, atrtc_resume),
411 /* clock interface */
412 DEVMETHOD(clock_gettime, atrtc_gettime),
413 DEVMETHOD(clock_settime, atrtc_settime),
418 static driver_t atrtc_driver = {
421 sizeof(struct atrtc_softc),
424 static devclass_t atrtc_devclass;
426 DRIVER_MODULE(atrtc, isa, atrtc_driver, atrtc_devclass, 0, 0);
427 DRIVER_MODULE(atrtc, acpi, atrtc_driver, atrtc_devclass, 0, 0);
428 ISA_PNP_INFO(atrtc_ids);