rtc: rtc-s35390a.c needs the bitreverse library
[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 "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
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  */
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 }
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
95 static void clear_uie(struct rtc_device *rtc)
96 {
97         spin_lock_irq(&rtc->irq_lock);
98         if (rtc->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->irq_active = 0;
112         }
113         spin_unlock_irq(&rtc->irq_lock);
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->irq_active) {
126                 rtc->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 #endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
138
139 static ssize_t
140 rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
141 {
142         struct rtc_device *rtc = file->private_data;
143
144         DECLARE_WAITQUEUE(wait, current);
145         unsigned long data;
146         ssize_t ret;
147
148         if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
149                 return -EINVAL;
150
151         add_wait_queue(&rtc->irq_queue, &wait);
152         do {
153                 __set_current_state(TASK_INTERRUPTIBLE);
154
155                 spin_lock_irq(&rtc->irq_lock);
156                 data = rtc->irq_data;
157                 rtc->irq_data = 0;
158                 spin_unlock_irq(&rtc->irq_lock);
159
160                 if (data != 0) {
161                         ret = 0;
162                         break;
163                 }
164                 if (file->f_flags & O_NONBLOCK) {
165                         ret = -EAGAIN;
166                         break;
167                 }
168                 if (signal_pending(current)) {
169                         ret = -ERESTARTSYS;
170                         break;
171                 }
172                 schedule();
173         } while (1);
174         set_current_state(TASK_RUNNING);
175         remove_wait_queue(&rtc->irq_queue, &wait);
176
177         if (ret == 0) {
178                 /* Check for any data updates */
179                 if (rtc->ops->read_callback)
180                         data = rtc->ops->read_callback(rtc->dev.parent,
181                                                        data);
182
183                 if (sizeof(int) != sizeof(long) &&
184                     count == sizeof(unsigned int))
185                         ret = put_user(data, (unsigned int __user *)buf) ?:
186                                 sizeof(unsigned int);
187                 else
188                         ret = put_user(data, (unsigned long __user *)buf) ?:
189                                 sizeof(unsigned long);
190         }
191         return ret;
192 }
193
194 static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
195 {
196         struct rtc_device *rtc = file->private_data;
197         unsigned long data;
198
199         poll_wait(file, &rtc->irq_queue, wait);
200
201         data = rtc->irq_data;
202
203         return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
204 }
205
206 static int rtc_dev_ioctl(struct inode *inode, struct file *file,
207                 unsigned int cmd, unsigned long arg)
208 {
209         int err = 0;
210         struct rtc_device *rtc = file->private_data;
211         const struct rtc_class_ops *ops = rtc->ops;
212         struct rtc_time tm;
213         struct rtc_wkalrm alarm;
214         void __user *uarg = (void __user *) arg;
215
216         /* check that the calling task has appropriate permissions
217          * for certain ioctls. doing this check here is useful
218          * to avoid duplicate code in each driver.
219          */
220         switch (cmd) {
221         case RTC_EPOCH_SET:
222         case RTC_SET_TIME:
223                 if (!capable(CAP_SYS_TIME))
224                         return -EACCES;
225                 break;
226
227         case RTC_IRQP_SET:
228                 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
229                         return -EACCES;
230                 break;
231
232         case RTC_PIE_ON:
233                 if (rtc->irq_freq > rtc->max_user_freq &&
234                                 !capable(CAP_SYS_RESOURCE))
235                         return -EACCES;
236                 break;
237         }
238
239         /* try the driver's ioctl interface */
240         if (ops->ioctl) {
241                 err = ops->ioctl(rtc->dev.parent, cmd, arg);
242                 if (err != -ENOIOCTLCMD)
243                         return err;
244         }
245
246         /* if the driver does not provide the ioctl interface
247          * or if that particular ioctl was not implemented
248          * (-ENOIOCTLCMD), we will try to emulate here.
249          *
250          * Drivers *SHOULD NOT* provide ioctl implementations
251          * for these requests.  Instead, provide methods to
252          * support the following code, so that the RTC's main
253          * features are accessible without using ioctls.
254          *
255          * RTC and alarm times will be in UTC, by preference,
256          * but dual-booting with MS-Windows implies RTCs must
257          * use the local wall clock time.
258          */
259
260         switch (cmd) {
261         case RTC_ALM_READ:
262                 err = rtc_read_alarm(rtc, &alarm);
263                 if (err < 0)
264                         return err;
265
266                 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
267                         return -EFAULT;
268                 break;
269
270         case RTC_ALM_SET:
271                 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
272                         return -EFAULT;
273
274                 alarm.enabled = 0;
275                 alarm.pending = 0;
276                 alarm.time.tm_wday = -1;
277                 alarm.time.tm_yday = -1;
278                 alarm.time.tm_isdst = -1;
279
280                 /* RTC_ALM_SET alarms may be up to 24 hours in the future.
281                  * Rather than expecting every RTC to implement "don't care"
282                  * for day/month/year fields, just force the alarm to have
283                  * the right values for those fields.
284                  *
285                  * RTC_WKALM_SET should be used instead.  Not only does it
286                  * eliminate the need for a separate RTC_AIE_ON call, it
287                  * doesn't have the "alarm 23:59:59 in the future" race.
288                  *
289                  * NOTE:  some legacy code may have used invalid fields as
290                  * wildcards, exposing hardware "periodic alarm" capabilities.
291                  * Not supported here.
292                  */
293                 {
294                         unsigned long now, then;
295
296                         err = rtc_read_time(rtc, &tm);
297                         if (err < 0)
298                                 return err;
299                         rtc_tm_to_time(&tm, &now);
300
301                         alarm.time.tm_mday = tm.tm_mday;
302                         alarm.time.tm_mon = tm.tm_mon;
303                         alarm.time.tm_year = tm.tm_year;
304                         err  = rtc_valid_tm(&alarm.time);
305                         if (err < 0)
306                                 return err;
307                         rtc_tm_to_time(&alarm.time, &then);
308
309                         /* alarm may need to wrap into tomorrow */
310                         if (then < now) {
311                                 rtc_time_to_tm(now + 24 * 60 * 60, &tm);
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                         }
316                 }
317
318                 err = rtc_set_alarm(rtc, &alarm);
319                 break;
320
321         case RTC_RD_TIME:
322                 err = rtc_read_time(rtc, &tm);
323                 if (err < 0)
324                         return err;
325
326                 if (copy_to_user(uarg, &tm, sizeof(tm)))
327                         return -EFAULT;
328                 break;
329
330         case RTC_SET_TIME:
331                 if (copy_from_user(&tm, uarg, sizeof(tm)))
332                         return -EFAULT;
333
334                 err = rtc_set_time(rtc, &tm);
335                 break;
336
337         case RTC_PIE_ON:
338                 err = rtc_irq_set_state(rtc, NULL, 1);
339                 break;
340
341         case RTC_PIE_OFF:
342                 err = rtc_irq_set_state(rtc, NULL, 0);
343                 break;
344
345         case RTC_IRQP_SET:
346                 err = rtc_irq_set_freq(rtc, NULL, arg);
347                 break;
348
349         case RTC_IRQP_READ:
350                 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
351                 break;
352
353 #if 0
354         case RTC_EPOCH_SET:
355 #ifndef rtc_epoch
356                 /*
357                  * There were no RTC clocks before 1900.
358                  */
359                 if (arg < 1900) {
360                         err = -EINVAL;
361                         break;
362                 }
363                 rtc_epoch = arg;
364                 err = 0;
365 #endif
366                 break;
367
368         case RTC_EPOCH_READ:
369                 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
370                 break;
371 #endif
372         case RTC_WKALM_SET:
373                 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
374                         return -EFAULT;
375
376                 err = rtc_set_alarm(rtc, &alarm);
377                 break;
378
379         case RTC_WKALM_RD:
380                 err = rtc_read_alarm(rtc, &alarm);
381                 if (err < 0)
382                         return err;
383
384                 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
385                         return -EFAULT;
386                 break;
387
388 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
389         case RTC_UIE_OFF:
390                 clear_uie(rtc);
391                 return 0;
392
393         case RTC_UIE_ON:
394                 return set_uie(rtc);
395 #endif
396         default:
397                 err = -ENOTTY;
398                 break;
399         }
400
401         return err;
402 }
403
404 static int rtc_dev_release(struct inode *inode, struct file *file)
405 {
406         struct rtc_device *rtc = file->private_data;
407
408 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
409         clear_uie(rtc);
410 #endif
411         if (rtc->ops->release)
412                 rtc->ops->release(rtc->dev.parent);
413
414         clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
415         return 0;
416 }
417
418 static int rtc_dev_fasync(int fd, struct file *file, int on)
419 {
420         struct rtc_device *rtc = file->private_data;
421         return fasync_helper(fd, file, on, &rtc->async_queue);
422 }
423
424 static const struct file_operations rtc_dev_fops = {
425         .owner          = THIS_MODULE,
426         .llseek         = no_llseek,
427         .read           = rtc_dev_read,
428         .poll           = rtc_dev_poll,
429         .ioctl          = rtc_dev_ioctl,
430         .open           = rtc_dev_open,
431         .release        = rtc_dev_release,
432         .fasync         = rtc_dev_fasync,
433 };
434
435 /* insertion/removal hooks */
436
437 void rtc_dev_prepare(struct rtc_device *rtc)
438 {
439         if (!rtc_devt)
440                 return;
441
442         if (rtc->id >= RTC_DEV_MAX) {
443                 pr_debug("%s: too many RTC devices\n", rtc->name);
444                 return;
445         }
446
447         rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
448
449 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
450         INIT_WORK(&rtc->uie_task, rtc_uie_task);
451         setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
452 #endif
453
454         cdev_init(&rtc->char_dev, &rtc_dev_fops);
455         rtc->char_dev.owner = rtc->owner;
456 }
457
458 void rtc_dev_add_device(struct rtc_device *rtc)
459 {
460         if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))
461                 printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
462                         rtc->name, MAJOR(rtc_devt), rtc->id);
463         else
464                 pr_debug("%s: dev (%d:%d)\n", rtc->name,
465                         MAJOR(rtc_devt), rtc->id);
466 }
467
468 void rtc_dev_del_device(struct rtc_device *rtc)
469 {
470         if (rtc->dev.devt)
471                 cdev_del(&rtc->char_dev);
472 }
473
474 void __init rtc_dev_init(void)
475 {
476         int err;
477
478         err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
479         if (err < 0)
480                 printk(KERN_ERR "%s: failed to allocate char dev region\n",
481                         __FILE__);
482 }
483
484 void __exit rtc_dev_exit(void)
485 {
486         if (rtc_devt)
487                 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
488 }