xref: /freebsd/sys/x86/isa/atrtc.c (revision 63d1fd5970ec814904aa0f4580b10a0d302d08b2)
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  * $FreeBSD$
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
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 */
412