documentation: move hpet.txt to timers/ subdirectory
[sfrench/cifs-2.6.git] / drivers / char / hpet.c
1 /*
2  * Intel & MS High Precision Event Timer Implementation.
3  *
4  * Copyright (C) 2003 Intel Corporation
5  *      Venki Pallipadi
6  * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
7  *      Bob Picco <robert.picco@hp.com>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13
14 #include <linux/interrupt.h>
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/types.h>
18 #include <linux/miscdevice.h>
19 #include <linux/major.h>
20 #include <linux/ioport.h>
21 #include <linux/fcntl.h>
22 #include <linux/init.h>
23 #include <linux/poll.h>
24 #include <linux/mm.h>
25 #include <linux/proc_fs.h>
26 #include <linux/spinlock.h>
27 #include <linux/sysctl.h>
28 #include <linux/wait.h>
29 #include <linux/bcd.h>
30 #include <linux/seq_file.h>
31 #include <linux/bitops.h>
32 #include <linux/clocksource.h>
33
34 #include <asm/current.h>
35 #include <asm/uaccess.h>
36 #include <asm/system.h>
37 #include <asm/io.h>
38 #include <asm/irq.h>
39 #include <asm/div64.h>
40
41 #include <linux/acpi.h>
42 #include <acpi/acpi_bus.h>
43 #include <linux/hpet.h>
44
45 /*
46  * The High Precision Event Timer driver.
47  * This driver is closely modelled after the rtc.c driver.
48  * http://www.intel.com/hardwaredesign/hpetspec.htm
49  */
50 #define HPET_USER_FREQ  (64)
51 #define HPET_DRIFT      (500)
52
53 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
54
55 #if BITS_PER_LONG == 64
56 #define write_counter(V, MC)    writeq(V, MC)
57 #define read_counter(MC)        readq(MC)
58 #else
59 #define write_counter(V, MC)    writel(V, MC)
60 #define read_counter(MC)        readl(MC)
61 #endif
62
63 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
64
65 /* This clocksource driver currently only works on ia64 */
66 #ifdef CONFIG_IA64
67 static void __iomem *hpet_mctr;
68
69 static cycle_t read_hpet(void)
70 {
71         return (cycle_t)read_counter((void __iomem *)hpet_mctr);
72 }
73
74 static struct clocksource clocksource_hpet = {
75         .name           = "hpet",
76         .rating         = 250,
77         .read           = read_hpet,
78         .mask           = CLOCKSOURCE_MASK(64),
79         .mult           = 0, /*to be caluclated*/
80         .shift          = 10,
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 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
89 static DEFINE_SPINLOCK(hpet_task_lock);
90
91 #define HPET_DEV_NAME   (7)
92
93 struct hpet_dev {
94         struct hpets *hd_hpets;
95         struct hpet __iomem *hd_hpet;
96         struct hpet_timer __iomem *hd_timer;
97         unsigned long hd_ireqfreq;
98         unsigned long hd_irqdata;
99         wait_queue_head_t hd_waitqueue;
100         struct fasync_struct *hd_async_queue;
101         struct hpet_task *hd_task;
102         unsigned int hd_flags;
103         unsigned int hd_irq;
104         unsigned int hd_hdwirq;
105         char hd_name[HPET_DEV_NAME];
106 };
107
108 struct hpets {
109         struct hpets *hp_next;
110         struct hpet __iomem *hp_hpet;
111         unsigned long hp_hpet_phys;
112         struct clocksource *hp_clocksource;
113         unsigned long long hp_tick_freq;
114         unsigned long hp_delta;
115         unsigned int hp_ntimer;
116         unsigned int hp_which;
117         struct hpet_dev hp_dev[1];
118 };
119
120 static struct hpets *hpets;
121
122 #define HPET_OPEN               0x0001
123 #define HPET_IE                 0x0002  /* interrupt enabled */
124 #define HPET_PERIODIC           0x0004
125 #define HPET_SHARED_IRQ         0x0008
126
127
128 #ifndef readq
129 static inline unsigned long long readq(void __iomem *addr)
130 {
131         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
132 }
133 #endif
134
135 #ifndef writeq
136 static inline void writeq(unsigned long long v, void __iomem *addr)
137 {
138         writel(v & 0xffffffff, addr);
139         writel(v >> 32, addr + 4);
140 }
141 #endif
142
143 static irqreturn_t hpet_interrupt(int irq, void *data)
144 {
145         struct hpet_dev *devp;
146         unsigned long isr;
147
148         devp = data;
149         isr = 1 << (devp - devp->hd_hpets->hp_dev);
150
151         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
152             !(isr & readl(&devp->hd_hpet->hpet_isr)))
153                 return IRQ_NONE;
154
155         spin_lock(&hpet_lock);
156         devp->hd_irqdata++;
157
158         /*
159          * For non-periodic timers, increment the accumulator.
160          * This has the effect of treating non-periodic like periodic.
161          */
162         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
163                 unsigned long m, t;
164
165                 t = devp->hd_ireqfreq;
166                 m = read_counter(&devp->hd_hpet->hpet_mc);
167                 write_counter(t + m + devp->hd_hpets->hp_delta,
168                               &devp->hd_timer->hpet_compare);
169         }
170
171         if (devp->hd_flags & HPET_SHARED_IRQ)
172                 writel(isr, &devp->hd_hpet->hpet_isr);
173         spin_unlock(&hpet_lock);
174
175         spin_lock(&hpet_task_lock);
176         if (devp->hd_task)
177                 devp->hd_task->ht_func(devp->hd_task->ht_data);
178         spin_unlock(&hpet_task_lock);
179
180         wake_up_interruptible(&devp->hd_waitqueue);
181
182         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
183
184         return IRQ_HANDLED;
185 }
186
187 static void hpet_timer_set_irq(struct hpet_dev *devp)
188 {
189         unsigned long v;
190         int irq, gsi;
191         struct hpet_timer __iomem *timer;
192
193         spin_lock_irq(&hpet_lock);
194         if (devp->hd_hdwirq) {
195                 spin_unlock_irq(&hpet_lock);
196                 return;
197         }
198
199         timer = devp->hd_timer;
200
201         /* we prefer level triggered mode */
202         v = readl(&timer->hpet_config);
203         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
204                 v |= Tn_INT_TYPE_CNF_MASK;
205                 writel(v, &timer->hpet_config);
206         }
207         spin_unlock_irq(&hpet_lock);
208
209         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
210                                  Tn_INT_ROUTE_CAP_SHIFT;
211
212         /*
213          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
214          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
215          */
216         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
217                 v &= ~0xf3df;
218         else
219                 v &= ~0xffff;
220
221         for (irq = find_first_bit(&v, HPET_MAX_IRQ); irq < HPET_MAX_IRQ;
222                 irq = find_next_bit(&v, HPET_MAX_IRQ, 1 + irq)) {
223
224                 if (irq >= NR_IRQS) {
225                         irq = HPET_MAX_IRQ;
226                         break;
227                 }
228
229                 gsi = acpi_register_gsi(irq, ACPI_LEVEL_SENSITIVE,
230                                         ACPI_ACTIVE_LOW);
231                 if (gsi > 0)
232                         break;
233
234                 /* FIXME: Setup interrupt source table */
235         }
236
237         if (irq < HPET_MAX_IRQ) {
238                 spin_lock_irq(&hpet_lock);
239                 v = readl(&timer->hpet_config);
240                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
241                 writel(v, &timer->hpet_config);
242                 devp->hd_hdwirq = gsi;
243                 spin_unlock_irq(&hpet_lock);
244         }
245         return;
246 }
247
248 static int hpet_open(struct inode *inode, struct file *file)
249 {
250         struct hpet_dev *devp;
251         struct hpets *hpetp;
252         int i;
253
254         if (file->f_mode & FMODE_WRITE)
255                 return -EINVAL;
256
257         spin_lock_irq(&hpet_lock);
258
259         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
260                 for (i = 0; i < hpetp->hp_ntimer; i++)
261                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
262                             || hpetp->hp_dev[i].hd_task)
263                                 continue;
264                         else {
265                                 devp = &hpetp->hp_dev[i];
266                                 break;
267                         }
268
269         if (!devp) {
270                 spin_unlock_irq(&hpet_lock);
271                 return -EBUSY;
272         }
273
274         file->private_data = devp;
275         devp->hd_irqdata = 0;
276         devp->hd_flags |= HPET_OPEN;
277         spin_unlock_irq(&hpet_lock);
278
279         hpet_timer_set_irq(devp);
280
281         return 0;
282 }
283
284 static ssize_t
285 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
286 {
287         DECLARE_WAITQUEUE(wait, current);
288         unsigned long data;
289         ssize_t retval;
290         struct hpet_dev *devp;
291
292         devp = file->private_data;
293         if (!devp->hd_ireqfreq)
294                 return -EIO;
295
296         if (count < sizeof(unsigned long))
297                 return -EINVAL;
298
299         add_wait_queue(&devp->hd_waitqueue, &wait);
300
301         for ( ; ; ) {
302                 set_current_state(TASK_INTERRUPTIBLE);
303
304                 spin_lock_irq(&hpet_lock);
305                 data = devp->hd_irqdata;
306                 devp->hd_irqdata = 0;
307                 spin_unlock_irq(&hpet_lock);
308
309                 if (data)
310                         break;
311                 else if (file->f_flags & O_NONBLOCK) {
312                         retval = -EAGAIN;
313                         goto out;
314                 } else if (signal_pending(current)) {
315                         retval = -ERESTARTSYS;
316                         goto out;
317                 }
318                 schedule();
319         }
320
321         retval = put_user(data, (unsigned long __user *)buf);
322         if (!retval)
323                 retval = sizeof(unsigned long);
324 out:
325         __set_current_state(TASK_RUNNING);
326         remove_wait_queue(&devp->hd_waitqueue, &wait);
327
328         return retval;
329 }
330
331 static unsigned int hpet_poll(struct file *file, poll_table * wait)
332 {
333         unsigned long v;
334         struct hpet_dev *devp;
335
336         devp = file->private_data;
337
338         if (!devp->hd_ireqfreq)
339                 return 0;
340
341         poll_wait(file, &devp->hd_waitqueue, wait);
342
343         spin_lock_irq(&hpet_lock);
344         v = devp->hd_irqdata;
345         spin_unlock_irq(&hpet_lock);
346
347         if (v != 0)
348                 return POLLIN | POLLRDNORM;
349
350         return 0;
351 }
352
353 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
354 {
355 #ifdef  CONFIG_HPET_MMAP
356         struct hpet_dev *devp;
357         unsigned long addr;
358
359         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
360                 return -EINVAL;
361
362         devp = file->private_data;
363         addr = devp->hd_hpets->hp_hpet_phys;
364
365         if (addr & (PAGE_SIZE - 1))
366                 return -ENOSYS;
367
368         vma->vm_flags |= VM_IO;
369         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
370
371         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
372                                         PAGE_SIZE, vma->vm_page_prot)) {
373                 printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
374                         __func__);
375                 return -EAGAIN;
376         }
377
378         return 0;
379 #else
380         return -ENOSYS;
381 #endif
382 }
383
384 static int hpet_fasync(int fd, struct file *file, int on)
385 {
386         struct hpet_dev *devp;
387
388         devp = file->private_data;
389
390         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
391                 return 0;
392         else
393                 return -EIO;
394 }
395
396 static int hpet_release(struct inode *inode, struct file *file)
397 {
398         struct hpet_dev *devp;
399         struct hpet_timer __iomem *timer;
400         int irq = 0;
401
402         devp = file->private_data;
403         timer = devp->hd_timer;
404
405         spin_lock_irq(&hpet_lock);
406
407         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
408                &timer->hpet_config);
409
410         irq = devp->hd_irq;
411         devp->hd_irq = 0;
412
413         devp->hd_ireqfreq = 0;
414
415         if (devp->hd_flags & HPET_PERIODIC
416             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
417                 unsigned long v;
418
419                 v = readq(&timer->hpet_config);
420                 v ^= Tn_TYPE_CNF_MASK;
421                 writeq(v, &timer->hpet_config);
422         }
423
424         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
425         spin_unlock_irq(&hpet_lock);
426
427         if (irq)
428                 free_irq(irq, devp);
429
430         if (file->f_flags & FASYNC)
431                 hpet_fasync(-1, file, 0);
432
433         file->private_data = NULL;
434         return 0;
435 }
436
437 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
438
439 static int
440 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
441            unsigned long arg)
442 {
443         struct hpet_dev *devp;
444
445         devp = file->private_data;
446         return hpet_ioctl_common(devp, cmd, arg, 0);
447 }
448
449 static int hpet_ioctl_ieon(struct hpet_dev *devp)
450 {
451         struct hpet_timer __iomem *timer;
452         struct hpet __iomem *hpet;
453         struct hpets *hpetp;
454         int irq;
455         unsigned long g, v, t, m;
456         unsigned long flags, isr;
457
458         timer = devp->hd_timer;
459         hpet = devp->hd_hpet;
460         hpetp = devp->hd_hpets;
461
462         if (!devp->hd_ireqfreq)
463                 return -EIO;
464
465         spin_lock_irq(&hpet_lock);
466
467         if (devp->hd_flags & HPET_IE) {
468                 spin_unlock_irq(&hpet_lock);
469                 return -EBUSY;
470         }
471
472         devp->hd_flags |= HPET_IE;
473
474         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
475                 devp->hd_flags |= HPET_SHARED_IRQ;
476         spin_unlock_irq(&hpet_lock);
477
478         irq = devp->hd_hdwirq;
479
480         if (irq) {
481                 unsigned long irq_flags;
482
483                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
484                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
485                                                 ? IRQF_SHARED : IRQF_DISABLED;
486                 if (request_irq(irq, hpet_interrupt, irq_flags,
487                                 devp->hd_name, (void *)devp)) {
488                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
489                         irq = 0;
490                 }
491         }
492
493         if (irq == 0) {
494                 spin_lock_irq(&hpet_lock);
495                 devp->hd_flags ^= HPET_IE;
496                 spin_unlock_irq(&hpet_lock);
497                 return -EIO;
498         }
499
500         devp->hd_irq = irq;
501         t = devp->hd_ireqfreq;
502         v = readq(&timer->hpet_config);
503         g = v | Tn_INT_ENB_CNF_MASK;
504
505         if (devp->hd_flags & HPET_PERIODIC) {
506                 write_counter(t, &timer->hpet_compare);
507                 g |= Tn_TYPE_CNF_MASK;
508                 v |= Tn_TYPE_CNF_MASK;
509                 writeq(v, &timer->hpet_config);
510                 v |= Tn_VAL_SET_CNF_MASK;
511                 writeq(v, &timer->hpet_config);
512                 local_irq_save(flags);
513                 m = read_counter(&hpet->hpet_mc);
514                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
515         } else {
516                 local_irq_save(flags);
517                 m = read_counter(&hpet->hpet_mc);
518                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
519         }
520
521         if (devp->hd_flags & HPET_SHARED_IRQ) {
522                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
523                 writel(isr, &hpet->hpet_isr);
524         }
525         writeq(g, &timer->hpet_config);
526         local_irq_restore(flags);
527
528         return 0;
529 }
530
531 /* converts Hz to number of timer ticks */
532 static inline unsigned long hpet_time_div(struct hpets *hpets,
533                                           unsigned long dis)
534 {
535         unsigned long long m;
536
537         m = hpets->hp_tick_freq + (dis >> 1);
538         do_div(m, dis);
539         return (unsigned long)m;
540 }
541
542 static int
543 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
544 {
545         struct hpet_timer __iomem *timer;
546         struct hpet __iomem *hpet;
547         struct hpets *hpetp;
548         int err;
549         unsigned long v;
550
551         switch (cmd) {
552         case HPET_IE_OFF:
553         case HPET_INFO:
554         case HPET_EPI:
555         case HPET_DPI:
556         case HPET_IRQFREQ:
557                 timer = devp->hd_timer;
558                 hpet = devp->hd_hpet;
559                 hpetp = devp->hd_hpets;
560                 break;
561         case HPET_IE_ON:
562                 return hpet_ioctl_ieon(devp);
563         default:
564                 return -EINVAL;
565         }
566
567         err = 0;
568
569         switch (cmd) {
570         case HPET_IE_OFF:
571                 if ((devp->hd_flags & HPET_IE) == 0)
572                         break;
573                 v = readq(&timer->hpet_config);
574                 v &= ~Tn_INT_ENB_CNF_MASK;
575                 writeq(v, &timer->hpet_config);
576                 if (devp->hd_irq) {
577                         free_irq(devp->hd_irq, devp);
578                         devp->hd_irq = 0;
579                 }
580                 devp->hd_flags ^= HPET_IE;
581                 break;
582         case HPET_INFO:
583                 {
584                         struct hpet_info info;
585
586                         if (devp->hd_ireqfreq)
587                                 info.hi_ireqfreq =
588                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
589                         else
590                                 info.hi_ireqfreq = 0;
591                         info.hi_flags =
592                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
593                         info.hi_hpet = hpetp->hp_which;
594                         info.hi_timer = devp - hpetp->hp_dev;
595                         if (kernel)
596                                 memcpy((void *)arg, &info, sizeof(info));
597                         else
598                                 if (copy_to_user((void __user *)arg, &info,
599                                                  sizeof(info)))
600                                         err = -EFAULT;
601                         break;
602                 }
603         case HPET_EPI:
604                 v = readq(&timer->hpet_config);
605                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
606                         err = -ENXIO;
607                         break;
608                 }
609                 devp->hd_flags |= HPET_PERIODIC;
610                 break;
611         case HPET_DPI:
612                 v = readq(&timer->hpet_config);
613                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
614                         err = -ENXIO;
615                         break;
616                 }
617                 if (devp->hd_flags & HPET_PERIODIC &&
618                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
619                         v = readq(&timer->hpet_config);
620                         v ^= Tn_TYPE_CNF_MASK;
621                         writeq(v, &timer->hpet_config);
622                 }
623                 devp->hd_flags &= ~HPET_PERIODIC;
624                 break;
625         case HPET_IRQFREQ:
626                 if (!kernel && (arg > hpet_max_freq) &&
627                     !capable(CAP_SYS_RESOURCE)) {
628                         err = -EACCES;
629                         break;
630                 }
631
632                 if (!arg) {
633                         err = -EINVAL;
634                         break;
635                 }
636
637                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
638         }
639
640         return err;
641 }
642
643 static const struct file_operations hpet_fops = {
644         .owner = THIS_MODULE,
645         .llseek = no_llseek,
646         .read = hpet_read,
647         .poll = hpet_poll,
648         .ioctl = hpet_ioctl,
649         .open = hpet_open,
650         .release = hpet_release,
651         .fasync = hpet_fasync,
652         .mmap = hpet_mmap,
653 };
654
655 static int hpet_is_known(struct hpet_data *hdp)
656 {
657         struct hpets *hpetp;
658
659         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
660                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
661                         return 1;
662
663         return 0;
664 }
665
666 static inline int hpet_tpcheck(struct hpet_task *tp)
667 {
668         struct hpet_dev *devp;
669         struct hpets *hpetp;
670
671         devp = tp->ht_opaque;
672
673         if (!devp)
674                 return -ENXIO;
675
676         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
677                 if (devp >= hpetp->hp_dev
678                     && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
679                     && devp->hd_hpet == hpetp->hp_hpet)
680                         return 0;
681
682         return -ENXIO;
683 }
684
685 int hpet_unregister(struct hpet_task *tp)
686 {
687         struct hpet_dev *devp;
688         struct hpet_timer __iomem *timer;
689         int err;
690
691         if ((err = hpet_tpcheck(tp)))
692                 return err;
693
694         spin_lock_irq(&hpet_task_lock);
695         spin_lock(&hpet_lock);
696
697         devp = tp->ht_opaque;
698         if (devp->hd_task != tp) {
699                 spin_unlock(&hpet_lock);
700                 spin_unlock_irq(&hpet_task_lock);
701                 return -ENXIO;
702         }
703
704         timer = devp->hd_timer;
705         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
706                &timer->hpet_config);
707         devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
708         devp->hd_task = NULL;
709         spin_unlock(&hpet_lock);
710         spin_unlock_irq(&hpet_task_lock);
711
712         return 0;
713 }
714
715 static ctl_table hpet_table[] = {
716         {
717          .ctl_name = CTL_UNNUMBERED,
718          .procname = "max-user-freq",
719          .data = &hpet_max_freq,
720          .maxlen = sizeof(int),
721          .mode = 0644,
722          .proc_handler = &proc_dointvec,
723          },
724         {.ctl_name = 0}
725 };
726
727 static ctl_table hpet_root[] = {
728         {
729          .ctl_name = CTL_UNNUMBERED,
730          .procname = "hpet",
731          .maxlen = 0,
732          .mode = 0555,
733          .child = hpet_table,
734          },
735         {.ctl_name = 0}
736 };
737
738 static ctl_table dev_root[] = {
739         {
740          .ctl_name = CTL_DEV,
741          .procname = "dev",
742          .maxlen = 0,
743          .mode = 0555,
744          .child = hpet_root,
745          },
746         {.ctl_name = 0}
747 };
748
749 static struct ctl_table_header *sysctl_header;
750
751 /*
752  * Adjustment for when arming the timer with
753  * initial conditions.  That is, main counter
754  * ticks expired before interrupts are enabled.
755  */
756 #define TICK_CALIBRATE  (1000UL)
757
758 static unsigned long hpet_calibrate(struct hpets *hpetp)
759 {
760         struct hpet_timer __iomem *timer = NULL;
761         unsigned long t, m, count, i, flags, start;
762         struct hpet_dev *devp;
763         int j;
764         struct hpet __iomem *hpet;
765
766         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
767                 if ((devp->hd_flags & HPET_OPEN) == 0) {
768                         timer = devp->hd_timer;
769                         break;
770                 }
771
772         if (!timer)
773                 return 0;
774
775         hpet = hpetp->hp_hpet;
776         t = read_counter(&timer->hpet_compare);
777
778         i = 0;
779         count = hpet_time_div(hpetp, TICK_CALIBRATE);
780
781         local_irq_save(flags);
782
783         start = read_counter(&hpet->hpet_mc);
784
785         do {
786                 m = read_counter(&hpet->hpet_mc);
787                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
788         } while (i++, (m - start) < count);
789
790         local_irq_restore(flags);
791
792         return (m - start) / i;
793 }
794
795 int hpet_alloc(struct hpet_data *hdp)
796 {
797         u64 cap, mcfg;
798         struct hpet_dev *devp;
799         u32 i, ntimer;
800         struct hpets *hpetp;
801         size_t siz;
802         struct hpet __iomem *hpet;
803         static struct hpets *last = NULL;
804         unsigned long period;
805         unsigned long long temp;
806
807         /*
808          * hpet_alloc can be called by platform dependent code.
809          * If platform dependent code has allocated the hpet that
810          * ACPI has also reported, then we catch it here.
811          */
812         if (hpet_is_known(hdp)) {
813                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
814                         __func__);
815                 return 0;
816         }
817
818         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
819                                       sizeof(struct hpet_dev));
820
821         hpetp = kzalloc(siz, GFP_KERNEL);
822
823         if (!hpetp)
824                 return -ENOMEM;
825
826         hpetp->hp_which = hpet_nhpet++;
827         hpetp->hp_hpet = hdp->hd_address;
828         hpetp->hp_hpet_phys = hdp->hd_phys_address;
829
830         hpetp->hp_ntimer = hdp->hd_nirqs;
831
832         for (i = 0; i < hdp->hd_nirqs; i++)
833                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
834
835         hpet = hpetp->hp_hpet;
836
837         cap = readq(&hpet->hpet_cap);
838
839         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
840
841         if (hpetp->hp_ntimer != ntimer) {
842                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
843                        " with number of timers\n");
844                 kfree(hpetp);
845                 return -ENODEV;
846         }
847
848         if (last)
849                 last->hp_next = hpetp;
850         else
851                 hpets = hpetp;
852
853         last = hpetp;
854
855         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
856                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
857         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
858         temp += period >> 1; /* round */
859         do_div(temp, period);
860         hpetp->hp_tick_freq = temp; /* ticks per second */
861
862         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
863                 hpetp->hp_which, hdp->hd_phys_address,
864                 hpetp->hp_ntimer > 1 ? "s" : "");
865         for (i = 0; i < hpetp->hp_ntimer; i++)
866                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
867         printk("\n");
868
869         printk(KERN_INFO "hpet%u: %u %d-bit timers, %Lu Hz\n",
870                hpetp->hp_which, hpetp->hp_ntimer,
871                cap & HPET_COUNTER_SIZE_MASK ? 64 : 32, hpetp->hp_tick_freq);
872
873         mcfg = readq(&hpet->hpet_config);
874         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
875                 write_counter(0L, &hpet->hpet_mc);
876                 mcfg |= HPET_ENABLE_CNF_MASK;
877                 writeq(mcfg, &hpet->hpet_config);
878         }
879
880         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
881                 struct hpet_timer __iomem *timer;
882
883                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
884
885                 devp->hd_hpets = hpetp;
886                 devp->hd_hpet = hpet;
887                 devp->hd_timer = timer;
888
889                 /*
890                  * If the timer was reserved by platform code,
891                  * then make timer unavailable for opens.
892                  */
893                 if (hdp->hd_state & (1 << i)) {
894                         devp->hd_flags = HPET_OPEN;
895                         continue;
896                 }
897
898                 init_waitqueue_head(&devp->hd_waitqueue);
899         }
900
901         hpetp->hp_delta = hpet_calibrate(hpetp);
902
903 /* This clocksource driver currently only works on ia64 */
904 #ifdef CONFIG_IA64
905         if (!hpet_clocksource) {
906                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
907                 CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
908                 clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
909                                                 clocksource_hpet.shift);
910                 clocksource_register(&clocksource_hpet);
911                 hpetp->hp_clocksource = &clocksource_hpet;
912                 hpet_clocksource = &clocksource_hpet;
913         }
914 #endif
915
916         return 0;
917 }
918
919 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
920 {
921         struct hpet_data *hdp;
922         acpi_status status;
923         struct acpi_resource_address64 addr;
924
925         hdp = data;
926
927         status = acpi_resource_to_address64(res, &addr);
928
929         if (ACPI_SUCCESS(status)) {
930                 hdp->hd_phys_address = addr.minimum;
931                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
932
933                 if (hpet_is_known(hdp)) {
934                         printk(KERN_DEBUG "%s: 0x%lx is busy\n",
935                                 __func__, hdp->hd_phys_address);
936                         iounmap(hdp->hd_address);
937                         return AE_ALREADY_EXISTS;
938                 }
939         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
940                 struct acpi_resource_fixed_memory32 *fixmem32;
941
942                 fixmem32 = &res->data.fixed_memory32;
943                 if (!fixmem32)
944                         return AE_NO_MEMORY;
945
946                 hdp->hd_phys_address = fixmem32->address;
947                 hdp->hd_address = ioremap(fixmem32->address,
948                                                 HPET_RANGE_SIZE);
949
950                 if (hpet_is_known(hdp)) {
951                         printk(KERN_DEBUG "%s: 0x%lx is busy\n",
952                                 __func__, hdp->hd_phys_address);
953                         iounmap(hdp->hd_address);
954                         return AE_ALREADY_EXISTS;
955                 }
956         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
957                 struct acpi_resource_extended_irq *irqp;
958                 int i, irq;
959
960                 irqp = &res->data.extended_irq;
961
962                 for (i = 0; i < irqp->interrupt_count; i++) {
963                         irq = acpi_register_gsi(irqp->interrupts[i],
964                                       irqp->triggering, irqp->polarity);
965                         if (irq < 0)
966                                 return AE_ERROR;
967
968                         hdp->hd_irq[hdp->hd_nirqs] = irq;
969                         hdp->hd_nirqs++;
970                 }
971         }
972
973         return AE_OK;
974 }
975
976 static int hpet_acpi_add(struct acpi_device *device)
977 {
978         acpi_status result;
979         struct hpet_data data;
980
981         memset(&data, 0, sizeof(data));
982
983         result =
984             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
985                                 hpet_resources, &data);
986
987         if (ACPI_FAILURE(result))
988                 return -ENODEV;
989
990         if (!data.hd_address || !data.hd_nirqs) {
991                 printk("%s: no address or irqs in _CRS\n", __func__);
992                 return -ENODEV;
993         }
994
995         return hpet_alloc(&data);
996 }
997
998 static int hpet_acpi_remove(struct acpi_device *device, int type)
999 {
1000         /* XXX need to unregister clocksource, dealloc mem, etc */
1001         return -EINVAL;
1002 }
1003
1004 static const struct acpi_device_id hpet_device_ids[] = {
1005         {"PNP0103", 0},
1006         {"", 0},
1007 };
1008 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
1009
1010 static struct acpi_driver hpet_acpi_driver = {
1011         .name = "hpet",
1012         .ids = hpet_device_ids,
1013         .ops = {
1014                 .add = hpet_acpi_add,
1015                 .remove = hpet_acpi_remove,
1016                 },
1017 };
1018
1019 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1020
1021 static int __init hpet_init(void)
1022 {
1023         int result;
1024
1025         result = misc_register(&hpet_misc);
1026         if (result < 0)
1027                 return -ENODEV;
1028
1029         sysctl_header = register_sysctl_table(dev_root);
1030
1031         result = acpi_bus_register_driver(&hpet_acpi_driver);
1032         if (result < 0) {
1033                 if (sysctl_header)
1034                         unregister_sysctl_table(sysctl_header);
1035                 misc_deregister(&hpet_misc);
1036                 return result;
1037         }
1038
1039         return 0;
1040 }
1041
1042 static void __exit hpet_exit(void)
1043 {
1044         acpi_bus_unregister_driver(&hpet_acpi_driver);
1045
1046         if (sysctl_header)
1047                 unregister_sysctl_table(sysctl_header);
1048         misc_deregister(&hpet_misc);
1049
1050         return;
1051 }
1052
1053 module_init(hpet_init);
1054 module_exit(hpet_exit);
1055 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1056 MODULE_LICENSE("GPL");