HPET: Remove spurious HPET busy warning message.
[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.htm
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(void)
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         if (file->f_flags & FASYNC)
431                 hpet_fasync(-1, file, 0);
432
433         file->private_data = NULL;
434         return 0;
435 }
436
437 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
438
439 static int
440 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
441            unsigned long arg)
442 {
443         struct hpet_dev *devp;
444
445         devp = file->private_data;
446         return hpet_ioctl_common(devp, cmd, arg, 0);
447 }
448
449 static int hpet_ioctl_ieon(struct hpet_dev *devp)
450 {
451         struct hpet_timer __iomem *timer;
452         struct hpet __iomem *hpet;
453         struct hpets *hpetp;
454         int irq;
455         unsigned long g, v, t, m;
456         unsigned long flags, isr;
457
458         timer = devp->hd_timer;
459         hpet = devp->hd_hpet;
460         hpetp = devp->hd_hpets;
461
462         if (!devp->hd_ireqfreq)
463                 return -EIO;
464
465         spin_lock_irq(&hpet_lock);
466
467         if (devp->hd_flags & HPET_IE) {
468                 spin_unlock_irq(&hpet_lock);
469                 return -EBUSY;
470         }
471
472         devp->hd_flags |= HPET_IE;
473
474         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
475                 devp->hd_flags |= HPET_SHARED_IRQ;
476         spin_unlock_irq(&hpet_lock);
477
478         irq = devp->hd_hdwirq;
479
480         if (irq) {
481                 unsigned long irq_flags;
482
483                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
484                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
485                                                 ? IRQF_SHARED : IRQF_DISABLED;
486                 if (request_irq(irq, hpet_interrupt, irq_flags,
487                                 devp->hd_name, (void *)devp)) {
488                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
489                         irq = 0;
490                 }
491         }
492
493         if (irq == 0) {
494                 spin_lock_irq(&hpet_lock);
495                 devp->hd_flags ^= HPET_IE;
496                 spin_unlock_irq(&hpet_lock);
497                 return -EIO;
498         }
499
500         devp->hd_irq = irq;
501         t = devp->hd_ireqfreq;
502         v = readq(&timer->hpet_config);
503
504         /* 64-bit comparators are not yet supported through the ioctls,
505          * so force this into 32-bit mode if it supports both modes
506          */
507         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
508
509         if (devp->hd_flags & HPET_PERIODIC) {
510                 write_counter(t, &timer->hpet_compare);
511                 g |= Tn_TYPE_CNF_MASK;
512                 v |= Tn_TYPE_CNF_MASK;
513                 writeq(v, &timer->hpet_config);
514                 v |= Tn_VAL_SET_CNF_MASK;
515                 writeq(v, &timer->hpet_config);
516                 local_irq_save(flags);
517
518                 /* NOTE:  what we modify here is a hidden accumulator
519                  * register supported by periodic-capable comparators.
520                  * We never want to modify the (single) counter; that
521                  * would affect all the comparators.
522                  */
523                 m = read_counter(&hpet->hpet_mc);
524                 write_counter(t + m + hpetp->hp_delta, &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          .ctl_name = CTL_UNNUMBERED,
679          .procname = "max-user-freq",
680          .data = &hpet_max_freq,
681          .maxlen = sizeof(int),
682          .mode = 0644,
683          .proc_handler = &proc_dointvec,
684          },
685         {.ctl_name = 0}
686 };
687
688 static ctl_table hpet_root[] = {
689         {
690          .ctl_name = CTL_UNNUMBERED,
691          .procname = "hpet",
692          .maxlen = 0,
693          .mode = 0555,
694          .child = hpet_table,
695          },
696         {.ctl_name = 0}
697 };
698
699 static ctl_table dev_root[] = {
700         {
701          .ctl_name = CTL_DEV,
702          .procname = "dev",
703          .maxlen = 0,
704          .mode = 0555,
705          .child = hpet_root,
706          },
707         {.ctl_name = 0}
708 };
709
710 static struct ctl_table_header *sysctl_header;
711
712 /*
713  * Adjustment for when arming the timer with
714  * initial conditions.  That is, main counter
715  * ticks expired before interrupts are enabled.
716  */
717 #define TICK_CALIBRATE  (1000UL)
718
719 static unsigned long hpet_calibrate(struct hpets *hpetp)
720 {
721         struct hpet_timer __iomem *timer = NULL;
722         unsigned long t, m, count, i, flags, start;
723         struct hpet_dev *devp;
724         int j;
725         struct hpet __iomem *hpet;
726
727         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
728                 if ((devp->hd_flags & HPET_OPEN) == 0) {
729                         timer = devp->hd_timer;
730                         break;
731                 }
732
733         if (!timer)
734                 return 0;
735
736         hpet = hpetp->hp_hpet;
737         t = read_counter(&timer->hpet_compare);
738
739         i = 0;
740         count = hpet_time_div(hpetp, TICK_CALIBRATE);
741
742         local_irq_save(flags);
743
744         start = read_counter(&hpet->hpet_mc);
745
746         do {
747                 m = read_counter(&hpet->hpet_mc);
748                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
749         } while (i++, (m - start) < count);
750
751         local_irq_restore(flags);
752
753         return (m - start) / i;
754 }
755
756 int hpet_alloc(struct hpet_data *hdp)
757 {
758         u64 cap, mcfg;
759         struct hpet_dev *devp;
760         u32 i, ntimer;
761         struct hpets *hpetp;
762         size_t siz;
763         struct hpet __iomem *hpet;
764         static struct hpets *last = NULL;
765         unsigned long period;
766         unsigned long long temp;
767         u32 remainder;
768
769         /*
770          * hpet_alloc can be called by platform dependent code.
771          * If platform dependent code has allocated the hpet that
772          * ACPI has also reported, then we catch it here.
773          */
774         if (hpet_is_known(hdp)) {
775                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
776                         __func__);
777                 return 0;
778         }
779
780         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
781                                       sizeof(struct hpet_dev));
782
783         hpetp = kzalloc(siz, GFP_KERNEL);
784
785         if (!hpetp)
786                 return -ENOMEM;
787
788         hpetp->hp_which = hpet_nhpet++;
789         hpetp->hp_hpet = hdp->hd_address;
790         hpetp->hp_hpet_phys = hdp->hd_phys_address;
791
792         hpetp->hp_ntimer = hdp->hd_nirqs;
793
794         for (i = 0; i < hdp->hd_nirqs; i++)
795                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
796
797         hpet = hpetp->hp_hpet;
798
799         cap = readq(&hpet->hpet_cap);
800
801         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
802
803         if (hpetp->hp_ntimer != ntimer) {
804                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
805                        " with number of timers\n");
806                 kfree(hpetp);
807                 return -ENODEV;
808         }
809
810         if (last)
811                 last->hp_next = hpetp;
812         else
813                 hpets = hpetp;
814
815         last = hpetp;
816
817         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
818                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
819         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
820         temp += period >> 1; /* round */
821         do_div(temp, period);
822         hpetp->hp_tick_freq = temp; /* ticks per second */
823
824         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
825                 hpetp->hp_which, hdp->hd_phys_address,
826                 hpetp->hp_ntimer > 1 ? "s" : "");
827         for (i = 0; i < hpetp->hp_ntimer; i++)
828                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
829         printk("\n");
830
831         temp = hpetp->hp_tick_freq;
832         remainder = do_div(temp, 1000000);
833         printk(KERN_INFO
834                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
835                 hpetp->hp_which, hpetp->hp_ntimer,
836                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
837                 (unsigned) temp, remainder);
838
839         mcfg = readq(&hpet->hpet_config);
840         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
841                 write_counter(0L, &hpet->hpet_mc);
842                 mcfg |= HPET_ENABLE_CNF_MASK;
843                 writeq(mcfg, &hpet->hpet_config);
844         }
845
846         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
847                 struct hpet_timer __iomem *timer;
848
849                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
850
851                 devp->hd_hpets = hpetp;
852                 devp->hd_hpet = hpet;
853                 devp->hd_timer = timer;
854
855                 /*
856                  * If the timer was reserved by platform code,
857                  * then make timer unavailable for opens.
858                  */
859                 if (hdp->hd_state & (1 << i)) {
860                         devp->hd_flags = HPET_OPEN;
861                         continue;
862                 }
863
864                 init_waitqueue_head(&devp->hd_waitqueue);
865         }
866
867         hpetp->hp_delta = hpet_calibrate(hpetp);
868
869 /* This clocksource driver currently only works on ia64 */
870 #ifdef CONFIG_IA64
871         if (!hpet_clocksource) {
872                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
873                 CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
874                 clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
875                                                 clocksource_hpet.shift);
876                 clocksource_register(&clocksource_hpet);
877                 hpetp->hp_clocksource = &clocksource_hpet;
878                 hpet_clocksource = &clocksource_hpet;
879         }
880 #endif
881
882         return 0;
883 }
884
885 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
886 {
887         struct hpet_data *hdp;
888         acpi_status status;
889         struct acpi_resource_address64 addr;
890
891         hdp = data;
892
893         status = acpi_resource_to_address64(res, &addr);
894
895         if (ACPI_SUCCESS(status)) {
896                 hdp->hd_phys_address = addr.minimum;
897                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
898
899                 if (hpet_is_known(hdp)) {
900                         iounmap(hdp->hd_address);
901                         return AE_ALREADY_EXISTS;
902                 }
903         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
904                 struct acpi_resource_fixed_memory32 *fixmem32;
905
906                 fixmem32 = &res->data.fixed_memory32;
907                 if (!fixmem32)
908                         return AE_NO_MEMORY;
909
910                 hdp->hd_phys_address = fixmem32->address;
911                 hdp->hd_address = ioremap(fixmem32->address,
912                                                 HPET_RANGE_SIZE);
913
914                 if (hpet_is_known(hdp)) {
915                         iounmap(hdp->hd_address);
916                         return AE_ALREADY_EXISTS;
917                 }
918         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
919                 struct acpi_resource_extended_irq *irqp;
920                 int i, irq;
921
922                 irqp = &res->data.extended_irq;
923
924                 for (i = 0; i < irqp->interrupt_count; i++) {
925                         irq = acpi_register_gsi(irqp->interrupts[i],
926                                       irqp->triggering, irqp->polarity);
927                         if (irq < 0)
928                                 return AE_ERROR;
929
930                         hdp->hd_irq[hdp->hd_nirqs] = irq;
931                         hdp->hd_nirqs++;
932                 }
933         }
934
935         return AE_OK;
936 }
937
938 static int hpet_acpi_add(struct acpi_device *device)
939 {
940         acpi_status result;
941         struct hpet_data data;
942
943         memset(&data, 0, sizeof(data));
944
945         result =
946             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
947                                 hpet_resources, &data);
948
949         if (ACPI_FAILURE(result))
950                 return -ENODEV;
951
952         if (!data.hd_address || !data.hd_nirqs) {
953                 printk("%s: no address or irqs in _CRS\n", __func__);
954                 return -ENODEV;
955         }
956
957         return hpet_alloc(&data);
958 }
959
960 static int hpet_acpi_remove(struct acpi_device *device, int type)
961 {
962         /* XXX need to unregister clocksource, dealloc mem, etc */
963         return -EINVAL;
964 }
965
966 static const struct acpi_device_id hpet_device_ids[] = {
967         {"PNP0103", 0},
968         {"", 0},
969 };
970 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
971
972 static struct acpi_driver hpet_acpi_driver = {
973         .name = "hpet",
974         .ids = hpet_device_ids,
975         .ops = {
976                 .add = hpet_acpi_add,
977                 .remove = hpet_acpi_remove,
978                 },
979 };
980
981 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
982
983 static int __init hpet_init(void)
984 {
985         int result;
986
987         result = misc_register(&hpet_misc);
988         if (result < 0)
989                 return -ENODEV;
990
991         sysctl_header = register_sysctl_table(dev_root);
992
993         result = acpi_bus_register_driver(&hpet_acpi_driver);
994         if (result < 0) {
995                 if (sysctl_header)
996                         unregister_sysctl_table(sysctl_header);
997                 misc_deregister(&hpet_misc);
998                 return result;
999         }
1000
1001         return 0;
1002 }
1003
1004 static void __exit hpet_exit(void)
1005 {
1006         acpi_bus_unregister_driver(&hpet_acpi_driver);
1007
1008         if (sysctl_header)
1009                 unregister_sysctl_table(sysctl_header);
1010         misc_deregister(&hpet_misc);
1011
1012         return;
1013 }
1014
1015 module_init(hpet_init);
1016 module_exit(hpet_exit);
1017 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1018 MODULE_LICENSE("GPL");