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