clocksource: pass clocksource to read() callback
[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/interrupt.h>
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/smp_lock.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/mm.h>
26 #include <linux/proc_fs.h>
27 #include <linux/spinlock.h>
28 #include <linux/sysctl.h>
29 #include <linux/wait.h>
30 #include <linux/bcd.h>
31 #include <linux/seq_file.h>
32 #include <linux/bitops.h>
33 #include <linux/clocksource.h>
34
35 #include <asm/current.h>
36 #include <asm/uaccess.h>
37 #include <asm/system.h>
38 #include <asm/io.h>
39 #include <asm/irq.h>
40 #include <asm/div64.h>
41
42 #include <linux/acpi.h>
43 #include <acpi/acpi_bus.h>
44 #include <linux/hpet.h>
45
46 /*
47  * The High Precision Event Timer driver.
48  * This driver is closely modelled after the rtc.c driver.
49  * http://www.intel.com/hardwaredesign/hpetspec_1.pdf
50  */
51 #define HPET_USER_FREQ  (64)
52 #define HPET_DRIFT      (500)
53
54 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
55
56
57 /* WARNING -- don't get confused.  These macros are never used
58  * to write the (single) counter, and rarely to read it.
59  * They're badly named; to fix, someday.
60  */
61 #if BITS_PER_LONG == 64
62 #define write_counter(V, MC)    writeq(V, MC)
63 #define read_counter(MC)        readq(MC)
64 #else
65 #define write_counter(V, MC)    writel(V, MC)
66 #define read_counter(MC)        readl(MC)
67 #endif
68
69 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
70
71 /* This clocksource driver currently only works on ia64 */
72 #ifdef CONFIG_IA64
73 static void __iomem *hpet_mctr;
74
75 static cycle_t read_hpet(struct clocksource *cs)
76 {
77         return (cycle_t)read_counter((void __iomem *)hpet_mctr);
78 }
79
80 static struct clocksource clocksource_hpet = {
81         .name           = "hpet",
82         .rating         = 250,
83         .read           = read_hpet,
84         .mask           = CLOCKSOURCE_MASK(64),
85         .mult           = 0, /* to be calculated */
86         .shift          = 10,
87         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
88 };
89 static struct clocksource *hpet_clocksource;
90 #endif
91
92 /* A lock for concurrent access by app and isr hpet activity. */
93 static DEFINE_SPINLOCK(hpet_lock);
94
95 #define HPET_DEV_NAME   (7)
96
97 struct hpet_dev {
98         struct hpets *hd_hpets;
99         struct hpet __iomem *hd_hpet;
100         struct hpet_timer __iomem *hd_timer;
101         unsigned long hd_ireqfreq;
102         unsigned long hd_irqdata;
103         wait_queue_head_t hd_waitqueue;
104         struct fasync_struct *hd_async_queue;
105         unsigned int hd_flags;
106         unsigned int hd_irq;
107         unsigned int hd_hdwirq;
108         char hd_name[HPET_DEV_NAME];
109 };
110
111 struct hpets {
112         struct hpets *hp_next;
113         struct hpet __iomem *hp_hpet;
114         unsigned long hp_hpet_phys;
115         struct clocksource *hp_clocksource;
116         unsigned long long hp_tick_freq;
117         unsigned long hp_delta;
118         unsigned int hp_ntimer;
119         unsigned int hp_which;
120         struct hpet_dev hp_dev[1];
121 };
122
123 static struct hpets *hpets;
124
125 #define HPET_OPEN               0x0001
126 #define HPET_IE                 0x0002  /* interrupt enabled */
127 #define HPET_PERIODIC           0x0004
128 #define HPET_SHARED_IRQ         0x0008
129
130
131 #ifndef readq
132 static inline unsigned long long readq(void __iomem *addr)
133 {
134         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
135 }
136 #endif
137
138 #ifndef writeq
139 static inline void writeq(unsigned long long v, void __iomem *addr)
140 {
141         writel(v & 0xffffffff, addr);
142         writel(v >> 32, addr + 4);
143 }
144 #endif
145
146 static irqreturn_t hpet_interrupt(int irq, void *data)
147 {
148         struct hpet_dev *devp;
149         unsigned long isr;
150
151         devp = data;
152         isr = 1 << (devp - devp->hd_hpets->hp_dev);
153
154         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
155             !(isr & readl(&devp->hd_hpet->hpet_isr)))
156                 return IRQ_NONE;
157
158         spin_lock(&hpet_lock);
159         devp->hd_irqdata++;
160
161         /*
162          * For non-periodic timers, increment the accumulator.
163          * This has the effect of treating non-periodic like periodic.
164          */
165         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
166                 unsigned long m, t;
167
168                 t = devp->hd_ireqfreq;
169                 m = read_counter(&devp->hd_hpet->hpet_mc);
170                 write_counter(t + m + devp->hd_hpets->hp_delta,
171                               &devp->hd_timer->hpet_compare);
172         }
173
174         if (devp->hd_flags & HPET_SHARED_IRQ)
175                 writel(isr, &devp->hd_hpet->hpet_isr);
176         spin_unlock(&hpet_lock);
177
178         wake_up_interruptible(&devp->hd_waitqueue);
179
180         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
181
182         return IRQ_HANDLED;
183 }
184
185 static void hpet_timer_set_irq(struct hpet_dev *devp)
186 {
187         unsigned long v;
188         int irq, gsi;
189         struct hpet_timer __iomem *timer;
190
191         spin_lock_irq(&hpet_lock);
192         if (devp->hd_hdwirq) {
193                 spin_unlock_irq(&hpet_lock);
194                 return;
195         }
196
197         timer = devp->hd_timer;
198
199         /* we prefer level triggered mode */
200         v = readl(&timer->hpet_config);
201         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
202                 v |= Tn_INT_TYPE_CNF_MASK;
203                 writel(v, &timer->hpet_config);
204         }
205         spin_unlock_irq(&hpet_lock);
206
207         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
208                                  Tn_INT_ROUTE_CAP_SHIFT;
209
210         /*
211          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
212          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
213          */
214         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
215                 v &= ~0xf3df;
216         else
217                 v &= ~0xffff;
218
219         for (irq = find_first_bit(&v, HPET_MAX_IRQ); irq < HPET_MAX_IRQ;
220                 irq = find_next_bit(&v, HPET_MAX_IRQ, 1 + irq)) {
221
222                 if (irq >= nr_irqs) {
223                         irq = HPET_MAX_IRQ;
224                         break;
225                 }
226
227                 gsi = acpi_register_gsi(irq, ACPI_LEVEL_SENSITIVE,
228                                         ACPI_ACTIVE_LOW);
229                 if (gsi > 0)
230                         break;
231
232                 /* FIXME: Setup interrupt source table */
233         }
234
235         if (irq < HPET_MAX_IRQ) {
236                 spin_lock_irq(&hpet_lock);
237                 v = readl(&timer->hpet_config);
238                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
239                 writel(v, &timer->hpet_config);
240                 devp->hd_hdwirq = gsi;
241                 spin_unlock_irq(&hpet_lock);
242         }
243         return;
244 }
245
246 static int hpet_open(struct inode *inode, struct file *file)
247 {
248         struct hpet_dev *devp;
249         struct hpets *hpetp;
250         int i;
251
252         if (file->f_mode & FMODE_WRITE)
253                 return -EINVAL;
254
255         lock_kernel();
256         spin_lock_irq(&hpet_lock);
257
258         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
259                 for (i = 0; i < hpetp->hp_ntimer; i++)
260                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
261                                 continue;
262                         else {
263                                 devp = &hpetp->hp_dev[i];
264                                 break;
265                         }
266
267         if (!devp) {
268                 spin_unlock_irq(&hpet_lock);
269                 unlock_kernel();
270                 return -EBUSY;
271         }
272
273         file->private_data = devp;
274         devp->hd_irqdata = 0;
275         devp->hd_flags |= HPET_OPEN;
276         spin_unlock_irq(&hpet_lock);
277         unlock_kernel();
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         file->private_data = NULL;
431         return 0;
432 }
433
434 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
435
436 static int
437 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
438            unsigned long arg)
439 {
440         struct hpet_dev *devp;
441
442         devp = file->private_data;
443         return hpet_ioctl_common(devp, cmd, arg, 0);
444 }
445
446 static int hpet_ioctl_ieon(struct hpet_dev *devp)
447 {
448         struct hpet_timer __iomem *timer;
449         struct hpet __iomem *hpet;
450         struct hpets *hpetp;
451         int irq;
452         unsigned long g, v, t, m;
453         unsigned long flags, isr;
454
455         timer = devp->hd_timer;
456         hpet = devp->hd_hpet;
457         hpetp = devp->hd_hpets;
458
459         if (!devp->hd_ireqfreq)
460                 return -EIO;
461
462         spin_lock_irq(&hpet_lock);
463
464         if (devp->hd_flags & HPET_IE) {
465                 spin_unlock_irq(&hpet_lock);
466                 return -EBUSY;
467         }
468
469         devp->hd_flags |= HPET_IE;
470
471         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
472                 devp->hd_flags |= HPET_SHARED_IRQ;
473         spin_unlock_irq(&hpet_lock);
474
475         irq = devp->hd_hdwirq;
476
477         if (irq) {
478                 unsigned long irq_flags;
479
480                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
481                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
482                                                 ? IRQF_SHARED : IRQF_DISABLED;
483                 if (request_irq(irq, hpet_interrupt, irq_flags,
484                                 devp->hd_name, (void *)devp)) {
485                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
486                         irq = 0;
487                 }
488         }
489
490         if (irq == 0) {
491                 spin_lock_irq(&hpet_lock);
492                 devp->hd_flags ^= HPET_IE;
493                 spin_unlock_irq(&hpet_lock);
494                 return -EIO;
495         }
496
497         devp->hd_irq = irq;
498         t = devp->hd_ireqfreq;
499         v = readq(&timer->hpet_config);
500
501         /* 64-bit comparators are not yet supported through the ioctls,
502          * so force this into 32-bit mode if it supports both modes
503          */
504         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
505
506         if (devp->hd_flags & HPET_PERIODIC) {
507                 write_counter(t, &timer->hpet_compare);
508                 g |= Tn_TYPE_CNF_MASK;
509                 v |= Tn_TYPE_CNF_MASK;
510                 writeq(v, &timer->hpet_config);
511                 v |= Tn_VAL_SET_CNF_MASK;
512                 writeq(v, &timer->hpet_config);
513                 local_irq_save(flags);
514
515                 /* NOTE:  what we modify here is a hidden accumulator
516                  * register supported by periodic-capable comparators.
517                  * We never want to modify the (single) counter; that
518                  * would affect all the comparators.
519                  */
520                 m = read_counter(&hpet->hpet_mc);
521                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
522         } else {
523                 local_irq_save(flags);
524                 m = read_counter(&hpet->hpet_mc);
525                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
526         }
527
528         if (devp->hd_flags & HPET_SHARED_IRQ) {
529                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
530                 writel(isr, &hpet->hpet_isr);
531         }
532         writeq(g, &timer->hpet_config);
533         local_irq_restore(flags);
534
535         return 0;
536 }
537
538 /* converts Hz to number of timer ticks */
539 static inline unsigned long hpet_time_div(struct hpets *hpets,
540                                           unsigned long dis)
541 {
542         unsigned long long m;
543
544         m = hpets->hp_tick_freq + (dis >> 1);
545         do_div(m, dis);
546         return (unsigned long)m;
547 }
548
549 static int
550 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
551 {
552         struct hpet_timer __iomem *timer;
553         struct hpet __iomem *hpet;
554         struct hpets *hpetp;
555         int err;
556         unsigned long v;
557
558         switch (cmd) {
559         case HPET_IE_OFF:
560         case HPET_INFO:
561         case HPET_EPI:
562         case HPET_DPI:
563         case HPET_IRQFREQ:
564                 timer = devp->hd_timer;
565                 hpet = devp->hd_hpet;
566                 hpetp = devp->hd_hpets;
567                 break;
568         case HPET_IE_ON:
569                 return hpet_ioctl_ieon(devp);
570         default:
571                 return -EINVAL;
572         }
573
574         err = 0;
575
576         switch (cmd) {
577         case HPET_IE_OFF:
578                 if ((devp->hd_flags & HPET_IE) == 0)
579                         break;
580                 v = readq(&timer->hpet_config);
581                 v &= ~Tn_INT_ENB_CNF_MASK;
582                 writeq(v, &timer->hpet_config);
583                 if (devp->hd_irq) {
584                         free_irq(devp->hd_irq, devp);
585                         devp->hd_irq = 0;
586                 }
587                 devp->hd_flags ^= HPET_IE;
588                 break;
589         case HPET_INFO:
590                 {
591                         struct hpet_info info;
592
593                         if (devp->hd_ireqfreq)
594                                 info.hi_ireqfreq =
595                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
596                         else
597                                 info.hi_ireqfreq = 0;
598                         info.hi_flags =
599                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
600                         info.hi_hpet = hpetp->hp_which;
601                         info.hi_timer = devp - hpetp->hp_dev;
602                         if (kernel)
603                                 memcpy((void *)arg, &info, sizeof(info));
604                         else
605                                 if (copy_to_user((void __user *)arg, &info,
606                                                  sizeof(info)))
607                                         err = -EFAULT;
608                         break;
609                 }
610         case HPET_EPI:
611                 v = readq(&timer->hpet_config);
612                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
613                         err = -ENXIO;
614                         break;
615                 }
616                 devp->hd_flags |= HPET_PERIODIC;
617                 break;
618         case HPET_DPI:
619                 v = readq(&timer->hpet_config);
620                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
621                         err = -ENXIO;
622                         break;
623                 }
624                 if (devp->hd_flags & HPET_PERIODIC &&
625                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
626                         v = readq(&timer->hpet_config);
627                         v ^= Tn_TYPE_CNF_MASK;
628                         writeq(v, &timer->hpet_config);
629                 }
630                 devp->hd_flags &= ~HPET_PERIODIC;
631                 break;
632         case HPET_IRQFREQ:
633                 if (!kernel && (arg > hpet_max_freq) &&
634                     !capable(CAP_SYS_RESOURCE)) {
635                         err = -EACCES;
636                         break;
637                 }
638
639                 if (!arg) {
640                         err = -EINVAL;
641                         break;
642                 }
643
644                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
645         }
646
647         return err;
648 }
649
650 static const struct file_operations hpet_fops = {
651         .owner = THIS_MODULE,
652         .llseek = no_llseek,
653         .read = hpet_read,
654         .poll = hpet_poll,
655         .ioctl = hpet_ioctl,
656         .open = hpet_open,
657         .release = hpet_release,
658         .fasync = hpet_fasync,
659         .mmap = hpet_mmap,
660 };
661
662 static int hpet_is_known(struct hpet_data *hdp)
663 {
664         struct hpets *hpetp;
665
666         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
667                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
668                         return 1;
669
670         return 0;
671 }
672
673 static ctl_table hpet_table[] = {
674         {
675          .ctl_name = CTL_UNNUMBERED,
676          .procname = "max-user-freq",
677          .data = &hpet_max_freq,
678          .maxlen = sizeof(int),
679          .mode = 0644,
680          .proc_handler = &proc_dointvec,
681          },
682         {.ctl_name = 0}
683 };
684
685 static ctl_table hpet_root[] = {
686         {
687          .ctl_name = CTL_UNNUMBERED,
688          .procname = "hpet",
689          .maxlen = 0,
690          .mode = 0555,
691          .child = hpet_table,
692          },
693         {.ctl_name = 0}
694 };
695
696 static ctl_table dev_root[] = {
697         {
698          .ctl_name = CTL_DEV,
699          .procname = "dev",
700          .maxlen = 0,
701          .mode = 0555,
702          .child = hpet_root,
703          },
704         {.ctl_name = 0}
705 };
706
707 static struct ctl_table_header *sysctl_header;
708
709 /*
710  * Adjustment for when arming the timer with
711  * initial conditions.  That is, main counter
712  * ticks expired before interrupts are enabled.
713  */
714 #define TICK_CALIBRATE  (1000UL)
715
716 static unsigned long __hpet_calibrate(struct hpets *hpetp)
717 {
718         struct hpet_timer __iomem *timer = NULL;
719         unsigned long t, m, count, i, flags, start;
720         struct hpet_dev *devp;
721         int j;
722         struct hpet __iomem *hpet;
723
724         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
725                 if ((devp->hd_flags & HPET_OPEN) == 0) {
726                         timer = devp->hd_timer;
727                         break;
728                 }
729
730         if (!timer)
731                 return 0;
732
733         hpet = hpetp->hp_hpet;
734         t = read_counter(&timer->hpet_compare);
735
736         i = 0;
737         count = hpet_time_div(hpetp, TICK_CALIBRATE);
738
739         local_irq_save(flags);
740
741         start = read_counter(&hpet->hpet_mc);
742
743         do {
744                 m = read_counter(&hpet->hpet_mc);
745                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
746         } while (i++, (m - start) < count);
747
748         local_irq_restore(flags);
749
750         return (m - start) / i;
751 }
752
753 static unsigned long hpet_calibrate(struct hpets *hpetp)
754 {
755         unsigned long ret = -1;
756         unsigned long tmp;
757
758         /*
759          * Try to calibrate until return value becomes stable small value.
760          * If SMI interruption occurs in calibration loop, the return value
761          * will be big. This avoids its impact.
762          */
763         for ( ; ; ) {
764                 tmp = __hpet_calibrate(hpetp);
765                 if (ret <= tmp)
766                         break;
767                 ret = tmp;
768         }
769
770         return ret;
771 }
772
773 int hpet_alloc(struct hpet_data *hdp)
774 {
775         u64 cap, mcfg;
776         struct hpet_dev *devp;
777         u32 i, ntimer;
778         struct hpets *hpetp;
779         size_t siz;
780         struct hpet __iomem *hpet;
781         static struct hpets *last = NULL;
782         unsigned long period;
783         unsigned long long temp;
784         u32 remainder;
785
786         /*
787          * hpet_alloc can be called by platform dependent code.
788          * If platform dependent code has allocated the hpet that
789          * ACPI has also reported, then we catch it here.
790          */
791         if (hpet_is_known(hdp)) {
792                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
793                         __func__);
794                 return 0;
795         }
796
797         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
798                                       sizeof(struct hpet_dev));
799
800         hpetp = kzalloc(siz, GFP_KERNEL);
801
802         if (!hpetp)
803                 return -ENOMEM;
804
805         hpetp->hp_which = hpet_nhpet++;
806         hpetp->hp_hpet = hdp->hd_address;
807         hpetp->hp_hpet_phys = hdp->hd_phys_address;
808
809         hpetp->hp_ntimer = hdp->hd_nirqs;
810
811         for (i = 0; i < hdp->hd_nirqs; i++)
812                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
813
814         hpet = hpetp->hp_hpet;
815
816         cap = readq(&hpet->hpet_cap);
817
818         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
819
820         if (hpetp->hp_ntimer != ntimer) {
821                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
822                        " with number of timers\n");
823                 kfree(hpetp);
824                 return -ENODEV;
825         }
826
827         if (last)
828                 last->hp_next = hpetp;
829         else
830                 hpets = hpetp;
831
832         last = hpetp;
833
834         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
835                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
836         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
837         temp += period >> 1; /* round */
838         do_div(temp, period);
839         hpetp->hp_tick_freq = temp; /* ticks per second */
840
841         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
842                 hpetp->hp_which, hdp->hd_phys_address,
843                 hpetp->hp_ntimer > 1 ? "s" : "");
844         for (i = 0; i < hpetp->hp_ntimer; i++)
845                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
846         printk("\n");
847
848         temp = hpetp->hp_tick_freq;
849         remainder = do_div(temp, 1000000);
850         printk(KERN_INFO
851                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
852                 hpetp->hp_which, hpetp->hp_ntimer,
853                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
854                 (unsigned) temp, remainder);
855
856         mcfg = readq(&hpet->hpet_config);
857         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
858                 write_counter(0L, &hpet->hpet_mc);
859                 mcfg |= HPET_ENABLE_CNF_MASK;
860                 writeq(mcfg, &hpet->hpet_config);
861         }
862
863         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
864                 struct hpet_timer __iomem *timer;
865
866                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
867
868                 devp->hd_hpets = hpetp;
869                 devp->hd_hpet = hpet;
870                 devp->hd_timer = timer;
871
872                 /*
873                  * If the timer was reserved by platform code,
874                  * then make timer unavailable for opens.
875                  */
876                 if (hdp->hd_state & (1 << i)) {
877                         devp->hd_flags = HPET_OPEN;
878                         continue;
879                 }
880
881                 init_waitqueue_head(&devp->hd_waitqueue);
882         }
883
884         hpetp->hp_delta = hpet_calibrate(hpetp);
885
886 /* This clocksource driver currently only works on ia64 */
887 #ifdef CONFIG_IA64
888         if (!hpet_clocksource) {
889                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
890                 CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
891                 clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
892                                                 clocksource_hpet.shift);
893                 clocksource_register(&clocksource_hpet);
894                 hpetp->hp_clocksource = &clocksource_hpet;
895                 hpet_clocksource = &clocksource_hpet;
896         }
897 #endif
898
899         return 0;
900 }
901
902 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
903 {
904         struct hpet_data *hdp;
905         acpi_status status;
906         struct acpi_resource_address64 addr;
907
908         hdp = data;
909
910         status = acpi_resource_to_address64(res, &addr);
911
912         if (ACPI_SUCCESS(status)) {
913                 hdp->hd_phys_address = addr.minimum;
914                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
915
916                 if (hpet_is_known(hdp)) {
917                         iounmap(hdp->hd_address);
918                         return AE_ALREADY_EXISTS;
919                 }
920         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
921                 struct acpi_resource_fixed_memory32 *fixmem32;
922
923                 fixmem32 = &res->data.fixed_memory32;
924                 if (!fixmem32)
925                         return AE_NO_MEMORY;
926
927                 hdp->hd_phys_address = fixmem32->address;
928                 hdp->hd_address = ioremap(fixmem32->address,
929                                                 HPET_RANGE_SIZE);
930
931                 if (hpet_is_known(hdp)) {
932                         iounmap(hdp->hd_address);
933                         return AE_ALREADY_EXISTS;
934                 }
935         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
936                 struct acpi_resource_extended_irq *irqp;
937                 int i, irq;
938
939                 irqp = &res->data.extended_irq;
940
941                 for (i = 0; i < irqp->interrupt_count; i++) {
942                         irq = acpi_register_gsi(irqp->interrupts[i],
943                                       irqp->triggering, irqp->polarity);
944                         if (irq < 0)
945                                 return AE_ERROR;
946
947                         hdp->hd_irq[hdp->hd_nirqs] = irq;
948                         hdp->hd_nirqs++;
949                 }
950         }
951
952         return AE_OK;
953 }
954
955 static int hpet_acpi_add(struct acpi_device *device)
956 {
957         acpi_status result;
958         struct hpet_data data;
959
960         memset(&data, 0, sizeof(data));
961
962         result =
963             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
964                                 hpet_resources, &data);
965
966         if (ACPI_FAILURE(result))
967                 return -ENODEV;
968
969         if (!data.hd_address || !data.hd_nirqs) {
970                 printk("%s: no address or irqs in _CRS\n", __func__);
971                 return -ENODEV;
972         }
973
974         return hpet_alloc(&data);
975 }
976
977 static int hpet_acpi_remove(struct acpi_device *device, int type)
978 {
979         /* XXX need to unregister clocksource, dealloc mem, etc */
980         return -EINVAL;
981 }
982
983 static const struct acpi_device_id hpet_device_ids[] = {
984         {"PNP0103", 0},
985         {"", 0},
986 };
987 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
988
989 static struct acpi_driver hpet_acpi_driver = {
990         .name = "hpet",
991         .ids = hpet_device_ids,
992         .ops = {
993                 .add = hpet_acpi_add,
994                 .remove = hpet_acpi_remove,
995                 },
996 };
997
998 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
999
1000 static int __init hpet_init(void)
1001 {
1002         int result;
1003
1004         result = misc_register(&hpet_misc);
1005         if (result < 0)
1006                 return -ENODEV;
1007
1008         sysctl_header = register_sysctl_table(dev_root);
1009
1010         result = acpi_bus_register_driver(&hpet_acpi_driver);
1011         if (result < 0) {
1012                 if (sysctl_header)
1013                         unregister_sysctl_table(sysctl_header);
1014                 misc_deregister(&hpet_misc);
1015                 return result;
1016         }
1017
1018         return 0;
1019 }
1020
1021 static void __exit hpet_exit(void)
1022 {
1023         acpi_bus_unregister_driver(&hpet_acpi_driver);
1024
1025         if (sysctl_header)
1026                 unregister_sysctl_table(sysctl_header);
1027         misc_deregister(&hpet_misc);
1028
1029         return;
1030 }
1031
1032 module_init(hpet_init);
1033 module_exit(hpet_exit);
1034 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1035 MODULE_LICENSE("GPL");