Merge branch 'for-2.6.27' of git://git.marvell.com/mv643xx_eth into upstream-fixes
[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 long rtc_dev_ioctl(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         err = mutex_lock_interruptible(&rtc->ops_lock);
223         if (err)
224                 return -EBUSY;
225
226         /* check that the calling task has appropriate permissions
227          * for certain ioctls. doing this check here is useful
228          * to avoid duplicate code in each driver.
229          */
230         switch (cmd) {
231         case RTC_EPOCH_SET:
232         case RTC_SET_TIME:
233                 if (!capable(CAP_SYS_TIME))
234                         err = -EACCES;
235                 break;
236
237         case RTC_IRQP_SET:
238                 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
239                         err = -EACCES;
240                 break;
241
242         case RTC_PIE_ON:
243                 if (rtc->irq_freq > rtc->max_user_freq &&
244                                 !capable(CAP_SYS_RESOURCE))
245                         err = -EACCES;
246                 break;
247         }
248
249         if (err)
250                 goto done;
251
252         /* try the driver's ioctl interface */
253         if (ops->ioctl) {
254                 err = ops->ioctl(rtc->dev.parent, cmd, arg);
255                 if (err != -ENOIOCTLCMD) {
256                         mutex_unlock(&rtc->ops_lock);
257                         return err;
258                 }
259         }
260
261         /* if the driver does not provide the ioctl interface
262          * or if that particular ioctl was not implemented
263          * (-ENOIOCTLCMD), we will try to emulate here.
264          *
265          * Drivers *SHOULD NOT* provide ioctl implementations
266          * for these requests.  Instead, provide methods to
267          * support the following code, so that the RTC's main
268          * features are accessible without using ioctls.
269          *
270          * RTC and alarm times will be in UTC, by preference,
271          * but dual-booting with MS-Windows implies RTCs must
272          * use the local wall clock time.
273          */
274
275         switch (cmd) {
276         case RTC_ALM_READ:
277                 mutex_unlock(&rtc->ops_lock);
278
279                 err = rtc_read_alarm(rtc, &alarm);
280                 if (err < 0)
281                         return err;
282
283                 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
284                         err = -EFAULT;
285                 return err;
286
287         case RTC_ALM_SET:
288                 mutex_unlock(&rtc->ops_lock);
289
290                 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
291                         return -EFAULT;
292
293                 alarm.enabled = 0;
294                 alarm.pending = 0;
295                 alarm.time.tm_wday = -1;
296                 alarm.time.tm_yday = -1;
297                 alarm.time.tm_isdst = -1;
298
299                 /* RTC_ALM_SET alarms may be up to 24 hours in the future.
300                  * Rather than expecting every RTC to implement "don't care"
301                  * for day/month/year fields, just force the alarm to have
302                  * the right values for those fields.
303                  *
304                  * RTC_WKALM_SET should be used instead.  Not only does it
305                  * eliminate the need for a separate RTC_AIE_ON call, it
306                  * doesn't have the "alarm 23:59:59 in the future" race.
307                  *
308                  * NOTE:  some legacy code may have used invalid fields as
309                  * wildcards, exposing hardware "periodic alarm" capabilities.
310                  * Not supported here.
311                  */
312                 {
313                         unsigned long now, then;
314
315                         err = rtc_read_time(rtc, &tm);
316                         if (err < 0)
317                                 return err;
318                         rtc_tm_to_time(&tm, &now);
319
320                         alarm.time.tm_mday = tm.tm_mday;
321                         alarm.time.tm_mon = tm.tm_mon;
322                         alarm.time.tm_year = tm.tm_year;
323                         err  = rtc_valid_tm(&alarm.time);
324                         if (err < 0)
325                                 return err;
326                         rtc_tm_to_time(&alarm.time, &then);
327
328                         /* alarm may need to wrap into tomorrow */
329                         if (then < now) {
330                                 rtc_time_to_tm(now + 24 * 60 * 60, &tm);
331                                 alarm.time.tm_mday = tm.tm_mday;
332                                 alarm.time.tm_mon = tm.tm_mon;
333                                 alarm.time.tm_year = tm.tm_year;
334                         }
335                 }
336
337                 return rtc_set_alarm(rtc, &alarm);
338
339         case RTC_RD_TIME:
340                 mutex_unlock(&rtc->ops_lock);
341
342                 err = rtc_read_time(rtc, &tm);
343                 if (err < 0)
344                         return err;
345
346                 if (copy_to_user(uarg, &tm, sizeof(tm)))
347                         err = -EFAULT;
348                 return err;
349
350         case RTC_SET_TIME:
351                 mutex_unlock(&rtc->ops_lock);
352
353                 if (copy_from_user(&tm, uarg, sizeof(tm)))
354                         return -EFAULT;
355
356                 return rtc_set_time(rtc, &tm);
357
358         case RTC_PIE_ON:
359                 err = rtc_irq_set_state(rtc, NULL, 1);
360                 break;
361
362         case RTC_PIE_OFF:
363                 err = rtc_irq_set_state(rtc, NULL, 0);
364                 break;
365
366         case RTC_IRQP_SET:
367                 err = rtc_irq_set_freq(rtc, NULL, arg);
368                 break;
369
370         case RTC_IRQP_READ:
371                 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
372                 break;
373
374 #if 0
375         case RTC_EPOCH_SET:
376 #ifndef rtc_epoch
377                 /*
378                  * There were no RTC clocks before 1900.
379                  */
380                 if (arg < 1900) {
381                         err = -EINVAL;
382                         break;
383                 }
384                 rtc_epoch = arg;
385                 err = 0;
386 #endif
387                 break;
388
389         case RTC_EPOCH_READ:
390                 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
391                 break;
392 #endif
393         case RTC_WKALM_SET:
394                 mutex_unlock(&rtc->ops_lock);
395                 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
396                         return -EFAULT;
397
398                 return rtc_set_alarm(rtc, &alarm);
399
400         case RTC_WKALM_RD:
401                 mutex_unlock(&rtc->ops_lock);
402                 err = rtc_read_alarm(rtc, &alarm);
403                 if (err < 0)
404                         return err;
405
406                 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
407                         err = -EFAULT;
408                 return err;
409
410 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
411         case RTC_UIE_OFF:
412                 clear_uie(rtc);
413                 break;
414
415         case RTC_UIE_ON:
416                 err = set_uie(rtc);
417 #endif
418         default:
419                 err = -ENOTTY;
420                 break;
421         }
422
423 done:
424         mutex_unlock(&rtc->ops_lock);
425         return err;
426 }
427
428 static int rtc_dev_release(struct inode *inode, struct file *file)
429 {
430         struct rtc_device *rtc = file->private_data;
431
432 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
433         clear_uie(rtc);
434 #endif
435         if (rtc->ops->release)
436                 rtc->ops->release(rtc->dev.parent);
437
438         clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
439         return 0;
440 }
441
442 static int rtc_dev_fasync(int fd, struct file *file, int on)
443 {
444         struct rtc_device *rtc = file->private_data;
445         return fasync_helper(fd, file, on, &rtc->async_queue);
446 }
447
448 static const struct file_operations rtc_dev_fops = {
449         .owner          = THIS_MODULE,
450         .llseek         = no_llseek,
451         .read           = rtc_dev_read,
452         .poll           = rtc_dev_poll,
453         .unlocked_ioctl = rtc_dev_ioctl,
454         .open           = rtc_dev_open,
455         .release        = rtc_dev_release,
456         .fasync         = rtc_dev_fasync,
457 };
458
459 /* insertion/removal hooks */
460
461 void rtc_dev_prepare(struct rtc_device *rtc)
462 {
463         if (!rtc_devt)
464                 return;
465
466         if (rtc->id >= RTC_DEV_MAX) {
467                 pr_debug("%s: too many RTC devices\n", rtc->name);
468                 return;
469         }
470
471         rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
472
473 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
474         INIT_WORK(&rtc->uie_task, rtc_uie_task);
475         setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
476 #endif
477
478         cdev_init(&rtc->char_dev, &rtc_dev_fops);
479         rtc->char_dev.owner = rtc->owner;
480 }
481
482 void rtc_dev_add_device(struct rtc_device *rtc)
483 {
484         if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))
485                 printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
486                         rtc->name, MAJOR(rtc_devt), rtc->id);
487         else
488                 pr_debug("%s: dev (%d:%d)\n", rtc->name,
489                         MAJOR(rtc_devt), rtc->id);
490 }
491
492 void rtc_dev_del_device(struct rtc_device *rtc)
493 {
494         if (rtc->dev.devt)
495                 cdev_del(&rtc->char_dev);
496 }
497
498 void __init rtc_dev_init(void)
499 {
500         int err;
501
502         err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
503         if (err < 0)
504                 printk(KERN_ERR "%s: failed to allocate char dev region\n",
505                         __FILE__);
506 }
507
508 void __exit rtc_dev_exit(void)
509 {
510         if (rtc_devt)
511                 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
512 }