xref: /freebsd/sys/x86/isa/clock.c (revision cc16dea626cf2fc80cde667ac4798065108e596c)
1 /*-
2  * Copyright (c) 1990 The Regents of the University of California.
3  * Copyright (c) 2010 Alexander Motin <mav@FreeBSD.org>
4  * All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * William Jolitz and Don Ahn.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
34  */
35 
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 /*
40  * Routines to handle clock hardware.
41  */
42 
43 #include "opt_clock.h"
44 #include "opt_isa.h"
45 #include "opt_mca.h"
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/bus.h>
50 #include <sys/lock.h>
51 #include <sys/kdb.h>
52 #include <sys/mutex.h>
53 #include <sys/proc.h>
54 #include <sys/kernel.h>
55 #include <sys/module.h>
56 #include <sys/rman.h>
57 #include <sys/sched.h>
58 #include <sys/smp.h>
59 #include <sys/sysctl.h>
60 #include <sys/timeet.h>
61 #include <sys/timetc.h>
62 
63 #include <machine/clock.h>
64 #include <machine/cpu.h>
65 #include <machine/intr_machdep.h>
66 #include <machine/ppireg.h>
67 #include <machine/timerreg.h>
68 
69 #ifdef PC98
70 #include <pc98/pc98/pc98_machdep.h>
71 #else
72 #include <isa/rtc.h>
73 #endif
74 #ifdef DEV_ISA
75 #ifdef PC98
76 #include <pc98/cbus/cbus.h>
77 #else
78 #include <isa/isareg.h>
79 #endif
80 #include <isa/isavar.h>
81 #endif
82 
83 #ifdef DEV_MCA
84 #include <i386/bios/mca_machdep.h>
85 #endif
86 
87 int	clkintr_pending;
88 #ifndef TIMER_FREQ
89 #ifdef PC98
90 #define TIMER_FREQ   2457600
91 #else
92 #define TIMER_FREQ   1193182
93 #endif
94 #endif
95 u_int	i8254_freq = TIMER_FREQ;
96 TUNABLE_INT("hw.i8254.freq", &i8254_freq);
97 int	i8254_max_count;
98 static int i8254_timecounter = 1;
99 
100 struct mtx clock_lock;
101 static	struct intsrc *i8254_intsrc;
102 static	uint16_t i8254_lastcount;
103 static	uint16_t i8254_offset;
104 static	int	(*i8254_pending)(struct intsrc *);
105 static	int	i8254_ticked;
106 
107 struct attimer_softc {
108 	int intr_en;
109 	int port_rid, intr_rid;
110 	struct resource *port_res;
111 	struct resource *intr_res;
112 #ifdef PC98
113 	int port_rid2;
114 	struct resource *port_res2;
115 #endif
116 	void *intr_handler;
117 	struct timecounter tc;
118 	struct eventtimer et;
119 	int		mode;
120 #define	MODE_STOP	0
121 #define	MODE_PERIODIC	1
122 #define	MODE_ONESHOT	2
123 	uint32_t	period;
124 };
125 static struct attimer_softc *attimer_sc = NULL;
126 
127 static int timer0_period = -2;
128 static int timer0_mode = 0xffff;
129 static int timer0_last = 0xffff;
130 
131 /* Values for timerX_state: */
132 #define	RELEASED	0
133 #define	RELEASE_PENDING	1
134 #define	ACQUIRED	2
135 #define	ACQUIRE_PENDING	3
136 
137 static	u_char	timer2_state;
138 
139 static	unsigned i8254_get_timecount(struct timecounter *tc);
140 static	void	set_i8254_freq(int mode, uint32_t period);
141 
142 static int
143 clkintr(void *arg)
144 {
145 	struct attimer_softc *sc = (struct attimer_softc *)arg;
146 
147 	if (i8254_timecounter && sc->period != 0) {
148 		mtx_lock_spin(&clock_lock);
149 		if (i8254_ticked)
150 			i8254_ticked = 0;
151 		else {
152 			i8254_offset += i8254_max_count;
153 			i8254_lastcount = 0;
154 		}
155 		clkintr_pending = 0;
156 		mtx_unlock_spin(&clock_lock);
157 	}
158 
159 	if (sc && sc->et.et_active && sc->mode != MODE_STOP)
160 		sc->et.et_event_cb(&sc->et, sc->et.et_arg);
161 
162 #ifdef DEV_MCA
163 	/* Reset clock interrupt by asserting bit 7 of port 0x61 */
164 	if (MCA_system)
165 		outb(0x61, inb(0x61) | 0x80);
166 #endif
167 	return (FILTER_HANDLED);
168 }
169 
170 int
171 timer_spkr_acquire(void)
172 {
173 	int mode;
174 
175 #ifdef PC98
176 	mode = TIMER_SEL1 | TIMER_SQWAVE | TIMER_16BIT;
177 #else
178 	mode = TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT;
179 #endif
180 
181 	if (timer2_state != RELEASED)
182 		return (-1);
183 	timer2_state = ACQUIRED;
184 
185 	/*
186 	 * This access to the timer registers is as atomic as possible
187 	 * because it is a single instruction.  We could do better if we
188 	 * knew the rate.  Use of splclock() limits glitches to 10-100us,
189 	 * and this is probably good enough for timer2, so we aren't as
190 	 * careful with it as with timer0.
191 	 */
192 #ifdef PC98
193 	outb(TIMER_MODE, TIMER_SEL1 | (mode & 0x3f));
194 #else
195 	outb(TIMER_MODE, TIMER_SEL2 | (mode & 0x3f));
196 #endif
197 	ppi_spkr_on();		/* enable counter2 output to speaker */
198 	return (0);
199 }
200 
201 int
202 timer_spkr_release(void)
203 {
204 
205 	if (timer2_state != ACQUIRED)
206 		return (-1);
207 	timer2_state = RELEASED;
208 #ifdef PC98
209 	outb(TIMER_MODE, TIMER_SEL1 | TIMER_SQWAVE | TIMER_16BIT);
210 #else
211 	outb(TIMER_MODE, TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT);
212 #endif
213 	ppi_spkr_off();		/* disable counter2 output to speaker */
214 	return (0);
215 }
216 
217 void
218 timer_spkr_setfreq(int freq)
219 {
220 
221 	freq = i8254_freq / freq;
222 	mtx_lock_spin(&clock_lock);
223 #ifdef PC98
224 	outb(TIMER_CNTR1, freq & 0xff);
225 	outb(TIMER_CNTR1, freq >> 8);
226 #else
227 	outb(TIMER_CNTR2, freq & 0xff);
228 	outb(TIMER_CNTR2, freq >> 8);
229 #endif
230 	mtx_unlock_spin(&clock_lock);
231 }
232 
233 static int
234 getit(void)
235 {
236 	int high, low;
237 
238 	mtx_lock_spin(&clock_lock);
239 
240 	/* Select timer0 and latch counter value. */
241 	outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
242 
243 	low = inb(TIMER_CNTR0);
244 	high = inb(TIMER_CNTR0);
245 
246 	mtx_unlock_spin(&clock_lock);
247 	return ((high << 8) | low);
248 }
249 
250 #ifndef DELAYDEBUG
251 static u_int
252 get_tsc(__unused struct timecounter *tc)
253 {
254 
255 	return (rdtsc32());
256 }
257 
258 static __inline int
259 delay_tc(int n)
260 {
261 	struct timecounter *tc;
262 	timecounter_get_t *func;
263 	uint64_t end, freq, now;
264 	u_int last, mask, u;
265 
266 	tc = timecounter;
267 	freq = atomic_load_acq_64(&tsc_freq);
268 	if (tsc_is_invariant && freq != 0) {
269 		func = get_tsc;
270 		mask = ~0u;
271 	} else {
272 		if (tc->tc_quality <= 0)
273 			return (0);
274 		func = tc->tc_get_timecount;
275 		mask = tc->tc_counter_mask;
276 		freq = tc->tc_frequency;
277 	}
278 	now = 0;
279 	end = freq * n / 1000000;
280 	if (func == get_tsc)
281 		sched_pin();
282 	last = func(tc) & mask;
283 	do {
284 		cpu_spinwait();
285 		u = func(tc) & mask;
286 		if (u < last)
287 			now += mask - last + u + 1;
288 		else
289 			now += u - last;
290 		last = u;
291 	} while (now < end);
292 	if (func == get_tsc)
293 		sched_unpin();
294 	return (1);
295 }
296 #endif
297 
298 /*
299  * Wait "n" microseconds.
300  * Relies on timer 1 counting down from (i8254_freq / hz)
301  * Note: timer had better have been programmed before this is first used!
302  */
303 void
304 DELAY(int n)
305 {
306 	int delta, prev_tick, tick, ticks_left;
307 #ifdef DELAYDEBUG
308 	int getit_calls = 1;
309 	int n1;
310 	static int state = 0;
311 
312 	if (state == 0) {
313 		state = 1;
314 		for (n1 = 1; n1 <= 10000000; n1 *= 10)
315 			DELAY(n1);
316 		state = 2;
317 	}
318 	if (state == 1)
319 		printf("DELAY(%d)...", n);
320 #else
321 	if (delay_tc(n))
322 		return;
323 #endif
324 	/*
325 	 * Read the counter first, so that the rest of the setup overhead is
326 	 * counted.  Guess the initial overhead is 20 usec (on most systems it
327 	 * takes about 1.5 usec for each of the i/o's in getit().  The loop
328 	 * takes about 6 usec on a 486/33 and 13 usec on a 386/20.  The
329 	 * multiplications and divisions to scale the count take a while).
330 	 *
331 	 * However, if ddb is active then use a fake counter since reading
332 	 * the i8254 counter involves acquiring a lock.  ddb must not do
333 	 * locking for many reasons, but it calls here for at least atkbd
334 	 * input.
335 	 */
336 #ifdef KDB
337 	if (kdb_active)
338 		prev_tick = 1;
339 	else
340 #endif
341 		prev_tick = getit();
342 	n -= 0;			/* XXX actually guess no initial overhead */
343 	/*
344 	 * Calculate (n * (i8254_freq / 1e6)) without using floating point
345 	 * and without any avoidable overflows.
346 	 */
347 	if (n <= 0)
348 		ticks_left = 0;
349 	else if (n < 256)
350 		/*
351 		 * Use fixed point to avoid a slow division by 1000000.
352 		 * 39099 = 1193182 * 2^15 / 10^6 rounded to nearest.
353 		 * 2^15 is the first power of 2 that gives exact results
354 		 * for n between 0 and 256.
355 		 */
356 		ticks_left = ((u_int)n * 39099 + (1 << 15) - 1) >> 15;
357 	else
358 		/*
359 		 * Don't bother using fixed point, although gcc-2.7.2
360 		 * generates particularly poor code for the long long
361 		 * division, since even the slow way will complete long
362 		 * before the delay is up (unless we're interrupted).
363 		 */
364 		ticks_left = ((u_int)n * (long long)i8254_freq + 999999)
365 			     / 1000000;
366 
367 	while (ticks_left > 0) {
368 #ifdef KDB
369 		if (kdb_active) {
370 #ifdef PC98
371 			outb(0x5f, 0);
372 #else
373 			inb(0x84);
374 #endif
375 			tick = prev_tick - 1;
376 			if (tick <= 0)
377 				tick = i8254_max_count;
378 		} else
379 #endif
380 			tick = getit();
381 #ifdef DELAYDEBUG
382 		++getit_calls;
383 #endif
384 		delta = prev_tick - tick;
385 		prev_tick = tick;
386 		if (delta < 0) {
387 			delta += i8254_max_count;
388 			/*
389 			 * Guard against i8254_max_count being wrong.
390 			 * This shouldn't happen in normal operation,
391 			 * but it may happen if set_i8254_freq() is
392 			 * traced.
393 			 */
394 			if (delta < 0)
395 				delta = 0;
396 		}
397 		ticks_left -= delta;
398 	}
399 #ifdef DELAYDEBUG
400 	if (state == 1)
401 		printf(" %d calls to getit() at %d usec each\n",
402 		       getit_calls, (n + 5) / getit_calls);
403 #endif
404 }
405 
406 static void
407 set_i8254_freq(int mode, uint32_t period)
408 {
409 	int new_count, new_mode;
410 
411 	mtx_lock_spin(&clock_lock);
412 	if (mode == MODE_STOP) {
413 		if (i8254_timecounter) {
414 			mode = MODE_PERIODIC;
415 			new_count = 0x10000;
416 		} else
417 			new_count = -1;
418 	} else {
419 		new_count = min(((uint64_t)i8254_freq * period +
420 		    0x80000000LLU) >> 32, 0x10000);
421 	}
422 	if (new_count == timer0_period)
423 		goto out;
424 	i8254_max_count = ((new_count & ~0xffff) != 0) ? 0xffff : new_count;
425 	timer0_period = (mode == MODE_PERIODIC) ? new_count : -1;
426 	switch (mode) {
427 	case MODE_STOP:
428 		new_mode = TIMER_SEL0 | TIMER_INTTC | TIMER_16BIT;
429 		outb(TIMER_MODE, new_mode);
430 		outb(TIMER_CNTR0, 0);
431 		outb(TIMER_CNTR0, 0);
432 		break;
433 	case MODE_PERIODIC:
434 		new_mode = TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT;
435 		outb(TIMER_MODE, new_mode);
436 		outb(TIMER_CNTR0, new_count & 0xff);
437 		outb(TIMER_CNTR0, new_count >> 8);
438 		break;
439 	case MODE_ONESHOT:
440 		if (new_count < 256 && timer0_last < 256) {
441 			new_mode = TIMER_SEL0 | TIMER_INTTC | TIMER_LSB;
442 			if (new_mode != timer0_mode)
443 				outb(TIMER_MODE, new_mode);
444 			outb(TIMER_CNTR0, new_count & 0xff);
445 			break;
446 		}
447 		new_mode = TIMER_SEL0 | TIMER_INTTC | TIMER_16BIT;
448 		if (new_mode != timer0_mode)
449 			outb(TIMER_MODE, new_mode);
450 		outb(TIMER_CNTR0, new_count & 0xff);
451 		outb(TIMER_CNTR0, new_count >> 8);
452 		break;
453 	default:
454 		panic("set_i8254_freq: unknown operational mode");
455 	}
456 	timer0_mode = new_mode;
457 	timer0_last = new_count;
458 out:
459 	mtx_unlock_spin(&clock_lock);
460 }
461 
462 static void
463 i8254_restore(void)
464 {
465 
466 	timer0_period = -2;
467 	timer0_mode = 0xffff;
468 	timer0_last = 0xffff;
469 	if (attimer_sc != NULL)
470 		set_i8254_freq(attimer_sc->mode, attimer_sc->period);
471 	else
472 		set_i8254_freq(MODE_STOP, 0);
473 }
474 
475 #ifndef __amd64__
476 /*
477  * Restore all the timers non-atomically (XXX: should be atomically).
478  *
479  * This function is called from pmtimer_resume() to restore all the timers.
480  * This should not be necessary, but there are broken laptops that do not
481  * restore all the timers on resume. The APM spec was at best vague on the
482  * subject.
483  * pmtimer is used only with the old APM power management, and not with
484  * acpi, which is required for amd64, so skip it in that case.
485  */
486 void
487 timer_restore(void)
488 {
489 
490 	i8254_restore();		/* restore i8254_freq and hz */
491 #ifndef PC98
492 	atrtc_restore();		/* reenable RTC interrupts */
493 #endif
494 }
495 #endif
496 
497 /* This is separate from startrtclock() so that it can be called early. */
498 void
499 i8254_init(void)
500 {
501 
502 	mtx_init(&clock_lock, "clk", NULL, MTX_SPIN | MTX_NOPROFILE);
503 #ifdef PC98
504 	if (pc98_machine_type & M_8M)
505 		i8254_freq = 1996800L; /* 1.9968 MHz */
506 #endif
507 	set_i8254_freq(MODE_STOP, 0);
508 }
509 
510 void
511 startrtclock()
512 {
513 
514 	init_TSC();
515 }
516 
517 void
518 cpu_initclocks(void)
519 {
520 
521 	cpu_initclocks_bsp();
522 }
523 
524 static int
525 sysctl_machdep_i8254_freq(SYSCTL_HANDLER_ARGS)
526 {
527 	int error;
528 	u_int freq;
529 
530 	/*
531 	 * Use `i8254' instead of `timer' in external names because `timer'
532 	 * is too generic.  Should use it everywhere.
533 	 */
534 	freq = i8254_freq;
535 	error = sysctl_handle_int(oidp, &freq, 0, req);
536 	if (error == 0 && req->newptr != NULL) {
537 		i8254_freq = freq;
538 		if (attimer_sc != NULL) {
539 			set_i8254_freq(attimer_sc->mode, attimer_sc->period);
540 			attimer_sc->tc.tc_frequency = freq;
541 		} else {
542 			set_i8254_freq(MODE_STOP, 0);
543 		}
544 	}
545 	return (error);
546 }
547 
548 SYSCTL_PROC(_machdep, OID_AUTO, i8254_freq, CTLTYPE_INT | CTLFLAG_RW,
549     0, sizeof(u_int), sysctl_machdep_i8254_freq, "IU",
550     "i8254 timer frequency");
551 
552 static unsigned
553 i8254_get_timecount(struct timecounter *tc)
554 {
555 	device_t dev = (device_t)tc->tc_priv;
556 	struct attimer_softc *sc = device_get_softc(dev);
557 	register_t flags;
558 	uint16_t count;
559 	u_int high, low;
560 
561 	if (sc->period == 0)
562 		return (i8254_max_count - getit());
563 
564 #ifdef __amd64__
565 	flags = read_rflags();
566 #else
567 	flags = read_eflags();
568 #endif
569 	mtx_lock_spin(&clock_lock);
570 
571 	/* Select timer0 and latch counter value. */
572 	outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
573 
574 	low = inb(TIMER_CNTR0);
575 	high = inb(TIMER_CNTR0);
576 	count = i8254_max_count - ((high << 8) | low);
577 	if (count < i8254_lastcount ||
578 	    (!i8254_ticked && (clkintr_pending ||
579 	    ((count < 20 || (!(flags & PSL_I) &&
580 	    count < i8254_max_count / 2u)) &&
581 	    i8254_pending != NULL && i8254_pending(i8254_intsrc))))) {
582 		i8254_ticked = 1;
583 		i8254_offset += i8254_max_count;
584 	}
585 	i8254_lastcount = count;
586 	count += i8254_offset;
587 	mtx_unlock_spin(&clock_lock);
588 	return (count);
589 }
590 
591 static int
592 attimer_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
593 {
594 	device_t dev = (device_t)et->et_priv;
595 	struct attimer_softc *sc = device_get_softc(dev);
596 
597 	if (period != 0) {
598 		sc->mode = MODE_PERIODIC;
599 		sc->period = period;
600 	} else {
601 		sc->mode = MODE_ONESHOT;
602 		sc->period = first;
603 	}
604 	if (!sc->intr_en) {
605 		i8254_intsrc->is_pic->pic_enable_source(i8254_intsrc);
606 		sc->intr_en = 1;
607 	}
608 	set_i8254_freq(sc->mode, sc->period);
609 	return (0);
610 }
611 
612 static int
613 attimer_stop(struct eventtimer *et)
614 {
615 	device_t dev = (device_t)et->et_priv;
616 	struct attimer_softc *sc = device_get_softc(dev);
617 
618 	sc->mode = MODE_STOP;
619 	sc->period = 0;
620 	set_i8254_freq(sc->mode, sc->period);
621 	return (0);
622 }
623 
624 #ifdef DEV_ISA
625 /*
626  * Attach to the ISA PnP descriptors for the timer
627  */
628 static struct isa_pnp_id attimer_ids[] = {
629 	{ 0x0001d041 /* PNP0100 */, "AT timer" },
630 	{ 0 }
631 };
632 
633 #ifdef PC98
634 static void
635 pc98_alloc_resource(device_t dev)
636 {
637 	static bus_addr_t iat1[] = {0, 2, 4, 6};
638 	static bus_addr_t iat2[] = {0, 4};
639 	struct attimer_softc *sc;
640 
641 	sc = device_get_softc(dev);
642 
643 	sc->port_rid = 0;
644 	bus_set_resource(dev, SYS_RES_IOPORT, sc->port_rid, IO_TIMER1, 1);
645 	sc->port_res = isa_alloc_resourcev(dev, SYS_RES_IOPORT,
646 	    &sc->port_rid, iat1, 4, RF_ACTIVE);
647 	if (sc->port_res == NULL)
648 		device_printf(dev, "Warning: Couldn't map I/O.\n");
649 	else
650 		isa_load_resourcev(sc->port_res, iat1, 4);
651 
652 	sc->port_rid2 = 4;
653 	bus_set_resource(dev, SYS_RES_IOPORT, sc->port_rid2, TIMER_CNTR1, 1);
654 	sc->port_res2 = isa_alloc_resourcev(dev, SYS_RES_IOPORT,
655 	    &sc->port_rid2, iat2, 2, RF_ACTIVE);
656 	if (sc->port_res2 == NULL)
657 		device_printf(dev, "Warning: Couldn't map I/O.\n");
658 	else
659 		isa_load_resourcev(sc->port_res2, iat2, 2);
660 }
661 
662 static void
663 pc98_release_resource(device_t dev)
664 {
665 	struct attimer_softc *sc;
666 
667 	sc = device_get_softc(dev);
668 
669 	if (sc->port_res)
670 		bus_release_resource(dev, SYS_RES_IOPORT, sc->port_rid,
671 		    sc->port_res);
672 	if (sc->port_res2)
673 		bus_release_resource(dev, SYS_RES_IOPORT, sc->port_rid2,
674 		    sc->port_res2);
675 }
676 #endif
677 
678 static int
679 attimer_probe(device_t dev)
680 {
681 	int result;
682 
683 	result = ISA_PNP_PROBE(device_get_parent(dev), dev, attimer_ids);
684 	/* ENOENT means no PnP-ID, device is hinted. */
685 	if (result == ENOENT) {
686 		device_set_desc(dev, "AT timer");
687 #ifdef PC98
688 		/* To print resources correctly. */
689 		pc98_alloc_resource(dev);
690 		pc98_release_resource(dev);
691 #endif
692 		return (BUS_PROBE_LOW_PRIORITY);
693 	}
694 	return (result);
695 }
696 
697 static int
698 attimer_attach(device_t dev)
699 {
700 	struct attimer_softc *sc;
701 	u_long s;
702 	int i;
703 
704 	attimer_sc = sc = device_get_softc(dev);
705 	bzero(sc, sizeof(struct attimer_softc));
706 #ifdef PC98
707 	pc98_alloc_resource(dev);
708 #else
709 	if (!(sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT,
710 	    &sc->port_rid, IO_TIMER1, IO_TIMER1 + 3, 4, RF_ACTIVE)))
711 		device_printf(dev,"Warning: Couldn't map I/O.\n");
712 #endif
713 	i8254_intsrc = intr_lookup_source(0);
714 	if (i8254_intsrc != NULL)
715 		i8254_pending = i8254_intsrc->is_pic->pic_source_pending;
716 	resource_int_value(device_get_name(dev), device_get_unit(dev),
717 	    "timecounter", &i8254_timecounter);
718 	set_i8254_freq(MODE_STOP, 0);
719 	if (i8254_timecounter) {
720 		sc->tc.tc_get_timecount = i8254_get_timecount;
721 		sc->tc.tc_counter_mask = 0xffff;
722 		sc->tc.tc_frequency = i8254_freq;
723 		sc->tc.tc_name = "i8254";
724 		sc->tc.tc_quality = 0;
725 		sc->tc.tc_priv = dev;
726 		tc_init(&sc->tc);
727 	}
728 	if (resource_int_value(device_get_name(dev), device_get_unit(dev),
729 	    "clock", &i) != 0 || i != 0) {
730 	    	sc->intr_rid = 0;
731 		while (bus_get_resource(dev, SYS_RES_IRQ, sc->intr_rid,
732 		    &s, NULL) == 0 && s != 0)
733 			sc->intr_rid++;
734 		if (!(sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
735 		    &sc->intr_rid, 0, 0, 1, RF_ACTIVE))) {
736 			device_printf(dev,"Can't map interrupt.\n");
737 			return (0);
738 		}
739 		/* Dirty hack, to make bus_setup_intr to not enable source. */
740 		i8254_intsrc->is_handlers++;
741 		if ((bus_setup_intr(dev, sc->intr_res,
742 		    INTR_MPSAFE | INTR_TYPE_CLK,
743 		    (driver_filter_t *)clkintr, NULL,
744 		    sc, &sc->intr_handler))) {
745 			device_printf(dev, "Can't setup interrupt.\n");
746 			i8254_intsrc->is_handlers--;
747 			return (0);
748 		}
749 		i8254_intsrc->is_handlers--;
750 		i8254_intsrc->is_pic->pic_enable_intr(i8254_intsrc);
751 		sc->et.et_name = "i8254";
752 		sc->et.et_flags = ET_FLAGS_PERIODIC;
753 		if (!i8254_timecounter)
754 			sc->et.et_flags |= ET_FLAGS_ONESHOT;
755 		sc->et.et_quality = 100;
756 		sc->et.et_frequency = i8254_freq;
757 		sc->et.et_min_period = (0x0002LLU << 32) / i8254_freq;
758 		sc->et.et_max_period = (0xfffeLLU << 32) / i8254_freq;
759 		sc->et.et_start = attimer_start;
760 		sc->et.et_stop = attimer_stop;
761 		sc->et.et_priv = dev;
762 		et_register(&sc->et);
763 	}
764 	return(0);
765 }
766 
767 static int
768 attimer_resume(device_t dev)
769 {
770 
771 	i8254_restore();
772 	return (0);
773 }
774 
775 static device_method_t attimer_methods[] = {
776 	/* Device interface */
777 	DEVMETHOD(device_probe,		attimer_probe),
778 	DEVMETHOD(device_attach,	attimer_attach),
779 	DEVMETHOD(device_detach,	bus_generic_detach),
780 	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
781 	DEVMETHOD(device_suspend,	bus_generic_suspend),
782 	DEVMETHOD(device_resume,	attimer_resume),
783 	{ 0, 0 }
784 };
785 
786 static driver_t attimer_driver = {
787 	"attimer",
788 	attimer_methods,
789 	sizeof(struct attimer_softc),
790 };
791 
792 static devclass_t attimer_devclass;
793 
794 DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0);
795 DRIVER_MODULE(attimer, acpi, attimer_driver, attimer_devclass, 0, 0);
796 
797 #endif /* DEV_ISA */
798