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Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target...
[linux-btrfs-devel.git] / drivers / rtc / rtc-dev.c
blobcace6d3aed9a59261bba613af9649b34699fb7a8
1 /*
2 * RTC subsystem, dev interface
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
6 *
7 * based on arch/arm/common/rtctime.c
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/module.h>
15 #include <linux/rtc.h>
16 #include <linux/sched.h>
17 #include "rtc-core.h"
18
19 static dev_t rtc_devt;
20
21 #define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
22
23 static int rtc_dev_open(struct inode *inode, struct file *file)
24 {
25 int err;
26 struct rtc_device *rtc = container_of(inode->i_cdev,
27 struct rtc_device, char_dev);
28 const struct rtc_class_ops *ops = rtc->ops;
29
30 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
31 return -EBUSY;
32
33 file->private_data = rtc;
34
35 err = ops->open ? ops->open(rtc->dev.parent) : 0;
36 if (err == 0) {
37 spin_lock_irq(&rtc->irq_lock);
38 rtc->irq_data = 0;
39 spin_unlock_irq(&rtc->irq_lock);
40
41 return 0;
42 }
43
44 /* something has gone wrong */
45 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
46 return err;
47 }
48
49 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
50 /*
51 * Routine to poll RTC seconds field for change as often as possible,
52 * after first RTC_UIE use timer to reduce polling
53 */
54 static void rtc_uie_task(struct work_struct *work)
55 {
56 struct rtc_device *rtc =
57 container_of(work, struct rtc_device, uie_task);
58 struct rtc_time tm;
59 int num = 0;
60 int err;
61
62 err = rtc_read_time(rtc, &tm);
63
64 spin_lock_irq(&rtc->irq_lock);
65 if (rtc->stop_uie_polling || err) {
66 rtc->uie_task_active = 0;
67 } else if (rtc->oldsecs != tm.tm_sec) {
68 num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
69 rtc->oldsecs = tm.tm_sec;
70 rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
71 rtc->uie_timer_active = 1;
72 rtc->uie_task_active = 0;
73 add_timer(&rtc->uie_timer);
74 } else if (schedule_work(&rtc->uie_task) == 0) {
75 rtc->uie_task_active = 0;
76 }
77 spin_unlock_irq(&rtc->irq_lock);
78 if (num)
79 rtc_handle_legacy_irq(rtc, num, RTC_UF);
80 }
81 static void rtc_uie_timer(unsigned long data)
82 {
83 struct rtc_device *rtc = (struct rtc_device *)data;
84 unsigned long flags;
85
86 spin_lock_irqsave(&rtc->irq_lock, flags);
87 rtc->uie_timer_active = 0;
88 rtc->uie_task_active = 1;
89 if ((schedule_work(&rtc->uie_task) == 0))
90 rtc->uie_task_active = 0;
91 spin_unlock_irqrestore(&rtc->irq_lock, flags);
92 }
93
94 static int clear_uie(struct rtc_device *rtc)
95 {
96 spin_lock_irq(&rtc->irq_lock);
97 if (rtc->uie_irq_active) {
98 rtc->stop_uie_polling = 1;
99 if (rtc->uie_timer_active) {
100 spin_unlock_irq(&rtc->irq_lock);
101 del_timer_sync(&rtc->uie_timer);
102 spin_lock_irq(&rtc->irq_lock);
103 rtc->uie_timer_active = 0;
104 }
105 if (rtc->uie_task_active) {
106 spin_unlock_irq(&rtc->irq_lock);
107 flush_scheduled_work();
108 spin_lock_irq(&rtc->irq_lock);
109 }
110 rtc->uie_irq_active = 0;
111 }
112 spin_unlock_irq(&rtc->irq_lock);
113 return 0;
114 }
115
116 static int set_uie(struct rtc_device *rtc)
117 {
118 struct rtc_time tm;
119 int err;
120
121 err = rtc_read_time(rtc, &tm);
122 if (err)
123 return err;
124 spin_lock_irq(&rtc->irq_lock);
125 if (!rtc->uie_irq_active) {
126 rtc->uie_irq_active = 1;
127 rtc->stop_uie_polling = 0;
128 rtc->oldsecs = tm.tm_sec;
129 rtc->uie_task_active = 1;
130 if (schedule_work(&rtc->uie_task) == 0)
131 rtc->uie_task_active = 0;
132 }
133 rtc->irq_data = 0;
134 spin_unlock_irq(&rtc->irq_lock);
135 return 0;
136 }
137
138 int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled)
139 {
140 if (enabled)
141 return set_uie(rtc);
142 else
143 return clear_uie(rtc);
144 }
145 EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul);
146
147 #endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
148
149 static ssize_t
150 rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
151 {
152 struct rtc_device *rtc = file->private_data;
153
154 DECLARE_WAITQUEUE(wait, current);
155 unsigned long data;
156 ssize_t ret;
157
158 if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
159 return -EINVAL;
160
161 add_wait_queue(&rtc->irq_queue, &wait);
162 do {
163 __set_current_state(TASK_INTERRUPTIBLE);
164
165 spin_lock_irq(&rtc->irq_lock);
166 data = rtc->irq_data;
167 rtc->irq_data = 0;
168 spin_unlock_irq(&rtc->irq_lock);
169
170 if (data != 0) {
171 ret = 0;
172 break;
173 }
174 if (file->f_flags & O_NONBLOCK) {
175 ret = -EAGAIN;
176 break;
177 }
178 if (signal_pending(current)) {
179 ret = -ERESTARTSYS;
180 break;
181 }
182 schedule();
183 } while (1);
184 set_current_state(TASK_RUNNING);
185 remove_wait_queue(&rtc->irq_queue, &wait);
186
187 if (ret == 0) {
188 /* Check for any data updates */
189 if (rtc->ops->read_callback)
190 data = rtc->ops->read_callback(rtc->dev.parent,
191 data);
192
193 if (sizeof(int) != sizeof(long) &&
194 count == sizeof(unsigned int))
195 ret = put_user(data, (unsigned int __user *)buf) ?:
196 sizeof(unsigned int);
197 else
198 ret = put_user(data, (unsigned long __user *)buf) ?:
199 sizeof(unsigned long);
200 }
201 return ret;
202 }
203
204 static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
205 {
206 struct rtc_device *rtc = file->private_data;
207 unsigned long data;
208
209 poll_wait(file, &rtc->irq_queue, wait);
210
211 data = rtc->irq_data;
212
213 return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
214 }
215
216 static long rtc_dev_ioctl(struct file *file,
217 unsigned int cmd, unsigned long arg)
218 {
219 int err = 0;
220 struct rtc_device *rtc = file->private_data;
221 const struct rtc_class_ops *ops = rtc->ops;
222 struct rtc_time tm;
223 struct rtc_wkalrm alarm;
224 void __user *uarg = (void __user *) arg;
225
226 err = mutex_lock_interruptible(&rtc->ops_lock);
227 if (err)
228 return err;
229
230 /* check that the calling task has appropriate permissions
231 * for certain ioctls. doing this check here is useful
232 * to avoid duplicate code in each driver.
233 */
234 switch (cmd) {
235 case RTC_EPOCH_SET:
236 case RTC_SET_TIME:
237 if (!capable(CAP_SYS_TIME))
238 err = -EACCES;
239 break;
240
241 case RTC_IRQP_SET:
242 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
243 err = -EACCES;
244 break;
245
246 case RTC_PIE_ON:
247 if (rtc->irq_freq > rtc->max_user_freq &&
248 !capable(CAP_SYS_RESOURCE))
249 err = -EACCES;
250 break;
251 }
252
253 if (err)
254 goto done;
255
256 /*
257 * Drivers *SHOULD NOT* provide ioctl implementations
258 * for these requests. Instead, provide methods to
259 * support the following code, so that the RTC's main
260 * features are accessible without using ioctls.
261 *
262 * RTC and alarm times will be in UTC, by preference,
263 * but dual-booting with MS-Windows implies RTCs must
264 * use the local wall clock time.
265 */
266
267 switch (cmd) {
268 case RTC_ALM_READ:
269 mutex_unlock(&rtc->ops_lock);
270
271 err = rtc_read_alarm(rtc, &alarm);
272 if (err < 0)
273 return err;
274
275 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
276 err = -EFAULT;
277 return err;
278
279 case RTC_ALM_SET:
280 mutex_unlock(&rtc->ops_lock);
281
282 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
283 return -EFAULT;
284
285 alarm.enabled = 0;
286 alarm.pending = 0;
287 alarm.time.tm_wday = -1;
288 alarm.time.tm_yday = -1;
289 alarm.time.tm_isdst = -1;
290
291 /* RTC_ALM_SET alarms may be up to 24 hours in the future.
292 * Rather than expecting every RTC to implement "don't care"
293 * for day/month/year fields, just force the alarm to have
294 * the right values for those fields.
295 *
296 * RTC_WKALM_SET should be used instead. Not only does it
297 * eliminate the need for a separate RTC_AIE_ON call, it
298 * doesn't have the "alarm 23:59:59 in the future" race.
299 *
300 * NOTE: some legacy code may have used invalid fields as
301 * wildcards, exposing hardware "periodic alarm" capabilities.
302 * Not supported here.
303 */
304 {
305 unsigned long now, then;
306
307 err = rtc_read_time(rtc, &tm);
308 if (err < 0)
309 return err;
310 rtc_tm_to_time(&tm, &now);
311
312 alarm.time.tm_mday = tm.tm_mday;
313 alarm.time.tm_mon = tm.tm_mon;
314 alarm.time.tm_year = tm.tm_year;
315 err = rtc_valid_tm(&alarm.time);
316 if (err < 0)
317 return err;
318 rtc_tm_to_time(&alarm.time, &then);
319
320 /* alarm may need to wrap into tomorrow */
321 if (then < now) {
322 rtc_time_to_tm(now + 24 * 60 * 60, &tm);
323 alarm.time.tm_mday = tm.tm_mday;
324 alarm.time.tm_mon = tm.tm_mon;
325 alarm.time.tm_year = tm.tm_year;
326 }
327 }
328
329 return rtc_set_alarm(rtc, &alarm);
330
331 case RTC_RD_TIME:
332 mutex_unlock(&rtc->ops_lock);
333
334 err = rtc_read_time(rtc, &tm);
335 if (err < 0)
336 return err;
337
338 if (copy_to_user(uarg, &tm, sizeof(tm)))
339 err = -EFAULT;
340 return err;
341
342 case RTC_SET_TIME:
343 mutex_unlock(&rtc->ops_lock);
344
345 if (copy_from_user(&tm, uarg, sizeof(tm)))
346 return -EFAULT;
347
348 return rtc_set_time(rtc, &tm);
349
350 case RTC_PIE_ON:
351 err = rtc_irq_set_state(rtc, NULL, 1);
352 break;
353
354 case RTC_PIE_OFF:
355 err = rtc_irq_set_state(rtc, NULL, 0);
356 break;
357
358 case RTC_AIE_ON:
359 mutex_unlock(&rtc->ops_lock);
360 return rtc_alarm_irq_enable(rtc, 1);
361
362 case RTC_AIE_OFF:
363 mutex_unlock(&rtc->ops_lock);
364 return rtc_alarm_irq_enable(rtc, 0);
365
366 case RTC_UIE_ON:
367 mutex_unlock(&rtc->ops_lock);
368 return rtc_update_irq_enable(rtc, 1);
369
370 case RTC_UIE_OFF:
371 mutex_unlock(&rtc->ops_lock);
372 return rtc_update_irq_enable(rtc, 0);
373
374 case RTC_IRQP_SET:
375 err = rtc_irq_set_freq(rtc, NULL, arg);
376 break;
377
378 case RTC_IRQP_READ:
379 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
380 break;
381
382 #if 0
383 case RTC_EPOCH_SET:
384 #ifndef rtc_epoch
385 /*
386 * There were no RTC clocks before 1900.
387 */
388 if (arg < 1900) {
389 err = -EINVAL;
390 break;
391 }
392 rtc_epoch = arg;
393 err = 0;
394 #endif
395 break;
396
397 case RTC_EPOCH_READ:
398 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
399 break;
400 #endif
401 case RTC_WKALM_SET:
402 mutex_unlock(&rtc->ops_lock);
403 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
404 return -EFAULT;
405
406 return rtc_set_alarm(rtc, &alarm);
407
408 case RTC_WKALM_RD:
409 mutex_unlock(&rtc->ops_lock);
410 err = rtc_read_alarm(rtc, &alarm);
411 if (err < 0)
412 return err;
413
414 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
415 err = -EFAULT;
416 return err;
417
418 default:
419 /* Finally try the driver's ioctl interface */
420 if (ops->ioctl) {
421 err = ops->ioctl(rtc->dev.parent, cmd, arg);
422 if (err == -ENOIOCTLCMD)
423 err = -ENOTTY;
424 } else
425 err = -ENOTTY;
426 break;
427 }
428
429 done:
430 mutex_unlock(&rtc->ops_lock);
431 return err;
432 }
433
434 static int rtc_dev_fasync(int fd, struct file *file, int on)
435 {
436 struct rtc_device *rtc = file->private_data;
437 return fasync_helper(fd, file, on, &rtc->async_queue);
438 }
439
440 static int rtc_dev_release(struct inode *inode, struct file *file)
441 {
442 struct rtc_device *rtc = file->private_data;
443
444 /* We shut down the repeating IRQs that userspace enabled,
445 * since nothing is listening to them.
446 * - Update (UIE) ... currently only managed through ioctls
447 * - Periodic (PIE) ... also used through rtc_*() interface calls
448 *
449 * Leave the alarm alone; it may be set to trigger a system wakeup
450 * later, or be used by kernel code, and is a one-shot event anyway.
451 */
452
453 /* Keep ioctl until all drivers are converted */
454 rtc_dev_ioctl(file, RTC_UIE_OFF, 0);
455 rtc_update_irq_enable(rtc, 0);
456 rtc_irq_set_state(rtc, NULL, 0);
457
458 if (rtc->ops->release)
459 rtc->ops->release(rtc->dev.parent);
460
461 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
462 return 0;
463 }
464
465 static const struct file_operations rtc_dev_fops = {
466 .owner = THIS_MODULE,
467 .llseek = no_llseek,
468 .read = rtc_dev_read,
469 .poll = rtc_dev_poll,
470 .unlocked_ioctl = rtc_dev_ioctl,
471 .open = rtc_dev_open,
472 .release = rtc_dev_release,
473 .fasync = rtc_dev_fasync,
474 };
475
476 /* insertion/removal hooks */
477
478 void rtc_dev_prepare(struct rtc_device *rtc)
479 {
480 if (!rtc_devt)
481 return;
482
483 if (rtc->id >= RTC_DEV_MAX) {
484 pr_debug("%s: too many RTC devices\n", rtc->name);
485 return;
486 }
487
488 rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
489
490 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
491 INIT_WORK(&rtc->uie_task, rtc_uie_task);
492 setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
493 #endif
494
495 cdev_init(&rtc->char_dev, &rtc_dev_fops);
496 rtc->char_dev.owner = rtc->owner;
497 }
498
499 void rtc_dev_add_device(struct rtc_device *rtc)
500 {
501 if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))
502 printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
503 rtc->name, MAJOR(rtc_devt), rtc->id);
504 else
505 pr_debug("%s: dev (%d:%d)\n", rtc->name,
506 MAJOR(rtc_devt), rtc->id);
507 }
508
509 void rtc_dev_del_device(struct rtc_device *rtc)
510 {
511 if (rtc->dev.devt)
512 cdev_del(&rtc->char_dev);
513 }
514
515 void __init rtc_dev_init(void)
516 {
517 int err;
518
519 err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
520 if (err < 0)
521 printk(KERN_ERR "%s: failed to allocate char dev region\n",
522 __FILE__);
523 }
524
525 void __exit rtc_dev_exit(void)
526 {
527 if (rtc_devt)
528 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
529 }
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