[PATCH] RTC: rtc-dev UIE emulation
[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         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         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         /* avoid conflicting IRQ users */
218         if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
219                 spin_lock(&rtc->irq_task_lock);
220                 if (rtc->irq_task)
221                         err = -EBUSY;
222                 spin_unlock(&rtc->irq_task_lock);
223
224                 if (err < 0)
225                         return err;
226         }
227
228         /* try the driver's ioctl interface */
229         if (ops->ioctl) {
230                 err = ops->ioctl(class_dev->dev, cmd, arg);
231                 if (err != -ENOIOCTLCMD)
232                         return err;
233         }
234
235         /* if the driver does not provide the ioctl interface
236          * or if that particular ioctl was not implemented
237          * (-ENOIOCTLCMD), we will try to emulate here.
238          */
239
240         switch (cmd) {
241         case RTC_ALM_READ:
242                 err = rtc_read_alarm(class_dev, &alarm);
243                 if (err < 0)
244                         return err;
245
246                 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
247                         return -EFAULT;
248                 break;
249
250         case RTC_ALM_SET:
251                 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
252                         return -EFAULT;
253
254                 alarm.enabled = 0;
255                 alarm.pending = 0;
256                 alarm.time.tm_mday = -1;
257                 alarm.time.tm_mon = -1;
258                 alarm.time.tm_year = -1;
259                 alarm.time.tm_wday = -1;
260                 alarm.time.tm_yday = -1;
261                 alarm.time.tm_isdst = -1;
262                 err = rtc_set_alarm(class_dev, &alarm);
263                 break;
264
265         case RTC_RD_TIME:
266                 err = rtc_read_time(class_dev, &tm);
267                 if (err < 0)
268                         return err;
269
270                 if (copy_to_user(uarg, &tm, sizeof(tm)))
271                         return -EFAULT;
272                 break;
273
274         case RTC_SET_TIME:
275                 if (!capable(CAP_SYS_TIME))
276                         return -EACCES;
277
278                 if (copy_from_user(&tm, uarg, sizeof(tm)))
279                         return -EFAULT;
280
281                 err = rtc_set_time(class_dev, &tm);
282                 break;
283 #if 0
284         case RTC_EPOCH_SET:
285 #ifndef rtc_epoch
286                 /*
287                  * There were no RTC clocks before 1900.
288                  */
289                 if (arg < 1900) {
290                         err = -EINVAL;
291                         break;
292                 }
293                 if (!capable(CAP_SYS_TIME)) {
294                         err = -EACCES;
295                         break;
296                 }
297                 rtc_epoch = arg;
298                 err = 0;
299 #endif
300                 break;
301
302         case RTC_EPOCH_READ:
303                 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
304                 break;
305 #endif
306         case RTC_WKALM_SET:
307                 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
308                         return -EFAULT;
309
310                 err = rtc_set_alarm(class_dev, &alarm);
311                 break;
312
313         case RTC_WKALM_RD:
314                 err = rtc_read_alarm(class_dev, &alarm);
315                 if (err < 0)
316                         return err;
317
318                 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
319                         return -EFAULT;
320                 break;
321
322 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
323         case RTC_UIE_OFF:
324                 clear_uie(rtc);
325                 return 0;
326
327         case RTC_UIE_ON:
328                 return set_uie(rtc);
329 #endif
330         default:
331                 err = -ENOTTY;
332                 break;
333         }
334
335         return err;
336 }
337
338 static int rtc_dev_release(struct inode *inode, struct file *file)
339 {
340         struct rtc_device *rtc = to_rtc_device(file->private_data);
341
342 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
343         clear_uie(rtc);
344 #endif
345         if (rtc->ops->release)
346                 rtc->ops->release(rtc->class_dev.dev);
347
348         mutex_unlock(&rtc->char_lock);
349         return 0;
350 }
351
352 static int rtc_dev_fasync(int fd, struct file *file, int on)
353 {
354         struct rtc_device *rtc = to_rtc_device(file->private_data);
355         return fasync_helper(fd, file, on, &rtc->async_queue);
356 }
357
358 static struct file_operations rtc_dev_fops = {
359         .owner          = THIS_MODULE,
360         .llseek         = no_llseek,
361         .read           = rtc_dev_read,
362         .poll           = rtc_dev_poll,
363         .ioctl          = rtc_dev_ioctl,
364         .open           = rtc_dev_open,
365         .release        = rtc_dev_release,
366         .fasync         = rtc_dev_fasync,
367 };
368
369 /* insertion/removal hooks */
370
371 static int rtc_dev_add_device(struct class_device *class_dev,
372                                 struct class_interface *class_intf)
373 {
374         int err = 0;
375         struct rtc_device *rtc = to_rtc_device(class_dev);
376
377         if (rtc->id >= RTC_DEV_MAX) {
378                 dev_err(class_dev->dev, "too many RTCs\n");
379                 return -EINVAL;
380         }
381
382         mutex_init(&rtc->char_lock);
383         spin_lock_init(&rtc->irq_lock);
384         init_waitqueue_head(&rtc->irq_queue);
385 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
386         INIT_WORK(&rtc->uie_task, rtc_uie_task, rtc);
387         setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
388 #endif
389
390         cdev_init(&rtc->char_dev, &rtc_dev_fops);
391         rtc->char_dev.owner = rtc->owner;
392
393         if (cdev_add(&rtc->char_dev, MKDEV(MAJOR(rtc_devt), rtc->id), 1)) {
394                 cdev_del(&rtc->char_dev);
395                 dev_err(class_dev->dev,
396                         "failed to add char device %d:%d\n",
397                         MAJOR(rtc_devt), rtc->id);
398                 return -ENODEV;
399         }
400
401         rtc->rtc_dev = class_device_create(rtc_dev_class, NULL,
402                                                 MKDEV(MAJOR(rtc_devt), rtc->id),
403                                                 class_dev->dev, "rtc%d", rtc->id);
404         if (IS_ERR(rtc->rtc_dev)) {
405                 dev_err(class_dev->dev, "cannot create rtc_dev device\n");
406                 err = PTR_ERR(rtc->rtc_dev);
407                 goto err_cdev_del;
408         }
409
410         dev_info(class_dev->dev, "rtc intf: dev (%d:%d)\n",
411                 MAJOR(rtc->rtc_dev->devt),
412                 MINOR(rtc->rtc_dev->devt));
413
414         return 0;
415
416 err_cdev_del:
417
418         cdev_del(&rtc->char_dev);
419         return err;
420 }
421
422 static void rtc_dev_remove_device(struct class_device *class_dev,
423                                         struct class_interface *class_intf)
424 {
425         struct rtc_device *rtc = to_rtc_device(class_dev);
426
427         if (rtc->rtc_dev) {
428                 dev_dbg(class_dev->dev, "removing char %d:%d\n",
429                         MAJOR(rtc->rtc_dev->devt),
430                         MINOR(rtc->rtc_dev->devt));
431
432                 class_device_unregister(rtc->rtc_dev);
433                 cdev_del(&rtc->char_dev);
434         }
435 }
436
437 /* interface registration */
438
439 static struct class_interface rtc_dev_interface = {
440         .add = &rtc_dev_add_device,
441         .remove = &rtc_dev_remove_device,
442 };
443
444 static int __init rtc_dev_init(void)
445 {
446         int err;
447
448         rtc_dev_class = class_create(THIS_MODULE, "rtc-dev");
449         if (IS_ERR(rtc_dev_class))
450                 return PTR_ERR(rtc_dev_class);
451
452         err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
453         if (err < 0) {
454                 printk(KERN_ERR "%s: failed to allocate char dev region\n",
455                         __FILE__);
456                 goto err_destroy_class;
457         }
458
459         err = rtc_interface_register(&rtc_dev_interface);
460         if (err < 0) {
461                 printk(KERN_ERR "%s: failed to register the interface\n",
462                         __FILE__);
463                 goto err_unregister_chrdev;
464         }
465
466         return 0;
467
468 err_unregister_chrdev:
469         unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
470
471 err_destroy_class:
472         class_destroy(rtc_dev_class);
473
474         return err;
475 }
476
477 static void __exit rtc_dev_exit(void)
478 {
479         class_interface_unregister(&rtc_dev_interface);
480         class_destroy(rtc_dev_class);
481         unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
482 }
483
484 module_init(rtc_dev_init);
485 module_exit(rtc_dev_exit);
486
487 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
488 MODULE_DESCRIPTION("RTC class dev interface");
489 MODULE_LICENSE("GPL");