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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 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 */