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
64 static DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
65 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
66
67 /* A lock for concurrent access by app and isr hpet activity. */
68 static DEFINE_SPINLOCK(hpet_lock);
69
70 #define HPET_DEV_NAME (7)
71
72 struct 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
86 struct 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
97 static 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
hpet_interrupt(int irq,void * data)104 static 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(&devp->hd_hpet->hpet_isr)))
114 return IRQ_NONE;
115
116 spin_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(isr, &devp->hd_hpet->hpet_isr);
154 spin_unlock(&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
hpet_timer_set_irq(struct hpet_dev * devp)163 static 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(&hpet_lock);
170 if (devp->hd_hdwirq) {
171 spin_unlock_irq(&hpet_lock);
172 return;
173 }
174
175 timer = devp->hd_timer;
176
177 /* we prefer level triggered mode */
178 v = readl(&timer->hpet_config);
179 if (!(v & Tn_INT_TYPE_CNF_MASK)) {
180 v |= Tn_INT_TYPE_CNF_MASK;
181 writel(v, &timer->hpet_config);
182 }
183 spin_unlock_irq(&hpet_lock);
184
185 v = (readq(&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, 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(&hpet_lock);
213 v = readl(&timer->hpet_config);
214 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
215 writel(v, &timer->hpet_config);
216 devp->hd_hdwirq = gsi;
217 spin_unlock_irq(&hpet_lock);
218 }
219 return;
220 }
221
hpet_open(struct inode * inode,struct file * file)222 static 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(&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(&hpet_lock);
245 mutex_unlock(&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(&hpet_lock);
253 mutex_unlock(&hpet_mutex);
254
255 hpet_timer_set_irq(devp);
256
257 return 0;
258 }
259
260 static ssize_t
hpet_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)261 hpet_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 (in_compat_syscall()) {
273 if (count < sizeof(compat_ulong_t))
274 return -EINVAL;
275 } else {
276 if (count < sizeof(unsigned long))
277 return -EINVAL;
278 }
279
280 add_wait_queue(&devp->hd_waitqueue, &wait);
281
282 for ( ; ; ) {
283 set_current_state(TASK_INTERRUPTIBLE);
284
285 spin_lock_irq(&hpet_lock);
286 data = devp->hd_irqdata;
287 devp->hd_irqdata = 0;
288 spin_unlock_irq(&hpet_lock);
289
290 if (data) {
291 break;
292 } else if (file->f_flags & O_NONBLOCK) {
293 retval = -EAGAIN;
294 goto out;
295 } else if (signal_pending(current)) {
296 retval = -ERESTARTSYS;
297 goto out;
298 }
299 schedule();
300 }
301
302 if (in_compat_syscall()) {
303 retval = put_user(data, (compat_ulong_t __user *)buf);
304 if (!retval)
305 retval = sizeof(compat_ulong_t);
306 } else {
307 retval = put_user(data, (unsigned long __user *)buf);
308 if (!retval)
309 retval = sizeof(unsigned long);
310 }
311
312 out:
313 __set_current_state(TASK_RUNNING);
314 remove_wait_queue(&devp->hd_waitqueue, &wait);
315
316 return retval;
317 }
318
hpet_poll(struct file * file,poll_table * wait)319 static __poll_t hpet_poll(struct file *file, poll_table * wait)
320 {
321 unsigned long v;
322 struct hpet_dev *devp;
323
324 devp = file->private_data;
325
326 if (!devp->hd_ireqfreq)
327 return 0;
328
329 poll_wait(file, &devp->hd_waitqueue, wait);
330
331 spin_lock_irq(&hpet_lock);
332 v = devp->hd_irqdata;
333 spin_unlock_irq(&hpet_lock);
334
335 if (v != 0)
336 return EPOLLIN | EPOLLRDNORM;
337
338 return 0;
339 }
340
341 #ifdef CONFIG_HPET_MMAP
342 #ifdef CONFIG_HPET_MMAP_DEFAULT
343 static int hpet_mmap_enabled = 1;
344 #else
345 static int hpet_mmap_enabled = 0;
346 #endif
347
hpet_mmap_enable(char * str)348 static __init int hpet_mmap_enable(char *str)
349 {
350 get_option(&str, &hpet_mmap_enabled);
351 pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
352 return 1;
353 }
354 __setup("hpet_mmap=", hpet_mmap_enable);
355
hpet_mmap(struct file * file,struct vm_area_struct * vma)356 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
357 {
358 struct hpet_dev *devp;
359 unsigned long addr;
360
361 if (!hpet_mmap_enabled)
362 return -EACCES;
363
364 devp = file->private_data;
365 addr = devp->hd_hpets->hp_hpet_phys;
366
367 if (addr & (PAGE_SIZE - 1))
368 return -ENOSYS;
369
370 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
371 return vm_iomap_memory(vma, addr, PAGE_SIZE);
372 }
373 #else
hpet_mmap(struct file * file,struct vm_area_struct * vma)374 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
375 {
376 return -ENOSYS;
377 }
378 #endif
379
hpet_fasync(int fd,struct file * file,int on)380 static int hpet_fasync(int fd, struct file *file, int on)
381 {
382 struct hpet_dev *devp;
383
384 devp = file->private_data;
385
386 if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
387 return 0;
388 else
389 return -EIO;
390 }
391
hpet_release(struct inode * inode,struct file * file)392 static int hpet_release(struct inode *inode, struct file *file)
393 {
394 struct hpet_dev *devp;
395 struct hpet_timer __iomem *timer;
396 int irq = 0;
397
398 devp = file->private_data;
399 timer = devp->hd_timer;
400
401 spin_lock_irq(&hpet_lock);
402
403 writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
404 &timer->hpet_config);
405
406 irq = devp->hd_irq;
407 devp->hd_irq = 0;
408
409 devp->hd_ireqfreq = 0;
410
411 if (devp->hd_flags & HPET_PERIODIC
412 && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
413 unsigned long v;
414
415 v = readq(&timer->hpet_config);
416 v ^= Tn_TYPE_CNF_MASK;
417 writeq(v, &timer->hpet_config);
418 }
419
420 devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
421 spin_unlock_irq(&hpet_lock);
422
423 if (irq)
424 free_irq(irq, devp);
425
426 file->private_data = NULL;
427 return 0;
428 }
429
hpet_ioctl_ieon(struct hpet_dev * devp)430 static int hpet_ioctl_ieon(struct hpet_dev *devp)
431 {
432 struct hpet_timer __iomem *timer;
433 struct hpet __iomem *hpet;
434 struct hpets *hpetp;
435 int irq;
436 unsigned long g, v, t, m;
437 unsigned long flags, isr;
438
439 timer = devp->hd_timer;
440 hpet = devp->hd_hpet;
441 hpetp = devp->hd_hpets;
442
443 if (!devp->hd_ireqfreq)
444 return -EIO;
445
446 spin_lock_irq(&hpet_lock);
447
448 if (devp->hd_flags & HPET_IE) {
449 spin_unlock_irq(&hpet_lock);
450 return -EBUSY;
451 }
452
453 devp->hd_flags |= HPET_IE;
454
455 if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
456 devp->hd_flags |= HPET_SHARED_IRQ;
457 spin_unlock_irq(&hpet_lock);
458
459 irq = devp->hd_hdwirq;
460
461 if (irq) {
462 unsigned long irq_flags;
463
464 if (devp->hd_flags & HPET_SHARED_IRQ) {
465 /*
466 * To prevent the interrupt handler from seeing an
467 * unwanted interrupt status bit, program the timer
468 * so that it will not fire in the near future ...
469 */
470 writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
471 &timer->hpet_config);
472 write_counter(read_counter(&hpet->hpet_mc),
473 &timer->hpet_compare);
474 /* ... and clear any left-over status. */
475 isr = 1 << (devp - devp->hd_hpets->hp_dev);
476 writel(isr, &hpet->hpet_isr);
477 }
478
479 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
480 irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
481 if (request_irq(irq, hpet_interrupt, irq_flags,
482 devp->hd_name, (void *)devp)) {
483 printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
484 irq = 0;
485 }
486 }
487
488 if (irq == 0) {
489 spin_lock_irq(&hpet_lock);
490 devp->hd_flags ^= HPET_IE;
491 spin_unlock_irq(&hpet_lock);
492 return -EIO;
493 }
494
495 devp->hd_irq = irq;
496 t = devp->hd_ireqfreq;
497 v = readq(&timer->hpet_config);
498
499 /* 64-bit comparators are not yet supported through the ioctls,
500 * so force this into 32-bit mode if it supports both modes
501 */
502 g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
503
504 if (devp->hd_flags & HPET_PERIODIC) {
505 g |= Tn_TYPE_CNF_MASK;
506 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
507 writeq(v, &timer->hpet_config);
508 local_irq_save(flags);
509
510 /*
511 * NOTE: First we modify the hidden accumulator
512 * register supported by periodic-capable comparators.
513 * We never want to modify the (single) counter; that
514 * would affect all the comparators. The value written
515 * is the counter value when the first interrupt is due.
516 */
517 m = read_counter(&hpet->hpet_mc);
518 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
519 /*
520 * Then we modify the comparator, indicating the period
521 * for subsequent interrupt.
522 */
523 write_counter(t, &timer->hpet_compare);
524 } else {
525 local_irq_save(flags);
526 m = read_counter(&hpet->hpet_mc);
527 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
528 }
529
530 if (devp->hd_flags & HPET_SHARED_IRQ) {
531 isr = 1 << (devp - devp->hd_hpets->hp_dev);
532 writel(isr, &hpet->hpet_isr);
533 }
534 writeq(g, &timer->hpet_config);
535 local_irq_restore(flags);
536
537 return 0;
538 }
539
540 /* converts Hz to number of timer ticks */
hpet_time_div(struct hpets * hpets,unsigned long dis)541 static inline unsigned long hpet_time_div(struct hpets *hpets,
542 unsigned long dis)
543 {
544 unsigned long long m;
545
546 m = hpets->hp_tick_freq + (dis >> 1);
547 return div64_ul(m, dis);
548 }
549
550 static int
hpet_ioctl_common(struct hpet_dev * devp,unsigned int cmd,unsigned long arg,struct hpet_info * info)551 hpet_ioctl_common(struct hpet_dev *devp, unsigned int cmd, unsigned long arg,
552 struct hpet_info *info)
553 {
554 struct hpet_timer __iomem *timer;
555 struct hpets *hpetp;
556 int err;
557 unsigned long v;
558
559 switch (cmd) {
560 case HPET_IE_OFF:
561 case HPET_INFO:
562 case HPET_EPI:
563 case HPET_DPI:
564 case HPET_IRQFREQ:
565 timer = devp->hd_timer;
566 hpetp = devp->hd_hpets;
567 break;
568 case HPET_IE_ON:
569 return hpet_ioctl_ieon(devp);
570 default:
571 return -EINVAL;
572 }
573
574 err = 0;
575
576 switch (cmd) {
577 case HPET_IE_OFF:
578 if ((devp->hd_flags & HPET_IE) == 0)
579 break;
580 v = readq(&timer->hpet_config);
581 v &= ~Tn_INT_ENB_CNF_MASK;
582 writeq(v, &timer->hpet_config);
583 if (devp->hd_irq) {
584 free_irq(devp->hd_irq, devp);
585 devp->hd_irq = 0;
586 }
587 devp->hd_flags ^= HPET_IE;
588 break;
589 case HPET_INFO:
590 {
591 memset(info, 0, sizeof(*info));
592 if (devp->hd_ireqfreq)
593 info->hi_ireqfreq =
594 hpet_time_div(hpetp, devp->hd_ireqfreq);
595 info->hi_flags =
596 readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
597 info->hi_hpet = hpetp->hp_which;
598 info->hi_timer = devp - hpetp->hp_dev;
599 break;
600 }
601 case HPET_EPI:
602 v = readq(&timer->hpet_config);
603 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
604 err = -ENXIO;
605 break;
606 }
607 devp->hd_flags |= HPET_PERIODIC;
608 break;
609 case HPET_DPI:
610 v = readq(&timer->hpet_config);
611 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
612 err = -ENXIO;
613 break;
614 }
615 if (devp->hd_flags & HPET_PERIODIC &&
616 readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
617 v = readq(&timer->hpet_config);
618 v ^= Tn_TYPE_CNF_MASK;
619 writeq(v, &timer->hpet_config);
620 }
621 devp->hd_flags &= ~HPET_PERIODIC;
622 break;
623 case HPET_IRQFREQ:
624 if ((arg > hpet_max_freq) &&
625 !capable(CAP_SYS_RESOURCE)) {
626 err = -EACCES;
627 break;
628 }
629
630 if (!arg) {
631 err = -EINVAL;
632 break;
633 }
634
635 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
636 }
637
638 return err;
639 }
640
641 static long
hpet_ioctl(struct file * file,unsigned int cmd,unsigned long arg)642 hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
643 {
644 struct hpet_info info;
645 int err;
646
647 mutex_lock(&hpet_mutex);
648 err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
649 mutex_unlock(&hpet_mutex);
650
651 if ((cmd == HPET_INFO) && !err &&
652 (copy_to_user((void __user *)arg, &info, sizeof(info))))
653 err = -EFAULT;
654
655 return err;
656 }
657
658 #ifdef CONFIG_COMPAT
659 struct compat_hpet_info {
660 compat_ulong_t hi_ireqfreq; /* Hz */
661 compat_ulong_t hi_flags; /* information */
662 unsigned short hi_hpet;
663 unsigned short hi_timer;
664 };
665
666 /* 32-bit types would lead to different command codes which should be
667 * translated into 64-bit ones before passed to hpet_ioctl_common
668 */
669 #define COMPAT_HPET_INFO _IOR('h', 0x03, struct compat_hpet_info)
670 #define COMPAT_HPET_IRQFREQ _IOW('h', 0x6, compat_ulong_t)
671
672 static long
hpet_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)673 hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
674 {
675 struct hpet_info info;
676 int err;
677
678 if (cmd == COMPAT_HPET_INFO)
679 cmd = HPET_INFO;
680
681 if (cmd == COMPAT_HPET_IRQFREQ)
682 cmd = HPET_IRQFREQ;
683
684 mutex_lock(&hpet_mutex);
685 err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
686 mutex_unlock(&hpet_mutex);
687
688 if ((cmd == HPET_INFO) && !err) {
689 struct compat_hpet_info __user *u = compat_ptr(arg);
690 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
691 put_user(info.hi_flags, &u->hi_flags) ||
692 put_user(info.hi_hpet, &u->hi_hpet) ||
693 put_user(info.hi_timer, &u->hi_timer))
694 err = -EFAULT;
695 }
696
697 return err;
698 }
699 #endif
700
701 static const struct file_operations hpet_fops = {
702 .owner = THIS_MODULE,
703 .read = hpet_read,
704 .poll = hpet_poll,
705 .unlocked_ioctl = hpet_ioctl,
706 #ifdef CONFIG_COMPAT
707 .compat_ioctl = hpet_compat_ioctl,
708 #endif
709 .open = hpet_open,
710 .release = hpet_release,
711 .fasync = hpet_fasync,
712 .mmap = hpet_mmap,
713 };
714
hpet_is_known(struct hpet_data * hdp)715 static int hpet_is_known(struct hpet_data *hdp)
716 {
717 struct hpets *hpetp;
718
719 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
720 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
721 return 1;
722
723 return 0;
724 }
725
726 static struct ctl_table hpet_table[] = {
727 {
728 .procname = "max-user-freq",
729 .data = &hpet_max_freq,
730 .maxlen = sizeof(int),
731 .mode = 0644,
732 .proc_handler = proc_dointvec,
733 },
734 };
735
736 static struct ctl_table_header *sysctl_header;
737
738 /*
739 * Adjustment for when arming the timer with
740 * initial conditions. That is, main counter
741 * ticks expired before interrupts are enabled.
742 */
743 #define TICK_CALIBRATE (1000UL)
744
__hpet_calibrate(struct hpets * hpetp)745 static unsigned long __hpet_calibrate(struct hpets *hpetp)
746 {
747 struct hpet_timer __iomem *timer = NULL;
748 unsigned long t, m, count, i, flags, start;
749 struct hpet_dev *devp;
750 int j;
751 struct hpet __iomem *hpet;
752
753 for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
754 if ((devp->hd_flags & HPET_OPEN) == 0) {
755 timer = devp->hd_timer;
756 break;
757 }
758
759 if (!timer)
760 return 0;
761
762 hpet = hpetp->hp_hpet;
763 t = read_counter(&timer->hpet_compare);
764
765 i = 0;
766 count = hpet_time_div(hpetp, TICK_CALIBRATE);
767
768 local_irq_save(flags);
769
770 start = read_counter(&hpet->hpet_mc);
771
772 do {
773 m = read_counter(&hpet->hpet_mc);
774 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
775 } while (i++, (m - start) < count);
776
777 local_irq_restore(flags);
778
779 return (m - start) / i;
780 }
781
hpet_calibrate(struct hpets * hpetp)782 static unsigned long hpet_calibrate(struct hpets *hpetp)
783 {
784 unsigned long ret = ~0UL;
785 unsigned long tmp;
786
787 /*
788 * Try to calibrate until return value becomes stable small value.
789 * If SMI interruption occurs in calibration loop, the return value
790 * will be big. This avoids its impact.
791 */
792 for ( ; ; ) {
793 tmp = __hpet_calibrate(hpetp);
794 if (ret <= tmp)
795 break;
796 ret = tmp;
797 }
798
799 return ret;
800 }
801
hpet_alloc(struct hpet_data * hdp)802 int hpet_alloc(struct hpet_data *hdp)
803 {
804 u64 cap, mcfg;
805 struct hpet_dev *devp;
806 u32 i, ntimer;
807 struct hpets *hpetp;
808 struct hpet __iomem *hpet;
809 static struct hpets *last;
810 u32 period;
811 unsigned long long temp;
812 u32 remainder;
813
814 /*
815 * hpet_alloc can be called by platform dependent code.
816 * If platform dependent code has allocated the hpet that
817 * ACPI has also reported, then we catch it here.
818 */
819 if (hpet_is_known(hdp)) {
820 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
821 __func__);
822 return 0;
823 }
824
825 hpetp = kzalloc(struct_size(hpetp, hp_dev, hdp->hd_nirqs),
826 GFP_KERNEL);
827
828 if (!hpetp)
829 return -ENOMEM;
830
831 hpetp->hp_which = hpet_nhpet++;
832 hpetp->hp_hpet = hdp->hd_address;
833 hpetp->hp_hpet_phys = hdp->hd_phys_address;
834
835 hpetp->hp_ntimer = hdp->hd_nirqs;
836
837 for (i = 0; i < hdp->hd_nirqs; i++)
838 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
839
840 hpet = hpetp->hp_hpet;
841
842 cap = readq(&hpet->hpet_cap);
843
844 ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
845
846 if (hpetp->hp_ntimer != ntimer) {
847 printk(KERN_WARNING "hpet: number irqs doesn't agree"
848 " with number of timers\n");
849 kfree(hpetp);
850 return -ENODEV;
851 }
852
853 if (last)
854 last->hp_next = hpetp;
855 else
856 hpets = hpetp;
857
858 last = hpetp;
859
860 period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
861 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
862 temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
863 temp += period >> 1; /* round */
864 do_div(temp, period);
865 hpetp->hp_tick_freq = temp; /* ticks per second */
866
867 printk(KERN_INFO "hpet%u: at MMIO 0x%lx, IRQ%s",
868 hpetp->hp_which, hdp->hd_phys_address,
869 hpetp->hp_ntimer > 1 ? "s" : "");
870 for (i = 0; i < hpetp->hp_ntimer; i++)
871 printk(KERN_CONT "%s %u", i > 0 ? "," : "", hdp->hd_irq[i]);
872 printk(KERN_CONT "\n");
873
874 temp = hpetp->hp_tick_freq;
875 remainder = do_div(temp, 1000000);
876 printk(KERN_INFO
877 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
878 hpetp->hp_which, hpetp->hp_ntimer,
879 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
880 (unsigned) temp, remainder);
881
882 mcfg = readq(&hpet->hpet_config);
883 if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
884 write_counter(0L, &hpet->hpet_mc);
885 mcfg |= HPET_ENABLE_CNF_MASK;
886 writeq(mcfg, &hpet->hpet_config);
887 }
888
889 for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
890 struct hpet_timer __iomem *timer;
891
892 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
893
894 devp->hd_hpets = hpetp;
895 devp->hd_hpet = hpet;
896 devp->hd_timer = timer;
897
898 /*
899 * If the timer was reserved by platform code,
900 * then make timer unavailable for opens.
901 */
902 if (hdp->hd_state & (1 << i)) {
903 devp->hd_flags = HPET_OPEN;
904 continue;
905 }
906
907 init_waitqueue_head(&devp->hd_waitqueue);
908 }
909
910 hpetp->hp_delta = hpet_calibrate(hpetp);
911
912 return 0;
913 }
914
hpet_resources(struct acpi_resource * res,void * data)915 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
916 {
917 struct hpet_data *hdp;
918 acpi_status status;
919 struct acpi_resource_address64 addr;
920
921 hdp = data;
922
923 status = acpi_resource_to_address64(res, &addr);
924
925 if (ACPI_SUCCESS(status)) {
926 hdp->hd_phys_address = addr.address.minimum;
927 hdp->hd_address = ioremap(addr.address.minimum, addr.address.address_length);
928 if (!hdp->hd_address)
929 return AE_ERROR;
930
931 if (hpet_is_known(hdp)) {
932 iounmap(hdp->hd_address);
933 return AE_ALREADY_EXISTS;
934 }
935 } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
936 struct acpi_resource_fixed_memory32 *fixmem32;
937
938 fixmem32 = &res->data.fixed_memory32;
939
940 hdp->hd_phys_address = fixmem32->address;
941 hdp->hd_address = ioremap(fixmem32->address,
942 HPET_RANGE_SIZE);
943 if (!hdp->hd_address)
944 return AE_ERROR;
945
946 if (hpet_is_known(hdp)) {
947 iounmap(hdp->hd_address);
948 return AE_ALREADY_EXISTS;
949 }
950 } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
951 struct acpi_resource_extended_irq *irqp;
952 int i, irq;
953
954 irqp = &res->data.extended_irq;
955
956 for (i = 0; i < irqp->interrupt_count; i++) {
957 if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
958 break;
959
960 irq = acpi_register_gsi(NULL, irqp->interrupts[i],
961 irqp->triggering,
962 irqp->polarity);
963 if (irq < 0)
964 return AE_ERROR;
965
966 hdp->hd_irq[hdp->hd_nirqs] = irq;
967 hdp->hd_nirqs++;
968 }
969 }
970
971 return AE_OK;
972 }
973
hpet_acpi_add(struct acpi_device * device)974 static int hpet_acpi_add(struct acpi_device *device)
975 {
976 acpi_status result;
977 struct hpet_data data;
978
979 memset(&data, 0, sizeof(data));
980
981 result =
982 acpi_walk_resources(device->handle, METHOD_NAME__CRS,
983 hpet_resources, &data);
984
985 if (ACPI_FAILURE(result))
986 return -ENODEV;
987
988 if (!data.hd_address || !data.hd_nirqs) {
989 if (data.hd_address)
990 iounmap(data.hd_address);
991 printk("%s: no address or irqs in _CRS\n", __func__);
992 return -ENODEV;
993 }
994
995 return hpet_alloc(&data);
996 }
997
998 static const struct acpi_device_id hpet_device_ids[] = {
999 {"PNP0103", 0},
1000 {"", 0},
1001 };
1002
1003 static struct acpi_driver hpet_acpi_driver = {
1004 .name = "hpet",
1005 .ids = hpet_device_ids,
1006 .ops = {
1007 .add = hpet_acpi_add,
1008 },
1009 };
1010
1011 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1012
hpet_init(void)1013 static int __init hpet_init(void)
1014 {
1015 int result;
1016
1017 result = misc_register(&hpet_misc);
1018 if (result < 0)
1019 return -ENODEV;
1020
1021 sysctl_header = register_sysctl("dev/hpet", hpet_table);
1022
1023 result = acpi_bus_register_driver(&hpet_acpi_driver);
1024 if (result < 0) {
1025 if (sysctl_header)
1026 unregister_sysctl_table(sysctl_header);
1027 misc_deregister(&hpet_misc);
1028 return result;
1029 }
1030
1031 return 0;
1032 }
1033 device_initcall(hpet_init);
1034
1035 /*
1036 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1037 MODULE_LICENSE("GPL");
1038 */
1039