xref: /openbmc/linux/drivers/char/hpet.c (revision c21b37f6)
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/interrupt.h>
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/types.h>
18 #include <linux/miscdevice.h>
19 #include <linux/major.h>
20 #include <linux/ioport.h>
21 #include <linux/fcntl.h>
22 #include <linux/init.h>
23 #include <linux/poll.h>
24 #include <linux/mm.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 #include <linux/clocksource.h>
33 
34 #include <asm/current.h>
35 #include <asm/uaccess.h>
36 #include <asm/system.h>
37 #include <asm/io.h>
38 #include <asm/irq.h>
39 #include <asm/div64.h>
40 
41 #include <linux/acpi.h>
42 #include <acpi/acpi_bus.h>
43 #include <linux/hpet.h>
44 
45 /*
46  * The High Precision Event Timer driver.
47  * This driver is closely modelled after the rtc.c driver.
48  * http://www.intel.com/hardwaredesign/hpetspec.htm
49  */
50 #define	HPET_USER_FREQ	(64)
51 #define	HPET_DRIFT	(500)
52 
53 #define HPET_RANGE_SIZE		1024	/* from HPET spec */
54 
55 #if BITS_PER_LONG == 64
56 #define	write_counter(V, MC)	writeq(V, MC)
57 #define	read_counter(MC)	readq(MC)
58 #else
59 #define	write_counter(V, MC)	writel(V, MC)
60 #define	read_counter(MC)	readl(MC)
61 #endif
62 
63 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
64 
65 static void __iomem *hpet_mctr;
66 
67 static cycle_t read_hpet(void)
68 {
69 	return (cycle_t)read_counter((void __iomem *)hpet_mctr);
70 }
71 
72 static struct clocksource clocksource_hpet = {
73         .name           = "hpet",
74         .rating         = 250,
75         .read           = read_hpet,
76         .mask           = CLOCKSOURCE_MASK(64),
77         .mult           = 0, /*to be caluclated*/
78         .shift          = 10,
79         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
80 };
81 static struct clocksource *hpet_clocksource;
82 
83 /* A lock for concurrent access by app and isr hpet activity. */
84 static DEFINE_SPINLOCK(hpet_lock);
85 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
86 static DEFINE_SPINLOCK(hpet_task_lock);
87 
88 #define	HPET_DEV_NAME	(7)
89 
90 struct hpet_dev {
91 	struct hpets *hd_hpets;
92 	struct hpet __iomem *hd_hpet;
93 	struct hpet_timer __iomem *hd_timer;
94 	unsigned long hd_ireqfreq;
95 	unsigned long hd_irqdata;
96 	wait_queue_head_t hd_waitqueue;
97 	struct fasync_struct *hd_async_queue;
98 	struct hpet_task *hd_task;
99 	unsigned int hd_flags;
100 	unsigned int hd_irq;
101 	unsigned int hd_hdwirq;
102 	char hd_name[HPET_DEV_NAME];
103 };
104 
105 struct hpets {
106 	struct hpets *hp_next;
107 	struct hpet __iomem *hp_hpet;
108 	unsigned long hp_hpet_phys;
109 	struct clocksource *hp_clocksource;
110 	unsigned long long hp_tick_freq;
111 	unsigned long hp_delta;
112 	unsigned int hp_ntimer;
113 	unsigned int hp_which;
114 	struct hpet_dev hp_dev[1];
115 };
116 
117 static struct hpets *hpets;
118 
119 #define	HPET_OPEN		0x0001
120 #define	HPET_IE			0x0002	/* interrupt enabled */
121 #define	HPET_PERIODIC		0x0004
122 #define	HPET_SHARED_IRQ		0x0008
123 
124 
125 #ifndef readq
126 static inline unsigned long long readq(void __iomem *addr)
127 {
128 	return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
129 }
130 #endif
131 
132 #ifndef writeq
133 static inline void writeq(unsigned long long v, void __iomem *addr)
134 {
135 	writel(v & 0xffffffff, addr);
136 	writel(v >> 32, addr + 4);
137 }
138 #endif
139 
140 static irqreturn_t hpet_interrupt(int irq, void *data)
141 {
142 	struct hpet_dev *devp;
143 	unsigned long isr;
144 
145 	devp = data;
146 	isr = 1 << (devp - devp->hd_hpets->hp_dev);
147 
148 	if ((devp->hd_flags & HPET_SHARED_IRQ) &&
149 	    !(isr & readl(&devp->hd_hpet->hpet_isr)))
150 		return IRQ_NONE;
151 
152 	spin_lock(&hpet_lock);
153 	devp->hd_irqdata++;
154 
155 	/*
156 	 * For non-periodic timers, increment the accumulator.
157 	 * This has the effect of treating non-periodic like periodic.
158 	 */
159 	if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
160 		unsigned long m, t;
161 
162 		t = devp->hd_ireqfreq;
163 		m = read_counter(&devp->hd_hpet->hpet_mc);
164 		write_counter(t + m + devp->hd_hpets->hp_delta,
165 			      &devp->hd_timer->hpet_compare);
166 	}
167 
168 	if (devp->hd_flags & HPET_SHARED_IRQ)
169 		writel(isr, &devp->hd_hpet->hpet_isr);
170 	spin_unlock(&hpet_lock);
171 
172 	spin_lock(&hpet_task_lock);
173 	if (devp->hd_task)
174 		devp->hd_task->ht_func(devp->hd_task->ht_data);
175 	spin_unlock(&hpet_task_lock);
176 
177 	wake_up_interruptible(&devp->hd_waitqueue);
178 
179 	kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
180 
181 	return IRQ_HANDLED;
182 }
183 
184 static int hpet_open(struct inode *inode, struct file *file)
185 {
186 	struct hpet_dev *devp;
187 	struct hpets *hpetp;
188 	int i;
189 
190 	if (file->f_mode & FMODE_WRITE)
191 		return -EINVAL;
192 
193 	spin_lock_irq(&hpet_lock);
194 
195 	for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
196 		for (i = 0; i < hpetp->hp_ntimer; i++)
197 			if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
198 			    || hpetp->hp_dev[i].hd_task)
199 				continue;
200 			else {
201 				devp = &hpetp->hp_dev[i];
202 				break;
203 			}
204 
205 	if (!devp) {
206 		spin_unlock_irq(&hpet_lock);
207 		return -EBUSY;
208 	}
209 
210 	file->private_data = devp;
211 	devp->hd_irqdata = 0;
212 	devp->hd_flags |= HPET_OPEN;
213 	spin_unlock_irq(&hpet_lock);
214 
215 	return 0;
216 }
217 
218 static ssize_t
219 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
220 {
221 	DECLARE_WAITQUEUE(wait, current);
222 	unsigned long data;
223 	ssize_t retval;
224 	struct hpet_dev *devp;
225 
226 	devp = file->private_data;
227 	if (!devp->hd_ireqfreq)
228 		return -EIO;
229 
230 	if (count < sizeof(unsigned long))
231 		return -EINVAL;
232 
233 	add_wait_queue(&devp->hd_waitqueue, &wait);
234 
235 	for ( ; ; ) {
236 		set_current_state(TASK_INTERRUPTIBLE);
237 
238 		spin_lock_irq(&hpet_lock);
239 		data = devp->hd_irqdata;
240 		devp->hd_irqdata = 0;
241 		spin_unlock_irq(&hpet_lock);
242 
243 		if (data)
244 			break;
245 		else if (file->f_flags & O_NONBLOCK) {
246 			retval = -EAGAIN;
247 			goto out;
248 		} else if (signal_pending(current)) {
249 			retval = -ERESTARTSYS;
250 			goto out;
251 		}
252 		schedule();
253 	}
254 
255 	retval = put_user(data, (unsigned long __user *)buf);
256 	if (!retval)
257 		retval = sizeof(unsigned long);
258 out:
259 	__set_current_state(TASK_RUNNING);
260 	remove_wait_queue(&devp->hd_waitqueue, &wait);
261 
262 	return retval;
263 }
264 
265 static unsigned int hpet_poll(struct file *file, poll_table * wait)
266 {
267 	unsigned long v;
268 	struct hpet_dev *devp;
269 
270 	devp = file->private_data;
271 
272 	if (!devp->hd_ireqfreq)
273 		return 0;
274 
275 	poll_wait(file, &devp->hd_waitqueue, wait);
276 
277 	spin_lock_irq(&hpet_lock);
278 	v = devp->hd_irqdata;
279 	spin_unlock_irq(&hpet_lock);
280 
281 	if (v != 0)
282 		return POLLIN | POLLRDNORM;
283 
284 	return 0;
285 }
286 
287 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
288 {
289 #ifdef	CONFIG_HPET_MMAP
290 	struct hpet_dev *devp;
291 	unsigned long addr;
292 
293 	if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
294 		return -EINVAL;
295 
296 	devp = file->private_data;
297 	addr = devp->hd_hpets->hp_hpet_phys;
298 
299 	if (addr & (PAGE_SIZE - 1))
300 		return -ENOSYS;
301 
302 	vma->vm_flags |= VM_IO;
303 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
304 
305 	if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
306 					PAGE_SIZE, vma->vm_page_prot)) {
307 		printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
308 			__FUNCTION__);
309 		return -EAGAIN;
310 	}
311 
312 	return 0;
313 #else
314 	return -ENOSYS;
315 #endif
316 }
317 
318 static int hpet_fasync(int fd, struct file *file, int on)
319 {
320 	struct hpet_dev *devp;
321 
322 	devp = file->private_data;
323 
324 	if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
325 		return 0;
326 	else
327 		return -EIO;
328 }
329 
330 static int hpet_release(struct inode *inode, struct file *file)
331 {
332 	struct hpet_dev *devp;
333 	struct hpet_timer __iomem *timer;
334 	int irq = 0;
335 
336 	devp = file->private_data;
337 	timer = devp->hd_timer;
338 
339 	spin_lock_irq(&hpet_lock);
340 
341 	writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
342 	       &timer->hpet_config);
343 
344 	irq = devp->hd_irq;
345 	devp->hd_irq = 0;
346 
347 	devp->hd_ireqfreq = 0;
348 
349 	if (devp->hd_flags & HPET_PERIODIC
350 	    && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
351 		unsigned long v;
352 
353 		v = readq(&timer->hpet_config);
354 		v ^= Tn_TYPE_CNF_MASK;
355 		writeq(v, &timer->hpet_config);
356 	}
357 
358 	devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
359 	spin_unlock_irq(&hpet_lock);
360 
361 	if (irq)
362 		free_irq(irq, devp);
363 
364 	if (file->f_flags & FASYNC)
365 		hpet_fasync(-1, file, 0);
366 
367 	file->private_data = NULL;
368 	return 0;
369 }
370 
371 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
372 
373 static int
374 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
375 	   unsigned long arg)
376 {
377 	struct hpet_dev *devp;
378 
379 	devp = file->private_data;
380 	return hpet_ioctl_common(devp, cmd, arg, 0);
381 }
382 
383 static int hpet_ioctl_ieon(struct hpet_dev *devp)
384 {
385 	struct hpet_timer __iomem *timer;
386 	struct hpet __iomem *hpet;
387 	struct hpets *hpetp;
388 	int irq;
389 	unsigned long g, v, t, m;
390 	unsigned long flags, isr;
391 
392 	timer = devp->hd_timer;
393 	hpet = devp->hd_hpet;
394 	hpetp = devp->hd_hpets;
395 
396 	if (!devp->hd_ireqfreq)
397 		return -EIO;
398 
399 	spin_lock_irq(&hpet_lock);
400 
401 	if (devp->hd_flags & HPET_IE) {
402 		spin_unlock_irq(&hpet_lock);
403 		return -EBUSY;
404 	}
405 
406 	devp->hd_flags |= HPET_IE;
407 
408 	if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
409 		devp->hd_flags |= HPET_SHARED_IRQ;
410 	spin_unlock_irq(&hpet_lock);
411 
412 	irq = devp->hd_hdwirq;
413 
414 	if (irq) {
415 		unsigned long irq_flags;
416 
417 		sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
418 		irq_flags = devp->hd_flags & HPET_SHARED_IRQ
419 						? IRQF_SHARED : IRQF_DISABLED;
420 		if (request_irq(irq, hpet_interrupt, irq_flags,
421 				devp->hd_name, (void *)devp)) {
422 			printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
423 			irq = 0;
424 		}
425 	}
426 
427 	if (irq == 0) {
428 		spin_lock_irq(&hpet_lock);
429 		devp->hd_flags ^= HPET_IE;
430 		spin_unlock_irq(&hpet_lock);
431 		return -EIO;
432 	}
433 
434 	devp->hd_irq = irq;
435 	t = devp->hd_ireqfreq;
436 	v = readq(&timer->hpet_config);
437 	g = v | Tn_INT_ENB_CNF_MASK;
438 
439 	if (devp->hd_flags & HPET_PERIODIC) {
440 		write_counter(t, &timer->hpet_compare);
441 		g |= Tn_TYPE_CNF_MASK;
442 		v |= Tn_TYPE_CNF_MASK;
443 		writeq(v, &timer->hpet_config);
444 		v |= Tn_VAL_SET_CNF_MASK;
445 		writeq(v, &timer->hpet_config);
446 		local_irq_save(flags);
447 		m = read_counter(&hpet->hpet_mc);
448 		write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
449 	} else {
450 		local_irq_save(flags);
451 		m = read_counter(&hpet->hpet_mc);
452 		write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
453 	}
454 
455 	if (devp->hd_flags & HPET_SHARED_IRQ) {
456 		isr = 1 << (devp - devp->hd_hpets->hp_dev);
457 		writel(isr, &hpet->hpet_isr);
458 	}
459 	writeq(g, &timer->hpet_config);
460 	local_irq_restore(flags);
461 
462 	return 0;
463 }
464 
465 /* converts Hz to number of timer ticks */
466 static inline unsigned long hpet_time_div(struct hpets *hpets,
467 					  unsigned long dis)
468 {
469 	unsigned long long m;
470 
471 	m = hpets->hp_tick_freq + (dis >> 1);
472 	do_div(m, dis);
473 	return (unsigned long)m;
474 }
475 
476 static int
477 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
478 {
479 	struct hpet_timer __iomem *timer;
480 	struct hpet __iomem *hpet;
481 	struct hpets *hpetp;
482 	int err;
483 	unsigned long v;
484 
485 	switch (cmd) {
486 	case HPET_IE_OFF:
487 	case HPET_INFO:
488 	case HPET_EPI:
489 	case HPET_DPI:
490 	case HPET_IRQFREQ:
491 		timer = devp->hd_timer;
492 		hpet = devp->hd_hpet;
493 		hpetp = devp->hd_hpets;
494 		break;
495 	case HPET_IE_ON:
496 		return hpet_ioctl_ieon(devp);
497 	default:
498 		return -EINVAL;
499 	}
500 
501 	err = 0;
502 
503 	switch (cmd) {
504 	case HPET_IE_OFF:
505 		if ((devp->hd_flags & HPET_IE) == 0)
506 			break;
507 		v = readq(&timer->hpet_config);
508 		v &= ~Tn_INT_ENB_CNF_MASK;
509 		writeq(v, &timer->hpet_config);
510 		if (devp->hd_irq) {
511 			free_irq(devp->hd_irq, devp);
512 			devp->hd_irq = 0;
513 		}
514 		devp->hd_flags ^= HPET_IE;
515 		break;
516 	case HPET_INFO:
517 		{
518 			struct hpet_info info;
519 
520 			if (devp->hd_ireqfreq)
521 				info.hi_ireqfreq =
522 					hpet_time_div(hpetp, devp->hd_ireqfreq);
523 			else
524 				info.hi_ireqfreq = 0;
525 			info.hi_flags =
526 			    readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
527 			info.hi_hpet = hpetp->hp_which;
528 			info.hi_timer = devp - hpetp->hp_dev;
529 			if (kernel)
530 				memcpy((void *)arg, &info, sizeof(info));
531 			else
532 				if (copy_to_user((void __user *)arg, &info,
533 						 sizeof(info)))
534 					err = -EFAULT;
535 			break;
536 		}
537 	case HPET_EPI:
538 		v = readq(&timer->hpet_config);
539 		if ((v & Tn_PER_INT_CAP_MASK) == 0) {
540 			err = -ENXIO;
541 			break;
542 		}
543 		devp->hd_flags |= HPET_PERIODIC;
544 		break;
545 	case HPET_DPI:
546 		v = readq(&timer->hpet_config);
547 		if ((v & Tn_PER_INT_CAP_MASK) == 0) {
548 			err = -ENXIO;
549 			break;
550 		}
551 		if (devp->hd_flags & HPET_PERIODIC &&
552 		    readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
553 			v = readq(&timer->hpet_config);
554 			v ^= Tn_TYPE_CNF_MASK;
555 			writeq(v, &timer->hpet_config);
556 		}
557 		devp->hd_flags &= ~HPET_PERIODIC;
558 		break;
559 	case HPET_IRQFREQ:
560 		if (!kernel && (arg > hpet_max_freq) &&
561 		    !capable(CAP_SYS_RESOURCE)) {
562 			err = -EACCES;
563 			break;
564 		}
565 
566 		if (!arg) {
567 			err = -EINVAL;
568 			break;
569 		}
570 
571 		devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
572 	}
573 
574 	return err;
575 }
576 
577 static const struct file_operations hpet_fops = {
578 	.owner = THIS_MODULE,
579 	.llseek = no_llseek,
580 	.read = hpet_read,
581 	.poll = hpet_poll,
582 	.ioctl = hpet_ioctl,
583 	.open = hpet_open,
584 	.release = hpet_release,
585 	.fasync = hpet_fasync,
586 	.mmap = hpet_mmap,
587 };
588 
589 static int hpet_is_known(struct hpet_data *hdp)
590 {
591 	struct hpets *hpetp;
592 
593 	for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
594 		if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
595 			return 1;
596 
597 	return 0;
598 }
599 
600 EXPORT_SYMBOL(hpet_alloc);
601 EXPORT_SYMBOL(hpet_register);
602 EXPORT_SYMBOL(hpet_unregister);
603 EXPORT_SYMBOL(hpet_control);
604 
605 int hpet_register(struct hpet_task *tp, int periodic)
606 {
607 	unsigned int i;
608 	u64 mask;
609 	struct hpet_timer __iomem *timer;
610 	struct hpet_dev *devp;
611 	struct hpets *hpetp;
612 
613 	switch (periodic) {
614 	case 1:
615 		mask = Tn_PER_INT_CAP_MASK;
616 		break;
617 	case 0:
618 		mask = 0;
619 		break;
620 	default:
621 		return -EINVAL;
622 	}
623 
624 	tp->ht_opaque = NULL;
625 
626 	spin_lock_irq(&hpet_task_lock);
627 	spin_lock(&hpet_lock);
628 
629 	for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
630 		for (timer = hpetp->hp_hpet->hpet_timers, i = 0;
631 		     i < hpetp->hp_ntimer; i++, timer++) {
632 			if ((readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK)
633 			    != mask)
634 				continue;
635 
636 			devp = &hpetp->hp_dev[i];
637 
638 			if (devp->hd_flags & HPET_OPEN || devp->hd_task) {
639 				devp = NULL;
640 				continue;
641 			}
642 
643 			tp->ht_opaque = devp;
644 			devp->hd_task = tp;
645 			break;
646 		}
647 
648 	spin_unlock(&hpet_lock);
649 	spin_unlock_irq(&hpet_task_lock);
650 
651 	if (tp->ht_opaque)
652 		return 0;
653 	else
654 		return -EBUSY;
655 }
656 
657 static inline int hpet_tpcheck(struct hpet_task *tp)
658 {
659 	struct hpet_dev *devp;
660 	struct hpets *hpetp;
661 
662 	devp = tp->ht_opaque;
663 
664 	if (!devp)
665 		return -ENXIO;
666 
667 	for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
668 		if (devp >= hpetp->hp_dev
669 		    && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
670 		    && devp->hd_hpet == hpetp->hp_hpet)
671 			return 0;
672 
673 	return -ENXIO;
674 }
675 
676 int hpet_unregister(struct hpet_task *tp)
677 {
678 	struct hpet_dev *devp;
679 	struct hpet_timer __iomem *timer;
680 	int err;
681 
682 	if ((err = hpet_tpcheck(tp)))
683 		return err;
684 
685 	spin_lock_irq(&hpet_task_lock);
686 	spin_lock(&hpet_lock);
687 
688 	devp = tp->ht_opaque;
689 	if (devp->hd_task != tp) {
690 		spin_unlock(&hpet_lock);
691 		spin_unlock_irq(&hpet_task_lock);
692 		return -ENXIO;
693 	}
694 
695 	timer = devp->hd_timer;
696 	writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
697 	       &timer->hpet_config);
698 	devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
699 	devp->hd_task = NULL;
700 	spin_unlock(&hpet_lock);
701 	spin_unlock_irq(&hpet_task_lock);
702 
703 	return 0;
704 }
705 
706 int hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
707 {
708 	struct hpet_dev *devp;
709 	int err;
710 
711 	if ((err = hpet_tpcheck(tp)))
712 		return err;
713 
714 	spin_lock_irq(&hpet_lock);
715 	devp = tp->ht_opaque;
716 	if (devp->hd_task != tp) {
717 		spin_unlock_irq(&hpet_lock);
718 		return -ENXIO;
719 	}
720 	spin_unlock_irq(&hpet_lock);
721 	return hpet_ioctl_common(devp, cmd, arg, 1);
722 }
723 
724 static ctl_table hpet_table[] = {
725 	{
726 	 .ctl_name = CTL_UNNUMBERED,
727 	 .procname = "max-user-freq",
728 	 .data = &hpet_max_freq,
729 	 .maxlen = sizeof(int),
730 	 .mode = 0644,
731 	 .proc_handler = &proc_dointvec,
732 	 },
733 	{.ctl_name = 0}
734 };
735 
736 static ctl_table hpet_root[] = {
737 	{
738 	 .ctl_name = CTL_UNNUMBERED,
739 	 .procname = "hpet",
740 	 .maxlen = 0,
741 	 .mode = 0555,
742 	 .child = hpet_table,
743 	 },
744 	{.ctl_name = 0}
745 };
746 
747 static ctl_table dev_root[] = {
748 	{
749 	 .ctl_name = CTL_DEV,
750 	 .procname = "dev",
751 	 .maxlen = 0,
752 	 .mode = 0555,
753 	 .child = hpet_root,
754 	 },
755 	{.ctl_name = 0}
756 };
757 
758 static struct ctl_table_header *sysctl_header;
759 
760 /*
761  * Adjustment for when arming the timer with
762  * initial conditions.  That is, main counter
763  * ticks expired before interrupts are enabled.
764  */
765 #define	TICK_CALIBRATE	(1000UL)
766 
767 static unsigned long hpet_calibrate(struct hpets *hpetp)
768 {
769 	struct hpet_timer __iomem *timer = NULL;
770 	unsigned long t, m, count, i, flags, start;
771 	struct hpet_dev *devp;
772 	int j;
773 	struct hpet __iomem *hpet;
774 
775 	for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
776 		if ((devp->hd_flags & HPET_OPEN) == 0) {
777 			timer = devp->hd_timer;
778 			break;
779 		}
780 
781 	if (!timer)
782 		return 0;
783 
784 	hpet = hpetp->hp_hpet;
785 	t = read_counter(&timer->hpet_compare);
786 
787 	i = 0;
788 	count = hpet_time_div(hpetp, TICK_CALIBRATE);
789 
790 	local_irq_save(flags);
791 
792 	start = read_counter(&hpet->hpet_mc);
793 
794 	do {
795 		m = read_counter(&hpet->hpet_mc);
796 		write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
797 	} while (i++, (m - start) < count);
798 
799 	local_irq_restore(flags);
800 
801 	return (m - start) / i;
802 }
803 
804 int hpet_alloc(struct hpet_data *hdp)
805 {
806 	u64 cap, mcfg;
807 	struct hpet_dev *devp;
808 	u32 i, ntimer;
809 	struct hpets *hpetp;
810 	size_t siz;
811 	struct hpet __iomem *hpet;
812 	static struct hpets *last = NULL;
813 	unsigned long period;
814 	unsigned long long temp;
815 
816 	/*
817 	 * hpet_alloc can be called by platform dependent code.
818 	 * If platform dependent code has allocated the hpet that
819 	 * ACPI has also reported, then we catch it here.
820 	 */
821 	if (hpet_is_known(hdp)) {
822 		printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
823 			__FUNCTION__);
824 		return 0;
825 	}
826 
827 	siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
828 				      sizeof(struct hpet_dev));
829 
830 	hpetp = kzalloc(siz, GFP_KERNEL);
831 
832 	if (!hpetp)
833 		return -ENOMEM;
834 
835 	hpetp->hp_which = hpet_nhpet++;
836 	hpetp->hp_hpet = hdp->hd_address;
837 	hpetp->hp_hpet_phys = hdp->hd_phys_address;
838 
839 	hpetp->hp_ntimer = hdp->hd_nirqs;
840 
841 	for (i = 0; i < hdp->hd_nirqs; i++)
842 		hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
843 
844 	hpet = hpetp->hp_hpet;
845 
846 	cap = readq(&hpet->hpet_cap);
847 
848 	ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
849 
850 	if (hpetp->hp_ntimer != ntimer) {
851 		printk(KERN_WARNING "hpet: number irqs doesn't agree"
852 		       " with number of timers\n");
853 		kfree(hpetp);
854 		return -ENODEV;
855 	}
856 
857 	if (last)
858 		last->hp_next = hpetp;
859 	else
860 		hpets = hpetp;
861 
862 	last = hpetp;
863 
864 	period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
865 		HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
866 	temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
867 	temp += period >> 1; /* round */
868 	do_div(temp, period);
869 	hpetp->hp_tick_freq = temp; /* ticks per second */
870 
871 	printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
872 		hpetp->hp_which, hdp->hd_phys_address,
873 		hpetp->hp_ntimer > 1 ? "s" : "");
874 	for (i = 0; i < hpetp->hp_ntimer; i++)
875 		printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
876 	printk("\n");
877 
878 	printk(KERN_INFO "hpet%u: %u %d-bit timers, %Lu Hz\n",
879 	       hpetp->hp_which, hpetp->hp_ntimer,
880 	       cap & HPET_COUNTER_SIZE_MASK ? 64 : 32, hpetp->hp_tick_freq);
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 	if (!hpet_clocksource) {
913 		hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
914 		CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
915 		clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
916 						clocksource_hpet.shift);
917 		clocksource_register(&clocksource_hpet);
918 		hpetp->hp_clocksource = &clocksource_hpet;
919 		hpet_clocksource = &clocksource_hpet;
920 	}
921 
922 	return 0;
923 }
924 
925 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
926 {
927 	struct hpet_data *hdp;
928 	acpi_status status;
929 	struct acpi_resource_address64 addr;
930 
931 	hdp = data;
932 
933 	status = acpi_resource_to_address64(res, &addr);
934 
935 	if (ACPI_SUCCESS(status)) {
936 		hdp->hd_phys_address = addr.minimum;
937 		hdp->hd_address = ioremap(addr.minimum, addr.address_length);
938 
939 		if (hpet_is_known(hdp)) {
940 			printk(KERN_DEBUG "%s: 0x%lx is busy\n",
941 				__FUNCTION__, hdp->hd_phys_address);
942 			iounmap(hdp->hd_address);
943 			return -EBUSY;
944 		}
945 	} else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
946 		struct acpi_resource_fixed_memory32 *fixmem32;
947 
948 		fixmem32 = &res->data.fixed_memory32;
949 		if (!fixmem32)
950 			return -EINVAL;
951 
952 		hdp->hd_phys_address = fixmem32->address;
953 		hdp->hd_address = ioremap(fixmem32->address,
954 						HPET_RANGE_SIZE);
955 
956 		if (hpet_is_known(hdp)) {
957 			printk(KERN_DEBUG "%s: 0x%lx is busy\n",
958 				__FUNCTION__, hdp->hd_phys_address);
959 			iounmap(hdp->hd_address);
960 			return -EBUSY;
961 		}
962 	} else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
963 		struct acpi_resource_extended_irq *irqp;
964 		int i, irq;
965 
966 		irqp = &res->data.extended_irq;
967 
968 		for (i = 0; i < irqp->interrupt_count; i++) {
969 			irq = acpi_register_gsi(irqp->interrupts[i],
970 				      irqp->triggering, irqp->polarity);
971 			if (irq < 0)
972 				return AE_ERROR;
973 
974 			hdp->hd_irq[hdp->hd_nirqs] = irq;
975 			hdp->hd_nirqs++;
976 		}
977 	}
978 
979 	return AE_OK;
980 }
981 
982 static int hpet_acpi_add(struct acpi_device *device)
983 {
984 	acpi_status result;
985 	struct hpet_data data;
986 
987 	memset(&data, 0, sizeof(data));
988 
989 	result =
990 	    acpi_walk_resources(device->handle, METHOD_NAME__CRS,
991 				hpet_resources, &data);
992 
993 	if (ACPI_FAILURE(result))
994 		return -ENODEV;
995 
996 	if (!data.hd_address || !data.hd_nirqs) {
997 		printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
998 		return -ENODEV;
999 	}
1000 
1001 	return hpet_alloc(&data);
1002 }
1003 
1004 static int hpet_acpi_remove(struct acpi_device *device, int type)
1005 {
1006 	/* XXX need to unregister clocksource, dealloc mem, etc */
1007 	return -EINVAL;
1008 }
1009 
1010 static const struct acpi_device_id hpet_device_ids[] = {
1011 	{"PNP0103", 0},
1012 	{"", 0},
1013 };
1014 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
1015 
1016 static struct acpi_driver hpet_acpi_driver = {
1017 	.name = "hpet",
1018 	.ids = hpet_device_ids,
1019 	.ops = {
1020 		.add = hpet_acpi_add,
1021 		.remove = hpet_acpi_remove,
1022 		},
1023 };
1024 
1025 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1026 
1027 static int __init hpet_init(void)
1028 {
1029 	int result;
1030 
1031 	result = misc_register(&hpet_misc);
1032 	if (result < 0)
1033 		return -ENODEV;
1034 
1035 	sysctl_header = register_sysctl_table(dev_root);
1036 
1037 	result = acpi_bus_register_driver(&hpet_acpi_driver);
1038 	if (result < 0) {
1039 		if (sysctl_header)
1040 			unregister_sysctl_table(sysctl_header);
1041 		misc_deregister(&hpet_misc);
1042 		return result;
1043 	}
1044 
1045 	return 0;
1046 }
1047 
1048 static void __exit hpet_exit(void)
1049 {
1050 	acpi_bus_unregister_driver(&hpet_acpi_driver);
1051 
1052 	if (sysctl_header)
1053 		unregister_sysctl_table(sysctl_header);
1054 	misc_deregister(&hpet_misc);
1055 
1056 	return;
1057 }
1058 
1059 module_init(hpet_init);
1060 module_exit(hpet_exit);
1061 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1062 MODULE_LICENSE("GPL");
1063