[PATCH] hpet: fix division by zero in HPET_INFO
[linux-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/config.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/kernel.h>
18 #include <linux/types.h>
19 #include <linux/miscdevice.h>
20 #include <linux/major.h>
21 #include <linux/ioport.h>
22 #include <linux/fcntl.h>
23 #include <linux/init.h>
24 #include <linux/poll.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
33 #include <asm/current.h>
34 #include <asm/uaccess.h>
35 #include <asm/system.h>
36 #include <asm/io.h>
37 #include <asm/irq.h>
38 #include <asm/div64.h>
39
40 #include <linux/acpi.h>
41 #include <acpi/acpi_bus.h>
42 #include <linux/hpet.h>
43
44 /*
45  * The High Precision Event Timer driver.
46  * This driver is closely modelled after the rtc.c driver.
47  * http://www.intel.com/hardwaredesign/hpetspec.htm
48  */
49 #define HPET_USER_FREQ  (64)
50 #define HPET_DRIFT      (500)
51
52 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
53
54 /* A lock for concurrent access by app and isr hpet activity. */
55 static DEFINE_SPINLOCK(hpet_lock);
56 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
57 static DEFINE_SPINLOCK(hpet_task_lock);
58
59 #define HPET_DEV_NAME   (7)
60
61 struct hpet_dev {
62         struct hpets *hd_hpets;
63         struct hpet __iomem *hd_hpet;
64         struct hpet_timer __iomem *hd_timer;
65         unsigned long hd_ireqfreq;
66         unsigned long hd_irqdata;
67         wait_queue_head_t hd_waitqueue;
68         struct fasync_struct *hd_async_queue;
69         struct hpet_task *hd_task;
70         unsigned int hd_flags;
71         unsigned int hd_irq;
72         unsigned int hd_hdwirq;
73         char hd_name[HPET_DEV_NAME];
74 };
75
76 struct hpets {
77         struct hpets *hp_next;
78         struct hpet __iomem *hp_hpet;
79         unsigned long hp_hpet_phys;
80         struct time_interpolator *hp_interpolator;
81         unsigned long long hp_tick_freq;
82         unsigned long hp_delta;
83         unsigned int hp_ntimer;
84         unsigned int hp_which;
85         struct hpet_dev hp_dev[1];
86 };
87
88 static struct hpets *hpets;
89
90 #define HPET_OPEN               0x0001
91 #define HPET_IE                 0x0002  /* interrupt enabled */
92 #define HPET_PERIODIC           0x0004
93 #define HPET_SHARED_IRQ         0x0008
94
95 #if BITS_PER_LONG == 64
96 #define write_counter(V, MC)    writeq(V, MC)
97 #define read_counter(MC)        readq(MC)
98 #else
99 #define write_counter(V, MC)    writel(V, MC)
100 #define read_counter(MC)        readl(MC)
101 #endif
102
103 #ifndef readq
104 static inline unsigned long long readq(void __iomem *addr)
105 {
106         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
107 }
108 #endif
109
110 #ifndef writeq
111 static inline void writeq(unsigned long long v, void __iomem *addr)
112 {
113         writel(v & 0xffffffff, addr);
114         writel(v >> 32, addr + 4);
115 }
116 #endif
117
118 static irqreturn_t hpet_interrupt(int irq, void *data, struct pt_regs *regs)
119 {
120         struct hpet_dev *devp;
121         unsigned long isr;
122
123         devp = data;
124         isr = 1 << (devp - devp->hd_hpets->hp_dev);
125
126         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
127             !(isr & readl(&devp->hd_hpet->hpet_isr)))
128                 return IRQ_NONE;
129
130         spin_lock(&hpet_lock);
131         devp->hd_irqdata++;
132
133         /*
134          * For non-periodic timers, increment the accumulator.
135          * This has the effect of treating non-periodic like periodic.
136          */
137         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
138                 unsigned long m, t;
139
140                 t = devp->hd_ireqfreq;
141                 m = read_counter(&devp->hd_hpet->hpet_mc);
142                 write_counter(t + m + devp->hd_hpets->hp_delta,
143                               &devp->hd_timer->hpet_compare);
144         }
145
146         if (devp->hd_flags & HPET_SHARED_IRQ)
147                 writel(isr, &devp->hd_hpet->hpet_isr);
148         spin_unlock(&hpet_lock);
149
150         spin_lock(&hpet_task_lock);
151         if (devp->hd_task)
152                 devp->hd_task->ht_func(devp->hd_task->ht_data);
153         spin_unlock(&hpet_task_lock);
154
155         wake_up_interruptible(&devp->hd_waitqueue);
156
157         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
158
159         return IRQ_HANDLED;
160 }
161
162 static int hpet_open(struct inode *inode, struct file *file)
163 {
164         struct hpet_dev *devp;
165         struct hpets *hpetp;
166         int i;
167
168         if (file->f_mode & FMODE_WRITE)
169                 return -EINVAL;
170
171         spin_lock_irq(&hpet_lock);
172
173         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
174                 for (i = 0; i < hpetp->hp_ntimer; i++)
175                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
176                             || hpetp->hp_dev[i].hd_task)
177                                 continue;
178                         else {
179                                 devp = &hpetp->hp_dev[i];
180                                 break;
181                         }
182
183         if (!devp) {
184                 spin_unlock_irq(&hpet_lock);
185                 return -EBUSY;
186         }
187
188         file->private_data = devp;
189         devp->hd_irqdata = 0;
190         devp->hd_flags |= HPET_OPEN;
191         spin_unlock_irq(&hpet_lock);
192
193         return 0;
194 }
195
196 static ssize_t
197 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
198 {
199         DECLARE_WAITQUEUE(wait, current);
200         unsigned long data;
201         ssize_t retval;
202         struct hpet_dev *devp;
203
204         devp = file->private_data;
205         if (!devp->hd_ireqfreq)
206                 return -EIO;
207
208         if (count < sizeof(unsigned long))
209                 return -EINVAL;
210
211         add_wait_queue(&devp->hd_waitqueue, &wait);
212
213         for ( ; ; ) {
214                 set_current_state(TASK_INTERRUPTIBLE);
215
216                 spin_lock_irq(&hpet_lock);
217                 data = devp->hd_irqdata;
218                 devp->hd_irqdata = 0;
219                 spin_unlock_irq(&hpet_lock);
220
221                 if (data)
222                         break;
223                 else if (file->f_flags & O_NONBLOCK) {
224                         retval = -EAGAIN;
225                         goto out;
226                 } else if (signal_pending(current)) {
227                         retval = -ERESTARTSYS;
228                         goto out;
229                 }
230                 schedule();
231         }
232
233         retval = put_user(data, (unsigned long __user *)buf);
234         if (!retval)
235                 retval = sizeof(unsigned long);
236 out:
237         __set_current_state(TASK_RUNNING);
238         remove_wait_queue(&devp->hd_waitqueue, &wait);
239
240         return retval;
241 }
242
243 static unsigned int hpet_poll(struct file *file, poll_table * wait)
244 {
245         unsigned long v;
246         struct hpet_dev *devp;
247
248         devp = file->private_data;
249
250         if (!devp->hd_ireqfreq)
251                 return 0;
252
253         poll_wait(file, &devp->hd_waitqueue, wait);
254
255         spin_lock_irq(&hpet_lock);
256         v = devp->hd_irqdata;
257         spin_unlock_irq(&hpet_lock);
258
259         if (v != 0)
260                 return POLLIN | POLLRDNORM;
261
262         return 0;
263 }
264
265 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
266 {
267 #ifdef  CONFIG_HPET_MMAP
268         struct hpet_dev *devp;
269         unsigned long addr;
270
271         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
272                 return -EINVAL;
273
274         devp = file->private_data;
275         addr = devp->hd_hpets->hp_hpet_phys;
276
277         if (addr & (PAGE_SIZE - 1))
278                 return -ENOSYS;
279
280         vma->vm_flags |= VM_IO;
281         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
282
283         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
284                                         PAGE_SIZE, vma->vm_page_prot)) {
285                 printk(KERN_ERR "remap_pfn_range failed in hpet.c\n");
286                 return -EAGAIN;
287         }
288
289         return 0;
290 #else
291         return -ENOSYS;
292 #endif
293 }
294
295 static int hpet_fasync(int fd, struct file *file, int on)
296 {
297         struct hpet_dev *devp;
298
299         devp = file->private_data;
300
301         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
302                 return 0;
303         else
304                 return -EIO;
305 }
306
307 static int hpet_release(struct inode *inode, struct file *file)
308 {
309         struct hpet_dev *devp;
310         struct hpet_timer __iomem *timer;
311         int irq = 0;
312
313         devp = file->private_data;
314         timer = devp->hd_timer;
315
316         spin_lock_irq(&hpet_lock);
317
318         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
319                &timer->hpet_config);
320
321         irq = devp->hd_irq;
322         devp->hd_irq = 0;
323
324         devp->hd_ireqfreq = 0;
325
326         if (devp->hd_flags & HPET_PERIODIC
327             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
328                 unsigned long v;
329
330                 v = readq(&timer->hpet_config);
331                 v ^= Tn_TYPE_CNF_MASK;
332                 writeq(v, &timer->hpet_config);
333         }
334
335         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
336         spin_unlock_irq(&hpet_lock);
337
338         if (irq)
339                 free_irq(irq, devp);
340
341         if (file->f_flags & FASYNC)
342                 hpet_fasync(-1, file, 0);
343
344         file->private_data = NULL;
345         return 0;
346 }
347
348 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
349
350 static int
351 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
352            unsigned long arg)
353 {
354         struct hpet_dev *devp;
355
356         devp = file->private_data;
357         return hpet_ioctl_common(devp, cmd, arg, 0);
358 }
359
360 static int hpet_ioctl_ieon(struct hpet_dev *devp)
361 {
362         struct hpet_timer __iomem *timer;
363         struct hpet __iomem *hpet;
364         struct hpets *hpetp;
365         int irq;
366         unsigned long g, v, t, m;
367         unsigned long flags, isr;
368
369         timer = devp->hd_timer;
370         hpet = devp->hd_hpet;
371         hpetp = devp->hd_hpets;
372
373         if (!devp->hd_ireqfreq)
374                 return -EIO;
375
376         spin_lock_irq(&hpet_lock);
377
378         if (devp->hd_flags & HPET_IE) {
379                 spin_unlock_irq(&hpet_lock);
380                 return -EBUSY;
381         }
382
383         devp->hd_flags |= HPET_IE;
384
385         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
386                 devp->hd_flags |= HPET_SHARED_IRQ;
387         spin_unlock_irq(&hpet_lock);
388
389         irq = devp->hd_hdwirq;
390
391         if (irq) {
392                 unsigned long irq_flags;
393
394                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
395                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
396                                                 ? SA_SHIRQ : SA_INTERRUPT;
397                 if (request_irq(irq, hpet_interrupt, irq_flags,
398                                 devp->hd_name, (void *)devp)) {
399                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
400                         irq = 0;
401                 }
402         }
403
404         if (irq == 0) {
405                 spin_lock_irq(&hpet_lock);
406                 devp->hd_flags ^= HPET_IE;
407                 spin_unlock_irq(&hpet_lock);
408                 return -EIO;
409         }
410
411         devp->hd_irq = irq;
412         t = devp->hd_ireqfreq;
413         v = readq(&timer->hpet_config);
414         g = v | Tn_INT_ENB_CNF_MASK;
415
416         if (devp->hd_flags & HPET_PERIODIC) {
417                 write_counter(t, &timer->hpet_compare);
418                 g |= Tn_TYPE_CNF_MASK;
419                 v |= Tn_TYPE_CNF_MASK;
420                 writeq(v, &timer->hpet_config);
421                 v |= Tn_VAL_SET_CNF_MASK;
422                 writeq(v, &timer->hpet_config);
423                 local_irq_save(flags);
424                 m = read_counter(&hpet->hpet_mc);
425                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
426         } else {
427                 local_irq_save(flags);
428                 m = read_counter(&hpet->hpet_mc);
429                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
430         }
431
432         if (devp->hd_flags & HPET_SHARED_IRQ) {
433                 isr = 1 << (devp - hpets->hp_dev);
434                 writel(isr, &hpet->hpet_isr);
435         }
436         writeq(g, &timer->hpet_config);
437         local_irq_restore(flags);
438
439         return 0;
440 }
441
442 /* converts Hz to number of timer ticks */
443 static inline unsigned long hpet_time_div(struct hpets *hpets,
444                                           unsigned long dis)
445 {
446         unsigned long long m;
447
448         m = hpets->hp_tick_freq + (dis >> 1);
449         do_div(m, dis);
450         return (unsigned long)m;
451 }
452
453 static int
454 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
455 {
456         struct hpet_timer __iomem *timer;
457         struct hpet __iomem *hpet;
458         struct hpets *hpetp;
459         int err;
460         unsigned long v;
461
462         switch (cmd) {
463         case HPET_IE_OFF:
464         case HPET_INFO:
465         case HPET_EPI:
466         case HPET_DPI:
467         case HPET_IRQFREQ:
468                 timer = devp->hd_timer;
469                 hpet = devp->hd_hpet;
470                 hpetp = devp->hd_hpets;
471                 break;
472         case HPET_IE_ON:
473                 return hpet_ioctl_ieon(devp);
474         default:
475                 return -EINVAL;
476         }
477
478         err = 0;
479
480         switch (cmd) {
481         case HPET_IE_OFF:
482                 if ((devp->hd_flags & HPET_IE) == 0)
483                         break;
484                 v = readq(&timer->hpet_config);
485                 v &= ~Tn_INT_ENB_CNF_MASK;
486                 writeq(v, &timer->hpet_config);
487                 if (devp->hd_irq) {
488                         free_irq(devp->hd_irq, devp);
489                         devp->hd_irq = 0;
490                 }
491                 devp->hd_flags ^= HPET_IE;
492                 break;
493         case HPET_INFO:
494                 {
495                         struct hpet_info info;
496
497                         if (devp->hd_ireqfreq)
498                                 info.hi_ireqfreq =
499                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
500                         else
501                                 info.hi_ireqfreq = 0;
502                         info.hi_flags =
503                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
504                         info.hi_hpet = devp->hd_hpets->hp_which;
505                         info.hi_timer = devp - devp->hd_hpets->hp_dev;
506                         if (kernel)
507                                 memcpy((void *)arg, &info, sizeof(info));
508                         else
509                                 if (copy_to_user((void __user *)arg, &info,
510                                                  sizeof(info)))
511                                         err = -EFAULT;
512                         break;
513                 }
514         case HPET_EPI:
515                 v = readq(&timer->hpet_config);
516                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
517                         err = -ENXIO;
518                         break;
519                 }
520                 devp->hd_flags |= HPET_PERIODIC;
521                 break;
522         case HPET_DPI:
523                 v = readq(&timer->hpet_config);
524                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
525                         err = -ENXIO;
526                         break;
527                 }
528                 if (devp->hd_flags & HPET_PERIODIC &&
529                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
530                         v = readq(&timer->hpet_config);
531                         v ^= Tn_TYPE_CNF_MASK;
532                         writeq(v, &timer->hpet_config);
533                 }
534                 devp->hd_flags &= ~HPET_PERIODIC;
535                 break;
536         case HPET_IRQFREQ:
537                 if (!kernel && (arg > hpet_max_freq) &&
538                     !capable(CAP_SYS_RESOURCE)) {
539                         err = -EACCES;
540                         break;
541                 }
542
543                 if (!arg) {
544                         err = -EINVAL;
545                         break;
546                 }
547
548                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
549         }
550
551         return err;
552 }
553
554 static struct file_operations hpet_fops = {
555         .owner = THIS_MODULE,
556         .llseek = no_llseek,
557         .read = hpet_read,
558         .poll = hpet_poll,
559         .ioctl = hpet_ioctl,
560         .open = hpet_open,
561         .release = hpet_release,
562         .fasync = hpet_fasync,
563         .mmap = hpet_mmap,
564 };
565
566 EXPORT_SYMBOL(hpet_alloc);
567 EXPORT_SYMBOL(hpet_register);
568 EXPORT_SYMBOL(hpet_unregister);
569 EXPORT_SYMBOL(hpet_control);
570
571 int hpet_register(struct hpet_task *tp, int periodic)
572 {
573         unsigned int i;
574         u64 mask;
575         struct hpet_timer __iomem *timer;
576         struct hpet_dev *devp;
577         struct hpets *hpetp;
578
579         switch (periodic) {
580         case 1:
581                 mask = Tn_PER_INT_CAP_MASK;
582                 break;
583         case 0:
584                 mask = 0;
585                 break;
586         default:
587                 return -EINVAL;
588         }
589
590         spin_lock_irq(&hpet_task_lock);
591         spin_lock(&hpet_lock);
592
593         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
594                 for (timer = hpetp->hp_hpet->hpet_timers, i = 0;
595                      i < hpetp->hp_ntimer; i++, timer++) {
596                         if ((readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK)
597                             != mask)
598                                 continue;
599
600                         devp = &hpetp->hp_dev[i];
601
602                         if (devp->hd_flags & HPET_OPEN || devp->hd_task) {
603                                 devp = NULL;
604                                 continue;
605                         }
606
607                         tp->ht_opaque = devp;
608                         devp->hd_task = tp;
609                         break;
610                 }
611
612         spin_unlock(&hpet_lock);
613         spin_unlock_irq(&hpet_task_lock);
614
615         if (tp->ht_opaque)
616                 return 0;
617         else
618                 return -EBUSY;
619 }
620
621 static inline int hpet_tpcheck(struct hpet_task *tp)
622 {
623         struct hpet_dev *devp;
624         struct hpets *hpetp;
625
626         devp = tp->ht_opaque;
627
628         if (!devp)
629                 return -ENXIO;
630
631         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
632                 if (devp >= hpetp->hp_dev
633                     && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
634                     && devp->hd_hpet == hpetp->hp_hpet)
635                         return 0;
636
637         return -ENXIO;
638 }
639
640 int hpet_unregister(struct hpet_task *tp)
641 {
642         struct hpet_dev *devp;
643         struct hpet_timer __iomem *timer;
644         int err;
645
646         if ((err = hpet_tpcheck(tp)))
647                 return err;
648
649         spin_lock_irq(&hpet_task_lock);
650         spin_lock(&hpet_lock);
651
652         devp = tp->ht_opaque;
653         if (devp->hd_task != tp) {
654                 spin_unlock(&hpet_lock);
655                 spin_unlock_irq(&hpet_task_lock);
656                 return -ENXIO;
657         }
658
659         timer = devp->hd_timer;
660         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
661                &timer->hpet_config);
662         devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
663         devp->hd_task = NULL;
664         spin_unlock(&hpet_lock);
665         spin_unlock_irq(&hpet_task_lock);
666
667         return 0;
668 }
669
670 int hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
671 {
672         struct hpet_dev *devp;
673         int err;
674
675         if ((err = hpet_tpcheck(tp)))
676                 return err;
677
678         spin_lock_irq(&hpet_lock);
679         devp = tp->ht_opaque;
680         if (devp->hd_task != tp) {
681                 spin_unlock_irq(&hpet_lock);
682                 return -ENXIO;
683         }
684         spin_unlock_irq(&hpet_lock);
685         return hpet_ioctl_common(devp, cmd, arg, 1);
686 }
687
688 static ctl_table hpet_table[] = {
689         {
690          .ctl_name = 1,
691          .procname = "max-user-freq",
692          .data = &hpet_max_freq,
693          .maxlen = sizeof(int),
694          .mode = 0644,
695          .proc_handler = &proc_dointvec,
696          },
697         {.ctl_name = 0}
698 };
699
700 static ctl_table hpet_root[] = {
701         {
702          .ctl_name = 1,
703          .procname = "hpet",
704          .maxlen = 0,
705          .mode = 0555,
706          .child = hpet_table,
707          },
708         {.ctl_name = 0}
709 };
710
711 static ctl_table dev_root[] = {
712         {
713          .ctl_name = CTL_DEV,
714          .procname = "dev",
715          .maxlen = 0,
716          .mode = 0555,
717          .child = hpet_root,
718          },
719         {.ctl_name = 0}
720 };
721
722 static struct ctl_table_header *sysctl_header;
723
724 static void hpet_register_interpolator(struct hpets *hpetp)
725 {
726 #ifdef  CONFIG_TIME_INTERPOLATION
727         struct time_interpolator *ti;
728
729         ti = kmalloc(sizeof(*ti), GFP_KERNEL);
730         if (!ti)
731                 return;
732
733         memset(ti, 0, sizeof(*ti));
734         ti->source = TIME_SOURCE_MMIO64;
735         ti->shift = 10;
736         ti->addr = &hpetp->hp_hpet->hpet_mc;
737         ti->frequency = hpetp->hp_tick_freq;
738         ti->drift = HPET_DRIFT;
739         ti->mask = -1;
740
741         hpetp->hp_interpolator = ti;
742         register_time_interpolator(ti);
743 #endif
744 }
745
746 /*
747  * Adjustment for when arming the timer with
748  * initial conditions.  That is, main counter
749  * ticks expired before interrupts are enabled.
750  */
751 #define TICK_CALIBRATE  (1000UL)
752
753 static unsigned long hpet_calibrate(struct hpets *hpetp)
754 {
755         struct hpet_timer __iomem *timer = NULL;
756         unsigned long t, m, count, i, flags, start;
757         struct hpet_dev *devp;
758         int j;
759         struct hpet __iomem *hpet;
760
761         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
762                 if ((devp->hd_flags & HPET_OPEN) == 0) {
763                         timer = devp->hd_timer;
764                         break;
765                 }
766
767         if (!timer)
768                 return 0;
769
770         hpet = hpets->hp_hpet;
771         t = read_counter(&timer->hpet_compare);
772
773         i = 0;
774         count = hpet_time_div(hpetp, TICK_CALIBRATE);
775
776         local_irq_save(flags);
777
778         start = read_counter(&hpet->hpet_mc);
779
780         do {
781                 m = read_counter(&hpet->hpet_mc);
782                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
783         } while (i++, (m - start) < count);
784
785         local_irq_restore(flags);
786
787         return (m - start) / i;
788 }
789
790 int hpet_alloc(struct hpet_data *hdp)
791 {
792         u64 cap, mcfg;
793         struct hpet_dev *devp;
794         u32 i, ntimer;
795         struct hpets *hpetp;
796         size_t siz;
797         struct hpet __iomem *hpet;
798         static struct hpets *last = (struct hpets *)0;
799         unsigned long ns, period;
800         unsigned long long temp;
801
802         /*
803          * hpet_alloc can be called by platform dependent code.
804          * if platform dependent code has allocated the hpet
805          * ACPI also reports hpet, then we catch it here.
806          */
807         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
808                 if (hpetp->hp_hpet == hdp->hd_address)
809                         return 0;
810
811         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
812                                       sizeof(struct hpet_dev));
813
814         hpetp = kmalloc(siz, GFP_KERNEL);
815
816         if (!hpetp)
817                 return -ENOMEM;
818
819         memset(hpetp, 0, siz);
820
821         hpetp->hp_which = hpet_nhpet++;
822         hpetp->hp_hpet = hdp->hd_address;
823         hpetp->hp_hpet_phys = hdp->hd_phys_address;
824
825         hpetp->hp_ntimer = hdp->hd_nirqs;
826
827         for (i = 0; i < hdp->hd_nirqs; i++)
828                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
829
830         hpet = hpetp->hp_hpet;
831
832         cap = readq(&hpet->hpet_cap);
833
834         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
835
836         if (hpetp->hp_ntimer != ntimer) {
837                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
838                        " with number of timers\n");
839                 kfree(hpetp);
840                 return -ENODEV;
841         }
842
843         if (last)
844                 last->hp_next = hpetp;
845         else
846                 hpets = hpetp;
847
848         last = hpetp;
849
850         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
851                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
852         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
853         temp += period >> 1; /* round */
854         do_div(temp, period);
855         hpetp->hp_tick_freq = temp; /* ticks per second */
856
857         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
858                 hpetp->hp_which, hdp->hd_phys_address,
859                 hpetp->hp_ntimer > 1 ? "s" : "");
860         for (i = 0; i < hpetp->hp_ntimer; i++)
861                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
862         printk("\n");
863
864         ns = period / 1000000;  /* convert to nanoseconds, 10^-9 */
865         printk(KERN_INFO "hpet%d: %ldns tick, %d %d-bit timers\n",
866                 hpetp->hp_which, ns, hpetp->hp_ntimer,
867                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32);
868
869         mcfg = readq(&hpet->hpet_config);
870         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
871                 write_counter(0L, &hpet->hpet_mc);
872                 mcfg |= HPET_ENABLE_CNF_MASK;
873                 writeq(mcfg, &hpet->hpet_config);
874         }
875
876         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
877                 struct hpet_timer __iomem *timer;
878
879                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
880
881                 devp->hd_hpets = hpetp;
882                 devp->hd_hpet = hpet;
883                 devp->hd_timer = timer;
884
885                 /*
886                  * If the timer was reserved by platform code,
887                  * then make timer unavailable for opens.
888                  */
889                 if (hdp->hd_state & (1 << i)) {
890                         devp->hd_flags = HPET_OPEN;
891                         continue;
892                 }
893
894                 init_waitqueue_head(&devp->hd_waitqueue);
895         }
896
897         hpetp->hp_delta = hpet_calibrate(hpetp);
898         hpet_register_interpolator(hpetp);
899
900         return 0;
901 }
902
903 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
904 {
905         struct hpet_data *hdp;
906         acpi_status status;
907         struct acpi_resource_address64 addr;
908         struct hpets *hpetp;
909
910         hdp = data;
911
912         status = acpi_resource_to_address64(res, &addr);
913
914         if (ACPI_SUCCESS(status)) {
915                 unsigned long size;
916
917                 size = addr.max_address_range - addr.min_address_range + 1;
918                 hdp->hd_phys_address = addr.min_address_range;
919                 hdp->hd_address = ioremap(addr.min_address_range, size);
920
921                 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
922                         if (hpetp->hp_hpet == hdp->hd_address)
923                                 return -EBUSY;
924         } else if (res->id == ACPI_RSTYPE_EXT_IRQ) {
925                 struct acpi_resource_ext_irq *irqp;
926                 int i;
927
928                 irqp = &res->data.extended_irq;
929
930                 if (irqp->number_of_interrupts > 0) {
931                         hdp->hd_nirqs = irqp->number_of_interrupts;
932
933                         for (i = 0; i < hdp->hd_nirqs; i++) {
934                                 int rc =
935                                     acpi_register_gsi(irqp->interrupts[i],
936                                                       irqp->edge_level,
937                                                       irqp->active_high_low);
938                                 if (rc < 0)
939                                         return AE_ERROR;
940                                 hdp->hd_irq[i] = rc;
941                         }
942                 }
943         }
944
945         return AE_OK;
946 }
947
948 static int hpet_acpi_add(struct acpi_device *device)
949 {
950         acpi_status result;
951         struct hpet_data data;
952
953         memset(&data, 0, sizeof(data));
954
955         result =
956             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
957                                 hpet_resources, &data);
958
959         if (ACPI_FAILURE(result))
960                 return -ENODEV;
961
962         if (!data.hd_address || !data.hd_nirqs) {
963                 printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
964                 return -ENODEV;
965         }
966
967         return hpet_alloc(&data);
968 }
969
970 static int hpet_acpi_remove(struct acpi_device *device, int type)
971 {
972         /* XXX need to unregister interpolator, dealloc mem, etc */
973         return -EINVAL;
974 }
975
976 static struct acpi_driver hpet_acpi_driver = {
977         .name = "hpet",
978         .ids = "PNP0103",
979         .ops = {
980                 .add = hpet_acpi_add,
981                 .remove = hpet_acpi_remove,
982                 },
983 };
984
985 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
986
987 static int __init hpet_init(void)
988 {
989         int result;
990
991         result = misc_register(&hpet_misc);
992         if (result < 0)
993                 return -ENODEV;
994
995         sysctl_header = register_sysctl_table(dev_root, 0);
996
997         result = acpi_bus_register_driver(&hpet_acpi_driver);
998         if (result < 0) {
999                 if (sysctl_header)
1000                         unregister_sysctl_table(sysctl_header);
1001                 misc_deregister(&hpet_misc);
1002                 return result;
1003         }
1004
1005         return 0;
1006 }
1007
1008 static void __exit hpet_exit(void)
1009 {
1010         acpi_bus_unregister_driver(&hpet_acpi_driver);
1011
1012         if (sysctl_header)
1013                 unregister_sysctl_table(sysctl_header);
1014         misc_deregister(&hpet_misc);
1015
1016         return;
1017 }
1018
1019 module_init(hpet_init);
1020 module_exit(hpet_exit);
1021 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1022 MODULE_LICENSE("GPL");