[PATCH] Fix mmap() of /dev/hpet
[linux-2.6.git] / drivers / char / hpet.c
1 /*
2  * Intel & MS High Precision Event Timer Implementation.
3  *
4  * Copyright (C) 2003 Intel Corporation
5  *      Venki Pallipadi
6  * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
7  *      Bob Picco <robert.picco@hp.com>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13
14 #include <linux/config.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/kernel.h>
18 #include <linux/types.h>
19 #include <linux/miscdevice.h>
20 #include <linux/major.h>
21 #include <linux/ioport.h>
22 #include <linux/fcntl.h>
23 #include <linux/init.h>
24 #include <linux/poll.h>
25 #include <linux/proc_fs.h>
26 #include <linux/spinlock.h>
27 #include <linux/sysctl.h>
28 #include <linux/wait.h>
29 #include <linux/bcd.h>
30 #include <linux/seq_file.h>
31 #include <linux/bitops.h>
32
33 #include <asm/current.h>
34 #include <asm/uaccess.h>
35 #include <asm/system.h>
36 #include <asm/io.h>
37 #include <asm/irq.h>
38 #include <asm/div64.h>
39
40 #include <linux/acpi.h>
41 #include <acpi/acpi_bus.h>
42 #include <linux/hpet.h>
43
44 /*
45  * The High Precision Event Timer driver.
46  * This driver is closely modelled after the rtc.c driver.
47  * http://www.intel.com/hardwaredesign/hpetspec.htm
48  */
49 #define HPET_USER_FREQ  (64)
50 #define HPET_DRIFT      (500)
51
52 static u32 hpet_ntimer, hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
53
54 /* A lock for concurrent access by app and isr hpet activity. */
55 static DEFINE_SPINLOCK(hpet_lock);
56 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
57 static DEFINE_SPINLOCK(hpet_task_lock);
58
59 #define HPET_DEV_NAME   (7)
60
61 struct hpet_dev {
62         struct hpets *hd_hpets;
63         struct hpet __iomem *hd_hpet;
64         struct hpet_timer __iomem *hd_timer;
65         unsigned long hd_ireqfreq;
66         unsigned long hd_irqdata;
67         wait_queue_head_t hd_waitqueue;
68         struct fasync_struct *hd_async_queue;
69         struct hpet_task *hd_task;
70         unsigned int hd_flags;
71         unsigned int hd_irq;
72         unsigned int hd_hdwirq;
73         char hd_name[HPET_DEV_NAME];
74 };
75
76 struct hpets {
77         struct hpets *hp_next;
78         struct hpet __iomem *hp_hpet;
79         unsigned long hp_hpet_phys;
80         struct time_interpolator *hp_interpolator;
81         unsigned long hp_period;
82         unsigned long hp_delta;
83         unsigned int hp_ntimer;
84         unsigned int hp_which;
85         struct hpet_dev hp_dev[1];
86 };
87
88 static struct hpets *hpets;
89
90 #define HPET_OPEN               0x0001
91 #define HPET_IE                 0x0002  /* interrupt enabled */
92 #define HPET_PERIODIC           0x0004
93
94 #if BITS_PER_LONG == 64
95 #define write_counter(V, MC)    writeq(V, MC)
96 #define read_counter(MC)        readq(MC)
97 #else
98 #define write_counter(V, MC)    writel(V, MC)
99 #define read_counter(MC)        readl(MC)
100 #endif
101
102 #ifndef readq
103 static inline unsigned long long readq(void __iomem *addr)
104 {
105         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
106 }
107 #endif
108
109 #ifndef writeq
110 static inline void writeq(unsigned long long v, void __iomem *addr)
111 {
112         writel(v & 0xffffffff, addr);
113         writel(v >> 32, addr + 4);
114 }
115 #endif
116
117 static irqreturn_t hpet_interrupt(int irq, void *data, struct pt_regs *regs)
118 {
119         struct hpet_dev *devp;
120         unsigned long isr;
121
122         devp = data;
123
124         spin_lock(&hpet_lock);
125         devp->hd_irqdata++;
126
127         /*
128          * For non-periodic timers, increment the accumulator.
129          * This has the effect of treating non-periodic like periodic.
130          */
131         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
132                 unsigned long m, t;
133
134                 t = devp->hd_ireqfreq;
135                 m = read_counter(&devp->hd_hpet->hpet_mc);
136                 write_counter(t + m + devp->hd_hpets->hp_delta,
137                               &devp->hd_timer->hpet_compare);
138         }
139
140         isr = (1 << (devp - devp->hd_hpets->hp_dev));
141         writeq(isr, &devp->hd_hpet->hpet_isr);
142         spin_unlock(&hpet_lock);
143
144         spin_lock(&hpet_task_lock);
145         if (devp->hd_task)
146                 devp->hd_task->ht_func(devp->hd_task->ht_data);
147         spin_unlock(&hpet_task_lock);
148
149         wake_up_interruptible(&devp->hd_waitqueue);
150
151         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
152
153         return IRQ_HANDLED;
154 }
155
156 static int hpet_open(struct inode *inode, struct file *file)
157 {
158         struct hpet_dev *devp;
159         struct hpets *hpetp;
160         int i;
161
162         if (file->f_mode & FMODE_WRITE)
163                 return -EINVAL;
164
165         spin_lock_irq(&hpet_lock);
166
167         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
168                 for (i = 0; i < hpetp->hp_ntimer; i++)
169                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
170                             || hpetp->hp_dev[i].hd_task)
171                                 continue;
172                         else {
173                                 devp = &hpetp->hp_dev[i];
174                                 break;
175                         }
176
177         if (!devp) {
178                 spin_unlock_irq(&hpet_lock);
179                 return -EBUSY;
180         }
181
182         file->private_data = devp;
183         devp->hd_irqdata = 0;
184         devp->hd_flags |= HPET_OPEN;
185         spin_unlock_irq(&hpet_lock);
186
187         return 0;
188 }
189
190 static ssize_t
191 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
192 {
193         DECLARE_WAITQUEUE(wait, current);
194         unsigned long data;
195         ssize_t retval;
196         struct hpet_dev *devp;
197
198         devp = file->private_data;
199         if (!devp->hd_ireqfreq)
200                 return -EIO;
201
202         if (count < sizeof(unsigned long))
203                 return -EINVAL;
204
205         add_wait_queue(&devp->hd_waitqueue, &wait);
206
207         for ( ; ; ) {
208                 set_current_state(TASK_INTERRUPTIBLE);
209
210                 spin_lock_irq(&hpet_lock);
211                 data = devp->hd_irqdata;
212                 devp->hd_irqdata = 0;
213                 spin_unlock_irq(&hpet_lock);
214
215                 if (data)
216                         break;
217                 else if (file->f_flags & O_NONBLOCK) {
218                         retval = -EAGAIN;
219                         goto out;
220                 } else if (signal_pending(current)) {
221                         retval = -ERESTARTSYS;
222                         goto out;
223                 }
224                 schedule();
225         }
226
227         retval = put_user(data, (unsigned long __user *)buf);
228         if (!retval)
229                 retval = sizeof(unsigned long);
230 out:
231         __set_current_state(TASK_RUNNING);
232         remove_wait_queue(&devp->hd_waitqueue, &wait);
233
234         return retval;
235 }
236
237 static unsigned int hpet_poll(struct file *file, poll_table * wait)
238 {
239         unsigned long v;
240         struct hpet_dev *devp;
241
242         devp = file->private_data;
243
244         if (!devp->hd_ireqfreq)
245                 return 0;
246
247         poll_wait(file, &devp->hd_waitqueue, wait);
248
249         spin_lock_irq(&hpet_lock);
250         v = devp->hd_irqdata;
251         spin_unlock_irq(&hpet_lock);
252
253         if (v != 0)
254                 return POLLIN | POLLRDNORM;
255
256         return 0;
257 }
258
259 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
260 {
261 #ifdef  CONFIG_HPET_MMAP
262         struct hpet_dev *devp;
263         unsigned long addr;
264
265         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
266                 return -EINVAL;
267
268         devp = file->private_data;
269         addr = devp->hd_hpets->hp_hpet_phys;
270
271         if (addr & (PAGE_SIZE - 1))
272                 return -ENOSYS;
273
274         vma->vm_flags |= VM_IO;
275         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
276
277         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
278                                         PAGE_SIZE, vma->vm_page_prot)) {
279                 printk(KERN_ERR "remap_pfn_range failed in hpet.c\n");
280                 return -EAGAIN;
281         }
282
283         return 0;
284 #else
285         return -ENOSYS;
286 #endif
287 }
288
289 static int hpet_fasync(int fd, struct file *file, int on)
290 {
291         struct hpet_dev *devp;
292
293         devp = file->private_data;
294
295         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
296                 return 0;
297         else
298                 return -EIO;
299 }
300
301 static int hpet_release(struct inode *inode, struct file *file)
302 {
303         struct hpet_dev *devp;
304         struct hpet_timer __iomem *timer;
305         int irq = 0;
306
307         devp = file->private_data;
308         timer = devp->hd_timer;
309
310         spin_lock_irq(&hpet_lock);
311
312         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
313                &timer->hpet_config);
314
315         irq = devp->hd_irq;
316         devp->hd_irq = 0;
317
318         devp->hd_ireqfreq = 0;
319
320         if (devp->hd_flags & HPET_PERIODIC
321             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
322                 unsigned long v;
323
324                 v = readq(&timer->hpet_config);
325                 v ^= Tn_TYPE_CNF_MASK;
326                 writeq(v, &timer->hpet_config);
327         }
328
329         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
330         spin_unlock_irq(&hpet_lock);
331
332         if (irq)
333                 free_irq(irq, devp);
334
335         if (file->f_flags & FASYNC)
336                 hpet_fasync(-1, file, 0);
337
338         file->private_data = NULL;
339         return 0;
340 }
341
342 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
343
344 static int
345 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
346            unsigned long arg)
347 {
348         struct hpet_dev *devp;
349
350         devp = file->private_data;
351         return hpet_ioctl_common(devp, cmd, arg, 0);
352 }
353
354 static int hpet_ioctl_ieon(struct hpet_dev *devp)
355 {
356         struct hpet_timer __iomem *timer;
357         struct hpet __iomem *hpet;
358         struct hpets *hpetp;
359         int irq;
360         unsigned long g, v, t, m;
361         unsigned long flags, isr;
362
363         timer = devp->hd_timer;
364         hpet = devp->hd_hpet;
365         hpetp = devp->hd_hpets;
366
367         v = readq(&timer->hpet_config);
368         spin_lock_irq(&hpet_lock);
369
370         if (devp->hd_flags & HPET_IE) {
371                 spin_unlock_irq(&hpet_lock);
372                 return -EBUSY;
373         }
374
375         devp->hd_flags |= HPET_IE;
376         spin_unlock_irq(&hpet_lock);
377
378         t = readq(&timer->hpet_config);
379         irq = devp->hd_hdwirq;
380
381         if (irq) {
382                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
383
384                 if (request_irq
385                     (irq, hpet_interrupt, SA_INTERRUPT, devp->hd_name, (void *)devp)) {
386                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
387                         irq = 0;
388                 }
389         }
390
391         if (irq == 0) {
392                 spin_lock_irq(&hpet_lock);
393                 devp->hd_flags ^= HPET_IE;
394                 spin_unlock_irq(&hpet_lock);
395                 return -EIO;
396         }
397
398         devp->hd_irq = irq;
399         t = devp->hd_ireqfreq;
400         v = readq(&timer->hpet_config);
401         g = v | Tn_INT_ENB_CNF_MASK;
402
403         if (devp->hd_flags & HPET_PERIODIC) {
404                 write_counter(t, &timer->hpet_compare);
405                 g |= Tn_TYPE_CNF_MASK;
406                 v |= Tn_TYPE_CNF_MASK;
407                 writeq(v, &timer->hpet_config);
408                 v |= Tn_VAL_SET_CNF_MASK;
409                 writeq(v, &timer->hpet_config);
410                 local_irq_save(flags);
411                 m = read_counter(&hpet->hpet_mc);
412                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
413         } else {
414                 local_irq_save(flags);
415                 m = read_counter(&hpet->hpet_mc);
416                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
417         }
418
419         isr = (1 << (devp - hpets->hp_dev));
420         writeq(isr, &hpet->hpet_isr);
421         writeq(g, &timer->hpet_config);
422         local_irq_restore(flags);
423
424         return 0;
425 }
426
427 static inline unsigned long hpet_time_div(unsigned long dis)
428 {
429         unsigned long long m = 1000000000000000ULL;
430
431         do_div(m, dis);
432
433         return (unsigned long)m;
434 }
435
436 static int
437 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
438 {
439         struct hpet_timer __iomem *timer;
440         struct hpet __iomem *hpet;
441         struct hpets *hpetp;
442         int err;
443         unsigned long v;
444
445         switch (cmd) {
446         case HPET_IE_OFF:
447         case HPET_INFO:
448         case HPET_EPI:
449         case HPET_DPI:
450         case HPET_IRQFREQ:
451                 timer = devp->hd_timer;
452                 hpet = devp->hd_hpet;
453                 hpetp = devp->hd_hpets;
454                 break;
455         case HPET_IE_ON:
456                 return hpet_ioctl_ieon(devp);
457         default:
458                 return -EINVAL;
459         }
460
461         err = 0;
462
463         switch (cmd) {
464         case HPET_IE_OFF:
465                 if ((devp->hd_flags & HPET_IE) == 0)
466                         break;
467                 v = readq(&timer->hpet_config);
468                 v &= ~Tn_INT_ENB_CNF_MASK;
469                 writeq(v, &timer->hpet_config);
470                 if (devp->hd_irq) {
471                         free_irq(devp->hd_irq, devp);
472                         devp->hd_irq = 0;
473                 }
474                 devp->hd_flags ^= HPET_IE;
475                 break;
476         case HPET_INFO:
477                 {
478                         struct hpet_info info;
479
480                         info.hi_ireqfreq = hpet_time_div(hpetp->hp_period *
481                                                          devp->hd_ireqfreq);
482                         info.hi_flags =
483                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
484                         info.hi_hpet = devp->hd_hpets->hp_which;
485                         info.hi_timer = devp - devp->hd_hpets->hp_dev;
486                         if (copy_to_user((void __user *)arg, &info, sizeof(info)))
487                                 err = -EFAULT;
488                         break;
489                 }
490         case HPET_EPI:
491                 v = readq(&timer->hpet_config);
492                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
493                         err = -ENXIO;
494                         break;
495                 }
496                 devp->hd_flags |= HPET_PERIODIC;
497                 break;
498         case HPET_DPI:
499                 v = readq(&timer->hpet_config);
500                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
501                         err = -ENXIO;
502                         break;
503                 }
504                 if (devp->hd_flags & HPET_PERIODIC &&
505                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
506                         v = readq(&timer->hpet_config);
507                         v ^= Tn_TYPE_CNF_MASK;
508                         writeq(v, &timer->hpet_config);
509                 }
510                 devp->hd_flags &= ~HPET_PERIODIC;
511                 break;
512         case HPET_IRQFREQ:
513                 if (!kernel && (arg > hpet_max_freq) &&
514                     !capable(CAP_SYS_RESOURCE)) {
515                         err = -EACCES;
516                         break;
517                 }
518
519                 if (arg & (arg - 1)) {
520                         err = -EINVAL;
521                         break;
522                 }
523
524                 devp->hd_ireqfreq = hpet_time_div(hpetp->hp_period * arg);
525         }
526
527         return err;
528 }
529
530 static struct file_operations hpet_fops = {
531         .owner = THIS_MODULE,
532         .llseek = no_llseek,
533         .read = hpet_read,
534         .poll = hpet_poll,
535         .ioctl = hpet_ioctl,
536         .open = hpet_open,
537         .release = hpet_release,
538         .fasync = hpet_fasync,
539         .mmap = hpet_mmap,
540 };
541
542 EXPORT_SYMBOL(hpet_alloc);
543 EXPORT_SYMBOL(hpet_register);
544 EXPORT_SYMBOL(hpet_unregister);
545 EXPORT_SYMBOL(hpet_control);
546
547 int hpet_register(struct hpet_task *tp, int periodic)
548 {
549         unsigned int i;
550         u64 mask;
551         struct hpet_timer __iomem *timer;
552         struct hpet_dev *devp;
553         struct hpets *hpetp;
554
555         switch (periodic) {
556         case 1:
557                 mask = Tn_PER_INT_CAP_MASK;
558                 break;
559         case 0:
560                 mask = 0;
561                 break;
562         default:
563                 return -EINVAL;
564         }
565
566         spin_lock_irq(&hpet_task_lock);
567         spin_lock(&hpet_lock);
568
569         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
570                 for (timer = hpetp->hp_hpet->hpet_timers, i = 0;
571                      i < hpetp->hp_ntimer; i++, timer++) {
572                         if ((readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK)
573                             != mask)
574                                 continue;
575
576                         devp = &hpetp->hp_dev[i];
577
578                         if (devp->hd_flags & HPET_OPEN || devp->hd_task) {
579                                 devp = NULL;
580                                 continue;
581                         }
582
583                         tp->ht_opaque = devp;
584                         devp->hd_task = tp;
585                         break;
586                 }
587
588         spin_unlock(&hpet_lock);
589         spin_unlock_irq(&hpet_task_lock);
590
591         if (tp->ht_opaque)
592                 return 0;
593         else
594                 return -EBUSY;
595 }
596
597 static inline int hpet_tpcheck(struct hpet_task *tp)
598 {
599         struct hpet_dev *devp;
600         struct hpets *hpetp;
601
602         devp = tp->ht_opaque;
603
604         if (!devp)
605                 return -ENXIO;
606
607         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
608                 if (devp >= hpetp->hp_dev
609                     && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
610                     && devp->hd_hpet == hpetp->hp_hpet)
611                         return 0;
612
613         return -ENXIO;
614 }
615
616 int hpet_unregister(struct hpet_task *tp)
617 {
618         struct hpet_dev *devp;
619         struct hpet_timer __iomem *timer;
620         int err;
621
622         if ((err = hpet_tpcheck(tp)))
623                 return err;
624
625         spin_lock_irq(&hpet_task_lock);
626         spin_lock(&hpet_lock);
627
628         devp = tp->ht_opaque;
629         if (devp->hd_task != tp) {
630                 spin_unlock(&hpet_lock);
631                 spin_unlock_irq(&hpet_task_lock);
632                 return -ENXIO;
633         }
634
635         timer = devp->hd_timer;
636         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
637                &timer->hpet_config);
638         devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
639         devp->hd_task = NULL;
640         spin_unlock(&hpet_lock);
641         spin_unlock_irq(&hpet_task_lock);
642
643         return 0;
644 }
645
646 int hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
647 {
648         struct hpet_dev *devp;
649         int err;
650
651         if ((err = hpet_tpcheck(tp)))
652                 return err;
653
654         spin_lock_irq(&hpet_lock);
655         devp = tp->ht_opaque;
656         if (devp->hd_task != tp) {
657                 spin_unlock_irq(&hpet_lock);
658                 return -ENXIO;
659         }
660         spin_unlock_irq(&hpet_lock);
661         return hpet_ioctl_common(devp, cmd, arg, 1);
662 }
663
664 static ctl_table hpet_table[] = {
665         {
666          .ctl_name = 1,
667          .procname = "max-user-freq",
668          .data = &hpet_max_freq,
669          .maxlen = sizeof(int),
670          .mode = 0644,
671          .proc_handler = &proc_dointvec,
672          },
673         {.ctl_name = 0}
674 };
675
676 static ctl_table hpet_root[] = {
677         {
678          .ctl_name = 1,
679          .procname = "hpet",
680          .maxlen = 0,
681          .mode = 0555,
682          .child = hpet_table,
683          },
684         {.ctl_name = 0}
685 };
686
687 static ctl_table dev_root[] = {
688         {
689          .ctl_name = CTL_DEV,
690          .procname = "dev",
691          .maxlen = 0,
692          .mode = 0555,
693          .child = hpet_root,
694          },
695         {.ctl_name = 0}
696 };
697
698 static struct ctl_table_header *sysctl_header;
699
700 static void hpet_register_interpolator(struct hpets *hpetp)
701 {
702 #ifdef  CONFIG_TIME_INTERPOLATION
703         struct time_interpolator *ti;
704
705         ti = kmalloc(sizeof(*ti), GFP_KERNEL);
706         if (!ti)
707                 return;
708
709         memset(ti, 0, sizeof(*ti));
710         ti->source = TIME_SOURCE_MMIO64;
711         ti->shift = 10;
712         ti->addr = &hpetp->hp_hpet->hpet_mc;
713         ti->frequency = hpet_time_div(hpets->hp_period);
714         ti->drift = HPET_DRIFT;
715         ti->mask = -1;
716
717         hpetp->hp_interpolator = ti;
718         register_time_interpolator(ti);
719 #endif
720 }
721
722 /*
723  * Adjustment for when arming the timer with
724  * initial conditions.  That is, main counter
725  * ticks expired before interrupts are enabled.
726  */
727 #define TICK_CALIBRATE  (1000UL)
728
729 static unsigned long hpet_calibrate(struct hpets *hpetp)
730 {
731         struct hpet_timer __iomem *timer = NULL;
732         unsigned long t, m, count, i, flags, start;
733         struct hpet_dev *devp;
734         int j;
735         struct hpet __iomem *hpet;
736
737         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
738                 if ((devp->hd_flags & HPET_OPEN) == 0) {
739                         timer = devp->hd_timer;
740                         break;
741                 }
742
743         if (!timer)
744                 return 0;
745
746         hpet = hpets->hp_hpet;
747         t = read_counter(&timer->hpet_compare);
748
749         i = 0;
750         count = hpet_time_div(hpetp->hp_period * TICK_CALIBRATE);
751
752         local_irq_save(flags);
753
754         start = read_counter(&hpet->hpet_mc);
755
756         do {
757                 m = read_counter(&hpet->hpet_mc);
758                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
759         } while (i++, (m - start) < count);
760
761         local_irq_restore(flags);
762
763         return (m - start) / i;
764 }
765
766 int hpet_alloc(struct hpet_data *hdp)
767 {
768         u64 cap, mcfg;
769         struct hpet_dev *devp;
770         u32 i, ntimer;
771         struct hpets *hpetp;
772         size_t siz;
773         struct hpet __iomem *hpet;
774         static struct hpets *last = (struct hpets *)0;
775         unsigned long ns;
776
777         /*
778          * hpet_alloc can be called by platform dependent code.
779          * if platform dependent code has allocated the hpet
780          * ACPI also reports hpet, then we catch it here.
781          */
782         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
783                 if (hpetp->hp_hpet == hdp->hd_address)
784                         return 0;
785
786         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
787                                       sizeof(struct hpet_dev));
788
789         hpetp = kmalloc(siz, GFP_KERNEL);
790
791         if (!hpetp)
792                 return -ENOMEM;
793
794         memset(hpetp, 0, siz);
795
796         hpetp->hp_which = hpet_nhpet++;
797         hpetp->hp_hpet = hdp->hd_address;
798         hpetp->hp_hpet_phys = hdp->hd_phys_address;
799
800         hpetp->hp_ntimer = hdp->hd_nirqs;
801
802         for (i = 0; i < hdp->hd_nirqs; i++)
803                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
804
805         hpet = hpetp->hp_hpet;
806
807         cap = readq(&hpet->hpet_cap);
808
809         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
810
811         if (hpetp->hp_ntimer != ntimer) {
812                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
813                        " with number of timers\n");
814                 kfree(hpetp);
815                 return -ENODEV;
816         }
817
818         if (last)
819                 last->hp_next = hpetp;
820         else
821                 hpets = hpetp;
822
823         last = hpetp;
824
825         hpetp->hp_period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
826             HPET_COUNTER_CLK_PERIOD_SHIFT;
827
828         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
829                 hpetp->hp_which, hdp->hd_phys_address,
830                 hpetp->hp_ntimer > 1 ? "s" : "");
831         for (i = 0; i < hpetp->hp_ntimer; i++)
832                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
833         printk("\n");
834
835         ns = hpetp->hp_period;  /* femptoseconds, 10^-15 */
836         ns /= 1000000;          /* convert to nanoseconds, 10^-9 */
837         printk(KERN_INFO "hpet%d: %ldns tick, %d %d-bit timers\n",
838                 hpetp->hp_which, ns, hpetp->hp_ntimer,
839                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32);
840
841         mcfg = readq(&hpet->hpet_config);
842         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
843                 write_counter(0L, &hpet->hpet_mc);
844                 mcfg |= HPET_ENABLE_CNF_MASK;
845                 writeq(mcfg, &hpet->hpet_config);
846         }
847
848         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer;
849              i++, hpet_ntimer++, devp++) {
850                 unsigned long v;
851                 struct hpet_timer __iomem *timer;
852
853                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
854                 v = readq(&timer->hpet_config);
855
856                 devp->hd_hpets = hpetp;
857                 devp->hd_hpet = hpet;
858                 devp->hd_timer = timer;
859
860                 /*
861                  * If the timer was reserved by platform code,
862                  * then make timer unavailable for opens.
863                  */
864                 if (hdp->hd_state & (1 << i)) {
865                         devp->hd_flags = HPET_OPEN;
866                         continue;
867                 }
868
869                 init_waitqueue_head(&devp->hd_waitqueue);
870         }
871
872         hpetp->hp_delta = hpet_calibrate(hpetp);
873         hpet_register_interpolator(hpetp);
874
875         return 0;
876 }
877
878 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
879 {
880         struct hpet_data *hdp;
881         acpi_status status;
882         struct acpi_resource_address64 addr;
883         struct hpets *hpetp;
884
885         hdp = data;
886
887         status = acpi_resource_to_address64(res, &addr);
888
889         if (ACPI_SUCCESS(status)) {
890                 unsigned long size;
891
892                 size = addr.max_address_range - addr.min_address_range + 1;
893                 hdp->hd_phys_address = addr.min_address_range;
894                 hdp->hd_address = ioremap(addr.min_address_range, size);
895
896                 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
897                         if (hpetp->hp_hpet == hdp->hd_address)
898                                 return -EBUSY;
899         } else if (res->id == ACPI_RSTYPE_EXT_IRQ) {
900                 struct acpi_resource_ext_irq *irqp;
901                 int i;
902
903                 irqp = &res->data.extended_irq;
904
905                 if (irqp->number_of_interrupts > 0) {
906                         hdp->hd_nirqs = irqp->number_of_interrupts;
907
908                         for (i = 0; i < hdp->hd_nirqs; i++) {
909                                 int rc =
910                                     acpi_register_gsi(irqp->interrupts[i],
911                                                       irqp->edge_level,
912                                                       irqp->active_high_low);
913                                 if (rc < 0)
914                                         return AE_ERROR;
915                                 hdp->hd_irq[i] = rc;
916                         }
917                 }
918         }
919
920         return AE_OK;
921 }
922
923 static int hpet_acpi_add(struct acpi_device *device)
924 {
925         acpi_status result;
926         struct hpet_data data;
927
928         memset(&data, 0, sizeof(data));
929
930         result =
931             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
932                                 hpet_resources, &data);
933
934         if (ACPI_FAILURE(result))
935                 return -ENODEV;
936
937         if (!data.hd_address || !data.hd_nirqs) {
938                 printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
939                 return -ENODEV;
940         }
941
942         return hpet_alloc(&data);
943 }
944
945 static int hpet_acpi_remove(struct acpi_device *device, int type)
946 {
947         /* XXX need to unregister interpolator, dealloc mem, etc */
948         return -EINVAL;
949 }
950
951 static struct acpi_driver hpet_acpi_driver = {
952         .name = "hpet",
953         .ids = "PNP0103",
954         .ops = {
955                 .add = hpet_acpi_add,
956                 .remove = hpet_acpi_remove,
957                 },
958 };
959
960 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
961
962 static int __init hpet_init(void)
963 {
964         int result;
965
966         result = misc_register(&hpet_misc);
967         if (result < 0)
968                 return -ENODEV;
969
970         sysctl_header = register_sysctl_table(dev_root, 0);
971
972         result = acpi_bus_register_driver(&hpet_acpi_driver);
973         if (result < 0) {
974                 if (sysctl_header)
975                         unregister_sysctl_table(sysctl_header);
976                 misc_deregister(&hpet_misc);
977                 return result;
978         }
979
980         return 0;
981 }
982
983 static void __exit hpet_exit(void)
984 {
985         acpi_bus_unregister_driver(&hpet_acpi_driver);
986
987         if (sysctl_header)
988                 unregister_sysctl_table(sysctl_header);
989         misc_deregister(&hpet_misc);
990
991         return;
992 }
993
994 module_init(hpet_init);
995 module_exit(hpet_exit);
996 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
997 MODULE_LICENSE("GPL");