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 const unsigned int nr_irqs = irq_get_nr_irqs();
166 unsigned long v;
167 int irq, gsi;
168 struct hpet_timer __iomem *timer;
169
170 spin_lock_irq(lock: &hpet_lock);
171 if (devp->hd_hdwirq) {
172 spin_unlock_irq(lock: &hpet_lock);
173 return;
174 }
175
176 timer = devp->hd_timer;
177
178 /* we prefer level triggered mode */
179 v = readl(addr: &timer->hpet_config);
180 if (!(v & Tn_INT_TYPE_CNF_MASK)) {
181 v |= Tn_INT_TYPE_CNF_MASK;
182 writel(val: v, addr: &timer->hpet_config);
183 }
184 spin_unlock_irq(lock: &hpet_lock);
185
186 v = (readq(addr: &timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
187 Tn_INT_ROUTE_CAP_SHIFT;
188
189 /*
190 * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
191 * legacy device. In IO APIC mode, we skip all the legacy IRQS.
192 */
193 if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
194 v &= ~0xf3df;
195 else
196 v &= ~0xffff;
197
198 for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
199 if (irq >= nr_irqs) {
200 irq = HPET_MAX_IRQ;
201 break;
202 }
203
204 gsi = acpi_register_gsi(NULL, gsi: irq, ACPI_LEVEL_SENSITIVE,
205 ACPI_ACTIVE_LOW);
206 if (gsi > 0)
207 break;
208
209 /* FIXME: Setup interrupt source table */
210 }
211
212 if (irq < HPET_MAX_IRQ) {
213 spin_lock_irq(lock: &hpet_lock);
214 v = readl(addr: &timer->hpet_config);
215 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
216 writel(val: v, addr: &timer->hpet_config);
217 devp->hd_hdwirq = gsi;
218 spin_unlock_irq(lock: &hpet_lock);
219 }
220 return;
221}
222
223static int hpet_open(struct inode *inode, struct file *file)
224{
225 struct hpet_dev *devp;
226 struct hpets *hpetp;
227 int i;
228
229 if (file->f_mode & FMODE_WRITE)
230 return -EINVAL;
231
232 mutex_lock(&hpet_mutex);
233 spin_lock_irq(lock: &hpet_lock);
234
235 for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
236 for (i = 0; i < hpetp->hp_ntimer; i++)
237 if (hpetp->hp_dev[i].hd_flags & HPET_OPEN) {
238 continue;
239 } else {
240 devp = &hpetp->hp_dev[i];
241 break;
242 }
243
244 if (!devp) {
245 spin_unlock_irq(lock: &hpet_lock);
246 mutex_unlock(lock: &hpet_mutex);
247 return -EBUSY;
248 }
249
250 file->private_data = devp;
251 devp->hd_irqdata = 0;
252 devp->hd_flags |= HPET_OPEN;
253 spin_unlock_irq(lock: &hpet_lock);
254 mutex_unlock(lock: &hpet_mutex);
255
256 hpet_timer_set_irq(devp);
257
258 return 0;
259}
260
261static ssize_t
262hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
263{
264 DECLARE_WAITQUEUE(wait, current);
265 unsigned long data;
266 ssize_t retval;
267 struct hpet_dev *devp;
268
269 devp = file->private_data;
270 if (!devp->hd_ireqfreq)
271 return -EIO;
272
273 if (in_compat_syscall()) {
274 if (count < sizeof(compat_ulong_t))
275 return -EINVAL;
276 } else {
277 if (count < sizeof(unsigned long))
278 return -EINVAL;
279 }
280
281 add_wait_queue(wq_head: &devp->hd_waitqueue, wq_entry: &wait);
282
283 for ( ; ; ) {
284 set_current_state(TASK_INTERRUPTIBLE);
285
286 spin_lock_irq(lock: &hpet_lock);
287 data = devp->hd_irqdata;
288 devp->hd_irqdata = 0;
289 spin_unlock_irq(lock: &hpet_lock);
290
291 if (data) {
292 break;
293 } else if (file->f_flags & O_NONBLOCK) {
294 retval = -EAGAIN;
295 goto out;
296 } else if (signal_pending(current)) {
297 retval = -ERESTARTSYS;
298 goto out;
299 }
300 schedule();
301 }
302
303 if (in_compat_syscall()) {
304 retval = put_user(data, (compat_ulong_t __user *)buf);
305 if (!retval)
306 retval = sizeof(compat_ulong_t);
307 } else {
308 retval = put_user(data, (unsigned long __user *)buf);
309 if (!retval)
310 retval = sizeof(unsigned long);
311 }
312
313out:
314 __set_current_state(TASK_RUNNING);
315 remove_wait_queue(wq_head: &devp->hd_waitqueue, wq_entry: &wait);
316
317 return retval;
318}
319
320static __poll_t hpet_poll(struct file *file, poll_table * wait)
321{
322 unsigned long v;
323 struct hpet_dev *devp;
324
325 devp = file->private_data;
326
327 if (!devp->hd_ireqfreq)
328 return 0;
329
330 poll_wait(filp: file, wait_address: &devp->hd_waitqueue, p: wait);
331
332 spin_lock_irq(lock: &hpet_lock);
333 v = devp->hd_irqdata;
334 spin_unlock_irq(lock: &hpet_lock);
335
336 if (v != 0)
337 return EPOLLIN | EPOLLRDNORM;
338
339 return 0;
340}
341
342#ifdef CONFIG_HPET_MMAP
343#ifdef CONFIG_HPET_MMAP_DEFAULT
344static int hpet_mmap_enabled = 1;
345#else
346static int hpet_mmap_enabled = 0;
347#endif
348
349static __init int hpet_mmap_enable(char *str)
350{
351 get_option(str: &str, pint: &hpet_mmap_enabled);
352 pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
353 return 1;
354}
355__setup("hpet_mmap=", hpet_mmap_enable);
356
357static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
358{
359 struct hpet_dev *devp;
360 unsigned long addr;
361
362 if (!hpet_mmap_enabled)
363 return -EACCES;
364
365 devp = file->private_data;
366 addr = devp->hd_hpets->hp_hpet_phys;
367
368 if (addr & (PAGE_SIZE - 1))
369 return -ENOSYS;
370
371 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
372 return vm_iomap_memory(vma, start: addr, PAGE_SIZE);
373}
374#else
375static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
376{
377 return -ENOSYS;
378}
379#endif
380
381static int hpet_fasync(int fd, struct file *file, int on)
382{
383 struct hpet_dev *devp;
384
385 devp = file->private_data;
386
387 if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
388 return 0;
389 else
390 return -EIO;
391}
392
393static int hpet_release(struct inode *inode, struct file *file)
394{
395 struct hpet_dev *devp;
396 struct hpet_timer __iomem *timer;
397 int irq = 0;
398
399 devp = file->private_data;
400 timer = devp->hd_timer;
401
402 spin_lock_irq(lock: &hpet_lock);
403
404 writeq(val: (readq(addr: &timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
405 addr: &timer->hpet_config);
406
407 irq = devp->hd_irq;
408 devp->hd_irq = 0;
409
410 devp->hd_ireqfreq = 0;
411
412 if (devp->hd_flags & HPET_PERIODIC
413 && readq(addr: &timer->hpet_config) & Tn_TYPE_CNF_MASK) {
414 unsigned long v;
415
416 v = readq(addr: &timer->hpet_config);
417 v ^= Tn_TYPE_CNF_MASK;
418 writeq(val: v, addr: &timer->hpet_config);
419 }
420
421 devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
422 spin_unlock_irq(lock: &hpet_lock);
423
424 if (irq)
425 free_irq(irq, devp);
426
427 file->private_data = NULL;
428 return 0;
429}
430
431static int hpet_ioctl_ieon(struct hpet_dev *devp)
432{
433 struct hpet_timer __iomem *timer;
434 struct hpet __iomem *hpet;
435 struct hpets *hpetp;
436 int irq;
437 unsigned long g, v, t, m;
438 unsigned long flags, isr;
439
440 timer = devp->hd_timer;
441 hpet = devp->hd_hpet;
442 hpetp = devp->hd_hpets;
443
444 if (!devp->hd_ireqfreq)
445 return -EIO;
446
447 spin_lock_irq(lock: &hpet_lock);
448
449 if (devp->hd_flags & HPET_IE) {
450 spin_unlock_irq(lock: &hpet_lock);
451 return -EBUSY;
452 }
453
454 devp->hd_flags |= HPET_IE;
455
456 if (readl(addr: &timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
457 devp->hd_flags |= HPET_SHARED_IRQ;
458 spin_unlock_irq(lock: &hpet_lock);
459
460 irq = devp->hd_hdwirq;
461
462 if (irq) {
463 unsigned long irq_flags;
464
465 if (devp->hd_flags & HPET_SHARED_IRQ) {
466 /*
467 * To prevent the interrupt handler from seeing an
468 * unwanted interrupt status bit, program the timer
469 * so that it will not fire in the near future ...
470 */
471 writel(readl(addr: &timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
472 addr: &timer->hpet_config);
473 write_counter(read_counter(&hpet->hpet_mc),
474 &timer->hpet_compare);
475 /* ... and clear any left-over status. */
476 isr = 1 << (devp - devp->hd_hpets->hp_dev);
477 writel(val: isr, addr: &hpet->hpet_isr);
478 }
479
480 sprintf(buf: devp->hd_name, fmt: "hpet%d", (int)(devp - hpetp->hp_dev));
481 irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
482 if (request_irq(irq, handler: hpet_interrupt, flags: irq_flags,
483 name: devp->hd_name, dev: (void *)devp)) {
484 printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
485 irq = 0;
486 }
487 }
488
489 if (irq == 0) {
490 spin_lock_irq(lock: &hpet_lock);
491 devp->hd_flags ^= HPET_IE;
492 spin_unlock_irq(lock: &hpet_lock);
493 return -EIO;
494 }
495
496 devp->hd_irq = irq;
497 t = devp->hd_ireqfreq;
498 v = readq(addr: &timer->hpet_config);
499
500 /* 64-bit comparators are not yet supported through the ioctls,
501 * so force this into 32-bit mode if it supports both modes
502 */
503 g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
504
505 if (devp->hd_flags & HPET_PERIODIC) {
506 g |= Tn_TYPE_CNF_MASK;
507 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
508 writeq(val: v, addr: &timer->hpet_config);
509 local_irq_save(flags);
510
511 /*
512 * NOTE: First we modify the hidden accumulator
513 * register supported by periodic-capable comparators.
514 * We never want to modify the (single) counter; that
515 * would affect all the comparators. The value written
516 * is the counter value when the first interrupt is due.
517 */
518 m = read_counter(&hpet->hpet_mc);
519 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
520 /*
521 * Then we modify the comparator, indicating the period
522 * for subsequent interrupt.
523 */
524 write_counter(t, &timer->hpet_compare);
525 } else {
526 local_irq_save(flags);
527 m = read_counter(&hpet->hpet_mc);
528 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
529 }
530
531 if (devp->hd_flags & HPET_SHARED_IRQ) {
532 isr = 1 << (devp - devp->hd_hpets->hp_dev);
533 writel(val: isr, addr: &hpet->hpet_isr);
534 }
535 writeq(val: g, addr: &timer->hpet_config);
536 local_irq_restore(flags);
537
538 return 0;
539}
540
541/* converts Hz to number of timer ticks */
542static 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 return div64_ul(m, dis);
549}
550
551static int
552hpet_ioctl_common(struct hpet_dev *devp, unsigned int cmd, unsigned long arg,
553 struct hpet_info *info)
554{
555 struct hpet_timer __iomem *timer;
556 struct hpets *hpetp;
557 int err;
558 unsigned long v;
559
560 switch (cmd) {
561 case HPET_IE_OFF:
562 case HPET_INFO:
563 case HPET_EPI:
564 case HPET_DPI:
565 case HPET_IRQFREQ:
566 timer = devp->hd_timer;
567 hpetp = devp->hd_hpets;
568 break;
569 case HPET_IE_ON:
570 return hpet_ioctl_ieon(devp);
571 default:
572 return -EINVAL;
573 }
574
575 err = 0;
576
577 switch (cmd) {
578 case HPET_IE_OFF:
579 if ((devp->hd_flags & HPET_IE) == 0)
580 break;
581 v = readq(addr: &timer->hpet_config);
582 v &= ~Tn_INT_ENB_CNF_MASK;
583 writeq(val: v, addr: &timer->hpet_config);
584 if (devp->hd_irq) {
585 free_irq(devp->hd_irq, devp);
586 devp->hd_irq = 0;
587 }
588 devp->hd_flags ^= HPET_IE;
589 break;
590 case HPET_INFO:
591 {
592 memset(info, 0, sizeof(*info));
593 if (devp->hd_ireqfreq)
594 info->hi_ireqfreq =
595 hpet_time_div(hpets: hpetp, dis: devp->hd_ireqfreq);
596 info->hi_flags =
597 readq(addr: &timer->hpet_config) & Tn_PER_INT_CAP_MASK;
598 info->hi_hpet = hpetp->hp_which;
599 info->hi_timer = devp - hpetp->hp_dev;
600 break;
601 }
602 case HPET_EPI:
603 v = readq(addr: &timer->hpet_config);
604 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
605 err = -ENXIO;
606 break;
607 }
608 devp->hd_flags |= HPET_PERIODIC;
609 break;
610 case HPET_DPI:
611 v = readq(addr: &timer->hpet_config);
612 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
613 err = -ENXIO;
614 break;
615 }
616 if (devp->hd_flags & HPET_PERIODIC &&
617 readq(addr: &timer->hpet_config) & Tn_TYPE_CNF_MASK) {
618 v = readq(addr: &timer->hpet_config);
619 v ^= Tn_TYPE_CNF_MASK;
620 writeq(val: v, addr: &timer->hpet_config);
621 }
622 devp->hd_flags &= ~HPET_PERIODIC;
623 break;
624 case HPET_IRQFREQ:
625 if ((arg > hpet_max_freq) &&
626 !capable(CAP_SYS_RESOURCE)) {
627 err = -EACCES;
628 break;
629 }
630
631 if (!arg) {
632 err = -EINVAL;
633 break;
634 }
635
636 devp->hd_ireqfreq = hpet_time_div(hpets: hpetp, dis: arg);
637 }
638
639 return err;
640}
641
642static long
643hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
644{
645 struct hpet_info info;
646 int err;
647
648 mutex_lock(&hpet_mutex);
649 err = hpet_ioctl_common(devp: file->private_data, cmd, arg, info: &info);
650 mutex_unlock(lock: &hpet_mutex);
651
652 if ((cmd == HPET_INFO) && !err &&
653 (copy_to_user(to: (void __user *)arg, from: &info, n: sizeof(info))))
654 err = -EFAULT;
655
656 return err;
657}
658
659#ifdef CONFIG_COMPAT
660struct compat_hpet_info {
661 compat_ulong_t hi_ireqfreq; /* Hz */
662 compat_ulong_t hi_flags; /* information */
663 unsigned short hi_hpet;
664 unsigned short hi_timer;
665};
666
667/* 32-bit types would lead to different command codes which should be
668 * translated into 64-bit ones before passed to hpet_ioctl_common
669 */
670#define COMPAT_HPET_INFO _IOR('h', 0x03, struct compat_hpet_info)
671#define COMPAT_HPET_IRQFREQ _IOW('h', 0x6, compat_ulong_t)
672
673static long
674hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
675{
676 struct hpet_info info;
677 int err;
678
679 if (cmd == COMPAT_HPET_INFO)
680 cmd = HPET_INFO;
681
682 if (cmd == COMPAT_HPET_IRQFREQ)
683 cmd = HPET_IRQFREQ;
684
685 mutex_lock(&hpet_mutex);
686 err = hpet_ioctl_common(devp: file->private_data, cmd, arg, info: &info);
687 mutex_unlock(lock: &hpet_mutex);
688
689 if ((cmd == HPET_INFO) && !err) {
690 struct compat_hpet_info __user *u = compat_ptr(uptr: arg);
691 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
692 put_user(info.hi_flags, &u->hi_flags) ||
693 put_user(info.hi_hpet, &u->hi_hpet) ||
694 put_user(info.hi_timer, &u->hi_timer))
695 err = -EFAULT;
696 }
697
698 return err;
699}
700#endif
701
702static const struct file_operations hpet_fops = {
703 .owner = THIS_MODULE,
704 .read = hpet_read,
705 .poll = hpet_poll,
706 .unlocked_ioctl = hpet_ioctl,
707#ifdef CONFIG_COMPAT
708 .compat_ioctl = hpet_compat_ioctl,
709#endif
710 .open = hpet_open,
711 .release = hpet_release,
712 .fasync = hpet_fasync,
713 .mmap = hpet_mmap,
714};
715
716static int hpet_is_known(struct hpet_data *hdp)
717{
718 struct hpets *hpetp;
719
720 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
721 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
722 return 1;
723
724 return 0;
725}
726
727static const struct ctl_table hpet_table[] = {
728 {
729 .procname = "max-user-freq",
730 .data = &hpet_max_freq,
731 .maxlen = sizeof(int),
732 .mode = 0644,
733 .proc_handler = proc_dointvec,
734 },
735};
736
737static struct ctl_table_header *sysctl_header;
738
739/*
740 * Adjustment for when arming the timer with
741 * initial conditions. That is, main counter
742 * ticks expired before interrupts are enabled.
743 */
744#define TICK_CALIBRATE (1000UL)
745
746static unsigned long __hpet_calibrate(struct hpets *hpetp)
747{
748 struct hpet_timer __iomem *timer = NULL;
749 unsigned long t, m, count, i, flags, start;
750 struct hpet_dev *devp;
751 int j;
752 struct hpet __iomem *hpet;
753
754 for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
755 if ((devp->hd_flags & HPET_OPEN) == 0) {
756 timer = devp->hd_timer;
757 break;
758 }
759
760 if (!timer)
761 return 0;
762
763 hpet = hpetp->hp_hpet;
764 t = read_counter(&timer->hpet_compare);
765
766 i = 0;
767 count = hpet_time_div(hpets: hpetp, TICK_CALIBRATE);
768
769 local_irq_save(flags);
770
771 start = read_counter(&hpet->hpet_mc);
772
773 do {
774 m = read_counter(&hpet->hpet_mc);
775 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
776 } while (i++, (m - start) < count);
777
778 local_irq_restore(flags);
779
780 return (m - start) / i;
781}
782
783static unsigned long hpet_calibrate(struct hpets *hpetp)
784{
785 unsigned long ret = ~0UL;
786 unsigned long tmp;
787
788 /*
789 * Try to calibrate until return value becomes stable small value.
790 * If SMI interruption occurs in calibration loop, the return value
791 * will be big. This avoids its impact.
792 */
793 for ( ; ; ) {
794 tmp = __hpet_calibrate(hpetp);
795 if (ret <= tmp)
796 break;
797 ret = tmp;
798 }
799
800 return ret;
801}
802
803int hpet_alloc(struct hpet_data *hdp)
804{
805 u64 cap, mcfg;
806 struct hpet_dev *devp;
807 u32 i, ntimer;
808 struct hpets *hpetp;
809 struct hpet __iomem *hpet;
810 static struct hpets *last;
811 u32 period;
812 unsigned long long temp;
813 u32 remainder;
814
815 /*
816 * hpet_alloc can be called by platform dependent code.
817 * If platform dependent code has allocated the hpet that
818 * ACPI has also reported, then we catch it here.
819 */
820 if (hpet_is_known(hdp)) {
821 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
822 __func__);
823 return 0;
824 }
825
826 hpetp = kzalloc(struct_size(hpetp, hp_dev, hdp->hd_nirqs),
827 GFP_KERNEL);
828
829 if (!hpetp)
830 return -ENOMEM;
831
832 hpetp->hp_which = hpet_nhpet++;
833 hpetp->hp_hpet = hdp->hd_address;
834 hpetp->hp_hpet_phys = hdp->hd_phys_address;
835
836 hpetp->hp_ntimer = hdp->hd_nirqs;
837
838 for (i = 0; i < hdp->hd_nirqs; i++)
839 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
840
841 hpet = hpetp->hp_hpet;
842
843 cap = readq(addr: &hpet->hpet_cap);
844
845 ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
846
847 if (hpetp->hp_ntimer != ntimer) {
848 printk(KERN_WARNING "hpet: number irqs doesn't agree"
849 " with number of timers\n");
850 kfree(objp: hpetp);
851 return -ENODEV;
852 }
853
854 if (last)
855 last->hp_next = hpetp;
856 else
857 hpets = hpetp;
858
859 last = hpetp;
860
861 period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
862 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
863 temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
864 temp += period >> 1; /* round */
865 do_div(temp, period);
866 hpetp->hp_tick_freq = temp; /* ticks per second */
867
868 printk(KERN_INFO "hpet%u: at MMIO 0x%lx, IRQ%s",
869 hpetp->hp_which, hdp->hd_phys_address,
870 hpetp->hp_ntimer > 1 ? "s" : "");
871 for (i = 0; i < hpetp->hp_ntimer; i++)
872 printk(KERN_CONT "%s %u", i > 0 ? "," : "", hdp->hd_irq[i]);
873 printk(KERN_CONT "\n");
874
875 temp = hpetp->hp_tick_freq;
876 remainder = do_div(temp, 1000000);
877 printk(KERN_INFO
878 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
879 hpetp->hp_which, hpetp->hp_ntimer,
880 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
881 (unsigned) temp, remainder);
882
883 mcfg = readq(addr: &hpet->hpet_config);
884 if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
885 write_counter(0L, &hpet->hpet_mc);
886 mcfg |= HPET_ENABLE_CNF_MASK;
887 writeq(val: mcfg, addr: &hpet->hpet_config);
888 }
889
890 for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
891 struct hpet_timer __iomem *timer;
892
893 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
894
895 devp->hd_hpets = hpetp;
896 devp->hd_hpet = hpet;
897 devp->hd_timer = timer;
898
899 /*
900 * If the timer was reserved by platform code,
901 * then make timer unavailable for opens.
902 */
903 if (hdp->hd_state & (1 << i)) {
904 devp->hd_flags = HPET_OPEN;
905 continue;
906 }
907
908 init_waitqueue_head(&devp->hd_waitqueue);
909 }
910
911 hpetp->hp_delta = hpet_calibrate(hpetp);
912
913 return 0;
914}
915
916static acpi_status hpet_resources(struct acpi_resource *res, void *data)
917{
918 struct hpet_data *hdp;
919 acpi_status status;
920 struct acpi_resource_address64 addr;
921
922 hdp = data;
923
924 status = acpi_resource_to_address64(resource: res, out: &addr);
925
926 if (ACPI_SUCCESS(status)) {
927 hdp->hd_phys_address = addr.address.minimum;
928 hdp->hd_address = ioremap(offset: addr.address.minimum, size: addr.address.address_length);
929 if (!hdp->hd_address)
930 return AE_ERROR;
931
932 if (hpet_is_known(hdp)) {
933 iounmap(addr: hdp->hd_address);
934 return AE_ALREADY_EXISTS;
935 }
936 } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
937 struct acpi_resource_fixed_memory32 *fixmem32;
938
939 fixmem32 = &res->data.fixed_memory32;
940
941 hdp->hd_phys_address = fixmem32->address;
942 hdp->hd_address = ioremap(offset: fixmem32->address,
943 HPET_RANGE_SIZE);
944 if (!hdp->hd_address)
945 return AE_ERROR;
946
947 if (hpet_is_known(hdp)) {
948 iounmap(addr: hdp->hd_address);
949 return AE_ALREADY_EXISTS;
950 }
951 } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
952 struct acpi_resource_extended_irq *irqp;
953 int i, irq;
954
955 irqp = &res->data.extended_irq;
956
957 for (i = 0; i < irqp->interrupt_count; i++) {
958 if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
959 break;
960
961 irq = acpi_register_gsi(NULL, gsi: irqp->interrupts[i],
962 triggering: irqp->triggering,
963 polarity: irqp->polarity);
964 if (irq < 0)
965 return AE_ERROR;
966
967 hdp->hd_irq[hdp->hd_nirqs] = irq;
968 hdp->hd_nirqs++;
969 }
970 }
971
972 return AE_OK;
973}
974
975static int hpet_acpi_add(struct acpi_device *device)
976{
977 acpi_status result;
978 struct hpet_data data;
979
980 memset(&data, 0, sizeof(data));
981
982 result =
983 acpi_walk_resources(device: device->handle, METHOD_NAME__CRS,
984 user_function: hpet_resources, context: &data);
985
986 if (ACPI_FAILURE(result))
987 return -ENODEV;
988
989 if (!data.hd_address || !data.hd_nirqs) {
990 if (data.hd_address)
991 iounmap(addr: data.hd_address);
992 printk("%s: no address or irqs in _CRS\n", __func__);
993 return -ENODEV;
994 }
995
996 return hpet_alloc(hdp: &data);
997}
998
999static const struct acpi_device_id hpet_device_ids[] = {
1000 {"PNP0103", 0},
1001 {"", 0},
1002};
1003
1004static struct acpi_driver hpet_acpi_driver = {
1005 .name = "hpet",
1006 .ids = hpet_device_ids,
1007 .ops = {
1008 .add = hpet_acpi_add,
1009 },
1010};
1011
1012static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1013
1014static int __init hpet_init(void)
1015{
1016 int result;
1017
1018 result = misc_register(misc: &hpet_misc);
1019 if (result < 0)
1020 return -ENODEV;
1021
1022 sysctl_header = register_sysctl("dev/hpet", hpet_table);
1023
1024 result = acpi_bus_register_driver(&hpet_acpi_driver);
1025 if (result < 0) {
1026 unregister_sysctl_table(table: sysctl_header);
1027 misc_deregister(misc: &hpet_misc);
1028 return result;
1029 }
1030
1031 return 0;
1032}
1033device_initcall(hpet_init);
1034
1035/*
1036MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1037MODULE_LICENSE("GPL");
1038*/
1039

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