aboutsummaryrefslogtreecommitdiff
path: root/drivers/char/hpet.c
blob: 9ded667625ac06c91d1940bf79ba261b65943b59 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
/*
 * Intel & MS High Precision Event Timer Implementation.
 *
 * Copyright (C) 2003 Intel Corporation
 *	Venki Pallipadi
 * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
 *	Bob Picco <robert.picco@hp.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/smp_lock.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/major.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/sysctl.h>
#include <linux/wait.h>
#include <linux/bcd.h>
#include <linux/seq_file.h>
#include <linux/bitops.h>
#include <linux/clocksource.h>
#include <linux/slab.h>

#include <asm/current.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/div64.h>

#include <linux/acpi.h>
#include <acpi/acpi_bus.h>
#include <linux/hpet.h>

/*
 * The High Precision Event Timer driver.
 * This driver is closely modelled after the rtc.c driver.
 * http://www.intel.com/hardwaredesign/hpetspec_1.pdf
 */
#define	HPET_USER_FREQ	(64)
#define	HPET_DRIFT	(500)

#define HPET_RANGE_SIZE		1024	/* from HPET spec */


/* WARNING -- don't get confused.  These macros are never used
 * to write the (single) counter, and rarely to read it.
 * They're badly named; to fix, someday.
 */
#if BITS_PER_LONG == 64
#define	write_counter(V, MC)	writeq(V, MC)
#define	read_counter(MC)	readq(MC)
#else
#define	write_counter(V, MC)	writel(V, MC)
#define	read_counter(MC)	readl(MC)
#endif

static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;

/* This clocksource driver currently only works on ia64 */
#ifdef CONFIG_IA64
static void __iomem *hpet_mctr;

static cycle_t read_hpet(struct clocksource *cs)
{
	return (cycle_t)read_counter((void __iomem *)hpet_mctr);
}

static struct clocksource clocksource_hpet = {
        .name           = "hpet",
        .rating         = 250,
        .read           = read_hpet,
        .mask           = CLOCKSOURCE_MASK(64),
	.mult		= 0, /* to be calculated */
        .shift          = 10,
        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
};
static struct clocksource *hpet_clocksource;
#endif

/* A lock for concurrent access by app and isr hpet activity. */
static DEFINE_SPINLOCK(hpet_lock);

#define	HPET_DEV_NAME	(7)

struct hpet_dev {
	struct hpets *hd_hpets;
	struct hpet __iomem *hd_hpet;
	struct hpet_timer __iomem *hd_timer;
	unsigned long hd_ireqfreq;
	unsigned long hd_irqdata;
	wait_queue_head_t hd_waitqueue;
	struct fasync_struct *hd_async_queue;
	unsigned int hd_flags;
	unsigned int hd_irq;
	unsigned int hd_hdwirq;
	char hd_name[HPET_DEV_NAME];
};

struct hpets {
	struct hpets *hp_next;
	struct hpet __iomem *hp_hpet;
	unsigned long hp_hpet_phys;
	struct clocksource *hp_clocksource;
	unsigned long long hp_tick_freq;
	unsigned long hp_delta;
	unsigned int hp_ntimer;
	unsigned int hp_which;
	struct hpet_dev hp_dev[1];
};

static struct hpets *hpets;

#define	HPET_OPEN		0x0001
#define	HPET_IE			0x0002	/* interrupt enabled */
#define	HPET_PERIODIC		0x0004
#define	HPET_SHARED_IRQ		0x0008


#ifndef readq
static inline unsigned long long readq(void __iomem *addr)
{
	return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
}
#endif

#ifndef writeq
static inline void writeq(unsigned long long v, void __iomem *addr)
{
	writel(v & 0xffffffff, addr);
	writel(v >> 32, addr + 4);
}
#endif

static irqreturn_t hpet_interrupt(int irq, void *data)
{
	struct hpet_dev *devp;
	unsigned long isr;

	devp = data;
	isr = 1 << (devp - devp->hd_hpets->hp_dev);

	if ((devp->hd_flags & HPET_SHARED_IRQ) &&
	    !(isr & readl(&devp->hd_hpet->hpet_isr)))
		return IRQ_NONE;

	spin_lock(&hpet_lock);
	devp->hd_irqdata++;

	/*
	 * For non-periodic timers, increment the accumulator.
	 * This has the effect of treating non-periodic like periodic.
	 */
	if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
		unsigned long m, t;

		t = devp->hd_ireqfreq;
		m = read_counter(&devp->hd_timer->hpet_compare);
		write_counter(t + m, &devp->hd_timer->hpet_compare);
	}

	if (devp->hd_flags & HPET_SHARED_IRQ)
		writel(isr, &devp->hd_hpet->hpet_isr);
	spin_unlock(&hpet_lock);

	wake_up_interruptible(&devp->hd_waitqueue);

	kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);

	return IRQ_HANDLED;
}

static void hpet_timer_set_irq(struct hpet_dev *devp)
{
	unsigned long v;
	int irq, gsi;
	struct hpet_timer __iomem *timer;

	spin_lock_irq(&hpet_lock);
	if (devp->hd_hdwirq) {
		spin_unlock_irq(&hpet_lock);
		return;
	}

	timer = devp->hd_timer;

	/* we prefer level triggered mode */
	v = readl(&timer->hpet_config);
	if (!(v & Tn_INT_TYPE_CNF_MASK)) {
		v |= Tn_INT_TYPE_CNF_MASK;
		writel(v, &timer->hpet_config);
	}
	spin_unlock_irq(&hpet_lock);

	v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
				 Tn_INT_ROUTE_CAP_SHIFT;

	/*
	 * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
	 * legacy device. In IO APIC mode, we skip all the legacy IRQS.
	 */
	if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
		v &= ~0xf3df;
	else
		v &= ~0xffff;

	for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
		if (irq >= nr_irqs) {
			irq = HPET_MAX_IRQ;
			break;
		}

		gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
					ACPI_ACTIVE_LOW);
		if (gsi > 0)
			break;

		/* FIXME: Setup interrupt source table */
	}

	if (irq < HPET_MAX_IRQ) {
		spin_lock_irq(&hpet_lock);
		v = readl(&timer->hpet_config);
		v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
		writel(v, &timer->hpet_config);
		devp->hd_hdwirq = gsi;
		spin_unlock_irq(&hpet_lock);
	}
	return;
}

static int hpet_open(struct inode *inode, struct file *file)
{
	struct hpet_dev *devp;
	struct hpets *hpetp;
	int i;

	if (file->f_mode & FMODE_WRITE)
		return -EINVAL;

	lock_kernel();
	spin_lock_irq(&hpet_lock);

	for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
		for (i = 0; i < hpetp->hp_ntimer; i++)
			if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
				continue;
			else {
				devp = &hpetp->hp_dev[i];
				break;
			}

	if (!devp) {
		spin_unlock_irq(&hpet_lock);
		unlock_kernel();
		return -EBUSY;
	}

	file->private_data = devp;
	devp->hd_irqdata = 0;
	devp->hd_flags |= HPET_OPEN;
	spin_unlock_irq(&hpet_lock);
	unlock_kernel();

	hpet_timer_set_irq(devp);

	return 0;
}

static ssize_t
hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
{
	DECLARE_WAITQUEUE(wait, current);
	unsigned long data;
	ssize_t retval;
	struct hpet_dev *devp;

	devp = file->private_data;
	if (!devp->hd_ireqfreq)
		return -EIO;

	if (count < sizeof(unsigned long))
		return -EINVAL;

	add_wait_queue(&devp->hd_waitqueue, &wait);

	for ( ; ; ) {
		set_current_state(TASK_INTERRUPTIBLE);

		spin_lock_irq(&hpet_lock);
		data = devp->hd_irqdata;
		devp->hd_irqdata = 0;
		spin_unlock_irq(&hpet_lock);

		if (data)
			break;
		else if (file->f_flags & O_NONBLOCK) {
			retval = -EAGAIN;
			goto out;
		} else if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			goto out;
		}
		schedule();
	}

	retval = put_user(data, (unsigned long __user *)buf);
	if (!retval)
		retval = sizeof(unsigned long);
out:
	__set_current_state(TASK_RUNNING);
	remove_wait_queue(&devp->hd_waitqueue, &wait);

	return retval;
}

static unsigned int hpet_poll(struct file *file, poll_table * wait)
{
	unsigned long v;
	struct hpet_dev *devp;

	devp = file->private_data;

	if (!devp->hd_ireqfreq)
		return 0;

	poll_wait(file, &devp->hd_waitqueue, wait);

	spin_lock_irq(&hpet_lock);
	v = devp->hd_irqdata;
	spin_unlock_irq(&hpet_lock);

	if (v != 0)
		return POLLIN | POLLRDNORM;

	return 0;
}

static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
{
#ifdef	CONFIG_HPET_MMAP
	struct hpet_dev *devp;
	unsigned long addr;

	if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
		return -EINVAL;

	devp = file->private_data;
	addr = devp->hd_hpets->hp_hpet_phys;

	if (addr & (PAGE_SIZE - 1))
		return -ENOSYS;

	vma->vm_flags |= VM_IO;
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
					PAGE_SIZE, vma->vm_page_prot)) {
		printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
			__func__);
		return -EAGAIN;
	}

	return 0;
#else
	return -ENOSYS;
#endif
}

static int hpet_fasync(int fd, struct file *file, int on)
{
	struct hpet_dev *devp;

	devp = file->private_data;

	if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
		return 0;
	else
		return -EIO;
}

static int hpet_release(struct inode *inode, struct file *file)
{
	struct hpet_dev *devp;
	struct hpet_timer __iomem *timer;
	int irq = 0;

	devp = file->private_data;
	timer = devp->hd_timer;

	spin_lock_irq(&hpet_lock);

	writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
	       &timer->hpet_config);

	irq = devp->hd_irq;
	devp->hd_irq = 0;

	devp->hd_ireqfreq = 0;

	if (devp->hd_flags & HPET_PERIODIC
	    && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
		unsigned long v;

		v = readq(&timer->hpet_config);
		v ^= Tn_TYPE_CNF_MASK;
		writeq(v, &timer->hpet_config);
	}

	devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
	spin_unlock_irq(&hpet_lock);

	if (irq)
		free_irq(irq, devp);

	file->private_data = NULL;
	return 0;
}

static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);

static int
hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
	   unsigned long arg)
{
	struct hpet_dev *devp;

	devp = file->private_data;
	return hpet_ioctl_common(devp, cmd, arg, 0);
}

static int hpet_ioctl_ieon(struct hpet_dev *devp)
{
	struct hpet_timer __iomem *timer;
	struct hpet __iomem *hpet;
	struct hpets *hpetp;
	int irq;
	unsigned long g, v, t, m;
	unsigned long flags, isr;

	timer = devp->hd_timer;
	hpet = devp->hd_hpet;
	hpetp = devp->hd_hpets;

	if (!devp->hd_ireqfreq)
		return -EIO;

	spin_lock_irq(&hpet_lock);

	if (devp->hd_flags & HPET_IE) {
		spin_unlock_irq(&hpet_lock);
		return -EBUSY;
	}

	devp->hd_flags |= HPET_IE;

	if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
		devp->hd_flags |= HPET_SHARED_IRQ;
	spin_unlock_irq(&hpet_lock);

	irq = devp->hd_hdwirq;

	if (irq) {
		unsigned long irq_flags;

		sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
		irq_flags = devp->hd_flags & HPET_SHARED_IRQ
						? IRQF_SHARED : IRQF_DISABLED;
		if (request_irq(irq, hpet_interrupt, irq_flags,
				devp->hd_name, (void *)devp)) {
			printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
			irq = 0;
		}
	}

	if (irq == 0) {
		spin_lock_irq(&hpet_lock);
		devp->hd_flags ^= HPET_IE;
		spin_unlock_irq(&hpet_lock);
		return -EIO;
	}

	devp->hd_irq = irq;
	t = devp->hd_ireqfreq;
	v = readq(&timer->hpet_config);

	/* 64-bit comparators are not yet supported through the ioctls,
	 * so force this into 32-bit mode if it supports both modes
	 */
	g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;

	if (devp->hd_flags & HPET_PERIODIC) {
		g |= Tn_TYPE_CNF_MASK;
		v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
		writeq(v, &timer->hpet_config);
		local_irq_save(flags);

		/*
		 * NOTE: First we modify the hidden accumulator
		 * register supported by periodic-capable comparators.
		 * We never want to modify the (single) counter; that
		 * would affect all the comparators. The value written
		 * is the counter value when the first interrupt is due.
		 */
		m = read_counter(&hpet->hpet_mc);
		write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
		/*
		 * Then we modify the comparator, indicating the period
		 * for subsequent interrupt.
		 */
		write_counter(t, &timer->hpet_compare);
	} else {
		local_irq_save(flags);
		m = read_counter(&hpet->hpet_mc);
		write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
	}

	if (devp->hd_flags & HPET_SHARED_IRQ) {
		isr = 1 << (devp - devp->hd_hpets->hp_dev);
		writel(isr, &hpet->hpet_isr);
	}
	writeq(g, &timer->hpet_config);
	local_irq_restore(flags);

	return 0;
}

/* converts Hz to number of timer ticks */
static inline unsigned long hpet_time_div(struct hpets *hpets,
					  unsigned long dis)
{
	unsigned long long m;

	m = hpets->hp_tick_freq + (dis >> 1);
	do_div(m, dis);
	return (unsigned long)m;
}

static int
hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
{
	struct hpet_timer __iomem *timer;
	struct hpet __iomem *hpet;
	struct hpets *hpetp;
	int err;
	unsigned long v;

	switch (cmd) {
	case HPET_IE_OFF:
	case HPET_INFO:
	case HPET_EPI:
	case HPET_DPI:
	case HPET_IRQFREQ:
		timer = devp->hd_timer;
		hpet = devp->hd_hpet;
		hpetp = devp->hd_hpets;
		break;
	case HPET_IE_ON:
		return hpet_ioctl_ieon(devp);
	default:
		return -EINVAL;
	}

	err = 0;

	switch (cmd) {
	case HPET_IE_OFF:
		if ((devp->hd_flags & HPET_IE) == 0)
			break;
		v = readq(&timer->hpet_config);
		v &= ~Tn_INT_ENB_CNF_MASK;
		writeq(v, &timer->hpet_config);
		if (devp->hd_irq) {
			free_irq(devp->hd_irq, devp);
			devp->hd_irq = 0;
		}
		devp->hd_flags ^= HPET_IE;
		break;
	case HPET_INFO:
		{
			struct hpet_info info;

			if (devp->hd_ireqfreq)
				info.hi_ireqfreq =
					hpet_time_div(hpetp, devp->hd_ireqfreq);
			else
				info.hi_ireqfreq = 0;
			info.hi_flags =
			    readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
			info.hi_hpet = hpetp->hp_which;
			info.hi_timer = devp - hpetp->hp_dev;
			if (kernel)
				memcpy((void *)arg, &info, sizeof(info));
			else
				if (copy_to_user((void __user *)arg, &info,
						 sizeof(info)))
					err = -EFAULT;
			break;
		}
	case HPET_EPI:
		v = readq(&timer->hpet_config);
		if ((v & Tn_PER_INT_CAP_MASK) == 0) {
			err = -ENXIO;
			break;
		}
		devp->hd_flags |= HPET_PERIODIC;
		break;
	case HPET_DPI:
		v = readq(&timer->hpet_config);
		if ((v & Tn_PER_INT_CAP_MASK) == 0) {
			err = -ENXIO;
			break;
		}
		if (devp->hd_flags & HPET_PERIODIC &&
		    readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
			v = readq(&timer->hpet_config);
			v ^= Tn_TYPE_CNF_MASK;
			writeq(v, &timer->hpet_config);
		}
		devp->hd_flags &= ~HPET_PERIODIC;
		break;
	case HPET_IRQFREQ:
		if (!kernel && (arg > hpet_max_freq) &&
		    !capable(CAP_SYS_RESOURCE)) {
			err = -EACCES;
			break;
		}

		if (!arg) {
			err = -EINVAL;
			break;
		}

		devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
	}

	return err;
}

static const struct file_operations hpet_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.read = hpet_read,
	.poll = hpet_poll,
	.ioctl = hpet_ioctl,
	.open = hpet_open,
	.release = hpet_release,
	.fasync = hpet_fasync,
	.mmap = hpet_mmap,
};

static int hpet_is_known(struct hpet_data *hdp)
{
	struct hpets *hpetp;

	for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
		if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
			return 1;

	return 0;
}

static ctl_table hpet_table[] = {
	{
	 .procname = "max-user-freq",
	 .data = &hpet_max_freq,
	 .maxlen = sizeof(int),
	 .mode = 0644,
	 .proc_handler = proc_dointvec,
	 },
	{}
};

static ctl_table hpet_root[] = {
	{
	 .procname = "hpet",
	 .maxlen = 0,
	 .mode = 0555,
	 .child = hpet_table,
	 },
	{}
};

static ctl_table dev_root[] = {
	{
	 .procname = "dev",
	 .maxlen = 0,
	 .mode = 0555,
	 .child = hpet_root,
	 },
	{}
};

static struct ctl_table_header *sysctl_header;

/*
 * Adjustment for when arming the timer with
 * initial conditions.  That is, main counter
 * ticks expired before interrupts are enabled.
 */
#define	TICK_CALIBRATE	(1000UL)

static unsigned long __hpet_calibrate(struct hpets *hpetp)
{
	struct hpet_timer __iomem *timer = NULL;
	unsigned long t, m, count, i, flags, start;
	struct hpet_dev *devp;
	int j;
	struct hpet __iomem *hpet;

	for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
		if ((devp->hd_flags & HPET_OPEN) == 0) {
			timer = devp->hd_timer;
			break;
		}

	if (!timer)
		return 0;

	hpet = hpetp->hp_hpet;
	t = read_counter(&timer->hpet_compare);

	i = 0;
	count = hpet_time_div(hpetp, TICK_CALIBRATE);

	local_irq_save(flags);

	start = read_counter(&hpet->hpet_mc);

	do {
		m = read_counter(&hpet->hpet_mc);
		write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
	} while (i++, (m - start) < count);

	local_irq_restore(flags);

	return (m - start) / i;
}

static unsigned long hpet_calibrate(struct hpets *hpetp)
{
	unsigned long ret = -1;
	unsigned long tmp;

	/*
	 * Try to calibrate until return value becomes stable small value.
	 * If SMI interruption occurs in calibration loop, the return value
	 * will be big. This avoids its impact.
	 */
	for ( ; ; ) {
		tmp = __hpet_calibrate(hpetp);
		if (ret <= tmp)
			break;
		ret = tmp;
	}

	return ret;
}

int hpet_alloc(struct hpet_data *hdp)
{
	u64 cap, mcfg;
	struct hpet_dev *devp;
	u32 i, ntimer;
	struct hpets *hpetp;
	size_t siz;
	struct hpet __iomem *hpet;
	static struct hpets *last = NULL;
	unsigned long period;
	unsigned long long temp;
	u32 remainder;

	/*
	 * hpet_alloc can be called by platform dependent code.
	 * If platform dependent code has allocated the hpet that
	 * ACPI has also reported, then we catch it here.
	 */
	if (hpet_is_known(hdp)) {
		printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
			__func__);
		return 0;
	}

	siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
				      sizeof(struct hpet_dev));

	hpetp = kzalloc(siz, GFP_KERNEL);

	if (!hpetp)
		return -ENOMEM;

	hpetp->hp_which = hpet_nhpet++;
	hpetp->hp_hpet = hdp->hd_address;
	hpetp->hp_hpet_phys = hdp->hd_phys_address;

	hpetp->hp_ntimer = hdp->hd_nirqs;

	for (i = 0; i < hdp->hd_nirqs; i++)
		hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];

	hpet = hpetp->hp_hpet;

	cap = readq(&hpet->hpet_cap);

	ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;

	if (hpetp->hp_ntimer != ntimer) {
		printk(KERN_WARNING "hpet: number irqs doesn't agree"
		       " with number of timers\n");
		kfree(hpetp);
		return -ENODEV;
	}

	if (last)
		last->hp_next = hpetp;
	else
		hpets = hpetp;

	last = hpetp;

	period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
		HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
	temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
	temp += period >> 1; /* round */
	do_div(temp, period);
	hpetp->hp_tick_freq = temp; /* ticks per second */

	printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
		hpetp->hp_which, hdp->hd_phys_address,
		hpetp->hp_ntimer > 1 ? "s" : "");
	for (i = 0; i < hpetp->hp_ntimer; i++)
		printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
	printk("\n");

	temp = hpetp->hp_tick_freq;
	remainder = do_div(temp, 1000000);
	printk(KERN_INFO
		"hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
		hpetp->hp_which, hpetp->hp_ntimer,
		cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
		(unsigned) temp, remainder);

	mcfg = readq(&hpet->hpet_config);
	if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
		write_counter(0L, &hpet->hpet_mc);
		mcfg |= HPET_ENABLE_CNF_MASK;
		writeq(mcfg, &hpet->hpet_config);
	}

	for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
		struct hpet_timer __iomem *timer;

		timer = &hpet->hpet_timers[devp - hpetp->hp_dev];

		devp->hd_hpets = hpetp;
		devp->hd_hpet = hpet;
		devp->hd_timer = timer;

		/*
		 * If the timer was reserved by platform code,
		 * then make timer unavailable for opens.
		 */
		if (hdp->hd_state & (1 << i)) {
			devp->hd_flags = HPET_OPEN;
			continue;
		}

		init_waitqueue_head(&devp->hd_waitqueue);
	}

	hpetp->hp_delta = hpet_calibrate(hpetp);

/* This clocksource driver currently only works on ia64 */
#ifdef CONFIG_IA64
	if (!hpet_clocksource) {
		hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
		CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
		clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
						clocksource_hpet.shift);
		clocksource_register(&clocksource_hpet);
		hpetp->hp_clocksource = &clocksource_hpet;
		hpet_clocksource = &clocksource_hpet;
	}
#endif

	return 0;
}

static acpi_status hpet_resources(struct acpi_resource *res, void *data)
{
	struct hpet_data *hdp;
	acpi_status status;
	struct acpi_resource_address64 addr;

	hdp = data;

	status = acpi_resource_to_address64(res, &addr);

	if (ACPI_SUCCESS(status)) {
		hdp->hd_phys_address = addr.minimum;
		hdp->hd_address = ioremap(addr.minimum, addr.address_length);

		if (hpet_is_known(hdp)) {
			iounmap(hdp->hd_address);
			return AE_ALREADY_EXISTS;
		}
	} else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
		struct acpi_resource_fixed_memory32 *fixmem32;

		fixmem32 = &res->data.fixed_memory32;
		if (!fixmem32)
			return AE_NO_MEMORY;

		hdp->hd_phys_address = fixmem32->address;
		hdp->hd_address = ioremap(fixmem32->address,
						HPET_RANGE_SIZE);

		if (hpet_is_known(hdp)) {
			iounmap(hdp->hd_address);
			return AE_ALREADY_EXISTS;
		}
	} else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
		struct acpi_resource_extended_irq *irqp;
		int i, irq;

		irqp = &res->data.extended_irq;

		for (i = 0; i < irqp->interrupt_count; i++) {
			irq = acpi_register_gsi(NULL, irqp->interrupts[i],
				      irqp->triggering, irqp->polarity);
			if (irq < 0)
				return AE_ERROR;

			hdp->hd_irq[hdp->hd_nirqs] = irq;
			hdp->hd_nirqs++;
		}
	}

	return AE_OK;
}

static int hpet_acpi_add(struct acpi_device *device)
{
	acpi_status result;
	struct hpet_data data;

	memset(&data, 0, sizeof(data));

	result =
	    acpi_walk_resources(device->handle, METHOD_NAME__CRS,
				hpet_resources, &data);

	if (ACPI_FAILURE(result))
		return -ENODEV;

	if (!data.hd_address || !data.hd_nirqs) {
		printk("%s: no address or irqs in _CRS\n", __func__);
		return -ENODEV;
	}

	return hpet_alloc(&data);
}

static int hpet_acpi_remove(struct acpi_device *device, int type)
{
	/* XXX need to unregister clocksource, dealloc mem, etc */
	return -EINVAL;
}

static const struct acpi_device_id hpet_device_ids[] = {
	{"PNP0103", 0},
	{"", 0},
};
MODULE_DEVICE_TABLE(acpi, hpet_device_ids);

static struct acpi_driver hpet_acpi_driver = {
	.name = "hpet",
	.ids = hpet_device_ids,
	.ops = {
		.add = hpet_acpi_add,
		.remove = hpet_acpi_remove,
		},
};

static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };

static int __init hpet_init(void)
{
	int result;

	result = misc_register(&hpet_misc);
	if (result < 0)
		return -ENODEV;

	sysctl_header = register_sysctl_table(dev_root);

	result = acpi_bus_register_driver(&hpet_acpi_driver);
	if (result < 0) {
		if (sysctl_header)
			unregister_sysctl_table(sysctl_header);
		misc_deregister(&hpet_misc);
		return result;
	}

	return 0;
}

static void __exit hpet_exit(void)
{
	acpi_bus_unregister_driver(&hpet_acpi_driver);

	if (sysctl_header)
		unregister_sysctl_table(sysctl_header);
	misc_deregister(&hpet_misc);

	return;
}

module_init(hpet_init);
module_exit(hpet_exit);
MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
MODULE_LICENSE("GPL");