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Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / drivers / rtc / rtc-dev.c
blob90dfa0df747acb9314b4ed115c2eec0dee1eae0d
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 }
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