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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
129 /* Values for timerX_state: */
130 #define RELEASED        0
131 #define RELEASE_PENDING 1
132 #define ACQUIRED        2
133 #define ACQUIRE_PENDING 3
134
135 static  u_char  timer2_state;
136
137 static  unsigned i8254_get_timecount(struct timecounter *tc);
138 static  void    set_i8254_freq(int mode, uint32_t period);
139
140 static int
141 clkintr(void *arg)
142 {
143         struct attimer_softc *sc = (struct attimer_softc *)arg;
144
145         if (i8254_timecounter && sc->period != 0) {
146                 mtx_lock_spin(&clock_lock);
147                 if (i8254_ticked)
148                         i8254_ticked = 0;
149                 else {
150                         i8254_offset += i8254_max_count;
151                         i8254_lastcount = 0;
152                 }
153                 clkintr_pending = 0;
154                 mtx_unlock_spin(&clock_lock);
155         }
156
157         if (sc && sc->et.et_active && sc->mode != MODE_STOP)
158                 sc->et.et_event_cb(&sc->et, sc->et.et_arg);
159
160 #ifdef DEV_MCA
161         /* Reset clock interrupt by asserting bit 7 of port 0x61 */
162         if (MCA_system)
163                 outb(0x61, inb(0x61) | 0x80);
164 #endif
165         return (FILTER_HANDLED);
166 }
167
168 int
169 timer_spkr_acquire(void)
170 {
171         int mode;
172
173 #ifdef PC98
174         mode = TIMER_SEL1 | TIMER_SQWAVE | TIMER_16BIT;
175 #else
176         mode = TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT;
177 #endif
178
179         if (timer2_state != RELEASED)
180                 return (-1);
181         timer2_state = ACQUIRED;
182
183         /*
184          * This access to the timer registers is as atomic as possible
185          * because it is a single instruction.  We could do better if we
186          * knew the rate.  Use of splclock() limits glitches to 10-100us,
187          * and this is probably good enough for timer2, so we aren't as
188          * careful with it as with timer0.
189          */
190 #ifdef PC98
191         outb(TIMER_MODE, TIMER_SEL1 | (mode & 0x3f));
192 #else
193         outb(TIMER_MODE, TIMER_SEL2 | (mode & 0x3f));
194 #endif
195         ppi_spkr_on();          /* enable counter2 output to speaker */
196         return (0);
197 }
198
199 int
200 timer_spkr_release(void)
201 {
202
203         if (timer2_state != ACQUIRED)
204                 return (-1);
205         timer2_state = RELEASED;
206 #ifdef PC98
207         outb(TIMER_MODE, TIMER_SEL1 | TIMER_SQWAVE | TIMER_16BIT);
208 #else
209         outb(TIMER_MODE, TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT);
210 #endif
211         ppi_spkr_off();         /* disable counter2 output to speaker */
212         return (0);
213 }
214
215 void
216 timer_spkr_setfreq(int freq)
217 {
218
219         freq = i8254_freq / freq;
220         mtx_lock_spin(&clock_lock);
221 #ifdef PC98
222         outb(TIMER_CNTR1, freq & 0xff);
223         outb(TIMER_CNTR1, freq >> 8);
224 #else
225         outb(TIMER_CNTR2, freq & 0xff);
226         outb(TIMER_CNTR2, freq >> 8);
227 #endif
228         mtx_unlock_spin(&clock_lock);
229 }
230
231 static int
232 getit(void)
233 {
234         int high, low;
235
236         mtx_lock_spin(&clock_lock);
237
238         /* Select timer0 and latch counter value. */
239         outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
240
241         low = inb(TIMER_CNTR0);
242         high = inb(TIMER_CNTR0);
243
244         mtx_unlock_spin(&clock_lock);
245         return ((high << 8) | low);
246 }
247
248 #ifndef DELAYDEBUG
249 static u_int
250 get_tsc(__unused struct timecounter *tc)
251 {
252
253         return (rdtsc32());
254 }
255
256 static __inline int
257 delay_tc(int n)
258 {
259         struct timecounter *tc;
260         timecounter_get_t *func;
261         uint64_t end, freq, now;
262         u_int last, mask, u;
263
264         tc = timecounter;
265         freq = atomic_load_acq_64(&tsc_freq);
266         if (tsc_is_invariant && freq != 0) {
267                 func = get_tsc;
268                 mask = ~0u;
269         } else {
270                 if (tc->tc_quality <= 0)
271                         return (0);
272                 func = tc->tc_get_timecount;
273                 mask = tc->tc_counter_mask;
274                 freq = tc->tc_frequency;
275         }
276         now = 0;
277         end = freq * n / 1000000;
278         if (func == get_tsc)
279                 sched_pin();
280         last = func(tc) & mask;
281         do {
282                 cpu_spinwait();
283                 u = func(tc) & mask;
284                 if (u < last)
285                         now += mask - last + u + 1;
286                 else
287                         now += u - last;
288                 last = u;
289         } while (now < end);
290         if (func == get_tsc)
291                 sched_unpin();
292         return (1);
293 }
294 #endif
295
296 /*
297  * Wait "n" microseconds.
298  * Relies on timer 1 counting down from (i8254_freq / hz)
299  * Note: timer had better have been programmed before this is first used!
300  */
301 void
302 DELAY(int n)
303 {
304         int delta, prev_tick, tick, ticks_left;
305 #ifdef DELAYDEBUG
306         int getit_calls = 1;
307         int n1;
308         static int state = 0;
309
310         if (state == 0) {
311                 state = 1;
312                 for (n1 = 1; n1 <= 10000000; n1 *= 10)
313                         DELAY(n1);
314                 state = 2;
315         }
316         if (state == 1)
317                 printf("DELAY(%d)...", n);
318 #else
319         if (delay_tc(n))
320                 return;
321 #endif
322         /*
323          * Read the counter first, so that the rest of the setup overhead is
324          * counted.  Guess the initial overhead is 20 usec (on most systems it
325          * takes about 1.5 usec for each of the i/o's in getit().  The loop
326          * takes about 6 usec on a 486/33 and 13 usec on a 386/20.  The
327          * multiplications and divisions to scale the count take a while).
328          *
329          * However, if ddb is active then use a fake counter since reading
330          * the i8254 counter involves acquiring a lock.  ddb must not do
331          * locking for many reasons, but it calls here for at least atkbd
332          * input.
333          */
334 #ifdef KDB
335         if (kdb_active)
336                 prev_tick = 1;
337         else
338 #endif
339                 prev_tick = getit();
340         n -= 0;                 /* XXX actually guess no initial overhead */
341         /*
342          * Calculate (n * (i8254_freq / 1e6)) without using floating point
343          * and without any avoidable overflows.
344          */
345         if (n <= 0)
346                 ticks_left = 0;
347         else if (n < 256)
348                 /*
349                  * Use fixed point to avoid a slow division by 1000000.
350                  * 39099 = 1193182 * 2^15 / 10^6 rounded to nearest.
351                  * 2^15 is the first power of 2 that gives exact results
352                  * for n between 0 and 256.
353                  */
354                 ticks_left = ((u_int)n * 39099 + (1 << 15) - 1) >> 15;
355         else
356                 /*
357                  * Don't bother using fixed point, although gcc-2.7.2
358                  * generates particularly poor code for the long long
359                  * division, since even the slow way will complete long
360                  * before the delay is up (unless we're interrupted).
361                  */
362                 ticks_left = ((u_int)n * (long long)i8254_freq + 999999)
363                              / 1000000;
364
365         while (ticks_left > 0) {
366 #ifdef KDB
367                 if (kdb_active) {
368 #ifdef PC98
369                         outb(0x5f, 0);
370 #else
371                         inb(0x84);
372 #endif
373                         tick = prev_tick - 1;
374                         if (tick <= 0)
375                                 tick = i8254_max_count;
376                 } else
377 #endif
378                         tick = getit();
379 #ifdef DELAYDEBUG
380                 ++getit_calls;
381 #endif
382                 delta = prev_tick - tick;
383                 prev_tick = tick;
384                 if (delta < 0) {
385                         delta += i8254_max_count;
386                         /*
387                          * Guard against i8254_max_count being wrong.
388                          * This shouldn't happen in normal operation,
389                          * but it may happen if set_i8254_freq() is
390                          * traced.
391                          */
392                         if (delta < 0)
393                                 delta = 0;
394                 }
395                 ticks_left -= delta;
396         }
397 #ifdef DELAYDEBUG
398         if (state == 1)
399                 printf(" %d calls to getit() at %d usec each\n",
400                        getit_calls, (n + 5) / getit_calls);
401 #endif
402 }
403
404 static void
405 set_i8254_freq(int mode, uint32_t period)
406 {
407         int new_count;
408
409         mtx_lock_spin(&clock_lock);
410         if (mode == MODE_STOP) {
411                 if (i8254_timecounter) {
412                         mode = MODE_PERIODIC;
413                         new_count = 0x10000;
414                 } else
415                         new_count = -1;
416         } else {
417                 new_count = min(((uint64_t)i8254_freq * period +
418                     0x80000000LLU) >> 32, 0x10000);
419         }
420         if (new_count == timer0_period)
421                 goto out;
422         i8254_max_count = ((new_count & ~0xffff) != 0) ? 0xffff : new_count;
423         timer0_period = (mode == MODE_PERIODIC) ? new_count : -1;
424         switch (mode) {
425         case MODE_STOP:
426                 outb(TIMER_MODE, TIMER_SEL0 | TIMER_INTTC | TIMER_16BIT);
427                 outb(TIMER_CNTR0, 0);
428                 outb(TIMER_CNTR0, 0);
429                 break;
430         case MODE_PERIODIC:
431                 outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
432                 outb(TIMER_CNTR0, new_count & 0xff);
433                 outb(TIMER_CNTR0, new_count >> 8);
434                 break;
435         case MODE_ONESHOT:
436                 outb(TIMER_MODE, TIMER_SEL0 | TIMER_INTTC | TIMER_16BIT);
437                 outb(TIMER_CNTR0, new_count & 0xff);
438                 outb(TIMER_CNTR0, new_count >> 8);
439                 break;
440         }
441 out:
442         mtx_unlock_spin(&clock_lock);
443 }
444
445 static void
446 i8254_restore(void)
447 {
448
449         timer0_period = -2;
450         if (attimer_sc != NULL)
451                 set_i8254_freq(attimer_sc->mode, attimer_sc->period);
452         else
453                 set_i8254_freq(0, 0);
454 }
455
456 #ifndef __amd64__
457 /*
458  * Restore all the timers non-atomically (XXX: should be atomically).
459  *
460  * This function is called from pmtimer_resume() to restore all the timers.
461  * This should not be necessary, but there are broken laptops that do not
462  * restore all the timers on resume.
463  * As long as pmtimer is not part of amd64 suport, skip this for the amd64
464  * case.
465  */
466 void
467 timer_restore(void)
468 {
469
470         i8254_restore();                /* restore i8254_freq and hz */
471 #ifndef PC98
472         atrtc_restore();                /* reenable RTC interrupts */
473 #endif
474 }
475 #endif
476
477 /* This is separate from startrtclock() so that it can be called early. */
478 void
479 i8254_init(void)
480 {
481
482         mtx_init(&clock_lock, "clk", NULL, MTX_SPIN | MTX_NOPROFILE);
483 #ifdef PC98
484         if (pc98_machine_type & M_8M)
485                 i8254_freq = 1996800L; /* 1.9968 MHz */
486 #endif
487         set_i8254_freq(0, 0);
488 }
489
490 void
491 startrtclock()
492 {
493
494         init_TSC();
495 }
496
497 void
498 cpu_initclocks(void)
499 {
500
501         cpu_initclocks_bsp();
502 }
503
504 static int
505 sysctl_machdep_i8254_freq(SYSCTL_HANDLER_ARGS)
506 {
507         int error;
508         u_int freq;
509
510         /*
511          * Use `i8254' instead of `timer' in external names because `timer'
512          * is too generic.  Should use it everywhere.
513          */
514         freq = i8254_freq;
515         error = sysctl_handle_int(oidp, &freq, 0, req);
516         if (error == 0 && req->newptr != NULL) {
517                 i8254_freq = freq;
518                 if (attimer_sc != NULL) {
519                         set_i8254_freq(attimer_sc->mode, attimer_sc->period);
520                         attimer_sc->tc.tc_frequency = freq;
521                 } else {
522                         set_i8254_freq(0, 0);
523                 }
524         }
525         return (error);
526 }
527
528 SYSCTL_PROC(_machdep, OID_AUTO, i8254_freq, CTLTYPE_INT | CTLFLAG_RW,
529     0, sizeof(u_int), sysctl_machdep_i8254_freq, "IU",
530     "i8254 timer frequency");
531
532 static unsigned
533 i8254_get_timecount(struct timecounter *tc)
534 {
535         device_t dev = (device_t)tc->tc_priv;
536         struct attimer_softc *sc = device_get_softc(dev);
537         register_t flags;
538         uint16_t count;
539         u_int high, low;
540
541         if (sc->period == 0)
542                 return (i8254_max_count - getit());
543
544 #ifdef __amd64__
545         flags = read_rflags();
546 #else
547         flags = read_eflags();
548 #endif
549         mtx_lock_spin(&clock_lock);
550
551         /* Select timer0 and latch counter value. */
552         outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
553
554         low = inb(TIMER_CNTR0);
555         high = inb(TIMER_CNTR0);
556         count = i8254_max_count - ((high << 8) | low);
557         if (count < i8254_lastcount ||
558             (!i8254_ticked && (clkintr_pending ||
559             ((count < 20 || (!(flags & PSL_I) &&
560             count < i8254_max_count / 2u)) &&
561             i8254_pending != NULL && i8254_pending(i8254_intsrc))))) {
562                 i8254_ticked = 1;
563                 i8254_offset += i8254_max_count;
564         }
565         i8254_lastcount = count;
566         count += i8254_offset;
567         mtx_unlock_spin(&clock_lock);
568         return (count);
569 }
570
571 static int
572 attimer_start(struct eventtimer *et,
573     struct bintime *first, struct bintime *period)
574 {
575         device_t dev = (device_t)et->et_priv;
576         struct attimer_softc *sc = device_get_softc(dev);
577
578         if (period != NULL) {
579                 sc->mode = MODE_PERIODIC;
580                 sc->period = period->frac >> 32;
581         } else {
582                 sc->mode = MODE_ONESHOT;
583                 sc->period = first->frac >> 32;
584         }
585         if (!sc->intr_en) {
586                 i8254_intsrc->is_pic->pic_enable_source(i8254_intsrc);
587                 sc->intr_en = 1;
588         }
589         set_i8254_freq(sc->mode, sc->period);
590         return (0);
591 }
592
593 static int
594 attimer_stop(struct eventtimer *et)
595 {
596         device_t dev = (device_t)et->et_priv;
597         struct attimer_softc *sc = device_get_softc(dev);
598         
599         sc->mode = MODE_STOP;
600         sc->period = 0;
601         set_i8254_freq(sc->mode, sc->period);
602         return (0);
603 }
604
605 #ifdef DEV_ISA
606 /*
607  * Attach to the ISA PnP descriptors for the timer
608  */
609 static struct isa_pnp_id attimer_ids[] = {
610         { 0x0001d041 /* PNP0100 */, "AT timer" },
611         { 0 }
612 };
613
614 #ifdef PC98
615 static void
616 pc98_alloc_resource(device_t dev)
617 {
618         static bus_addr_t iat1[] = {0, 2, 4, 6};
619         static bus_addr_t iat2[] = {0, 4};
620         struct attimer_softc *sc;
621
622         sc = device_get_softc(dev);
623
624         sc->port_rid = 0;
625         bus_set_resource(dev, SYS_RES_IOPORT, sc->port_rid, IO_TIMER1, 1);
626         sc->port_res = isa_alloc_resourcev(dev, SYS_RES_IOPORT,
627             &sc->port_rid, iat1, 4, RF_ACTIVE);
628         if (sc->port_res == NULL)
629                 device_printf(dev, "Warning: Couldn't map I/O.\n");
630         else
631                 isa_load_resourcev(sc->port_res, iat1, 4);
632
633         sc->port_rid2 = 4;
634         bus_set_resource(dev, SYS_RES_IOPORT, sc->port_rid2, TIMER_CNTR1, 1);
635         sc->port_res2 = isa_alloc_resourcev(dev, SYS_RES_IOPORT,
636             &sc->port_rid2, iat2, 2, RF_ACTIVE);
637         if (sc->port_res2 == NULL)
638                 device_printf(dev, "Warning: Couldn't map I/O.\n");
639         else
640                 isa_load_resourcev(sc->port_res2, iat2, 2);
641 }
642
643 static void
644 pc98_release_resource(device_t dev)
645 {
646         struct attimer_softc *sc;
647
648         sc = device_get_softc(dev);
649
650         if (sc->port_res)
651                 bus_release_resource(dev, SYS_RES_IOPORT, sc->port_rid,
652                     sc->port_res);
653         if (sc->port_res2)
654                 bus_release_resource(dev, SYS_RES_IOPORT, sc->port_rid2,
655                     sc->port_res2);
656 }
657 #endif
658
659 static int
660 attimer_probe(device_t dev)
661 {
662         int result;
663         
664         result = ISA_PNP_PROBE(device_get_parent(dev), dev, attimer_ids);
665         /* ENOENT means no PnP-ID, device is hinted. */
666         if (result == ENOENT) {
667                 device_set_desc(dev, "AT timer");
668 #ifdef PC98
669                 /* To print resources correctly. */
670                 pc98_alloc_resource(dev);
671                 pc98_release_resource(dev);
672 #endif
673                 return (BUS_PROBE_LOW_PRIORITY);
674         }
675         return (result);
676 }
677
678 static int
679 attimer_attach(device_t dev)
680 {
681         struct attimer_softc *sc;
682         u_long s;
683         int i;
684
685         attimer_sc = sc = device_get_softc(dev);
686         bzero(sc, sizeof(struct attimer_softc));
687 #ifdef PC98
688         pc98_alloc_resource(dev);
689 #else
690         if (!(sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT,
691             &sc->port_rid, IO_TIMER1, IO_TIMER1 + 3, 4, RF_ACTIVE)))
692                 device_printf(dev,"Warning: Couldn't map I/O.\n");
693 #endif
694         i8254_intsrc = intr_lookup_source(0);
695         if (i8254_intsrc != NULL)
696                 i8254_pending = i8254_intsrc->is_pic->pic_source_pending;
697         resource_int_value(device_get_name(dev), device_get_unit(dev),
698             "timecounter", &i8254_timecounter);
699         set_i8254_freq(0, 0);
700         if (i8254_timecounter) {
701                 sc->tc.tc_get_timecount = i8254_get_timecount;
702                 sc->tc.tc_counter_mask = 0xffff;
703                 sc->tc.tc_frequency = i8254_freq;
704                 sc->tc.tc_name = "i8254";
705                 sc->tc.tc_quality = 0;
706                 sc->tc.tc_priv = dev;
707                 tc_init(&sc->tc);
708         }
709         if (resource_int_value(device_get_name(dev), device_get_unit(dev),
710             "clock", &i) != 0 || i != 0) {
711                 sc->intr_rid = 0;
712                 while (bus_get_resource(dev, SYS_RES_IRQ, sc->intr_rid,
713                     &s, NULL) == 0 && s != 0)
714                         sc->intr_rid++;
715                 if (!(sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
716                     &sc->intr_rid, 0, 0, 1, RF_ACTIVE))) {
717                         device_printf(dev,"Can't map interrupt.\n");
718                         return (0);
719                 }
720                 /* Dirty hack, to make bus_setup_intr to not enable source. */
721                 i8254_intsrc->is_handlers++;
722                 if ((bus_setup_intr(dev, sc->intr_res,
723                     INTR_MPSAFE | INTR_TYPE_CLK,
724                     (driver_filter_t *)clkintr, NULL,
725                     sc, &sc->intr_handler))) {
726                         device_printf(dev, "Can't setup interrupt.\n");
727                         i8254_intsrc->is_handlers--;
728                         return (0);
729                 }
730                 i8254_intsrc->is_handlers--;
731                 i8254_intsrc->is_pic->pic_enable_intr(i8254_intsrc);
732                 sc->et.et_name = "i8254";
733                 sc->et.et_flags = ET_FLAGS_PERIODIC;
734                 if (!i8254_timecounter)
735                         sc->et.et_flags |= ET_FLAGS_ONESHOT;
736                 sc->et.et_quality = 100;
737                 sc->et.et_frequency = i8254_freq;
738                 sc->et.et_min_period.sec = 0;
739                 sc->et.et_min_period.frac =
740                     ((0x0002LLU << 48) / i8254_freq) << 16;
741                 sc->et.et_max_period.sec = 0xffff / i8254_freq;
742                 sc->et.et_max_period.frac =
743                     ((0xfffeLLU << 48) / i8254_freq) << 16;
744                 sc->et.et_start = attimer_start;
745                 sc->et.et_stop = attimer_stop;
746                 sc->et.et_priv = dev;
747                 et_register(&sc->et);
748         }
749         return(0);
750 }
751
752 static int
753 attimer_resume(device_t dev)
754 {
755
756         i8254_restore();
757         return (0);
758 }
759
760 static device_method_t attimer_methods[] = {
761         /* Device interface */
762         DEVMETHOD(device_probe,         attimer_probe),
763         DEVMETHOD(device_attach,        attimer_attach),
764         DEVMETHOD(device_detach,        bus_generic_detach),
765         DEVMETHOD(device_shutdown,      bus_generic_shutdown),
766         DEVMETHOD(device_suspend,       bus_generic_suspend),
767         DEVMETHOD(device_resume,        attimer_resume),
768         { 0, 0 }
769 };
770
771 static driver_t attimer_driver = {
772         "attimer",
773         attimer_methods,
774         sizeof(struct attimer_softc),
775 };
776
777 static devclass_t attimer_devclass;
778
779 DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0);
780 DRIVER_MODULE(attimer, acpi, attimer_driver, attimer_devclass, 0, 0);
781
782 #endif /* DEV_ISA */