projects/linux·blob v2.6.21 · refs

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1/*
2 * RTC subsystem, dev interface
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <[email protected]>
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
17static struct class *rtc_dev_class;
18static dev_t rtc_devt;
19
20#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
21
22static 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 */
56static void rtc_uie_task(struct work_struct *work)
57{
58 struct rtc_device *rtc =
59 container_of(work, struct rtc_device, uie_task);
60 struct rtc_time tm;
61 int num = 0;
62 int err;
63
64 err = rtc_read_time(&rtc->class_dev, &tm);
65
66 local_irq_disable();
67 spin_lock(&rtc->irq_lock);
68 if (rtc->stop_uie_polling || err) {
69 rtc->uie_task_active = 0;
70 } else if (rtc->oldsecs != tm.tm_sec) {
71 num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
72 rtc->oldsecs = tm.tm_sec;
73 rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
74 rtc->uie_timer_active = 1;
75 rtc->uie_task_active = 0;
76 add_timer(&rtc->uie_timer);
77 } else if (schedule_work(&rtc->uie_task) == 0) {
78 rtc->uie_task_active = 0;
79 }
80 spin_unlock(&rtc->irq_lock);
81 if (num)
82 rtc_update_irq(&rtc->class_dev, num, RTC_UF | RTC_IRQF);
83 local_irq_enable();
84}
85static void rtc_uie_timer(unsigned long data)
86{
87 struct rtc_device *rtc = (struct rtc_device *)data;
88 unsigned long flags;
89
90 spin_lock_irqsave(&rtc->irq_lock, flags);
91 rtc->uie_timer_active = 0;
92 rtc->uie_task_active = 1;
93 if ((schedule_work(&rtc->uie_task) == 0))
94 rtc->uie_task_active = 0;
95 spin_unlock_irqrestore(&rtc->irq_lock, flags);
96}
97
98static void clear_uie(struct rtc_device *rtc)
99{
100 spin_lock_irq(&rtc->irq_lock);
101 if (rtc->irq_active) {
102 rtc->stop_uie_polling = 1;
103 if (rtc->uie_timer_active) {
104 spin_unlock_irq(&rtc->irq_lock);
105 del_timer_sync(&rtc->uie_timer);
106 spin_lock_irq(&rtc->irq_lock);
107 rtc->uie_timer_active = 0;
108 }
109 if (rtc->uie_task_active) {
110 spin_unlock_irq(&rtc->irq_lock);
111 flush_scheduled_work();
112 spin_lock_irq(&rtc->irq_lock);
113 }
114 rtc->irq_active = 0;
115 }
116 spin_unlock_irq(&rtc->irq_lock);
117}
118
119static int set_uie(struct rtc_device *rtc)
120{
121 struct rtc_time tm;
122 int err;
123
124 err = rtc_read_time(&rtc->class_dev, &tm);
125 if (err)
126 return err;
127 spin_lock_irq(&rtc->irq_lock);
128 if (!rtc->irq_active) {
129 rtc->irq_active = 1;
130 rtc->stop_uie_polling = 0;
131 rtc->oldsecs = tm.tm_sec;
132 rtc->uie_task_active = 1;
133 if (schedule_work(&rtc->uie_task) == 0)
134 rtc->uie_task_active = 0;
135 }
136 rtc->irq_data = 0;
137 spin_unlock_irq(&rtc->irq_lock);
138 return 0;
139}
140#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
141
142static ssize_t
143rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
144{
145 struct rtc_device *rtc = to_rtc_device(file->private_data);
146
147 DECLARE_WAITQUEUE(wait, current);
148 unsigned long data;
149 ssize_t ret;
150
151 if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
152 return -EINVAL;
153
154 add_wait_queue(&rtc->irq_queue, &wait);
155 do {
156 __set_current_state(TASK_INTERRUPTIBLE);
157
158 spin_lock_irq(&rtc->irq_lock);
159 data = rtc->irq_data;
160 rtc->irq_data = 0;
161 spin_unlock_irq(&rtc->irq_lock);
162
163 if (data != 0) {
164 ret = 0;
165 break;
166 }
167 if (file->f_flags & O_NONBLOCK) {
168 ret = -EAGAIN;
169 break;
170 }
171 if (signal_pending(current)) {
172 ret = -ERESTARTSYS;
173 break;
174 }
175 schedule();
176 } while (1);
177 set_current_state(TASK_RUNNING);
178 remove_wait_queue(&rtc->irq_queue, &wait);
179
180 if (ret == 0) {
181 /* Check for any data updates */
182 if (rtc->ops->read_callback)
183 data = rtc->ops->read_callback(rtc->class_dev.dev,
184 data);
185
186 if (sizeof(int) != sizeof(long) &&
187 count == sizeof(unsigned int))
188 ret = put_user(data, (unsigned int __user *)buf) ?:
189 sizeof(unsigned int);
190 else
191 ret = put_user(data, (unsigned long __user *)buf) ?:
192 sizeof(unsigned long);
193 }
194 return ret;
195}
196
197static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
198{
199 struct rtc_device *rtc = to_rtc_device(file->private_data);
200 unsigned long data;
201
202 poll_wait(file, &rtc->irq_queue, wait);
203
204 data = rtc->irq_data;
205
206 return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
207}
208
209static int rtc_dev_ioctl(struct inode *inode, struct file *file,
210 unsigned int cmd, unsigned long arg)
211{
212 int err = 0;
213 struct class_device *class_dev = file->private_data;
214 struct rtc_device *rtc = to_rtc_device(class_dev);
215 const struct rtc_class_ops *ops = rtc->ops;
216 struct rtc_time tm;
217 struct rtc_wkalrm alarm;
218 void __user *uarg = (void __user *) arg;
219
220 /* check that the calling task has appropriate permissions
221 * for certain ioctls. doing this check here is useful
222 * to avoid duplicate code in each driver.
223 */
224 switch (cmd) {
225 case RTC_EPOCH_SET:
226 case RTC_SET_TIME:
227 if (!capable(CAP_SYS_TIME))
228 return -EACCES;
229 break;
230
231 case RTC_IRQP_SET:
232 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
233 return -EACCES;
234 break;
235
236 case RTC_PIE_ON:
237 if (!capable(CAP_SYS_RESOURCE))
238 return -EACCES;
239 break;
240 }
241
242 /* avoid conflicting IRQ users */
243 if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
244 spin_lock_irq(&rtc->irq_task_lock);
245 if (rtc->irq_task)
246 err = -EBUSY;
247 spin_unlock_irq(&rtc->irq_task_lock);
248
249 if (err < 0)
250 return err;
251 }
252
253 /* try the driver's ioctl interface */
254 if (ops->ioctl) {
255 err = ops->ioctl(class_dev->dev, cmd, arg);
256 if (err != -ENOIOCTLCMD)
257 return err;
258 }
259
260 /* if the driver does not provide the ioctl interface
261 * or if that particular ioctl was not implemented
262 * (-ENOIOCTLCMD), we will try to emulate here.
263 */
264
265 switch (cmd) {
266 case RTC_ALM_READ:
267 err = rtc_read_alarm(class_dev, &alarm);
268 if (err < 0)
269 return err;
270
271 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
272 return -EFAULT;
273 break;
274
275 case RTC_ALM_SET:
276 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
277 return -EFAULT;
278
279 alarm.enabled = 0;
280 alarm.pending = 0;
281 alarm.time.tm_mday = -1;
282 alarm.time.tm_mon = -1;
283 alarm.time.tm_year = -1;
284 alarm.time.tm_wday = -1;
285 alarm.time.tm_yday = -1;
286 alarm.time.tm_isdst = -1;
287 err = rtc_set_alarm(class_dev, &alarm);
288 break;
289
290 case RTC_RD_TIME:
291 err = rtc_read_time(class_dev, &tm);
292 if (err < 0)
293 return err;
294
295 if (copy_to_user(uarg, &tm, sizeof(tm)))
296 return -EFAULT;
297 break;
298
299 case RTC_SET_TIME:
300 if (copy_from_user(&tm, uarg, sizeof(tm)))
301 return -EFAULT;
302
303 err = rtc_set_time(class_dev, &tm);
304 break;
305
306 case RTC_IRQP_READ:
307 if (ops->irq_set_freq)
308 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
309 break;
310
311 case RTC_IRQP_SET:
312 if (ops->irq_set_freq)
313 err = rtc_irq_set_freq(class_dev, rtc->irq_task, arg);
314 break;
315
316#if 0
317 case RTC_EPOCH_SET:
318#ifndef rtc_epoch
319 /*
320 * There were no RTC clocks before 1900.
321 */
322 if (arg < 1900) {
323 err = -EINVAL;
324 break;
325 }
326 rtc_epoch = arg;
327 err = 0;
328#endif
329 break;
330
331 case RTC_EPOCH_READ:
332 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
333 break;
334#endif
335 case RTC_WKALM_SET:
336 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
337 return -EFAULT;
338
339 err = rtc_set_alarm(class_dev, &alarm);
340 break;
341
342 case RTC_WKALM_RD:
343 err = rtc_read_alarm(class_dev, &alarm);
344 if (err < 0)
345 return err;
346
347 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
348 return -EFAULT;
349 break;
350
351#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
352 case RTC_UIE_OFF:
353 clear_uie(rtc);
354 return 0;
355
356 case RTC_UIE_ON:
357 return set_uie(rtc);
358#endif
359 default:
360 err = -ENOTTY;
361 break;
362 }
363
364 return err;
365}
366
367static int rtc_dev_release(struct inode *inode, struct file *file)
368{
369 struct rtc_device *rtc = to_rtc_device(file->private_data);
370
371#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
372 clear_uie(rtc);
373#endif
374 if (rtc->ops->release)
375 rtc->ops->release(rtc->class_dev.dev);
376
377 mutex_unlock(&rtc->char_lock);
378 return 0;
379}
380
381static int rtc_dev_fasync(int fd, struct file *file, int on)
382{
383 struct rtc_device *rtc = to_rtc_device(file->private_data);
384 return fasync_helper(fd, file, on, &rtc->async_queue);
385}
386
387static const struct file_operations rtc_dev_fops = {
388 .owner = THIS_MODULE,
389 .llseek = no_llseek,
390 .read = rtc_dev_read,
391 .poll = rtc_dev_poll,
392 .ioctl = rtc_dev_ioctl,
393 .open = rtc_dev_open,
394 .release = rtc_dev_release,
395 .fasync = rtc_dev_fasync,
396};
397
398/* insertion/removal hooks */
399
400static int rtc_dev_add_device(struct class_device *class_dev,
401 struct class_interface *class_intf)
402{
403 int err = 0;
404 struct rtc_device *rtc = to_rtc_device(class_dev);
405
406 if (rtc->id >= RTC_DEV_MAX) {
407 dev_err(class_dev->dev, "too many RTCs\n");
408 return -EINVAL;
409 }
410
411 mutex_init(&rtc->char_lock);
412 spin_lock_init(&rtc->irq_lock);
413 init_waitqueue_head(&rtc->irq_queue);
414#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
415 INIT_WORK(&rtc->uie_task, rtc_uie_task);
416 setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
417#endif
418
419 cdev_init(&rtc->char_dev, &rtc_dev_fops);
420 rtc->char_dev.owner = rtc->owner;
421
422 if (cdev_add(&rtc->char_dev, MKDEV(MAJOR(rtc_devt), rtc->id), 1)) {
423 dev_err(class_dev->dev,
424 "failed to add char device %d:%d\n",
425 MAJOR(rtc_devt), rtc->id);
426 return -ENODEV;
427 }
428
429 rtc->rtc_dev = class_device_create(rtc_dev_class, NULL,
430 MKDEV(MAJOR(rtc_devt), rtc->id),
431 class_dev->dev, "rtc%d", rtc->id);
432 if (IS_ERR(rtc->rtc_dev)) {
433 dev_err(class_dev->dev, "cannot create rtc_dev device\n");
434 err = PTR_ERR(rtc->rtc_dev);
435 goto err_cdev_del;
436 }
437
438 dev_dbg(class_dev->dev, "rtc intf: dev (%d:%d)\n",
439 MAJOR(rtc->rtc_dev->devt),
440 MINOR(rtc->rtc_dev->devt));
441
442 return 0;
443
444err_cdev_del:
445
446 cdev_del(&rtc->char_dev);
447 return err;
448}
449
450static void rtc_dev_remove_device(struct class_device *class_dev,
451 struct class_interface *class_intf)
452{
453 struct rtc_device *rtc = to_rtc_device(class_dev);
454
455 if (rtc->rtc_dev) {
456 dev_dbg(class_dev->dev, "removing char %d:%d\n",
457 MAJOR(rtc->rtc_dev->devt),
458 MINOR(rtc->rtc_dev->devt));
459
460 class_device_unregister(rtc->rtc_dev);
461 cdev_del(&rtc->char_dev);
462 }
463}
464
465/* interface registration */
466
467static struct class_interface rtc_dev_interface = {
468 .add = &rtc_dev_add_device,
469 .remove = &rtc_dev_remove_device,
470};
471
472static int __init rtc_dev_init(void)
473{
474 int err;
475
476 rtc_dev_class = class_create(THIS_MODULE, "rtc-dev");
477 if (IS_ERR(rtc_dev_class))
478 return PTR_ERR(rtc_dev_class);
479
480 err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
481 if (err < 0) {
482 printk(KERN_ERR "%s: failed to allocate char dev region\n",
483 __FILE__);
484 goto err_destroy_class;
485 }
486
487 err = rtc_interface_register(&rtc_dev_interface);
488 if (err < 0) {
489 printk(KERN_ERR "%s: failed to register the interface\n",
490 __FILE__);
491 goto err_unregister_chrdev;
492 }
493
494 return 0;
495
496err_unregister_chrdev:
497 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
498
499err_destroy_class:
500 class_destroy(rtc_dev_class);
501
502 return err;
503}
504
505static void __exit rtc_dev_exit(void)
506{
507 class_interface_unregister(&rtc_dev_interface);
508 class_destroy(rtc_dev_class);
509 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
510}
511
512subsys_initcall(rtc_dev_init);
513module_exit(rtc_dev_exit);
514
515MODULE_AUTHOR("Alessandro Zummo <[email protected]>");
516MODULE_DESCRIPTION("RTC class dev interface");
517MODULE_LICENSE("GPL");