atrtc.c revision 285446 
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: stable/10/sys/x86/isa/atrtc.c 285446 2015-07-13 11:58:08Z brueffer $
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: stable/10/sys/x86/isa/atrtc.c 285446 2015-07-13 11:58:08Z brueffer $");
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
59int	atrtcclock_disable = 0;
60
61static	int	rtc_reg = -1;
62static	u_char	rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
63static	u_char	rtc_statusb = RTCSB_24HR;
64
65/*
66 * RTC support routines
67 */
68
69int
70rtcin(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
86void
87writertc(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
102static __inline int
103readrtc(int port)
104{
105	return(bcd2bin(rtcin(port)));
106}
107
108static void
109atrtc_start(void)
110{
111
112	writertc(RTC_STATUSA, rtc_statusa);
113	writertc(RTC_STATUSB, RTCSB_24HR);
114}
115
116static void
117atrtc_rate(unsigned rate)
118{
119
120	rtc_statusa = RTCSA_DIVIDER | rate;
121	writertc(RTC_STATUSA, rtc_statusa);
122}
123
124static void
125atrtc_enable_intr(void)
126{
127
128	rtc_statusb |= RTCSB_PINTR;
129	writertc(RTC_STATUSB, rtc_statusb);
130	rtcin(RTC_INTR);
131}
132
133static void
134atrtc_disable_intr(void)
135{
136
137	rtc_statusb &= ~RTCSB_PINTR;
138	writertc(RTC_STATUSB, rtc_statusb);
139	rtcin(RTC_INTR);
140}
141
142void
143atrtc_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/**********************************************************************
155 * RTC driver for subr_rtc
156 */
157
158struct atrtc_softc {
159	int port_rid, intr_rid;
160	struct resource *port_res;
161	struct resource *intr_res;
162	void *intr_handler;
163	struct eventtimer et;
164};
165
166static int
167rtc_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
168{
169
170	atrtc_rate(max(fls(period + (period >> 1)) - 17, 1));
171	atrtc_enable_intr();
172	return (0);
173}
174
175static int
176rtc_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 */
204static int
205rtc_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 */
221static struct isa_pnp_id atrtc_ids[] = {
222	{ 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
223	{ 0 }
224};
225
226static int
227atrtc_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
240static int
241atrtc_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 = 0x00080000;
280		sc->et.et_max_period = 0x80000000;
281		sc->et.et_start = rtc_start;
282		sc->et.et_stop = rtc_stop;
283		sc->et.et_priv = dev;
284		et_register(&sc->et);
285	}
286	return(0);
287}
288
289static int
290atrtc_resume(device_t dev)
291{
292
293	atrtc_restore();
294	return(0);
295}
296
297static int
298atrtc_settime(device_t dev __unused, struct timespec *ts)
299{
300	struct clocktime ct;
301
302	clock_ts_to_ct(ts, &ct);
303
304	/* Disable RTC updates and interrupts. */
305	writertc(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR);
306
307	writertc(RTC_SEC, bin2bcd(ct.sec)); 		/* Write back Seconds */
308	writertc(RTC_MIN, bin2bcd(ct.min)); 		/* Write back Minutes */
309	writertc(RTC_HRS, bin2bcd(ct.hour));		/* Write back Hours   */
310
311	writertc(RTC_WDAY, ct.dow + 1);			/* Write back Weekday */
312	writertc(RTC_DAY, bin2bcd(ct.day));		/* Write back Day */
313	writertc(RTC_MONTH, bin2bcd(ct.mon));           /* Write back Month   */
314	writertc(RTC_YEAR, bin2bcd(ct.year % 100));	/* Write back Year    */
315#ifdef USE_RTC_CENTURY
316	writertc(RTC_CENTURY, bin2bcd(ct.year / 100));	/* ... and Century    */
317#endif
318
319	/* Reenable RTC updates and interrupts. */
320	writertc(RTC_STATUSB, rtc_statusb);
321	rtcin(RTC_INTR);
322	return (0);
323}
324
325static int
326atrtc_gettime(device_t dev, struct timespec *ts)
327{
328	struct clocktime ct;
329
330	/* Look if we have a RTC present and the time is valid */
331	if (!(rtcin(RTC_STATUSD) & RTCSD_PWR)) {
332		device_printf(dev, "WARNING: Battery failure indication\n");
333		return (EINVAL);
334	}
335
336	/*
337	 * wait for time update to complete
338	 * If RTCSA_TUP is zero, we have at least 244us before next update.
339	 * This is fast enough on most hardware, but a refinement would be
340	 * to make sure that no more than 240us pass after we start reading,
341	 * and try again if so.
342	 */
343	while (rtcin(RTC_STATUSA) & RTCSA_TUP)
344		continue;
345	critical_enter();
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 += (ct.year < 80 ? 2000 : 1900);
358#endif
359	critical_exit();
360	/* Set dow = -1 because some clocks don't set it correctly. */
361	ct.dow = -1;
362	return (clock_ct_to_ts(&ct, ts));
363}
364
365static device_method_t atrtc_methods[] = {
366	/* Device interface */
367	DEVMETHOD(device_probe,		atrtc_probe),
368	DEVMETHOD(device_attach,	atrtc_attach),
369	DEVMETHOD(device_detach,	bus_generic_detach),
370	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
371	DEVMETHOD(device_suspend,	bus_generic_suspend),
372		/* XXX stop statclock? */
373	DEVMETHOD(device_resume,	atrtc_resume),
374
375	/* clock interface */
376	DEVMETHOD(clock_gettime,	atrtc_gettime),
377	DEVMETHOD(clock_settime,	atrtc_settime),
378
379	{ 0, 0 }
380};
381
382static driver_t atrtc_driver = {
383	"atrtc",
384	atrtc_methods,
385	sizeof(struct atrtc_softc),
386};
387
388static devclass_t atrtc_devclass;
389
390DRIVER_MODULE(atrtc, isa, atrtc_driver, atrtc_devclass, 0, 0);
391DRIVER_MODULE(atrtc, acpi, atrtc_driver, atrtc_devclass, 0, 0);
392
393#include "opt_ddb.h"
394#ifdef DDB
395#include <ddb/ddb.h>
396
397DB_SHOW_COMMAND(rtc, rtc)
398{
399	printf("%02x/%02x/%02x %02x:%02x:%02x, A = %02x, B = %02x, C = %02x\n",
400		rtcin(RTC_YEAR), rtcin(RTC_MONTH), rtcin(RTC_DAY),
401		rtcin(RTC_HRS), rtcin(RTC_MIN), rtcin(RTC_SEC),
402		rtcin(RTC_STATUSA), rtcin(RTC_STATUSB), rtcin(RTC_INTR));
403}
404#endif /* DDB */
405