rtc: Fix ioctl error path return
[linux-2.6.git] / 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/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 }