]> err.no Git - linux-2.6/blob - drivers/rtc/rtc-dev.c
Merge branch 'sbp2-spindown' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee139...
[linux-2.6] / drivers / rtc / rtc-dev.c
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/smp_lock.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         lock_kernel();
31         if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) {
32                 err = -EBUSY;
33                 goto out;
34         }
35
36         file->private_data = rtc;
37
38         err = ops->open ? ops->open(rtc->dev.parent) : 0;
39         if (err == 0) {
40                 spin_lock_irq(&rtc->irq_lock);
41                 rtc->irq_data = 0;
42                 spin_unlock_irq(&rtc->irq_lock);
43
44                 goto out;
45         }
46
47         /* something has gone wrong */
48         clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
49 out:
50         unlock_kernel();
51         return err;
52 }
53
54 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
55 /*
56  * Routine to poll RTC seconds field for change as often as possible,
57  * after first RTC_UIE use timer to reduce polling
58  */
59 static void rtc_uie_task(struct work_struct *work)
60 {
61         struct rtc_device *rtc =
62                 container_of(work, struct rtc_device, uie_task);
63         struct rtc_time tm;
64         int num = 0;
65         int err;
66
67         err = rtc_read_time(rtc, &tm);
68
69         local_irq_disable();
70         spin_lock(&rtc->irq_lock);
71         if (rtc->stop_uie_polling || err) {
72                 rtc->uie_task_active = 0;
73         } else if (rtc->oldsecs != tm.tm_sec) {
74                 num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
75                 rtc->oldsecs = tm.tm_sec;
76                 rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
77                 rtc->uie_timer_active = 1;
78                 rtc->uie_task_active = 0;
79                 add_timer(&rtc->uie_timer);
80         } else if (schedule_work(&rtc->uie_task) == 0) {
81                 rtc->uie_task_active = 0;
82         }
83         spin_unlock(&rtc->irq_lock);
84         if (num)
85                 rtc_update_irq(rtc, num, RTC_UF | RTC_IRQF);
86         local_irq_enable();
87 }
88 static void rtc_uie_timer(unsigned long data)
89 {
90         struct rtc_device *rtc = (struct rtc_device *)data;
91         unsigned long flags;
92
93         spin_lock_irqsave(&rtc->irq_lock, flags);
94         rtc->uie_timer_active = 0;
95         rtc->uie_task_active = 1;
96         if ((schedule_work(&rtc->uie_task) == 0))
97                 rtc->uie_task_active = 0;
98         spin_unlock_irqrestore(&rtc->irq_lock, flags);
99 }
100
101 static void clear_uie(struct rtc_device *rtc)
102 {
103         spin_lock_irq(&rtc->irq_lock);
104         if (rtc->irq_active) {
105                 rtc->stop_uie_polling = 1;
106                 if (rtc->uie_timer_active) {
107                         spin_unlock_irq(&rtc->irq_lock);
108                         del_timer_sync(&rtc->uie_timer);
109                         spin_lock_irq(&rtc->irq_lock);
110                         rtc->uie_timer_active = 0;
111                 }
112                 if (rtc->uie_task_active) {
113                         spin_unlock_irq(&rtc->irq_lock);
114                         flush_scheduled_work();
115                         spin_lock_irq(&rtc->irq_lock);
116                 }
117                 rtc->irq_active = 0;
118         }
119         spin_unlock_irq(&rtc->irq_lock);
120 }
121
122 static int set_uie(struct rtc_device *rtc)
123 {
124         struct rtc_time tm;
125         int err;
126
127         err = rtc_read_time(rtc, &tm);
128         if (err)
129                 return err;
130         spin_lock_irq(&rtc->irq_lock);
131         if (!rtc->irq_active) {
132                 rtc->irq_active = 1;
133                 rtc->stop_uie_polling = 0;
134                 rtc->oldsecs = tm.tm_sec;
135                 rtc->uie_task_active = 1;
136                 if (schedule_work(&rtc->uie_task) == 0)
137                         rtc->uie_task_active = 0;
138         }
139         rtc->irq_data = 0;
140         spin_unlock_irq(&rtc->irq_lock);
141         return 0;
142 }
143 #endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
144
145 static ssize_t
146 rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
147 {
148         struct rtc_device *rtc = file->private_data;
149
150         DECLARE_WAITQUEUE(wait, current);
151         unsigned long data;
152         ssize_t ret;
153
154         if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
155                 return -EINVAL;
156
157         add_wait_queue(&rtc->irq_queue, &wait);
158         do {
159                 __set_current_state(TASK_INTERRUPTIBLE);
160
161                 spin_lock_irq(&rtc->irq_lock);
162                 data = rtc->irq_data;
163                 rtc->irq_data = 0;
164                 spin_unlock_irq(&rtc->irq_lock);
165
166                 if (data != 0) {
167                         ret = 0;
168                         break;
169                 }
170                 if (file->f_flags & O_NONBLOCK) {
171                         ret = -EAGAIN;
172                         break;
173                 }
174                 if (signal_pending(current)) {
175                         ret = -ERESTARTSYS;
176                         break;
177                 }
178                 schedule();
179         } while (1);
180         set_current_state(TASK_RUNNING);
181         remove_wait_queue(&rtc->irq_queue, &wait);
182
183         if (ret == 0) {
184                 /* Check for any data updates */
185                 if (rtc->ops->read_callback)
186                         data = rtc->ops->read_callback(rtc->dev.parent,
187                                                        data);
188
189                 if (sizeof(int) != sizeof(long) &&
190                     count == sizeof(unsigned int))
191                         ret = put_user(data, (unsigned int __user *)buf) ?:
192                                 sizeof(unsigned int);
193                 else
194                         ret = put_user(data, (unsigned long __user *)buf) ?:
195                                 sizeof(unsigned long);
196         }
197         return ret;
198 }
199
200 static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
201 {
202         struct rtc_device *rtc = file->private_data;
203         unsigned long data;
204
205         poll_wait(file, &rtc->irq_queue, wait);
206
207         data = rtc->irq_data;
208
209         return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
210 }
211
212 static int rtc_dev_ioctl(struct inode *inode, struct file *file,
213                 unsigned int cmd, unsigned long arg)
214 {
215         int err = 0;
216         struct rtc_device *rtc = file->private_data;
217         const struct rtc_class_ops *ops = rtc->ops;
218         struct rtc_time tm;
219         struct rtc_wkalrm alarm;
220         void __user *uarg = (void __user *) arg;
221
222         /* check that the calling task has appropriate permissions
223          * for certain ioctls. doing this check here is useful
224          * to avoid duplicate code in each driver.
225          */
226         switch (cmd) {
227         case RTC_EPOCH_SET:
228         case RTC_SET_TIME:
229                 if (!capable(CAP_SYS_TIME))
230                         return -EACCES;
231                 break;
232
233         case RTC_IRQP_SET:
234                 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
235                         return -EACCES;
236                 break;
237
238         case RTC_PIE_ON:
239                 if (rtc->irq_freq > rtc->max_user_freq &&
240                                 !capable(CAP_SYS_RESOURCE))
241                         return -EACCES;
242                 break;
243         }
244
245         /* try the driver's ioctl interface */
246         if (ops->ioctl) {
247                 err = ops->ioctl(rtc->dev.parent, cmd, arg);
248                 if (err != -ENOIOCTLCMD)
249                         return err;
250         }
251
252         /* if the driver does not provide the ioctl interface
253          * or if that particular ioctl was not implemented
254          * (-ENOIOCTLCMD), we will try to emulate here.
255          *
256          * Drivers *SHOULD NOT* provide ioctl implementations
257          * for these requests.  Instead, provide methods to
258          * support the following code, so that the RTC's main
259          * features are accessible without using ioctls.
260          *
261          * RTC and alarm times will be in UTC, by preference,
262          * but dual-booting with MS-Windows implies RTCs must
263          * use the local wall clock time.
264          */
265
266         switch (cmd) {
267         case RTC_ALM_READ:
268                 err = rtc_read_alarm(rtc, &alarm);
269                 if (err < 0)
270                         return err;
271
272                 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
273                         return -EFAULT;
274                 break;
275
276         case RTC_ALM_SET:
277                 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
278                         return -EFAULT;
279
280                 alarm.enabled = 0;
281                 alarm.pending = 0;
282                 alarm.time.tm_wday = -1;
283                 alarm.time.tm_yday = -1;
284                 alarm.time.tm_isdst = -1;
285
286                 /* RTC_ALM_SET alarms may be up to 24 hours in the future.
287                  * Rather than expecting every RTC to implement "don't care"
288                  * for day/month/year fields, just force the alarm to have
289                  * the right values for those fields.
290                  *
291                  * RTC_WKALM_SET should be used instead.  Not only does it
292                  * eliminate the need for a separate RTC_AIE_ON call, it
293                  * doesn't have the "alarm 23:59:59 in the future" race.
294                  *
295                  * NOTE:  some legacy code may have used invalid fields as
296                  * wildcards, exposing hardware "periodic alarm" capabilities.
297                  * Not supported here.
298                  */
299                 {
300                         unsigned long now, then;
301
302                         err = rtc_read_time(rtc, &tm);
303                         if (err < 0)
304                                 return err;
305                         rtc_tm_to_time(&tm, &now);
306
307                         alarm.time.tm_mday = tm.tm_mday;
308                         alarm.time.tm_mon = tm.tm_mon;
309                         alarm.time.tm_year = tm.tm_year;
310                         err  = rtc_valid_tm(&alarm.time);
311                         if (err < 0)
312                                 return err;
313                         rtc_tm_to_time(&alarm.time, &then);
314
315                         /* alarm may need to wrap into tomorrow */
316                         if (then < now) {
317                                 rtc_time_to_tm(now + 24 * 60 * 60, &tm);
318                                 alarm.time.tm_mday = tm.tm_mday;
319                                 alarm.time.tm_mon = tm.tm_mon;
320                                 alarm.time.tm_year = tm.tm_year;
321                         }
322                 }
323
324                 err = rtc_set_alarm(rtc, &alarm);
325                 break;
326
327         case RTC_RD_TIME:
328                 err = rtc_read_time(rtc, &tm);
329                 if (err < 0)
330                         return err;
331
332                 if (copy_to_user(uarg, &tm, sizeof(tm)))
333                         return -EFAULT;
334                 break;
335
336         case RTC_SET_TIME:
337                 if (copy_from_user(&tm, uarg, sizeof(tm)))
338                         return -EFAULT;
339
340                 err = rtc_set_time(rtc, &tm);
341                 break;
342
343         case RTC_PIE_ON:
344                 err = rtc_irq_set_state(rtc, NULL, 1);
345                 break;
346
347         case RTC_PIE_OFF:
348                 err = rtc_irq_set_state(rtc, NULL, 0);
349                 break;
350
351         case RTC_IRQP_SET:
352                 err = rtc_irq_set_freq(rtc, NULL, arg);
353                 break;
354
355         case RTC_IRQP_READ:
356                 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
357                 break;
358
359 #if 0
360         case RTC_EPOCH_SET:
361 #ifndef rtc_epoch
362                 /*
363                  * There were no RTC clocks before 1900.
364                  */
365                 if (arg < 1900) {
366                         err = -EINVAL;
367                         break;
368                 }
369                 rtc_epoch = arg;
370                 err = 0;
371 #endif
372                 break;
373
374         case RTC_EPOCH_READ:
375                 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
376                 break;
377 #endif
378         case RTC_WKALM_SET:
379                 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
380                         return -EFAULT;
381
382                 err = rtc_set_alarm(rtc, &alarm);
383                 break;
384
385         case RTC_WKALM_RD:
386                 err = rtc_read_alarm(rtc, &alarm);
387                 if (err < 0)
388                         return err;
389
390                 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
391                         return -EFAULT;
392                 break;
393
394 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
395         case RTC_UIE_OFF:
396                 clear_uie(rtc);
397                 return 0;
398
399         case RTC_UIE_ON:
400                 return set_uie(rtc);
401 #endif
402         default:
403                 err = -ENOTTY;
404                 break;
405         }
406
407         return err;
408 }
409
410 static int rtc_dev_release(struct inode *inode, struct file *file)
411 {
412         struct rtc_device *rtc = file->private_data;
413
414 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
415         clear_uie(rtc);
416 #endif
417         if (rtc->ops->release)
418                 rtc->ops->release(rtc->dev.parent);
419
420         clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
421         return 0;
422 }
423
424 static int rtc_dev_fasync(int fd, struct file *file, int on)
425 {
426         struct rtc_device *rtc = file->private_data;
427         return fasync_helper(fd, file, on, &rtc->async_queue);
428 }
429
430 static const struct file_operations rtc_dev_fops = {
431         .owner          = THIS_MODULE,
432         .llseek         = no_llseek,
433         .read           = rtc_dev_read,
434         .poll           = rtc_dev_poll,
435         .ioctl          = rtc_dev_ioctl,
436         .open           = rtc_dev_open,
437         .release        = rtc_dev_release,
438         .fasync         = rtc_dev_fasync,
439 };
440
441 /* insertion/removal hooks */
442
443 void rtc_dev_prepare(struct rtc_device *rtc)
444 {
445         if (!rtc_devt)
446                 return;
447
448         if (rtc->id >= RTC_DEV_MAX) {
449                 pr_debug("%s: too many RTC devices\n", rtc->name);
450                 return;
451         }
452
453         rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
454
455 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
456         INIT_WORK(&rtc->uie_task, rtc_uie_task);
457         setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
458 #endif
459
460         cdev_init(&rtc->char_dev, &rtc_dev_fops);
461         rtc->char_dev.owner = rtc->owner;
462 }
463
464 void rtc_dev_add_device(struct rtc_device *rtc)
465 {
466         if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))
467                 printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
468                         rtc->name, MAJOR(rtc_devt), rtc->id);
469         else
470                 pr_debug("%s: dev (%d:%d)\n", rtc->name,
471                         MAJOR(rtc_devt), rtc->id);
472 }
473
474 void rtc_dev_del_device(struct rtc_device *rtc)
475 {
476         if (rtc->dev.devt)
477                 cdev_del(&rtc->char_dev);
478 }
479
480 void __init rtc_dev_init(void)
481 {
482         int err;
483
484         err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
485         if (err < 0)
486                 printk(KERN_ERR "%s: failed to allocate char dev region\n",
487                         __FILE__);
488 }
489
490 void __exit rtc_dev_exit(void)
491 {
492         if (rtc_devt)
493                 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
494 }