1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Intel & MS High Precision Event Timer Implementation.
4 *
5 * Copyright (C) 2003 Intel Corporation
6 * Venki Pallipadi
7 * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
8 * Bob Picco <robert.picco@hp.com>
9 */
10
11#include <linux/interrupt.h>
12#include <linux/kernel.h>
13#include <linux/types.h>
14#include <linux/miscdevice.h>
15#include <linux/major.h>
16#include <linux/ioport.h>
17#include <linux/fcntl.h>
18#include <linux/init.h>
19#include <linux/io-64-nonatomic-lo-hi.h>
20#include <linux/poll.h>
21#include <linux/mm.h>
22#include <linux/proc_fs.h>
23#include <linux/spinlock.h>
24#include <linux/sysctl.h>
25#include <linux/wait.h>
26#include <linux/sched/signal.h>
27#include <linux/bcd.h>
28#include <linux/seq_file.h>
29#include <linux/bitops.h>
30#include <linux/compat.h>
31#include <linux/clocksource.h>
32#include <linux/uaccess.h>
33#include <linux/slab.h>
34#include <linux/io.h>
35#include <linux/acpi.h>
36#include <linux/hpet.h>
37#include <asm/current.h>
38#include <asm/irq.h>
39#include <asm/div64.h>
40
41/*
42 * The High Precision Event Timer driver.
43 * This driver is closely modelled after the rtc.c driver.
44 * See HPET spec revision 1.
45 */
46#define HPET_USER_FREQ (64)
47#define HPET_DRIFT (500)
48
49#define HPET_RANGE_SIZE 1024 /* from HPET spec */
50
51
52/* WARNING -- don't get confused. These macros are never used
53 * to write the (single) counter, and rarely to read it.
54 * They're badly named; to fix, someday.
55 */
56#if BITS_PER_LONG == 64
57#define write_counter(V, MC) writeq(V, MC)
58#define read_counter(MC) readq(MC)
59#else
60#define write_counter(V, MC) writel(V, MC)
61#define read_counter(MC) readl(MC)
62#endif
63
64static DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
65static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
66
67/* A lock for concurrent access by app and isr hpet activity. */
68static DEFINE_SPINLOCK(hpet_lock);
69
70#define HPET_DEV_NAME (7)
71
72struct hpet_dev {
73 struct hpets *hd_hpets;
74 struct hpet __iomem *hd_hpet;
75 struct hpet_timer __iomem *hd_timer;
76 unsigned long hd_ireqfreq;
77 unsigned long hd_irqdata;
78 wait_queue_head_t hd_waitqueue;
79 struct fasync_struct *hd_async_queue;
80 unsigned int hd_flags;
81 unsigned int hd_irq;
82 unsigned int hd_hdwirq;
83 char hd_name[HPET_DEV_NAME];
84};
85
86struct hpets {
87 struct hpets *hp_next;
88 struct hpet __iomem *hp_hpet;
89 unsigned long hp_hpet_phys;
90 unsigned long long hp_tick_freq;
91 unsigned long hp_delta;
92 unsigned int hp_ntimer;
93 unsigned int hp_which;
94 struct hpet_dev hp_dev[] __counted_by(hp_ntimer);
95};
96
97static struct hpets *hpets;
98
99#define HPET_OPEN 0x0001
100#define HPET_IE 0x0002 /* interrupt enabled */
101#define HPET_PERIODIC 0x0004
102#define HPET_SHARED_IRQ 0x0008
103
104static irqreturn_t hpet_interrupt(int irq, void *data)
105{
106 struct hpet_dev *devp;
107 unsigned long isr;
108
109 devp = data;
110 isr = 1 << (devp - devp->hd_hpets->hp_dev);
111
112 if ((devp->hd_flags & HPET_SHARED_IRQ) &&
113 !(isr & readl(addr: &devp->hd_hpet->hpet_isr)))
114 return IRQ_NONE;
115
116 spin_lock(lock: &hpet_lock);
117 devp->hd_irqdata++;
118
119 /*
120 * For non-periodic timers, increment the accumulator.
121 * This has the effect of treating non-periodic like periodic.
122 */
123 if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
124 unsigned long t, mc, base, k;
125 struct hpet __iomem *hpet = devp->hd_hpet;
126 struct hpets *hpetp = devp->hd_hpets;
127
128 t = devp->hd_ireqfreq;
129 read_counter(&devp->hd_timer->hpet_compare);
130 mc = read_counter(&hpet->hpet_mc);
131 /* The time for the next interrupt would logically be t + m,
132 * however, if we are very unlucky and the interrupt is delayed
133 * for longer than t then we will completely miss the next
134 * interrupt if we set t + m and an application will hang.
135 * Therefore we need to make a more complex computation assuming
136 * that there exists a k for which the following is true:
137 * k * t + base < mc + delta
138 * (k + 1) * t + base > mc + delta
139 * where t is the interval in hpet ticks for the given freq,
140 * base is the theoretical start value 0 < base < t,
141 * mc is the main counter value at the time of the interrupt,
142 * delta is the time it takes to write the a value to the
143 * comparator.
144 * k may then be computed as (mc - base + delta) / t .
145 */
146 base = mc % t;
147 k = (mc - base + hpetp->hp_delta) / t;
148 write_counter(t * (k + 1) + base,
149 &devp->hd_timer->hpet_compare);
150 }
151
152 if (devp->hd_flags & HPET_SHARED_IRQ)
153 writel(val: isr, addr: &devp->hd_hpet->hpet_isr);
154 spin_unlock(lock: &hpet_lock);
155
156 wake_up_interruptible(&devp->hd_waitqueue);
157
158 kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
159
160 return IRQ_HANDLED;
161}
162
163static void hpet_timer_set_irq(struct hpet_dev *devp)
164{
165 unsigned long v;
166 int irq, gsi;
167 struct hpet_timer __iomem *timer;
168
169 spin_lock_irq(lock: &hpet_lock);
170 if (devp->hd_hdwirq) {
171 spin_unlock_irq(lock: &hpet_lock);
172 return;
173 }
174
175 timer = devp->hd_timer;
176
177 /* we prefer level triggered mode */
178 v = readl(addr: &timer->hpet_config);
179 if (!(v & Tn_INT_TYPE_CNF_MASK)) {
180 v |= Tn_INT_TYPE_CNF_MASK;
181 writel(val: v, addr: &timer->hpet_config);
182 }
183 spin_unlock_irq(lock: &hpet_lock);
184
185 v = (readq(addr: &timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
186 Tn_INT_ROUTE_CAP_SHIFT;
187
188 /*
189 * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
190 * legacy device. In IO APIC mode, we skip all the legacy IRQS.
191 */
192 if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
193 v &= ~0xf3df;
194 else
195 v &= ~0xffff;
196
197 for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
198 if (irq >= nr_irqs) {
199 irq = HPET_MAX_IRQ;
200 break;
201 }
202
203 gsi = acpi_register_gsi(NULL, gsi: irq, ACPI_LEVEL_SENSITIVE,
204 ACPI_ACTIVE_LOW);
205 if (gsi > 0)
206 break;
207
208 /* FIXME: Setup interrupt source table */
209 }
210
211 if (irq < HPET_MAX_IRQ) {
212 spin_lock_irq(lock: &hpet_lock);
213 v = readl(addr: &timer->hpet_config);
214 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
215 writel(val: v, addr: &timer->hpet_config);
216 devp->hd_hdwirq = gsi;
217 spin_unlock_irq(lock: &hpet_lock);
218 }
219 return;
220}
221
222static int hpet_open(struct inode *inode, struct file *file)
223{
224 struct hpet_dev *devp;
225 struct hpets *hpetp;
226 int i;
227
228 if (file->f_mode & FMODE_WRITE)
229 return -EINVAL;
230
231 mutex_lock(&hpet_mutex);
232 spin_lock_irq(lock: &hpet_lock);
233
234 for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
235 for (i = 0; i < hpetp->hp_ntimer; i++)
236 if (hpetp->hp_dev[i].hd_flags & HPET_OPEN) {
237 continue;
238 } else {
239 devp = &hpetp->hp_dev[i];
240 break;
241 }
242
243 if (!devp) {
244 spin_unlock_irq(lock: &hpet_lock);
245 mutex_unlock(lock: &hpet_mutex);
246 return -EBUSY;
247 }
248
249 file->private_data = devp;
250 devp->hd_irqdata = 0;
251 devp->hd_flags |= HPET_OPEN;
252 spin_unlock_irq(lock: &hpet_lock);
253 mutex_unlock(lock: &hpet_mutex);
254
255 hpet_timer_set_irq(devp);
256
257 return 0;
258}
259
260static ssize_t
261hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
262{
263 DECLARE_WAITQUEUE(wait, current);
264 unsigned long data;
265 ssize_t retval;
266 struct hpet_dev *devp;
267
268 devp = file->private_data;
269 if (!devp->hd_ireqfreq)
270 return -EIO;
271
272 if (count < sizeof(unsigned long))
273 return -EINVAL;
274
275 add_wait_queue(wq_head: &devp->hd_waitqueue, wq_entry: &wait);
276
277 for ( ; ; ) {
278 set_current_state(TASK_INTERRUPTIBLE);
279
280 spin_lock_irq(lock: &hpet_lock);
281 data = devp->hd_irqdata;
282 devp->hd_irqdata = 0;
283 spin_unlock_irq(lock: &hpet_lock);
284
285 if (data) {
286 break;
287 } else if (file->f_flags & O_NONBLOCK) {
288 retval = -EAGAIN;
289 goto out;
290 } else if (signal_pending(current)) {
291 retval = -ERESTARTSYS;
292 goto out;
293 }
294 schedule();
295 }
296
297 retval = put_user(data, (unsigned long __user *)buf);
298 if (!retval)
299 retval = sizeof(unsigned long);
300out:
301 __set_current_state(TASK_RUNNING);
302 remove_wait_queue(wq_head: &devp->hd_waitqueue, wq_entry: &wait);
303
304 return retval;
305}
306
307static __poll_t hpet_poll(struct file *file, poll_table * wait)
308{
309 unsigned long v;
310 struct hpet_dev *devp;
311
312 devp = file->private_data;
313
314 if (!devp->hd_ireqfreq)
315 return 0;
316
317 poll_wait(filp: file, wait_address: &devp->hd_waitqueue, p: wait);
318
319 spin_lock_irq(lock: &hpet_lock);
320 v = devp->hd_irqdata;
321 spin_unlock_irq(lock: &hpet_lock);
322
323 if (v != 0)
324 return EPOLLIN | EPOLLRDNORM;
325
326 return 0;
327}
328
329#ifdef CONFIG_HPET_MMAP
330#ifdef CONFIG_HPET_MMAP_DEFAULT
331static int hpet_mmap_enabled = 1;
332#else
333static int hpet_mmap_enabled = 0;
334#endif
335
336static __init int hpet_mmap_enable(char *str)
337{
338 get_option(str: &str, pint: &hpet_mmap_enabled);
339 pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
340 return 1;
341}
342__setup("hpet_mmap=", hpet_mmap_enable);
343
344static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
345{
346 struct hpet_dev *devp;
347 unsigned long addr;
348
349 if (!hpet_mmap_enabled)
350 return -EACCES;
351
352 devp = file->private_data;
353 addr = devp->hd_hpets->hp_hpet_phys;
354
355 if (addr & (PAGE_SIZE - 1))
356 return -ENOSYS;
357
358 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
359 return vm_iomap_memory(vma, start: addr, PAGE_SIZE);
360}
361#else
362static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
363{
364 return -ENOSYS;
365}
366#endif
367
368static int hpet_fasync(int fd, struct file *file, int on)
369{
370 struct hpet_dev *devp;
371
372 devp = file->private_data;
373
374 if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
375 return 0;
376 else
377 return -EIO;
378}
379
380static int hpet_release(struct inode *inode, struct file *file)
381{
382 struct hpet_dev *devp;
383 struct hpet_timer __iomem *timer;
384 int irq = 0;
385
386 devp = file->private_data;
387 timer = devp->hd_timer;
388
389 spin_lock_irq(lock: &hpet_lock);
390
391 writeq(val: (readq(addr: &timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
392 addr: &timer->hpet_config);
393
394 irq = devp->hd_irq;
395 devp->hd_irq = 0;
396
397 devp->hd_ireqfreq = 0;
398
399 if (devp->hd_flags & HPET_PERIODIC
400 && readq(addr: &timer->hpet_config) & Tn_TYPE_CNF_MASK) {
401 unsigned long v;
402
403 v = readq(addr: &timer->hpet_config);
404 v ^= Tn_TYPE_CNF_MASK;
405 writeq(val: v, addr: &timer->hpet_config);
406 }
407
408 devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
409 spin_unlock_irq(lock: &hpet_lock);
410
411 if (irq)
412 free_irq(irq, devp);
413
414 file->private_data = NULL;
415 return 0;
416}
417
418static int hpet_ioctl_ieon(struct hpet_dev *devp)
419{
420 struct hpet_timer __iomem *timer;
421 struct hpet __iomem *hpet;
422 struct hpets *hpetp;
423 int irq;
424 unsigned long g, v, t, m;
425 unsigned long flags, isr;
426
427 timer = devp->hd_timer;
428 hpet = devp->hd_hpet;
429 hpetp = devp->hd_hpets;
430
431 if (!devp->hd_ireqfreq)
432 return -EIO;
433
434 spin_lock_irq(lock: &hpet_lock);
435
436 if (devp->hd_flags & HPET_IE) {
437 spin_unlock_irq(lock: &hpet_lock);
438 return -EBUSY;
439 }
440
441 devp->hd_flags |= HPET_IE;
442
443 if (readl(addr: &timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
444 devp->hd_flags |= HPET_SHARED_IRQ;
445 spin_unlock_irq(lock: &hpet_lock);
446
447 irq = devp->hd_hdwirq;
448
449 if (irq) {
450 unsigned long irq_flags;
451
452 if (devp->hd_flags & HPET_SHARED_IRQ) {
453 /*
454 * To prevent the interrupt handler from seeing an
455 * unwanted interrupt status bit, program the timer
456 * so that it will not fire in the near future ...
457 */
458 writel(readl(addr: &timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
459 addr: &timer->hpet_config);
460 write_counter(read_counter(&hpet->hpet_mc),
461 &timer->hpet_compare);
462 /* ... and clear any left-over status. */
463 isr = 1 << (devp - devp->hd_hpets->hp_dev);
464 writel(val: isr, addr: &hpet->hpet_isr);
465 }
466
467 sprintf(buf: devp->hd_name, fmt: "hpet%d", (int)(devp - hpetp->hp_dev));
468 irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
469 if (request_irq(irq, handler: hpet_interrupt, flags: irq_flags,
470 name: devp->hd_name, dev: (void *)devp)) {
471 printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
472 irq = 0;
473 }
474 }
475
476 if (irq == 0) {
477 spin_lock_irq(lock: &hpet_lock);
478 devp->hd_flags ^= HPET_IE;
479 spin_unlock_irq(lock: &hpet_lock);
480 return -EIO;
481 }
482
483 devp->hd_irq = irq;
484 t = devp->hd_ireqfreq;
485 v = readq(addr: &timer->hpet_config);
486
487 /* 64-bit comparators are not yet supported through the ioctls,
488 * so force this into 32-bit mode if it supports both modes
489 */
490 g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
491
492 if (devp->hd_flags & HPET_PERIODIC) {
493 g |= Tn_TYPE_CNF_MASK;
494 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
495 writeq(val: v, addr: &timer->hpet_config);
496 local_irq_save(flags);
497
498 /*
499 * NOTE: First we modify the hidden accumulator
500 * register supported by periodic-capable comparators.
501 * We never want to modify the (single) counter; that
502 * would affect all the comparators. The value written
503 * is the counter value when the first interrupt is due.
504 */
505 m = read_counter(&hpet->hpet_mc);
506 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
507 /*
508 * Then we modify the comparator, indicating the period
509 * for subsequent interrupt.
510 */
511 write_counter(t, &timer->hpet_compare);
512 } else {
513 local_irq_save(flags);
514 m = read_counter(&hpet->hpet_mc);
515 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
516 }
517
518 if (devp->hd_flags & HPET_SHARED_IRQ) {
519 isr = 1 << (devp - devp->hd_hpets->hp_dev);
520 writel(val: isr, addr: &hpet->hpet_isr);
521 }
522 writeq(val: g, addr: &timer->hpet_config);
523 local_irq_restore(flags);
524
525 return 0;
526}
527
528/* converts Hz to number of timer ticks */
529static inline unsigned long hpet_time_div(struct hpets *hpets,
530 unsigned long dis)
531{
532 unsigned long long m;
533
534 m = hpets->hp_tick_freq + (dis >> 1);
535 return div64_ul(m, dis);
536}
537
538static int
539hpet_ioctl_common(struct hpet_dev *devp, unsigned int cmd, unsigned long arg,
540 struct hpet_info *info)
541{
542 struct hpet_timer __iomem *timer;
543 struct hpets *hpetp;
544 int err;
545 unsigned long v;
546
547 switch (cmd) {
548 case HPET_IE_OFF:
549 case HPET_INFO:
550 case HPET_EPI:
551 case HPET_DPI:
552 case HPET_IRQFREQ:
553 timer = devp->hd_timer;
554 hpetp = devp->hd_hpets;
555 break;
556 case HPET_IE_ON:
557 return hpet_ioctl_ieon(devp);
558 default:
559 return -EINVAL;
560 }
561
562 err = 0;
563
564 switch (cmd) {
565 case HPET_IE_OFF:
566 if ((devp->hd_flags & HPET_IE) == 0)
567 break;
568 v = readq(addr: &timer->hpet_config);
569 v &= ~Tn_INT_ENB_CNF_MASK;
570 writeq(val: v, addr: &timer->hpet_config);
571 if (devp->hd_irq) {
572 free_irq(devp->hd_irq, devp);
573 devp->hd_irq = 0;
574 }
575 devp->hd_flags ^= HPET_IE;
576 break;
577 case HPET_INFO:
578 {
579 memset(info, 0, sizeof(*info));
580 if (devp->hd_ireqfreq)
581 info->hi_ireqfreq =
582 hpet_time_div(hpets: hpetp, dis: devp->hd_ireqfreq);
583 info->hi_flags =
584 readq(addr: &timer->hpet_config) & Tn_PER_INT_CAP_MASK;
585 info->hi_hpet = hpetp->hp_which;
586 info->hi_timer = devp - hpetp->hp_dev;
587 break;
588 }
589 case HPET_EPI:
590 v = readq(addr: &timer->hpet_config);
591 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
592 err = -ENXIO;
593 break;
594 }
595 devp->hd_flags |= HPET_PERIODIC;
596 break;
597 case HPET_DPI:
598 v = readq(addr: &timer->hpet_config);
599 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
600 err = -ENXIO;
601 break;
602 }
603 if (devp->hd_flags & HPET_PERIODIC &&
604 readq(addr: &timer->hpet_config) & Tn_TYPE_CNF_MASK) {
605 v = readq(addr: &timer->hpet_config);
606 v ^= Tn_TYPE_CNF_MASK;
607 writeq(val: v, addr: &timer->hpet_config);
608 }
609 devp->hd_flags &= ~HPET_PERIODIC;
610 break;
611 case HPET_IRQFREQ:
612 if ((arg > hpet_max_freq) &&
613 !capable(CAP_SYS_RESOURCE)) {
614 err = -EACCES;
615 break;
616 }
617
618 if (!arg) {
619 err = -EINVAL;
620 break;
621 }
622
623 devp->hd_ireqfreq = hpet_time_div(hpets: hpetp, dis: arg);
624 }
625
626 return err;
627}
628
629static long
630hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
631{
632 struct hpet_info info;
633 int err;
634
635 mutex_lock(&hpet_mutex);
636 err = hpet_ioctl_common(devp: file->private_data, cmd, arg, info: &info);
637 mutex_unlock(lock: &hpet_mutex);
638
639 if ((cmd == HPET_INFO) && !err &&
640 (copy_to_user(to: (void __user *)arg, from: &info, n: sizeof(info))))
641 err = -EFAULT;
642
643 return err;
644}
645
646#ifdef CONFIG_COMPAT
647struct compat_hpet_info {
648 compat_ulong_t hi_ireqfreq; /* Hz */
649 compat_ulong_t hi_flags; /* information */
650 unsigned short hi_hpet;
651 unsigned short hi_timer;
652};
653
654static long
655hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
656{
657 struct hpet_info info;
658 int err;
659
660 mutex_lock(&hpet_mutex);
661 err = hpet_ioctl_common(devp: file->private_data, cmd, arg, info: &info);
662 mutex_unlock(lock: &hpet_mutex);
663
664 if ((cmd == HPET_INFO) && !err) {
665 struct compat_hpet_info __user *u = compat_ptr(uptr: arg);
666 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
667 put_user(info.hi_flags, &u->hi_flags) ||
668 put_user(info.hi_hpet, &u->hi_hpet) ||
669 put_user(info.hi_timer, &u->hi_timer))
670 err = -EFAULT;
671 }
672
673 return err;
674}
675#endif
676
677static const struct file_operations hpet_fops = {
678 .owner = THIS_MODULE,
679 .llseek = no_llseek,
680 .read = hpet_read,
681 .poll = hpet_poll,
682 .unlocked_ioctl = hpet_ioctl,
683#ifdef CONFIG_COMPAT
684 .compat_ioctl = hpet_compat_ioctl,
685#endif
686 .open = hpet_open,
687 .release = hpet_release,
688 .fasync = hpet_fasync,
689 .mmap = hpet_mmap,
690};
691
692static int hpet_is_known(struct hpet_data *hdp)
693{
694 struct hpets *hpetp;
695
696 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
697 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
698 return 1;
699
700 return 0;
701}
702
703static struct ctl_table hpet_table[] = {
704 {
705 .procname = "max-user-freq",
706 .data = &hpet_max_freq,
707 .maxlen = sizeof(int),
708 .mode = 0644,
709 .proc_handler = proc_dointvec,
710 },
711};
712
713static struct ctl_table_header *sysctl_header;
714
715/*
716 * Adjustment for when arming the timer with
717 * initial conditions. That is, main counter
718 * ticks expired before interrupts are enabled.
719 */
720#define TICK_CALIBRATE (1000UL)
721
722static unsigned long __hpet_calibrate(struct hpets *hpetp)
723{
724 struct hpet_timer __iomem *timer = NULL;
725 unsigned long t, m, count, i, flags, start;
726 struct hpet_dev *devp;
727 int j;
728 struct hpet __iomem *hpet;
729
730 for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
731 if ((devp->hd_flags & HPET_OPEN) == 0) {
732 timer = devp->hd_timer;
733 break;
734 }
735
736 if (!timer)
737 return 0;
738
739 hpet = hpetp->hp_hpet;
740 t = read_counter(&timer->hpet_compare);
741
742 i = 0;
743 count = hpet_time_div(hpets: hpetp, TICK_CALIBRATE);
744
745 local_irq_save(flags);
746
747 start = read_counter(&hpet->hpet_mc);
748
749 do {
750 m = read_counter(&hpet->hpet_mc);
751 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
752 } while (i++, (m - start) < count);
753
754 local_irq_restore(flags);
755
756 return (m - start) / i;
757}
758
759static unsigned long hpet_calibrate(struct hpets *hpetp)
760{
761 unsigned long ret = ~0UL;
762 unsigned long tmp;
763
764 /*
765 * Try to calibrate until return value becomes stable small value.
766 * If SMI interruption occurs in calibration loop, the return value
767 * will be big. This avoids its impact.
768 */
769 for ( ; ; ) {
770 tmp = __hpet_calibrate(hpetp);
771 if (ret <= tmp)
772 break;
773 ret = tmp;
774 }
775
776 return ret;
777}
778
779int hpet_alloc(struct hpet_data *hdp)
780{
781 u64 cap, mcfg;
782 struct hpet_dev *devp;
783 u32 i, ntimer;
784 struct hpets *hpetp;
785 struct hpet __iomem *hpet;
786 static struct hpets *last;
787 unsigned long period;
788 unsigned long long temp;
789 u32 remainder;
790
791 /*
792 * hpet_alloc can be called by platform dependent code.
793 * If platform dependent code has allocated the hpet that
794 * ACPI has also reported, then we catch it here.
795 */
796 if (hpet_is_known(hdp)) {
797 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
798 __func__);
799 return 0;
800 }
801
802 hpetp = kzalloc(struct_size(hpetp, hp_dev, hdp->hd_nirqs),
803 GFP_KERNEL);
804
805 if (!hpetp)
806 return -ENOMEM;
807
808 hpetp->hp_which = hpet_nhpet++;
809 hpetp->hp_hpet = hdp->hd_address;
810 hpetp->hp_hpet_phys = hdp->hd_phys_address;
811
812 hpetp->hp_ntimer = hdp->hd_nirqs;
813
814 for (i = 0; i < hdp->hd_nirqs; i++)
815 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
816
817 hpet = hpetp->hp_hpet;
818
819 cap = readq(addr: &hpet->hpet_cap);
820
821 ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
822
823 if (hpetp->hp_ntimer != ntimer) {
824 printk(KERN_WARNING "hpet: number irqs doesn't agree"
825 " with number of timers\n");
826 kfree(objp: hpetp);
827 return -ENODEV;
828 }
829
830 if (last)
831 last->hp_next = hpetp;
832 else
833 hpets = hpetp;
834
835 last = hpetp;
836
837 period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
838 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
839 temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
840 temp += period >> 1; /* round */
841 do_div(temp, period);
842 hpetp->hp_tick_freq = temp; /* ticks per second */
843
844 printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
845 hpetp->hp_which, hdp->hd_phys_address,
846 hpetp->hp_ntimer > 1 ? "s" : "");
847 for (i = 0; i < hpetp->hp_ntimer; i++)
848 printk(KERN_CONT "%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
849 printk(KERN_CONT "\n");
850
851 temp = hpetp->hp_tick_freq;
852 remainder = do_div(temp, 1000000);
853 printk(KERN_INFO
854 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
855 hpetp->hp_which, hpetp->hp_ntimer,
856 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
857 (unsigned) temp, remainder);
858
859 mcfg = readq(addr: &hpet->hpet_config);
860 if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
861 write_counter(0L, &hpet->hpet_mc);
862 mcfg |= HPET_ENABLE_CNF_MASK;
863 writeq(val: mcfg, addr: &hpet->hpet_config);
864 }
865
866 for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
867 struct hpet_timer __iomem *timer;
868
869 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
870
871 devp->hd_hpets = hpetp;
872 devp->hd_hpet = hpet;
873 devp->hd_timer = timer;
874
875 /*
876 * If the timer was reserved by platform code,
877 * then make timer unavailable for opens.
878 */
879 if (hdp->hd_state & (1 << i)) {
880 devp->hd_flags = HPET_OPEN;
881 continue;
882 }
883
884 init_waitqueue_head(&devp->hd_waitqueue);
885 }
886
887 hpetp->hp_delta = hpet_calibrate(hpetp);
888
889 return 0;
890}
891
892static acpi_status hpet_resources(struct acpi_resource *res, void *data)
893{
894 struct hpet_data *hdp;
895 acpi_status status;
896 struct acpi_resource_address64 addr;
897
898 hdp = data;
899
900 status = acpi_resource_to_address64(resource: res, out: &addr);
901
902 if (ACPI_SUCCESS(status)) {
903 hdp->hd_phys_address = addr.address.minimum;
904 hdp->hd_address = ioremap(offset: addr.address.minimum, size: addr.address.address_length);
905 if (!hdp->hd_address)
906 return AE_ERROR;
907
908 if (hpet_is_known(hdp)) {
909 iounmap(addr: hdp->hd_address);
910 return AE_ALREADY_EXISTS;
911 }
912 } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
913 struct acpi_resource_fixed_memory32 *fixmem32;
914
915 fixmem32 = &res->data.fixed_memory32;
916
917 hdp->hd_phys_address = fixmem32->address;
918 hdp->hd_address = ioremap(offset: fixmem32->address,
919 HPET_RANGE_SIZE);
920 if (!hdp->hd_address)
921 return AE_ERROR;
922
923 if (hpet_is_known(hdp)) {
924 iounmap(addr: hdp->hd_address);
925 return AE_ALREADY_EXISTS;
926 }
927 } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
928 struct acpi_resource_extended_irq *irqp;
929 int i, irq;
930
931 irqp = &res->data.extended_irq;
932
933 for (i = 0; i < irqp->interrupt_count; i++) {
934 if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
935 break;
936
937 irq = acpi_register_gsi(NULL, gsi: irqp->interrupts[i],
938 triggering: irqp->triggering,
939 polarity: irqp->polarity);
940 if (irq < 0)
941 return AE_ERROR;
942
943 hdp->hd_irq[hdp->hd_nirqs] = irq;
944 hdp->hd_nirqs++;
945 }
946 }
947
948 return AE_OK;
949}
950
951static int hpet_acpi_add(struct acpi_device *device)
952{
953 acpi_status result;
954 struct hpet_data data;
955
956 memset(&data, 0, sizeof(data));
957
958 result =
959 acpi_walk_resources(device: device->handle, METHOD_NAME__CRS,
960 user_function: hpet_resources, context: &data);
961
962 if (ACPI_FAILURE(result))
963 return -ENODEV;
964
965 if (!data.hd_address || !data.hd_nirqs) {
966 if (data.hd_address)
967 iounmap(addr: data.hd_address);
968 printk("%s: no address or irqs in _CRS\n", __func__);
969 return -ENODEV;
970 }
971
972 return hpet_alloc(hdp: &data);
973}
974
975static const struct acpi_device_id hpet_device_ids[] = {
976 {"PNP0103", 0},
977 {"", 0},
978};
979
980static struct acpi_driver hpet_acpi_driver = {
981 .name = "hpet",
982 .ids = hpet_device_ids,
983 .ops = {
984 .add = hpet_acpi_add,
985 },
986};
987
988static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
989
990static int __init hpet_init(void)
991{
992 int result;
993
994 result = misc_register(misc: &hpet_misc);
995 if (result < 0)
996 return -ENODEV;
997
998 sysctl_header = register_sysctl("dev/hpet", hpet_table);
999
1000 result = acpi_bus_register_driver(driver: &hpet_acpi_driver);
1001 if (result < 0) {
1002 if (sysctl_header)
1003 unregister_sysctl_table(table: sysctl_header);
1004 misc_deregister(misc: &hpet_misc);
1005 return result;
1006 }
1007
1008 return 0;
1009}
1010device_initcall(hpet_init);
1011
1012/*
1013MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1014MODULE_LICENSE("GPL");
1015*/
1016

source code of linux/drivers/char/hpet.c