2 * RTC subsystem, dev interface
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 * based on arch/arm/common/rtctime.c
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.
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 #include <linux/module.h>
17 #include <linux/rtc.h>
18 #include <linux/sched/signal.h>
21 static dev_t rtc_devt;
23 #define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
25 static int rtc_dev_open(struct inode *inode, struct file *file)
27 struct rtc_device *rtc = container_of(inode->i_cdev,
28 struct rtc_device, char_dev);
30 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
33 file->private_data = rtc;
35 spin_lock_irq(&rtc->irq_lock);
37 spin_unlock_irq(&rtc->irq_lock);
42 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
44 * Routine to poll RTC seconds field for change as often as possible,
45 * after first RTC_UIE use timer to reduce polling
47 static void rtc_uie_task(struct work_struct *work)
49 struct rtc_device *rtc =
50 container_of(work, struct rtc_device, uie_task);
55 err = rtc_read_time(rtc, &tm);
57 spin_lock_irq(&rtc->irq_lock);
58 if (rtc->stop_uie_polling || err) {
59 rtc->uie_task_active = 0;
60 } else if (rtc->oldsecs != tm.tm_sec) {
61 num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
62 rtc->oldsecs = tm.tm_sec;
63 rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
64 rtc->uie_timer_active = 1;
65 rtc->uie_task_active = 0;
66 add_timer(&rtc->uie_timer);
67 } else if (schedule_work(&rtc->uie_task) == 0) {
68 rtc->uie_task_active = 0;
70 spin_unlock_irq(&rtc->irq_lock);
72 rtc_handle_legacy_irq(rtc, num, RTC_UF);
74 static void rtc_uie_timer(struct timer_list *t)
76 struct rtc_device *rtc = from_timer(rtc, t, uie_timer);
79 spin_lock_irqsave(&rtc->irq_lock, flags);
80 rtc->uie_timer_active = 0;
81 rtc->uie_task_active = 1;
82 if ((schedule_work(&rtc->uie_task) == 0))
83 rtc->uie_task_active = 0;
84 spin_unlock_irqrestore(&rtc->irq_lock, flags);
87 static int clear_uie(struct rtc_device *rtc)
89 spin_lock_irq(&rtc->irq_lock);
90 if (rtc->uie_irq_active) {
91 rtc->stop_uie_polling = 1;
92 if (rtc->uie_timer_active) {
93 spin_unlock_irq(&rtc->irq_lock);
94 del_timer_sync(&rtc->uie_timer);
95 spin_lock_irq(&rtc->irq_lock);
96 rtc->uie_timer_active = 0;
98 if (rtc->uie_task_active) {
99 spin_unlock_irq(&rtc->irq_lock);
100 flush_scheduled_work();
101 spin_lock_irq(&rtc->irq_lock);
103 rtc->uie_irq_active = 0;
105 spin_unlock_irq(&rtc->irq_lock);
109 static int set_uie(struct rtc_device *rtc)
114 err = rtc_read_time(rtc, &tm);
117 spin_lock_irq(&rtc->irq_lock);
118 if (!rtc->uie_irq_active) {
119 rtc->uie_irq_active = 1;
120 rtc->stop_uie_polling = 0;
121 rtc->oldsecs = tm.tm_sec;
122 rtc->uie_task_active = 1;
123 if (schedule_work(&rtc->uie_task) == 0)
124 rtc->uie_task_active = 0;
127 spin_unlock_irq(&rtc->irq_lock);
131 int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled)
136 return clear_uie(rtc);
138 EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul);
140 #endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
143 rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
145 struct rtc_device *rtc = file->private_data;
147 DECLARE_WAITQUEUE(wait, current);
151 if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
154 add_wait_queue(&rtc->irq_queue, &wait);
156 __set_current_state(TASK_INTERRUPTIBLE);
158 spin_lock_irq(&rtc->irq_lock);
159 data = rtc->irq_data;
161 spin_unlock_irq(&rtc->irq_lock);
167 if (file->f_flags & O_NONBLOCK) {
171 if (signal_pending(current)) {
177 set_current_state(TASK_RUNNING);
178 remove_wait_queue(&rtc->irq_queue, &wait);
181 if (sizeof(int) != sizeof(long) &&
182 count == sizeof(unsigned int))
183 ret = put_user(data, (unsigned int __user *)buf) ?:
184 sizeof(unsigned int);
186 ret = put_user(data, (unsigned long __user *)buf) ?:
187 sizeof(unsigned long);
192 static __poll_t rtc_dev_poll(struct file *file, poll_table *wait)
194 struct rtc_device *rtc = file->private_data;
197 poll_wait(file, &rtc->irq_queue, wait);
199 data = rtc->irq_data;
201 return (data != 0) ? (EPOLLIN | EPOLLRDNORM) : 0;
204 static long rtc_dev_ioctl(struct file *file,
205 unsigned int cmd, unsigned long arg)
208 struct rtc_device *rtc = file->private_data;
209 const struct rtc_class_ops *ops = rtc->ops;
211 struct rtc_wkalrm alarm;
212 void __user *uarg = (void __user *) arg;
214 err = mutex_lock_interruptible(&rtc->ops_lock);
218 /* check that the calling task has appropriate permissions
219 * for certain ioctls. doing this check here is useful
220 * to avoid duplicate code in each driver.
225 if (!capable(CAP_SYS_TIME))
230 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
235 if (rtc->irq_freq > rtc->max_user_freq &&
236 !capable(CAP_SYS_RESOURCE))
245 * Drivers *SHOULD NOT* provide ioctl implementations
246 * for these requests. Instead, provide methods to
247 * support the following code, so that the RTC's main
248 * features are accessible without using ioctls.
250 * RTC and alarm times will be in UTC, by preference,
251 * but dual-booting with MS-Windows implies RTCs must
252 * use the local wall clock time.
257 mutex_unlock(&rtc->ops_lock);
259 err = rtc_read_alarm(rtc, &alarm);
263 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
268 mutex_unlock(&rtc->ops_lock);
270 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
275 alarm.time.tm_wday = -1;
276 alarm.time.tm_yday = -1;
277 alarm.time.tm_isdst = -1;
279 /* RTC_ALM_SET alarms may be up to 24 hours in the future.
280 * Rather than expecting every RTC to implement "don't care"
281 * for day/month/year fields, just force the alarm to have
282 * the right values for those fields.
284 * RTC_WKALM_SET should be used instead. Not only does it
285 * eliminate the need for a separate RTC_AIE_ON call, it
286 * doesn't have the "alarm 23:59:59 in the future" race.
288 * NOTE: some legacy code may have used invalid fields as
289 * wildcards, exposing hardware "periodic alarm" capabilities.
290 * Not supported here.
295 err = rtc_read_time(rtc, &tm);
298 now = rtc_tm_to_time64(&tm);
300 alarm.time.tm_mday = tm.tm_mday;
301 alarm.time.tm_mon = tm.tm_mon;
302 alarm.time.tm_year = tm.tm_year;
303 err = rtc_valid_tm(&alarm.time);
306 then = rtc_tm_to_time64(&alarm.time);
308 /* alarm may need to wrap into tomorrow */
310 rtc_time64_to_tm(now + 24 * 60 * 60, &tm);
311 alarm.time.tm_mday = tm.tm_mday;
312 alarm.time.tm_mon = tm.tm_mon;
313 alarm.time.tm_year = tm.tm_year;
317 return rtc_set_alarm(rtc, &alarm);
320 mutex_unlock(&rtc->ops_lock);
322 err = rtc_read_time(rtc, &tm);
326 if (copy_to_user(uarg, &tm, sizeof(tm)))
331 mutex_unlock(&rtc->ops_lock);
333 if (copy_from_user(&tm, uarg, sizeof(tm)))
336 return rtc_set_time(rtc, &tm);
339 err = rtc_irq_set_state(rtc, 1);
343 err = rtc_irq_set_state(rtc, 0);
347 mutex_unlock(&rtc->ops_lock);
348 return rtc_alarm_irq_enable(rtc, 1);
351 mutex_unlock(&rtc->ops_lock);
352 return rtc_alarm_irq_enable(rtc, 0);
355 mutex_unlock(&rtc->ops_lock);
356 return rtc_update_irq_enable(rtc, 1);
359 mutex_unlock(&rtc->ops_lock);
360 return rtc_update_irq_enable(rtc, 0);
363 err = rtc_irq_set_freq(rtc, arg);
367 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
371 mutex_unlock(&rtc->ops_lock);
372 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
375 return rtc_set_alarm(rtc, &alarm);
378 mutex_unlock(&rtc->ops_lock);
379 err = rtc_read_alarm(rtc, &alarm);
383 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
388 /* Finally try the driver's ioctl interface */
390 err = ops->ioctl(rtc->dev.parent, cmd, arg);
391 if (err == -ENOIOCTLCMD)
399 mutex_unlock(&rtc->ops_lock);
403 static int rtc_dev_fasync(int fd, struct file *file, int on)
405 struct rtc_device *rtc = file->private_data;
406 return fasync_helper(fd, file, on, &rtc->async_queue);
409 static int rtc_dev_release(struct inode *inode, struct file *file)
411 struct rtc_device *rtc = file->private_data;
413 /* We shut down the repeating IRQs that userspace enabled,
414 * since nothing is listening to them.
415 * - Update (UIE) ... currently only managed through ioctls
416 * - Periodic (PIE) ... also used through rtc_*() interface calls
418 * Leave the alarm alone; it may be set to trigger a system wakeup
419 * later, or be used by kernel code, and is a one-shot event anyway.
422 /* Keep ioctl until all drivers are converted */
423 rtc_dev_ioctl(file, RTC_UIE_OFF, 0);
424 rtc_update_irq_enable(rtc, 0);
425 rtc_irq_set_state(rtc, 0);
427 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
431 static const struct file_operations rtc_dev_fops = {
432 .owner = THIS_MODULE,
434 .read = rtc_dev_read,
435 .poll = rtc_dev_poll,
436 .unlocked_ioctl = rtc_dev_ioctl,
437 .open = rtc_dev_open,
438 .release = rtc_dev_release,
439 .fasync = rtc_dev_fasync,
442 /* insertion/removal hooks */
444 void rtc_dev_prepare(struct rtc_device *rtc)
449 if (rtc->id >= RTC_DEV_MAX) {
450 dev_dbg(&rtc->dev, "too many RTC devices\n");
454 rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
456 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
457 INIT_WORK(&rtc->uie_task, rtc_uie_task);
458 timer_setup(&rtc->uie_timer, rtc_uie_timer, 0);
461 cdev_init(&rtc->char_dev, &rtc_dev_fops);
462 rtc->char_dev.owner = rtc->owner;
465 void __init rtc_dev_init(void)
469 err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
471 pr_err("failed to allocate char dev region\n");
474 void __exit rtc_dev_exit(void)
477 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);