[ARM] mmp2: add support for board IRQs
[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_timer->hpet_compare);
170                 write_counter(t + m, &devp->hd_timer->hpet_compare);
171         }
172
173         if (devp->hd_flags & HPET_SHARED_IRQ)
174                 writel(isr, &devp->hd_hpet->hpet_isr);
175         spin_unlock(&hpet_lock);
176
177         wake_up_interruptible(&devp->hd_waitqueue);
178
179         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
180
181         return IRQ_HANDLED;
182 }
183
184 static void hpet_timer_set_irq(struct hpet_dev *devp)
185 {
186         unsigned long v;
187         int irq, gsi;
188         struct hpet_timer __iomem *timer;
189
190         spin_lock_irq(&hpet_lock);
191         if (devp->hd_hdwirq) {
192                 spin_unlock_irq(&hpet_lock);
193                 return;
194         }
195
196         timer = devp->hd_timer;
197
198         /* we prefer level triggered mode */
199         v = readl(&timer->hpet_config);
200         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
201                 v |= Tn_INT_TYPE_CNF_MASK;
202                 writel(v, &timer->hpet_config);
203         }
204         spin_unlock_irq(&hpet_lock);
205
206         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
207                                  Tn_INT_ROUTE_CAP_SHIFT;
208
209         /*
210          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
211          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
212          */
213         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
214                 v &= ~0xf3df;
215         else
216                 v &= ~0xffff;
217
218         for (irq = find_first_bit(&v, HPET_MAX_IRQ); irq < HPET_MAX_IRQ;
219                 irq = find_next_bit(&v, HPET_MAX_IRQ, 1 + irq)) {
220
221                 if (irq >= nr_irqs) {
222                         irq = HPET_MAX_IRQ;
223                         break;
224                 }
225
226                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
227                                         ACPI_ACTIVE_LOW);
228                 if (gsi > 0)
229                         break;
230
231                 /* FIXME: Setup interrupt source table */
232         }
233
234         if (irq < HPET_MAX_IRQ) {
235                 spin_lock_irq(&hpet_lock);
236                 v = readl(&timer->hpet_config);
237                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
238                 writel(v, &timer->hpet_config);
239                 devp->hd_hdwirq = gsi;
240                 spin_unlock_irq(&hpet_lock);
241         }
242         return;
243 }
244
245 static int hpet_open(struct inode *inode, struct file *file)
246 {
247         struct hpet_dev *devp;
248         struct hpets *hpetp;
249         int i;
250
251         if (file->f_mode & FMODE_WRITE)
252                 return -EINVAL;
253
254         lock_kernel();
255         spin_lock_irq(&hpet_lock);
256
257         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
258                 for (i = 0; i < hpetp->hp_ntimer; i++)
259                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
260                                 continue;
261                         else {
262                                 devp = &hpetp->hp_dev[i];
263                                 break;
264                         }
265
266         if (!devp) {
267                 spin_unlock_irq(&hpet_lock);
268                 unlock_kernel();
269                 return -EBUSY;
270         }
271
272         file->private_data = devp;
273         devp->hd_irqdata = 0;
274         devp->hd_flags |= HPET_OPEN;
275         spin_unlock_irq(&hpet_lock);
276         unlock_kernel();
277
278         hpet_timer_set_irq(devp);
279
280         return 0;
281 }
282
283 static ssize_t
284 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
285 {
286         DECLARE_WAITQUEUE(wait, current);
287         unsigned long data;
288         ssize_t retval;
289         struct hpet_dev *devp;
290
291         devp = file->private_data;
292         if (!devp->hd_ireqfreq)
293                 return -EIO;
294
295         if (count < sizeof(unsigned long))
296                 return -EINVAL;
297
298         add_wait_queue(&devp->hd_waitqueue, &wait);
299
300         for ( ; ; ) {
301                 set_current_state(TASK_INTERRUPTIBLE);
302
303                 spin_lock_irq(&hpet_lock);
304                 data = devp->hd_irqdata;
305                 devp->hd_irqdata = 0;
306                 spin_unlock_irq(&hpet_lock);
307
308                 if (data)
309                         break;
310                 else if (file->f_flags & O_NONBLOCK) {
311                         retval = -EAGAIN;
312                         goto out;
313                 } else if (signal_pending(current)) {
314                         retval = -ERESTARTSYS;
315                         goto out;
316                 }
317                 schedule();
318         }
319
320         retval = put_user(data, (unsigned long __user *)buf);
321         if (!retval)
322                 retval = sizeof(unsigned long);
323 out:
324         __set_current_state(TASK_RUNNING);
325         remove_wait_queue(&devp->hd_waitqueue, &wait);
326
327         return retval;
328 }
329
330 static unsigned int hpet_poll(struct file *file, poll_table * wait)
331 {
332         unsigned long v;
333         struct hpet_dev *devp;
334
335         devp = file->private_data;
336
337         if (!devp->hd_ireqfreq)
338                 return 0;
339
340         poll_wait(file, &devp->hd_waitqueue, wait);
341
342         spin_lock_irq(&hpet_lock);
343         v = devp->hd_irqdata;
344         spin_unlock_irq(&hpet_lock);
345
346         if (v != 0)
347                 return POLLIN | POLLRDNORM;
348
349         return 0;
350 }
351
352 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
353 {
354 #ifdef  CONFIG_HPET_MMAP
355         struct hpet_dev *devp;
356         unsigned long addr;
357
358         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
359                 return -EINVAL;
360
361         devp = file->private_data;
362         addr = devp->hd_hpets->hp_hpet_phys;
363
364         if (addr & (PAGE_SIZE - 1))
365                 return -ENOSYS;
366
367         vma->vm_flags |= VM_IO;
368         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
369
370         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
371                                         PAGE_SIZE, vma->vm_page_prot)) {
372                 printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
373                         __func__);
374                 return -EAGAIN;
375         }
376
377         return 0;
378 #else
379         return -ENOSYS;
380 #endif
381 }
382
383 static int hpet_fasync(int fd, struct file *file, int on)
384 {
385         struct hpet_dev *devp;
386
387         devp = file->private_data;
388
389         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
390                 return 0;
391         else
392                 return -EIO;
393 }
394
395 static int hpet_release(struct inode *inode, struct file *file)
396 {
397         struct hpet_dev *devp;
398         struct hpet_timer __iomem *timer;
399         int irq = 0;
400
401         devp = file->private_data;
402         timer = devp->hd_timer;
403
404         spin_lock_irq(&hpet_lock);
405
406         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
407                &timer->hpet_config);
408
409         irq = devp->hd_irq;
410         devp->hd_irq = 0;
411
412         devp->hd_ireqfreq = 0;
413
414         if (devp->hd_flags & HPET_PERIODIC
415             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
416                 unsigned long v;
417
418                 v = readq(&timer->hpet_config);
419                 v ^= Tn_TYPE_CNF_MASK;
420                 writeq(v, &timer->hpet_config);
421         }
422
423         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
424         spin_unlock_irq(&hpet_lock);
425
426         if (irq)
427                 free_irq(irq, devp);
428
429         file->private_data = NULL;
430         return 0;
431 }
432
433 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
434
435 static int
436 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
437            unsigned long arg)
438 {
439         struct hpet_dev *devp;
440
441         devp = file->private_data;
442         return hpet_ioctl_common(devp, cmd, arg, 0);
443 }
444
445 static int hpet_ioctl_ieon(struct hpet_dev *devp)
446 {
447         struct hpet_timer __iomem *timer;
448         struct hpet __iomem *hpet;
449         struct hpets *hpetp;
450         int irq;
451         unsigned long g, v, t, m;
452         unsigned long flags, isr;
453
454         timer = devp->hd_timer;
455         hpet = devp->hd_hpet;
456         hpetp = devp->hd_hpets;
457
458         if (!devp->hd_ireqfreq)
459                 return -EIO;
460
461         spin_lock_irq(&hpet_lock);
462
463         if (devp->hd_flags & HPET_IE) {
464                 spin_unlock_irq(&hpet_lock);
465                 return -EBUSY;
466         }
467
468         devp->hd_flags |= HPET_IE;
469
470         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
471                 devp->hd_flags |= HPET_SHARED_IRQ;
472         spin_unlock_irq(&hpet_lock);
473
474         irq = devp->hd_hdwirq;
475
476         if (irq) {
477                 unsigned long irq_flags;
478
479                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
480                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
481                                                 ? IRQF_SHARED : IRQF_DISABLED;
482                 if (request_irq(irq, hpet_interrupt, irq_flags,
483                                 devp->hd_name, (void *)devp)) {
484                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
485                         irq = 0;
486                 }
487         }
488
489         if (irq == 0) {
490                 spin_lock_irq(&hpet_lock);
491                 devp->hd_flags ^= HPET_IE;
492                 spin_unlock_irq(&hpet_lock);
493                 return -EIO;
494         }
495
496         devp->hd_irq = irq;
497         t = devp->hd_ireqfreq;
498         v = readq(&timer->hpet_config);
499
500         /* 64-bit comparators are not yet supported through the ioctls,
501          * so force this into 32-bit mode if it supports both modes
502          */
503         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
504
505         if (devp->hd_flags & HPET_PERIODIC) {
506                 g |= Tn_TYPE_CNF_MASK;
507                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
508                 writeq(v, &timer->hpet_config);
509                 local_irq_save(flags);
510
511                 /*
512                  * NOTE: First we modify the hidden accumulator
513                  * register supported by periodic-capable comparators.
514                  * We never want to modify the (single) counter; that
515                  * would affect all the comparators. The value written
516                  * is the counter value when the first interrupt is due.
517                  */
518                 m = read_counter(&hpet->hpet_mc);
519                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
520                 /*
521                  * Then we modify the comparator, indicating the period
522                  * for subsequent interrupt.
523                  */
524                 write_counter(t, &timer->hpet_compare);
525         } else {
526                 local_irq_save(flags);
527                 m = read_counter(&hpet->hpet_mc);
528                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
529         }
530
531         if (devp->hd_flags & HPET_SHARED_IRQ) {
532                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
533                 writel(isr, &hpet->hpet_isr);
534         }
535         writeq(g, &timer->hpet_config);
536         local_irq_restore(flags);
537
538         return 0;
539 }
540
541 /* converts Hz to number of timer ticks */
542 static inline unsigned long hpet_time_div(struct hpets *hpets,
543                                           unsigned long dis)
544 {
545         unsigned long long m;
546
547         m = hpets->hp_tick_freq + (dis >> 1);
548         do_div(m, dis);
549         return (unsigned long)m;
550 }
551
552 static int
553 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
554 {
555         struct hpet_timer __iomem *timer;
556         struct hpet __iomem *hpet;
557         struct hpets *hpetp;
558         int err;
559         unsigned long v;
560
561         switch (cmd) {
562         case HPET_IE_OFF:
563         case HPET_INFO:
564         case HPET_EPI:
565         case HPET_DPI:
566         case HPET_IRQFREQ:
567                 timer = devp->hd_timer;
568                 hpet = devp->hd_hpet;
569                 hpetp = devp->hd_hpets;
570                 break;
571         case HPET_IE_ON:
572                 return hpet_ioctl_ieon(devp);
573         default:
574                 return -EINVAL;
575         }
576
577         err = 0;
578
579         switch (cmd) {
580         case HPET_IE_OFF:
581                 if ((devp->hd_flags & HPET_IE) == 0)
582                         break;
583                 v = readq(&timer->hpet_config);
584                 v &= ~Tn_INT_ENB_CNF_MASK;
585                 writeq(v, &timer->hpet_config);
586                 if (devp->hd_irq) {
587                         free_irq(devp->hd_irq, devp);
588                         devp->hd_irq = 0;
589                 }
590                 devp->hd_flags ^= HPET_IE;
591                 break;
592         case HPET_INFO:
593                 {
594                         struct hpet_info info;
595
596                         if (devp->hd_ireqfreq)
597                                 info.hi_ireqfreq =
598                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
599                         else
600                                 info.hi_ireqfreq = 0;
601                         info.hi_flags =
602                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
603                         info.hi_hpet = hpetp->hp_which;
604                         info.hi_timer = devp - hpetp->hp_dev;
605                         if (kernel)
606                                 memcpy((void *)arg, &info, sizeof(info));
607                         else
608                                 if (copy_to_user((void __user *)arg, &info,
609                                                  sizeof(info)))
610                                         err = -EFAULT;
611                         break;
612                 }
613         case HPET_EPI:
614                 v = readq(&timer->hpet_config);
615                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
616                         err = -ENXIO;
617                         break;
618                 }
619                 devp->hd_flags |= HPET_PERIODIC;
620                 break;
621         case HPET_DPI:
622                 v = readq(&timer->hpet_config);
623                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
624                         err = -ENXIO;
625                         break;
626                 }
627                 if (devp->hd_flags & HPET_PERIODIC &&
628                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
629                         v = readq(&timer->hpet_config);
630                         v ^= Tn_TYPE_CNF_MASK;
631                         writeq(v, &timer->hpet_config);
632                 }
633                 devp->hd_flags &= ~HPET_PERIODIC;
634                 break;
635         case HPET_IRQFREQ:
636                 if (!kernel && (arg > hpet_max_freq) &&
637                     !capable(CAP_SYS_RESOURCE)) {
638                         err = -EACCES;
639                         break;
640                 }
641
642                 if (!arg) {
643                         err = -EINVAL;
644                         break;
645                 }
646
647                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
648         }
649
650         return err;
651 }
652
653 static const struct file_operations hpet_fops = {
654         .owner = THIS_MODULE,
655         .llseek = no_llseek,
656         .read = hpet_read,
657         .poll = hpet_poll,
658         .ioctl = hpet_ioctl,
659         .open = hpet_open,
660         .release = hpet_release,
661         .fasync = hpet_fasync,
662         .mmap = hpet_mmap,
663 };
664
665 static int hpet_is_known(struct hpet_data *hdp)
666 {
667         struct hpets *hpetp;
668
669         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
670                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
671                         return 1;
672
673         return 0;
674 }
675
676 static ctl_table hpet_table[] = {
677         {
678          .procname = "max-user-freq",
679          .data = &hpet_max_freq,
680          .maxlen = sizeof(int),
681          .mode = 0644,
682          .proc_handler = proc_dointvec,
683          },
684         {}
685 };
686
687 static ctl_table hpet_root[] = {
688         {
689          .procname = "hpet",
690          .maxlen = 0,
691          .mode = 0555,
692          .child = hpet_table,
693          },
694         {}
695 };
696
697 static ctl_table dev_root[] = {
698         {
699          .procname = "dev",
700          .maxlen = 0,
701          .mode = 0555,
702          .child = hpet_root,
703          },
704         {}
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(NULL, 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");