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[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/labs/platcomp/hpet/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 unsigned long long __inline 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 void __inline 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         addr = __pa(addr);
277
278         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
279                                         PAGE_SIZE, vma->vm_page_prot)) {
280                 printk(KERN_ERR "remap_pfn_range failed in hpet.c\n");
281                 return -EAGAIN;
282         }
283
284         return 0;
285 #else
286         return -ENOSYS;
287 #endif
288 }
289
290 static int hpet_fasync(int fd, struct file *file, int on)
291 {
292         struct hpet_dev *devp;
293
294         devp = file->private_data;
295
296         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
297                 return 0;
298         else
299                 return -EIO;
300 }
301
302 static int hpet_release(struct inode *inode, struct file *file)
303 {
304         struct hpet_dev *devp;
305         struct hpet_timer __iomem *timer;
306         int irq = 0;
307
308         devp = file->private_data;
309         timer = devp->hd_timer;
310
311         spin_lock_irq(&hpet_lock);
312
313         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
314                &timer->hpet_config);
315
316         irq = devp->hd_irq;
317         devp->hd_irq = 0;
318
319         devp->hd_ireqfreq = 0;
320
321         if (devp->hd_flags & HPET_PERIODIC
322             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
323                 unsigned long v;
324
325                 v = readq(&timer->hpet_config);
326                 v ^= Tn_TYPE_CNF_MASK;
327                 writeq(v, &timer->hpet_config);
328         }
329
330         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
331         spin_unlock_irq(&hpet_lock);
332
333         if (irq)
334                 free_irq(irq, devp);
335
336         if (file->f_flags & FASYNC)
337                 hpet_fasync(-1, file, 0);
338
339         file->private_data = NULL;
340         return 0;
341 }
342
343 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
344
345 static int
346 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
347            unsigned long arg)
348 {
349         struct hpet_dev *devp;
350
351         devp = file->private_data;
352         return hpet_ioctl_common(devp, cmd, arg, 0);
353 }
354
355 static int hpet_ioctl_ieon(struct hpet_dev *devp)
356 {
357         struct hpet_timer __iomem *timer;
358         struct hpet __iomem *hpet;
359         struct hpets *hpetp;
360         int irq;
361         unsigned long g, v, t, m;
362         unsigned long flags, isr;
363
364         timer = devp->hd_timer;
365         hpet = devp->hd_hpet;
366         hpetp = devp->hd_hpets;
367
368         v = readq(&timer->hpet_config);
369         spin_lock_irq(&hpet_lock);
370
371         if (devp->hd_flags & HPET_IE) {
372                 spin_unlock_irq(&hpet_lock);
373                 return -EBUSY;
374         }
375
376         devp->hd_flags |= HPET_IE;
377         spin_unlock_irq(&hpet_lock);
378
379         t = readq(&timer->hpet_config);
380         irq = devp->hd_hdwirq;
381
382         if (irq) {
383                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
384
385                 if (request_irq
386                     (irq, hpet_interrupt, SA_INTERRUPT, devp->hd_name, (void *)devp)) {
387                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
388                         irq = 0;
389                 }
390         }
391
392         if (irq == 0) {
393                 spin_lock_irq(&hpet_lock);
394                 devp->hd_flags ^= HPET_IE;
395                 spin_unlock_irq(&hpet_lock);
396                 return -EIO;
397         }
398
399         devp->hd_irq = irq;
400         t = devp->hd_ireqfreq;
401         v = readq(&timer->hpet_config);
402         g = v | Tn_INT_ENB_CNF_MASK;
403
404         if (devp->hd_flags & HPET_PERIODIC) {
405                 write_counter(t, &timer->hpet_compare);
406                 g |= Tn_TYPE_CNF_MASK;
407                 v |= Tn_TYPE_CNF_MASK;
408                 writeq(v, &timer->hpet_config);
409                 v |= Tn_VAL_SET_CNF_MASK;
410                 writeq(v, &timer->hpet_config);
411                 local_irq_save(flags);
412                 m = read_counter(&hpet->hpet_mc);
413                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
414         } else {
415                 local_irq_save(flags);
416                 m = read_counter(&hpet->hpet_mc);
417                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
418         }
419
420         isr = (1 << (devp - hpets->hp_dev));
421         writeq(isr, &hpet->hpet_isr);
422         writeq(g, &timer->hpet_config);
423         local_irq_restore(flags);
424
425         return 0;
426 }
427
428 static inline unsigned long hpet_time_div(unsigned long dis)
429 {
430         unsigned long long m = 1000000000000000ULL;
431
432         do_div(m, dis);
433
434         return (unsigned long)m;
435 }
436
437 static int
438 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
439 {
440         struct hpet_timer __iomem *timer;
441         struct hpet __iomem *hpet;
442         struct hpets *hpetp;
443         int err;
444         unsigned long v;
445
446         switch (cmd) {
447         case HPET_IE_OFF:
448         case HPET_INFO:
449         case HPET_EPI:
450         case HPET_DPI:
451         case HPET_IRQFREQ:
452                 timer = devp->hd_timer;
453                 hpet = devp->hd_hpet;
454                 hpetp = devp->hd_hpets;
455                 break;
456         case HPET_IE_ON:
457                 return hpet_ioctl_ieon(devp);
458         default:
459                 return -EINVAL;
460         }
461
462         err = 0;
463
464         switch (cmd) {
465         case HPET_IE_OFF:
466                 if ((devp->hd_flags & HPET_IE) == 0)
467                         break;
468                 v = readq(&timer->hpet_config);
469                 v &= ~Tn_INT_ENB_CNF_MASK;
470                 writeq(v, &timer->hpet_config);
471                 if (devp->hd_irq) {
472                         free_irq(devp->hd_irq, devp);
473                         devp->hd_irq = 0;
474                 }
475                 devp->hd_flags ^= HPET_IE;
476                 break;
477         case HPET_INFO:
478                 {
479                         struct hpet_info info;
480
481                         info.hi_ireqfreq = hpet_time_div(hpetp->hp_period *
482                                                          devp->hd_ireqfreq);
483                         info.hi_flags =
484                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
485                         info.hi_hpet = devp->hd_hpets->hp_which;
486                         info.hi_timer = devp - devp->hd_hpets->hp_dev;
487                         if (copy_to_user((void __user *)arg, &info, sizeof(info)))
488                                 err = -EFAULT;
489                         break;
490                 }
491         case HPET_EPI:
492                 v = readq(&timer->hpet_config);
493                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
494                         err = -ENXIO;
495                         break;
496                 }
497                 devp->hd_flags |= HPET_PERIODIC;
498                 break;
499         case HPET_DPI:
500                 v = readq(&timer->hpet_config);
501                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
502                         err = -ENXIO;
503                         break;
504                 }
505                 if (devp->hd_flags & HPET_PERIODIC &&
506                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
507                         v = readq(&timer->hpet_config);
508                         v ^= Tn_TYPE_CNF_MASK;
509                         writeq(v, &timer->hpet_config);
510                 }
511                 devp->hd_flags &= ~HPET_PERIODIC;
512                 break;
513         case HPET_IRQFREQ:
514                 if (!kernel && (arg > hpet_max_freq) &&
515                     !capable(CAP_SYS_RESOURCE)) {
516                         err = -EACCES;
517                         break;
518                 }
519
520                 if (arg & (arg - 1)) {
521                         err = -EINVAL;
522                         break;
523                 }
524
525                 devp->hd_ireqfreq = hpet_time_div(hpetp->hp_period * arg);
526         }
527
528         return err;
529 }
530
531 static struct file_operations hpet_fops = {
532         .owner = THIS_MODULE,
533         .llseek = no_llseek,
534         .read = hpet_read,
535         .poll = hpet_poll,
536         .ioctl = hpet_ioctl,
537         .open = hpet_open,
538         .release = hpet_release,
539         .fasync = hpet_fasync,
540         .mmap = hpet_mmap,
541 };
542
543 EXPORT_SYMBOL(hpet_alloc);
544 EXPORT_SYMBOL(hpet_register);
545 EXPORT_SYMBOL(hpet_unregister);
546 EXPORT_SYMBOL(hpet_control);
547
548 int hpet_register(struct hpet_task *tp, int periodic)
549 {
550         unsigned int i;
551         u64 mask;
552         struct hpet_timer __iomem *timer;
553         struct hpet_dev *devp;
554         struct hpets *hpetp;
555
556         switch (periodic) {
557         case 1:
558                 mask = Tn_PER_INT_CAP_MASK;
559                 break;
560         case 0:
561                 mask = 0;
562                 break;
563         default:
564                 return -EINVAL;
565         }
566
567         spin_lock_irq(&hpet_task_lock);
568         spin_lock(&hpet_lock);
569
570         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
571                 for (timer = hpetp->hp_hpet->hpet_timers, i = 0;
572                      i < hpetp->hp_ntimer; i++, timer++) {
573                         if ((readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK)
574                             != mask)
575                                 continue;
576
577                         devp = &hpetp->hp_dev[i];
578
579                         if (devp->hd_flags & HPET_OPEN || devp->hd_task) {
580                                 devp = NULL;
581                                 continue;
582                         }
583
584                         tp->ht_opaque = devp;
585                         devp->hd_task = tp;
586                         break;
587                 }
588
589         spin_unlock(&hpet_lock);
590         spin_unlock_irq(&hpet_task_lock);
591
592         if (tp->ht_opaque)
593                 return 0;
594         else
595                 return -EBUSY;
596 }
597
598 static inline int hpet_tpcheck(struct hpet_task *tp)
599 {
600         struct hpet_dev *devp;
601         struct hpets *hpetp;
602
603         devp = tp->ht_opaque;
604
605         if (!devp)
606                 return -ENXIO;
607
608         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
609                 if (devp >= hpetp->hp_dev
610                     && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
611                     && devp->hd_hpet == hpetp->hp_hpet)
612                         return 0;
613
614         return -ENXIO;
615 }
616
617 int hpet_unregister(struct hpet_task *tp)
618 {
619         struct hpet_dev *devp;
620         struct hpet_timer __iomem *timer;
621         int err;
622
623         if ((err = hpet_tpcheck(tp)))
624                 return err;
625
626         spin_lock_irq(&hpet_task_lock);
627         spin_lock(&hpet_lock);
628
629         devp = tp->ht_opaque;
630         if (devp->hd_task != tp) {
631                 spin_unlock(&hpet_lock);
632                 spin_unlock_irq(&hpet_task_lock);
633                 return -ENXIO;
634         }
635
636         timer = devp->hd_timer;
637         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
638                &timer->hpet_config);
639         devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
640         devp->hd_task = NULL;
641         spin_unlock(&hpet_lock);
642         spin_unlock_irq(&hpet_task_lock);
643
644         return 0;
645 }
646
647 int hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
648 {
649         struct hpet_dev *devp;
650         int err;
651
652         if ((err = hpet_tpcheck(tp)))
653                 return err;
654
655         spin_lock_irq(&hpet_lock);
656         devp = tp->ht_opaque;
657         if (devp->hd_task != tp) {
658                 spin_unlock_irq(&hpet_lock);
659                 return -ENXIO;
660         }
661         spin_unlock_irq(&hpet_lock);
662         return hpet_ioctl_common(devp, cmd, arg, 1);
663 }
664
665 static ctl_table hpet_table[] = {
666         {
667          .ctl_name = 1,
668          .procname = "max-user-freq",
669          .data = &hpet_max_freq,
670          .maxlen = sizeof(int),
671          .mode = 0644,
672          .proc_handler = &proc_dointvec,
673          },
674         {.ctl_name = 0}
675 };
676
677 static ctl_table hpet_root[] = {
678         {
679          .ctl_name = 1,
680          .procname = "hpet",
681          .maxlen = 0,
682          .mode = 0555,
683          .child = hpet_table,
684          },
685         {.ctl_name = 0}
686 };
687
688 static ctl_table dev_root[] = {
689         {
690          .ctl_name = CTL_DEV,
691          .procname = "dev",
692          .maxlen = 0,
693          .mode = 0555,
694          .child = hpet_root,
695          },
696         {.ctl_name = 0}
697 };
698
699 static struct ctl_table_header *sysctl_header;
700
701 static void hpet_register_interpolator(struct hpets *hpetp)
702 {
703 #ifdef  CONFIG_TIME_INTERPOLATION
704         struct time_interpolator *ti;
705
706         ti = kmalloc(sizeof(*ti), GFP_KERNEL);
707         if (!ti)
708                 return;
709
710         memset(ti, 0, sizeof(*ti));
711         ti->source = TIME_SOURCE_MMIO64;
712         ti->shift = 10;
713         ti->addr = &hpetp->hp_hpet->hpet_mc;
714         ti->frequency = hpet_time_div(hpets->hp_period);
715         ti->drift = ti->frequency * HPET_DRIFT / 1000000;
716         ti->mask = -1;
717
718         hpetp->hp_interpolator = ti;
719         register_time_interpolator(ti);
720 #endif
721 }
722
723 /*
724  * Adjustment for when arming the timer with
725  * initial conditions.  That is, main counter
726  * ticks expired before interrupts are enabled.
727  */
728 #define TICK_CALIBRATE  (1000UL)
729
730 static unsigned long hpet_calibrate(struct hpets *hpetp)
731 {
732         struct hpet_timer __iomem *timer = NULL;
733         unsigned long t, m, count, i, flags, start;
734         struct hpet_dev *devp;
735         int j;
736         struct hpet __iomem *hpet;
737
738         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
739                 if ((devp->hd_flags & HPET_OPEN) == 0) {
740                         timer = devp->hd_timer;
741                         break;
742                 }
743
744         if (!timer)
745                 return 0;
746
747         hpet = hpets->hp_hpet;
748         t = read_counter(&timer->hpet_compare);
749
750         i = 0;
751         count = hpet_time_div(hpetp->hp_period * TICK_CALIBRATE);
752
753         local_irq_save(flags);
754
755         start = read_counter(&hpet->hpet_mc);
756
757         do {
758                 m = read_counter(&hpet->hpet_mc);
759                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
760         } while (i++, (m - start) < count);
761
762         local_irq_restore(flags);
763
764         return (m - start) / i;
765 }
766
767 int hpet_alloc(struct hpet_data *hdp)
768 {
769         u64 cap, mcfg;
770         struct hpet_dev *devp;
771         u32 i, ntimer;
772         struct hpets *hpetp;
773         size_t siz;
774         struct hpet __iomem *hpet;
775         static struct hpets *last = (struct hpets *)0;
776         unsigned long ns;
777
778         /*
779          * hpet_alloc can be called by platform dependent code.
780          * if platform dependent code has allocated the hpet
781          * ACPI also reports hpet, then we catch it here.
782          */
783         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
784                 if (hpetp->hp_hpet == hdp->hd_address)
785                         return 0;
786
787         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
788                                       sizeof(struct hpet_dev));
789
790         hpetp = kmalloc(siz, GFP_KERNEL);
791
792         if (!hpetp)
793                 return -ENOMEM;
794
795         memset(hpetp, 0, siz);
796
797         hpetp->hp_which = hpet_nhpet++;
798         hpetp->hp_hpet = hdp->hd_address;
799         hpetp->hp_hpet_phys = hdp->hd_phys_address;
800
801         hpetp->hp_ntimer = hdp->hd_nirqs;
802
803         for (i = 0; i < hdp->hd_nirqs; i++)
804                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
805
806         hpet = hpetp->hp_hpet;
807
808         cap = readq(&hpet->hpet_cap);
809
810         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
811
812         if (hpetp->hp_ntimer != ntimer) {
813                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
814                        " with number of timers\n");
815                 kfree(hpetp);
816                 return -ENODEV;
817         }
818
819         if (last)
820                 last->hp_next = hpetp;
821         else
822                 hpets = hpetp;
823
824         last = hpetp;
825
826         hpetp->hp_period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
827             HPET_COUNTER_CLK_PERIOD_SHIFT;
828
829         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
830                 hpetp->hp_which, hdp->hd_phys_address,
831                 hpetp->hp_ntimer > 1 ? "s" : "");
832         for (i = 0; i < hpetp->hp_ntimer; i++)
833                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
834         printk("\n");
835
836         ns = hpetp->hp_period;  /* femptoseconds, 10^-15 */
837         ns /= 1000000;          /* convert to nanoseconds, 10^-9 */
838         printk(KERN_INFO "hpet%d: %ldns tick, %d %d-bit timers\n",
839                 hpetp->hp_which, ns, hpetp->hp_ntimer,
840                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32);
841
842         mcfg = readq(&hpet->hpet_config);
843         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
844                 write_counter(0L, &hpet->hpet_mc);
845                 mcfg |= HPET_ENABLE_CNF_MASK;
846                 writeq(mcfg, &hpet->hpet_config);
847         }
848
849         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer;
850              i++, hpet_ntimer++, devp++) {
851                 unsigned long v;
852                 struct hpet_timer __iomem *timer;
853
854                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
855                 v = readq(&timer->hpet_config);
856
857                 devp->hd_hpets = hpetp;
858                 devp->hd_hpet = hpet;
859                 devp->hd_timer = timer;
860
861                 /*
862                  * If the timer was reserved by platform code,
863                  * then make timer unavailable for opens.
864                  */
865                 if (hdp->hd_state & (1 << i)) {
866                         devp->hd_flags = HPET_OPEN;
867                         continue;
868                 }
869
870                 init_waitqueue_head(&devp->hd_waitqueue);
871         }
872
873         hpetp->hp_delta = hpet_calibrate(hpetp);
874         hpet_register_interpolator(hpetp);
875
876         return 0;
877 }
878
879 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
880 {
881         struct hpet_data *hdp;
882         acpi_status status;
883         struct acpi_resource_address64 addr;
884         struct hpets *hpetp;
885
886         hdp = data;
887
888         status = acpi_resource_to_address64(res, &addr);
889
890         if (ACPI_SUCCESS(status)) {
891                 unsigned long size;
892
893                 size = addr.max_address_range - addr.min_address_range + 1;
894                 hdp->hd_phys_address = addr.min_address_range;
895                 hdp->hd_address = ioremap(addr.min_address_range, size);
896
897                 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
898                         if (hpetp->hp_hpet == hdp->hd_address)
899                                 return -EBUSY;
900         } else if (res->id == ACPI_RSTYPE_EXT_IRQ) {
901                 struct acpi_resource_ext_irq *irqp;
902                 int i;
903
904                 irqp = &res->data.extended_irq;
905
906                 if (irqp->number_of_interrupts > 0) {
907                         hdp->hd_nirqs = irqp->number_of_interrupts;
908
909                         for (i = 0; i < hdp->hd_nirqs; i++) {
910                                 int rc =
911                                     acpi_register_gsi(irqp->interrupts[i],
912                                                       irqp->edge_level,
913                                                       irqp->active_high_low);
914                                 if (rc < 0)
915                                         return AE_ERROR;
916                                 hdp->hd_irq[i] = rc;
917                         }
918                 }
919         }
920
921         return AE_OK;
922 }
923
924 static int hpet_acpi_add(struct acpi_device *device)
925 {
926         acpi_status result;
927         struct hpet_data data;
928
929         memset(&data, 0, sizeof(data));
930
931         result =
932             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
933                                 hpet_resources, &data);
934
935         if (ACPI_FAILURE(result))
936                 return -ENODEV;
937
938         if (!data.hd_address || !data.hd_nirqs) {
939                 printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
940                 return -ENODEV;
941         }
942
943         return hpet_alloc(&data);
944 }
945
946 static int hpet_acpi_remove(struct acpi_device *device, int type)
947 {
948         /* XXX need to unregister interpolator, dealloc mem, etc */
949         return -EINVAL;
950 }
951
952 static struct acpi_driver hpet_acpi_driver = {
953         .name = "hpet",
954         .ids = "PNP0103",
955         .ops = {
956                 .add = hpet_acpi_add,
957                 .remove = hpet_acpi_remove,
958                 },
959 };
960
961 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
962
963 static int __init hpet_init(void)
964 {
965         int result;
966
967         result = misc_register(&hpet_misc);
968         if (result < 0)
969                 return -ENODEV;
970
971         sysctl_header = register_sysctl_table(dev_root, 0);
972
973         result = acpi_bus_register_driver(&hpet_acpi_driver);
974         if (result < 0) {
975                 if (sysctl_header)
976                         unregister_sysctl_table(sysctl_header);
977                 misc_deregister(&hpet_misc);
978                 return result;
979         }
980
981         return 0;
982 }
983
984 static void __exit hpet_exit(void)
985 {
986         acpi_bus_unregister_driver(&hpet_acpi_driver);
987
988         if (sysctl_header)
989                 unregister_sysctl_table(sysctl_header);
990         misc_deregister(&hpet_misc);
991
992         return;
993 }
994
995 module_init(hpet_init);
996 module_exit(hpet_exit);
997 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
998 MODULE_LICENSE("GPL");