[PATCH] rtc framework handles periodic irqs
[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
17 static struct class *rtc_dev_class;
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         /* We keep the lock as long as the device is in use
30          * and return immediately if busy
31          */
32         if (!(mutex_trylock(&rtc->char_lock)))
33                 return -EBUSY;
34
35         file->private_data = &rtc->class_dev;
36
37         err = ops->open ? ops->open(rtc->class_dev.dev) : 0;
38         if (err == 0) {
39                 spin_lock_irq(&rtc->irq_lock);
40                 rtc->irq_data = 0;
41                 spin_unlock_irq(&rtc->irq_lock);
42
43                 return 0;
44         }
45
46         /* something has gone wrong, release the lock */
47         mutex_unlock(&rtc->char_lock);
48         return err;
49 }
50
51 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
52 /*
53  * Routine to poll RTC seconds field for change as often as possible,
54  * after first RTC_UIE use timer to reduce polling
55  */
56 static void rtc_uie_task(void *data)
57 {
58         struct rtc_device *rtc = data;
59         struct rtc_time tm;
60         int num = 0;
61         int err;
62
63         err = rtc_read_time(&rtc->class_dev, &tm);
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_update_irq(&rtc->class_dev, num, RTC_UF | RTC_IRQF);
80 }
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->class_dev, &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 = to_rtc_device(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->class_dev.dev,
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 = to_rtc_device(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 class_device *class_dev = file->private_data;
211         struct rtc_device *rtc = to_rtc_device(class_dev);
212         const struct rtc_class_ops *ops = rtc->ops;
213         struct rtc_time tm;
214         struct rtc_wkalrm alarm;
215         void __user *uarg = (void __user *) arg;
216
217         /* check that the calling task has appropriate permissions
218          * for certain ioctls. doing this check here is useful
219          * to avoid duplicate code in each driver.
220          */
221         switch (cmd) {
222         case RTC_EPOCH_SET:
223         case RTC_SET_TIME:
224                 if (!capable(CAP_SYS_TIME))
225                         return -EACCES;
226                 break;
227
228         case RTC_IRQP_SET:
229                 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
230                         return -EACCES;
231                 break;
232
233         case RTC_PIE_ON:
234                 if (!capable(CAP_SYS_RESOURCE))
235                         return -EACCES;
236                 break;
237         }
238
239         /* avoid conflicting IRQ users */
240         if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
241                 spin_lock(&rtc->irq_task_lock);
242                 if (rtc->irq_task)
243                         err = -EBUSY;
244                 spin_unlock(&rtc->irq_task_lock);
245
246                 if (err < 0)
247                         return err;
248         }
249
250         /* try the driver's ioctl interface */
251         if (ops->ioctl) {
252                 err = ops->ioctl(class_dev->dev, cmd, arg);
253                 if (err != -ENOIOCTLCMD)
254                         return err;
255         }
256
257         /* if the driver does not provide the ioctl interface
258          * or if that particular ioctl was not implemented
259          * (-ENOIOCTLCMD), we will try to emulate here.
260          */
261
262         switch (cmd) {
263         case RTC_ALM_READ:
264                 err = rtc_read_alarm(class_dev, &alarm);
265                 if (err < 0)
266                         return err;
267
268                 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
269                         return -EFAULT;
270                 break;
271
272         case RTC_ALM_SET:
273                 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
274                         return -EFAULT;
275
276                 alarm.enabled = 0;
277                 alarm.pending = 0;
278                 alarm.time.tm_mday = -1;
279                 alarm.time.tm_mon = -1;
280                 alarm.time.tm_year = -1;
281                 alarm.time.tm_wday = -1;
282                 alarm.time.tm_yday = -1;
283                 alarm.time.tm_isdst = -1;
284                 err = rtc_set_alarm(class_dev, &alarm);
285                 break;
286
287         case RTC_RD_TIME:
288                 err = rtc_read_time(class_dev, &tm);
289                 if (err < 0)
290                         return err;
291
292                 if (copy_to_user(uarg, &tm, sizeof(tm)))
293                         return -EFAULT;
294                 break;
295
296         case RTC_SET_TIME:
297                 if (copy_from_user(&tm, uarg, sizeof(tm)))
298                         return -EFAULT;
299
300                 err = rtc_set_time(class_dev, &tm);
301                 break;
302
303         case RTC_IRQP_READ:
304                 if (ops->irq_set_freq)
305                         err = put_user(rtc->irq_freq, (unsigned long *) arg);
306                 break;
307
308         case RTC_IRQP_SET:
309                 if (ops->irq_set_freq)
310                         err = rtc_irq_set_freq(class_dev, rtc->irq_task, arg);
311                 break;
312
313 #if 0
314         case RTC_EPOCH_SET:
315 #ifndef rtc_epoch
316                 /*
317                  * There were no RTC clocks before 1900.
318                  */
319                 if (arg < 1900) {
320                         err = -EINVAL;
321                         break;
322                 }
323                 rtc_epoch = arg;
324                 err = 0;
325 #endif
326                 break;
327
328         case RTC_EPOCH_READ:
329                 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
330                 break;
331 #endif
332         case RTC_WKALM_SET:
333                 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
334                         return -EFAULT;
335
336                 err = rtc_set_alarm(class_dev, &alarm);
337                 break;
338
339         case RTC_WKALM_RD:
340                 err = rtc_read_alarm(class_dev, &alarm);
341                 if (err < 0)
342                         return err;
343
344                 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
345                         return -EFAULT;
346                 break;
347
348 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
349         case RTC_UIE_OFF:
350                 clear_uie(rtc);
351                 return 0;
352
353         case RTC_UIE_ON:
354                 return set_uie(rtc);
355 #endif
356         default:
357                 err = -ENOTTY;
358                 break;
359         }
360
361         return err;
362 }
363
364 static int rtc_dev_release(struct inode *inode, struct file *file)
365 {
366         struct rtc_device *rtc = to_rtc_device(file->private_data);
367
368 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
369         clear_uie(rtc);
370 #endif
371         if (rtc->ops->release)
372                 rtc->ops->release(rtc->class_dev.dev);
373
374         mutex_unlock(&rtc->char_lock);
375         return 0;
376 }
377
378 static int rtc_dev_fasync(int fd, struct file *file, int on)
379 {
380         struct rtc_device *rtc = to_rtc_device(file->private_data);
381         return fasync_helper(fd, file, on, &rtc->async_queue);
382 }
383
384 static struct file_operations rtc_dev_fops = {
385         .owner          = THIS_MODULE,
386         .llseek         = no_llseek,
387         .read           = rtc_dev_read,
388         .poll           = rtc_dev_poll,
389         .ioctl          = rtc_dev_ioctl,
390         .open           = rtc_dev_open,
391         .release        = rtc_dev_release,
392         .fasync         = rtc_dev_fasync,
393 };
394
395 /* insertion/removal hooks */
396
397 static int rtc_dev_add_device(struct class_device *class_dev,
398                                 struct class_interface *class_intf)
399 {
400         int err = 0;
401         struct rtc_device *rtc = to_rtc_device(class_dev);
402
403         if (rtc->id >= RTC_DEV_MAX) {
404                 dev_err(class_dev->dev, "too many RTCs\n");
405                 return -EINVAL;
406         }
407
408         mutex_init(&rtc->char_lock);
409         spin_lock_init(&rtc->irq_lock);
410         init_waitqueue_head(&rtc->irq_queue);
411 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
412         INIT_WORK(&rtc->uie_task, rtc_uie_task, rtc);
413         setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
414 #endif
415
416         cdev_init(&rtc->char_dev, &rtc_dev_fops);
417         rtc->char_dev.owner = rtc->owner;
418
419         if (cdev_add(&rtc->char_dev, MKDEV(MAJOR(rtc_devt), rtc->id), 1)) {
420                 dev_err(class_dev->dev,
421                         "failed to add char device %d:%d\n",
422                         MAJOR(rtc_devt), rtc->id);
423                 return -ENODEV;
424         }
425
426         rtc->rtc_dev = class_device_create(rtc_dev_class, NULL,
427                                                 MKDEV(MAJOR(rtc_devt), rtc->id),
428                                                 class_dev->dev, "rtc%d", rtc->id);
429         if (IS_ERR(rtc->rtc_dev)) {
430                 dev_err(class_dev->dev, "cannot create rtc_dev device\n");
431                 err = PTR_ERR(rtc->rtc_dev);
432                 goto err_cdev_del;
433         }
434
435         dev_info(class_dev->dev, "rtc intf: dev (%d:%d)\n",
436                 MAJOR(rtc->rtc_dev->devt),
437                 MINOR(rtc->rtc_dev->devt));
438
439         return 0;
440
441 err_cdev_del:
442
443         cdev_del(&rtc->char_dev);
444         return err;
445 }
446
447 static void rtc_dev_remove_device(struct class_device *class_dev,
448                                         struct class_interface *class_intf)
449 {
450         struct rtc_device *rtc = to_rtc_device(class_dev);
451
452         if (rtc->rtc_dev) {
453                 dev_dbg(class_dev->dev, "removing char %d:%d\n",
454                         MAJOR(rtc->rtc_dev->devt),
455                         MINOR(rtc->rtc_dev->devt));
456
457                 class_device_unregister(rtc->rtc_dev);
458                 cdev_del(&rtc->char_dev);
459         }
460 }
461
462 /* interface registration */
463
464 static struct class_interface rtc_dev_interface = {
465         .add = &rtc_dev_add_device,
466         .remove = &rtc_dev_remove_device,
467 };
468
469 static int __init rtc_dev_init(void)
470 {
471         int err;
472
473         rtc_dev_class = class_create(THIS_MODULE, "rtc-dev");
474         if (IS_ERR(rtc_dev_class))
475                 return PTR_ERR(rtc_dev_class);
476
477         err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
478         if (err < 0) {
479                 printk(KERN_ERR "%s: failed to allocate char dev region\n",
480                         __FILE__);
481                 goto err_destroy_class;
482         }
483
484         err = rtc_interface_register(&rtc_dev_interface);
485         if (err < 0) {
486                 printk(KERN_ERR "%s: failed to register the interface\n",
487                         __FILE__);
488                 goto err_unregister_chrdev;
489         }
490
491         return 0;
492
493 err_unregister_chrdev:
494         unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
495
496 err_destroy_class:
497         class_destroy(rtc_dev_class);
498
499         return err;
500 }
501
502 static void __exit rtc_dev_exit(void)
503 {
504         class_interface_unregister(&rtc_dev_interface);
505         class_destroy(rtc_dev_class);
506         unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
507 }
508
509 subsys_initcall(rtc_dev_init);
510 module_exit(rtc_dev_exit);
511
512 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
513 MODULE_DESCRIPTION("RTC class dev interface");
514 MODULE_LICENSE("GPL");