GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / char / hpet.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Intel & MS High Precision Event Timer Implementation.
4  *
5  * Copyright (C) 2003 Intel Corporation
6  *      Venki Pallipadi
7  * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
8  *      Bob Picco <robert.picco@hp.com>
9  */
10
11 #include <linux/interrupt.h>
12 #include <linux/kernel.h>
13 #include <linux/types.h>
14 #include <linux/miscdevice.h>
15 #include <linux/major.h>
16 #include <linux/ioport.h>
17 #include <linux/fcntl.h>
18 #include <linux/init.h>
19 #include <linux/io-64-nonatomic-lo-hi.h>
20 #include <linux/poll.h>
21 #include <linux/mm.h>
22 #include <linux/proc_fs.h>
23 #include <linux/spinlock.h>
24 #include <linux/sysctl.h>
25 #include <linux/wait.h>
26 #include <linux/sched/signal.h>
27 #include <linux/bcd.h>
28 #include <linux/seq_file.h>
29 #include <linux/bitops.h>
30 #include <linux/compat.h>
31 #include <linux/clocksource.h>
32 #include <linux/uaccess.h>
33 #include <linux/slab.h>
34 #include <linux/io.h>
35 #include <linux/acpi.h>
36 #include <linux/hpet.h>
37 #include <asm/current.h>
38 #include <asm/irq.h>
39 #include <asm/div64.h>
40
41 /*
42  * The High Precision Event Timer driver.
43  * This driver is closely modelled after the rtc.c driver.
44  * See HPET spec revision 1.
45  */
46 #define HPET_USER_FREQ  (64)
47 #define HPET_DRIFT      (500)
48
49 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
50
51
52 /* WARNING -- don't get confused.  These macros are never used
53  * to write the (single) counter, and rarely to read it.
54  * They're badly named; to fix, someday.
55  */
56 #if BITS_PER_LONG == 64
57 #define write_counter(V, MC)    writeq(V, MC)
58 #define read_counter(MC)        readq(MC)
59 #else
60 #define write_counter(V, MC)    writel(V, MC)
61 #define read_counter(MC)        readl(MC)
62 #endif
63
64 static DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
65 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
66
67 /* This clocksource driver currently only works on ia64 */
68 #ifdef CONFIG_IA64
69 static void __iomem *hpet_mctr;
70
71 static u64 read_hpet(struct clocksource *cs)
72 {
73         return (u64)read_counter((void __iomem *)hpet_mctr);
74 }
75
76 static struct clocksource clocksource_hpet = {
77         .name           = "hpet",
78         .rating         = 250,
79         .read           = read_hpet,
80         .mask           = CLOCKSOURCE_MASK(64),
81         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
82 };
83 static struct clocksource *hpet_clocksource;
84 #endif
85
86 /* A lock for concurrent access by app and isr hpet activity. */
87 static DEFINE_SPINLOCK(hpet_lock);
88
89 #define HPET_DEV_NAME   (7)
90
91 struct hpet_dev {
92         struct hpets *hd_hpets;
93         struct hpet __iomem *hd_hpet;
94         struct hpet_timer __iomem *hd_timer;
95         unsigned long hd_ireqfreq;
96         unsigned long hd_irqdata;
97         wait_queue_head_t hd_waitqueue;
98         struct fasync_struct *hd_async_queue;
99         unsigned int hd_flags;
100         unsigned int hd_irq;
101         unsigned int hd_hdwirq;
102         char hd_name[HPET_DEV_NAME];
103 };
104
105 struct hpets {
106         struct hpets *hp_next;
107         struct hpet __iomem *hp_hpet;
108         unsigned long hp_hpet_phys;
109         struct clocksource *hp_clocksource;
110         unsigned long long hp_tick_freq;
111         unsigned long hp_delta;
112         unsigned int hp_ntimer;
113         unsigned int hp_which;
114         struct hpet_dev hp_dev[];
115 };
116
117 static struct hpets *hpets;
118
119 #define HPET_OPEN               0x0001
120 #define HPET_IE                 0x0002  /* interrupt enabled */
121 #define HPET_PERIODIC           0x0004
122 #define HPET_SHARED_IRQ         0x0008
123
124 static irqreturn_t hpet_interrupt(int irq, void *data)
125 {
126         struct hpet_dev *devp;
127         unsigned long isr;
128
129         devp = data;
130         isr = 1 << (devp - devp->hd_hpets->hp_dev);
131
132         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
133             !(isr & readl(&devp->hd_hpet->hpet_isr)))
134                 return IRQ_NONE;
135
136         spin_lock(&hpet_lock);
137         devp->hd_irqdata++;
138
139         /*
140          * For non-periodic timers, increment the accumulator.
141          * This has the effect of treating non-periodic like periodic.
142          */
143         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
144                 unsigned long t, mc, base, k;
145                 struct hpet __iomem *hpet = devp->hd_hpet;
146                 struct hpets *hpetp = devp->hd_hpets;
147
148                 t = devp->hd_ireqfreq;
149                 read_counter(&devp->hd_timer->hpet_compare);
150                 mc = read_counter(&hpet->hpet_mc);
151                 /* The time for the next interrupt would logically be t + m,
152                  * however, if we are very unlucky and the interrupt is delayed
153                  * for longer than t then we will completely miss the next
154                  * interrupt if we set t + m and an application will hang.
155                  * Therefore we need to make a more complex computation assuming
156                  * that there exists a k for which the following is true:
157                  * k * t + base < mc + delta
158                  * (k + 1) * t + base > mc + delta
159                  * where t is the interval in hpet ticks for the given freq,
160                  * base is the theoretical start value 0 < base < t,
161                  * mc is the main counter value at the time of the interrupt,
162                  * delta is the time it takes to write the a value to the
163                  * comparator.
164                  * k may then be computed as (mc - base + delta) / t .
165                  */
166                 base = mc % t;
167                 k = (mc - base + hpetp->hp_delta) / t;
168                 write_counter(t * (k + 1) + base,
169                               &devp->hd_timer->hpet_compare);
170         }
171
172         if (devp->hd_flags & HPET_SHARED_IRQ)
173                 writel(isr, &devp->hd_hpet->hpet_isr);
174         spin_unlock(&hpet_lock);
175
176         wake_up_interruptible(&devp->hd_waitqueue);
177
178         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
179
180         return IRQ_HANDLED;
181 }
182
183 static void hpet_timer_set_irq(struct hpet_dev *devp)
184 {
185         unsigned long v;
186         int irq, gsi;
187         struct hpet_timer __iomem *timer;
188
189         spin_lock_irq(&hpet_lock);
190         if (devp->hd_hdwirq) {
191                 spin_unlock_irq(&hpet_lock);
192                 return;
193         }
194
195         timer = devp->hd_timer;
196
197         /* we prefer level triggered mode */
198         v = readl(&timer->hpet_config);
199         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
200                 v |= Tn_INT_TYPE_CNF_MASK;
201                 writel(v, &timer->hpet_config);
202         }
203         spin_unlock_irq(&hpet_lock);
204
205         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
206                                  Tn_INT_ROUTE_CAP_SHIFT;
207
208         /*
209          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
210          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
211          */
212         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
213                 v &= ~0xf3df;
214         else
215                 v &= ~0xffff;
216
217         for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
218                 if (irq >= nr_irqs) {
219                         irq = HPET_MAX_IRQ;
220                         break;
221                 }
222
223                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
224                                         ACPI_ACTIVE_LOW);
225                 if (gsi > 0)
226                         break;
227
228                 /* FIXME: Setup interrupt source table */
229         }
230
231         if (irq < HPET_MAX_IRQ) {
232                 spin_lock_irq(&hpet_lock);
233                 v = readl(&timer->hpet_config);
234                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
235                 writel(v, &timer->hpet_config);
236                 devp->hd_hdwirq = gsi;
237                 spin_unlock_irq(&hpet_lock);
238         }
239         return;
240 }
241
242 static int hpet_open(struct inode *inode, struct file *file)
243 {
244         struct hpet_dev *devp;
245         struct hpets *hpetp;
246         int i;
247
248         if (file->f_mode & FMODE_WRITE)
249                 return -EINVAL;
250
251         mutex_lock(&hpet_mutex);
252         spin_lock_irq(&hpet_lock);
253
254         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
255                 for (i = 0; i < hpetp->hp_ntimer; i++)
256                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN) {
257                                 continue;
258                         } else {
259                                 devp = &hpetp->hp_dev[i];
260                                 break;
261                         }
262
263         if (!devp) {
264                 spin_unlock_irq(&hpet_lock);
265                 mutex_unlock(&hpet_mutex);
266                 return -EBUSY;
267         }
268
269         file->private_data = devp;
270         devp->hd_irqdata = 0;
271         devp->hd_flags |= HPET_OPEN;
272         spin_unlock_irq(&hpet_lock);
273         mutex_unlock(&hpet_mutex);
274
275         hpet_timer_set_irq(devp);
276
277         return 0;
278 }
279
280 static ssize_t
281 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
282 {
283         DECLARE_WAITQUEUE(wait, current);
284         unsigned long data;
285         ssize_t retval;
286         struct hpet_dev *devp;
287
288         devp = file->private_data;
289         if (!devp->hd_ireqfreq)
290                 return -EIO;
291
292         if (count < sizeof(unsigned long))
293                 return -EINVAL;
294
295         add_wait_queue(&devp->hd_waitqueue, &wait);
296
297         for ( ; ; ) {
298                 set_current_state(TASK_INTERRUPTIBLE);
299
300                 spin_lock_irq(&hpet_lock);
301                 data = devp->hd_irqdata;
302                 devp->hd_irqdata = 0;
303                 spin_unlock_irq(&hpet_lock);
304
305                 if (data) {
306                         break;
307                 } else if (file->f_flags & O_NONBLOCK) {
308                         retval = -EAGAIN;
309                         goto out;
310                 } else if (signal_pending(current)) {
311                         retval = -ERESTARTSYS;
312                         goto out;
313                 }
314                 schedule();
315         }
316
317         retval = put_user(data, (unsigned long __user *)buf);
318         if (!retval)
319                 retval = sizeof(unsigned long);
320 out:
321         __set_current_state(TASK_RUNNING);
322         remove_wait_queue(&devp->hd_waitqueue, &wait);
323
324         return retval;
325 }
326
327 static __poll_t hpet_poll(struct file *file, poll_table * wait)
328 {
329         unsigned long v;
330         struct hpet_dev *devp;
331
332         devp = file->private_data;
333
334         if (!devp->hd_ireqfreq)
335                 return 0;
336
337         poll_wait(file, &devp->hd_waitqueue, wait);
338
339         spin_lock_irq(&hpet_lock);
340         v = devp->hd_irqdata;
341         spin_unlock_irq(&hpet_lock);
342
343         if (v != 0)
344                 return EPOLLIN | EPOLLRDNORM;
345
346         return 0;
347 }
348
349 #ifdef CONFIG_HPET_MMAP
350 #ifdef CONFIG_HPET_MMAP_DEFAULT
351 static int hpet_mmap_enabled = 1;
352 #else
353 static int hpet_mmap_enabled = 0;
354 #endif
355
356 static __init int hpet_mmap_enable(char *str)
357 {
358         get_option(&str, &hpet_mmap_enabled);
359         pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
360         return 1;
361 }
362 __setup("hpet_mmap=", hpet_mmap_enable);
363
364 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
365 {
366         struct hpet_dev *devp;
367         unsigned long addr;
368
369         if (!hpet_mmap_enabled)
370                 return -EACCES;
371
372         devp = file->private_data;
373         addr = devp->hd_hpets->hp_hpet_phys;
374
375         if (addr & (PAGE_SIZE - 1))
376                 return -ENOSYS;
377
378         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
379         return vm_iomap_memory(vma, addr, PAGE_SIZE);
380 }
381 #else
382 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
383 {
384         return -ENOSYS;
385 }
386 #endif
387
388 static int hpet_fasync(int fd, struct file *file, int on)
389 {
390         struct hpet_dev *devp;
391
392         devp = file->private_data;
393
394         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
395                 return 0;
396         else
397                 return -EIO;
398 }
399
400 static int hpet_release(struct inode *inode, struct file *file)
401 {
402         struct hpet_dev *devp;
403         struct hpet_timer __iomem *timer;
404         int irq = 0;
405
406         devp = file->private_data;
407         timer = devp->hd_timer;
408
409         spin_lock_irq(&hpet_lock);
410
411         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
412                &timer->hpet_config);
413
414         irq = devp->hd_irq;
415         devp->hd_irq = 0;
416
417         devp->hd_ireqfreq = 0;
418
419         if (devp->hd_flags & HPET_PERIODIC
420             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
421                 unsigned long v;
422
423                 v = readq(&timer->hpet_config);
424                 v ^= Tn_TYPE_CNF_MASK;
425                 writeq(v, &timer->hpet_config);
426         }
427
428         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
429         spin_unlock_irq(&hpet_lock);
430
431         if (irq)
432                 free_irq(irq, devp);
433
434         file->private_data = NULL;
435         return 0;
436 }
437
438 static int hpet_ioctl_ieon(struct hpet_dev *devp)
439 {
440         struct hpet_timer __iomem *timer;
441         struct hpet __iomem *hpet;
442         struct hpets *hpetp;
443         int irq;
444         unsigned long g, v, t, m;
445         unsigned long flags, isr;
446
447         timer = devp->hd_timer;
448         hpet = devp->hd_hpet;
449         hpetp = devp->hd_hpets;
450
451         if (!devp->hd_ireqfreq)
452                 return -EIO;
453
454         spin_lock_irq(&hpet_lock);
455
456         if (devp->hd_flags & HPET_IE) {
457                 spin_unlock_irq(&hpet_lock);
458                 return -EBUSY;
459         }
460
461         devp->hd_flags |= HPET_IE;
462
463         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
464                 devp->hd_flags |= HPET_SHARED_IRQ;
465         spin_unlock_irq(&hpet_lock);
466
467         irq = devp->hd_hdwirq;
468
469         if (irq) {
470                 unsigned long irq_flags;
471
472                 if (devp->hd_flags & HPET_SHARED_IRQ) {
473                         /*
474                          * To prevent the interrupt handler from seeing an
475                          * unwanted interrupt status bit, program the timer
476                          * so that it will not fire in the near future ...
477                          */
478                         writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
479                                &timer->hpet_config);
480                         write_counter(read_counter(&hpet->hpet_mc),
481                                       &timer->hpet_compare);
482                         /* ... and clear any left-over status. */
483                         isr = 1 << (devp - devp->hd_hpets->hp_dev);
484                         writel(isr, &hpet->hpet_isr);
485                 }
486
487                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
488                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
489                 if (request_irq(irq, hpet_interrupt, irq_flags,
490                                 devp->hd_name, (void *)devp)) {
491                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
492                         irq = 0;
493                 }
494         }
495
496         if (irq == 0) {
497                 spin_lock_irq(&hpet_lock);
498                 devp->hd_flags ^= HPET_IE;
499                 spin_unlock_irq(&hpet_lock);
500                 return -EIO;
501         }
502
503         devp->hd_irq = irq;
504         t = devp->hd_ireqfreq;
505         v = readq(&timer->hpet_config);
506
507         /* 64-bit comparators are not yet supported through the ioctls,
508          * so force this into 32-bit mode if it supports both modes
509          */
510         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
511
512         if (devp->hd_flags & HPET_PERIODIC) {
513                 g |= Tn_TYPE_CNF_MASK;
514                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
515                 writeq(v, &timer->hpet_config);
516                 local_irq_save(flags);
517
518                 /*
519                  * NOTE: First we modify the hidden accumulator
520                  * register supported by periodic-capable comparators.
521                  * We never want to modify the (single) counter; that
522                  * would affect all the comparators. The value written
523                  * is the counter value when the first interrupt is due.
524                  */
525                 m = read_counter(&hpet->hpet_mc);
526                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
527                 /*
528                  * Then we modify the comparator, indicating the period
529                  * for subsequent interrupt.
530                  */
531                 write_counter(t, &timer->hpet_compare);
532         } else {
533                 local_irq_save(flags);
534                 m = read_counter(&hpet->hpet_mc);
535                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
536         }
537
538         if (devp->hd_flags & HPET_SHARED_IRQ) {
539                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
540                 writel(isr, &hpet->hpet_isr);
541         }
542         writeq(g, &timer->hpet_config);
543         local_irq_restore(flags);
544
545         return 0;
546 }
547
548 /* converts Hz to number of timer ticks */
549 static inline unsigned long hpet_time_div(struct hpets *hpets,
550                                           unsigned long dis)
551 {
552         unsigned long long m;
553
554         m = hpets->hp_tick_freq + (dis >> 1);
555         return div64_ul(m, dis);
556 }
557
558 static int
559 hpet_ioctl_common(struct hpet_dev *devp, unsigned int cmd, unsigned long arg,
560                   struct hpet_info *info)
561 {
562         struct hpet_timer __iomem *timer;
563         struct hpets *hpetp;
564         int err;
565         unsigned long v;
566
567         switch (cmd) {
568         case HPET_IE_OFF:
569         case HPET_INFO:
570         case HPET_EPI:
571         case HPET_DPI:
572         case HPET_IRQFREQ:
573                 timer = devp->hd_timer;
574                 hpetp = devp->hd_hpets;
575                 break;
576         case HPET_IE_ON:
577                 return hpet_ioctl_ieon(devp);
578         default:
579                 return -EINVAL;
580         }
581
582         err = 0;
583
584         switch (cmd) {
585         case HPET_IE_OFF:
586                 if ((devp->hd_flags & HPET_IE) == 0)
587                         break;
588                 v = readq(&timer->hpet_config);
589                 v &= ~Tn_INT_ENB_CNF_MASK;
590                 writeq(v, &timer->hpet_config);
591                 if (devp->hd_irq) {
592                         free_irq(devp->hd_irq, devp);
593                         devp->hd_irq = 0;
594                 }
595                 devp->hd_flags ^= HPET_IE;
596                 break;
597         case HPET_INFO:
598                 {
599                         memset(info, 0, sizeof(*info));
600                         if (devp->hd_ireqfreq)
601                                 info->hi_ireqfreq =
602                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
603                         info->hi_flags =
604                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
605                         info->hi_hpet = hpetp->hp_which;
606                         info->hi_timer = devp - hpetp->hp_dev;
607                         break;
608                 }
609         case HPET_EPI:
610                 v = readq(&timer->hpet_config);
611                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
612                         err = -ENXIO;
613                         break;
614                 }
615                 devp->hd_flags |= HPET_PERIODIC;
616                 break;
617         case HPET_DPI:
618                 v = readq(&timer->hpet_config);
619                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
620                         err = -ENXIO;
621                         break;
622                 }
623                 if (devp->hd_flags & HPET_PERIODIC &&
624                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
625                         v = readq(&timer->hpet_config);
626                         v ^= Tn_TYPE_CNF_MASK;
627                         writeq(v, &timer->hpet_config);
628                 }
629                 devp->hd_flags &= ~HPET_PERIODIC;
630                 break;
631         case HPET_IRQFREQ:
632                 if ((arg > hpet_max_freq) &&
633                     !capable(CAP_SYS_RESOURCE)) {
634                         err = -EACCES;
635                         break;
636                 }
637
638                 if (!arg) {
639                         err = -EINVAL;
640                         break;
641                 }
642
643                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
644         }
645
646         return err;
647 }
648
649 static long
650 hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
651 {
652         struct hpet_info info;
653         int err;
654
655         mutex_lock(&hpet_mutex);
656         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
657         mutex_unlock(&hpet_mutex);
658
659         if ((cmd == HPET_INFO) && !err &&
660             (copy_to_user((void __user *)arg, &info, sizeof(info))))
661                 err = -EFAULT;
662
663         return err;
664 }
665
666 #ifdef CONFIG_COMPAT
667 struct compat_hpet_info {
668         compat_ulong_t hi_ireqfreq;     /* Hz */
669         compat_ulong_t hi_flags;        /* information */
670         unsigned short hi_hpet;
671         unsigned short hi_timer;
672 };
673
674 static long
675 hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
676 {
677         struct hpet_info info;
678         int err;
679
680         mutex_lock(&hpet_mutex);
681         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
682         mutex_unlock(&hpet_mutex);
683
684         if ((cmd == HPET_INFO) && !err) {
685                 struct compat_hpet_info __user *u = compat_ptr(arg);
686                 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
687                     put_user(info.hi_flags, &u->hi_flags) ||
688                     put_user(info.hi_hpet, &u->hi_hpet) ||
689                     put_user(info.hi_timer, &u->hi_timer))
690                         err = -EFAULT;
691         }
692
693         return err;
694 }
695 #endif
696
697 static const struct file_operations hpet_fops = {
698         .owner = THIS_MODULE,
699         .llseek = no_llseek,
700         .read = hpet_read,
701         .poll = hpet_poll,
702         .unlocked_ioctl = hpet_ioctl,
703 #ifdef CONFIG_COMPAT
704         .compat_ioctl = hpet_compat_ioctl,
705 #endif
706         .open = hpet_open,
707         .release = hpet_release,
708         .fasync = hpet_fasync,
709         .mmap = hpet_mmap,
710 };
711
712 static int hpet_is_known(struct hpet_data *hdp)
713 {
714         struct hpets *hpetp;
715
716         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
717                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
718                         return 1;
719
720         return 0;
721 }
722
723 static struct ctl_table hpet_table[] = {
724         {
725          .procname = "max-user-freq",
726          .data = &hpet_max_freq,
727          .maxlen = sizeof(int),
728          .mode = 0644,
729          .proc_handler = proc_dointvec,
730          },
731         {}
732 };
733
734 static struct ctl_table_header *sysctl_header;
735
736 /*
737  * Adjustment for when arming the timer with
738  * initial conditions.  That is, main counter
739  * ticks expired before interrupts are enabled.
740  */
741 #define TICK_CALIBRATE  (1000UL)
742
743 static unsigned long __hpet_calibrate(struct hpets *hpetp)
744 {
745         struct hpet_timer __iomem *timer = NULL;
746         unsigned long t, m, count, i, flags, start;
747         struct hpet_dev *devp;
748         int j;
749         struct hpet __iomem *hpet;
750
751         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
752                 if ((devp->hd_flags & HPET_OPEN) == 0) {
753                         timer = devp->hd_timer;
754                         break;
755                 }
756
757         if (!timer)
758                 return 0;
759
760         hpet = hpetp->hp_hpet;
761         t = read_counter(&timer->hpet_compare);
762
763         i = 0;
764         count = hpet_time_div(hpetp, TICK_CALIBRATE);
765
766         local_irq_save(flags);
767
768         start = read_counter(&hpet->hpet_mc);
769
770         do {
771                 m = read_counter(&hpet->hpet_mc);
772                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
773         } while (i++, (m - start) < count);
774
775         local_irq_restore(flags);
776
777         return (m - start) / i;
778 }
779
780 static unsigned long hpet_calibrate(struct hpets *hpetp)
781 {
782         unsigned long ret = ~0UL;
783         unsigned long tmp;
784
785         /*
786          * Try to calibrate until return value becomes stable small value.
787          * If SMI interruption occurs in calibration loop, the return value
788          * will be big. This avoids its impact.
789          */
790         for ( ; ; ) {
791                 tmp = __hpet_calibrate(hpetp);
792                 if (ret <= tmp)
793                         break;
794                 ret = tmp;
795         }
796
797         return ret;
798 }
799
800 int hpet_alloc(struct hpet_data *hdp)
801 {
802         u64 cap, mcfg;
803         struct hpet_dev *devp;
804         u32 i, ntimer;
805         struct hpets *hpetp;
806         struct hpet __iomem *hpet;
807         static struct hpets *last;
808         unsigned long period;
809         unsigned long long temp;
810         u32 remainder;
811
812         /*
813          * hpet_alloc can be called by platform dependent code.
814          * If platform dependent code has allocated the hpet that
815          * ACPI has also reported, then we catch it here.
816          */
817         if (hpet_is_known(hdp)) {
818                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
819                         __func__);
820                 return 0;
821         }
822
823         hpetp = kzalloc(struct_size(hpetp, hp_dev, hdp->hd_nirqs),
824                         GFP_KERNEL);
825
826         if (!hpetp)
827                 return -ENOMEM;
828
829         hpetp->hp_which = hpet_nhpet++;
830         hpetp->hp_hpet = hdp->hd_address;
831         hpetp->hp_hpet_phys = hdp->hd_phys_address;
832
833         hpetp->hp_ntimer = hdp->hd_nirqs;
834
835         for (i = 0; i < hdp->hd_nirqs; i++)
836                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
837
838         hpet = hpetp->hp_hpet;
839
840         cap = readq(&hpet->hpet_cap);
841
842         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
843
844         if (hpetp->hp_ntimer != ntimer) {
845                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
846                        " with number of timers\n");
847                 kfree(hpetp);
848                 return -ENODEV;
849         }
850
851         if (last)
852                 last->hp_next = hpetp;
853         else
854                 hpets = hpetp;
855
856         last = hpetp;
857
858         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
859                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
860         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
861         temp += period >> 1; /* round */
862         do_div(temp, period);
863         hpetp->hp_tick_freq = temp; /* ticks per second */
864
865         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
866                 hpetp->hp_which, hdp->hd_phys_address,
867                 hpetp->hp_ntimer > 1 ? "s" : "");
868         for (i = 0; i < hpetp->hp_ntimer; i++)
869                 printk(KERN_CONT "%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
870         printk(KERN_CONT "\n");
871
872         temp = hpetp->hp_tick_freq;
873         remainder = do_div(temp, 1000000);
874         printk(KERN_INFO
875                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
876                 hpetp->hp_which, hpetp->hp_ntimer,
877                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
878                 (unsigned) temp, remainder);
879
880         mcfg = readq(&hpet->hpet_config);
881         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
882                 write_counter(0L, &hpet->hpet_mc);
883                 mcfg |= HPET_ENABLE_CNF_MASK;
884                 writeq(mcfg, &hpet->hpet_config);
885         }
886
887         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
888                 struct hpet_timer __iomem *timer;
889
890                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
891
892                 devp->hd_hpets = hpetp;
893                 devp->hd_hpet = hpet;
894                 devp->hd_timer = timer;
895
896                 /*
897                  * If the timer was reserved by platform code,
898                  * then make timer unavailable for opens.
899                  */
900                 if (hdp->hd_state & (1 << i)) {
901                         devp->hd_flags = HPET_OPEN;
902                         continue;
903                 }
904
905                 init_waitqueue_head(&devp->hd_waitqueue);
906         }
907
908         hpetp->hp_delta = hpet_calibrate(hpetp);
909
910 /* This clocksource driver currently only works on ia64 */
911 #ifdef CONFIG_IA64
912         if (!hpet_clocksource) {
913                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
914                 clocksource_hpet.archdata.fsys_mmio = hpet_mctr;
915                 clocksource_register_hz(&clocksource_hpet, hpetp->hp_tick_freq);
916                 hpetp->hp_clocksource = &clocksource_hpet;
917                 hpet_clocksource = &clocksource_hpet;
918         }
919 #endif
920
921         return 0;
922 }
923
924 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
925 {
926         struct hpet_data *hdp;
927         acpi_status status;
928         struct acpi_resource_address64 addr;
929
930         hdp = data;
931
932         status = acpi_resource_to_address64(res, &addr);
933
934         if (ACPI_SUCCESS(status)) {
935                 hdp->hd_phys_address = addr.address.minimum;
936                 hdp->hd_address = ioremap(addr.address.minimum, addr.address.address_length);
937                 if (!hdp->hd_address)
938                         return AE_ERROR;
939
940                 if (hpet_is_known(hdp)) {
941                         iounmap(hdp->hd_address);
942                         return AE_ALREADY_EXISTS;
943                 }
944         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
945                 struct acpi_resource_fixed_memory32 *fixmem32;
946
947                 fixmem32 = &res->data.fixed_memory32;
948
949                 hdp->hd_phys_address = fixmem32->address;
950                 hdp->hd_address = ioremap(fixmem32->address,
951                                                 HPET_RANGE_SIZE);
952                 if (!hdp->hd_address)
953                         return AE_ERROR;
954
955                 if (hpet_is_known(hdp)) {
956                         iounmap(hdp->hd_address);
957                         return AE_ALREADY_EXISTS;
958                 }
959         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
960                 struct acpi_resource_extended_irq *irqp;
961                 int i, irq;
962
963                 irqp = &res->data.extended_irq;
964
965                 for (i = 0; i < irqp->interrupt_count; i++) {
966                         if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
967                                 break;
968
969                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
970                                                 irqp->triggering,
971                                                 irqp->polarity);
972                         if (irq < 0)
973                                 return AE_ERROR;
974
975                         hdp->hd_irq[hdp->hd_nirqs] = irq;
976                         hdp->hd_nirqs++;
977                 }
978         }
979
980         return AE_OK;
981 }
982
983 static int hpet_acpi_add(struct acpi_device *device)
984 {
985         acpi_status result;
986         struct hpet_data data;
987
988         memset(&data, 0, sizeof(data));
989
990         result =
991             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
992                                 hpet_resources, &data);
993
994         if (ACPI_FAILURE(result))
995                 return -ENODEV;
996
997         if (!data.hd_address || !data.hd_nirqs) {
998                 if (data.hd_address)
999                         iounmap(data.hd_address);
1000                 printk("%s: no address or irqs in _CRS\n", __func__);
1001                 return -ENODEV;
1002         }
1003
1004         return hpet_alloc(&data);
1005 }
1006
1007 static const struct acpi_device_id hpet_device_ids[] = {
1008         {"PNP0103", 0},
1009         {"", 0},
1010 };
1011
1012 static struct acpi_driver hpet_acpi_driver = {
1013         .name = "hpet",
1014         .ids = hpet_device_ids,
1015         .ops = {
1016                 .add = hpet_acpi_add,
1017                 },
1018 };
1019
1020 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1021
1022 static int __init hpet_init(void)
1023 {
1024         int result;
1025
1026         result = misc_register(&hpet_misc);
1027         if (result < 0)
1028                 return -ENODEV;
1029
1030         sysctl_header = register_sysctl("dev/hpet", hpet_table);
1031
1032         result = acpi_bus_register_driver(&hpet_acpi_driver);
1033         if (result < 0) {
1034                 if (sysctl_header)
1035                         unregister_sysctl_table(sysctl_header);
1036                 misc_deregister(&hpet_misc);
1037                 return result;
1038         }
1039
1040         return 0;
1041 }
1042 device_initcall(hpet_init);
1043
1044 /*
1045 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1046 MODULE_LICENSE("GPL");
1047 */