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 "rtc-core.h"
17
18 static dev_t rtc_devt;
19
20 #define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
21
rtc_dev_open(struct inode * inode,struct file * file)22 static int rtc_dev_open(struct inode *inode, struct file *file)
23 {
24 int err;
25 struct rtc_device *rtc = container_of(inode->i_cdev,
26 struct rtc_device, char_dev);
27 const struct rtc_class_ops *ops = rtc->ops;
28
29 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
30 return -EBUSY;
31
32 file->private_data = rtc;
33
34 err = ops->open ? ops->open(rtc->dev.parent) : 0;
35 if (err == 0) {
36 spin_lock_irq(&rtc->irq_lock);
37 rtc->irq_data = 0;
38 spin_unlock_irq(&rtc->irq_lock);
39
40 return 0;
41 }
42
43 /* something has gone wrong */
44 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
45 return err;
46 }
47
48 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
49 /*
50 * Routine to poll RTC seconds field for change as often as possible,
51 * after first RTC_UIE use timer to reduce polling
52 */
rtc_uie_task(struct work_struct * work)53 static void rtc_uie_task(struct work_struct *work)
54 {
55 struct rtc_device *rtc =
56 container_of(work, struct rtc_device, uie_task);
57 struct rtc_time tm;
58 int num = 0;
59 int err;
60
61 err = rtc_read_time(rtc, &tm);
62
63 local_irq_disable();
64 spin_lock(&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(&rtc->irq_lock);
78 if (num)
79 rtc_update_irq(rtc, num, RTC_UF | RTC_IRQF);
80 local_irq_enable();
81 }
rtc_uie_timer(unsigned long data)82 static void rtc_uie_timer(unsigned long data)
83 {
84 struct rtc_device *rtc = (struct rtc_device *)data;
85 unsigned long flags;
86
87 spin_lock_irqsave(&rtc->irq_lock, flags);
88 rtc->uie_timer_active = 0;
89 rtc->uie_task_active = 1;
90 if ((schedule_work(&rtc->uie_task) == 0))
91 rtc->uie_task_active = 0;
92 spin_unlock_irqrestore(&rtc->irq_lock, flags);
93 }
94
clear_uie(struct rtc_device * rtc)95 static int clear_uie(struct rtc_device *rtc)
96 {
97 spin_lock_irq(&rtc->irq_lock);
98 if (rtc->uie_irq_active) {
99 rtc->stop_uie_polling = 1;
100 if (rtc->uie_timer_active) {
101 spin_unlock_irq(&rtc->irq_lock);
102 del_timer_sync(&rtc->uie_timer);
103 spin_lock_irq(&rtc->irq_lock);
104 rtc->uie_timer_active = 0;
105 }
106 if (rtc->uie_task_active) {
107 spin_unlock_irq(&rtc->irq_lock);
108 flush_scheduled_work();
109 spin_lock_irq(&rtc->irq_lock);
110 }
111 rtc->uie_irq_active = 0;
112 }
113 spin_unlock_irq(&rtc->irq_lock);
114 return 0;
115 }
116
set_uie(struct rtc_device * rtc)117 static int set_uie(struct rtc_device *rtc)
118 {
119 struct rtc_time tm;
120 int err;
121
122 err = rtc_read_time(rtc, &tm);
123 if (err)
124 return err;
125 spin_lock_irq(&rtc->irq_lock);
126 if (!rtc->uie_irq_active) {
127 rtc->uie_irq_active = 1;
128 rtc->stop_uie_polling = 0;
129 rtc->oldsecs = tm.tm_sec;
130 rtc->uie_task_active = 1;
131 if (schedule_work(&rtc->uie_task) == 0)
132 rtc->uie_task_active = 0;
133 }
134 rtc->irq_data = 0;
135 spin_unlock_irq(&rtc->irq_lock);
136 return 0;
137 }
138
rtc_dev_update_irq_enable_emul(struct rtc_device * rtc,unsigned int enabled)139 int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled)
140 {
141 if (enabled)
142 return set_uie(rtc);
143 else
144 return clear_uie(rtc);
145 }
146 EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul);
147
148 #endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
149
150 static ssize_t
rtc_dev_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)151 rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
152 {
153 struct rtc_device *rtc = file->private_data;
154
155 DECLARE_WAITQUEUE(wait, current);
156 unsigned long data;
157 ssize_t ret;
158
159 if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
160 return -EINVAL;
161
162 add_wait_queue(&rtc->irq_queue, &wait);
163 do {
164 __set_current_state(TASK_INTERRUPTIBLE);
165
166 spin_lock_irq(&rtc->irq_lock);
167 data = rtc->irq_data;
168 rtc->irq_data = 0;
169 spin_unlock_irq(&rtc->irq_lock);
170
171 if (data != 0) {
172 ret = 0;
173 break;
174 }
175 if (file->f_flags & O_NONBLOCK) {
176 ret = -EAGAIN;
177 break;
178 }
179 if (signal_pending(current)) {
180 ret = -ERESTARTSYS;
181 break;
182 }
183 schedule();
184 } while (1);
185 set_current_state(TASK_RUNNING);
186 remove_wait_queue(&rtc->irq_queue, &wait);
187
188 if (ret == 0) {
189 /* Check for any data updates */
190 if (rtc->ops->read_callback)
191 data = rtc->ops->read_callback(rtc->dev.parent,
192 data);
193
194 if (sizeof(int) != sizeof(long) &&
195 count == sizeof(unsigned int))
196 ret = put_user(data, (unsigned int __user *)buf) ?:
197 sizeof(unsigned int);
198 else
199 ret = put_user(data, (unsigned long __user *)buf) ?:
200 sizeof(unsigned long);
201 }
202 return ret;
203 }
204
rtc_dev_poll(struct file * file,poll_table * wait)205 static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
206 {
207 struct rtc_device *rtc = file->private_data;
208 unsigned long data;
209
210 poll_wait(file, &rtc->irq_queue, wait);
211
212 data = rtc->irq_data;
213
214 return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
215 }
216
rtc_dev_ioctl(struct file * file,unsigned int cmd,unsigned long arg)217 static long rtc_dev_ioctl(struct file *file,
218 unsigned int cmd, unsigned long arg)
219 {
220 int err = 0;
221 struct rtc_device *rtc = file->private_data;
222 const struct rtc_class_ops *ops = rtc->ops;
223 struct rtc_time tm;
224 struct rtc_wkalrm alarm;
225 void __user *uarg = (void __user *) arg;
226
227 err = mutex_lock_interruptible(&rtc->ops_lock);
228 if (err)
229 return err;
230
231 /* check that the calling task has appropriate permissions
232 * for certain ioctls. doing this check here is useful
233 * to avoid duplicate code in each driver.
234 */
235 switch (cmd) {
236 case RTC_EPOCH_SET:
237 case RTC_SET_TIME:
238 if (!capable(CAP_SYS_TIME))
239 err = -EACCES;
240 break;
241
242 case RTC_IRQP_SET:
243 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
244 err = -EACCES;
245 break;
246
247 case RTC_PIE_ON:
248 if (rtc->irq_freq > rtc->max_user_freq &&
249 !capable(CAP_SYS_RESOURCE))
250 err = -EACCES;
251 break;
252 }
253
254 if (err)
255 goto done;
256
257 /* try the driver's ioctl interface */
258 if (ops->ioctl) {
259 err = ops->ioctl(rtc->dev.parent, cmd, arg);
260 if (err != -ENOIOCTLCMD) {
261 mutex_unlock(&rtc->ops_lock);
262 return err;
263 }
264 }
265
266 /* if the driver does not provide the ioctl interface
267 * or if that particular ioctl was not implemented
268 * (-ENOIOCTLCMD), we will try to emulate here.
269 *
270 * Drivers *SHOULD NOT* provide ioctl implementations
271 * for these requests. Instead, provide methods to
272 * support the following code, so that the RTC's main
273 * features are accessible without using ioctls.
274 *
275 * RTC and alarm times will be in UTC, by preference,
276 * but dual-booting with MS-Windows implies RTCs must
277 * use the local wall clock time.
278 */
279
280 switch (cmd) {
281 case RTC_ALM_READ:
282 mutex_unlock(&rtc->ops_lock);
283
284 err = rtc_read_alarm(rtc, &alarm);
285 if (err < 0)
286 return err;
287
288 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
289 err = -EFAULT;
290 return err;
291
292 case RTC_ALM_SET:
293 mutex_unlock(&rtc->ops_lock);
294
295 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
296 return -EFAULT;
297
298 alarm.enabled = 0;
299 alarm.pending = 0;
300 alarm.time.tm_wday = -1;
301 alarm.time.tm_yday = -1;
302 alarm.time.tm_isdst = -1;
303
304 /* RTC_ALM_SET alarms may be up to 24 hours in the future.
305 * Rather than expecting every RTC to implement "don't care"
306 * for day/month/year fields, just force the alarm to have
307 * the right values for those fields.
308 *
309 * RTC_WKALM_SET should be used instead. Not only does it
310 * eliminate the need for a separate RTC_AIE_ON call, it
311 * doesn't have the "alarm 23:59:59 in the future" race.
312 *
313 * NOTE: some legacy code may have used invalid fields as
314 * wildcards, exposing hardware "periodic alarm" capabilities.
315 * Not supported here.
316 */
317 {
318 unsigned long now, then;
319
320 err = rtc_read_time(rtc, &tm);
321 if (err < 0)
322 return err;
323 rtc_tm_to_time(&tm, &now);
324
325 alarm.time.tm_mday = tm.tm_mday;
326 alarm.time.tm_mon = tm.tm_mon;
327 alarm.time.tm_year = tm.tm_year;
328 err = rtc_valid_tm(&alarm.time);
329 if (err < 0)
330 return err;
331 rtc_tm_to_time(&alarm.time, &then);
332
333 /* alarm may need to wrap into tomorrow */
334 if (then < now) {
335 rtc_time_to_tm(now + 24 * 60 * 60, &tm);
336 alarm.time.tm_mday = tm.tm_mday;
337 alarm.time.tm_mon = tm.tm_mon;
338 alarm.time.tm_year = tm.tm_year;
339 }
340 }
341
342 return rtc_set_alarm(rtc, &alarm);
343
344 case RTC_RD_TIME:
345 mutex_unlock(&rtc->ops_lock);
346
347 err = rtc_read_time(rtc, &tm);
348 if (err < 0)
349 return err;
350
351 if (copy_to_user(uarg, &tm, sizeof(tm)))
352 err = -EFAULT;
353 return err;
354
355 case RTC_SET_TIME:
356 mutex_unlock(&rtc->ops_lock);
357
358 if (copy_from_user(&tm, uarg, sizeof(tm)))
359 return -EFAULT;
360
361 return rtc_set_time(rtc, &tm);
362
363 case RTC_PIE_ON:
364 err = rtc_irq_set_state(rtc, NULL, 1);
365 break;
366
367 case RTC_PIE_OFF:
368 err = rtc_irq_set_state(rtc, NULL, 0);
369 break;
370
371 case RTC_AIE_ON:
372 mutex_unlock(&rtc->ops_lock);
373 return rtc_alarm_irq_enable(rtc, 1);
374
375 case RTC_AIE_OFF:
376 mutex_unlock(&rtc->ops_lock);
377 return rtc_alarm_irq_enable(rtc, 0);
378
379 case RTC_UIE_ON:
380 mutex_unlock(&rtc->ops_lock);
381 return rtc_update_irq_enable(rtc, 1);
382
383 case RTC_UIE_OFF:
384 mutex_unlock(&rtc->ops_lock);
385 return rtc_update_irq_enable(rtc, 0);
386
387 case RTC_IRQP_SET:
388 err = rtc_irq_set_freq(rtc, NULL, arg);
389 break;
390
391 case RTC_IRQP_READ:
392 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
393 break;
394
395 #if 0
396 case RTC_EPOCH_SET:
397 #ifndef rtc_epoch
398 /*
399 * There were no RTC clocks before 1900.
400 */
401 if (arg < 1900) {
402 err = -EINVAL;
403 break;
404 }
405 rtc_epoch = arg;
406 err = 0;
407 #endif
408 break;
409
410 case RTC_EPOCH_READ:
411 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
412 break;
413 #endif
414 case RTC_WKALM_SET:
415 mutex_unlock(&rtc->ops_lock);
416 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
417 return -EFAULT;
418
419 return rtc_set_alarm(rtc, &alarm);
420
421 case RTC_WKALM_RD:
422 mutex_unlock(&rtc->ops_lock);
423 err = rtc_read_alarm(rtc, &alarm);
424 if (err < 0)
425 return err;
426
427 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
428 err = -EFAULT;
429 return err;
430
431 default:
432 err = -ENOTTY;
433 break;
434 }
435
436 done:
437 mutex_unlock(&rtc->ops_lock);
438 return err;
439 }
440
rtc_dev_fasync(int fd,struct file * file,int on)441 static int rtc_dev_fasync(int fd, struct file *file, int on)
442 {
443 struct rtc_device *rtc = file->private_data;
444 return fasync_helper(fd, file, on, &rtc->async_queue);
445 }
446
rtc_dev_release(struct inode * inode,struct file * file)447 static int rtc_dev_release(struct inode *inode, struct file *file)
448 {
449 struct rtc_device *rtc = file->private_data;
450
451 /* We shut down the repeating IRQs that userspace enabled,
452 * since nothing is listening to them.
453 * - Update (UIE) ... currently only managed through ioctls
454 * - Periodic (PIE) ... also used through rtc_*() interface calls
455 *
456 * Leave the alarm alone; it may be set to trigger a system wakeup
457 * later, or be used by kernel code, and is a one-shot event anyway.
458 */
459
460 /* Keep ioctl until all drivers are converted */
461 rtc_dev_ioctl(file, RTC_UIE_OFF, 0);
462 rtc_update_irq_enable(rtc, 0);
463 rtc_irq_set_state(rtc, NULL, 0);
464
465 if (rtc->ops->release)
466 rtc->ops->release(rtc->dev.parent);
467
468 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
469 return 0;
470 }
471
472 static const struct file_operations rtc_dev_fops = {
473 .owner = THIS_MODULE,
474 .llseek = no_llseek,
475 .read = rtc_dev_read,
476 .poll = rtc_dev_poll,
477 .unlocked_ioctl = rtc_dev_ioctl,
478 .open = rtc_dev_open,
479 .release = rtc_dev_release,
480 .fasync = rtc_dev_fasync,
481 };
482
483 /* insertion/removal hooks */
484
rtc_dev_prepare(struct rtc_device * rtc)485 void rtc_dev_prepare(struct rtc_device *rtc)
486 {
487 if (!rtc_devt)
488 return;
489
490 if (rtc->id >= RTC_DEV_MAX) {
491 pr_debug("%s: too many RTC devices\n", rtc->name);
492 return;
493 }
494
495 rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
496
497 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
498 INIT_WORK(&rtc->uie_task, rtc_uie_task);
499 setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
500 #endif
501
502 cdev_init(&rtc->char_dev, &rtc_dev_fops);
503 rtc->char_dev.owner = rtc->owner;
504 }
505
rtc_dev_add_device(struct rtc_device * rtc)506 void rtc_dev_add_device(struct rtc_device *rtc)
507 {
508 if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))
509 printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
510 rtc->name, MAJOR(rtc_devt), rtc->id);
511 else
512 pr_debug("%s: dev (%d:%d)\n", rtc->name,
513 MAJOR(rtc_devt), rtc->id);
514 }
515
rtc_dev_del_device(struct rtc_device * rtc)516 void rtc_dev_del_device(struct rtc_device *rtc)
517 {
518 if (rtc->dev.devt)
519 cdev_del(&rtc->char_dev);
520 }
521
rtc_dev_init(void)522 void __init rtc_dev_init(void)
523 {
524 int err;
525
526 err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
527 if (err < 0)
528 printk(KERN_ERR "%s: failed to allocate char dev region\n",
529 __FILE__);
530 }
531
rtc_dev_exit(void)532 void __exit rtc_dev_exit(void)
533 {
534 if (rtc_devt)
535 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
536 }
537